drm: Update drm_addmap and drm_mmap to use PAT WC instead of MTRRs

Previously, DRM_FRAME_BUFFER mappings, as well as DRM_REGISTERS
mappings with DRM_WRITE_COMBINING set, resulted in an unconditional
MTRR being added but the actual mappings being created as UC-.

Now these mappings have the MTRR added only if needed, but they will
be mapped with pgprot_writecombine.

The non-WC DRM_REGISTERS case now uses pgprot_noncached instead of
hardcoding the bit twiddling.

The DRM_AGP case is unchanged for now.

[airlied: fix ppc build]
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 9 insertions, 8 deletions

diff --git a/drivers/gpu/drm/drm_bufs.c b/drivers/gpu/drm/drm_bufs.c
index 0128147265f3..0190fce20078 100644
--- a/drivers/gpu/drm/drm_bufs.c
+++ b/drivers/gpu/drm/drm_bufs.c
@@ -210,12 +210,16 @@ static int drm_addmap_core(struct drm_device * dev, resource_size_t offset,
                 if (drm_core_has_MTRR(dev)) {
                         if (map->type == _DRM_FRAME_BUFFER ||
                             (map->flags & _DRM_WRITE_COMBINING)) {
-                                map->mtrr = mtrr_add(map->offset, map->size,
-                                                     MTRR_TYPE_WRCOMB, 1);
+                                map->mtrr =
+                                        arch_phys_wc_add(map->offset, map->size);
                         }
                 }
                 if (map->type == _DRM_REGISTERS) {
-                        map->handle = ioremap(map->offset, map->size);
+                        if (map->flags & _DRM_WRITE_COMBINING)
+                                map->handle = ioremap_wc(map->offset,
+                                                         map->size);
+                        else
+                                map->handle = ioremap(map->offset, map->size);
                         if (!map->handle) {
                                 kfree(map);
                                 return -ENOMEM;
@@ -451,11 +455,8 @@ int drm_rmmap_locked(struct drm_device *dev, struct drm_local_map *map)
                 iounmap(map->handle);
                 /* FALLTHROUGH */
         case _DRM_FRAME_BUFFER:
-                if (drm_core_has_MTRR(dev) && map->mtrr >= 0) {
-                        int retcode;
-                        retcode = mtrr_del(map->mtrr, map->offset, map->size);
-                        DRM_DEBUG("mtrr_del=%d\n", retcode);
-                }
+                if (drm_core_has_MTRR(dev))
+                        arch_phys_wc_del(map->mtrr);
                 break;
         case _DRM_SHM:
                 vfree(map->handle);