| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Maximilian Luz | 7722 | 99.96% | 14 | 87.50% |
| Tian Tao | 2 | 0.03% | 1 | 6.25% |
| Dan Carpenter | 1 | 0.01% | 1 | 6.25% |
| Total | 7725 | 16 |
// SPDX-License-Identifier: GPL-2.0+ /* * Main SSAM/SSH controller structure and functionality. * * Copyright (C) 2019-2022 Maximilian Luz <luzmaximilian@gmail.com> */ #include <linux/acpi.h> #include <linux/atomic.h> #include <linux/completion.h> #include <linux/gpio/consumer.h> #include <linux/interrupt.h> #include <linux/kref.h> #include <linux/limits.h> #include <linux/list.h> #include <linux/lockdep.h> #include <linux/mutex.h> #include <linux/rculist.h> #include <linux/rbtree.h> #include <linux/rwsem.h> #include <linux/serdev.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/srcu.h> #include <linux/types.h> #include <linux/workqueue.h> #include <linux/surface_aggregator/controller.h> #include <linux/surface_aggregator/serial_hub.h> #include "controller.h" #include "ssh_msgb.h" #include "ssh_request_layer.h" #include "trace.h" /* -- Safe counters. -------------------------------------------------------- */ /** * ssh_seq_reset() - Reset/initialize sequence ID counter. * @c: The counter to reset. */ static void ssh_seq_reset(struct ssh_seq_counter *c) { WRITE_ONCE(c->value, 0); } /** * ssh_seq_next() - Get next sequence ID. * @c: The counter providing the sequence IDs. * * Return: Returns the next sequence ID of the counter. */ static u8 ssh_seq_next(struct ssh_seq_counter *c) { u8 old = READ_ONCE(c->value); u8 new = old + 1; u8 ret; while (unlikely((ret = cmpxchg(&c->value, old, new)) != old)) { old = ret; new = old + 1; } return old; } /** * ssh_rqid_reset() - Reset/initialize request ID counter. * @c: The counter to reset. */ static void ssh_rqid_reset(struct ssh_rqid_counter *c) { WRITE_ONCE(c->value, 0); } /** * ssh_rqid_next() - Get next request ID. * @c: The counter providing the request IDs. * * Return: Returns the next request ID of the counter, skipping any reserved * request IDs. */ static u16 ssh_rqid_next(struct ssh_rqid_counter *c) { u16 old = READ_ONCE(c->value); u16 new = ssh_rqid_next_valid(old); u16 ret; while (unlikely((ret = cmpxchg(&c->value, old, new)) != old)) { old = ret; new = ssh_rqid_next_valid(old); } return old; } /* -- Event notifier/callbacks. --------------------------------------------- */ /* * The notifier system is based on linux/notifier.h, specifically the SRCU * implementation. The difference to that is, that some bits of the notifier * call return value can be tracked across multiple calls. This is done so * that handling of events can be tracked and a warning can be issued in case * an event goes unhandled. The idea of that warning is that it should help * discover and identify new/currently unimplemented features. */ /** * ssam_event_matches_notifier() - Test if an event matches a notifier. * @n: The event notifier to test against. * @event: The event to test. * * Return: Returns %true if the given event matches the given notifier * according to the rules set in the notifier's event mask, %false otherwise. */ static bool ssam_event_matches_notifier(const struct ssam_event_notifier *n, const struct ssam_event *event) { bool match = n->event.id.target_category == event->target_category; if (n->event.mask & SSAM_EVENT_MASK_TARGET) match &= n->event.reg.target_id == event->target_id; if (n->event.mask & SSAM_EVENT_MASK_INSTANCE) match &= n->event.id.instance == event->instance_id; return match; } /** * ssam_nfblk_call_chain() - Call event notifier callbacks of the given chain. * @nh: The notifier head for which the notifier callbacks should be called. * @event: The event data provided to the callbacks. * * Call all registered notifier callbacks in order of their priority until * either no notifier is left or a notifier returns a value with the * %SSAM_NOTIF_STOP bit set. Note that this bit is automatically set via * ssam_notifier_from_errno() on any non-zero error value. * * Return: Returns the notifier status value, which contains the notifier * status bits (%SSAM_NOTIF_HANDLED and %SSAM_NOTIF_STOP) as well as a * potential error value returned from the last executed notifier callback. * Use ssam_notifier_to_errno() to convert this value to the original error * value. */ static int ssam_nfblk_call_chain(struct ssam_nf_head *nh, struct ssam_event *event) { struct ssam_event_notifier *nf; int ret = 0, idx; idx = srcu_read_lock(&nh->srcu); list_for_each_entry_rcu(nf, &nh->head, base.node, srcu_read_lock_held(&nh->srcu)) { if (ssam_event_matches_notifier(nf, event)) { ret = (ret & SSAM_NOTIF_STATE_MASK) | nf->base.fn(nf, event); if (ret & SSAM_NOTIF_STOP) break; } } srcu_read_unlock(&nh->srcu, idx); return ret; } /** * ssam_nfblk_insert() - Insert a new notifier block into the given notifier * list. * @nh: The notifier head into which the block should be inserted. * @nb: The notifier block to add. * * Note: This function must be synchronized by the caller with respect to other * insert, find, and/or remove calls by holding ``struct ssam_nf.lock``. * * Return: Returns zero on success, %-EEXIST if the notifier block has already * been registered. */ static int ssam_nfblk_insert(struct ssam_nf_head *nh, struct ssam_notifier_block *nb) { struct ssam_notifier_block *p; struct list_head *h; /* Runs under lock, no need for RCU variant. */ list_for_each(h, &nh->head) { p = list_entry(h, struct ssam_notifier_block, node); if (unlikely(p == nb)) { WARN(1, "double register detected"); return -EEXIST; } if (nb->priority > p->priority) break; } list_add_tail_rcu(&nb->node, h); return 0; } /** * ssam_nfblk_find() - Check if a notifier block is registered on the given * notifier head. * list. * @nh: The notifier head on which to search. * @nb: The notifier block to search for. * * Note: This function must be synchronized by the caller with respect to other * insert, find, and/or remove calls by holding ``struct ssam_nf.lock``. * * Return: Returns true if the given notifier block is registered on the given * notifier head, false otherwise. */ static bool ssam_nfblk_find(struct ssam_nf_head *nh, struct ssam_notifier_block *nb) { struct ssam_notifier_block *p; /* Runs under lock, no need for RCU variant. */ list_for_each_entry(p, &nh->head, node) { if (p == nb) return true; } return false; } /** * ssam_nfblk_remove() - Remove a notifier block from its notifier list. * @nb: The notifier block to be removed. * * Note: This function must be synchronized by the caller with respect to * other insert, find, and/or remove calls by holding ``struct ssam_nf.lock``. * Furthermore, the caller _must_ ensure SRCU synchronization by calling * synchronize_srcu() with ``nh->srcu`` after leaving the critical section, to * ensure that the removed notifier block is not in use any more. */ static void ssam_nfblk_remove(struct ssam_notifier_block *nb) { list_del_rcu(&nb->node); } /** * ssam_nf_head_init() - Initialize the given notifier head. * @nh: The notifier head to initialize. */ static int ssam_nf_head_init(struct ssam_nf_head *nh) { int status; status = init_srcu_struct(&nh->srcu); if (status) return status; INIT_LIST_HEAD(&nh->head); return 0; } /** * ssam_nf_head_destroy() - Deinitialize the given notifier head. * @nh: The notifier head to deinitialize. */ static void ssam_nf_head_destroy(struct ssam_nf_head *nh) { cleanup_srcu_struct(&nh->srcu); } /* -- Event/notification registry. ------------------------------------------ */ /** * struct ssam_nf_refcount_key - Key used for event activation reference * counting. * @reg: The registry via which the event is enabled/disabled. * @id: The ID uniquely describing the event. */ struct ssam_nf_refcount_key { struct ssam_event_registry reg; struct ssam_event_id id; }; /** * struct ssam_nf_refcount_entry - RB-tree entry for reference counting event * activations. * @node: The node of this entry in the rb-tree. * @key: The key of the event. * @refcount: The reference-count of the event. * @flags: The flags used when enabling the event. */ struct ssam_nf_refcount_entry { struct rb_node node; struct ssam_nf_refcount_key key; int refcount; u8 flags; }; /** * ssam_nf_refcount_inc() - Increment reference-/activation-count of the given * event. * @nf: The notifier system reference. * @reg: The registry used to enable/disable the event. * @id: The event ID. * * Increments the reference-/activation-count associated with the specified * event type/ID, allocating a new entry for this event ID if necessary. A * newly allocated entry will have a refcount of one. * * Note: ``nf->lock`` must be held when calling this function. * * Return: Returns the refcount entry on success. Returns an error pointer * with %-ENOSPC if there have already been %INT_MAX events of the specified * ID and type registered, or %-ENOMEM if the entry could not be allocated. */ static struct ssam_nf_refcount_entry * ssam_nf_refcount_inc(struct ssam_nf *nf, struct ssam_event_registry reg, struct ssam_event_id id) { struct ssam_nf_refcount_entry *entry; struct ssam_nf_refcount_key key; struct rb_node **link = &nf->refcount.rb_node; struct rb_node *parent = NULL; int cmp; lockdep_assert_held(&nf->lock); key.reg = reg; key.id = id; while (*link) { entry = rb_entry(*link, struct ssam_nf_refcount_entry, node); parent = *link; cmp = memcmp(&key, &entry->key, sizeof(key)); if (cmp < 0) { link = &(*link)->rb_left; } else if (cmp > 0) { link = &(*link)->rb_right; } else if (entry->refcount < INT_MAX) { entry->refcount++; return entry; } else { WARN_ON(1); return ERR_PTR(-ENOSPC); } } entry = kzalloc(sizeof(*entry), GFP_KERNEL); if (!entry) return ERR_PTR(-ENOMEM); entry->key = key; entry->refcount = 1; rb_link_node(&entry->node, parent, link); rb_insert_color(&entry->node, &nf->refcount); return entry; } /** * ssam_nf_refcount_dec() - Decrement reference-/activation-count of the given * event. * @nf: The notifier system reference. * @reg: The registry used to enable/disable the event. * @id: The event ID. * * Decrements the reference-/activation-count of the specified event, * returning its entry. If the returned entry has a refcount of zero, the * caller is responsible for freeing it using kfree(). * * Note: ``nf->lock`` must be held when calling this function. * * Return: Returns the refcount entry on success or %NULL if the entry has not * been found. */ static struct