diff options
Diffstat (limited to 'drivers/gpu/drm/display/drm_dp_mst_topology.c')
| -rw-r--r-- | drivers/gpu/drm/display/drm_dp_mst_topology.c | 5929 |
1 files changed, 5929 insertions, 0 deletions
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c new file mode 100644 index 000000000..72b2b171e --- /dev/null +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -0,0 +1,5929 @@ +/* + * Copyright © 2014 Red Hat + * + * Permission to use, copy, modify, distribute, and sell this software and its + * documentation for any purpose is hereby granted without fee, provided that + * the above copyright notice appear in all copies and that both that copyright + * notice and this permission notice appear in supporting documentation, and + * that the name of the copyright holders not be used in advertising or + * publicity pertaining to distribution of the software without specific, + * written prior permission. The copyright holders make no representations + * about the suitability of this software for any purpose. It is provided "as + * is" without express or implied warranty. + * + * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, + * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO + * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR + * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, + * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER + * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE + * OF THIS SOFTWARE. + */ + +#include <linux/bitfield.h> +#include <linux/delay.h> +#include <linux/errno.h> +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/random.h> +#include <linux/sched.h> +#include <linux/seq_file.h> +#include <linux/iopoll.h> + +#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS) +#include <linux/stacktrace.h> +#include <linux/sort.h> +#include <linux/timekeeping.h> +#include <linux/math64.h> +#endif + +#include <drm/display/drm_dp_mst_helper.h> +#include <drm/drm_atomic.h> +#include <drm/drm_atomic_helper.h> +#include <drm/drm_drv.h> +#include <drm/drm_edid.h> +#include <drm/drm_print.h> +#include <drm/drm_probe_helper.h> + +#include "drm_dp_helper_internal.h" +#include "drm_dp_mst_topology_internal.h" + +/** + * DOC: dp mst helper + * + * These functions contain parts of the DisplayPort 1.2a MultiStream Transport + * protocol. The helpers contain a topology manager and bandwidth manager. + * The helpers encapsulate the sending and received of sideband msgs. + */ +struct drm_dp_pending_up_req { + struct drm_dp_sideband_msg_hdr hdr; + struct drm_dp_sideband_msg_req_body msg; + struct list_head next; +}; + +static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr, + char *buf); + +static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port); + +static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr, + int id, u8 start_slot, u8 num_slots); + +static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port, + int offset, int size, u8 *bytes); +static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port, + int offset, int size, u8 *bytes); + +static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_branch *mstb); + +static void +drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_branch *mstb); + +static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_branch *mstb, + struct drm_dp_mst_port *port); +static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr, + u8 *guid); + +static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port); +static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port); +static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr); + +static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port, + struct drm_dp_mst_branch *branch); + +#define DBG_PREFIX "[dp_mst]" + +#define DP_STR(x) [DP_ ## x] = #x + +static const char *drm_dp_mst_req_type_str(u8 req_type) +{ + static const char * const req_type_str[] = { + DP_STR(GET_MSG_TRANSACTION_VERSION), + DP_STR(LINK_ADDRESS), + DP_STR(CONNECTION_STATUS_NOTIFY), + DP_STR(ENUM_PATH_RESOURCES), + DP_STR(ALLOCATE_PAYLOAD), + DP_STR(QUERY_PAYLOAD), + DP_STR(RESOURCE_STATUS_NOTIFY), + DP_STR(CLEAR_PAYLOAD_ID_TABLE), + DP_STR(REMOTE_DPCD_READ), + DP_STR(REMOTE_DPCD_WRITE), + DP_STR(REMOTE_I2C_READ), + DP_STR(REMOTE_I2C_WRITE), + DP_STR(POWER_UP_PHY), + DP_STR(POWER_DOWN_PHY), + DP_STR(SINK_EVENT_NOTIFY), + DP_STR(QUERY_STREAM_ENC_STATUS), + }; + + if (req_type >= ARRAY_SIZE(req_type_str) || + !req_type_str[req_type]) + return "unknown"; + + return req_type_str[req_type]; +} + +#undef DP_STR +#define DP_STR(x) [DP_NAK_ ## x] = #x + +static const char *drm_dp_mst_nak_reason_str(u8 nak_reason) +{ + static const char * const nak_reason_str[] = { + DP_STR(WRITE_FAILURE), + DP_STR(INVALID_READ), + DP_STR(CRC_FAILURE), + DP_STR(BAD_PARAM), + DP_STR(DEFER), + DP_STR(LINK_FAILURE), + DP_STR(NO_RESOURCES), + DP_STR(DPCD_FAIL), + DP_STR(I2C_NAK), + DP_STR(ALLOCATE_FAIL), + }; + + if (nak_reason >= ARRAY_SIZE(nak_reason_str) || + !nak_reason_str[nak_reason]) + return "unknown"; + + return nak_reason_str[nak_reason]; +} + +#undef DP_STR +#define DP_STR(x) [DRM_DP_SIDEBAND_TX_ ## x] = #x + +static const char *drm_dp_mst_sideband_tx_state_str(int state) +{ + static const char * const sideband_reason_str[] = { + DP_STR(QUEUED), + DP_STR(START_SEND), + DP_STR(SENT), + DP_STR(RX), + DP_STR(TIMEOUT), + }; + + if (state >= ARRAY_SIZE(sideband_reason_str) || + !sideband_reason_str[state]) + return "unknown"; + + return sideband_reason_str[state]; +} + +static int +drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len) +{ + int i; + u8 unpacked_rad[16]; + + for (i = 0; i < lct; i++) { + if (i % 2) + unpacked_rad[i] = rad[i / 2] >> 4; + else + unpacked_rad[i] = rad[i / 2] & BIT_MASK(4); + } + + /* TODO: Eventually add something to printk so we can format the rad + * like this: 1.2.3 + */ + return snprintf(out, len, "%*phC", lct, unpacked_rad); +} + +/* sideband msg handling */ +static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles) +{ + u8 bitmask = 0x80; + u8 bitshift = 7; + u8 array_index = 0; + int number_of_bits = num_nibbles * 4; + u8 remainder = 0; + + while (number_of_bits != 0) { + number_of_bits--; + remainder <<= 1; + remainder |= (data[array_index] & bitmask) >> bitshift; + bitmask >>= 1; + bitshift--; + if (bitmask == 0) { + bitmask = 0x80; + bitshift = 7; + array_index++; + } + if ((remainder & 0x10) == 0x10) + remainder ^= 0x13; + } + + number_of_bits = 4; + while (number_of_bits != 0) { + number_of_bits--; + remainder <<= 1; + if ((remainder & 0x10) != 0) + remainder ^= 0x13; + } + + return remainder; +} + +static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes) +{ + u8 bitmask = 0x80; + u8 bitshift = 7; + u8 array_index = 0; + int number_of_bits = number_of_bytes * 8; + u16 remainder = 0; + + while (number_of_bits != 0) { + number_of_bits--; + remainder <<= 1; + remainder |= (data[array_index] & bitmask) >> bitshift; + bitmask >>= 1; + bitshift--; + if (bitmask == 0) { + bitmask = 0x80; + bitshift = 7; + array_index++; + } + if ((remainder & 0x100) == 0x100) + remainder ^= 0xd5; + } + + number_of_bits = 8; + while (number_of_bits != 0) { + number_of_bits--; + remainder <<= 1; + if ((remainder & 0x100) != 0) + remainder ^= 0xd5; + } + + return remainder & 0xff; +} +static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr) +{ + u8 size = 3; + + size += (hdr->lct / 2); + return size; +} + +static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr, + u8 *buf, int *len) +{ + int idx = 0; + int i; + u8 crc4; + + buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf); + for (i = 0; i < (hdr->lct / 2); i++) + buf[idx++] = hdr->rad[i]; + buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) | + (hdr->msg_len & 0x3f); + buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4); + + crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1); + buf[idx - 1] |= (crc4 & 0xf); + + *len = idx; +} + +static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_sideband_msg_hdr *hdr, + u8 *buf, int buflen, u8 *hdrlen) +{ + u8 crc4; + u8 len; + int i; + u8 idx; + + if (buf[0] == 0) + return false; + len = 3; + len += ((buf[0] & 0xf0) >> 4) / 2; + if (len > buflen) + return false; + crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1); + + if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) { + drm_dbg_kms(mgr->dev, "crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]); + return false; + } + + hdr->lct = (buf[0] & 0xf0) >> 4; + hdr->lcr = (buf[0] & 0xf); + idx = 1; + for (i = 0; i < (hdr->lct / 2); i++) + hdr->rad[i] = buf[idx++]; + hdr->broadcast = (buf[idx] >> 7) & 0x1; + hdr->path_msg = (buf[idx] >> 6) & 0x1; + hdr->msg_len = buf[idx] & 0x3f; + idx++; + hdr->somt = (buf[idx] >> 7) & 0x1; + hdr->eomt = (buf[idx] >> 6) & 0x1; + hdr->seqno = (buf[idx] >> 4) & 0x1; + idx++; + *hdrlen = idx; + return true; +} + +void +drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req, + struct drm_dp_sideband_msg_tx *raw) +{ + int idx = 0; + int i; + u8 *buf = raw->msg; + + buf[idx++] = req->req_type & 0x7f; + + switch (req->req_type) { + case DP_ENUM_PATH_RESOURCES: + case DP_POWER_DOWN_PHY: + case DP_POWER_UP_PHY: + buf[idx] = (req->u.port_num.port_number & 0xf) << 4; + idx++; + break; + case DP_ALLOCATE_PAYLOAD: + buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 | + (req->u.allocate_payload.number_sdp_streams & 0xf); + idx++; + buf[idx] = (req->u.allocate_payload.vcpi & 0x7f); + idx++; + buf[idx] = (req->u.allocate_payload.pbn >> 8); + idx++; + buf[idx] = (req->u.allocate_payload.pbn & 0xff); + idx++; + for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) { + buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) | + (req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf); + idx++; + } + if (req->u.allocate_payload.number_sdp_streams & 1) { + i = req->u.allocate_payload.number_sdp_streams - 1; + buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4; + idx++; + } + break; + case DP_QUERY_PAYLOAD: + buf[idx] = (req->u.query_payload.port_number & 0xf) << 4; + idx++; + buf[idx] = (req->u.query_payload.vcpi & 0x7f); + idx++; + break; + case DP_REMOTE_DPCD_READ: + buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4; + buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf; + idx++; + buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8; + idx++; + buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff); + idx++; + buf[idx] = (req->u.dpcd_read.num_bytes); + idx++; + break; + + case DP_REMOTE_DPCD_WRITE: + buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4; + buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf; + idx++; + buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8; + idx++; + buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff); + idx++; + buf[idx] = (req->u.dpcd_write.num_bytes); + idx++; + memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes); + idx += req->u.dpcd_write.num_bytes; + break; + case DP_REMOTE_I2C_READ: + buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4; + buf[idx] |= (req->u.i2c_read.num_transactions & 0x3); + idx++; + for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) { + buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f; + idx++; + buf[idx] = req->u.i2c_read.transactions[i].num_bytes; + idx++; + memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes); + idx += req->u.i2c_read.transactions[i].num_bytes; + + buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 4; + buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf); + idx++; + } + buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f; + idx++; + buf[idx] = (req->u.i2c_read.num_bytes_read); + idx++; + break; + + case DP_REMOTE_I2C_WRITE: + buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4; + idx++; + buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f; + idx++; + buf[idx] = (req->u.i2c_write.num_bytes); + idx++; + memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes); + idx += req->u.i2c_write.num_bytes; + break; + case DP_QUERY_STREAM_ENC_STATUS: { + const struct drm_dp_query_stream_enc_status *msg; + + msg = &req->u.enc_status; + buf[idx] = msg->stream_id; + idx++; + memcpy(&buf[idx], msg->client_id, sizeof(msg->client_id)); + idx += sizeof(msg->client_id); + buf[idx] = 0; + buf[idx] |= FIELD_PREP(GENMASK(1, 0), msg->stream_event); + buf[idx] |= msg->valid_stream_event ? BIT(2) : 0; + buf[idx] |= FIELD_PREP(GENMASK(4, 3), msg->stream_behavior); + buf[idx] |= msg->valid_stream_behavior ? BIT(5) : 0; + idx++; + } + break; + } + raw->cur_len = idx; +} +EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_encode_sideband_req); + +/* Decode a sideband request we've encoded, mainly used for debugging */ +int +drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw, + struct drm_dp_sideband_msg_req_body *req) +{ + const u8 *buf = raw->msg; + int i, idx = 0; + + req->req_type = buf[idx++] & 0x7f; + switch (req->req_type) { + case DP_ENUM_PATH_RESOURCES: + case DP_POWER_DOWN_PHY: + case DP_POWER_UP_PHY: + req->u.port_num.port_number = (buf[idx] >> 4) & 0xf; + break; + case DP_ALLOCATE_PAYLOAD: + { + struct drm_dp_allocate_payload *a = + &req->u.allocate_payload; + + a->number_sdp_streams = buf[idx] & 0xf; + a->port_number = (buf[idx] >> 4) & 0xf; + + WARN_ON(buf[++idx] & 0x80); + a->vcpi = buf[idx] & 0x7f; + + a->pbn = buf[++idx] << 8; + a->pbn |= buf[++idx]; + + idx++; + for (i = 0; i < a->number_sdp_streams; i++) { + a->sdp_stream_sink[i] = + (buf[idx + (i / 2)] >> ((i % 2) ? 0 : 4)) & 0xf; + } + } + break; + case DP_QUERY_PAYLOAD: + req->u.query_payload.port_number = (buf[idx] >> 4) & 0xf; + WARN_ON(buf[++idx] & 0x80); + req->u.query_payload.vcpi = buf[idx] & 0x7f; + break; + case DP_REMOTE_DPCD_READ: + { + struct drm_dp_remote_dpcd_read *r = &req->u.dpcd_read; + + r->port_number = (buf[idx] >> 4) & 0xf; + + r->dpcd_address = (buf[idx] << 16) & 0xf0000; + r->dpcd_address |= (buf[++idx] << 8) & 0xff00; + r->dpcd_address |= buf[++idx] & 0xff; + + r->num_bytes = buf[++idx]; + } + break; + case DP_REMOTE_DPCD_WRITE: + { + struct drm_dp_remote_dpcd_write *w = + &req->u.dpcd_write; + + w->port_number = (buf[idx] >> 4) & 0xf; + + w->dpcd_address = (buf[idx] << 16) & 0xf0000; + w->dpcd_address |= (buf[++idx] << 8) & 0xff00; + w->dpcd_address |= buf[++idx] & 0xff; + + w->num_bytes = buf[++idx]; + + w->bytes = kmemdup(&buf[++idx], w->num_bytes, + GFP_KERNEL); + if (!w->bytes) + return -ENOMEM; + } + break; + case DP_REMOTE_I2C_READ: + { + struct drm_dp_remote_i2c_read *r = &req->u.i2c_read; + struct drm_dp_remote_i2c_read_tx *tx; + bool failed = false; + + r->num_transactions = buf[idx] & 0x3; + r->port_number = (buf[idx] >> 4) & 0xf; + for (i = 0; i < r->num_transactions; i++) { + tx = &r->transactions[i]; + + tx->i2c_dev_id = buf[++idx] & 0x7f; + tx->num_bytes = buf[++idx]; + tx->bytes = kmemdup(&buf[++idx], + tx->num_bytes, + GFP_KERNEL); + if (!tx->bytes) { + failed = true; + break; + } + idx += tx->num_bytes; + tx->no_stop_bit = (buf[idx] >> 5) & 0x1; + tx->i2c_transaction_delay = buf[idx] & 0xf; + } + + if (failed) { + for (i = 0; i < r->num_transactions; i++) { + tx = &r->transactions[i]; + kfree(tx->bytes); + } + return -ENOMEM; + } + + r->read_i2c_device_id = buf[++idx] & 0x7f; + r->num_bytes_read = buf[++idx]; + } + break; + case DP_REMOTE_I2C_WRITE: + { + struct drm_dp_remote_i2c_write *w = &req->u.i2c_write; + + w->port_number = (buf[idx] >> 4) & 0xf; + w->write_i2c_device_id = buf[++idx] & 0x7f; + w->num_bytes = buf[++idx]; + w->bytes = kmemdup(&buf[++idx], w->num_bytes, + GFP_KERNEL); + if (!w->bytes) + return -ENOMEM; + } + break; + case DP_QUERY_STREAM_ENC_STATUS: + req->u.enc_status.stream_id = buf[idx++]; + for (i = 0; i < sizeof(req->u.enc_status.client_id); i++) + req->u.enc_status.client_id[i] = buf[idx++]; + + req->u.enc_status.stream_event = FIELD_GET(GENMASK(1, 0), + buf[idx]); + req->u.enc_status.valid_stream_event = FIELD_GET(BIT(2), + buf[idx]); + req->u.enc_status.stream_behavior = FIELD_GET(GENMASK(4, 3), + buf[idx]); + req->u.enc_status.valid_stream_behavior = FIELD_GET(BIT(5), + buf[idx]); + break; + } + + return 0; +} +EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_decode_sideband_req); + +void +drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req, + int indent, struct drm_printer *printer) +{ + int i; + +#define P(f, ...) drm_printf_indent(printer, indent, f, ##__VA_ARGS__) + if (req->req_type == DP_LINK_ADDRESS) { + /* No contents to print */ + P("type=%s\n", drm_dp_mst_req_type_str(req->req_type)); + return; + } + + P("type=%s contents:\n", drm_dp_mst_req_type_str(req->req_type)); + indent++; + + switch (req->req_type) { + case DP_ENUM_PATH_RESOURCES: + case DP_POWER_DOWN_PHY: + case DP_POWER_UP_PHY: + P("port=%d\n", req->u.port_num.port_number); + break; + case DP_ALLOCATE_PAYLOAD: + P("port=%d vcpi=%d pbn=%d sdp_streams=%d %*ph\n", + req->u.allocate_payload.port_number, + req->u.allocate_payload.vcpi, req->u.allocate_payload.pbn, + req->u.allocate_payload.number_sdp_streams, + req->u.allocate_payload.number_sdp_streams, + req->u.allocate_payload.sdp_stream_sink); + break; + case DP_QUERY_PAYLOAD: + P("port=%d vcpi=%d\n", + req->u.query_payload.port_number, + req->u.query_payload.vcpi); + break; + case DP_REMOTE_DPCD_READ: + P("port=%d dpcd_addr=%05x len=%d\n", + req->u.dpcd_read.port_number, req->u.dpcd_read.dpcd_address, + req->u.dpcd_read.num_bytes); + break; + case DP_REMOTE_DPCD_WRITE: + P("port=%d addr=%05x len=%d: %*ph\n", + req->u.dpcd_write.port_number, + req->u.dpcd_write.dpcd_address, + req->u.dpcd_write.num_bytes, req->u.dpcd_write.num_bytes, + req->u.dpcd_write.bytes); + break; + case DP_REMOTE_I2C_READ: + P("port=%d num_tx=%d id=%d size=%d:\n", + req->u.i2c_read.port_number, + req->u.i2c_read.num_transactions, + req->u.i2c_read.read_i2c_device_id, + req->u.i2c_read.num_bytes_read); + + indent++; + for (i = 0; i < req->u.i2c_read.num_transactions; i++) { + const struct drm_dp_remote_i2c_read_tx *rtx = + &req->u.i2c_read.transactions[i]; + + P("%d: id=%03d size=%03d no_stop_bit=%d tx_delay=%03d: %*ph\n", + i, rtx->i2c_dev_id, rtx->num_bytes, + rtx->no_stop_bit, rtx->i2c_transaction_delay, + rtx->num_bytes, rtx->bytes); + } + break; + case DP_REMOTE_I2C_WRITE: + P("port=%d id=%d size=%d: %*ph\n", + req->u.i2c_write.port_number, + req->u.i2c_write.write_i2c_device_id, + req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes, + req->u.i2c_write.bytes); + break; + case DP_QUERY_STREAM_ENC_STATUS: + P("stream_id=%u client_id=%*ph stream_event=%x " + "valid_event=%d stream_behavior=%x valid_behavior=%d", + req->u.enc_status.stream_id, + (int)ARRAY_SIZE(req->u.enc_status.client_id), + req->u.enc_status.client_id, req->u.enc_status.stream_event, + req->u.enc_status.valid_stream_event, + req->u.enc_status.stream_behavior, + req->u.enc_status.valid_stream_behavior); + break; + default: + P("???