diff options
Diffstat (limited to 'drivers/firmware/arm_scmi/driver.c')
| -rw-r--r-- | drivers/firmware/arm_scmi/driver.c | 1767 |
1 files changed, 1767 insertions, 0 deletions
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c new file mode 100644 index 0000000000..e602f7a440 --- /dev/null +++ b/drivers/firmware/arm_scmi/driver.c @@ -0,0 +1,1767 @@ +// 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 <common.h> +#include <linux/bitmap.h> +#include <driver.h> +#include <linux/export.h> +#include <linux/notifier.h> +#include <linux/io.h> +#include <io-64-nonatomic-hi-lo.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <of_address.h> +#include <of_device.h> +#include <linux/slab.h> +#include <linux/idr.h> +#include <linux/mutex.h> +#include <linux/processor.h> + +#include "common.h" + +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; + +/** + * 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. + */ +struct scmi_xfers_info { + unsigned long *xfer_alloc_table; + spinlock_t xfer_lock; + int max_msg; + struct hlist_head free_xfers; +}; + +/** + * 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. + * @users: A refcount to track effective users of this protocol. + * @priv: Reference for optional protocol private data. + * @ph: An embedded protocol handle that will be passed down to protocol + * initialization code to identify this instance. + * + * Each protocol is initialized independently once for each SCMI platform in + * which is defined by DT and implemented by the SCMI server fw. + */ +struct scmi_protocol_instance { + const struct scmi_handle *handle; + const struct scmi_protocol *proto; + refcount_t users; + void *priv; + struct scmi_protocol_handle ph; +}; + +#define ph_to_pi(h) container_of(h, struct scmi_protocol_instance, ph) + +/** + * struct scmi_info - Structure representing a SCMI instance + * + * @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. + * @node: List head + * @users: Number of users of this instance + * @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 + */ +struct scmi_info { + struct device *dev; + const struct scmi_desc *desc; + struct scmi_revision_info version; + struct scmi_handle handle; + struct scmi_xfers_info tx_minfo; + struct scmi_xfers_info rx_minfo; + struct idr tx_idr; + struct idr rx_idr; + struct idr protocols; + /* Ensure mutual exclusive access to protocols instance array */ + struct mutex protocols_mtx; + u8 *protocols_imp; + struct idr active_protocols; + unsigned int atomic_threshold; + struct list_head node; + struct notifier_block dev_req_nb; + /* Serialize device creation process for this instance */ + struct mutex devreq_mtx; +}; + +#define handle_to_scmi_info(h) container_of(h, struct scmi_info, handle) +#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) { + 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; +} + +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_one(&scmi_protocols, (void *)proto, proto->id); + 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); + +/** + * 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); +} + +/** + * 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); + xfer->pending = true; +} + +/** + * 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_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); + xfer->pending = false; + } + hlist_add_head(&xfer->node, &minfo->free_xfers); + } + spin_unlock_irqrestore(&minfo->xfer_lock, flags); +} + +/** + * 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 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; + unsigned long flags; + + /* + * Do not fetch_response if an out-of-order delayed + * response is being processed. + */ + spin_lock_irqsave(&xfer->lock, flags); + if (xfer->state == SCMI_XFER_SENT_OK) { + desc->ops->fetch_response(cinfo, xfer); + xfer->state = SCMI_XFER_RESP_OK; + } + spin_unlock_irqrestore(&xfer->lock, flags); + + 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. + * + * 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; + + return scmi_wait_for_reply(dev, info->desc, cinfo, xfer, + info->desc->max_rx_timeout_ms); +} + +/** + * 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 (!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; + + /* + * 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; + + /* Clear any stale status */ + xfer->hdr.status = SCMI_SUCCESS; + xfer->state = SCMI_XFER_SENT_OK; + + ret = info->desc->ops->send_message(cinfo, xfer); + if (ret < 0) { + dev_dbg(dev, "Failed to send message %d\n", ret); + return ret; + } + + 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); + + 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; +} + +/** + * 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; + + *p = xfer; + + return 0; +} + +/** + * version_get() - command to get the revision of the SCMI entity + * + * @ph: Pointer to SCMI protocol handle + * @version: Holds returned version of protocol. + * + * Updates the SCMI information in the internal data structure. + * + * Return: 0 if all went fine, else return appropriate error. + */ +static int version_get(const struct scmi_protocol_handle *ph, u32 *version) +{ + int ret; + __le32 *rev_info; + struct scmi_xfer *t; + + ret = xfer_get_init(ph, PROTOCOL_VERSION, 0, sizeof(*version), &t); + if (ret) + return ret; + + ret = do_xfer(ph, t); + if (!ret) { + rev_info = t->rx.buf; + *version = le32_to_cpu(*rev_info); + } + + xfer_put(ph, t); + return ret; +} + +/** + * scmi_set_protocol_priv - Set protocol specific data at init time + * + * @ph: A reference to the protocol handle. + * @priv: The private data to set. + * + * Return: 0 on Success + */ +static int scmi_set_protocol_priv(const struct scmi_protocol_handle *ph, + void *priv) +{ + struct scmi_protocol_instance *pi = ph_to_pi(ph); + + pi->priv = priv; + + return 0; +} + +/** + * scmi_get_protocol_priv - Set protocol specific data at init time + * + * @ph: A reference to the protocol handle. + * + * Return: Protocol private data if any was set. + */ +static void *scmi_get_protocol_priv(const struct scmi_protocol_handle *ph) +{ + const struct scmi_protocol_instance *pi = ph_to_pi(ph); + + return pi->priv; +} + +static const struct scmi_xfer_ops xfer_ops = { + .version_get = version_get, + .xfer_get_init = xfer_get_init, + .reset_rx_to_maxsz = reset_rx_to_maxsz, + .do_xfer = do_xfer, + .