ssam_nf_refcount_entry * ssam_nf_refcount_dec(struct ssam_nf *nf, struct ssam_event_registry reg, struct ssam_event_id id) { struct ssam_nf_refcount_entry *entry; struct ssam_nf_refcount_key key; struct rb_node *node = nf->refcount.rb_node; int cmp; lockdep_assert_held(&nf->lock); key.reg = reg; key.id = id; while (node) { entry = rb_entry(node, struct ssam_nf_refcount_entry, node); cmp = memcmp(&key, &entry->key, sizeof(key)); if (cmp < 0) { node = node->rb_left; } else if (cmp > 0) { node = node->rb_right; } else { entry->refcount--; if (entry->refcount == 0) rb_erase(&entry->node, &nf->refcount); return entry; } } return NULL; } /** * ssam_nf_refcount_dec_free() - Decrement reference-/activation-count of the * given event and free its entry if the reference count reaches zero. * @nf: The notifier system reference. * @reg: The registry used to enable/disable the event. * @id: The event ID. * * Decrements the reference-/activation-count of the specified event, freeing * its entry if it reaches zero. * * Note: ``nf->lock`` must be held when calling this function. */ static void ssam_nf_refcount_dec_free(struct ssam_nf *nf, struct ssam_event_registry reg, struct ssam_event_id id) { struct ssam_nf_refcount_entry *entry; lockdep_assert_held(&nf->lock); entry = ssam_nf_refcount_dec(nf, reg, id); if (entry && entry->refcount == 0) kfree(entry); } /** * ssam_nf_refcount_empty() - Test if the notification system has any * enabled/active events. * @nf: The notification system. */ static bool ssam_nf_refcount_empty(struct ssam_nf *nf) { return RB_EMPTY_ROOT(&nf->refcount); } /** * ssam_nf_call() - Call notification callbacks for the provided event. * @nf: The notifier system * @dev: The associated device, only used for logging. * @rqid: The request ID of the event. * @event: The event provided to the callbacks. * * Execute registered callbacks in order of their priority until either no * callback is left or a callback returns a value with the %SSAM_NOTIF_STOP * bit set. Note that this bit is set automatically when converting non-zero * error values via ssam_notifier_from_errno() to notifier values. * * Also note that any callback that could handle an event should return a value * with bit %SSAM_NOTIF_HANDLED set, indicating that the event does not go * unhandled/ignored. In case no registered callback could handle an event, * this function will emit a warning. * * In case a callback failed, this function will emit an error message. */ static void ssam_nf_call(struct ssam_nf *nf, struct device *dev, u16 rqid, struct ssam_event *event) { struct ssam_nf_head *nf_head; int status, nf_ret; if (!ssh_rqid_is_event(rqid)) { dev_warn(dev, "event: unsupported rqid: %#06x\n", rqid); return; } nf_head = &nf->head[ssh_rqid_to_event(rqid)]; nf_ret = ssam_nfblk_call_chain(nf_head, event); status = ssam_notifier_to_errno(nf_ret); if (status < 0) { dev_err(dev, "event: error handling event: %d (tc: %#04x, tid: %#04x, cid: %#04x, iid: %#04x)\n", status, event->target_category, event->target_id, event->command_id, event->instance_id); } else if (!(nf_ret & SSAM_NOTIF_HANDLED)) { dev_warn(dev, "event: unhandled event (rqid: %#04x, tc: %#04x, tid: %#04x, cid: %#04x, iid: %#04x)\n", rqid, event->target_category, event->target_id, event->command_id, event->instance_id); } } /** * ssam_nf_init() - Initialize the notifier system. * @nf: The notifier system to initialize. */ static int ssam_nf_init(struct ssam_nf *nf) { int i, status; for (i = 0; i < SSH_NUM_EVENTS; i++) { status = ssam_nf_head_init(&nf->head[i]); if (status) break; } if (status) { while (i--) ssam_nf_head_destroy(&nf->head[i]); return status; } mutex_init(&nf->lock); return 0; } /** * ssam_nf_destroy() - Deinitialize the notifier system. * @nf: The notifier system to deinitialize. */ static void ssam_nf_destroy(struct ssam_nf *nf) { int i; for (i = 0; i < SSH_NUM_EVENTS; i++) ssam_nf_head_destroy(&nf->head[i]); mutex_destroy(&nf->lock); } /* -- Event/async request completion system. -------------------------------- */ #define SSAM_CPLT_WQ_NAME "ssam_cpltq" /* * SSAM_CPLT_WQ_BATCH - Maximum number of event item completions executed per * work execution. Used to prevent livelocking of the workqueue. Value chosen * via educated guess, may be adjusted. */ #define SSAM_CPLT_WQ_BATCH 10 /* * SSAM_EVENT_ITEM_CACHE_PAYLOAD_LEN - Maximum payload length for a cached * &struct ssam_event_item. * * This length has been chosen to be accommodate standard touchpad and * keyboard input events. Events with larger payloads will be allocated * separately. */ #define SSAM_EVENT_ITEM_CACHE_PAYLOAD_LEN 32 static struct kmem_cache *ssam_event_item_cache; /** * ssam_event_item_cache_init() - Initialize the event item cache. */ int ssam_event_item_cache_init(void) { const unsigned int size = sizeof(struct ssam_event_item) + SSAM_EVENT_ITEM_CACHE_PAYLOAD_LEN; const unsigned int align = __alignof__(struct ssam_event_item); struct kmem_cache *cache; cache = kmem_cache_create("ssam_event_item", size, align, 0, NULL); if (!cache) return -ENOMEM; ssam_event_item_cache = cache; return 0; } /** * ssam_event_item_cache_destroy() - Deinitialize the event item cache. */ void ssam_event_item_cache_destroy(void) { kmem_cache_destroy(ssam_event_item_cache); ssam_event_item_cache = NULL; } static void __ssam_event_item_free_cached(struct ssam_event_item *item) { kmem_cache_free(ssam_event_item_cache, item); } static void __ssam_event_item_free_generic(struct ssam_event_item *item) { kfree(item); } /** * ssam_event_item_free() - Free the provided event item. * @item: The event item to free. */ static void ssam_event_item_free(struct ssam_event_item *item) { trace_ssam_event_item_free(item); item->ops.free(item); } /** * ssam_event_item_alloc() - Allocate an event item with the given payload size. * @len: The event payload length. * @flags: The flags used for allocation. * * Allocate an event item with the given payload size, preferring allocation * from the event item cache if the payload is small enough (i.e. smaller than * %SSAM_EVENT_ITEM_CACHE_PAYLOAD_LEN). Sets the item operations and payload * length values. The item free callback (``ops.free``) should not be * overwritten after this call. * * Return: Returns the newly allocated event item. */ static struct ssam_event_item *ssam_event_item_alloc(size_t len, gfp_t flags) { struct ssam_event_item *item; if (len <= SSAM_EVENT_ITEM_CACHE_PAYLOAD_LEN) { item = kmem_cache_alloc(ssam_event_item_cache, flags); if (!item) return NULL; item->ops.free = __ssam_event_item_free_cached; } else { item = kzalloc(struct_size(item, event.data, len), flags); if (!item) return NULL; item->ops.free = __ssam_event_item_free_generic; } item->event.length = len; trace_ssam_event_item_alloc(item, len); return item; } /** * ssam_event_queue_push() - Push an event item to the event queue. * @q: The event queue. * @item: The item to add. */ static void ssam_event_queue_push(struct ssam_event_queue *q, struct ssam_event_item *item) { spin_lock(&q->lock); list_add_tail(&item->node, &q->head); spin_unlock(&q->lock); } /** * ssam_event_queue_pop() - Pop the next event item from the event queue. * @q: The event queue. * * Returns and removes the next event item from the queue. Returns %NULL If * there is no event item left. */ static struct ssam_event_item *ssam_event_queue_pop(struct ssam_event_queue *q) { struct ssam_event_item *item; spin_lock(&q->lock); item = list_first_entry_or_null(&q->head, struct ssam_event_item, node); if (item) list_del(&item->node); spin_unlock(&q->lock); return item; } /** * ssam_event_queue_is_empty() - Check if the event queue is empty. * @q: The event queue. */ static bool ssam_event_queue_is_empty(struct ssam_event_queue *q) { bool empty; spin_lock(&q->lock); empty = list_empty(&q->head); spin_unlock(&q->lock); return empty; } /** * ssam_cplt_get_event_queue() - Get the event queue for the given parameters. * @cplt: The completion system on which to look for the queue. * @tid: The target ID of the queue. * @rqid: The request ID representing the event ID for which to get the queue. * * Return: Returns the event queue corresponding to the event type described * by the given parameters. If the request ID does not represent an event, * this function returns %NULL. If the target ID is not supported, this * function will fall back to the default target ID (``tid = 1``). */ static struct ssam_event_queue *ssam_cplt_get_event_queue(struct ssam_cplt *cplt, u8 tid, u16 rqid) { u16 event = ssh_rqid_to_event(rqid); u16 tidx = ssh_tid_to_index(tid); if (!ssh_rqid_is_event(rqid)) { dev_err(cplt->dev, "event: unsupported request ID: %#06x\n", rqid); return NULL; } if (!ssh_tid_is_valid(tid)) { dev_warn(cplt->dev, "event: unsupported target ID: %u\n", tid); tidx = 0; } return &cplt->event.target[tidx].queue[event]; } /** * ssam_cplt_submit() - Submit a work item to the completion system workqueue. * @cplt: The completion system. * @work: The work item to submit. */ static bool ssam_cplt_submit(struct ssam_cplt *cplt, struct work_struct *work) { return queue_work(cplt->wq, work); } /** * ssam_cplt_submit_event() - Submit an event to the completion system. * @cplt: The completion system. * @item: The event item to submit. * * Submits the event to the completion system by queuing it on the event item * queue and queuing the respective event queue work item on the completion * workqueue, which will eventually complete the event. * * Return: Returns zero on success, %-EINVAL if there is no event queue that * can handle the given event item. */ static int ssam_cplt_submit_event(struct ssam_cplt *cplt, struct ssam_event_item *item) { struct ssam_event_queue *evq; evq = ssam_cplt_get_event_queue(cplt, item->event.target_id, item->rqid); if (!evq) return -EINVAL; ssam_event_queue_push(evq, item); ssam_cplt_submit(cplt, &evq->work); return 0; } /** * ssam_cplt_flush() - Flush the completion system. * @cplt: The completion system. * * Flush the completion system by waiting until all currently submitted work * items have been completed. * * Note: This function does not guarantee that all events will have been * handled once this call terminates. In case of a larger number of * to-be-completed events, the event queue work function may re-schedule its * work item, which this flush operation will ignore. * * This operation is only intended to, during normal operation