Re: [PATCH v8 14/17] media: hantro: Stop using Hantro dedicated control

Benjamin Gaignard
2022-06-14T16:47:19Z

Le 14/06/2022 à 18:23, Nicolas Dufresne a écrit :
> Le mardi 14 juin 2022 à 17:47 +0200, Hans Verkuil a écrit :
>> On 6/14/22 17:43, Nicolas Dufresne wrote:
>>> Le mardi 14 juin 2022 à 15:58 +0200, Hans Verkuil a écrit :
>>>> On 6/14/22 10:36, Benjamin Gaignard wrote:
>>>>> The number of bits to skip in the slice header can be computed
>>>>> in the driver by using sps, pps and decode_params information.
>>>>> This allow to remove Hantro dedicated control.
>>>> allow -> makes it possible
>>>>
>>>>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
>>>>> ---
>>>>> drivers/staging/media/hantro/hantro_drv.c | 36 -----------
>>>>> .../staging/media/hantro/hantro_g2_hevc_dec.c | 62 ++++++++++++++++++-
>>>>> include/media/hevc-ctrls.h | 13 ----
>>>>> 3 files changed, 61 insertions(+), 50 deletions(-)
>>>>>
>>>>> diff --git a/drivers/staging/media/hantro/hantro_drv.c b/drivers/staging/media/hantro/hantro_drv.c
>>>>> index 536c8c374952..5aac3a090480 100644
>>>>> --- a/drivers/staging/media/hantro/hantro_drv.c
>>>>> +++ b/drivers/staging/media/hantro/hantro_drv.c
>>>>> @@ -304,26 +304,6 @@ static int hantro_jpeg_s_ctrl(struct v4l2_ctrl *ctrl)
>>>>> return 0;
>>>>> }
>>>>>
>>>>> -static int hantro_hevc_s_ctrl(struct v4l2_ctrl *ctrl)
>>>>> -{
>>>>> - struct hantro_ctx *ctx;
>>>>> -
>>>>> - ctx = container_of(ctrl->handler,
>>>>> - struct hantro_ctx, ctrl_handler);
>>>>> -
>>>>> - vpu_debug(1, "s_ctrl: id = %d, val = %d\n", ctrl->id, ctrl->val);
>>>>> -
>>>>> - switch (ctrl->id) {
>>>>> - case V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP:
>>>>> - ctx->hevc_dec.ctrls.hevc_hdr_skip_length = ctrl->val;
>>>>> - break;
>>>>> - default:
>>>>> - return -EINVAL;
>>>>> - }
>>>>> -
>>>>> - return 0;
>>>>> -}
>>>>> -
>>>>> static const struct v4l2_ctrl_ops hantro_ctrl_ops = {
>>>>> .try_ctrl = hantro_try_ctrl,
>>>>> };
>>>>> @@ -332,10 +312,6 @@ static const struct v4l2_ctrl_ops hantro_jpeg_ctrl_ops = {
>>>>> .s_ctrl = hantro_jpeg_s_ctrl,
>>>>> };
>>>>>
>>>>> -static const struct v4l2_ctrl_ops hantro_hevc_ctrl_ops = {
>>>>> - .s_ctrl = hantro_hevc_s_ctrl,
>>>>> -};
>>>>> -
>>>>> #define HANTRO_JPEG_ACTIVE_MARKERS (V4L2_JPEG_ACTIVE_MARKER_APP0 | \
>>>>> V4L2_JPEG_ACTIVE_MARKER_COM | \
