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mirror_ubuntu-kernels/drivers/firmware/arm_scmi/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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/bitmap.h>
#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/export.h>
#include <linux/idr.h>
#include <linux/io.h>
#include <linux/io-64-nonatomic-hi-lo.h>
#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/hashtable.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/processor.h>
#include <linux/refcount.h>
#include <linux/slab.h>
#include "common.h"
#include "notify.h"
#include "raw_mode.h"
#define CREATE_TRACE_POINTS
#include <trace/events/scmi.h>
static DEFINE_IDA(scmi_id);
static DEFINE_IDR(scmi_protocols);
static DEFINE_SPINLOCK(protocol_lock);
/* 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 struct dentry *scmi_top_dentry;
/**
* 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.
* @version: Protocol version supported by the platform as detected at runtime.
* @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;
unsigned int version;
struct scmi_protocol_handle ph;
};
#define ph_to_pi(h) container_of(h, struct scmi_protocol_instance, ph)
/**
* struct scmi_debug_info - Debug common info
* @top_dentry: A reference to the top debugfs dentry
* @name: Name of this SCMI instance
* @type: Type of this SCMI instance
* @is_atomic: Flag to state if the transport of this instance is atomic
*/
struct scmi_debug_info {
struct dentry *top_dentry;
const char *name;
const char *type;
bool is_atomic;
};
/**
* struct scmi_info - Structure representing a SCMI instance
*
* @id: A sequence number starting from zero identifying this 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
* scmi_revision_info.num_protocols 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.
* @atomic_threshold: Optional system wide DT-configured threshold, expressed
* in microseconds, for atomic operations.
* Only SCMI synchronous commands reported by the platform
* to have an execution latency lesser-equal to the threshold
* should be considered for atomic mode operation: such
* decision is finally left up to the SCMI drivers.
* @notify_priv: Pointer to private data structure specific to notifications.
* @node: List head
* @users: Number of users of this instance
* @bus_nb: A notifier to listen for device bind/unbind on the scmi bus
* @dev_req_nb: A notifier to listen for device request/unrequest on the scmi
* bus
* @devreq_mtx: A mutex to serialize device creation for this SCMI instance
* @dbg: A pointer to debugfs related data (if any)
* @raw: An opaque reference handle used by SCMI Raw mode.
*/
struct scmi_info {
int id;
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;
unsigned int atomic_threshold;
void *notify_priv;
struct list_head node;
int users;
struct notifier_block bus_nb;
struct notifier_block dev_req_nb;
/* Serialize device creation process for this instance */
struct mutex devreq_mtx;
struct scmi_debug_info *dbg;
void *raw;
};
#define handle_to_scmi_info(h) container_of(h, struct scmi_info, handle)
#define bus_nb_to_scmi_info(nb) container_of(nb, struct scmi_info, bus_nb)
#define req_nb_to_scmi_info(nb) container_of(nb, struct scmi_info, dev_req_nb)
static const struct scmi_protocol *scmi_protocol_get(int protocol_id)
{
const struct scmi_protocol *proto;
proto = idr_find(&scmi_protocols, protocol_id);
if (!proto || !try_module_get(proto->owner)) {
pr_warn("SCMI Protocol 0x%x not found!\n", protocol_id);
return NULL;
}
pr_debug("Found SCMI Protocol 0x%x\n", protocol_id);
return proto;
}
static void scmi_protocol_put(int protocol_id)
{
const struct scmi_protocol *proto;
proto = idr_find(&scmi_protocols, protocol_id);
if (proto)
module_put(proto->owner);
}
int scmi_protocol_register(const struct scmi_protocol *proto)
{
int ret;
if (!proto) {
pr_err("invalid protocol\n");
return -EINVAL;
}
if (!proto->instance_init) {
pr_err("missing init for protocol 0x%x\n", proto->id);
return -EINVAL;
}
spin_lock(&protocol_lock);
ret = idr_alloc(&scmi_protocols, (void *)proto,
proto->id, proto->id + 1, GFP_ATOMIC);
spin_unlock(&protocol_lock);
if (ret != proto->id) {
pr_err("unable to allocate SCMI idr slot for 0x%x - err %d\n",
proto->id, ret);
return ret;
}
pr_debug("Registered SCMI Protocol 0x%x\n", proto->id);
return 0;
}
EXPORT_SYMBOL_GPL(scmi_protocol_register);
void scmi_protocol_unregister(const struct scmi_protocol *proto)
{
spin_lock(&protocol_lock);
idr_remove(&scmi_protocols, proto->id);
spin_unlock(&protocol_lock);
pr_debug("Unregistered SCMI Protocol 0x%x\n", proto->id);
}
EXPORT_SYMBOL_GPL(scmi_protocol_unregister);
/**
* scmi_create_protocol_devices - Create devices for all pending requests for
* this SCMI instance.
*
* @np: The device node describing the protocol
* @info: The SCMI instance descriptor
* @prot_id: The protocol ID
* @name: The optional name of the device to be created: if not provided this
* call will lead to the creation of all the devices currently requested
* for the specified protocol.
*/
static void scmi_create_protocol_devices(struct device_node *np,
struct scmi_info *info,
int prot_id, const char *name)
{
struct scmi_device *sdev;
mutex_lock(&info->devreq_mtx);
sdev = scmi_device_create(np, info->dev, prot_id, name);
if (name && !sdev)
dev_err(info->dev,
"failed to create device for protocol 0x%X (%s)\n",
prot_id, name);
mutex_unlock(&info->devreq_mtx);
}
static void scmi_destroy_protocol_devices(struct scmi_info *info,
int prot_id, const char *name)
{
mutex_lock(&info->devreq_mtx);
scmi_device_destroy(info->dev, prot_id, name);
mutex_unlock(&info->devreq_mtx);
}
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);
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_inflight_register_unlocked - Register the xfer as in-flight
*
* @xfer: The xfer to register
* @minfo: Pointer to Tx/Rx Message management info based on channel type
*
* Note that this helper assumes that the xfer to be registered as in-flight
* had been built using an xfer sequence number which still corresponds to a
* free slot in the xfer_alloc_table.
*
* Context: Assumes to be called with @xfer_lock already acquired.
*/
static inline void
scmi_xfer_inflight_register_unlocked(struct scmi_xfer *xfer,
struct scmi_xfers_info *minfo)
{
/* Set in-flight */
set_bit(xfer->hdr.seq, minfo->xfer_alloc_table);
hash_add(minfo->pending_xfers, &xfer->node, xfer->hdr.seq);
xfer->pending = true;
}
/**
* scmi_xfer_inflight_register - Try to register an xfer as in-flight
*
* @xfer: The xfer to register
* @minfo: Pointer to Tx/Rx Message management info based on channel type
*
* Note that this helper does NOT assume anything about the sequence number
* that was baked into the provided xfer, so it checks at first if it can
* be mapped to a free slot and fails with an error if another xfer with the
* same sequence number is currently still registered as in-flight.
*
* Return: 0 on Success or -EBUSY if sequence number embedded in the xfer
* could not rbe mapped to a free slot in the xfer_alloc_table.
*/
static int scmi_xfer_inflight_register(struct scmi_xfer *xfer,
struct scmi_xfers_info *minfo)
{
int ret = 0;
unsigned long flags;
spin_lock_irqsave(&minfo->xfer_lock, flags);
if (!test_bit(xfer->hdr.seq, minfo->xfer_alloc_table))
scmi_xfer_inflight_register_unlocked(xfer, minfo);
else
ret = -EBUSY;
spin_unlock_irqrestore(&minfo->xfer_lock, flags);
return ret;
}
/**
* scmi_xfer_raw_inflight_register - An helper to register the given xfer as in
* flight on the TX channel, if possible.
*
* @handle: Pointer to SCMI entity handle
* @xfer: The xfer to register
*
* Return: 0 on Success, error otherwise
*/
int scmi_xfer_raw_inflight_register(const struct scmi_handle *handle,
struct scmi_xfer *xfer)
{
struct scmi_info *info = handle_to_scmi_info(handle);
return scmi_xfer_inflight_register(xfer, &info->tx_minfo);
}
/**
* scmi_xfer_pending_set - Pick a proper sequence number and mark the xfer
* as pending in-flight
*
* @xfer: The xfer to act upon
* @minfo: Pointer to Tx/Rx Message management info based on channel type
*
* Return: 0 on Success or error otherwise
*/
static inline int scmi_xfer_pending_set(struct scmi_xfer *xfer,
struct scmi_xfers_info *minfo)
{
int ret;
unsigned long flags;
spin_lock_irqsave(&minfo->xfer_lock, flags);
/* Set a new monotonic token as the xfer sequence number */
ret = scmi_xfer_token_set(minfo, xfer);
if (!ret)
scmi_xfer_inflight_register_unlocked(xfer, minfo);
spin_unlock_irqrestore(&minfo->xfer_lock, flags);
return ret;
}
/**
* 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.
