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driver.c
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driver.c
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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) 2018-2021 ARM Ltd.
*/
#include <linux/bitmap.h>
#include <linux/device.h>
#include <linux/export.h>
#include <linux/idr.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/hashtable.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/processor.h>
#include <linux/refcount.h>
#include <linux/slab.h>
#include "common.h"
#include "notify.h"
#define CREATE_TRACE_POINTS
#include <trace/events/scmi.h>
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 */
};
/* 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;
static DEFINE_IDR(scmi_requested_devices);
static DEFINE_MUTEX(scmi_requested_devices_mtx);
struct scmi_requested_dev {
const struct scmi_device_id *id_table;
struct list_head node;
};
/**
* struct scmi_xfers_info - Structure to manage transfer information
*
* @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
* @max_msg: Maximum number of messages that can be pending
* @free_xfers: A free list for available to use xfers. It is initialized with
* a number of xfers equal to the maximum allowed in-flight
* messages.
* @pending_xfers: An hashtable, indexed by msg_hdr.seq, used to keep all the
* currently in-flight messages.
*/
struct scmi_xfers_info {
unsigned long *xfer_alloc_table;
spinlock_t xfer_lock;
int max_msg;
struct hlist_head free_xfers;
DECLARE_HASHTABLE(pending_xfers, SCMI_PENDING_XFERS_HT_ORDER_SZ);
};
/**
* struct scmi_protocol_instance - Describe an initialized protocol instance.
* @handle: Reference to the SCMI handle associated to this protocol instance.
* @proto: A reference to the protocol descriptor.
* @gid: A reference for per-protocol devres management.
* @users: A refcount to track effective users of this protocol.
* @priv: Reference for optional protocol private data.
* @ph: An embedded protocol handle that will be passed down to protocol
* initialization code to identify this instance.
*
* Each protocol is initialized independently once for each SCMI platform in
* which is defined by DT and implemented by the SCMI server fw.
*/
struct scmi_protocol_instance {
const struct scmi_handle *handle;
const struct scmi_protocol *proto;
void *gid;
refcount_t users;
void *priv;
struct scmi_protocol_handle ph;
};
#define ph_to_pi(h) container_of(h, struct scmi_protocol_instance, ph)
/**
* 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
* @rx_minfo: Universal Receive 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: IDR for protocols' instance descriptors initialized for
* this SCMI instance: populated on protocol's first attempted
* usage.
* @protocols_mtx: A mutex to protect protocols instances initialization.
* @protocols_imp: List of protocols implemented, currently maximum of
* MAX_PROTOCOLS_IMP elements allocated by the base protocol
* @active_protocols: IDR storing device_nodes for protocols actually defined
* in the DT and confirmed as implemented by fw.
* @notify_priv: Pointer to private data structure specific to notifications.
* @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 scmi_xfers_info rx_minfo;
struct idr tx_idr;
struct idr rx_idr;
struct idr protocols;
/* Ensure mutual exclusive access to protocols instance array */
struct mutex protocols_mtx;
u8 *protocols_imp;
struct idr active_protocols;
void *notify_priv;
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)
{
int err_idx = -errno;
if (err_idx >= SCMI_SUCCESS && err_idx < ARRAY_SIZE(scmi_linux_errmap))
return scmi_linux_errmap[err_idx];
return -EIO;
}
void scmi_notification_instance_data_set(const struct scmi_handle *handle,
void *priv)
{
struct scmi_info *info = handle_to_scmi_info(handle);
info->notify_priv = priv;
/* Ensure updated protocol private date are visible */
smp_wmb();
}
void *scmi_notification_instance_data_get(const struct scmi_handle *handle)
{
struct scmi_info *info = handle_to_scmi_info(handle);
/* Ensure protocols_private_data has been updated */
smp_rmb();
return info->notify_priv;
}
/**
* scmi_xfer_token_set - Reserve and set new token for the xfer at hand
*
* @minfo: Pointer to Tx/Rx Message management info based on channel type
* @xfer: The xfer to act upon
*
* Pick the next unused monotonically increasing token and set it into
* xfer->hdr.seq: picking a monotonically increasing value avoids immediate
* reuse of freshly completed or timed-out xfers, thus mitigating the risk
* of incorrect association of a late and expired xfer with a live in-flight
* transaction, both happening to re-use the same token identifier.
