drivers/of/device.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/kernel.h>
   3 #include <linux/of.h>
   4 #include <linux/of_device.h>
   5 #include <linux/of_address.h>
   6 #include <linux/of_iommu.h>
   7 #include <linux/of_reserved_mem.h>
   8 #include <linux/dma-direct.h> /* for bus_dma_region */
   9 #include <linux/dma-map-ops.h>
  10 #include <linux/init.h>
  11 #include <linux/mod_devicetable.h>
  12 #include <linux/slab.h>
  13 #include <linux/platform_device.h>
  14
  15 #include <asm/errno.h>
  16 #include "of_private.h"
  17
  18 /**
  19  * of_match_device - Tell if a struct device matches an of_device_id list
  20  * @matches: array of of device match structures to search in
  21  * @dev: the of device structure to match against
  22  *
  23  * Used by a driver to check whether an platform_device present in the
  24  * system is in its list of supported devices.
  25  */
  26 const struct of_device_id *of_match_device(const struct of_device_id *matches,
  27                                            const struct device *dev)
  28 {
  29         if (!matches || !dev->of_node || dev->of_node_reused)
  30                 return NULL;
  31         return of_match_node(matches, dev->of_node);
  32 }
  33 EXPORT_SYMBOL(of_match_device);
  34
  35 static void
  36 of_dma_set_restricted_buffer(struct device *dev, struct device_node *np)
  37 {
  38         struct device_node *node, *of_node = dev->of_node;
  39         int count, i;
  40
  41         if (!IS_ENABLED(CONFIG_DMA_RESTRICTED_POOL))
  42                 return;
  43
  44         count = of_property_count_elems_of_size(of_node, "memory-region",
  45                                                 sizeof(u32));
  46         /*
  47          * If dev->of_node doesn't exist or doesn't contain memory-region, try
  48          * the OF node having DMA configuration.
  49          */
  50         if (count <= 0) {
  51                 of_node = np;
  52                 count = of_property_count_elems_of_size(
  53                         of_node, "memory-region", sizeof(u32));
  54         }
  55
  56         for (i = 0; i < count; i++) {
  57                 node = of_parse_phandle(of_node, "memory-region", i);
  58                 /*
  59                  * There might be multiple memory regions, but only one
  60                  * restricted-dma-pool region is allowed.
  61                  */
  62                 if (of_device_is_compatible(node, "restricted-dma-pool") &&
  63                     of_device_is_available(node)) {
  64                         of_node_put(node);
  65                         break;
  66                 }
  67                 of_node_put(node);
  68         }
  69
  70         /*
  71          * Attempt to initialize a restricted-dma-pool region if one was found.
  72          * Note that count can hold a negative error code.
  73          */
  74         if (i < count && of_reserved_mem_device_init_by_idx(dev, of_node, i))
  75                 dev_warn(dev, "failed to initialise \"restricted-dma-pool\" memory node\n");
  76 }
  77
  78 /**
  79  * of_dma_configure_id - Setup DMA configuration
  80  * @dev:        Device to apply DMA configuration
  81  * @np:         Pointer to OF node having DMA configuration
  82  * @force_dma:  Whether device is to be set up by of_dma_configure() even if
  83  *              DMA capability is not explicitly described by firmware.
  84  * @id:         Optional const pointer value input id
  85  *
  86  * Try to get devices's DMA configuration from DT and update it
  87  * accordingly.
  88  *
  89  * If platform code needs to use its own special DMA configuration, it
  90  * can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
  91  * to fix up DMA configuration.
  92  */
  93 int of_dma_configure_id(struct device *dev, struct device_node *np,
  94                         bool force_dma, const u32 *id)
  95 {
  96         const struct bus_dma_region *map = NULL;
  97         struct device_node *bus_np;
  98         u64 mask, end = 0;
  99         bool coherent, set_map = false;
 100         int ret;
 101
 102         if (np == dev->of_node)
 103                 bus_np = __of_get_dma_parent(np);
 104         else
 105                 bus_np = of_node_get(np);
 106
 107         ret = of_dma_get_range(bus_np, &map);
 108         of_node_put(bus_np);
 109         if (ret < 0) {
 110                 /*
 111                  * For legacy reasons, we have to assume some devices need
 112                  * DMA configuration regardless of whether "dma-ranges" is
 113                  * correctly specified or not.
