linux.git/drivers/gpu/drm/tiny/repaper.c, branch v6.12.80

drm/repaper: fix integer overflows in repeat functions

2025-04-25T08:47:57+00:00

commit 4d098000ac193f359e6b8ca4801dbdbd6a27b41f upstream.

There are conditions, albeit somewhat unlikely, under which right hand
expressions, calculating the end of time period in functions like
repaper_frame_fixed_repeat(), may overflow.

For instance, if 'factor10x' in repaper_get_temperature() is high
enough (170), as is 'epd->stage_time' in repaper_probe(), then the
resulting value of 'end' will not fit in unsigned int expression.

Mitigate this by casting 'epd->factored_stage_time' to wider type before
any multiplication is done.

Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.

Fixes: 3589211e9b03 ("drm/tinydrm: Add RePaper e-ink driver")
Cc: stable@vger.kernel.org
Signed-off-by: Nikita Zhandarovich 
Signed-off-by: Alex Lanzano 
Link: https://patchwork.freedesktop.org/patch/msgid/20250116134801.22067-1-n.zhandarovich@fintech.ru
Signed-off-by: Greg Kroah-Hartman

drm/tiny/repaper: Use fbdev-dma

2024-05-02T09:33:31+00:00

Implement fbdev emulation with fbdev-dma. Fbdev-dma now supports
damage handling, which is required by repaper. Avoids the overhead of
fbdev-generic's additional shadow buffering. No functional changes.

Signed-off-by: Thomas Zimmermann 
Cc: "Noralf Trønnes" 
Acked-by: Noralf Trønnes 
Link: https://patchwork.freedesktop.org/patch/msgid/20240419083331.7761-40-tzimmermann@suse.de

drm/format-helper: Pass format-conversion state to helpers

2023-11-14T09:16:53+00:00

Pass an instance of struct drm_format_conv_state to DRM's format
conversion helpers. Update all callers.

Most drivers can use the format-conversion state from their shadow-
plane state. The shadow plane's destroy function releases the
allocated buffer. Drivers will later be able to allocate a buffer
of appropriate size in their plane's atomic_check code.

The gud driver uses a separate thread for committing updates. For
now, the update worker contains its own format-conversion state.

Images in the format-helper tests are small. The tests preallocate
a static page for the temporary buffer. Unloading the module releases
the memory.

v6:
	* update patch for ssd132x support
v5:
	* avoid using unusupported shadow-plane state in repaper (Noralf)
	* fix documentation (Noralf, kernel test robot)
v3:
	* store buffer in shadow-plane state (Javier, Maxime)
	* replace ARRAY_SIZE() with sizeof() (Jani)

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Tested-by: Javier Martinez Canillas  # ssd130x
Cc: Noralf Trønnes 
Cc: Javier Martinez Canillas 
Cc: Gerd Hoffmann 
Cc: David Lechner 
Link: https://patchwork.freedesktop.org/patch/msgid/20231009141018.11291-4-tzimmermann@suse.de

drm/repaper: fix -Wvoid-pointer-to-enum-cast warning

2023-08-25T11:13:20+00:00

When building with clang 18 I see the following warning:
|       drivers/gpu/drm/tiny/repaper.c:952:11: warning: cast to smaller integer
|       type 'enum repaper_model' from 'const void *' [-Wvoid-pointer-to-enum-cast]
|         952 |                 model = (enum repaper_model)match;
|

This is due to the fact that `match` is a void* while `enum repaper_model`
has the size of an int.

Add uintptr_t cast to silence clang warning while also keeping enum cast
for readability and consistency with other `model` assignment just a
few lines below:
|       model = (enum repaper_model)spi_id->driver_data;

Link: https://github.com/ClangBuiltLinux/linux/issues/1910
Reported-by: Nathan Chancellor 
Signed-off-by: Justin Stitt 
Signed-off-by: Noralf Trønnes 
Link: https://patchwork.freedesktop.org/patch/msgid/20230816-void-drivers-gpu-drm-tiny-repaper-v1-1-9d8d10f0d52f@google.com

drm/repaper: Reduce temporary buffer size in repaper_fb_dirty()

2023-07-29T19:22:02+00:00

As the temporary buffer is no longer used to store 8-bit grayscale data,
its size can be reduced to the size needed to store the monochrome
bitmap data.

Fixes: 24c6bedefbe71de9 ("drm/repaper: Use format helper for xrgb8888 to monochrome conversion")
Signed-off-by: Geert Uytterhoeven 
Reviewed-by: Javier Martinez Canillas 
Signed-off-by: Javier Martinez Canillas 
Link: https://patchwork.freedesktop.org/patch/msgid/20220317081830.1211400-6-geert@linux-m68k.org

drm/fb-helper: Move generic fbdev emulation into separate source file

2022-11-05T16:12:04+00:00

Move the generic fbdev implementation into its own source and header
file. Adapt drivers. No functional changes, but some of the internal
helpers have been renamed to fit into the drm_fbdev_ naming scheme.

v3:
	* rename drm_fbdev.{c,h} to drm_fbdev_generic.{c,h}
	* rebase onto vmwgfx changes
	* rebase onto xlnx changes
	* fix include statements in amdgpu

