[Lima] [PATCH 0/2] Lima DRM driver
Qiang Yu
yuq825 at gmail.com
Thu Feb 7 15:21:52 UTC 2019
On Thu, Feb 7, 2019 at 5:09 PM Daniel Vetter <daniel at ffwll.ch> wrote:
>
> 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?
To be honest, it's just because TTM offers more helpers. I did implement
a GEM way with cma alloc at the beginning. But when implement paged mem,
I found TTM has mem pool alloc, sync and mmap related helpers which covers
much of my existing code. It's totally possible with GEM, but not as easy as
TTM to me. And virtio-gpu seems an example to use TTM without discrete
mem. Shouldn't TTM a super set of both unified mem and discrete mem?
>
> From an upstream pov having all soc gpu drivers use similar approaches
> should help with shared infrastructure and stuff like that.
Hope GEM gets more helpers now if Iima have to use it.
>
> 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?
+ Alyssa & Rob
There is a gitlab issue about sharing kernel driver:
https://gitlab.freedesktop.org/panfrost/linux/issues/1
But seems utgard (discrete shader arch) really differs with midgard/bifrost
(unified shader arch), so that ARM also have different official kernel drivers.
Thanks,
Qiang
>
> 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
> >
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
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