diff options
Diffstat (limited to 'drivers/scmi-msg/smt.c')
| -rw-r--r-- | drivers/scmi-msg/smt.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/drivers/scmi-msg/smt.c b/drivers/scmi-msg/smt.c new file mode 100644 index 0000000..9b079c7 --- /dev/null +++ b/drivers/scmi-msg/smt.c @@ -0,0 +1,206 @@ +// SPDX-License-Identifier: BSD-3-Clause +/* + * Copyright (c) 2015-2019, Arm Limited and Contributors. All rights reserved. + * Copyright (c) 2019-2020, Linaro Limited + */ +#include <assert.h> +#include <stdbool.h> +#include <stdint.h> +#include <string.h> + +#include <drivers/scmi-msg.h> +#include <drivers/scmi.h> +#include <lib/cassert.h> +#include <lib/mmio.h> +#include <lib/spinlock.h> +#include <lib/utils.h> +#include <plat/common/platform.h> + +#include "common.h" + +/* Legacy SMT/SCMI messages are 128 bytes at most including SMT header */ +#define SCMI_PLAYLOAD_MAX 92U +#define SCMI_PLAYLOAD_U32_MAX (SCMI_PLAYLOAD_MAX / sizeof(uint32_t)) + +/** + * struct smt_header - SMT formatted header for SMT base shared memory transfer + * + * @status: Bit flags, see SMT_STATUS_* + * @flags: Bit flags, see SMT_FLAG_* + * @length: Byte size of message payload (variable) + ::message_header (32bit) + * payload: SCMI message payload data + */ +struct smt_header { + uint32_t reserved0; + uint32_t status; + uint64_t reserved1; + uint32_t flags; + uint32_t length; /* message_header + payload */ + uint32_t message_header; + uint32_t payload[]; +}; + +CASSERT(SCMI_PLAYLOAD_MAX + sizeof(struct smt_header) <= SMT_BUF_SLOT_SIZE, + assert_scmi_message_max_length_fits_in_smt_buffer_slot); + +/* Flag set in smt_header::status when SMT does not contain pending message */ +#define SMT_STATUS_FREE BIT_32(0) +/* Flag set in smt_header::status when SMT reports an error */ +#define SMT_STATUS_ERROR BIT_32(1) + +/* Flag set in smt_header::flags when SMT uses interrupts */ +#define SMT_FLAG_INTR_ENABLED BIT_32(1) + +/* Bit fields packed in smt_header::message_header */ +#define SMT_MSG_ID_MASK GENMASK_32(7, 0) +#define SMT_HDR_MSG_ID(_hdr) ((_hdr) & SMT_MSG_ID_MASK) + +#define SMT_MSG_TYPE_MASK GENMASK_32(9, 8) +#define SMT_HDR_TYPE_ID(_hdr) (((_hdr) & SMT_MSG_TYPE_MASK) >> 8) + +#define SMT_MSG_PROT_ID_MASK GENMASK_32(17, 10) +#define SMT_HDR_PROT_ID(_hdr) (((_hdr) & SMT_MSG_PROT_ID_MASK) >> 10) + +/* + * Provision input message payload buffers for fastcall SMC context entries + * and for interrupt context execution entries. + */ +static uint32_t fast_smc_payload[PLATFORM_CORE_COUNT][SCMI_PLAYLOAD_U32_MAX]; +static uint32_t interrupt_payload[PLATFORM_CORE_COUNT][SCMI_PLAYLOAD_U32_MAX]; + +/* SMP protection on channel access */ +static struct spinlock smt_channels_lock; + +/* If channel is not busy, set busy and return true, otherwise return false */ +static bool channel_set_busy(struct scmi_msg_channel *chan) +{ + bool channel_is_busy; + + spin_lock(&smt_channels_lock); + + channel_is_busy = chan->busy; + + if (!channel_is_busy) { + chan->busy = true; + } + + spin_unlock(&smt_channels_lock); + + return !channel_is_busy; +} + +static void channel_release_busy(struct scmi_msg_channel *chan) +{ + chan->busy = false; +} + +static struct smt_header *channel_to_smt_hdr(struct scmi_msg_channel *chan) +{ + return (struct smt_header *)chan->shm_addr; +} + +/* + * Creates a SCMI message instance in secure memory and pushes it in the SCMI + * message drivers. Message structure contains SCMI protocol meta-data and + * references to input payload in secure memory and output message buffer + * in shared memory. + */ +static void scmi_proccess_smt(unsigned int agent_id, uint32_t *payload_buf) +{ + struct scmi_msg_channel *chan; + struct smt_header *smt_hdr; + size_t in_payload_size; + uint32_t smt_status; + struct scmi_msg msg; + bool error = true; + + chan = plat_scmi_get_channel(agent_id); + if (chan == NULL) { + return; + } + + smt_hdr = channel_to_smt_hdr(chan); + assert(smt_hdr); + + smt_status = __atomic_load_n(&smt_hdr->status, __ATOMIC_RELAXED); + + if (!channel_set_busy(chan)) { + VERBOSE("SCMI channel %u busy", agent_id); + goto out; + } + + in_payload_size = __atomic_load_n(&smt_hdr->length, __ATOMIC_RELAXED) - + sizeof(smt_hdr->message_header); + + if (in_payload_size > SCMI_PLAYLOAD_MAX) { + VERBOSE("SCMI payload too big %zu", in_payload_size); + goto out; + } + + if ((smt_status & (SMT_STATUS_ERROR | SMT_STATUS_FREE)) != 0U) { + VERBOSE("SCMI channel bad status 0x%x", + smt_hdr->status & (SMT_STATUS_ERROR | SMT_STATUS_FREE)); + goto out; + } + + /* Fill message */ + zeromem(&msg, sizeof(msg)); + msg.in = (char *)payload_buf; + msg.in_size = in_payload_size; + msg.out = (char *)smt_hdr->payload; + msg.out_size = chan->shm_size - sizeof(*smt_hdr); + + assert((msg.out != NULL) && (msg.out_size >= sizeof(int32_t))); + + /* Here the payload is copied in secure memory */ + memcpy(msg.in, smt_hdr->payload, in_payload_size); + + msg.protocol_id = SMT_HDR_PROT_ID(smt_hdr->message_header); + msg.message_id = SMT_HDR_MSG_ID(smt_hdr->message_header); + msg.agent_id = agent_id; + + scmi_process_message(&msg); + + /* Update message length with the length of the response message */ + smt_hdr->length = msg.out_size_out + sizeof(smt_hdr->message_header); + + channel_release_busy(chan); + error = false; + +out: + if (error) { + VERBOSE("SCMI error"); + smt_hdr->status |= SMT_STATUS_ERROR | SMT_STATUS_FREE; + } else { + smt_hdr->status |= SMT_STATUS_FREE; + } +} + +void scmi_smt_fastcall_smc_entry(unsigned int agent_id) +{ + scmi_proccess_smt(agent_id, + fast_smc_payload[plat_my_core_pos()]); +} + +void scmi_smt_interrupt_entry(unsigned int agent_id) +{ + scmi_proccess_smt(agent_id, + interrupt_payload[plat_my_core_pos()]); +} + +/* Init a SMT header for a shared memory buffer: state it a free/no-error */ +void scmi_smt_init_agent_channel(struct scmi_msg_channel *chan) +{ + if (chan != NULL) { + struct smt_header *smt_header = channel_to_smt_hdr(chan); + + if (smt_header != NULL) { + memset(smt_header, 0, sizeof(*smt_header)); + smt_header->status = SMT_STATUS_FREE; + + return; + } + } + + panic(); +} |