\n"); + break; + } +#undef P +} +EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_dump_sideband_msg_req_body); + +static inline void +drm_dp_mst_dump_sideband_msg_tx(struct drm_printer *p, + const struct drm_dp_sideband_msg_tx *txmsg) +{ + struct drm_dp_sideband_msg_req_body req; + char buf[64]; + int ret; + int i; + + drm_dp_mst_rad_to_str(txmsg->dst->rad, txmsg->dst->lct, buf, + sizeof(buf)); + drm_printf(p, "txmsg cur_offset=%x cur_len=%x seqno=%x state=%s path_msg=%d dst=%s\n", + txmsg->cur_offset, txmsg->cur_len, txmsg->seqno, + drm_dp_mst_sideband_tx_state_str(txmsg->state), + txmsg->path_msg, buf); + + ret = drm_dp_decode_sideband_req(txmsg, &req); + if (ret) { + drm_printf(p, "<failed to decode sideband req: %d>\n", ret); + return; + } + drm_dp_dump_sideband_msg_req_body(&req, 1, p); + + switch (req.req_type) { + case DP_REMOTE_DPCD_WRITE: + kfree(req.u.dpcd_write.bytes); + break; + case DP_REMOTE_I2C_READ: + for (i = 0; i < req.u.i2c_read.num_transactions; i++) + kfree(req.u.i2c_read.transactions[i].bytes); + break; + case DP_REMOTE_I2C_WRITE: + kfree(req.u.i2c_write.bytes); + break; + } +} + +static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len) +{ + u8 crc4; + + crc4 = drm_dp_msg_data_crc4(msg, len); + msg[len] = crc4; +} + +static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep, + struct drm_dp_sideband_msg_tx *raw) +{ + int idx = 0; + u8 *buf = raw->msg; + + buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f); + + raw->cur_len = idx; +} + +static int drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx *msg, + struct drm_dp_sideband_msg_hdr *hdr, + u8 hdrlen) +{ + /* + * ignore out-of-order messages or messages that are part of a + * failed transaction + */ + if (!hdr->somt && !msg->have_somt) + return false; + + /* get length contained in this portion */ + msg->curchunk_idx = 0; + msg->curchunk_len = hdr->msg_len; + msg->curchunk_hdrlen = hdrlen; + + /* we have already gotten an somt - don't bother parsing */ + if (hdr->somt && msg->have_somt) + return false; + + if (hdr->somt) { + memcpy(&msg->initial_hdr, hdr, + sizeof(struct drm_dp_sideband_msg_hdr)); + msg->have_somt = true; + } + if (hdr->eomt) + msg->have_eomt = true; + + return true; +} + +/* this adds a chunk of msg to the builder to get the final msg */ +static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg, + u8 *replybuf, u8 replybuflen) +{ + u8 crc4; + + memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen); + msg->curchunk_idx += replybuflen; + + if (msg->curchunk_idx >= msg->curchunk_len) { + /* do CRC */ + crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1); + if (crc4 != msg->chunk[msg->curchunk_len - 1]) + print_hex_dump(KERN_DEBUG, "wrong crc", + DUMP_PREFIX_NONE, 16, 1, + msg->chunk, msg->curchunk_len, false); + /* copy chunk into bigger msg */ + memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1); + msg->curlen += msg->curchunk_len - 1; + } + return true; +} + +static bool drm_dp_sideband_parse_link_address(const struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_sideband_msg_rx *raw, + struct drm_dp_sideband_msg_reply_body *repmsg) +{ + int idx = 1; + int i; + + memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16); + idx += 16; + repmsg->u.link_addr.nports = raw->msg[idx] & 0xf; + idx++; + if (idx > raw->curlen) + goto fail_len; + for (i = 0; i < repmsg->u.link_addr.nports; i++) { + if (raw->msg[idx] & 0x80) + repmsg->u.link_addr.ports[i].input_port = 1; + + repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7; + repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf); + + idx++; + if (idx > raw->curlen) + goto fail_len; + repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1; + repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1; + if (repmsg->u.link_addr.ports[i].input_port == 0) + repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1; + idx++; + if (idx > raw->curlen) + goto fail_len; + if (repmsg->u.link_addr.ports[i].input_port == 0) { + repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]); + idx++; + if (idx > raw->curlen) + goto fail_len; + memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16); + idx += 16; + if (idx > raw->curlen) + goto fail_len; + repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf; + repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf); + idx++; + + } + if (idx > raw->curlen) + goto fail_len; + } + + return true; +fail_len: + DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen); + return false; +} + +static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw, + struct drm_dp_sideband_msg_reply_body *repmsg) +{ + int idx = 1; + + repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf; + idx++; + if (idx > raw->curlen) + goto fail_len; + repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx]; + idx++; + if (idx > raw->curlen) + goto fail_len; + + memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes); + return true; +fail_len: + DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen); + return false; +} + +static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw, + struct drm_dp_sideband_msg_reply_body *repmsg) +{ + int idx = 1; + + repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf; + idx++; + if (idx > raw->curlen) + goto fail_len; + return true; +fail_len: + DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen); + return false; +} + +static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw, + struct drm_dp_sideband_msg_reply_body *repmsg) +{ + int idx = 1; + + repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf); + idx++; + if (idx > raw->curlen) + goto fail_len; + repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx]; + idx++; + /* TODO check */ + memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes); + return true; +fail_len: + DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen); + return false; +} + +static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw, + struct drm_dp_sideband_msg_reply_body *repmsg) +{ + int idx = 1; + + repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf; + repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1; + idx++; + if (idx > raw->curlen) + goto fail_len; + repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]); + idx += 2; + if (idx > raw->curlen) + goto fail_len; + repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]); + idx += 2; + if (idx > raw->curlen) + goto fail_len; + return true; +fail_len: + DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen); + return false; +} + +static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw, + struct drm_dp_sideband_msg_reply_body *repmsg) +{ + int idx = 1; + + repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf; + idx++; + if (idx > raw->curlen) + goto fail_len; + repmsg->u.allocate_payload.vcpi = raw->msg[idx]; + idx++; + if (idx > raw->curlen) + goto fail_len; + repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]); + idx += 2; + if (idx > raw->curlen) + goto fail_len; + return true; +fail_len: + DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen); + return false; +} + +static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw, + struct drm_dp_sideband_msg_reply_body *repmsg) +{ + int idx = 1; + + repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf; + idx++; + if (idx > raw->curlen) + goto fail_len; + repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]); + idx += 2; + if (idx > raw->curlen) + goto fail_len; + return true; +fail_len: + DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen); + return false; +} + +static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw, + struct drm_dp_sideband_msg_reply_body *repmsg) +{ + int idx = 1; + + repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf; + idx++; + if (idx > raw->curlen) { + DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n", + idx, raw->curlen); + return false; + } + return true; +} + +static bool +drm_dp_sideband_parse_query_stream_enc_status( + struct drm_dp_sideband_msg_rx *raw, + struct drm_dp_sideband_msg_reply_body *repmsg) +{ + struct drm_dp_query_stream_enc_status_ack_reply *reply; + + reply = &repmsg->u.enc_status; + + reply->stream_id = raw->msg[3]; + + reply->reply_signed = raw->msg[2] & BIT(0); + + /* + * NOTE: It's my impression from reading the spec that the below parsing + * is correct. However I noticed while testing with an HDCP 1.4 display + * through an HDCP 2.2 hub that only bit 3 was set. In that case, I + * would expect both bits to be set. So keep the parsing following the + * spec, but beware reality might not match the spec (at least for some + * configurations). + */ + reply->hdcp_1x_device_present = raw->msg[2] & BIT(4); + reply->hdcp_2x_device_present = raw->msg[2] & BIT(3); + + reply->query_capable_device_present = raw->msg[2] & BIT(5); + reply->legacy_device_present = raw->msg[2] & BIT(6); + reply->unauthorizable_device_present = raw->msg[2] & BIT(7); + + reply->auth_completed = !!(raw->msg[1] & BIT(3)); + reply->encryption_enabled = !!(raw->msg[1] & BIT(4)); + reply->repeater_present = !!(raw->msg[1] & BIT(5)); + reply->state = (raw->msg[1] & GENMASK(7, 6)) >> 6; + + return true; +} + +static bool drm_dp_sideband_parse_reply(const struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_sideband_msg_rx *raw, + struct drm_dp_sideband_msg_reply_body *msg) +{ + memset(msg, 0, sizeof(*msg)); + msg->reply_type = (raw->msg[0] & 0x80) >> 7; + msg->req_type = (raw->msg[0] & 0x7f); + + if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) { + memcpy(msg->u.nak.guid, &raw->msg[1], 16); + msg->u.nak.reason = raw->msg[17]; + msg->u.nak.nak_data = raw->msg[18]; + return false; + } + + switch (msg->req_type) { + case DP_LINK_ADDRESS: + return drm_dp_sideband_parse_link_address(mgr, raw, msg); + case DP_QUERY_PAYLOAD: + return drm_dp_sideband_parse_query_payload_ack(raw, msg); + case DP_REMOTE_DPCD_READ: + return drm_dp_sideband_parse_remote_dpcd_read(raw, msg); + case DP_REMOTE_DPCD_WRITE: + return drm_dp_sideband_parse_remote_dpcd_write(raw, msg); + case DP_REMOTE_I2C_READ: + return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg); + case DP_REMOTE_I2C_WRITE: + return true; /* since there's nothing to parse */ + case DP_ENUM_PATH_RESOURCES: + return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg); + case DP_ALLOCATE_PAYLOAD: + return drm_dp_sideband_parse_allocate_payload_ack(raw, msg); + case DP_POWER_DOWN_PHY: + case DP_POWER_UP_PHY: + return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg); + case DP_CLEAR_PAYLOAD_ID_TABLE: + return true; /* since there's nothing to parse */ + case DP_QUERY_STREAM_ENC_STATUS: + return drm_dp_sideband_parse_query_stream_enc_status(raw, msg); + default: + drm_err(mgr->dev, "Got unknown reply 0x%02x (%s)\n", + msg->req_type, drm_dp_mst_req_type_str(msg->req_type)); + return false; + } +} + +static bool +drm_dp_sideband_parse_connection_status_notify(const struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_sideband_msg_rx *raw, + struct drm_dp_sideband_msg_req_body *msg) +{ + int idx = 1; + + msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4; + idx++; + if (idx > raw->curlen) + goto fail_len; + + memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16); + idx += 16; + if (idx > raw->curlen) + goto fail_len; + + msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1; + msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1; + msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1; + msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1; + msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7); + idx++; + return true; +fail_len: + drm_dbg_kms(mgr->dev, "connection status reply parse length fail %d %d\n", + idx, raw->curlen); + return false; +} + +static bool drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_sideband_msg_rx *raw, + struct drm_dp_sideband_msg_req_body *msg) +{ + int idx = 1; + + msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4; + idx++; + if (idx > raw->curlen) + goto fail_len; + + memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16); + idx += 16; + if (idx > raw->curlen) + goto fail_len; + + msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]); + idx++; + return true; +fail_len: + drm_dbg_kms(mgr->dev, "resource status reply parse length fail %d %d\n", idx, raw->curlen); + return false; +} + +static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_sideband_msg_rx *raw, + struct drm_dp_sideband_msg_req_body *msg) +{ + memset(msg, 0, sizeof(*msg)); + msg->req_type = (raw->msg[0] & 0x7f); + + switch (msg->req_type) { + case DP_CONNECTION_STATUS_NOTIFY: + return drm_dp_sideband_parse_connection_status_notify(mgr, raw, msg); + case DP_RESOURCE_STATUS_NOTIFY: + return drm_dp_sideband_parse_resource_status_notify(mgr, raw, msg); + default: + drm_err(mgr->dev, "Got unknown request 0x%02x (%s)\n", + msg->req_type, drm_dp_mst_req_type_str(msg->req_type)); + return false; + } +} + +static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg, + u8 port_num, u32 offset, u8 num_bytes, u8 *bytes) +{ + struct drm_dp_sideband_msg_req_body req; + + req.req_type = DP_REMOTE_DPCD_WRITE; + req.u.dpcd_write.port_number = port_num; + req.u.dpcd_write.dpcd_address = offset; + req.u.dpcd_write.num_bytes = num_bytes; + req.u.dpcd_write.bytes = bytes; + drm_dp_encode_sideband_req(&req, msg); +} + +static void build_link_address(struct drm_dp_sideband_msg_tx *msg) +{ + struct drm_dp_sideband_msg_req_body req; + + req.req_type = DP_LINK_ADDRESS; + drm_dp_encode_sideband_req(&req, msg); +} + +static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg) +{ + struct drm_dp_sideband_msg_req_body req; + + req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE; + drm_dp_encode_sideband_req(&req, msg); + msg->path_msg = true; +} + +static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg, + int port_num) +{ + struct drm_dp_sideband_msg_req_body req; + + req.req_type = DP_ENUM_PATH_RESOURCES; + req.u.port_num.port_number = port_num; + drm_dp_encode_sideband_req(&req, msg); + msg->path_msg = true; + return 0; +} + +static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg, + int port_num, + u8 vcpi, uint16_t pbn, + u8 number_sdp_streams, + u8 *sdp_stream_sink) +{ + struct drm_dp_sideband_msg_req_body req; + + memset(&req, 0, sizeof(req)); + req.req_type = DP_ALLOCATE_PAYLOAD; + req.u.allocate_payload.port_number = port_num; + req.u.allocate_payload.vcpi = vcpi; + req.u.allocate_payload.pbn = pbn; + req.u.allocate_payload.number_sdp_streams = number_sdp_streams; + memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink, + number_sdp_streams); + drm_dp_encode_sideband_req(&req, msg); + msg->path_msg = true; +} + +static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg, + int port_num, bool power_up) +{ + struct drm_dp_sideband_msg_req_body req; + + if (power_up) + req.req_type = DP_POWER_UP_PHY; + else + req.req_type = DP_POWER_DOWN_PHY; + + req.u.port_num.port_number = port_num; + drm_dp_encode_sideband_req(&req, msg); + msg->path_msg = true; +} + +static int +build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id, + u8 *q_id) +{ + struct drm_dp_sideband_msg_req_body req; + + req.req_type = DP_QUERY_STREAM_ENC_STATUS; + req.u.enc_status.stream_id = stream_id; + memcpy(req.u.enc_status.client_id, q_id, + sizeof(req.u.enc_status.client_id)); + req.u.enc_status.stream_event = 0; + req.u.enc_status.valid_stream_event = false; + req.u.enc_status.stream_behavior = 0; + req.u.enc_status.valid_stream_behavior = false; + + drm_dp_encode_sideband_req(&req, msg); + return 0; +} + +static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_sideband_msg_tx *txmsg) +{ + unsigned int state; + + /* + * All updates to txmsg->state are protected by mgr->qlock, and the two + * cases we check here are terminal states. For those the barriers + * provided by the wake_up/wait_event pair are enough. + */ + state = READ_ONCE(txmsg->state); + return (state == DRM_DP_SIDEBAND_TX_RX || + state == DRM_DP_SIDEBAND_TX_TIMEOUT); +} + +static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb, + struct drm_dp_sideband_msg_tx *txmsg) +{ + struct drm_dp_mst_topology_mgr *mgr = mstb->mgr; + unsigned long wait_timeout = msecs_to_jiffies(4000); + unsigned long wait_expires = jiffies + wait_timeout; + int ret; + + for (;;) { + /* + * If the driver provides a way for this, change to + * poll-waiting for the MST reply interrupt if we didn't receive + * it for 50 msec. This would cater for cases where the HPD + * pulse signal got lost somewhere, even though the sink raised + * the corresponding MST interrupt correctly. One example is the + * Club 3D CAC-1557 TypeC -> DP adapter which for some reason + * filters out short pulses with a duration less than ~540 usec. + * + * The poll period is 50 msec to avoid missing an interrupt + * after the sink has cleared it (after a 110msec timeout + * since it raised the interrupt). + */ + ret = wait_event_timeout(mgr->tx_waitq, + check_txmsg_state(mgr, txmsg), + mgr->cbs->poll_hpd_irq ? + msecs_to_jiffies(50) : + wait_timeout); + + if (ret || !mgr->cbs->poll_hpd_irq || + time_after(jiffies, wait_expires)) + break; + + mgr->cbs->poll_hpd_irq(mgr); + } + + mutex_lock(&mgr->qlock); + if (ret > 0) { + if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) { + ret = -EIO; + goto out; + } + } else { + drm_dbg_kms(mgr->dev, "timedout msg send %p %d %d\n", + txmsg, txmsg->state, txmsg->seqno); + + /* dump some state */ + ret = -EIO; + + /* remove from q */ + if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED || + txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND || + txmsg->state == DRM_DP_SIDEBAND_TX_SENT) + list_del(&txmsg->next); + } +out: + if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) { + struct drm_printer p = drm_debug_printer(DBG_PREFIX); + + drm_dp_mst_dump_sideband_msg_tx(&p, txmsg); + } + mutex_unlock(&mgr->qlock); + + drm_dp_mst_kick_tx(mgr); + return ret; +} + +static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad) +{ + struct drm_dp_mst_branch *mstb; + + mstb = kzalloc(sizeof(*mstb), GFP_KERNEL); + if (!mstb) + return NULL; + + mstb->lct = lct; + if (lct > 1) + memcpy(mstb->rad, rad, lct / 2); + INIT_LIST_HEAD(&mstb->ports); + kref_init(&mstb->topology_kref); + kref_init(&mstb->malloc_kref); + return mstb; +} + +static void drm_dp_free_mst_branch_device(struct kref *kref) +{ + struct drm_dp_mst_branch *mstb = + container_of(kref, struct drm_dp_mst_branch, malloc_kref); + + if (mstb->port_parent) + drm_dp_mst_put_port_malloc(mstb->port_parent); + + kfree(mstb); +} + +/** + * DOC: Branch device and port refcounting + * + * Topology refcount overview + * ~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * The refcounting schemes for &struct drm_dp_mst_branch and &struct + * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have + * two different kinds of refcounts: topology refcounts, and malloc refcounts. + * + * Topology refcounts are not exposed to drivers, and are handled internally + * by the DP MST helpers. The helpers use them in order to prevent the + * in-memory topology state from being changed in the middle of critical + * operations like changing the internal state of payload allocations. This + * means each branch and port will be considered to be connected to the rest + * of the topology until its topology refcount reaches zero. Additionally, + * for ports this means that their associated &struct drm_connector will stay + * registered with userspace until the port's refcount reaches 0. + * + * Malloc refcount overview + * ~~~~~~~~~~~~~~~~~~~~~~~~ + * + * Malloc references are used to keep a &struct drm_dp_mst_port or &struct + * drm_dp_mst_branch allocated even after all of its topology references have + * been dropped, so that the driver or MST helpers can safely access each + * branch's last known state before it was disconnected from the topology. + * When the malloc refcount of a port or branch reaches 0, the memory + * allocation containing the &struct drm_dp_mst_branch or &struct + * drm_dp_mst_port respectively will be freed. + * + * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed + * to drivers. As of writing this documentation, there are no drivers that + * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST + * helpers. Exposing this API to drivers in a race-free manner would take more + * tweaking of the refcounting scheme, however patches are welcome provided + * there is a legitimate driver usecase for this. + * + * Refcount relationships in a topology + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * Let's take a look at why the relationship between topology and malloc + * refcounts is designed the way it is. + * + * .. kernel-figure:: dp-mst/topology-figure-1.dot + * + * An example of topology and malloc refs in a DP MST topology with two + * active payloads. Topology refcount increments are indicated by solid + * lines, and malloc refcount increments are indicated by dashed lines. + * Each starts from the branch which incremented the refcount, and ends at + * the branch to which the refcount belongs to, i.e. the arrow points the + * same way as the C pointers used to reference a structure. + * + * As you can see in the above figure, every branch increments the topology + * refcount of its children, and increments the malloc refcount of its + * parent. Additionally, every payload increments the malloc refcount of its + * assigned port by 1. + * + * So, what would happen if MSTB #3 from the above figure was unplugged from + * the system, but the driver hadn't yet removed payload #2 from port #3? The + * topology would start to look like the figure below. + * + * .. kernel-figure:: dp-mst/topology-figure-2.dot + * + * Ports and branch devices which have been released from memory are + * colored grey, and references which have been removed are colored red. + * + * Whenever a port or branch device's topology refcount reaches zero, it will + * decrement the topology refcounts of all its children, the malloc refcount + * of its parent, and finally its own malloc refcount. For MSTB #4 and port + * #4, this means they both have been disconnected from the topology and freed + * from memory. But, because payload #2 is still holding a reference to port + * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port + * is still accessible from memory. This also means port #3 has not yet + * decremented the malloc refcount of MSTB #3, so its &struct + * drm_dp_mst_branch will also stay allocated in memory until port #3's + * malloc refcount reaches 0. + * + * This relationship is necessary because in order to release payload #2, we + * need to be able to figure out the last relative of port #3 that's still + * connected to the topology. In this case, we would travel up the topology as + * shown below. + * + * .. kernel-figure:: dp-mst/topology-figure-3.dot + * + * And finally, remove payload #2 by communicating with port #2 through + * sideband transactions. + */ + +/** + * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch + * device + * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of + * + * Increments &drm_dp_mst_branch.malloc_kref. When + * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb + * will be released and @mstb may no longer be used. + * + * See also: drm_dp_mst_put_mstb_malloc() + */ +static void +drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb) +{ + kref_get(&mstb->malloc_kref); + drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref)); +} + +/** + * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch + * device + * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of + * + * Decrements &drm_dp_mst_branch.malloc_kref. When + * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb + * will be released and @mstb may no longer be used. + * + * See also: drm_dp_mst_get_mstb_malloc() + */ +static void +drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb) +{ + drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1); + kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device); +} + +static void drm_dp_free_mst_port(struct kref *kref) +{ + struct drm_dp_mst_port *port = + container_of(kref, struct drm_dp_mst_port, malloc_kref); + + drm_dp_mst_put_mstb_malloc(port->parent); + kfree(port); +} + +/** + * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port + * @port: The &struct drm_dp_mst_port to increment the malloc refcount of + * + * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref + * reaches 0, the memory allocation for @port will be released and @port may + * no longer be used. + * + * Because @port could potentially be freed at any time by the DP MST helpers + * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this + * function, drivers that which to make use of &struct drm_dp_mst_port should + * ensure that they grab at least one main malloc reference to their MST ports + * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before + * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0. + * + * See also: drm_dp_mst_put_port_malloc() + */ +void +drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port) +{ + kref_get(&port->malloc_kref); + drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref)); +} +EXPORT_SYMBOL(drm_dp_mst_get_port_malloc); + +/** + * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port + * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of + * + * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref + * reaches 0, the memory allocation for @port will be released and @port may + * no longer be used. + * + * See also: drm_dp_mst_get_port_malloc() + */ +void +drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port) +{ + drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1); + kref_put(&port->malloc_kref, drm_dp_free_mst_port); +} +EXPORT_SYMBOL(drm_dp_mst_put_port_malloc); + +#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS) + +#define STACK_DEPTH 8 + +static noinline void +__topology_ref_save(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_topology_ref_history *history, + enum drm_dp_mst_topology_ref_type type) +{ + struct drm_dp_mst_topology_ref_entry *entry = NULL; + depot_stack_handle_t backtrace; + ulong stack_entries[STACK_DEPTH]; + uint n; + int i; + + n = stack_trace_save(stack_entries, ARRAY_SIZE(stack_entries), 1); + backtrace = stack_depot_save(stack_entries, n, GFP_KERNEL); + if (!backtrace) + return; + + /* Try to find an existing entry for this backtrace */ + for (i = 0; i < history->len; i++) { + if (history->entries[i].backtrace == backtrace) { + entry = &history->entries[i]; + break; + } + } + + /* Otherwise add one */ + if (!entry) { + struct drm_dp_mst_topology_ref_entry *new; + int new_len = history->len + 1; + + new = krealloc(history->entries, sizeof(*new) * new_len, + GFP_KERNEL); + if (!new) + return; + + entry = &new[history->len]; + history->len = new_len; + history->entries = new; + + entry->backtrace = backtrace; + entry->type = type; + entry->count = 0; + } + entry->count++; + entry->ts_nsec = ktime_get_ns(); +} + +static int +topology_ref_history_cmp(const void *a, const void *b) +{ + const struct drm_dp_mst_topology_ref_entry *entry_a = a, *entry_b = b; + + if (entry_a->ts_nsec > entry_b->ts_nsec) + return 1; + else if (entry_a->ts_nsec < entry_b->ts_nsec) + return -1; + else + return 0; +} + +static inline const char * +topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type) +{ + if (type == DRM_DP_MST_TOPOLOGY_REF_GET) + return "get"; + else + return "put"; +} + +static void +__dump_topology_ref_history(struct drm_dp_mst_topology_ref_history *history, + void *ptr, const char *type_str) +{ + struct drm_printer p = drm_debug_printer(DBG_PREFIX); + char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL); + int i; + + if (!buf) + return; + + if (!history->len) + goto out; + + /* First, sort the list so that it goes from oldest to newest + * reference entry + */ + sort(history->entries, history->len, sizeof(*history->entries), + topology_ref_history_cmp, NULL); + + drm_printf(&p, "%s (%p) topology count reached 0, dumping history:\n", + type_str, ptr); + + for (i = 0; i < history->len; i++) { + const struct drm_dp_mst_topology_ref_entry *entry = + &history->entries[i]; + u64 ts_nsec = entry->ts_nsec; + u32 rem_nsec = do_div(ts_nsec, 1000000000); + + stack_depot_snprint(entry->backtrace, buf, PAGE_SIZE, 4); + + drm_printf(&p, " %d %ss (last at %5llu.%06u):\n%s", + entry->count, + topology_ref_type_to_str(entry->type), + ts_nsec, rem_nsec / 1000, buf); + } + + /* Now free the history, since this is the only time we expose it */ + kfree(history->entries); +out: + kfree(buf); +} + +static __always_inline void +drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) +{ + __dump_topology_ref_history(&mstb->topology_ref_history, mstb, + "MSTB"); +} + +static __always_inline void +drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) +{ + __dump_topology_ref_history(&port->topology_ref_history, port, + "Port"); +} + +static __always_inline void +save_mstb_topology_ref(struct drm_dp_mst_branch *mstb, + enum drm_dp_mst_topology_ref_type type) +{ + __topology_ref_save(mstb->mgr, &mstb->topology_ref_history, type); +} + +static __always_inline void +save_port_topology_ref(struct drm_dp_mst_port *port, + enum drm_dp_mst_topology_ref_type type) +{ + __topology_ref_save(port->mgr, &port->topology_ref_history, type); +} + +static inline void +topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) +{ + mutex_lock(&mgr->topology_ref_history_lock); +} + +static inline void +topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) +{ + mutex_unlock(&mgr->topology_ref_history_lock); +} +#else +static inline void +topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {} +static inline void +topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {} +static inline void +drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) {} +static inline void +drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {} +#define save_mstb_topology_ref(mstb, type) +#define save_port_topology_ref(port, type) +#endif + +struct drm_dp_mst_atomic_payload * +drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state *state, + struct drm_dp_mst_port *port) +{ + struct drm_dp_mst_atomic_payload *payload; + + list_for_each_entry(payload, &state->payloads, next) + if (payload->port == port) + return payload; + + return NULL; +} +EXPORT_SYMBOL(drm_atomic_get_mst_payload_state); + +static void drm_dp_destroy_mst_branch_device(struct kref *kref) +{ + struct drm_dp_mst_branch *mstb = + container_of(kref, struct drm_dp_mst_branch, topology_kref); + struct drm_dp_mst_topology_mgr *mgr = mstb->mgr; + + drm_dp_mst_dump_mstb_topology_history(mstb); + + INIT_LIST_HEAD(&mstb->destroy_next); + + /* + * This can get called under mgr->mutex, so we need to perform the + * actual destruction of the mstb in another worker + */ + mutex_lock(&mgr->delayed_destroy_lock); + list_add(&mstb->destroy_next, &mgr->destroy_branch_device_list); + mutex_unlock(&mgr->delayed_destroy_lock); + queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work); +} + +/** + * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a + * branch device unless it's zero + * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of + * + * Attempts to grab a topology reference to @mstb, if it hasn't yet been + * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has + * reached 0). Holding a topology reference implies that a malloc reference + * will be held to @mstb as long as the user holds the topology reference. + * + * Care should be taken to ensure that the user has at least one malloc + * reference to @mstb. If you already have a topology reference to @mstb, you + * should use drm_dp_mst_topology_get_mstb() instead. + * + * See also: + * drm_dp_mst_topology_get_mstb() + * drm_dp_mst_topology_put_mstb() + * + * Returns: + * * 1: A topology reference was grabbed successfully + * * 0: @port is no longer in the topology, no reference was grabbed + */ +static int __must_check +drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb) +{ + int ret; + + topology_ref_history_lock(mstb->mgr); + ret = kref_get_unless_zero(&mstb->topology_kref); + if (ret) { + drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref)); + save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET); + } + + topology_ref_history_unlock(mstb->mgr); + + return ret; +} + +/** + * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a + * branch device + * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of + * + * Increments &drm_dp_mst_branch.topology_refcount without checking whether or + * not it's already reached 0. This is only valid to use in scenarios where + * you are already guaranteed to have at least one active topology reference + * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used. + * + * See also: + * drm_dp_mst_topology_try_get_mstb() + * drm_dp_mst_topology_put_mstb() + */ +static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb) +{ + topology_ref_history_lock(mstb->mgr); + + save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET); + WARN_ON(kref_read(&mstb->topology_kref) == 0); + kref_get(&mstb->topology_kref); + drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref)); + + topology_ref_history_unlock(mstb->mgr); +} + +/** + * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch + * device + * @mstb: The &struct drm_dp_mst_branch to release the topology reference from + * + * Releases a topology reference from @mstb by decrementing + * &drm_dp_mst_branch.topology_kref. + * + * See also: + * drm_dp_mst_topology_try_get_mstb() + * drm_dp_mst_topology_get_mstb() + */ +static void +drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb) +{ + topology_ref_history_lock(mstb->mgr); + + drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref) - 1); + save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_PUT); + + topology_ref_history_unlock(mstb->mgr); + kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device); +} + +static void drm_dp_destroy_port(struct kref *kref) +{ + struct drm_dp_mst_port *port = + container_of(kref, struct drm_dp_mst_port, topology_kref); + struct drm_dp_mst_topology_mgr *mgr = port->mgr; + + drm_dp_mst_dump_port_topology_history(port); + + /* There's nothing that needs locking to destroy an input port yet */ + if (port->input) { + drm_dp_mst_put_port_malloc(port); + return; + } + + kfree(port->cached_edid); + + /* + * we can't destroy the connector here, as we might be holding the + * mode_config.mutex from an EDID retrieval + */ + mutex_lock(&mgr->delayed_destroy_lock); + list_add(&port->next, &mgr->destroy_port_list); + mutex_unlock(&mgr->delayed_destroy_lock); + queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work); +} + +/** + * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a + * port unless it's zero + * @port: &struct drm_dp_mst_port to increment the topology refcount of + * + * Attempts to grab a topology reference to @port, if it hasn't yet been + * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached + * 0). Holding a topology reference implies that a malloc reference will be + * held to @port as long as the user holds the topology reference. + * + * Care should be taken to ensure that the user has at least one malloc + * reference to @port. If you already have a topology reference to @port, you + * should use drm_dp_mst_topology_get_port() instead. + * + * See also: + * drm_dp_mst_topology_get_port() + * drm_dp_mst_topology_put_port() + * + * Returns: + * * 1: A topology reference was grabbed successfully + * * 0: @port is no longer in the topology, no reference was grabbed + */ +static int __must_check +drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port) +{ + int ret; + + topology_ref_history_lock(port->mgr); + ret = kref_get_unless_zero(&port->topology_kref); + if (ret) { + drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref)); + save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET); + } + + topology_ref_history_unlock(port->mgr); + return ret; +} + +/** + * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port + * @port: The &struct drm_dp_mst_port to increment the topology refcount of + * + * Increments &drm_dp_mst_port.topology_refcount without checking whether or + * not it's already reached 0. This is only valid to use in scenarios where + * you are already guaranteed to have at least one active topology reference + * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used. + * + * See also: + * drm_dp_mst_topology_try_get_port() + * drm_dp_mst_topology_put_port() + */ +static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port) +{ + topology_ref_history_lock(port->mgr); + + WARN_ON(kref_read(&port->topology_kref) == 0); + kref_get(&port->topology_kref); + drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref)); + save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET); + + topology_ref_history_unlock(port->mgr); +} + +/** + * drm_dp_mst_topology_put_port() - release a topology reference to a port + * @port: The &struct drm_dp_mst_port to release the topology reference from + * + * Releases a topology reference from @port by decrementing + * &drm_dp_mst_port.topology_kref. + * + * See also: + * drm_dp_mst_topology_try_get_port() + * drm_dp_mst_topology_get_port() + */ +static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port) +{ + topology_ref_history_lock(port->mgr); + + drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref) - 1); + save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_PUT); + + topology_ref_history_unlock(port->mgr); + kref_put(&port->topology_kref, drm_dp_destroy_port); +} + +static struct drm_dp_mst_branch * +drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb, + struct drm_dp_mst_branch *to_find) +{ + struct drm_dp_mst_port *port; + struct drm_dp_mst_branch *rmstb; + + if (to_find == mstb) + return mstb; + + list_for_each_entry(port, &mstb->ports, next) { + if (port->mstb) { + rmstb = drm_dp_mst_topology_get_mstb_validated_locked( + port->mstb, to_find); + if (rmstb) + return rmstb; + } + } + return NULL; +} + +static struct drm_dp_mst_branch * +drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_branch *mstb) +{ + struct drm_dp_mst_branch *rmstb = NULL; + + mutex_lock(&mgr->lock); + if (mgr->mst_primary) { + rmstb = drm_dp_mst_topology_get_mstb_validated_locked( + mgr->mst_primary, mstb); + + if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb)) + rmstb = NULL; + } + mutex_unlock(&mgr->lock); + return rmstb; +} + +static struct drm_dp_mst_port * +drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb, + struct drm_dp_mst_port *to_find) +{ + struct drm_dp_mst_port *port, *mport; + + list_for_each_entry(port, &mstb->ports, next) { + if (port == to_find) + return port; + + if (port->mstb) { + mport = drm_dp_mst_topology_get_port_validated_locked( + port->mstb, to_find); + if (mport) + return mport; + } + } + return NULL; +} + +static struct drm_dp_mst_port * +drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port) +{ + struct drm_dp_mst_port *rport = NULL; + + mutex_lock(&mgr->lock); + if (mgr->mst_primary) { + rport = drm_dp_mst_topology_get_port_validated_locked( + mgr->mst_primary, port); + + if (rport && !drm_dp_mst_topology_try_get_port(rport)) + rport = NULL; + } + mutex_unlock(&mgr->lock); + return rport; +} + +static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num) +{ + struct drm_dp_mst_port *port; + int ret; + + list_for_each_entry(port, &mstb->ports, next) { + if (port->port_num == port_num) { + ret = drm_dp_mst_topology_try_get_port(port); + return ret ? port : NULL; + } + } + + return NULL; +} + +/* + * calculate a new RAD for this MST branch device + * if parent has an LCT of 2 then it has 1 nibble of RAD, + * if parent has an LCT of 3 then it has 2 nibbles of RAD, + */ +static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port, + u8 *rad) +{ + int parent_lct = port->parent->lct; + int shift = 4; + int idx = (parent_lct - 1) / 2; + + if (parent_lct > 1) { + memcpy(rad, port->parent->rad, idx + 1); + shift = (parent_lct % 2) ? 4 : 0; + } else + rad[0] = 0; + + rad[idx] |= port->port_num << shift; + return parent_lct + 1; +} + +static bool drm_dp_mst_is_end_device(u8 pdt, bool mcs) +{ + switch (pdt) { + case DP_PEER_DEVICE_DP_LEGACY_CONV: + case DP_PEER_DEVICE_SST_SINK: + return true; + case DP_PEER_DEVICE_MST_BRANCHING: + /* For sst branch device */ + if (!mcs) + return true; + + return false; + } + return true; +} + +static int +drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt, + bool new_mcs) +{ + struct drm_dp_mst_topology_mgr *mgr = port->mgr; + struct drm_dp_mst_branch *mstb; + u8 rad[8], lct; + int ret = 0; + + if (port->pdt == new_pdt && port->mcs == new_mcs) + return 0; + + /* Teardown the old pdt, if there is one */ + if (port->pdt != DP_PEER_DEVICE_NONE) { + if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) { + /* + * If the new PDT would also have an i2c bus, + * don't bother with reregistering it + */ + if (new_pdt != DP_PEER_DEVICE_NONE && + drm_dp_mst_is_end_device(new_pdt, new_mcs)) { + port->pdt = new_pdt; + port->mcs = new_mcs; + return 0; + } + + /* remove i2c over sideband */ + drm_dp_mst_unregister_i2c_bus(port); + } else { + mutex_lock(&mgr->lock); + drm_dp_mst_topology_put_mstb(port->mstb); + port->mstb = NULL; + mutex_unlock(&mgr->lock); + } + } + + port->pdt = new_pdt; + port->mcs = new_mcs; + + if (port->pdt != DP_PEER_DEVICE_NONE) { + if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) { + /* add i2c over sideband */ + ret = drm_dp_mst_register_i2c_bus(port); + } else { + lct = drm_dp_calculate_rad(port, rad); + mstb = drm_dp_add_mst_branch_device(lct, rad); + if (!mstb) { + ret = -ENOMEM; + drm_err(mgr->dev, "Failed to create MSTB for port %p", port); + goto out; + } + + mutex_lock(&mgr->lock); + port->mstb = mstb; + mstb->mgr = port->mgr; + mstb->port_parent = port; + + /* + * Make sure this port's memory allocation stays + * around until its child MSTB releases it + */ + drm_dp_mst_get_port_malloc(port); + mutex_unlock(&mgr->lock); + + /* And make sure we send a link address for this */ + ret = 1; + } + } + +out: + if (ret < 0) + port->pdt = DP_PEER_DEVICE_NONE; + return ret; +} + +/** + * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband + * @aux: Fake sideband AUX CH + * @offset: address of the (first) register to read + * @buffer: buffer to store the register values + * @size: number of bytes in @buffer + * + * Performs the same functionality for remote devices via + * sideband messaging as drm_dp_dpcd_read() does for local + * devices via actual AUX CH. + * + * Return: Number of bytes read, or negative error code on failure. + */ +ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux, + unsigned int offset, void *buffer, size_t size) +{ + struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port, + aux); + + return drm_dp_send_dpcd_read(port->mgr, port, + offset, size, buffer); +} + +/** + * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband + * @aux: Fake sideband AUX CH + * @offset: address of the (first) register to write + * @buffer: buffer containing the values to write + * @size: number of bytes in @buffer + * + * Performs the same functionality for remote devices via + * sideband messaging as drm_dp_dpcd_write() does for local + * devices via actual AUX CH. + * + * Return: number of bytes written on success, negative error code on failure. + */ +ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux, + unsigned int offset, void *buffer, size_t size) +{ + struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port, + aux); + + return drm_dp_send_dpcd_write(port->mgr, port, + offset, size, buffer); +} + +static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid) +{ + int ret = 0; + + memcpy(mstb->guid, guid, 16); + + if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) { + if (mstb->port_parent) { + ret = drm_dp_send_dpcd_write(mstb->mgr, + mstb->port_parent, + DP_GUID, 16, mstb->guid); + } else { + ret = drm_dp_dpcd_write(mstb->mgr->aux, + DP_GUID, mstb->guid, 16); + } + } + + if (ret < 16 && ret > 0) + return -EPROTO; + + return ret == 16 ? 