Michael Buesch wrote:
On Tuesday 08 July 2008 19:40:06 Steve Brown wrote:
There appears to be no function like pci_set_consistent_dma_mask to set
the coherent mask for a non-pci device.
What is the "proper" way to set it?
The context for the question is a recent change to ssb_dma_set_mask() in
drivers/ssb/main.c that removed the somewhat fragile, direct
manipulation of dma_mask and coherent_dma_mask in favor of a call to
dma_set_mask().
Note that SSB devices use the dma_*** API for doing DMA remappings.
So it uses dma_set_mask() for setting the mask.
I can't find any dma_*** routine that references coherent_dma_mask. It
looks like dma_set_mask() doesn't handle the case where the device
doesn't support coherent dma (CONFIG_DMA_NONCOHERENT=y).
Would this be the correct patch to handle that case?
Steve
diff --git a/include/asm-mips/dma-mapping.h b/include/asm-mips/dma-mapping.h
index 230b3f1..8da4107 100644
--- a/include/asm-mips/dma-mapping.h
+++ b/include/asm-mips/dma-mapping.h
@@ -1,8 +1,9 @@
#ifndef _ASM_DMA_MAPPING_H
#define _ASM_DMA_MAPPING_H
-#include <asm/scatterlist.h>
+#include <linux/scatterlist.h>
#include <asm/cache.h>
+#include <dma-coherence.h>
void *dma_alloc_noncoherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t flag);
@@ -48,7 +49,11 @@ extern int dma_supported(struct device *dev, u64 mask);
static inline int
dma_set_mask(struct device *dev, u64 mask)
{
- if(!dev->dma_mask || !dma_supported(dev, mask))
+ if(!dma_supported(dev, mask))
+ return -EIO;
+ if(!plat_device_is_coherent(dev))
+ dev->dma_mask = &dev->coherent_dma_mask;
+ if(!dev->dma_mask)
return -EIO;
*dev->dma_mask = mask;