prior to * shutdown, try to complete most events and requests to get them out of the * system while the system is still fully operational. It does not aim to * provide any guarantee that all of them have been handled. */ static void ssam_cplt_flush(struct ssam_cplt *cplt) { flush_workqueue(cplt->wq); } static void ssam_event_queue_work_fn(struct work_struct *work) { struct ssam_event_queue *queue; struct ssam_event_item *item; struct ssam_nf *nf; struct device *dev; unsigned int iterations = SSAM_CPLT_WQ_BATCH; queue = container_of(work, struct ssam_event_queue, work); nf = &queue->cplt->event.notif; dev = queue->cplt->dev; /* Limit number of processed events to avoid livelocking. */ do { item = ssam_event_queue_pop(queue); if (!item) return; ssam_nf_call(nf, dev, item->rqid, &item->event); ssam_event_item_free(item); } while (--iterations); if (!ssam_event_queue_is_empty(queue)) ssam_cplt_submit(queue->cplt, &queue->work); } /** * ssam_event_queue_init() - Initialize an event queue. * @cplt: The completion system on which the queue resides. * @evq: The event queue to initialize. */ static void ssam_event_queue_init(struct ssam_cplt *cplt, struct ssam_event_queue *evq) { evq->cplt = cplt; spin_lock_init(&evq->lock); INIT_LIST_HEAD(&evq->head); INIT_WORK(&evq->work, ssam_event_queue_work_fn); } /** * ssam_cplt_init() - Initialize completion system. * @cplt: The completion system to initialize. * @dev: The device used for logging. */ static int ssam_cplt_init(struct ssam_cplt *cplt, struct device *dev) { struct ssam_event_target *target; int status, c, i; cplt->dev = dev; cplt->wq = alloc_workqueue(SSAM_CPLT_WQ_NAME, WQ_UNBOUND | WQ_MEM_RECLAIM, 0); if (!cplt->wq) return -ENOMEM; for (c = 0; c < ARRAY_SIZE(cplt->event.target); c++) { target = &cplt->event.target[c]; for (i = 0; i < ARRAY_SIZE(target->queue); i++) ssam_event_queue_init(cplt, &target->queue[i]); } status = ssam_nf_init(&cplt->event.notif); if (status) destroy_workqueue(cplt->wq); return status; } /** * ssam_cplt_destroy() - Deinitialize the completion system. * @cplt: The completion system to deinitialize. * * Deinitialize the given completion system and ensure that all pending, i.e. * yet-to-be-completed, event items and requests have been handled. */ static void ssam_cplt_destroy(struct ssam_cplt *cplt) { /* * Note: destroy_workqueue ensures that all currently queued work will * be fully completed and the workqueue drained. This means that this * call will inherently also free any queued ssam_event_items, thus we * don't have to take care of that here explicitly. */ destroy_workqueue(cplt->wq); ssam_nf_destroy(&cplt->event.notif); } /* -- Main SSAM device structures. ------------------------------------------ */ /** * ssam_controller_device() - Get the &struct device associated with this * controller. * @c: The controller for which to get the device. * * Return: Returns the &struct device associated with this controller, * providing its lower-level transport. */ struct device *ssam_controller_device(struct ssam_controller *c) { return ssh_rtl_get_device(&c->rtl); } EXPORT_SYMBOL_GPL(ssam_controller_device); static void __ssam_controller_release(struct kref *kref) { struct ssam_controller *ctrl = to_ssam_controller(kref, kref); /* * The lock-call here is to satisfy lockdep. At this point we really * expect this to be the last remaining reference to the controller. * Anything else is a bug. */ ssam_controller_lock(ctrl); ssam_controller_destroy(ctrl); ssam_controller_unlock(ctrl); kfree(ctrl); } /** * ssam_controller_get() - Increment reference count of controller. * @c: The controller. * * Return: Returns the controller provided as input. */ struct ssam_controller *ssam_controller_get(struct ssam_controller *c) { if (c) kref_get(&c->kref); return c; } EXPORT_SYMBOL_GPL(ssam_controller_get); /** * ssam_controller_put() - Decrement reference count of controller. * @c: The controller. */ void ssam_controller_put(struct ssam_controller *c) { if (c) kref_put(&c->kref, __ssam_controller_release); } EXPORT_SYMBOL_GPL(ssam_controller_put); /** * ssam_controller_statelock() - Lock the controller against state transitions. * @c: The controller to lock. * * Lock the controller against state transitions. Holding this lock guarantees * that the controller will not transition between states, i.e. if the * controller is in state "started", when this lock has been acquired, it will * remain in this state at least until the lock has been released. * * Multiple clients may concurrently hold this lock. In other words: The * ``statelock`` functions represent the read-lock part of a r/w-semaphore. * Actions causing state transitions of the controller must be executed while * holding the write-part of this r/w-semaphore (see ssam_controller_lock() * and ssam_controller_unlock() for that). * * See ssam_controller_stateunlock() for the corresponding unlock function. */ void ssam_controller_statelock(struct ssam_controller *c) { down_read(&c->lock); } EXPORT_SYMBOL_GPL(ssam_controller_statelock); /** * ssam_controller_stateunlock() - Unlock controller state transitions. * @c: The controller to unlock. * * See ssam_controller_statelock() for the corresponding lock function. */ void ssam_controller_stateunlock(struct ssam_controller *c) { up_read(&c->lock); } EXPORT_SYMBOL_GPL(ssam_controller_stateunlock); /** * ssam_controller_lock() - Acquire the main controller lock. * @c: The controller to lock. * * This lock must be held for any state transitions, including transition to * suspend/resumed states and during shutdown. See ssam_controller_statelock() * for more details on controller locking. * * See ssam_controller_unlock() for the corresponding unlock function. */ void ssam_controller_lock(struct ssam_controller *c) { down_write(&c->lock); } /* * ssam_controller_unlock() - Release the main controller lock. * @c: The controller to unlock. * * See ssam_controller_lock() for the corresponding lock function. */ void ssam_controller_unlock(struct ssam_controller *c) { up_write(&c->lock); } static void ssam_handle_event(struct ssh_rtl *rtl, const struct ssh_command *cmd, const struct ssam_span *data) { struct ssam_controller *ctrl = to_ssam_controller(rtl, rtl); struct ssam_event_item *item; item = ssam_event_item_alloc(data->len, GFP_KERNEL); if (!item) return; item->rqid = get_unaligned_le16(&cmd->rqid); item->event.target_category = cmd->tc; item->event.target_id = cmd->sid; item->event.command_id = cmd->cid; item->event.instance_id = cmd->iid; memcpy(&item->event.data[0], data->ptr, data->len); if (WARN_ON(ssam_cplt_submit_event(&ctrl->cplt, item))) ssam_event_item_free(item); } static const struct ssh_rtl_ops ssam_rtl_ops = { .handle_event = ssam_handle_event, }; static bool ssam_notifier_is_empty(struct ssam_controller *ctrl); static void ssam_notifier_unregister_all(struct ssam_controller *ctrl); #define SSAM_SSH_DSM_REVISION 0 /* d5e383e1-d892-4a76-89fc-f6aaae7ed5b5 */ static const guid_t SSAM_SSH_DSM_GUID = GUID_INIT(0xd5e383e1, 0xd892, 0x4a76, 0x89, 0xfc, 0xf6, 0xaa, 0xae, 0x7e, 0xd5, 0xb5); enum ssh_dsm_fn { SSH_DSM_FN_SSH_POWER_PROFILE = 0x05, SSH_DSM_FN_SCREEN_ON_SLEEP_IDLE_TIMEOUT = 0x06, SSH_DSM_FN_SCREEN_OFF_SLEEP_IDLE_TIMEOUT = 0x07, SSH_DSM_FN_D3_CLOSES_HANDLE = 0x08, SSH_DSM_FN_SSH_BUFFER_SIZE = 0x09, }; static int ssam_dsm_get_functions(acpi_handle handle, u64 *funcs) { union acpi_object *obj; u64 mask = 0; int i; *funcs = 0; /* * The _DSM function is only present on newer models. It is not * present on 5th and 6th generation devices (i.e. up to and including * Surface Pro 6, Surface Laptop 2, Surface Book 2). * * If the _DSM is not present, indicate that no function is supported. * This will result in default values being set. */ if (!acpi_has_method(handle, "_DSM")) return 0; obj = acpi_evaluate_dsm_typed(handle, &SSAM_SSH_DSM_GUID, SSAM_SSH_DSM_REVISION, 0, NULL, ACPI_TYPE_BUFFER); if (!obj) return -EIO; for (i = 0; i < obj->buffer.length && i < 8; i++) mask |= (((u64)obj->buffer.pointer[i]) << (i * 8)); if (mask & BIT(0)) *funcs = mask; ACPI_FREE(obj); return 0; } static int ssam_dsm_load_u32(acpi_handle handle, u64 funcs, u64 func, u32 *ret) { union acpi_object *obj; u64 val; if (!(funcs & BIT_ULL(func))) return 0; /* Not supported, leave *ret at its default value */ obj = acpi_evaluate_dsm_typed(handle, &SSAM_SSH_DSM_GUID, SSAM_SSH_DSM_REVISION, func, NULL, ACPI_TYPE_INTEGER); if (!obj) return -EIO; val = obj->integer.value; ACPI_FREE(obj); if (val > U32_MAX) return -ERANGE; *ret = val; return 0; } /** * ssam_controller_caps_load_from_acpi() - Load controller capabilities from * ACPI _DSM. * @handle: The handle of the ACPI controller/SSH device. * @caps: Where to store the capabilities in. * * Initializes the given controller capabilities with default values, then * checks and, if the respective _DSM functions are available, loads the * actual capabilities from the _DSM. * * Return: Returns zero on success, a negative error code on failure. */ static int ssam_controller_caps_load_from_acpi(acpi_handle handle, struct ssam_controller_caps *caps) { u32 d3_closes_handle = false; u64 funcs; int status; /* Set defaults. */ caps->ssh_power_profile = U32_MAX; caps->screen_on_sleep_idle_timeout = U32_MAX; caps->screen_off_sleep_idle_timeout = U32_MAX; caps->d3_closes_handle = false; caps->ssh_buffer_size = U32_MAX; /* Pre-load supported DSM functions. */ status = ssam_dsm_get_functions(handle, &funcs); if (status) return status; /* Load actual values from ACPI, if present. */ status = ssam_dsm_load_u32(handle, funcs, SSH_DSM_FN_SSH_POWER_PROFILE, &caps->ssh_power_profile); if (status) return status; status = ssam_dsm_load_u32(handle, funcs, SSH_DSM_FN_SCREEN_ON_SLEEP_IDLE_TIMEOUT, &caps->screen_on_sleep_idle_timeout); if (status) return status; status = ssam_dsm_load_u32(handle, funcs, SSH_DSM_FN_SCREEN_OFF_SLEEP_IDLE_TIMEOUT, &caps->screen_off_sleep_idle_timeout); if (status) return status; status = ssam_dsm_load_u32(handle, funcs, SSH_DSM_FN_D3_CLOSES_HANDLE, &d3_closes_handle); if (status) return status; caps->d3_closes_handle = !!d3_closes_handle; status = ssam_dsm_load_u32(handle, funcs, SSH_DSM_FN_SSH_BUFFER_SIZE, &caps->ssh_buffer_size); if (status) return status; return 0; } /** * ssam_controller_init() - Initialize SSAM controller. * @ctrl: The controller to initialize. * @serdev: The serial device representing the