*
* Picks an xfer from the free list @free_xfers (if any available) and perform
* a basic initialization.
*
* Note that, at this point, still no sequence number is assigned to the
* allocated xfer, nor it is registered as a pending transaction.
*
* The successfully initialized xfer is refcounted.
*
* Context: Holds @xfer_lock while manipulating @free_xfers.
*
* Return: An initialized xfer if all went fine, else pointer error.
*/
static struct scmi_xfer *scmi_xfer_get(const struct scmi_handle *handle,
struct scmi_xfers_info *minfo)
{
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);
refcount_set(&xfer->users, 1);
atomic_set(&xfer->busy, SCMI_XFER_FREE);
spin_unlock_irqrestore(&minfo->xfer_lock, flags);
return xfer;
}
/**
* scmi_xfer_raw_get - Helper to get a bare free xfer from the TX channel
*
* @handle: Pointer to SCMI entity handle
*
* Note that xfer is taken from the TX channel structures.
*
* Return: A valid xfer on Success, or an error-pointer otherwise
*/
struct scmi_xfer *scmi_xfer_raw_get(const struct scmi_handle *handle)
{
struct scmi_xfer *xfer;
struct scmi_info *info = handle_to_scmi_info(handle);
xfer = scmi_xfer_get(handle, &info->tx_minfo);
if (!IS_ERR(xfer))
xfer->flags |= SCMI_XFER_FLAG_IS_RAW;
return xfer;
}
/**
* scmi_xfer_raw_channel_get - Helper to get a reference to the proper channel
* to use for a specific protocol_id Raw transaction.
*
* @handle: Pointer to SCMI entity handle
* @protocol_id: Identifier of the protocol
*
* Note that in a regular SCMI stack, usually, a protocol has to be defined in
* the DT to have an associated channel and be usable; but in Raw mode any
* protocol in range is allowed, re-using the Base channel, so as to enable
* fuzzing on any protocol without the need of a fully compiled DT.
*
* Return: A reference to the channel to use, or an ERR_PTR
*/
struct scmi_chan_info *
scmi_xfer_raw_channel_get(const struct scmi_handle *handle, u8 protocol_id)
{
struct scmi_chan_info *cinfo;
struct scmi_info *info = handle_to_scmi_info(handle);
cinfo = idr_find(&info->tx_idr, protocol_id);
if (!cinfo) {
if (protocol_id == SCMI_PROTOCOL_BASE)
return ERR_PTR(-EINVAL);
/* Use Base channel for protocols not defined for DT */
cinfo = idr_find(&info->tx_idr, SCMI_PROTOCOL_BASE);
if (!cinfo)
return ERR_PTR(-EINVAL);
dev_warn_once(handle->dev,
"Using Base channel for protocol 0x%X\n",
protocol_id);
}
return cinfo;
}
/**
* __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_raw_put - Release an xfer that was taken by @scmi_xfer_raw_get
*
* @handle: Pointer to SCMI entity handle
* @xfer: A reference to the xfer to put
*
* Note that as with other xfer_put() handlers the xfer is really effectively
* released only if there are no more users on the system.
*/
void scmi_xfer_raw_put(const struct scmi_handle *handle, struct scmi_xfer *xfer)
{
struct scmi_info *info = handle_to_scmi_info(handle);
xfer->flags &= ~SCMI_XFER_FLAG_IS_RAW;
xfer->flags &= ~SCMI_XFER_FLAG_CHAN_SET;
return __scmi_xfer_put(&info->tx_minfo, xfer);
}
/**
* 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);
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)
/* Ensure order between xfer->priv store and following ops */
smp_store_mb(xfer->priv, priv);
info->desc->ops->fetch_notification(cinfo, info->desc->max_msg_size,
xfer);
trace_scmi_msg_dump(info->id, cinfo->id, xfer->hdr.protocol_id,
xfer->hdr.id, "NOTI", xfer->hdr.seq,
xfer->hdr.status, xfer->rx.buf, xfer->rx.len);
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);
if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
xfer->hdr.seq = MSG_XTRACT_TOKEN(msg_hdr);
scmi_raw_message_report(info->raw, xfer, SCMI_RAW_NOTIF_QUEUE,
cinfo->id);
}
__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)) {
if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT))
scmi_raw_error_report(info->raw, cinfo, msg_hdr, priv);
if (MSG_XTRACT_TYPE(msg_hdr) == MSG_TYPE_DELAYED_RESP)
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)
/* Ensure order between xfer->priv store and following ops */
smp_store_mb(xfer->priv, priv);
info->desc->ops->fetch_response(cinfo, xfer);
trace_scmi_msg_dump(info->id, cinfo->id, xfer->hdr.protocol_id,
xfer->hdr.id,
xfer->hdr.type == MSG_TYPE_DELAYED_RESP ?
(!SCMI_XFER_IS_RAW(xfer) ? "DLYD" : "dlyd") :
(!SCMI_XFER_IS_RAW(xfer) ? "RESP" : "resp"),
xfer->hdr.seq, xfer->hdr.status,
xfer->rx.buf, xfer->rx.len);
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);
}
if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
/*
* When in polling mode avoid to queue the Raw xfer on the IRQ
* RX path since it will be already queued at the end of the TX
* poll loop.
*/
if (!xfer->hdr.poll_completion)
scmi_raw_message_report(info->raw, xfer,
SCMI_RAW_REPLY_QUEUE,
cinfo->id);
}
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);
}
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);
}
static int scmi_wait_for_reply(struct device *dev, const struct scmi_desc *desc,
struct scmi_chan_info *cinfo,
struct scmi_xfer *xfer, unsigned int timeout_ms)
{
int ret = 0;
if (xfer->hdr.poll_completion) {
/*
* Real polling is needed only if transport has NOT declared
* itself to support synchronous commands replies.
*/
if (!desc->sync_cmds_completed_on_ret) {
/*
* Poll on xfer using transport provided .poll_done();
* assumes no completion interrupt was available.
*/
ktime_t stop = ktime_add_ms(ktime_get(), timeout_ms);
spin_until_cond(scmi_xfer_done_no_timeout(cinfo,
xfer, stop));
if (ktime_after(ktime_get(), stop)) {
dev_err(dev,
"timed out in resp(caller: %pS) - polling\n",
(void *)_RET_IP_);
ret = -ETIMEDOUT;
}
}
if (!ret) {
unsigned long flags;
struct scmi_info *info =
handle_to_scmi_info(cinfo->handle);
/*
* 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) {
desc->ops->fetch_response(cinfo, xfer);
xfer->state = SCMI_XFER_RESP_OK;
}
spin_unlock_irqrestore(&xfer->lock, flags);
/* Trace polled replies. */
trace_scmi_msg_dump(info->id, cinfo->id,
xfer->hdr.protocol_id, xfer->hdr.id,
!SCMI_XFER_IS_RAW(xfer) ?
"RESP" : "resp",
xfer->hdr.seq, xfer->hdr.status,
xfer->rx.buf, xfer->rx.len);
if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
struct scmi_info *info =
handle_to_scmi_info(cinfo->handle);
scmi_raw_message_report(info->raw, xfer,
SCMI_RAW_REPLY_QUEUE,
cinfo->id);
}
}
} else {
/* And we wait for the response. */
if (!wait_for_completion_timeout(&xfer->done,
msecs_to_jiffies(timeout_ms))) {
dev_err(dev, "timed out in resp(caller: %pS)\n",
(void *)_RET_IP_);
ret = -ETIMEDOUT;
}
}
return ret;
}
/**
* scmi_wait_for_message_response - An helper to group all the possible ways of
* waiting for a synchronous message response.
*
* @cinfo: SCMI channel info
* @xfer: Reference to the transfer being waited for.
*
* Chooses waiting strategy (sleep-waiting vs busy-waiting) depending on
* configuration flags like xfer->hdr.poll_completion.
*
* Return: 0 on Success, error otherwise.
