1 files changed, 72 insertions, 0 deletions

diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
index 6cd08e145bfa..9e8bbdd470ca 100644
--- a/drivers/base/dma-mapping.c
+++ b/drivers/base/dma-mapping.c
@@ -10,6 +10,8 @@
 #include <linux/dma-mapping.h>
 #include <linux/export.h>
 #include <linux/gfp.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
 #include <asm-generic/dma-coherent.h>
 
 /*
@@ -267,3 +269,73 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
         return ret;
 }
 EXPORT_SYMBOL(dma_common_mmap);
+
+#ifdef CONFIG_MMU
+/*
+ * remaps an array of PAGE_SIZE pages into another vm_area
+ * Cannot be used in non-sleeping contexts
+ */
+void *dma_common_pages_remap(struct page **pages, size_t size,
+                        unsigned long vm_flags, pgprot_t prot,
+                        const void *caller)
+{
+        struct vm_struct *area;
+
+        area = get_vm_area_caller(size, vm_flags, caller);
+        if (!area)
+                return NULL;
+
+        area->pages = pages;
+
+        if (map_vm_area(area, prot, pages)) {
+                vunmap(area->addr);
+                return NULL;
+        }
+
+        return area->addr;
+}
+
+/*
+ * remaps an allocated contiguous region into another vm_area.
+ * Cannot be used in non-sleeping contexts
+ */
+
+void *dma_common_contiguous_remap(struct page *page, size_t size,
+                        unsigned long vm_flags,
+                        pgprot_t prot, const void *caller)
+{
+        int i;
+        struct page **pages;
+        void *ptr;
+        unsigned long pfn;
+
+        pages = kmalloc(sizeof(struct page *) << get_order(size), GFP_KERNEL);
+        if (!pages)
+                return NULL;
+
+        for (i = 0, pfn = page_to_pfn(page); i < (size >> PAGE_SHIFT); i++)
+                pages[i] = pfn_to_page(pfn + i);
+
+        ptr = dma_common_pages_remap(pages, size, vm_flags, prot, caller);
+
+        kfree(pages);
+
+        return ptr;
+}
+
+/*
+ * unmaps a range previously mapped by dma_common_*_remap
+ */
+void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags)
+{
+        struct vm_struct *area = find_vm_area(cpu_addr);
+
+        if (!area || (area->flags & vm_flags) != vm_flags) {
+                WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
+                return;
+        }
+
+        unmap_kernel_range((unsigned long)cpu_addr, size);
+        vunmap(cpu_addr);
+}
+#endif