[PATCH 22/28] x86: use a fallback dev for i386

Glauber Costa
2008-04-08T16:21:04Z

We can use a fallback dev for cases of a NULL device being passed (mostly ISA)
This comes from x86_64 implementation.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
---
arch/x86/kernel/pci-dma_32.c | 13 +++++++++++++
1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/pci-dma_32.c b/arch/x86/kernel/pci-dma_32.c
index f6cf434..0e9ec11 100644
--- a/arch/x86/kernel/pci-dma_32.c
+++ b/arch/x86/kernel/pci-dma_32.c
@@ -14,6 +14,16 @@
#include <linux/module.h>
#include <asm/io.h>

+/* Dummy device used for NULL arguments (normally ISA). Better would
+ be probably a smaller DMA mask, but this is bug-to-bug compatible
+ to i386. */
+struct device fallback_dev = {
+ .bus_id = "fallback device",
+ .coherent_dma_mask = DMA_32BIT_MASK,
+ .dma_mask = &fallback_dev.coherent_dma_mask,
+};
+
+
static int dma_alloc_from_coherent_mem(struct device *dev, ssize_t size,
dma_addr_t *dma_handle, void **ret)
{
@@ -77,6 +87,9 @@ void *dma_alloc_coherent(struct device *dev, size_t size,
if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
gfp |= GFP_DMA;

+ if (!dev)
+ dev = &fallback_dev;
+
dma_mask = dev->coherent_dma_mask;
if (dma_mask == 0)
dma_mask = DMA_32BIT_MASK;
--
1.5.0.6