diff options
Diffstat (limited to 'drivers/firmware/arm_scmi/driver.c')
| -rw-r--r-- | drivers/firmware/arm_scmi/driver.c | 2698 |
1 files changed, 2698 insertions, 0 deletions
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c new file mode 100644 index 000000000..fe06dc193 --- /dev/null +++ b/drivers/firmware/arm_scmi/driver.c @@ -0,0 +1,2698 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * System Control and Management Interface (SCMI) Message Protocol driver + * + * SCMI Message Protocol is used between the System Control Processor(SCP) + * and the Application Processors(AP). The Message Handling Unit(MHU) + * provides a mechanism for inter-processor communication between SCP's + * Cortex M3 and AP. + * + * SCP offers control and management of the core/cluster power states, + * various power domain DVFS including the core/cluster, certain system + * clocks configuration, thermal sensors and many others. + * + * Copyright (C) 2018-2021 ARM Ltd. + */ + +#include <linux/bitmap.h> +#include <linux/device.h> +#include <linux/export.h> +#include <linux/idr.h> +#include <linux/io.h> +#include <linux/io-64-nonatomic-hi-lo.h> +#include <linux/kernel.h> +#include <linux/ktime.h> +#include <linux/hashtable.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/of_address.h> +#include <linux/of_device.h> +#include <linux/processor.h> +#include <linux/refcount.h> +#include <linux/slab.h> + +#include "common.h" +#include "notify.h" + +#define CREATE_TRACE_POINTS +#include <trace/events/scmi.h> + +enum scmi_error_codes { + SCMI_SUCCESS = 0, /* Success */ + SCMI_ERR_SUPPORT = -1, /* Not supported */ + SCMI_ERR_PARAMS = -2, /* Invalid Parameters */ + SCMI_ERR_ACCESS = -3, /* Invalid access/permission denied */ + SCMI_ERR_ENTRY = -4, /* Not found */ + SCMI_ERR_RANGE = -5, /* Value out of range */ + SCMI_ERR_BUSY = -6, /* Device busy */ + SCMI_ERR_COMMS = -7, /* Communication Error */ + SCMI_ERR_GENERIC = -8, /* Generic Error */ + SCMI_ERR_HARDWARE = -9, /* Hardware Error */ + SCMI_ERR_PROTOCOL = -10,/* Protocol Error */ +}; + +/* List of all SCMI devices active in system */ +static LIST_HEAD(scmi_list); +/* Protection for the entire list */ +static DEFINE_MUTEX(scmi_list_mutex); +/* Track the unique id for the transfers for debug & profiling purpose */ +static atomic_t transfer_last_id; + +static DEFINE_IDR(scmi_requested_devices); +static DEFINE_MUTEX(scmi_requested_devices_mtx); + +/* Track globally the creation of SCMI SystemPower related devices */ +static bool scmi_syspower_registered; +/* Protect access to scmi_syspower_registered */ +static DEFINE_MUTEX(scmi_syspower_mtx); + +struct scmi_requested_dev { + const struct scmi_device_id *id_table; + struct list_head node; +}; + +/** + * struct scmi_xfers_info - Structure to manage transfer information + * + * @xfer_alloc_table: Bitmap table for allocated messages. + * Index of this bitmap table is also used for message + * sequence identifier. + * @xfer_lock: Protection for message allocation + * @max_msg: Maximum number of messages that can be pending + * @free_xfers: A free list for available to use xfers. It is initialized with + * a number of xfers equal to the maximum allowed in-flight + * messages. + * @pending_xfers: An hashtable, indexed by msg_hdr.seq, used to keep all the + * currently in-flight messages. + */ +struct scmi_xfers_info { + unsigned long *xfer_alloc_table; + spinlock_t xfer_lock; + int max_msg; + struct hlist_head free_xfers; + DECLARE_HASHTABLE(pending_xfers, SCMI_PENDING_XFERS_HT_ORDER_SZ); +}; + +/** + * struct scmi_protocol_instance - Describe an initialized protocol instance. + * @handle: Reference to the SCMI handle associated to this protocol instance. + * @proto: A reference to the protocol descriptor. + * @gid: A reference for per-protocol devres management. + * @users: A refcount to track effective users of this protocol. + * @priv: Reference for optional protocol private data. + * @ph: An embedded protocol handle that will be passed down to protocol + * initialization code to identify this instance. + * + * Each protocol is initialized independently once for each SCMI platform in + * which is defined by DT and implemented by the SCMI server fw. + */ +struct scmi_protocol_instance { + const struct scmi_handle *handle; + const struct scmi_protocol *proto; + void *gid; + refcount_t users; + void *priv; + struct scmi_protocol_handle ph; +}; + +#define ph_to_pi(h) container_of(h, struct scmi_protocol_instance, ph) + +/** + * struct scmi_info - Structure representing a SCMI instance + * + * @dev: Device pointer + * @desc: SoC description for this instance + * @version: SCMI revision information containing protocol version, + * implementation version and (sub-)vendor identification. + * @handle: Instance of SCMI handle to send to clients + * @tx_minfo: Universal Transmit Message management info + * @rx_minfo: Universal Receive Message management info + * @tx_idr: IDR object to map protocol id to Tx channel info pointer + * @rx_idr: IDR object to map protocol id to Rx channel info pointer + * @protocols: IDR for protocols' instance descriptors initialized for + * this SCMI instance: populated on protocol's first attempted + * usage. + * @protocols_mtx: A mutex to protect protocols instances initialization. + * @protocols_imp: List of protocols implemented, currently maximum of + * scmi_revision_info.num_protocols elements allocated by the + * base protocol + * @active_protocols: IDR storing device_nodes for protocols actually defined + * in the DT and confirmed as implemented by fw. + * @atomic_threshold: Optional system wide DT-configured threshold, expressed + * in microseconds, for atomic operations. + * Only SCMI synchronous commands reported by the platform + * to have an execution latency lesser-equal to the threshold + * should be considered for atomic mode operation: such + * decision is finally left up to the SCMI drivers. + * @notify_priv: Pointer to private data structure specific to notifications. + * @node: List head + * @users: Number of users of this instance + */ +struct scmi_info { + struct device *dev; + const struct scmi_desc *desc; + struct scmi_revision_info version; + struct scmi_handle handle; + struct scmi_xfers_info tx_minfo; + struct scmi_xfers_info rx_minfo; + struct idr tx_idr; + struct idr rx_idr; + struct idr protocols; + /* Ensure mutual exclusive access to protocols instance array */ + struct mutex protocols_mtx; + u8 *protocols_imp; + struct idr active_protocols; + unsigned int atomic_threshold; + void *notify_priv; + struct list_head node; + int users; +}; + +#define handle_to_scmi_info(h) container_of(h, struct scmi_info, handle) + +static const int scmi_linux_errmap[] = { + /* better than switch case as long as return value is continuous */ + 0, /* SCMI_SUCCESS */ + -EOPNOTSUPP, /* SCMI_ERR_SUPPORT */ + -EINVAL, /* SCMI_ERR_PARAM */ + -EACCES, /* SCMI_ERR_ACCESS */ + -ENOENT, /* SCMI_ERR_ENTRY */ + -ERANGE, /* SCMI_ERR_RANGE */ + -EBUSY, /* SCMI_ERR_BUSY */ + -ECOMM, /* SCMI_ERR_COMMS */ + -EIO, /* SCMI_ERR_GENERIC */ + -EREMOTEIO, /* SCMI_ERR_HARDWARE */ + -EPROTO, /* SCMI_ERR_PROTOCOL */ +}; + +static inline int scmi_to_linux_errno(int errno) +{ + int err_idx = -errno; + + if (err_idx >= SCMI_SUCCESS && err_idx < ARRAY_SIZE(scmi_linux_errmap)) + return scmi_linux_errmap[err_idx]; + return -EIO; +} + +void scmi_notification_instance_data_set(const struct scmi_handle *handle, + void *priv) +{ + struct scmi_info *info = handle_to_scmi_info(handle); + + info->notify_priv = priv; + /* Ensure updated protocol private date are visible */ + smp_wmb(); +} + +void *scmi_notification_instance_data_get(const struct scmi_handle *handle) +{ + struct scmi_info *info = handle_to_scmi_info(handle); + + /* Ensure protocols_private_data has been updated */ + smp_rmb(); + return info->notify_priv; +} + +/** + * scmi_xfer_token_set - Reserve and set new token for the xfer at hand + * + * @minfo: Pointer to Tx/Rx Message management info based on channel type + * @xfer: The xfer to act upon + * + * Pick the next unused monotonically increasing token and set it into + * xfer->hdr.seq: picking a monotonically increasing value avoids immediate + * reuse of freshly completed or timed-out xfers, thus mitigating the risk + * of incorrect association of a late and expired xfer with a live in-flight + * transaction, both happening to re-use the same token identifier. + * + * Since platform is NOT required to answer our request in-order we should + * account for a few rare but possible scenarios: + * + * - exactly 'next_token' may be NOT available so pick xfer_id >= next_token + * using find_next_zero_bit() starting from candidate next_token bit + * + * - all tokens ahead upto (MSG_TOKEN_ID_MASK - 1) are used in-flight but we + * are plenty of free tokens at start, so try a second pass using + * find_next_zero_bit() and starting from 0. + * + * X = used in-flight + * + * Normal + * ------ + * + * |- xfer_id picked + * -----------+---------------------------------------------------------- + * | | |X|X|X| | | | | | ... ... ... ... ... ... ... ... ... ... ...|X|X| + * ---------------------------------------------------------------------- + * ^ + * |- next_token + * + * Out-of-order pending at start + * ----------------------------- + * + * |- xfer_id picked, last_token fixed + * -----+---------------------------------------------------------------- + * |X|X| | | | |X|X| ... ... ... ... ... ... ... ... ... ... ... ...