[Lima] [PATCH 0/2] Lima DRM driver

Koenig, Christian Christian.Koenig at amd.com
Thu Feb 7 19:14:36 UTC 2019


Am 07.02.19 um 16:33 schrieb Qiang Yu:
> On Thu, Feb 7, 2019 at 5:39 PM Christian König
> <ckoenig.leichtzumerken at gmail.com> wrote:
>> Am 07.02.19 um 10:09 schrieb Daniel Vetter:
>>> On Wed, Feb 06, 2019 at 09:14:55PM +0800, Qiang Yu wrote:
>>>> Kernel DRM driver for ARM Mali 400/450 GPUs.
>>>>
>>>> Since last RFC, all feedback has been addressed. Most Mali DTS
>>>> changes are already upstreamed by SoC maintainers. The kernel
>>>> driver and user-kernel interface are quite stable for several
>>>> months, so I think it's ready to be upstreamed.
>>>>
>>>> This implementation mainly take amdgpu DRM driver as reference.
>>>>
>>>> - Mali 4xx GPUs have two kinds of processors GP and PP. GP is for
>>>>     OpenGL vertex shader processing and PP is for fragment shader
>>>>     processing. Each processor has its own MMU so prcessors work in
>>>>     virtual address space.
>>>> - There's only one GP but multiple PP (max 4 for mali 400 and 8
>>>>     for mali 450) in the same mali 4xx GPU. All PPs are grouped
>>>>     togather to handle a single fragment shader task divided by
>>>>     FB output tiled pixels. Mali 400 user space driver is
>>>>     responsible for assign target tiled pixels to each PP, but mali
>>>>     450 has a HW module called DLBU to dynamically balance each
>>>>     PP's load.
>>>> - User space driver allocate buffer object and map into GPU
>>>>     virtual address space, upload command stream and draw data with
>>>>     CPU mmap of the buffer object, then submit task to GP/PP with
>>>>     a register frame indicating where is the command stream and misc
>>>>     settings.
>>>> - There's no command stream validation/relocation due to each user
>>>>     process has its own GPU virtual address space. GP/PP's MMU switch
>>>>     virtual address space before running two tasks from different
>>>>     user process. Error or evil user space code just get MMU fault
>>>>     or GP/PP error IRQ, then the HW/SW will be recovered.
>>>> - Use TTM as MM. TTM_PL_TT type memory is used as the content of
>>>>     lima buffer object which is allocated from TTM page pool. all
>>>>     lima buffer object gets pinned with TTM_PL_FLAG_NO_EVICT when
>>>>     allocation, so there's no buffer eviction and swap for now.
>>> All other render gpu drivers that have unified memory (aka is on the SoC)
>>> use GEM directly, with some of the helpers we have. So msm, etnaviv, vc4
>>> (and i915 is kinda the same too really). TTM makes sense if you have some
>>> discrete memory to manage, but imo not in any other place really.
>>>
>>> What's the design choice behind this?
>> Agree that this seems unnecessary complicated.
>>
>> Additional to that why do you use TTM_PL_FLAG_NO_EVICT? That is a
>> serious show stopper and as far as I can of hand see completely unnecessary.
> Just for simplification. There's no eviction for unified mem, but swap will be
> introduced when this flag is not set. So I have to do vm table clear/restore and
> call bo validation which I plan to implement in the future.

Ok, well if you are using GEM or GEM+TTM is up to you. I just think 
using GEM directly like Daniel suggest would be simpler in the long term.

But support for eviction is a serious prerequisite to allowing this 
upstream. So that is really something you need to clean up first.

Regards,
Christian.

