[PATCH] drm/amd/powerplay: Protect backend resource when unload driver

[Jesse Zhang]

Guest driver can be unloaded while engines still using some backend resources
which whould lead to guest driver unload failure.

Need to add mutex lock to protect backend resources from concurrent operations

Before entering powergating mode, VCE and UVD need to check if backend
resources are still available.

Change-Id: Icc34f93818743856c4efbbbf9480e4d9f2e0d1e1
Signed-off-by: Jesse Zhang <zhexi.zhang at amd.com>
---
 drivers/gpu/drm/amd/powerplay/amd_powerplay.c      | 4 ++++
 drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/amd/powerplay/amd_powerplay.c b/drivers/gpu/drm/amd/powerplay/amd_powerplay.c
index 0314476..c82570b 100644
--- a/drivers/gpu/drm/amd/powerplay/amd_powerplay.c
+++ b/drivers/gpu/drm/amd/powerplay/amd_powerplay.c
@@ -134,7 +134,9 @@ static int pp_hw_fini(void *handle)
 	struct amdgpu_device *adev = handle;
 	struct pp_hwmgr *hwmgr = adev->powerplay.pp_handle;
 
+	mutex_lock(&hwmgr->smu_lock);
 	hwmgr_hw_fini(hwmgr);
+	mutex_unlock(&hwmgr->smu_lock);
 
 	return 0;
 }
@@ -662,7 +664,9 @@ static int amd_powerplay_reset(void *handle)
 	struct pp_hwmgr *hwmgr = handle;
 	int ret;
 
+	mutex_lock(&hwmgr->smu_lock);
 	ret = hwmgr_hw_fini(hwmgr);
+	mutex_unlock(&hwmgr->smu_lock);
 	if (ret)
 		return ret;
 
diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
index 46538233..f72ba70 100644
--- a/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
@@ -4616,6 +4616,9 @@ static void vega10_power_gate_vce(struct pp_hwmgr *hwmgr, bool bgate)
 {
 	struct vega10_hwmgr *data = hwmgr->backend;
 
+	if (!data)
+		return;
+
 	data->vce_power_gated = bgate;
 	vega10_enable_disable_vce_dpm(hwmgr, !bgate);
 }
@@ -4624,6 +4627,9 @@ static void vega10_power_gate_uvd(struct pp_hwmgr *hwmgr, bool bgate)
 {
 	struct vega10_hwmgr *data = hwmgr->backend;
 
+	if (!data)
+		return;
+
 	data->uvd_power_gated = bgate;
 	vega10_enable_disable_uvd_dpm(hwmgr, !bgate);
 }
-- 
2.7.4