linux-zen-server/drivers/firmware/arm_scmi/raw_mode.c

1444 lines
41 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* System Control and Management Interface (SCMI) Raw mode support
*
* Copyright (C) 2022 ARM Ltd.
*/
/**
* DOC: Theory of operation
*
* When enabled the SCMI Raw mode support exposes a userspace API which allows
* to send and receive SCMI commands, replies and notifications from a user
* application through injection and snooping of bare SCMI messages in binary
* little-endian format.
*
* Such injected SCMI transactions will then be routed through the SCMI core
* stack towards the SCMI backend server using whatever SCMI transport is
* currently configured on the system under test.
*
* It is meant to help in running any sort of SCMI backend server testing, no
* matter where the server is placed, as long as it is normally reachable via
* the transport configured on the system.
*
* It is activated by a Kernel configuration option since it is NOT meant to
* be used in production but only during development and in CI deployments.
*
* In order to avoid possible interferences between the SCMI Raw transactions
* originated from a test-suite and the normal operations of the SCMI drivers,
* when Raw mode is enabled, by default, all the regular SCMI drivers are
* inhibited, unless CONFIG_ARM_SCMI_RAW_MODE_SUPPORT_COEX is enabled: in this
* latter case the regular SCMI stack drivers will be loaded as usual and it is
* up to the user of this interface to take care of manually inhibiting the
* regular SCMI drivers in order to avoid interferences during the test runs.
*
* The exposed API is as follows.
*
* All SCMI Raw entries are rooted under a common top /raw debugfs top directory
* which in turn is rooted under the corresponding underlying SCMI instance.
*
* /sys/kernel/debug/scmi/
* `-- 0
* |-- atomic_threshold_us
* |-- instance_name
* |-- raw
* | |-- channels
* | | |-- 0x10
* | | | |-- message
* | | | `-- message_async
* | | `-- 0x13
* | | |-- message
* | | `-- message_async
* | |-- errors
* | |-- message
* | |-- message_async
* | |-- notification
* | `-- reset
* `-- transport
* |-- is_atomic
* |-- max_msg_size
* |-- max_rx_timeout_ms
* |-- rx_max_msg
* |-- tx_max_msg
* `-- type
*
* where:
*
* - errors: used to read back timed-out and unexpected replies
* - message*: used to send sync/async commands and read back immediate and
* delayed reponses (if any)
* - notification: used to read any notification being emitted by the system
* (if previously enabled by the user app)
* - reset: used to flush the queues of messages (of any kind) still pending
* to be read; this is useful at test-suite start/stop to get
* rid of any unread messages from the previous run.
*
* with the per-channel entries rooted at /channels being present only on a
* system where multiple transport channels have been configured.
*
* Such per-channel entries can be used to explicitly choose a specific channel
* for SCMI bare message injection, in contrast with the general entries above
* where, instead, the selection of the proper channel to use is automatically
* performed based the protocol embedded in the injected message and on how the
* transport is configured on the system.
*
* Note that other common general entries are available under transport/ to let
* the user applications properly make up their expectations in terms of
* timeouts and message characteristics.
*
* Each write to the message* entries causes one command request to be built
* and sent while the replies or delayed response are read back from those same
* entries one message at time (receiving an EOF at each message boundary).
*
* The user application running the test is in charge of handling timeouts
* on replies and properly choosing SCMI sequence numbers for the outgoing
* requests (using the same sequence number is supported but discouraged).
*
* Injection of multiple in-flight requests is supported as long as the user
* application uses properly distinct sequence numbers for concurrent requests
* and takes care to properly manage all the related issues about concurrency
* and command/reply pairing. Keep in mind that, anyway, the real level of
* parallelism attainable in such scenario is dependent on the characteristics
* of the underlying transport being used.
*
* Since the SCMI core regular stack is partially used to deliver and collect
* the messages, late replies arrived after timeouts and any other sort of
* unexpected message can be identified by the SCMI core as usual and they will
* be reported as messages under "errors" for later analysis.
*/
#include <linux/bitmap.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/export.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/xarray.h>
#include "common.h"
#include "raw_mode.h"
#include <trace/events/scmi.h>
#define SCMI_XFER_RAW_MAX_RETRIES 10
/**
* struct scmi_raw_queue - Generic Raw queue descriptor
*
* @free_bufs: A freelists listhead used to keep unused raw buffers
* @free_bufs_lock: Spinlock used to protect access to @free_bufs
* @msg_q: A listhead to a queue of snooped messages waiting to be read out
* @msg_q_lock: Spinlock used to protect access to @msg_q
* @wq: A waitqueue used to wait and poll on related @msg_q
*/
struct scmi_raw_queue {
struct list_head free_bufs;
/* Protect free_bufs[] lists */
spinlock_t free_bufs_lock;
struct list_head msg_q;
/* Protect msg_q[] lists */
spinlock_t msg_q_lock;
wait_queue_head_t wq;
};
/**
* struct scmi_raw_mode_info - Structure holding SCMI Raw instance data
*
* @id: Sequential Raw instance ID.
* @handle: Pointer to SCMI entity handle to use
* @desc: Pointer to the transport descriptor to use
* @tx_max_msg: Maximum number of concurrent TX in-flight messages
* @q: An array of Raw queue descriptors
* @chans_q: An XArray mapping optional additional per-channel queues
* @free_waiters: Head of freelist for unused waiters
* @free_mtx: A mutex to protect the waiters freelist
* @active_waiters: Head of list for currently active and used waiters
* @active_mtx: A mutex to protect the active waiters list
* @waiters_work: A work descriptor to be used with the workqueue machinery
* @wait_wq: A workqueue reference to the created workqueue
* @dentry: Top debugfs root dentry for SCMI Raw
* @gid: A group ID used for devres accounting
*
* Note that this descriptor is passed back to the core after SCMI Raw is
* initialized as an opaque handle to use by subsequent SCMI Raw call hooks.
