This change adds the IOCTL to query data about the performance counter
setup. Some of this data was available via previous DEV_QUERY calls,
for instance for GPU info, but exposing it via PERF_INFO
minimizes the overhead of creating a single session to just the one
aggregate IOCTL.

Signed-off-by: Lukas Zapolskas <lukas.zapolskas@arm.com>
Reviewed-by: Adrián Larumbe <adrian.larumbe@collabora.com>
---
 drivers/gpu/drm/panthor/Makefile         |  1 +
 drivers/gpu/drm/panthor/panthor_device.c |  7 +++
 drivers/gpu/drm/panthor/panthor_device.h |  3 +
 drivers/gpu/drm/panthor/panthor_drv.c    | 10 ++-
 drivers/gpu/drm/panthor/panthor_fw.h     |  3 +
 drivers/gpu/drm/panthor/panthor_perf.c   | 77 ++++++++++++++++++++++++
 drivers/gpu/drm/panthor/panthor_perf.h   | 15 +++++
 drivers/gpu/drm/panthor/panthor_regs.h   |  1 +
 8 files changed, 116 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpu/drm/panthor/panthor_perf.c
 create mode 100644 drivers/gpu/drm/panthor/panthor_perf.h

diff --git a/drivers/gpu/drm/panthor/Makefile b/drivers/gpu/drm/panthor/Makefile
index 15294719b09c..0df9947f3575 100644
--- a/drivers/gpu/drm/panthor/Makefile
+++ b/drivers/gpu/drm/panthor/Makefile
@@ -9,6 +9,7 @@ panthor-y := \
 	panthor_gpu.o \
 	panthor_heap.o \
 	panthor_mmu.o \
+	panthor_perf.o \
 	panthor_sched.o
 
 obj-$(CONFIG_DRM_PANTHOR) += panthor.o
diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
index f0b2da5b2b96..15ab329722cc 100644
--- a/drivers/gpu/drm/panthor/panthor_device.c
+++ b/drivers/gpu/drm/panthor/panthor_device.c
@@ -19,6 +19,7 @@
 #include "panthor_fw.h"
 #include "panthor_gpu.h"
 #include "panthor_mmu.h"
+#include "panthor_perf.h"
 #include "panthor_regs.h"
 #include "panthor_sched.h"
 
@@ -264,6 +265,10 @@ int panthor_device_init(struct panthor_device *ptdev)
 	if (ret)
 		goto err_unplug_fw;
 
+	ret = panthor_perf_init(ptdev);
+	if (ret)
+		goto err_unplug_sched;
+
 	/* ~3 frames */
 	pm_runtime_set_autosuspend_delay(ptdev->base.dev, 50);
 	pm_runtime_use_autosuspend(ptdev->base.dev);
@@ -277,6 +282,8 @@ int panthor_device_init(struct panthor_device *ptdev)
 
 err_disable_autosuspend:
 	pm_runtime_dont_use_autosuspend(ptdev->base.dev);
+
+err_unplug_sched:
 	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 4fc7cf2aeed5..720d39b9e783 100644
--- a/drivers/gpu/drm/panthor/panthor_device.h
+++ b/drivers/gpu/drm/panthor/panthor_device.h
@@ -120,6 +120,9 @@ struct panthor_device {
 	/** @csif_info: Command stream interface information. */
 	struct drm_panthor_csif_info csif_info;
 
+	/** @perf_info: Performance counter interface information. */
+	struct drm_panthor_perf_info perf_info;
+
 	/** @gpu: GPU management data. */
 	struct panthor_gpu *gpu;
 
diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
index 9256806eb662..8b1e3e38b12e 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/drivers/gpu/drm/panthor/panthor_drv.c
@@ -175,7 +175,8 @@ panthor_get_uobj_array(const struct drm_panthor_obj_array *in, u32 min_stride,
 		 PANTHOR_UOBJ_DECL(struct drm_panthor_sync_op, timeline_value), \
 		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_submit, syncs), \
 		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_create, ringbuf_size), \
-		 PANTHOR_UOBJ_DECL(struct drm_panthor_vm_bind_op, syncs))
+		 PANTHOR_UOBJ_DECL(struct drm_panthor_vm_bind_op, syncs), \
+		 PANTHOR_UOBJ_DECL(struct drm_panthor_perf_info, shader_blocks))
 
 /**
  * PANTHOR_UOBJ_SET() - Copy a kernel object to a user object.
@@ -835,6 +836,10 @@ static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct d
 			args->size = sizeof(priorities_info);
 			return 0;
 