|X| | + * ---------------------------------------------------------------------- + * ^ + * |- next_token + * + * + * Out-of-order pending at end + * --------------------------- + * + * |- xfer_id picked, last_token fixed + * -----+---------------------------------------------------------------- + * |X|X| | | | |X|X| ... ... ... ... ... ... ... ... ... ... |X|X|X||X|X| + * ---------------------------------------------------------------------- + * ^ + * |- next_token + * + * Context: Assumes to be called with @xfer_lock already acquired. + * + * Return: 0 on Success or error + */ +static int scmi_xfer_token_set(struct scmi_xfers_info *minfo, + struct scmi_xfer *xfer) +{ + unsigned long xfer_id, next_token; + + /* + * Pick a candidate monotonic token in range [0, MSG_TOKEN_MAX - 1] + * using the pre-allocated transfer_id as a base. + * Note that the global transfer_id is shared across all message types + * so there could be holes in the allocated set of monotonic sequence + * numbers, but that is going to limit the effectiveness of the + * mitigation only in very rare limit conditions. + */ + next_token = (xfer->transfer_id & (MSG_TOKEN_MAX - 1)); + + /* Pick the next available xfer_id >= next_token */ + xfer_id = find_next_zero_bit(minfo->xfer_alloc_table, + MSG_TOKEN_MAX, next_token); + if (xfer_id == MSG_TOKEN_MAX) { + /* + * After heavily out-of-order responses, there are no free + * tokens ahead, but only at start of xfer_alloc_table so + * try again from the beginning. + */ + xfer_id = find_next_zero_bit(minfo->xfer_alloc_table, + MSG_TOKEN_MAX, 0); + /* + * Something is wrong if we got here since there can be a + * maximum number of (MSG_TOKEN_MAX - 1) in-flight messages + * but we have not found any free token [0, MSG_TOKEN_MAX - 1]. + */ + if (WARN_ON_ONCE(xfer_id == MSG_TOKEN_MAX)) + return -ENOMEM; + } + + /* Update +/- last_token accordingly if we skipped some hole */ + if (xfer_id != next_token) + atomic_add((int)(xfer_id - next_token), &transfer_last_id); + + /* Set in-flight */ + set_bit(xfer_id, minfo->xfer_alloc_table); + xfer->hdr.seq = (u16)xfer_id; + + return 0; +} + +/** + * scmi_xfer_token_clear - Release the token + * + * @minfo: Pointer to Tx/Rx Message management info based on channel type + * @xfer: The xfer to act upon + */ +static inline void scmi_xfer_token_clear(struct scmi_xfers_info *minfo, + struct scmi_xfer *xfer) +{ + clear_bit(xfer->hdr.seq, minfo->xfer_alloc_table); +} + +/** + * scmi_xfer_get() - Allocate one message + * + * @handle: Pointer to SCMI entity handle + * @minfo: Pointer to Tx/Rx Message management info based on channel type + * @set_pending: If true a monotonic token is picked and the xfer is added to + * the pending hash table. + * + * Helper function which is used by various message functions that are + * exposed to clients of this driver for allocating a message traffic event. + * + * Picks an xfer from the free list @free_xfers (if any available) and, if + * required, sets a monotonically increasing token and stores the inflight xfer + * into the @pending_xfers hashtable for later retrieval. + * + * The successfully initialized xfer is refcounted. + * + * Context: Holds @xfer_lock while manipulating @xfer_alloc_table and + * @free_xfers. + * + * Return: 0 if all went fine, else corresponding error. + */ +static struct scmi_xfer *scmi_xfer_get(const struct scmi_handle *handle, + struct scmi_xfers_info *minfo, + bool set_pending) +{ + int ret; + unsigned long flags; + struct scmi_xfer *xfer; + + spin_lock_irqsave(&minfo->xfer_lock, flags); + if (hlist_empty(&minfo->free_xfers)) { + spin_unlock_irqrestore(&minfo->xfer_lock, flags); + return ERR_PTR(-ENOMEM); + } + + /* grab an xfer from the free_list */ + xfer = hlist_entry(minfo->free_xfers.first, struct scmi_xfer, node); + hlist_del_init(&xfer->node); + + /* + * Allocate transfer_id early so that can be used also as base for + * monotonic sequence number generation if needed. + */ + xfer->transfer_id = atomic_inc_return(&transfer_last_id); + + if (set_pending) { + /* Pick and set monotonic token */ + ret = scmi_xfer_token_set(minfo, xfer); + if (!ret) { + hash_add(minfo->pending_xfers, &xfer->node, + xfer->hdr.seq); + xfer->pending = true; + } else { + dev_err(handle->dev, + "Failed to get monotonic token %d\n", ret); + hlist_add_head(&xfer->node, &minfo->free_xfers); + xfer = ERR_PTR(ret); + } + } + + if (!IS_ERR(xfer)) { + refcount_set(&xfer->users, 1); + atomic_set(&xfer->busy, SCMI_XFER_FREE); + } + spin_unlock_irqrestore(&minfo->xfer_lock, flags); + + return xfer; +} + +/** + * __scmi_xfer_put() - Release a message + * + * @minfo: Pointer to Tx/Rx Message management info based on channel type + * @xfer: message that was reserved by scmi_xfer_get + * + * After refcount check, possibly release an xfer, clearing the token slot, + * removing xfer from @pending_xfers and putting it back into free_xfers. + * + * This holds a spinlock to maintain integrity of internal data structures. + */ +static void +__scmi_xfer_put(struct scmi_xfers_info *minfo, struct scmi_xfer *xfer) +{ + unsigned long flags; + + spin_lock_irqsave(&minfo->xfer_lock, flags); + if (refcount_dec_and_test(&xfer->users)) { + if (xfer->pending) { + scmi_xfer_token_clear(minfo, xfer); + hash_del(&xfer->node); + xfer->pending = false; + } + hlist_add_head(&xfer->node, &minfo->free_xfers); + } + spin_unlock_irqrestore(&minfo->xfer_lock, flags); +} + +/** + * scmi_xfer_lookup_unlocked - Helper to lookup an xfer_id + * + * @minfo: Pointer to Tx/Rx Message management info based on channel type + * @xfer_id: Token ID to lookup in @pending_xfers + * + * Refcounting is untouched. + * + * Context: Assumes to be called with @xfer_lock already acquired. + * + * Return: A valid xfer on Success or error otherwise + */ +static struct scmi_xfer * +scmi_xfer_lookup_unlocked(struct scmi_xfers_info *minfo, u16 xfer_id) +{ + struct scmi_xfer *xfer = NULL; + + if (test_bit(xfer_id, minfo->xfer_alloc_table)) + xfer = XFER_FIND(minfo->pending_xfers, xfer_id); + + return xfer ?: ERR_PTR(-EINVAL); +} + +/** + * scmi_msg_response_validate - Validate message type against state of related + * xfer + * + * @cinfo: A reference to the channel descriptor. + * @msg_type: Message type to check + * @xfer: A reference to the xfer to validate against @msg_type + * + * This function checks if @msg_type is congruent with the current state of + * a pending @xfer; if an asynchronous delayed response is received before the + * related synchronous response (Out-of-Order Delayed Response) the missing + * synchronous response is assumed to be OK and completed, carrying on with the + * Delayed Response: this is done to address the case in which the underlying + * SCMI transport can deliver such out-of-order responses. + * + * Context: Assumes to be called with xfer->lock already acquired. + * + * Return: 0 on Success, error otherwise + */ +static inline int scmi_msg_response_validate(struct scmi_chan_info *cinfo, + u8 msg_type, + struct scmi_xfer *xfer) +{ + /* + * Even if a response was indeed expected on this slot at this point, + * a buggy platform could wrongly reply feeding us an unexpected + * delayed response we're not prepared to handle: bail-out safely + * blaming firmware. + */ + if (msg_type == MSG_TYPE_DELAYED_RESP && !xfer->async_done) { + dev_err(cinfo->dev, + "Delayed Response for %d not expected! Buggy F/W ?\n", + xfer->hdr.seq); + return -EINVAL; + } + + switch (xfer->state) { + case SCMI_XFER_SENT_OK: + if (msg_type == MSG_TYPE_DELAYED_RESP) { + /* + * Delayed Response expected but delivered earlier. + * Assume message RESPONSE was OK and skip state. + */ + xfer->hdr.status = SCMI_SUCCESS; + xfer->state = SCMI_XFER_RESP_OK; + complete(&xfer->done); + dev_warn(cinfo->dev, + "Received valid OoO Delayed Response for %d\n", + xfer->hdr.seq); + } + break; + case SCMI_XFER_RESP_OK: + if (msg_type != MSG_TYPE_DELAYED_RESP) + return -EINVAL; + break; + case SCMI_XFER_DRESP_OK: + /* No further message expected once in SCMI_XFER_DRESP_OK */ + return -EINVAL; + } + + return 0; +} + +/** + * scmi_xfer_state_update - Update xfer state + * + * @xfer: A reference to the xfer to update + * @msg_type: Type of message being processed. + * + * Note that this message is assumed to have been already successfully validated + * by @scmi_msg_response_validate(), so here we just update the state. + * + * Context: Assumes to be called on an xfer exclusively acquired using the + * busy flag. + */ +static inline void scmi_xfer_state_update(struct scmi_xfer *xfer, u8 msg_type) +{ + xfer->hdr.type = msg_type; + + /* Unknown command types were already discarded earlier */ + if (xfer->hdr.type == MSG_TYPE_COMMAND) + xfer->state = SCMI_XFER_RESP_OK; + else + xfer->state = SCMI_XFER_DRESP_OK; +} + +static bool scmi_xfer_acquired(struct scmi_xfer *xfer) +{ + int ret; + + ret = atomic_cmpxchg(&xfer->busy, SCMI_XFER_FREE, SCMI_XFER_BUSY); + + return ret == SCMI_XFER_FREE; +} + +/** + * scmi_xfer_command_acquire - Helper to lookup and acquire a command xfer + * + * @cinfo: A reference to the channel descriptor. + * @msg_hdr: A message header to use as lookup key + * + * When a valid xfer is found for the sequence number embedded in the provided + * msg_hdr, reference counting is properly updated and exclusive access to this + * xfer is granted till released with @scmi_xfer_command_release. + * + * Return: A valid @xfer on Success or error otherwise. + */ +static inline struct scmi_xfer * +scmi_xfer_command_acquire(struct scmi_chan_info *cinfo, u32 msg_hdr) +{ + int ret; + unsigned long flags; + struct scmi_xfer *xfer; + struct scmi_info *info = handle_to_scmi_info(cinfo->handle); + struct scmi_xfers_info *minfo = &info->tx_minfo; + u8 msg_type = MSG_XTRACT_TYPE(msg_hdr); + u16 xfer_id = MSG_XTRACT_TOKEN(msg_hdr); + + /* Are we even expecting this? */ + spin_lock_irqsave(&minfo->xfer_lock, flags); + xfer = scmi_xfer_lookup_unlocked(minfo, xfer_id); + if (IS_ERR(xfer)) { + dev_err(cinfo->dev, + "Message for %d type %d is not expected!