*
*/
struct scmi_raw_mode_info {
unsigned int id;
const struct scmi_handle *handle;
const struct scmi_desc *desc;
int tx_max_msg;
struct scmi_raw_queue *q[SCMI_RAW_MAX_QUEUE];
struct xarray chans_q;
struct list_head free_waiters;
/* Protect free_waiters list */
struct mutex free_mtx;
struct list_head active_waiters;
/* Protect active_waiters list */
struct mutex active_mtx;
struct work_struct waiters_work;
struct workqueue_struct *wait_wq;
struct dentry *dentry;
void *gid;
};
/**
* struct scmi_xfer_raw_waiter - Structure to describe an xfer to be waited for
*
* @start_jiffies: The timestamp in jiffies of when this structure was queued.
* @cinfo: A reference to the channel to use for this transaction
* @xfer: A reference to the xfer to be waited for
* @async_response: A completion to be, optionally, used for async waits: it
* will be setup by @scmi_do_xfer_raw_start, if needed, to be
* pointed at by xfer->async_done.
* @node: A list node.
*/
struct scmi_xfer_raw_waiter {
unsigned long start_jiffies;
struct scmi_chan_info *cinfo;
struct scmi_xfer *xfer;
struct completion async_response;
struct list_head node;
};
/**
* struct scmi_raw_buffer - Structure to hold a full SCMI message
*
* @max_len: The maximum allowed message size (header included) that can be
* stored into @msg
* @msg: A message buffer used to collect a full message grabbed from an xfer.
* @node: A list node.
*/
struct scmi_raw_buffer {
size_t max_len;
struct scmi_msg msg;
struct list_head node;
};
/**
* struct scmi_dbg_raw_data - Structure holding data needed by the debugfs
* layer
*
* @chan_id: The preferred channel to use: if zero the channel is automatically
* selected based on protocol.
* @raw: A reference to the Raw instance.
* @tx: A message buffer used to collect TX message on write.
* @tx_size: The effective size of the TX message.
* @tx_req_size: The final expected size of the complete TX message.
* @rx: A message buffer to collect RX message on read.
* @rx_size: The effective size of the RX message.
*/
struct scmi_dbg_raw_data {
u8 chan_id;
struct scmi_raw_mode_info *raw;
struct scmi_msg tx;
size_t tx_size;
size_t tx_req_size;
struct scmi_msg rx;
size_t rx_size;
};
static struct scmi_raw_queue *
scmi_raw_queue_select(struct scmi_raw_mode_info *raw, unsigned int idx,
unsigned int chan_id)
{
if (!chan_id)
return raw->q[idx];
return xa_load(&raw->chans_q, chan_id);
}
static struct scmi_raw_buffer *scmi_raw_buffer_get(struct scmi_raw_queue *q)
{
unsigned long flags;
struct scmi_raw_buffer *rb = NULL;
struct list_head *head = &q->free_bufs;
spin_lock_irqsave(&q->free_bufs_lock, flags);
if (!list_empty(head)) {
rb = list_first_entry(head, struct scmi_raw_buffer, node);
list_del_init(&rb->node);
}
spin_unlock_irqrestore(&q->free_bufs_lock, flags);
return rb;
}
static void scmi_raw_buffer_put(struct scmi_raw_queue *q,
struct scmi_raw_buffer *rb)
{
unsigned long flags;
/* Reset to full buffer length */
rb->msg.len = rb->max_len;
spin_lock_irqsave(&q->free_bufs_lock, flags);
list_add_tail(&rb->node, &q->free_bufs);
spin_unlock_irqrestore(&q->free_bufs_lock, flags);
}
static void scmi_raw_buffer_enqueue(struct scmi_raw_queue *q,
struct scmi_raw_buffer *rb)
{
unsigned long flags;
spin_lock_irqsave(&q->msg_q_lock, flags);
list_add_tail(&rb->node, &q->msg_q);
spin_unlock_irqrestore(&q->msg_q_lock, flags);
wake_up_interruptible(&q->wq);
}
static struct scmi_raw_buffer*
scmi_raw_buffer_dequeue_unlocked(struct scmi_raw_queue *q)
{
struct scmi_raw_buffer *rb = NULL;
if (!list_empty(&q->msg_q)) {
rb = list_first_entry(&q->msg_q, struct scmi_raw_buffer, node);
list_del_init(&rb->node);
}
return rb;
}
static struct scmi_raw_buffer *scmi_raw_buffer_dequeue(struct scmi_raw_queue *q)
{
unsigned long flags;
struct scmi_raw_buffer *rb;
spin_lock_irqsave(&q->msg_q_lock, flags);
rb = scmi_raw_buffer_dequeue_unlocked(q);
spin_unlock_irqrestore(&q->msg_q_lock, flags);
return rb;
}
static void scmi_raw_buffer_queue_flush(struct scmi_raw_queue *q)
{
struct scmi_raw_buffer *rb;
do {
rb = scmi_raw_buffer_dequeue(q);
if (rb)
scmi_raw_buffer_put(q, rb);
} while (rb);
}
static struct scmi_xfer_raw_waiter *
scmi_xfer_raw_waiter_get(struct scmi_raw_mode_info *raw, struct scmi_xfer *xfer,
struct scmi_chan_info *cinfo, bool async)
{
struct scmi_xfer_raw_waiter *rw = NULL;
mutex_lock(&raw->free_mtx);
if (!list_empty(&raw->free_waiters)) {
rw = list_first_entry(&raw->free_waiters,
struct scmi_xfer_raw_waiter, node);
list_del_init(&rw->node);
if (async) {
reinit_completion(&rw->async_response);
xfer->async_done = &rw->async_response;
}
rw->cinfo = cinfo;
rw->xfer = xfer;
}
mutex_unlock(&raw->free_mtx);
return rw;
}
static void scmi_xfer_raw_waiter_put(struct scmi_raw_mode_info *raw,
struct scmi_xfer_raw_waiter *rw)
{
if (rw->xfer) {
rw->xfer->async_done = NULL;
rw->xfer = NULL;
}
mutex_lock(&raw->free_mtx);
list_add_tail(&rw->node, &raw->free_waiters);
mutex_unlock(&raw->free_mtx);
}
static void scmi_xfer_raw_waiter_enqueue(struct scmi_raw_mode_info *raw,
struct scmi_xfer_raw_waiter *rw)
{
/* A timestamp for the deferred worker to know how much this has aged */
rw->start_jiffies = jiffies;
trace_scmi_xfer_response_wait(rw->xfer->transfer_id, rw->xfer->hdr.id,
rw->xfer->hdr.protocol_id,
rw->xfer->hdr.seq,
raw->desc->max_rx_timeout_ms,
rw->xfer->hdr.poll_completion);
mutex_lock(&raw->active_mtx);
list_add_tail(&rw->node, &raw->active_waiters);
mutex_unlock(&raw->active_mtx);
/* kick waiter work */
queue_work(raw->wait_wq, &raw->waiters_work);
}
static struct scmi_xfer_raw_waiter *
scmi_xfer_raw_waiter_dequeue(struct scmi_raw_mode_info *raw)
{
struct scmi_xfer_raw_waiter *rw = NULL;
mutex_lock(&raw->active_mtx);
if (!list_empty(&raw->active_waiters)) {
rw = list_first_entry(&raw->active_waiters,
struct scmi_xfer_raw_waiter, node);
list_del_init(&rw->node);
}
mutex_unlock(&raw->active_mtx);
return rw;
}
/**
* scmi_xfer_raw_worker - Work function to wait for Raw xfers completions
*
* @work: A reference to the work.
