Re: [PATCH v4 1/2] media: amphion: Reduce decoding latency for HEVC decoder

[Frank Li]

On Fri, Mar 28, 2025 at 02:48:16PM +0800, ming.qian@xxxxxxxxxxx wrote:
> From: Ming Qian <ming.qian@xxxxxxxxxxx>
>
> The amphion decoder firmware supports a low latency flush mode for the
> HEVC format since v1.9.0. This feature, which is enabled when the
> display delay is set to 0, can help to reduce the decoding latency by
> appending some padding data to every frame.
>
> Signed-off-by: Ming Qian <ming.qian@xxxxxxxxxxx>
> Reviewed-by: Nicolas Dufresne <nicolas.dufresne@xxxxxxxxxxxxx>
> ---
> v4
> - Add CHECK_VERSION macro
> v3
> - Improve commit message as recommended
> v2
> - Improve commit message
> - Add firmware version check
>
>  drivers/media/platform/amphion/vpu_malone.c | 24 ++++++++++++++++++---
>  1 file changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/platform/amphion/vpu_malone.c b/drivers/media/platform/amphion/vpu_malone.c
> index 5c6b2a841b6f..88f8c16a451e 100644
> --- a/drivers/media/platform/amphion/vpu_malone.c
> +++ b/drivers/media/platform/amphion/vpu_malone.c
> @@ -68,6 +68,12 @@
>
>  #define MALONE_DEC_FMT_RV_MASK			BIT(21)
>
> +#define MALONE_VERSION_MASK			0xFFFFF
> +#define MALONE_VERSION(maj, min, inc)		\
> +		((((maj) << 16) | ((min) << 16) | (inc)) & MALONE_VERSION_MASK)
> +#define CHECK_VERSION(iface, maj, min)		\
> +		(((iface)->fw_version & MALONE_VERSION_MASK) >= MALONE_VERSION(maj, min, 0))
> +

Suggest use FIELD_PREP FILED_GET macro because it can check input value
exceed the range.

#define FIELD_PREP(_mask, _val)						\
	({								\
		__BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: ");	\

		^^^^

		((typeof(_mask))(_val) << __bf_shf(_mask)) & (_mask);	\
	})

Frank

>  enum vpu_malone_stream_input_mode {
>  	INVALID_MODE = 0,
>  	FRAME_LVL,
> @@ -332,6 +338,8 @@ struct vpu_dec_ctrl {
>  	u32 buf_addr[VID_API_NUM_STREAMS];
>  };
>
> +static const struct malone_padding_scode *get_padding_scode(u32 type, u32 fmt);
> +
>  u32 vpu_malone_get_data_size(void)
>  {
>  	return sizeof(struct vpu_dec_ctrl);
> @@ -654,9 +662,15 @@ static int vpu_malone_set_params(struct vpu_shared_addr *shared,
>  		hc->jpg[instance].jpg_mjpeg_interlaced = 0;
>  	}
>
> -	hc->codec_param[instance].disp_imm = params->display_delay_enable ? 1 : 0;
> -	if (malone_format != MALONE_FMT_AVC)
> +	if (params->display_delay_enable &&
> +	    get_padding_scode(SCODE_PADDING_BUFFLUSH, params->codec_format))
> +		hc->codec_param[instance].disp_imm = 1;
> +	else
>  		hc->codec_param[instance].disp_imm = 0;
> +
> +	if (params->codec_format == V4L2_PIX_FMT_HEVC && !CHECK_VERSION(iface, 1, 9))
> +		hc->codec_param[instance].disp_imm = 0;
> +
>  	hc->codec_param[instance].dbglog_enable = 0;
>  	iface->dbglog_desc.level = 0;
>
> @@ -1024,6 +1038,7 @@ static const struct malone_padding_scode padding_scodes[] = {
>  	{SCODE_PADDING_EOS,      V4L2_PIX_FMT_JPEG,        {0x0, 0x0}},
>  	{SCODE_PADDING_BUFFLUSH, V4L2_PIX_FMT_H264,        {0x15010000, 0x0}},
>  	{SCODE_PADDING_BUFFLUSH, V4L2_PIX_FMT_H264_MVC,    {0x15010000, 0x0}},
> +	{SCODE_PADDING_BUFFLUSH, V4L2_PIX_FMT_HEVC,        {0x3e010000, 0x20}},
>  };
>
>  static const struct malone_padding_scode padding_scode_dft = {0x0, 0x0};
> @@ -1058,8 +1073,11 @@ static int vpu_malone_add_padding_scode(struct vpu_buffer *stream_buffer,
>  	int ret;
>
>  	ps = get_padding_scode(scode_type, pixelformat);
> -	if (!ps)
> +	if (!ps) {
> +		if (scode_type == SCODE_PADDING_BUFFLUSH)
> +			return 0;
>  		return -EINVAL;
> +	}
>
>  	wptr = readl(&str_buf->wptr);
>  	if (wptr < stream_buffer->phys || wptr > stream_buffer->phys + stream_buffer->length)
> --
> 2.43.0-rc1
>