xref: /openbmc/linux/drivers/pci/of.c (revision 7fde9d6e)
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->external_facing = 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  bool pci_host_of_has_msi_map(struct device *dev)
107  {
108  	if (dev && dev->of_node)
109  		return of_get_property(dev->of_node, "msi-map", NULL);
110  	return false;
111  }
112  
113  static inline int __of_pci_pci_compare(struct device_node *node,
114  				       unsigned int data)
115  {
116  	int devfn;
117  
118  	devfn = of_pci_get_devfn(node);
119  	if (devfn < 0)
120  		return 0;
121  
122  	return devfn == data;
123  }
124  
125  struct device_node *of_pci_find_child_device(struct device_node *parent,
126  					     unsigned int devfn)
127  {
128  	struct device_node *node, *node2;
129  
130  	for_each_child_of_node(parent, node) {
131  		if (__of_pci_pci_compare(node, devfn))
132  			return node;
133  		/*
134  		 * Some OFs create a parent node "multifunc-device" as
135  		 * a fake root for all functions of a multi-function
136  		 * device we go down them as well.
137  		 */
138  		if (of_node_name_eq(node, "multifunc-device")) {
139  			for_each_child_of_node(node, node2) {
140  				if (__of_pci_pci_compare(node2, devfn)) {
141  					of_node_put(node);
142  					return node2;
143  				}
144  			}
145  		}
146  	}
147  	return NULL;
148  }
149  EXPORT_SYMBOL_GPL(of_pci_find_child_device);
150  
151  /**
152   * of_pci_get_devfn() - Get device and function numbers for a device node
153   * @np: device node
154   *
155   * Parses a standard 5-cell PCI resource and returns an 8-bit value that can
156   * be passed to the PCI_SLOT() and PCI_FUNC() macros to extract the device
157   * and function numbers respectively. On error a negative error code is
158   * returned.
159   */
160  int of_pci_get_devfn(struct device_node *np)
161  {
162  	u32 reg[5];
163  	int error;
164  
165  	error = of_property_read_u32_array(np, "reg", reg, ARRAY_SIZE(reg));
166  	if (error)
167  		return error;
168  
169  	return (reg[0] >> 8) & 0xff;
170  }
171  EXPORT_SYMBOL_GPL(of_pci_get_devfn);
172  
173  /**
174   * of_pci_parse_bus_range() - parse the bus-range property of a PCI device
175   * @node: device node
176   * @res: address to a struct resource to return the bus-range
177   *
178   * Returns 0 on success or a negative error-code on failure.
179   */
180  int of_pci_parse_bus_range(struct device_node *node, struct resource *res)
181  {
182  	u32 bus_range[2];
183  	int error;
184  
185  	error = of_property_read_u32_array(node, "bus-range", bus_range,
186  					   ARRAY_SIZE(bus_range));
187  	if (error)
188  		return error;
189  
190  	res->name = node->name;
191  	res->start = bus_range[0];
192  	res->end = bus_range[1];
193  	res->flags = IORESOURCE_BUS;
194  
195  	return 0;
196  }
197  EXPORT_SYMBOL_GPL(of_pci_parse_bus_range);
198  
199  /**
200   * of_get_pci_domain_nr - Find the host bridge domain number
201   *			  of the given device node.
202   * @node: Device tree node with the domain information.
203   *
204   * This function will try to obtain the host bridge domain number by finding
205   * a property called "linux,pci-domain" of the given device node.
206   *
207   * Return:
208   * * > 0	- On success, an associated domain number.
209   * * -EINVAL	- The property "linux,pci-domain" does not exist.
210   * * -ENODATA	- The linux,pci-domain" property does not have value.
211   * * -EOVERFLOW	- Invalid "linux,pci-domain" property value.
212   *
213   * Returns the associated domain number from DT in the range [0-0xffff], or
214   * a negative value if the required property is not found.
