[PATCH 2/3] drm/ttm: add API to reserve/free WC memory.

[Dave Airlie]

From: Dave Airlie <airlied at redhat.com>

These will be used by drivers to reserve/free WC memory in the
PAT tracking tables, for VRAM BARs.

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 drivers/gpu/drm/ttm/ttm_bo_util.c | 24 ++++++++++++++++++++++++
 include/drm/ttm/ttm_bo_driver.h   |  2 ++
 2 files changed, 26 insertions(+)

diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index bf6e216..192c003 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -39,6 +39,13 @@
 #include <linux/module.h>
 #include <linux/reservation.h>
 
+#ifdef CONFIG_X86
+#include <asm/pat.h>
+#else
+#define io_reserve_memtype(start, end, pcm) (0)
+#define io_free_memtype(start, end)
+#endif
+
 void ttm_bo_free_old_node(struct ttm_buffer_object *bo)
 {
 	ttm_bo_mem_put(bo, &bo->mem);
@@ -796,3 +803,20 @@ int ttm_bo_pipeline_move(struct ttm_buffer_object *bo,
 	return 0;
 }
 EXPORT_SYMBOL(ttm_bo_pipeline_move);
+
+int ttm_io_reserve_memtype_wc(resource_size_t start, resource_size_t end)
+{
+	enum page_cache_mode pcm = _PAGE_CACHE_MODE_WC;
+	int ret;
+	ret = io_reserve_memtype(start, end, &pcm);
+	if (ret)
+		return ret;
+	return 0;
+}
+EXPORT_SYMBOL(ttm_io_reserve_memtype_wc);
+
+void ttm_io_free_memtype(resource_size_t start, resource_size_t end)
+{
+	io_free_memtype(start, end);
+}
+EXPORT_SYMBOL(ttm_io_free_memtype);
diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
index 4f0a921..6b2d24e 100644
--- a/include/drm/ttm/ttm_bo_driver.h
+++ b/include/drm/ttm/ttm_bo_driver.h
@@ -1054,6 +1054,8 @@ int ttm_bo_pipeline_move(struct ttm_buffer_object *bo,
  */
 extern pgprot_t ttm_io_prot(uint32_t caching_flags, pgprot_t tmp);
 
+int ttm_io_reserve_memtype_wc(resource_size_t start, resource_size_t end);
+void ttm_io_free_memtype(resource_size_t start, resource_size_t end);
 extern const struct ttm_mem_type_manager_func ttm_bo_manager_func;
 
 #if IS_ENABLED(CONFIG_AGP)
-- 
2.5.5