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

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 <sam@ravnborg.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Danilo Krummrich <dakr@redhat.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com> #drivers/gpu/drm/arm
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220802000405.949236-4-dakr@redhat.com

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/gpu/drm/armada/armada_gem.c b/drivers/gpu/drm/armada/armada_gem.c
index 147abf1a3968..5430265ad458 100644
--- a/drivers/gpu/drm/armada/armada_gem.c
+++ b/drivers/gpu/drm/armada/armada_gem.c
@@ -107,11 +107,11 @@ armada_gem_linear_back(struct drm_device *dev, struct armada_gem_object *obj)
 	}
 
 	/*
-	 * We could grab something from CMA if it's enabled, but that
+	 * We could grab something from DMA if it's enabled, but that
 	 * involves building in a problem:
 	 *
-	 * CMA's interface uses dma_alloc_coherent(), which provides us
-	 * with an CPU virtual address and a device address.
+	 * GEM DMA helper interface uses dma_alloc_coherent(), which provides
+	 * us with an CPU virtual address and a device address.
 	 *
 	 * The CPU virtual address may be either an address in the kernel
 	 * direct mapped region (for example, as it would be on x86) or