215   */
216  int of_get_pci_domain_nr(struct device_node *node)
217  {
218  	u32 domain;
219  	int error;
220  
221  	error = of_property_read_u32(node, "linux,pci-domain", &domain);
222  	if (error)
223  		return error;
224  
225  	return (u16)domain;
226  }
227  EXPORT_SYMBOL_GPL(of_get_pci_domain_nr);
228  
229  /**
230   * of_pci_check_probe_only - Setup probe only mode if linux,pci-probe-only
231   *                           is present and valid
232   */
233  void of_pci_check_probe_only(void)
234  {
235  	u32 val;
236  	int ret;
237  
238  	ret = of_property_read_u32(of_chosen, "linux,pci-probe-only", &val);
239  	if (ret) {
240  		if (ret == -ENODATA || ret == -EOVERFLOW)
241  			pr_warn("linux,pci-probe-only without valid value, ignoring\n");
242  		return;
243  	}
244  
245  	if (val)
246  		pci_add_flags(PCI_PROBE_ONLY);
247  	else
248  		pci_clear_flags(PCI_PROBE_ONLY);
249  
250  	pr_info("PROBE_ONLY %sabled\n", val ? "en" : "dis");
251  }
252  EXPORT_SYMBOL_GPL(of_pci_check_probe_only);
253  
254  /**
255   * devm_of_pci_get_host_bridge_resources() - Resource-managed parsing of PCI
256   *                                           host bridge resources from DT
257   * @dev: host bridge device
258   * @busno: bus number associated with the bridge root bus
259   * @bus_max: maximum number of buses for this bridge
260   * @resources: list where the range of resources will be added after DT parsing
261   * @ib_resources: list where the range of inbound resources (with addresses
262   *                from 'dma-ranges') will be added after DT parsing
263   * @io_base: pointer to a variable that will contain on return the physical
264   * address for the start of the I/O range. Can be NULL if the caller doesn't
265   * expect I/O ranges to be present in the device tree.
266   *
267   * This function will parse the "ranges" property of a PCI host bridge device
268   * node and setup the resource mapping based on its content. It is expected
269   * that the property conforms with the Power ePAPR document.
270   *
271   * It returns zero if the range parsing has been successful or a standard error
272   * value if it failed.
273   */
274  static int devm_of_pci_get_host_bridge_resources(struct device *dev,
275  			unsigned char busno, unsigned char bus_max,
276  			struct list_head *resources,
277  			struct list_head *ib_resources,
278  			resource_size_t *io_base)
279  {
280  	struct device_node *dev_node = dev->of_node;
281  	struct resource *res, tmp_res;
282  	struct resource *bus_range;
283  	struct of_pci_range range;
284  	struct of_pci_range_parser parser;
285  	const char *range_type;
286  	int err;
287  
288  	if (io_base)
289  		*io_base = (resource_size_t)OF_BAD_ADDR;
290  
291  	bus_range = devm_kzalloc(dev, sizeof(*bus_range), GFP_KERNEL);
292  	if (!bus_range)
293  		return -ENOMEM;
294  
295  	dev_info(dev, "host bridge %pOF ranges:\n", dev_node);
296  
297  	err = of_pci_parse_bus_range(dev_node, bus_range);
298  	if (err) {
299  		bus_range->start = busno;
300  		bus_range->end = bus_max;
301  		bus_range->flags = IORESOURCE_BUS;
302  		dev_info(dev, "  No bus range found for %pOF, using %pR\n",
303  			 dev_node, bus_range);
304  	} else {
305  		if (bus_range->end > bus_range->start + bus_max)
306  			bus_range->end = bus_range->start + bus_max;
307  	}
308  	pci_add_resource(resources, bus_range);
309  
310  	/* Check for ranges property */
311  	err = of_pci_range_parser_init(&parser, dev_node);
312  	if (err)
313  		goto failed;
314  
315  	dev_dbg(dev, "Parsing ranges property...\n");
316  	for_each_of_pci_range(&parser, &range) {
