root/drivers/pci/of.c

DEFINITIONS

1. pci_set_of_node
2. pci_release_of_node
3. pci_set_bus_of_node
4. pci_release_bus_of_node
5. pcibios_get_phb_of_node
6. pci_host_bridge_of_msi_domain
7. __of_pci_pci_compare
8. of_pci_find_child_device
9. of_pci_get_devfn
10. of_pci_parse_bus_range
11. of_get_pci_domain_nr
12. of_pci_check_probe_only
13. devm_of_pci_get_host_bridge_resources
14. of_irq_parse_pci
15. of_irq_parse_and_map_pci
16. pci_parse_request_of_pci_ranges
17. of_pci_get_max_link_speed

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * PCI <-> OF mapping helpers
   4  *
   5  * Copyright 2011 IBM Corp.
   6  */
   7 #define pr_fmt(fmt)     "PCI: OF: " fmt
   8 
   9 #include <linux/irqdomain.h>
  10 #include <linux/kernel.h>
  11 #include <linux/pci.h>
  12 #include <linux/of.h>
  13 #include <linux/of_irq.h>
  14 #include <linux/of_address.h>
  15 #include <linux/of_pci.h>
  16 #include "pci.h"
  17 
  18 #ifdef CONFIG_PCI
  19 void pci_set_of_node(struct pci_dev *dev)
  20 {
  21         if (!dev->bus->dev.of_node)
  22                 return;
  23         dev->dev.of_node = of_pci_find_child_device(dev->bus->dev.of_node,
  24                                                     dev->devfn);
  25         if (dev->dev.of_node)
  26                 dev->dev.fwnode = &dev->dev.of_node->fwnode;
  27 }
  28 
  29 void pci_release_of_node(struct pci_dev *dev)
  30 {
  31         of_node_put(dev->dev.of_node);
  32         dev->dev.of_node = NULL;
  33         dev->dev.fwnode = NULL;
  34 }
  35 
  36 void pci_set_bus_of_node(struct pci_bus *bus)
  37 {
  38         struct device_node *node;
  39 
  40         if (bus->self == NULL) {
  41                 node = pcibios_get_phb_of_node(bus);
  42         } else {
  43                 node = of_node_get(bus->self->dev.of_node);
  44                 if (node && of_property_read_bool(node, "external-facing"))
  45                         bus->self->untrusted = true;
  46         }
  47 
  48         bus->dev.of_node = node;
  49 
  50         if (bus->dev.of_node)
  51                 bus->dev.fwnode = &bus->dev.of_node->fwnode;
  52 }
  53 
  54 void pci_release_bus_of_node(struct pci_bus *bus)
  55 {
  56         of_node_put(bus->dev.of_node);
  57         bus->dev.of_node = NULL;
  58         bus->dev.fwnode = NULL;
  59 }
  60 
  61 struct device_node * __weak pcibios_get_phb_of_node(struct pci_bus *bus)
  62 {
  63         /* This should only be called for PHBs */
  64         if (WARN_ON(bus->self || bus->parent))
  65                 return NULL;
  66 
  67         /*
  68          * Look for a node pointer in either the intermediary device we
  69          * create above the root bus or its own parent. Normally only
  70          * the later is populated.
  71          */
  72         if (bus->bridge->of_node)
  73                 return of_node_get(bus->bridge->of_node);
  74         if (bus->bridge->parent && bus->bridge->parent->of_node)
  75                 return of_node_get(bus->bridge->parent->of_node);
  76         return NULL;
  77 }
  78 
  79 struct irq_domain *pci_host_bridge_of_msi_domain(struct pci_bus *bus)
  80 {
  81 #ifdef CONFIG_IRQ_DOMAIN
  82         struct irq_domain *d;
  83 
  84         if (!bus->dev.of_node)
  85                 return NULL;
  86 
  87         /* Start looking for a phandle to an MSI controller. */
  88         d = of_msi_get_domain(&bus->dev, bus->dev.of_node, DOMAIN_BUS_PCI_MSI);
  89         if (d)
  90                 return d;
  91 
  92         /*
  93          * If we don't have an msi-parent property, look for a domain
  94          * directly attached to the host bridge.
