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x86, swiotlb: Simplify SWIOTLB pci_swiotlb_detect routine.

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In 'pci_swiotlb_detect' we used to do two different things:
 a). If user provided 'iommu=soft' or 'swiotlb=force' we
     would set swiotlb=1 and return 1 (and forcing pci-dma.c
     to call pci_swiotlb_init() immediately).
 b). If 4GB or more would be detected and if user did not specify
     iommu=off, we would set 'swiotlb=1' and return whatever 'a)'
     figured out.

We simplify this by splitting a) and b) in two different routines.

CC: Fujita Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
LKML-Reference: <1282845485-8991-5-git-send-email-konrad.wilk@oracle.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Konrad Rzeszutek Wilk
2010-08-26 13:57:59 -04:00
committed by H. Peter Anvin
parent 5bef80a4b8
commit efa631c26d
4 changed files with 43 additions and 11 deletions
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33
arch/x86/kernel/pci-swiotlb.c
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@@ -41,24 +41,33 @@ static struct dma_map_ops swiotlb_dma_ops = {
};
/*
* pci_swiotlb_detect - set swiotlb to 1 if necessary
* pci_swiotlb_detect_override - set swiotlb to 1 if necessary
*
* This returns non-zero if we are forced to use swiotlb (by the boot
* option).
*/
int __init pci_swiotlb_detect(void)
int __init pci_swiotlb_detect_override(void)
{
int use_swiotlb = swiotlb | swiotlb_force;
if (swiotlb_force)
swiotlb = 1;
return use_swiotlb;
}
/*
* if 4GB or more detected (and iommu=off not set) return 1
* and set swiotlb to 1.
*/
int __init pci_swiotlb_detect_4gb(void)
{
/* don't initialize swiotlb if iommu=off (no_iommu=1) */
#ifdef CONFIG_X86_64
if (!no_iommu && max_pfn > MAX_DMA32_PFN)
swiotlb = 1;
#endif
if (swiotlb_force)
swiotlb = 1;
return use_swiotlb;
return swiotlb;
}
void __init pci_swiotlb_init(void)
@@ -68,3 +77,15 @@ void __init pci_swiotlb_init(void)
dma_ops = &swiotlb_dma_ops;
}
}
void __init pci_swiotlb_late_init(void)
{
/* An IOMMU turned us off. */
if (!swiotlb)
swiotlb_free();
else {
printk(KERN_INFO "PCI-DMA: "
"Using software bounce buffering for IO (SWIOTLB)\n");
swiotlb_print_info();
}
}