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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>
This commit is contained in:
Hans Verkuil 2017-07-11 03:30:39 -03:00 committed by Mauro Carvalho Chehab
parent 6303d97873
commit 6b2bbb0874
4 changed files with 125 additions and 70 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

130
drivers/media/cec/cec-adap.c
View File

@ -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());
}
/*

48
drivers/media/cec/cec-api.c
View File

@ -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);

14
include/media/cec.h
View File

@ -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;
};

3
include/uapi/linux/cec.h
View File

@ -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 {