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