drivers/iommu/of_iommu.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * OF helpers for IOMMU
   4  *
   5  * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
   6  */
   7
   8 #include <linux/export.h>
   9 #include <linux/iommu.h>
  10 #include <linux/limits.h>
  11 #include <linux/module.h>
  12 #include <linux/of.h>
  13 #include <linux/of_address.h>
  14 #include <linux/of_iommu.h>
  15 #include <linux/of_pci.h>
  16 #include <linux/pci.h>
  17 #include <linux/slab.h>
  18 #include <linux/fsl/mc.h>
  19
  20 static int of_iommu_xlate(struct device *dev,
  21                           struct of_phandle_args *iommu_spec)
  22 {
  23         const struct iommu_ops *ops;
  24         struct fwnode_handle *fwnode = &iommu_spec->np->fwnode;
  25         int ret;
  26
  27         ops = iommu_ops_from_fwnode(fwnode);
  28         if ((ops && !ops->of_xlate) ||
  29             !of_device_is_available(iommu_spec->np))
  30                 return -ENODEV;
  31
  32         ret = iommu_fwspec_init(dev, fwnode, ops);
  33         if (ret)
  34                 return ret;
  35         /*
  36          * The otherwise-empty fwspec handily serves to indicate the specific
  37          * IOMMU device we're waiting for, which will be useful if we ever get
  38          * a proper probe-ordering dependency mechanism in future.
  39          */
  40         if (!ops)
  41                 return driver_deferred_probe_check_state(dev);
  42
  43         if (!try_module_get(ops->owner))
  44                 return -ENODEV;
  45
  46         ret = ops->of_xlate(dev, iommu_spec);
  47         module_put(ops->owner);
  48         return ret;
  49 }
  50
  51 static int of_iommu_configure_dev_id(struct device_node *master_np,
  52                                      struct device *dev,
  53                                      const u32 *id)
  54 {
  55         struct of_phandle_args iommu_spec = { .args_count = 1 };
  56         int err;
  57
  58         err = of_map_id(master_np, *id, "iommu-map",
  59                          "iommu-map-mask", &iommu_spec.np,
  60                          iommu_spec.args);
  61         if (err)
  62                 return err;
  63
  64         err = of_iommu_xlate(dev, &iommu_spec);
  65         of_node_put(iommu_spec.np);
  66         return err;
  67 }
  68
  69 static int of_iommu_configure_dev(struct device_node *master_np,
  70                                   struct device *dev)
  71 {
  72         struct of_phandle_args iommu_spec;
  73         int err = -ENODEV, idx = 0;
  74
  75         while (!of_parse_phandle_with_args(master_np, "iommus",
  76                                            "#iommu-cells",
  77                                            idx, &iommu_spec)) {
  78                 err = of_iommu_xlate(dev, &iommu_spec);
  79                 of_node_put(iommu_spec.np);
  80                 idx++;
  81                 if (err)
  82                         break;
  83         }
  84
  85         return err;
  86 }
  87
  88 struct of_pci_iommu_alias_info {
  89         struct device *dev;
  90         struct device_node *np;
  91 };
  92
  93 static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data)
  94 {
  95         struct of_pci_iommu_alias_info *info = data;
  96         u32 input_id = alias;
  97
  98         return of_iommu_configure_dev_id(info->np, info->dev, &input_id);
  99 }
 100
 101 static int of_iommu_configure_device(struct device_node *master_np,
 102                                      struct device *dev, const u32 *id)
 103 {
 104         return (id) ? of_iommu_configure_dev_id(master_np, dev, id) :
 105                       of_iommu_configure_dev(master_np, dev);
 106 }
 107
 108 /*
 109  * Returns:
 110  *  0 on success, an iommu was configured
 111  *  -ENODEV if the device does not have any IOMMU
 112  *  -EPROBEDEFER if probing should be tried again
 113  *  -errno fatal errors
 114  */
 115 int of_iommu_configure(struct device *dev, struct device_node *master_np,
 116                        const u32 *id)
 117 {
 118         struct iommu_fwspec *fwspec;
 119         int err;
 120
 121         if (!master_np)
 122                 return -ENODEV;
 123
 124         /* Serialise to make dev->iommu stable under our potential fwspec */
 125         mutex_lock(&iommu_probe_device_lock);
 126         fwspec = dev_iommu_fwspec_get(dev);
 127         if (fwspec) {
 128                 if (fwspec->ops) {
 129                         mutex_unlock(&iommu_probe_device_lock);
 130                         return 0;
 131                 }
 132                 /* In the deferred case, start again from scratch */
 133                 iommu_fwspec_free(dev);
 134         }
 135
 136         /*
 137          * We don't currently walk up the tree looking for a parent IOMMU.
