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ARM: another fix for the DMA mapping checks

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Peter reports that OMAP audio broke with the recent fix for these
checks, caused by OMAP audio using a 64-bit DMA mask.  We should
allow 64-bit DMA masks even with 32-bit dma_addr_t if we can be sure
the amount of RAM we have won't allow the 32-bit dma_addr_t to
overflow.  Unfortunately, the checks to detect overflow were not
correct.

Tested-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2013-12-06 12:30:42 +00:00
parent 11d4bb1bd0
commit 9f28cde0bc
1 changed files with 40 additions and 51 deletions
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91
arch/arm/mm/dma-mapping.c
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@ -158,13 +158,49 @@ struct dma_map_ops arm_coherent_dma_ops = {
};
EXPORT_SYMBOL(arm_coherent_dma_ops);
static int __dma_supported(struct device *dev, u64 mask, bool warn)
{
unsigned long max_dma_pfn;
/*
* If the mask allows for more memory than we can address,
* and we actually have that much memory, then we must
* indicate that DMA to this device is not supported.
*/
if (sizeof(mask) != sizeof(dma_addr_t) &&
mask > (dma_addr_t)~0 &&
dma_to_pfn(dev, ~0) < max_pfn) {
if (warn) {
dev_warn(dev, "Coherent DMA mask %#llx is larger than dma_addr_t allows\n",
mask);
dev_warn(dev, "Driver did not use or check the return value from dma_set_coherent_mask()?\n");
}
return 0;
}
max_dma_pfn = min(max_pfn, arm_dma_pfn_limit);
/*
* Translate the device's DMA mask to a PFN limit. This
* PFN number includes the page which we can DMA to.
*/
if (dma_to_pfn(dev, mask) < max_dma_pfn) {
if (warn)
dev_warn(dev, "Coherent DMA mask %#llx (pfn %#lx-%#lx) covers a smaller range of system memory than the DMA zone pfn 0x0-%#lx\n",
mask,
dma_to_pfn(dev, 0), dma_to_pfn(dev, mask) + 1,
max_dma_pfn + 1);
return 0;
}
return 1;
}
static u64 get_coherent_dma_mask(struct device *dev)
{
u64 mask = (u64)DMA_BIT_MASK(32);
if (dev) {
unsigned long max_dma_pfn;
mask = dev->coherent_dma_mask;
/*
@ -176,34 +212,8 @@ static u64 get_coherent_dma_mask(struct device *dev)
return 0;
}
max_dma_pfn = min(max_pfn, arm_dma_pfn_limit);
/*
* If the mask allows for more memory than we can address,
* and we actually have that much memory, then fail the
* allocation.
*/
if (sizeof(mask) != sizeof(dma_addr_t) &&
mask > (dma_addr_t)~0 &&
dma_to_pfn(dev, ~0) > max_dma_pfn) {
dev_warn(dev, "Coherent DMA mask %#llx is larger than dma_addr_t allows\n",
mask);
dev_warn(dev, "Driver did not use or check the return value from dma_set_coherent_mask()?\n");
if (!__dma_supported(dev, mask, true))
return 0;
}
/*
* Now check that the mask, when translated to a PFN,
* fits within the allowable addresses which we can
* allocate.
*/
if (dma_to_pfn(dev, mask) < max_dma_pfn) {
dev_warn(dev, "Coherent DMA mask %#llx (pfn %#lx-%#lx) covers a smaller range of system memory than the DMA zone pfn 0x0-%#lx\n",
mask,
dma_to_pfn(dev, 0), dma_to_pfn(dev, mask) + 1,
arm_dma_pfn_limit + 1);
return 0;
}
}
return mask;
@ -1032,28 +1042,7 @@ void arm_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
*/
int dma_supported(struct device *dev, u64 mask)
{
unsigned long limit;
/*
* If the mask allows for more memory than we can address,
* and we actually have that much memory, then we must
* indicate that DMA to this device is not supported.
*/
if (sizeof(mask) != sizeof(dma_addr_t) &&
mask > (dma_addr_t)~0 &&
dma_to_pfn(dev, ~0) > arm_dma_pfn_limit)
return 0;
/*
* Translate the device's DMA mask to a PFN limit. This
* PFN number includes the page which we can DMA to.
*/
limit = dma_to_pfn(dev, mask);
if (limit < arm_dma_pfn_limit)
return 0;
return 1;
return __dma_supported(dev, mask, false);
}
EXPORT_SYMBOL(dma_supported);