V4L/DVB (9801): cx18: Allow more than 63 capture buffers in rotation per stream

cx18: Allow more than 63 capture buffers in rotation per stream.  Implement
q_busy to hold buffers the firmware has for use.  q_free holds truly unused
buffers in a pool.  New buffers are given to the firmware as soon as the
firmware returns one, if there are any to give to the firmware.

Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 29 insertions, 27 deletions

diff --git a/drivers/media/video/cx18/cx18-queue.c b/drivers/media/video/cx18/cx18-queue.c
index fdfc83ee3d4e..40379d807cef 100644
--- a/drivers/media/video/cx18/cx18-queue.c
+++ b/drivers/media/video/cx18/cx18-queue.c
@@ -42,24 +42,32 @@ void cx18_queue_init(struct cx18_queue *q)
         q->bytesused = 0;
 }
 
-void _cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
-                   struct cx18_queue *q, int to_front)
+struct cx18_queue *_cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
+                                 struct cx18_queue *q, int to_front)
 {
-        /* clear the buffer if it is going to be enqueued to the free queue */
-        if (q == &s->q_free) {
+        /* clear the buffer if it is not to be enqueued to the full queue */
+        if (q != &s->q_full) {
                 buf->bytesused = 0;
                 buf->readpos = 0;
                 buf->b_flags = 0;
                 buf->skipped = 0;
         }
+
         mutex_lock(&s->qlock);
+
+        /* q_busy is restricted to 63 buffers to stay within firmware limits */
+        if (q == &s->q_busy && atomic_read(&q->buffers) >= 63)
+                q = &s->q_free;
+
         if (to_front)
                 list_add(&buf->list, &q->list); /* LIFO */
         else
                 list_add_tail(&buf->list, &q->list); /* FIFO */
-        atomic_inc(&q->buffers);
         q->bytesused += buf->bytesused - buf->readpos;
+        atomic_inc(&q->buffers);
+
         mutex_unlock(&s->qlock);
+        return q;
 }
 
 struct cx18_buffer *cx18_dequeue(struct cx18_stream *s, struct cx18_queue *q)
@@ -70,9 +78,9 @@ struct cx18_buffer *cx18_dequeue(struct cx18_stream *s, struct cx18_queue *q)
         if (!list_empty(&q->list)) {
                 buf = list_entry(q->list.next, struct cx18_buffer, list);
                 list_del_init(q->list.next);
-                atomic_dec(&q->buffers);
                 q->bytesused -= buf->bytesused - buf->readpos;
                 buf->skipped = 0;
+                atomic_dec(&q->buffers);
         }
         mutex_unlock(&s->qlock);
         return buf;
@@ -85,28 +93,30 @@ struct cx18_buffer *cx18_queue_get_buf(struct cx18_stream *s, u32 id,
         struct cx18_buffer *buf;
         struct cx18_buffer *ret = NULL;
         struct list_head *p, *t;
-        LIST_HEAD(r);
 
         mutex_lock(&s->qlock);
-        list_for_each_safe(p, t, &s->q_free.list) {
+        list_for_each_safe(p, t, &s->q_busy.list) {
                 buf = list_entry(p, struct cx18_buffer, list);
 
                 if (buf->id != id) {
                         buf->skipped++;
-                        if (buf->skipped >= atomic_read(&s->q_free.buffers)-1) {
+                        if (buf->skipped >= atomic_read(&s->q_busy.buffers)-1) {
                                 /* buffer must have fallen out of rotation */
-                                atomic_dec(&s->q_free.buffers);
-                                list_move_tail(&buf->list, &r);
                                 CX18_WARN("Skipped %s, buffer %d, %d "
                                           "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;
+                                atomic_dec(&s->q_busy.buffers);
+                                atomic_inc(&s->q_free.buffers);
                         }
                         continue;
                 }
 
                 buf->bytesused = bytesused;
-                atomic_dec(&s->q_free.buffers);
                 if (s->type == CX18_ENC_STREAM_TYPE_TS) {
                         /*
                          * TS doesn't use q_full, but for sweeping up lost
@@ -116,28 +126,19 @@ struct cx18_buffer *cx18_queue_get_buf(struct cx18_stream *s, u32 id,
                          */
                         list_del_init(&buf->list);
                 } else {
-                        atomic_inc(&s->q_full.buffers);
-                        s->q_full.bytesused += buf->bytesused;
                         list_move_tail(&buf->list, &s->q_full.list);
+                        s->q_full.bytesused += buf->bytesused;
+                        atomic_inc(&s->q_full.buffers);
                 }
+                atomic_dec(&s->q_busy.buffers);
 
                 ret = buf;
                 break;
         }
-        mutex_unlock(&s->qlock);
 
-        /* Put lost buffers back into firmware transfer rotation */
-        while (!list_empty(&r)) {
-                buf = list_entry(r.next, struct cx18_buffer, list);
-                list_del_init(r.next);
-                cx18_enqueue(s, buf, &s->q_free);
-                cx18_vapi(cx, CX18_CPU_DE_SET_MDL, 5, s->handle,
-                       (void __iomem *)&cx->scb->cpu_mdl[buf->id] - cx->enc_mem,
-                       1, buf->id, s->buf_size);
-                CX18_INFO("Returning %s, buffer %d back to transfer rotation\n",
-                          s->name, buf->id);
-                /* and there was much rejoicing... */
-        }
+        /* Put more buffers into the transfer rotation from q_free, if we can */
+        cx18_stream_load_fw_queue_nolock(s);
+        mutex_unlock(&s->qlock);
         return ret;
 }
 
@@ -162,6 +163,7 @@ static void cx18_queue_flush(struct cx18_stream *s, struct cx18_queue *q)
 
 void cx18_flush_queues(struct cx18_stream *s)
 {
+        cx18_queue_flush(s, &s->q_busy);
         cx18_queue_flush(s, &s->q_full);
 }