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Subject[RESEND2 PATCH 2/3] drivers: dma-coherent: use MEMREMAP_WC for DMA_MEMORY_MAP
Date
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@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Michal Nazarewicz <mina86@mina86.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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