underlying data transport. * * Initializes the given controller. Does neither start receiver nor * transmitter threads. After this call, the controller has to be hooked up to * the serdev core separately via &struct serdev_device_ops, relaying calls to * ssam_controller_receive_buf() and ssam_controller_write_wakeup(). Once the * controller has been hooked up, transmitter and receiver threads may be * started via ssam_controller_start(). These setup steps need to be completed * before controller can be used for requests. */ int ssam_controller_init(struct ssam_controller *ctrl, struct serdev_device *serdev) { acpi_handle handle = ACPI_HANDLE(&serdev->dev); int status; init_rwsem(&ctrl->lock); kref_init(&ctrl->kref); status = ssam_controller_caps_load_from_acpi(handle, &ctrl->caps); if (status) return status; dev_dbg(&serdev->dev, "device capabilities:\n" " ssh_power_profile: %u\n" " ssh_buffer_size: %u\n" " screen_on_sleep_idle_timeout: %u\n" " screen_off_sleep_idle_timeout: %u\n" " d3_closes_handle: %u\n", ctrl->caps.ssh_power_profile, ctrl->caps.ssh_buffer_size, ctrl->caps.screen_on_sleep_idle_timeout, ctrl->caps.screen_off_sleep_idle_timeout, ctrl->caps.d3_closes_handle); ssh_seq_reset(&ctrl->counter.seq); ssh_rqid_reset(&ctrl->counter.rqid); /* Initialize event/request completion system. */ status = ssam_cplt_init(&ctrl->cplt, &serdev->dev); if (status) return status; /* Initialize request and packet transport layers. */ status = ssh_rtl_init(&ctrl->rtl, serdev, &ssam_rtl_ops); if (status) { ssam_cplt_destroy(&ctrl->cplt); return status; } /* * Set state via write_once even though we expect to be in an * exclusive context, due to smoke-testing in * ssam_request_sync_submit(). */ WRITE_ONCE(ctrl->state, SSAM_CONTROLLER_INITIALIZED); return 0; } /** * ssam_controller_start() - Start the receiver and transmitter threads of the * controller. * @ctrl: The controller. * * Note: When this function is called, the controller should be properly * hooked up to the serdev core via &struct serdev_device_ops. Please refer * to ssam_controller_init() for more details on controller initialization. * * This function must be called with the main controller lock held (i.e. by * calling ssam_controller_lock()). */ int ssam_controller_start(struct ssam_controller *ctrl) { int status; lockdep_assert_held_write(&ctrl->lock); if (ctrl->state != SSAM_CONTROLLER_INITIALIZED) return -EINVAL; status = ssh_rtl_start(&ctrl->rtl); if (status) return status; /* * Set state via write_once even though we expect to be locked/in an * exclusive context, due to smoke-testing in * ssam_request_sync_submit(). */ WRITE_ONCE(ctrl->state, SSAM_CONTROLLER_STARTED); return 0; } /* * SSAM_CTRL_SHUTDOWN_FLUSH_TIMEOUT - Timeout for flushing requests during * shutdown. * * Chosen to be larger than one full request timeout, including packets timing * out. This value should give ample time to complete any outstanding requests * during normal operation and account for the odd package timeout. */ #define SSAM_CTRL_SHUTDOWN_FLUSH_TIMEOUT msecs_to_jiffies(5000) /** * ssam_controller_shutdown() - Shut down the controller. * @ctrl: The controller. * * Shuts down the controller by flushing all pending requests and stopping the * transmitter and receiver threads. All requests submitted after this call * will fail with %-ESHUTDOWN. While it is discouraged to do so, this function * is safe to use in parallel with ongoing request submission. * * In the course of this shutdown procedure, all currently registered * notifiers will be unregistered. It is, however, strongly recommended to not * rely on this behavior, and instead the party registering the notifier * should unregister it before the controller gets shut down, e.g. via the * SSAM bus which guarantees client devices to be removed before a shutdown. * * Note that events may still be pending after this call, but, due to the * notifiers being unregistered, these events will be dropped when the * controller is subsequently destroyed via ssam_controller_destroy(). * * This function must be called with the main controller lock held (i.e. by * calling ssam_controller_lock()). */ void ssam_controller_shutdown(struct ssam_controller *ctrl) { enum ssam_controller_state s = ctrl->state; int status; lockdep_assert_held_write(&ctrl->lock); if (s == SSAM_CONTROLLER_UNINITIALIZED || s == SSAM_CONTROLLER_STOPPED) return; /* * Try to flush pending events and requests while everything still * works. Note: There may still be packets and/or requests in the * system after this call (e.g. via control packets submitted by the * packet transport layer or flush timeout / failure, ...). Those will * be handled with the ssh_rtl_shutdown() call below. */ status = ssh_rtl_flush(&ctrl->rtl, SSAM_CTRL_SHUTDOWN_FLUSH_TIMEOUT); if (status) { ssam_err(ctrl, "failed to flush request transport layer: %d\n", status); } /* Try to flush all currently completing requests and events. */ ssam_cplt_flush(&ctrl->cplt); /* * We expect all notifiers to have been removed by the respective client * driver that set them up at this point. If this warning occurs, some * client driver has not done that... */ WARN_ON(!ssam_notifier_is_empty(ctrl)); /* * Nevertheless, we should still take care of drivers that don't behave * well. Thus disable all enabled events, unregister all notifiers. */ ssam_notifier_unregister_all(ctrl); /* * Cancel remaining requests. Ensure no new ones can be queued and stop * threads. */ ssh_rtl_shutdown(&ctrl->rtl); /* * Set state via write_once even though we expect to be locked/in an * exclusive context, due to smoke-testing in * ssam_request_sync_submit(). */ WRITE_ONCE(ctrl->state, SSAM_CONTROLLER_STOPPED); ctrl->rtl.ptl.serdev = NULL; } /** * ssam_controller_destroy() - Destroy the controller and free its resources. * @ctrl: The controller. * * Ensures that all resources associated with the controller get freed. This * function should only be called after the controller has been stopped via * ssam_controller_shutdown(). In general, this function should not be called * directly. The only valid place to call this function directly is during * initialization, before the controller has been fully initialized and passed * to other processes. This function is called automatically when the * reference count of the controller reaches zero. * * This function must be called with the main controller lock held (i.e. by * calling ssam_controller_lock()). */ void ssam_controller_destroy(struct ssam_controller *ctrl) { lockdep_assert_held_write(&ctrl->lock); if (ctrl->state == SSAM_CONTROLLER_UNINITIALIZED) return; WARN_ON(ctrl->state != SSAM_CONTROLLER_STOPPED); /* * Note: New events could still have been received after the previous * flush in ssam_controller_shutdown, before the request transport layer * has been shut down. At this point, after the shutdown, we can be sure * that no new events will be queued. The call to ssam_cplt_destroy will * ensure that those remaining are being completed and freed. */ /* Actually free resources. */ ssam_cplt_destroy(&ctrl->cplt); ssh_rtl_destroy(&ctrl->rtl); /* * Set state via write_once even though we expect to be locked/in an * exclusive context, due to smoke-testing in * ssam_request_sync_submit(). */ WRITE_ONCE(ctrl->state, SSAM_CONTROLLER_UNINITIALIZED); } /** * ssam_controller_suspend() - Suspend the controller. * @ctrl: The controller to suspend. * * Marks the controller as suspended. Note that display-off and D0-exit * notifications have to be sent manually before transitioning the controller * into the suspended state via this function. * * See ssam_controller_resume() for the corresponding resume function. * * Return: Returns %-EINVAL if the controller is currently not in the * "started" state. */ int ssam_controller_suspend(struct ssam_controller *ctrl) { ssam_controller_lock(ctrl); if (ctrl->state != SSAM_CONTROLLER_STARTED) { ssam_controller_unlock(ctrl); return -EINVAL; } ssam_dbg(ctrl, "pm: suspending controller\n"); /* * Set state via write_once even though we're locked, due to * smoke-testing in ssam_request_sync_submit(). */ WRITE_ONCE(ctrl->state, SSAM_CONTROLLER_SUSPENDED); ssam_controller_unlock(ctrl); return 0; } /** * ssam_controller_resume() - Resume the controller from suspend. * @ctrl: The controller to resume. * * Resume the controller from the suspended state it was put into via * ssam_controller_suspend(). This function does not issue display-on and * D0-entry notifications. If required, those have to be sent manually after * this call. * * Return: Returns %-EINVAL if the controller is currently not suspended. */ int ssam_controller_resume(struct ssam_controller *ctrl) { ssam_controller_lock(ctrl); if (ctrl->state != SSAM_CONTROLLER_SUSPENDED) { ssam_controller_unlock(ctrl); return -EINVAL; } ssam_dbg(ctrl, "pm: resuming controller\n"); /* * Set state via write_once even though we're locked, due to * smoke-testing in ssam_request_sync_submit(). */ WRITE_ONCE(ctrl->state, SSAM_CONTROLLER_STARTED); ssam_controller_unlock(ctrl); return 0; } /* -- Top-level request interface ------------------------------------------- */ /** * ssam_request_write_data() - Construct and write SAM request message to * buffer. * @buf: The buffer to write the data to. * @ctrl: The controller via which the request will be sent. * @spec: The request data and specification. * * Constructs a SAM/SSH request message and writes it to the provided buffer. * The request and transport counters, specifically RQID and SEQ, will be set * in this call. These counters are obtained from the controller. It is thus * only valid to send the resulting message via the controller specified here. * * For calculation of the required buffer size, refer to the * SSH_COMMAND_MESSAGE_LENGTH() macro. * * Return: Returns the number of bytes used in the buffer on success. Returns * %-EINVAL if the payload length provided in the request specification is too * large (larger than %SSH_COMMAND_MAX_PAYLOAD_SIZE) or if the provided buffer * is too small. */ ssize_t ssam_request_write_data(struct ssam_span *buf, struct ssam_controller *ctrl, const struct ssam_request *spec) { struct msgbuf msgb; u16 rqid; u8 seq; if (spec->length > SSH_COMMAND_MAX_PAYLOAD_SIZE) return -EINVAL; if (SSH_COMMAND_MESSAGE_LENGTH(spec->length) > buf->len) return -EINVAL; msgb_init(&msgb, buf->ptr, buf->len); seq = ssh_seq_next(&ctrl->counter.seq); rqid = ssh_rqid_next(&ctrl->counter.rqid); msgb_push_cmd(&msgb, seq, rqid, spec); return msgb_bytes_used(&msgb); } EXPORT_SYMBOL_GPL(ssam_request_write_data); static void ssam_request_sync_complete(struct ssh_request *rqst, const struct ssh_command *cmd, const struct ssam_span *data, int status) { struct ssh_rtl *rtl = ssh_request_rtl(rqst); struct ssam_request_sync *r; r = container_of(rqst, struct ssam_request_sync, base); r->status = status; if (r->resp) r->resp->length = 0; if (status) { rtl_dbg_cond(rtl, "rsp: request failed: %d\n", status); return; } if (!data) /* Handle requests without a response. */ return; if (!r->resp || !r->resp->pointer) { if (data->len) rtl_warn(rtl, "rsp: no response buffer provided, dropping data\n"); return; } if (data->len > r->resp->capacity) { rtl_err(rtl, "rsp: response buffer too small, capacity: %zu bytes, got: %zu bytes\n", r->resp->capacity, data->len); r->status = -ENOSPC; return; } r->resp->length = data->len; memcpy(r->resp->pointer, data->ptr, data->len); } static void ssam_request_sync_release(struct ssh_request *rqst) { complete_all(&container_of(rqst, struct ssam_request_sync, base)->comp); } static const struct ssh_request_ops ssam_request_sync_ops = { .release = ssam_request_sync_release, .complete = ssam_request_sync_complete, }; /** * ssam_request_sync_alloc() - Allocate a synchronous request. * @payload_len: The length of the request payload. * @flags: Flags used for allocation. * @rqst: Where to store the pointer to the allocated request. * @buffer: Where to store the buffer descriptor for the message buffer of * the request. * * Allocates a synchronous request with corresponding message buffer. The * request still needs to be initialized ssam_request_sync_init() before * it can be submitted, and the message buffer data must still be set to the * returned buffer via ssam_request_sync_set_data() after it has been filled, * if need be with adjusted message length. * * After use, the request and its corresponding message buffer should be freed * via ssam_request_sync_free(). The buffer must not be freed separately. * * Return: Returns zero on success, %-ENOMEM if the request could not be * allocated. */ int ssam_request_sync_alloc(size_t payload_len, gfp_t flags, struct ssam_request_sync **rqst, struct ssam_span *buffer) { size_t msglen = SSH_COMMAND_MESSAGE_LENGTH(payload_len); *rqst = kzalloc(sizeof(**rqst) + msglen, flags); if (!*rqst) return -ENOMEM; buffer->ptr = (u8 *)(*rqst + 1); buffer->len = msglen; return 0; } EXPORT_SYMBOL_GPL(ssam_request_sync_alloc); /** * ssam_request_sync_free() - Free a synchronous request. * @rqst: The request to be freed. * * Free a synchronous request and its corresponding buffer allocated with * ssam_request_sync_alloc(). Do not use for requests allocated on the stack * or via any other function. * * Warning: The caller must ensure that the request is not in use any more. * I.e. the caller must ensure that it has the only reference to the request * and the request is not currently pending. This means that the caller has * either never submitted the request, request submission has failed, or the * caller has waited until the submitted request has been completed via * ssam_request_sync_wait(). */ void ssam_request_sync_free(struct ssam_request_sync *rqst) { kfree(rqst); } EXPORT_SYMBOL_GPL(ssam_request_sync_free); /** * ssam_request_sync_init() - Initialize a synchronous request struct. * @rqst: The request to initialize. * @flags: The request flags. * * Initializes the given request struct. Does not initialize the request * message data. This has to be done explicitly after this call via * ssam_request_sync_set_data() and the actual message data has to be written * via ssam_request_write_data(). * * Return: Returns zero on success or %-EINVAL if the given flags are invalid. */ int ssam_request_sync_init(struct ssam_request_sync *rqst, enum ssam_request_flags flags) { int status; status = ssh_request_init(&rqst->base, flags, &ssam_request_sync_ops); if (status) return status; init_completion(&rqst->comp); rqst->resp = NULL; rqst->status = 0; return 0; } EXPORT_SYMBOL_GPL(ssam_request_sync_init); /** * ssam_request_sync_submit() - Submit a synchronous request. * @ctrl: The controller with which to submit the request. * @rqst: The request to submit. * * Submit a synchronous request. The request has to be initialized and * properly set up, including response buffer (may be %NULL if no response is * expected) and command message data. This function does not wait for the * request to be completed. * * If this function succeeds, ssam_request_sync_wait() must be used to ensure * that the request has been completed before the response data can be * accessed and/or the request can be freed. On failure, the request may * immediately be freed. * * This function may only be used if the controller is active, i.e. has been * initialized and not suspended. */ int ssam_request_sync_submit(struct ssam_controller *ctrl, struct ssam_request_sync *rqst) { int status; /* * This is only a superficial check. In general, the caller needs to * ensure that the controller is initialized and is not (and does not * get) suspended during use, i.e. until the request has been completed * (if _absolutely_ necessary, by use of ssam_controller_statelock/ * ssam_controller_stateunlock, but something like ssam_client_link * should be preferred as this needs to last until the request has been * completed). * * Note that it is actually safe to use this function while the * controller is in the process of being shut down (as ssh_rtl_submit * is safe with regards to this), but it is generally discouraged to do * so. */ if (WARN_ON(READ_ONCE(ctrl->state) != SSAM_CONTROLLER_STARTED)) { ssh_request_put(&rqst->base); return -ENODEV; } status = ssh_rtl_submit(&ctrl->rtl, &rqst->base); ssh_request_put(&rqst->base); return status; } EXPORT_SYMBOL_GPL(ssam_request_sync_submit); /** * ssam_request_do_sync() - Execute a synchronous request. * @ctrl: The controller via which the request will be submitted. * @spec: The request specification and payload. * @rsp: The response buffer. * * Allocates a synchronous request with its message data buffer on the heap * via ssam_request_sync_alloc(), fully initializes it via the provided * request specification, submits it, and finally waits for its completion * before freeing it and returning its status. * * Return: Returns the status of the request or any failure during setup. */ int ssam_request_do_sync(struct ssam_controller *ctrl, const struct ssam_request *spec, struct ssam_response *rsp) { struct ssam_request_sync *rqst; struct ssam_span buf; ssize_t len; int status; status = ssam_request_sync_alloc(spec->length, GFP_KERNEL, &rqst, &buf); if (status) return status; status = ssam_request_sync_init(rqst, spec->flags); if (status) { ssam_request_sync_free(rqst); return status; } ssam_request_sync_set_resp(rqst, rsp); len = ssam_request_write_data(&buf, ctrl, spec); if (len < 0) { ssam_request_sync_free(rqst); return len; } ssam_request_sync_set_data(rqst, buf.ptr, len); status = ssam_request_sync_submit(ctrl, rqst); if (!status) status = ssam_request_sync_wait(rqst); ssam_request_sync_free(rqst); return status; } EXPORT_SYMBOL_GPL(ssam_request_do_sync); /** * ssam_request_do_sync_with_buffer() - Execute a synchronous request with the * provided buffer as back-end for the message buffer. * @ctrl: The controller via which the request will be submitted. * @spec: The request specification and payload. * @rsp: The response buffer. * @buf: The buffer for the request message data. * * Allocates a synchronous request struct on the stack, fully initializes it * using the provided buffer as message data buffer, submits it, and then * waits for its completion before returning its status. The * SSH_COMMAND_MESSAGE_LENGTH() macro can be used to compute the required * message buffer size. * * This function does essentially the same as ssam_request_do_sync(), but * instead of dynamically allocating the request and message data buffer, it * uses the provided message data buffer and stores the (small) request struct * on the heap. * * Return: Returns the status of the request or any failure during setup. */ int ssam_request_do_sync_with_buffer(struct ssam_controller *ctrl, const struct ssam_request *spec, struct ssam_response *rsp, struct ssam_span *buf) { struct ssam_request_sync rqst; ssize_t len; int status; status = ssam_request_sync_init(&rqst, spec->flags); if (status) return status; ssam_request_sync_set_resp(&rqst, rsp); len = ssam_request_write_data(buf, ctrl, spec); if (len < 0) return len; ssam_request_sync_set_data(&rqst, buf->ptr, len); status = ssam_request_sync_submit(ctrl, &rqst); if (!status) status = ssam_request_sync_wait(&rqst); return status; } EXPORT_SYMBOL_GPL(ssam_request_do_sync_with_buffer); /* -- Internal SAM requests. ------------------------------------------------ */ SSAM_DEFINE_SYNC_REQUEST_R(ssam_ssh_get_firmware_version, __le32, { .target_category = SSAM_SSH_TC_SAM, .target_id = SSAM_SSH_TID_SAM, .command_id = 0x13, .instance_id = 0x00, }); SSAM_DEFINE_SYNC_REQUEST_R(ssam_ssh_notif_display_off, u8, { .target_category = SSAM_SSH_TC_SAM, .target_id = SSAM_SSH_TID_SAM, .command_id = 0x15, .instance_id = 0x00, }); SSAM_DEFINE_SYNC_REQUEST_R(ssam_ssh_notif_display_on, u8, { .target_category = SSAM_SSH_TC_SAM, .target_id = SSAM_SSH_TID_SAM, .command_id = 0x16, .instance_id = 0x00, }); SSAM_DEFINE_SYNC_REQUEST_R(ssam_ssh_notif_d0_exit, u8, { .target_category = SSAM_SSH_TC_SAM, .target_id = SSAM_SSH_TID_SAM, .command_id = 0x33, .instance_id = 0x00, }); SSAM_DEFINE_SYNC_REQUEST_R(ssam_ssh_notif_d0_entry, u8, { .target_category = SSAM_SSH_TC_SAM, .target_id = SSAM_SSH_TID_SAM, .command_id = 0x34, .instance_id = 0x00, }); /** * struct ssh_notification_params - Command payload to enable/disable SSH * notifications. * @target_category: The target category for which notifications should be * enabled/disabled. * @flags: Flags determining how notifications are being sent. * @request_id: The request ID that is used to send these notifications. * @instance_id: The specific instance in the given target category for * which notifications should be enabled. */ struct ssh_notification_params { u8 target_category; u8 flags; __le16 request_id; u8 instance_id; } __packed; static_assert(sizeof(struct