This commit introduces a DRM device sysfs attribute that lets UM control
the job accounting status in the device. The knob variable had been brought
in as part of a previous commit, but now we're able to fix it manually.

As sysfs files are part of a driver's uAPI, describe its legitimate input
values and output format in a documentation file.

Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
---
 .../testing/sysfs-driver-panthor-profiling    | 10 ++++
 Documentation/gpu/panthor.rst                 | 46 +++++++++++++++++++
 drivers/gpu/drm/panthor/panthor_drv.c         | 39 ++++++++++++++++
 3 files changed, 95 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-driver-panthor-profiling
 create mode 100644 Documentation/gpu/panthor.rst

diff --git a/Documentation/ABI/testing/sysfs-driver-panthor-profiling b/Documentation/ABI/testing/sysfs-driver-panthor-profiling
new file mode 100644
index 000000000000..af05fccedc15
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-panthor-profiling
@@ -0,0 +1,10 @@
+What:		/sys/bus/platform/drivers/panthor/.../profiling
+Date:		September 2024
+KernelVersion:	6.11.0
+Contact:	Adrian Larumbe <adrian.larumbe@collabora.com>
+Description:
+		Bitmask to enable drm fdinfo's job profiling measurements.
+		Valid values are:
+		0: Don't enable fdinfo job profiling sources.
+		1: Enable GPU cycle measurements for running jobs.
+		2: Enable GPU timestamp sampling for running jobs.
diff --git a/Documentation/gpu/panthor.rst b/Documentation/gpu/panthor.rst
new file mode 100644
index 000000000000..cbf5c4429a2d
--- /dev/null
+++ b/Documentation/gpu/panthor.rst
@@ -0,0 +1,46 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+=========================
+ drm/Panthor CSF driver
+=========================
+
+.. _panfrost-usage-stats:
+
+Panthor DRM client usage stats implementation
+==============================================
+
+The drm/Panthor driver implements the DRM client usage stats specification as
+documented in :ref:`drm-client-usage-stats`.
+
+Example of the output showing the implemented key value pairs and entirety of
+the currently possible format options:
+
+::
+     pos:    0
+     flags:  02400002
+     mnt_id: 29
+     ino:    491
+     drm-driver:     panthor
+     drm-client-id:  10
+     drm-engine-panthor:     111110952750 ns
+     drm-cycles-panthor:     94439687187
+     drm-maxfreq-panthor:    1000000000 Hz
+     drm-curfreq-panthor:    1000000000 Hz
+     drm-total-memory:       16480 KiB
+     drm-shared-memory:      0
+     drm-active-memory:      16200 KiB
+     drm-resident-memory:    16480 KiB
+     drm-purgeable-memory:   0
+
+Possible `drm-engine-` key names are: `panthor`.
+`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/panthor/[a-f0-9]*.gpu/profiling
+
+Where `N` is a bit mask where cycle and timestamp sampling are respectively
+enabled by the first and second bits.
diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
index 233b265c0819..6f47d9d1d86a 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/drivers/gpu/drm/panthor/panthor_drv.c
@@ -1513,6 +1513,44 @@ static void panthor_remove(struct platform_device *pdev)
 	panthor_device_unplug(ptdev);
 }
 
+static ssize_t profiling_show(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	struct panthor_device *ptdev = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%d\n", ptdev->profile_mask);
+}
+
+static ssize_t profiling_store(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t len)
+{
+	struct panthor_device *ptdev = dev_get_drvdata(dev);
+	u32 value;
+	int err;
+
+	err = kstrtou32(buf, 0, &value);
+	if (err)
+		return err;
+
+	if ((value & ~PANTHOR_DEVICE_PROFILING_ALL) != 0)
+		return -EINVAL;
+
+	ptdev->profile_mask = value;
+
+	return len;
+}
+
+static DEVICE_ATTR_RW(profiling);
+
+static struct attribute *panthor_attrs[] = {
+	&dev_attr_profiling.attr,
+	NULL,
+};
+
+ATTRIBUTE_GROUPS(panthor);
+
 static const struct of_device_id dt_match[] = {
 	{ .compatible = "rockchip,rk3588-mali" },
 	{ .compatible = "arm,mali-valhall-csf" },
@@ -1532,6 +1570,7 @@ static struct platform_driver panthor_driver = {
 		.name = "panthor",
 		.pm = pm_ptr(&panthor_pm_ops),
 		.of_match_table = dt_match,
+		.dev_groups = panthor_groups,
 	},
 };
 
-- 
2.46.0

On Fri, 13 Sep 2024 13:42:13 +0100
Adrián Larumbe <adrian.larumbe@collabora.com> wrote:

> This commit introduces a DRM device sysfs attribute that lets UM control
> the job accounting status in the device. The knob variable had been brought
> in as part of a previous commit, but now we're able to fix it manually.
> 
> As sysfs files are part of a driver's uAPI, describe its legitimate input
> values and output format in a documentation file.
> 
> Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
> Reviewed-by: Steven Price <steven.price@arm.com>

