arch/powerpc/kernel/dma-iommu.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
   4  *
   5  * Provide default implementations of the DMA mapping callbacks for
   6  * busses using the iommu infrastructure
   7  */
   8
   9 #include <linux/dma-direct.h>
  10 #include <linux/pci.h>
  11 #include <asm/iommu.h>
  12
  13 #ifdef CONFIG_ARCH_HAS_DMA_MAP_DIRECT
  14 #define can_map_direct(dev, addr) \
  15         ((dev)->bus_dma_limit >= phys_to_dma((dev), (addr)))
  16
  17 bool arch_dma_map_page_direct(struct device *dev, phys_addr_t addr)
  18 {
  19         if (likely(!dev->bus_dma_limit))
  20                 return false;
  21
  22         return can_map_direct(dev, addr);
  23 }
  24
  25 #define is_direct_handle(dev, h) ((h) >= (dev)->archdata.dma_offset)
  26
  27 bool arch_dma_unmap_page_direct(struct device *dev, dma_addr_t dma_handle)
  28 {
  29         if (likely(!dev->bus_dma_limit))
  30                 return false;
  31
  32         return is_direct_handle(dev, dma_handle);
  33 }
  34
  35 bool arch_dma_map_sg_direct(struct device *dev, struct scatterlist *sg,
  36                             int nents)
  37 {
  38         struct scatterlist *s;
  39         int i;
  40
  41         if (likely(!dev->bus_dma_limit))
  42                 return false;
  43
  44         for_each_sg(sg, s, nents, i) {
  45                 if (!can_map_direct(dev, sg_phys(s) + s->offset + s->length))
  46                         return false;
  47         }
  48
  49         return true;
  50 }
  51
  52 bool arch_dma_unmap_sg_direct(struct device *dev, struct scatterlist *sg,
  53                               int nents)
  54 {
  55         struct scatterlist *s;
  56         int i;
  57
  58         if (likely(!dev->bus_dma_limit))
  59                 return false;
  60
  61         for_each_sg(sg, s, nents, i) {
  62                 if (!is_direct_handle(dev, s->dma_address + s->length))
  63                         return false;
  64         }
  65
  66         return true;
  67 }
  68 #endif /* CONFIG_ARCH_HAS_DMA_MAP_DIRECT */
  69
  70 /*
  71  * Generic iommu implementation
  72  */
  73
  74 /* Allocates a contiguous real buffer and creates mappings over it.
  75  * Returns the virtual address of the buffer and sets dma_handle
  76  * to the dma address (mapping) of the first page.
  77  */
  78 static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
  79                                       dma_addr_t *dma_handle, gfp_t flag,
  80                                       unsigned long attrs)
  81 {
  82         return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
  83                                     dma_handle, dev->coherent_dma_mask, flag,
  84                                     dev_to_node(dev));
  85 }
  86
  87 static void dma_iommu_free_coherent(struct device *dev, size_t size,
  88                                     void *vaddr, dma_addr_t dma_handle,
  89                                     unsigned long attrs)
  90 {
  91         iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
  92 }
  93
  94 /* Creates TCEs for a user provided buffer.  The user buffer must be
  95  * contiguous real kernel storage (not vmalloc).  The address passed here
  96  * comprises a page address and offset into that page. The dma_addr_t
  97  * returned will point to the same byte within the page as was passed in.
  98  */
  99 static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page,
 100                                      unsigned long offset, size_t size,
 101                                      enum dma_data_direction direction,
 102                                      unsigned long attrs)
 103 {
 104         return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
 105                               size, dma_get_mask(dev), direction, attrs);
 106 }
 107
 108
 109 static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
 110                                  size_t size, enum dma_data_direction direction,
 111                                  unsigned long attrs)
 112 {
 113         iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,
 114                          attrs);
 115 }
 116
 117
 118 static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
 119                             int nelems, enum dma_data_direction direction,
 120                             unsigned long attrs)
 121 {
 122         return ppc_iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
 123                                 dma_get_mask(dev), direction, attrs);
 124 }
 125
 126 static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
 127                 int nelems, enum dma_data_direction direction,
 128                 unsigned long attrs)
 129 {
 130         ppc_iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems,
 131                            direction, attrs);
 132 }
 133
 134 static bool dma_iommu_bypass_supported(struct device *dev, u64 mask)
 135 {
 136         struct pci_dev *pdev = to_pci_dev(dev);
 137         struct pci_controller *phb = pci_bus_to_host(pdev->bus);
 138
 139         if (iommu_fixed_is_weak || !phb->controller_ops.iommu_bypass_supported)
 140                 return false;
 141         return phb->controller_ops.iommu_bypass_supported(pdev, mask);
 142 }
 143
 144 /* We support DMA to/from any memory page via the iommu */
 145 int dma_iommu_dma_supported(struct device *dev, u64 mask)
 146 {
 147         struct iommu_table *tbl = get_iommu_table_base(dev);
 148
 149         if (dev_is_pci(dev) && dma_iommu_bypass_supported(dev, mask)) {
 150                 /*
 151                  * dma_iommu_bypass_supported() sets dma_max when there is
 152                  * 1:1 mapping but it is somehow limited.
 153                  * ibm,pmemory is one example.
 154                  */
 155                 dev->dma_ops_bypass = dev->bus_dma_limit == 0;
 156                 if (!dev->dma_ops_bypass)
 157                         dev_warn(dev,
 158                                  "iommu: 64-bit OK but direct DMA is limited by %llx\n",
 159                                  dev->bus_dma_limit);
 160                 else
 161                         dev_dbg(dev, "iommu: 64-bit OK, using fixed ops\n");
 162                 return 1;
 163         }
 164
 165         if (!tbl) {
 166                 dev_err(dev, "Warning: IOMMU dma not supported: mask 0x%08llx, table unavailable\n", mask);
 167                 return 0;
 168         }
 169
 170         if (tbl->it_offset > (mask >> tbl->it_page_shift)) {
 171                 dev_info(dev, "Warning: IOMMU offset too big for device mask\n");
 172                 dev_info(dev, "mask: 0x%08llx, table offset: 0x%08lx\n",
 173                                 mask, tbl->it_offset << tbl->it_page_shift);
 174                 return 0;
 175         }
 176
 177         dev_dbg(dev, "iommu: not 64-bit, using default ops\n");
 178         dev->dma_ops_bypass = false;
 179         return 1;
 180 }
 181
 182 u64 dma_iommu_get_required_mask(struct device *dev)
 183 {
 184         struct iommu_table *tbl = get_iommu_table_base(dev);
 185         u64 mask;
 186
 187         if (!tbl)
 188                 return 0;
 189
 190         mask = 1ULL << (fls_long(tbl->it_offset + tbl->it_size) +
 191                         tbl->it_page_shift - 1);
 192         mask += mask - 1;
 193
 194         return mask;
 195 }
 196
 197 const struct dma_map_ops dma_iommu_ops = {
 198         .alloc                  = dma_iommu_alloc_coherent,
 199         .free                   = dma_iommu_free_coherent,
 200         .map_sg                 = dma_iommu_map_sg,
 201         .unmap_sg               = dma_iommu_unmap_sg,
 202         .dma_supported          = dma_iommu_dma_supported,
 203         .map_page               = dma_iommu_map_page,
 204         .unmap_page             = dma_iommu_unmap_page,
 205         .get_required_mask      = dma_iommu_get_required_mask,
 206         .mmap                   = dma_common_mmap,
 207         .get_sgtable            = dma_common_get_sgtable,
 208         .alloc_pages            = dma_common_alloc_pages,
 209         .free_pages             = dma_common_free_pages,
 210 };