drm/amdgpu/smu: Add message sending lock

This adds a message lock to the smu_send_smc_msg* implementations to
protect against concurrent access to the mmu registers used to
communicate with the SMU

v2: Implement for smu_v12_0 as well

v3: Add mutex_init for message_lock
Signed-off-by: Matt Coffin <mcoffin13@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -889,6 +889,7 @@ static int smu_sw_init(void *handle)
 
 	mutex_init(&smu->sensor_lock);
 	mutex_init(&smu->metrics_lock);
+	mutex_init(&smu->message_lock);
 
 	smu->watermarks_bitmap = 0;
 	smu->power_profile_mode = PP_SMC_POWER_PROFILE_BOOTUP_DEFAULT;

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

@@ -362,6 +362,7 @@ struct smu_context
 	struct mutex			mutex;
 	struct mutex			sensor_lock;
 	struct mutex			metrics_lock;
+	struct mutex			message_lock;
 	uint64_t pool_size;
 
 	struct smu_table_context	smu_table;

drivers/gpu/drm/amd/powerplay/smu_v11_0.c

@@ -102,11 +102,12 @@ smu_v11_0_send_msg_with_param(struct smu_context *smu,
 	if (index < 0)
 		return index;
 
+	mutex_lock(&smu->message_lock);
 	ret = smu_v11_0_wait_for_response(smu);
 	if (ret) {
 		pr_err("Msg issuing pre-check failed and "
 		       "SMU may be not in the right state!\n");
-		return ret;
+		goto out;
 	}
 
 	WREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_90, 0);
@@ -119,18 +120,19 @@ smu_v11_0_send_msg_with_param(struct smu_context *smu,
 	if (ret) {
 		pr_err("failed send message: %10s (%d) \tparam: 0x%08x response %#x\n",
 		       smu_get_message_name(smu, msg), index, param, ret);
-		return ret;
+		goto out;
 	}
 	if (read_arg) {
 		ret = smu_v11_0_read_arg(smu, read_arg);
 		if (ret) {
 			pr_err("failed to read message arg: %10s (%d) \tparam: 0x%08x response %#x\n",
 			       smu_get_message_name(smu, msg), index, param, ret);
-			return ret;
+			goto out;
 		}
 	}
-
-	return 0;
+out:
+	mutex_unlock(&smu->message_lock);
+	return ret;
 }
 
 int smu_v11_0_init_microcode(struct smu_context *smu)

drivers/gpu/drm/amd/powerplay/smu_v12_0.c

@@ -88,11 +88,12 @@ smu_v12_0_send_msg_with_param(struct smu_context *smu,
 	if (index < 0)
 		return index;
 
+	mutex_lock(&smu->message_lock);
 	ret = smu_v12_0_wait_for_response(smu);
 	if (ret) {
 		pr_err("Msg issuing pre-check failed and "
 		       "SMU may be not in the right state!\n");
-		return ret;
+		goto out;
 	}
 
 	WREG32_SOC15(MP1, 0, mmMP1_SMN_C2PMSG_90, 0);
@@ -105,17 +106,18 @@ smu_v12_0_send_msg_with_param(struct smu_context *smu,
 	if (ret) {
 		pr_err("Failed to send message 0x%x, response 0x%x param 0x%x\n",
 		       index, ret, param);
-		return ret;
+		goto out;
 	}
 	if (read_arg) {
 		ret = smu_v12_0_read_arg(smu, read_arg);
 		if (ret) {
 			pr_err("Failed to read message arg 0x%x, response 0x%x param 0x%x\n",
 			       index, ret, param);
-			return ret;
+			goto out;
 		}
 	}
-
+out:
+	mutex_unlock(&smu->message_lock);
 	return ret;
 }