diff options
Diffstat (limited to 'drivers/firmware/arm_scmi/driver.c')
| -rw-r--r-- | drivers/firmware/arm_scmi/driver.c | 678 |
1 files changed, 678 insertions, 0 deletions
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c new file mode 100644 index 000000000000..7824cce54373 --- /dev/null +++ b/drivers/firmware/arm_scmi/driver.c @@ -0,0 +1,678 @@ +// 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 ARM Ltd. + */ + +#include <linux/bitmap.h> +#include <linux/export.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/mailbox_client.h> +#include <linux/module.h> +#include <linux/of_address.h> +#include <linux/of_device.h> +#include <linux/semaphore.h> +#include <linux/slab.h> + +#include "common.h" + +#define MSG_ID_SHIFT 0 +#define MSG_ID_MASK 0xff +#define MSG_TYPE_SHIFT 8 +#define MSG_TYPE_MASK 0x3 +#define MSG_PROTOCOL_ID_SHIFT 10 +#define MSG_PROTOCOL_ID_MASK 0xff +#define MSG_TOKEN_ID_SHIFT 18 +#define MSG_TOKEN_ID_MASK 0x3ff +#define MSG_XTRACT_TOKEN(header) \ + (((header) >> MSG_TOKEN_ID_SHIFT) & MSG_TOKEN_ID_MASK) + +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 */ + SCMI_ERR_MAX +}; + +/* List of all SCMI devices active in system */ +static LIST_HEAD(scmi_list); +/* Protection for the entire list */ +static DEFINE_MUTEX(scmi_list_mutex); + +/** + * struct scmi_xfers_info - Structure to manage transfer information + * + * @xfer_block: Preallocated Message array + * @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 + */ +struct scmi_xfers_info { + struct scmi_xfer *xfer_block; + unsigned long *xfer_alloc_table; + /* protect transfer allocation */ + spinlock_t xfer_lock; +}; + +/** + * struct scmi_desc - Description of SoC integration + * + * @max_rx_timeout_ms: Timeout for communication with SoC (in Milliseconds) + * @max_msg: Maximum number of messages that can be pending + * simultaneously in the system + * @max_msg_size: Maximum size of data per message that can be handled. + */ +struct scmi_desc { + int max_rx_timeout_ms; + int max_msg; + int max_msg_size; +}; + +/** + * struct scmi_info - Structure representing a SCMI instance + * + * @dev: Device pointer + * @desc: SoC description for this instance + * @handle: Instance of SCMI handle to send to clients + * @cl: Mailbox Client + * @tx_chan: Transmit mailbox channel + * @tx_payload: Transmit mailbox channel payload area + * @minfo: Message info + * @node: list head + * @users: Number of users of this instance + */ +struct scmi_info { + struct device *dev; + const struct scmi_desc *desc; + struct scmi_handle handle; + struct mbox_client cl; + struct mbox_chan *tx_chan; + void __iomem *tx_payload; + struct scmi_xfers_info minfo; + struct list_head node; + int users; +}; + +#define client_to_scmi_info(c) container_of(c, struct scmi_info, cl) +#define handle_to_scmi_info(h) container_of(h, struct scmi_info, handle) + +/* + * SCMI specification requires all parameters, message headers, return + * arguments or any protocol data to be expressed in little endian + * format only. + */ +struct scmi_shared_mem { + __le32 reserved; + __le32 channel_status; +#define SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR BIT(1) +#define SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE BIT(0) + __le32 reserved1[2]; + __le32 flags; +#define SCMI_SHMEM_FLAG_INTR_ENABLED BIT(0) + __le32 length; + __le32 msg_header; + u8 msg_payload[0]; +}; + +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) +{ + if (errno < SCMI_SUCCESS && errno > SCMI_ERR_MAX) + return scmi_linux_errmap[-errno]; + return -EIO; +} + +/** + * scmi_dump_header_dbg() - Helper to dump a message header. + * + * @dev: Device pointer corresponding to the SCMI entity + * @hdr: pointer to header. + */ +static inline void scmi_dump_header_dbg(struct device *dev, + struct scmi_msg_hdr *hdr) +{ + dev_dbg(dev, "Command ID: %x Sequence ID: %x Protocol: %x\n", + hdr->id, hdr->seq, hdr->protocol_id); +} + +static void scmi_fetch_response(struct scmi_xfer *xfer, + struct scmi_shared_mem __iomem *mem) +{ + xfer->hdr.status = ioread32(mem->msg_payload); + /* Skip the length of header and statues in payload area i.e 8 bytes*/ + xfer->rx.len = min_t(size_t, xfer->rx.len, ioread32(&mem->length) - 8); + + /* Take a copy to the rx buffer.. */ + memcpy_fromio(xfer->rx.buf, mem->msg_payload + 4, xfer->rx.len); +} + +/** + * scmi_rx_callback() - mailbox client callback for receive messages + * + * @cl: client pointer + * @m: mailbox message + * + * 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. + */ +static void scmi_rx_callback(struct mbox_client *cl, void *m) +{ + u16 xfer_id; + struct scmi_xfer *xfer; + struct scmi_info *info = client_to_scmi_info(cl); + struct scmi_xfers_info *minfo = &info->minfo; + struct device *dev = info->dev; + struct scmi_shared_mem __iomem *mem = info->tx_payload; + + xfer_id = MSG_XTRACT_TOKEN(ioread32(&mem->msg_header)); + + /* + * Are we even expecting this? + */ + if (!test_bit(xfer_id, minfo->xfer_alloc_table)) { + dev_err(dev, "message for %d is not expected!\n", xfer_id); + return; + } + + xfer = &minfo->xfer_block[xfer_id]; + + scmi_dump_header_dbg(dev, &xfer->hdr); + /* Is the message of valid length? */ + if (xfer->rx.len > info->desc->max_msg_size) { + dev_err(dev, "unable to handle %zu xfer(max %d)\n", + xfer->rx.len, info->desc->max_msg_size); + return; + } + + scmi_fetch_response(xfer, mem); + complete(&xfer->done); +} + +/** + * pack_scmi_header() - packs and returns 32-bit header + * + * @hdr: pointer to header containing all the information on message id, + * protocol id and sequence id. + */ +static inline u32 pack_scmi_header(struct scmi_msg_hdr *hdr) +{ + return ((hdr->id & MSG_ID_MASK) << MSG_ID_SHIFT) | + ((hdr->seq & MSG_TOKEN_ID_MASK) << MSG_TOKEN_ID_SHIFT) | + ((hdr->protocol_id & MSG_PROTOCOL_ID_MASK) << MSG_PROTOCOL_ID_SHIFT); +} + +/** + * scmi_tx_prepare() - mailbox client callback to prepare for the transfer + * + * @cl: client pointer + * @m: mailbox message + * + * This function prepares the shared memory which contains the header and the + * payload. + */ +static void scmi_tx_prepare(struct mbox_client *cl, void *m) +{ + struct scmi_xfer *t = m; + struct scmi_info *info = client_to_scmi_info(cl); + struct scmi_shared_mem __iomem *mem = info->tx_payload; + + /* Mark channel busy + clear error */ + iowrite32(0x0, &mem->channel_status); + iowrite32(t->hdr.poll_completion ? 0 : SCMI_SHMEM_FLAG_INTR_ENABLED, + &mem->flags); + iowrite32(sizeof(mem->msg_header) + t->tx.len, &mem->length); + iowrite32(pack_scmi_header(&t->hdr), &mem->msg_header); + if (t->tx.buf) + memcpy_toio(mem->msg_payload, t->tx.buf, t->tx.len); +} + +/** + * scmi_one_xfer_get() - Allocate one message + * + * @handle: SCMI entity handle + * + * Helper function which is used by various command functions that are + * exposed to clients of this driver for allocating a message traffic event. + * + * This function can sleep depending on pending requests already in the system + * for the SCMI entity. Further, this also holds a spinlock to maintain + * integrity of internal data structures. + * + * Return: 0 if all went fine, else corresponding error. + */ +static struct scmi_xfer *scmi_one_xfer_get(const struct scmi_handle *handle) +{ + u16 xfer_id; + struct scmi_xfer *xfer; + unsigned long flags, bit_pos; + struct scmi_info *info = handle_to_scmi_info(handle); + struct scmi_xfers_info *minfo = &info->minfo; + + /* Keep the locked section as small as possible */ + spin_lock_irqsave(&minfo->xfer_lock, flags); + bit_pos = find_first_zero_bit(minfo->xfer_alloc_table, + info->desc->max_msg); + if (bit_pos == info->desc->max_msg) { + spin_unlock_irqrestore(&minfo->xfer_lock, flags); + return ERR_PTR(-ENOMEM); + } + set_bit(bit_pos, minfo->xfer_alloc_table); + spin_unlock_irqrestore(&minfo->xfer_lock, flags); + + xfer_id = bit_pos; + + xfer = &minfo->xfer_block[xfer_id]; + xfer->hdr.seq = xfer_id; + reinit_completion(&xfer->done); + + return xfer; +} + +/** + * scmi_one_xfer_put() - Release a message + * + * @minfo: transfer info pointer + * @xfer: message that was reserved by scmi_one_xfer_get + * + * This holds a spinlock to maintain integrity of internal data structures. + */ +void scmi_one_xfer_put(const struct scmi_handle *handle, struct scmi_xfer *xfer) +{ + unsigned long flags; + struct scmi_info *info = handle_to_scmi_info(handle); + struct scmi_xfers_info *minfo = &info->minfo; + + /* + * Keep the locked section as small as possible + * NOTE: we might escape with smp_mb and no lock here.. + * but just be conservative and symmetric. + */ + spin_lock_irqsave(&minfo->xfer_lock, flags); + clear_bit(xfer->hdr.seq, minfo->xfer_alloc_table); + spin_unlock_irqrestore(&minfo->xfer_lock, flags); +} + +/** + * scmi_do_xfer() - Do one transfer + * + * @info: Pointer to SCMI entity information + * @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. + */ +int scmi_do_xfer(const struct scmi_handle *handle, struct scmi_xfer *xfer) +{ + int ret; + int timeout; + struct scmi_info *info = handle_to_scmi_info(handle); + struct device *dev = info->dev; + + ret = mbox_send_message(info->tx_chan, xfer); + if (ret < 0) { + dev_dbg(dev, "mbox send fail %d\n", ret); + return ret; + } + + /* mbox_send_message returns non-negative value on success, so reset */ + ret = 0; + + /* And we wait for the response. */ + timeout = msecs_to_jiffies(info->desc->max_rx_timeout_ms); + if (!wait_for_completion_timeout(&xfer->done, timeout)) { + dev_err(dev, "mbox timed out in resp(caller: %pS)\n", + (void *)_RET_IP_); + ret = -ETIMEDOUT; + } else if (xfer->hdr.status) { + ret = scmi_to_linux_errno(xfer->hdr.status); + } + /* + * NOTE: we might prefer not to need the mailbox ticker to manage the + * transfer queueing since the protocol layer queues things by itself. + * Unfortunately, we have to kick the mailbox framework after we have + * received our message. + */ + mbox_client_txdone(info->tx_chan, ret); + + return ret; +} + +/** + * scmi_one_xfer_init() - Allocate and initialise one message + * + * @handle: SCMI entity handle + * @msg_id: Message identifier + * @msg_prot_id: Protocol identifier for the message + * @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_one_xfer_get and + * initialise the header. + * + * Return: 0 if all went fine with @p pointing to message, else + * corresponding error. + */ +int scmi_one_xfer_init(const struct scmi_handle *handle, u8 msg_id, u8 prot_id, + size_t tx_size, size_t rx_size, struct scmi_xfer **p) +{ + int ret; + struct scmi_xfer *xfer; + struct scmi_info *info = handle_to_scmi_info(handle); + 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_one_xfer_get(handle); + 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.id = msg_id; + xfer->hdr.protocol_id = prot_id; + xfer->hdr.poll_completion = false; + + *p = xfer; + return 0; +} + +/** + * 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 = &info->handle; + info->users++; + 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 const struct scmi_desc scmi_generic_desc = { + .max_rx_timeout_ms = 30, /* we may increase this if required */ + .max_msg = 20, /* Limited by MBOX_TX_QUEUE_LEN */ + .max_msg_size = 128, +}; + +/* Each compatible listed below must have descriptor associated with it */ +static const struct of_device_id scmi_of_match[] = { + { .compatible = "arm,scmi", .data = &scmi_generic_desc }, + { /* Sentinel */ }, +}; + +MODULE_DEVICE_TABLE(of, scmi_of_match); + +static int scmi_xfer_info_init(struct scmi_info *sinfo) +{ + int i; + struct scmi_xfer *xfer; + struct device *dev = sinfo->dev; + const struct scmi_desc *desc = sinfo->desc; + struct scmi_xfers_info *info = &sinfo->minfo; + + /* Pre-allocated