317  		/* Read next ranges element */
318  		if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_IO)
319  			range_type = "IO";
320  		else if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_MEM)
321  			range_type = "MEM";
322  		else
323  			range_type = "err";
324  		dev_info(dev, "  %6s %#012llx..%#012llx -> %#012llx\n",
325  			 range_type, range.cpu_addr,
326  			 range.cpu_addr + range.size - 1, range.pci_addr);
327  
328  		/*
329  		 * If we failed translation or got a zero-sized region
330  		 * then skip this range
331  		 */
332  		if (range.cpu_addr == OF_BAD_ADDR || range.size == 0)
333  			continue;
334  
335  		err = of_pci_range_to_resource(&range, dev_node, &tmp_res);
336  		if (err)
337  			continue;
338  
339  		res = devm_kmemdup(dev, &tmp_res, sizeof(tmp_res), GFP_KERNEL);
340  		if (!res) {
341  			err = -ENOMEM;
342  			goto failed;
343  		}
344  
345  		if (resource_type(res) == IORESOURCE_IO) {
346  			if (!io_base) {
347  				dev_err(dev, "I/O range found for %pOF. Please provide an io_base pointer to save CPU base address\n",
348  					dev_node);
349  				err = -EINVAL;
350  				goto failed;
351  			}
352  			if (*io_base != (resource_size_t)OF_BAD_ADDR)
353  				dev_warn(dev, "More than one I/O resource converted for %pOF. CPU base address for old range lost!\n",
354  					 dev_node);
355  			*io_base = range.cpu_addr;
356  		} else if (resource_type(res) == IORESOURCE_MEM) {
357  			res->flags &= ~IORESOURCE_MEM_64;
358  		}
359  
360  		pci_add_resource_offset(resources, res,	res->start - range.pci_addr);
361  	}
362  
363  	/* Check for dma-ranges property */
364  	if (!ib_resources)
365  		return 0;
366  	err = of_pci_dma_range_parser_init(&parser, dev_node);
367  	if (err)
368  		return 0;
369  
370  	dev_dbg(dev, "Parsing dma-ranges property...\n");
371  	for_each_of_pci_range(&parser, &range) {
372  		struct resource_entry *entry;
373  		/*
374  		 * If we failed translation or got a zero-sized region
375  		 * then skip this range
376  		 */
377  		if (((range.flags & IORESOURCE_TYPE_BITS) != IORESOURCE_MEM) ||
378  		    range.cpu_addr == OF_BAD_ADDR || range.size == 0)
379  			continue;
380  
381  		dev_info(dev, "  %6s %#012llx..%#012llx -> %#012llx\n",
382  			 "IB MEM", range.cpu_addr,
383  			 range.cpu_addr + range.size - 1, range.pci_addr);
384  
385  
386  		err = of_pci_range_to_resource(&range, dev_node, &tmp_res);
387  		if (err)
388  			continue;
389  
390  		res = devm_kmemdup(dev, &tmp_res, sizeof(tmp_res), GFP_KERNEL);
391  		if (!res) {
392  			err = -ENOMEM;
393  			goto failed;
394  		}
395  
396  		/* Keep the resource list sorted */
397  		resource_list_for_each_entry(entry, ib_resources)
398  			if (entry->res->start > res->start)
399  				break;
400  
401  		pci_add_resource_offset(&entry->node, res,
402  					res->start - range.pci_addr);
403  	}
404  
405  	return 0;
406  
407  failed:
408  	pci_free_resource_list(resources);
409  	return err;
410  }
411  
412  #if IS_ENABLED(CONFIG_OF_IRQ)
413  /**
414   * of_irq_parse_pci - Resolve the interrupt for a PCI device
415   * @pdev:       the device whose interrupt is to be resolved
416   * @out_irq:    structure of_phandle_args filled by this function
417   *
418   * This function resolves the PCI interrupt for a given PCI device. If a
419   * device-node exists for a given pci_dev, it will use normal OF tree
420   * walking. If not, it will implement standard swizzling and walk up the
421   * PCI tree until an device-node is found, at which point it will finish
422   * resolving using the OF tree walking.
