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>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index c19571c40a21..17d6cd0c57ed 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);