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,struct dma_attrs * attrs)17 void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
18 dma_addr_t *dma_handle, gfp_t flags,
19 struct dma_attrs *attrs)
20 {
21 void *vaddr;
22
23 vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags,
24 attrs);
25 if (vaddr)
26 return vaddr;
27
28 return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
29 }
30
x86_swiotlb_free_coherent(struct device * dev,size_t size,void * vaddr,dma_addr_t dma_addr,struct dma_attrs * attrs)31 void x86_swiotlb_free_coherent(struct device *dev, size_t size,
32 void *vaddr, dma_addr_t dma_addr,
33 struct dma_attrs *attrs)
34 {
35 if (is_swiotlb_buffer(dma_to_phys(dev, dma_addr)))
36 swiotlb_free_coherent(dev, size, vaddr, dma_addr);
37 else
38 dma_generic_free_coherent(dev, size, vaddr, dma_addr, attrs);
39 }
40
41 static struct dma_map_ops swiotlb_dma_ops = {
42 .mapping_error = swiotlb_dma_mapping_error,
43 .alloc = x86_swiotlb_alloc_coherent,
44 .free = x86_swiotlb_free_coherent,
45 .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
46 .sync_single_for_device = swiotlb_sync_single_for_device,
47 .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
48 .sync_sg_for_device = swiotlb_sync_sg_for_device,
49 .map_sg = swiotlb_map_sg_attrs,
50 .unmap_sg = swiotlb_unmap_sg_attrs,
51 .map_page = swiotlb_map_page,
52 .unmap_page = swiotlb_unmap_page,
53 .dma_supported = NULL,
54 };
55
56 /*
57 * pci_swiotlb_detect_override - set swiotlb to 1 if necessary
58 *
59 * This returns non-zero if we are forced to use swiotlb (by the boot
60 * option).
61 */
pci_swiotlb_detect_override(void)62 int __init pci_swiotlb_detect_override(void)
63 {
64 int use_swiotlb = swiotlb | swiotlb_force;
65
66 if (swiotlb_force)
67 swiotlb = 1;
68
69 return use_swiotlb;
70 }
71 IOMMU_INIT_FINISH(pci_swiotlb_detect_override,
72 pci_xen_swiotlb_detect,
73 pci_swiotlb_init,
74 pci_swiotlb_late_init);
75
76 /*
77 * if 4GB or more detected (and iommu=off not set) return 1
78 * and set swiotlb to 1.
79 */
pci_swiotlb_detect_4gb(void)80 int __init pci_swiotlb_detect_4gb(void)
81 {
82 /* don't initialize swiotlb if iommu=off (no_iommu=1) */
83 #ifdef CONFIG_X86_64
84 if (!no_iommu && max_pfn > MAX_DMA32_PFN)
85 swiotlb = 1;
86 #endif
87 return swiotlb;
88 }
89 IOMMU_INIT(pci_swiotlb_detect_4gb,
90 pci_swiotlb_detect_override,
91 pci_swiotlb_init,
92 pci_swiotlb_late_init);
93
pci_swiotlb_init(void)94 void __init pci_swiotlb_init(void)
95 {
96 if (swiotlb) {
97 swiotlb_init(0);
98 dma_ops = &swiotlb_dma_ops;
99 }
100 }
101
pci_swiotlb_late_init(void)102 void __init pci_swiotlb_late_init(void)
103 {
104 /* An IOMMU turned us off. */
105 if (!swiotlb)
106 swiotlb_free();
107 else {
108 printk(KERN_INFO "PCI-DMA: "
109 "Using software bounce buffering for IO (SWIOTLB)\n");
110 swiotlb_print_info();
111 }
112 }
113