V4L/DVB (9726): cx18: Restore buffers that have fallen out of the transfer rotation

Restore buffers that have fallen out of the transfer rotation, and check
for coherent mailbox data when processing a stale mailbox.

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

1 files changed, 45 insertions, 14 deletions

diff --git a/drivers/media/video/cx18/cx18-queue.c b/drivers/media/video/cx18/cx18-queue.c
index 5a3839403631..ff6df36328fd 100644
--- a/drivers/media/video/cx18/cx18-queue.c
+++ b/drivers/media/video/cx18/cx18-queue.c
@@ -49,6 +49,7 @@ void cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
                 buf->bytesused = 0;
                 buf->readpos = 0;
                 buf->b_flags = 0;
+                buf->skipped = 0;
         }
         mutex_lock(&s->qlock);
         list_add_tail(&buf->list, &q->list);
@@ -67,6 +68,7 @@ struct cx18_buffer *cx18_dequeue(struct cx18_stream *s, struct cx18_queue *q)
                 list_del_init(q->list.next);
                 atomic_dec(&q->buffers);
                 q->bytesused -= buf->bytesused - buf->readpos;
+                buf->skipped = 0;
         }
         mutex_unlock(&s->qlock);
         return buf;
@@ -76,34 +78,63 @@ struct cx18_buffer *cx18_queue_get_buf(struct cx18_stream *s, u32 id,
         u32 bytesused)
 {
         struct cx18 *cx = s->cx;
-        struct list_head *p;
+        struct cx18_buffer *buf;
+        struct cx18_buffer *ret = NULL;
+        struct list_head *p, *t;
+        LIST_HEAD(r);
 
         mutex_lock(&s->qlock);
-        list_for_each(p, &s->q_free.list) {
-                struct cx18_buffer *buf =
-                        list_entry(p, struct cx18_buffer, list);
+        list_for_each_safe(p, t, &s->q_free.list) {
+                buf = list_entry(p, struct cx18_buffer, list);
 
                 if (buf->id != id) {
-                        CX18_DEBUG_HI_DMA("Skipping buffer %d searching for %d "
-                                          "in stream %s q_free\n", buf->id, id,
-                                          s->name);
+                        buf->skipped++;
+                        if (buf->skipped >= atomic_read(&s->q_free.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);
+                        }
                         continue;
                 }
 
                 buf->bytesused = bytesused;
-                if (s->type != CX18_ENC_STREAM_TYPE_TS) {
-                        atomic_dec(&s->q_free.buffers);
+                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
+                         * buffers, we want the TS to requeue the buffer just
+                         * before sending the MDL back to the firmware, so we
+                         * pull it off the list here.
+                         */
+                        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);
                 }
 
-                mutex_unlock(&s->qlock);
-                return buf;
+                ret = buf;
+                break;
         }
         mutex_unlock(&s->qlock);
-        CX18_ERR("Cannot find buffer %d for stream %s\n", id, s->name);
-        return NULL;
+
+        /* 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... */
+        }
+        return ret;
 }
 
 /* Move all buffers of a queue to q_free, while flushing the buffers */
@@ -118,7 +149,7 @@ static void cx18_queue_flush(struct cx18_stream *s, struct cx18_queue *q)
         while (!list_empty(&q->list)) {
                 buf = list_entry(q->list.next, struct cx18_buffer, list);
                 list_move_tail(q->list.next, &s->q_free.list);
-                buf->bytesused = buf->readpos = buf->b_flags = 0;
+                buf->bytesused = buf->readpos = buf->b_flags = buf->skipped = 0;
                 atomic_inc(&s->q_free.buffers);
         }
         cx18_queue_init(q);