  95          */
  96         d = irq_find_matching_host(bus->dev.of_node, DOMAIN_BUS_PCI_MSI);
  97         if (d)
  98                 return d;
  99 
 100         return irq_find_host(bus->dev.of_node);
 101 #else
 102         return NULL;
 103 #endif
 104 }
 105 
 106 static inline int __of_pci_pci_compare(struct device_node *node,
 107                                        unsigned int data)
 108 {
 109         int devfn;
 110 
 111         devfn = of_pci_get_devfn(node);
 112         if (devfn < 0)
 113                 return 0;
 114 
 115         return devfn == data;
 116 }
 117 
 118 struct device_node *of_pci_find_child_device(struct device_node *parent,
 119                                              unsigned int devfn)
 120 {
 121         struct device_node *node, *node2;
 122 
 123         for_each_child_of_node(parent, node) {
 124                 if (__of_pci_pci_compare(node, devfn))
 125                         return node;
 126                 /*
 127                  * Some OFs create a parent node "multifunc-device" as
 128                  * a fake root for all functions of a multi-function
 129                  * device we go down them as well.
 130                  */
 131                 if (of_node_name_eq(node, "multifunc-device")) {
 132                         for_each_child_of_node(node, node2) {
 133                                 if (__of_pci_pci_compare(node2, devfn)) {
 134                                         of_node_put(node);
 135                                         return node2;
 136                                 }
 137                         }
 138                 }
 139         }
 140         return NULL;
 141 }
 142 EXPORT_SYMBOL_GPL(of_pci_find_child_device);
 143 
 144 /**
 145  * of_pci_get_devfn() - Get device and function numbers for a device node
 146  * @np: device node
 147  *
 148  * Parses a standard 5-cell PCI resource and returns an 8-bit value that can
 149  * be passed to the PCI_SLOT() and PCI_FUNC() macros to extract the device
 150  * and function numbers respectively. On error a negative error code is
 151  * returned.
 152  */
 153 int of_pci_get_devfn(struct device_node *np)
 154 {
 155         u32 reg[5];
 156         int error;
 157 
 158         error = of_property_read_u32_array(np, "reg", reg, ARRAY_SIZE(reg));
 159         if (error)
 160                 return error;
 161 
 162         return (reg[0] >> 8) & 0xff;
 163 }
 164 EXPORT_SYMBOL_GPL(of_pci_get_devfn);
 165 
 166 /**
 167  * of_pci_parse_bus_range() - parse the bus-range property of a PCI device
 168  * @node: device node
 169  * @res: address to a struct resource to return the bus-range
 170  *
 171  * Returns 0 on success or a negative error-code on failure.
 172  */
 173 int of_pci_parse_bus_range(struct device_node *node, struct resource *res)
 174 {
 175         u32 bus_range[2];
 176         int error;
 177 
 178         error = of_property_read_u32_array(node, "bus-range", bus_range,
 179                                            ARRAY_SIZE(bus_range));
 180         if (error)
 181                 return error;
 182 
 183         res->name = node->name;
 184         res->start = bus_range[0];
 185         res->end = bus_range[1];
 186         res->flags = IORESOURCE_BUS;
 187 
 188         return 0;
 189 }
 190 EXPORT_SYMBOL_GPL(of_pci_parse_bus_range);
 191 
 192 /**
 193  * This function will try to obtain the host bridge domain number by
 194  * finding a property called "linux,pci-domain" of the given device node.
 195  *
 196  * @node: device tree node with the domain information
 197  *
 198  * Returns the associated domain number from DT in the range [0-0xffff], or
 199  * a negative value if the required property is not found.