*/
static int scmi_wait_for_message_response(struct scmi_chan_info *cinfo,
struct scmi_xfer *xfer)
{
struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
struct device *dev = info->dev;
trace_scmi_xfer_response_wait(xfer->transfer_id, xfer->hdr.id,
xfer->hdr.protocol_id, xfer->hdr.seq,
info->desc->max_rx_timeout_ms,
xfer->hdr.poll_completion);
return scmi_wait_for_reply(dev, info->desc, cinfo, xfer,
info->desc->max_rx_timeout_ms);
}
/**
* scmi_xfer_raw_wait_for_message_response - An helper to wait for a message
* reply to an xfer raw request on a specific channel for the required timeout.
*
* @cinfo: SCMI channel info
* @xfer: Reference to the transfer being waited for.
* @timeout_ms: The maximum timeout in milliseconds
*
* Return: 0 on Success, error otherwise.
*/
int scmi_xfer_raw_wait_for_message_response(struct scmi_chan_info *cinfo,
struct scmi_xfer *xfer,
unsigned int timeout_ms)
{
int ret;
struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
struct device *dev = info->dev;
ret = scmi_wait_for_reply(dev, info->desc, cinfo, xfer, timeout_ms);
if (ret)
dev_dbg(dev, "timed out in RAW response - HDR:%08X\n",
pack_scmi_header(&xfer->hdr));
return ret;
}
/**
* 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;
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;
/* Check for polling request on custom command xfers at first */
if (xfer->hdr.poll_completion &&
!is_transport_polling_capable(info->desc)) {
dev_warn_once(dev,
"Polling mode is not supported by transport.\n");
return -EINVAL;
}
cinfo = idr_find(&info->tx_idr, pi->proto->id);
if (unlikely(!cinfo))
return -EINVAL;
/* True ONLY if also supported by transport. */
if (is_polling_enabled(cinfo, info->desc))
xfer->hdr.poll_completion = true;
/*
* 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);
trace_scmi_xfer_begin(xfer->transfer_id, xfer->hdr.id,
xfer->hdr.protocol_id, xfer->hdr.seq,
xfer->hdr.poll_completion);
/* Clear any stale status */
xfer->hdr.status = SCMI_SUCCESS;
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;
}
trace_scmi_msg_dump(info->id, cinfo->id, xfer->hdr.protocol_id,
xfer->hdr.id, "CMND", xfer->hdr.seq,
xfer->hdr.status, xfer->tx.buf, xfer->tx.len);
ret = scmi_wait_for_message_response(cinfo, xfer);
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, xfer);
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;
}
/**
* 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
*
* Using asynchronous commands in atomic/polling mode should be avoided since
* it could cause long busy-waiting here, so ignore polling for the delayed
* response and WARN if it was requested for this command transaction since
* upper layers should refrain from issuing such kind of requests.
*
* The only other option would have been to refrain from using any asynchronous
* command even if made available, when an atomic transport is detected, and
* instead forcibly use the synchronous version (thing that can be easily
* attained at the protocol layer), but this would also have led to longer
* stalls of the channel for synchronous commands and possibly timeouts.
* (in other words there is usually a good reason if a platform provides an
* asynchronous version of a command and we should prefer to use it...just not
* when using atomic/polling mode)
*
* 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;
/*
* Delayed responses should not be polled, so an async command should
* not have been used when requiring an atomic/poll context; WARN and
* perform instead a sleeping wait.
* (Note Async + IgnoreDelayedResponses are sent via do_xfer)
*/
WARN_ON_ONCE(xfer->hdr.poll_completion);
ret = do_xfer(ph, xfer);
if (!ret) {
if (!wait_for_completion_timeout(xfer->async_done, timeout)) {
dev_err(ph->dev,
"timed out in delayed resp(caller: %pS)\n",
(void *)_RET_IP_);
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);
if (IS_ERR(xfer)) {
ret = PTR_ERR(xfer);
dev_err(dev, "failed to get free message slot(%d)\n", ret);
return ret;
}
/* Pick a sequence number and register this xfer as in-flight */
ret = scmi_xfer_pending_set(xfer, minfo);
if (ret) {
dev_err(pi->handle->dev,
"Failed to get monotonic token %d\n", ret);
__scmi_xfer_put(minfo, xfer);
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.
* @version: The detected protocol version for the core to register.
*
* Return: 0 on Success
*/
static int scmi_set_protocol_priv(const struct scmi_protocol_handle *ph,
void *priv, u32 version)
{
struct scmi_protocol_instance *pi = ph_to_pi(ph);
pi->priv = priv;
pi->version = version;
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,
.xfer_put = xfer_put,
};
struct scmi_msg_resp_domain_name_get {
__le32 flags;
u8 name[SCMI_MAX_STR_SIZE];
};
/**
* scmi_common_extended_name_get - Common helper to get extended resources name
* @ph: A protocol handle reference.
* @cmd_id: The specific command ID to use.
* @res_id: The specific resource ID to use.
* @flags: A pointer to specific flags to use, if any.
* @name: A pointer to the preallocated area where the retrieved name will be
* stored as a NULL terminated string.
* @len: The len in bytes of the @name char array.
*
* Return: 0 on Succcess
*/
static int scmi_common_extended_name_get(const struct scmi_protocol_handle *ph,
u8 cmd_id, u32 res_id, u32 *flags,
char *name, size_t len)
{
int ret;
size_t txlen;
struct scmi_xfer *t;
struct scmi_msg_resp_domain_name_get *resp;
txlen = !flags ? sizeof(res_id) : sizeof(res_id) + sizeof(*flags);
ret = ph->xops->xfer_get_init(ph, cmd_id, txlen, sizeof(*resp), &t);
if (ret)
goto out;
put_unaligned_le32(res_id, t->tx.buf);
if (flags)
put_unaligned_le32(*flags, t->tx.buf + sizeof(res_id));
resp = t->rx.buf;
ret = ph->xops->do_xfer(ph, t);
if (!ret)
strscpy(name, resp->name, len);
ph->xops->xfer_put(ph, t);
out:
if (ret)
dev_warn(ph->dev,
"Failed to get extended name - id:%u (ret:%d). Using %s\n",
res_id, ret, name);
return ret;
}
/**
* struct scmi_iterator - Iterator descriptor
* @msg: A reference to the message TX buffer; filled by @prepare_message with
* a proper custom command payload for each multi-part command request.
* @resp: A reference to the response RX buffer; used by @update_state and
* @process_response to parse the multi-part replies.
* @t: A reference to the underlying xfer initialized and used transparently by
* the iterator internal routines.
* @ph: A reference to the associated protocol handle to be used.
* @ops: A reference to the custom provided iterator operations.
* @state: The current iterator state; used and updated in turn by the iterators
* internal routines and by the caller-provided @scmi_iterator_ops.
* @priv: A reference to optional private data as provided by the caller and
* passed back to the @@scmi_iterator_ops.
