[PATCH 07/21] drm/msm/dpu: Check CRTC encoders are valid clones

[Jessica Zhang]

Check that each encoder in the CRTC state's encoder_mask is marked as a
possible clone for all other encoders in the encoder_mask and that only
one CRTC is in clone mode at a time

Signed-off-by: Jessica Zhang <quic_jesszhan at quicinc.com>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 36 +++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
index 5ec1b5a38922..bebae365c036 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ * Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All rights reserved.
  * Copyright (c) 2014-2021 The Linux Foundation. All rights reserved.
  * Copyright (C) 2013 Red Hat
  * Author: Rob Clark <robdclark at gmail.com>
@@ -1204,6 +1204,36 @@ static struct msm_display_topology dpu_crtc_get_topology(
 	return topology;
 }
 
+static bool dpu_crtc_has_valid_clones(struct drm_crtc *crtc,
+		struct drm_crtc_state *crtc_state)
+{
+	struct drm_encoder *drm_enc;
+	struct drm_crtc *temp_crtc;
+	int num_cwb_sessions = 0;
+
+	drm_for_each_crtc(temp_crtc, crtc->dev)
+		if (drm_crtc_in_clone_mode(temp_crtc->state))
+			num_cwb_sessions++;
+
+	/*
+	 * Only support a single concurrent writeback session running
+	 * at a time
+	 */
+	if (num_cwb_sessions > 1)
+		return false;
+
+	drm_for_each_encoder_mask(drm_enc, crtc->dev, crtc_state->encoder_mask) {
+		if ((crtc_state->encoder_mask & drm_enc->possible_clones) !=
+				crtc_state->encoder_mask) {
+			DPU_ERROR("crtc%d failed valid clone check for mask 0x%x\n",
+				crtc->base.id, crtc_state->encoder_mask);
+			return false;
+		}
+	}
+
+	return true;
+}
+
 static int dpu_crtc_assign_resources(struct drm_crtc *crtc, struct drm_crtc_state *crtc_state)
 {
 	struct dpu_hw_blk *hw_ctl[MAX_CHANNELS_PER_CRTC];
@@ -1287,6 +1317,10 @@ static int dpu_crtc_atomic_check(struct drm_crtc *crtc,
 			return rc;
 	}
 
+	if (drm_crtc_in_clone_mode(crtc_state) &&
+			!dpu_crtc_has_valid_clones(crtc, crtc_state))
+		return -EINVAL;
+
 	if (!crtc_state->enable || !drm_atomic_crtc_effectively_active(crtc_state)) {
 		DRM_DEBUG_ATOMIC("crtc%d -> enable %d, active %d, skip atomic_check\n",
 				crtc->base.id, crtc_state->enable,

-- 
2.34.1