diff options
| -rw-r--r-- | drivers/firmware/arm_scmi/notify.c | 726 | ||||
| -rw-r--r-- | include/linux/scmi_protocol.h | 46 |
2 files changed, 772 insertions, 0 deletions
diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c index 0505433043d8..79615eef0148 100644 --- a/drivers/firmware/arm_scmi/notify.c +++ b/drivers/firmware/arm_scmi/notify.c @@ -19,18 +19,50 @@ * this core its set of supported events using scmi_register_protocol_events(): * all the needed descriptors are stored in the &struct registered_protocols and * &struct registered_events arrays. + * + * Kernel users interested in some specific event can register their callbacks + * providing the usual notifier_block descriptor, since this core implements + * events' delivery using the standard Kernel notification chains machinery. + * + * Given the number of possible events defined by SCMI and the extensibility + * of the SCMI Protocol itself, the underlying notification chains are created + * and destroyed dynamically on demand depending on the number of users + * effectively registered for an event, so that no support structures or chains + * are allocated until at least one user has registered a notifier_block for + * such event. Similarly, events' generation itself is enabled at the platform + * level only after at least one user has registered, and it is shutdown after + * the last user for that event has gone. + * + * All users provided callbacks and allocated notification-chains are stored in + * the @registered_events_handlers hashtable. Callbacks' registration requests + * for still to be registered events are instead kept in the dedicated common + * hashtable @pending_events_handlers. + * + * An event is identified univocally by the tuple (proto_id, evt_id, src_id) + * and is served by its own dedicated notification chain; information contained + * in such tuples is used, in a few different ways, to generate the needed + * hash-keys. + * + * Here proto_id and evt_id are simply the protocol_id and message_id numbers + * as described in the SCMI Protocol specification, while src_id represents an + * optional, protocol dependent, source identifier (like domain_id, perf_id + * or sensor_id and so forth). */ #define dev_fmt(fmt) "SCMI Notifications - " fmt +#define pr_fmt(fmt) "SCMI Notifications - " fmt #include <linux/bitfield.h> #include <linux/bug.h> #include <linux/compiler.h> #include <linux/device.h> #include <linux/err.h> +#include <linux/hashtable.h> #include <linux/kernel.h> #include <linux/kfifo.h> +#include <linux/list.h> #include <linux/mutex.h> +#include <linux/notifier.h> #include <linux/refcount.h> #include <linux/scmi_protocol.h> #include <linux/slab.h> @@ -55,6 +87,86 @@ #define MAKE_ALL_SRCS_KEY(p, e) MAKE_HASH_KEY((p), (e), SRC_ID_MASK) +/* + * Assumes that the stored obj includes its own hash-key in a field named 'key': + * with this simplification this macro can be equally used for all the objects' + * types hashed by this implementation. + * + * @__ht: The hashtable name + * @__obj: A pointer to the object type to be retrieved from the hashtable; + * it will be used as a cursor while scanning the hastable and it will + * be possibly left as NULL when @__k is not found + * @__k: The key to search for + */ +#define KEY_FIND(__ht, __obj, __k) \ +({ \ + typeof(__k) k_ = __k; \ + typeof(__obj) obj_; \ + \ + hash_for_each_possible((__ht), obj_, hash, k_) \ + if (obj_->key == k_) \ + break; \ + __obj = obj_; \ +}) + +#define KEY_XTRACT_PROTO_ID(key) FIELD_GET(PROTO_ID_MASK, (key)) +#define KEY_XTRACT_EVT_ID(key) FIELD_GET(EVT_ID_MASK, (key)) +#define KEY_XTRACT_SRC_ID(key) FIELD_GET(SRC_ID_MASK, (key)) + +/* + * A set of macros used to access safely @registered_protocols and + * @registered_events arrays; these are fixed in size and each entry is possibly + * populated at protocols' registration time and then only read but NEVER + * modified or removed. + */ +#define SCMI_GET_PROTO(__ni, __pid) \ +({ \ + typeof(__ni) ni_ = __ni; \ + struct scmi_registered_events_desc *__pd = NULL; \ + \ + if (ni_) \ + __pd = READ_ONCE(ni_->registered_protocols[(__pid)]); \ + __pd; \ +}) + +#define SCMI_GET_REVT_FROM_PD(__pd, __eid) \ +({ \ + typeof(__pd) pd_ = __pd; \ + typeof(__eid) eid_ = __eid; \ + struct scmi_registered_event *__revt = NULL; \ + \ + if (pd_ && eid_ < pd_->num_events) \ + __revt = READ_ONCE(pd_->registered_events[eid_]); \ + __revt; \ +}) + +#define SCMI_GET_REVT(__ni, __pid, __eid) \ +({ \ + struct scmi_registered_event *__revt; \ + struct scmi_registered_events_desc *__pd; \ + \ + __pd = SCMI_GET_PROTO((__ni), (__pid)); \ + __revt = SCMI_GET_REVT_FROM_PD(__pd, (__eid)); \ + __revt; \ +}) + +/* A couple of utility macros to limit cruft when calling protocols' helpers */ +#define REVT_NOTIFY_SET_STATUS(revt, eid, sid, state) \ +({ \ + typeof(revt) r = revt; \ + r->proto->ops->set_notify_enabled(r->proto->ni->handle, \ + (eid), (sid), (state)); \ +}) + +#define REVT_NOTIFY_ENABLE(revt, eid, sid) \ + REVT_NOTIFY_SET_STATUS((revt), (eid), (sid), true) + +#define REVT_NOTIFY_DISABLE(revt, eid, sid) \ + REVT_NOTIFY_SET_STATUS((revt), (eid), (sid), false) + +#define SCMI_PENDING_HASH_SZ 4 +#define SCMI_REGISTERED_HASH_SZ 6 + struct scmi_registered_events_desc; /** @@ -62,9 +174,13 @@ struct scmi_registered_events_desc; * core * @gid: GroupID used for devres * @handle: A reference to the platform instance + * @init_work: A work item to perform final initializations of pending handlers + * @pending_mtx: A mutex to protect @pending_events_handlers * @registered_protocols: A statically allocated array containing pointers to * all the registered protocol-level specific information * related to events' handling + * @pending_events_handlers: An hashtable containing all pending events' + * handlers descriptors * * Each platform instance, represented by a handle, has its own instance of * the notification subsystem represented by this structure. @@ -72,7 +188,11 @@ struct scmi_registered_events_desc; struct scmi_notify_instance { void *gid; struct scmi_handle *handle; + struct work_struct init_work; + /* lock to protect pending_events_handlers */ + struct mutex pending_mtx; struct scmi_registered_events_desc **registered_protocols; + DECLARE_HASHTABLE(pending_events_handlers, SCMI_PENDING_HASH_SZ); }; /** @@ -121,6 +241,9 @@ struct scmi_registered_event; * @registered_events: A dynamically allocated array holding all the registered * events' descriptors, whose fixed-size is determined at * compile time. + * @registered_mtx: A mutex to protect @registered_events_handlers + * @registered_events_handlers: An hashtable containing all events' handlers + * descriptors registered for this protocol * * All protocols that register at least one event have their protocol-specific * information stored here, together with the embedded allocated events_queue. @@ -141,6 +264,9 @@ struct scmi_registered_events_desc { void *in_flight; int num_events; struct scmi_registered_event **registered_events; + /* mutex to protect registered_events_handlers */ + struct mutex registered_mtx; + DECLARE_HASHTABLE(registered_events_handlers, SCMI_REGISTERED_HASH_SZ); }; /** @@ -174,6 +300,38 @@ struct scmi_registered_event { }; /** + * struct scmi_event_handler - Event handler information + * @key: The used hashkey + * @users: A reference count for number of active users for this handler + * @r_evt: A reference to the associated registered event; when this is NULL + * this handler is pending, which means that identifies a set of + * callbacks intended to be attached to an event which is still not + * known nor registered by any protocol at that point in time + * @chain: The notification chain dedicated to this specific event tuple + * @hash: The hlist_node used for collision handling + * @enabled: A boolean which records if event's generation has been already + * enabled for this handler as a whole + * + * This structure collects all the information needed to process a received + * event identified by the tuple (proto_id, evt_id, src_id). + * These descriptors are stored in a per-protocol @registered_events_handlers + * table using as a key a value derived from that tuple. + */ +struct scmi_event_handler { + u32 key; + refcount_t users; + struct scmi_registered_event *r_evt; + struct blocking_notifier_head chain; + struct hlist_node hash; + bool enabled; +}; + +#define IS_HNDL_PENDING(hndl) (!