*/
struct scmi_iterator {
void *msg;
void *resp;
struct scmi_xfer *t;
const struct scmi_protocol_handle *ph;
struct scmi_iterator_ops *ops;
struct scmi_iterator_state state;
void *priv;
};
static void *scmi_iterator_init(const struct scmi_protocol_handle *ph,
struct scmi_iterator_ops *ops,
unsigned int max_resources, u8 msg_id,
size_t tx_size, void *priv)
{
int ret;
struct scmi_iterator *i;
i = devm_kzalloc(ph->dev, sizeof(*i), GFP_KERNEL);
if (!i)
return ERR_PTR(-ENOMEM);
i->ph = ph;
i->ops = ops;
i->priv = priv;
ret = ph->xops->xfer_get_init(ph, msg_id, tx_size, 0, &i->t);
if (ret) {
devm_kfree(ph->dev, i);
return ERR_PTR(ret);
}
i->state.max_resources = max_resources;
i->msg = i->t->tx.buf;
i->resp = i->t->rx.buf;
return i;
}
static int scmi_iterator_run(void *iter)
{
int ret = -EINVAL;
struct scmi_iterator_ops *iops;
const struct scmi_protocol_handle *ph;
struct scmi_iterator_state *st;
struct scmi_iterator *i = iter;
if (!i || !i->ops || !i->ph)
return ret;
iops = i->ops;
ph = i->ph;
st = &i->state;
do {
iops->prepare_message(i->msg, st->desc_index, i->priv);
ret = ph->xops->do_xfer(ph, i->t);
if (ret)
break;
st->rx_len = i->t->rx.len;
ret = iops->update_state(st, i->resp, i->priv);
if (ret)
break;
if (st->num_returned > st->max_resources - st->desc_index) {
dev_err(ph->dev,
"No. of resources can't exceed %d\n",
st->max_resources);
ret = -EINVAL;
break;
}
for (st->loop_idx = 0; st->loop_idx < st->num_returned;
st->loop_idx++) {
ret = iops->process_response(ph, i->resp, st, i->priv);
if (ret)
goto out;
}
st->desc_index += st->num_returned;
ph->xops->reset_rx_to_maxsz(ph, i->t);
/*
* check for both returned and remaining to avoid infinite
* loop due to buggy firmware
*/
} while (st->num_returned && st->num_remaining);
out:
/* Finalize and destroy iterator */
ph->xops->xfer_put(ph, i->t);
devm_kfree(ph->dev, i);
return ret;
}
struct scmi_msg_get_fc_info {
__le32 domain;
__le32 message_id;
};
struct scmi_msg_resp_desc_fc {
__le32 attr;
#define SUPPORTS_DOORBELL(x) ((x) & BIT(0))
#define DOORBELL_REG_WIDTH(x) FIELD_GET(GENMASK(2, 1), (x))
__le32 rate_limit;
__le32 chan_addr_low;
__le32 chan_addr_high;
__le32 chan_size;
__le32 db_addr_low;
__le32 db_addr_high;
__le32 db_set_lmask;
__le32 db_set_hmask;
__le32 db_preserve_lmask;
__le32 db_preserve_hmask;
};
static void
scmi_common_fastchannel_init(const struct scmi_protocol_handle *ph,
u8 describe_id, u32 message_id, u32 valid_size,
u32 domain, void __iomem **p_addr,
struct scmi_fc_db_info **p_db)
{
int ret;
u32 flags;
u64 phys_addr;
u8 size;
void __iomem *addr;
struct scmi_xfer *t;
struct scmi_fc_db_info *db = NULL;
struct scmi_msg_get_fc_info *info;
struct scmi_msg_resp_desc_fc *resp;
const struct scmi_protocol_instance *pi = ph_to_pi(ph);
if (!p_addr) {
ret = -EINVAL;
goto err_out;
}
ret = ph->xops->xfer_get_init(ph, describe_id,
sizeof(*info), sizeof(*resp), &t);
if (ret)
goto err_out;
info = t->tx.buf;
info->domain = cpu_to_le32(domain);
info->message_id = cpu_to_le32(message_id);
/*
* Bail out on error leaving fc_info addresses zeroed; this includes
* the case in which the requested domain/message_id does NOT support
* fastchannels at all.
*/
ret = ph->xops->do_xfer(ph, t);
if (ret)
goto err_xfer;
resp = t->rx.buf;
flags = le32_to_cpu(resp->attr);
size = le32_to_cpu(resp->chan_size);
if (size != valid_size) {
ret = -EINVAL;
goto err_xfer;
}
phys_addr = le32_to_cpu(resp->chan_addr_low);
phys_addr |= (u64)le32_to_cpu(resp->chan_addr_high) << 32;
addr = devm_ioremap(ph->dev, phys_addr, size);
if (!addr) {
ret = -EADDRNOTAVAIL;
goto err_xfer;
}
*p_addr = addr;
if (p_db && SUPPORTS_DOORBELL(flags)) {
db = devm_kzalloc(ph->dev, sizeof(*db), GFP_KERNEL);
if (!db) {
ret = -ENOMEM;
goto err_db;
}
size = 1 << DOORBELL_REG_WIDTH(flags);
phys_addr = le32_to_cpu(resp->db_addr_low);
phys_addr |= (u64)le32_to_cpu(resp->db_addr_high) << 32;
addr = devm_ioremap(ph->dev, phys_addr, size);
if (!addr) {
ret = -EADDRNOTAVAIL;
goto err_db_mem;
}
db->addr = addr;
db->width = size;
db->set = le32_to_cpu(resp->db_set_lmask);
db->set |= (u64)le32_to_cpu(resp->db_set_hmask) << 32;
db->mask = le32_to_cpu(resp->db_preserve_lmask);
db->mask |= (u64)le32_to_cpu(resp->db_preserve_hmask) << 32;
*p_db = db;
}
ph->xops->xfer_put(ph, t);
dev_dbg(ph->dev,
"Using valid FC for protocol %X [MSG_ID:%u / RES_ID:%u]\n",
pi->proto->id, message_id, domain);
return;
err_db_mem:
devm_kfree(ph->dev, db);
err_db:
*p_addr = NULL;
err_xfer:
ph->xops->xfer_put(ph, t);
err_out:
dev_warn(ph->dev,
"Failed to get FC for protocol %X [MSG_ID:%u / RES_ID:%u] - ret:%d. Using regular messaging.\n",
pi->proto->id, message_id, domain, ret);
}
#define SCMI_PROTO_FC_RING_DB(w) \
do { \
u##w val = 0; \
\
if (db->mask) \
val = ioread##w(db->addr) & db->mask; \
iowrite##w((u##w)db->set | val, db->addr); \
} while (0)
static void scmi_common_fastchannel_db_ring(struct scmi_fc_db_info *db)
{
if (!db || !db->addr)
return;
if (db->width == 1)
SCMI_PROTO_FC_RING_DB(8);
else if (db->width == 2)
SCMI_PROTO_FC_RING_DB(16);
else if (db->width == 4)
SCMI_PROTO_FC_RING_DB(32);
else /* db->width == 8 */
#ifdef CONFIG_64BIT
SCMI_PROTO_FC_RING_DB(64);
#else
{
u64 val = 0;
if (db->mask)
val = ioread64_hi_lo(db->addr) & db->mask;
iowrite64_hi_lo(db->set | val, db->addr);
}
#endif
}
static const struct scmi_proto_helpers_ops helpers_ops = {
.extended_name_get = scmi_common_extended_name_get,
.iter_response_init = scmi_iterator_init,
.iter_response_run = scmi_iterator_run,
.fastchannel_init = scmi_common_fastchannel_init,
.fastchannel_db_ring = scmi_common_fastchannel_db_ring,
};
/**
* scmi_revision_area_get - Retrieve version memory area.
*
* @ph: A reference to the protocol handle.
*
* A helper to grab the version memory area reference during SCMI Base protocol
* initialization.
*
* Return: A reference to the version memory area associated to the SCMI
* instance underlying this protocol handle.
*/
struct scmi_revision_info *
scmi_revision_area_get(const struct scmi_protocol_handle *ph)
{
const struct scmi_protocol_instance *pi = ph_to_pi(ph);
return pi->handle->version;
}
/**
* scmi_alloc_init_protocol_instance - Allocate and initialize a protocol
* instance descriptor.
* @info: The reference to the related SCMI instance.
* @proto: The protocol descriptor.
*
* Allocate a new protocol instance descriptor, using the provided @proto
* description, against the specified SCMI instance @info, and initialize it;
* all resources management is handled via a dedicated per-protocol devres
* group.
*
* Context: Assumes to be called with @protocols_mtx already acquired.
* Return: A reference to a freshly allocated and initialized protocol instance
* or ERR_PTR on failure. On failure the @proto reference is at first
* put using @scmi_protocol_put() before releasing all the devres group.
*/
static struct scmi_protocol_instance *
scmi_alloc_init_protocol_instance(struct scmi_info *info,
const struct scmi_protocol *proto)
{
int ret = -ENOMEM;
void *gid;
struct scmi_protocol_instance *pi;
const struct scmi_handle *handle = &info->handle;
/* Protocol specific devres group */
gid = devres_open_group(handle->dev, NULL, GFP_KERNEL);
if (!gid) {
scmi_protocol_put(proto->id);
goto out;
}
pi = devm_kzalloc(handle->dev, sizeof(*pi), GFP_KERNEL);
if (!pi)
goto clean;
pi->gid = gid;
pi->proto = proto;
pi->handle = handle;
pi->ph.dev = handle->dev;
pi->ph.xops = &xfer_ops;
pi->ph.hops = &helpers_ops;
pi->ph.set_priv = scmi_set_protocol_priv;
pi->ph.get_priv = scmi_get_protocol_priv;
refcount_set(&pi->users, 1);
/* proto->init is assured NON NULL by scmi_protocol_register */
ret = pi->proto->instance_init(&pi->ph);
if (ret)
goto clean;
ret = idr_alloc(&info->protocols, pi, proto->id, proto->id + 1,
GFP_KERNEL);
if (ret != proto->id)
goto clean;
/*
* Warn but ignore events registration errors since we do not want
* to skip whole protocols if their notifications are messed up.