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

> ---
>  .../testing/sysfs-driver-panthor-profiling    | 10 ++++
>  Documentation/gpu/panthor.rst                 | 46 +++++++++++++++++++
>  drivers/gpu/drm/panthor/panthor_drv.c         | 39 ++++++++++++++++
>  3 files changed, 95 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-driver-panthor-profiling
>  create mode 100644 Documentation/gpu/panthor.rst
> 
> diff --git a/Documentation/ABI/testing/sysfs-driver-panthor-profiling b/Documentation/ABI/testing/sysfs-driver-panthor-profiling
> new file mode 100644
> index 000000000000..af05fccedc15
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-driver-panthor-profiling
> @@ -0,0 +1,10 @@
> +What:		/sys/bus/platform/drivers/panthor/.../profiling
> +Date:		September 2024
> +KernelVersion:	6.11.0
> +Contact:	Adrian Larumbe <adrian.larumbe@collabora.com>
> +Description:
> +		Bitmask to enable drm fdinfo's job profiling measurements.
> +		Valid values are:
> +		0: Don't enable fdinfo job profiling sources.
> +		1: Enable GPU cycle measurements for running jobs.
> +		2: Enable GPU timestamp sampling for running jobs.
> diff --git a/Documentation/gpu/panthor.rst b/Documentation/gpu/panthor.rst
> new file mode 100644
> index 000000000000..cbf5c4429a2d
> --- /dev/null
> +++ b/Documentation/gpu/panthor.rst
> @@ -0,0 +1,46 @@
> +.. SPDX-License-Identifier: GPL-2.0+
> +
> +=========================
> + drm/Panthor CSF driver
> +=========================
> +
> +.. _panfrost-usage-stats:
> +
> +Panthor DRM client usage stats implementation
> +==============================================
> +
> +The drm/Panthor driver implements the DRM client usage stats specification as
> +documented in :ref:`drm-client-usage-stats`.
> +
> +Example of the output showing the implemented key value pairs and entirety of
> +the currently possible format options:
> +
> +::
> +     pos:    0
> +     flags:  02400002
> +     mnt_id: 29
> +     ino:    491
> +     drm-driver:     panthor
> +     drm-client-id:  10
> +     drm-engine-panthor:     111110952750 ns
> +     drm-cycles-panthor:     94439687187
> +     drm-maxfreq-panthor:    1000000000 Hz
> +     drm-curfreq-panthor:    1000000000 Hz
> +     drm-total-memory:       16480 KiB
> +     drm-shared-memory:      0
> +     drm-active-memory:      16200 KiB
> +     drm-resident-memory:    16480 KiB
> +     drm-purgeable-memory:   0
> +
> +Possible `drm-engine-` key names are: `panthor`.
> +`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/panthor/[a-f0-9]*.gpu/profiling
> +
> +Where `N` is a bit mask where cycle and timestamp sampling are respectively
> +enabled by the first and second bits.
> diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
> index 233b265c0819..6f47d9d1d86a 100644
> --- a/drivers/gpu/drm/panthor/panthor_drv.c
> +++ b/drivers/gpu/drm/panthor/panthor_drv.c
> @@ -1513,6 +1513,44 @@ static void panthor_remove(struct platform_device *pdev)
>  	panthor_device_unplug(ptdev);
>  }
>  
> +static ssize_t profiling_show(struct device *dev,
> +			      struct device_attribute *attr,
> +			      char *buf)
> +{
> +	struct panthor_device *ptdev = dev_get_drvdata(dev);
> +
> +	return sysfs_emit(buf, "%d\n", ptdev->profile_mask);
> +}
> +
> +static ssize_t profiling_store(struct device *dev,
> +			       struct device_attribute *attr,
> +			       const char *buf, size_t len)
> +{
> +	struct panthor_device *ptdev = dev_get_drvdata(dev);
> +	u32 value;
> +	int err;
> +
> +	err = kstrtou32(buf, 0, &value);
> +	if (err)
> +		return err;
> +
> +	if ((value & ~PANTHOR_DEVICE_PROFILING_ALL) != 0)
> +		return -EINVAL;
> +
> +	ptdev->profile_mask = value;
> +
> +	return len;
> +}
> +
> +static DEVICE_ATTR_RW(profiling);
> +
> +static struct attribute *panthor_attrs[] = {
> +	&dev_attr_profiling.attr,
> +	NULL,
> +};
> +
> +ATTRIBUTE_GROUPS(panthor);
> +
>  static const struct of_device_id dt_match[] = {
>  	{ .compatible = "rockchip,rk3588-mali" },
>  	{ .compatible = "arm,mali-valhall-csf" },
> @@ -1532,6 +1570,7 @@ static struct platform_driver panthor_driver = {
>  		.name = "panthor",
>  		.pm = pm_ptr(&panthor_pm_ops),
>  		.of_match_table = dt_match,
> +		.dev_groups = panthor_groups,
>  	},
>  };
>