ssh_notification_params) == 5); static int __ssam_ssh_event_request(struct ssam_controller *ctrl, struct ssam_event_registry reg, u8 cid, struct ssam_event_id id, u8 flags) { struct ssh_notification_params params; struct ssam_request rqst; struct ssam_response result; int status; u16 rqid = ssh_tc_to_rqid(id.target_category); u8 buf = 0; /* Only allow RQIDs that lie within the event spectrum. */ if (!ssh_rqid_is_event(rqid)) return -EINVAL; params.target_category = id.target_category; params.instance_id = id.instance; params.flags = flags; put_unaligned_le16(rqid, ¶ms.request_id); rqst.target_category = reg.target_category; rqst.target_id = reg.target_id; rqst.command_id = cid; rqst.instance_id = 0x00; rqst.flags = SSAM_REQUEST_HAS_RESPONSE; rqst.length = sizeof(params); rqst.payload = (u8 *)¶ms; result.capacity = sizeof(buf); result.length = 0; result.pointer = &buf; status = ssam_retry(ssam_request_do_sync_onstack, ctrl, &rqst, &result, sizeof(params)); return status < 0 ? status : buf; } /** * ssam_ssh_event_enable() - Enable SSH event. * @ctrl: The controller for which to enable the event. * @reg: The event registry describing what request to use for enabling and * disabling the event. * @id: The event identifier. * @flags: The event flags. * * Enables the specified event on the EC. This function does not manage * reference counting of enabled events and is basically only a wrapper for * the raw EC request. If the specified event is already enabled, the EC will * ignore this request. * * Return: Returns the status of the executed SAM request (zero on success and * negative on direct failure) or %-EPROTO if the request response indicates a * failure. */ static int ssam_ssh_event_enable(struct ssam_controller *ctrl, struct ssam_event_registry reg, struct ssam_event_id id, u8 flags) { int status; status = __ssam_ssh_event_request(ctrl, reg, reg.cid_enable, id, flags); if (status < 0 && status != -EINVAL) { ssam_err(ctrl, "failed to enable event source (tc: %#04x, iid: %#04x, reg: %#04x)\n", id.target_category, id.instance, reg.target_category); } if (status > 0) { ssam_err(ctrl, "unexpected result while enabling event source: %#04x (tc: %#04x, iid: %#04x, reg: %#04x)\n", status, id.target_category, id.instance, reg.target_category); return -EPROTO; } return status; } /** * ssam_ssh_event_disable() - Disable SSH event. * @ctrl: The controller for which to disable the event. * @reg: The event registry describing what request to use for enabling and * disabling the event (must be same as used when enabling the event). * @id: The event identifier. * @flags: The event flags (likely ignored for disabling of events). * * Disables the specified event on the EC. This function does not manage * reference counting of enabled events and is basically only a wrapper for * the raw EC request. If the specified event is already disabled, the EC will * ignore this request. * * Return: Returns the status of the executed SAM request (zero on success and * negative on direct failure) or %-EPROTO if the request response indicates a * failure. */ static int ssam_ssh_event_disable(struct ssam_controller *ctrl, struct ssam_event_registry reg, struct ssam_event_id id, u8 flags) { int status; status = __ssam_ssh_event_request(ctrl, reg, reg.cid_disable, id, flags); if (status < 0 && status != -EINVAL) { ssam_err(ctrl, "failed to disable event source (tc: %#04x, iid: %#04x, reg: %#04x)\n", id.target_category, id.instance, reg.target_category); } if (status > 0) { ssam_err(ctrl, "unexpected result while disabling event source: %#04x (tc: %#04x, iid: %#04x, reg: %#04x)\n", status, id.target_category, id.instance, reg.target_category); return -EPROTO; } return status; } /* -- Wrappers for internal SAM requests. ----------------------------------- */ /** * ssam_get_firmware_version() - Get the SAM/EC firmware version. * @ctrl: The controller. * @version: Where to store the version number. * * Return: Returns zero on success or the status of the executed SAM request * if that request failed. */ int ssam_get_firmware_version(struct ssam_controller *ctrl, u32 *version) { __le32 __version; int status; status = ssam_retry(ssam_ssh_get_firmware_version, ctrl, &__version); if (status) return status; *version = le32_to_cpu(__version); return 0; } /** * ssam_ctrl_notif_display_off() - Notify EC that the display has been turned * off. * @ctrl: The controller. * * Notify the EC that the display has been turned off and the driver may enter * a lower-power state. This will prevent events from being sent directly. * Rather, the EC signals an event by pulling the wakeup GPIO high for as long * as there are pending events. The events then need to be manually released, * one by one, via the GPIO callback request. All pending events accumulated * during this state can also be released by issuing the display-on * notification, e.g. via ssam_ctrl_notif_display_on(), which will also reset * the GPIO. * * On some devices, specifically ones with an integrated keyboard, the keyboard * backlight will be turned off by this call. * * This function will only send the display-off notification command if * display notifications are supported by the EC. Currently all known devices * support these notifications. * * Use ssam_ctrl_notif_display_on() to reverse the effects of this function. * * Return: Returns zero on success or if no request has been executed, the * status of the executed SAM request if that request failed, or %-EPROTO if * an unexpected response has been received. */ int ssam_ctrl_notif_display_off(struct ssam_controller *ctrl) { int status; u8 response; ssam_dbg(ctrl, "pm: notifying display off\n"); status = ssam_retry(ssam_ssh_notif_display_off, ctrl, &response); if (status) return status; if (response != 0) { ssam_err(ctrl, "unexpected response from display-off notification: %#04x\n", response); return -EPROTO; } return 0; } /** * ssam_ctrl_notif_display_on() - Notify EC that the display has been turned on. * @ctrl: The controller. * * Notify the EC that the display has been turned back on and the driver has * exited its lower-power state. This notification is the counterpart to the * display-off notification sent via ssam_ctrl_notif_display_off() and will * reverse its effects, including resetting events to their default behavior. * * This function will only send the display-on notification command if display * notifications are supported by the EC. Currently all known devices support * these notifications. * * See ssam_ctrl_notif_display_off() for more details. * * Return: Returns zero on success or if no request has been executed, the * status of the executed SAM request if that request failed, or %-EPROTO if * an unexpected response has been received. */ int ssam_ctrl_notif_display_on(struct ssam_controller *ctrl) { int status; u8 response; ssam_dbg(ctrl, "pm: notifying display on\n"); status = ssam_retry(ssam_ssh_notif_display_on, ctrl, &response); if (status) return status; if (response != 0) { ssam_err(ctrl, "unexpected response from display-on notification: %#04x\n", response); return -EPROTO; } return 0; } /** * ssam_ctrl_notif_d0_exit() - Notify EC that the driver/device exits the D0 * power state. * @ctrl: The controller * * Notifies the EC that the driver prepares to exit the D0 power state in * favor of a lower-power state. Exact effects of this function related to the * EC are currently unknown. * * This function will only send the D0-exit notification command if D0-state * notifications are supported by the EC. Only newer Surface generations * support these notifications. * * Use ssam_ctrl_notif_d0_entry() to reverse the effects of this function. * * Return: Returns zero on success or if no request has been executed, the * status of the executed SAM request if that request failed, or %-EPROTO if * an unexpected response has been received. */ int ssam_ctrl_notif_d0_exit(struct ssam_controller *ctrl) { int status; u8 response; if (!ctrl->caps.d3_closes_handle) return 0; ssam_dbg(ctrl, "pm: notifying D0 exit\n"); status = ssam_retry(ssam_ssh_notif_d0_exit, ctrl, &response); if (status) return status; if (response != 0) { ssam_err(ctrl, "unexpected response from D0-exit notification: %#04x\n", response); return -EPROTO; } return 0; } /** * ssam_ctrl_notif_d0_entry() - Notify EC that the driver/device enters the D0 * power state. * @ctrl: The controller * * Notifies the EC that the driver has exited a lower-power state and entered * the D0 power state. Exact effects of this function related to the EC are * currently unknown. * * This function will only send the D0-entry notification command if D0-state * notifications are supported by the EC. Only newer Surface generations * support these notifications. * * See ssam_ctrl_notif_d0_exit() for more details. * * Return: Returns zero on success or if no request has been executed, the * status of the executed SAM request if that request failed, or %-EPROTO if * an unexpected response has been received. */ int ssam_ctrl_notif_d0_entry(struct ssam_controller *ctrl) { int status; u8 response; if (!ctrl->caps.d3_closes_handle) return 0; ssam_dbg(ctrl, "pm: notifying D0 entry\n"); status = ssam_retry(ssam_ssh_notif_d0_entry, ctrl, &response); if (status) return status; if (response != 0) { ssam_err(ctrl, "unexpected response from D0-entry notification: %#04x\n", response); return -EPROTO; } return 0; } /* -- Top-level event registry interface. ----------------------------------- */ /** * ssam_nf_refcount_enable() - Enable event for reference count entry if it has * not already been enabled. * @ctrl: The controller to enable the event on. * @entry: The reference count entry for the event to be enabled. * @flags: The flags used for enabling the event on the EC. * * Enable the event associated with the given reference count entry if the * reference count equals one, i.e. the event has not previously been enabled. * If the event has already been enabled (i.e. reference count not equal to * one), check that the flags used for enabling match and warn about this if * they do not. * * This does not modify the reference count itself, which is done with * ssam_nf_refcount_inc() / ssam_nf_refcount_dec(). * * Note: ``nf->lock`` must be held when calling this function. * * Return: Returns zero on success. If the event is enabled by this call, * returns the status of the event-enable