*/
if (pi->proto->events) {
ret = scmi_register_protocol_events(handle, pi->proto->id,
&pi->ph,
pi->proto->events);
if (ret)
dev_warn(handle->dev,
"Protocol:%X - Events Registration Failed - err:%d\n",
pi->proto->id, ret);
}
devres_close_group(handle->dev, pi->gid);
dev_dbg(handle->dev, "Initialized protocol: 0x%X\n", pi->proto->id);
if (pi->version > proto->supported_version)
dev_warn(handle->dev,
"Detected UNSUPPORTED higher version 0x%X for protocol 0x%X."
"Backward compatibility is NOT assured.\n",
pi->version, pi->proto->id);
return pi;
clean:
/* Take care to put the protocol module's owner before releasing all */
scmi_protocol_put(proto->id);
devres_release_group(handle->dev, gid);
out:
return ERR_PTR(ret);
}
/**
* scmi_get_protocol_instance - Protocol initialization helper.
* @handle: A reference to the SCMI platform instance.
* @protocol_id: The protocol being requested.
*
* In case the required protocol has never been requested before for this
* instance, allocate and initialize all the needed structures while handling
* resource allocation with a dedicated per-protocol devres subgroup.
*
* Return: A reference to an initialized protocol instance or error on failure:
* in particular returns -EPROBE_DEFER when the desired protocol could
* NOT be found.
*/
static struct scmi_protocol_instance * __must_check
scmi_get_protocol_instance(const struct scmi_handle *handle, u8 protocol_id)
{
struct scmi_protocol_instance *pi;
struct scmi_info *info = handle_to_scmi_info(handle);
mutex_lock(&info->protocols_mtx);
pi = idr_find(&info->protocols, protocol_id);
if (pi) {
refcount_inc(&pi->users);
} else {
const struct scmi_protocol *proto;
/* Fails if protocol not registered on bus */
proto = scmi_protocol_get(protocol_id);
if (proto)
pi = scmi_alloc_init_protocol_instance(info, proto);
else
pi = ERR_PTR(-EPROBE_DEFER);
}
mutex_unlock(&info->protocols_mtx);
return pi;
}
/**
* scmi_protocol_acquire - Protocol acquire
* @handle: A reference to the SCMI platform instance.
* @protocol_id: The protocol being requested.
*
* Register a new user for the requested protocol on the specified SCMI
* platform instance, possibly triggering its initialization on first user.
*
* Return: 0 if protocol was acquired successfully.
*/
int scmi_protocol_acquire(const struct scmi_handle *handle, u8 protocol_id)
{
return PTR_ERR_OR_ZERO(scmi_get_protocol_instance(handle, protocol_id));
}
/**
* scmi_protocol_release - Protocol de-initialization helper.
* @handle: A reference to the SCMI platform instance.
* @protocol_id: The protocol being requested.
*
* Remove one user for the specified protocol and triggers de-initialization
* and resources de-allocation once the last user has gone.
*/
void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id)
{
struct scmi_info *info = handle_to_scmi_info(handle);
struct scmi_protocol_instance *pi;
mutex_lock(&info->protocols_mtx);
pi = idr_find(&info->protocols, protocol_id);
if (WARN_ON(!pi))
goto out;
if (refcount_dec_and_test(&pi->users)) {
void *gid = pi->gid;
if (pi->proto->events)
scmi_deregister_protocol_events(handle, protocol_id);
if (pi->proto->instance_deinit)
pi->proto->instance_deinit(&pi->ph);
idr_remove(&info->protocols, protocol_id);
scmi_protocol_put(protocol_id);
devres_release_group(handle->dev, gid);
dev_dbg(handle->dev, "De-Initialized protocol: 0x%X\n",
protocol_id);
}
out:
mutex_unlock(&info->protocols_mtx);
}
void scmi_setup_protocol_implemented(const struct scmi_protocol_handle *ph,
u8 *prot_imp)
{
const struct scmi_protocol_instance *pi = ph_to_pi(ph);
struct scmi_info *info = handle_to_scmi_info(pi->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);
struct scmi_revision_info *rev = handle->version;
if (!info->protocols_imp)
return false;
for (i = 0; i < rev->num_protocols; i++)
if (info->protocols_imp[i] == prot_id)
return true;
return false;
}
struct scmi_protocol_devres {
const struct scmi_handle *handle;
u8 protocol_id;
};
static void scmi_devm_release_protocol(struct device *dev, void *res)
{
struct scmi_protocol_devres *dres = res;
scmi_protocol_release(dres->handle, dres->protocol_id);
}
static struct scmi_protocol_instance __must_check *
scmi_devres_protocol_instance_get(struct scmi_device *sdev, u8 protocol_id)
{
struct scmi_protocol_instance *pi;
struct scmi_protocol_devres *dres;
dres = devres_alloc(scmi_devm_release_protocol,
sizeof(*dres), GFP_KERNEL);
if (!dres)
return ERR_PTR(-ENOMEM);
pi = scmi_get_protocol_instance(sdev->handle, protocol_id);
if (IS_ERR(pi)) {
devres_free(dres);
return pi;
}
dres->handle = sdev->handle;
dres->protocol_id = protocol_id;
devres_add(&sdev->dev, dres);
return pi;
}
/**
* scmi_devm_protocol_get - Devres managed get protocol operations and handle
* @sdev: A reference to an scmi_device whose embedded struct device is to
* be used for devres accounting.
* @protocol_id: The protocol being requested.
* @ph: A pointer reference used to pass back the associated protocol handle.
*
* Get hold of a protocol accounting for its usage, eventually triggering its
* initialization, and returning the protocol specific operations and related
* protocol handle which will be used as first argument in most of the
* protocols operations methods.
* Being a devres based managed method, protocol hold will be automatically
* released, and possibly de-initialized on last user, once the SCMI driver
* owning the scmi_device is unbound from it.
*
* Return: A reference to the requested protocol operations or error.
* Must be checked for errors by caller.
*/
static const void __must_check *
scmi_devm_protocol_get(struct scmi_device *sdev, u8 protocol_id,
struct scmi_protocol_handle **ph)
{
struct scmi_protocol_instance *pi;
if (!ph)
return ERR_PTR(-EINVAL);
pi = scmi_devres_protocol_instance_get(sdev, protocol_id);
if (IS_ERR(pi))
return pi;
*ph = &pi->ph;
return pi->proto->ops;
}
/**
* scmi_devm_protocol_acquire - Devres managed helper to get hold of a protocol
* @sdev: A reference to an scmi_device whose embedded struct device is to
* be used for devres accounting.
* @protocol_id: The protocol being requested.
*
* Get hold of a protocol accounting for its usage, possibly triggering its
* initialization but without getting access to its protocol specific operations
* and handle.
*
* Being a devres based managed method, protocol hold will be automatically
* released, and possibly de-initialized on last user, once the SCMI driver
* owning the scmi_device is unbound from it.
*
* Return: 0 on SUCCESS
*/
static int __must_check scmi_devm_protocol_acquire(struct scmi_device *sdev,
u8 protocol_id)
{
struct scmi_protocol_instance *pi;
pi = scmi_devres_protocol_instance_get(sdev, protocol_id);
if (IS_ERR(pi))
return PTR_ERR(pi);
return 0;
}
static int scmi_devm_protocol_match(struct device *dev, void *res, void *data)
{
struct scmi_protocol_devres *dres = res;
if (WARN_ON(!dres || !data))
return 0;
return dres->protocol_id == *((u8 *)data);
}
/**
* scmi_devm_protocol_put - Devres managed put protocol operations and handle
* @sdev: A reference to an scmi_device whose embedded struct device is to
* be used for devres accounting.
* @protocol_id: The protocol being requested.
*
* Explicitly release a protocol hold previously obtained calling the above
* @scmi_devm_protocol_get.
*/
static void scmi_devm_protocol_put(struct scmi_device *sdev, u8 protocol_id)
{
int ret;
ret = devres_release(&sdev->dev, scmi_devm_release_protocol,
scmi_devm_protocol_match, &protocol_id);
WARN_ON(ret);
}
/**
* scmi_is_transport_atomic - Method to check if underlying transport for an
* SCMI instance is configured as atomic.