>>>>> V4L2_JPEG_ACTIVE_MARKER_DQT | \
>>>>> @@ -487,18 +463,6 @@ static const struct hantro_ctrl controls[] = {
>>>>> .cfg = {
>>>>> .id = V4L2_CID_STATELESS_HEVC_SCALING_MATRIX,
>>>>> },
>>>>> - }, {
>>>>> - .codec = HANTRO_HEVC_DECODER,
>>>>> - .cfg = {
>>>>> - .id = V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP,
>>>>> - .name = "Hantro HEVC slice header skip bytes",
>>>>> - .type = V4L2_CTRL_TYPE_INTEGER,
>>>>> - .min = 0,
>>>>> - .def = 0,
>>>>> - .max = 0x100,
>>>>> - .step = 1,
>>>>> - .ops = &hantro_hevc_ctrl_ops,
>>>>> - },
>>>>> }, {
>>>>> .codec = HANTRO_VP9_DECODER,
>>>>> .cfg = {
>>>>> diff --git a/drivers/staging/media/hantro/hantro_g2_hevc_dec.c b/drivers/staging/media/hantro/hantro_g2_hevc_dec.c
>>>>> index d28653d04d20..3be8d6e60bf0 100644
>>>>> --- a/drivers/staging/media/hantro/hantro_g2_hevc_dec.c
>>>>> +++ b/drivers/staging/media/hantro/hantro_g2_hevc_dec.c
>>>>> @@ -117,6 +117,66 @@ static void prepare_tile_info_buffer(struct hantro_ctx *ctx)
>>>>> vpu_debug(1, "%s: no chroma!\n", __func__);
>>>>> }
>>>>>
>>>>> +static unsigned int ceil_log2(unsigned int v)
>>>>> +{
>>>>> + /* Compute Ceil(Log2(v))
>>>>> + * Derived from branchless code for integer log2(v) from:
>>>>> + * <http://graphics.stanford.edu/~seander/bithacks.html#IntegerLog>
>>>>> + */
>>>>> + unsigned int r, shift;
>>>>> +
>>>>> + v--;
>>>>> + r = (v > 0xFFFF) << 4;
>>>>> + v >>= r;
>>>>> + shift = (v > 0xFF) << 3;
>>>>> + v >>= shift;
>>>>> + r |= shift;
>>>>> + shift = (v > 0xF) << 2;
>>>>> + v >>= shift;
>>>>> + r |= shift;
>>>>> + shift = (v > 0x3) << 1;
>>>>> + v >>= shift;
>>>>> + r |= shift;
>>>>> + r |= (v >> 1);
>>>>> +
>>>>> + return r + 1;
>>>>> +}
>>>> Isn't this identical to fls(v - 1)? See also lib/math/reciprocal_div.c
>>>> where this is used.
>>> Thanks for pointing this out, I was wondering if there was an equivalent, and
>>> never knew there was a relation between log2() and the "last set bit". Not sure
>>> about the -1 here though, can you extend ?
>> Based on how lib/math/reciprocal_div.c did it. Also, the ceil_log2 function
>> starts with v--, while fls doesn't. That said, it's wise to verify that that
>> is correct.
> Just for the reference, from lib/math/reciprocal_div.c:
>
> /* ceil(log2(d)) */
> l = fls(d - 1);
>
> Perhaps fls() return position starting from 1 rather then 0 ?