EC command. */ static int ssam_nf_refcount_enable(struct ssam_controller *ctrl, struct ssam_nf_refcount_entry *entry, u8 flags) { const struct ssam_event_registry reg = entry->key.reg; const struct ssam_event_id id = entry->key.id; struct ssam_nf *nf = &ctrl->cplt.event.notif; int status; lockdep_assert_held(&nf->lock); ssam_dbg(ctrl, "enabling event (reg: %#04x, tc: %#04x, iid: %#04x, rc: %d)\n", reg.target_category, id.target_category, id.instance, entry->refcount); if (entry->refcount == 1) { status = ssam_ssh_event_enable(ctrl, reg, id, flags); if (status) return status; entry->flags = flags; } else if (entry->flags != flags) { ssam_warn(ctrl, "inconsistent flags when enabling event: got %#04x, expected %#04x (reg: %#04x, tc: %#04x, iid: %#04x)\n", flags, entry->flags, reg.target_category, id.target_category, id.instance); } return 0; } /** * ssam_nf_refcount_disable_free() - Disable event for reference count entry if * it is no longer in use and free the corresponding entry. * @ctrl: The controller to disable the event on. * @entry: The reference count entry for the event to be disabled. * @flags: The flags used for enabling the event on the EC. * @ec: Flag specifying if the event should actually be disabled on the EC. * * If ``ec`` equals ``true`` and the reference count equals zero (i.e. the * event is no longer requested by any client), the specified event will be * disabled on the EC via the corresponding request. * * If ``ec`` equals ``false``, no request will be sent to the EC and the event * can be considered in a detached state (i.e. no longer used but still * enabled). Disabling an event via this method may be required for * hot-removable devices, where event disable requests may time out after the * device has been physically removed. * * In both cases, if the reference count equals zero, the corresponding * reference count entry will be freed. The reference count entry must not be * used any more after a call to this function. * * Also checks if the flags used for disabling the event match the flags used * for enabling the event and warns if they do not (regardless of reference * count). * * This does not modify the reference count itself, which is done with * ssam_nf_refcount_inc() / ssam_nf_refcount_dec(). * * Note: ``nf->lock`` must be held when calling this function. * * Return: Returns zero on success. If the event is disabled by this call, * returns the status of the event-enable EC command. */ static int ssam_nf_refcount_disable_free(struct ssam_controller *ctrl, struct ssam_nf_refcount_entry *entry, u8 flags, bool ec) { const struct ssam_event_registry reg = entry->key.reg; const struct ssam_event_id id = entry->key.id; struct ssam_nf *nf = &ctrl->cplt.event.notif; int status = 0; lockdep_assert_held(&nf->lock); ssam_dbg(ctrl, "%s event (reg: %#04x, tc: %#04x, iid: %#04x, rc: %d)\n", ec ? "disabling" : "detaching", reg.target_category, id.target_category, id.instance, entry->refcount); if (entry->flags != flags) { ssam_warn(ctrl, "inconsistent flags when disabling event: got %#04x, expected %#04x (reg: %#04x, tc: %#04x, iid: %#04x)\n", flags, entry->flags, reg.target_category, id.target_category, id.instance); } if (ec && entry->refcount == 0) { status = ssam_ssh_event_disable(ctrl, reg, id, flags); kfree(entry); } return status; } /** * ssam_notifier_register() - Register an event notifier. * @ctrl: The controller to register the notifier on. * @n: The event notifier to register. * * Register an event notifier. Increment the usage counter of the associated * SAM event if the notifier is not marked as an observer. If the event is not * marked as an observer and is currently not enabled, it will be enabled * during this call. If the notifier is marked as an observer, no attempt will * be made at enabling any event and no reference count will be modified. * * Notifiers marked as observers do not need to be associated with one specific * event, i.e. as long as no event matching is performed, only the event target * category needs to be set. * * Return: Returns zero on success, %-ENOSPC if there have already been * %INT_MAX notifiers for the event ID/type associated with the notifier block * registered, %-ENOMEM if the corresponding event entry could not be * allocated. If this is the first time that a notifier block is registered * for the specific associated event, returns the status of the event-enable * EC-command. */ int ssam_notifier_register(struct ssam_controller *ctrl, struct ssam_event_notifier *n) { u16 rqid = ssh_tc_to_rqid(n->event.id.target_category); struct ssam_nf_refcount_entry *entry = NULL; struct ssam_nf_head *nf_head; struct ssam_nf *nf; int status; if (!ssh_rqid_is_event(rqid)) return -EINVAL; nf = &ctrl->cplt.event.notif; nf_head = &nf->head[ssh_rqid_to_event(rqid)]; mutex_lock(&nf->lock); if (!(n->flags & SSAM_EVENT_NOTIFIER_OBSERVER)) { entry = ssam_nf_refcount_inc(nf, n->event.reg, n->event.id); if (IS_ERR(entry)) { mutex_unlock(&nf->lock); return PTR_ERR(entry); } } status = ssam_nfblk_insert(nf_head, &n->base); if (status) { if (entry) ssam_nf_refcount_dec_free(nf, n->event.reg, n->event.id); mutex_unlock(&nf->lock); return status; } if (entry) { status = ssam_nf_refcount_enable(ctrl, entry, n->event.flags); if (status) { ssam_nfblk_remove(&n->base); ssam_nf_refcount_dec_free(nf, n->event.reg, n->event.id); mutex_unlock(&nf->lock); synchronize_srcu(&nf_head->srcu); return status; } } mutex_unlock(&nf->lock); return 0; } EXPORT_SYMBOL_GPL(ssam_notifier_register); /** * __ssam_notifier_unregister() - Unregister an event notifier. * @ctrl: The controller the notifier has been registered on. * @n: The event notifier to unregister. * @disable: Whether to disable the corresponding event on the EC. * * Unregister an event notifier. Decrement the usage counter of the associated * SAM event if the notifier is not marked as an observer. If the usage counter * reaches zero and ``disable`` equals ``true``, the event will be disabled. * * Useful for hot-removable devices, where communication may fail once the * device has been physically removed. In that case, specifying ``disable`` as * ``false`` avoids communication with the EC. * * Return: Returns zero on success, %-ENOENT if the given notifier block has * not been registered on the controller. If the given notifier block was the * last one associated with its specific event, returns the status of the * event-disable EC-command. */ int __ssam_notifier_unregister(struct ssam_controller *ctrl, struct ssam_event_notifier *n, bool disable) { u16 rqid = ssh_tc_to_rqid(n->event.id.target_category); struct ssam_nf_refcount_entry *entry; struct ssam_nf_head *nf_head; struct ssam_nf *nf; int status = 0; if (!ssh_rqid_is_event(rqid)) return -EINVAL; nf = &ctrl->cplt.event.notif; nf_head = &nf->head[ssh_rqid_to_event(rqid)]; mutex_lock(&nf->lock); if (!ssam_nfblk_find(nf_head, &n->base)) { mutex_unlock(&nf->lock); return -ENOENT; } /* * If this is an observer notifier, do not attempt to disable the * event, just remove it. */ if (!(n->flags & SSAM_EVENT_NOTIFIER_OBSERVER)) { entry = ssam_nf_refcount_dec(nf, n->event.reg, n->event.id); if (WARN_ON(!entry)) { /* * If this does not return an entry, there's a logic * error somewhere: The notifier block is registered, * but the event refcount entry is not there. Remove * the notifier block anyways. */ status = -ENOENT; goto remove; } status = ssam_nf_refcount_disable_free(ctrl, entry, n->event.flags, disable); } remove: ssam_nfblk_remove(&n->base); mutex_unlock(&nf->lock); synchronize_srcu(&nf_head->srcu); return status; } EXPORT_SYMBOL_GPL(__ssam_notifier_unregister); /** * ssam_controller_event_enable() - Enable the specified event. * @ctrl: The controller to enable the event for. * @reg: The event registry to use for enabling the event. * @id: The event ID specifying the event to be enabled. * @flags: The SAM event flags used for enabling the event. * * Increment the event reference count of the specified event. If the event has * not been enabled previously, it will be enabled by this call. * * Note: In general, ssam_notifier_register() with a non-observer notifier * should be preferred for enabling/disabling events, as this will guarantee * proper ordering and event forwarding in case of errors during event * enabling/disabling. * * Return: Returns zero on success, %-ENOSPC if the reference count for the * specified event has reached its maximum, %-ENOMEM if the corresponding event * entry could not be allocated. If this is the first time that this event has * been enabled (i.e. the reference count was incremented from zero to one by * this call), returns the status of the event-enable EC-command. */ int ssam_controller_event_enable(struct ssam_controller *ctrl, struct ssam_event_registry reg, struct ssam_event_id id, u8 flags) { u16 rqid = ssh_tc_to_rqid(id.target_category); struct ssam_nf *nf = &ctrl->cplt.event.notif; struct ssam_nf_refcount_entry *entry; int status; if (!ssh_rqid_is_event(rqid)) return -EINVAL; mutex_lock(&nf->lock); entry = ssam_nf_refcount_inc(nf, reg, id); if (IS_ERR(entry)) { mutex_unlock(&nf->lock); return PTR_ERR(entry); } status = ssam_nf_refcount_enable(ctrl, entry, flags); if (status) { ssam_nf_refcount_dec_free(nf, reg, id); mutex_unlock(&nf->lock); return status; } mutex_unlock(&nf->lock); return 0; } EXPORT_SYMBOL_GPL(ssam_controller_event_enable); /** * ssam_controller_event_disable() - Disable the specified event. * @ctrl: The controller to disable the event for. * @reg: The event registry to use for disabling the event. * @id: The event ID specifying the event to be disabled. * @flags: The flags used when enabling the event. * * Decrement the reference count of the specified event. If the reference count * reaches zero, the event will be disabled. * * Note: In general, ssam_notifier_register()/ssam_notifier_unregister() with a * non-observer notifier should be preferred for enabling/disabling events, as * this will guarantee proper ordering and event forwarding in case of errors * during event enabling/disabling. * * Return: Returns zero on success, %-ENOENT if the given event has not been * enabled on the controller. If the reference count of the event reaches zero * during this call, returns the status of the event-disable EC-command. */ int ssam_controller_event_disable(struct ssam_controller *ctrl, struct