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Mon, 24 Oct 2022 00:52:21 -0700 (PDT) MIME-Version: 1.0 References: <20221022214622.18042-1-ogabbay@kernel.org> <20221022214622.18042-3-ogabbay@kernel.org> In-Reply-To: From: Dave Airlie Date: Mon, 24 Oct 2022 17:52:10 +1000 Message-ID: Subject: Re: [RFC PATCH 2/3] drm: define new accel major and register it To: Oded Gabbay Cc: Greg Kroah-Hartman , Daniel Vetter , Arnd Bergmann , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Jason Gunthorpe , John Hubbard , Alex Deucher , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Yuji Ishikawa , Jiho Chu , Daniel Stone , Tvrtko Ursulin , Jeffrey Hugo , Christoph Hellwig , Kevin Hilman , Jagan Teki , Jacek Lawrynowicz , Maciej Kwapulinski Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 24 Oct 2022 at 17:23, Oded Gabbay wrote: > > On Sun, Oct 23, 2022 at 3:40 PM Greg Kroah-Hartman > wrote: > > > > On Sun, Oct 23, 2022 at 12:46:21AM +0300, Oded Gabbay wrote: > > > The accelerator devices will be exposed to the user space with a new, > > > dedicated major number - 261. > > > > > > The drm core registers the new major number as a char device and create > > > corresponding sysfs and debugfs root entries, same as for the drm major. > > > > > > In case CONFIG_ACCEL is not selected, this code is not compiled in. > > > > > > Signed-off-by: Oded Gabbay > > > --- > > > Documentation/admin-guide/devices.txt | 5 +++ > > > drivers/gpu/drm/drm_drv.c | 45 +++++++++++++++++++++++ > > > drivers/gpu/drm/drm_internal.h | 3 ++ > > > drivers/gpu/drm/drm_sysfs.c | 52 +++++++++++++++++++++++++++ > > > include/drm/drm_ioctl.h | 1 + > > > 5 files changed, 106 insertions(+) > > > > > > diff --git a/Documentation/admin-guide/devices.txt b/Documentation/admin-guide/devices.txt > > > index 9764d6edb189..06c525e01ea5 100644 > > > --- a/Documentation/admin-guide/devices.txt > > > +++ b/Documentation/admin-guide/devices.txt > > > @@ -3080,6 +3080,11 @@ > > > ... > > > 255 = /dev/osd255 256th OSD Device > > > > > > + 261 char Compute Acceleration Devices > > > + 0 = /dev/accel/accel0 First acceleration device > > > + 1 = /dev/accel/accel1 Second acceleration device > > > + ... > > > + > > > 384-511 char RESERVED FOR DYNAMIC ASSIGNMENT > > > Character devices that request a dynamic allocation of major > > > number will take numbers starting from 511 and downward, > > > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c > > > index 8214a0b1ab7f..b58ffb1433d6 100644 > > > --- a/drivers/gpu/drm/drm_drv.c > > > +++ b/drivers/gpu/drm/drm_drv.c > > > @@ -67,6 +67,10 @@ static bool drm_core_init_complete; > > > > > > static struct dentry *drm_debugfs_root; > > > > > > +#ifdef CONFIG_ACCEL > > > +static struct dentry *accel_debugfs_root; > > > +#endif > > > + > > > DEFINE_STATIC_SRCU(drm_unplug_srcu); > > > > > > /* > > > @@ -1031,9 +1035,19 @@ static const struct file_operations drm_stub_fops = { > > > .llseek = noop_llseek, > > > }; > > > > > > +static void accel_core_exit(void) > > > +{ > > > +#ifdef CONFIG_ACCEL > > > + unregister_chrdev(ACCEL_MAJOR, "accel"); > > > + debugfs_remove(accel_debugfs_root); > > > + accel_sysfs_destroy(); > > > +#endif > > > +} > > > > Why is all of this in drm_drv.c? > > > > Why not put it in drm/accel/accel.c or something like that? Then put > > the proper stuff into a .h file and then you have no #ifdef in the .c > > files. > I thought about that, adding an accel.c in drivers/accel/ and putting > this code there. > Eventually I thought that for two functions it's not worth it, but I > guess that in addition to the reason you gave, one can argue that > there will probably be more code in that file anyway, so why not open > it now. > I'll change this if no one else thinks otherwise. Seems like a good idea to start doing it now, might make things easier to keep separated. Dave.