\n", + xfer_id, msg_type); + spin_unlock_irqrestore(&minfo->xfer_lock, flags); + return xfer; + } + refcount_inc(&xfer->users); + spin_unlock_irqrestore(&minfo->xfer_lock, flags); + + spin_lock_irqsave(&xfer->lock, flags); + ret = scmi_msg_response_validate(cinfo, msg_type, xfer); + /* + * If a pending xfer was found which was also in a congruent state with + * the received message, acquire exclusive access to it setting the busy + * flag. + * Spins only on the rare limit condition of concurrent reception of + * RESP and DRESP for the same xfer. + */ + if (!ret) { + spin_until_cond(scmi_xfer_acquired(xfer)); + scmi_xfer_state_update(xfer, msg_type); + } + spin_unlock_irqrestore(&xfer->lock, flags); + + if (ret) { + dev_err(cinfo->dev, + "Invalid message type:%d for %d - HDR:0x%X state:%d\n", + msg_type, xfer_id, msg_hdr, xfer->state); + /* On error the refcount incremented above has to be dropped */ + __scmi_xfer_put(minfo, xfer); + xfer = ERR_PTR(-EINVAL); + } + + return xfer; +} + +static inline void scmi_xfer_command_release(struct scmi_info *info, + struct scmi_xfer *xfer) +{ + atomic_set(&xfer->busy, SCMI_XFER_FREE); + __scmi_xfer_put(&info->tx_minfo, xfer); +} + +static inline void scmi_clear_channel(struct scmi_info *info, + struct scmi_chan_info *cinfo) +{ + if (info->desc->ops->clear_channel) + info->desc->ops->clear_channel(cinfo); +} + +static inline bool is_polling_required(struct scmi_chan_info *cinfo, + struct scmi_info *info) +{ + return cinfo->no_completion_irq || info->desc->force_polling; +} + +static inline bool is_transport_polling_capable(struct scmi_info *info) +{ + return info->desc->ops->poll_done || + info->desc->sync_cmds_completed_on_ret; +} + +static inline bool is_polling_enabled(struct scmi_chan_info *cinfo, + struct scmi_info *info) +{ + return is_polling_required(cinfo, info) && + is_transport_polling_capable(info); +} + +static void scmi_handle_notification(struct scmi_chan_info *cinfo, + u32 msg_hdr, void *priv) +{ + struct scmi_xfer *xfer; + struct device *dev = cinfo->dev; + struct scmi_info *info = handle_to_scmi_info(cinfo->handle); + struct scmi_xfers_info *minfo = &info->rx_minfo; + ktime_t ts; + + ts = ktime_get_boottime(); + xfer = scmi_xfer_get(cinfo->handle, minfo, false); + if (IS_ERR(xfer)) { + dev_err(dev, "failed to get free message slot (%ld)\n", + PTR_ERR(xfer)); + scmi_clear_channel(info, cinfo); + return; + } + + unpack_scmi_header(msg_hdr, &xfer->hdr); + if (priv) + /* Ensure order between xfer->priv store and following ops */ + smp_store_mb(xfer->priv, priv); + info->desc->ops->fetch_notification(cinfo, info->desc->max_msg_size, + xfer); + + trace_scmi_msg_dump(xfer->hdr.protocol_id, xfer->hdr.id, "NOTI", + xfer->hdr.seq, xfer->hdr.status, + xfer->rx.buf, xfer->rx.len); + + scmi_notify(cinfo->handle, xfer->hdr.protocol_id, + xfer->hdr.id, xfer->rx.buf, xfer->rx.len, ts); + + trace_scmi_rx_done(xfer->transfer_id, xfer->hdr.id, + xfer->hdr.protocol_id, xfer->hdr.seq, + MSG_TYPE_NOTIFICATION); + + __scmi_xfer_put(minfo, xfer); + + scmi_clear_channel(info, cinfo); +} + +static void scmi_handle_response(struct scmi_chan_info *cinfo, + u32 msg_hdr, void *priv) +{ + struct scmi_xfer *xfer; + struct scmi_info *info = handle_to_scmi_info(cinfo->handle); + + xfer = scmi_xfer_command_acquire(cinfo, msg_hdr); + if (IS_ERR(xfer)) { + if (MSG_XTRACT_TYPE(msg_hdr) == MSG_TYPE_DELAYED_RESP) + scmi_clear_channel(info, cinfo); + return; + } + + /* rx.len could be shrunk in the sync do_xfer, so reset to maxsz */ + if (xfer->hdr.type == MSG_TYPE_DELAYED_RESP) + xfer->rx.len = info->desc->max_msg_size; + + if (priv) + /* Ensure order between xfer->priv store and following ops */ + smp_store_mb(xfer->priv, priv); + info->desc->ops->fetch_response(cinfo, xfer); + + trace_scmi_msg_dump(xfer->hdr.protocol_id, xfer->hdr.id, + xfer->hdr.type == MSG_TYPE_DELAYED_RESP ? + "DLYD" : "RESP", + xfer->hdr.seq, xfer->hdr.status, + xfer->rx.buf, xfer->rx.len); + + trace_scmi_rx_done(xfer->transfer_id, xfer->hdr.id, + xfer->hdr.protocol_id, xfer->hdr.seq, + xfer->hdr.type); + + if (xfer->hdr.type == MSG_TYPE_DELAYED_RESP) { + scmi_clear_channel(info, cinfo); + complete(xfer->async_done); + } else { + complete(&xfer->done); + } + + scmi_xfer_command_release(info, xfer); +} + +/** + * scmi_rx_callback() - callback for receiving messages + * + * @cinfo: SCMI channel info + * @msg_hdr: Message header + * @priv: Transport specific private data. + * + * Processes one received message to appropriate transfer information and + * signals completion of the transfer. + * + * NOTE: This function will be invoked in IRQ context, hence should be + * as optimal as possible. + */ +void scmi_rx_callback(struct scmi_chan_info *cinfo, u32 msg_hdr, void *priv) +{ + u8 msg_type = MSG_XTRACT_TYPE(msg_hdr); + + switch (msg_type) { + case MSG_TYPE_NOTIFICATION: + scmi_handle_notification(cinfo, msg_hdr, priv); + break; + case MSG_TYPE_COMMAND: + case MSG_TYPE_DELAYED_RESP: + scmi_handle_response(cinfo, msg_hdr, priv); + break; + default: + WARN_ONCE(1, "received unknown msg_type:%d\n", msg_type); + break; + } +} + +/** + * xfer_put() - Release a transmit message + * + * @ph: Pointer to SCMI protocol handle + * @xfer: message that was reserved by xfer_get_init + */ +static void xfer_put(const struct scmi_protocol_handle *ph, + struct scmi_xfer *xfer) +{ + const struct scmi_protocol_instance *pi = ph_to_pi(ph); + struct scmi_info *info = handle_to_scmi_info(pi->handle); + + __scmi_xfer_put(&info->tx_minfo, xfer); +} + +static bool scmi_xfer_done_no_timeout(struct scmi_chan_info *cinfo, + struct scmi_xfer *xfer, ktime_t stop) +{ + struct scmi_info *info = handle_to_scmi_info(cinfo->handle); + + /* + * Poll also on xfer->done so that polling can be forcibly terminated + * in case of out-of-order receptions of delayed responses + */ + return info->desc->ops->poll_done(cinfo, xfer) || + try_wait_for_completion(&xfer->done) || + ktime_after(ktime_get(), stop); +} + +/** + * scmi_wait_for_message_response - An helper to group all the possible ways of + * waiting for a synchronous message response. + * + * @cinfo: SCMI channel info + * @xfer: Reference to the transfer being waited for. + * + * Chooses waiting strategy (sleep-waiting vs busy-waiting) depending on + * configuration flags like xfer->hdr.poll_completion. + * + * Return: 0 on Success, error otherwise. + */ +static int scmi_wait_for_message_response(struct scmi_chan_info *cinfo, + struct scmi_xfer *xfer) +{ + struct scmi_info *info = handle_to_scmi_info(cinfo->handle); + struct device *dev = info->dev; + int ret = 0, timeout_ms = info->desc->max_rx_timeout_ms; + + trace_scmi_xfer_response_wait(xfer->transfer_id, xfer->hdr.id, + xfer->hdr.protocol_id, xfer->hdr.seq, + timeout_ms, + xfer->hdr.poll_completion); + + if (xfer->hdr.poll_completion) { + /* + * Real polling is needed only if transport has NOT declared + * itself to support synchronous commands replies. + */ + if (!info->desc->sync_cmds_completed_on_ret) { + /* + * Poll on xfer using transport provided .poll_done(); + * assumes no completion interrupt was available. + */ + ktime_t stop = ktime_add_ms(ktime_get(), timeout_ms); + + spin_until_cond(scmi_xfer_done_no_timeout(cinfo, + xfer, stop)); + if (ktime_after(ktime_get(), stop)) { + dev_err(dev, + "timed out in resp(caller: %pS) - polling\n", + (void *)_RET_IP_); + ret = -ETIMEDOUT; + } + } + + if (!ret) { + unsigned long flags; + + /* + * Do not fetch_response if an out-of-order delayed + * response is being processed. + */ + spin_lock_irqsave(&xfer->lock, flags); + if (xfer->state == SCMI_XFER_SENT_OK) { + info->desc->ops->fetch_response(cinfo, xfer); + xfer->state = SCMI_XFER_RESP_OK; + } + spin_unlock_irqrestore(&xfer->lock, flags); + + /* Trace polled replies. */ + trace_scmi_msg_dump(xfer->hdr.protocol_id, xfer->hdr.id, + "RESP", + xfer->hdr.seq, xfer->hdr.status, + xfer->rx.buf, xfer->rx.len); + } + } else { + /* And we wait for the response. */ + if (!wait_for_completion_timeout(&xfer->done, + msecs_to_jiffies(timeout_ms))) { + dev_err(dev, "timed out in resp(caller: %pS)\n", + (void *)_RET_IP_); + ret = -ETIMEDOUT; + } + } + + return ret; +} + +/** + * do_xfer() - Do one transfer + * + * @ph: Pointer to SCMI protocol handle + * @xfer: Transfer to initiate and wait for response + * + * Return: -ETIMEDOUT in case of no response, if transmit error, + * return corresponding error, else if all goes well, + * return 0. + */ +static int do_xfer(const struct scmi_protocol_handle *ph, + struct scmi_xfer *xfer) +{ + int ret; + const struct scmi_protocol_instance *pi = ph_to_pi(ph); + struct scmi_info *info = handle_to_scmi_info(pi->handle); + struct device *dev = info->dev; + struct scmi_chan_info *cinfo; + + /* Check for polling request on custom command xfers at first */ + if (xfer->hdr.poll_completion && !is_transport_polling_capable(info)) { + dev_warn_once(dev, + "Polling mode is not supported by transport.