*
* @handle: A reference to the SCMI platform instance.
* @atomic_threshold: An optional return value for the system wide currently
* configured threshold for atomic operations.
*
* Return: True if transport is configured as atomic
*/
static bool scmi_is_transport_atomic(const struct scmi_handle *handle,
unsigned int *atomic_threshold)
{
bool ret;
struct scmi_info *info = handle_to_scmi_info(handle);
ret = info->desc->atomic_enabled &&
is_transport_polling_capable(info->desc);
if (ret && atomic_threshold)
*atomic_threshold = info->atomic_threshold;
return ret;
}
/**
* 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
*/
static 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) {
info->users++;
handle = &info->handle;
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;
*/
static 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 void scmi_device_link_add(struct device *consumer,
struct device *supplier)
{
struct device_link *link;
link = device_link_add(consumer, supplier, DL_FLAG_AUTOREMOVE_CONSUMER);
WARN_ON(!link);
}
static void scmi_set_handle(struct scmi_device *scmi_dev)
{
scmi_dev->handle = scmi_handle_get(&scmi_dev->dev);
if (scmi_dev->handle)
scmi_device_link_add(&scmi_dev->dev, scmi_dev->handle->dev);
}
static int __scmi_xfer_info_init(struct scmi_info *sinfo,
struct scmi_xfers_info *info)
{
int i;
struct scmi_xfer *xfer;
struct device *dev = sinfo->dev;
const struct scmi_desc *desc = sinfo->desc;
/* Pre-allocated messages, no more than what hdr.seq can support */
if (WARN_ON(!info->max_msg || info->max_msg > MSG_TOKEN_MAX)) {
dev_err(dev,
"Invalid maximum messages %d, not in range [1 - %lu]\n",
info->max_msg, MSG_TOKEN_MAX);
return -EINVAL;
}
hash_init(info->pending_xfers);
/* Allocate a bitmask sized to hold MSG_TOKEN_MAX tokens */
info->xfer_alloc_table = devm_bitmap_zalloc(dev, MSG_TOKEN_MAX,
GFP_KERNEL);
if (!info->xfer_alloc_table)
return -ENOMEM;
/*
* Preallocate a number of xfers equal to max inflight messages,
* pre-initialize the buffer pointer to pre-allocated buffers and
* attach all of them to the free list
*/
INIT_HLIST_HEAD(&info->free_xfers);
for (i = 0; i < info->max_msg; i++) {
xfer = devm_kzalloc(dev, sizeof(*xfer), GFP_KERNEL);
if (!xfer)
return -ENOMEM;
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(&xfer->lock);
/* Add initialized xfer to the free list */
hlist_add_head(&xfer->node, &info->free_xfers);
}
spin_lock_init(&info->xfer_lock);
return 0;
}
static int scmi_channels_max_msg_configure(struct scmi_info *sinfo)
{
const struct scmi_desc *desc = sinfo->desc;
if (!desc->ops->get_max_msg) {
sinfo->tx_minfo.max_msg = desc->max_msg;
sinfo->rx_minfo.max_msg = desc->max_msg;
} else {
struct scmi_chan_info *base_cinfo;
base_cinfo = idr_find(&sinfo->tx_idr, SCMI_PROTOCOL_BASE);
if (!base_cinfo)
return -EINVAL;
sinfo->tx_minfo.max_msg = desc->ops->get_max_msg(base_cinfo);
/* RX channel is optional so can be skipped */
base_cinfo = idr_find(&sinfo->rx_idr, SCMI_PROTOCOL_BASE);
if (base_cinfo)
sinfo->rx_minfo.max_msg =
desc->ops->get_max_msg(base_cinfo);
}
return 0;
}
static int scmi_xfer_info_init(struct scmi_info *sinfo)
{
int ret;
ret = scmi_channels_max_msg_configure(sinfo);
if (ret)
return ret;
ret = __scmi_xfer_info_init(sinfo, &sinfo->tx_minfo);
if (!ret && !idr_is_empty(&sinfo->rx_idr))
ret = __scmi_xfer_info_init(sinfo, &sinfo->rx_minfo);
return ret;
}
static int scmi_chan_setup(struct scmi_info *info, struct device_node *of_node,
int prot_id, bool tx)
{
int ret, idx;
char name[32];
struct scmi_chan_info *cinfo;
struct idr *idr;
struct scmi_device *tdev = NULL;
/* Transmit channel is first entry i.e. index 0 */
idx = tx ? 0 : 1;
idr = tx ? &info->tx_idr : &info->rx_idr;
if (!info->desc->ops->chan_available(of_node, 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->rx_timeout_ms = info->desc->max_rx_timeout_ms;
/* Create a unique name for this transport device */
snprintf(name, 32, "__scmi_transport_device_%s_%02X",
idx ? "rx" : "tx", prot_id);
/* Create a uniquely named, dedicated transport device for this chan */
tdev = scmi_device_create(of_node, info->dev, prot_id, name);
if (!tdev) {
dev_err(info->dev,
"failed to create transport device (%s)\n", name);
devm_kfree(info->dev, cinfo);
return -EINVAL;
}
of_node_get(of_node);
cinfo->id = prot_id;
cinfo->dev = &tdev->dev;
ret = info->desc->ops->chan_setup(cinfo, info->dev, tx);
if (ret) {
of_node_put(of_node);
scmi_device_destroy(info->dev, prot_id, name);
devm_kfree(info->dev, cinfo);
return ret;
}
if (tx && is_polling_required(cinfo, info->desc)) {
if (is_transport_polling_capable(info->desc))
dev_info(&tdev->dev,
"Enabled polling mode TX channel - prot_id:%d\n",
prot_id);
else
dev_warn(&tdev->dev,
"Polling mode NOT supported by transport.\n");
}
idr_alloc:
ret = idr_alloc(idr, cinfo, prot_id, prot_id + 1, GFP_KERNEL);
if (ret != prot_id) {
dev_err(info->dev,
"unable to allocate SCMI idr slot err %d\n", ret);
/* Destroy channel and device only if created by this call. */
if (tdev) {
of_node_put(of_node);
scmi_device_destroy(info->dev, prot_id, name);
devm_kfree(info->dev, cinfo);
}
return ret;
}
cinfo->handle = &info->handle;
return 0;
}
static inline int
scmi_txrx_setup(struct scmi_info *info, struct device_node *of_node,
int prot_id)
{
int ret = scmi_chan_setup(info, of_node, prot_id, true);
if (!ret) {
/* Rx is optional, report only memory errors */
ret = scmi_chan_setup(info, of_node, prot_id, false);
if (ret && ret != -ENOMEM)
ret = 0;
}
return ret;
}
/**
* scmi_channels_setup - Helper to initialize all required channels
*
* @info: The SCMI instance descriptor.
*
* Initialize all the channels found described in the DT against the underlying
* configured transport using custom defined dedicated devices instead of
* borrowing devices from the SCMI drivers; this way channels are initialized
* upfront during core SCMI stack probing and are no more coupled with SCMI
* devices used by SCMI drivers.
*
* Note that, even though a pair of TX/RX channels is associated to each
* protocol defined in the DT, a distinct freshly initialized channel is
* created only if the DT node for the protocol at hand describes a dedicated
* channel: in all the other cases the common BASE protocol channel is reused.
