[PATCH v3 0/6] drm/vkms: introduce plane rotation property

[Maíra Canal]

This patchset implements all possible rotation value in vkms. All operations
were implemented by software by changing the way the pixels are read. The way
the blending is performed can be depicted as:

- rotate-0:
    (x) ---->
    ----------------------
(y) |                    |
  | |                    |
  | |                    |
  ˇ |                    |
    ----------------------

- rotate-90:
    <---- (y)
    ----------------------
(x) |                    |
  | |                    |
  | |                    |
  ˇ |                    |
    ----------------------

- rotate-180:
    <---- (x)
    ----------------------
(y) |                    |
  ^ |                    |
  | |                    |
  | |                    |
    ----------------------

- rotate-270:
    (y) ---->
    ----------------------
(x) |                    |
  ^ |                    |
  | |                    |
  | |                    |
    ----------------------

- reflect-x:
    <---- (x)
    ----------------------
(y) |                    |
  | |                    |
  | |                    |
  ˇ |                    |
    ----------------------

- reflect-y:
    (x) ---->
    ----------------------
(y) |                    |
  ^ |                    |
  | |                    |
  | |                    |
    ----------------------

The patchset was tested with IGT's kms_rotation_crc tests and also with some
additional tests [1] for the reflection operations.

In order to avoid code duplication, I introduced a patch that isolates the
pixel format convertion and wraps it in a single loop.

v1 -> v2: https://lore.kernel.org/dri-devel/20230406130138.70752-1-mcanal@igalia.com/T/

* Add patch to isolate pixel format conversion (Arthur Grillo).

v2 -> v3: https://lore.kernel.org/dri-devel/20230414135151.75975-1-mcanal@igalia.com/T/

* Use cpp to calculate pixel size instead of hard-coding (Arthur Grillo).
* Don't use the x coordinate in the pixel_read functions (Arthur Grillo).
* Use drm_rotate_simplify() to avoid hard-coding rotate-180 (Ville Syrjälä).
* Use u8* to input the src_pixels instead of using u16*.

[1] https://patchwork.freedesktop.org/series/116025/

Best Regards,
- Maíra Canal

Maíra Canal (6):
  drm/vkms: isolate pixel conversion functionality
  drm/vkms: add rotate-0 and reflect-x property
  drm/vkms: add reflect-y and rotate-180 property
  drm/vkms: add rotate-90 property
  drm/vkms: add rotate-270 property
  drm/vkms: drop "Rotation" TODO

 Documentation/gpu/vkms.rst           |   2 +-
 drivers/gpu/drm/vkms/vkms_composer.c |  71 +++++++++++---
 drivers/gpu/drm/vkms/vkms_drv.h      |   5 +-
 drivers/gpu/drm/vkms/vkms_formats.c  | 142 +++++++++++++--------------
 drivers/gpu/drm/vkms/vkms_formats.h  |   2 +-
 drivers/gpu/drm/vkms/vkms_plane.c    |  15 ++-
 6 files changed, 148 insertions(+), 89 deletions(-)

-- 
2.39.2