[PATCH V3 04/22] LoongArch: Add writecombine support for drm
From: Huacai Chen <hidden>
Date: 2021-09-17 04:01:01
Also in:
linux-arch, lkml
Subsystem:
drm drivers, drm drivers and misc gpu patches, drm ttm subsystem, the rest · Maintainers:
David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Christian Koenig, Huang Rui, Linus Torvalds
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. Signed-off-by: Huacai Chen <redacted> --- drivers/gpu/drm/drm_vm.c | 2 +- drivers/gpu/drm/ttm/ttm_module.c | 2 +- include/drm/drm_cache.h | 8 ++++++++ 3 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_vm.c b/drivers/gpu/drm/drm_vm.c
index e957d4851dc0..f024dc93939e 100644
--- a/drivers/gpu/drm/drm_vm.c
+++ b/drivers/gpu/drm/drm_vm.c@@ -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
diff --git a/drivers/gpu/drm/ttm/ttm_module.c b/drivers/gpu/drm/ttm/ttm_module.c
index 7fcdef278c74..3dc43390e76b 100644
--- a/drivers/gpu/drm/ttm/ttm_module.c
+++ b/drivers/gpu/drm/ttm/ttm_module.c@@ -60,7 +60,7 @@ pgprot_t ttm_prot_from_caching(enum ttm_caching caching, pgprot_t tmp) tmp = pgprot_noncached(tmp); #endif #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
diff --git a/include/drm/drm_cache.h b/include/drm/drm_cache.h
index cc9de1632dd3..5c1059435369 100644
--- a/include/drm/drm_cache.h
+++ b/include/drm/drm_cache.h@@ -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
--
2.27.0