I have compare the results of ceil_log2(d) vs fls(d-1)
for values between 2 (because sps->num_short_term_ref_pic_sets > 1) and 16 (the maximum number of frames)
they are always the same so I will remove ceil_log2() and use fls().

Regards,
Benjamin

>
> Nicolas
>
>> Regards,
>>
>> Hans
>>
>>>> Regards,
>>>>
>>>> Hans
>>>>
>>>>> +
>>>>> +static int compute_header_skip_lenght(struct hantro_ctx *ctx)
>>>>> +{
>>>>> + const struct hantro_hevc_dec_ctrls *ctrls = &ctx->hevc_dec.ctrls;
>>>>> + const struct v4l2_ctrl_hevc_decode_params *decode_params = ctrls->decode_params;
>>>>> + const struct v4l2_ctrl_hevc_sps *sps = ctrls->sps;
>>>>> + const struct v4l2_ctrl_hevc_pps *pps = ctrls->pps;
>>>>> + int skip = 0;
>>>>> +
>>>>> + if (pps->flags & V4L2_HEVC_PPS_FLAG_OUTPUT_FLAG_PRESENT)
>>>>> + /* size of pic_output_flag */
>>>>> + skip++;
>>>>> +
>>>>> + if (sps->flags & V4L2_HEVC_SPS_FLAG_SEPARATE_COLOUR_PLANE)
>>>>> + /* size of pic_order_cnt_lsb */
>>>>> + skip += 2;
>>>>> +
>>>>> + if (!(decode_params->flags & V4L2_HEVC_DECODE_PARAM_FLAG_IDR_PIC)) {
>>>>> + /* size of pic_order_cnt_lsb */
>>>>> + skip += sps->log2_max_pic_order_cnt_lsb_minus4 + 4;
>>>>> +
>>>>> + /* size of short_term_ref_pic_set_sps_flag */
>>>>> + skip++;
>>>>> +
>>>>> + if (decode_params->short_term_ref_pic_set_size)
>>>>> + /* size of st_ref_pic_set( num_short_term_ref_pic_sets ) */
>>>>> + skip += decode_params->short_term_ref_pic_set_size;
>>>>> + else if (sps->num_short_term_ref_pic_sets > 1)
>>>>> + skip += ceil_log2(sps->num_short_term_ref_pic_sets);
>>>>> +
>>>>> + skip += decode_params->long_term_ref_pic_set_size;
>>>>> + }
>>>>> +
>>>>> + return skip;
>>>>> +}
>>>>> +
>>>>> static void set_params(struct hantro_ctx *ctx)
>>>>> {
>>>>> const struct hantro_hevc_dec_ctrls *ctrls = &ctx->hevc_dec.ctrls;
>>>>> @@ -134,7 +194,7 @@ static void set_params(struct hantro_ctx *ctx)
>>>>>
>>>>> hantro_reg_write(vpu, &g2_output_8_bits, 0);
>>>>>
>>>>> - hantro_reg_write(vpu, &g2_hdr_skip_length, ctrls->hevc_hdr_skip_length);
>>>>> + hantro_reg_write(vpu, &g2_hdr_skip_length, compute_header_skip_lenght(ctx));
>>>>>
>>>>> min_log2_cb_size = sps->log2_min_luma_coding_block_size_minus3 + 3;
>>>>> max_log2_ctb_size = min_log2_cb_size + sps->log2_diff_max_min_luma_coding_block_size;
>>>>> diff --git a/include/media/hevc-ctrls.h b/include/media/hevc-ctrls.h
>>>>> index d6cb3779d190..efc0412ac41e 100644
>>>>> --- a/include/media/hevc-ctrls.h
>>>>> +++ b/include/media/hevc-ctrls.h
>>>>> @@ -467,17 +467,4 @@ struct v4l2_ctrl_hevc_scaling_matrix {
>>>>> __u8 scaling_list_dc_coef_32x32[2];
>>>>> };
>>>>>
>>>>> -/* MPEG-class control IDs specific to the Hantro driver as defined by V4L2 */
>>>>> -#define V4L2_CID_CODEC_HANTRO_BASE (V4L2_CTRL_CLASS_CODEC | 0x1200)
>>>>> -/*
>>>>> - * V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP -
>>>>> - * the number of data (in bits) to skip in the
>>>>> - * slice segment header.
>>>>> - * If non-IDR, the bits to be skipped go from syntax element "pic_output_flag"
>>>>> - * to before syntax element "slice_temporal_mvp_enabled_flag".
>>>>> - * If IDR, the skipped bits are just "pic_output_flag"
>>>>> - * (separate_colour_plane_flag is not supported).
>>>>> - */
>>>>> -#define V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP (V4L2_CID_CODEC_HANTRO_BASE + 0)
>>>>> -
>>>>> #endif