423   */
424  static int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
425  {
426  	struct device_node *dn, *ppnode;
427  	struct pci_dev *ppdev;
428  	__be32 laddr[3];
429  	u8 pin;
430  	int rc;
431  
432  	/*
433  	 * Check if we have a device node, if yes, fallback to standard
434  	 * device tree parsing
435  	 */
436  	dn = pci_device_to_OF_node(pdev);
437  	if (dn) {
438  		rc = of_irq_parse_one(dn, 0, out_irq);
439  		if (!rc)
440  			return rc;
441  	}
442  
443  	/*
444  	 * Ok, we don't, time to have fun. Let's start by building up an
445  	 * interrupt spec.  we assume #interrupt-cells is 1, which is standard
446  	 * for PCI. If you do different, then don't use that routine.
447  	 */
448  	rc = pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pin);
449  	if (rc != 0)
450  		goto err;
451  	/* No pin, exit with no error message. */
452  	if (pin == 0)
453  		return -ENODEV;
454  
455  	/* Now we walk up the PCI tree */
456  	for (;;) {
457  		/* Get the pci_dev of our parent */
458  		ppdev = pdev->bus->self;
459  
460  		/* Ouch, it's a host bridge... */
461  		if (ppdev == NULL) {
462  			ppnode = pci_bus_to_OF_node(pdev->bus);
463  
464  			/* No node for host bridge ? give up */
465  			if (ppnode == NULL) {
466  				rc = -EINVAL;
467  				goto err;
468  			}
469  		} else {
470  			/* We found a P2P bridge, check if it has a node */
471  			ppnode = pci_device_to_OF_node(ppdev);
472  		}
473  
474  		/*
475  		 * Ok, we have found a parent with a device-node, hand over to
476  		 * the OF parsing code.
477  		 * We build a unit address from the linux device to be used for
478  		 * resolution. Note that we use the linux bus number which may
479  		 * not match your firmware bus numbering.
480  		 * Fortunately, in most cases, interrupt-map-mask doesn't
481  		 * include the bus number as part of the matching.
482  		 * You should still be careful about that though if you intend
483  		 * to rely on this function (you ship a firmware that doesn't
484  		 * create device nodes for all PCI devices).
485  		 */
486  		if (ppnode)
487  			break;
488  
489  		/*
490  		 * We can only get here if we hit a P2P bridge with no node;
491  		 * let's do standard swizzling and try again
492  		 */
493  		pin = pci_swizzle_interrupt_pin(pdev, pin);
494  		pdev = ppdev;
495  	}
496  
497  	out_irq->np = ppnode;
498  	out_irq->args_count = 1;
499  	out_irq->args[0] = pin;
500  	laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8));
501  	laddr[1] = laddr[2] = cpu_to_be32(0);
502  	rc = of_irq_parse_raw(laddr, out_irq);
503  	if (rc)
504  		goto err;
505  	return 0;
506  err:
507  	if (rc == -ENOENT) {
508  		dev_warn(&pdev->dev,
509  			"%s: no interrupt-map found, INTx interrupts not available\n",
510  			__func__);
511  		pr_warn_once("%s: possibly some PCI slots don't have level triggered interrupts capability\n",
512  			__func__);
513  	} else {
514  		dev_err(&pdev->dev, "%s: failed with rc=%d\n", __func__, rc);
515  	}
516  	return rc;
517  }
518  
519  /**
520   * of_irq_parse_and_map_pci() - Decode a PCI IRQ from the device tree and map to a VIRQ
521   * @dev: The PCI device needing an IRQ
522   * @slot: PCI slot number; passed when used as map_irq callback. Unused
523   * @pin: PCI IRQ pin number; passed when used as map_irq callback. Unused
524   *
525   * @slot and @pin are unused, but included in the function so that this
