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1 | #include <linux/cpu.h> | |
2 | #include <linux/dma-mapping.h> | |
3 | #include <linux/gfp.h> | |
4 | #include <linux/highmem.h> | |
5 | #include <linux/export.h> | |
6 | #include <linux/memblock.h> | |
7 | #include <linux/of_address.h> | |
8 | #include <linux/slab.h> | |
9 | #include <linux/types.h> | |
10 | #include <linux/vmalloc.h> | |
11 | #include <linux/swiotlb.h> | |
12 | ||
13 | #include <xen/xen.h> | |
14 | #include <xen/interface/grant_table.h> | |
15 | #include <xen/interface/memory.h> | |
16 | #include <xen/page.h> | |
17 | #include <xen/swiotlb-xen.h> | |
18 | ||
19 | #include <asm/cacheflush.h> | |
20 | #include <asm/xen/hypercall.h> | |
21 | #include <asm/xen/interface.h> | |
22 | ||
23 | unsigned long xen_get_swiotlb_free_pages(unsigned int order) | |
24 | { | |
25 | struct memblock_region *reg; | |
26 | gfp_t flags = __GFP_NOWARN|__GFP_KSWAPD_RECLAIM; | |
27 | ||
28 | for_each_memblock(memory, reg) { | |
29 | if (reg->base < (phys_addr_t)0xffffffff) { | |
30 | flags |= __GFP_DMA; | |
31 | break; | |
32 | } | |
33 | } | |
34 | return __get_free_pages(flags, order); | |
35 | } | |
36 | ||
37 | enum dma_cache_op { | |
38 | DMA_UNMAP, | |
39 | DMA_MAP, | |
40 | }; | |
41 | static bool hypercall_cflush = false; | |
42 | ||
43 | /* functions called by SWIOTLB */ | |
44 | ||
45 | static void dma_cache_maint(dma_addr_t handle, unsigned long offset, | |
46 | size_t size, enum dma_data_direction dir, enum dma_cache_op op) | |
47 | { | |
48 | struct gnttab_cache_flush cflush; | |
49 | unsigned long xen_pfn; | |
50 | size_t left = size; | |
51 | ||
52 | xen_pfn = (handle >> XEN_PAGE_SHIFT) + offset / XEN_PAGE_SIZE; | |
53 | offset %= XEN_PAGE_SIZE; | |
54 | ||
55 | do { | |
56 | size_t len = left; | |
57 | ||
58 | /* buffers in highmem or foreign pages cannot cross page | |
59 | * boundaries */ | |
60 | if (len + offset > XEN_PAGE_SIZE) | |
61 | len = XEN_PAGE_SIZE - offset; | |
62 | ||
63 | cflush.op = 0; | |
64 | cflush.a.dev_bus_addr = xen_pfn << XEN_PAGE_SHIFT; | |
65 | cflush.offset = offset; | |
66 | cflush.length = len; | |
67 | ||
68 | if (op == DMA_UNMAP && dir != DMA_TO_DEVICE) | |
69 | cflush.op = GNTTAB_CACHE_INVAL; | |
70 | if (op == DMA_MAP) { | |
71 | if (dir == DMA_FROM_DEVICE) | |
72 | cflush.op = GNTTAB_CACHE_INVAL; | |
73 | else | |
74 | cflush.op = GNTTAB_CACHE_CLEAN; | |
75 | } | |
76 | if (cflush.op) | |
77 | HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1); | |
78 | ||
79 | offset = 0; | |
80 | xen_pfn++; | |
81 | left -= len; | |
82 | } while (left); | |
83 | } | |
84 | ||
85 | static void __xen_dma_page_dev_to_cpu(struct device *hwdev, dma_addr_t handle, | |
86 | size_t size, enum dma_data_direction dir) | |
87 | { | |
88 | dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_UNMAP); | |
89 | } | |
90 | ||
91 | static void __xen_dma_page_cpu_to_dev(struct device *hwdev, dma_addr_t handle, | |
92 | size_t size, enum dma_data_direction dir) | |
93 | { | |
94 | dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_MAP); | |
95 | } | |
96 | ||
97 | void __xen_dma_map_page(struct device *hwdev, struct page *page, | |
98 | dma_addr_t dev_addr, unsigned long offset, size_t size, | |
99 | enum dma_data_direction dir, unsigned long attrs) | |
100 | { | |
101 | if (is_device_dma_coherent(hwdev)) | |
102 | return; | |
103 | if (attrs & DMA_ATTR_SKIP_CPU_SYNC) | |
104 | return; | |
105 | ||