0 : ret; +} + +static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb, + int pnum, + char *proppath, + size_t proppath_size) +{ + int i; + char temp[8]; + + snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id); + for (i = 0; i < (mstb->lct - 1); i++) { + int shift = (i % 2) ? 0 : 4; + int port_num = (mstb->rad[i / 2] >> shift) & 0xf; + + snprintf(temp, sizeof(temp), "-%d", port_num); + strlcat(proppath, temp, proppath_size); + } + snprintf(temp, sizeof(temp), "-%d", pnum); + strlcat(proppath, temp, proppath_size); +} + +/** + * drm_dp_mst_connector_late_register() - Late MST connector registration + * @connector: The MST connector + * @port: The MST port for this connector + * + * Helper to register the remote aux device for this MST port. Drivers should + * call this from their mst connector's late_register hook to enable MST aux + * devices. + * + * Return: 0 on success, negative error code on failure. + */ +int drm_dp_mst_connector_late_register(struct drm_connector *connector, + struct drm_dp_mst_port *port) +{ + drm_dbg_kms(port->mgr->dev, "registering %s remote bus for %s\n", + port->aux.name, connector->kdev->kobj.name); + + port->aux.dev = connector->kdev; + return drm_dp_aux_register_devnode(&port->aux); +} +EXPORT_SYMBOL(drm_dp_mst_connector_late_register); + +/** + * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration + * @connector: The MST connector + * @port: The MST port for this connector + * + * Helper to unregister the remote aux device for this MST port, registered by + * drm_dp_mst_connector_late_register(). Drivers should call this from their mst + * connector's early_unregister hook. + */ +void drm_dp_mst_connector_early_unregister(struct drm_connector *connector, + struct drm_dp_mst_port *port) +{ + drm_dbg_kms(port->mgr->dev, "unregistering %s remote bus for %s\n", + port->aux.name, connector->kdev->kobj.name); + drm_dp_aux_unregister_devnode(&port->aux); +} +EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister); + +static void +drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb, + struct drm_dp_mst_port *port) +{ + struct drm_dp_mst_topology_mgr *mgr = port->mgr; + char proppath[255]; + int ret; + + build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath)); + port->connector = mgr->cbs->add_connector(mgr, port, proppath); + if (!port->connector) { + ret = -ENOMEM; + goto error; + } + + if (port->pdt != DP_PEER_DEVICE_NONE && + drm_dp_mst_is_end_device(port->pdt, port->mcs) && + port->port_num >= DP_MST_LOGICAL_PORT_0) + port->cached_edid = drm_get_edid(port->connector, + &port->aux.ddc); + + drm_connector_register(port->connector); + return; + +error: + drm_err(mgr->dev, "Failed to create connector for port %p: %d\n", port, ret); +} + +/* + * Drop a topology reference, and unlink the port from the in-memory topology + * layout + */ +static void +drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port) +{ + mutex_lock(&mgr->lock); + port->parent->num_ports--; + list_del(&port->next); + mutex_unlock(&mgr->lock); + drm_dp_mst_topology_put_port(port); +} + +static struct drm_dp_mst_port * +drm_dp_mst_add_port(struct drm_device *dev, + struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_branch *mstb, u8 port_number) +{ + struct drm_dp_mst_port *port = kzalloc(sizeof(*port), GFP_KERNEL); + + if (!port) + return NULL; + + kref_init(&port->topology_kref); + kref_init(&port->malloc_kref); + port->parent = mstb; + port->port_num = port_number; + port->mgr = mgr; + port->aux.name = "DPMST"; + port->aux.dev = dev->dev; + port->aux.is_remote = true; + + /* initialize the MST downstream port's AUX crc work queue */ + port->aux.drm_dev = dev; + drm_dp_remote_aux_init(&port->aux); + + /* + * Make sure the memory allocation for our parent branch stays + * around until our own memory allocation is released + */ + drm_dp_mst_get_mstb_malloc(mstb); + + return port; +} + +static int +drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb, + struct drm_device *dev, + struct drm_dp_link_addr_reply_port *port_msg) +{ + struct drm_dp_mst_topology_mgr *mgr = mstb->mgr; + struct drm_dp_mst_port *port; + int old_ddps = 0, ret; + u8 new_pdt = DP_PEER_DEVICE_NONE; + bool new_mcs = 0; + bool created = false, send_link_addr = false, changed = false; + + port = drm_dp_get_port(mstb, port_msg->port_number); + if (!port) { + port = drm_dp_mst_add_port(dev, mgr, mstb, + port_msg->port_number); + if (!port) + return -ENOMEM; + created = true; + changed = true; + } else if (!port->input && port_msg->input_port && port->connector) { + /* Since port->connector can't be changed here, we create a + * new port if input_port changes from 0 to 1 + */ + drm_dp_mst_topology_unlink_port(mgr, port); + drm_dp_mst_topology_put_port(port); + port = drm_dp_mst_add_port(dev, mgr, mstb, + port_msg->port_number); + if (!port) + return -ENOMEM; + changed = true; + created = true; + } else if (port->input && !port_msg->input_port) { + changed = true; + } else if (port->connector) { + /* We're updating a port that's exposed to userspace, so do it + * under lock + */ + drm_modeset_lock(&mgr->base.lock, NULL); + + old_ddps = port->ddps; + changed = port->ddps != port_msg->ddps || + (port->ddps && + (port->ldps != port_msg->legacy_device_plug_status || + port->dpcd_rev != port_msg->dpcd_revision || + port->mcs != port_msg->mcs || + port->pdt != port_msg->peer_device_type || + port->num_sdp_stream_sinks != + port_msg->num_sdp_stream_sinks)); + } + + port->input = port_msg->input_port; + if (!port->input) + new_pdt = port_msg->peer_device_type; + new_mcs = port_msg->mcs; + port->ddps = port_msg->ddps; + port->ldps = port_msg->legacy_device_plug_status; + port->dpcd_rev = port_msg->dpcd_revision; + port->num_sdp_streams = port_msg->num_sdp_streams; + port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks; + + /* manage mstb port lists with mgr lock - take a reference + for this list */ + if (created) { + mutex_lock(&mgr->lock); + drm_dp_mst_topology_get_port(port); + list_add(&port->next, &mstb->ports); + mstb->num_ports++; + mutex_unlock(&mgr->lock); + } + + /* + * Reprobe PBN caps on both hotplug, and when re-probing the link + * for our parent mstb + */ + if (old_ddps != port->ddps || !created) { + if (port->ddps && !port->input) { + ret = drm_dp_send_enum_path_resources(mgr, mstb, + port); + if (ret == 1) + changed = true; + } else { + port->full_pbn = 0; + } + } + + ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs); + if (ret == 1) { + send_link_addr = true; + } else if (ret < 0) { + drm_err(dev, "Failed to change PDT on port %p: %d\n", port, ret); + goto fail; + } + + /* + * If this port wasn't just created, then we're reprobing because + * we're coming out of suspend. In this case, always resend the link + * address if there's an MSTB on this port + */ + if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING && + port->mcs) + send_link_addr = true; + + if (port->connector) + drm_modeset_unlock(&mgr->base.lock); + else if (!port->input) + drm_dp_mst_port_add_connector(mstb, port); + + if (send_link_addr && port->mstb) { + ret = drm_dp_send_link_address(mgr, port->mstb); + if (ret == 1) /* MSTB below us changed */ + changed = true; + else if (ret < 0) + goto fail_put; + } + + /* put reference to this port */ + drm_dp_mst_topology_put_port(port); + return changed; + +fail: + drm_dp_mst_topology_unlink_port(mgr, port); + if (port->connector) + drm_modeset_unlock(&mgr->base.lock); +fail_put: + drm_dp_mst_topology_put_port(port); + return ret; +} + +static int +drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb, + struct drm_dp_connection_status_notify *conn_stat) +{ + struct drm_dp_mst_topology_mgr *mgr = mstb->mgr; + struct drm_dp_mst_port *port; + int old_ddps, ret; + u8 new_pdt; + bool new_mcs; + bool dowork = false, create_connector = false; + + port = drm_dp_get_port(mstb, conn_stat->port_number); + if (!port) + return 0; + + if (port->connector) { + if (!port->input && conn_stat->input_port) { + /* + * We can't remove a connector from an already exposed + * port, so just throw the port out and make sure we + * reprobe the link address of it's parent MSTB + */ + drm_dp_mst_topology_unlink_port(mgr, port); + mstb->link_address_sent = false; + dowork = true; + goto out; + } + + /* Locking is only needed if the port's exposed to userspace */ + drm_modeset_lock(&mgr->base.lock, NULL); + } else if (port->input && !conn_stat->input_port) { + create_connector = true; + /* Reprobe link address so we get num_sdp_streams */ + mstb->link_address_sent = false; + dowork = true; + } + + old_ddps = port->ddps; + port->input = conn_stat->input_port; + port->ldps = conn_stat->legacy_device_plug_status; + port->ddps = conn_stat->displayport_device_plug_status; + + if (old_ddps != port->ddps) { + if (port->ddps && !port->input) + drm_dp_send_enum_path_resources(mgr, mstb, port); + else + port->full_pbn = 0; + } + + new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type; + new_mcs = conn_stat->message_capability_status; + ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs); + if (ret == 1) { + dowork = true; + } else if (ret < 0) { + drm_err(mgr->dev, "Failed to change PDT for port %p: %d\n", port, ret); + dowork = false; + } + + if (port->connector) + drm_modeset_unlock(&mgr->base.lock); + else if (create_connector) + drm_dp_mst_port_add_connector(mstb, port); + +out: + drm_dp_mst_topology_put_port(port); + return dowork; +} + +static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr, + u8 lct, u8 *rad) +{ + struct drm_dp_mst_branch *mstb; + struct drm_dp_mst_port *port; + int i, ret; + /* find the port by iterating down */ + + mutex_lock(&mgr->lock); + mstb = mgr->mst_primary; + + if (!mstb) + goto out; + + for (i = 0; i < lct - 1; i++) { + int shift = (i % 2) ? 0 : 4; + int port_num = (rad[i / 2] >> shift) & 0xf; + + list_for_each_entry(port, &mstb->ports, next) { + if (port->port_num == port_num) { + mstb = port->mstb; + if (!mstb) { + drm_err(mgr->dev, + "failed to lookup MSTB with lct %d, rad %02x\n", + lct, rad[0]); + goto out; + } + + break; + } + } + } + ret = drm_dp_mst_topology_try_get_mstb(mstb); + if (!ret) + mstb = NULL; +out: + mutex_unlock(&mgr->lock); + return mstb; +} + +static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper( + struct drm_dp_mst_branch *mstb, + const uint8_t *guid) +{ + struct drm_dp_mst_branch *found_mstb; + struct drm_dp_mst_port *port; + + if (!mstb) + return NULL; + + if (memcmp(mstb->guid, guid, 16) == 0) + return mstb; + + + list_for_each_entry(port, &mstb->ports, next) { + found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid); + + if (found_mstb) + return found_mstb; + } + + return NULL; +} + +static struct drm_dp_mst_branch * +drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr, + const uint8_t *guid) +{ + struct drm_dp_mst_branch *mstb; + int ret; + + /* find the port by iterating down */ + mutex_lock(&mgr->lock); + + mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid); + if (mstb) { + ret = drm_dp_mst_topology_try_get_mstb(mstb); + if (!ret) + mstb = NULL; + } + + mutex_unlock(&mgr->lock); + return mstb; +} + +static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_branch *mstb) +{ + struct drm_dp_mst_port *port; + int ret; + bool changed = false; + + if (!mstb->link_address_sent) { + ret = drm_dp_send_link_address(mgr, mstb); + if (ret == 1) + changed = true; + else if (ret < 0) + return ret; + } + + list_for_each_entry(port, &mstb->ports, next) { + if (port->input || !port->ddps || !port->mstb) + continue; + + ret = drm_dp_check_and_send_link_address(mgr, port->mstb); + if (ret == 1) + changed = true; + else if (ret < 0) + return ret; + } + + return changed; +} + +static void drm_dp_mst_link_probe_work(struct work_struct *work) +{ + struct drm_dp_mst_topology_mgr *mgr = + container_of(work, struct drm_dp_mst_topology_mgr, work); + struct drm_device *dev = mgr->dev; + struct drm_dp_mst_branch *mstb; + int ret; + bool clear_payload_id_table; + + mutex_lock(&mgr->probe_lock); + + mutex_lock(&mgr->lock); + clear_payload_id_table = !mgr->payload_id_table_cleared; + mgr->payload_id_table_cleared = true; + + mstb = mgr->mst_primary; + if (mstb) { + ret = drm_dp_mst_topology_try_get_mstb(mstb); + if (!ret) + mstb = NULL; + } + mutex_unlock(&mgr->lock); + if (!mstb) { + mutex_unlock(&mgr->probe_lock); + return; + } + + /* + * Certain branch devices seem to incorrectly report an available_pbn + * of 0 on downstream sinks, even after clearing the + * DP_PAYLOAD_ALLOCATE_* registers in + * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C + * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make + * things work again. + */ + if (clear_payload_id_table) { + drm_dbg_kms(dev, "Clearing payload ID table\n"); + drm_dp_send_clear_payload_id_table(mgr, mstb); + } + + ret = drm_dp_check_and_send_link_address(mgr, mstb); + drm_dp_mst_topology_put_mstb(mstb); + + mutex_unlock(&mgr->probe_lock); + if (ret > 0) + drm_kms_helper_hotplug_event(dev); +} + +static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr, + u8 *guid) +{ + u64 salt; + + if (memchr_inv(guid, 0, 16)) + return true; + + salt = get_jiffies_64(); + + memcpy(&guid[0], &salt, sizeof(u64)); + memcpy(&guid[8], &salt, sizeof(u64)); + + return false; +} + +static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg, + u8 port_num, u32 offset, u8 num_bytes) +{ + struct drm_dp_sideband_msg_req_body req; + + req.req_type = DP_REMOTE_DPCD_READ; + req.u.dpcd_read.port_number = port_num; + req.u.dpcd_read.dpcd_address = offset; + req.u.dpcd_read.num_bytes = num_bytes; + drm_dp_encode_sideband_req(&req, msg); +} + +static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr, + bool up, u8 *msg, int len) +{ + int ret; + int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE; + int tosend, total, offset; + int retries = 0; + +retry: + total = len; + offset = 0; + do { + tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total); + + ret = drm_dp_dpcd_write(mgr->aux, regbase + offset, + &msg[offset], + tosend); + if (ret != tosend) { + if (ret == -EIO && retries < 5) { + retries++; + goto retry; + } + drm_dbg_kms(mgr->dev, "failed to dpcd write %d %d\n", tosend, ret); + + return -EIO; + } + offset += tosend; + total -= tosend; + } while (total > 0); + return 0; +} + +static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr, + struct drm_dp_sideband_msg_tx *txmsg) +{ + struct drm_dp_mst_branch *mstb = txmsg->dst; + u8 req_type; + + req_type = txmsg->msg[0] & 0x7f; + if (req_type == DP_CONNECTION_STATUS_NOTIFY || + req_type == DP_RESOURCE_STATUS_NOTIFY || + req_type == DP_CLEAR_PAYLOAD_ID_TABLE) + hdr->broadcast = 1; + else + hdr->broadcast = 0; + hdr->path_msg = txmsg->path_msg; + if (hdr->broadcast) { + hdr->lct = 1; + hdr->lcr = 6; + } else { + hdr->lct = mstb->lct; + hdr->lcr = mstb->lct - 1; + } + + memcpy(hdr->rad, mstb->rad, hdr->lct / 2); + + return 0; +} +/* + * process a single block of the next message in the sideband queue + */ +static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_sideband_msg_tx *txmsg, + bool up) +{ + u8 chunk[48]; + struct drm_dp_sideband_msg_hdr hdr; + int len, space, idx, tosend; + int ret; + + if (txmsg->state == DRM_DP_SIDEBAND_TX_SENT) + return 0; + + memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr)); + + if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED) + txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND; + + /* make hdr from dst mst */ + ret = set_hdr_from_dst_qlock(&hdr, txmsg); + if (ret < 0) + return ret; + + /* amount left to send in this message */ + len = txmsg->cur_len - txmsg->cur_offset; + + /* 48 - sideband msg size - 1 byte for data CRC, x header bytes */ + space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr); + + tosend = min(len, space); + if (len == txmsg->cur_len) + hdr.somt = 1; + if (space >= len) + hdr.eomt = 1; + + + hdr.msg_len = tosend + 1; + drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx); + memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend); + /* add crc at end */ + drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend); + idx += tosend + 1; + + ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx); + if (ret) { + if (drm_debug_enabled(DRM_UT_DP)) { + struct drm_printer p = drm_debug_printer(DBG_PREFIX); + + drm_printf(&p, "sideband msg failed to send\n"); + drm_dp_mst_dump_sideband_msg_tx(&p, txmsg); + } + return ret; + } + + txmsg->cur_offset += tosend; + if (txmsg->cur_offset == txmsg->cur_len) { + txmsg->state = DRM_DP_SIDEBAND_TX_SENT; + return 1; + } + return 0; +} + +static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr) +{ + struct drm_dp_sideband_msg_tx *txmsg; + int ret; + + WARN_ON(!mutex_is_locked(&mgr->qlock)); + + /* construct a chunk from the first msg in the tx_msg queue */ + if (list_empty(&mgr->tx_msg_downq)) + return; + + txmsg = list_first_entry(&mgr->tx_msg_downq, + struct drm_dp_sideband_msg_tx, next); + ret = process_single_tx_qlock(mgr, txmsg, false); + if (ret < 0) { + drm_dbg_kms(mgr->dev, "failed to send msg in q %d\n", ret); + list_del(&txmsg->next); + txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT; + wake_up_all(&mgr->tx_waitq); + } +} + +static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_sideband_msg_tx *txmsg) +{ + mutex_lock(&mgr->qlock); + list_add_tail(&txmsg->next, &mgr->tx_msg_downq); + + if (drm_debug_enabled(DRM_UT_DP)) { + struct drm_printer p = drm_debug_printer(DBG_PREFIX); + + drm_dp_mst_dump_sideband_msg_tx(&p, txmsg); + } + + if (list_is_singular(&mgr->tx_msg_downq)) + process_single_down_tx_qlock(mgr); + mutex_unlock(&mgr->qlock); +} + +static void +drm_dp_dump_link_address(const struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_link_address_ack_reply *reply) +{ + struct drm_dp_link_addr_reply_port *port_reply; + int i; + + for (i = 0; i < reply->nports; i++) { + port_reply = &reply->ports[i]; + drm_dbg_kms(mgr->dev, + "port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n", + i, + port_reply->input_port, + port_reply->peer_device_type, + port_reply->port_number, + port_reply->dpcd_revision, + port_reply->mcs, + port_reply->ddps, + port_reply->legacy_device_plug_status, + port_reply->num_sdp_streams, + port_reply->num_sdp_stream_sinks); + } +} + +static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_branch *mstb) +{ + struct drm_dp_sideband_msg_tx *txmsg; + struct drm_dp_link_address_ack_reply *reply; + struct drm_dp_mst_port *port, *tmp; + int i, ret, port_mask = 0; + bool changed = false; + + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL); + if (!txmsg) + return -ENOMEM; + + txmsg->dst = mstb; + build_link_address(txmsg); + + mstb->link_address_sent = true; + drm_dp_queue_down_tx(mgr, txmsg); + + /* FIXME: Actually do some real error handling here */ + ret = drm_dp_mst_wait_tx_reply(mstb, txmsg); + if (ret <= 0) { + drm_err(mgr->dev, "Sending link address failed with %d\n", ret); + goto out; + } + if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) { + drm_err(mgr->dev, "link address NAK received\n"); + ret = -EIO; + goto out; + } + + reply = &txmsg->reply.u.link_addr; + drm_dbg_kms(mgr->dev, "link address reply: %d\n", reply->nports); + drm_dp_dump_link_address(mgr, reply); + + ret = drm_dp_check_mstb_guid(mstb, reply->guid); + if (ret) { + char buf[64]; + + drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, buf, sizeof(buf)); + drm_err(mgr->dev, "GUID check on %s failed: %d\n", buf, ret); + goto out; + } + + for (i = 0; i < reply->nports; i++) { + port_mask |= BIT(reply->ports[i].port_number); + ret = drm_dp_mst_handle_link_address_port(mstb, mgr->dev, + &reply->ports[i]); + if (ret == 1) + changed = true; + else if (ret < 0) + goto out; + } + + /* Prune any ports that are currently a part of mstb in our in-memory + * topology, but were not seen in this link address. Usually this + * means that they were removed while the topology was out of sync, + * e.g. during suspend/resume + */ + mutex_lock(&mgr->lock); + list_for_each_entry_safe(port, tmp, &mstb->ports, next) { + if (port_mask & BIT(port->port_num)) + continue; + + drm_dbg_kms(mgr->dev, "port %d was not in link address, removing\n", + port->port_num); + list_del(&port->next); + drm_dp_mst_topology_put_port(port); + changed = true; + } + mutex_unlock(&mgr->lock); + +out: + if (ret <= 0) + mstb->link_address_sent = false; + kfree(txmsg); + return ret < 0 ? ret : changed; +} + +static void +drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_branch *mstb) +{ + struct drm_dp_sideband_msg_tx *txmsg; + int ret; + + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL); + if (!txmsg) + return; + + txmsg->dst = mstb; + build_clear_payload_id_table(txmsg); + + drm_dp_queue_down_tx(mgr, txmsg); + + ret = drm_dp_mst_wait_tx_reply(mstb, txmsg); + if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) + drm_dbg_kms(mgr->dev, "clear payload table id nak received\n"); + + kfree(txmsg); +} + +static int +drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_branch *mstb, + struct drm_dp_mst_port *port) +{ + struct