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authorRussell King <rmk+kernel@arm.linux.org.uk>2011-07-08 21:26:59 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-07-12 11:08:12 +0100
commit022ae537b23cb14a391565e9ad9e9945f4b17138 (patch)
treee167c03036fcc09d7131fa364efa70c9e3d5b92a /arch/arm/mm
parent3973c337759cd201773a0ecc7b6f39f1ea2a6287 (diff)
downloadlinux-022ae537b23cb14a391565e9ad9e9945f4b17138.tar.gz
ARM: dma: replace ISA_DMA_THRESHOLD with a variable
ISA_DMA_THRESHOLD has been unused by non-arch code, so lets now get rid of it from ARM by replacing it with arm_dma_zone_mask. Move dma_supported() and dma_set_mask() out of line, and have dma_supported() check this new variable instead. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mm')
-rw-r--r--arch/arm/mm/dma-mapping.c35
-rw-r--r--arch/arm/mm/init.c10
-rw-r--r--arch/arm/mm/mm.h6
3 files changed, 48 insertions, 3 deletions
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 82a093cee09..0a0a1e7c20d 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -25,9 +25,11 @@
#include <asm/tlbflush.h>
#include <asm/sizes.h>
+#include "mm.h"
+
static u64 get_coherent_dma_mask(struct device *dev)
{
- u64 mask = ISA_DMA_THRESHOLD;
+ u64 mask = (u64)arm_dma_limit;
if (dev) {
mask = dev->coherent_dma_mask;
@@ -41,10 +43,10 @@ static u64 get_coherent_dma_mask(struct device *dev)
return 0;
}
- if ((~mask) & ISA_DMA_THRESHOLD) {
+ if ((~mask) & (u64)arm_dma_limit) {
dev_warn(dev, "coherent DMA mask %#llx is smaller "
"than system GFP_DMA mask %#llx\n",
- mask, (unsigned long long)ISA_DMA_THRESHOLD);
+ mask, (u64)arm_dma_limit);
return 0;
}
}
@@ -657,6 +659,33 @@ void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
}
EXPORT_SYMBOL(dma_sync_sg_for_device);
+/*
+ * Return whether the given device DMA address mask can be supported
+ * properly. For example, if your device can only drive the low 24-bits
+ * during bus mastering, then you would pass 0x00ffffff as the mask
+ * to this function.
+ */
+int dma_supported(struct device *dev, u64 mask)
+{
+ if (mask < (u64)arm_dma_limit)
+ return 0;
+ return 1;
+}
+EXPORT_SYMBOL(dma_supported);
+
+int dma_set_mask(struct device *dev, u64 dma_mask)
+{
+ if (!dev->dma_mask || !dma_supported(dev, dma_mask))
+ return -EIO;
+
+#ifndef CONFIG_DMABOUNCE
+ *dev->dma_mask = dma_mask;
+#endif
+
+ return 0;
+}
+EXPORT_SYMBOL(dma_set_mask);
+
#define PREALLOC_DMA_DEBUG_ENTRIES 4096
static int __init dma_debug_do_init(void)
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index c19571c40a2..17d6cd0c57e 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -212,6 +212,14 @@ static void __init arm_bootmem_init(unsigned long start_pfn,
}
#ifdef CONFIG_ZONE_DMA
+/*
+ * The DMA mask corresponding to the maximum bus address allocatable
+ * using GFP_DMA. The default here places no restriction on DMA
+ * allocations. This must be the smallest DMA mask in the system,
+ * so a successful GFP_DMA allocation will always satisfy this.
+ */
+u32 arm_dma_limit;
+
static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
unsigned long dma_size)
{
@@ -278,6 +286,8 @@ static void __init arm_bootmem_free(unsigned long min, unsigned long max_low,
*/
arm_adjust_dma_zone(zone_size, zhole_size,
ARM_DMA_ZONE_SIZE >> PAGE_SHIFT);
+
+ arm_dma_limit = PHYS_OFFSET + ARM_DMA_ZONE_SIZE - 1;
#endif
free_area_init_node(0, zone_size, min, zhole_size);
diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
index 5b3d7d54365..010566799c8 100644
--- a/arch/arm/mm/mm.h
+++ b/arch/arm/mm/mm.h
@@ -23,5 +23,11 @@ extern void __flush_dcache_page(struct address_space *mapping, struct page *page
#endif
+#ifdef CONFIG_ZONE_DMA
+extern u32 arm_dma_limit;
+#else
+#define arm_dma_limit ((u32)~0)
+#endif
+
void __init bootmem_init(void);
void arm_mm_memblock_reserve(void);