messages, no more than what hdr.seq can support */ + if (WARN_ON(desc->max_msg >= (MSG_TOKEN_ID_MASK + 1))) { + dev_err(dev, "Maximum message of %d exceeds supported %d\n", + desc->max_msg, MSG_TOKEN_ID_MASK + 1); + return -EINVAL; + } + + info->xfer_block = devm_kcalloc(dev, desc->max_msg, + sizeof(*info->xfer_block), GFP_KERNEL); + if (!info->xfer_block) + return -ENOMEM; + + info->xfer_alloc_table = devm_kcalloc(dev, BITS_TO_LONGS(desc->max_msg), + sizeof(long), GFP_KERNEL); + if (!info->xfer_alloc_table) + return -ENOMEM; + + bitmap_zero(info->xfer_alloc_table, desc->max_msg); + + /* Pre-initialize the buffer pointer to pre-allocated buffers */ + for (i = 0, xfer = info->xfer_block; i < desc->max_msg; i++, xfer++) { + 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(&info->xfer_lock); + + return 0; +} + +static int scmi_mailbox_check(struct device_node *np) +{ + struct of_phandle_args arg; + + return of_parse_phandle_with_args(np, "mboxes", "#mbox-cells", 0, &arg); +} + +static int scmi_mbox_free_channel(struct scmi_info *info) +{ + if (!IS_ERR_OR_NULL(info->tx_chan)) { + mbox_free_channel(info->tx_chan); + info->tx_chan = NULL; + } + + return 0; +} + +static int scmi_remove(struct platform_device *pdev) +{ + int ret = 0; + struct scmi_info *info = platform_get_drvdata(pdev); + + mutex_lock(&scmi_list_mutex); + if (info->users) + ret = -EBUSY; + else + list_del(&info->node); + mutex_unlock(&scmi_list_mutex); + + if (!ret) + /* Safe to free channels since no more users */ + return scmi_mbox_free_channel(info); + + return ret; +} + +static inline int scmi_mbox_chan_setup(struct scmi_info *info) +{ + int ret; + struct resource res; + resource_size_t size; + struct device *dev = info->dev; + struct device_node *shmem, *np = dev->of_node; + struct mbox_client *cl; + + cl = &info->cl; + cl->dev = dev; + cl->rx_callback = scmi_rx_callback; + cl->tx_prepare = scmi_tx_prepare; + cl->tx_block = false; + cl->knows_txdone = true; + + shmem = of_parse_phandle(np, "shmem", 0); + ret = of_address_to_resource(shmem, 0, &res); + of_node_put(shmem); + if (ret) { + dev_err(dev, "failed to get SCMI Tx payload mem resource\n"); + return ret; + } + + size = resource_size(&res); + info->tx_payload = devm_ioremap(dev, res.start, size); + if (!info->tx_payload) { + dev_err(dev, "failed to ioremap SCMI Tx payload\n"); + return -EADDRNOTAVAIL; + } + + /* Transmit channel is first entry i.e. index 0 */ + info->tx_chan = mbox_request_channel(cl, 0); + if (IS_ERR(info->tx_chan)) { + ret = PTR_ERR(info->tx_chan); + if (ret != -EPROBE_DEFER) + dev_err(dev, "failed to request SCMI Tx mailbox\n"); + return ret; + } + + return 0; +} + +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 *np = dev->of_node; + + /* Only mailbox method supported, check for the presence of one */ + if (scmi_mailbox_check(np)) { + dev_err(dev, "no mailbox found in %pOF\n", np); + return -EINVAL; + } + + desc = of_match_device(scmi_of_match, dev)->data; + + info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL); + if (!info) + return -ENOMEM; + + info->dev = dev; + info->desc = desc; + INIT_LIST_HEAD(&info->node); + + ret = scmi_xfer_info_init(info); + if (ret) + return ret; + + platform_set_drvdata(pdev, info); + + handle = &info->handle; + handle->dev = info->dev; + + ret = scmi_mbox_chan_setup(info); + if (ret) + return ret; + + mutex_lock(&scmi_list_mutex); + list_add_tail(&info->node, &scmi_list); + mutex_unlock(&scmi_list_mutex); + + return 0; +} + +static struct platform_driver scmi_driver = { + .driver = { + .name = "arm-scmi", + .of_match_table = scmi_of_match, + }, + .probe = scmi_probe, + .remove = scmi_remove, +}; + +module_platform_driver(scmi_driver); + +MODULE_ALIAS("platform: arm-scmi"); +MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); +MODULE_DESCRIPTION("ARM SCMI protocol driver"); +MODULE_LICENSE("GPL v2"); |