*
* In SCMI Raw mode, once a user-provided injected SCMI message is sent, we
* cannot wait to receive its response (if any) in the context of the injection
* routines so as not to leave the userspace write syscall, which delivered the
* SCMI message to send, pending till eventually a reply is received.
* Userspace should and will poll/wait instead on the read syscalls which will
* be in charge of reading a received reply (if any).
*
* Even though reply messages are collected and reported into the SCMI Raw layer
* on the RX path, nonetheless we have to properly wait for their completion as
* usual (and async_completion too if needed) in order to properly release the
* xfer structure at the end: to do this out of the context of the write/send
* these waiting jobs are delegated to this deferred worker.
*
* Any sent xfer, to be waited for, is timestamped and queued for later
* consumption by this worker: queue aging is accounted for while choosing a
* timeout for the completion, BUT we do not really care here if we end up
* accidentally waiting for a bit too long.
*/
static void scmi_xfer_raw_worker(struct work_struct *work)
{
struct scmi_raw_mode_info *raw;
struct device *dev;
unsigned long max_tmo;
raw = container_of(work, struct scmi_raw_mode_info, waiters_work);
dev = raw->handle->dev;
max_tmo = msecs_to_jiffies(raw->desc->max_rx_timeout_ms);
do {
int ret = 0;
unsigned int timeout_ms;
unsigned long aging;
struct scmi_xfer *xfer;
struct scmi_xfer_raw_waiter *rw;
struct scmi_chan_info *cinfo;
rw = scmi_xfer_raw_waiter_dequeue(raw);
if (!rw)
return;
cinfo = rw->cinfo;
xfer = rw->xfer;
/*
* Waiters are queued by wait-deadline at the end, so some of
* them could have been already expired when processed, BUT we
* have to check the completion status anyway just in case a
* virtually expired (aged) transaction was indeed completed
* fine and we'll have to wait for the asynchronous part (if
* any): for this reason a 1 ms timeout is used for already
* expired/aged xfers.
*/
aging = jiffies - rw->start_jiffies;
timeout_ms = max_tmo > aging ?
jiffies_to_msecs(max_tmo - aging) : 1;
ret = scmi_xfer_raw_wait_for_message_response(cinfo, xfer,
timeout_ms);
if (!ret && xfer->hdr.status)
ret = scmi_to_linux_errno(xfer->hdr.status);
if (raw->desc->ops->mark_txdone)
raw->desc->ops->mark_txdone(rw->cinfo, ret, xfer);
trace_scmi_xfer_end(xfer->transfer_id, xfer->hdr.id,
xfer->hdr.protocol_id, xfer->hdr.seq, ret);
/* Wait also for an async delayed response if needed */
if (!ret && xfer->async_done) {
unsigned long tmo = msecs_to_jiffies(SCMI_MAX_RESPONSE_TIMEOUT);
if (!wait_for_completion_timeout(xfer->async_done, tmo))
dev_err(dev,
"timed out in RAW delayed resp - HDR:%08X\n",
pack_scmi_header(&xfer->hdr));
}
/* Release waiter and xfer */
scmi_xfer_raw_put(raw->handle, xfer);
scmi_xfer_raw_waiter_put(raw, rw);
} while (1);
}
static void scmi_xfer_raw_reset(struct scmi_raw_mode_info *raw)
{
int i;
dev_info(raw->handle->dev, "Resetting SCMI Raw stack.\n");
for (i = 0; i < SCMI_RAW_MAX_QUEUE; i++)
scmi_raw_buffer_queue_flush(raw->q[i]);
}
/**
* scmi_xfer_raw_get_init - An helper to build a valid xfer from the provided
* bare SCMI message.
*
* @raw: A reference to the Raw instance.
* @buf: A buffer containing the whole SCMI message to send (including the
* header) in little-endian binary formmat.
* @len: Length of the message in @buf.
* @p: A pointer to return the initialized Raw xfer.
*
* After an xfer is picked from the TX pool and filled in with the message
* content, the xfer is registered as pending with the core in the usual way
* using the original sequence number provided by the user with the message.
*
* Note that, in case the testing user application is NOT using distinct
* sequence-numbers between successive SCMI messages such registration could
* fail temporarily if the previous message, using the same sequence number,
* had still not released; in such a case we just wait and retry.
