[v3,3/7] drm/panthor: Add panthor perf initialization and termination

Commit Message

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

Added the panthor_perf system initialization and unplug code to allow
for the handling of userspace sessions to be added in follow-up
patches.

Signed-off-by: Lukas Zapolskas <[e-mail]>
---
 drivers/gpu/drm/panthor/panthor_device.c |  2 +
 drivers/gpu/drm/panthor/panthor_device.h |  5 +-
 drivers/gpu/drm/panthor/panthor_perf.c   | 62 +++++++++++++++++++++++-
 drivers/gpu/drm/panthor/panthor_perf.h   |  1 +
 4 files changed, 68 insertions(+), 2 deletions(-)

Patch

diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
index 76b4cf3dc391..7ac985d44655 100644
--- a/drivers/gpu/drm/panthor/panthor_device.c
+++ b/drivers/gpu/drm/panthor/panthor_device.c
@@ -98,6 +98,7 @@  void panthor_device_unplug(struct panthor_device *ptdev)
 	/* Now, try to cleanly shutdown the GPU before the device resources
 	 * get reclaimed.
 	 */
+	panthor_perf_unplug(ptdev);
 	panthor_sched_unplug(ptdev);
 	panthor_fw_unplug(ptdev);
 	panthor_mmu_unplug(ptdev);
@@ -277,6 +278,7 @@  int panthor_device_init(struct panthor_device *ptdev)
 
 err_disable_autosuspend:
 	pm_runtime_dont_use_autosuspend(ptdev->base.dev);
+	panthor_perf_unplug(ptdev);
 	panthor_sched_unplug(ptdev);
 
 err_unplug_fw:
diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h
index 657ccc39568c..818c4d96d448 100644
--- a/drivers/gpu/drm/panthor/panthor_device.h
+++ b/drivers/gpu/drm/panthor/panthor_device.h
@@ -27,7 +27,7 @@  struct panthor_heap_pool;
 struct panthor_job;
 struct panthor_mmu;
 struct panthor_fw;
-struct panthor_perfcnt;
+struct panthor_perf;
 struct panthor_vm;
 struct panthor_vm_pool;
 
@@ -138,6 +138,9 @@  struct panthor_device {
 	/** @devfreq: Device frequency scaling management data. */
 	struct panthor_devfreq *devfreq;
 
+	/** @perf: Performance counter management data. */
+	struct panthor_perf *perf;
+
 	/** @unplug: Device unplug related fields. */
 	struct {
 		/** @lock: Lock used to serialize unplug operations. */
diff --git a/drivers/gpu/drm/panthor/panthor_perf.c b/drivers/gpu/drm/panthor/panthor_perf.c
index b0a6f3fca8a9..7c59c8642b7c 100644
--- a/drivers/gpu/drm/panthor/panthor_perf.c
+++ b/drivers/gpu/drm/panthor/panthor_perf.c
@@ -9,6 +9,19 @@ 
 #include "panthor_fw.h"
 #include "panthor_perf.h"
 
+struct panthor_perf {
+	/** @next_session: The ID of the next session. */
+	u32 next_session;
+
+	/** @session_range: The number of sessions supported at a time. */
+	struct xa_limit session_range;
+
+	/**
+	 * @sessions: Global map of sessions, accessed by their ID.
+	 */
+	struct xarray sessions;
+};
+
 /**
  * PANTHOR_PERF_COUNTERS_PER_BLOCK - On CSF architectures pre-11.x, the number of counters
  * per block was hardcoded to be 64. Arch 11.0 onwards supports the PRFCNT_FEATURES GPU register,
@@ -42,14 +55,61 @@  static void panthor_perf_info_init(struct panthor_device *ptdev)
  * panthor_perf_init - Initialize the performance counter subsystem.
  * @ptdev: Panthor device
  *
+ * The performance counters require the FW interface to be available to setup the
+ * sampling ringbuffers, so this must be called only after FW is initialized.
+ *
  * Return: 0 on success, negative error code on failure.
  */
 int panthor_perf_init(struct panthor_device *ptdev)
 {
+	struct panthor_perf *perf __free(kfree) = NULL;
+	int ret = 0;
+
 	if (!ptdev)
 		return -EINVAL;
 
 	panthor_perf_info_init(ptdev);
 
-	return 0;
+	perf = kzalloc(sizeof(*perf), GFP_KERNEL);
+	if (ZERO_OR_NULL_PTR(perf))
+		return -ENOMEM;
+
+	xa_init_flags(&perf->sessions, XA_FLAGS_ALLOC);
+
+	perf->session_range = (struct xa_limit) {
+		.min = 0,
+		.max = 1,
+	};
+
+	drm_info(&ptdev->base, "Performance counter subsystem initialized");
+
+	ptdev->perf = no_free_ptr(perf);
+
+	return ret;
+}
+
+/**
+ * panthor_perf_unplug - Terminate the performance counter subsystem.
+ * @ptdev: Panthor device.
+ *
+ * This function will terminate the performance counter control structures and any remaining
+ * sessions, after waiting for any pending interrupts.
+ */
+void panthor_perf_unplug(struct panthor_device *ptdev)
+{
+	struct panthor_perf *perf = ptdev->perf;
+
+	if (!perf)
+		return;
+
+	if (!xa_empty(&perf->sessions)) {
+		drm_err(&ptdev->base,
+			"Performance counter sessions active when unplugging the driver!");
+	}
+
+	xa_destroy(&perf->sessions);
+
+	kfree(ptdev->perf);
+
+	ptdev->perf = NULL;
 }
diff --git a/drivers/gpu/drm/panthor/panthor_perf.h b/drivers/gpu/drm/panthor/panthor_perf.h
index 3c32c24c164c..e4805727b9e7 100644
--- a/drivers/gpu/drm/panthor/panthor_perf.h
+++ b/drivers/gpu/drm/panthor/panthor_perf.h
@@ -10,6 +10,7 @@ 
 struct panthor_device;
 
 int panthor_perf_init(struct panthor_device *ptdev);
+void panthor_perf_unplug(struct panthor_device *ptdev);
 
 #endif /* __PANTHOR_PERF_H__ */