*
* Since platform is NOT required to answer our request in-order we should
* account for a few rare but possible scenarios:
*
* - exactly 'next_token' may be NOT available so pick xfer_id >= next_token
* using find_next_zero_bit() starting from candidate next_token bit
*
* - all tokens ahead upto (MSG_TOKEN_ID_MASK - 1) are used in-flight but we
* are plenty of free tokens at start, so try a second pass using
* find_next_zero_bit() and starting from 0.
*
* X = used in-flight
*
* Normal
* ------
*
* |- xfer_id picked
* -----------+----------------------------------------------------------
* | | |X|X|X| | | | | | ... ... ... ... ... ... ... ... ... ... ...|X|X|
* ----------------------------------------------------------------------
* ^
* |- next_token
*
* Out-of-order pending at start
* -----------------------------
*
* |- xfer_id picked, last_token fixed
* -----+----------------------------------------------------------------
* |X|X| | | | |X|X| ... ... ... ... ... ... ... ... ... ... ... ...|X| |
* ----------------------------------------------------------------------
* ^
* |- next_token
*
*
* Out-of-order pending at end
* ---------------------------
*
* |- xfer_id picked, last_token fixed
* -----+----------------------------------------------------------------
* |X|X| | | | |X|X| ... ... ... ... ... ... ... ... ... ... |X|X|X||X|X|
* ----------------------------------------------------------------------
* ^
* |- next_token
*
* Context: Assumes to be called with @xfer_lock already acquired.
*
* Return: 0 on Success or error
*/
static int scmi_xfer_token_set(struct scmi_xfers_info *minfo,
struct scmi_xfer *xfer)
{
unsigned long xfer_id, next_token;
/*
* Pick a candidate monotonic token in range [0, MSG_TOKEN_MAX - 1]
* using the pre-allocated transfer_id as a base.
* Note that the global transfer_id is shared across all message types
* so there could be holes in the allocated set of monotonic sequence
* numbers, but that is going to limit the effectiveness of the
* mitigation only in very rare limit conditions.
*/
next_token = (xfer->transfer_id & (MSG_TOKEN_MAX - 1));
/* Pick the next available xfer_id >= next_token */
xfer_id = find_next_zero_bit(minfo->xfer_alloc_table,
MSG_TOKEN_MAX, next_token);
if (xfer_id == MSG_TOKEN_MAX) {
/*
* After heavily out-of-order responses, there are no free
* tokens ahead, but only at start of xfer_alloc_table so
* try again from the beginning.
*/
xfer_id = find_next_zero_bit(minfo->xfer_alloc_table,
MSG_TOKEN_MAX, 0);
/*
* Something is wrong if we got here since there can be a
* maximum number of (MSG_TOKEN_MAX - 1) in-flight messages
* but we have not found any free token [0, MSG_TOKEN_MAX - 1].
*/
if (WARN_ON_ONCE(xfer_id == MSG_TOKEN_MAX))
return -ENOMEM;
}
/* Update +/- last_token accordingly if we skipped some hole */
if (xfer_id != next_token)
atomic_add((int)(xfer_id - next_token), &transfer_last_id);
/* Set in-flight */
set_bit(xfer_id, minfo->xfer_alloc_table);
xfer->hdr.seq = (u16)xfer_id;
return 0;
}
/**
* scmi_xfer_token_clear - Release the token
*
* @minfo: Pointer to Tx/Rx Message management info based on channel type
* @xfer: The xfer to act upon
*/
static inline void scmi_xfer_token_clear(struct scmi_xfers_info *minfo,
struct scmi_xfer *xfer)
{
clear_bit(xfer->hdr.seq, minfo->xfer_alloc_table);
}
/**
* scmi_xfer_get() - Allocate one message
*
* @handle: Pointer to SCMI entity handle
* @minfo: Pointer to Tx/Rx Message management info based on channel type
* @set_pending: If true a monotonic token is picked and the xfer is added to
* the pending hash table.
*
* Helper function which is used by various message functions that are
* exposed to clients of this driver for allocating a message traffic event.
*
* Picks an xfer from the free list @free_xfers (if any available) and, if
* required, sets a monotonically increasing token and stores the inflight xfer
* into the @pending_xfers hashtable for later retrieval.
*
* The successfully initialized xfer is refcounted.
*
* Context: Holds @xfer_lock while manipulating @xfer_alloc_table and
* @free_xfers.