*
* Return: 0 on Success
*/
static int scmi_xfer_raw_get_init(struct scmi_raw_mode_info *raw, void *buf,
size_t len, struct scmi_xfer **p)
{
u32 msg_hdr;
size_t tx_size;
struct scmi_xfer *xfer;
int ret, retry = SCMI_XFER_RAW_MAX_RETRIES;
struct device *dev = raw->handle->dev;
if (!buf || len < sizeof(u32))
return -EINVAL;
tx_size = len - sizeof(u32);
/* Ensure we have sane transfer sizes */
if (tx_size > raw->desc->max_msg_size)
return -ERANGE;
xfer = scmi_xfer_raw_get(raw->handle);
if (IS_ERR(xfer)) {
dev_warn(dev, "RAW - Cannot get a free RAW xfer !\n");
return PTR_ERR(xfer);
}
/* Build xfer from the provided SCMI bare LE message */
msg_hdr = le32_to_cpu(*((__le32 *)buf));
unpack_scmi_header(msg_hdr, &xfer->hdr);
xfer->hdr.seq = (u16)MSG_XTRACT_TOKEN(msg_hdr);
/* Polling not supported */
xfer->hdr.poll_completion = false;
xfer->hdr.status = SCMI_SUCCESS;
xfer->tx.len = tx_size;
xfer->rx.len = raw->desc->max_msg_size;
/* Clear the whole TX buffer */
memset(xfer->tx.buf, 0x00, raw->desc->max_msg_size);
if (xfer->tx.len)
memcpy(xfer->tx.buf, (u8 *)buf + sizeof(msg_hdr), xfer->tx.len);
*p = xfer;
/*
* In flight registration can temporarily fail in case of Raw messages
* if the user injects messages without using monotonically increasing
* sequence numbers since, in Raw mode, the xfer (and the token) is
* finally released later by a deferred worker. Just retry for a while.
*/
do {
ret = scmi_xfer_raw_inflight_register(raw->handle, xfer);
if (ret) {
dev_dbg(dev,
"...retrying[%d] inflight registration\n",
retry);
msleep(raw->desc->max_rx_timeout_ms /
SCMI_XFER_RAW_MAX_RETRIES);
}
} while (ret && --retry);
if (ret) {
dev_warn(dev,
"RAW - Could NOT register xfer %d in-flight HDR:0x%08X\n",
xfer->hdr.seq, msg_hdr);
scmi_xfer_raw_put(raw->handle, xfer);
}
return ret;
}
/**
* scmi_do_xfer_raw_start - An helper to send a valid raw xfer
*
* @raw: A reference to the Raw instance.
* @xfer: The xfer to send
* @chan_id: The channel ID to use, if zero the channels is automatically
* selected based on the protocol used.
* @async: A flag stating if an asynchronous command is required.
*
* This function send a previously built raw xfer using an appropriate channel
* and queues the related waiting work.
*
* Note that we need to know explicitly if the required command is meant to be
* asynchronous in kind since we have to properly setup the waiter.
* (and deducing this from the payload is weak and do not scale given there is
* NOT a common header-flag stating if the command is asynchronous or not)
*
* Return: 0 on Success
*/
static int scmi_do_xfer_raw_start(struct scmi_raw_mode_info *raw,
struct scmi_xfer *xfer, u8 chan_id,
bool async)
{
int ret;
struct scmi_chan_info *cinfo;
struct scmi_xfer_raw_waiter *rw;
struct device *dev = raw->handle->dev;
if (!chan_id)
chan_id = xfer->hdr.protocol_id;
else
xfer->flags |= SCMI_XFER_FLAG_CHAN_SET;
cinfo = scmi_xfer_raw_channel_get(raw->handle, chan_id);
if (IS_ERR(cinfo))
return PTR_ERR(cinfo);
rw = scmi_xfer_raw_waiter_get(raw, xfer, cinfo, async);
if (!rw) {
dev_warn(dev, "RAW - Cannot get a free waiter !\n");
return -ENOMEM;
}
/* True ONLY if also supported by transport. */
if (is_polling_enabled(cinfo, raw->desc))
xfer->hdr.poll_completion = true;
reinit_completion(&xfer->done);
/* Make sure xfer state update is visible before sending */
smp_store_mb(xfer->state, SCMI_XFER_SENT_OK);
trace_scmi_xfer_begin(xfer->transfer_id, xfer->hdr.id,
xfer->hdr.protocol_id, xfer->hdr.seq,
xfer->hdr.poll_completion);
ret = raw->desc->ops->send_message(rw->cinfo, xfer);
if (ret) {
dev_err(dev, "Failed to send RAW message %d\n", ret);
scmi_xfer_raw_waiter_put(raw, rw);
return ret;
}
trace_scmi_msg_dump(raw->id, cinfo->id, xfer->hdr.protocol_id,
xfer->hdr.id, "cmnd", xfer->hdr.seq,
xfer->hdr.status,
xfer->tx.buf, xfer->tx.len);
scmi_xfer_raw_waiter_enqueue(raw, rw);
return ret;
}
/**
* scmi_raw_message_send - An helper to build and send an SCMI command using
* the provided SCMI bare message buffer
*
* @raw: A reference to the Raw instance.
* @buf: A buffer containing the whole SCMI message to send (including the
* header) in little-endian binary format.
* @len: Length of the message in @buf.
* @chan_id: The channel ID to use.
* @async: A flag stating if an asynchronous command is required.