 200  */
 201 int of_get_pci_domain_nr(struct device_node *node)
 202 {
 203         u32 domain;
 204         int error;
 205 
 206         error = of_property_read_u32(node, "linux,pci-domain", &domain);
 207         if (error)
 208                 return error;
 209 
 210         return (u16)domain;
 211 }
 212 EXPORT_SYMBOL_GPL(of_get_pci_domain_nr);
 213 
 214 /**
 215  * of_pci_check_probe_only - Setup probe only mode if linux,pci-probe-only
 216  *                           is present and valid
 217  */
 218 void of_pci_check_probe_only(void)
 219 {
 220         u32 val;
 221         int ret;
 222 
 223         ret = of_property_read_u32(of_chosen, "linux,pci-probe-only", &val);
 224         if (ret) {
 225                 if (ret == -ENODATA || ret == -EOVERFLOW)
 226                         pr_warn("linux,pci-probe-only without valid value, ignoring\n");
 227                 return;
 228         }
 229 
 230         if (val)
 231                 pci_add_flags(PCI_PROBE_ONLY);
 232         else
 233                 pci_clear_flags(PCI_PROBE_ONLY);
 234 
 235         pr_info("PROBE_ONLY %sabled\n", val ? "en" : "dis");
 236 }
 237 EXPORT_SYMBOL_GPL(of_pci_check_probe_only);
 238 
 239 #if defined(CONFIG_OF_ADDRESS)
 240 /**
 241  * devm_of_pci_get_host_bridge_resources() - Resource-managed parsing of PCI
 242  *                                           host bridge resources from DT
 243  * @dev: host bridge device
 244  * @busno: bus number associated with the bridge root bus
 245  * @bus_max: maximum number of buses for this bridge
 246  * @resources: list where the range of resources will be added after DT parsing
 247  * @io_base: pointer to a variable that will contain on return the physical
 248  * address for the start of the I/O range. Can be NULL if the caller doesn't
 249  * expect I/O ranges to be present in the device tree.
 250  *
 251  * This function will parse the "ranges" property of a PCI host bridge device
 252  * node and setup the resource mapping based on its content. It is expected
 253  * that the property conforms with the Power ePAPR document.
 254  *
 255  * It returns zero if the range parsing has been successful or a standard error
 256  * value if it failed.
 257  */
 258 int devm_of_pci_get_host_bridge_resources(struct device *dev,
 259                         unsigned char busno, unsigned char bus_max,
 260                         struct list_head *resources, resource_size_t *io_base)
 261 {
 262         struct device_node *dev_node = dev->of_node;
 263         struct resource *res, tmp_res;
 264         struct resource *bus_range;
 265         struct of_pci_range range;
 266         struct of_pci_range_parser parser;
 267         char range_type[4];
 268         int err;
 269 
 270         if (io_base)
 271                 *io_base = (resource_size_t)OF_BAD_ADDR;
 272 
 273         bus_range = devm_kzalloc(dev, sizeof(*bus_range), GFP_KERNEL);
 274         if (!bus_range)
 275                 return -ENOMEM;
 276 
 277         dev_info(dev, "host bridge %pOF ranges:\n", dev_node);
 278 
 279         err = of_pci_parse_bus_range(dev_node, bus_range);
 280         if (err) {
 281                 bus_range->start = busno;
 282                 bus_range->end = bus_max;
 283                 bus_range->flags = IORESOURCE_BUS;
 284                 dev_info(dev, "  No bus range found for %pOF, using %pR\n",
 285                          dev_node, bus_range);
 286         } else {
 287                 if (bus_range->end > bus_range->start + bus_max)
 288                         bus_range->end = bus_range->start + bus_max;
 289         }
 290         pci_add_resource(resources, bus_range);
 291 
 292         /* Check for ranges property */
 293         err = of_pci_range_parser_init(&parser, dev_node);
 294         if (err)
 295                 goto failed;
 296 
 297         dev_dbg(dev, "Parsing ranges property...\n");
 298         for_each_of_pci_range(&parser, &range) {
 299                 /* Read next ranges element */
 300                 if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_IO)
 301                         snprintf(range_type, 4, " IO");
 302                 else if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_MEM)
 303                         snprintf(range_type, 4, "MEM");
 304                 else
 305                         snprintf(range_type, 4, "err");
 306                 dev_info(dev, "  %s %#010llx..%#010llx -> %#010llx\n",
 307                          range_type, range.cpu_addr,
 308                          range.cpu_addr + range.size - 1, range.pci_addr);
 309 
 310                 /*
 311                  * If we failed translation or got a zero-sized region
 312                  * then skip this range
 313                  */
 314                 if (range.cpu_addr == OF_BAD_ADDR || range.size == 0)