*
* 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,
bool set_pending)
{
int ret;
unsigned long flags;
struct scmi_xfer *xfer;
spin_lock_irqsave(&minfo->xfer_lock, flags);
if (hlist_empty(&minfo->free_xfers)) {
spin_unlock_irqrestore(&minfo->xfer_lock, flags);
return ERR_PTR(-ENOMEM);
}
/* grab an xfer from the free_list */
xfer = hlist_entry(minfo->free_xfers.first, struct scmi_xfer, node);
hlist_del_init(&xfer->node);
/*
* Allocate transfer_id early so that can be used also as base for
* monotonic sequence number generation if needed.
*/
xfer->transfer_id = atomic_inc_return(&transfer_last_id);
if (set_pending) {
/* Pick and set monotonic token */
ret = scmi_xfer_token_set(minfo, xfer);
if (!ret) {
hash_add(minfo->pending_xfers, &xfer->node,
xfer->hdr.seq);
xfer->pending = true;
} else {
dev_err(handle->dev,
"Failed to get monotonic token %d\n", ret);
hlist_add_head(&xfer->node, &minfo->free_xfers);
xfer = ERR_PTR(ret);
}
}
if (!IS_ERR(xfer)) {
refcount_set(&xfer->users, 1);
atomic_set(&xfer->busy, SCMI_XFER_FREE);
}
spin_unlock_irqrestore(&minfo->xfer_lock, flags);
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
*
* After refcount check, possibly release an xfer, clearing the token slot,
* removing xfer from @pending_xfers and putting it back into free_xfers.
*
* 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;
spin_lock_irqsave(&minfo->xfer_lock, flags);
if (refcount_dec_and_test(&xfer->users)) {
if (xfer->pending) {
scmi_xfer_token_clear(minfo, xfer);
hash_del(&xfer->node);
xfer->pending = false;
}
hlist_add_head(&xfer->node, &minfo->free_xfers);
}
spin_unlock_irqrestore(&minfo->xfer_lock, flags);
}
/**
* scmi_xfer_lookup_unlocked - Helper to lookup an xfer_id
*
* @minfo: Pointer to Tx/Rx Message management info based on channel type
* @xfer_id: Token ID to lookup in @pending_xfers
*
* Refcounting is untouched.
*
* Context: Assumes to be called with @xfer_lock already acquired.
*
* Return: A valid xfer on Success or error otherwise
*/
static struct scmi_xfer *
scmi_xfer_lookup_unlocked(struct scmi_xfers_info *minfo, u16 xfer_id)
{
struct scmi_xfer *xfer = NULL;
if (test_bit(xfer_id, minfo->xfer_alloc_table))
xfer = XFER_FIND(minfo->pending_xfers, xfer_id);
return xfer ?: ERR_PTR(-EINVAL);
}
/**
* scmi_msg_response_validate - Validate message type against state of related
* xfer
*
* @cinfo: A reference to the channel descriptor.
* @msg_type: Message type to check
* @xfer: A reference to the xfer to validate against @msg_type
*
* This function checks if @msg_type is congruent with the current state of
* a pending @xfer; if an asynchronous delayed response is received before the
* related synchronous response (Out-of-Order Delayed Response) the missing
* synchronous response is assumed to be OK and completed, carrying on with the
* Delayed Response: this is done to address the case in which the underlying
* SCMI transport can deliver such out-of-order responses.
*
* Context: Assumes to be called with xfer->lock already acquired.
*
* Return: 0 on Success, error otherwise
*/
static inline int scmi_msg_response_validate(struct scmi_chan_info *cinfo,
u8 msg_type,
struct scmi_xfer *xfer)
{
/*
* Even if a response was indeed expected on this slot at this point,
* a buggy platform could wrongly reply feeding us an unexpected
* delayed response we're not prepared to handle: bail-out safely
* blaming firmware.
*/
if (msg_type == MSG_TYPE_DELAYED_RESP && !xfer->async_done) {
dev_err(cinfo->dev,
"Delayed Response for %d not expected! Buggy F/W ?\n",
xfer->hdr.seq);
return -EINVAL;
}
switch (xfer->state) {
case SCMI_XFER_SENT_OK:
if (msg_type == MSG_TYPE_DELAYED_RESP) {
/*
* Delayed Response expected but delivered earlier.
* Assume message RESPONSE was OK and skip state.
