Commit 439057ec authored by Huacai Chen's avatar Huacai Chen
Browse files

LoongArch: Add writecombine support for drm 



LoongArch maintains cache coherency in hardware, but its WUC attribute
(Weak-ordered UnCached, which is similar to WC) is out of the scope of
cache coherency machanism. This means WUC can only used for write-only
memory regions.

Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: default avatarWANG Xuerui <git@xen0n.name>
Reviewed-by: default avatarJiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 08145b08

drivers/gpu/drm/drm_vm.c

+1 −1
Original line number Diff line number Diff line
@@ -69,7 +69,7 @@ static pgprot_t drm_io_prot(struct drm_local_map *map, 
	pgprot_t tmp = vm_get_page_prot(vma->vm_flags);



#if defined(__i386__) || defined(__x86_64__) || defined(__powerpc__) || \

    defined(__mips__)

    defined(__mips__) || defined(__loongarch__)

	if (map->type == _DRM_REGISTERS && !(map->flags & _DRM_WRITE_COMBINING))

		tmp = pgprot_noncached(tmp);

	else

drivers/gpu/drm/ttm/ttm_module.c

+1 −1
Original line number Diff line number Diff line
@@ -74,7 +74,7 @@ pgprot_t ttm_prot_from_caching(enum ttm_caching caching, pgprot_t tmp) 
#endif /* CONFIG_UML */

#endif /* __i386__ || __x86_64__ */

#if defined(__ia64__) || defined(__arm__) || defined(__aarch64__) || \

	defined(__powerpc__) || defined(__mips__)

	defined(__powerpc__) || defined(__mips__) || defined(__loongarch__)

	if (caching == ttm_write_combined)

		tmp = pgprot_writecombine(tmp);

	else

include/drm/drm_cache.h

+8 −0
Original line number Diff line number Diff line
@@ -67,6 +67,14 @@ static inline bool drm_arch_can_wc_memory(void) 
	 * optimization entirely for ARM and arm64.

	 */

	return false;

#elif defined(CONFIG_LOONGARCH)

	/*

	 * LoongArch maintains cache coherency in hardware, but its WUC attribute

	 * (Weak-ordered UnCached, which is similar to WC) is out of the scope of

	 * cache coherency machanism. This means WUC can only used for write-only

	 * memory regions.

	 */

	return false;

#else

	return true;

#endif