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 /*
24 * Don't print a warning when the first allocation attempt fails.
25 * swiotlb_alloc_coherent() will print a warning when the DMA
26 * memory allocation ultimately failed.
27 */
28 flags |= __GFP_NOWARN;
29
30 vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags,
31 attrs);
32 if (vaddr)
33 return vaddr;
34
35 return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
36 }
37
x86_swiotlb_free_coherent(struct device * dev,size_t size,void * vaddr,dma_addr_t dma_addr,struct dma_attrs * attrs)38 void x86_swiotlb_free_coherent(struct device *dev, size_t size,
39 void *vaddr, dma_addr_t dma_addr,
40 struct dma_attrs *attrs)
41 {
42 if (is_swiotlb_buffer(dma_to_phys(dev, dma_addr)))
43 swiotlb_free_coherent(dev, size, vaddr, dma_addr);
44 else
45 dma_generic_free_coherent(dev, size, vaddr, dma_addr, attrs);
46 }
47
48 static struct dma_map_ops swiotlb_dma_ops = {
49 .mapping_error = swiotlb_dma_mapping_error,
50 .alloc = x86_swiotlb_alloc_coherent,
51 .free = x86_swiotlb_free_coherent,
52 .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
53 .sync_single_for_device = swiotlb_sync_single_for_device,
54 .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
55 .sync_sg_for_device = swiotlb_sync_sg_for_device,
56 .map_sg = swiotlb_map_sg_attrs,
57 .unmap_sg = swiotlb_unmap_sg_attrs,
58 .map_page = swiotlb_map_page,
59 .unmap_page = swiotlb_unmap_page,
60 .dma_supported = NULL,
61 };
62
63 /*
64 * pci_swiotlb_detect_override - set swiotlb to 1 if necessary
65 *
66 * This returns non-zero if we are forced to use swiotlb (by the boot
67 * option).
68 */
pci_swiotlb_detect_override(void)69 int __init pci_swiotlb_detect_override(void)
70 {
71 int use_swiotlb = swiotlb | swiotlb_force;
72
73 if (swiotlb_force)
74 swiotlb = 1;
75
76 return use_swiotlb;
77 }
78 IOMMU_INIT_FINISH(pci_swiotlb_detect_override,
79 pci_xen_swiotlb_detect,
80 pci_swiotlb_init,
81 pci_swiotlb_late_init);
82
83 /*
84 * if 4GB or more detected (and iommu=off not set) return 1
85 * and set swiotlb to 1.
86 */
pci_swiotlb_detect_4gb(void)87 int __init pci_swiotlb_detect_4gb(void)
88 {
89 /* don't initialize swiotlb if iommu=off (no_iommu=1) */
90 #ifdef CONFIG_X86_64
91 if (!no_iommu && max_pfn > MAX_DMA32_PFN)
92 swiotlb = 1;
93 #endif
94 return swiotlb;
95 }
96 IOMMU_INIT(pci_swiotlb_detect_4gb,
97 pci_swiotlb_detect_override,
98 pci_swiotlb_init,
99 pci_swiotlb_late_init);
100
pci_swiotlb_init(void)101 void __init pci_swiotlb_init(void)
102 {
103 if (swiotlb) {
104 swiotlb_init(0);
105 dma_ops = &swiotlb_dma_ops;
106 }
107 }
108
pci_swiotlb_late_init(void)109 void __init pci_swiotlb_late_init(void)
110 {
111 /* An IOMMU turned us off. */
112 if (!swiotlb)
113 swiotlb_free();
114 else {
115 printk(KERN_INFO "PCI-DMA: "
116 "Using software bounce buffering for IO (SWIOTLB)\n");
117 swiotlb_print_info();
118 }
119 }
120