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Diffstat (limited to 'arch/x86/kernel/pci-swiotlb.c')
-rw-r--r--arch/x86/kernel/pci-swiotlb.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
index 17ce4221bd0..a6e5d0ffa3a 100644
--- a/arch/x86/kernel/pci-swiotlb.c
+++ b/arch/x86/kernel/pci-swiotlb.c
@@ -42,16 +42,27 @@ static struct dma_map_ops swiotlb_dma_ops = {
.dma_supported = NULL,
};
-void __init pci_swiotlb_init(void)
+/*
+ * pci_swiotlb_init - initialize swiotlb if necessary
+ *
+ * This returns non-zero if we are forced to use swiotlb (by the boot
+ * option).
+ */
+int __init pci_swiotlb_init(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;
+
if (swiotlb) {
swiotlb_init(0);
dma_ops = &swiotlb_dma_ops;
} else
dma_ops = &nommu_dma_ops;
+
+ return swiotlb_force;
}