drm/amd/pm: add flood detection for wbrf events

To protect PMFW from being overloaded.
Signed-off-by: Evan Quan <quanliangl@hotmail.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Ma Jun <Jun.Ma2@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c

@@ -1410,7 +1410,8 @@ static int smu_wbrf_event_handler(struct notifier_block *nb,
 
 	switch (action) {
 	case WBRF_CHANGED:
-		smu_wbrf_handle_exclusion_ranges(smu);
+		schedule_delayed_work(&smu->wbrf_delayed_work,
+				      msecs_to_jiffies(SMU_WBRF_EVENT_HANDLING_PACE));
 		break;
 	default:
 		return NOTIFY_DONE;
@@ -1419,6 +1420,20 @@ static int smu_wbrf_event_handler(struct notifier_block *nb,
 	return NOTIFY_OK;
 }
 
+/**
+ * smu_wbrf_delayed_work_handler - callback on delayed work timer expired
+ *
+ * @work: struct work_struct pointer
+ *
+ * Flood is over and driver will consume the latest exclusion ranges.
+ */
+static void smu_wbrf_delayed_work_handler(struct work_struct *work)
+{
+	struct smu_context *smu = container_of(work, struct smu_context, wbrf_delayed_work.work);
+
+	smu_wbrf_handle_exclusion_ranges(smu);
+}
+
 /**
  * smu_wbrf_support_check - check wbrf support
  *
@@ -1448,12 +1463,13 @@ static void smu_wbrf_support_check(struct smu_context *smu)
  */
 static int smu_wbrf_init(struct smu_context *smu)
 {
-	struct amdgpu_device *adev = smu->adev;
 	int ret;
 
 	if (!smu->wbrf_supported)
 		return 0;
 
+	INIT_DELAYED_WORK(&smu->wbrf_delayed_work, smu_wbrf_delayed_work_handler);
+
 	smu->wbrf_notifier.notifier_call = smu_wbrf_event_handler;
 	ret = amd_wbrf_register_notifier(&smu->wbrf_notifier);
 	if (ret)
@@ -1464,11 +1480,10 @@ static int smu_wbrf_init(struct smu_context *smu)
 	 * before our driver loaded. To make sure our driver
 	 * is awared of those exclusion ranges.
 	 */
-	ret = smu_wbrf_handle_exclusion_ranges(smu);
-	if (ret)
-		dev_err(adev->dev, "Failed to handle wbrf exclusion ranges\n");
+	schedule_delayed_work(&smu->wbrf_delayed_work,
+			      msecs_to_jiffies(SMU_WBRF_EVENT_HANDLING_PACE));
 
-	return ret;
+	return 0;
 }
 
 /**
@@ -1484,6 +1499,8 @@ static void smu_wbrf_fini(struct smu_context *smu)
 		return;
 
 	amd_wbrf_unregister_notifier(&smu->wbrf_notifier);
+
+	cancel_delayed_work_sync(&smu->wbrf_delayed_work);
 }
 
 static int smu_smc_hw_setup(struct smu_context *smu)

drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h

@@ -473,6 +473,12 @@ struct stb_context {
 
 #define WORKLOAD_POLICY_MAX 7
 
+/*
+ * Configure wbrf event handling pace as there can be only one
+ * event processed every SMU_WBRF_EVENT_HANDLING_PACE ms.
+ */
+#define SMU_WBRF_EVENT_HANDLING_PACE	10
+
 struct smu_context {
 	struct amdgpu_device            *adev;
 	struct amdgpu_irq_src		irq_source;
@@ -576,6 +582,7 @@ struct smu_context {
 	/* data structures for wbrf feature support */
 	bool				wbrf_supported;
 	struct notifier_block		wbrf_notifier;
+	struct delayed_work		wbrf_delayed_work;
 };
 
 struct i2c_adapter;