*
* Return: 0 on Success
*/
static int scmi_channels_setup(struct scmi_info *info)
{
int ret;
struct device_node *child, *top_np = info->dev->of_node;
/* Initialize a common generic channel at first */
ret = scmi_txrx_setup(info, top_np, SCMI_PROTOCOL_BASE);
if (ret)
return ret;
for_each_available_child_of_node(top_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(info->dev,
"Out of range protocol %d\n", prot_id);
ret = scmi_txrx_setup(info, child, prot_id);
if (ret) {
of_node_put(child);
return ret;
}
}
return 0;
}
static int scmi_chan_destroy(int id, void *p, void *idr)
{
struct scmi_chan_info *cinfo = p;
if (cinfo->dev) {
struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
struct scmi_device *sdev = to_scmi_dev(cinfo->dev);
of_node_put(cinfo->dev->of_node);
scmi_device_destroy(info->dev, id, sdev->name);
cinfo->dev = NULL;
}
idr_remove(idr, id);
return 0;
}
static void scmi_cleanup_channels(struct scmi_info *info, struct idr *idr)
{
/* At first free all channels at the transport layer ... */
idr_for_each(idr, info->desc->ops->chan_free, idr);
/* ...then destroy all underlying devices */
idr_for_each(idr, scmi_chan_destroy, idr);
idr_destroy(idr);
}
static void scmi_cleanup_txrx_channels(struct scmi_info *info)
{
scmi_cleanup_channels(info, &info->tx_idr);
scmi_cleanup_channels(info, &info->rx_idr);
}
static int scmi_bus_notifier(struct notifier_block *nb,
unsigned long action, void *data)
{
struct scmi_info *info = bus_nb_to_scmi_info(nb);
struct scmi_device *sdev = to_scmi_dev(data);
/* Skip transport devices and devices of different SCMI instances */
if (!strncmp(sdev->name, "__scmi_transport_device", 23) ||
sdev->dev.parent != info->dev)
return NOTIFY_DONE;
switch (action) {
case BUS_NOTIFY_BIND_DRIVER:
/* setup handle now as the transport is ready */
scmi_set_handle(sdev);
break;
case BUS_NOTIFY_UNBOUND_DRIVER:
scmi_handle_put(sdev->handle);
sdev->handle = NULL;
break;
default:
return NOTIFY_DONE;
}
dev_dbg(info->dev, "Device %s (%s) is now %s\n", dev_name(&sdev->dev),
sdev->name, action == BUS_NOTIFY_BIND_DRIVER ?
"about to be BOUND." : "UNBOUND.");
return NOTIFY_OK;
}
static int scmi_device_request_notifier(struct notifier_block *nb,
unsigned long action, void *data)
{
struct device_node *np;
struct scmi_device_id *id_table = data;
struct scmi_info *info = req_nb_to_scmi_info(nb);
np = idr_find(&info->active_protocols, id_table->protocol_id);
if (!np)
return NOTIFY_DONE;
dev_dbg(info->dev, "%sRequested device (%s) for protocol 0x%x\n",
action == SCMI_BUS_NOTIFY_DEVICE_REQUEST ? "" : "UN-",
id_table->name, id_table->protocol_id);
switch (action) {
case SCMI_BUS_NOTIFY_DEVICE_REQUEST:
scmi_create_protocol_devices(np, info, id_table->protocol_id,
id_table->name);
break;
case SCMI_BUS_NOTIFY_DEVICE_UNREQUEST:
scmi_destroy_protocol_devices(info, id_table->protocol_id,
id_table->name);
break;
default:
return NOTIFY_DONE;
}
return NOTIFY_OK;
}
static void scmi_debugfs_common_cleanup(void *d)
{
struct scmi_debug_info *dbg = d;
if (!dbg)
return;
debugfs_remove_recursive(dbg->top_dentry);
kfree(dbg->name);
kfree(dbg->type);
}
static struct scmi_debug_info *scmi_debugfs_common_setup(struct scmi_info *info)
{
char top_dir[16];
struct dentry *trans, *top_dentry;
struct scmi_debug_info *dbg;
const char *c_ptr = NULL;
dbg = devm_kzalloc(info->dev, sizeof(*dbg), GFP_KERNEL);
if (!dbg)
return NULL;
dbg->name = kstrdup(of_node_full_name(info->dev->of_node), GFP_KERNEL);
if (!dbg->name) {
devm_kfree(info->dev, dbg);
return NULL;
}
of_property_read_string(info->dev->of_node, "compatible", &c_ptr);
dbg->type = kstrdup(c_ptr, GFP_KERNEL);
if (!dbg->type) {
kfree(dbg->name);
devm_kfree(info->dev, dbg);
return NULL;
}
snprintf(top_dir, 16, "%d", info->id);
top_dentry = debugfs_create_dir(top_dir, scmi_top_dentry);
trans = debugfs_create_dir("transport", top_dentry);
dbg->is_atomic = info->desc->atomic_enabled &&
is_transport_polling_capable(info->desc);
debugfs_create_str("instance_name", 0400, top_dentry,
(char **)&dbg->name);
debugfs_create_u32("atomic_threshold_us", 0400, top_dentry,
&info->atomic_threshold);
debugfs_create_str("type", 0400, trans, (char **)&dbg->type);
debugfs_create_bool("is_atomic", 0400, trans, &dbg->is_atomic);
debugfs_create_u32("max_rx_timeout_ms", 0400, trans,
(u32 *)&info->desc->max_rx_timeout_ms);
debugfs_create_u32("max_msg_size", 0400, trans,
(u32 *)&info->desc->max_msg_size);
debugfs_create_u32("tx_max_msg", 0400, trans,
(u32 *)&info->tx_minfo.max_msg);
debugfs_create_u32("rx_max_msg", 0400, trans,
(u32 *)&info->rx_minfo.max_msg);
dbg->top_dentry = top_dentry;
if (devm_add_action_or_reset(info->dev,
scmi_debugfs_common_cleanup, dbg)) {
scmi_debugfs_common_cleanup(dbg);
return NULL;
}
return dbg;
}
static int scmi_debugfs_raw_mode_setup(struct scmi_info *info)
{
int id, num_chans = 0, ret = 0;
struct scmi_chan_info *cinfo;
u8 channels[SCMI_MAX_CHANNELS] = {};
DECLARE_BITMAP(protos, SCMI_MAX_CHANNELS) = {};
if (!info->dbg)
return -EINVAL;
/* Enumerate all channels to collect their ids */
idr_for_each_entry(&info->tx_idr, cinfo, id) {
/*
* Cannot happen, but be defensive.
* Zero as num_chans is ok, warn and carry on.
*/
if (num_chans >= SCMI_MAX_CHANNELS || !cinfo) {
dev_warn(info->dev,
"SCMI RAW - Error enumerating channels\n");
break;
}
if (!test_bit(cinfo->id, protos)) {
channels[num_chans++] = cinfo->id;
set_bit(cinfo->id, protos);
}
}
info->raw = scmi_raw_mode_init(&info->handle, info->dbg->top_dentry,
info->id, channels, num_chans,
info->desc, info->tx_minfo.max_msg);
if (IS_ERR(info->raw)) {
dev_err(info->dev, "Failed to initialize SCMI RAW Mode !\n");
ret = PTR_ERR(info->raw);
info->raw = NULL;
}
return ret;
}
static int scmi_probe(struct platform_device *pdev)
{
int ret;
struct scmi_handle *handle;
const struct scmi_desc *desc;
struct scmi_info *info;
bool coex = IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT_COEX);
struct device *dev = &pdev->dev;
struct device_node *child, *np = dev->of_node;
desc = of_device_get_match_data(dev);
if (!desc)
return -EINVAL;
info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
if (!info)
return -ENOMEM;
info->id = ida_alloc_min(&scmi_id, 0, GFP_KERNEL);
if (info->id < 0)
return info->id;
info->dev = dev;
info->desc = desc;
info->bus_nb.notifier_call = scmi_bus_notifier;
info->dev_req_nb.notifier_call = scmi_device_request_notifier;
INIT_LIST_HEAD(&info->node);
idr_init(&info->protocols);
mutex_init(&info->protocols_mtx);
idr_init(&info->active_protocols);
mutex_init(&info->devreq_mtx);
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;
handle->devm_protocol_acquire = scmi_devm_protocol_acquire;
handle->devm_protocol_get = scmi_devm_protocol_get;
handle->devm_protocol_put = scmi_devm_protocol_put;
/* System wide atomic threshold for atomic ops .. if any */
if (!of_property_read_u32(np, "atomic-threshold-us",
&info->atomic_threshold))
dev_info(dev,
"SCMI System wide atomic threshold set to %d us\n",
info->atomic_threshold);
handle->is_transport_atomic = scmi_is_transport_atomic;
if (desc->ops->link_supplier) {
ret = desc->ops->link_supplier(dev);
if (ret)
goto clear_ida;
}
/* Setup all channels described in the DT at first */
ret = scmi_channels_setup(info);
if (ret)
goto clear_ida;
ret = bus_register_notifier(&scmi_bus_type, &info->bus_nb);
if (ret)
goto clear_txrx_setup;
ret = blocking_notifier_chain_register(&scmi_requested_devices_nh,
&info->dev_req_nb);
if (ret)
goto clear_bus_notifier;
ret = scmi_xfer_info_init(info);
if (ret)
goto clear_dev_req_notifier;
if (scmi_top_dentry) {
info->dbg = scmi_debugfs_common_setup(info);
if (!info->dbg)
dev_warn(dev, "Failed to setup SCMI debugfs.\n");
if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
ret = scmi_debugfs_raw_mode_setup(info);
if (!coex) {
if (ret)
goto clear_dev_req_notifier;
/* Bail out anyway when coex disabled. */
return 0;
}
/* Coex enabled, carry on in any case. */
dev_info(dev, "SCMI RAW Mode COEX enabled !\n");
}
}
if (scmi_notification_init(handle))
dev_err(dev, "SCMI Notifications NOT available.\n");
if (info->desc->atomic_enabled &&
!is_transport_polling_capable(info->desc))
dev_err(dev,
"Transport is not polling capable. Atomic mode not supported.\n");
/*
* Trigger SCMI Base protocol initialization.
