media: venus: make decoder compliant with stateful codec API

This refactors code for start/stop streaming vb2 operations and
adds a state machine handling similar to the one in stateful codec
API documentation. One major change is that now the HFI session is
started on STREAMON(OUTPUT) and stopped on REQBUF(OUTPUT,count=0),
during that time STREAMOFF(CAP,OUT) just flush buffers but doesn't
stop the session. The other major change is that now the capture
and output queues are completely separated.
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/platform/qcom/venus/core.h

@@ -209,6 +209,17 @@ struct venus_buffer {
 
 #define to_venus_buffer(ptr)	container_of(ptr, struct venus_buffer, vb)
 
+enum venus_dec_state {
+	VENUS_DEC_STATE_DEINIT		= 0,
+	VENUS_DEC_STATE_INIT		= 1,
+	VENUS_DEC_STATE_CAPTURE_SETUP	= 2,
+	VENUS_DEC_STATE_STOPPED		= 3,
+	VENUS_DEC_STATE_SEEK		= 4,
+	VENUS_DEC_STATE_DRAIN		= 5,
+	VENUS_DEC_STATE_DECODING	= 6,
+	VENUS_DEC_STATE_DRC		= 7
+};
+
 /**
  * struct venus_inst - holds per instance parameters
  *
@@ -232,6 +243,10 @@ struct venus_buffer {
  * @colorspace:	current color space
  * @quantization:	current quantization
  * @xfer_func:	current xfer function
+ * @codec_state:	current codec API state (see DEC/ENC_STATE_)
+ * @reconf_wait:	wait queue for resolution change event
+ * @subscriptions:	used to hold current events subscriptions
+ * @buf_count:		used to count number of buffers (reqbuf(0))
  * @fps:		holds current FPS
  * @timeperframe:	holds current time per frame structure
  * @fmt_out:	a reference to output format structure
@@ -246,8 +261,6 @@ struct venus_buffer {
  * @opb_buftype:	output picture buffer type
  * @opb_fmt:		output picture buffer raw format
  * @reconfig:	a flag raised by decoder when the stream resolution changed
- * @reconfig_width:	holds the new width
- * @reconfig_height:	holds the new height
  * @hfi_codec:		current codec for this instance in HFI space
  * @sequence_cap:	a sequence counter for capture queue
  * @sequence_out:	a sequence counter for output queue
@@ -287,6 +300,10 @@ struct venus_inst {
 	u8 ycbcr_enc;
 	u8 quantization;
 	u8 xfer_func;
+	enum venus_dec_state codec_state;
+	wait_queue_head_t reconf_wait;
+	unsigned int subscriptions;
+	int buf_count;
 	u64 fps;
 	struct v4l2_fract timeperframe;
 	const struct venus_format *fmt_out;
@@ -301,8 +318,6 @@ struct venus_inst {
 	u32 opb_buftype;
 	u32 opb_fmt;
 	bool reconfig;
-	u32 reconfig_width;
-	u32 reconfig_height;
 	u32 hfi_codec;
 	u32 sequence_cap;
 	u32 sequence_out;

drivers/media/platform/qcom/venus/helpers.c

@@ -1021,9 +1021,11 @@ void venus_helper_vb2_buf_queue(struct vb2_buffer *vb)
 
 	v4l2_m2m_buf_queue(m2m_ctx, vbuf);
 
-	if (!(inst->streamon_out & inst->streamon_cap))
+	if (inst->session_type == VIDC_SESSION_TYPE_ENC &&
+	    !(inst->streamon_out && inst->streamon_cap))
 		goto unlock;
 
+	if (vb2_start_streaming_called(vb->vb2_queue)) {
 		ret = is_buf_refed(inst, vbuf);
 		if (ret)
 			goto unlock;
@@ -1031,6 +1033,7 @@ void venus_helper_vb2_buf_queue(struct vb2_buffer *vb)
 		ret = session_process_buf(inst, vbuf);
 		if (ret)
 			return_buf_error(inst, vbuf);
+	}
 
 unlock:
 	mutex_unlock(&inst->lock);
@@ -1146,14 +1149,8 @@ int venus_helper_vb2_start_streaming(struct venus_inst *inst)
 	if (ret)
 		goto err_unload_res;
 
-	ret = venus_helper_queue_dpb_bufs(inst);
-	if (ret)
-		goto err_session_stop;
-
 	return 0;
 
-err_session_stop:
-	hfi_session_stop(inst);
 err_unload_res:
 	hfi_session_unload_res(inst);
 err_unreg_bufs: