drm/msm/dpu: add support to allocate CDM from RM

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@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/571827/
Link: https://lore.kernel.org/r/20231212205254.12422-10-quic_abhinavk@quicinc.comSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

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,
 };
 

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

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");
+		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;

drivers/gpu/drm/msm/msm_drv.h

@@ -90,12 +90,14 @@ 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 */