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 #include <linux/fsl/mc.h>
  28
  29 #define NO_IOMMU        1
  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 static int of_iommu_xlate(struct device *dev,
 100                           struct of_phandle_args *iommu_spec)
 101 {
 102         const struct iommu_ops *ops;
 103         struct fwnode_handle *fwnode = &iommu_spec->np->fwnode;
 104         int err;
 105
 106         ops = iommu_ops_from_fwnode(fwnode);
 107         if ((ops && !ops->of_xlate) ||
 108             !of_device_is_available(iommu_spec->np))
 109                 return NO_IOMMU;
 110
 111         err = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
 112         if (err)
 113                 return err;
 114         /*
 115          * The otherwise-empty fwspec handily serves to indicate the specific
 116          * IOMMU device we're waiting for, which will be useful if we ever get
 117          * a proper probe-ordering dependency mechanism in future.
 118          */
 119         if (!ops)
 120                 return driver_deferred_probe_check_state(dev);
 121
 122         return ops->of_xlate(dev, iommu_spec);
 123 }
 124
 125 struct of_pci_iommu_alias_info {
 126         struct device *dev;
 127         struct device_node *np;
 128 };
 129
 130 static int of_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data)
 131 {
 132         struct of_pci_iommu_alias_info *info = data;
 133         struct of_phandle_args iommu_spec = { .args_count = 1 };
 134         int err;
 135
 136         err = of_map_rid(info->np, alias, "iommu-map", "iommu-map-mask",
 137                          &iommu_spec.np, iommu_spec.args);
 138         if (err)
 139                 return err == -ENODEV ? NO_IOMMU : err;
 140
 141         err = of_iommu_xlate(info->dev, &iommu_spec);
 142         of_node_put(iommu_spec.np);
 143         return err;
 144 }
 145
 146 static int of_fsl_mc_iommu_init(struct fsl_mc_device *mc_dev,
 147                                 struct device_node *master_np)
 148 {
 149         struct of_phandle_args iommu_spec = { .args_count = 1 };
 150         int err;
 151
 152         err = of_map_rid(master_np, mc_dev->icid, "iommu-map",
 153                          "iommu-map-mask", &iommu_spec.np,
 154                          iommu_spec.args);
 155         if (err)
 156                 return err == -ENODEV ? NO_IOMMU : err;
 157
 158         err = of_iommu_xlate(&mc_dev->dev, &iommu_spec);
 159         of_node_put(iommu_spec.np);
 160         return err;
 161 }
 162
 163 const struct iommu_ops *of_iommu_configure(struct device *dev,
 164                                            struct device_node *master_np)
 165 {
 166         const struct iommu_ops *ops = NULL;
 167         struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
 168         int err = NO_IOMMU;
 169
 170         if (!master_np)
 171                 return NULL;
 172
 173         if (fwspec) {
 174                 if (fwspec->ops)
 175                         return fwspec->ops;
 176
 177                 /* In the deferred case, start again from scratch */
 178                 iommu_fwspec_free(dev);
 179         }
 180
 181         /*
 182          * We don't currently walk up the tree looking for a parent IOMMU.
 183          * See the `Notes:' section of
 184          * Documentation/devicetree/bindings/iommu/iommu.txt
 185          */
 186         if (dev_is_pci(dev)) {
 187                 struct of_pci_iommu_alias_info info = {
 188                         .dev = dev,
 189                         .np = master_np,
 190                 };
 191
 192                 err = pci_for_each_dma_alias(to_pci_dev(dev),
 193                                              of_pci_iommu_init, &info);
 194         } else if (dev_is_fsl_mc(dev)) {
 195                 err = of_fsl_mc_iommu_init(to_fsl_mc_device(dev), master_np);
 196         } else {
 197                 struct of_phandle_args iommu_spec;
 198                 int idx = 0;
 199
 200                 while (!of_parse_phandle_with_args(master_np, "iommus",
 201                                                    "#iommu-cells",
 202                                                    idx, &iommu_spec)) {
 203                         err = of_iommu_xlate(dev, &iommu_spec);
 204                         of_node_put(iommu_spec.np);
 205                         idx++;
 206                         if (err)
 207                                 break;
 208                 }
 209         }
 210
 211
 212         /*
 213          * Two success conditions can be represented by non-negative err here:
 214          * >0 : there is no IOMMU, or one was unavailable for non-fatal reasons
 215          *  0 : we found an IOMMU, and dev->fwspec is initialised appropriately
 216          * <0 : any actual error
 217          */
 218         if (!err) {
 219                 /* The fwspec pointer changed, read it again */
 220                 fwspec = dev_iommu_fwspec_get(dev);
 221                 ops    = fwspec->ops;
 222         }
 223         /*
 224          * If we have reason to believe the IOMMU driver missed the initial
 225          * probe for dev, replay it to get things in order.
 226          */
 227         if (!err && dev->bus && !device_iommu_mapped(dev))
 228                 err = iommu_probe_device(dev);
 229
 230         /* Ignore all other errors apart from EPROBE_DEFER */
 231         if (err == -EPROBE_DEFER) {
 232                 ops = ERR_PTR(err);
 233         } else if (err < 0) {
 234                 dev_dbg(dev, "Adding to IOMMU failed: %d\n", err);
 235                 ops = NULL;
 236         }
 237
 238         return ops;
 239 }