arch/arm/xen/mm.c

   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);