*/
xfer->hdr.status = SCMI_SUCCESS;
xfer->state = SCMI_XFER_RESP_OK;
complete(&xfer->done);
dev_warn(cinfo->dev,
"Received valid OoO Delayed Response for %d\n",
xfer->hdr.seq);
}
break;
case SCMI_XFER_RESP_OK:
if (msg_type != MSG_TYPE_DELAYED_RESP)
return -EINVAL;
break;
case SCMI_XFER_DRESP_OK:
/* No further message expected once in SCMI_XFER_DRESP_OK */
return -EINVAL;
}
return 0;
}
/**
* scmi_xfer_state_update - Update xfer state
*
* @xfer: A reference to the xfer to update
* @msg_type: Type of message being processed.
*
* Note that this message is assumed to have been already successfully validated
* by @scmi_msg_response_validate(), so here we just update the state.
*
* Context: Assumes to be called on an xfer exclusively acquired using the
* busy flag.
*/
static inline void scmi_xfer_state_update(struct scmi_xfer *xfer, u8 msg_type)
{
xfer->hdr.type = msg_type;
/* Unknown command types were already discarded earlier */
if (xfer->hdr.type == MSG_TYPE_COMMAND)
xfer->state = SCMI_XFER_RESP_OK;
else
xfer->state = SCMI_XFER_DRESP_OK;
}
static bool scmi_xfer_acquired(struct scmi_xfer *xfer)
{
int ret;
ret = atomic_cmpxchg(&xfer->busy, SCMI_XFER_FREE, SCMI_XFER_BUSY);
return ret == SCMI_XFER_FREE;
}
/**
* scmi_xfer_command_acquire - Helper to lookup and acquire a command xfer
*
* @cinfo: A reference to the channel descriptor.
* @msg_hdr: A message header to use as lookup key
*
* When a valid xfer is found for the sequence number embedded in the provided
* msg_hdr, reference counting is properly updated and exclusive access to this
* xfer is granted till released with @scmi_xfer_command_release.
*
* Return: A valid @xfer on Success or error otherwise.
*/
static inline struct scmi_xfer *
scmi_xfer_command_acquire(struct scmi_chan_info *cinfo, u32 msg_hdr)
{
int ret;
unsigned long flags;
struct scmi_xfer *xfer;
struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
struct scmi_xfers_info *minfo = &info->tx_minfo;
u8 msg_type = MSG_XTRACT_TYPE(msg_hdr);
u16 xfer_id = MSG_XTRACT_TOKEN(msg_hdr);
/* Are we even expecting this? */
spin_lock_irqsave(&minfo->xfer_lock, flags);
xfer = scmi_xfer_lookup_unlocked(minfo, xfer_id);
if (IS_ERR(xfer)) {
dev_err(cinfo->dev,
"Message for %d type %d is not expected!\n",
xfer_id, msg_type);
spin_unlock_irqrestore(&minfo->xfer_lock, flags);
return xfer;
}
refcount_inc(&xfer->users);
spin_unlock_irqrestore(&minfo->xfer_lock, flags);
spin_lock_irqsave(&xfer->lock, flags);
ret = scmi_msg_response_validate(cinfo, msg_type, xfer);
/*
* If a pending xfer was found which was also in a congruent state with
* the received message, acquire exclusive access to it setting the busy
* flag.
* Spins only on the rare limit condition of concurrent reception of
* RESP and DRESP for the same xfer.
