[RESEND PATCH 2/3] drivers: dma-coherent: use MEMREMAP_WC for DMA_MEMORY_MAP

[Brian Starkey]

When the DMA_MEMORY_MAP flag is used, memory which can be accessed
directly should be returned, so use memremap(..., MEMREMAP_WC) to
provide a writecombine mapping.

Signed-off-by: Brian Starkey <brian.star...@arm.com>
Reviewed-by: Catalin Marinas <catalin.mari...@arm.com>
---
 drivers/base/dma-coherent.c |   20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c
index 55b8398..f98359a 100644
--- a/drivers/base/dma-coherent.c
+++ b/drivers/base/dma-coherent.c
@@ -2,6 +2,7 @@
  * Coherent per-device memory handling.
  * Borrowed from i386
  */
+#include <linux/io.h>
 #include <linux/slab.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -31,7 +32,10 @@ static int dma_init_coherent_memory(phys_addr_t phys_addr, 
dma_addr_t device_add
        if (!size)
                goto out;
 
-       mem_base = ioremap(phys_addr, size);
+       if (flags & DMA_MEMORY_MAP)
+               mem_base = memremap(phys_addr, size, MEMREMAP_WC);
+       else
+               mem_base = ioremap(phys_addr, size);
        if (!mem_base)
                goto out;
 
@@ -58,8 +62,12 @@ static int dma_init_coherent_memory(phys_addr_t phys_addr, 
dma_addr_t device_add
 
 out:
        kfree(dma_mem);
-       if (mem_base)
-               iounmap(mem_base);
+       if (mem_base) {
+               if (flags & DMA_MEMORY_MAP)
+                       memunmap(mem_base);
+               else
+                       iounmap(mem_base);
+       }
        return 0;
 }
 
@@ -67,7 +75,11 @@ static void dma_release_coherent_memory(struct 
dma_coherent_mem *mem)
 {
        if (!mem)
                return;
-       iounmap(mem->virt_base);
+
+       if (mem->flags & DMA_MEMORY_MAP)
+               memunmap(mem->virt_base);
+       else
+               iounmap(mem->virt_base);
        kfree(mem->bitmap);
        kfree(mem);
 }
-- 
1.7.9.5

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