dma-mapping: make the get_required_mask method available unconditionally

This save some duplication for ia64, and makes the interface more
general.  In the long run we want each dma_map_ops instance to fill this
out, but this will take a little more prep work.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 11 insertions, 2 deletions

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index dff82a3c2caa..cfe22fded980 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -1179,8 +1179,7 @@ int __init platform_bus_init(void)
         return error;
 }
 
-#ifndef ARCH_HAS_DMA_GET_REQUIRED_MASK
-u64 dma_get_required_mask(struct device *dev)
+static u64 dma_default_get_required_mask(struct device *dev)
 {
         u32 low_totalram = ((max_pfn - 1) << PAGE_SHIFT);
         u32 high_totalram = ((max_pfn - 1) >> (32 - PAGE_SHIFT));
@@ -1198,6 +1197,16 @@ u64 dma_get_required_mask(struct device *dev)
         }
         return mask;
 }
+
+#ifndef ARCH_HAS_DMA_GET_REQUIRED_MASK
+u64 dma_get_required_mask(struct device *dev)
+{
+        const struct dma_map_ops *ops = get_dma_ops(dev);
+
+        if (ops->get_required_mask)
+                return ops->get_required_mask(dev);
+        return dma_default_get_required_mask(dev);
+}
 EXPORT_SYMBOL_GPL(dma_get_required_mask);
 #endif