*/
if (!ret) {
spin_until_cond(scmi_xfer_acquired(xfer));
scmi_xfer_state_update(xfer, msg_type);
}
spin_unlock_irqrestore(&xfer->lock, flags);
if (ret) {
dev_err(cinfo->dev,
"Invalid message type:%d for %d - HDR:0x%X state:%d\n",
msg_type, xfer_id, msg_hdr, xfer->state);
/* On error the refcount incremented above has to be dropped */
__scmi_xfer_put(minfo, xfer);
xfer = ERR_PTR(-EINVAL);
}
return xfer;
}
static inline void scmi_xfer_command_release(struct scmi_info *info,
struct scmi_xfer *xfer)
{
atomic_set(&xfer->busy, SCMI_XFER_FREE);
__scmi_xfer_put(&info->tx_minfo, xfer);
}
static inline void scmi_clear_channel(struct scmi_info *info,
struct scmi_chan_info *cinfo)
{
if (info->desc->ops->clear_channel)
info->desc->ops->clear_channel(cinfo);
}
static void scmi_handle_notification(struct scmi_chan_info *cinfo,
u32 msg_hdr, void *priv)
{
struct scmi_xfer *xfer;
struct device *dev = cinfo->dev;
struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
struct scmi_xfers_info *minfo = &info->rx_minfo;
ktime_t ts;
ts = ktime_get_boottime();
xfer = scmi_xfer_get(cinfo->handle, minfo, false);
if (IS_ERR(xfer)) {
dev_err(dev, "failed to get free message slot (%ld)\n",
PTR_ERR(xfer));
scmi_clear_channel(info, cinfo);
return;
}
unpack_scmi_header(msg_hdr, &xfer->hdr);
if (priv)
xfer->priv = priv;
info->desc->ops->fetch_notification(cinfo, info->desc->max_msg_size,
xfer);
scmi_notify(cinfo->handle, xfer->hdr.protocol_id,
xfer->hdr.id, xfer->rx.buf, xfer->rx.len, ts);
trace_scmi_rx_done(xfer->transfer_id, xfer->hdr.id,
xfer->hdr.protocol_id, xfer->hdr.seq,
MSG_TYPE_NOTIFICATION);
__scmi_xfer_put(minfo, xfer);
scmi_clear_channel(info, cinfo);
}
static void scmi_handle_response(struct scmi_chan_info *cinfo,
u32 msg_hdr, void *priv)
{
struct scmi_xfer *xfer;
struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
xfer = scmi_xfer_command_acquire(cinfo, msg_hdr);
if (IS_ERR(xfer)) {
scmi_clear_channel(info, cinfo);
return;
}
/* rx.len could be shrunk in the sync do_xfer, so reset to maxsz */
if (xfer->hdr.type == MSG_TYPE_DELAYED_RESP)
xfer->rx.len = info->desc->max_msg_size;
if (priv)
xfer->priv = priv;
info->desc->ops->fetch_response(cinfo, xfer);
trace_scmi_rx_done(xfer->transfer_id, xfer->hdr.id,
xfer->hdr.protocol_id, xfer->hdr.seq,
xfer->hdr.type);
if (xfer->hdr.type == MSG_TYPE_DELAYED_RESP) {
scmi_clear_channel(info, cinfo);
complete(xfer->async_done);
} else {
complete(&xfer->done);
}
scmi_xfer_command_release(info, xfer);
}
/**
* scmi_rx_callback() - callback for receiving messages
*
* @cinfo: SCMI channel info
* @msg_hdr: Message header
* @priv: Transport specific private data.
*
* 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, void *priv)
{
u8 msg_type = MSG_XTRACT_TYPE(msg_hdr);
switch (msg_type) {
case MSG_TYPE_NOTIFICATION:
scmi_handle_notification(cinfo, msg_hdr, priv);
break;
case MSG_TYPE_COMMAND:
case MSG_TYPE_DELAYED_RESP:
scmi_handle_response(cinfo, msg_hdr, priv);
break;
default:
WARN_ONCE(1, "received unknown msg_type:%d\n", msg_type);
break;
}
}
/**
* xfer_put() - Release a transmit message
*
* @ph: Pointer to SCMI protocol handle
* @xfer: message that was reserved by xfer_get_init
*/
static void xfer_put(const struct scmi_protocol_handle *ph,
struct scmi_xfer *xfer)
{
const struct scmi_protocol_instance *pi = ph_to_pi(ph);
struct scmi_info *info = handle_to_scmi_info(pi->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);
/*
* Poll also on xfer->done so that polling can be forcibly terminated
* in case of out-of-order receptions of delayed responses
*/
return info->desc->ops->poll_done(cinfo, xfer) ||
try_wait_for_completion(&xfer->done) ||
ktime_after(ktime_get(), stop);
}
/**
* do_xfer() - Do one transfer
*
* @ph: Pointer to SCMI protocol 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.
*/
static int do_xfer(const struct scmi_protocol_handle *ph,
struct scmi_xfer *xfer)
{
int ret;
int timeout;
const struct scmi_protocol_instance *pi = ph_to_pi(ph);
struct scmi_info *info = handle_to_scmi_info(pi->handle);
struct device *dev = info->dev;
struct scmi_chan_info *cinfo;
if (xfer->hdr.poll_completion && !info->desc->ops->poll_done) {
dev_warn_once(dev,
"Polling mode is not supported by transport.\n");
return -EINVAL;
}
/*
* Initialise protocol id now from protocol handle to avoid it being
* overridden by mistake (or malice) by the protocol code mangling with
* the scmi_xfer structure prior to this.
