[v7,00/10] Support GEM object mappings from I/O memory

DRM's fbdev console uses regular load and store operations to update
framebuffer memory. The bochs driver on sparc64 requires the use of
I/O-specific load and store operations. We have a workaround, but need
a long-term solution to the problem.

This patchset changes GEM's vmap/vunmap interfaces to forward pointers
of type struct dma_buf_map and updates the generic fbdev emulation to
use them correctly. This enables I/O-memory operations on all framebuffers
that require and support them.

Patches #1 to #4 prepare VRAM helpers and drivers.

Next is the update of the GEM vmap functions. Patch #5 adds vmap and vunmap
that is usable with TTM-based GEM drivers, and patch #6 updates GEM's
vmap/vunmap callback to forward instances of type struct dma_buf_map. While
the patch touches many files throughout the DRM modules, the applied changes
are mostly trivial interface fixes. Several TTM-based GEM drivers now use
the new vmap code. Patch #7 updates GEM's internal vmap/vunmap functions to
forward struct dma_buf_map.

With struct dma_buf_map propagated through the layers, patches #8 to #10
convert DRM clients and generic fbdev emulation to use it. Updating the
fbdev framebuffer will select the correct functions, either for system or
I/O memory.

There is also a set of IGT testcases for fbdev at [1]. Reading and writting
fbdev device files has several corner cases near the EOF that the tests cover
as well. The original fbdev code has different semantics with the different
implementations (sys, cfb). Patch #10 and the testcases intend to harmonize
the behaviour and serve as a reference.

v7:
	* return number of read/written bytes in fbdev code; if any
	* init QXL cursor from BO buffer (kernel test robot)
	* use min_t(size_t,) (kernel test robot)
v6:
	* don't call page_to_phys() on fbdev framebuffers in I/O memory;
	  warn instead (Daniel)
v5:
	* rebase onto latest TTM changes (Christian)
	* support TTM premapped memory correctly (Christian)
	* implement fb_read/fb_write internally (Sam, Daniel)
	* cleanups
v4:
	* provide TTM vmap/vunmap plus GEM helpers and convert drivers
	  over (Christian, Daniel)
	* remove several empty functions
	* more TODOs and documentation (Daniel)
v3:
	* recreate the whole patchset on top of struct dma_buf_map
v2:
	* RFC patchset

[1] https://gitlab.freedesktop.org/tzimmermann/igt-gpu-tools/-/merge_requests/1

Thomas Zimmermann (10):
  drm/vram-helper: Remove invariant parameters from internal kmap
    function
  drm/cma-helper: Remove empty drm_gem_cma_prime_vunmap()
  drm/etnaviv: Remove empty etnaviv_gem_prime_vunmap()
  drm/exynos: Remove empty exynos_drm_gem_prime_{vmap,vunmap}()
  drm/ttm: Add vmap/vunmap to TTM and TTM GEM helpers
  drm/gem: Use struct dma_buf_map in GEM vmap ops and convert GEM
    backends
  drm/gem: Update internal GEM vmap/vunmap interfaces to use struct
    dma_buf_map
  drm/gem: Store client buffer mappings as struct dma_buf_map
  dma-buf-map: Add memcpy and pointer-increment interfaces
  drm/fb_helper: Support framebuffers in I/O memory

