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-rw-r--r--arch/x86/kernel/pci-dma.c4
-rw-r--r--arch/x86/kernel/pci-swiotlb.c33
2 files changed, 30 insertions, 7 deletions
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 9f07cfcbd3a5..1b3beb5075e6 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -133,9 +133,11 @@ void __init pci_iommu_alloc(void)
/* free the range so iommu could get some range less than 4G */
dma32_free_bootmem();
- if (pci_xen_swiotlb_detect() || pci_swiotlb_detect())
+ if (pci_xen_swiotlb_detect() || pci_swiotlb_detect_override())
goto out;
+ pci_swiotlb_detect_4gb();
+
gart_iommu_hole_init();
detect_calgary();
diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
index a5bc528d4328..c7a72faeb146 100644
--- a/arch/x86/kernel/pci-swiotlb.c
+++ b/arch/x86/kernel/pci-swiotlb.c
@@ -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();
+ }
+}