* It's mandatory and won't be ever released/deinit until the
* SCMI stack is shutdown/unloaded as a whole.
*/
ret = scmi_protocol_acquire(handle, SCMI_PROTOCOL_BASE);
if (ret) {
dev_err(dev, "unable to communicate with SCMI\n");
if (coex)
return 0;
goto notification_exit;
}
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;
}
/*
* Save this valid DT protocol descriptor amongst
* @active_protocols for this SCMI instance/
*/
ret = idr_alloc(&info->active_protocols, child,
prot_id, prot_id + 1, GFP_KERNEL);
if (ret != prot_id) {
dev_err(dev, "SCMI protocol %d already activated. Skip\n",
prot_id);
continue;
}
of_node_get(child);
scmi_create_protocol_devices(child, info, prot_id, NULL);
}
return 0;
notification_exit:
if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT))
scmi_raw_mode_cleanup(info->raw);
scmi_notification_exit(&info->handle);
clear_dev_req_notifier:
blocking_notifier_chain_unregister(&scmi_requested_devices_nh,
&info->dev_req_nb);
clear_bus_notifier:
bus_unregister_notifier(&scmi_bus_type, &info->bus_nb);
clear_txrx_setup:
scmi_cleanup_txrx_channels(info);
clear_ida:
ida_free(&scmi_id, info->id);
return ret;
}
static void scmi_remove(struct platform_device *pdev)
{
int id;
struct scmi_info *info = platform_get_drvdata(pdev);
struct device_node *child;
if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT))
scmi_raw_mode_cleanup(info->raw);
mutex_lock(&scmi_list_mutex);
if (info->users)
dev_warn(&pdev->dev,
"Still active SCMI users will be forcibly unbound.\n");
list_del(&info->node);
mutex_unlock(&scmi_list_mutex);
scmi_notification_exit(&info->handle);
mutex_lock(&info->protocols_mtx);
idr_destroy(&info->protocols);
mutex_unlock(&info->protocols_mtx);
idr_for_each_entry(&info->active_protocols, child, id)
of_node_put(child);
idr_destroy(&info->active_protocols);
blocking_notifier_chain_unregister(&scmi_requested_devices_nh,
&info->dev_req_nb);
bus_unregister_notifier(&scmi_bus_type, &info->bus_nb);
/* Safe to free channels since no more users */
scmi_cleanup_txrx_channels(info);
ida_free(&scmi_id, info->id);
}
static ssize_t protocol_version_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct scmi_info *info = dev_get_drvdata(dev);
return sprintf(buf, "%u.%u\n", info->version.major_ver,
info->version.minor_ver);
}
static DEVICE_ATTR_RO(protocol_version);
static ssize_t firmware_version_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct scmi_info *info = dev_get_drvdata(dev);
return sprintf(buf, "0x%x\n", info->version.impl_ver);
}
static DEVICE_ATTR_RO(firmware_version);
static ssize_t vendor_id_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct scmi_info *info = dev_get_drvdata(dev);
return sprintf(buf, "%s\n", info->version.vendor_id);
}
static DEVICE_ATTR_RO(vendor_id);
static ssize_t sub_vendor_id_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct scmi_info *info = dev_get_drvdata(dev);
return sprintf(buf, "%s\n", info->version.sub_vendor_id);
}
static DEVICE_ATTR_RO(sub_vendor_id);
static struct attribute *versions_attrs[] = {
&dev_attr_firmware_version.attr,
&dev_attr_protocol_version.attr,
&dev_attr_vendor_id.attr,
&dev_attr_sub_vendor_id.attr,
NULL,
};
ATTRIBUTE_GROUPS(versions);
/* Each compatible listed below must have descriptor associated with it */
static const struct of_device_id scmi_of_match[] = {
#ifdef CONFIG_ARM_SCMI_TRANSPORT_MAILBOX
{ .compatible = "arm,scmi", .data = &scmi_mailbox_desc },
#endif
#ifdef CONFIG_ARM_SCMI_TRANSPORT_OPTEE
{ .compatible = "linaro,scmi-optee", .data = &scmi_optee_desc },
#endif
#ifdef CONFIG_ARM_SCMI_TRANSPORT_SMC
{ .compatible = "arm,scmi-smc", .data = &scmi_smc_desc},
{ .compatible = "arm,scmi-smc-param", .data = &scmi_smc_desc},
{ .compatible = "qcom,scmi-smc", .data = &scmi_smc_desc},
#endif
#ifdef CONFIG_ARM_SCMI_TRANSPORT_VIRTIO
{ .compatible = "arm,scmi-virtio", .data = &scmi_virtio_desc},
#endif
{ /* Sentinel */ },
};
MODULE_DEVICE_TABLE(of, scmi_of_match);
static struct platform_driver scmi_driver = {
.driver = {
.name = "arm-scmi",
.suppress_bind_attrs = true,
.of_match_table = scmi_of_match,
.dev_groups = versions_groups,
},
.probe = scmi_probe,
.remove_new = scmi_remove,
};
/**
* __scmi_transports_setup - Common helper to call transport-specific
* .init/.exit code if provided.
*
* @init: A flag to distinguish between init and exit.
*
* Note that, if provided, we invoke .init/.exit functions for all the
* transports currently compiled in.
*
* Return: 0 on Success.
*/
static inline int __scmi_transports_setup(bool init)
{
int ret = 0;
const struct of_device_id *trans;
for (trans = scmi_of_match; trans->data; trans++) {
const struct scmi_desc *tdesc = trans->data;
if ((init && !tdesc->transport_init) ||
(!init && !tdesc->transport_exit))
continue;
if (init)
ret = tdesc->transport_init();
else
tdesc->transport_exit();
if (ret) {
pr_err("SCMI transport %s FAILED initialization!\n",
trans->compatible);
break;
}
}
return ret;
}
static int __init scmi_transports_init(void)
{
return __scmi_transports_setup(true);
}
static void __exit scmi_transports_exit(void)
{
__scmi_transports_setup(false);
}
static struct dentry *scmi_debugfs_init(void)
{
struct dentry *d;
d = debugfs_create_dir("scmi", NULL);
if (IS_ERR(d)) {
pr_err("Could NOT create SCMI top dentry.\n");
return NULL;
}
return d;
}
static int __init scmi_driver_init(void)
{
int ret;
/* Bail out if no SCMI transport was configured */
if (WARN_ON(!IS_ENABLED(CONFIG_ARM_SCMI_HAVE_TRANSPORT)))
return -EINVAL;
/* Initialize any compiled-in transport which provided an init/exit */
ret = scmi_transports_init();
if (ret)
return ret;
if (IS_ENABLED(CONFIG_ARM_SCMI_NEED_DEBUGFS))
scmi_top_dentry = scmi_debugfs_init();
scmi_base_register();
scmi_clock_register();
scmi_perf_register();
scmi_power_register();
scmi_reset_register();
scmi_sensors_register();
scmi_voltage_register();
scmi_system_register();
scmi_powercap_register();
return platform_driver_register(&scmi_driver);
}
module_init(scmi_driver_init);
static void __exit scmi_driver_exit(void)
{
scmi_base_unregister();
scmi_clock_unregister();
scmi_perf_unregister();
scmi_power_unregister();
scmi_reset_unregister();
scmi_sensors_unregister();
scmi_voltage_unregister();
scmi_system_unregister();
scmi_powercap_unregister();
scmi_transports_exit();
platform_driver_unregister(&scmi_driver);
debugfs_remove_recursive(scmi_top_dentry);
}
module_exit(scmi_driver_exit);
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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