+static void
+nouveau_decode_mod(struct nouveau_drm *drm,
+ uint64_t modifier,
+ uint32_t *tile_mode,
+ uint8_t *kind)
+{
+ BUG_ON(!tile_mode || !kind);
+
+ if (modifier == DRM_FORMAT_MOD_LINEAR) {
+ /* tile_mode will not be used in this case */
+ *tile_mode = 0;
+ *kind = 0;
+ } else {
+ /*
+ * Extract the block height and kind from the corresponding
+ * modifier fields. See drm_fourcc.h for details.
+ */
+ *tile_mode = (uint32_t)(modifier & 0xF);
+ *kind = (uint8_t)((modifier >> 12) & 0xFF);
+
+ if (drm->client.device.info.chipset >= 0xc0)
+ *tile_mode <<= 4;
+ }
+}
+
+void
+nouveau_framebuffer_get_layout(struct drm_framebuffer *fb,
+ uint32_t *tile_mode,
+ uint8_t *kind)
+{
+ if (fb->flags & DRM_MODE_FB_MODIFIERS) {
+ struct nouveau_drm *drm = nouveau_drm(fb->dev);
+
+ nouveau_decode_mod(drm, fb->modifier, tile_mode, kind);
+ } else {
+ const struct nouveau_bo *nvbo = nouveau_gem_object(fb->obj[0]);
+
+ *tile_mode = nvbo->mode;
+ *kind = nvbo->kind;
+ }
+}
+
+static int
+nouveau_validate_decode_mod(struct nouveau_drm *drm,
+ uint64_t modifier,
+ uint32_t *tile_mode,
+ uint8_t *kind)
+{
+ struct nouveau_display *disp = nouveau_display(drm->dev);
+ int mod;
+
+ if (drm->client.device.info.family < NV_DEVICE_INFO_V0_TESLA) {
+ return -EINVAL;
+ }
+
+ BUG_ON(!disp->format_modifiers);
+
+ for (mod = 0;
+ (disp->format_modifiers[mod] != DRM_FORMAT_MOD_INVALID) &&
+ (disp->format_modifiers[mod] != modifier);
+ mod++);
+
+ if (disp->format_modifiers[mod] == DRM_FORMAT_MOD_INVALID)
+ return -EINVAL;
+
+ nouveau_decode_mod(drm, modifier, tile_mode, kind);
+
+ return 0;
+}
+