media: coda: flush bitstream ring buffer on decoder restart

The bitstream ringbuffer might be in an underrun state after draining,
or it might still contain unread data if the previous decoder stop
command was flagged as immediate. Flush the bitstream ring buffer
during V4L2_DEC_CMD_START to get into a well defined state. Also fill
the bitstream with buffers that have been queued during draining,
to resume decoding immediately.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

1 files changed, 20 insertions, 0 deletions

diff --git a/drivers/media/platform/coda/coda-bit.c b/drivers/media/platform/coda/coda-bit.c
index 5a1016243032..843f92312f47 100644
--- a/drivers/media/platform/coda/coda-bit.c
+++ b/drivers/media/platform/coda/coda-bit.c
@@ -199,6 +199,26 @@ static int coda_h264_bitstream_pad(struct coda_ctx *ctx, u32 size)
 	return (n < size) ? -ENOSPC : 0;
 }
 
+int coda_bitstream_flush(struct coda_ctx *ctx)
+{
+	int ret;
+
+	if (ctx->inst_type != CODA_INST_DECODER || !ctx->use_bit)
+		return 0;
+
+	ret = coda_command_sync(ctx, CODA_COMMAND_DEC_BUF_FLUSH);
+	if (ret < 0) {
+		v4l2_err(&ctx->dev->v4l2_dev, "failed to flush bitstream\n");
+		return ret;
+	}
+
+	kfifo_init(&ctx->bitstream_fifo, ctx->bitstream.vaddr,
+		   ctx->bitstream.size);
+	coda_kfifo_sync_to_device_full(ctx);
+
+	return 0;
+}
+
 static int coda_bitstream_queue(struct coda_ctx *ctx, const u8 *buf, u32 size)
 {
 	u32 n = kfifo_in(&ctx->bitstream_fifo, buf, size);