1 files changed, 41 insertions, 3 deletions

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 82a093cee09..9cd5334019e 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -25,9 +25,11 @@
 #include <asm/tlbflush.h>
 #include <asm/sizes.h>
 
+#include "mm.h"
+
 static u64 get_coherent_dma_mask(struct device *dev)
 {
-        u64 mask = ISA_DMA_THRESHOLD;
+        u64 mask = (u64)arm_dma_limit;
 
         if (dev) {
                 mask = dev->coherent_dma_mask;
@@ -41,10 +43,10 @@ static u64 get_coherent_dma_mask(struct device *dev)
                         return 0;
                 }
 
-                if ((~mask) & ISA_DMA_THRESHOLD) {
+                if ((~mask) & (u64)arm_dma_limit) {
                         dev_warn(dev, "coherent DMA mask %#llx is smaller "
                                  "than system GFP_DMA mask %#llx\n",
-                                 mask, (unsigned long long)ISA_DMA_THRESHOLD);
+                                 mask, (u64)arm_dma_limit);
                         return 0;
                 }
         }
@@ -308,6 +310,13 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
         struct page *page;
         void *addr;
 
+        /* Following is a work-around (a.k.a. hack) to prevent pages
+         * with __GFP_COMP being passed to split_page() which cannot
+         * handle them.  The real problem is that this flag probably
+         * should be 0 on ARM as it is not supported on this
+         * platform--see CONFIG_HUGETLB_PAGE. */
+        gfp &= ~(__GFP_COMP);
+
         *handle = ~0;
         size = PAGE_ALIGN(size);
 
@@ -322,6 +331,8 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
 
         if (addr)
                 *handle = pfn_to_dma(dev, page_to_pfn(page));
+        else
+                __dma_free_buffer(page, size);
 
         return addr;
 }
@@ -657,6 +668,33 @@ void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 }
 EXPORT_SYMBOL(dma_sync_sg_for_device);
 
+/*
+ * Return whether the given device DMA address mask can be supported
+ * properly.  For example, if your device can only drive the low 24-bits
+ * during bus mastering, then you would pass 0x00ffffff as the mask
+ * to this function.
+ */
+int dma_supported(struct device *dev, u64 mask)
+{
+        if (mask < (u64)arm_dma_limit)
+                return 0;
+        return 1;
+}
+EXPORT_SYMBOL(dma_supported);
+
+int dma_set_mask(struct device *dev, u64 dma_mask)
+{
+        if (!dev->dma_mask || !dma_supported(dev, dma_mask))
+                return -EIO;
+
+#ifndef CONFIG_DMABOUNCE
+        *dev->dma_mask = dma_mask;
+#endif
+
+        return 0;
+}
+EXPORT_SYMBOL(dma_set_mask);
+
 #define PREALLOC_DMA_DEBUG_ENTRIES      4096
 
 static int __init dma_debug_do_init(void)