*
* Return: 0 on Success
*/
static int scmi_raw_message_send(struct scmi_raw_mode_info *raw,
void *buf, size_t len, u8 chan_id, bool async)
{
int ret;
struct scmi_xfer *xfer;
ret = scmi_xfer_raw_get_init(raw, buf, len, &xfer);
if (ret)
return ret;
ret = scmi_do_xfer_raw_start(raw, xfer, chan_id, async);
if (ret)
scmi_xfer_raw_put(raw->handle, xfer);
return ret;
}
static struct scmi_raw_buffer *
scmi_raw_message_dequeue(struct scmi_raw_queue *q, bool o_nonblock)
{
unsigned long flags;
struct scmi_raw_buffer *rb;
spin_lock_irqsave(&q->msg_q_lock, flags);
while (list_empty(&q->msg_q)) {
spin_unlock_irqrestore(&q->msg_q_lock, flags);
if (o_nonblock)
return ERR_PTR(-EAGAIN);
if (wait_event_interruptible(q->wq, !list_empty(&q->msg_q)))
return ERR_PTR(-ERESTARTSYS);
spin_lock_irqsave(&q->msg_q_lock, flags);
}
rb = scmi_raw_buffer_dequeue_unlocked(q);
spin_unlock_irqrestore(&q->msg_q_lock, flags);
return rb;
}
/**
* scmi_raw_message_receive - An helper to dequeue and report the next
* available enqueued raw message payload that has been collected.
*
* @raw: A reference to the Raw instance.
* @buf: A buffer to get hold of the whole SCMI message received and represented
* in little-endian binary format.
* @len: Length of @buf.
* @size: The effective size of the message copied into @buf
* @idx: The index of the queue to pick the next queued message from.
* @chan_id: The channel ID to use.
* @o_nonblock: A flag to request a non-blocking message dequeue.
*
* Return: 0 on Success
*/
static int scmi_raw_message_receive(struct scmi_raw_mode_info *raw,
void *buf, size_t len, size_t *size,
unsigned int idx, unsigned int chan_id,
bool o_nonblock)
{
int ret = 0;
struct scmi_raw_buffer *rb;
struct scmi_raw_queue *q;
q = scmi_raw_queue_select(raw, idx, chan_id);
if (!q)
return -ENODEV;
rb = scmi_raw_message_dequeue(q, o_nonblock);
if (IS_ERR(rb)) {
dev_dbg(raw->handle->dev, "RAW - No message available!\n");
return PTR_ERR(rb);
}
if (rb->msg.len <= len) {
memcpy(buf, rb->msg.buf, rb->msg.len);
*size = rb->msg.len;
} else {
ret = -ENOSPC;
}
scmi_raw_buffer_put(q, rb);
return ret;
}
/* SCMI Raw debugfs helpers */
static ssize_t scmi_dbg_raw_mode_common_read(struct file *filp,
char __user *buf,
size_t count, loff_t *ppos,
unsigned int idx)
{
ssize_t cnt;
struct scmi_dbg_raw_data *rd = filp->private_data;
if (!rd->rx_size) {
int ret;
ret = scmi_raw_message_receive(rd->raw, rd->rx.buf, rd->rx.len,
&rd->rx_size, idx, rd->chan_id,
filp->f_flags & O_NONBLOCK);
if (ret) {
rd->rx_size = 0;
return ret;
}
/* Reset any previous filepos change, including writes */
*ppos = 0;
} else if (*ppos == rd->rx_size) {
/* Return EOF once all the message has been read-out */
rd->rx_size = 0;
return 0;
}
cnt = simple_read_from_buffer(buf, count, ppos,
rd->rx.buf, rd->rx_size);
return cnt;
}
static ssize_t scmi_dbg_raw_mode_common_write(struct file *filp,
const char __user *buf,
size_t count, loff_t *ppos,
bool async)
{
int ret;
struct scmi_dbg_raw_data *rd = filp->private_data;
if (count > rd->tx.len - rd->tx_size)
return -ENOSPC;
/* On first write attempt @count carries the total full message size. */
if (!rd->tx_size)
rd->tx_req_size = count;
/*
* Gather a full message, possibly across multiple interrupted wrrtes,
* before sending it with a single RAW xfer.
*/
if (rd->tx_size < rd->tx_req_size) {
size_t cnt;
cnt = simple_write_to_buffer(rd->tx.buf, rd->tx.len, ppos,
buf, count);
rd->tx_size += cnt;
if (cnt < count)
return cnt;
}
ret = scmi_raw_message_send(rd->raw, rd->tx.buf, rd->tx_size,
rd->chan_id, async);
/* Reset ppos for next message ... */
rd->tx_size = 0;
*ppos = 0;
return ret ?: count;
}
static __poll_t scmi_test_dbg_raw_common_poll(struct file *filp,
struct poll_table_struct *wait,
unsigned int idx)
{
unsigned long flags;
struct scmi_dbg_raw_data *rd = filp->private_data;
struct scmi_raw_queue *q;
__poll_t mask = 0;
q = scmi_raw_queue_select(rd->raw, idx, rd->chan_id);
if (!q)
return mask;
poll_wait(filp, &q->wq, wait);
spin_lock_irqsave(&q->msg_q_lock, flags);
if (!list_empty(&q->msg_q))
mask = EPOLLIN | EPOLLRDNORM;
spin_unlock_irqrestore(&q->msg_q_lock, flags);
return mask;
}
static ssize_t scmi_dbg_raw_mode_message_read(struct file *filp,
char __user *buf,
size_t count, loff_t *ppos)
{
return scmi_dbg_raw_mode_common_read(filp, buf, count, ppos,
SCMI_RAW_REPLY_QUEUE);
}
static ssize_t scmi_dbg_raw_mode_message_write(struct file *filp,
const char __user *buf,
size_t count, loff_t *ppos)
{
return scmi_dbg_raw_mode_common_write(filp, buf, count, ppos, false);
}
static __poll_t scmi_dbg_raw_mode_message_poll(struct file *filp,
struct poll_table_struct *wait)
{
return scmi_test_dbg_raw_common_poll(filp, wait, SCMI_RAW_REPLY_QUEUE);
}