\n"); + return -EINVAL; + } + + cinfo = idr_find(&info->tx_idr, pi->proto->id); + if (unlikely(!cinfo)) + return -EINVAL; + + /* True ONLY if also supported by transport. */ + if (is_polling_enabled(cinfo, info)) + xfer->hdr.poll_completion = true; + + /* + * Initialise protocol id now from protocol handle to avoid it being + * overridden by mistake (or malice) by the protocol code mangling with + * the scmi_xfer structure prior to this. + */ + xfer->hdr.protocol_id = pi->proto->id; + reinit_completion(&xfer->done); + + trace_scmi_xfer_begin(xfer->transfer_id, xfer->hdr.id, + xfer->hdr.protocol_id, xfer->hdr.seq, + xfer->hdr.poll_completion); + + /* Clear any stale status */ + xfer->hdr.status = SCMI_SUCCESS; + xfer->state = SCMI_XFER_SENT_OK; + /* + * Even though spinlocking is not needed here since no race is possible + * on xfer->state due to the monotonically increasing tokens allocation, + * we must anyway ensure xfer->state initialization is not re-ordered + * after the .send_message() to be sure that on the RX path an early + * ISR calling scmi_rx_callback() cannot see an old stale xfer->state. + */ + smp_mb(); + + ret = info->desc->ops->send_message(cinfo, xfer); + if (ret < 0) { + dev_dbg(dev, "Failed to send message %d\n", ret); + return ret; + } + + trace_scmi_msg_dump(xfer->hdr.protocol_id, xfer->hdr.id, "CMND", + xfer->hdr.seq, xfer->hdr.status, + xfer->tx.buf, xfer->tx.len); + + ret = scmi_wait_for_message_response(cinfo, xfer); + if (!ret && xfer->hdr.status) + ret = scmi_to_linux_errno(xfer->hdr.status); + + if (info->desc->ops->mark_txdone) + info->desc->ops->mark_txdone(cinfo, ret, xfer); + + trace_scmi_xfer_end(xfer->transfer_id, xfer->hdr.id, + xfer->hdr.protocol_id, xfer->hdr.seq, ret); + + return ret; +} + +static void reset_rx_to_maxsz(const struct scmi_protocol_handle *ph, + struct scmi_xfer *xfer) +{ + const struct scmi_protocol_instance *pi = ph_to_pi(ph); + struct scmi_info *info = handle_to_scmi_info(pi->handle); + + xfer->rx.len = info->desc->max_msg_size; +} + +#define SCMI_MAX_RESPONSE_TIMEOUT (2 * MSEC_PER_SEC) + +/** + * do_xfer_with_response() - Do one transfer and wait until the delayed + * response is received + * + * @ph: Pointer to SCMI protocol handle + * @xfer: Transfer to initiate and wait for response + * + * Using asynchronous commands in atomic/polling mode should be avoided since + * it could cause long busy-waiting here, so ignore polling for the delayed + * response and WARN if it was requested for this command transaction since + * upper layers should refrain from issuing such kind of requests. + * + * The only other option would have been to refrain from using any asynchronous + * command even if made available, when an atomic transport is detected, and + * instead forcibly use the synchronous version (thing that can be easily + * attained at the protocol layer), but this would also have led to longer + * stalls of the channel for synchronous commands and possibly timeouts. + * (in other words there is usually a good reason if a platform provides an + * asynchronous version of a command and we should prefer to use it...just not + * when using atomic/polling mode) + * + * Return: -ETIMEDOUT in case of no delayed response, if transmit error, + * return corresponding error, else if all goes well, return 0. + */ +static int do_xfer_with_response(const struct scmi_protocol_handle *ph, + struct scmi_xfer *xfer) +{ + int ret, timeout = msecs_to_jiffies(SCMI_MAX_RESPONSE_TIMEOUT); + DECLARE_COMPLETION_ONSTACK(async_response); + + xfer->async_done = &async_response; + + /* + * Delayed responses should not be polled, so an async command should + * not have been used when requiring an atomic/poll context; WARN and + * perform instead a sleeping wait. + * (Note Async + IgnoreDelayedResponses are sent via do_xfer) + */ + WARN_ON_ONCE(xfer->hdr.poll_completion); + + ret = do_xfer(ph, xfer); + if (!ret) { + if (!wait_for_completion_timeout(xfer->async_done, timeout)) { + dev_err(ph->dev, + "timed out in delayed resp(caller: %pS)\n", + (void *)_RET_IP_); + ret = -ETIMEDOUT; + } else if (xfer->hdr.status) { + ret = scmi_to_linux_errno(xfer->hdr.status); + } + } + + xfer->async_done = NULL; + return ret; +} + +/** + * xfer_get_init() - Allocate and initialise one message for transmit + * + * @ph: Pointer to SCMI protocol handle + * @msg_id: Message identifier + * @tx_size: transmit message size + * @rx_size: receive message size + * @p: pointer to the allocated and initialised message + * + * This function allocates the message using @scmi_xfer_get and + * initialise the header. + * + * Return: 0 if all went fine with @p pointing to message, else + * corresponding error. + */ +static int xfer_get_init(const struct scmi_protocol_handle *ph, + u8 msg_id, size_t tx_size, size_t rx_size, + struct scmi_xfer **p) +{ + int ret; + struct scmi_xfer *xfer; + const struct scmi_protocol_instance *pi = ph_to_pi(ph); + struct scmi_info *info = handle_to_scmi_info(pi->handle); + struct scmi_xfers_info *minfo = &info->tx_minfo; + struct device *dev = info->dev; + + /* Ensure we have sane transfer sizes */ + if (rx_size > info->desc->max_msg_size || + tx_size > info->desc->max_msg_size) + return -ERANGE; + + xfer = scmi_xfer_get(pi->handle, minfo, true); + if (IS_ERR(xfer)) { + ret = PTR_ERR(xfer); + dev_err(dev, "failed to get free message slot(%d)\n", ret); + return ret; + } + + xfer->tx.len = tx_size; + xfer->rx.len = rx_size ? : info->desc->max_msg_size; + xfer->hdr.type = MSG_TYPE_COMMAND; + xfer->hdr.id = msg_id; + xfer->hdr.poll_completion = false; + + *p = xfer; + + return 0; +} + +/** + * version_get() - command to get the revision of the SCMI entity + * + * @ph: Pointer to SCMI protocol handle + * @version: Holds returned version of protocol. + * + * Updates the SCMI information in the internal data structure. + * + * Return: 0 if all went fine, else return appropriate error. + */ +static int version_get(const struct scmi_protocol_handle *ph, u32 *version) +{ + int ret; + __le32 *rev_info; + struct scmi_xfer *t; + + ret = xfer_get_init(ph, PROTOCOL_VERSION, 0, sizeof(*version), &t); + if (ret) + return ret; + + ret = do_xfer(ph, t); + if (!ret) { + rev_info = t->rx.buf; + *version = le32_to_cpu(*rev_info); + } + + xfer_put(ph, t); + return ret; +} + +/** + * scmi_set_protocol_priv - Set protocol specific data at init time + * + * @ph: A reference to the protocol handle. + * @priv: The private data to set. + * + * Return: 0 on Success + */ +static int scmi_set_protocol_priv(const struct scmi_protocol_handle *ph, + void *priv) +{ + struct scmi_protocol_instance *pi = ph_to_pi(ph); + + pi->priv = priv; + + return 0; +} + +/** + * scmi_get_protocol_priv - Set protocol specific data at init time + * + * @ph: A reference to the protocol handle. + * + * Return: Protocol private data if any was set. + */ +static void *scmi_get_protocol_priv(const struct scmi_protocol_handle *ph) +{ + const struct scmi_protocol_instance *pi = ph_to_pi(ph); + + return pi->priv; +} + +static const struct scmi_xfer_ops xfer_ops = { + .version_get = version_get, + .xfer_get_init = xfer_get_init, + .reset_rx_to_maxsz = reset_rx_to_maxsz, + .do_xfer = do_xfer, + .do_xfer_with_response = do_xfer_with_response, + .xfer_put = xfer_put, +}; + +struct scmi_msg_resp_domain_name_get { + __le32 flags; + u8 name[SCMI_MAX_STR_SIZE]; +}; + +/** + * scmi_common_extended_name_get - Common helper to get extended resources name + * @ph: A protocol handle reference. + * @cmd_id: The specific command ID to use. + * @res_id: The specific resource ID to use. + * @name: A pointer to the preallocated area where the retrieved name will be + * stored as a NULL terminated string. + * @len: The len in bytes of the @name char array. + * + * Return: 0 on Succcess + */ +static int scmi_common_extended_name_get(const struct scmi_protocol_handle *ph, + u8 cmd_id, u32 res_id, char *name, + size_t len) +{ + int ret; + struct scmi_xfer *t; + struct scmi_msg_resp_domain_name_get *resp; + + ret = ph->xops->xfer_get_init(ph, cmd_id, sizeof(res_id), + sizeof(*resp), &t); + if (ret) + goto out; + + put_unaligned_le32(res_id, t->tx.buf); + resp = t->rx.buf; + + ret = ph->xops->do_xfer(ph, t); + if (!ret) + strscpy(name, resp->name, len); + + ph->xops->xfer_put(ph, t); +out: + if (ret) + dev_warn(ph->dev, + "Failed to get extended name - id:%u (ret:%d). Using %s\n", + res_id, ret, name); + return ret; +} + +/** + * struct scmi_iterator - Iterator descriptor + * @msg: A reference to the message TX buffer; filled by @prepare_message with + * a proper custom command payload for each multi-part command request. + * @resp: A reference to the response RX buffer; used by @update_state and + * @process_response to parse the multi-part replies. + * @t: A reference to the underlying xfer initialized and used transparently by + * the iterator internal routines. + * @ph: A reference to the associated protocol handle to be used. + * @ops: A reference to the custom provided iterator operations. + * @state: The current iterator state; used and updated in turn by the iterators + * internal routines and by the caller-provided @scmi_iterator_ops. + * @priv: A reference to optional private data as provided by the caller and + * passed back to the @@scmi_iterator_ops. + */ +struct scmi_iterator { + void *msg; + void *resp; + struct scmi_xfer *t; + const struct scmi_protocol_handle *ph; + struct scmi_iterator_ops *ops; + struct scmi_iterator_state state; + void *priv; +}; + +static void *scmi_iterator_init(const struct scmi_protocol_handle *ph, + struct scmi_iterator_ops *ops, + unsigned int max_resources, u8 msg_id, + size_t tx_size, void *priv) +{ + int ret; + struct scmi_iterator *i; + + i = devm_kzalloc(ph->dev, sizeof(*i), GFP_KERNEL); + if (!i) + return ERR_PTR(-ENOMEM); + + i->ph = ph; + i->ops = ops; + i->priv = priv; + + ret = ph->xops->xfer_get_init(ph, msg_id, tx_size, 0, &i->t); + if (ret) { + devm_kfree(ph->dev, i); + return ERR_PTR(ret); + } + + i->state.max_resources = max_resources; + i->msg = i->t->tx.buf; + i->resp = i->t->rx.buf; + + return i; +} + +static int scmi_iterator_run(void *iter) +{ + int ret = -EINVAL; + struct scmi_iterator_ops *iops; + const struct scmi_protocol_handle *ph; + struct scmi_iterator_state *st; + struct scmi_iterator *i = iter; + + if (!i || !i->ops || !i->ph) + return ret; + + iops = i->ops; + ph = i->ph; + st = &i->state; + + do { + iops->prepare_message(i->msg, st->desc_index, i->priv); + ret = ph->xops->do_xfer(ph, i->t); + if (ret) + break; + + st->rx_len = i->t->rx.len; + ret = iops->update_state(st, i->resp, i->priv); + if (ret) + break; + + if (st->num_returned > st->max_resources - st->desc_index) { + dev_err(ph->dev, + "No. of resources can't exceed %d\n", + st->max_resources); + ret = -EINVAL; + break; + } + + for (st->loop_idx = 0; st->loop_idx < st->num_returned; + st->loop_idx++) { + ret = iops->process_response(ph, i->resp, st, i->priv); + if (ret) + goto out; + } + + st->desc_index += st->num_returned; + ph->xops->reset_rx_to_maxsz(ph, i->t); + /* + * check for both returned and remaining to avoid infinite + * loop due to buggy firmware + */ + } while (st->num_returned && st->num_remaining); + +out: + /* Finalize and destroy iterator */ + ph->xops->xfer_put(ph, i->t); + devm_kfree(ph->dev, i); + + return ret; +} + +struct scmi_msg_get_fc_info { + __le32 domain; + __le32 message_id; +}; + +struct scmi_msg_resp_desc_fc { + __le32 attr; +#define SUPPORTS_DOORBELL(x) ((x) & BIT(0)) +#define DOORBELL_REG_WIDTH(x) FIELD_GET(GENMASK(2, 1), (x)) + __le32 rate_limit; + __le32 chan_addr_low; + __le32 chan_addr_high; + __le32 chan_size; + __le32 db_addr_low; + __le32 db_addr_high; + __le32 db_set_lmask; + __le32 db_set_hmask; + __le32 db_preserve_lmask; + __le32 db_preserve_hmask; +}; + +static void +scmi_common_fastchannel_init(const struct scmi_protocol_handle *ph, + u8 describe_id, u32 message_id, u32 valid_size, + u32 domain, void __iomem **p_addr, + struct scmi_fc_db_info **p_db) +{ + int ret; + u32 flags; + u64 phys_addr; + u8 size; + void __iomem *addr; + struct scmi_xfer *t; + struct scmi_fc_db_info *db = NULL; + struct scmi_msg_get_fc_info *info; + struct scmi_msg_resp_desc_fc *resp; + const struct scmi_protocol_instance *pi = ph_to_pi(ph); + + if (!p_addr) { + ret = -EINVAL; + goto err_out; + } + + ret = ph->xops->xfer_get_init(ph, describe_id, + sizeof(*info), sizeof(*resp), &t); + if (ret) + goto err_out; + + info = t->tx.buf; + info->domain = cpu_to_le32(domain); + info->message_id = cpu_to_le32(message_id); + + /* + * Bail out on error leaving fc_info addresses zeroed; this includes + * the case in which the requested domain/message_id does NOT support + * fastchannels at all. + */ + ret = ph->xops->do_xfer(ph, t); + if (ret) + goto err_xfer; + + resp = t->rx.buf; + flags = le32_to_cpu(resp->attr); + size = le32_to_cpu(resp->chan_size); + if (size != valid_size) { + ret = -EINVAL; + goto err_xfer; + } + + phys_addr = le32_to_cpu(resp->chan_addr_low); + phys_addr |= (u64)le32_to_cpu(resp->chan_addr_high) << 32; + addr = devm_ioremap(ph->dev, phys_addr, size); + if (!addr) { + ret = -EADDRNOTAVAIL; + goto err_xfer; + } + + *p_addr = addr; + + if (p_db && SUPPORTS_DOORBELL(flags)) { + db = devm_kzalloc(ph->dev, sizeof(*db), GFP_KERNEL); + if (!db) { + ret = -ENOMEM; + goto err_db; + } + + size = 1 << DOORBELL_REG_WIDTH(flags); + phys_addr = le32_to_cpu(resp->db_addr_low); + phys_addr |= (u64)le32_to_cpu(resp->db_addr_high) << 32; + addr = devm_ioremap(ph->dev, phys_addr, size); + if (!addr) { + ret = -EADDRNOTAVAIL; + goto err_db_mem; + } + + db->addr = addr; + db->width = size; + db->set = le32_to_cpu(resp->db_set_lmask); + db->set |= (u64)le32_to_cpu(resp->db_set_hmask) << 32; + db->mask = le32_to_cpu(resp->db_preserve_lmask); + db->mask |= (u64)le32_to_cpu(resp->db_preserve_hmask) << 32; + + *p_db = db; + } + + ph->xops->xfer_put(ph, t); + + dev_dbg(ph->dev, + "Using valid FC for protocol %X [MSG_ID:%u / RES_ID:%u]\n", + pi->proto->id, message_id, domain); + + return; + +err_db_mem: + devm_kfree(ph->dev, db); + +err_db: + *p_addr = NULL; + +err_xfer: + ph->xops->xfer_put(ph, t); + +err_out: + dev_warn(ph->dev, + "Failed to get FC for protocol %X [MSG_ID:%u / RES_ID:%u] - ret:%d. Using regular messaging.\n", + pi->proto->id, message_id, domain, ret); +} + +#define SCMI_PROTO_FC_RING_DB(w) \ +do { \ + u##w val = 0; \ + \ + if (db->mask) \ + val = ioread##w(db->addr) & db->mask; \ + iowrite##w((u##w)db->set | val, db->addr); \ +} while (0) + +static void scmi_common_fastchannel_db_ring(struct scmi_fc_db_info *db) +{ + if (!db || !db->addr) + return; + + if (db->width == 1) + SCMI_PROTO_FC_RING_DB(8); + else if (db->width == 2) + SCMI_PROTO_FC_RING_DB(16); + else if (db->width == 4) + SCMI_PROTO_FC_RING_DB(32); + else /* db->width == 8 */ +#ifdef CONFIG_64BIT + SCMI_PROTO_FC_RING_DB(64); +#else + { + u64 val = 0; + + if (db->mask) + val = ioread64_hi_lo(db->addr) & db->mask; + iowrite64_hi_lo(db->set | val, db->addr); + } +#endif +} + +static const struct scmi_proto_helpers_ops helpers_ops = { + .extended_name_get = scmi_common_extended_name_get, + .iter_response_init = scmi_iterator_init, + .iter_response_run = scmi_iterator_run, + .fastchannel_init = scmi_common_fastchannel_init, + .fastchannel_db_ring = scmi_common_fastchannel_db_ring, +}; + +/** + * scmi_revision_area_get - Retrieve version memory area. + * + * @ph: A reference to the protocol handle. + * + * A helper to grab the version memory area reference during SCMI Base protocol + * initialization. + * + * Return: A reference to the version memory area associated to the SCMI + * instance underlying this protocol handle. + */ +struct scmi_revision_info * +scmi_revision_area_get(const struct scmi_protocol_handle *ph) +{ + const struct scmi_protocol_instance *pi = ph_to_pi(ph); + + return pi->handle->version; +} + +/** + * scmi_alloc_init_protocol_instance - Allocate and initialize a protocol + * instance descriptor. + * @info: The reference to the related SCMI instance. + * @proto: The protocol descriptor. + * + * Allocate a new protocol instance descriptor, using the provided @proto + * description, against the specified SCMI instance @info, and initialize it; + * all resources management is handled via a dedicated per-protocol devres + * group. + * + * Context: Assumes to be called with @protocols_mtx already acquired. + * Return: A reference to a freshly allocated and initialized protocol instance + * or ERR_PTR on failure. On failure the @proto reference is at first + * put using @scmi_protocol_put() before releasing all the devres group. + */ +static struct scmi_protocol_instance * +scmi_alloc_init_protocol_instance(struct scmi_info *info, + const struct scmi_protocol *proto) +{ + int ret = -ENOMEM; + void *gid; + struct scmi_protocol_instance *pi; + const struct scmi_handle *handle = &info->handle; + + /* Protocol specific devres group */ + gid = devres_open_group(handle->dev, NULL, GFP_KERNEL); + if (!gid) { + scmi_protocol_put(proto->id); + goto out; + } + + pi = devm_kzalloc(handle->dev, sizeof(*pi), GFP_KERNEL); + if (!pi) + goto clean; + + pi->gid = gid; + pi->proto = proto; + pi->handle = handle; + pi->ph.dev = handle->dev; + pi->ph.xops = &xfer_ops; + pi->ph.hops = &helpers_ops; + pi->ph.set_priv = scmi_set_protocol_priv; + pi->ph.get_priv = scmi_get_protocol_priv; + refcount_set(&pi->users, 1); + /* proto->init is assured NON NULL by scmi_protocol_register */ + ret = pi->proto->instance_init(&pi->ph); + if (ret) + goto clean; + + ret = idr_alloc(&info->protocols, pi, proto->id, proto->id + 1, + GFP_KERNEL); + if (ret != proto->id) + goto clean; + + /* + * Warn but ignore events registration errors since we do not want + * to skip whole protocols if their notifications are messed up. + */ + if (pi->proto->events) { + ret = scmi_register_protocol_events(handle, pi->proto->id, + &pi->ph, + pi->proto->events); + if (ret) + dev_warn(handle->dev, + "Protocol:%X - Events Registration Failed - err:%d\n", + pi->proto->id, ret); + } + + devres_close_group(handle->dev, pi->gid); + dev_dbg(handle->dev, "Initialized protocol: 0x%X\n", pi->proto->id); + + return pi; + +clean: + /* Take care to put the protocol module's owner before releasing all */ + scmi_protocol_put(proto->id); + devres_release_group(handle->dev, gid); +out: + return ERR_PTR(ret); +} + +/** + * scmi_get_protocol_instance - Protocol initialization helper. + * @handle: A reference to the SCMI platform instance. + * @protocol_id: The protocol being requested. + * + * In case the required protocol has never been requested before for this + * instance, allocate and initialize all the needed structures while handling + * resource allocation with a dedicated per-protocol devres subgroup. + * + * Return: A reference to an initialized protocol instance or error on failure: + * in particular returns -EPROBE_DEFER when the desired protocol could + * NOT be found. + */ +static struct scmi_protocol_instance * __must_check +scmi_get_protocol_instance(const struct scmi_handle *handle, u8 protocol_id) +{ + struct scmi_protocol_instance *pi; + struct scmi_info *info = handle_to_scmi_info(handle); + + mutex_lock(&info->protocols_mtx); + pi = idr_find(&info->protocols, protocol_id); + + if (pi) { + refcount_inc(&pi->users); + } else { + const struct scmi_protocol *proto; + + /* Fails if protocol not registered on bus */ + proto = scmi_protocol_get(protocol_id); + if (proto) + pi = scmi_alloc_init_protocol_instance(info, proto); + else + pi = ERR_PTR(-EPROBE_DEFER); + } + mutex_unlock(&info->protocols_mtx); + + return pi; +} + +/** + * scmi_protocol_acquire - Protocol acquire + * @handle: A reference to the SCMI platform instance. + * @protocol_id: The protocol being requested. + * + * Register a new user for the requested protocol on the specified SCMI + * platform instance, possibly triggering its initialization on first user. + * + * Return: 0 if protocol was acquired successfully. + */ +int scmi_protocol_acquire(const struct scmi_handle *handle, u8 protocol_id) +{ + return PTR_ERR_OR_ZERO(scmi_get_protocol_instance(handle, protocol_id)); +} + +/** + * scmi_protocol_release - Protocol de-initialization helper. + * @handle: A reference to the SCMI platform instance. + * @protocol_id: The protocol being requested. + * + * Remove