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

From: Dmitry Baryshkov
Date: Fri Dec 01 2023 - 03:39:38 EST

On Fri, 1 Dec 2023 at 01:50, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:
>
>
>
> On 8/30/2023 5:06 PM, Dmitry Baryshkov wrote:
> > 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.
> >
>
> Yes but even that one CDM block can be used by any connector. So as we
> discussed on IRC, this just implements the FCFS and we need RM to be the
> manager of that one block.

Yes. "almost"

>
> >>
> >> 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.
> >
>
> hmmm ... ok with a pinch of salt as we somewhat deviate from the true
> topology definition that topology is just how lm, dsc and intf blocks
> are used. it was not intended to hold cdm.

Why not? I mean it is more logical compared to adding the 'needs_cdm'
argument which gets passed through together with the topology.

>
> >> {
> >> 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