>
> Thanks,
> Qiang
>
>> Christian.
>>
>>>   From an upstream pov having all soc gpu drivers use similar approaches
>>> should help with shared infrastructure and stuff like that.
>>>
>>> Another one: What's the plan with extending this to panfrost? Or are the
>>> architectures for command submission totally different, and we'll need
>>> separate kernel drivers for utgard/midgard/bifrost?
>>>
>>> Thanks, Daniel
>>>
>>>> - Use drm_sched for GPU task schedule. Each OpenGL context should
>>>>     have a lima context object in the kernel to distinguish tasks
>>>>     from different user. drm_sched gets task from each lima context
>>>>     in a fair way.
>>>>
>>>> This patch serial is based on 5.0-rc5 and squash all the commits.
>>>> For whole history of this driver's development, see:
>>>> https://gitlab.freedesktop.org/lima/linux/commits/lima-5.0-rc5
>>>> https://gitlab.freedesktop.org/lima/linux/commits/lima-4.17-rc4
>>>>
>>>> Mesa driver is still in development and not ready for daily usage,
>>>> but can run some simple tests like kmscube and glamrk2, and some
>>>> single full screen application like kodi-gbm, see:
>>>> https://gitlab.freedesktop.org/lima/mesa
>>>>
>>>> [rfc]
>>>> https://lists.freedesktop.org/archives/dri-devel/2018-May/177314.html
>>>>
>>>> Lima Project Developers (1):
>>>>     drm/lima: driver for ARM Mali4xx GPUs
>>>>
>>>> Qiang Yu (1):
>>>>     drm/fourcc: add ARM tiled format modifier
>>>>
>>>>    drivers/gpu/drm/Kconfig               |   2 +
>>>>    drivers/gpu/drm/Makefile              |   1 +
>>>>    drivers/gpu/drm/lima/Kconfig          |  10 +
>>>>    drivers/gpu/drm/lima/Makefile         |  22 ++
>>>>    drivers/gpu/drm/lima/lima_bcast.c     |  46 +++
>>>>    drivers/gpu/drm/lima/lima_bcast.h     |  14 +
>>>>    drivers/gpu/drm/lima/lima_ctx.c       | 124 +++++++
>>>>    drivers/gpu/drm/lima/lima_ctx.h       |  33 ++
>>>>    drivers/gpu/drm/lima/lima_device.c    | 384 ++++++++++++++++++++
>>>>    drivers/gpu/drm/lima/lima_device.h    | 116 ++++++
>>>>    drivers/gpu/drm/lima/lima_dlbu.c      |  56 +++
>>>>    drivers/gpu/drm/lima/lima_dlbu.h      |  18 +
>>>>    drivers/gpu/drm/lima/lima_drv.c       | 459 ++++++++++++++++++++++++
>>>>    drivers/gpu/drm/lima/lima_drv.h       |  59 ++++
>>>>    drivers/gpu/drm/lima/lima_gem.c       | 485 +++++++++++++++++++++++++
>>>>    drivers/gpu/drm/lima/lima_gem.h       |  25 ++
>>>>    drivers/gpu/drm/lima/lima_gem_prime.c | 144 ++++++++
>>>>    drivers/gpu/drm/lima/lima_gem_prime.h |  18 +
>>>>    drivers/gpu/drm/lima/lima_gp.c        | 280 +++++++++++++++
>>>>    drivers/gpu/drm/lima/lima_gp.h        |  16 +
>>>>    drivers/gpu/drm/lima/lima_l2_cache.c  |  79 +++++
>>>>    drivers/gpu/drm/lima/lima_l2_cache.h  |  14 +
>>>>    drivers/gpu/drm/lima/lima_mmu.c       | 135 +++++++
>>>>    drivers/gpu/drm/lima/lima_mmu.h       |  16 +
>>>>    drivers/gpu/drm/lima/lima_object.c    | 103 ++++++
>>>>    drivers/gpu/drm/lima/lima_object.h    |  72 ++++
>>>>    drivers/gpu/drm/lima/lima_pmu.c       |  61 ++++
>>>>    drivers/gpu/drm/lima/lima_pmu.h       |  12 +
>>>>    drivers/gpu/drm/lima/lima_pp.c        | 419 ++++++++++++++++++++++
>>>>    drivers/gpu/drm/lima/lima_pp.h        |  19 +
>>>>    drivers/gpu/drm/lima/lima_regs.h      | 298 ++++++++++++++++
>>>>    drivers/gpu/drm/lima/lima_sched.c     | 486 ++++++++++++++++++++++++++
>>>>    drivers/gpu/drm/lima/lima_sched.h     | 108 ++++++
>>>>    drivers/gpu/drm/lima/lima_ttm.c       | 319 +++++++++++++++++
>>>>    drivers/gpu/drm/lima/lima_ttm.h       |  24 ++
>>>>    drivers/gpu/drm/lima/lima_vm.c        | 354 +++++++++++++++++++
>>>>    drivers/gpu/drm/lima/lima_vm.h        |  59 ++++
>>>>    include/uapi/drm/drm_fourcc.h         |   9 +
>>>>    include/uapi/drm/lima_drm.h           | 193 ++++++++++
>>>>    39 files changed, 5092 insertions(+)
>>>>    create mode 100644 drivers/gpu/drm/lima/Kconfig
>>>>    create mode 100644 drivers/gpu/drm/lima/Makefile
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_bcast.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_bcast.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_ctx.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_ctx.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_device.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_device.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_dlbu.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_dlbu.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_drv.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_drv.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_gem.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_gem.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_gem_prime.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_gem_prime.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_gp.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_gp.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_l2_cache.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_l2_cache.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_mmu.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_mmu.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_object.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_object.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_pmu.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_pmu.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_pp.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_pp.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_regs.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_sched.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_sched.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_ttm.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_ttm.h
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_vm.c
>>>>    create mode 100644 drivers/gpu/drm/lima/lima_vm.h
>>>>    create mode 100644 include/uapi/drm/lima_drm.h
>>>>
>>>> --
>>>> 2.17.1
>>>>



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