[v3,6/7] drm/panthor: Add suspend, resume and reset handling

Commit Message

Lukas Zapolskas April 1, 2025, 3:48 p.m. UTC

The sampler must disable and re-enable counter sampling around suspends,
and must re-program the FW interface after a reset to avoid losing
data.

Signed-off-by: Lukas Zapolskas <[e-mail]>
---
 drivers/gpu/drm/panthor/panthor_device.c |   7 +-
 drivers/gpu/drm/panthor/panthor_perf.c   | 102 +++++++++++++++++++++++
 drivers/gpu/drm/panthor/panthor_perf.h   |   6 ++
 3 files changed, 114 insertions(+), 1 deletion(-)

Patch

diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
index 7ac985d44655..92624a8717c5 100644
--- a/drivers/gpu/drm/panthor/panthor_device.c
+++ b/drivers/gpu/drm/panthor/panthor_device.c
@@ -139,6 +139,7 @@  static void panthor_device_reset_work(struct work_struct *work)
 	if (!drm_dev_enter(&ptdev->base, &cookie))
 		return;
 
+	panthor_perf_pre_reset(ptdev);
 	panthor_sched_pre_reset(ptdev);
 	panthor_fw_pre_reset(ptdev, true);
 	panthor_mmu_pre_reset(ptdev);
@@ -148,6 +149,7 @@  static void panthor_device_reset_work(struct work_struct *work)
 	ret = panthor_fw_post_reset(ptdev);
 	atomic_set(&ptdev->reset.pending, 0);
 	panthor_sched_post_reset(ptdev, ret != 0);
+	panthor_perf_post_reset(ptdev);
 	drm_dev_exit(cookie);
 
 	if (ret) {
@@ -496,8 +498,10 @@  int panthor_device_resume(struct device *dev)
 			ret = panthor_device_resume_hw_components(ptdev);
 		}
 
-		if (!ret)
+		if (!ret) {
 			panthor_sched_resume(ptdev);
+			panthor_perf_resume(ptdev);
+		}
 
 		drm_dev_exit(cookie);
 
@@ -561,6 +565,7 @@  int panthor_device_suspend(struct device *dev)
 		/* We prepare everything as if we were resetting the GPU.
 		 * The end of the reset will happen in the resume path though.
 		 */
+		panthor_perf_suspend(ptdev);
 		panthor_sched_suspend(ptdev);
 		panthor_fw_suspend(ptdev);
 		panthor_mmu_suspend(ptdev);
diff --git a/drivers/gpu/drm/panthor/panthor_perf.c b/drivers/gpu/drm/panthor/panthor_perf.c
index 3cb79b999886..753c65294745 100644
--- a/drivers/gpu/drm/panthor/panthor_perf.c
+++ b/drivers/gpu/drm/panthor/panthor_perf.c
@@ -1803,6 +1803,76 @@  void panthor_perf_session_destroy(struct panthor_file *pfile, struct panthor_per
 	}
 }
 
+static int panthor_perf_sampler_resume(struct panthor_perf_sampler *sampler)
+{
+	int ret;
+
+	if (!atomic_read(&sampler->enabled_clients))
+		return 0;
+
+	ret = panthor_perf_fw_start_sampling(sampler->ptdev);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int panthor_perf_sampler_suspend(struct panthor_perf_sampler *sampler)
+{
+	int ret;
+
+	if (!atomic_read(&sampler->enabled_clients))
+		return 0;
+
+	ret = panthor_perf_fw_stop_sampling(sampler->ptdev);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+/**
+ * panthor_perf_suspend - Prepare the performance counter subsystem for system suspend.
+ * @ptdev: Panthor device.
+ *
+ * Indicate to the performance counters that the system is suspending.
+ *
+ * This function must not be used to handle MCU power state transitions: just before MCU goes
+ * from on to any inactive state, an automatic sample will be performed by the firmware, and
+ * the performance counter firmware state will be restored on warm boot.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int panthor_perf_suspend(struct panthor_device *ptdev)
+{
+	struct panthor_perf *perf = ptdev->perf;
+
+	if (!perf)
+		return 0;
+
+	return panthor_perf_sampler_suspend(&perf->sampler);
+}
+
+/**
+ * panthor_perf_resume - Resume the performance counter subsystem after system resumption.
+ * @ptdev: Panthor device.
+ *
+ * Indicate to the performance counters that the system has resumed. This must not be used
+ * to handle MCU state transitions, for the same reasons as detailed in the kerneldoc for
+ * @panthor_perf_suspend.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int panthor_perf_resume(struct panthor_device *ptdev)
+{
+	struct panthor_perf *perf = ptdev->perf;
+
+	if (!perf)
+		return 0;
+
+	return panthor_perf_sampler_resume(&perf->sampler);
+}
+
 /**
  * panthor_perf_unplug - Terminate the performance counter subsystem.
  * @ptdev: Panthor device.
@@ -1836,3 +1906,35 @@  void panthor_perf_unplug(struct panthor_device *ptdev)
 
 	ptdev->perf = NULL;
 }
+
+void panthor_perf_pre_reset(struct panthor_device *ptdev)
+{
+	struct panthor_perf_sampler *sampler;
+
+	if (!ptdev || !ptdev->perf)
+		return;
+
+	sampler = &ptdev->perf->sampler;
+
+	if (!atomic_read(&sampler->enabled_clients))
+		return;
+
+	panthor_perf_fw_stop_sampling(sampler->ptdev);
+}
+
+void panthor_perf_post_reset(struct panthor_device *ptdev)
+{
+	struct panthor_perf_sampler *sampler;
+
+	if (!ptdev || !ptdev->perf)
+		return;
+
+	sampler = &ptdev->perf->sampler;
+
+	if (!atomic_read(&sampler->enabled_clients))
+		return;
+
+	panthor_perf_fw_write_sampler_config(sampler);
+
+	panthor_perf_fw_start_sampling(sampler->ptdev);
+}
diff --git a/drivers/gpu/drm/panthor/panthor_perf.h b/drivers/gpu/drm/panthor/panthor_perf.h
index c482198b6fbd..fc08a5440a35 100644
--- a/drivers/gpu/drm/panthor/panthor_perf.h
+++ b/drivers/gpu/drm/panthor/panthor_perf.h
@@ -13,6 +13,8 @@  struct panthor_file;
 struct panthor_perf;
 
 int panthor_perf_init(struct panthor_device *ptdev);
+int panthor_perf_suspend(struct panthor_device *ptdev);
+int panthor_perf_resume(struct panthor_device *ptdev);
 void panthor_perf_unplug(struct panthor_device *ptdev);
 
 int panthor_perf_session_setup(struct panthor_device *ptdev, struct panthor_perf *perf,
@@ -30,5 +32,9 @@  void panthor_perf_session_destroy(struct panthor_file *pfile, struct panthor_per
 
 void panthor_perf_report_irq(struct panthor_device *ptdev, u32 status);
 
+void panthor_perf_pre_reset(struct panthor_device *ptdev);
+
+void panthor_perf_post_reset(struct panthor_device *ptdev);
+
 #endif /* __PANTHOR_PERF_H__ */