drm/ttm: Clean usage of ttm_io_prot() with TTM_PL_FLAG_CACHED

Today, most callers of ttm_io_prot() check TTM_PL_FLAG_CACHED before
calling it since on some archs it will unconditionally create non-cached
mappings.

But not all callers do which is incorrect as far as I can tell.

Instead, move that check inside ttm_io_port() itself for all archs
and make powerpc use the same implementation as ia64 and arm

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

2 files changed, 9 insertions, 16 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 824af90cbe31..882cccdad272 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -480,28 +480,24 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
 
 pgprot_t ttm_io_prot(uint32_t caching_flags, pgprot_t tmp)
 {
+        /* Cached mappings need no adjustment */
+        if (caching_flags & TTM_PL_FLAG_CACHED)
+                return tmp;
+
 #if defined(__i386__) || defined(__x86_64__)
         if (caching_flags & TTM_PL_FLAG_WC)
                 tmp = pgprot_writecombine(tmp);
         else if (boot_cpu_data.x86 > 3)
                 tmp = pgprot_noncached(tmp);
-
-#elif defined(__powerpc__)
-        if (!(caching_flags & TTM_PL_FLAG_CACHED)) {
-                pgprot_val(tmp) |= _PAGE_NO_CACHE;
-                if (caching_flags & TTM_PL_FLAG_UNCACHED)
-                        pgprot_val(tmp) |= _PAGE_GUARDED;
-        }
 #endif
-#if defined(__ia64__) || defined(__arm__)
+#if defined(__ia64__) || defined(__arm__) || defined(__powerpc__)
         if (caching_flags & TTM_PL_FLAG_WC)
                 tmp = pgprot_writecombine(tmp);
         else
                 tmp = pgprot_noncached(tmp);
 #endif
 #if defined(__sparc__) || defined(__mips__)
-        if (!(caching_flags & TTM_PL_FLAG_CACHED))
-                tmp = pgprot_noncached(tmp);
+        tmp = pgprot_noncached(tmp);
 #endif
         return tmp;
 }
@@ -560,9 +556,7 @@ static int ttm_bo_kmap_ttm(struct ttm_buffer_object *bo,
                  * We need to use vmap to get the desired page protection
                  * or to make the buffer object look contiguous.
                  */
-                prot = (mem->placement & TTM_PL_FLAG_CACHED) ?
-                        PAGE_KERNEL :
-                        ttm_io_prot(mem->placement, PAGE_KERNEL);
+                prot = ttm_io_prot(mem->placement, PAGE_KERNEL);
                 map->bo_kmap_type = ttm_bo_map_vmap;
                 map->virtual = vmap(ttm->pages + start_page, num_pages,
                                     0, prot);
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index d05437f219e9..8fb7213277cc 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -197,9 +197,8 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
                                                 cvma.vm_page_prot);
         } else {
                 ttm = bo->ttm;
-                if (!(bo->mem.placement & TTM_PL_FLAG_CACHED))
-                        cvma.vm_page_prot = ttm_io_prot(bo->mem.placement,
-                                                        cvma.vm_page_prot);
+                cvma.vm_page_prot = ttm_io_prot(bo->mem.placement,
+                                                cvma.vm_page_prot);
 
                 /* Allocate all page at once, most common usage */
                 if (ttm->bdev->driver->ttm_tt_populate(ttm)) {