ssam_event_registry reg, struct ssam_event_id id, u8 flags) { u16 rqid = ssh_tc_to_rqid(id.target_category); struct ssam_nf *nf = &ctrl->cplt.event.notif; struct ssam_nf_refcount_entry *entry; int status; if (!ssh_rqid_is_event(rqid)) return -EINVAL; mutex_lock(&nf->lock); entry = ssam_nf_refcount_dec(nf, reg, id); if (!entry) { mutex_unlock(&nf->lock); return -ENOENT; } status = ssam_nf_refcount_disable_free(ctrl, entry, flags, true); mutex_unlock(&nf->lock); return status; } EXPORT_SYMBOL_GPL(ssam_controller_event_disable); /** * ssam_notifier_disable_registered() - Disable events for all registered * notifiers. * @ctrl: The controller for which to disable the notifiers/events. * * Disables events for all currently registered notifiers. In case of an error * (EC command failing), all previously disabled events will be restored and * the error code returned. * * This function is intended to disable all events prior to hibernation entry. * See ssam_notifier_restore_registered() to restore/re-enable all events * disabled with this function. * * Note that this function will not disable events for notifiers registered * after calling this function. It should thus be made sure that no new * notifiers are going to be added after this call and before the corresponding * call to ssam_notifier_restore_registered(). * * Return: Returns zero on success. In case of failure returns the error code * returned by the failed EC command to disable an event. */ int ssam_notifier_disable_registered(struct ssam_controller *ctrl) { struct ssam_nf *nf = &ctrl->cplt.event.notif; struct rb_node *n; int status; mutex_lock(&nf->lock); for (n = rb_first(&nf->refcount); n; n = rb_next(n)) { struct ssam_nf_refcount_entry *e; e = rb_entry(n, struct ssam_nf_refcount_entry, node); status = ssam_ssh_event_disable(ctrl, e->key.reg, e->key.id, e->flags); if (status) goto err; } mutex_unlock(&nf->lock); return 0; err: for (n = rb_prev(n); n; n = rb_prev(n)) { struct ssam_nf_refcount_entry *e; e = rb_entry(n, struct ssam_nf_refcount_entry, node); ssam_ssh_event_enable(ctrl, e->key.reg, e->key.id, e->flags); } mutex_unlock(&nf->lock); return status; } /** * ssam_notifier_restore_registered() - Restore/re-enable events for all * registered notifiers. * @ctrl: The controller for which to restore the notifiers/events. * * Restores/re-enables all events for which notifiers have been registered on * the given controller. In case of a failure, the error is logged and the * function continues to try and enable the remaining events. * * This function is intended to restore/re-enable all registered events after * hibernation. See ssam_notifier_disable_registered() for the counter part * disabling the events and more details. */ void ssam_notifier_restore_registered(struct ssam_controller *ctrl) { struct ssam_nf *nf = &ctrl->cplt.event.notif; struct rb_node *n; mutex_lock(&nf->lock); for (n = rb_first(&nf->refcount); n; n = rb_next(n)) { struct ssam_nf_refcount_entry *e; e = rb_entry(n, struct ssam_nf_refcount_entry, node); /* Ignore errors, will get logged in call. */ ssam_ssh_event_enable(ctrl, e->key.reg, e->key.id, e->flags); } mutex_unlock(&nf->lock); } /** * ssam_notifier_is_empty() - Check if there are any registered notifiers. * @ctrl: The controller to check on. * * Return: Returns %true if there are currently no notifiers registered on the * controller, %false otherwise. */ static bool ssam_notifier_is_empty(struct ssam_controller *ctrl) { struct ssam_nf *nf = &ctrl->cplt.event.notif; bool result; mutex_lock(&nf->lock); result = ssam_nf_refcount_empty(nf); mutex_unlock(&nf->lock); return result; } /** * ssam_notifier_unregister_all() - Unregister all currently registered * notifiers. * @ctrl: The controller to unregister the notifiers on. * * Unregisters all currently registered notifiers. This function is used to * ensure that all notifiers will be unregistered and associated * entries/resources freed when the controller is being shut down. */ static void ssam_notifier_unregister_all(struct ssam_controller *ctrl) { struct ssam_nf *nf = &ctrl->cplt.event.notif; struct ssam_nf_refcount_entry *e, *n; mutex_lock(&nf->lock); rbtree_postorder_for_each_entry_safe(e, n, &nf->refcount, node) { /* Ignore errors, will get logged in call. */ ssam_ssh_event_disable(ctrl, e->key.reg, e->key.id, e->flags); kfree(e); } nf->refcount = RB_ROOT; mutex_unlock(&nf->lock); } /* -- Wakeup IRQ. ----------------------------------------------------------- */ static irqreturn_t ssam_irq_handle(int irq, void *dev_id) { struct ssam_controller *ctrl = dev_id; ssam_dbg(ctrl, "pm: wake irq triggered\n"); /* * Note: Proper wakeup detection is currently unimplemented. * When the EC is in display-off or any other non-D0 state, it * does not send events/notifications to the host. Instead it * signals that there are events available via the wakeup IRQ. * This driver is responsible for calling back to the EC to * release these events one-by-one. * * This IRQ should not cause a full system resume by its own. * Instead, events should be handled by their respective subsystem * drivers, which in turn should signal whether a full system * resume should be performed. * * TODO: Send GPIO callback command repeatedly to EC until callback * returns 0x00. Return flag of callback is "has more events". * Each time the command is sent, one event is "released". Once * all events have been released (return = 0x00), the GPIO is * re-armed. Detect wakeup events during this process, go back to * sleep if no wakeup event has been received. */ return IRQ_HANDLED; } /** * ssam_irq_setup() - Set up SAM EC wakeup-GPIO interrupt. * @ctrl: The controller for which the IRQ should be set up. * * Set up an IRQ for the wakeup-GPIO pin of the SAM EC. This IRQ can be used * to wake the device from a low power state. * * Note that this IRQ can only be triggered while the EC is in the display-off * state. In this state, events are not sent to the host in the usual way. * Instead the wakeup-GPIO gets pulled to "high" as long as there are pending * events and these events need to be released one-by-one via the GPIO * callback request, either until there are no events left and the GPIO is * reset, or all at once by transitioning the EC out of the display-off state, * which will also clear the GPIO. * * Not all events, however, should trigger a full system wakeup. Instead the * driver should, if necessary, inspect and forward each event to the * corresponding subsystem, which in turn should decide if the system needs to * be woken up. This logic has not been implemented yet, thus wakeup by this * IRQ should be disabled by default to avoid spurious wake-ups, caused, for * example, by the remaining battery percentage changing. Refer to comments in * this function and comments in the corresponding IRQ handler for more * details on how this should be implemented. * * See also ssam_ctrl_notif_display_off() and ssam_ctrl_notif_display_off() * for functions to transition the EC into and out of the display-off state as * well as more details on it. * * The IRQ is disabled by default and has to be enabled before it can wake up * the device from suspend via ssam_irq_arm_for_wakeup(). On teardown, the IRQ * should be freed via ssam_irq_free(). */ int ssam_irq_setup(struct ssam_controller *ctrl) { struct device *dev = ssam_controller_device(ctrl); struct gpio_desc *gpiod; int irq; int status; /* * The actual GPIO interrupt is declared in ACPI as TRIGGER_HIGH. * However, the GPIO line only gets reset by sending the GPIO callback * command to SAM (or alternatively the display-on notification). As * proper handling for this interrupt is not implemented yet, leaving * the IRQ at TRIGGER_HIGH would cause an IRQ storm (as the callback * never gets sent and thus the line never gets reset). To avoid this, * mark the IRQ as TRIGGER_RISING for now, only creating a single * interrupt, and let the SAM resume callback during the controller * resume process clear it. */ const int irqf = IRQF_ONESHOT | IRQF_TRIGGER_RISING | IRQF_NO_AUTOEN; gpiod = gpiod_get(dev, "ssam_wakeup-int", GPIOD_ASIS); if (IS_ERR(gpiod)) return PTR_ERR(gpiod); irq = gpiod_to_irq(gpiod); gpiod_put(gpiod); if (irq < 0) return irq; status = request_threaded_irq(irq, NULL, ssam_irq_handle, irqf, "ssam_wakeup", ctrl); if (status) return status; ctrl->irq.num = irq; return 0; } /** * ssam_irq_free() - Free SAM EC wakeup-GPIO interrupt. * @ctrl: The controller for which the IRQ should be freed. * * Free the wakeup-GPIO IRQ previously set-up via ssam_irq_setup(). */ void ssam_irq_free(struct ssam_controller *ctrl) { free_irq(ctrl->irq.num, ctrl); ctrl->irq.num = -1; } /** * ssam_irq_arm_for_wakeup() - Arm the EC IRQ for wakeup, if enabled. * @ctrl: The controller for which the IRQ should be armed. * * Sets up the IRQ so that it can be used to wake the device. Specifically, * this function enables the irq and then, if the device is allowed to wake up * the system, calls enable_irq_wake(). See ssam_irq_disarm_wakeup() for the * corresponding function to disable the IRQ. * * This function is intended to arm the IRQ before entering S2idle suspend. * * Note: calls to ssam_irq_arm_for_wakeup() and ssam_irq_disarm_wakeup() must * be balanced. */ int ssam_irq_arm_for_wakeup(struct ssam_controller *ctrl) { struct device *dev = ssam_controller_device(ctrl); int status; enable_irq(ctrl->irq.num); if (device_may_wakeup(dev)) { status = enable_irq_wake(ctrl->irq.num); if (status) { ssam_err(ctrl, "failed to enable wake IRQ: %d\n", status); disable_irq(ctrl->irq.num); return status; } ctrl->irq.wakeup_enabled = true; } else { ctrl->irq.wakeup_enabled = false; } return 0; } /** * ssam_irq_disarm_wakeup() - Disarm the wakeup IRQ. * @ctrl: The controller for which the IRQ should be disarmed. * * Disarm the IRQ previously set up for wake via ssam_irq_arm_for_wakeup(). * * This function is intended to disarm the IRQ after exiting S2idle suspend. * * Note: calls to ssam_irq_arm_for_wakeup() and ssam_irq_disarm_wakeup() must * be balanced. */ void ssam_irq_disarm_wakeup(struct ssam_controller *ctrl) { int status; if (ctrl->irq.wakeup_enabled) { status = disable_irq_wake(ctrl->irq.num); if (status) ssam_err(ctrl, "failed to disable wake IRQ: %d\n", status); ctrl->irq.wakeup_enabled = false; } disable_irq(ctrl->irq.num); }
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