 138          * See the `Notes:' section of
 139          * Documentation/devicetree/bindings/iommu/iommu.txt
 140          */
 141         if (dev_is_pci(dev)) {
 142                 struct of_pci_iommu_alias_info info = {
 143                         .dev = dev,
 144                         .np = master_np,
 145                 };
 146
 147                 pci_request_acs();
 148                 err = pci_for_each_dma_alias(to_pci_dev(dev),
 149                                              of_pci_iommu_init, &info);
 150         } else {
 151                 err = of_iommu_configure_device(master_np, dev, id);
 152         }
 153         mutex_unlock(&iommu_probe_device_lock);
 154
 155         if (err == -ENODEV || err == -EPROBE_DEFER)
 156                 return err;
 157         if (err)
 158                 goto err_log;
 159
 160         err = iommu_probe_device(dev);
 161         if (err)
 162                 goto err_log;
 163         return 0;
 164
 165 err_log:
 166         dev_dbg(dev, "Adding to IOMMU failed: %pe\n", ERR_PTR(err));
 167         return err;
 168 }
 169
 170 static enum iommu_resv_type __maybe_unused
 171 iommu_resv_region_get_type(struct device *dev,
 172                            struct resource *phys,
 173                            phys_addr_t start, size_t length)
 174 {
 175         phys_addr_t end = start + length - 1;
 176
 177         /*
 178          * IOMMU regions without an associated physical region cannot be
 179          * mapped and are simply reservations.
 180          */
 181         if (phys->start >= phys->end)
 182                 return IOMMU_RESV_RESERVED;
 183
 184         /* may be IOMMU_RESV_DIRECT_RELAXABLE for certain cases */
 185         if (start == phys->start && end == phys->end)
 186                 return IOMMU_RESV_DIRECT;
 187
 188         dev_warn(dev, "treating non-direct mapping [%pr] -> [%pap-%pap] as reservation\n", phys,
 189                  &start, &end);
 190         return IOMMU_RESV_RESERVED;
 191 }
 192
 193 /**
 194  * of_iommu_get_resv_regions - reserved region driver helper for device tree
 195  * @dev: device for which to get reserved regions
 196  * @list: reserved region list
 197  *
 198  * IOMMU drivers can use this to implement their .get_resv_regions() callback
 199  * for memory regions attached to a device tree node. See the reserved-memory
 200  * device tree bindings on how to use these:
 201  *
 202  *   Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
 203  */
 204 void of_iommu_get_resv_regions(struct device *dev, struct list_head *list)
 205 {
 206 #if IS_ENABLED(CONFIG_OF_ADDRESS)
 207         struct of_phandle_iterator it;
 208         int err;
 209
 210         of_for_each_phandle(&it, err, dev->of_node, "memory-region", NULL, 0) {
 211                 const __be32 *maps, *end;
 212                 struct resource phys;
 213                 int size;
 214
 215                 memset(&phys, 0, sizeof(phys));
 216
 217                 /*
 218                  * The "reg" property is optional and can be omitted by reserved-memory regions
 219                  * that represent reservations in the IOVA space, which are regions that should
 220                  * not be mapped.
 221                  */
 222                 if (of_find_property(it.node, "reg", NULL)) {
 223                         err = of_address_to_resource(it.node, 0, &phys);
 224                         if (err < 0) {
 225                                 dev_err(dev, "failed to parse memory region %pOF: %d\n",
 226                                         it.node, err);
 227                                 continue;
 228                         }
 229                 }
 230
 231                 maps = of_get_property(it.node, "iommu-addresses", &size);
 232                 if (!maps)
 233                         continue;
 234
 235                 end = maps + size / sizeof(__be32);
 236
 237                 while (maps < end) {
 238                         struct device_node *np;
 239                         u32 phandle;
 240
 241                         phandle = be32_to_cpup(maps++);
 242                         np = of_find_node_by_phandle(phandle);
 243
 244                         if (np == dev->of_node) {
 245                                 int prot = IOMMU_READ | IOMMU_WRITE;
 246                                 struct iommu_resv_region *region;
 247                                 enum iommu_resv_type type;
 248                                 phys_addr_t iova;
 249                                 size_t length;
 250
 251                                 if (of_dma_is_coherent(dev->of_node))
 252                                         prot |= IOMMU_CACHE;
 253
 254                                 maps = of_translate_dma_region(np, maps, &iova, &length);
 255                                 if (length == 0) {
 256                                         dev_warn(dev, "Cannot reserve IOVA region of 0 size\n");
 257                                         continue;
 258                                 }
 259                                 type = iommu_resv_region_get_type(dev, &phys, iova, length);
 260
 261                                 region = iommu_alloc_resv_region(iova, length, prot, type,
 262                                                                  GFP_KERNEL);
 263                                 if (region)
 264                                         list_add_tail(&region->list, list);
 265                         }
 266                 }
 267         }
 268 #endif
 269 }
 270 EXPORT_SYMBOL(of_iommu_get_resv_regions);