526   * function can be used directly as the map_irq callback to
527   * pci_assign_irq() and struct pci_host_bridge.map_irq pointer
528   */
529  int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin)
530  {
531  	struct of_phandle_args oirq;
532  	int ret;
533  
534  	ret = of_irq_parse_pci(dev, &oirq);
535  	if (ret)
536  		return 0; /* Proper return code 0 == NO_IRQ */
537  
538  	return irq_create_of_mapping(&oirq);
539  }
540  EXPORT_SYMBOL_GPL(of_irq_parse_and_map_pci);
541  #endif	/* CONFIG_OF_IRQ */
542  
543  static int pci_parse_request_of_pci_ranges(struct device *dev,
544  					   struct pci_host_bridge *bridge)
545  {
546  	int err, res_valid = 0;
547  	resource_size_t iobase;
548  	struct resource_entry *win, *tmp;
549  
550  	INIT_LIST_HEAD(&bridge->windows);
551  	INIT_LIST_HEAD(&bridge->dma_ranges);
552  
553  	err = devm_of_pci_get_host_bridge_resources(dev, 0, 0xff, &bridge->windows,
554  						    &bridge->dma_ranges, &iobase);
555  	if (err)
556  		return err;
557  
558  	err = devm_request_pci_bus_resources(dev, &bridge->windows);
559  	if (err)
560  		return err;
561  
562  	resource_list_for_each_entry_safe(win, tmp, &bridge->windows) {
563  		struct resource *res = win->res;
564  
565  		switch (resource_type(res)) {
566  		case IORESOURCE_IO:
567  			err = devm_pci_remap_iospace(dev, res, iobase);
568  			if (err) {
569  				dev_warn(dev, "error %d: failed to map resource %pR\n",
570  					 err, res);
571  				resource_list_destroy_entry(win);
572  			}
573  			break;
574  		case IORESOURCE_MEM:
575  			res_valid |= !(res->flags & IORESOURCE_PREFETCH);
576  
577  			if (!(res->flags & IORESOURCE_PREFETCH))
578  				if (upper_32_bits(resource_size(res)))
579  					dev_warn(dev, "Memory resource size exceeds max for 32 bits\n");
580  
581  			break;
582  		}
583  	}
584  
585  	if (!res_valid)
586  		dev_warn(dev, "non-prefetchable memory resource required\n");
587  
588  	return 0;
589  }
590  
591  int devm_of_pci_bridge_init(struct device *dev, struct pci_host_bridge *bridge)
592  {
593  	if (!dev->of_node)
594  		return 0;
595  
596  	bridge->swizzle_irq = pci_common_swizzle;
597  	bridge->map_irq = of_irq_parse_and_map_pci;
598  
599  	return pci_parse_request_of_pci_ranges(dev, bridge);
600  }
601  
602  #endif /* CONFIG_PCI */
603  
604  /**
605   * of_pci_get_max_link_speed - Find the maximum link speed of the given device node.
606   * @node: Device tree node with the maximum link speed information.
607   *
608   * This function will try to find the limitation of link speed by finding
609   * a property called "max-link-speed" of the given device node.
610   *
611   * Return:
612   * * > 0	- On success, a maximum link speed.
613   * * -EINVAL	- Invalid "max-link-speed" property value, or failure to access
614   *		  the property of the device tree node.
615   *
616   * Returns the associated max link speed from DT, or a negative value if the
617   * required property is not found or is invalid.
618   */
619  int of_pci_get_max_link_speed(struct device_node *node)
620  {
621  	u32 max_link_speed;
622  
623  	if (of_property_read_u32(node, "max-link-speed", &max_link_speed) ||
624  	    max_link_speed == 0 || max_link_speed > 4)
625  		return -EINVAL;
626  
627  	return max_link_speed;
628  }
629  EXPORT_SYMBOL_GPL(of_pci_get_max_link_speed);
630