static int scmi_dbg_raw_mode_open(struct inode *inode, struct file *filp)
{
u8 id;
struct scmi_raw_mode_info *raw;
struct scmi_dbg_raw_data *rd;
const char *id_str = filp->f_path.dentry->d_parent->d_name.name;
if (!inode->i_private)
return -ENODEV;
raw = inode->i_private;
rd = kzalloc(sizeof(*rd), GFP_KERNEL);
if (!rd)
return -ENOMEM;
rd->rx.len = raw->desc->max_msg_size + sizeof(u32);
rd->rx.buf = kzalloc(rd->rx.len, GFP_KERNEL);
if (!rd->rx.buf) {
kfree(rd);
return -ENOMEM;
}
rd->tx.len = raw->desc->max_msg_size + sizeof(u32);
rd->tx.buf = kzalloc(rd->tx.len, GFP_KERNEL);
if (!rd->tx.buf) {
kfree(rd->rx.buf);
kfree(rd);
return -ENOMEM;
}
/* Grab channel ID from debugfs entry naming if any */
if (!kstrtou8(id_str, 16, &id))
rd->chan_id = id;
rd->raw = raw;
filp->private_data = rd;
return 0;
}
static int scmi_dbg_raw_mode_release(struct inode *inode, struct file *filp)
{
struct scmi_dbg_raw_data *rd = filp->private_data;
kfree(rd->rx.buf);
kfree(rd->tx.buf);
kfree(rd);
return 0;
}
static ssize_t scmi_dbg_raw_mode_reset_write(struct file *filp,
const char __user *buf,
size_t count, loff_t *ppos)
{
struct scmi_dbg_raw_data *rd = filp->private_data;
scmi_xfer_raw_reset(rd->raw);
return count;
}
static const struct file_operations scmi_dbg_raw_mode_reset_fops = {
.open = scmi_dbg_raw_mode_open,
.release = scmi_dbg_raw_mode_release,
.write = scmi_dbg_raw_mode_reset_write,
.owner = THIS_MODULE,
};
static const struct file_operations scmi_dbg_raw_mode_message_fops = {
.open = scmi_dbg_raw_mode_open,
.release = scmi_dbg_raw_mode_release,
.read = scmi_dbg_raw_mode_message_read,
.write = scmi_dbg_raw_mode_message_write,
.poll = scmi_dbg_raw_mode_message_poll,
.owner = THIS_MODULE,
};
static ssize_t scmi_dbg_raw_mode_message_async_write(struct file *filp,
const char __user *buf,
size_t count, loff_t *ppos)
{
return scmi_dbg_raw_mode_common_write(filp, buf, count, ppos, true);
}
static const struct file_operations scmi_dbg_raw_mode_message_async_fops = {
.open = scmi_dbg_raw_mode_open,
.release = scmi_dbg_raw_mode_release,
.read = scmi_dbg_raw_mode_message_read,
.write = scmi_dbg_raw_mode_message_async_write,
.poll = scmi_dbg_raw_mode_message_poll,
.owner = THIS_MODULE,
};
static ssize_t scmi_test_dbg_raw_mode_notif_read(struct file *filp,
char __user *buf,
size_t count, loff_t *ppos)
{
return scmi_dbg_raw_mode_common_read(filp, buf, count, ppos,
SCMI_RAW_NOTIF_QUEUE);
}
static __poll_t
scmi_test_dbg_raw_mode_notif_poll(struct file *filp,
struct poll_table_struct *wait)
{
return scmi_test_dbg_raw_common_poll(filp, wait, SCMI_RAW_NOTIF_QUEUE);
}
static const struct file_operations scmi_dbg_raw_mode_notification_fops = {
.open = scmi_dbg_raw_mode_open,
.release = scmi_dbg_raw_mode_release,
.read = scmi_test_dbg_raw_mode_notif_read,
.poll = scmi_test_dbg_raw_mode_notif_poll,
.owner = THIS_MODULE,
};
static ssize_t scmi_test_dbg_raw_mode_errors_read(struct file *filp,
char __user *buf,
size_t count, loff_t *ppos)
{
return scmi_dbg_raw_mode_common_read(filp, buf, count, ppos,
SCMI_RAW_ERRS_QUEUE);
}
static __poll_t
scmi_test_dbg_raw_mode_errors_poll(struct file *filp,
struct poll_table_struct *wait)
{
return scmi_test_dbg_raw_common_poll(filp, wait, SCMI_RAW_ERRS_QUEUE);
}
static const struct file_operations scmi_dbg_raw_mode_errors_fops = {
.open = scmi_dbg_raw_mode_open,
.release = scmi_dbg_raw_mode_release,
.read = scmi_test_dbg_raw_mode_errors_read,
.poll = scmi_test_dbg_raw_mode_errors_poll,
.owner = THIS_MODULE,
};
static struct scmi_raw_queue *
scmi_raw_queue_init(struct scmi_raw_mode_info *raw)
{
int i;
struct scmi_raw_buffer *rb;
struct device *dev = raw->handle->dev;
struct scmi_raw_queue *q;
q = devm_kzalloc(dev, sizeof(*q), GFP_KERNEL);
if (!q)
return ERR_PTR(-ENOMEM);
rb = devm_kcalloc(dev, raw->tx_max_msg, sizeof(*rb), GFP_KERNEL);
if (!rb)
return ERR_PTR(-ENOMEM);
spin_lock_init(&q->free_bufs_lock);
INIT_LIST_HEAD(&q->free_bufs);
for (i = 0; i < raw->tx_max_msg; i++, rb++) {
rb->max_len = raw->desc->max_msg_size + sizeof(u32);
rb->msg.buf = devm_kzalloc(dev, rb->max_len, GFP_KERNEL);
if (!rb->msg.buf)
return ERR_PTR(-ENOMEM);
scmi_raw_buffer_put(q, rb);
}
spin_lock_init(&q->msg_q_lock);
INIT_LIST_HEAD(&q->msg_q);
init_waitqueue_head(&q->wq);
return q;
}
static int scmi_xfer_raw_worker_init(struct scmi_raw_mode_info *raw)
{
int i;
struct scmi_xfer_raw_waiter *rw;
struct device *dev = raw->handle->dev;
rw = devm_kcalloc(dev, raw->tx_max_msg, sizeof(*rw), GFP_KERNEL);
if (!rw)
return -ENOMEM;
raw->wait_wq = alloc_workqueue("scmi-raw-wait-wq-%d",
WQ_UNBOUND | WQ_FREEZABLE |
WQ_HIGHPRI | WQ_SYSFS, 0, raw->id);
if (!raw->wait_wq)
return -ENOMEM;
mutex_init(&raw->free_mtx);
INIT_LIST_HEAD(&raw->free_waiters);
mutex_init(&raw->active_mtx);