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. + * @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, char *name, + size_t len) +{ + int ret; + struct scmi_xfer *t; + struct scmi_msg_resp_domain_name_get *resp; + + ret = ph->xops->xfer_get_init(ph, cmd_id, sizeof(res_id), + sizeof(*resp), &t); + if (ret) + goto out; + + put_unaligned_le32(res_id, t->tx.buf); + 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. + * + * 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. + */ +static struct scmi_protocol_instance * +scmi_alloc_init_protocol_instance(struct scmi_info *info, + const struct scmi_protocol *proto) +{ + int ret = -ENOMEM; + struct scmi_protocol_instance *pi; + const struct scmi_handle *handle = &info->handle; + + pi = devm_kzalloc(handle->dev, sizeof(*pi), GFP_KERNEL); + if (!pi) + goto clean; + + 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_one(&info->protocols, pi, proto->id); + if (ret != proto->id) + goto clean; + + dev_dbg(handle->dev, "Initialized protocol: 0x%X\n", pi->proto->id); + + return pi; + +clean: + 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. + * + * 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)) { + if (pi->proto->instance_deinit) + pi->proto->instance_deinit(&pi->ph); + + idr_remove(&info->protocols, protocol_id); + + 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; +} + +static const void __must_check * +scmi_dev_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_get_protocol_instance(sdev->handle, protocol_id); + if (IS_ERR(pi)) + return ERR_CAST(pi); + + *ph = &pi->ph; + + return pi->proto->ops; +} + +static int __must_check scmi_dev_protocol_acquire(struct scmi_device *sdev, + u8 protocol_id) +{ + return PTR_ERR_OR_ZERO(scmi_get_protocol_instance(sdev->handle, protocol_id)); +} + +static void scmi_dev_protocol_put(struct scmi_device *sdev, u8 protocol_id) +{ + scmi_protocol_release(sdev->handle, protocol_id); +} + +/** + * 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 = is_transport_polling_capable(info->desc); + if (ret && atomic_threshold) + *atomic_threshold = info->atomic_threshold; + + return ret; +} + +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; + } + + /* 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; + 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; +} + +/** + * scmi_handle_get() - Get the SCMI handle for a device + * + * @dev: pointer to device for which we want SCMI handle + * + * NOTE: The function does not track individual clients of the framework + * and is expected to be maintained by caller of SCMI protocol library. + * scmi_handle_put must be balanced with successful scmi_handle_get + * + * Return: pointer to handle if successful, NULL on error + */ +struct scmi_handle *scmi_handle_get(struct device *dev) +{ + struct list_head *p; + struct scmi_info *info; + struct scmi_handle *handle = NULL; + + mutex_lock(&scmi_list_mutex); + list_for_each(p, &scmi_list) { + info = list_entry(p, struct scmi_info, node); + if (dev->parent == info->dev) { + handle = &info->handle; + break; + } + } + mutex_unlock(&scmi_list_mutex); + + return handle; +} + +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_dbg(&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_one(idr, cinfo, prot_id); + 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_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 int scmi_probe(struct device *dev) +{ + int ret; + struct scmi_handle *handle; + const struct scmi_desc *desc; + struct scmi_info *info; + 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->dev = dev; + info->desc = desc; + 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); + + dev->priv = info; + idr_init(&info->tx_idr); + idr_init(&info->rx_idr); + + handle = &info->handle; + handle->dev = info->dev; + handle->version = &info->version; + handle->dev_protocol_acquire = scmi_dev_protocol_acquire; + handle->dev_protocol_get = scmi_dev_protocol_get; + handle->dev_protocol_put = scmi_dev_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 = blocking_notifier_chain_register(&scmi_requested_devices_nh, + &info->dev_req_nb); + if (ret) + goto clear_txrx_setup; + + ret = scmi_xfer_info_init(info); + if (ret) + goto clear_dev_req_notifier; + + if (!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. + */ + ret = scmi_protocol_acquire(handle, SCMI_PROTOCOL_BASE); + if (ret) { + dev_err(dev, "unable to communicate with SCMI\n"); + 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_one(&info->active_protocols, child, prot_id); + 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: +clear_dev_req_notifier: + blocking_notifier_chain_unregister(&scmi_requested_devices_nh, + &info->dev_req_nb); +clear_txrx_setup: + scmi_cleanup_txrx_channels(info); +clear_ida: + return ret; +} + +/* Each compatible listed below must have descriptor associated with it */ +static const struct of_device_id scmi_of_match[] = { +#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}, +#endif + { /* Sentinel */ }, +}; + +MODULE_DEVICE_TABLE(of, scmi_of_match); + +static struct driver arm_scmi_driver = { + .name = "arm-scmi", + .of_match_table = scmi_of_match, + .probe = scmi_probe, +}; +core_platform_driver(arm_scmi_driver); + +static int __init scmi_bus_driver_init(void) +{ + int ret; + + ret = scmi_bus_init(); + if (ret) + return ret; + + /* Bail out if no SCMI transport was configured */ + if (WARN_ON(!IS_ENABLED(CONFIG_ARM_SCMI_HAVE_TRANSPORT))) + return -EINVAL; + + scmi_base_register(); + + scmi_clock_register(); + scmi_power_register(); + scmi_reset_register(); + scmi_sensors_register(); + scmi_voltage_register(); + + return 0; +} +pure_initcall(scmi_bus_driver_init); + +MODULE_ALIAS("platform:arm-scmi"); +MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); +MODULE_DESCRIPTION("ARM SCMI protocol driver"); +MODULE_LICENSE("GPL v2"); |