drm/msm/dpu: add support for MDP_TOP blackhole

On sm8450 a register block was removed from MDP TOP. Accessing it during
snapshotting results in NoC errors / immediate reboot. Skip accessing
these registers during snapshot.
Tested-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/514239/
Link: https://lore.kernel.org/r/20221207012231.112059-10-dmitry.baryshkov@linaro.orgSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h

@@ -83,6 +83,8 @@ enum {
  * @DPU_MDP_UBWC_1_0,      This chipsets supports Universal Bandwidth
  *                         compression initial revision
  * @DPU_MDP_UBWC_1_5,      Universal Bandwidth compression version 1.5
+ * @DPU_MDP_PERIPH_0_REMOVED Indicates that access to periph top0 block results
+ *			   in a failure
  * @DPU_MDP_MAX            Maximum value
 
  */
@@ -93,6 +95,7 @@ enum {
 	DPU_MDP_UBWC_1_0,
 	DPU_MDP_UBWC_1_5,
 	DPU_MDP_AUDIO_SELECT,
+	DPU_MDP_PERIPH_0_REMOVED,
 	DPU_MDP_MAX
 };
 

drivers/gpu/drm/msm/disp/dpu1/dpu_hwio.h

@@ -63,4 +63,7 @@
 #define MDP_WD_TIMER_4_LOAD_VALUE       0x448
 #define DCE_SEL                         0x450
 
+#define MDP_PERIPH_TOP0			MDP_WD_TIMER_0_CTL
+#define MDP_PERIPH_TOP0_END		CLK_CTRL3
+
 #endif /*_DPU_HWIO_H */

drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c

@@ -927,8 +927,15 @@ static void dpu_kms_mdp_snapshot(struct msm_disp_state *disp_state, struct msm_k
 		msm_disp_snapshot_add_block(disp_state, cat->wb[i].len,
 				dpu_kms->mmio + cat->wb[i].base, "wb_%d", i);
 
+	if (cat->mdp[0].features & BIT(DPU_MDP_PERIPH_0_REMOVED)) {
+		msm_disp_snapshot_add_block(disp_state, MDP_PERIPH_TOP0,
+				dpu_kms->mmio + cat->mdp[0].base, "top");
+		msm_disp_snapshot_add_block(disp_state, cat->mdp[0].len - MDP_PERIPH_TOP0_END,
+				dpu_kms->mmio + cat->mdp[0].base + MDP_PERIPH_TOP0_END, "top_2");
+	} else {
 		msm_disp_snapshot_add_block(disp_state, cat->mdp[0].len,
 				dpu_kms->mmio + cat->mdp[0].base, "top");
+	}
 
 	pm_runtime_put_sync(&dpu_kms->pdev->dev);
 }