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Link: https://patchwork.freedesktop.org/patch/msgid/20221103151446.2638-22-tzimmermann@suse.de

drm/probe-helper: Add drm_crtc_helper_mode_valid_fixed()

2022-09-12T07:14:26+00:00

Add drm_crtc_helper_mode_valid_fixed(), which validates a given mode
against a display hardware's mode. Convert simpledrm and use it in a
few other drivers with static modes.

v4:
	* remove empty line after opening brace
v2:
	* rename 'static' and 'hw' to 'fixed' everywhere

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Sam Ravnborg 
Link: https://patchwork.freedesktop.org/patch/msgid/20220905141648.22013-3-tzimmermann@suse.de

drm/probe-helper: Add drm_connector_helper_get_modes_fixed()

2022-09-12T07:13:25+00:00

Add drm_connector_helper_get_modes_fixed(), which duplicates a single
display mode for a connector. Convert drivers.

v2:
	* rename 'static' and 'hw' to 'fixed' everywhere
	* fix typo 'there' to 'their' (Sam)

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Sam Ravnborg 
Link: https://patchwork.freedesktop.org/patch/msgid/20220905141648.22013-2-tzimmermann@suse.de

drm/format-helper: Rework XRGB8888-to-MONO conversion

2022-08-10T07:18:53+00:00

Update XRGB8888-to-MONO conversion to support struct iosys_map
and convert all users. Although these are single-plane color formats,
the new interface supports multi-plane formats for consistency with
drm_fb_blit().

v2:
	* rebase after renaming CMA helpers to DMA helpers
	* update documentation (Sam)

Signed-off-by: Thomas Zimmermann 
Tested-by: Noralf Trønnes 
Reviewed-by: Sam Ravnborg 
Link: https://patchwork.freedesktop.org/patch/msgid/20220808125406.20752-13-tzimmermann@suse.de

drm/gem: rename GEM CMA helpers to GEM DMA helpers

2022-08-03T16:31:49+00:00

Rename "GEM CMA" helpers to "GEM DMA" helpers - considering the
hierarchy of APIs (mm/cma -> dma -> gem dma) calling them "GEM
DMA" seems to be more applicable.

Besides that, commit e57924d4ae80 ("drm/doc: Task to rename CMA helpers")
requests to rename the CMA helpers and implies that people seem to be
confused about the naming.

In order to do this renaming the following script was used:

```
	#!/bin/bash

	DIRS="drivers/gpu include/drm Documentation/gpu"

	REGEX_SYM_UPPER="[0-9A-Z_\-]"
	REGEX_SYM_LOWER="[0-9a-z_\-]"

	REGEX_GREP_UPPER="(${REGEX_SYM_UPPER}*)(GEM)_CMA_(${REGEX_SYM_UPPER}*)"
	REGEX_GREP_LOWER="(${REGEX_SYM_LOWER}*)(gem)_cma_(${REGEX_SYM_LOWER}*)"

	REGEX_SED_UPPER="s/${REGEX_GREP_UPPER}/\1\2_DMA_\3/g"
	REGEX_SED_LOWER="s/${REGEX_GREP_LOWER}/\1\2_dma_\3/g"

	# Find all upper case 'CMA' symbols and replace them with 'DMA'.
	for ff in $(grep -REHl "${REGEX_GREP_UPPER}" $DIRS)
	do
	       sed -i -E "$REGEX_SED_UPPER" $ff
	done

	# Find all lower case 'cma' symbols and replace them with 'dma'.
	for ff in $(grep -REHl "${REGEX_GREP_LOWER}" $DIRS)
	do
	       sed -i -E "$REGEX_SED_LOWER" $ff
	done

	# Replace all occurrences of 'CMA' / 'cma' in comments and
	# documentation files with 'DMA' / 'dma'.
	for ff in $(grep -RiHl " cma " $DIRS)
	do
		sed -i -E "s/ cma / dma /g" $ff
		sed -i -E "s/ CMA / DMA /g" $ff
	done

	# Rename all 'cma_obj's to 'dma_obj'.
	for ff in $(grep -RiHl "cma_obj" $DIRS)
	do
		sed -i -E "s/cma_obj/dma_obj/g" $ff
	done
```

Only a few more manual modifications were needed, e.g. reverting the
following modifications in some DRM Kconfig files

    -       select CMA if HAVE_DMA_CONTIGUOUS
    +       select DMA if HAVE_DMA_CONTIGUOUS

as well as manually picking the occurrences of 'CMA'/'cma' in comments and
documentation which relate to "GEM CMA", but not "FB CMA".

Also drivers/gpu/drm/Makefile was fixed up manually after renaming
drm_gem_cma_helper.c to drm_gem_dma_helper.c.

This patch is compile-time tested building a x86_64 kernel with
`make allyesconfig && make drivers/gpu/drm`.

Acked-by: Sam Ravnborg 
Acked-by: Thomas Zimmermann 
Reviewed-by: Laurent Pinchart 
Signed-off-by: Danilo Krummrich 
Reviewed-by: Liviu Dudau  #drivers/gpu/drm/arm
Signed-off-by: Sam Ravnborg 
Link: https://patchwork.freedesktop.org/patch/msgid/20220802000405.949236-4-dakr@redhat.com