common: dma-mapping: introduce common remapping functions

For architectures without coherent DMA, memory for DMA may need to be
remapped with coherent attributes.  Factor out the the remapping code from
arm and put it in a common location to reduce code duplication.

As part of this, the arm APIs are now migrated away from
ioremap_page_range to the common APIs which use map_vm_area for remapping.
 This should be an equivalent change and using map_vm_area is more correct
as ioremap_page_range is intended to bring in io addresses into the cpu
space and not regular kernel managed memory.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Riley <davidriley@chromium.org>
Cc: Olof Johansson <olof@lixom.net>
Cc: Ritesh Harjain <ritesh.harjani@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Mitchel Humpherys <mitchelh@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 9 insertions, 48 deletions

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 7a996aaa061e..eecc8e60deea 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -298,37 +298,19 @@ static void *
 __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,
         const void *caller)
 {
-        struct vm_struct *area;
-        unsigned long addr;
-
         /*
          * DMA allocation can be mapped to user space, so lets
          * set VM_USERMAP flags too.
          */
-        area = get_vm_area_caller(size, VM_ARM_DMA_CONSISTENT | VM_USERMAP,
-                                  caller);
-        if (!area)
-                return NULL;
-        addr = (unsigned long)area->addr;
-        area->phys_addr = __pfn_to_phys(page_to_pfn(page));
-
-        if (ioremap_page_range(addr, addr + size, area->phys_addr, prot)) {
-                vunmap((void *)addr);
-                return NULL;
-        }
-        return (void *)addr;
+        return dma_common_contiguous_remap(page, size,
+                        VM_ARM_DMA_CONSISTENT | VM_USERMAP,
+                        prot, caller);
 }
 
 static void __dma_free_remap(void *cpu_addr, size_t size)
 {
-        unsigned int flags = VM_ARM_DMA_CONSISTENT | VM_USERMAP;
-        struct vm_struct *area = find_vm_area(cpu_addr);
-        if (!area || (area->flags & flags) != 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);
+        dma_common_free_remap(cpu_addr, size,
+                        VM_ARM_DMA_CONSISTENT | VM_USERMAP);
 }
 
 #define DEFAULT_DMA_COHERENT_POOL_SIZE  SZ_256K
@@ -1271,29 +1253,8 @@ static void *
 __iommu_alloc_remap(struct page **pages, size_t size, gfp_t gfp, pgprot_t prot,
                     const void *caller)
 {
-        unsigned int i, nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
-        struct vm_struct *area;
-        unsigned long p;
-
-        area = get_vm_area_caller(size, VM_ARM_DMA_CONSISTENT | VM_USERMAP,
-                                  caller);
-        if (!area)
-                return NULL;
-
-        area->pages = pages;
-        area->nr_pages = nr_pages;
-        p = (unsigned long)area->addr;
-
-        for (i = 0; i < nr_pages; i++) {
-                phys_addr_t phys = __pfn_to_phys(page_to_pfn(pages[i]));
-                if (ioremap_page_range(p, p + PAGE_SIZE, phys, prot))
-                        goto err;
-                p += PAGE_SIZE;
-        }
-        return area->addr;
-err:
-        unmap_kernel_range((unsigned long)area->addr, size);
-        vunmap(area->addr);
+        return dma_common_pages_remap(pages, size,
+                        VM_ARM_DMA_CONSISTENT | VM_USERMAP, prot, caller);
         return NULL;
 }
 
@@ -1501,8 +1462,8 @@ void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
         }
 
         if (!dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, attrs)) {
-                unmap_kernel_range((unsigned long)cpu_addr, size);
-                vunmap(cpu_addr);
+                dma_common_free_remap(cpu_addr, size,
+                        VM_ARM_DMA_CONSISTENT | VM_USERMAP);
         }
 
         __iommu_remove_mapping(dev, handle, size);