+		case DRM_PANTHOR_DEV_QUERY_PERF_INFO:
+			args->size = sizeof(ptdev->perf_info);
+			return 0;
+
 		default:
 			return -EINVAL;
 		}
@@ -859,6 +864,9 @@ static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct d
 		panthor_query_group_priorities_info(file, &priorities_info);
 		return PANTHOR_UOBJ_SET(args->pointer, args->size, priorities_info);
 
+	case DRM_PANTHOR_DEV_QUERY_PERF_INFO:
+		return PANTHOR_UOBJ_SET(args->pointer, args->size, ptdev->perf_info);
+
 	default:
 		return -EINVAL;
 	}
diff --git a/drivers/gpu/drm/panthor/panthor_fw.h b/drivers/gpu/drm/panthor/panthor_fw.h
index 6598d96c6d2a..8bcb933fa790 100644
--- a/drivers/gpu/drm/panthor/panthor_fw.h
+++ b/drivers/gpu/drm/panthor/panthor_fw.h
@@ -197,8 +197,11 @@ struct panthor_fw_global_control_iface {
 	u32 output_va;
 	u32 group_num;
 	u32 group_stride;
+#define GLB_PERFCNT_FW_SIZE(x) ((((x) >> 16) << 8))
 	u32 perfcnt_size;
 	u32 instr_features;
+#define PERFCNT_FEATURES_MD_SIZE(x) (((x) & GENMASK(3, 0)) << 8)
+	u32 perfcnt_features;
 };
 
 struct panthor_fw_global_input_iface {
diff --git a/drivers/gpu/drm/panthor/panthor_perf.c b/drivers/gpu/drm/panthor/panthor_perf.c
new file mode 100644
index 000000000000..e58a62ad7988
--- /dev/null
+++ b/drivers/gpu/drm/panthor/panthor_perf.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0 or MIT
+/* Copyright 2023 Collabora Ltd */
+/* Copyright 2025 Arm ltd. */
+
+#include <linux/bitops.h>
+#include <drm/panthor_drm.h>
+
+#include "panthor_device.h"
+#include "panthor_fw.h"
+#include "panthor_perf.h"
+#include "panthor_regs.h"
+
+struct panthor_perf_counter_block {
+	struct drm_panthor_perf_block_header header;
+	u64 counters[];
+};
+
+static size_t get_annotated_block_size(size_t counters_per_block)
+{
+	return struct_size_t(struct panthor_perf_counter_block, counters, counters_per_block);
+}
+
+static size_t session_get_user_sample_size(const struct drm_panthor_perf_info *const info)
+{
+	const size_t block_size = get_annotated_block_size(info->counters_per_block);
+	const size_t block_nr = info->cshw_blocks + info->fw_blocks +
+		info->tiler_blocks + info->memsys_blocks + info->shader_blocks;
+
+	return info->sample_header_size + (block_size * block_nr);
+}
+
+/**
+ * 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,
+ * which indicates the same information.
+ */
+#define PANTHOR_PERF_COUNTERS_PER_BLOCK (64)
+
+static void panthor_perf_info_init(struct panthor_device *const ptdev)
+{
+	struct panthor_fw_global_iface *glb_iface = panthor_fw_get_glb_iface(ptdev);
+	struct drm_panthor_perf_info *const perf_info = &ptdev->perf_info;
+
+	if (PERFCNT_FEATURES_MD_SIZE(glb_iface->control->perfcnt_features))
+		perf_info->flags |= DRM_PANTHOR_PERF_BLOCK_STATES_SUPPORT;
+
+	perf_info->counters_per_block = PANTHOR_PERF_COUNTERS_PER_BLOCK;
+
+	perf_info->sample_header_size = sizeof(struct drm_panthor_perf_sample_header);
+	perf_info->block_header_size = sizeof(struct drm_panthor_perf_block_header);
+
+	if (GLB_PERFCNT_FW_SIZE(glb_iface->control->perfcnt_size))
+		perf_info->fw_blocks = 1;
+
+	perf_info->cshw_blocks = 1;
+	perf_info->tiler_blocks = 1;
+	perf_info->memsys_blocks = GPU_MEM_FEATURES_L2_SLICES(ptdev->gpu_info.mem_features);
+	perf_info->shader_blocks = hweight64(ptdev->gpu_info.shader_present);
+
+	perf_info->sample_size = session_get_user_sample_size(perf_info);
+}
+
+/**
+ * panthor_perf_init - Initialize the performance counter subsystem.
+ * @ptdev: Panthor device
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int panthor_perf_init(struct panthor_device *ptdev)
+{
+	if (!ptdev)
+		return -EINVAL;
+
+	panthor_perf_info_init(ptdev);
+
+	return 0;
+}
diff --git a/drivers/gpu/drm/panthor/panthor_perf.h b/drivers/gpu/drm/panthor/panthor_perf.h
new file mode 100644
index 000000000000..3c32c24c164c
--- /dev/null
+++ b/drivers/gpu/drm/panthor/panthor_perf.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 or MIT */
+/* Copyright 2025 Collabora Ltd */
+/* Copyright 2025 Arm ltd. */
+
+#ifndef __PANTHOR_PERF_H__
+#define __PANTHOR_PERF_H__
+
+#include <linux/types.h>
+
+struct panthor_device;
+
+int panthor_perf_init(struct panthor_device *ptdev);
+
+#endif /* __PANTHOR_PERF_H__ */
+
diff --git a/drivers/gpu/drm/panthor/panthor_regs.h b/drivers/gpu/drm/panthor/panthor_regs.h
index 48bbfd40138c..d613ce723981 100644
--- a/drivers/gpu/drm/panthor/panthor_regs.h
+++ b/drivers/gpu/drm/panthor/panthor_regs.h
@@ -27,6 +27,7 @@
 #define GPU_TILER_FEATURES				0xC
 #define GPU_MEM_FEATURES				0x10
 #define   GROUPS_L2_COHERENT				BIT(0)
+#define   GPU_MEM_FEATURES_L2_SLICES(x)			((((x) & GENMASK(11, 8)) >> 8) + 1)
 
