// 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 #include #include #include #include #include #include #include #include #include #include "common.h" #define CREATE_TRACE_POINTS #include 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); /* Track the unique id for the transfers for debug & profiling purpose */ static atomic_t transfer_last_id; /** * 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; spinlock_t xfer_lock; }; /** * 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 * @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_imp: List of protocols implemented, currently maximum of * MAX_PROTOCOLS_IMP elements allocated by the base protocol * @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 idr tx_idr; struct idr rx_idr; u8 *protocols_imp; 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) { 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, "Message ID: %x Sequence ID: %x Protocol: %x\n", hdr->id, hdr->seq, hdr->protocol_id); } /** * scmi_xfer_get() - Allocate one message * * @handle: Pointer to SCMI entity handle * @minfo: Pointer to Tx/Rx Message management info based on channel type * * Helper function which is used by various message 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_xfer_get(const struct scmi_handle *handle, struct scmi_xfers_info *minfo) { u16 xfer_id; struct scmi_xfer *xfer; unsigned long flags, bit_pos; struct scmi_info *info = handle_to_scmi_info(handle); /* 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); xfer->transfer_id = atomic_inc_return(&transfer_last_id); 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 * * 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; /* * 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_rx_callback() - callback for receiving messages * * @cinfo: SCMI channel info * @msg_hdr: Message header * * 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) { struct scmi_info *info = handle_to_scmi_info(cinfo->handle); struct scmi_xfers_info *minfo = &info->tx_minfo; u16 xfer_id = MSG_XTRACT_TOKEN(msg_hdr); u8 msg_type = MSG_XTRACT_TYPE(msg_hdr); struct device *dev = cinfo->dev; struct scmi_xfer *xfer; if (msg_type == MSG_TYPE_NOTIFICATION) return; /* Notifications not yet supported */ /* 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); info->desc->ops->fetch_response(cinfo, xfer); trace_scmi_rx_done(xfer->transfer_id, xfer->hdr.id, xfer->hdr.protocol_id, xfer->hdr.seq, msg_type); if (msg_type == MSG_TYPE_DELAYED_RESP) complete(xfer->async_done); else complete(&xfer->done); } /** * scmi_xfer_put() - Release a transmit message * * @handle: Pointer to SCMI entity handle * @xfer: message that was reserved by scmi_xfer_get */ void scmi_xfer_put(const struct scmi_handle *handle, struct scmi_xfer *xfer) { struct scmi_info *info = handle_to_scmi_info(handle); __scmi_xfer_put(&info->tx_minfo, xfer); } #define SCMI_MAX_POLL_TO_NS (100 * NSEC_PER_USEC) 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); return info->desc->ops->poll_done(cinfo, xfer) || ktime_after(ktime_get(), stop); } /** * scmi_do_xfer() - Do one transfer * * @handle: Pointer to SCMI entity 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. */ 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; struct scmi_chan_info *cinfo; cinfo = idr_find(&info->tx_idr, xfer->hdr.protocol_id); if (unlikely(!cinfo)) return -EINVAL; trace_scmi_xfer_begin(xfer->transfer_id, xfer->hdr.id, xfer->hdr.protocol_id, xfer->hdr.seq, xfer->hdr.poll_completion); ret = info->desc->ops->send_message(cinfo, xfer); if (ret < 0) { dev_dbg(dev, "Failed to send message %d\n", ret); return ret; } if (xfer->hdr.poll_completion) { ktime_t stop = ktime_add_ns(ktime_get(), SCMI_MAX_POLL_TO_NS); spin_until_cond(scmi_xfer_done_no_timeout(cinfo, xfer, stop)); if (ktime_before(ktime_get(), stop)) info->desc->ops->fetch_response(cinfo, xfer); else ret = -ETIMEDOUT; } else { /* 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, "timed out in resp(caller: %pS)\n", (void *)_RET_IP_); ret = -ETIMEDOUT; } } 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); trace_scmi_xfer_end(xfer->transfer_id, xfer->hdr.id, xfer->hdr.protocol_id, xfer->hdr.seq, xfer->hdr.status); return ret; } #define SCMI_MAX_RESPONSE_TIMEOUT (2 * MSEC_PER_SEC) /** * scmi_do_xfer_with_response() - Do one transfer and wait until the delayed * response is received * * @handle: Pointer to SCMI entity handle * @xfer: Transfer to initiate and wait for response * * Return: -ETIMEDOUT in case of no delayed response, if transmit error, * return corresponding error, else if all goes well, return 0. */ int scmi_do_xfer_with_response(const struct scmi_handle *handle, struct scmi_xfer *xfer) { int ret, timeout = msecs_to_jiffies(SCMI_MAX_RESPONSE_TIMEOUT); DECLARE_COMPLETION_ONSTACK(async_response); xfer->async_done = &async_response; ret = scmi_do_xfer(handle, xfer); if (!ret && !wait_for_completion_timeout(xfer->async_done, timeout)) ret = -ETIMEDOUT; xfer->async_done = NULL; return ret; } /** * scmi_xfer_get_init() - Allocate and initialise one message for transmit * * @handle: Pointer to SCMI entity handle * @msg_id: Message identifier * @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_xfer_get and * initialise the header. * * Return: 0 if all went fine with @p pointing to message, else * corresponding error. */ int scmi_xfer_get_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 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(handle, minfo); 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_version_get() - command to get the revision of the SCMI entity * * @handle: Pointer to SCMI entity handle * @protocol: Protocol identifier for the message * @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. */ int scmi_version_get(const struct scmi_handle *handle, u8 protocol, u32 *version) { int ret; __le32 *rev_info; struct scmi_xfer *t; ret = scmi_xfer_get_init(handle, PROTOCOL_VERSION, protocol, 0, sizeof(*version), &t); if (ret) return ret; ret = scmi_do_xfer(handle, t); if (!ret) { rev_info = t->rx.buf; *version = le32_to_cpu(*rev_info); } scmi_xfer_put(handle, t); return ret; } void scmi_setup_protocol_implemented(const struct scmi_handle *handle, u8 *prot_imp) { struct scmi_info *info = handle_to_scmi_info(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); if (!info->protocols_imp) return false; for (i = 0; i < MAX_PROTOCOLS_IMP; i++) if (info->protocols_imp[i] == prot_id) return true; return false; } /** * 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 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->tx_minfo; /* Pre-allocated messages, no more than what hdr.seq can support */ if (WARN_ON(desc->max_msg >= MSG_TOKEN_MAX)) { dev_err(dev, "Maximum message of %d exceeds supported %ld\n", desc->max_msg, MSG_TOKEN_MAX); 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; /* 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_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; ret = info->desc->ops->chan_setup(cinfo, info->dev, tx); if (ret) return ret; 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, hence no error check */ scmi_chan_setup(info, dev, prot_id, false); return ret; } 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_device_create(np, info->dev, prot_id, name); if (!sdev) { dev_err(info->dev, "failed to create %d protocol device\n", prot_id); return; } if (scmi_txrx_setup(info, &sdev->dev, prot_id)) { dev_err(&sdev->dev, "failed to setup transport\n"); scmi_device_destroy(sdev); return; } /* setup handle now as the transport is ready */ scmi_set_handle(sdev); } #define MAX_SCMI_DEV_PER_PROTOCOL 2 struct scmi_prot_devnames { int protocol_id; char *names[MAX_SCMI_DEV_PER_PROTOCOL]; }; static struct scmi_prot_devnames devnames[] = { { SCMI_PROTOCOL_POWER, { "genpd" },}, { SCMI_PROTOCOL_PERF, { "cpufreq" },}, { SCMI_PROTOCOL_CLOCK, { "clocks" },}, { SCMI_PROTOCOL_SENSOR, { "hwmon" },}, { SCMI_PROTOCOL_RESET, { "reset" },}, }; static inline void scmi_create_protocol_devices(struct device_node *np, struct scmi_info *info, int prot_id) { int loop, cnt; for (loop = 0; loop < ARRAY_SIZE(devnames); loop++) { if (devnames[loop].protocol_id != prot_id) continue; for (cnt = 0; cnt < ARRAY_SIZE(devnames[loop].names); cnt++) { const char *name = devnames[loop].names[cnt]; if (name) scmi_create_protocol_device(np, info, prot_id, name); } } } 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); ret = scmi_xfer_info_init(info); if (ret) return ret; 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; ret = scmi_txrx_setup(info, dev, SCMI_PROTOCOL_BASE); if (ret) return ret; ret = scmi_base_protocol_init(handle); if (ret) { dev_err(dev, "unable to communicate with SCMI(%d)\n", ret); return ret; } 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; } scmi_create_protocol_devices(child, info, prot_id); } return 0; } 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 = 0; struct scmi_info *info = platform_get_drvdata(pdev); struct idr *idr = &info->tx_idr; mutex_lock(&scmi_list_mutex); if (info->users) ret = -EBUSY; else list_del(&info->node); mutex_unlock(&scmi_list_mutex); if (ret) return ret; /* Safe to free channels since no more users */ 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 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[] = { { .compatible = "arm,scmi", .data = &scmi_mailbox_desc }, { /* Sentinel */ }, }; MODULE_DEVICE_TABLE(of, scmi_of_match); static struct platform_driver scmi_driver = { .driver = { .name = "arm-scmi", .of_match_table = scmi_of_match, .dev_groups = versions_groups, }, .probe = scmi_probe, .remove = scmi_remove, }; module_platform_driver(scmi_driver); MODULE_ALIAS("platform: arm-scmi"); MODULE_AUTHOR("Sudeep Holla "); MODULE_DESCRIPTION("ARM SCMI protocol driver"); MODULE_LICENSE("GPL v2");