 315                         continue;
 316 
 317                 err = of_pci_range_to_resource(&range, dev_node, &tmp_res);
 318                 if (err)
 319                         continue;
 320 
 321                 res = devm_kmemdup(dev, &tmp_res, sizeof(tmp_res), GFP_KERNEL);
 322                 if (!res) {
 323                         err = -ENOMEM;
 324                         goto failed;
 325                 }
 326 
 327                 if (resource_type(res) == IORESOURCE_IO) {
 328                         if (!io_base) {
 329                                 dev_err(dev, "I/O range found for %pOF. Please provide an io_base pointer to save CPU base address\n",
 330                                         dev_node);
 331                                 err = -EINVAL;
 332                                 goto failed;
 333                         }
 334                         if (*io_base != (resource_size_t)OF_BAD_ADDR)
 335                                 dev_warn(dev, "More than one I/O resource converted for %pOF. CPU base address for old range lost!\n",
 336                                          dev_node);
 337                         *io_base = range.cpu_addr;
 338                 }
 339 
 340                 pci_add_resource_offset(resources, res, res->start - range.pci_addr);
 341         }
 342 
 343         return 0;
 344 
 345 failed:
 346         pci_free_resource_list(resources);
 347         return err;
 348 }
 349 EXPORT_SYMBOL_GPL(devm_of_pci_get_host_bridge_resources);
 350 #endif /* CONFIG_OF_ADDRESS */
 351 
 352 #if IS_ENABLED(CONFIG_OF_IRQ)
 353 /**
 354  * of_irq_parse_pci - Resolve the interrupt for a PCI device
 355  * @pdev:       the device whose interrupt is to be resolved
 356  * @out_irq:    structure of_phandle_args filled by this function
 357  *
 358  * This function resolves the PCI interrupt for a given PCI device. If a
 359  * device-node exists for a given pci_dev, it will use normal OF tree
 360  * walking. If not, it will implement standard swizzling and walk up the
 361  * PCI tree until an device-node is found, at which point it will finish
 362  * resolving using the OF tree walking.
 363  */
 364 static int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
 365 {
 366         struct device_node *dn, *ppnode;
 367         struct pci_dev *ppdev;
 368         __be32 laddr[3];
 369         u8 pin;
 370         int rc;
 371 
 372         /*
 373          * Check if we have a device node, if yes, fallback to standard
 374          * device tree parsing
 375          */
 376         dn = pci_device_to_OF_node(pdev);
 377         if (dn) {
 378                 rc = of_irq_parse_one(dn, 0, out_irq);
 379                 if (!rc)
 380                         return rc;
 381         }
 382 
 383         /*
 384          * Ok, we don't, time to have fun. Let's start by building up an
 385          * interrupt spec.  we assume #interrupt-cells is 1, which is standard
 386          * for PCI. If you do different, then don't use that routine.
 387          */
 388         rc = pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pin);
 389         if (rc != 0)
 390                 goto err;
 391         /* No pin, exit with no error message. */
 392         if (pin == 0)
 393                 return -ENODEV;
 394 
 395         /* Now we walk up the PCI tree */
 396         for (;;) {
 397                 /* Get the pci_dev of our parent */
 398                 ppdev = pdev->bus->self;
 399 
 400                 /* Ouch, it's a host bridge... */
 401                 if (ppdev == NULL) {
 402                         ppnode = pci_bus_to_OF_node(pdev->bus);
 403 
 404                         /* No node for host bridge ? give up */
 405                         if (ppnode == NULL) {
 406                                 rc = -EINVAL;
 407                                 goto err;
 408                         }
 409                 } else {
 410                         /* We found a P2P bridge, check if it has a node */
 411                         ppnode = pci_device_to_OF_node(ppdev);
 412                 }
 413 
 414                 /*
 415                  * Ok, we have found a parent with a device-node, hand over to
 416                  * the OF parsing code.
 417                  * We build a unit address from the linux device to be used for
 418                  * resolution. Note that we use the linux bus number which may
 419                  * not match your firmware bus numbering.
 420                  * Fortunately, in most cases, interrupt-map-mask doesn't
 421                  * include the bus number as part of the matching.
 422                  * You should still be careful about that though if you intend
 423                  * to rely on this function (you ship a firmware that doesn't
 424                  * create device nodes for all PCI devices).
