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x86: merge dma_supported

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The code for both arches are very similar, so this patch merge them.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Glauber Costa
2008-04-08 13:20:55 -03:00
committed by Ingo Molnar
parent bca5c09663
commit 8e0c379718
3 changed files with 45 additions and 67 deletions
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44
arch/x86/kernel/pci-dma.c
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@@ -14,6 +14,8 @@ EXPORT_SYMBOL(forbid_dac);
const struct dma_mapping_ops *dma_ops;
EXPORT_SYMBOL(dma_ops);
int iommu_sac_force __read_mostly = 0;
#ifdef CONFIG_IOMMU_DEBUG
int panic_on_overflow __read_mostly = 1;
int force_iommu __read_mostly = 1;
@@ -103,6 +105,48 @@ void __init pci_iommu_alloc(void)
}
#endif
int dma_supported(struct device *dev, u64 mask)
{
#ifdef CONFIG_PCI
if (mask > 0xffffffff && forbid_dac > 0) {
printk(KERN_INFO "PCI: Disallowing DAC for device %s\n",
dev->bus_id);
return 0;
}
#endif
if (dma_ops->dma_supported)
return dma_ops->dma_supported(dev, mask);
/* Copied from i386. Doesn't make much sense, because it will
only work for pci_alloc_coherent.
The caller just has to use GFP_DMA in this case. */
if (mask < DMA_24BIT_MASK)
return 0;
/* Tell the device to use SAC when IOMMU force is on. This
allows the driver to use cheaper accesses in some cases.
Problem with this is that if we overflow the IOMMU area and
return DAC as fallback address the device may not handle it
correctly.
As a special case some controllers have a 39bit address
mode that is as efficient as 32bit (aic79xx). Don't force
SAC for these. Assume all masks <= 40 bits are of this
type. Normally this doesn't make any difference, but gives
more gentle handling of IOMMU overflow. */
if (iommu_sac_force && (mask >= DMA_40BIT_MASK)) {
printk(KERN_INFO "%s: Force SAC with mask %Lx\n",
dev->bus_id, mask);
return 0;
}
return 1;
}
EXPORT_SYMBOL(dma_supported);
static int __init pci_iommu_init(void)
{
#ifdef CONFIG_CALGARY_IOMMU