1 #include <linux/cpu.h> 2 #include <linux/dma-mapping.h> 3 #include <linux/bootmem.h> 4 #include <linux/gfp.h> 5 #include <linux/highmem.h> 6 #include <linux/export.h> 7 #include <linux/of_address.h> 8 #include <linux/slab.h> 9 #include <linux/types.h> 10 #include <linux/dma-mapping.h> 11 #include <linux/vmalloc.h> 12 #include <linux/swiotlb.h> 13 14 #include <xen/xen.h> 15 #include <xen/interface/grant_table.h> 16 #include <xen/interface/memory.h> 17 #include <xen/swiotlb-xen.h> 18 19 #include <asm/cacheflush.h> 20 #include <asm/xen/page.h> 21 #include <asm/xen/hypercall.h> 22 #include <asm/xen/interface.h> 23 24 enum dma_cache_op { 25 DMA_UNMAP, 26 DMA_MAP, 27 }; 28 static bool hypercall_cflush = false; 29 30 /* functions called by SWIOTLB */ 31 32 static void dma_cache_maint(dma_addr_t handle, unsigned long offset, 33 size_t size, enum dma_data_direction dir, enum dma_cache_op op) 34 { 35 struct gnttab_cache_flush cflush; 36 unsigned long pfn; 37 size_t left = size; 38 39 pfn = (handle >> PAGE_SHIFT) + offset / PAGE_SIZE; 40 offset %= PAGE_SIZE; 41 42 do { 43 size_t len = left; 44 45 /* buffers in highmem or foreign pages cannot cross page 46 * boundaries */ 47 if (len + offset > PAGE_SIZE) 48 len = PAGE_SIZE - offset; 49 50 cflush.op = 0; 51 cflush.a.dev_bus_addr = pfn << PAGE_SHIFT; 52 cflush.offset = offset; 53 cflush.length = len; 54 55 if (op == DMA_UNMAP && dir != DMA_TO_DEVICE) 56 cflush.op = GNTTAB_CACHE_INVAL; 57 if (op == DMA_MAP) { 58 if (dir == DMA_FROM_DEVICE) 59 cflush.op = GNTTAB_CACHE_INVAL; 60 else 61 cflush.op = GNTTAB_CACHE_CLEAN; 62 } 63 if (cflush.op) 64 HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1); 65 66 offset = 0; 67 pfn++; 68 left -= len; 69 } while (left); 70 } 71 72 static void __xen_dma_page_dev_to_cpu(struct device *hwdev, dma_addr_t handle, 73 size_t size, enum dma_data_direction dir) 74 { 75 dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_UNMAP); 76 } 77 78 static void __xen_dma_page_cpu_to_dev(struct device *hwdev, dma_addr_t handle, 79 size_t size, enum dma_data_direction dir) 80 { 81 dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_MAP); 82 } 83 84 void __xen_dma_map_page(struct device *hwdev, struct page *page, 85 dma_addr_t dev_addr, unsigned long offset, size_t size, 86 enum dma_data_direction dir, struct dma_attrs *attrs) 87 { 88 if (is_device_dma_coherent(hwdev)) 89 return; 90 if (dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs)) 91 return; 92 93 __xen_dma_page_cpu_to_dev(hwdev, dev_addr, size, dir); 94 } 95 96 void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle, 97 size_t size, enum dma_data_direction dir, 98 struct dma_attrs *attrs) 99 100 { 101 if (is_device_dma_coherent(hwdev)) 102 return; 103 if (dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs)) 104 return; 105 106 __xen_dma_page_dev_to_cpu(hwdev, handle, size, dir); 107 } 108 109 void __xen_dma_sync_single_for_cpu(struct device *hwdev, 110 dma_addr_t handle, size_t size, enum dma_data_direction dir) 111 { 112 if (is_device_dma_coherent(hwdev)) 113 return; 114 __xen_dma_page_dev_to_cpu(hwdev, handle, size, dir); 115 } 116 117 void __xen_dma_sync_single_for_device(struct device *hwdev, 118 dma_addr_t handle, size_t size, enum dma_data_direction dir) 119 { 120 if (is_device_dma_coherent(hwdev)) 121 return; 122 __xen_dma_page_cpu_to_dev(hwdev, handle, size, dir); 123 } 124 125 bool xen_arch_need_swiotlb(struct device *dev, 126 unsigned long pfn, 127 unsigned long mfn) 128 { 129 return (!hypercall_cflush && (pfn != mfn) && !is_device_dma_coherent(dev)); 130 } 131 132 int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order, 133 unsigned int address_bits, 134 dma_addr_t *dma_handle) 135 { 136 if (!xen_initial_domain()) 137 return -EINVAL; 138 139 /* we assume that dom0 is mapped 1:1 for now */ 140 *dma_handle = pstart; 141 return 0; 142 } 143 EXPORT_SYMBOL_GPL(xen_create_contiguous_region); 144 145 void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order) 146 { 147 return; 148 } 149 EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region); 150 151 struct dma_map_ops *xen_dma_ops; 152 EXPORT_SYMBOL_GPL(xen_dma_ops); 153 154 static struct dma_map_ops xen_swiotlb_dma_ops = { 155 .mapping_error = xen_swiotlb_dma_mapping_error, 156 .alloc = xen_swiotlb_alloc_coherent, 157 .free = xen_swiotlb_free_coherent, 158 .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu, 159 .sync_single_for_device = xen_swiotlb_sync_single_for_device, 160 .sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu, 161 .sync_sg_for_device = xen_swiotlb_sync_sg_for_device, 162 .map_sg = xen_swiotlb_map_sg_attrs, 163 .unmap_sg = xen_swiotlb_unmap_sg_attrs, 164 .map_page = xen_swiotlb_map_page, 165 .unmap_page = xen_swiotlb_unmap_page, 166 .dma_supported = xen_swiotlb_dma_supported, 167 .set_dma_mask = xen_swiotlb_set_dma_mask, 168 }; 169 170 int __init xen_mm_init(void) 171 { 172 struct gnttab_cache_flush cflush; 173 if (!xen_initial_domain()) 174 return 0; 175 xen_swiotlb_init(1, false); 176 xen_dma_ops = &xen_swiotlb_dma_ops; 177 178 cflush.op = 0; 179 cflush.a.dev_bus_addr = 0; 180 cflush.offset = 0; 181 cflush.length = 0; 182 if (HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1) != -ENOSYS) 183 hypercall_cflush = true; 184 return 0; 185 } 186 arch_initcall(xen_mm_init); 187