 #define GPU_MMU_FEATURES				0x14
 #define  GPU_MMU_FEATURES_VA_BITS(x)			((x) & GENMASK(7, 0))
-- 
2.33.0.dirty

Hi Lukas,

On 25.07.2025 15:57, Lukas Zapolskas wrote:
> This change adds the IOCTL to query data about the performance counter
> setup. Some of this data was available via previous DEV_QUERY calls,
> for instance for GPU info, but exposing it via PERF_INFO
> minimizes the overhead of creating a single session to just the one
> aggregate IOCTL.
>
> Signed-off-by: Lukas Zapolskas <lukas.zapolskas@arm.com>
> Reviewed-by: Adrián Larumbe <adrian.larumbe@collabora.com>
> ---
>  drivers/gpu/drm/panthor/Makefile         |  1 +
>  drivers/gpu/drm/panthor/panthor_device.c |  7 +++
>  drivers/gpu/drm/panthor/panthor_device.h |  3 +
>  drivers/gpu/drm/panthor/panthor_drv.c    | 10 ++-
>  drivers/gpu/drm/panthor/panthor_fw.h     |  3 +
>  drivers/gpu/drm/panthor/panthor_perf.c   | 77 ++++++++++++++++++++++++
>  drivers/gpu/drm/panthor/panthor_perf.h   | 15 +++++
>  drivers/gpu/drm/panthor/panthor_regs.h   |  1 +
>  8 files changed, 116 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/gpu/drm/panthor/panthor_perf.c
>  create mode 100644 drivers/gpu/drm/panthor/panthor_perf.h
>
> diff --git a/drivers/gpu/drm/panthor/Makefile b/drivers/gpu/drm/panthor/Makefile
> index 15294719b09c..0df9947f3575 100644
> --- a/drivers/gpu/drm/panthor/Makefile
> +++ b/drivers/gpu/drm/panthor/Makefile
> @@ -9,6 +9,7 @@ panthor-y := \
>  	panthor_gpu.o \
>  	panthor_heap.o \
>  	panthor_mmu.o \
> +	panthor_perf.o \
>  	panthor_sched.o
>
>  obj-$(CONFIG_DRM_PANTHOR) += panthor.o
> diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
> index f0b2da5b2b96..15ab329722cc 100644
> --- a/drivers/gpu/drm/panthor/panthor_device.c
> +++ b/drivers/gpu/drm/panthor/panthor_device.c
> @@ -19,6 +19,7 @@
>  #include "panthor_fw.h"
>  #include "panthor_gpu.h"
>  #include "panthor_mmu.h"
> +#include "panthor_perf.h"
>  #include "panthor_regs.h"
>  #include "panthor_sched.h"
>
> @@ -264,6 +265,10 @@ int panthor_device_init(struct panthor_device *ptdev)
>  	if (ret)
>  		goto err_unplug_fw;
>
> +	ret = panthor_perf_init(ptdev);
> +	if (ret)
> +		goto err_unplug_sched;
> +
>  	/* ~3 frames */
>  	pm_runtime_set_autosuspend_delay(ptdev->base.dev, 50);
>  	pm_runtime_use_autosuspend(ptdev->base.dev);
> @@ -277,6 +282,8 @@ int panthor_device_init(struct panthor_device *ptdev)
>
>  err_disable_autosuspend:
>  	pm_runtime_dont_use_autosuspend(ptdev->base.dev);
> +
> +err_unplug_sched:
>  	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 4fc7cf2aeed5..720d39b9e783 100644
> --- a/drivers/gpu/drm/panthor/panthor_device.h
> +++ b/drivers/gpu/drm/panthor/panthor_device.h
> @@ -120,6 +120,9 @@ struct panthor_device {
>  	/** @csif_info: Command stream interface information. */
>  	struct drm_panthor_csif_info csif_info;
>
> +	/** @perf_info: Performance counter interface information. */
> +	struct drm_panthor_perf_info perf_info;
> +
>  	/** @gpu: GPU management data. */
>  	struct panthor_gpu *gpu;
>
> diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
> index 9256806eb662..8b1e3e38b12e 100644
> --- a/drivers/gpu/drm/panthor/panthor_drv.c
> +++ b/drivers/gpu/drm/panthor/panthor_drv.c
> @@ -175,7 +175,8 @@ panthor_get_uobj_array(const struct drm_panthor_obj_array *in, u32 min_stride,
>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_sync_op, timeline_value), \
>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_submit, syncs), \
