x86: isolate coherent mapping functions

i386 implements the declare coherent memory API, and x86_64 does not
it is reflected in pieces of dma_alloc_coherent and dma_free_coherent.
Those pieces are isolated in separate functions, that are declared
as empty macros in x86_64. This way we can make the code the same.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 10 insertions, 1 deletions

diff --git a/arch/x86/kernel/pci-dma_64.c b/arch/x86/kernel/pci-dma_64.c
index e7d45cf82251..6eacd58e451b 100644
--- a/arch/x86/kernel/pci-dma_64.c
+++ b/arch/x86/kernel/pci-dma_64.c
@@ -39,6 +39,8 @@ dma_alloc_pages(struct device *dev, gfp_t gfp, unsigned order)
         return page ? page_address(page) : NULL;
 }
 
+#define dma_alloc_from_coherent_mem(dev, size, handle, ret) (0)
+#define dma_release_coherent(dev, order, vaddr) (0)
 /*
  * Allocate memory for a coherent mapping.
  */
@@ -50,6 +52,10 @@ dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle,
         unsigned long dma_mask = 0;
         u64 bus;
 
+
+        if (dma_alloc_from_coherent_mem(dev, size, dma_handle, &memory))
+                return memory;
+
         if (!dev)
                 dev = &fallback_dev;
         dma_mask = dev->coherent_dma_mask;
@@ -141,9 +147,12 @@ EXPORT_SYMBOL(dma_alloc_coherent);
 void dma_free_coherent(struct device *dev, size_t size,
                          void *vaddr, dma_addr_t bus)
 {
+        int order = get_order(size);
         WARN_ON(irqs_disabled());       /* for portability */
+        if (dma_release_coherent(dev, order, vaddr))
+                return;
         if (dma_ops->unmap_single)
                 dma_ops->unmap_single(dev, bus, size, 0);
-        free_pages((unsigned long)vaddr, get_order(size));
+        free_pages((unsigned long)vaddr, order);
 }
 EXPORT_SYMBOL(dma_free_coherent);