From: Hans Verkuil hans.verkuil@cisco.com
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 --- 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 {