 Documentation/gpu/todo.rst                  |  37 ++-
 drivers/gpu/drm/Kconfig                     |   2 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c |  36 ---
 drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.h |   2 -
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c     |   5 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_object.h  |   1 -
 drivers/gpu/drm/ast/ast_cursor.c            |  27 +--
 drivers/gpu/drm/ast/ast_drv.h               |   7 +-
 drivers/gpu/drm/bochs/bochs_kms.c           |   1 -
 drivers/gpu/drm/drm_client.c                |  38 +--
 drivers/gpu/drm/drm_fb_helper.c             | 250 ++++++++++++++++++--
 drivers/gpu/drm/drm_gem.c                   |  29 ++-
 drivers/gpu/drm/drm_gem_cma_helper.c        |  27 +--
 drivers/gpu/drm/drm_gem_shmem_helper.c      |  48 ++--
 drivers/gpu/drm/drm_gem_ttm_helper.c        |  38 +++
 drivers/gpu/drm/drm_gem_vram_helper.c       | 117 +++++----
 drivers/gpu/drm/drm_internal.h              |   5 +-
 drivers/gpu/drm/drm_prime.c                 |  14 +-
 drivers/gpu/drm/etnaviv/etnaviv_drv.h       |   3 +-
 drivers/gpu/drm/etnaviv/etnaviv_gem.c       |   1 -
 drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c |  12 +-
 drivers/gpu/drm/exynos/exynos_drm_gem.c     |  12 -
 drivers/gpu/drm/exynos/exynos_drm_gem.h     |   2 -
 drivers/gpu/drm/lima/lima_gem.c             |   6 +-
 drivers/gpu/drm/lima/lima_sched.c           |  11 +-
 drivers/gpu/drm/mgag200/mgag200_mode.c      |  10 +-
 drivers/gpu/drm/nouveau/Kconfig             |   1 +
 drivers/gpu/drm/nouveau/nouveau_bo.h        |   2 -
 drivers/gpu/drm/nouveau/nouveau_gem.c       |   6 +-
 drivers/gpu/drm/nouveau/nouveau_gem.h       |   2 -
 drivers/gpu/drm/nouveau/nouveau_prime.c     |  20 --
 drivers/gpu/drm/panfrost/panfrost_perfcnt.c |  14 +-
 drivers/gpu/drm/qxl/qxl_display.c           |  15 +-
 drivers/gpu/drm/qxl/qxl_draw.c              |  14 +-
 drivers/gpu/drm/qxl/qxl_drv.h               |  11 +-
 drivers/gpu/drm/qxl/qxl_object.c            |  31 ++-
 drivers/gpu/drm/qxl/qxl_object.h            |   2 +-
 drivers/gpu/drm/qxl/qxl_prime.c             |  12 +-
 drivers/gpu/drm/radeon/radeon.h             |   1 -
 drivers/gpu/drm/radeon/radeon_gem.c         |   7 +-
 drivers/gpu/drm/radeon/radeon_prime.c       |  20 --
 drivers/gpu/drm/rockchip/rockchip_drm_gem.c |  22 +-
 drivers/gpu/drm/rockchip/rockchip_drm_gem.h |   4 +-
 drivers/gpu/drm/tiny/cirrus.c               |  10 +-
 drivers/gpu/drm/tiny/gm12u320.c             |  10 +-
 drivers/gpu/drm/ttm/ttm_bo_util.c           |  72 ++++++
 drivers/gpu/drm/udl/udl_modeset.c           |   8 +-
 drivers/gpu/drm/vboxvideo/vbox_mode.c       |  11 +-
 drivers/gpu/drm/vc4/vc4_bo.c                |   7 +-
 drivers/gpu/drm/vc4/vc4_drv.h               |   2 +-
 drivers/gpu/drm/vgem/vgem_drv.c             |  16 +-
 drivers/gpu/drm/vkms/vkms_plane.c           |  15 +-
 drivers/gpu/drm/vkms/vkms_writeback.c       |  22 +-
 drivers/gpu/drm/xen/xen_drm_front_gem.c     |  18 +-
 drivers/gpu/drm/xen/xen_drm_front_gem.h     |   6 +-
 include/drm/drm_client.h                    |   7 +-
 include/drm/drm_gem.h                       |   5 +-
 include/drm/drm_gem_cma_helper.h            |   3 +-
 include/drm/drm_gem_shmem_helper.h          |   4 +-
 include/drm/drm_gem_ttm_helper.h            |   6 +
 include/drm/drm_gem_vram_helper.h           |  14 +-
 include/drm/drm_mode_config.h               |  12 -
 include/drm/ttm/ttm_bo_api.h                |  28 +++
 include/linux/dma-buf-map.h                 |  93 +++++++-
 64 files changed, 856 insertions(+), 438 deletions(-)

--
2.29.0