*/
xfer->hdr.protocol_id = pi->proto->id;
reinit_completion(&xfer->done);
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);
xfer->state = SCMI_XFER_SENT_OK;
/*
* Even though spinlocking is not needed here since no race is possible
* on xfer->state due to the monotonically increasing tokens allocation,
* we must anyway ensure xfer->state initialization is not re-ordered
* after the .send_message() to be sure that on the RX path an early
* ISR calling scmi_rx_callback() cannot see an old stale xfer->state.
*/
smp_mb();
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)) {
unsigned long flags;
/*
* Do not fetch_response if an out-of-order delayed
* response is being processed.
*/
spin_lock_irqsave(&xfer->lock, flags);
if (xfer->state == SCMI_XFER_SENT_OK) {
info->desc->ops->fetch_response(cinfo, xfer);
xfer->state = SCMI_XFER_RESP_OK;
}
spin_unlock_irqrestore(&xfer->lock, flags);
} 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, ret);
return ret;
}
static void reset_rx_to_maxsz(const struct scmi_protocol_handle *ph,
struct scmi_xfer *xfer)
{
const struct scmi_protocol_instance *pi = ph_to_pi(ph);
struct scmi_info *info = handle_to_scmi_info(pi->handle);
xfer->rx.len = info->desc->max_msg_size;
}
#define SCMI_MAX_RESPONSE_TIMEOUT (2 * MSEC_PER_SEC)
/**
* do_xfer_with_response() - Do one transfer and wait until the delayed
* response is received
*
* @ph: Pointer to SCMI protocol 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.
*/
static int do_xfer_with_response(const struct scmi_protocol_handle *ph,
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 = do_xfer(ph, xfer);
if (!ret) {
if (!wait_for_completion_timeout(xfer->async_done, timeout))
ret = -ETIMEDOUT;
else if (xfer->hdr.status)
ret = scmi_to_linux_errno(xfer->hdr.status);
}
xfer->async_done = NULL;
return ret;
}
/**
* xfer_get_init() - Allocate and initialise one message for transmit
*
* @ph: Pointer to SCMI protocol handle
* @msg_id: Message identifier
* @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.
*/
static int xfer_get_init(const struct scmi_protocol_handle *ph,
u8 msg_id, size_t tx_size, size_t rx_size,
struct scmi_xfer **p)
{
int ret;
struct scmi_xfer *xfer;
const struct scmi_protocol_instance *pi = ph_to_pi(ph);
struct scmi_info *info = handle_to_scmi_info(pi->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(pi->handle, minfo, true);
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.type = MSG_TYPE_COMMAND;
xfer->hdr.id = msg_id;
xfer->hdr.poll_completion = false;
*p = xfer;
return 0;
}
/**
* version_get() - command to get the revision of the SCMI entity
*
* @ph: Pointer to SCMI protocol handle
* @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.
*/
static int version_get(const struct scmi_protocol_handle *ph, u32 *version)
{
int ret;
__le32 *rev_info;
struct scmi_xfer *t;
ret = xfer_get_init(ph, PROTOCOL_VERSION, 0, sizeof(*version), &t);
if (ret)
return ret;
ret = do_xfer(ph, t);
if (!ret) {
rev_info = t->rx.buf;
*version = le32_to_cpu(*rev_info);
}
xfer_put(ph, t);
return ret;
}
/**
* scmi_set_protocol_priv - Set protocol specific data at init time
*
* @ph: A reference to the protocol handle.
* @priv: The private data to set.
*
* Return: 0 on Success
*/
static int scmi_set_protocol_priv(const struct scmi_protocol_handle *ph,
void *priv)
{
struct scmi_protocol_instance *pi = ph_to_pi(ph);
pi->priv = priv;
return 0;
}
/**
* scmi_get_protocol_priv - Set protocol specific data at init time
*
* @ph: A reference to the protocol handle.
*
* Return: Protocol private data if any was set.
*/
static void *scmi_get_protocol_priv(const struct scmi_protocol_handle *ph)
{
const struct scmi_protocol_instance *pi = ph_to_pi(ph);
return pi->priv;
}
static const struct scmi_xfer_ops xfer_ops = {
.version_get = version_get,
.xfer_get_init = xfer_get_init,
.reset_rx_to_maxsz = reset_rx_to_maxsz,
.do_xfer = do_xfer,
.do_xfer_with_response = do_xfer_with_response,