one user for the specified protocol and triggers de-initialization + * and resources de-allocation once the last user has gone. + */ +void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id) +{ + struct scmi_info *info = handle_to_scmi_info(handle); + struct scmi_protocol_instance *pi; + + mutex_lock(&info->protocols_mtx); + pi = idr_find(&info->protocols, protocol_id); + if (WARN_ON(!pi)) + goto out; + + if (refcount_dec_and_test(&pi->users)) { + void *gid = pi->gid; + + if (pi->proto->events) + scmi_deregister_protocol_events(handle, protocol_id); + + if (pi->proto->instance_deinit) + pi->proto->instance_deinit(&pi->ph); + + idr_remove(&info->protocols, protocol_id); + + scmi_protocol_put(protocol_id); + + devres_release_group(handle->dev, gid); + dev_dbg(handle->dev, "De-Initialized protocol: 0x%X\n", + protocol_id); + } + +out: + mutex_unlock(&info->protocols_mtx); +} + +void scmi_setup_protocol_implemented(const struct scmi_protocol_handle *ph, + u8 *prot_imp) +{ + const struct scmi_protocol_instance *pi = ph_to_pi(ph); + struct scmi_info *info = handle_to_scmi_info(pi->handle); + + info->protocols_imp = prot_imp; +} + +static bool +scmi_is_protocol_implemented(const struct scmi_handle *handle, u8 prot_id) +{ + int i; + struct scmi_info *info = handle_to_scmi_info(handle); + struct scmi_revision_info *rev = handle->version; + + if (!info->protocols_imp) + return false; + + for (i = 0; i < rev->num_protocols; i++) + if (info->protocols_imp[i] == prot_id) + return true; + return false; +} + +struct scmi_protocol_devres { + const struct scmi_handle *handle; + u8 protocol_id; +}; + +static void scmi_devm_release_protocol(struct device *dev, void *res) +{ + struct scmi_protocol_devres *dres = res; + + scmi_protocol_release(dres->handle, dres->protocol_id); +} + +static struct scmi_protocol_instance __must_check * +scmi_devres_protocol_instance_get(struct scmi_device *sdev, u8 protocol_id) +{ + struct scmi_protocol_instance *pi; + struct scmi_protocol_devres *dres; + + dres = devres_alloc(scmi_devm_release_protocol, + sizeof(*dres), GFP_KERNEL); + if (!dres) + return ERR_PTR(-ENOMEM); + + pi = scmi_get_protocol_instance(sdev->handle, protocol_id); + if (IS_ERR(pi)) { + devres_free(dres); + return pi; + } + + dres->handle = sdev->handle; + dres->protocol_id = protocol_id; + devres_add(&sdev->dev, dres); + + return pi; +} + +/** + * scmi_devm_protocol_get - Devres managed get protocol operations and handle + * @sdev: A reference to an scmi_device whose embedded struct device is to + * be used for devres accounting. + * @protocol_id: The protocol being requested. + * @ph: A pointer reference used to pass back the associated protocol handle. + * + * Get hold of a protocol accounting for its usage, eventually triggering its + * initialization, and returning the protocol specific operations and related + * protocol handle which will be used as first argument in most of the + * protocols operations methods. + * Being a devres based managed method, protocol hold will be automatically + * released, and possibly de-initialized on last user, once the SCMI driver + * owning the scmi_device is unbound from it. + * + * Return: A reference to the requested protocol operations or error. + * Must be checked for errors by caller. + */ +static const void __must_check * +scmi_devm_protocol_get(struct scmi_device *sdev, u8 protocol_id, + struct scmi_protocol_handle **ph) +{ + struct scmi_protocol_instance *pi; + + if (!ph) + return ERR_PTR(-EINVAL); + + pi = scmi_devres_protocol_instance_get(sdev, protocol_id); + if (IS_ERR(pi)) + return pi; + + *ph = &pi->ph; + + return pi->proto->ops; +} + +/** + * scmi_devm_protocol_acquire - Devres managed helper to get hold of a protocol + * @sdev: A reference to an scmi_device whose embedded struct device is to + * be used for devres accounting. + * @protocol_id: The protocol being requested. + * + * Get hold of a protocol accounting for its usage, possibly triggering its + * initialization but without getting access to its protocol specific operations + * and handle. + * + * Being a devres based managed method, protocol hold will be automatically + * released, and possibly de-initialized on last user, once the SCMI driver + * owning the scmi_device is unbound from it. + * + * Return: 0 on SUCCESS + */ +static int __must_check scmi_devm_protocol_acquire(struct scmi_device *sdev, + u8 protocol_id) +{ + struct scmi_protocol_instance *pi; + + pi = scmi_devres_protocol_instance_get(sdev, protocol_id); + if (IS_ERR(pi)) + return PTR_ERR(pi); + + return 0; +} + +static int scmi_devm_protocol_match(struct device *dev, void *res, void *data) +{ + struct scmi_protocol_devres *dres = res; + + if (WARN_ON(!dres || !data)) + return 0; + + return dres->protocol_id == *((u8 *)data); +} + +/** + * scmi_devm_protocol_put - Devres managed put protocol operations and handle + * @sdev: A reference to an scmi_device whose embedded struct device is to + * be used for devres accounting. + * @protocol_id: The protocol being requested. + * + * Explicitly release a protocol hold previously obtained calling the above + * @scmi_devm_protocol_get. + */ +static void scmi_devm_protocol_put(struct scmi_device *sdev, u8 protocol_id) +{ + int ret; + + ret = devres_release(&sdev->dev, scmi_devm_release_protocol, + scmi_devm_protocol_match, &protocol_id); + WARN_ON(ret); +} + +/** + * scmi_is_transport_atomic - Method to check if underlying transport for an + * SCMI instance is configured as atomic. + * + * @handle: A reference to the SCMI platform instance. + * @atomic_threshold: An optional return value for the system wide currently + * configured threshold for atomic operations. + * + * Return: True if transport is configured as atomic + */ +static bool scmi_is_transport_atomic(const struct scmi_handle *handle, + unsigned int *atomic_threshold) +{ + bool ret; + struct scmi_info *info = handle_to_scmi_info(handle); + + ret = info->desc->atomic_enabled && is_transport_polling_capable(info); + if (ret && atomic_threshold) + *atomic_threshold = info->atomic_threshold; + + return ret; +} + +static inline +struct scmi_handle *scmi_handle_get_from_info_unlocked(struct scmi_info *info) +{ + info->users++; + return &info->handle; +} + +/** + * scmi_handle_get() - Get the SCMI handle for a device + * + * @dev: pointer to device for which we want SCMI handle + * + * NOTE: The function does not track individual clients of the framework + * and is expected to be maintained by caller of SCMI protocol library. + * scmi_handle_put must be balanced with successful scmi_handle_get + * + * Return: pointer to handle if successful, NULL on error + */ +struct scmi_handle *scmi_handle_get(struct device *dev) +{ + struct list_head *p; + struct scmi_info *info; + struct scmi_handle *handle = NULL; + + mutex_lock(&scmi_list_mutex); + list_for_each(p, &scmi_list) { + info = list_entry(p, struct scmi_info, node); + if (dev->parent == info->dev) { + handle = scmi_handle_get_from_info_unlocked(info); + break; + } + } + mutex_unlock(&scmi_list_mutex); + + return handle; +} + +/** + * scmi_handle_put() - Release the handle acquired by scmi_handle_get + * + * @handle: handle acquired by scmi_handle_get + * + * NOTE: The function does not track individual clients of the framework + * and is expected to be maintained by caller of SCMI protocol library. + * scmi_handle_put must be balanced with successful scmi_handle_get + * + * Return: 0 is successfully released + * if null was passed, it returns -EINVAL; + */ +int scmi_handle_put(const struct scmi_handle *handle) +{ + struct scmi_info *info; + + if (!handle) + return -EINVAL; + + info = handle_to_scmi_info(handle); + mutex_lock(&scmi_list_mutex); + if (!WARN_ON(!info->users)) + info->users--; + mutex_unlock(&scmi_list_mutex); + + return 0; +} + +static int __scmi_xfer_info_init(struct scmi_info *sinfo, + struct scmi_xfers_info *info) +{ + int i; + struct scmi_xfer *xfer; + struct device *dev = sinfo->dev; + const struct scmi_desc *desc = sinfo->desc; + + /* Pre-allocated messages, no more than what hdr.seq can support */ + if (WARN_ON(!info->max_msg || info->max_msg > MSG_TOKEN_MAX)) { + dev_err(dev, + "Invalid maximum messages %d, not in range [1 - %lu]\n", + info->max_msg, MSG_TOKEN_MAX); + return -EINVAL; + } + + hash_init(info->pending_xfers); + + /* Allocate a bitmask sized to hold MSG_TOKEN_MAX tokens */ + info->xfer_alloc_table = devm_kcalloc(dev, BITS_TO_LONGS(MSG_TOKEN_MAX), + sizeof(long), GFP_KERNEL); + if (!info->xfer_alloc_table) + return -ENOMEM; + + /* + * Preallocate a number of xfers equal to max inflight messages, + * pre-initialize the buffer pointer to pre-allocated buffers and + * attach all of them to the free list + */ + INIT_HLIST_HEAD(&info->free_xfers); + for (i = 0; i < info->max_msg; i++) { + xfer = devm_kzalloc(dev, sizeof(*xfer), GFP_KERNEL); + if (!xfer) + return -ENOMEM; + + xfer->rx.buf = devm_kcalloc(dev, sizeof(u8), desc->max_msg_size, + GFP_KERNEL); + if (!xfer->rx.buf) + return -ENOMEM; + + xfer->tx.buf = xfer->rx.buf; + init_completion(&xfer->done); + spin_lock_init(&xfer->lock); + + /* Add initialized xfer to the free list */ + hlist_add_head(&xfer->node, &info->free_xfers); + } + + spin_lock_init(&info->xfer_lock); + + return 0; +} + +static int scmi_channels_max_msg_configure(struct scmi_info *sinfo) +{ + const struct scmi_desc *desc = sinfo->desc; + + if (!desc->ops->get_max_msg) { + sinfo->tx_minfo.max_msg = desc->max_msg; + sinfo->rx_minfo.max_msg = desc->max_msg; + } else { + struct scmi_chan_info *base_cinfo; + + base_cinfo = idr_find(&sinfo->tx_idr, SCMI_PROTOCOL_BASE); + if (!base_cinfo) + return -EINVAL; + sinfo->tx_minfo.max_msg = desc->ops->get_max_msg(base_cinfo); + + /* RX channel is optional so can be skipped */ + base_cinfo = idr_find(&sinfo->rx_idr, SCMI_PROTOCOL_BASE); + if (base_cinfo) + sinfo->rx_minfo.max_msg = + desc->ops->get_max_msg(base_cinfo); + } + + return 0; +} + +static int scmi_xfer_info_init(struct scmi_info *sinfo) +{ + int ret; + + ret = scmi_channels_max_msg_configure(sinfo); + if (ret) + return ret; + + ret = __scmi_xfer_info_init(sinfo, &sinfo->tx_minfo); + if (!ret && !idr_is_empty(&sinfo->rx_idr)) + ret = __scmi_xfer_info_init(sinfo, &sinfo->rx_minfo); + + return ret; +} + +static int scmi_chan_setup(struct scmi_info *info, struct device *dev, + int prot_id, bool tx) +{ + int ret, idx; + struct scmi_chan_info *cinfo; + struct idr *idr; + + /* Transmit channel is first entry i.e. index 0 */ + idx = tx ? 