1 /* Glue code to lib/swiotlb.c */
2
3 #include <linux/pci.h>
4 #include <linux/cache.h>
5 #include <linux/module.h>
6 #include <linux/swiotlb.h>
7 #include <linux/bootmem.h>
8 #include <linux/dma-mapping.h>
9
10 #include <asm/iommu.h>
11 #include <asm/swiotlb.h>
12 #include <asm/dma.h>
13 #include <asm/xen/swiotlb-xen.h>
14 #include <asm/iommu_table.h>
15 int swiotlb __read_mostly;
16
x86_swiotlb_alloc_coherent(struct device * hwdev,size_t size,dma_addr_t * dma_handle,gfp_t flags)17 static void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
18 dma_addr_t *dma_handle, gfp_t flags)
19 {
20 void *vaddr;
21
22 vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags);
23 if (vaddr)
24 return vaddr;
25
26 return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
27 }
28
29 static struct dma_map_ops swiotlb_dma_ops = {
30 .mapping_error = swiotlb_dma_mapping_error,
31 .alloc_coherent = x86_swiotlb_alloc_coherent,
32 .free_coherent = swiotlb_free_coherent,
33 .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
34 .sync_single_for_device = swiotlb_sync_single_for_device,
35 .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
36 .sync_sg_for_device = swiotlb_sync_sg_for_device,
37 .map_sg = swiotlb_map_sg_attrs,
38 .unmap_sg = swiotlb_unmap_sg_attrs,
39 .map_page = swiotlb_map_page,
40 .unmap_page = swiotlb_unmap_page,
41 .dma_supported = NULL,
42 };
43
44 /*
45 * pci_swiotlb_detect_override - set swiotlb to 1 if necessary
46 *
47 * This returns non-zero if we are forced to use swiotlb (by the boot
48 * option).
49 */
pci_swiotlb_detect_override(void)50 int __init pci_swiotlb_detect_override(void)
51 {
52 int use_swiotlb = swiotlb | swiotlb_force;
53
54 if (swiotlb_force)
55 swiotlb = 1;
56
57 return use_swiotlb;
58 }
59 IOMMU_INIT_FINISH(pci_swiotlb_detect_override,
60 pci_xen_swiotlb_detect,
61 pci_swiotlb_init,
62 pci_swiotlb_late_init);
63
64 /*
65 * if 4GB or more detected (and iommu=off not set) return 1
66 * and set swiotlb to 1.
67 */
pci_swiotlb_detect_4gb(void)68 int __init pci_swiotlb_detect_4gb(void)
69 {
70 /* don't initialize swiotlb if iommu=off (no_iommu=1) */
71 #ifdef CONFIG_X86_64
72 if (!no_iommu && max_pfn > MAX_DMA32_PFN)
73 swiotlb = 1;
74 #endif
75 return swiotlb;
76 }
77 IOMMU_INIT(pci_swiotlb_detect_4gb,
78 pci_swiotlb_detect_override,
79 pci_swiotlb_init,
80 pci_swiotlb_late_init);
81
pci_swiotlb_init(void)82 void __init pci_swiotlb_init(void)
83 {
84 if (swiotlb) {
85 swiotlb_init(0);
86 dma_ops = &swiotlb_dma_ops;
87 }
88 }
89
pci_swiotlb_late_init(void)90 void __init pci_swiotlb_late_init(void)
91 {
92 /* An IOMMU turned us off. */
93 if (!swiotlb)
94 swiotlb_free();
95 else {
96 printk(KERN_INFO "PCI-DMA: "
97 "Using software bounce buffering for IO (SWIOTLB)\n");
98 swiotlb_print_info();
99 }
100 }
101