 425                  */
 426                 if (ppnode)
 427                         break;
 428 
 429                 /*
 430                  * We can only get here if we hit a P2P bridge with no node;
 431                  * let's do standard swizzling and try again
 432                  */
 433                 pin = pci_swizzle_interrupt_pin(pdev, pin);
 434                 pdev = ppdev;
 435         }
 436 
 437         out_irq->np = ppnode;
 438         out_irq->args_count = 1;
 439         out_irq->args[0] = pin;
 440         laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8));
 441         laddr[1] = laddr[2] = cpu_to_be32(0);
 442         rc = of_irq_parse_raw(laddr, out_irq);
 443         if (rc)
 444                 goto err;
 445         return 0;
 446 err:
 447         if (rc == -ENOENT) {
 448                 dev_warn(&pdev->dev,
 449                         "%s: no interrupt-map found, INTx interrupts not available\n",
 450                         __func__);
 451                 pr_warn_once("%s: possibly some PCI slots don't have level triggered interrupts capability\n",
 452                         __func__);
 453         } else {
 454                 dev_err(&pdev->dev, "%s: failed with rc=%d\n", __func__, rc);
 455         }
 456         return rc;
 457 }
 458 
 459 /**
 460  * of_irq_parse_and_map_pci() - Decode a PCI IRQ from the device tree and map to a VIRQ
 461  * @dev: The PCI device needing an IRQ
 462  * @slot: PCI slot number; passed when used as map_irq callback. Unused
 463  * @pin: PCI IRQ pin number; passed when used as map_irq callback. Unused
 464  *
 465  * @slot and @pin are unused, but included in the function so that this
 466  * function can be used directly as the map_irq callback to
 467  * pci_assign_irq() and struct pci_host_bridge.map_irq pointer
 468  */
 469 int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin)
 470 {
 471         struct of_phandle_args oirq;
 472         int ret;
 473 
 474         ret = of_irq_parse_pci(dev, &oirq);
 475         if (ret)
 476                 return 0; /* Proper return code 0 == NO_IRQ */
 477 
 478         return irq_create_of_mapping(&oirq);
 479 }
 480 EXPORT_SYMBOL_GPL(of_irq_parse_and_map_pci);
 481 #endif  /* CONFIG_OF_IRQ */
 482 
 483 int pci_parse_request_of_pci_ranges(struct device *dev,
 484                                     struct list_head *resources,
 485                                     struct resource **bus_range)
 486 {
 487         int err, res_valid = 0;
 488         resource_size_t iobase;
 489         struct resource_entry *win, *tmp;
 490 
 491         INIT_LIST_HEAD(resources);
 492         err = devm_of_pci_get_host_bridge_resources(dev, 0, 0xff, resources,
 493                                                     &iobase);
 494         if (err)
 495                 return err;
 496 
 497         err = devm_request_pci_bus_resources(dev, resources);
 498         if (err)
 499                 goto out_release_res;
 500 
 501         resource_list_for_each_entry_safe(win, tmp, resources) {
 502                 struct resource *res = win->res;
 503 
 504                 switch (resource_type(res)) {
 505                 case IORESOURCE_IO:
 506                         err = devm_pci_remap_iospace(dev, res, iobase);
 507                         if (err) {
 508                                 dev_warn(dev, "error %d: failed to map resource %pR\n",
 509                                          err, res);
 510                                 resource_list_destroy_entry(win);
 511                         }
 512                         break;
 513                 case IORESOURCE_MEM:
 514                         res_valid |= !(res->flags & IORESOURCE_PREFETCH);
 515                         break;
 516                 case IORESOURCE_BUS:
 517                         if (bus_range)
 518                                 *bus_range = res;
 519                         break;
 520                 }
 521         }
 522 
 523         if (res_valid)
 524                 return 0;
 525 
 526         dev_err(dev, "non-prefetchable memory resource required\n");
 527         err = -EINVAL;
 528 
 529  out_release_res:
 530         pci_free_resource_list(resources);
 531         return err;
 532 }
 533 
 534 #endif /* CONFIG_PCI */
 535 
 536 /**
 537  * This function will try to find the limitation of link speed by finding
 538  * a property called "max-link-speed" of the given device node.
 539  *
 540  * @node: device tree node with the max link speed information
 541  *
 542  * Returns the associated max link speed from DT, or a negative value if the
 543  * required property is not found or is invalid.
 544  */
 545 int of_pci_get_max_link_speed(struct device_node *node)
 546 {
 547         u32 max_link_speed;
 548 
 549         if (of_property_read_u32(node, "max-link-speed", &max_link_speed) ||
 550             max_link_speed > 4)
 551                 return -EINVAL;
 552 
 553         return max_link_speed;
 554 }
 555 EXPORT_SYMBOL_GPL(of_pci_get_max_link_speed);