(hndl)->r_evt) + +static void scmi_put_handler_unlocked(struct scmi_notify_instance *ni, + struct scmi_event_handler *hndl); + +/** * scmi_kfifo_free() - Devres action helper to free the kfifo * @kfifo: The kfifo to free */ @@ -258,6 +416,10 @@ scmi_allocate_registered_events_desc(struct scmi_notify_instance *ni, return ERR_PTR(-ENOMEM); pd->num_events = num_events; + /* Initialize per protocol handlers table */ + mutex_init(&pd->registered_mtx); + hash_init(pd->registered_events_handlers); + return pd; } @@ -349,6 +511,12 @@ int scmi_register_protocol_events(const struct scmi_handle *handle, devres_close_group(ni->handle->dev, ni->gid); + /* + * Finalize any pending events' handler which could have been waiting + * for this protocol's events registration. + */ + schedule_work(&ni->init_work); + return 0; err: @@ -360,6 +528,558 @@ err: } /** + * scmi_allocate_event_handler() - Allocate Event handler + * @ni: A reference to the notification instance to use + * @evt_key: 32bit key uniquely bind to the event identified by the tuple + * (proto_id, evt_id, src_id) + * + * Allocate an event handler and related notification chain associated with + * the provided event handler key. + * Note that, at this point, a related registered_event is still to be + * associated to this handler descriptor (hndl->r_evt == NULL), so the handler + * is initialized as pending. + * + * Context: Assumes to be called with @pending_mtx already acquired. + * Return: the freshly allocated structure on Success + */ +static struct scmi_event_handler * +scmi_allocate_event_handler(struct scmi_notify_instance *ni, u32 evt_key) +{ + struct scmi_event_handler *hndl; + + hndl = kzalloc(sizeof(*hndl), GFP_KERNEL); + if (!hndl) + return NULL; + hndl->key = evt_key; + BLOCKING_INIT_NOTIFIER_HEAD(&hndl->chain); + refcount_set(&hndl->users, 1); + /* New handlers are created pending */ + hash_add(ni->pending_events_handlers, &hndl->hash, hndl->key); + + return hndl; +} + +/** + * scmi_free_event_handler() - Free the provided Event handler + * @hndl: The event handler structure to free + * + * Context: Assumes to be called with proper locking acquired depending + * on the situation. + */ +static void scmi_free_event_handler(struct scmi_event_handler *hndl) +{ + hash_del(&hndl->hash); + kfree(hndl); +} + +/** + * scmi_bind_event_handler() - Helper to attempt binding an handler to an event + * @ni: A reference to the notification instance to use + * @hndl: The event handler to bind + * + * If an associated registered event is found, move the handler from the pending + * into the registered table. + * + * Context: Assumes to be called with @pending_mtx already acquired. + * + * Return: 0 on Success + */ +static inline int scmi_bind_event_handler(struct scmi_notify_instance *ni, + struct scmi_event_handler *hndl) +{ + struct scmi_registered_event *r_evt; + + r_evt = SCMI_GET_REVT(ni, KEY_XTRACT_PROTO_ID(hndl->key), + KEY_XTRACT_EVT_ID(hndl->key)); + if (!r_evt) + return -EINVAL; + + /* Remove from pending and insert into registered */ + hash_del(&hndl->hash); + hndl->r_evt = r_evt; + mutex_lock(&r_evt->proto->registered_mtx); + hash_add(r_evt->proto->registered_events_handlers, + &hndl->hash, hndl->key); + mutex_unlock(&r_evt->proto->registered_mtx); + + return 0; +} + +/** + * scmi_valid_pending_handler() - Helper to check pending status of handlers + * @ni: A reference to the notification instance to use + * @hndl: The event handler to check + * + * An handler is considered pending when its r_evt == NULL, because the related + * event was still unknown at handler's registration time; anyway, since all + * protocols register their supported events once for all at protocols' + * initialization time, a pending handler cannot be considered valid anymore if + * the underlying event (which it is waiting for), belongs to an already + * initialized and registered protocol. + * + * Return: 0 on Success + */ +static inline int scmi_valid_pending_handler(struct scmi_notify_instance *ni, + struct scmi_event_handler *hndl) +{ + struct scmi_registered_events_desc *pd; + + if (!IS_HNDL_PENDING(hndl)) + return -EINVAL; + + pd = SCMI_GET_PROTO(ni, KEY_XTRACT_PROTO_ID(hndl->key)); + if (pd) + return -EINVAL; + + return 0; +} + +/** + * scmi_register_event_handler() - Register whenever possible an Event handler + * @ni: A reference to the notification instance to use + * @hndl: The event handler to register + * + * At first try to bind an event handler to its associated event, then check if + * it was at least a valid pending handler: if it was not bound nor valid return + * false. + * + * Valid pending incomplete bindings will be periodically retried by a dedicated + * worker which is kicked each time a new protocol completes its own + * registration phase. + * + * Context: Assumes to be called with @pending_mtx acquired. + * + * Return: 0 on Success + */ +static int scmi_register_event_handler(struct scmi_notify_instance *ni, + struct scmi_event_handler *hndl) +{ + int ret; + + ret = scmi_bind_event_handler(ni, hndl); + if (!ret) { + dev_dbg(ni->handle->dev, "registered NEW handler - key:%X\n", + hndl->key); + } else { + ret = scmi_valid_pending_handler(ni, hndl); + if (!ret) + dev_dbg(ni->handle->dev, + "registered PENDING handler - key:%X\n", + hndl->key); + } + + return ret; +} + +/** + * __scmi_event_handler_get_ops() - Utility to get or create an event handler + * @ni: A reference to the notification instance to use + * @evt_key: The event key to use + * @create: A boolean flag to specify if a handler must be created when + * not already existent + * + * Search for the desired handler matching the key in both the per-protocol + * registered table and the common pending table: + * * if found adjust users refcount + * * if not found and @create is true, create and register the new handler: + * handler could end up being registered as pending if no matching event + * could be found. + * + * An handler is guaranteed to reside in one and only one of the tables at + * any one time; to ensure this the whole search and create is performed + * holding the @pending_mtx lock, with @registered_mtx additionally acquired + * if needed. + * + * Note that when a nested acquisition of these mutexes is needed the locking + * order is always (same as in @init_work): + * 1. pending_mtx + * 2. registered_mtx + * + * Events generation is NOT enabled right after creation within this routine + * since at creation time we usually want to have all setup and ready before + * events really start flowing. + * + * Return: A properly refcounted handler on Success, NULL on Failure + */ +static inline struct scmi_event_handler * +__scmi_event_handler_get_ops(struct scmi_notify_instance *ni, + u32 evt_key, bool create) +{ + struct scmi_registered_event *r_evt; + struct scmi_event_handler *hndl = NULL; + + r_evt = SCMI_GET_REVT(ni, KEY_XTRACT_PROTO_ID(evt_key), + KEY_XTRACT_EVT_ID(evt_key)); + + mutex_lock(&ni->pending_mtx); + /* Search registered events at first ... if possible at all */ + if (r_evt) { + mutex_lock(&r_evt->proto->registered_mtx); + hndl = KEY_FIND(r_evt->proto->registered_events_handlers, + hndl, evt_key); + if (hndl) + refcount_inc(&hndl->users); + mutex_unlock(&r_evt->proto->registered_mtx); + } + + /* ...then amongst pending. */ + if (!hndl) { + hndl = KEY_FIND(ni->pending_events_handlers, hndl, evt_key); + if (hndl) + refcount_inc(&hndl->users); + } + + /* Create if still not found and required */ + if (!hndl && create) { + hndl = scmi_allocate_event_handler(ni, evt_key); + if (hndl && scmi_register_event_handler(ni, hndl)) { + dev_dbg(ni->handle->dev, + "purging UNKNOWN handler - key:%X\n", + hndl->key); + /* this hndl can be only a pending one */ + scmi_put_handler_unlocked(ni, hndl); + hndl = NULL; + } + } + mutex_unlock(&ni->pending_mtx); + + return hndl; +} + +static struct scmi_event_handler * +scmi_get_handler(struct scmi_notify_instance *ni, u32 evt_key) +{ + return __scmi_event_handler_get_ops(ni, evt_key, false); +} + +static struct scmi_event_handler * +scmi_get_or_create_handler(struct scmi_notify_instance *ni, u32 evt_key) +{ + return __scmi_event_handler_get_ops(ni, evt_key, true); +} + +/** + * __scmi_enable_evt() - Enable/disable events generation + * @r_evt: The registered event to act upon + * @src_id: The src_id to act upon + * @enable: The action to perform: