powerpc/dma: pci_set_dma_mask() shouldn't fail if mask fits in RAM

On an iMac G5, the b43 driver is failing to initialise because trying to
set the dma mask to 30-bit fails. Even though there's only 512MiB of RAM
in the machine anyway:
	https://bugzilla.redhat.com/show_bug.cgi?id=514787

We should probably let it succeed if the available RAM in the system
doesn't exceed the requested limit.
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent f4b9a988
...@@ -7,6 +7,7 @@ ...@@ -7,6 +7,7 @@
#include <linux/device.h> #include <linux/device.h>
#include <linux/dma-mapping.h> #include <linux/dma-mapping.h>
#include <linux/lmb.h>
#include <asm/bug.h> #include <asm/bug.h>
#include <asm/abs_addr.h> #include <asm/abs_addr.h>
...@@ -90,11 +91,10 @@ static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg, ...@@ -90,11 +91,10 @@ static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
static int dma_direct_dma_supported(struct device *dev, u64 mask) static int dma_direct_dma_supported(struct device *dev, u64 mask)
{ {
#ifdef CONFIG_PPC64 #ifdef CONFIG_PPC64
/* Could be improved to check for memory though it better be /* Could be improved so platforms can set the limit in case
* done via some global so platforms can set the limit in case
* they have limited DMA windows * they have limited DMA windows
*/ */
return mask >= DMA_BIT_MASK(32); return mask >= (lmb_end_of_DRAM() - 1);
#else #else
return 1; return 1;
#endif #endif
......
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