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Diffstat (limited to 'drivers/platform/surface/aggregator/controller.c')
| -rw-r--r-- | drivers/platform/surface/aggregator/controller.c | 2807 |
1 files changed, 2807 insertions, 0 deletions
diff --git a/drivers/platform/surface/aggregator/controller.c b/drivers/platform/surface/aggregator/controller.c new file mode 100644 index 000000000..30cea324f --- /dev/null +++ b/drivers/platform/surface/aggregator/controller.c @@ -0,0 +1,2807 @@ +// 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->tid_in; + 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_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_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_sync); + +/** + * ssam_request_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_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_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_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 = 0x01, + .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 = 0x01, + .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 = 0x01, + .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 = 0x01, + .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 = 0x01, + .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_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); +} |