drivers/iommu/of_iommu.c

   1 /*
   2  * OF helpers for IOMMU
   3  *
   4  * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include <linux/export.h>
  21 #include <linux/iommu.h>
  22 #include <linux/limits.h>
  23 #include <linux/of.h>
  24 #include <linux/of_iommu.h>
  25 #include <linux/of_pci.h>
  26 #include <linux/slab.h>
  27
  28 static const struct of_device_id __iommu_of_table_sentinel
  29         __used __section(__iommu_of_table_end);
  30
  31 /**
  32  * of_get_dma_window - Parse *dma-window property and returns 0 if found.
  33  *
  34  * @dn: device node
  35  * @prefix: prefix for property name if any
  36  * @index: index to start to parse
  37  * @busno: Returns busno if supported. Otherwise pass NULL
  38  * @addr: Returns address that DMA starts
  39  * @size: Returns the range that DMA can handle
  40  *
  41  * This supports different formats flexibly. "prefix" can be
  42  * configured if any. "busno" and "index" are optionally
  43  * specified. Set 0(or NULL) if not used.
  44  */
  45 int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
  46                       unsigned long *busno, dma_addr_t *addr, size_t *size)
  47 {
  48         const __be32 *dma_window, *end;
  49         int bytes, cur_index = 0;
  50         char propname[NAME_MAX], addrname[NAME_MAX], sizename[NAME_MAX];
  51
  52         if (!dn || !addr || !size)
  53                 return -EINVAL;
  54
  55         if (!prefix)
  56                 prefix = "";
  57
  58         snprintf(propname, sizeof(propname), "%sdma-window", prefix);
  59         snprintf(addrname, sizeof(addrname), "%s#dma-address-cells", prefix);
  60         snprintf(sizename, sizeof(sizename), "%s#dma-size-cells", prefix);
  61
  62         dma_window = of_get_property(dn, propname, &bytes);
  63         if (!dma_window)
  64                 return -ENODEV;
  65         end = dma_window + bytes / sizeof(*dma_window);
  66
  67         while (dma_window < end) {
  68                 u32 cells;
  69                 const void *prop;
  70
  71                 /* busno is one cell if supported */
  72                 if (busno)
  73                         *busno = be32_to_cpup(dma_window++);
  74
  75                 prop = of_get_property(dn, addrname, NULL);
  76                 if (!prop)
  77                         prop = of_get_property(dn, "#address-cells", NULL);
  78
  79                 cells = prop ? be32_to_cpup(prop) : of_n_addr_cells(dn);
  80                 if (!cells)
  81                         return -EINVAL;
  82                 *addr = of_read_number(dma_window, cells);
  83                 dma_window += cells;
  84
  85                 prop = of_get_property(dn, sizename, NULL);
  86                 cells = prop ? be32_to_cpup(prop) : of_n_size_cells(dn);
  87                 if (!cells)
  88                         return -EINVAL;
  89                 *size = of_read_number(dma_window, cells);
  90                 dma_window += cells;
  91
  92                 if (cur_index++ == index)
  93                         break;
  94         }
  95         return 0;
  96 }
  97 EXPORT_SYMBOL_GPL(of_get_dma_window);
  98
  99 struct of_iommu_node {
 100         struct list_head list;
 101         struct device_node *np;
 102         const struct iommu_ops *ops;
 103 };
 104 static LIST_HEAD(of_iommu_list);
 105 static DEFINE_SPINLOCK(of_iommu_lock);
 106
 107 void of_iommu_set_ops(struct device_node *np, const struct iommu_ops *ops)
 108 {
 109         struct of_iommu_node *iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
 110
 111         if (WARN_ON(!iommu))
 112                 return;
 113
 114         of_node_get(np);
 115         INIT_LIST_HEAD(&iommu->list);
 116         iommu->np = np;
 117         iommu->ops = ops;
 118         spin_lock(&of_iommu_lock);
 119         list_add_tail(&iommu->list, &of_iommu_list);
 120         spin_unlock(&of_iommu_lock);
 121 }
 122
 123 const struct iommu_ops *of_iommu_get_ops(struct device_node *np)
 124 {
 125         struct of_iommu_node *node;
 126         const struct iommu_ops *ops = NULL;
 127
 128         spin_lock(&of_iommu_lock);
 129         list_for_each_entry(node, &of_iommu_list, list)
 130                 if (node->np == np) {
 131                         ops = node->ops;
 132                         break;
 133                 }
 134         spin_unlock(&of_iommu_lock);
 135         return ops;
 136 }
 137
 138 static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
 139 {
 140         struct of_phandle_args *iommu_spec = data;
 141
 142         iommu_spec->args[0] = alias;
 143         return iommu_spec->np == pdev->bus->dev.of_node;
 144 }
 145
 146 static const struct iommu_ops
 147 *of_pci_iommu_configure(struct pci_dev *pdev, struct device_node *bridge_np)
 148 {
 149         const struct iommu_ops *ops;
 150         struct of_phandle_args iommu_spec;
 151
 152         /*
 153          * Start by tracing the RID alias down the PCI topology as
 154          * far as the host bridge whose OF node we have...