0 : 1; + idr = tx ? &info->tx_idr : &info->rx_idr; + + /* check if already allocated, used for multiple device per protocol */ + cinfo = idr_find(idr, prot_id); + if (cinfo) + return 0; + + if (!info->desc->ops->chan_available(dev, idx)) { + cinfo = idr_find(idr, SCMI_PROTOCOL_BASE); + if (unlikely(!cinfo)) /* Possible only if platform has no Rx */ + return -EINVAL; + goto idr_alloc; + } + + cinfo = devm_kzalloc(info->dev, sizeof(*cinfo), GFP_KERNEL); + if (!cinfo) + return -ENOMEM; + + cinfo->dev = dev; + cinfo->rx_timeout_ms = info->desc->max_rx_timeout_ms; + + ret = info->desc->ops->chan_setup(cinfo, info->dev, tx); + if (ret) + return ret; + + if (tx && is_polling_required(cinfo, info)) { + if (is_transport_polling_capable(info)) + dev_info(dev, + "Enabled polling mode TX channel - prot_id:%d\n", + prot_id); + else + dev_warn(dev, + "Polling mode NOT supported by transport.\n"); + } + +idr_alloc: + ret = idr_alloc(idr, cinfo, prot_id, prot_id + 1, GFP_KERNEL); + if (ret != prot_id) { + dev_err(dev, "unable to allocate SCMI idr slot err %d\n", ret); + return ret; + } + + cinfo->handle = &info->handle; + return 0; +} + +static inline int +scmi_txrx_setup(struct scmi_info *info, struct device *dev, int prot_id) +{ + int ret = scmi_chan_setup(info, dev, prot_id, true); + + if (!ret) { + /* Rx is optional, report only memory errors */ + ret = scmi_chan_setup(info, dev, prot_id, false); + if (ret && ret != -ENOMEM) + ret = 0; + } + + return ret; +} + +/** + * scmi_get_protocol_device - Helper to get/create an SCMI device. + * + * @np: A device node representing a valid active protocols for the referred + * SCMI instance. + * @info: The referred SCMI instance for which we are getting/creating this + * device. + * @prot_id: The protocol ID. + * @name: The device name. + * + * Referring to the specific SCMI instance identified by @info, this helper + * takes care to return a properly initialized device matching the requested + * @proto_id and @name: if device was still not existent it is created as a + * child of the specified SCMI instance @info and its transport properly + * initialized as usual. + * + * Return: A properly initialized scmi device, NULL otherwise. + */ +static inline struct scmi_device * +scmi_get_protocol_device(struct device_node *np, struct scmi_info *info, + int prot_id, const char *name) +{ + struct scmi_device *sdev; + + /* Already created for this parent SCMI instance ? */ + sdev = scmi_child_dev_find(info->dev, prot_id, name); + if (sdev) + return sdev; + + mutex_lock(&scmi_syspower_mtx); + if (prot_id == SCMI_PROTOCOL_SYSTEM && scmi_syspower_registered) { + dev_warn(info->dev, + "SCMI SystemPower protocol device must be unique !\n"); + mutex_unlock(&scmi_syspower_mtx); + + return NULL; + } + + pr_debug("Creating SCMI device (%s) for protocol %x\n", name, prot_id); + + sdev = scmi_device_create(np, info->dev, prot_id, name); + if (!sdev) { + dev_err(info->dev, "failed to create %d protocol device\n", + prot_id); + mutex_unlock(&scmi_syspower_mtx); + + return NULL; + } + + if (scmi_txrx_setup(info, &sdev->dev, prot_id)) { + dev_err(&sdev->dev, "failed to setup transport\n"); + scmi_device_destroy(sdev); + mutex_unlock(&scmi_syspower_mtx); + + return NULL; + } + + if (prot_id == SCMI_PROTOCOL_SYSTEM) + scmi_syspower_registered = true; + + mutex_unlock(&scmi_syspower_mtx); + + return sdev; +} + +static inline void +scmi_create_protocol_device(struct device_node *np, struct scmi_info *info, + int prot_id, const char *name) +{ + struct scmi_device *sdev; + + sdev = scmi_get_protocol_device(np, info, prot_id, name); + if (!sdev) + return; + + /* setup handle now as the transport is ready */ + scmi_set_handle(sdev); +} + +/** + * scmi_create_protocol_devices - Create devices for all pending requests for + * this SCMI instance. + * + * @np: The device node describing the protocol + * @info: The SCMI instance descriptor + * @prot_id: The protocol ID + * + * All devices previously requested for this instance (if any) are found and + * created by scanning the proper @&scmi_requested_devices entry. + */ +static void scmi_create_protocol_devices(struct device_node *np, + struct scmi_info *info, int prot_id) +{ + struct list_head *phead; + + mutex_lock(&scmi_requested_devices_mtx); + phead = idr_find(&scmi_requested_devices, prot_id); + if (phead) { + struct scmi_requested_dev *rdev; + + list_for_each_entry(rdev, phead, node) + scmi_create_protocol_device(np, info, prot_id, + rdev->id_table->name); + } + mutex_unlock(&scmi_requested_devices_mtx); +} + +/** + * scmi_protocol_device_request - Helper to request a device + * + * @id_table: A protocol/name pair descriptor for the device to be created. + * + * This helper let an SCMI driver request specific devices identified by the + * @id_table to be created for each active SCMI instance. + * + * The requested device name MUST NOT be already existent for any protocol; + * at first the freshly requested @id_table is annotated in the IDR table + * @scmi_requested_devices, then a matching device is created for each already + * active SCMI instance. (if any) + * + * This way the requested device is created straight-away for all the already + * initialized(probed) SCMI instances (handles) and it remains also annotated + * as pending creation if the requesting SCMI driver was loaded before some + * SCMI instance and related transports were available: when such late instance + * is probed, its probe will take care to scan the list of pending requested + * devices and create those on its own (see @scmi_create_protocol_devices and + * its enclosing loop) + * + * Return: 0 on Success + */ +int scmi_protocol_device_request(const struct scmi_device_id *id_table) +{ + int ret = 0; + unsigned int id = 0; + struct list_head *head, *phead = NULL; + struct scmi_requested_dev *rdev; + struct scmi_info *info; + + pr_debug("Requesting SCMI device (%s) for protocol %x\n", + id_table->name, id_table->protocol_id); + + /* + * Search for the matching protocol rdev list and then search + * of any existent equally named device...fails if any duplicate found. + */ + mutex_lock(&scmi_requested_devices_mtx); + idr_for_each_entry(&scmi_requested_devices, head, id) { + if (!phead) { + /* A list found registered in the IDR is never empty */ + rdev = list_first_entry(head, struct scmi_requested_dev, + node); + if (rdev->id_table->protocol_id == + id_table->protocol_id) + phead = head; + } + list_for_each_entry(rdev, head, node) { + if (!strcmp(rdev->id_table->name, id_table->name)) { + pr_err("Ignoring duplicate request [%d] %s\n", + rdev->id_table->protocol_id, + rdev->id_table->name); + ret = -EINVAL; + goto out; + } + } + } + + /* + * No duplicate found for requested id_table, so let's create a new + * requested device entry for this new valid request. + */ + rdev = kzalloc(sizeof(*rdev), GFP_KERNEL); + if (!rdev) { + ret = -ENOMEM; + goto out; + } + rdev->id_table = id_table; + + /* + * Append the new requested device table descriptor to the head of the + * related protocol list, eventually creating such head if not already + * there. + */ + if (!phead) { + phead = kzalloc(sizeof(*phead), GFP_KERNEL); + if (!phead) { + kfree(rdev); + ret = -ENOMEM; + goto out; + } + INIT_LIST_HEAD(phead); + + ret = idr_alloc(&scmi_requested_devices, (void *)phead, + id_table->protocol_id, + id_table->protocol_id + 1, GFP_KERNEL); + if (ret != id_table->protocol_id) { + pr_err("Failed to save SCMI device - ret:%d\n", ret); + kfree(rdev); + kfree(phead); + ret = -EINVAL; + goto out; + } + ret = 0; + } + list_add(&rdev->node, phead); + + /* + * Now effectively create and initialize the requested device for every + * already initialized SCMI instance which has registered the requested + * protocol as a valid active one: i.e. defined in DT and supported by + * current platform FW. + */ + mutex_lock(&scmi_list_mutex); + list_for_each_entry(info, &scmi_list, node) { + struct device_node *child; + + child = idr_find(&info->active_protocols, + id_table->protocol_id); + if (child) { + struct scmi_device *sdev; + + sdev = scmi_get_protocol_device(child, info, + id_table->protocol_id, + id_table->name); + if (sdev) { + /* Set handle if not already set: device existed */ + if (!sdev->handle) + sdev->handle = + scmi_handle_get_from_info_unlocked(info); + /* Relink consumer and suppliers */ + if (sdev->handle) + scmi_device_link_add(&sdev->dev, + sdev->handle->dev); + } + } else { + dev_err(info->dev, + "Failed. SCMI protocol %d not active.