[PATCH 7/9] drm/amd/pm: add flood detection for wbrf events

[Evan Quan]

To protect PMFW from being overloaded.

Signed-off-by: Evan Quan <evan.quan at amd.com>
--
v1->v2:
  - utilize the delayed work(Lijo, Christian)
  - split the new module parameter changes out(Christian, Alex)
v2->v3:
  - simplify the flood detection further per latest design
v3->v4:
  - drop unneeded wbrf_mutex(Lijo, Christian)
  - use schedule_delayed_work() to avoid possible concurrent
    access(Chrisitan)
---
 drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c     | 28 ++++++++++++++++---
 drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h |  7 +++++
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c b/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c
index 89f876cc60e6..2619e310ef54 100644
--- a/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c
+++ b/drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c
@@ -1272,6 +1272,22 @@ static void smu_wbrf_event_handler(struct amdgpu_device *adev)
 {
 	struct smu_context *smu = adev->powerplay.pp_handle;
 
+	schedule_delayed_work(&smu->wbrf_delayed_work,
+			      msecs_to_jiffies(SMU_WBRF_EVENT_HANDLING_PACE));
+}
+
+/**
+ * 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);
 }
 
@@ -1311,6 +1327,9 @@ static int smu_wbrf_init(struct smu_context *smu)
 	if (!smu->wbrf_supported)
 		return 0;
 
+	INIT_DELAYED_WORK(&smu->wbrf_delayed_work,
+			  smu_wbrf_delayed_work_handler);
+
 	ret = amdgpu_acpi_register_wbrf_notify_handler(adev,
 						       smu_wbrf_event_handler);
 	if (ret)
@@ -1321,11 +1340,10 @@ 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;
 }
 
 /**
@@ -1343,6 +1361,8 @@ static void smu_wbrf_fini(struct smu_context *smu)
 		return;
 
 	amdgpu_acpi_unregister_wbrf_notify_handler(adev);
+
+	cancel_delayed_work_sync(&smu->wbrf_delayed_work);
 }
 
 static int smu_smc_hw_setup(struct smu_context *smu)
diff --git a/drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h b/drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h
index ff0af3da0be2..aa63cc43d41c 100644
--- a/drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h
+++ b/drivers/gpu/drm/amd/pm/swsmu/inc/amdgpu_smu.h
@@ -478,6 +478,12 @@ 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;
@@ -576,6 +582,7 @@ struct smu_context
 
 	/* data structures for wbrf feature support */
 	bool				wbrf_supported;
+	struct delayed_work		wbrf_delayed_work;
 };
 
 struct i2c_adapter;
-- 
2.34.1