media: mtk-vcodec: vdec: support stateless H.264 decoding

Add support for H.264 decoding using the stateless API, as supported by
MT8183. This support takes advantage of the V4L2 H.264 reference list
builders.

[acourbot: refactor, cleanup and split]
[tzungbi: fix missing kerneldoc issue]
[hverkuil: fix trivial kerneldoc typo]
Signed-off-by: Yunfei Dong <yunfei.dong@mediatek.com>
Co-developed-by: Alexandre Courbot <acourbot@chromium.org>
Signed-off-by: Alexandre Courbot <acourbot@chromium.org>
Signed-off-by: Tzung-Bi Shih <tzungbi@google.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/platform/Kconfig

@@ -314,6 +314,7 @@ config VIDEO_MEDIATEK_VCODEC
 	select V4L2_MEM2MEM_DEV
 	select VIDEO_MEDIATEK_VCODEC_VPU if VIDEO_MEDIATEK_VPU
 	select VIDEO_MEDIATEK_VCODEC_SCP if MTK_SCP
+	select V4L2_H264
 	help
 	  Mediatek video codec driver provides HW capability to
 	  encode and decode in a range of video formats on MT8173

drivers/media/platform/mtk-vcodec/Makefile

@@ -7,6 +7,7 @@ obj-$(CONFIG_VIDEO_MEDIATEK_VCODEC) += mtk-vcodec-dec.o \
 mtk-vcodec-dec-y := vdec/vdec_h264_if.o \
 		vdec/vdec_vp8_if.o \
 		vdec/vdec_vp9_if.o \
+		vdec/vdec_h264_req_if.o \
 		mtk_vcodec_dec_drv.o \
 		vdec_drv_if.o \
 		vdec_vpu_if.o \

drivers/media/platform/mtk-vcodec/vdec_drv_if.c

@@ -19,6 +19,9 @@ int vdec_if_init(struct mtk_vcodec_ctx *ctx, unsigned int fourcc)
 	int ret = 0;
 
 	switch (fourcc) {
+	case V4L2_PIX_FMT_H264_SLICE:
+		ctx->dec_if = &vdec_h264_slice_if;
+		break;
 	case V4L2_PIX_FMT_H264:
 		ctx->dec_if = &vdec_h264_if;
 		break;

drivers/media/platform/mtk-vcodec/vdec_drv_if.h

@@ -55,6 +55,7 @@ struct vdec_fb_node {
 };
 
 extern const struct vdec_common_if vdec_h264_if;
+extern const struct vdec_common_if vdec_h264_slice_if;
 extern const struct vdec_common_if vdec_vp8_if;
 extern const struct vdec_common_if vdec_vp9_if;