Re: [PATCH v2 09/16] drm/msm/dpu: add support to allocate CDM from RM

[Dmitry Baryshkov]

On Fri, 8 Dec 2023 at 07:07, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:
>
> Even though there is usually only one CDM block, it can be
> used by either HDMI, DisplayPort OR Writeback interfaces.
>
> Hence its allocation needs to be tracked properly by the
> resource manager to ensure appropriate availability of the
> block.
>
> changes in v2:
>         - move needs_cdm to topology struct
>
> Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_mdss.h |  1 +
>  drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h     |  1 +
>  drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c      | 38 +++++++++++++++++++--
>  drivers/gpu/drm/msm/msm_drv.h               |  2 ++
>  4 files changed, 40 insertions(+), 2 deletions(-)

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>

>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_mdss.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_mdss.h
> index 9db4cf61bd29..5df545904057 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_mdss.h
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_mdss.h
> @@ -98,6 +98,7 @@ enum dpu_hw_blk_type {
>         DPU_HW_BLK_DSPP,
>         DPU_HW_BLK_MERGE_3D,
>         DPU_HW_BLK_DSC,
> +       DPU_HW_BLK_CDM,
>         DPU_HW_BLK_MAX,
>  };
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> index df6271017b80..a0cd36e45a01 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> @@ -135,6 +135,7 @@ struct dpu_global_state {
>         uint32_t ctl_to_enc_id[CTL_MAX - CTL_0];
>         uint32_t dspp_to_enc_id[DSPP_MAX - DSPP_0];
>         uint32_t dsc_to_enc_id[DSC_MAX - DSC_0];
> +       uint32_t cdm_to_enc_id;
>  };
>
>  struct dpu_global_state
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
> index 7ed476b96304..b58a9c2ae326 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
> @@ -435,6 +435,26 @@ static int _dpu_rm_reserve_dsc(struct dpu_rm *rm,
>         return 0;
>  }
>
> +static int _dpu_rm_reserve_cdm(struct dpu_rm *rm,
> +                              struct dpu_global_state *global_state,
> +                              struct drm_encoder *enc)
> +{
> +       /* try allocating only one CDM block */
> +       if (!rm->cdm_blk) {
> +               DPU_ERROR("CDM block does not exist\n");

Nit: maybe this should be an info or a warning instead?

> +               return -EIO;
> +       }
> +
> +       if (global_state->cdm_to_enc_id) {
> +               DPU_ERROR("CDM_0 is already allocated\n");
> +               return -EIO;
> +       }
> +
> +       global_state->cdm_to_enc_id = enc->base.id;
> +
> +       return 0;
> +}
> +
>  static int _dpu_rm_make_reservation(
>                 struct dpu_rm *rm,
>                 struct dpu_global_state *global_state,
> @@ -460,6 +480,14 @@ static int _dpu_rm_make_reservation(
>         if (ret)
>                 return ret;
>
> +       if (reqs->topology.needs_cdm) {
> +               ret = _dpu_rm_reserve_cdm(rm, global_state, enc);
> +               if (ret) {
> +                       DPU_ERROR("unable to find CDM blk\n");
> +                       return ret;
> +               }
> +       }
> +
>         return ret;
>  }
>
> @@ -470,9 +498,9 @@ static int _dpu_rm_populate_requirements(
>  {
>         reqs->topology = req_topology;
>
> -       DRM_DEBUG_KMS("num_lm: %d num_dsc: %d num_intf: %d\n",
> +       DRM_DEBUG_KMS("num_lm: %d num_dsc: %d num_intf: %d cdm: %d\n",
>                       reqs->topology.num_lm, reqs->topology.num_dsc,
> -                     reqs->topology.num_intf);
> +                     reqs->topology.num_intf, reqs->topology.needs_cdm);
>
>         return 0;
>  }
> @@ -501,6 +529,7 @@ void dpu_rm_release(struct dpu_global_state *global_state,
>                 ARRAY_SIZE(global_state->dsc_to_enc_id), enc->base.id);
>         _dpu_rm_clear_mapping(global_state->dspp_to_enc_id,
>                 ARRAY_SIZE(global_state->dspp_to_enc_id), enc->base.id);
> +       _dpu_rm_clear_mapping(&global_state->cdm_to_enc_id, 1, enc->base.id);
>  }
>
>  int dpu_rm_reserve(
> @@ -574,6 +603,11 @@ int dpu_rm_get_assigned_resources(struct dpu_rm *rm,
>                 hw_to_enc_id = global_state->dsc_to_enc_id;
>                 max_blks = ARRAY_SIZE(rm->dsc_blks);
>                 break;
> +       case DPU_HW_BLK_CDM:
> +               hw_blks = &rm->cdm_blk;
> +               hw_to_enc_id = &global_state->cdm_to_enc_id;
> +               max_blks = 1;
> +               break;
>         default:
>                 DPU_ERROR("blk type %d not managed by rm\n", type);
>                 return 0;
> diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
> index a205127ccc93..1ebad634781c 100644
> --- a/drivers/gpu/drm/msm/msm_drv.h
> +++ b/drivers/gpu/drm/msm/msm_drv.h
> @@ -92,12 +92,14 @@ enum msm_event_wait {
>   * @num_intf:     number of interfaces the panel is mounted on
>   * @num_dspp:     number of dspp blocks used
>   * @num_dsc:      number of Display Stream Compression (DSC) blocks used
> + * @needs_cdm:    indicates whether cdm block is needed for this display topology
>   */
>  struct msm_display_topology {
>         u32 num_lm;
>         u32 num_intf;
>         u32 num_dspp;
>         u32 num_dsc;
> +       bool needs_cdm;
>  };
>
>  /* Commit/Event thread specific structure */
> --
> 2.40.1
>


-- 
With best wishes
Dmitry