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
14 int swiotlb __read_mostly;
15
swiotlb_alloc_boot(size_t size,unsigned long nslabs)16 void * __init swiotlb_alloc_boot(size_t size, unsigned long nslabs)
17 {
18 return alloc_bootmem_low_pages(size);
19 }
20
swiotlb_alloc(unsigned order,unsigned long nslabs)21 void *swiotlb_alloc(unsigned order, unsigned long nslabs)
22 {
23 return (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN, order);
24 }
25
swiotlb_phys_to_bus(struct device * hwdev,phys_addr_t paddr)26 dma_addr_t swiotlb_phys_to_bus(struct device *hwdev, phys_addr_t paddr)
27 {
28 return paddr;
29 }
30
swiotlb_bus_to_phys(dma_addr_t baddr)31 phys_addr_t swiotlb_bus_to_phys(dma_addr_t baddr)
32 {
33 return baddr;
34 }
35
swiotlb_arch_range_needs_mapping(void * ptr,size_t size)36 int __weak swiotlb_arch_range_needs_mapping(void *ptr, size_t size)
37 {
38 return 0;
39 }
40
41 static dma_addr_t
swiotlb_map_single_phys(struct device * hwdev,phys_addr_t paddr,size_t size,int direction)42 swiotlb_map_single_phys(struct device *hwdev, phys_addr_t paddr, size_t size,
43 int direction)
44 {
45 return swiotlb_map_single(hwdev, phys_to_virt(paddr), size, direction);
46 }
47
x86_swiotlb_alloc_coherent(struct device * hwdev,size_t size,dma_addr_t * dma_handle,gfp_t flags)48 static void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
49 dma_addr_t *dma_handle, gfp_t flags)
50 {
51 void *vaddr;
52
53 vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags);
54 if (vaddr)
55 return vaddr;
56
57 return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
58 }
59
60 struct dma_mapping_ops swiotlb_dma_ops = {
61 .mapping_error = swiotlb_dma_mapping_error,
62 .alloc_coherent = x86_swiotlb_alloc_coherent,
63 .free_coherent = swiotlb_free_coherent,
64 .map_single = swiotlb_map_single_phys,
65 .unmap_single = swiotlb_unmap_single,
66 .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
67 .sync_single_for_device = swiotlb_sync_single_for_device,
68 .sync_single_range_for_cpu = swiotlb_sync_single_range_for_cpu,
69 .sync_single_range_for_device = swiotlb_sync_single_range_for_device,
70 .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
71 .sync_sg_for_device = swiotlb_sync_sg_for_device,
72 .map_sg = swiotlb_map_sg,
73 .unmap_sg = swiotlb_unmap_sg,
74 .dma_supported = NULL,
75 };
76
pci_swiotlb_init(void)77 void __init pci_swiotlb_init(void)
78 {
79 /* don't initialize swiotlb if iommu=off (no_iommu=1) */
80 #ifdef CONFIG_X86_64
81 if (!iommu_detected && !no_iommu && max_pfn > MAX_DMA32_PFN)
82 swiotlb = 1;
83 #endif
84 if (swiotlb_force)
85 swiotlb = 1;
86 if (swiotlb) {
87 printk(KERN_INFO "PCI-DMA: Using software bounce buffering for IO (SWIOTLB)\n");
88 swiotlb_init();
89 dma_ops = &swiotlb_dma_ops;
90 }
91 }
92