v4.19.13 snapshot.
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
new file mode 100644
index 0000000..8f952f2
--- /dev/null
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -0,0 +1,871 @@
+// 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/ktime.h>
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/processor.h>
+#include <linux/semaphore.h>
+#include <linux/slab.h>
+
+#include "common.h"
+
+#define MSG_ID_MASK GENMASK(7, 0)
+#define MSG_TYPE_MASK GENMASK(9, 8)
+#define MSG_PROTOCOL_ID_MASK GENMASK(17, 10)
+#define MSG_TOKEN_ID_MASK GENMASK(27, 18)
+#define MSG_XTRACT_TOKEN(hdr) FIELD_GET(MSG_TOKEN_ID_MASK, (hdr))
+#define MSG_TOKEN_MAX (MSG_XTRACT_TOKEN(MSG_TOKEN_ID_MASK) + 1)
+
+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;
+ 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_chan_info - Structure representing a SCMI channel informfation
+ *
+ * @cl: Mailbox Client
+ * @chan: Transmit/Receive mailbox channel
+ * @payload: Transmit/Receive mailbox channel payload area
+ * @dev: Reference to device in the SCMI hierarchy corresponding to this
+ * channel
+ * @handle: Pointer to SCMI entity handle
+ */
+struct scmi_chan_info {
+ struct mbox_client cl;
+ struct mbox_chan *chan;
+ void __iomem *payload;
+ struct device *dev;
+ struct scmi_handle *handle;
+};
+
+/**
+ * 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
+ * @version: SCMI revision information containing protocol version,
+ * implementation version and (sub-)vendor identification.
+ * @minfo: Message info
+ * @tx_idr: IDR object to map protocol id to 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 minfo;
+ struct idr tx_idr;
+ u8 *protocols_imp;
+ struct list_head node;
+ int users;
+};
+
+#define client_to_scmi_chan_info(c) container_of(c, struct scmi_chan_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_chan_info *cinfo = client_to_scmi_chan_info(cl);
+ struct device *dev = cinfo->dev;
+ struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
+ struct scmi_xfers_info *minfo = &info->minfo;
+ struct scmi_shared_mem __iomem *mem = cinfo->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.
+ *
+ * Return: 32-bit packed command header to be sent to the platform.
+ */
+static inline u32 pack_scmi_header(struct scmi_msg_hdr *hdr)
+{
+ return FIELD_PREP(MSG_ID_MASK, hdr->id) |
+ FIELD_PREP(MSG_TOKEN_ID_MASK, hdr->seq) |
+ FIELD_PREP(MSG_PROTOCOL_ID_MASK, hdr->protocol_id);
+}
+
+/**
+ * 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_chan_info *cinfo = client_to_scmi_chan_info(cl);
+ struct scmi_shared_mem __iomem *mem = cinfo->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_xfer_get() - Allocate one message
+ *
+ * @handle: Pointer to 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_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_xfer_put() - Release a message
+ *
+ * @handle: Pointer to SCMI entity handle
+ * @xfer: message that was reserved by scmi_xfer_get
+ *
+ * This holds a spinlock to maintain integrity of internal data structures.
+ */
+void scmi_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);
+}
+
+static bool
+scmi_xfer_poll_done(const struct scmi_chan_info *cinfo, struct scmi_xfer *xfer)
+{
+ struct scmi_shared_mem __iomem *mem = cinfo->payload;
+ u16 xfer_id = MSG_XTRACT_TOKEN(ioread32(&mem->msg_header));
+
+ if (xfer->hdr.seq != xfer_id)
+ return false;
+
+ return ioread32(&mem->channel_status) &
+ (SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR |
+ SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE);
+}
+
+#define SCMI_MAX_POLL_TO_NS (100 * NSEC_PER_USEC)
+
+static bool scmi_xfer_done_no_timeout(const struct scmi_chan_info *cinfo,
+ struct scmi_xfer *xfer, ktime_t stop)
+{
+ ktime_t __cur = ktime_get();
+
+ return scmi_xfer_poll_done(cinfo, xfer) || ktime_after(__cur, 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;
+
+ ret = mbox_send_message(cinfo->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;
+
+ 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))
+ scmi_fetch_response(xfer, cinfo->payload);
+ 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, "mbox 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);
+
+ /*
+ * 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(cinfo->chan, ret);
+
+ return ret;
+}
+
+/**
+ * scmi_xfer_get_init() - Allocate and initialise one message
+ *
+ * @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 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);
+ 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 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_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_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(int id, void *p, void *data)
+{
+ struct scmi_chan_info *cinfo = p;
+ struct idr *idr = data;
+
+ if (!IS_ERR_OR_NULL(cinfo->chan)) {
+ mbox_free_channel(cinfo->chan);
+ cinfo->chan = NULL;
+ }
+
+ idr_remove(idr, id);
+
+ return 0;
+}
+
+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, scmi_mbox_free_channel, idr);
+ idr_destroy(&info->tx_idr);
+
+ return ret;
+}
+
+static inline int
+scmi_mbox_chan_setup(struct scmi_info *info, struct device *dev, int prot_id)
+{
+ int ret;
+ struct resource res;
+ resource_size_t size;
+ struct device_node *shmem, *np = dev->of_node;
+ struct scmi_chan_info *cinfo;
+ struct mbox_client *cl;
+
+ if (scmi_mailbox_check(np)) {
+ cinfo = idr_find(&info->tx_idr, SCMI_PROTOCOL_BASE);
+ goto idr_alloc;
+ }
+
+ cinfo = devm_kzalloc(info->dev, sizeof(*cinfo), GFP_KERNEL);
+ if (!cinfo)
+ return -ENOMEM;
+
+ cinfo->dev = dev;
+
+ cl = &cinfo->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);
+ cinfo->payload = devm_ioremap(info->dev, res.start, size);
+ if (!cinfo->payload) {
+ dev_err(dev, "failed to ioremap SCMI Tx payload\n");
+ return -EADDRNOTAVAIL;
+ }
+
+ /* Transmit channel is first entry i.e. index 0 */
+ cinfo->chan = mbox_request_channel(cl, 0);
+ if (IS_ERR(cinfo->chan)) {
+ ret = PTR_ERR(cinfo->chan);
+ if (ret != -EPROBE_DEFER)
+ dev_err(dev, "failed to request SCMI Tx mailbox\n");
+ return ret;
+ }
+
+idr_alloc:
+ ret = idr_alloc(&info->tx_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 void
+scmi_create_protocol_device(struct device_node *np, struct scmi_info *info,
+ int prot_id)
+{
+ struct scmi_device *sdev;
+
+ sdev = scmi_device_create(np, info->dev, prot_id);
+ if (!sdev) {
+ dev_err(info->dev, "failed to create %d protocol device\n",
+ prot_id);
+ return;
+ }
+
+ if (scmi_mbox_chan_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);
+}
+
+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;
+
+ /* 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);
+ idr_init(&info->tx_idr);
+
+ handle = &info->handle;
+ handle->dev = info->dev;
+ handle->version = &info->version;
+
+ ret = scmi_mbox_chan_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_device(child, info, prot_id);
+ }
+
+ 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");