106 | __xen_dma_page_cpu_to_dev(hwdev, dev_addr, size, dir); | |
107 | } | |
108 | ||
109 | void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle, | |
110 | size_t size, enum dma_data_direction dir, | |
111 | unsigned long attrs) | |
112 | ||
113 | { | |
114 | if (is_device_dma_coherent(hwdev)) | |
115 | return; | |
116 | if (attrs & DMA_ATTR_SKIP_CPU_SYNC) | |
117 | return; | |
118 | ||
119 | __xen_dma_page_dev_to_cpu(hwdev, handle, size, dir); | |
120 | } | |
121 | ||
122 | void __xen_dma_sync_single_for_cpu(struct device *hwdev, | |
123 | dma_addr_t handle, size_t size, enum dma_data_direction dir) | |
124 | { | |
125 | if (is_device_dma_coherent(hwdev)) | |
126 | return; | |
127 | __xen_dma_page_dev_to_cpu(hwdev, handle, size, dir); | |
128 | } | |
129 | ||
130 | void __xen_dma_sync_single_for_device(struct device *hwdev, | |
131 | dma_addr_t handle, size_t size, enum dma_data_direction dir) | |
132 | { | |
133 | if (is_device_dma_coherent(hwdev)) | |
134 | return; | |
135 | __xen_dma_page_cpu_to_dev(hwdev, handle, size, dir); | |
136 | } | |
137 | ||
138 | bool xen_arch_need_swiotlb(struct device *dev, | |
139 | phys_addr_t phys, | |
140 | dma_addr_t dev_addr) | |
141 | { | |
142 | unsigned int xen_pfn = XEN_PFN_DOWN(phys); | |
143 | unsigned int bfn = XEN_PFN_DOWN(dev_addr); | |
144 | ||
145 | /* | |
146 | * The swiotlb buffer should be used if | |
147 | * - Xen doesn't have the cache flush hypercall | |
148 | * - The Linux page refers to foreign memory | |
149 | * - The device doesn't support coherent DMA request | |
150 | * | |
151 | * The Linux page may be spanned acrros multiple Xen page, although | |
152 | * it's not possible to have a mix of local and foreign Xen page. | |
153 | * Furthermore, range_straddles_page_boundary is already checking | |
154 | * if buffer is physically contiguous in the host RAM. | |
155 | * | |
156 | * Therefore we only need to check the first Xen page to know if we | |
157 | * require a bounce buffer because the device doesn't support coherent | |
158 | * memory and we are not able to flush the cache. | |
159 | */ | |
160 | return (!hypercall_cflush && (xen_pfn != bfn) && | |
161 | !is_device_dma_coherent(dev)); | |
162 | } | |
163 | ||
164 | int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order, | |
165 | unsigned int address_bits, | |
166 | dma_addr_t *dma_handle) | |
167 | { | |
168 | if (!xen_initial_domain()) | |
169 | return -EINVAL; | |
170 | ||
171 | /* we assume that dom0 is mapped 1:1 for now */ | |
172 | *dma_handle = pstart; | |
173 | return 0; | |
174 | } | |
175 | EXPORT_SYMBOL_GPL(xen_create_contiguous_region); | |
176 | ||
177 | void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order) | |
178 | { | |
179 | return; | |
180 | } | |
181 | EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region); | |
182 | ||
183 | const struct dma_map_ops *xen_dma_ops; | |
184 | EXPORT_SYMBOL(xen_dma_ops); | |
185 | ||
186 | int __init xen_mm_init(void) | |
187 | { | |
188 | struct gnttab_cache_flush cflush; | |
189 | if (!xen_initial_domain()) | |
190 | return 0; | |
191 | xen_swiotlb_init(1, false); | |
192 | xen_dma_ops = &xen_swiotlb_dma_ops; | |
193 | ||
194 | cflush.op = 0; | |
195 | cflush.a.dev_bus_addr = 0; | |
196 | cflush.offset = 0; | |
197 | cflush.length = 0; | |
198 | if (HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1) != -ENOSYS) | |
199 | hypercall_cflush = true; | |
200 | return 0; | |
201 | } | |
202 | arch_initcall(xen_mm_init); |