drivers/pci/of.c

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