On Tue, 3 Sep 2024 21:25:38 +0100
Adrián Larumbe <adrian.larumbe@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx>
> ---
> Documentation/gpu/panthor.rst | 46 +++++++++++++++++++++++++++
> drivers/gpu/drm/panthor/panthor_drv.c | 39 +++++++++++++++++++++++
> 2 files changed, 85 insertions(+)
> create mode 100644 Documentation/gpu/panthor.rst
>
> 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.
This should probably be documented in
Documentation/ABI/testing/sysfs-driver-panthor too.
> diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
> index e18838754963..26475db96c41 100644
> --- a/drivers/gpu/drm/panthor/panthor_drv.c
> +++ b/drivers/gpu/drm/panthor/panthor_drv.c
> @@ -1450,6 +1450,44 @@ 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" },
> @@ -1469,6 +1507,7 @@ static struct platform_driver panthor_driver = {
> .name = "panthor",
> .pm = pm_ptr(&panthor_pm_ops),
> .of_match_table = dt_match,
> + .dev_groups = panthor_groups,
> },
> };
>
