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path: root/drivers/media/video/cx18/cx18-queue.c
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Diffstat (limited to 'drivers/media/video/cx18/cx18-queue.c')
-rw-r--r--drivers/media/video/cx18/cx18-queue.c85
1 files changed, 51 insertions, 34 deletions
diff --git a/drivers/media/video/cx18/cx18-queue.c b/drivers/media/video/cx18/cx18-queue.c
index 3046b8e7434..fa1ed7897d9 100644
--- a/drivers/media/video/cx18/cx18-queue.c
+++ b/drivers/media/video/cx18/cx18-queue.c
@@ -23,8 +23,8 @@
*/
#include "cx18-driver.h"
-#include "cx18-streams.h"
#include "cx18-queue.h"
+#include "cx18-streams.h"
#include "cx18-scb.h"
void cx18_buf_swap(struct cx18_buffer *buf)
@@ -53,13 +53,13 @@ struct cx18_queue *_cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
buf->skipped = 0;
}
- mutex_lock(&s->qlock);
-
/* q_busy is restricted to a max buffer count imposed by firmware */
if (q == &s->q_busy &&
atomic_read(&q->buffers) >= CX18_MAX_FW_MDLS_PER_STREAM)
q = &s->q_free;
+ spin_lock(&q->lock);
+
if (to_front)
list_add(&buf->list, &q->list); /* LIFO */
else
@@ -67,7 +67,7 @@ struct cx18_queue *_cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
q->bytesused += buf->bytesused - buf->readpos;
atomic_inc(&q->buffers);
- mutex_unlock(&s->qlock);
+ spin_unlock(&q->lock);
return q;
}
@@ -75,7 +75,7 @@ struct cx18_buffer *cx18_dequeue(struct cx18_stream *s, struct cx18_queue *q)
{
struct cx18_buffer *buf = NULL;
- mutex_lock(&s->qlock);
+ spin_lock(&q->lock);
if (!list_empty(&q->list)) {
buf = list_first_entry(&q->list, struct cx18_buffer, list);
list_del_init(&buf->list);
@@ -83,7 +83,7 @@ struct cx18_buffer *cx18_dequeue(struct cx18_stream *s, struct cx18_queue *q)
buf->skipped = 0;
atomic_dec(&q->buffers);
}
- mutex_unlock(&s->qlock);
+ spin_unlock(&q->lock);
return buf;
}
@@ -94,9 +94,23 @@ struct cx18_buffer *cx18_queue_get_buf(struct cx18_stream *s, u32 id,
struct cx18_buffer *buf;
struct cx18_buffer *tmp;
struct cx18_buffer *ret = NULL;
-
- mutex_lock(&s->qlock);
+ LIST_HEAD(sweep_up);
+
+ /*
+ * We don't have to acquire multiple q locks here, because we are
+ * serialized by the single threaded work handler.
+ * Buffers from the firmware will thus remain in order as
+ * they are moved from q_busy to q_full or to the dvb ring buffer.
+ */
+ spin_lock(&s->q_busy.lock);
list_for_each_entry_safe(buf, tmp, &s->q_busy.list, list) {
+ /*
+ * We should find what the firmware told us is done,
+ * right at the front of the queue. If we don't, we likely have
+ * missed a buffer done message from the firmware.
+ * Once we skip a buffer repeatedly, relative to the size of
+ * q_busy, we have high confidence we've missed it.
+ */
if (buf->id != id) {
buf->skipped++;
if (buf->skipped >= atomic_read(&s->q_busy.buffers)-1) {
@@ -105,38 +119,41 @@ struct cx18_buffer *cx18_queue_get_buf(struct cx18_stream *s, u32 id,
"times - it must have dropped out of "
"rotation\n", s->name, buf->id,
buf->skipped);
- /* move it to q_free */
- list_move_tail(&buf->list, &s->q_free.list);
- buf->bytesused = buf->readpos = buf->b_flags =
- buf->skipped = 0;
+ /* Sweep it up to put it back into rotation */
+ list_move_tail(&buf->list, &sweep_up);
atomic_dec(&s->q_busy.buffers);
- atomic_inc(&s->q_free.buffers);
}
continue;
}
-
- buf->bytesused = bytesused;
- /* Sync the buffer before we release the qlock */
- cx18_buf_sync_for_cpu(s, buf);
- if (s->type == CX18_ENC_STREAM_TYPE_TS) {
- /*
- * TS doesn't use q_full. As we pull the buffer off of
- * the queue here, the caller will have to put it back.
- */
- list_del_init(&buf->list);
- } else {
- /* Move buffer from q_busy to q_full */
- list_move_tail(&buf->list, &s->q_full.list);
- set_bit(CX18_F_B_NEED_BUF_SWAP, &buf->b_flags);
- s->q_full.bytesused += buf->bytesused;
- atomic_inc(&s->q_full.buffers);
- }
+ /*
+ * We pull the desired buffer off of the queue here. Something
+ * will have to put it back on a queue later.
+ */
+ list_del_init(&buf->list);
atomic_dec(&s->q_busy.buffers);
-
ret = buf;
break;
}
- mutex_unlock(&s->qlock);
+ spin_unlock(&s->q_busy.lock);
+
+ /*
+ * We found the buffer for which we were looking. Get it ready for
+ * the caller to put on q_full or in the dvb ring buffer.
+ */
+ if (ret != NULL) {
+ ret->bytesused = bytesused;
+ ret->skipped = 0;
+ /* readpos and b_flags were 0'ed when the buf went on q_busy */
+ cx18_buf_sync_for_cpu(s, ret);
+ if (s->type != CX18_ENC_STREAM_TYPE_TS)
+ set_bit(CX18_F_B_NEED_BUF_SWAP, &ret->b_flags);
+ }
+
+ /* Put any buffers the firmware is ignoring back into normal rotation */
+ list_for_each_entry_safe(buf, tmp, &sweep_up, list) {
+ list_del_init(&buf->list);
+ cx18_enqueue(s, buf, &s->q_free);
+ }
return ret;
}
@@ -148,7 +165,7 @@ static void cx18_queue_flush(struct cx18_stream *s, struct cx18_queue *q)
if (q == &s->q_free)
return;
- mutex_lock(&s->qlock);
+ spin_lock(&q->lock);
while (!list_empty(&q->list)) {
buf = list_first_entry(&q->list, struct cx18_buffer, list);
list_move_tail(&buf->list, &s->q_free.list);
@@ -156,7 +173,7 @@ static void cx18_queue_flush(struct cx18_stream *s, struct cx18_queue *q)
atomic_inc(&s->q_free.buffers);
}
cx18_queue_init(q);
- mutex_unlock(&s->qlock);
+ spin_unlock(&q->lock);
}
void cx18_flush_queues(struct cx18_stream *s)