From: Arnd Bergmann <arnd@arndb.de>
To: "Christian König" <christian.koenig@amd.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>,
David Airlie <airlied@linux.ie>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linaro-mm-sig@lists.linaro.org,
Cai Huoqing <cai.huoqing@linux.dev>,
dri-devel <dri-devel@lists.freedesktop.org>,
Sumit Semwal <sumit.semwal@linaro.org>,
Linux Media Mailing List <linux-media@vger.kernel.org>
Subject: Re: [Linaro-mm-sig] Re: [PATCH v2 4/4] drm/nvdla/uapi: Add UAPI of NVDLA driver
Date: Tue, 26 Apr 2022 12:50:50 +0200 [thread overview]
Message-ID: <CAK8P3a2w1t7Sk897u0ndD66Lwp5a4DuOqqQLN4yHSg=JmrpOHQ@mail.gmail.com> (raw)
In-Reply-To: <618a4f53-0998-1e6b-e32b-8bf2d3057cec@amd.com>
On Tue, Apr 26, 2022 at 8:31 AM Christian König
<christian.koenig@amd.com> wrote:
> Am 26.04.22 um 08:08 schrieb Cai Huoqing:
> > The NVIDIA Deep Learning Accelerator (NVDLA) is an open source IP
> > which is integrated into NVIDIA Jetson AGX Xavier,
> > so add UAPI of this driver.
> >
> > Signed-off-by: Cai Huoqing <cai.huoqing@linux.dev>
I saw the reply but no the original mail, so I'll comment here.
> > +
> > +#if !defined(__KERNEL__)
> > +#define __user
> > +#endif
This is done in the 'make headers_install' step, no need to define it
separately.
> > +#define NVDLA_NO_TIMEOUT (0xffffffff)
> > + __u32 timeout;
>
> What format does that timeout value have?
>
> In general it is best practice to have absolute 64bit nanosecond
> timeouts (to be used with ktime inside the kernel) so that restarting
> interrupted IOCTLs works smooth.
When using absolute values, one also needs to decide whether this should be
realtime, monotonic or boottime and document the decision.
> > + * struct nvdla_submit_args structure for task submit
> > + *
> > + * @tasks pointer to array of struct nvdla_ioctl_submit_task
> > + * @num_tasks number of entries in tasks
> > + * @flags flags for task submit, no flags defined yet
> > + * @version version of task structure
> > + *
> > + */
> > +struct nvdla_submit_args {
> > + __u64 tasks;
> > + __u16 num_tasks;
> > +#define NVDLA_MAX_TASKS_PER_SUBMIT 24
> > +#define NVDLA_SUBMIT_FLAGS_ATOMIC (1 << 0)
>
> Well that "no flags defined yet" from the comment above is probably
> outdated :)
> > + __u16 flags;
> > + __u32 version;
> > +};
Versioned interfaces are usually a bad idea. If you introduce an ioctl command,
it should generally keep working. If you ever need to change the interface, just
use a new command number for the new version.
> > +/**
> > + * struct nvdla_gem_create_args for allocating DMA buffer through GEM
> > + *
> > + * @handle handle updated by kernel after allocation
> > + * @flags implementation specific flags
> > + * @size size of buffer to allocate
> > + */
> > +struct nvdla_gem_create_args {
> > + __u32 handle;
> > + __u32 flags;
> > + __u64 size;
> > +};
> > +
> > +/**
> > + * struct nvdla_gem_map_offset_args for mapping DMA buffer
> > + *
> > + * @handle handle of the buffer
> > + * @reserved reserved for padding
> > + * @offset offset updated by kernel after mapping
> > + */
> > +struct nvdla_gem_map_offset_args {
> > + __u32 handle;
> > + __u32 reserved;
> > + __u64 offset;
> > +};
> > +
> > +#define DRM_NVDLA_SUBMIT 0x00
> > +#define DRM_NVDLA_GEM_CREATE 0x01
> > +#define DRM_NVDLA_GEM_MMAP 0x02
Is this an actual mmap() call, or something that needs to be done before the
mmap()? Is the 'handle' a file descriptor or some internal number?
Arnd
next prev parent reply other threads:[~2022-04-26 11:03 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-26 6:07 [PATCH v2 0/4] drm/nvdla: Add driver support for NVDLA Cai Huoqing
2022-04-26 6:07 ` [PATCH v2 1/4] MAINTAINERS: Add the driver info of the NVDLA Cai Huoqing
2022-04-26 6:07 ` [PATCH v2 2/4] drm/nvdla: Add driver support for NVDLA Cai Huoqing
2022-04-28 15:18 ` Thierry Reding
2022-04-28 15:19 ` Thierry Reding
2022-04-26 6:08 ` [PATCH v2 3/4] drm/nvdla: Add register head file of NVDLA Cai Huoqing
2022-04-28 14:31 ` Thierry Reding
2022-04-26 6:08 ` [PATCH v2 4/4] drm/nvdla/uapi: Add UAPI of NVDLA driver Cai Huoqing
2022-04-26 6:31 ` Christian König
2022-04-26 8:23 ` Cai Huoqing
2022-04-26 8:29 ` Christian König
2022-04-28 14:45 ` Thierry Reding
2022-04-29 3:58 ` Cai Huoqing
2022-04-26 10:50 ` Arnd Bergmann [this message]
2022-04-26 12:24 ` [Linaro-mm-sig] " Cai Huoqing
2022-04-26 12:38 ` Arnd Bergmann
2022-04-26 10:12 ` kernel test robot
2022-04-26 11:23 ` kernel test robot
2022-04-28 14:40 ` Thierry Reding
2022-04-28 14:10 ` [PATCH v2 0/4] drm/nvdla: Add driver support for NVDLA Thierry Reding
2022-04-28 15:56 ` Mikko Perttunen
2022-04-28 16:35 ` Jon Hunter
2022-04-29 3:37 ` Cai Huoqing
2022-04-29 3:28 ` Cai Huoqing
2022-05-02 17:04 ` Thierry Reding
2022-05-07 9:05 ` Cai Huoqing
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