media: cec: rework the cec event handling
Event handling was always fairly simplistic since there were only
two events. With the addition of pin events this needed to be redesigned.
The state_change and lost_msgs events are now core events with the
guarantee that the last state is always available. The new pin events
are a queue of events (up to 64 for each event) and the oldest event
will be dropped if the application cannot keep up. Lost events are
marked with a new event flag.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/drivers/media/cec/cec-adap.c b/drivers/media/cec/cec-adap.c
index 82c1633..5080d7aa 100644
--- a/drivers/media/cec/cec-adap.c
+++ b/drivers/media/cec/cec-adap.c
@@ -78,42 +78,62 @@ static unsigned int cec_log_addr2dev(const struct cec_adapter *adap, u8 log_addr
* Queue a new event for this filehandle. If ts == 0, then set it
* to the current time.
*
- * The two events that are currently defined do not need to keep track
- * of intermediate events, so no actual queue of events is needed,
- * instead just store the latest state and the total number of lost
- * messages.
- *
- * Should new events be added in the future that require intermediate
- * results to be queued as well, then a proper queue data structure is
- * required. But until then, just keep it simple.
+ * We keep a queue of at most max_event events where max_event differs
+ * per event. If the queue becomes full, then drop the oldest event and
+ * keep track of how many events we've dropped.
*/
void cec_queue_event_fh(struct cec_fh *fh,
const struct cec_event *new_ev, u64 ts)
{
- struct cec_event *ev = &fh->events[new_ev->event - 1];
+ static const u8 max_events[CEC_NUM_EVENTS] = {
+ 1, 1, 64, 64,
+ };
+ struct cec_event_entry *entry;
+ unsigned int ev_idx = new_ev->event - 1;
+
+ if (WARN_ON(ev_idx >= ARRAY_SIZE(fh->events)))
+ return;
if (ts == 0)
ts = ktime_get_ns();
mutex_lock(&fh->lock);
- if (new_ev->event == CEC_EVENT_LOST_MSGS &&
- fh->pending_events & (1 << new_ev->event)) {
- /*
- * If there is already a lost_msgs event, then just
- * update the lost_msgs count. This effectively
- * merges the old and new events into one.
- */
- ev->lost_msgs.lost_msgs += new_ev->lost_msgs.lost_msgs;
- goto unlock;
- }
+ if (ev_idx < CEC_NUM_CORE_EVENTS)
+ entry = &fh->core_events[ev_idx];
+ else
+ entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+ if (entry) {
+ if (new_ev->event == CEC_EVENT_LOST_MSGS &&
+ fh->queued_events[ev_idx]) {
+ entry->ev.lost_msgs.lost_msgs +=
+ new_ev->lost_msgs.lost_msgs;
+ goto unlock;
+ }
+ entry->ev = *new_ev;
+ entry->ev.ts = ts;
- /*
- * Intermediate states are not interesting, so just
- * overwrite any older event.
- */
- *ev = *new_ev;
- ev->ts = ts;
- fh->pending_events |= 1 << new_ev->event;
+ if (fh->queued_events[ev_idx] < max_events[ev_idx]) {
+ /* Add new msg at the end of the queue */
+ list_add_tail(&entry->list, &fh->events[ev_idx]);
+ fh->queued_events[ev_idx]++;
+ fh->total_queued_events++;
+ goto unlock;
+ }
+
+ if (ev_idx >= CEC_NUM_CORE_EVENTS) {
+ list_add_tail(&entry->list, &fh->events[ev_idx]);
+ /* drop the oldest event */
+ entry = list_first_entry(&fh->events[ev_idx],
+ struct cec_event_entry, list);
+ list_del(&entry->list);
+ kfree(entry);
+ }
+ }
+ /* Mark that events were lost */
+ entry = list_first_entry_or_null(&fh->events[ev_idx],
+ struct cec_event_entry, list);
+ if (entry)
+ entry->ev.flags |= CEC_EVENT_FL_DROPPED_EVENTS;
unlock:
mutex_unlock(&fh->lock);
@@ -134,46 +154,50 @@ static void cec_queue_event(struct cec_adapter *adap,
}
/*
- * Queue a new message for this filehandle. If there is no more room
- * in the queue, then send the LOST_MSGS event instead.
+ * Queue a new message for this filehandle.
+ *
+ * We keep a queue of at most CEC_MAX_MSG_RX_QUEUE_SZ messages. If the
+ * queue becomes full, then drop the oldest message and keep track
+ * of how many messages we've dropped.
*/
static void cec_queue_msg_fh(struct cec_fh *fh, const struct cec_msg *msg)
{
- static const struct cec_event ev_lost_msg = {
- .ts = 0,
+ static const struct cec_event ev_lost_msgs = {
.event = CEC_EVENT_LOST_MSGS,
- .flags = 0,
- {
- .lost_msgs.lost_msgs = 1,
- },
+ .lost_msgs.lost_msgs = 1,
};
struct cec_msg_entry *entry;
mutex_lock(&fh->lock);
entry = kmalloc(sizeof(*entry), GFP_KERNEL);
- if (!entry)
- goto lost_msgs;
+ if (entry) {
+ entry->msg = *msg;
+ /* Add new msg at the end of the queue */
+ list_add_tail(&entry->list, &fh->msgs);
- entry->msg = *msg;
- /* Add new msg at the end of the queue */
- list_add_tail(&entry->list, &fh->msgs);
+ if (fh->queued_msgs < CEC_MAX_MSG_RX_QUEUE_SZ) {
+ /* All is fine if there is enough room */
+ fh->queued_msgs++;
+ mutex_unlock(&fh->lock);
+ wake_up_interruptible(&fh->wait);
+ return;
+ }
+
+ /*
+ * if the message queue is full, then drop the oldest one and
+ * send a lost message event.
+ */
+ entry = list_first_entry(&fh->msgs, struct cec_msg_entry, list);
+ list_del(&entry->list);
+ kfree(entry);
+ }
+ mutex_unlock(&fh->lock);
/*
- * if the queue now has more than CEC_MAX_MSG_RX_QUEUE_SZ
- * messages, drop the oldest one and send a lost message event.
+ * We lost a message, either because kmalloc failed or the queue
+ * was full.
*/
- if (fh->queued_msgs == CEC_MAX_MSG_RX_QUEUE_SZ) {
- list_del(&entry->list);
- goto lost_msgs;
- }
- fh->queued_msgs++;
- mutex_unlock(&fh->lock);
- wake_up_interruptible(&fh->wait);
- return;
-
-lost_msgs:
- mutex_unlock(&fh->lock);
- cec_queue_event_fh(fh, &ev_lost_msg, 0);
+ cec_queue_event_fh(fh, &ev_lost_msgs, ktime_get_ns());
}
/*