The patch titled
Subject: drivers: dma-coherent: use MEMREMAP_WC for DMA_MEMORY_MAP
has been added to the -mm tree. Its filename is
drivers-dma-coherent-use-memremap_wc-for-dma_memory_map.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/drivers-dma-coherent-use-memremap_wc-for-dma_memory_map.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/drivers-dma-coherent-use-memremap_wc-for-dma_memory_map.patch
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------------------------------------------------------
From: Brian Starkey <brian.starkey@xxxxxxx>
Subject: drivers: dma-coherent: use MEMREMAP_WC for DMA_MEMORY_MAP
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.starkey@xxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/base/dma-coherent.c | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
diff -puN drivers/base/dma-coherent.c~drivers-dma-coherent-use-memremap_wc-for-dma_memory_map drivers/base/dma-coherent.c
--- a/drivers/base/dma-coherent.c~drivers-dma-coherent-use-memremap_wc-for-dma_memory_map
+++ a/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 bool dma_init_coherent_memory(
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;
@@ -54,8 +58,12 @@ static bool dma_init_coherent_memory(
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 false;
}
@@ -63,7 +71,11 @@ static void dma_release_coherent_memory(
{
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);
}
_
Patches currently in -mm which might be from brian.starkey@xxxxxxx are
memremap-dont-modify-flags.patch
memremap-add-memremap_wc-flag.patch
drivers-dma-coherent-use-memremap_wc-for-dma_memory_map.patch
drivers-dma-coherent-use-memset_io-for-dma_memory_io-mappings.patch
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