true->Enable, false->Disable + * + * Takes care of proper refcounting while performing enable/disable: handles + * the special case of ALL sources requests by itself. + * Returns successfully if at least one of the required src_id has been + * successfully enabled/disabled. + * + * Return: 0 on Success + */ +static inline int __scmi_enable_evt(struct scmi_registered_event *r_evt, + u32 src_id, bool enable) +{ + int retvals = 0; + u32 num_sources; + refcount_t *sid; + + if (src_id == SRC_ID_MASK) { + src_id = 0; + num_sources = r_evt->num_sources; + } else if (src_id < r_evt->num_sources) { + num_sources = 1; + } else { + return -EINVAL; + } + + mutex_lock(&r_evt->sources_mtx); + if (enable) { + for (; num_sources; src_id++, num_sources--) { + int ret = 0; + + sid = &r_evt->sources[src_id]; + if (refcount_read(sid) == 0) { + ret = REVT_NOTIFY_ENABLE(r_evt, r_evt->evt->id, + src_id); + if (!ret) + refcount_set(sid, 1); + } else { + refcount_inc(sid); + } + retvals += !ret; + } + } else { + for (; num_sources; src_id++, num_sources--) { + sid = &r_evt->sources[src_id]; + if (refcount_dec_and_test(sid)) + REVT_NOTIFY_DISABLE(r_evt, + r_evt->evt->id, src_id); + } + retvals = 1; + } + mutex_unlock(&r_evt->sources_mtx); + + return retvals ? 0 : -EINVAL; +} + +static int scmi_enable_events(struct scmi_event_handler *hndl) +{ + int ret = 0; + + if (!hndl->enabled) { + ret = __scmi_enable_evt(hndl->r_evt, + KEY_XTRACT_SRC_ID(hndl->key), true); + if (!ret) + hndl->enabled = true; + } + + return ret; +} + +static int scmi_disable_events(struct scmi_event_handler *hndl) +{ + int ret = 0; + + if (hndl->enabled) { + ret = __scmi_enable_evt(hndl->r_evt, + KEY_XTRACT_SRC_ID(hndl->key), false); + if (!ret) + hndl->enabled = false; + } + + return ret; +} + +/** + * scmi_put_handler_unlocked() - Put an event handler + * @ni: A reference to the notification instance to use + * @hndl: The event handler to act upon + * + * After having got exclusive access to the registered handlers hashtable, + * update the refcount and if @hndl is no more in use by anyone: + * * ask for events' generation disabling + * * unregister and free the handler itself + * + * Context: Assumes all the proper locking has been managed by the caller. + */ +static void scmi_put_handler_unlocked(struct scmi_notify_instance *ni, + struct scmi_event_handler *hndl) +{ + if (refcount_dec_and_test(&hndl->users)) { + if (!IS_HNDL_PENDING(hndl)) + scmi_disable_events(hndl); + scmi_free_event_handler(hndl); + } +} + +static void scmi_put_handler(struct scmi_notify_instance *ni, + struct scmi_event_handler *hndl) +{ + struct scmi_registered_event *r_evt = hndl->r_evt; + + mutex_lock(&ni->pending_mtx); + if (r_evt) + mutex_lock(&r_evt->proto->registered_mtx); + + scmi_put_handler_unlocked(ni, hndl); + + if (r_evt) + mutex_unlock(&r_evt->proto->registered_mtx); + mutex_unlock(&ni->pending_mtx); +} + +/** + * scmi_event_handler_enable_events() - Enable events associated to an handler + * @hndl: The Event handler to act upon + * + * Return: 0 on Success + */ +static int scmi_event_handler_enable_events(struct scmi_event_handler *hndl) +{ + if (scmi_enable_events(hndl)) { + pr_err("Failed to ENABLE events for key:%X !\n", hndl->key); + return -EINVAL; + } + + return 0; +} + +/** + * scmi_register_notifier() - Register a notifier_block for an event + * @handle: The handle identifying the platform instance against which the + * callback is registered + * @proto_id: Protocol ID + * @evt_id: Event ID + * @src_id: Source ID, when NULL register for events coming form ALL possible + * sources + * @nb: A standard notifier block to register for the specified event + * + * Generic helper to register a notifier_block against a protocol event. + * + * A notifier_block @nb will be registered for each distinct event identified + * by the tuple (proto_id, evt_id, src_id) on a dedicated notification chain + * so that: + * + * (proto_X, evt_Y, src_Z) --> chain_X_Y_Z + * + * @src_id meaning is protocol specific and identifies the origin of the event + * (like domain_id, sensor_id and so forth). + * + * @src_id can be NULL to signify that the caller is interested in receiving + * notifications from ALL