drm_dp_enum_path_resources_ack_reply *path_res; + struct drm_dp_sideband_msg_tx *txmsg; + int ret; + + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL); + if (!txmsg) + return -ENOMEM; + + txmsg->dst = mstb; + build_enum_path_resources(txmsg, port->port_num); + + drm_dp_queue_down_tx(mgr, txmsg); + + ret = drm_dp_mst_wait_tx_reply(mstb, txmsg); + if (ret > 0) { + ret = 0; + path_res = &txmsg->reply.u.path_resources; + + if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) { + drm_dbg_kms(mgr->dev, "enum path resources nak received\n"); + } else { + if (port->port_num != path_res->port_number) + DRM_ERROR("got incorrect port in response\n"); + + drm_dbg_kms(mgr->dev, "enum path resources %d: %d %d\n", + path_res->port_number, + path_res->full_payload_bw_number, + path_res->avail_payload_bw_number); + + /* + * If something changed, make sure we send a + * hotplug + */ + if (port->full_pbn != path_res->full_payload_bw_number || + port->fec_capable != path_res->fec_capable) + ret = 1; + + port->full_pbn = path_res->full_payload_bw_number; + port->fec_capable = path_res->fec_capable; + } + } + + kfree(txmsg); + return ret; +} + +static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb) +{ + if (!mstb->port_parent) + return NULL; + + if (mstb->port_parent->mstb != mstb) + return mstb->port_parent; + + return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent); +} + +/* + * Searches upwards in the topology starting from mstb to try to find the + * closest available parent of mstb that's still connected to the rest of the + * topology. This can be used in order to perform operations like releasing + * payloads, where the branch device which owned the payload may no longer be + * around and thus would require that the payload on the last living relative + * be freed instead. + */ +static struct drm_dp_mst_branch * +drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_branch *mstb, + int *port_num) +{ + struct drm_dp_mst_branch *rmstb = NULL; + struct drm_dp_mst_port *found_port; + + mutex_lock(&mgr->lock); + if (!mgr->mst_primary) + goto out; + + do { + found_port = drm_dp_get_last_connected_port_to_mstb(mstb); + if (!found_port) + break; + + if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) { + rmstb = found_port->parent; + *port_num = found_port->port_num; + } else { + /* Search again, starting from this parent */ + mstb = found_port->parent; + } + } while (!rmstb); +out: + mutex_unlock(&mgr->lock); + return rmstb; +} + +static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port, + int id, + int pbn) +{ + struct drm_dp_sideband_msg_tx *txmsg; + struct drm_dp_mst_branch *mstb; + int ret, port_num; + u8 sinks[DRM_DP_MAX_SDP_STREAMS]; + int i; + + port_num = port->port_num; + mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent); + if (!mstb) { + mstb = drm_dp_get_last_connected_port_and_mstb(mgr, + port->parent, + &port_num); + + if (!mstb) + return -EINVAL; + } + + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL); + if (!txmsg) { + ret = -ENOMEM; + goto fail_put; + } + + for (i = 0; i < port->num_sdp_streams; i++) + sinks[i] = i; + + txmsg->dst = mstb; + build_allocate_payload(txmsg, port_num, + id, + pbn, port->num_sdp_streams, sinks); + + drm_dp_queue_down_tx(mgr, txmsg); + + /* + * FIXME: there is a small chance that between getting the last + * connected mstb and sending the payload message, the last connected + * mstb could also be removed from the topology. In the future, this + * needs to be fixed by restarting the + * drm_dp_get_last_connected_port_and_mstb() search in the event of a + * timeout if the topology is still connected to the system. + */ + ret = drm_dp_mst_wait_tx_reply(mstb, txmsg); + if (ret > 0) { + if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) + ret = -EINVAL; + else + ret = 0; + } + kfree(txmsg); +fail_put: + drm_dp_mst_topology_put_mstb(mstb); + return ret; +} + +int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port, bool power_up) +{ + struct drm_dp_sideband_msg_tx *txmsg; + int ret; + + port = drm_dp_mst_topology_get_port_validated(mgr, port); + if (!port) + return -EINVAL; + + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL); + if (!txmsg) { + drm_dp_mst_topology_put_port(port); + return -ENOMEM; + } + + txmsg->dst = port->parent; + build_power_updown_phy(txmsg, port->port_num, power_up); + drm_dp_queue_down_tx(mgr, txmsg); + + ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg); + if (ret > 0) { + if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) + ret = -EINVAL; + else + ret = 0; + } + kfree(txmsg); + drm_dp_mst_topology_put_port(port); + + return ret; +} +EXPORT_SYMBOL(drm_dp_send_power_updown_phy); + +int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port, + struct drm_dp_query_stream_enc_status_ack_reply *status) +{ + struct drm_dp_mst_topology_state *state; + struct drm_dp_mst_atomic_payload *payload; + struct drm_dp_sideband_msg_tx *txmsg; + u8 nonce[7]; + int ret; + + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL); + if (!txmsg) + return -ENOMEM; + + port = drm_dp_mst_topology_get_port_validated(mgr, port); + if (!port) { + ret = -EINVAL; + goto out_get_port; + } + + get_random_bytes(nonce, sizeof(nonce)); + + drm_modeset_lock(&mgr->base.lock, NULL); + state = to_drm_dp_mst_topology_state(mgr->base.state); + payload = drm_atomic_get_mst_payload_state(state, port); + + /* + * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS message + * transaction at the MST Branch device directly connected to the + * Source" + */ + txmsg->dst = mgr->mst_primary; + + build_query_stream_enc_status(txmsg, payload->vcpi, nonce); + + drm_dp_queue_down_tx(mgr, txmsg); + + ret = drm_dp_mst_wait_tx_reply(mgr->mst_primary, txmsg); + if (ret < 0) { + goto out; + } else if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) { + drm_dbg_kms(mgr->dev, "query encryption status nak received\n"); + ret = -ENXIO; + goto out; + } + + ret = 0; + memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status)); + +out: + drm_modeset_unlock(&mgr->base.lock); + drm_dp_mst_topology_put_port(port); +out_get_port: + kfree(txmsg); + return ret; +} +EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status); + +static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_atomic_payload *payload) +{ + return drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload->vc_start_slot, + payload->time_slots); +} + +static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_atomic_payload *payload) +{ + int ret; + struct drm_dp_mst_port *port = drm_dp_mst_topology_get_port_validated(mgr, payload->port); + + if (!port) + return -EIO; + + ret = drm_dp_payload_send_msg(mgr, port, payload->vcpi, payload->pbn); + drm_dp_mst_topology_put_port(port); + return ret; +} + +static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_topology_state *mst_state, + struct drm_dp_mst_atomic_payload *payload) +{ + drm_dbg_kms(mgr->dev, "\n"); + + /* it's okay for these to fail */ + drm_dp_payload_send_msg(mgr, payload->port, payload->vcpi, 0); + drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload->vc_start_slot, 0); + + return 0; +} + +/** + * drm_dp_add_payload_part1() - Execute payload update part 1 + * @mgr: Manager to use. + * @mst_state: The MST atomic state + * @payload: The payload to write + * + * Determines the starting time slot for the given payload, and programs the VCPI for this payload + * into hardware. After calling this, the driver should generate ACT and payload packets. + * + * Returns: 0 on success, error code on failure. In the event that this fails, + * @payload.vc_start_slot will also be set to -1. + */ +int drm_dp_add_payload_part1(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_topology_state *mst_state, + struct drm_dp_mst_atomic_payload *payload) +{ + struct drm_dp_mst_port *port; + int ret; + + port = drm_dp_mst_topology_get_port_validated(mgr, payload->port); + if (!port) { + drm_dbg_kms(mgr->dev, + "VCPI %d for port %p not in topology, not creating a payload\n", + payload->vcpi, payload->port); + payload->vc_start_slot = -1; + return 0; + } + + if (mgr->payload_count == 0) + mgr->next_start_slot = mst_state->start_slot; + + payload->vc_start_slot = mgr->next_start_slot; + + ret = drm_dp_create_payload_step1(mgr, payload); + drm_dp_mst_topology_put_port(port); + if (ret < 0) { + drm_warn(mgr->dev, "Failed to create MST payload for port %p: %d\n", + payload->port, ret); + payload->vc_start_slot = -1; + return ret; + } + + mgr->payload_count++; + mgr->next_start_slot += payload->time_slots; + + return 0; +} +EXPORT_SYMBOL(drm_dp_add_payload_part1); + +/** + * drm_dp_remove_payload() - Remove an MST payload + * @mgr: Manager to use. + * @mst_state: The MST atomic state + * @old_payload: The payload with its old state + * @new_payload: The payload to write + * + * Removes a payload from an MST topology if it was successfully assigned a start slot. Also updates + * the starting time slots of all other payloads which would have been shifted towards the start of + * the VC table as a result. After calling this, the driver should generate ACT and payload packets. + */ +void drm_dp_remove_payload(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_topology_state *mst_state, + const struct drm_dp_mst_atomic_payload *old_payload, + struct drm_dp_mst_atomic_payload *new_payload) +{ + struct drm_dp_mst_atomic_payload *pos; + bool send_remove = false; + + /* We failed to make the payload, so nothing to do */ + if (new_payload->vc_start_slot == -1) + return; + + mutex_lock(&mgr->lock); + send_remove = drm_dp_mst_port_downstream_of_branch(new_payload->port, mgr->mst_primary); + mutex_unlock(&mgr->lock); + + if (send_remove) + drm_dp_destroy_payload_step1(mgr, mst_state, new_payload); + else + drm_dbg_kms(mgr->dev, "Payload for VCPI %d not in topology, not sending remove\n", + new_payload->vcpi); + + list_for_each_entry(pos, &mst_state->payloads, next) { + if (pos != new_payload && pos->vc_start_slot > new_payload->vc_start_slot) + pos->vc_start_slot -= old_payload->time_slots; + } + new_payload->vc_start_slot = -1; + + mgr->payload_count--; + mgr->next_start_slot -= old_payload->time_slots; + + if (new_payload->delete) + drm_dp_mst_put_port_malloc(new_payload->port); +} +EXPORT_SYMBOL(drm_dp_remove_payload); + +/** + * drm_dp_add_payload_part2() - Execute payload update part 2 + * @mgr: Manager to use. + * @state: The global atomic state + * @payload: The payload to update + * + * If @payload was successfully assigned a starting time slot by drm_dp_add_payload_part1(), this + * function will send the sideband messages to finish allocating this payload. + * + * Returns: 0 on success, negative error code on failure. + */ +int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr, + struct drm_atomic_state *state, + struct drm_dp_mst_atomic_payload *payload) +{ + int ret = 0; + + /* Skip failed payloads */ + if (payload->vc_start_slot == -1) { + drm_dbg_kms(mgr->dev, "Part 1 of payload creation for %s failed, skipping part 2\n", + payload->port->connector->name); + return -EIO; + } + + ret = drm_dp_create_payload_step2(mgr, payload); + if (ret < 0) { + if (!payload->delete) + drm_err(mgr->dev, "Step 2 of creating MST payload for %p failed: %d\n", + payload->port, ret); + else + drm_dbg_kms(mgr->dev, "Step 2 of removing MST payload for %p failed: %d\n", + payload->port, ret); + } + + return ret; +} +EXPORT_SYMBOL(drm_dp_add_payload_part2); + +static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port, + int offset, int size, u8 *bytes) +{ + int ret = 0; + struct drm_dp_sideband_msg_tx *txmsg; + struct drm_dp_mst_branch *mstb; + + mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent); + if (!mstb) + return -EINVAL; + + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL); + if (!txmsg) { + ret = -ENOMEM; + goto fail_put; + } + + build_dpcd_read(txmsg, port->port_num, offset, size); + txmsg->dst = port->parent; + + drm_dp_queue_down_tx(mgr, txmsg); + + ret = drm_dp_mst_wait_tx_reply(mstb, txmsg); + if (ret < 0) + goto fail_free; + + if (txmsg->reply.reply_type == 1) { + drm_dbg_kms(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n", + mstb, port->port_num, offset, size); + ret = -EIO; + goto fail_free; + } + + if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) { + ret = -EPROTO; + goto fail_free; + } + + ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes, + size); + memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret); + +fail_free: + kfree(txmsg); +fail_put: + drm_dp_mst_topology_put_mstb(mstb); + + return ret; +} + +static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port, + int offset, int size, u8 *bytes) +{ + int ret; + struct drm_dp_sideband_msg_tx *txmsg; + struct drm_dp_mst_branch *mstb; + + mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent); + if (!mstb) + return -EINVAL; + + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL); + if (!txmsg) { + ret = -ENOMEM; + goto fail_put; + } + + build_dpcd_write(txmsg, port->port_num, offset, size, bytes); + txmsg->dst = mstb; + + drm_dp_queue_down_tx(mgr, txmsg); + + ret = drm_dp_mst_wait_tx_reply(mstb, txmsg); + if (ret > 0) { + if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) + ret = -EIO; + else + ret = size; + } + + kfree(txmsg); +fail_put: + drm_dp_mst_topology_put_mstb(mstb); + return ret; +} + +static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type) +{ + struct drm_dp_sideband_msg_reply_body reply; + + reply.reply_type = DP_SIDEBAND_REPLY_ACK; + reply.req_type = req_type; + drm_dp_encode_sideband_reply(&reply, msg); + return 0; +} + +static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_branch *mstb, + int req_type, bool broadcast) +{ + struct drm_dp_sideband_msg_tx *txmsg; + + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL); + if (!txmsg) + return -ENOMEM; + + txmsg->dst = mstb; + drm_dp_encode_up_ack_reply(txmsg, req_type); + + mutex_lock(&mgr->qlock); + /* construct a chunk from the first msg in the tx_msg queue */ + process_single_tx_qlock(mgr, txmsg, true); + mutex_unlock(&mgr->qlock); + + kfree(txmsg); + return 0; +} + +/** + * drm_dp_get_vc_payload_bw - get the VC payload BW for an MST link + * @mgr: The &drm_dp_mst_topology_mgr to use + * @link_rate: link rate in 10kbits/s units + * @link_lane_count: lane count + * + * Calculate the total bandwidth of a MultiStream Transport link. The returned + * value is in units of PBNs/(timeslots/1 MTP). This value can be used to + * convert the number of PBNs required for a given stream to the number of + * timeslots this stream requires in each MTP. + */ +int drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr, + int link_rate, int link_lane_count) +{ + if (link_rate == 0 || link_lane_count == 0) + drm_dbg_kms(mgr->dev, "invalid link rate/lane count: (%d / %d)\n", + link_rate, link_lane_count); + + /* See DP v2.0 2.6.4.2, VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */ + return link_rate * link_lane_count / 54000; +} +EXPORT_SYMBOL(drm_dp_get_vc_payload_bw); + +/** + * drm_dp_read_mst_cap() - check whether or not a sink supports MST + * @aux: The DP AUX channel to use + * @dpcd: A cached copy of the DPCD capabilities for this sink + * + * Returns: %True if the sink supports MST, %false otherwise + */ +bool drm_dp_read_mst_cap(struct drm_dp_aux *aux, + const u8 dpcd[DP_RECEIVER_CAP_SIZE]) +{ + u8 mstm_cap; + + if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12) + return false; + + if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1) + return false; + + return mstm_cap & DP_MST_CAP; +} +EXPORT_SYMBOL(drm_dp_read_mst_cap); + +/** + * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager + * @mgr: manager to set state for + * @mst_state: true to enable MST on this connector - false to disable. + * + * This is called by the driver when it detects an MST capable device plugged + * into a DP MST capable port, or when a DP MST capable device is unplugged. + */ +int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state) +{ + int ret = 0; + struct drm_dp_mst_branch *mstb = NULL; + + mutex_lock(&mgr->lock); + if (mst_state == mgr->mst_state) + goto out_unlock; + + mgr->mst_state = mst_state; + /* set the device into MST mode */ + if (mst_state) { + WARN_ON(mgr->mst_primary); + + /* get dpcd info */ + ret = drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd); + if (ret < 0) { + drm_dbg_kms(mgr->dev, "%s: failed to read DPCD, ret %d\n", + mgr->aux->name, ret); + goto out_unlock; + } + + /* add initial branch device at LCT 1 */ + mstb = drm_dp_add_mst_branch_device(1, NULL); + if (mstb == NULL) { + ret = -ENOMEM; + goto out_unlock; + } + mstb->mgr = mgr; + + /* give this the main reference */ + mgr->mst_primary = mstb; + drm_dp_mst_topology_get_mstb(mgr->mst_primary); + + ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, + DP_MST_EN | + DP_UP_REQ_EN | + DP_UPSTREAM_IS_SRC); + if (ret < 0) + goto out_unlock; + + /* Write reset payload */ + drm_dp_dpcd_write_payload(mgr, 0, 0, 0x3f); + + queue_work(system_long_wq, &mgr->work); + + ret = 0; + } else { + /* disable MST on the device */ + mstb = mgr->mst_primary; + mgr->mst_primary = NULL; + /* this can fail if the device is gone */ + drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0); + ret = 0; + mgr->payload_id_table_cleared = false; + + memset(&mgr->down_rep_recv, 0, sizeof(mgr->down_rep_recv)); + memset(&mgr->up_req_recv, 0, sizeof(mgr->up_req_recv)); + } + +out_unlock: + mutex_unlock(&mgr->lock); + if (mstb) + drm_dp_mst_topology_put_mstb(mstb); + return ret; + +} +EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst); + +static void +drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb) +{ + struct drm_dp_mst_port *port; + + /* The link address will need to be re-sent on resume */ + mstb->link_address_sent = false; + + list_for_each_entry(port, &mstb->ports, next) + if (port->mstb) + drm_dp_mst_topology_mgr_invalidate_mstb(port->mstb); +} + +/** + * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager + * @mgr: manager to suspend + * + * This function tells the MST device that we can't handle UP messages + * anymore. This should stop it from sending any since we are suspended. + */ +void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr) +{ + mutex_lock(&mgr->lock); + drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, + DP_MST_EN | DP_UPSTREAM_IS_SRC); + mutex_unlock(&mgr->lock); + flush_work(&mgr->up_req_work); + flush_work(&mgr->work); + flush_work(&mgr->delayed_destroy_work); + + mutex_lock(&mgr->lock); + if (mgr->mst_state && mgr->mst_primary) + drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary); + mutex_unlock(&mgr->lock); +} +EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend); + +/** + * drm_dp_mst_topology_mgr_resume() - resume the MST manager + * @mgr: manager to resume + * @sync: whether or not to perform topology reprobing synchronously + * + * This will fetch DPCD and see if the device is still there, + * if it is, it will rewrite the MSTM control bits, and return. + * + * If the device fails this returns -1, and the driver should do + * a full MST reprobe, in case we were undocked. + * + * During system resume (where it is assumed that the driver will be calling + * drm_atomic_helper_resume()) this function should be called beforehand with + * @sync set to true. In contexts like runtime resume where the driver is not + * expected to be calling drm_atomic_helper_resume(), this function should be + * called with @sync set to false in order to avoid deadlocking. + * + * Returns: -1 if the MST topology was removed while we were suspended, 0 + * otherwise. + */ +int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr, + bool sync) +{ + int ret; + u8 guid[16]; + + mutex_lock(&mgr->lock); + if (!mgr->mst_primary) + goto out_fail; + + if (drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd) < 0) { + drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n"); + goto out_fail; + } + + ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, + DP_MST_EN | + DP_UP_REQ_EN | + DP_UPSTREAM_IS_SRC); + if (ret < 0) { + drm_dbg_kms(mgr->dev, "mst write failed - undocked during suspend?\n"); + goto out_fail; + } + + /* Some hubs forget their guids after they resume */ + ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16); + if (ret != 16) { + drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n"); + goto out_fail; + } + + ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid); + if (ret) { + drm_dbg_kms(mgr->dev, "check mstb failed - undocked during suspend?\n"); + goto out_fail; + } + + /* + * For the final step of resuming the topology, we need to bring the + * state of our in-memory topology back into sync with reality. So, + * restart the probing process as if we're probing a new hub + */ + queue_work(system_long_wq, &mgr->work); + mutex_unlock(&mgr->lock); + + if (sync) { + drm_dbg_kms(mgr->dev, + "Waiting for link probe work to finish re-syncing topology...