 114                  */
 115                 if (!force_dma)
 116                         return ret == -ENODEV ? 0 : ret;
 117         } else {
 118                 /* Determine the overall bounds of all DMA regions */
 119                 end = dma_range_map_max(map);
 120                 set_map = true;
 121         }
 122
 123         /*
 124          * If @dev is expected to be DMA-capable then the bus code that created
 125          * it should have initialised its dma_mask pointer by this point. For
 126          * now, we'll continue the legacy behaviour of coercing it to the
 127          * coherent mask if not, but we'll no longer do so quietly.
 128          */
 129         if (!dev->dma_mask) {
 130                 dev_warn(dev, "DMA mask not set\n");
 131                 dev->dma_mask = &dev->coherent_dma_mask;
 132         }
 133
 134         if (!end && dev->coherent_dma_mask)
 135                 end = dev->coherent_dma_mask;
 136         else if (!end)
 137                 end = (1ULL << 32) - 1;
 138
 139         /*
 140          * Limit coherent and dma mask based on size and default mask
 141          * set by the driver.
 142          */
 143         mask = DMA_BIT_MASK(ilog2(end) + 1);
 144         dev->coherent_dma_mask &= mask;
 145         *dev->dma_mask &= mask;
 146         /* ...but only set bus limit and range map if we found valid dma-ranges earlier */
 147         if (set_map) {
 148                 dev->bus_dma_limit = end;
 149                 dev->dma_range_map = map;
 150         }
 151
 152         coherent = of_dma_is_coherent(np);
 153         dev_dbg(dev, "device is%sdma coherent\n",
 154                 coherent ? " " : " not ");
 155
 156         ret = of_iommu_configure(dev, np, id);
 157         if (ret == -EPROBE_DEFER) {
 158                 /* Don't touch range map if it wasn't set from a valid dma-ranges */
 159                 if (set_map)
 160                         dev->dma_range_map = NULL;
 161                 kfree(map);
 162                 return -EPROBE_DEFER;
 163         }
 164         /* Take all other IOMMU errors to mean we'll just carry on without it */
 165         dev_dbg(dev, "device is%sbehind an iommu\n",
 166                 !ret ? " " : " not ");
 167
 168         arch_setup_dma_ops(dev, coherent);
 169
 170         if (ret)
 171                 of_dma_set_restricted_buffer(dev, np);
 172
 173         return 0;
 174 }
 175 EXPORT_SYMBOL_GPL(of_dma_configure_id);
 176
 177 const void *of_device_get_match_data(const struct device *dev)
 178 {
 179         const struct of_device_id *match;
 180
 181         match = of_match_device(dev->driver->of_match_table, dev);
 182         if (!match)
 183                 return NULL;
 184
 185         return match->data;
 186 }
 187 EXPORT_SYMBOL(of_device_get_match_data);
 188
 189 /**
 190  * of_device_modalias - Fill buffer with newline terminated modalias string
 191  * @dev:        Calling device
 192  * @str:        Modalias string
 193  * @len:        Size of @str
 194  */
 195 ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len)
 196 {
 197         ssize_t sl;
 198
 199         if (!dev || !dev->of_node || dev->of_node_reused)
 200                 return -ENODEV;
 201
 202         sl = of_modalias(dev->of_node, str, len - 2);
 203         if (sl < 0)
 204                 return sl;
 205         if (sl > len - 2)
 206                 return -ENOMEM;
 207
 208         str[sl++] = '\n';
 209         str[sl] = 0;
 210         return sl;
 211 }
 212 EXPORT_SYMBOL_GPL(of_device_modalias);
 213
 214 /**
 215  * of_device_uevent - Display OF related uevent information
 216  * @dev:        Device to display the uevent information for
 217  * @env:        Kernel object's userspace event reference to fill up
 218  */
 219 void of_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
 220 {
 221         const char *compat, *type;
 222         struct alias_prop *app;
 223         struct property *p;
 224         int seen = 0;
 225
 226         if ((!dev) || (!dev->of_node))
 227                 return;