the available sources for that protocol OR simply that + * the protocol does not support distinct sources. + * + * As soon as one user for the specified tuple appears, an handler is created, + * and that specific event's generation is enabled at the platform level, unless + * an associated registered event is found missing, meaning that the needed + * protocol is still to be initialized and the handler has just been registered + * as still pending. + * + * Return: 0 on Success + */ +static int scmi_register_notifier(const struct scmi_handle *handle, + u8 proto_id, u8 evt_id, u32 *src_id, + struct notifier_block *nb) +{ + int ret = 0; + u32 evt_key; + struct scmi_event_handler *hndl; + struct scmi_notify_instance *ni; + + /* Ensure notify_priv is updated */ + smp_rmb(); + if (!handle->notify_priv) + return -ENODEV; + ni = handle->notify_priv; + + evt_key = MAKE_HASH_KEY(proto_id, evt_id, + src_id ? *src_id : SRC_ID_MASK); + hndl = scmi_get_or_create_handler(ni, evt_key); + if (!hndl) + return -EINVAL; + + blocking_notifier_chain_register(&hndl->chain, nb); + + /* Enable events for not pending handlers */ + if (!IS_HNDL_PENDING(hndl)) { + ret = scmi_event_handler_enable_events(hndl); + if (ret) + scmi_put_handler(ni, hndl); + } + + return ret; +} + +/** + * scmi_unregister_notifier() - Unregister a notifier_block for an event + * @handle: The handle identifying the platform instance against which the + * callback is unregistered + * @proto_id: Protocol ID + * @evt_id: Event ID + * @src_id: Source ID + * @nb: The notifier_block to unregister + * + * Takes care to unregister the provided @nb from the notification chain + * associated to the specified event and, if there are no more users for the + * event handler, frees also the associated event handler structures. + * (this could possibly cause disabling of event's generation at platform level) + * + * Return: 0 on Success + */ +static int scmi_unregister_notifier(const struct scmi_handle *handle, + u8 proto_id, u8 evt_id, u32 *src_id, + struct notifier_block *nb) +{ + u32 evt_key; + struct scmi_event_handler *hndl; + struct scmi_notify_instance *ni; + + /* Ensure notify_priv is updated */ + smp_rmb(); + if (!handle->notify_priv) + return -ENODEV; + ni = handle->notify_priv; + + evt_key = MAKE_HASH_KEY(proto_id, evt_id, + src_id ? *src_id : SRC_ID_MASK); + hndl = scmi_get_handler(ni, evt_key); + if (!hndl) + return -EINVAL; + + /* + * Note that this chain unregistration call is safe on its own + * being internally protected by an rwsem. + */ + blocking_notifier_chain_unregister(&hndl->chain, nb); + scmi_put_handler(ni, hndl); + + /* + * This balances the initial get issued in @scmi_register_notifier. + * If this notifier_block happened to be the last known user callback + * for this event, the handler is here freed and the event's generation + * stopped. + * + * Note that, an ongoing concurrent lookup on the delivery workqueue + * path could still hold the refcount to 1 even after this routine + * completes: in such a case it will be the final put on the delivery + * path which will finally free this unused handler. + */ + scmi_put_handler(ni, hndl); + + return 0; +} + +/** + * scmi_protocols_late_init() - Worker for late initialization + * @work: The work item to use associated to the proper SCMI instance + * + * This kicks in whenever a new protocol has completed its own registration via + * scmi_register_protocol_events(): it is in charge of scanning the table of + * pending handlers (registered by users while the related protocol was still + * not initialized) and finalizing their initialization whenever possible; + * invalid pending handlers are purged at this point in time. + */ +static void scmi_protocols_late_init(struct work_struct *work) +{ + int bkt; + struct scmi_event_handler *hndl; + struct scmi_notify_instance *ni; + struct hlist_node *tmp; + + ni = container_of(work, struct scmi_notify_instance, init_work); + + /* Ensure protocols and events are up to date */ + smp_rmb(); + + mutex_lock(&ni->pending_mtx); + hash_for_each_safe(ni->pending_events_handlers, bkt, tmp, hndl, hash) { + int ret; + + ret = scmi_bind_event_handler(ni, hndl); + if (!ret) { + dev_dbg(ni->handle->dev, + "finalized PENDING handler - key:%X\n", + hndl->key); + ret = scmi_event_handler_enable_events(hndl); + } else { + ret = scmi_valid_pending_handler(ni, hndl); + } + if (ret) { + dev_dbg(ni->handle->dev, + "purging PENDING handler - key:%X\n", + hndl->key); + /* this hndl can be only a pending one */ + scmi_put_handler_unlocked(ni, hndl); + } + } + mutex_unlock(&ni->pending_mtx); +} + +/* + * notify_ops are attached to the handle so that can be accessed + * directly from an scmi_driver to register its own notifiers. + */ +static struct scmi_notify_ops notify_ops = { + .register_event_notifier = scmi_register_notifier, + .unregister_event_notifier = scmi_unregister_notifier, +}; + +/** * scmi_notification_init() - Initializes Notification Core Support * @handle: The handle identifying the platform instance to initialize * @@ -406,6 +1126,12 @@ int scmi_notification_init(struct scmi_handle *handle) if (!ni->registered_protocols) goto err; + mutex_init(&ni->pending_mtx); + hash_init(ni->pending_events_handlers); + + INIT_WORK(&ni->init_work, scmi_protocols_late_init); + + handle->notify_ops = ¬ify_ops; handle->notify_priv = ni; /* Ensure handle is up to date */ smp_wmb(); diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h index 9a34b02a9cce..26957d6872a5 100644 --- a/include/linux/scmi_protocol.h +++ b/include/linux/scmi_protocol.h @@ -9,6 +9,7 @@ #define _LINUX_SCMI_PROTOCOL_H #include <linux/device.h> +#include <linux/notifier.h> #include <linux/types.h> #define SCMI_MAX_STR_SIZE 16 @@ -214,6 +215,49 @@ struct scmi_reset_ops { }; /** + * struct scmi_notify_ops - represents notifications' operations provided by + * SCMI core + * @register_event_notifier: Register a notifier_block for the requested event + * @unregister_event_notifier: Unregister a notifier_block for the requested + * event + * + * A user can register/unregister its own notifier_block against the wanted + * platform instance regarding the desired event identified by the + * tuple: (proto_id, evt_id, src_id) using the provided register/unregister + * interface where: + * + * @handle: The handle identifying the platform instance to use + * @proto_id: The protocol ID as in SCMI Specification + * @evt_id: The message ID of the desired event as in SCMI Specification + * @src_id: A pointer to the desired source ID if different sources are + * possible for the protocol (like domain_id, sensor_id...etc) + * + * @src_id can be provided as NULL if it simply does NOT make sense for + * the protocol at hand, OR if the user is explicitly interested in + * receiving notifications from ANY existent source associated to the + * specified proto_id / evt_id. + * + * Received notifications are finally delivered to the registered users, + * invoking the callback provided with the notifier_block *nb as follows: + * + * int user_cb(nb, evt_id, report) + * + * with: + * + * @nb: The notifier block provided by the user + * @evt_id: The message ID of the delivered event + * @report: A custom struct describing the specific event delivered + */ +struct scmi_notify_ops { + int (*register_event_notifier)(const struct scmi_handle *handle, + u8 proto_id, u8 evt_id, u32 *src_id, + struct notifier_block *nb); + int (*unregister_event_notifier)(const struct scmi_handle *handle, + u8 proto_id, u8 evt_id, u32 *src_id, + struct notifier_block *nb); +}; + +/** * struct scmi_handle - Handle returned to ARM SCMI clients for usage. * * @dev: pointer to the SCMI device @@ -223,6 +267,7 @@ struct scmi_reset_ops { * @clk_ops: pointer to set of clock protocol operations * @sensor_ops: pointer to set of sensor protocol operations * @reset_ops: pointer to set of reset protocol operations + * @notify_ops: pointer to set of notifications related operations * @perf_priv: pointer to private data structure specific to performance * protocol(for internal use only) * @clk_priv: pointer to private data structure specific to clock @@ -244,6 +289,7 @@ struct scmi_handle { struct scmi_power_ops *power_ops; struct scmi_sensor_ops *sensor_ops; struct scmi_reset_ops *reset_ops; + struct scmi_notify_ops *notify_ops; /* for protocol internal use */ void *perf_priv; void *clk_priv; |