\n"); + flush_work(&mgr->work); + } + + return 0; + +out_fail: + mutex_unlock(&mgr->lock); + return -1; +} +EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume); + +static bool +drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up, + struct drm_dp_mst_branch **mstb) +{ + int len; + u8 replyblock[32]; + int replylen, curreply; + int ret; + u8 hdrlen; + struct drm_dp_sideband_msg_hdr hdr; + struct drm_dp_sideband_msg_rx *msg = + up ? &mgr->up_req_recv : &mgr->down_rep_recv; + int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE : + DP_SIDEBAND_MSG_DOWN_REP_BASE; + + if (!up) + *mstb = NULL; + + len = min(mgr->max_dpcd_transaction_bytes, 16); + ret = drm_dp_dpcd_read(mgr->aux, basereg, replyblock, len); + if (ret != len) { + drm_dbg_kms(mgr->dev, "failed to read DPCD down rep %d %d\n", len, ret); + return false; + } + + ret = drm_dp_decode_sideband_msg_hdr(mgr, &hdr, replyblock, len, &hdrlen); + if (ret == false) { + print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16, + 1, replyblock, len, false); + drm_dbg_kms(mgr->dev, "ERROR: failed header\n"); + return false; + } + + if (!up) { + /* Caller is responsible for giving back this reference */ + *mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad); + if (!*mstb) { + drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr.lct); + return false; + } + } + + if (!drm_dp_sideband_msg_set_header(msg, &hdr, hdrlen)) { + drm_dbg_kms(mgr->dev, "sideband msg set header failed %d\n", replyblock[0]); + return false; + } + + replylen = min(msg->curchunk_len, (u8)(len - hdrlen)); + ret = drm_dp_sideband_append_payload(msg, replyblock + hdrlen, replylen); + if (!ret) { + drm_dbg_kms(mgr->dev, "sideband msg build failed %d\n", replyblock[0]); + return false; + } + + replylen = msg->curchunk_len + msg->curchunk_hdrlen - len; + curreply = len; + while (replylen > 0) { + len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16); + ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply, + replyblock, len); + if (ret != len) { + drm_dbg_kms(mgr->dev, "failed to read a chunk (len %d, ret %d)\n", + len, ret); + return false; + } + + ret = drm_dp_sideband_append_payload(msg, replyblock, len); + if (!ret) { + drm_dbg_kms(mgr->dev, "failed to build sideband msg\n"); + return false; + } + + curreply += len; + replylen -= len; + } + return true; +} + +static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr) +{ + struct drm_dp_sideband_msg_tx *txmsg; + struct drm_dp_mst_branch *mstb = NULL; + struct drm_dp_sideband_msg_rx *msg = &mgr->down_rep_recv; + + if (!drm_dp_get_one_sb_msg(mgr, false, &mstb)) + goto out_clear_reply; + + /* Multi-packet message transmission, don't clear the reply */ + if (!msg->have_eomt) + goto out; + + /* find the message */ + mutex_lock(&mgr->qlock); + txmsg = list_first_entry_or_null(&mgr->tx_msg_downq, + struct drm_dp_sideband_msg_tx, next); + mutex_unlock(&mgr->qlock); + + /* Were we actually expecting a response, and from this mstb? */ + if (!txmsg || txmsg->dst != mstb) { + struct drm_dp_sideband_msg_hdr *hdr; + + hdr = &msg->initial_hdr; + drm_dbg_kms(mgr->dev, "Got MST reply with no msg %p %d %d %02x %02x\n", + mstb, hdr->seqno, hdr->lct, hdr->rad[0], msg->msg[0]); + goto out_clear_reply; + } + + drm_dp_sideband_parse_reply(mgr, msg, &txmsg->reply); + + if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) { + drm_dbg_kms(mgr->dev, + "Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n", + txmsg->reply.req_type, + drm_dp_mst_req_type_str(txmsg->reply.req_type), + txmsg->reply.u.nak.reason, + drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason), + txmsg->reply.u.nak.nak_data); + } + + memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx)); + drm_dp_mst_topology_put_mstb(mstb); + + mutex_lock(&mgr->qlock); + txmsg->state = DRM_DP_SIDEBAND_TX_RX; + list_del(&txmsg->next); + mutex_unlock(&mgr->qlock); + + wake_up_all(&mgr->tx_waitq); + + return 0; + +out_clear_reply: + memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx)); +out: + if (mstb) + drm_dp_mst_topology_put_mstb(mstb); + + return 0; +} + +static inline bool +drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_pending_up_req *up_req) +{ + struct drm_dp_mst_branch *mstb = NULL; + struct drm_dp_sideband_msg_req_body *msg = &up_req->msg; + struct drm_dp_sideband_msg_hdr *hdr = &up_req->hdr; + bool hotplug = false, dowork = false; + + if (hdr->broadcast) { + const u8 *guid = NULL; + + if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) + guid = msg->u.conn_stat.guid; + else if (msg->req_type == DP_RESOURCE_STATUS_NOTIFY) + guid = msg->u.resource_stat.guid; + + if (guid) + mstb = drm_dp_get_mst_branch_device_by_guid(mgr, guid); + } else { + mstb = drm_dp_get_mst_branch_device(mgr, hdr->lct, hdr->rad); + } + + if (!mstb) { + drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr->lct); + return false; + } + + /* TODO: Add missing handler for DP_RESOURCE_STATUS_NOTIFY events */ + if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) { + dowork = drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat); + hotplug = true; + } + + drm_dp_mst_topology_put_mstb(mstb); + + if (dowork) + queue_work(system_long_wq, &mgr->work); + return hotplug; +} + +static void drm_dp_mst_up_req_work(struct work_struct *work) +{ + struct drm_dp_mst_topology_mgr *mgr = + container_of(work, struct drm_dp_mst_topology_mgr, + up_req_work); + struct drm_dp_pending_up_req *up_req; + bool send_hotplug = false; + + mutex_lock(&mgr->probe_lock); + while (true) { + mutex_lock(&mgr->up_req_lock); + up_req = list_first_entry_or_null(&mgr->up_req_list, + struct drm_dp_pending_up_req, + next); + if (up_req) + list_del(&up_req->next); + mutex_unlock(&mgr->up_req_lock); + + if (!up_req) + break; + + send_hotplug |= drm_dp_mst_process_up_req(mgr, up_req); + kfree(up_req); + } + mutex_unlock(&mgr->probe_lock); + + if (send_hotplug) + drm_kms_helper_hotplug_event(mgr->dev); +} + +static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr) +{ + struct drm_dp_pending_up_req *up_req; + + if (!drm_dp_get_one_sb_msg(mgr, true, NULL)) + goto out; + + if (!mgr->up_req_recv.have_eomt) + return 0; + + up_req = kzalloc(sizeof(*up_req), GFP_KERNEL); + if (!up_req) + return -ENOMEM; + + INIT_LIST_HEAD(&up_req->next); + + drm_dp_sideband_parse_req(mgr, &mgr->up_req_recv, &up_req->msg); + + if (up_req->msg.req_type != DP_CONNECTION_STATUS_NOTIFY && + up_req->msg.req_type != DP_RESOURCE_STATUS_NOTIFY) { + drm_dbg_kms(mgr->dev, "Received unknown up req type, ignoring: %x\n", + up_req->msg.req_type); + kfree(up_req); + goto out; + } + + drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type, + false); + + if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) { + const struct drm_dp_connection_status_notify *conn_stat = + &up_req->msg.u.conn_stat; + + drm_dbg_kms(mgr->dev, "Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n", + conn_stat->port_number, + conn_stat->legacy_device_plug_status, + conn_stat->displayport_device_plug_status, + conn_stat->message_capability_status, + conn_stat->input_port, + conn_stat->peer_device_type); + } else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) { + const struct drm_dp_resource_status_notify *res_stat = + &up_req->msg.u.resource_stat; + + drm_dbg_kms(mgr->dev, "Got RSN: pn: %d avail_pbn %d\n", + res_stat->port_number, + res_stat->available_pbn); + } + + up_req->hdr = mgr->up_req_recv.initial_hdr; + mutex_lock(&mgr->up_req_lock); + list_add_tail(&up_req->next, &mgr->up_req_list); + mutex_unlock(&mgr->up_req_lock); + queue_work(system_long_wq, &mgr->up_req_work); + +out: + memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx)); + return 0; +} + +/** + * drm_dp_mst_hpd_irq_handle_event() - MST hotplug IRQ handle MST event + * @mgr: manager to notify irq for. + * @esi: 4 bytes from SINK_COUNT_ESI + * @ack: 4 bytes used to ack events starting from SINK_COUNT_ESI + * @handled: whether the hpd interrupt was consumed or not + * + * This should be called from the driver when it detects a HPD IRQ, + * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The + * topology manager will process the sideband messages received + * as indicated in the DEVICE_SERVICE_IRQ_VECTOR_ESI0 and set the + * corresponding flags that Driver has to ack the DP receiver later. + * + * Note that driver shall also call + * drm_dp_mst_hpd_irq_send_new_request() if the 'handled' is set + * after calling this function, to try to kick off a new request in + * the queue if the previous message transaction is completed. + * + * See also: + * drm_dp_mst_hpd_irq_send_new_request() + */ +int drm_dp_mst_hpd_irq_handle_event(struct drm_dp_mst_topology_mgr *mgr, const u8 *esi, + u8 *ack, bool *handled) +{ + int ret = 0; + int sc; + *handled = false; + sc = DP_GET_SINK_COUNT(esi[0]); + + if (sc != mgr->sink_count) { + mgr->sink_count = sc; + *handled = true; + } + + if (esi[1] & DP_DOWN_REP_MSG_RDY) { + ret = drm_dp_mst_handle_down_rep(mgr); + *handled = true; + ack[1] |= DP_DOWN_REP_MSG_RDY; + } + + if (esi[1] & DP_UP_REQ_MSG_RDY) { + ret |= drm_dp_mst_handle_up_req(mgr); + *handled = true; + ack[1] |= DP_UP_REQ_MSG_RDY; + } + + return ret; +} +EXPORT_SYMBOL(drm_dp_mst_hpd_irq_handle_event); + +/** + * drm_dp_mst_hpd_irq_send_new_request() - MST hotplug IRQ kick off new request + * @mgr: manager to notify irq for. + * + * This should be called from the driver when mst irq event is handled + * and acked. Note that new down request should only be sent when + * previous message transaction is completed. Source is not supposed to generate + * interleaved message transactions. + */ +void drm_dp_mst_hpd_irq_send_new_request(struct drm_dp_mst_topology_mgr *mgr) +{ + struct drm_dp_sideband_msg_tx *txmsg; + bool kick = true; + + mutex_lock(&mgr->qlock); + txmsg = list_first_entry_or_null(&mgr->tx_msg_downq, + struct drm_dp_sideband_msg_tx, next); + /* If last transaction is not completed yet*/ + if (!txmsg || + txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND || + txmsg->state == DRM_DP_SIDEBAND_TX_SENT) + kick = false; + mutex_unlock(&mgr->qlock); + + if (kick) + drm_dp_mst_kick_tx(mgr); +} +EXPORT_SYMBOL(drm_dp_mst_hpd_irq_send_new_request); +/** + * drm_dp_mst_detect_port() - get connection status for an MST port + * @connector: DRM connector for this port + * @ctx: The acquisition context to use for grabbing locks + * @mgr: manager for this port + * @port: pointer to a port + * + * This returns the current connection state for a port. + */ +int +drm_dp_mst_detect_port(struct drm_connector *connector, + struct drm_modeset_acquire_ctx *ctx, + struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port) +{ + int ret; + + /* we need to search for the port in the mgr in case it's gone */ + port = drm_dp_mst_topology_get_port_validated(mgr, port); + if (!port) + return connector_status_disconnected; + + ret = drm_modeset_lock(&mgr->base.lock, ctx); + if (ret) + goto out; + + ret = connector_status_disconnected; + + if (!port->ddps) + goto out; + + switch (port->pdt) { + case DP_PEER_DEVICE_NONE: + break; + case DP_PEER_DEVICE_MST_BRANCHING: + if (!port->mcs) + ret = connector_status_connected; + break; + + case DP_PEER_DEVICE_SST_SINK: + ret = connector_status_connected; + /* for logical ports - cache the EDID */ + if (port->port_num >= DP_MST_LOGICAL_PORT_0 && !port->cached_edid) + port->cached_edid = drm_get_edid(connector, &port->aux.ddc); + break; + case DP_PEER_DEVICE_DP_LEGACY_CONV: + if (port->ldps) + ret = connector_status_connected; + break; + } +out: + drm_dp_mst_topology_put_port(port); + return ret; +} +EXPORT_SYMBOL(drm_dp_mst_detect_port); + +/** + * drm_dp_mst_get_edid() - get EDID for an MST port + * @connector: toplevel connector to get EDID for + * @mgr: manager for this port + * @port: unverified pointer to a port. + * + * This returns an EDID for the port connected to a connector, + * It validates the pointer still exists so the caller doesn't require a + * reference. + */ +struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port) +{ + struct edid *edid = NULL; + + /* we need to search for the port in the mgr in case it's gone */ + port = drm_dp_mst_topology_get_port_validated(mgr, port); + if (!port) + return NULL; + + if (port->cached_edid) + edid = drm_edid_duplicate(port->cached_edid); + else { + edid = drm_get_edid(connector, &port->aux.ddc); + } + port->has_audio = drm_detect_monitor_audio(edid); + drm_dp_mst_topology_put_port(port); + return edid; +} +EXPORT_SYMBOL(drm_dp_mst_get_edid); + +/** + * drm_dp_atomic_find_time_slots() - Find and add time slots to the state + * @state: global atomic state + * @mgr: MST topology manager for the port + * @port: port to find time slots for + * @pbn: bandwidth required for the mode in PBN + * + * Allocates time slots to @port, replacing any previous time slot allocations it may + * have had. Any atomic drivers which support MST must call this function in + * their &drm_encoder_helper_funcs.atomic_check() callback unconditionally to + * change the current time slot allocation for the new state, and ensure the MST + * atomic state is added whenever the state of payloads in the topology changes. + * + * Allocations set by this function are not checked against the bandwidth + * restraints of @mgr until the driver calls drm_dp_mst_atomic_check(). + * + * Additionally, it is OK to call this function multiple times on the same + * @port as needed. It is not OK however, to call this function and + * drm_dp_atomic_release_time_slots() in the same atomic check phase. + * + * See also: + * drm_dp_atomic_release_time_slots() + * drm_dp_mst_atomic_check() + * + * Returns: + * Total slots in the atomic state assigned for this port, or a negative error + * code if the port no longer exists + */ +int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state, + struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port, int pbn) +{ + struct drm_dp_mst_topology_state *topology_state; + struct drm_dp_mst_atomic_payload *payload = NULL; + struct drm_connector_state *conn_state; + int prev_slots = 0, prev_bw = 0, req_slots; + + topology_state = drm_atomic_get_mst_topology_state(state, mgr); + if (IS_ERR(topology_state)) + return PTR_ERR(topology_state); + + conn_state = drm_atomic_get_new_connector_state(state, port->connector); + topology_state->pending_crtc_mask |= drm_crtc_mask(conn_state->crtc); + + /* Find the current allocation for this port, if any */ + payload = drm_atomic_get_mst_payload_state(topology_state, port); + if (payload) { + prev_slots = payload->time_slots; + prev_bw = payload->pbn; + + /* + * This should never happen, unless the driver tries + * releasing and allocating the same timeslot allocation, + * which is an error + */ + if (drm_WARN_ON(mgr->dev, payload->delete)) { + drm_err(mgr->dev, + "cannot allocate and release time slots on [MST PORT:%p] in the same state\n", + port); + return -EINVAL; + } + } + + req_slots = DIV_ROUND_UP(pbn, topology_state->pbn_div); + + drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] TU %d -> %d\n", + port->connector->base.id, port->connector->name, + port, prev_slots, req_slots); + drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n", + port->connector->base.id, port->connector->name, + port, prev_bw, pbn); + + /* Add the new allocation to the state, note the VCPI isn't assigned until the end */ + if (!payload) { + payload = kzalloc(sizeof(*payload), GFP_KERNEL); + if (!payload) + return -ENOMEM; + + drm_dp_mst_get_port_malloc(port); + payload->port = port; + payload->vc_start_slot = -1; + list_add(&payload->next, &topology_state->payloads); + } + payload->time_slots = req_slots; + payload->pbn = pbn; + + return req_slots; +} +EXPORT_SYMBOL(drm_dp_atomic_find_time_slots); + +/** + * drm_dp_atomic_release_time_slots() - Release allocated time slots + * @state: global atomic state + * @mgr: MST topology manager for the port + * @port: The port to release the time slots from + * + * Releases any time slots that have been allocated to a port in the atomic + * state. Any atomic drivers which support MST must call this function + * unconditionally in their &drm_connector_helper_funcs.atomic_check() callback. + * This helper will check whether time slots would be released by the new state and + * respond accordingly, along with ensuring the MST state is always added to the + * atomic state whenever a new state would modify the state of payloads on the + * topology. + * + * It is OK to call this even if @port has been removed from the system. + * Additionally, it is OK to call this function multiple times on the same + * @port as needed. It is not OK however, to call this function and + * drm_dp_atomic_find_time_slots() on the same @port in a single atomic check + * phase. + * + * See also: + * drm_dp_atomic_find_time_slots() + * drm_dp_mst_atomic_check() + * + * Returns: + * 0 on success, negative error code otherwise + */ +int drm_dp_atomic_release_time_slots(struct drm_atomic_state *state, + struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port) +{ + struct drm_dp_mst_topology_state *topology_state; + struct drm_dp_mst_atomic_payload *payload; + struct drm_connector_state *old_conn_state, *new_conn_state; + bool update_payload = true; + + old_conn_state = drm_atomic_get_old_connector_state(state, port->connector); + if (!old_conn_state->crtc) + return 0; + + /* If the CRTC isn't disabled by this state, don't release it's payload */ + new_conn_state = drm_atomic_get_new_connector_state(state, port->connector); + if (new_conn_state->crtc) { + struct drm_crtc_state *crtc_state = + drm_atomic_get_new_crtc_state(state, new_conn_state->crtc); + + /* No modeset means no payload changes, so it's safe to not pull in the MST state */ + if (!crtc_state || !drm_atomic_crtc_needs_modeset(crtc_state)) + return 0; + + if (!crtc_state->mode_changed && !crtc_state->connectors_changed) + update_payload = false; + } + + topology_state = drm_atomic_get_mst_topology_state(state, mgr); + if (IS_ERR(topology_state)) + return PTR_ERR(topology_state); + + topology_state->pending_crtc_mask |= drm_crtc_mask(old_conn_state->crtc); + if (!update_payload) + return 0; + + payload = drm_atomic_get_mst_payload_state(topology_state, port); + if (WARN_ON(!payload)) { + drm_err(mgr->dev, "No payload for [MST PORT:%p] found in mst state %p\n", + port, &topology_state->base); + return -EINVAL; + } + + if (new_conn_state->crtc) + return 0; + + drm_dbg_atomic(mgr->dev, "[MST PORT:%p] TU %d -> 0\n", port, payload->time_slots); + if (!payload->delete) { + payload->pbn = 0; + payload->delete = true; + topology_state->payload_mask &= ~BIT(payload->vcpi - 1); + } + + return 0; +} +EXPORT_SYMBOL(drm_dp_atomic_release_time_slots); + +/** + * drm_dp_mst_atomic_setup_commit() - setup_commit hook for MST helpers + * @state: global atomic state + * + * This function saves all of the &drm_crtc_commit structs in an atomic state that touch any CRTCs + * currently assigned to an MST topology. Drivers must call this hook from their + * &drm_mode_config_helper_funcs.atomic_commit_setup hook. + * + * Returns: + * 0 if all CRTC commits were retrieved successfully, negative error code otherwise + */ +int drm_dp_mst_atomic_setup_commit(struct drm_atomic_state *state) +{ + struct drm_dp_mst_topology_mgr *mgr; + struct drm_dp_mst_topology_state *mst_state; + struct drm_crtc *crtc; + struct drm_crtc_state *crtc_state; + int i, j, commit_idx, num_commit_deps; + + for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) { + if (!mst_state->pending_crtc_mask) + continue; + + num_commit_deps = hweight32(mst_state->pending_crtc_mask); + mst_state->commit_deps = kmalloc_array(num_commit_deps, + sizeof(*mst_state->commit_deps), GFP_KERNEL); + if (!mst_state->commit_deps) + return -ENOMEM; + mst_state->num_commit_deps = num_commit_deps; + + commit_idx = 0; + for_each_new_crtc_in_state(state, crtc, crtc_state, j) { + if (mst_state->pending_crtc_mask & drm_crtc_mask(crtc)) { + mst_state->commit_deps[commit_idx++] = + drm_crtc_commit_get(crtc_state->commit); + } + } + } + + return 0; +} +EXPORT_SYMBOL(drm_dp_mst_atomic_setup_commit); + +/** + * drm_dp_mst_atomic_wait_for_dependencies() - Wait for all pending commits on MST topologies, + * prepare new MST state for commit + * @state: global atomic state + * + * Goes through any MST topologies in this atomic state, and waits for any pending commits which + * touched CRTCs that were/are on an MST topology to be programmed to hardware and flipped to before + * returning. This is to prevent multiple non-blocking commits affecting an MST topology from racing + * with eachother by forcing them to be executed sequentially in situations where the only resources + * the modeset objects in these commits share are an MST topology. + * + * This function also prepares the new MST state for commit by performing some state preparation + * which can't be done until this point, such as reading back the final VC start slots (which are + * determined at commit-time) from the previous state. + * + * All MST drivers must call this function after calling drm_atomic_helper_wait_for_dependencies(), + * or whatever their