drm/atomic-helper: Add format-conversion state to shadow-plane state

Store an instance of struct drm_format_conv_state in the shadow-plane
state struct drm_shadow_plane_state. Many drivers with shadow planes
use DRM's format helpers to copy or convert the framebuffer data to
backing storage in the scanout buffer. The shadow plane provides the
necessary state and manages the conversion's intermediate buffer memory.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Tested-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231009141018.11291-3-tzimmermann@suse.de

drm/simple-kms: Remove drm_gem_simple_display_pipe_prepare_fb()

The helper drm_gem_simple_display_pipe_prepare_fb() is simple-KMS'
default implementation for prepare_fb. Remove the call from drivers
that set it explicitly. Then inline the helper into the only caller
within simple-kms helpers. No functional changes.

Simple-KMS drivers that implement the prepare_fb callback should call
drm_gem_plane_helper_prepare_fb() directly.

v2:
* fix typo in commit message

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221202125644.7917-2-tzimmermann@suse.de

drm/gem: Implement shadow-plane {begin, end}_fb_access with vmap

Move the vmap code for shadow-plane helpers from prepare_fb to
begin_fb_access helpers. Vunmap is now performed at the end of
the current pageflip, instead of the end of the following pageflip.

Reduces the duration of the mapping from while the framebuffer is
being displayed to just the atomic commit. This is safe as outside
of the pageflip, nothing should access the mapped buffer memory.
Unmapping the framebuffer BO memory early allows to reduce address-
space consumption and possibly allows for evicting the memory pages.

The change is effectively a rename of prepare_fb and cleanup_fb
implementations, plus updates to the shadow-plane init macro. As
there's no longer a prepare_fb helper for shadow planes, atomic
helpers will call drm_gem_plane_helper_prepare_fb() automatically.

v2:
* fix typos in commit message (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221025101737.8874-3-tzimmermann@suse.de

dma-buf-map: Rename to iosys-map

Rename struct dma_buf_map to struct iosys_map and corresponding APIs.
Over time dma-buf-map grew up to more functionality than the one used by
dma-buf: in fact it's just a shim layer to abstract system memory, that
can be accessed via regular load and store, from IO memory that needs to
be acessed via arch helpers.

The idea is to extend this API so it can fulfill other needs, internal
to a single driver. Example: in the i915 driver it's desired to share
the implementation for integrated graphics, which uses mostly system
memory, with discrete graphics, which may need to access IO memory.

The conversion was mostly done with the following semantic patch:

@r1@
@@
- struct dma_buf_map
+ struct iosys_map

@r2@
@@
(
- DMA_BUF_MAP_INIT_VADDR
+ IOSYS_MAP_INIT_VADDR
|
- dma_buf_map_set_vaddr
+ iosys_map_set_vaddr
|
- dma_buf_map_set_vaddr_iomem
+ iosys_map_set_vaddr_iomem
|
- dma_buf_map_is_equal
+ iosys_map_is_equal
|
- dma_buf_map_is_null
+ iosys_map_is_null
|
- dma_buf_map_is_set
+ iosys_map_is_set
|
- dma_buf_map_clear
+ iosys_map_clear
|
- dma_buf_map_memcpy_to
+ iosys_map_memcpy_to
|
- dma_buf_map_incr
+ iosys_map_incr
)

@@
@@
- #include <linux/dma-buf-map.h>
+ #include <linux/iosys-map.h>

Then some files had their includes adjusted and some comments were
update to remove mentions to dma-buf-map.

Since this is not specific to dma-buf anymore, move the documentation to
the "Bus-Independent Device Accesses" section.

v2:
- Squash patches

v3:
- Fix wrong removal of dma-buf.h from MAINTAINERS
- Move documentation from dma-buf.rst to device-io.rst

v4:
- Change documentation title and level

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220204170541.829227-1-lucas.demarchi@intel.com

drm/simpledrm: Support virtual screen sizes

Add constants for the maximum size of the shadow-plane surface
size. Useful for shadow planes with virtual screen sizes. The
current sizes are 4096 scanlines with 4096 pixels each. This
seems reasonable for current hardware, but can be increased as
necessary.

In simpledrm, set the maximum framebuffer size from the constants
for shadow planes. Implements support for virtual screen sizes and
page flipping on the fbdev console.

v3:
* use decimal numbers for shadow-plane constants (Noralf)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211110103702.374-9-tzimmermann@suse.de

drm/gem: Provide offset-adjusted framebuffer BO mappings

Add an additional argument to drm_gem_fb_vmap() to return each BO's
mapping adjusted by the respective offset. Update all callers.

The newly returned values point to the first byite of the data stored
in the framebuffer BOs. Drivers that access the BO data should use it.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210803125928.27780-2-tzimmermann@suse.de

drm: Define DRM_FORMAT_MAX_PLANES

DRM uses a magic number of 4 for the maximum number of planes per color
format. Declare this constant via DRM_FORMAT_MAX_PLANES and update the
related code. Some code depends on the length of arrays that are now
declared with DRM_FORMAT_MAX_PLANES. Convert it from '4' to ARRAY_SIZE.

v2:
* mention usage of ARRAY_SIZE() in the commit message (Maxime)
* also fix error handling in drm_gem_fb_init_with_funcs()
(kernel test robot)
* include <drm/drm_fourcc.h> for DRM_FORMAT_MAX_PLANES

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210730183511.20080-2-tzimmermann@suse.de

drm/gem: Export implementation of shadow-plane helpers

Export the implementation of duplicate, destroy and reset helpers for
shadow-buffered plane state. Useful for drivers that subclass struct
drm_shadow_plane_state.

The exported functions are wrappers around plane-state implementation,
but using them is the correct thing to do for drivers.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210705074633.9425-2-tzimmermann@suse.de

drm/gem: Move drm_gem_fb_prepare_fb() to GEM atomic helpers

The function drm_gem_fb_prepare_fb() is a helper for atomic modesetting,
but currently located next to framebuffer helpers. Move it to GEM atomic
helpers, rename it slightly and adopt the drivers. Same for the rsp
simple-pipe helper.

Compile-tested with x86-64, aarch64 and arm. The patch is fairly large,
but there are no functional changes.

v3:
* remove out-comented line in drm_gem_framebuffer_helper.h
(Maxime)
v2:
* rename to drm_gem_plane_helper_prepare_fb() (Daniel)
* add tutorial-style documentation

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210222141756.7864-1-tzimmermann@suse.de

drm/gem: Export helpers for shadow-buffered planes

Export the helpers for shadow-buffered planes. These will be used by
several drivers.

v3:
* fix documentation typos and formatting (Daniel)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210209121042.24098-2-tzimmermann@suse.de

drm: Add additional atomic helpers for shadow-buffered planes

Several drivers use GEM buffer objects as shadow buffers for the actual
framebuffer memory. Right now, drivers do these vmap operations in their
commit tail, which is actually not allowed by the locking rules for
the dma-buf reservation lock. The involved BO has to be vmapped in the
plane's prepare_fb callback and vunmapped in cleanup_fb.

This patch introduces atomic helpers for such shadow planes. Plane
functions manage the plane state for shadow planes. The provided
implementations for prepare_fb and cleanup_fb vmap and vunmap all BOs of
struct drm_plane_state.fb. The mappings are afterwards available in the
plane's commit-tail functions.

For now, all rsp drivers use the simple KMS helpers, so we add the plane
callbacks and wrappers for simple KMS. The internal plane functions can
later be exported as needed.

v3:
* documentation fixes
v2:
* make duplicate_state interface compatible with
struct drm_plane_funcs

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210208115538.6430-4-tzimmermann@suse.de