drm/msm: fbdev: Calculate buffer geometry with format helpers

Replace the geometry and size calculation in msm's fbdev emulation
with DRM format helpers. This consists of a 4CC lookup from the fbdev
parameters, format lookup, pitch calculation and size calculation.
Then allocate the GEM buffer object for the framebuffer memory from
the calculated size.

Explicitly align the size of the allocated GEM buffer object to full
pages. The contained memory is the framebuffer memory as seen by fbdev.
The page alignment is required for mmap.

v2:
- clarify the page alignment of the buffer size (Dmitry)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/733885/
Link: https://lore.kernel.org/r/20260618141249.151338-5-tzimmermann@suse.de
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
This commit is contained in:
Thomas Zimmermann 2026-06-18 16:11:35 +02:00 • committed by Dmitry Baryshkov
commit 6cf3fb14f3
2 changed files with 12 additions and 21 deletions