From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
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@xxxxxxxxx>
---
drivers/media/cec/cec-adap.c | 128 +++++++++++++++++++++++++------------------
drivers/media/cec/cec-api.c | 48 +++++++++++-----
include/media/cec.h | 14 ++++-
include/uapi/linux/cec.h | 3 +-
4 files changed, 124 insertions(+), 69 deletions(-)
diff --git a/drivers/media/cec/cec-adap.c b/drivers/media/cec/cec-adap.c
index b3163716d95f..67ec66c7c4ff 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;
+
+ 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;
+ }
- /*
- * 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 (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;
-
- entry->msg = *msg;
- /* Add new msg at the end of the queue */
- list_add_tail(&entry->list, &fh->msgs);
+ if (entry) {
+ 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 queue now has more than CEC_MAX_MSG_RX_QUEUE_SZ
- * messages, drop the oldest one and send a lost message event.
- */
- if (fh->queued_msgs == CEC_MAX_MSG_RX_QUEUE_SZ) {
+ /*
+ * 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);
- goto lost_msgs;
+ kfree(entry);
}
- 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);
+ /*
+ * We lost a message, either because kmalloc failed or the queue
+ * was full.
+ */
+ cec_queue_event_fh(fh, &ev_lost_msgs, ktime_get_ns());
}
/*
diff --git a/drivers/media/cec/cec-api.c b/drivers/media/cec/cec-api.c
index f7eb4c54a354..48bef1c718ad 100644
--- a/drivers/media/cec/cec-api.c
+++ b/drivers/media/cec/cec-api.c
@@ -57,7 +57,7 @@ static unsigned int cec_poll(struct file *filp,
res |= POLLOUT | POLLWRNORM;
if (fh->queued_msgs)
res |= POLLIN | POLLRDNORM;
- if (fh->pending_events)
+ if (fh->total_queued_events)
res |= POLLPRI;
poll_wait(filp, &fh->wait, poll);
mutex_unlock(&adap->lock);
@@ -289,15 +289,17 @@ static long cec_receive(struct cec_adapter *adap, struct cec_fh *fh,
static long cec_dqevent(struct cec_adapter *adap, struct cec_fh *fh,
bool block, struct cec_event __user *parg)
{
- struct cec_event *ev = NULL;
+ struct cec_event_entry *ev = NULL;
u64 ts = ~0ULL;
unsigned int i;
+ unsigned int ev_idx;
long err = 0;
mutex_lock(&fh->lock);
- while (!fh->pending_events && block) {
+ while (!fh->total_queued_events && block) {
mutex_unlock(&fh->lock);
- err = wait_event_interruptible(fh->wait, fh->pending_events);
+ err = wait_event_interruptible(fh->wait,
+ fh->total_queued_events);
if (err)
return err;
mutex_lock(&fh->lock);
@@ -305,23 +307,29 @@ static long cec_dqevent(struct cec_adapter *adap, struct cec_fh *fh,
/* Find the oldest event */
for (i = 0; i < CEC_NUM_EVENTS; i++) {
- if (fh->pending_events & (1 << (i + 1)) &&
- fh->events[i].ts <= ts) {
- ev = &fh->events[i];
- ts = ev->ts;
+ struct cec_event_entry *entry =
+ list_first_entry_or_null(&fh->events[i],
+ struct cec_event_entry, list);
+
+ if (entry && entry->ev.ts <= ts) {
+ ev = entry;
+ ev_idx = i;
+ ts = ev->ev.ts;
}
}
+
if (!ev) {
err = -EAGAIN;
goto unlock;
}
+ list_del(&ev->list);
- if (copy_to_user(parg, ev, sizeof(*ev))) {