 155          * (we're not even attempting to handle multi-alias devices yet)
 156          */
 157         iommu_spec.args_count = 1;
 158         iommu_spec.np = bridge_np;
 159         pci_for_each_dma_alias(pdev, __get_pci_rid, &iommu_spec);
 160         /*
 161          * ...then find out what that becomes once it escapes the PCI
 162          * bus into the system beyond, and which IOMMU it ends up at.
 163          */
 164         iommu_spec.np = NULL;
 165         if (of_pci_map_rid(bridge_np, iommu_spec.args[0], "iommu-map",
 166                            "iommu-map-mask", &iommu_spec.np, iommu_spec.args))
 167                 return NULL;
 168
 169         ops = of_iommu_get_ops(iommu_spec.np);
 170         if (!ops || !ops->of_xlate ||
 171             iommu_fwspec_init(&pdev->dev, &iommu_spec.np->fwnode, ops) ||
 172             ops->of_xlate(&pdev->dev, &iommu_spec))
 173                 ops = NULL;
 174
 175         of_node_put(iommu_spec.np);
 176         return ops;
 177 }
 178
 179 const struct iommu_ops *of_iommu_configure(struct device *dev,
 180                                            struct device_node *master_np)
 181 {
 182         struct of_phandle_args iommu_spec;
 183         struct device_node *np;
 184         const struct iommu_ops *ops = NULL;
 185         int idx = 0;
 186
 187         if (dev_is_pci(dev))
 188                 return of_pci_iommu_configure(to_pci_dev(dev), master_np);
 189
 190         /*
 191          * We don't currently walk up the tree looking for a parent IOMMU.
 192          * See the `Notes:' section of
 193          * Documentation/devicetree/bindings/iommu/iommu.txt
 194          */
 195         while (!of_parse_phandle_with_args(master_np, "iommus",
 196                                            "#iommu-cells", idx,
 197                                            &iommu_spec)) {
 198                 np = iommu_spec.np;
 199                 ops = of_iommu_get_ops(np);
 200
 201                 if (!ops || !ops->of_xlate ||
 202                     iommu_fwspec_init(dev, &np->fwnode, ops) ||
 203                     ops->of_xlate(dev, &iommu_spec))
 204                         goto err_put_node;
 205
 206                 of_node_put(np);
 207                 idx++;
 208         }
 209
 210         return ops;
 211
 212 err_put_node:
 213         of_node_put(np);
 214         return NULL;
 215 }
 216
 217 static int __init of_iommu_init(void)
 218 {
 219         struct device_node *np;
 220         const struct of_device_id *match, *matches = &__iommu_of_table;
 221
 222         for_each_matching_node_and_match(np, matches, &match) {
 223                 const of_iommu_init_fn init_fn = match->data;
 224
 225                 if (init_fn(np))
 226                         pr_err("Failed to initialise IOMMU %s\n",
 227                                 of_node_full_name(np));
 228         }
 229
 230         return 0;
 231 }
 232 postcore_initcall_sync(of_iommu_init);