1 files changed, 44 insertions, 11 deletions

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 1272ed202dde..f61a5707823a 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -9,6 +9,7 @@
  *
  *  DMA uncached mapping support.
  */
+#include <linux/bootmem.h>
 #include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/gfp.h>
@@ -157,9 +158,47 @@ struct dma_map_ops arm_coherent_dma_ops = {
 };
 EXPORT_SYMBOL(arm_coherent_dma_ops);
 
+static int __dma_supported(struct device *dev, u64 mask, bool warn)
+{
+	unsigned long max_dma_pfn;
+
+	/*
+	 * If the mask allows for more memory than we can address,
+	 * and we actually have that much memory, then we must
+	 * indicate that DMA to this device is not supported.
+	 */
+	if (sizeof(mask) != sizeof(dma_addr_t) &&
+	    mask > (dma_addr_t)~0 &&
+	    dma_to_pfn(dev, ~0) < max_pfn) {
+		if (warn) {
+			dev_warn(dev, "Coherent DMA mask %#llx is larger than dma_addr_t allows\n",
+				 mask);
+			dev_warn(dev, "Driver did not use or check the return value from dma_set_coherent_mask()?\n");
+		}
+		return 0;
+	}
+
+	max_dma_pfn = min(max_pfn, arm_dma_pfn_limit);
+
+	/*
+	 * Translate the device's DMA mask to a PFN limit.  This
+	 * PFN number includes the page which we can DMA to.
+	 */
+	if (dma_to_pfn(dev, mask) < max_dma_pfn) {
+		if (warn)
+			dev_warn(dev, "Coherent DMA mask %#llx (pfn %#lx-%#lx) covers a smaller range of system memory than the DMA zone pfn 0x0-%#lx\n",
+				 mask,
+				 dma_to_pfn(dev, 0), dma_to_pfn(dev, mask) + 1,
+				 max_dma_pfn + 1);
+		return 0;
+	}
+
+	return 1;
+}
+
 static u64 get_coherent_dma_mask(struct device *dev)
 {
-	u64 mask = (u64)arm_dma_limit;
+	u64 mask = (u64)DMA_BIT_MASK(32);
 
 	if (dev) {
 		mask = dev->coherent_dma_mask;
@@ -173,12 +212,8 @@ static u64 get_coherent_dma_mask(struct device *dev)
 			return 0;
 		}
 
-		if ((~mask) & (u64)arm_dma_limit) {
-			dev_warn(dev, "coherent DMA mask %#llx is smaller "
-				 "than system GFP_DMA mask %#llx\n",
-				 mask, (u64)arm_dma_limit);
+		if (!__dma_supported(dev, mask, true))
 			return 0;
-		}
 	}
 
 	return mask;
@@ -687,7 +722,7 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
 void *arm_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
 		    gfp_t gfp, struct dma_attrs *attrs)
 {
-	pgprot_t prot = __get_dma_pgprot(attrs, pgprot_kernel);
+	pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL);
 	void *memory;
 
 	if (dma_alloc_from_coherent(dev, size, handle, &memory))
@@ -700,7 +735,7 @@ void *arm_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
 static void *arm_coherent_dma_alloc(struct device *dev, size_t size,
 	dma_addr_t *handle, gfp_t gfp, struct dma_attrs *attrs)
 {
-	pgprot_t prot = __get_dma_pgprot(attrs, pgprot_kernel);
+	pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL);
 	void *memory;
 
 	if (dma_alloc_from_coherent(dev, size, handle, &memory))
@@ -1007,9 +1042,7 @@ void arm_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
  */
 int dma_supported(struct device *dev, u64 mask)
 {
-	if (mask < (u64)arm_dma_limit)
-		return 0;
-	return 1;
+	return __dma_supported(dev, mask, false);
 }
 EXPORT_SYMBOL(dma_supported);