 228
 229         add_uevent_var(env, "OF_NAME=%pOFn", dev->of_node);
 230         add_uevent_var(env, "OF_FULLNAME=%pOF", dev->of_node);
 231         type = of_node_get_device_type(dev->of_node);
 232         if (type)
 233                 add_uevent_var(env, "OF_TYPE=%s", type);
 234
 235         /* Since the compatible field can contain pretty much anything
 236          * it's not really legal to split it out with commas. We split it
 237          * up using a number of environment variables instead. */
 238         of_property_for_each_string(dev->of_node, "compatible", p, compat) {
 239                 add_uevent_var(env, "OF_COMPATIBLE_%d=%s", seen, compat);
 240                 seen++;
 241         }
 242         add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen);
 243
 244         seen = 0;
 245         mutex_lock(&of_mutex);
 246         list_for_each_entry(app, &aliases_lookup, link) {
 247                 if (dev->of_node == app->np) {
 248                         add_uevent_var(env, "OF_ALIAS_%d=%s", seen,
 249                                        app->alias);
 250                         seen++;
 251                 }
 252         }
 253         mutex_unlock(&of_mutex);
 254 }
 255 EXPORT_SYMBOL_GPL(of_device_uevent);
 256
 257 int of_device_uevent_modalias(const struct device *dev, struct kobj_uevent_env *env)
 258 {
 259         int sl;
 260
 261         if ((!dev) || (!dev->of_node) || dev->of_node_reused)
 262                 return -ENODEV;
 263
 264         /* Devicetree modalias is tricky, we add it in 2 steps */
 265         if (add_uevent_var(env, "MODALIAS="))
 266                 return -ENOMEM;
 267
 268         sl = of_modalias(dev->of_node, &env->buf[env->buflen-1],
 269                          sizeof(env->buf) - env->buflen);
 270         if (sl < 0)
 271                 return sl;
 272         if (sl >= (sizeof(env->buf) - env->buflen))
 273                 return -ENOMEM;
 274         env->buflen += sl;
 275
 276         return 0;
 277 }
 278 EXPORT_SYMBOL_GPL(of_device_uevent_modalias);
 279
 280 /**
 281  * of_device_make_bus_id - Use the device node data to assign a unique name
 282  * @dev: pointer to device structure that is linked to a device tree node
 283  *
 284  * This routine will first try using the translated bus address to
 285  * derive a unique name. If it cannot, then it will prepend names from
 286  * parent nodes until a unique name can be derived.
 287  */
 288 void of_device_make_bus_id(struct device *dev)
 289 {
 290         struct device_node *node = dev->of_node;
 291         const __be32 *reg;
 292         u64 addr;
 293         u32 mask;
 294
 295         /* Construct the name, using parent nodes if necessary to ensure uniqueness */
 296         while (node->parent) {
 297                 /*
 298                  * If the address can be translated, then that is as much
 299                  * uniqueness as we need. Make it the first component and return
 300                  */
 301                 reg = of_get_property(node, "reg", NULL);
 302                 if (reg && (addr = of_translate_address(node, reg)) != OF_BAD_ADDR) {
 303                         if (!of_property_read_u32(node, "mask", &mask))
 304                                 dev_set_name(dev, dev_name(dev) ? "%llx.%x.%pOFn:%s" : "%llx.%x.%pOFn",
 305                                              addr, ffs(mask) - 1, node, dev_name(dev));
 306
 307                         else
 308                                 dev_set_name(dev, dev_name(dev) ? "%llx.%pOFn:%s" : "%llx.%pOFn",
 309                                              addr, node, dev_name(dev));
 310                         return;
 311                 }
 312
 313                 /* format arguments only used if dev_name() resolves to NULL */
 314                 dev_set_name(dev, dev_name(dev) ? "%s:%s" : "%s",
 315                              kbasename(node->full_name), dev_name(dev));
 316                 node = node->parent;
 317         }
 318 }
 319 EXPORT_SYMBOL_GPL(of_device_make_bus_id);