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References: <20220706182657.210650-1-ezequiel@vanguardiasur.com.ar> <20220706182657.210650-7-ezequiel@vanguardiasur.com.ar>
In-Reply-To: <20220706182657.210650-7-ezequiel@vanguardiasur.com.ar>
From:   Tomasz Figa <tfiga@chromium.org>
Date:   Fri, 8 Jul 2022 13:40:53 +0900
Message-ID: <CAAFQd5BSDnZ6MyXfcRWNM9f9WF82sjPX3F1ZjYjcOuz3b1fPkw@mail.gmail.com>
Subject: Re: [PATCH 6/8] rkvdec: Use vb2_find_buffer
To:     Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Cc:     linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Marek Szyprowski <m.szyprowski@samsung.com>
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Precedence: bulk

Hi Ezequiel,

On Thu, Jul 7, 2022 at 3:27 AM Ezequiel Garcia
<ezequiel@vanguardiasur.com.ar> wrote:
>
> Use the newly introduced vb2_find_buffer API to get a vb2_buffer
> given a buffer timestamp.
>
> Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
> ---
>  drivers/staging/media/rkvdec/rkvdec-h264.c | 41 ++++++++--------------
>  drivers/staging/media/rkvdec/rkvdec-vp9.c  | 10 +++---
>  2 files changed, 19 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/staging/media/rkvdec/rkvdec-h264.c b/drivers/staging/media/rkvdec/rkvdec-h264.c
> index 2992fb87cf72..4af5a831bde0 100644
> --- a/drivers/staging/media/rkvdec/rkvdec-h264.c
> +++ b/drivers/staging/media/rkvdec/rkvdec-h264.c
> @@ -109,7 +109,7 @@ struct rkvdec_h264_run {
>         const struct v4l2_ctrl_h264_sps *sps;
>         const struct v4l2_ctrl_h264_pps *pps;
>         const struct v4l2_ctrl_h264_scaling_matrix *scaling_matrix;
> -       int ref_buf_idx[V4L2_H264_NUM_DPB_ENTRIES];
> +       struct vb2_buffer *ref_buf[V4L2_H264_NUM_DPB_ENTRIES];

How do we guarantee that those pointers remain valid through the
lifetime of this structure?

Best regards,
Tomasz

>  };
>
>  struct rkvdec_h264_ctx {
> @@ -742,17 +742,16 @@ static void lookup_ref_buf_idx(struct rkvdec_ctx *ctx,
>                 struct v4l2_m2m_ctx *m2m_ctx = ctx->fh.m2m_ctx;
>                 const struct v4l2_h264_dpb_entry *dpb = run->decode_params->dpb;
>                 struct vb2_queue *cap_q = &m2m_ctx->cap_q_ctx.q;
> -               int buf_idx = -1;
> +               struct vb2_buffer *buf = NULL;
>
>                 if (dpb[i].flags & V4L2_H264_DPB_ENTRY_FLAG_ACTIVE) {
> -                       buf_idx = vb2_find_timestamp(cap_q,
> -                                                    dpb[i].reference_ts, 0);
> -                       if (buf_idx < 0)
> +                       buf = vb2_find_buffer(cap_q, dpb[i].reference_ts);
> +                       if (!buf)
>                                 pr_debug("No buffer for reference_ts %llu",
>                                          dpb[i].reference_ts);
>                 }
>
> -               run->ref_buf_idx[i] = buf_idx;
> +               run->ref_buf[i] = buf;
>         }
>  }
>
> @@ -805,7 +804,7 @@ static void assemble_hw_rps(struct rkvdec_ctx *ctx,
>                         if (WARN_ON(ref->index >= ARRAY_SIZE(dec_params->dpb)))
>                                 continue;
>
> -                       dpb_valid = run->ref_buf_idx[ref->index] >= 0;
> +                       dpb_valid = run->ref_buf[ref->index] != NULL;
>                         bottom = ref->fields == V4L2_H264_BOTTOM_FIELD_REF;
>
>                         set_ps_field(hw_rps, DPB_INFO(i, j),
> @@ -881,24 +880,6 @@ static const u32 poc_reg_tbl_bottom_field[16] = {
>         RKVDEC_REG_H264_POC_REFER2(1)
>  };
>
> -static struct vb2_buffer *
> -get_ref_buf(struct rkvdec_ctx *ctx, struct rkvdec_h264_run *run,
> -           unsigned int dpb_idx)
> -{
> -       struct v4l2_m2m_ctx *m2m_ctx = ctx->fh.m2m_ctx;
> -       struct vb2_queue *cap_q = &m2m_ctx->cap_q_ctx.q;
> -       int buf_idx = run->ref_buf_idx[dpb_idx];
> -
> -       /*
> -        * If a DPB entry is unused or invalid, address of current destination
> -        * buffer is returned.
> -        */
> -       if (buf_idx < 0)
> -               return &run->base.bufs.dst->vb2_buf;
> -
> -       return vb2_get_buffer(cap_q, buf_idx);
> -}
> -
>  static void config_registers(struct rkvdec_ctx *ctx,
>                              struct rkvdec_h264_run *run)
>  {
> @@ -971,8 +952,14 @@ static void config_registers(struct rkvdec_ctx *ctx,
>
>         /* config ref pic address & poc */
>         for (i = 0; i < ARRAY_SIZE(dec_params->dpb); i++) {
> -               struct vb2_buffer *vb_buf = get_ref_buf(ctx, run, i);
> -
> +               struct vb2_buffer *vb_buf = run->ref_buf[i];
> +
> +               /*
> +                * If a DPB entry is unused or invalid, address of current destination
> +                * buffer is returned.
> +                */
> +               if (!vb_buf)
> +                       vb_buf = &dst_buf->vb2_buf;
>                 refer_addr = vb2_dma_contig_plane_dma_addr(vb_buf, 0);
>
>                 if (dpb[i].flags & V4L2_H264_DPB_ENTRY_FLAG_ACTIVE)
> diff --git a/drivers/staging/media/rkvdec/rkvdec-vp9.c b/drivers/staging/media/rkvdec/rkvdec-vp9.c
> index c2f42e76be10..d8c1c0db15c7 100644
> --- a/drivers/staging/media/rkvdec/rkvdec-vp9.c
> +++ b/drivers/staging/media/rkvdec/rkvdec-vp9.c
> @@ -383,17 +383,17 @@ get_ref_buf(struct rkvdec_ctx *ctx, struct vb2_v4l2_buffer *dst, u64 timestamp)
>  {
>         struct v4l2_m2m_ctx *m2m_ctx = ctx->fh.m2m_ctx;
>         struct vb2_queue *cap_q = &m2m_ctx->cap_q_ctx.q;
> -       int buf_idx;
> +       struct vb2_buffer *buf;
>
>         /*
>          * If a ref is unused or invalid, address of current destination
>          * buffer is returned.
>          */
> -       buf_idx = vb2_find_timestamp(cap_q, timestamp, 0);
> -       if (buf_idx < 0)
> -               return vb2_to_rkvdec_decoded_buf(&dst->vb2_buf);
> +       buf = vb2_find_buffer(cap_q, timestamp);
> +       if (!buf)
> +               buf = &dst->vb2_buf;
>
> -       return vb2_to_rkvdec_decoded_buf(vb2_get_buffer(cap_q, buf_idx));
> +       return vb2_to_rkvdec_decoded_buf(buf);
>  }
>
>  static dma_addr_t get_mv_base_addr(struct rkvdec_decoded_buffer *buf)
> --
> 2.34.3
>