+ if (copy_to_user(parg, &ev->ev, sizeof(ev->ev)))
err = -EFAULT;
- goto unlock;
- }
-
- fh->pending_events &= ~(1 << ev->event);
+ if (ev_idx >= CEC_NUM_CORE_EVENTS)
+ kfree(ev);
+ fh->queued_events[ev_idx]--;
+ fh->total_queued_events--;
unlock:
mutex_unlock(&fh->lock);
@@ -495,6 +503,7 @@ static int cec_open(struct inode *inode, struct file *filp)
.event = CEC_EVENT_STATE_CHANGE,
.flags = CEC_EVENT_FL_INITIAL_STATE,
};
+ unsigned int i;
int err;
if (!fh)
@@ -502,6 +511,8 @@ static int cec_open(struct inode *inode, struct file *filp)
INIT_LIST_HEAD(&fh->msgs);
INIT_LIST_HEAD(&fh->xfer_list);
+ for (i = 0; i < CEC_NUM_EVENTS; i++)
+ INIT_LIST_HEAD(&fh->events[i]);
mutex_init(&fh->lock);
init_waitqueue_head(&fh->wait);
@@ -544,6 +555,7 @@ static int cec_release(struct inode *inode, struct file *filp)
struct cec_devnode *devnode = cec_devnode_data(filp);
struct cec_adapter *adap = to_cec_adapter(devnode);
struct cec_fh *fh = filp->private_data;
+ unsigned int i;
mutex_lock(&adap->lock);
if (adap->cec_initiator == fh)
@@ -585,6 +597,16 @@ static int cec_release(struct inode *inode, struct file *filp)
list_del(&entry->list);
kfree(entry);
}
+ for (i = CEC_NUM_CORE_EVENTS; i < CEC_NUM_EVENTS; i++) {
+ while (!list_empty(&fh->events[i])) {
+ struct cec_event_entry *entry =
+ list_first_entry(&fh->events[i],
+ struct cec_event_entry, list);
+
+ list_del(&entry->list);
+ kfree(entry);
+ }
+ }
kfree(fh);
cec_put_device(devnode);
diff --git a/include/media/cec.h b/include/media/cec.h
index 37768203572d..6cc862af74e5 100644
--- a/include/media/cec.h
+++ b/include/media/cec.h
@@ -81,7 +81,13 @@ struct cec_msg_entry {
struct cec_msg msg;
};
-#define CEC_NUM_EVENTS CEC_EVENT_LOST_MSGS
+struct cec_event_entry {
+ struct list_head list;
+ struct cec_event ev;
+};
+
+#define CEC_NUM_CORE_EVENTS 2
+#define CEC_NUM_EVENTS CEC_EVENT_PIN_HIGH
struct cec_fh {
struct list_head list;
@@ -92,9 +98,11 @@ struct cec_fh {
/* Events */
wait_queue_head_t wait;
- unsigned int pending_events;
- struct cec_event events[CEC_NUM_EVENTS];
struct mutex lock;
+ struct list_head events[CEC_NUM_EVENTS]; /* queued events */
+ u8 queued_events[CEC_NUM_EVENTS];
+ unsigned int total_queued_events;
+ struct cec_event_entry core_events[CEC_NUM_CORE_EVENTS];
struct list_head msgs; /* queued messages */
unsigned int queued_msgs;
};
diff --git a/include/uapi/linux/cec.h b/include/uapi/linux/cec.h
index bba73f33c8aa..d87a67b0bb06 100644
--- a/include/uapi/linux/cec.h
+++ b/include/uapi/linux/cec.h
@@ -412,6 +412,7 @@ struct cec_log_addrs {
#define CEC_EVENT_PIN_HIGH 4
#define CEC_EVENT_FL_INITIAL_STATE (1 << 0)
+#define CEC_EVENT_FL_DROPPED_EVENTS (1 << 1)
/**
* struct cec_event_state_change - used when the CEC adapter changes state.
@@ -424,7 +425,7 @@ struct cec_event_state_change {
};
/**
- * struct cec_event_lost_msgs - tells you how many messages were lost due.
+ * struct cec_event_lost_msgs - tells you how many messages were lost.
* @lost_msgs: how many messages were lost.
*/
struct cec_event_lost_msgs {
--
2.11.0
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