[PATCH] drm/amdgpu: correct the wrong cached state for GMC on PICASSO

[Evan Quan]

Pair the operations did in GMC ->hw_init and ->hw_fini. That
can help to maintain correct cached state for GMC and avoid
unintention gate operation dropping due to wrong cached state.

BUG: https://gitlab.freedesktop.org/drm/amd/-/issues/1828

Signed-off-by: Evan Quan <evan.quan at amd.com>
Change-Id: I9976672a64464b86bb45eed0c25c9599d3bb4c06
---
 drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c            | 8 ++++++++
 drivers/gpu/drm/amd/amdgpu/mmhub_v1_0.c          | 8 ++++----
 drivers/gpu/drm/amd/pm/powerplay/amd_powerplay.c | 7 ++++++-
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
index db2ec84f7237..c7492db3e189 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
@@ -1809,6 +1809,14 @@ static int gmc_v9_0_hw_fini(void *handle)
 		return 0;
 	}
 
+	/*
+	 * Pair the operations did in gmc_v9_0_hw_init and thus maintain
+	 * a correct cached state for GMC. Otherwise, the "gate" again
+	 * operation on S3 resuming will fail due to wrong cached state.
+	 */
+	if (adev->mmhub.funcs->update_power_gating)
+		adev->mmhub.funcs->update_power_gating(adev, false);
+
 	amdgpu_irq_put(adev, &adev->gmc.ecc_irq, 0);
 	amdgpu_irq_put(adev, &adev->gmc.vm_fault, 0);
 
diff --git a/drivers/gpu/drm/amd/amdgpu/mmhub_v1_0.c b/drivers/gpu/drm/amd/amdgpu/mmhub_v1_0.c
index b3bede1dc41d..1da2ec692057 100644
--- a/drivers/gpu/drm/amd/amdgpu/mmhub_v1_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/mmhub_v1_0.c
@@ -301,10 +301,10 @@ static void mmhub_v1_0_update_power_gating(struct amdgpu_device *adev,
 	if (amdgpu_sriov_vf(adev))
 		return;
 
-	if (enable && adev->pg_flags & AMD_PG_SUPPORT_MMHUB) {
-		amdgpu_dpm_set_powergating_by_smu(adev, AMD_IP_BLOCK_TYPE_GMC, true);
-
-	}
+	if (adev->pg_flags & AMD_PG_SUPPORT_MMHUB)
+		amdgpu_dpm_set_powergating_by_smu(adev,
+						  AMD_IP_BLOCK_TYPE_GMC,
+						  enable);
 }
 
 static int mmhub_v1_0_gart_enable(struct amdgpu_device *adev)
diff --git a/drivers/gpu/drm/amd/pm/powerplay/amd_powerplay.c b/drivers/gpu/drm/amd/pm/powerplay/amd_powerplay.c
index 3656a77baea4..9953a77cb987 100644
--- a/drivers/gpu/drm/amd/pm/powerplay/amd_powerplay.c
+++ b/drivers/gpu/drm/amd/pm/powerplay/amd_powerplay.c
@@ -1167,7 +1167,12 @@ static int pp_set_powergating_by_smu(void *handle,
 		pp_dpm_powergate_vce(handle, gate);
 		break;
 	case AMD_IP_BLOCK_TYPE_GMC:
-		pp_dpm_powergate_mmhub(handle);
+		/*
+		 * For now, this is only used on PICASSO.
+		 * And only "gate" operation is supported.
+		 */
+		if (gate)
+			pp_dpm_powergate_mmhub(handle);
 		break;
 	case AMD_IP_BLOCK_TYPE_GFX:
 		ret = pp_dpm_powergate_gfx(handle, gate);
-- 
2.29.0