>  		 PANTHOR_UOBJ_DECL(struct drm_panthor_queue_create, ringbuf_size), \
> -		 PANTHOR_UOBJ_DECL(struct drm_panthor_vm_bind_op, syncs))
> +		 PANTHOR_UOBJ_DECL(struct drm_panthor_vm_bind_op, syncs), \
> +		 PANTHOR_UOBJ_DECL(struct drm_panthor_perf_info, shader_blocks))
>
>  /**
>   * PANTHOR_UOBJ_SET() - Copy a kernel object to a user object.
> @@ -835,6 +836,10 @@ static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct d
>  			args->size = sizeof(priorities_info);
>  			return 0;
>
> +		case DRM_PANTHOR_DEV_QUERY_PERF_INFO:
> +			args->size = sizeof(ptdev->perf_info);
> +			return 0;
> +
>  		default:
>  			return -EINVAL;
>  		}
> @@ -859,6 +864,9 @@ static int panthor_ioctl_dev_query(struct drm_device *ddev, void *data, struct d
>  		panthor_query_group_priorities_info(file, &priorities_info);
>  		return PANTHOR_UOBJ_SET(args->pointer, args->size, priorities_info);
>
> +	case DRM_PANTHOR_DEV_QUERY_PERF_INFO:
> +		return PANTHOR_UOBJ_SET(args->pointer, args->size, ptdev->perf_info);
> +
>  	default:
>  		return -EINVAL;
>  	}
> diff --git a/drivers/gpu/drm/panthor/panthor_fw.h b/drivers/gpu/drm/panthor/panthor_fw.h
> index 6598d96c6d2a..8bcb933fa790 100644
> --- a/drivers/gpu/drm/panthor/panthor_fw.h
> +++ b/drivers/gpu/drm/panthor/panthor_fw.h
> @@ -197,8 +197,11 @@ struct panthor_fw_global_control_iface {
>  	u32 output_va;
>  	u32 group_num;
>  	u32 group_stride;
> +#define GLB_PERFCNT_FW_SIZE(x) ((((x) >> 16) << 8))
>  	u32 perfcnt_size;
>  	u32 instr_features;
> +#define PERFCNT_FEATURES_MD_SIZE(x) (((x) & GENMASK(3, 0)) << 8)
> +	u32 perfcnt_features;
>  };
>
>  struct panthor_fw_global_input_iface {
> diff --git a/drivers/gpu/drm/panthor/panthor_perf.c b/drivers/gpu/drm/panthor/panthor_perf.c
> new file mode 100644
> index 000000000000..e58a62ad7988
> --- /dev/null
> +++ b/drivers/gpu/drm/panthor/panthor_perf.c
> @@ -0,0 +1,77 @@
> +// SPDX-License-Identifier: GPL-2.0 or MIT
> +/* Copyright 2023 Collabora Ltd */
> +/* Copyright 2025 Arm ltd. */
> +
> +#include <linux/bitops.h>
> +#include <drm/panthor_drm.h>
> +
> +#include "panthor_device.h"
> +#include "panthor_fw.h"
> +#include "panthor_perf.h"
> +#include "panthor_regs.h"
> +
> +struct panthor_perf_counter_block {
> +	struct drm_panthor_perf_block_header header;
> +	u64 counters[];
> +};
> +
> +static size_t get_annotated_block_size(size_t counters_per_block)
> +{
> +	return struct_size_t(struct panthor_perf_counter_block, counters, counters_per_block);
> +}
> +
> +static size_t session_get_user_sample_size(const struct drm_panthor_perf_info *const info)
> +{
> +	const size_t block_size = get_annotated_block_size(info->counters_per_block);
> +	const size_t block_nr = info->cshw_blocks + info->fw_blocks +
> +		info->tiler_blocks + info->memsys_blocks + info->shader_blocks;
> +
> +	return info->sample_header_size + (block_size * block_nr);
> +}
> +
> +/**
> + * 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,
> + * which indicates the same information.
> + */
> +#define PANTHOR_PERF_COUNTERS_PER_BLOCK (64)
> +
> +static void panthor_perf_info_init(struct panthor_device *const ptdev)
> +{
> +	struct panthor_fw_global_iface *glb_iface = panthor_fw_get_glb_iface(ptdev);
> +	struct drm_panthor_perf_info *const perf_info = &ptdev->perf_info;
> +
> +	if (PERFCNT_FEATURES_MD_SIZE(glb_iface->control->perfcnt_features))
> +		perf_info->flags |= DRM_PANTHOR_PERF_BLOCK_STATES_SUPPORT;
> +
> +	perf_info->counters_per_block = PANTHOR_PERF_COUNTERS_PER_BLOCK;

