Commit b12f3ea7 authored by Adrián Larumbe's avatar Adrián Larumbe Committed by Boris Brezillon
Browse files

drm/panfrost: Replace fdinfo's profiling debugfs knob with sysfs 



Debugfs isn't always available in production builds that try to squeeze
every single byte out of the kernel image, but we still need a way to
toggle the timestamp and cycle counter registers so that jobs can be
profiled for fdinfo's drm engine and cycle calculations.

Drop the debugfs knob and replace it with a sysfs file that accomplishes
the same functionality, and document its ABI in a separate file.

Signed-off-by: default avatarAdrián Larumbe <adrian.larumbe@collabora.com>
Reviewed-by: default avatarBoris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: default avatarSteven Price <steven.price@arm.com>
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240306015819.822128-2-adrian.larumbe@collabora.com
parent 57a4e3a9

Documentation/ABI/testing/sysfs-driver-panfrost-profiling

0 → 100644
+10 −0
Original line number Diff line number Diff line 
What:		/sys/bus/platform/drivers/panfrost/.../profiling

Date:		February 2024

KernelVersion:	6.8.0

Contact:	Adrian Larumbe <adrian.larumbe@collabora.com>

Description:

		Get/set drm fdinfo's engine and cycles profiling status.

		Valid values are:

		0: Don't enable fdinfo job profiling sources.

		1: Enable fdinfo job profiling sources, this enables both the GPU's

		   timestamp and cycle counter registers.
 
 No newline at end of file

Documentation/gpu/panfrost.rst

+9 −0
Original line number Diff line number Diff line
@@ -38,3 +38,12 @@ the currently possible format options: 


Possible `drm-engine-` key names are: `fragment`, and  `vertex-tiler`.

`drm-curfreq-` values convey the current operating frequency for that engine.



Users must bear in mind that engine and cycle sampling are disabled by default,

because of power saving concerns. `fdinfo` users and benchmark applications which

query the fdinfo file must make sure to toggle the job profiling status of the

driver by writing into the appropriate sysfs node::



    echo <N> > /sys/bus/platform/drivers/panfrost/[a-f0-9]*.gpu/profiling



Where `N` is either `0` or `1`, depending on the desired enablement status.

drivers/gpu/drm/panfrost/Makefile

+0 −2
Original line number Diff line number Diff line
@@ -12,6 +12,4 @@ panfrost-y := \ 
	panfrost_perfcnt.o \

	panfrost_dump.o



panfrost-$(CONFIG_DEBUG_FS) += panfrost_debugfs.o



obj-$(CONFIG_DRM_PANFROST) += panfrost.o

drivers/gpu/drm/panfrost/panfrost_debugfs.c

deleted100644 → 0
+0 −21
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/* Copyright 2023 Collabora ltd. */

/* Copyright 2023 Amazon.com, Inc. or its affiliates. */



#include <linux/debugfs.h>

#include <linux/platform_device.h>

#include <drm/drm_debugfs.h>

#include <drm/drm_file.h>

#include <drm/panfrost_drm.h>



#include "panfrost_device.h"

#include "panfrost_gpu.h"

#include "panfrost_debugfs.h"



void panfrost_debugfs_init(struct drm_minor *minor)

{

	struct drm_device *dev = minor->dev;

	struct panfrost_device *pfdev = platform_get_drvdata(to_platform_device(dev->dev));



	debugfs_create_atomic_t("profile", 0600, minor->debugfs_root, &pfdev->profile_mode);

}

drivers/gpu/drm/panfrost/panfrost_debugfs.h

deleted100644 → 0
+0 −14
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

/*

 * Copyright 2023 Collabora ltd.

 * Copyright 2023 Amazon.com, Inc. or its affiliates.

 */



#ifndef PANFROST_DEBUGFS_H

#define PANFROST_DEBUGFS_H



#ifdef CONFIG_DEBUG_FS

void panfrost_debugfs_init(struct drm_minor *minor);

#endif



#endif  /* PANFROST_DEBUGFS_H */