• Aaron Plattner's avatar
    drm: add prime helpers · 89177644
    Aaron Plattner authored
    Instead of reimplementing all of the dma_buf functionality in every driver,
    create helpers drm_prime_import and drm_prime_export that implement them in
    terms of new, lower-level hook functions:
    
      gem_prime_pin: callback when a buffer is created, used to pin buffers into GTT
      gem_prime_get_sg_table: convert a drm_gem_object to an sg_table for export
      gem_prime_import_sg_table: convert an sg_table into a drm_gem_object
      gem_prime_vmap, gem_prime_vunmap: map and unmap an object
    
    These hooks are optional; drivers can opt in by using drm_gem_prime_import and
    drm_gem_prime_export as the .gem_prime_import and .gem_prime_export fields of
    struct drm_driver.
    
    v2:
    - Drop .begin_cpu_access.  None of the drivers this code replaces implemented
      it.  Having it here was a leftover from when I was trying to include i915 in
      this rework.
    - Use mutex_lock instead of mutex_lock_interruptible, as these three drivers
      did.  This patch series shouldn't change that behavior.
    - Rename helpers to gem_prime_get_sg_table and gem_prime_import_sg_table.
      Rename struct sg_table* variables to 'sgt' for clarity.
    - Update drm.tmpl for these new hooks.
    
    v3:
    - Pass the vaddr down to the driver.  This lets drivers that just call vunmap on
      the pointer avoid having to store the pointer in their GEM private structures.
    - Move documentation into a /** DOC */ comment in drm_prime.c and include it in
      drm.tmpl with a !P line.  I tried to use !F lines to include documentation of
      the individual functions from drmP.h, but the docproc / kernel-doc scripts
      barf on that file, so hopefully this is good enough for now.
    - apply refcount fix from commit be8a42ae
      ("drm/prime: drop reference on imported dma-buf come from gem")
    Signed-off-by: default avatarAaron Plattner <aplattner@nvidia.com>
    Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
    Cc: David Airlie <airlied@linux.ie>
    Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
    89177644
drm.tmpl 115 KB