[PATCH v3 2/7] drm/ttm: Add ttm_kmap_obj_to_dma_buf_map() for type conversion

[Thomas Zimmermann <tzimmermann@suse.de>]

The new helper ttm_kmap_obj_to_dma_buf() extracts address and location
from and instance of TTM's kmap_obj and initializes struct dma_buf_map
with these values. Helpful for TTM-based drivers.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 include/drm/ttm/ttm_bo_api.h | 24 ++++++++++++++++++++++++
 include/linux/dma-buf-map.h  | 20 ++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index c96a25d571c8..62d89f05a801 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -34,6 +34,7 @@
 #include <drm/drm_gem.h>
 #include <drm/drm_hashtab.h>
 #include <drm/drm_vma_manager.h>
+#include <linux/dma-buf-map.h>
 #include <linux/kref.h>
 #include <linux/list.h>
 #include <linux/wait.h>
@@ -486,6 +487,29 @@ static inline void *ttm_kmap_obj_virtual(struct ttm_bo_kmap_obj *map,
 	return map->virtual;
 }
 
+/**
+ * ttm_kmap_obj_to_dma_buf_map
+ *
+ * @kmap: A struct ttm_bo_kmap_obj returned from ttm_bo_kmap.
+ * @map: Returns the mapping as struct dma_buf_map
+ *
+ * Converts struct ttm_bo_kmap_obj to struct dma_buf_map. If the memory
+ * is not mapped, the returned mapping is initialized to NULL.
+ */
+static inline void ttm_kmap_obj_to_dma_buf_map(struct ttm_bo_kmap_obj *kmap,
+					       struct dma_buf_map *map)
+{
+	bool is_iomem;
+	void *vaddr = ttm_kmap_obj_virtual(kmap, &is_iomem);
+
+	if (!vaddr)
+		dma_buf_map_clear(map);
+	else if (is_iomem)
+		dma_buf_map_set_vaddr_iomem(map, (void __force __iomem *)vaddr);
+	else
+		dma_buf_map_set_vaddr(map, vaddr);
+}
+
 /**
  * ttm_bo_kmap
  *
diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
index fd1aba545fdf..2e8bbecb5091 100644
--- a/include/linux/dma-buf-map.h
+++ b/include/linux/dma-buf-map.h
@@ -45,6 +45,12 @@
  *
  *	dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
  *
+ * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
+ *
+ * .. code-block:: c
+ *
+ *	dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
+ *
  * Test if a mapping is valid with either dma_buf_map_is_set() or
  * dma_buf_map_is_null().
  *
@@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct dma_buf_map *map, void *vaddr)
 	map->is_iomem = false;
 }
 
+/**
+ * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to an address in I/O memory
+ * @map:		The dma-buf mapping structure
+ * @vaddr_iomem:	An I/O-memory address
+ *
+ * Sets the address and the I/O-memory flag.
+ */
+static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
+					       void __iomem *vaddr_iomem)
+{
+	map->vaddr_iomem = vaddr_iomem;
+	map->is_iomem = true;
+}
+
 /**
  * dma_buf_map_is_equal - Compares two dma-buf mapping structures for equality
  * @lhs:	The dma-buf mapping structure
-- 
2.28.0