drm/ttm: remove ttm_bo_default_io_mem_pfn

No one will use this function except ttm_bo_io_mem_pfn() now, so move
the calculation of ttm_bo_default_io_mem_pfn() into ttm_bo_io_mem_pfn()
and do some cleanup.
Signed-off-by: Tan Xiaojun <tanxiaojun@huawei.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/ttm/ttm_bo_vm.c

@@ -100,7 +100,8 @@ static unsigned long ttm_bo_io_mem_pfn(struct ttm_buffer_object *bo,
 	if (bdev->driver->io_mem_pfn)
 		return bdev->driver->io_mem_pfn(bo, page_offset);
 
-	return ttm_bo_default_io_mem_pfn(bo, page_offset);
+	return ((bo->mem.bus.base + bo->mem.bus.offset) >> PAGE_SHIFT)
+		+ page_offset;
 }
 
 static int ttm_bo_vm_fault(struct vm_fault *vmf)
@@ -420,14 +421,6 @@ static struct ttm_buffer_object *ttm_bo_vm_lookup(struct ttm_bo_device *bdev,
 	return bo;
 }
 
-unsigned long ttm_bo_default_io_mem_pfn(struct ttm_buffer_object *bo,
-					unsigned long page_offset)
-{
-	return ((bo->mem.bus.base + bo->mem.bus.offset) >> PAGE_SHIFT)
-		+ page_offset;
-}
-EXPORT_SYMBOL(ttm_bo_default_io_mem_pfn);
-
 int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
 		struct ttm_bo_device *bdev)
 {

include/drm/ttm/ttm_bo_api.h

@@ -704,17 +704,6 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
  */
 int ttm_fbdev_mmap(struct vm_area_struct *vma, struct ttm_buffer_object *bo);
 
-/**
- * ttm_bo_default_iomem_pfn - get a pfn for a page offset
- *
- * @bo: the BO we need to look up the pfn for
- * @page_offset: offset inside the BO to look up.
- *
- * Calculate the PFN for iomem based mappings during page fault
- */
-unsigned long ttm_bo_default_io_mem_pfn(struct ttm_buffer_object *bo,
-				        unsigned long page_offset);
-
 /**
  * ttm_bo_mmap - mmap out of the ttm device address space.
  *