Re: [PATCH 0/2] Lima DRM driver

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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.

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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