// SPDX-License-Identifier: GPL-2.0+
/*
* Main SSAM/SSH controller structure and functionality.
*
* Copyright (C) 2019-2022 Maximilian Luz <[email protected]>
*/
#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;
/* 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_caps_load_from_of() - Load controller capabilities from OF/DT.
* @dev: A pointer to the controller device
* @caps: Where to store the capabilities in.
*
* Return: Returns zero on success, a negative error code on failure.
*/
static int ssam_controller_caps_load_from_of(struct device *dev, struct ssam_controller_caps *caps)
{
/*
* Every device starting with Surface Pro X through Laptop 7 uses these
* identical values, which makes them good defaults.
*/
caps->d3_closes_handle = true;
caps->screen_on_sleep_idle_timeout = 5000;
caps->screen_off_sleep_idle_timeout = 30;
caps->ssh_buffer_size = 48;
/* TODO: figure out power profile */
return 0;
}
/**
* ssam_controller_caps_load() - Load controller capabilities
* @dev: A pointer to the controller device
* @caps: Where to store the capabilities in.
*
* Return: Returns zero on success, a negative error code on failure.
*/
static int ssam_controller_caps_load(struct device *dev, struct ssam_controller_caps *caps)
{
acpi_handle handle = ACPI_HANDLE(dev);
/* 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;
if (handle)
return ssam_controller_caps_load_from_acpi(handle, caps);
else
return ssam_controller_caps_load_from_of(dev, caps);
}
/**
* 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)
{
int status;
init_rwsem(&ctrl->lock);
kref_init(&ctrl->kref);
status = ssam_controller_caps_load(&serdev->dev, &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 &&
ctrl->state != SSAM_CONTROLLER_INITIALIZED);
/*
* 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)) {
irq = fwnode_irq_get(dev_fwnode(dev), 0);
} else {
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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