Re: [PATCH 08/16] drm/msm/dpu: add support to allocate CDM from RM

[Dmitry Baryshkov]

On Thu, 31 Aug 2023 at 01:50, 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.

It almost feels like an overkill, as up to now there is at most one CDM block.

>
> Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c |  2 +-
>  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      | 45 +++++++++++++++++++--
>  drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h      |  4 +-
>  5 files changed, 48 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index 6cf6597148fd..582680804016 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -663,7 +663,7 @@ static int dpu_encoder_virt_atomic_check(
>
>                 if (!crtc_state->active_changed || crtc_state->enable)
>                         ret = dpu_rm_reserve(&dpu_kms->rm, global_state,
> -                                       drm_enc, crtc_state, topology);
> +                                       drm_enc, crtc_state, topology, false);
>         }
>
>         trace_dpu_enc_atomic_check_flags(DRMID(drm_enc), adj_mode->flags);
> 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 34f943102499..07f75f295844 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 b6f53ca6e962..61aa58643fda 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> @@ -136,6 +136,7 @@ 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 7b6444a3fcb1..e7d4beb4661e 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
> @@ -29,10 +29,12 @@ static inline bool reserved_by_other(uint32_t *res_map, int idx,
>  /**
>   * struct dpu_rm_requirements - Reservation requirements parameter bundle
>   * @topology:  selected topology for the display
> + * @needs_cdm: whether the display needs a CDM block for the current mode
>   * @hw_res:       Hardware resources required as reported by the encoders
>   */
>  struct dpu_rm_requirements {
>         struct msm_display_topology topology;
> +       bool needs_cdm;
>  };
>
>  int dpu_rm_destroy(struct dpu_rm *rm)
> @@ -505,6 +507,26 @@ 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");
> +               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,
> @@ -530,15 +552,25 @@ static int _dpu_rm_make_reservation(
>         if (ret)
>                 return ret;
>
> +       if (reqs->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;
>  }
>
>  static int _dpu_rm_populate_requirements(
>                 struct drm_encoder *enc,
>                 struct dpu_rm_requirements *reqs,
> -               struct msm_display_topology req_topology)
> +               struct msm_display_topology req_topology,
> +               bool needs_cdm)

Push it to the topology, please. It is a part of the topology at some
point of view.

>  {
>         reqs->topology = req_topology;
> +       reqs->needs_cdm = needs_cdm;
>
>         DRM_DEBUG_KMS("num_lm: %d num_dsc: %d num_intf: %d\n",
>                       reqs->topology.num_lm, reqs->topology.num_dsc,
> @@ -571,6 +603,7 @@ 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(
> @@ -578,7 +611,8 @@ int dpu_rm_reserve(
>                 struct dpu_global_state *global_state,
>                 struct drm_encoder *enc,
>                 struct drm_crtc_state *crtc_state,
> -               struct msm_display_topology topology)
> +               struct msm_display_topology topology,
> +               bool needs_cdm)
>  {
>         struct dpu_rm_requirements reqs;
>         int ret;
> @@ -595,7 +629,7 @@ int dpu_rm_reserve(
>         DRM_DEBUG_KMS("reserving hw for enc %d crtc %d\n",
>                       enc->base.id, crtc_state->crtc->base.id);
>
> -       ret = _dpu_rm_populate_requirements(enc, &reqs, topology);
> +       ret = _dpu_rm_populate_requirements(enc, &reqs, topology, needs_cdm);
>         if (ret) {
>                 DPU_ERROR("failed to populate hw requirements\n");
>                 return ret;
> @@ -644,6 +678,11 @@ 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/disp/dpu1/dpu_rm.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h
> index 29b221491926..74262d3cb6c3 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h
> @@ -69,13 +69,15 @@ int dpu_rm_destroy(struct dpu_rm *rm);
>   * @drm_enc: DRM Encoder handle
>   * @crtc_state: Proposed Atomic DRM CRTC State handle
>   * @topology: Pointer to topology info for the display
> + * @needs_cdm: bool to indicate whether current encoder needs CDM
>   * @Return: 0 on Success otherwise -ERROR
>   */
>  int dpu_rm_reserve(struct dpu_rm *rm,
>                 struct dpu_global_state *global_state,
>                 struct drm_encoder *drm_enc,
>                 struct drm_crtc_state *crtc_state,
> -               struct msm_display_topology topology);
> +               struct msm_display_topology topology,
> +               bool needs_cdm);
>
>  /**
>   * dpu_rm_reserve - Given the encoder for the display chain, release any
> --
> 2.40.1
>


-- 
With best wishes
Dmitry