equivalent of that is. + */ +void drm_dp_mst_atomic_wait_for_dependencies(struct drm_atomic_state *state) +{ + struct drm_dp_mst_topology_state *old_mst_state, *new_mst_state; + struct drm_dp_mst_topology_mgr *mgr; + struct drm_dp_mst_atomic_payload *old_payload, *new_payload; + int i, j, ret; + + for_each_oldnew_mst_mgr_in_state(state, mgr, old_mst_state, new_mst_state, i) { + for (j = 0; j < old_mst_state->num_commit_deps; j++) { + ret = drm_crtc_commit_wait(old_mst_state->commit_deps[j]); + if (ret < 0) + drm_err(state->dev, "Failed to wait for %s: %d\n", + old_mst_state->commit_deps[j]->crtc->name, ret); + } + + /* Now that previous state is committed, it's safe to copy over the start slot + * assignments + */ + list_for_each_entry(old_payload, &old_mst_state->payloads, next) { + if (old_payload->delete) + continue; + + new_payload = drm_atomic_get_mst_payload_state(new_mst_state, + old_payload->port); + new_payload->vc_start_slot = old_payload->vc_start_slot; + } + } +} +EXPORT_SYMBOL(drm_dp_mst_atomic_wait_for_dependencies); + +/** + * drm_dp_mst_root_conn_atomic_check() - Serialize CRTC commits on MST-capable connectors operating + * in SST mode + * @new_conn_state: The new connector state of the &drm_connector + * @mgr: The MST topology manager for the &drm_connector + * + * Since MST uses fake &drm_encoder structs, the generic atomic modesetting code isn't able to + * serialize non-blocking commits happening on the real DP connector of an MST topology switching + * into/away from MST mode - as the CRTC on the real DP connector and the CRTCs on the connector's + * MST topology will never share the same &drm_encoder. + * + * This function takes care of this serialization issue, by checking a root MST connector's atomic + * state to determine if it is about to have a modeset - and then pulling in the MST topology state + * if so, along with adding any relevant CRTCs to &drm_dp_mst_topology_state.pending_crtc_mask. + * + * Drivers implementing MST must call this function from the + * &drm_connector_helper_funcs.atomic_check hook of any physical DP &drm_connector capable of + * driving MST sinks. + * + * Returns: + * 0 on success, negative error code otherwise + */ +int drm_dp_mst_root_conn_atomic_check(struct drm_connector_state *new_conn_state, + struct drm_dp_mst_topology_mgr *mgr) +{ + struct drm_atomic_state *state = new_conn_state->state; + struct drm_connector_state *old_conn_state = + drm_atomic_get_old_connector_state(state, new_conn_state->connector); + struct drm_crtc_state *crtc_state; + struct drm_dp_mst_topology_state *mst_state = NULL; + + if (new_conn_state->crtc) { + crtc_state = drm_atomic_get_new_crtc_state(state, new_conn_state->crtc); + if (crtc_state && drm_atomic_crtc_needs_modeset(crtc_state)) { + mst_state = drm_atomic_get_mst_topology_state(state, mgr); + if (IS_ERR(mst_state)) + return PTR_ERR(mst_state); + + mst_state->pending_crtc_mask |= drm_crtc_mask(new_conn_state->crtc); + } + } + + if (old_conn_state->crtc) { + crtc_state = drm_atomic_get_new_crtc_state(state, old_conn_state->crtc); + if (crtc_state && drm_atomic_crtc_needs_modeset(crtc_state)) { + if (!mst_state) { + mst_state = drm_atomic_get_mst_topology_state(state, mgr); + if (IS_ERR(mst_state)) + return PTR_ERR(mst_state); + } + + mst_state->pending_crtc_mask |= drm_crtc_mask(old_conn_state->crtc); + } + } + + return 0; +} +EXPORT_SYMBOL(drm_dp_mst_root_conn_atomic_check); + +/** + * drm_dp_mst_update_slots() - updates the slot info depending on the DP ecoding format + * @mst_state: mst_state to update + * @link_encoding_cap: the ecoding format on the link + */ +void drm_dp_mst_update_slots(struct drm_dp_mst_topology_state *mst_state, uint8_t link_encoding_cap) +{ + if (link_encoding_cap == DP_CAP_ANSI_128B132B) { + mst_state->total_avail_slots = 64; + mst_state->start_slot = 0; + } else { + mst_state->total_avail_slots = 63; + mst_state->start_slot = 1; + } + + DRM_DEBUG_KMS("%s encoding format on mst_state 0x%p\n", + (link_encoding_cap == DP_CAP_ANSI_128B132B) ? "128b/132b":"8b/10b", + mst_state); +} +EXPORT_SYMBOL(drm_dp_mst_update_slots); + +static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr, + int id, u8 start_slot, u8 num_slots) +{ + u8 payload_alloc[3], status; + int ret; + int retries = 0; + + drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, + DP_PAYLOAD_TABLE_UPDATED); + + payload_alloc[0] = id; + payload_alloc[1] = start_slot; + payload_alloc[2] = num_slots; + + ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3); + if (ret != 3) { + drm_dbg_kms(mgr->dev, "failed to write payload allocation %d\n", ret); + goto fail; + } + +retry: + ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status); + if (ret < 0) { + drm_dbg_kms(mgr->dev, "failed to read payload table status %d\n", ret); + goto fail; + } + + if (!(status & DP_PAYLOAD_TABLE_UPDATED)) { + retries++; + if (retries < 20) { + usleep_range(10000, 20000); + goto retry; + } + drm_dbg_kms(mgr->dev, "status not set after read payload table status %d\n", + status); + ret = -EINVAL; + goto fail; + } + ret = 0; +fail: + return ret; +} + +static int do_get_act_status(struct drm_dp_aux *aux) +{ + int ret; + u8 status; + + ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status); + if (ret < 0) + return ret; + + return status; +} + +/** + * drm_dp_check_act_status() - Polls for ACT handled status. + * @mgr: manager to use + * + * Tries waiting for the MST hub to finish updating it's payload table by + * polling for the ACT handled bit for up to 3 seconds (yes-some hubs really + * take that long). + * + * Returns: + * 0 if the ACT was handled in time, negative error code on failure. + */ +int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr) +{ + /* + * There doesn't seem to be any recommended retry count or timeout in + * the MST specification. Since some hubs have been observed to take + * over 1 second to update their payload allocations under certain + * conditions, we use a rather large timeout value. + */ + const int timeout_ms = 3000; + int ret, status; + + ret = readx_poll_timeout(do_get_act_status, mgr->aux, status, + status & DP_PAYLOAD_ACT_HANDLED || status < 0, + 200, timeout_ms * USEC_PER_MSEC); + if (ret < 0 && status >= 0) { + drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n", + timeout_ms, status); + return -EINVAL; + } else if (status < 0) { + /* + * Failure here isn't unexpected - the hub may have + * just been unplugged + */ + drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status); + return status; + } + + return 0; +} +EXPORT_SYMBOL(drm_dp_check_act_status); + +/** + * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode. + * @clock: dot clock for the mode + * @bpp: bpp for the mode. + * @dsc: DSC mode. If true, bpp has units of 1/16 of a bit per pixel + * + * This uses the formula in the spec to calculate the PBN value for a mode. + */ +int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc) +{ + /* + * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006 + * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on + * common multiplier to render an integer PBN for all link rate/lane + * counts combinations + * calculate + * peak_kbps *= (1006/1000) + * peak_kbps *= (64/54) + * peak_kbps *= 8 convert to bytes + * + * If the bpp is in units of 1/16, further divide by 16. Put this + * factor in the numerator rather than the denominator to avoid + * integer overflow + */ + + if (dsc) + return DIV_ROUND_UP_ULL(mul_u32_u32(clock * (bpp / 16), 64 * 1006), + 8 * 54 * 1000 * 1000); + + return DIV_ROUND_UP_ULL(mul_u32_u32(clock * bpp, 64 * 1006), + 8 * 54 * 1000 * 1000); +} +EXPORT_SYMBOL(drm_dp_calc_pbn_mode); + +/* we want to kick the TX after we've ack the up/down IRQs. */ +static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr) +{ + queue_work(system_long_wq, &mgr->tx_work); +} + +/* + * Helper function for parsing DP device types into convenient strings + * for use with dp_mst_topology + */ +static const char *pdt_to_string(u8 pdt) +{ + switch (pdt) { + case DP_PEER_DEVICE_NONE: + return "NONE"; + case DP_PEER_DEVICE_SOURCE_OR_SST: + return "SOURCE OR SST"; + case DP_PEER_DEVICE_MST_BRANCHING: + return "MST BRANCHING"; + case DP_PEER_DEVICE_SST_SINK: + return "SST SINK"; + case DP_PEER_DEVICE_DP_LEGACY_CONV: + return "DP LEGACY CONV"; + default: + return "ERR"; + } +} + +static void drm_dp_mst_dump_mstb(struct seq_file *m, + struct drm_dp_mst_branch *mstb) +{ + struct drm_dp_mst_port *port; + int tabs = mstb->lct; + char prefix[10]; + int i; + + for (i = 0; i < tabs; i++) + prefix[i] = '\t'; + prefix[i] = '\0'; + + seq_printf(m, "%smstb - [%p]: num_ports: %d\n", prefix, mstb, mstb->num_ports); + list_for_each_entry(port, &mstb->ports, next) { + seq_printf(m, "%sport %d - [%p] (%s - %s): ddps: %d, ldps: %d, sdp: %d/%d, fec: %s, conn: %p\n", + prefix, + port->port_num, + port, + port->input ? "input" : "output", + pdt_to_string(port->pdt), + port->ddps, + port->ldps, + port->num_sdp_streams, + port->num_sdp_stream_sinks, + port->fec_capable ? "true" : "false", + port->connector); + if (port->mstb) + drm_dp_mst_dump_mstb(m, port->mstb); + } +} + +#define DP_PAYLOAD_TABLE_SIZE 64 + +static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr, + char *buf) +{ + int i; + + for (i = 0; i < DP_PAYLOAD_TABLE_SIZE; i += 16) { + if (drm_dp_dpcd_read(mgr->aux, + DP_PAYLOAD_TABLE_UPDATE_STATUS + i, + &buf[i], 16) != 16) + return false; + } + return true; +} + +static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_port *port, char *name, + int namelen) +{ + struct edid *mst_edid; + + mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port); + drm_edid_get_monitor_name(mst_edid, name, namelen); + kfree(mst_edid); +} + +/** + * drm_dp_mst_dump_topology(): dump topology to seq file. + * @m: seq_file to dump output to + * @mgr: manager to dump current topology for. + * + * helper to dump MST topology to a seq file for debugfs. + */ +void drm_dp_mst_dump_topology(struct seq_file *m, + struct drm_dp_mst_topology_mgr *mgr) +{ + struct drm_dp_mst_topology_state *state; + struct drm_dp_mst_atomic_payload *payload; + int i, ret; + + mutex_lock(&mgr->lock); + if (mgr->mst_primary) + drm_dp_mst_dump_mstb(m, mgr->mst_primary); + + /* dump VCPIs */ + mutex_unlock(&mgr->lock); + + ret = drm_modeset_lock_single_interruptible(&mgr->base.lock); + if (ret < 0) + return; + + state = to_drm_dp_mst_topology_state(mgr->base.state); + seq_printf(m, "\n*** Atomic state info ***\n"); + seq_printf(m, "payload_mask: %x, max_payloads: %d, start_slot: %u, pbn_div: %d\n", + state->payload_mask, mgr->max_payloads, state->start_slot, state->pbn_div); + + seq_printf(m, "\n| idx | port | vcpi | slots | pbn | dsc | sink name |\n"); + for (i = 0; i < mgr->max_payloads; i++) { + list_for_each_entry(payload, &state->payloads, next) { + char name[14]; + + if (payload->vcpi != i || payload->delete) + continue; + + fetch_monitor_name(mgr, payload->port, name, sizeof(name)); + seq_printf(m, " %5d %6d %6d %02d - %02d %5d %5s %19s\n", + i, + payload->port->port_num, + payload->vcpi, + payload->vc_start_slot, + payload->vc_start_slot + payload->time_slots - 1, + payload->pbn, + payload->dsc_enabled ? "Y" : "N", + (*name != 0) ? name : "Unknown"); + } + } + + seq_printf(m, "\n*** DPCD Info ***\n"); + mutex_lock(&mgr->lock); + if (mgr->mst_primary) { + u8 buf[DP_PAYLOAD_TABLE_SIZE]; + int ret; + + if (drm_dp_read_dpcd_caps(mgr->aux, buf) < 0) { + seq_printf(m, "dpcd read failed\n"); + goto out; + } + seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf); + + ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2); + if (ret != 2) { + seq_printf(m, "faux/mst read failed\n"); + goto out; + } + seq_printf(m, "faux/mst: %*ph\n", 2, buf); + + ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1); + if (ret != 1) { + seq_printf(m, "mst ctrl read failed\n"); + goto out; + } + seq_printf(m, "mst ctrl: %*ph\n", 1, buf); + + /* dump the standard OUI branch header */ + ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE); + if (ret != DP_BRANCH_OUI_HEADER_SIZE) { + seq_printf(m, "branch oui read failed\n"); + goto out; + } + seq_printf(m, "branch oui: %*phN devid: ", 3, buf); + + for (i = 0x3; i < 0x8 && buf[i]; i++) + seq_printf(m, "%c", buf[i]); + seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n", + buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]); + if (dump_dp_payload_table(mgr, buf)) + seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf); + } + +out: + mutex_unlock(&mgr->lock); + drm_modeset_unlock(&mgr->base.lock); +} +EXPORT_SYMBOL(drm_dp_mst_dump_topology); + +static void drm_dp_tx_work(struct work_struct *work) +{ + struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work); + + mutex_lock(&mgr->qlock); + if (!list_empty(&mgr->tx_msg_downq)) + process_single_down_tx_qlock(mgr); + mutex_unlock(&mgr->qlock); +} + +static inline void +drm_dp_delayed_destroy_port(struct drm_dp_mst_port *port) +{ + drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs); + + if (port->connector) { + drm_connector_unregister(port->connector); + drm_connector_put(port->connector); + } + + drm_dp_mst_put_port_malloc(port); +} + +static inline void +drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch *mstb) +{ + struct drm_dp_mst_topology_mgr *mgr = mstb->mgr; + struct drm_dp_mst_port *port, *port_tmp; + struct drm_dp_sideband_msg_tx *txmsg, *txmsg_tmp; + bool wake_tx = false; + + mutex_lock(&mgr->lock); + list_for_each_entry_safe(port, port_tmp, &mstb->ports, next) { + list_del(&port->next); + drm_dp_mst_topology_put_port(port); + } + mutex_unlock(&mgr->lock); + + /* drop any tx slot msg */ + mutex_lock(&mstb->mgr->qlock); + list_for_each_entry_safe(txmsg, txmsg_tmp, &mgr->tx_msg_downq, next) { + if (txmsg->dst != mstb) + continue; + + txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT; + list_del(&txmsg->next); + wake_tx = true; + } + mutex_unlock(&mstb->mgr->qlock); + + if (wake_tx) + wake_up_all(&mstb->mgr->tx_waitq); + + drm_dp_mst_put_mstb_malloc(mstb); +} + +static void drm_dp_delayed_destroy_work(struct work_struct *work) +{ + struct drm_dp_mst_topology_mgr *mgr = + container_of(work, struct drm_dp_mst_topology_mgr, + delayed_destroy_work); + bool send_hotplug = false, go_again; + + /* + * Not a regular list traverse as we have to drop the destroy + * connector lock before destroying the mstb/port, to avoid AB->BA + * ordering between this lock and the config mutex. + */ + do { + go_again = false; + + for (;;) { + struct drm_dp_mst_branch *mstb; + + mutex_lock(&mgr->delayed_destroy_lock); + mstb = list_first_entry_or_null(&mgr->destroy_branch_device_list, + struct drm_dp_mst_branch, + destroy_next); + if (mstb) + list_del(&mstb->destroy_next); + mutex_unlock(&mgr->delayed_destroy_lock); + + if (!mstb) + break; + + drm_dp_delayed_destroy_mstb(mstb); + go_again = true; + } + + for (;;) { + struct drm_dp_mst_port *port; + + mutex_lock(&mgr->delayed_destroy_lock); + port = list_first_entry_or_null(&mgr->destroy_port_list, + struct drm_dp_mst_port, + next); + if (port) + list_del(&port->next); + mutex_unlock(&mgr->delayed_destroy_lock); + + if (!port) + break; + + drm_dp_delayed_destroy_port(port); + send_hotplug = true; + go_again = true; + } + } while (go_again); + + if (send_hotplug) + drm_kms_helper_hotplug_event(mgr->dev); +} + +static struct drm_private_state * +drm_dp_mst_duplicate_state(struct drm_private_obj *obj) +{ + struct drm_dp_mst_topology_state *state, *old_state = + to_dp_mst_topology_state(obj->state); + struct drm_dp_mst_atomic_payload *pos, *payload; + + state = kmemdup(old_state, sizeof(*state), GFP_KERNEL); + if (!state) + return NULL; + + __drm_atomic_helper_private_obj_duplicate_state(obj, &state->base); + + INIT_LIST_HEAD(&state->payloads); + state->commit_deps = NULL; + state->num_commit_deps = 0; + state->pending_crtc_mask = 0; + + list_for_each_entry(pos, &old_state->payloads, next) { + /* Prune leftover freed timeslot allocations */ + if (pos->delete) + continue; + + payload = kmemdup(pos, sizeof(*payload), GFP_KERNEL); + if (!payload) + goto fail; + + drm_dp_mst_get_port_malloc(payload->port); + list_add(&payload->next, &state->payloads); + } + + return &state->base; + +fail: + list_for_each_entry_safe(pos, payload, &state->payloads, next) { + drm_dp_mst_put_port_malloc(pos->port); + kfree(pos); + } + kfree(state); + + return NULL; +} + +static void drm_dp_mst_destroy_state(struct drm_private_obj *obj, + struct drm_private_state *state) +{ + struct drm_dp_mst_topology_state *mst_state = + to_dp_mst_topology_state(state); + struct drm_dp_mst_atomic_payload *pos, *tmp; + int i; + + list_for_each_entry_safe(pos, tmp, &mst_state->payloads, next) { + /* We only keep references to ports with active payloads */ + if (!pos->delete) + drm_dp_mst_put_port_malloc(pos->port); + kfree(pos); + } + + for (i = 0; i < mst_state->num_commit_deps; i++) + drm_crtc_commit_put(mst_state->commit_deps[i]); + + kfree(mst_state->commit_deps); + kfree(mst_state); +} + +static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port, + struct drm_dp_mst_branch *branch) +{ + while (port->parent) { + if (port->parent == branch) + return true; + + if (port->parent->port_parent) + port = port->parent->port_parent; + else + break; + } + return false; +} + +static int +drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port, + struct drm_dp_mst_topology_state *state); + +static int +drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb, + struct drm_dp_mst_topology_state *state) +{ + struct drm_dp_mst_atomic_payload *payload; + struct drm_dp_mst_port *port; + int pbn_used = 0, ret; + bool found = false; + + /* Check that we have at least one port in our state that's downstream + * of this branch, otherwise we can skip this branch + */ + list_for_each_entry(payload, &state->payloads, next) { + if (!payload->pbn || + !drm_dp_mst_port_downstream_of_branch(payload->port, mstb)) + continue; + + found = true; + break; + } + if (!found) + return 0; + + if (mstb->port_parent) + drm_dbg_atomic(mstb->mgr->dev, + "[MSTB:%p] [MST PORT:%p] Checking bandwidth limits on [MSTB:%p]\n", + mstb->port_parent->parent, mstb->port_parent, mstb); + else + drm_dbg_atomic(mstb->mgr->dev, "[MSTB:%p] Checking bandwidth limits\n", mstb); + + list_for_each_entry(port, &mstb->ports, next) { + ret = drm_dp_mst_atomic_check_port_bw_limit(port, state); + if (ret < 0) + return ret; + + pbn_used += ret; + } + + return pbn_used; +} + +static int +drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port, + struct drm_dp_mst_topology_state *state) +{ + struct drm_dp_mst_atomic_payload *payload; + int pbn_used = 0; + + if (port->pdt == DP_PEER_DEVICE_NONE) + return 0; + + if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) { + payload = drm_atomic_get_mst_payload_state(state, port); + if (!payload) + return 0; + + /* + * This could happen if the sink deasserted its HPD line, but + * the branch device still reports it as attached (PDT != NONE). + */ + if (!port->full_pbn) { + drm_dbg_atomic(port->mgr->dev, + "[MSTB:%p] [MST PORT:%p] no BW available for the port\n", + port->parent, port); + return -EINVAL; + } + + pbn_used = payload->pbn; + } else { + pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb, + state); + if (pbn_used <= 0) + return pbn_used; + } + + if (pbn_used > port->full_pbn) { + drm_dbg_atomic(port->mgr->dev, + "[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n", + port->parent, port, pbn_used, port->full_pbn); + return -ENOSPC; + } + + drm_dbg_atomic(port->mgr->dev, "[MSTB:%p] [MST PORT:%p] uses %d out of %d PBN\n", + port->parent, port, pbn_used, port->full_pbn); + + return pbn_used; +} + +static inline int +drm_dp_mst_atomic_check_payload_alloc_limits(struct drm_dp_mst_topology_mgr *mgr, + struct drm_dp_mst_topology_state *mst_state) +{ + struct drm_dp_mst_atomic_payload *payload; + int avail_slots = mst_state->total_avail_slots, payload_count = 0; + + list_for_each_entry(payload, &mst_state->payloads, next) { + /* Releasing payloads is always OK-even if the port is gone */ + if (payload->delete) { + drm_dbg_atomic(mgr->dev, "[MST PORT:%p] releases all time slots\n", + payload->port); + continue; + } + + drm_dbg_atomic(mgr->dev, "[MST PORT:%p] requires %d time slots\n", + payload->port, payload->time_slots); + + avail_slots -= payload->time_slots; + if (avail_slots < 0) { + drm_dbg_atomic(mgr->dev, + "[MST PORT:%p] not enough time slots in mst state %p (avail=%d)\n", + payload->port, mst_state, avail_slots + payload->time_slots); + return -ENOSPC; + } + + if (++payload_count > mgr->max_payloads) { + drm_dbg_atomic(mgr->dev, + "[MST MGR:%p] state %p has too many payloads (max=%d)\n", + mgr, mst_state, mgr->max_payloads); + return -EINVAL; + } + + /* Assign a VCPI */ + if (!payload->vcpi) { + payload->vcpi = ffz(mst_state->payload_mask) + 1; + drm_dbg_atomic(mgr->dev, "[MST PORT:%p] assigned VCPI #%d\n", + payload->port, payload->vcpi); + mst_state->payload_mask |= BIT(payload->vcpi - 1); + } + } + + if (!payload_count) + mst_state->pbn_div = 0; + + drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU pbn_div=%d avail=%d used=%d\n", + mgr, mst_state, mst_state->pbn_div, avail_slots, + mst_state->total_avail_slots - avail_slots); + + return 0; +} + +/** + * drm_dp_mst_add_affected_dsc_crtcs + * @state: Pointer to the new struct drm_dp_mst_topology_state + * @mgr: MST topology manager + * + * Whenever there is a change in mst topology + * DSC configuration would have to be recalculated + * therefore we need to trigger modeset on all affected + * CRTCs in that topology + * + * See also: + * drm_dp_mst_atomic_enable_dsc() + */ +int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm_dp_mst_topology_mgr *mgr) +{ + struct drm_dp_mst_topology_state *mst_state; + struct drm_dp_mst_atomic_payload *pos; + struct drm_connector *connector; + struct drm_connector_state *conn_state; + struct drm_crtc *crtc; + struct drm_crtc_state *crtc_state; + + mst_state = drm_atomic_get_mst_topology_state(state, mgr); + + if (IS_ERR(mst_state)) + return PTR_ERR(mst_state); + + list_for_each_entry(pos, &mst_state->payloads, next) { + + connector = pos->port->connector; + + if (!connector) + return -EINVAL; + + conn_state = drm_atomic_get_connector_state(state, connector); + + if (IS_ERR(conn_state)) + return PTR_ERR(conn_state); + + crtc = conn_state->crtc; + + if (!crtc) + continue; + + if (!drm_dp_mst_dsc_aux_for_port(pos->port)) + continue; + + crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc); + + if (IS_ERR(crtc_state)) + return PTR_ERR(crtc_state); + + drm_dbg_atomic(mgr->dev, "[MST MGR:%p] Setting mode_changed flag on CRTC %p\n", + mgr, crtc); + + crtc_state->mode_changed = true; + } + return 0; +} +EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs); + +/** + * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off + * @state: Pointer to the new drm_atomic_state + * @port: Pointer to the affected MST Port + * @pbn: Newly recalculated bw required for link with DSC enabled + * @enable: Boolean flag to enable or disable DSC on the port + * + * This function enables DSC on the given Port + * by recalculating its vcpi from pbn provided + * and sets dsc_enable flag to keep track of which + * ports have DSC enabled + * + */ +int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state, + struct drm_dp_mst_port *port, + int pbn, bool enable) +{ + struct drm_dp_mst_topology_state *mst_state; + struct drm_dp_mst_atomic_payload *payload; + int time_slots = 0; + + mst_state = drm_atomic_get_mst_topology_state(state, port->mgr); + if (IS_ERR(mst_state)) + return PTR_ERR(mst_state); + + payload = drm_atomic_get_mst_payload_state(mst_state, port); + if (!payload) { + drm_dbg_atomic(state->dev, + "[MST PORT:%p] Couldn't find payload in mst state %p\n", + port, mst_state); + return -EINVAL; + } + + if (payload->dsc_enabled == enable) { + drm_dbg_atomic(state->dev, + "[MST PORT:%p] DSC flag is already set to %d, returning %d time slots\n", + port, enable, payload->time_slots); + time_slots = payload->time_slots; + } + + if (enable) { + time_slots = drm_dp_atomic_find_time_slots(state, port->mgr, port, pbn); + drm_dbg_atomic(state->dev, + "[MST PORT:%p] Enabling DSC flag, reallocating %d time slots on the port\n", + port, time_slots); + if (time_slots < 0) + return -EINVAL; + } + + payload->dsc_enabled = enable; + + return time_slots; +} +EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc); + +/** + * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an + * atomic update is valid + * @state: Pointer to the new &struct drm_dp_mst_topology_state + * + * Checks the given topology state for an atomic update to ensure that it's + * valid. This includes checking whether there's enough bandwidth to support + * the new timeslot allocations in the atomic update. + * + * Any atomic drivers supporting DP MST must make sure to call this after + * checking the rest of their state in their + * &drm_mode_config_funcs.atomic_check() callback. + * + * See also: + * drm_dp_atomic_find_time_slots() + * drm_dp_atomic_release_time_slots() + * + * Returns: + * + * 0 if the new state is valid, negative error code otherwise. + */ +int drm_dp_mst_atomic_check(struct drm_atomic_state *state) +{ + struct drm_dp_mst_topology_mgr *mgr; + struct drm_dp_mst_topology_state *mst_state; + int i, ret = 0; + + for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) { + if (!mgr->mst_state) + continue; + + ret = drm_dp_mst_atomic_check_payload_alloc_limits(mgr, mst_state); + if (ret) + break; + + mutex_lock(&mgr->lock); + ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary, + mst_state); + mutex_unlock(&mgr->lock); + if (ret < 0) + break; + else + ret = 0; + } + + return ret; +} +EXPORT_SYMBOL(drm_dp_mst_atomic_check); + +const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = { + .atomic_duplicate_state = drm_dp_mst_duplicate_state, + .atomic_destroy_state = drm_dp_mst_destroy_state, +}; +EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs); + +/** + * drm_atomic_get_mst_topology_state: get MST topology state + * @state: global atomic state + * @mgr: MST topology manager, also the private object in this case + * + * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic + * state vtable so that the private object state returned is that of a MST + * topology object. + * + * RETURNS: + * + * The MST topology state or error pointer. + */ +struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state, + struct drm_dp_mst_topology_mgr *mgr) +{ + return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base)); +} +EXPORT_SYMBOL(drm_atomic_get_mst_topology_state); + +/** + * drm_atomic_get_old_mst_topology_state: get old MST topology state in atomic state, if any + * @state: global atomic state + * @mgr: MST topology manager, also the private object in this case + * + * This function wraps drm_atomic_get_old_private_obj_state() passing in the MST atomic + * state vtable so that the private object state returned is that of a MST + * topology object. + * + * Returns: + * + * The old MST topology state, or NULL if there's no topology state for this MST mgr + * in the global atomic state + */ +struct drm_dp_mst_topology_state * +drm_atomic_get_old_mst_topology_state(struct drm_atomic_state *state, + struct drm_dp_mst_topology_mgr *mgr) +{ + struct drm_private_state *old_priv_state = + drm_atomic_get_old_private_obj_state(state, &mgr->base); + + return old_priv_state ? to_dp_mst_topology_state(old_priv_state) : NULL; +} +EXPORT_SYMBOL(drm_atomic_get_old_mst_topology_state); + +/** + * drm_atomic_get_new_mst_topology_state: get new MST topology state in atomic state, if any + * @state: global atomic state + * @mgr: MST topology manager, also the private object in this case + * + * This function wraps drm_atomic_get_new_private_obj_state() passing in the MST atomic + * state vtable so that the private object state returned is that of a MST + * topology object. + * + * Returns: + * + * The new MST topology state, or NULL if there's no topology state for this MST mgr + * in the global atomic state + */ +struct drm_dp_mst_topology_state * +drm_atomic_get_new_mst_topology_state(struct drm_atomic_state *state, + struct drm_dp_mst_topology_mgr *mgr) +{ + struct drm_private_state *new_priv_state = + drm_atomic_get_new_private_obj_state(state, &mgr->base); + + return new_priv_state ? to_dp_mst_topology_state(new_priv_state) : NULL; +} +EXPORT_SYMBOL(drm_atomic_get_new_mst_topology_state); + +/** + * drm_dp_mst_topology_mgr_init - initialise a topology manager + * @mgr: manager struct to initialise + * @dev: device providing this structure - for i2c addition. + * @aux: DP helper aux channel to talk to this device + * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit + * @max_payloads: maximum number of payloads this GPU can source + * @conn_base_id: the connector object ID the MST device is connected to. + * + * Return 0 for success, or negative error code on failure + */ +int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr, + struct drm_device *dev, struct drm_dp_aux *aux, + int max_dpcd_transaction_bytes, int max_payloads, + int conn_base_id) +{ + struct drm_dp_mst_topology_state *mst_state; + + mutex_init(&mgr->lock); + mutex_init(&mgr->qlock); + mutex_init(&mgr->delayed_destroy_lock); + mutex_init(&mgr->up_req_lock); + mutex_init(&mgr->probe_lock); +#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS) + mutex_init(&mgr->topology_ref_history_lock); + stack_depot_init(); +#endif + INIT_LIST_HEAD(&mgr->tx_msg_downq); + INIT_LIST_HEAD(&mgr->destroy_port_list); + INIT_LIST_HEAD(&mgr->destroy_branch_device_list); + INIT_LIST_HEAD(&mgr->up_req_list); + + /* + * delayed_destroy_work will be queued on a dedicated WQ, so that any + * requeuing will be also flushed when deiniting the topology manager. + */ + mgr->delayed_destroy_wq = alloc_ordered_workqueue("drm_dp_mst_wq", 0); + if (mgr->delayed_destroy_wq == NULL) + return -ENOMEM; + + INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work); + INIT_WORK(&mgr->tx_work, drm_dp_tx_work); + INIT_WORK(&mgr->delayed_destroy_work, drm_dp_delayed_destroy_work); + INIT_WORK(&mgr->up_req_work, drm_dp_mst_up_req_work); + init_waitqueue_head(&mgr->tx_waitq); + mgr->dev = dev; + mgr->aux = aux; + mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes; + mgr->max_payloads = max_payloads; + mgr->conn_base_id = conn_base_id; + + mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL); + if (mst_state == NULL) + return -ENOMEM; + + mst_state->total_avail_slots = 63; + mst_state->start_slot = 1; + + mst_state->mgr = mgr; + INIT_LIST_HEAD(&mst_state->payloads); + + drm_atomic_private_obj_init(dev, &mgr->base, + &mst_state->base, + &drm_dp_mst_topology_state_funcs); + + return 0; +} +EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init); + +/** + * drm_dp_mst_topology_mgr_destroy() - destroy topology manager. + * @mgr: manager to destroy + */ +void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr) +{ + drm_dp_mst_topology_mgr_set_mst(mgr, false); + flush_work(&mgr->work); + /* The following will also drain any requeued work on the WQ. */ + if (mgr->delayed_destroy_wq) { + destroy_workqueue(mgr->delayed_destroy_wq); + mgr->delayed_destroy_wq = NULL; + } + mgr->dev = NULL; + mgr->aux = NULL; + drm_atomic_private_obj_fini(&mgr->base); + mgr->funcs = NULL; + + mutex_destroy(&mgr->delayed_destroy_lock); + mutex_destroy(&mgr->qlock); + mutex_destroy(&mgr->lock); + mutex_destroy(&mgr->up_req_lock); + mutex_destroy(&mgr->probe_lock); +#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS) + mutex_destroy(&mgr->topology_ref_history_lock); +#endif +} +EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy); + +static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num) +{ + int i; + + if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS) + return false; + + for (i = 0; i < num - 1; i++) { + if (msgs[i].flags & I2C_M_RD || + msgs[i].len > 0xff) + return false; + } + + return msgs[num - 1].flags & I2C_M_RD && + msgs[num - 1].len <= 0xff; +} + +static bool remote_i2c_write_ok(const struct i2c_msg msgs[], int num) +{ + int i; + + for (i = 0; i < num - 1; i++) { + if (msgs[i].flags & I2C_M_RD || !(msgs[i].flags & I2C_M_STOP) || + msgs[i].len > 0xff) + return false; + } + + return !(msgs[num - 1].flags & I2C_M_RD) && msgs[num - 1].len <= 0xff; +} + +static int drm_dp_mst_i2c_read(struct drm_dp_mst_branch *mstb, + struct drm_dp_mst_port *port, + struct i2c_msg *msgs, int num) +{ + struct drm_dp_mst_topology_mgr *mgr = port->mgr; + unsigned int i; + struct drm_dp_sideband_msg_req_body msg; + struct drm_dp_sideband_msg_tx *txmsg = NULL; + int ret; + + memset(&msg, 0, sizeof(msg)); + msg.req_type = DP_REMOTE_I2C_READ; + msg.u.i2c_read.num_transactions = num - 1; + msg.u.i2c_read.port_number = port->port_num; + for (i = 0; i < num - 1; i++) { + msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr; + msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len; + msg.u.i2c_read.transactions[i].bytes = msgs[i].buf; + msg.u.i2c_read.transactions[i].no_stop_bit = !(msgs[i].flags & I2C_M_STOP); + } + msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr; + msg.u.i2c_read.num_bytes_read = msgs[num - 1].len; + + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL); + if (!txmsg) { + ret = -ENOMEM; + goto out; + } + + txmsg->dst = mstb; + drm_dp_encode_sideband_req(&msg, txmsg); + + drm_dp_queue_down_tx(mgr, txmsg); + + ret = drm_dp_mst_wait_tx_reply(mstb, txmsg); + if (ret > 0) { + + if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) { + ret = -EREMOTEIO; + goto out; + } + if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) { + ret = -EIO; + goto out; + } + memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len); + ret = num; + } +out: + kfree(txmsg); + return ret; +} + +static int drm_dp_mst_i2c_write(struct drm_dp_mst_branch *mstb, + struct drm_dp_mst_port *port, + struct i2c_msg *msgs, int num) +{ + struct drm_dp_mst_topology_mgr *mgr = port->mgr; + unsigned int i; + struct drm_dp_sideband_msg_req_body msg; + struct drm_dp_sideband_msg_tx *txmsg = NULL; + int ret; + + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL); + if (!txmsg) { + ret = -ENOMEM; + goto out; + } + for (i = 0; i < num; i++) { + memset(&msg, 0, sizeof(msg)); + msg.req_type = DP_REMOTE_I2C_WRITE; + msg.u.i2c_write.port_number = port->port_num; + msg.u.i2c_write.write_i2c_device_id = msgs[i].addr; + msg.u.i2c_write.num_bytes = msgs[i].len; + msg.u.i2c_write.bytes = msgs[i].buf; + + memset(txmsg, 0, sizeof(*txmsg)); + txmsg->dst = mstb; + + drm_dp_encode_sideband_req(&msg, txmsg); + drm_dp_queue_down_tx(mgr, txmsg); + + ret = drm_dp_mst_wait_tx_reply(mstb, txmsg); + if (ret > 0) { + if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) { + ret = -EREMOTEIO; + goto out; + } + } else { + goto out; + } + } + ret = num; +out: + kfree(txmsg); + return ret; +} + +/* I2C device */ +static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, + struct i2c_msg *msgs, int num) +{ + struct drm_dp_aux *aux = adapter->algo_data; + struct drm_dp_mst_port *port = + container_of(aux, struct drm_dp_mst_port, aux); + struct drm_dp_mst_branch *mstb; + struct drm_dp_mst_topology_mgr *mgr = port->mgr; + int ret; + + mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent); + if (!mstb) + return -EREMOTEIO; + + if (remote_i2c_read_ok(msgs, num)) { + ret = drm_dp_mst_i2c_read(mstb, port, msgs, num); + } else if (remote_i2c_write_ok(msgs, num)) { + ret = drm_dp_mst_i2c_write(mstb, port, msgs, num); + } else { + drm_dbg_kms(mgr->dev, "Unsupported I2C transaction for MST device\n"); + ret = -EIO; + } + + drm_dp_mst_topology_put_mstb(mstb); + return ret; +} + +static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | + I2C_FUNC_SMBUS_READ_BLOCK_DATA | + I2C_FUNC_SMBUS_BLOCK_PROC_CALL | + I2C_FUNC_10BIT_ADDR; +} + +static const struct i2c_algorithm drm_dp_mst_i2c_algo = { + .functionality = drm_dp_mst_i2c_functionality, + .master_xfer = drm_dp_mst_i2c_xfer, +}; + +/** + * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX + * @port: The port to add the I2C bus on + * + * Returns 0 on success or a negative error code on failure. + */ +static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port) +{ + struct drm_dp_aux *aux = &port->aux; + struct device *parent_dev = port->mgr->dev->dev; + + aux->ddc.algo = &drm_dp_mst_i2c_algo; + aux->ddc.algo_data = aux; + aux->ddc.retries = 3; + + aux->ddc.class = I2C_CLASS_DDC; + aux->ddc.owner = THIS_MODULE; + /* FIXME: set the kdev of the port's connector as parent */ + aux->ddc.dev.parent = parent_dev; + aux->ddc.dev.of_node = parent_dev->of_node; + + strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev), + sizeof(aux->ddc.name)); + + return i2c_add_adapter(&aux->ddc); +} + +/** + * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter + * @port: The port to remove the I2C bus from + */ +static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port) +{ + i2c_del_adapter(&port->aux.ddc); +} + +/** + * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device + * @port: The port to check + * + * A single physical MST hub object can be represented in the topology + * by multiple branches, with virtual ports between those branches. + * + * As of DP1.4, An MST hub with internal (virtual) ports must expose + * certain DPCD registers over those ports. See sections 2.6.1.1.1 + * and 2.6.1.1.2 of Display Port specification v1.4 for details. + * + * May acquire mgr->lock + * + * Returns: + * true if the port is a virtual DP peer device, false otherwise + */ +static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port) +{ + struct drm_dp_mst_port *downstream_port; + + if (!port || port->dpcd_rev < DP_DPCD_REV_14) + return false; + + /* Virtual DP Sink (Internal Display Panel) */ + if (port->port_num >= 8) + return true; + + /* DP-to-HDMI Protocol Converter */ + if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV && + !port->mcs && + port->ldps) + return true; + + /* DP-to-DP */ + mutex_lock(&port->mgr->lock); + if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING && + port->mstb && + port->mstb->num_ports == 2) { + list_for_each_entry(downstream_port, &port->mstb->ports, next) { + if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK && + !downstream_port->input) { + mutex_unlock(&port->mgr->lock); + return true; + } + } + } + mutex_unlock(&port->mgr->lock); + + return false; +} + +/** + * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC + * @port: The port to check. A leaf of the MST tree with an attached display. + * + * Depending on the situation, DSC may be enabled via the endpoint aux, + * the immediately upstream aux, or the connector's physical aux. + * + * This is both the correct aux to read DSC_CAPABILITY and the + * correct aux to write DSC_ENABLED. + * + * This operation can be expensive (up to four aux reads), so + * the caller should cache the return. + * + * Returns: + * NULL if DSC cannot be enabled on this port, otherwise the aux device + */ +struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port) +{ + struct drm_dp_mst_port *immediate_upstream_port; + struct drm_dp_mst_port *fec_port; + struct drm_dp_desc desc = {}; + u8 endpoint_fec; + u8 endpoint_dsc; + + if (!port) + return NULL; + + if (port->parent->port_parent) + immediate_upstream_port = port->parent->port_parent; + else + immediate_upstream_port = NULL; + + fec_port = immediate_upstream_port; + while (fec_port) { + /* + * Each physical link (i.e. not a virtual port) between the + * output and the primary device must support FEC + */ + if (!drm_dp_mst_is_virtual_dpcd(fec_port) && + !fec_port->fec_capable) + return NULL; + + fec_port = fec_port->parent->port_parent; + } + + /* DP-to-DP peer device */ + if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) { + u8 upstream_dsc; + + if (drm_dp_dpcd_read(&port->aux, + DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1) + return NULL; + if (drm_dp_dpcd_read(&port->aux, + DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1) + return NULL; + if (drm_dp_dpcd_read(&immediate_upstream_port->aux, + DP_DSC_SUPPORT, &upstream_dsc, 1) != 1) + return NULL; + + /* Enpoint decompression with DP-to-DP peer device */ + if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) && + (endpoint_fec & DP_FEC_CAPABLE) && + (upstream_dsc & DP_DSC_PASSTHROUGH_IS_SUPPORTED)) { + port->passthrough_aux = &immediate_upstream_port->aux; + return &port->aux; + } + + /* Virtual DPCD decompression with DP-to-DP peer device */ + return &immediate_upstream_port->aux; + } + + /* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */ + if (drm_dp_mst_is_virtual_dpcd(port)) + return &port->aux; + + /* + * Synaptics quirk + * Applies to ports for which: + * - Physical aux has Synaptics OUI + * - DPv1.4 or higher + * - Port is on primary branch device + * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG) + */ + if (drm_dp_read_desc(port->mgr->aux, &desc, true)) + return NULL; + + if (drm_dp_has_quirk(&desc, DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) && + port->mgr->dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14 && + port->parent == port->mgr->mst_primary) { + u8 dpcd_ext[DP_RECEIVER_CAP_SIZE]; + + if (drm_dp_read_dpcd_caps(port->mgr->aux, dpcd_ext) < 0) + return NULL; + + if ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT) && + ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK) + != DP_DWN_STRM_PORT_TYPE_ANALOG)) + return port->mgr->aux; + } + + /* + * The check below verifies if the MST sink + * connected to the GPU is capable of DSC - + * therefore the endpoint needs to be + * both DSC and FEC capable. + */ + if (drm_dp_dpcd_read(&port->aux, + DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1) + return NULL; + if (drm_dp_dpcd_read(&port->aux, + DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1) + return NULL; + if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) && + (endpoint_fec & DP_FEC_CAPABLE)) + return &port->aux; + + return NULL; +} +EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port); |