I might've mentioned this in a previous review, but maybe we could add PRFCNT_FEATURES register
access in this commit, and both ways of retrieving the number of counters per block depending
in the CSF firmware version?

Other than that:

Reviewed-by: Adrián Larumbe <adrian.larumbe@collabora.com>

> +
> +	perf_info->sample_header_size = sizeof(struct drm_panthor_perf_sample_header);
> +	perf_info->block_header_size = sizeof(struct drm_panthor_perf_block_header);
> +
> +	if (GLB_PERFCNT_FW_SIZE(glb_iface->control->perfcnt_size))
> +		perf_info->fw_blocks = 1;
> +
> +	perf_info->cshw_blocks = 1;
> +	perf_info->tiler_blocks = 1;
> +	perf_info->memsys_blocks = GPU_MEM_FEATURES_L2_SLICES(ptdev->gpu_info.mem_features);
> +	perf_info->shader_blocks = hweight64(ptdev->gpu_info.shader_present);
> +
> +	perf_info->sample_size = session_get_user_sample_size(perf_info);
> +}
> +
> +/**
> + * panthor_perf_init - Initialize the performance counter subsystem.
> + * @ptdev: Panthor device
> + *
> + * Return: 0 on success, negative error code on failure.
> + */
> +int panthor_perf_init(struct panthor_device *ptdev)
> +{
> +	if (!ptdev)
> +		return -EINVAL;
> +
> +	panthor_perf_info_init(ptdev);
> +
> +	return 0;
> +}
> diff --git a/drivers/gpu/drm/panthor/panthor_perf.h b/drivers/gpu/drm/panthor/panthor_perf.h
> new file mode 100644
> index 000000000000..3c32c24c164c
> --- /dev/null
> +++ b/drivers/gpu/drm/panthor/panthor_perf.h
> @@ -0,0 +1,15 @@
> +/* SPDX-License-Identifier: GPL-2.0 or MIT */
> +/* Copyright 2025 Collabora Ltd */
> +/* Copyright 2025 Arm ltd. */
> +
> +#ifndef __PANTHOR_PERF_H__
> +#define __PANTHOR_PERF_H__
> +
> +#include <linux/types.h>
> +
> +struct panthor_device;
> +
> +int panthor_perf_init(struct panthor_device *ptdev);
> +
> +#endif /* __PANTHOR_PERF_H__ */
> +
> diff --git a/drivers/gpu/drm/panthor/panthor_regs.h b/drivers/gpu/drm/panthor/panthor_regs.h
> index 48bbfd40138c..d613ce723981 100644
> --- a/drivers/gpu/drm/panthor/panthor_regs.h
> +++ b/drivers/gpu/drm/panthor/panthor_regs.h
> @@ -27,6 +27,7 @@
>  #define GPU_TILER_FEATURES				0xC
>  #define GPU_MEM_FEATURES				0x10
>  #define   GROUPS_L2_COHERENT				BIT(0)
> +#define   GPU_MEM_FEATURES_L2_SLICES(x)			((((x) & GENMASK(11, 8)) >> 8) + 1)
>
>  #define GPU_MMU_FEATURES				0x14
>  #define  GPU_MMU_FEATURES_VA_BITS(x)			((x) & GENMASK(7, 0))
> --
> 2.33.0.dirty