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|
// 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 CREATE_TRACE_POINTS
#include <trace/events/scmi.h>
#define MSG_ID_MASK GENMASK(7, 0)
#define MSG_XTRACT_ID(hdr) FIELD_GET(MSG_ID_MASK, (hdr))
#define MSG_TYPE_MASK GENMASK(9, 8)
#define MSG_XTRACT_TYPE(hdr) FIELD_GET(MSG_TYPE_MASK, (hdr))
#define MSG_TYPE_COMMAND 0
#define MSG_TYPE_DELAYED_RESP 2
#define MSG_TYPE_NOTIFICATION 3
#define MSG_PROTOCOL_ID_MASK GENMASK(17, 10)
#define MSG_XTRACT_PROT_ID(hdr) FIELD_GET(MSG_PROTOCOL_ID_MASK, (hdr))
#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);
/* 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_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 information
*
* @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
* @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 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, "Message 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 status 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);
}
/**
* 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 message 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);
}
/**
* unpack_scmi_header() - unpacks and records message and protocol id
*
* @msg_hdr: 32-bit packed message header sent from the platform
* @hdr: pointer to header to fetch message and protocol id.
*/
static inline void unpack_scmi_header(u32 msg_hdr, struct scmi_msg_hdr *hdr)
{
hdr->id = MSG_XTRACT_ID(msg_hdr);
hdr->protocol_id = MSG_XTRACT_PROT_ID(msg_hdr);
}
/**
* 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;
/*
* Ideally channel must be free by now unless OS timeout last
* request and platform continued to process the same, wait
* until it releases the shared memory, otherwise we may endup
* overwriting its response with new message payload or vice-versa
*/
spin_until_cond(ioread32(&mem->channel_status) &
SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE);
/* 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
* @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() - 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)
{
u8 msg_type;
u32 msg_hdr;
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->tx_minfo;
struct scmi_shared_mem __iomem *mem = cinfo->payload;
msg_hdr = ioread32(&mem->msg_header);
msg_type = MSG_XTRACT_TYPE(msg_hdr);
xfer_id = MSG_XTRACT_TOKEN(msg_hdr);
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);
scmi_fetch_response(xfer, mem);
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);
}
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;
trace_scmi_xfer_begin(xfer->transfer_id, xfer->hdr.id,
xfer->hdr.protocol_id, xfer->hdr.seq,
xfer->hdr.poll_completion);
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);
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_mailbox_check(struct device_node *np, int idx)
{
return of_parse_phandle_with_args(np, "mboxes", "#mbox-cells",
idx, NULL);
}
static int scmi_mbox_chan_setup(struct scmi_info *info, struct device *dev,
int prot_id, bool tx)
{
int ret, idx;
struct resource res;
resource_size_t size;
struct device_node *shmem, *np = dev->of_node;
struct scmi_chan_info *cinfo;
struct mbox_client *cl;
struct idr *idr;
const char *desc = tx ? "Tx" : "Rx";
/* 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 (scmi_mailbox_check(np, 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;
cl = &cinfo->cl;
cl->dev = dev;
cl->rx_callback = scmi_rx_callback;
cl->tx_prepare = tx ? scmi_tx_prepare : NULL;
cl->tx_block = false;
cl->knows_txdone = tx;
shmem = of_parse_phandle(np, "shmem", idx);
ret = of_address_to_resource(shmem, 0, &res);
of_node_put(shmem);
if (ret) {
dev_err(dev, "failed to get SCMI %s payload memory\n", desc);
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 %s payload\n", desc);
return -EADDRNOTAVAIL;
}
cinfo->chan = mbox_request_channel(cl, idx);
if (IS_ERR(cinfo->chan)) {
ret = PTR_ERR(cinfo->chan);
if (ret != -EPROBE_DEFER)
dev_err(dev, "failed to request SCMI %s mailbox\n",
desc);
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_mbox_txrx_setup(struct scmi_info *info, struct device *dev, int prot_id)
{
int ret = scmi_mbox_chan_setup(info, dev, prot_id, true);
if (!ret) /* Rx is optional, hence no error check */
scmi_mbox_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_mbox_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;
/* Only mailbox method supported, check for the presence of one */
if (scmi_mailbox_check(np, 0)) {
dev_err(dev, "no mailbox found in %pOF\n", np);
return -EINVAL;
}
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_mbox_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;
}
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);
idr = &info->rx_idr;
ret = idr_for_each(idr, scmi_mbox_free_channel, 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);
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 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 <sudeep.holla@arm.com>");
MODULE_DESCRIPTION("ARM SCMI protocol driver");
MODULE_LICENSE("GPL v2");
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