\n", + id_table->protocol_id); + } + } + mutex_unlock(&scmi_list_mutex); + +out: + mutex_unlock(&scmi_requested_devices_mtx); + + return ret; +} + +/** + * scmi_protocol_device_unrequest - Helper to unrequest a device + * + * @id_table: A protocol/name pair descriptor for the device to be unrequested. + * + * An helper to let an SCMI driver release its request about devices; note that + * devices are created and initialized once the first SCMI driver request them + * but they destroyed only on SCMI core unloading/unbinding. + * + * The current SCMI transport layer uses such devices as internal references and + * as such they could be shared as same transport between multiple drivers so + * that cannot be safely destroyed till the whole SCMI stack is removed. + * (unless adding further burden of refcounting.) + */ +void scmi_protocol_device_unrequest(const struct scmi_device_id *id_table) +{ + struct list_head *phead; + + pr_debug("Unrequesting SCMI device (%s) for protocol %x\n", + id_table->name, id_table->protocol_id); + + mutex_lock(&scmi_requested_devices_mtx); + phead = idr_find(&scmi_requested_devices, id_table->protocol_id); + if (phead) { + struct scmi_requested_dev *victim, *tmp; + + list_for_each_entry_safe(victim, tmp, phead, node) { + if (!strcmp(victim->id_table->name, id_table->name)) { + list_del(&victim->node); + kfree(victim); + break; + } + } + + if (list_empty(phead)) { + idr_remove(&scmi_requested_devices, + id_table->protocol_id); + kfree(phead); + } + } + mutex_unlock(&scmi_requested_devices_mtx); +} + +static int scmi_cleanup_txrx_channels(struct scmi_info *info) +{ + int ret; + struct idr *idr = &info->tx_idr; + + ret = idr_for_each(idr, info->desc->ops->chan_free, idr); + idr_destroy(&info->tx_idr); + + idr = &info->rx_idr; + ret = idr_for_each(idr, info->desc->ops->chan_free, idr); + idr_destroy(&info->rx_idr); + + return ret; +} + +static int scmi_probe(struct platform_device *pdev) +{ + int ret; + struct scmi_handle *handle; + const struct scmi_desc *desc; + struct scmi_info *info; + struct device *dev = &pdev->dev; + struct device_node *child, *np = dev->of_node; + + desc = of_device_get_match_data(dev); + if (!desc) + return -EINVAL; + + info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL); + if (!info) + return -ENOMEM; + + info->dev = dev; + info->desc = desc; + INIT_LIST_HEAD(&info->node); + idr_init(&info->protocols); + mutex_init(&info->protocols_mtx); + idr_init(&info->active_protocols); + + platform_set_drvdata(pdev, info); + idr_init(&info->tx_idr); + idr_init(&info->rx_idr); + + handle = &info->handle; + handle->dev = info->dev; + handle->version = &info->version; + handle->devm_protocol_acquire = scmi_devm_protocol_acquire; + handle->devm_protocol_get = scmi_devm_protocol_get; + handle->devm_protocol_put = scmi_devm_protocol_put; + + /* System wide atomic threshold for atomic ops .. if any */ + if (!of_property_read_u32(np, "atomic-threshold-us", + &info->atomic_threshold)) + dev_info(dev, + "SCMI System wide atomic threshold set to %d us\n", + info->atomic_threshold); + handle->is_transport_atomic = scmi_is_transport_atomic; + + if (desc->ops->link_supplier) { + ret = desc->ops->link_supplier(dev); + if (ret) + return ret; + } + + ret = scmi_txrx_setup(info, dev, SCMI_PROTOCOL_BASE); + if (ret) + return ret; + + ret = scmi_xfer_info_init(info); + if (ret) + goto clear_txrx_setup; + + if (scmi_notification_init(handle)) + dev_err(dev, "SCMI Notifications NOT available.\n"); + + if (info->desc->atomic_enabled && !is_transport_polling_capable(info)) + dev_err(dev, + "Transport is not polling capable. Atomic mode not supported.\n"); + + /* + * Trigger SCMI Base protocol initialization. + * It's mandatory and won't be ever released/deinit until the + * SCMI stack is shutdown/unloaded as a whole. + */ + ret = scmi_protocol_acquire(handle, SCMI_PROTOCOL_BASE); + if (ret) { + dev_err(dev, "unable to communicate with SCMI\n"); + goto notification_exit; + } + + mutex_lock(&scmi_list_mutex); + list_add_tail(&info->node, &scmi_list); + mutex_unlock(&scmi_list_mutex); + + for_each_available_child_of_node(np, child) { + u32 prot_id; + + if (of_property_read_u32(child, "reg", &prot_id)) + continue; + + if (!FIELD_FIT(MSG_PROTOCOL_ID_MASK, prot_id)) + dev_err(dev, "Out of range protocol %d\n", prot_id); + + if (!scmi_is_protocol_implemented(handle, prot_id)) { + dev_err(dev, "SCMI protocol %d not implemented\n", + prot_id); + continue; + } + + /* + * Save this valid DT protocol descriptor amongst + * @active_protocols for this SCMI instance/ + */ + ret = idr_alloc(&info->active_protocols, child, + prot_id, prot_id + 1, GFP_KERNEL); + if (ret != prot_id) { + dev_err(dev, "SCMI protocol %d already activated. Skip\n", + prot_id); + continue; + } + + of_node_get(child); + scmi_create_protocol_devices(child, info, prot_id); + } + + return 0; + +notification_exit: + scmi_notification_exit(&info->handle); +clear_txrx_setup: + scmi_cleanup_txrx_channels(info); + return ret; +} + +void scmi_free_channel(struct scmi_chan_info *cinfo, struct idr *idr, int id) +{ + idr_remove(idr, id); +} + +static int scmi_remove(struct platform_device *pdev) +{ + int ret, id; + struct scmi_info *info = platform_get_drvdata(pdev); + struct device_node *child; + + mutex_lock(&scmi_list_mutex); + if (info->users) + dev_warn(&pdev->dev, + "Still active SCMI users will be forcibly unbound.\n"); + list_del(&info->node); + mutex_unlock(&scmi_list_mutex); + + scmi_notification_exit(&info->handle); + + mutex_lock(&info->protocols_mtx); + idr_destroy(&info->protocols); + mutex_unlock(&info->protocols_mtx); + + idr_for_each_entry(&info->active_protocols, child, id) + of_node_put(child); + idr_destroy(&info->active_protocols); + + /* Safe to free channels since no more users */ + ret = scmi_cleanup_txrx_channels(info); + if (ret) + dev_warn(&pdev->dev, "Failed to cleanup SCMI channels.\n"); + + return 0; +} + +static ssize_t protocol_version_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct scmi_info *info = dev_get_drvdata(dev); + + return sprintf(buf, "%u.%u\n", info->version.major_ver, + info->version.minor_ver); +} +static DEVICE_ATTR_RO(protocol_version); + +static ssize_t firmware_version_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct scmi_info *info = dev_get_drvdata(dev); + + return sprintf(buf, "0x%x\n", info->version.impl_ver); +} +static DEVICE_ATTR_RO(firmware_version); + +static ssize_t vendor_id_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct scmi_info *info = dev_get_drvdata(dev); + + return sprintf(buf, "%s\n", info->version.vendor_id); +} +static DEVICE_ATTR_RO(vendor_id); + +static ssize_t sub_vendor_id_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct scmi_info *info = dev_get_drvdata(dev); + + return sprintf(buf, "%s\n", info->version.sub_vendor_id); +} +static DEVICE_ATTR_RO(sub_vendor_id); + +static struct attribute *versions_attrs[] = { + &dev_attr_firmware_version.attr, + &dev_attr_protocol_version.attr, + &dev_attr_vendor_id.attr, + &dev_attr_sub_vendor_id.attr, + NULL, +}; +ATTRIBUTE_GROUPS(versions); + +/* Each compatible listed below must have descriptor associated with it */ +static const struct of_device_id scmi_of_match[] = { +#ifdef CONFIG_ARM_SCMI_TRANSPORT_MAILBOX + { .compatible = "arm,scmi", .data = &scmi_mailbox_desc }, +#endif +#ifdef CONFIG_ARM_SCMI_TRANSPORT_OPTEE + { .compatible = "linaro,scmi-optee", .data = &scmi_optee_desc }, +#endif +#ifdef CONFIG_ARM_SCMI_TRANSPORT_SMC + { .compatible = "arm,scmi-smc", .data = &scmi_smc_desc}, +#endif +#ifdef CONFIG_ARM_SCMI_TRANSPORT_VIRTIO + { .compatible = "arm,scmi-virtio", .data = &scmi_virtio_desc}, +#endif + { /* Sentinel */ }, +}; + +MODULE_DEVICE_TABLE(of, scmi_of_match); + +static struct platform_driver scmi_driver = { + .driver = { + .name = "arm-scmi", + .suppress_bind_attrs = true, + .of_match_table = scmi_of_match, + .dev_groups = versions_groups, + }, + .probe = scmi_probe, + .remove = scmi_remove, +}; + +/** + * __scmi_transports_setup - Common helper to call transport-specific + * .init/.exit code if provided. + * + * @init: A flag to distinguish between init and exit. + * + * Note that, if provided, we invoke .init/.exit functions for all the + * transports currently compiled in. + * + * Return: 0 on Success. + */ +static inline int __scmi_transports_setup(bool init) +{ + int ret = 0; + const struct of_device_id *trans; + + for (trans = scmi_of_match; trans->data; trans++) { + const struct scmi_desc *tdesc = trans->data; + + if ((init && !tdesc->transport_init) || + (!init && !tdesc->transport_exit)) + continue; + + if (init) + ret = tdesc->transport_init(); + else + tdesc->transport_exit(); + + if (ret) { + pr_err("SCMI transport %s FAILED initialization!\n", + trans->compatible); + break; + } + } + + return ret; +} + +static int __init scmi_transports_init(void) +{ + return __scmi_transports_setup(true); +} + +static void __exit scmi_transports_exit(void) +{ + __scmi_transports_setup(false); +} + +static int __init scmi_driver_init(void) +{ + int ret; + + /* Bail out if no SCMI transport was configured */ + if (WARN_ON(!IS_ENABLED(CONFIG_ARM_SCMI_HAVE_TRANSPORT))) + return -EINVAL; + + scmi_bus_init(); + + /* Initialize any compiled-in transport which provided an init/exit */ + ret = scmi_transports_init(); + if (ret) + return ret; + + scmi_base_register(); + + scmi_clock_register(); + scmi_perf_register(); + scmi_power_register(); + scmi_reset_register(); + scmi_sensors_register(); + scmi_voltage_register(); + scmi_system_register(); + scmi_powercap_register(); + + return platform_driver_register(&scmi_driver); +} +subsys_initcall(scmi_driver_init); + +static void __exit scmi_driver_exit(void) +{ + scmi_base_unregister(); + + scmi_clock_unregister(); + scmi_perf_unregister(); + scmi_power_unregister(); + scmi_reset_unregister(); + scmi_sensors_unregister(); + scmi_voltage_unregister(); + scmi_system_unregister(); + scmi_powercap_unregister(); + + scmi_bus_exit(); + + scmi_transports_exit(); + + platform_driver_unregister(&scmi_driver); +} +module_exit(scmi_driver_exit); + +MODULE_ALIAS("platform:arm-scmi"); +MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); +MODULE_DESCRIPTION("ARM SCMI protocol driver"); +MODULE_LICENSE("GPL v2"); |