FROMLIST: media: iris: Add codec specific check for VP9 decoder drain handling

Add a codec specific for the VP9 decoder to ensure that a non-null
buffer is sent to the firmware during drain. The firmware enforces a
check for VP9 decoder that the number of buffers queued and dequeued on
the output plane should match. When a null buffer is sent, the firmware
does not return a response for it, leading to a count mismatch and an
assertion failure from the firmware.

Link: https://lore.kernel.org/linux-arm-msm/20250509-video-iris-hevc-vp9-v5-26-59b4ff7d331c@quicinc.com/
Acked-by: Vikash Garodia <quic_vgarodia@quicinc.com>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-HDK
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8650-QRD
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8650-HDK
Tested-by: Vikash Garodia <quic_vgarodia@quicinc.com> # on sa8775p-ride
Signed-off-by: Dikshita Agarwal <quic_dikshita@quicinc.com>

Author: Dikshita Agarwal

drivers/media/platform/qcom/iris/iris_hfi_gen1_command.c

@@ -401,6 +401,8 @@ static int iris_hfi_gen1_session_drain(struct iris_inst *inst, u32 plane)
 	ip_pkt.shdr.hdr.pkt_type = HFI_CMD_SESSION_EMPTY_BUFFER;
 	ip_pkt.shdr.session_id = inst->session_id;
 	ip_pkt.flags = HFI_BUFFERFLAG_EOS;
+	if (inst->codec == V4L2_PIX_FMT_VP9)
+		ip_pkt.packet_buffer = 0xdeadb000;
 
 	return iris_hfi_queue_cmd_write(inst->core, &ip_pkt, ip_pkt.shdr.hdr.size);
 }

drivers/media/platform/qcom/iris/iris_hfi_gen1_response.c

@@ -348,6 +348,10 @@ static void iris_hfi_gen1_session_etb_done(struct iris_inst *inst, void *packet)
 	struct iris_buffer *buf = NULL;
 	bool found = false;
 
+	/* EOS buffer sent via drain won't be in v4l2 buffer list */
+	if (pkt->packet_buffer == 0xdeadb000)
+		return;
+
 	v4l2_m2m_for_each_src_buf_safe(m2m_ctx, m2m_buffer, n) {
 		buf = to_iris_buffer(&m2m_buffer->vb);
 		if (buf->index == pkt->input_tag) {