drm/amd/powerplay: add sensor lock support for smu

when multithreading access sysfs of amdgpu_pm_info at the sametime.
the swsmu driver cause smu firmware hang.

eg:
single thread access:
Message A + Param A ==> right
Message B + Param B ==> right
Message C + Param C ==> right
multithreading access:
Message A + Param B ==> error
Message B + Param A ==> error
Message C + Param C ==> right

the patch will add sensor lock(mutex) to avoid this error.
Signed-off-by: Kevin Wang <kevin1.wang@amd.com>
Reviewed-by: Kenneth Feng <kenneth.feng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org # 5.3.x

drivers/gpu/drm/amd/powerplay/amdgpu_smu.c

@@ -843,6 +843,8 @@ static int smu_sw_init(void *handle)
 	smu->smu_baco.state = SMU_BACO_STATE_EXIT;
 	smu->smu_baco.platform_support = false;
 
+	mutex_init(&smu->sensor_lock);
+
 	smu->watermarks_bitmap = 0;
 	smu->power_profile_mode = PP_SMC_POWER_PROFILE_BOOTUP_DEFAULT;
 	smu->default_power_profile_mode = PP_SMC_POWER_PROFILE_BOOTUP_DEFAULT;

drivers/gpu/drm/amd/powerplay/arcturus_ppt.c

@@ -1018,6 +1018,7 @@ static int arcturus_read_sensor(struct smu_context *smu,
 	if (!data || !size)
 		return -EINVAL;
 
+	mutex_lock(&smu->sensor_lock);
 	switch (sensor) {
 	case AMDGPU_PP_SENSOR_MAX_FAN_RPM:
 		*(uint32_t *)data = pptable->FanMaximumRpm;
@@ -1044,6 +1045,7 @@ static int arcturus_read_sensor(struct smu_context *smu,
 	default:
 		ret = smu_smc_read_sensor(smu, sensor, data, size);
 	}
+	mutex_unlock(&smu->sensor_lock);
 
 	return ret;
 }

drivers/gpu/drm/amd/powerplay/inc/amdgpu_smu.h

@@ -344,6 +344,7 @@ struct smu_context
 	const struct smu_funcs		*funcs;
 	const struct pptable_funcs	*ppt_funcs;
 	struct mutex			mutex;
+	struct mutex			sensor_lock;
 	uint64_t pool_size;
 
 	struct smu_table_context	smu_table;

drivers/gpu/drm/amd/powerplay/navi10_ppt.c

@@ -1386,6 +1386,7 @@ static int navi10_read_sensor(struct smu_context *smu,
 	if(!data || !size)
 		return -EINVAL;
 
+	mutex_lock(&smu->sensor_lock);
 	switch (sensor) {
 	case AMDGPU_PP_SENSOR_MAX_FAN_RPM:
 		*(uint32_t *)data = pptable->FanMaximumRpm;
@@ -1409,6 +1410,7 @@ static int navi10_read_sensor(struct smu_context *smu,
 	default:
 		ret = smu_smc_read_sensor(smu, sensor, data, size);
 	}
+	mutex_unlock(&smu->sensor_lock);
 
 	return ret;
 }

drivers/gpu/drm/amd/powerplay/vega20_ppt.c

@@ -3023,6 +3023,7 @@ static int vega20_read_sensor(struct smu_context *smu,
 	if(!data || !size)
 		return -EINVAL;
 
+	mutex_lock(&smu->sensor_lock);
 	switch (sensor) {
 	case AMDGPU_PP_SENSOR_MAX_FAN_RPM:
 		*(uint32_t *)data = pptable->FanMaximumRpm;
@@ -3048,6 +3049,7 @@ static int vega20_read_sensor(struct smu_context *smu,
 	default:
 		ret = smu_smc_read_sensor(smu, sensor, data, size);
 	}
+	mutex_unlock(&smu->sensor_lock);
 
 	return ret;
 }