INIT_LIST_HEAD(&raw->active_waiters);
for (i = 0; i < raw->tx_max_msg; i++, rw++) {
init_completion(&rw->async_response);
scmi_xfer_raw_waiter_put(raw, rw);
}
INIT_WORK(&raw->waiters_work, scmi_xfer_raw_worker);
return 0;
}
static int scmi_raw_mode_setup(struct scmi_raw_mode_info *raw,
u8 *channels, int num_chans)
{
int ret, idx;
void *gid;
struct device *dev = raw->handle->dev;
gid = devres_open_group(dev, NULL, GFP_KERNEL);
if (!gid)
return -ENOMEM;
for (idx = 0; idx < SCMI_RAW_MAX_QUEUE; idx++) {
raw->q[idx] = scmi_raw_queue_init(raw);
if (IS_ERR(raw->q[idx])) {
ret = PTR_ERR(raw->q[idx]);
goto err;
}
}
xa_init(&raw->chans_q);
if (num_chans > 1) {
int i;
for (i = 0; i < num_chans; i++) {
void *xret;
struct scmi_raw_queue *q;
q = scmi_raw_queue_init(raw);
if (IS_ERR(q)) {
ret = PTR_ERR(q);
goto err_xa;
}
xret = xa_store(&raw->chans_q, channels[i], q,
GFP_KERNEL);
if (xa_err(xret)) {
dev_err(dev,
"Fail to allocate Raw queue 0x%02X\n",
channels[i]);
ret = xa_err(xret);
goto err_xa;
}
}
}
ret = scmi_xfer_raw_worker_init(raw);
if (ret)
goto err_xa;
devres_close_group(dev, gid);
raw->gid = gid;
return 0;
err_xa:
xa_destroy(&raw->chans_q);
err:
devres_release_group(dev, gid);
return ret;
}
/**
* scmi_raw_mode_init - Function to initialize the SCMI Raw stack
*
* @handle: Pointer to SCMI entity handle
* @top_dentry: A reference to the top Raw debugfs dentry
* @instance_id: The ID of the underlying SCMI platform instance represented by
* this Raw instance
* @channels: The list of the existing channels
* @num_chans: The number of entries in @channels
* @desc: Reference to the transport operations
* @tx_max_msg: Max number of in-flight messages allowed by the transport
*
* This function prepare the SCMI Raw stack and creates the debugfs API.
*
* Return: An opaque handle to the Raw instance on Success, an ERR_PTR otherwise
*/
void *scmi_raw_mode_init(const struct scmi_handle *handle,
struct dentry *top_dentry, int instance_id,
u8 *channels, int num_chans,
const struct scmi_desc *desc, int tx_max_msg)
{
int ret;
struct scmi_raw_mode_info *raw;
struct device *dev;
if (!handle || !desc)
return ERR_PTR(-EINVAL);
dev = handle->dev;
raw = devm_kzalloc(dev, sizeof(*raw), GFP_KERNEL);
if (!raw)
return ERR_PTR(-ENOMEM);
raw->handle = handle;
raw->desc = desc;
raw->tx_max_msg = tx_max_msg;
raw->id = instance_id;
ret = scmi_raw_mode_setup(raw, channels, num_chans);
if (ret) {
devm_kfree(dev, raw);
return ERR_PTR(ret);
}
raw->dentry = debugfs_create_dir("raw", top_dentry);
debugfs_create_file("reset", 0200, raw->dentry, raw,
&scmi_dbg_raw_mode_reset_fops);
debugfs_create_file("message", 0600, raw->dentry, raw,
&scmi_dbg_raw_mode_message_fops);
debugfs_create_file("message_async", 0600, raw->dentry, raw,
&scmi_dbg_raw_mode_message_async_fops);
debugfs_create_file("notification", 0400, raw->dentry, raw,
&scmi_dbg_raw_mode_notification_fops);
debugfs_create_file("errors", 0400, raw->dentry, raw,
&scmi_dbg_raw_mode_errors_fops);
/*
* Expose per-channel entries if multiple channels available.
* Just ignore errors while setting up these interfaces since we
* have anyway already a working core Raw support.
*/
if (num_chans > 1) {
int i;
struct dentry *top_chans;
top_chans = debugfs_create_dir("channels", raw->dentry);
for (i = 0; i < num_chans; i++) {
char cdir[8];
struct dentry *chd;
snprintf(cdir, 8, "0x%02X", channels[i]);
chd = debugfs_create_dir(cdir, top_chans);
debugfs_create_file("message", 0600, chd, raw,
&scmi_dbg_raw_mode_message_fops);
debugfs_create_file("message_async", 0600, chd, raw,
&scmi_dbg_raw_mode_message_async_fops);
}
}
dev_info(dev, "SCMI RAW Mode initialized for instance %d\n", raw->id);
return raw;
}
/**
* scmi_raw_mode_cleanup - Function to cleanup the SCMI Raw stack
*
* @r: An opaque handle to an initialized SCMI Raw instance
*/
void scmi_raw_mode_cleanup(void *r)
{
struct scmi_raw_mode_info *raw = r;
if (!raw)
return;
debugfs_remove_recursive(raw->dentry);
cancel_work_sync(&raw->waiters_work);
destroy_workqueue(raw->wait_wq);
xa_destroy(&raw->chans_q);
}
static int scmi_xfer_raw_collect(void *msg, size_t *msg_len,
struct scmi_xfer *xfer)
{
__le32 *m;
size_t msg_size;
if (!xfer || !msg || !msg_len)
return -EINVAL;
/* Account for hdr ...*/
msg_size = xfer->rx.len + sizeof(u32);
/* ... and status if needed */
if (xfer->hdr.type != MSG_TYPE_NOTIFICATION)
msg_size += sizeof(u32);
if (msg_size > *msg_len)
return -ENOSPC;
m = msg;
*m = cpu_to_le32(pack_scmi_header(&xfer->hdr));
if (xfer->hdr.type != MSG_TYPE_NOTIFICATION)
*++m = cpu_to_le32(xfer->hdr.status);
memcpy(++m, xfer->rx.buf, xfer->rx.len);
*msg_len = msg_size;
return 0;
}
/**
* scmi_raw_message_report - Helper to report back valid reponses/notifications
* to raw message requests.
*
* @r: An opaque reference to the raw instance configuration
* @xfer: The xfer containing the message to be reported
* @idx: The index of the queue.
* @chan_id: The channel ID to use.
*
* If Raw mode is enabled, this is called from the SCMI core on the regular RX
* path to save and enqueue the response/notification payload carried by this
* xfer into a dedicated scmi_raw_buffer for later consumption by the user.
*
* This way the caller can free the related xfer immediately afterwards and the
* user can read back the raw message payload at its own pace (if ever) without
* holding an xfer for too long.
*/
void scmi_raw_message_report(void *r, struct scmi_xfer *xfer,
unsigned int idx, unsigned int chan_id)
{
int ret;
unsigned long flags;
struct scmi_raw_buffer *rb;
struct device *dev;
struct scmi_raw_queue *q;
struct scmi_raw_mode_info *raw = r;
if (!raw || (idx == SCMI_RAW_REPLY_QUEUE && !SCMI_XFER_IS_RAW(xfer)))
return;
dev = raw->handle->dev;
q = scmi_raw_queue_select(raw, idx,
SCMI_XFER_IS_CHAN_SET(xfer) ? chan_id : 0);
/*
* Grab the msg_q_lock upfront to avoid a possible race between
* realizing the free list was empty and effectively picking the next
* buffer to use from the oldest one enqueued and still unread on this
* msg_q.
*
* Note that nowhere else these locks are taken together, so no risk of
* deadlocks du eto inversion.
*/
spin_lock_irqsave(&q->msg_q_lock, flags);
rb = scmi_raw_buffer_get(q);
if (!rb) {
/*
* Immediate and delayed replies to previously injected Raw
* commands MUST be read back from userspace to free the buffers:
* if this is not happening something is seriously broken and
* must be fixed at the application level: complain loudly.
*/
if (idx == SCMI_RAW_REPLY_QUEUE) {
spin_unlock_irqrestore(&q->msg_q_lock, flags);
dev_warn(dev,
"RAW[%d] - Buffers exhausted. Dropping report.\n",
idx);
return;
}
/*
* Notifications and errors queues are instead handled in a
* circular manner: unread old buffers are just overwritten by
* newer ones.
*
* The main reason for this is that notifications originated
* by Raw requests cannot be distinguished from normal ones, so
* your Raw buffers queues risk to be flooded and depleted by
* notifications if you left it mistakenly enabled or when in
* coexistence mode.
*/
rb = scmi_raw_buffer_dequeue_unlocked(q);
if (WARN_ON(!rb)) {
spin_unlock_irqrestore(&q->msg_q_lock, flags);
return;
}
/* Reset to full buffer length */
rb->msg.len = rb->max_len;
dev_warn_once(dev,
"RAW[%d] - Buffers exhausted. Re-using oldest.\n",
idx);
}
spin_unlock_irqrestore(&q->msg_q_lock, flags);
ret = scmi_xfer_raw_collect(rb->msg.buf, &rb->msg.len, xfer);
if (ret) {
dev_warn(dev, "RAW - Cannot collect xfer into buffer !\n");
scmi_raw_buffer_put(q, rb);
return;
}
scmi_raw_buffer_enqueue(q, rb);
}
static void scmi_xfer_raw_fill(struct scmi_raw_mode_info *raw,
struct scmi_chan_info *cinfo,
struct scmi_xfer *xfer, u32 msg_hdr)
{
/* Unpack received HDR as it is */
unpack_scmi_header(msg_hdr, &xfer->hdr);
xfer->hdr.seq = MSG_XTRACT_TOKEN(msg_hdr);
memset(xfer->rx.buf, 0x00, xfer->rx.len);
raw->desc->ops->fetch_response(cinfo, xfer);
}
/**
* scmi_raw_error_report - Helper to report back timed-out or generally
* unexpected replies.
*
* @r: An opaque reference to the raw instance configuration
* @cinfo: A reference to the channel to use to retrieve the broken xfer
* @msg_hdr: The SCMI message header of the message to fetch and report
* @priv: Any private data related to the xfer.
*
* If Raw mode is enabled, this is called from the SCMI core on the RX path in
* case of errors to save and enqueue the bad message payload carried by the
* message that has just been received.
*
* Note that we have to manually fetch any available payload into a temporary
* xfer to be able to save and enqueue the message, since the regular RX error
* path which had called this would have not fetched the message payload having
* classified it as an error.
*/
void scmi_raw_error_report(void *r, struct scmi_chan_info *cinfo,
u32 msg_hdr, void *priv)
{
struct scmi_xfer xfer;
struct scmi_raw_mode_info *raw = r;
if (!raw)
return;
xfer.rx.len = raw->desc->max_msg_size;
xfer.rx.buf = kzalloc(xfer.rx.len, GFP_ATOMIC);
if (!xfer.rx.buf) {
dev_info(raw->handle->dev,
"Cannot report Raw error for HDR:0x%X - ENOMEM\n",
msg_hdr);
return;
}
/* Any transport-provided priv must be passed back down to transport */
if (priv)
/* Ensure priv is visible */
smp_store_mb(xfer.priv, priv);
scmi_xfer_raw_fill(raw, cinfo, &xfer, msg_hdr);
scmi_raw_message_report(raw, &xfer, SCMI_RAW_ERRS_QUEUE, 0);
kfree(xfer.rx.buf);
}