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/cleanup.h>
 10#include <linux/irqdomain.h>
 11#include <linux/kernel.h>
 12#include <linux/pci.h>
 13#include <linux/of.h>
 14#include <linux/of_irq.h>
 15#include <linux/of_address.h>
 16#include <linux/of_pci.h>
 17#include <linux/platform_device.h>
 18#include "pci.h"
 19
 20#ifdef CONFIG_PCI
 21/**
 22 * pci_set_of_node - Find and set device's DT device_node
 23 * @dev: the PCI device structure to fill
 24 *
 25 * Returns 0 on success with of_node set or when no device is described in the
 26 * DT. Returns -ENODEV if the device is present, but disabled in the DT.
 27 */
 28int pci_set_of_node(struct pci_dev *dev)
 29{
 30	if (!dev->bus->dev.of_node)
 31		return 0;
 32
 33	struct device_node *node __free(device_node) =
 34		of_pci_find_child_device(dev->bus->dev.of_node, dev->devfn);
 35	if (!node)
 36		return 0;
 37
 38	struct device *pdev __free(put_device) =
 39		bus_find_device_by_of_node(&platform_bus_type, node);
 40	if (pdev)
 41		dev->bus->dev.of_node_reused = true;
 42
 43	device_set_node(&dev->dev, of_fwnode_handle(no_free_ptr(node)));
 44	return 0;
 45}
 46
 47void pci_release_of_node(struct pci_dev *dev)
 48{
 49	of_node_put(dev->dev.of_node);
 50	device_set_node(&dev->dev, NULL);
 51}
 52
 53void pci_set_bus_of_node(struct pci_bus *bus)
 54{
 55	struct device_node *node;
 56
 57	if (bus->self == NULL) {
 58		node = pcibios_get_phb_of_node(bus);
 59	} else {
 60		node = of_node_get(bus->self->dev.of_node);
 61		if (node && of_property_read_bool(node, "external-facing"))
 62			bus->self->external_facing = true;
 63	}
 64
 65	device_set_node(&bus->dev, of_fwnode_handle(node));
 66}
 67
 68void pci_release_bus_of_node(struct pci_bus *bus)
 69{
 70	of_node_put(bus->dev.of_node);
 71	device_set_node(&bus->dev, NULL);
 72}
 73
 74struct device_node * __weak pcibios_get_phb_of_node(struct pci_bus *bus)
 75{
 76	/* This should only be called for PHBs */
 77	if (WARN_ON(bus->self || bus->parent))
 78		return NULL;
 79
 80	/*
 81	 * Look for a node pointer in either the intermediary device we
 82	 * create above the root bus or its own parent. Normally only
 83	 * the later is populated.
 84	 */
 85	if (bus->bridge->of_node)
 86		return of_node_get(bus->bridge->of_node);
 87	if (bus->bridge->parent && bus->bridge->parent->of_node)
 88		return of_node_get(bus->bridge->parent->of_node);
 89	return NULL;
 90}
 91
 92struct irq_domain *pci_host_bridge_of_msi_domain(struct pci_bus *bus)
 93{
 94#ifdef CONFIG_IRQ_DOMAIN
 95	struct irq_domain *d;
 96
 97	if (!bus->dev.of_node)
 98		return NULL;
 99
100	/* Start looking for a phandle to an MSI controller. */
101	d = of_msi_get_domain(&bus->dev, bus->dev.of_node, DOMAIN_BUS_PCI_MSI);
102	if (d)
103		return d;
104
105	/*
106	 * If we don't have an msi-parent property, look for a domain
107	 * directly attached to the host bridge.
108	 */
109	d = irq_find_matching_host(bus->dev.of_node, DOMAIN_BUS_PCI_MSI);
110	if (d)
111		return d;
112
113	return irq_find_host(bus->dev.of_node);
114#else
115	return NULL;
116#endif
117}
118
119bool pci_host_of_has_msi_map(struct device *dev)
120{
121	if (dev && dev->of_node)
122		return of_get_property(dev->of_node, "msi-map", NULL);
123	return false;
124}
125
126static inline int __of_pci_pci_compare(struct device_node *node,
127				       unsigned int data)
128{
129	int devfn;
130
131	devfn = of_pci_get_devfn(node);
132	if (devfn < 0)
133		return 0;
134
135	return devfn == data;
136}
137
138struct device_node *of_pci_find_child_device(struct device_node *parent,
139					     unsigned int devfn)
140{
141	struct device_node *node, *node2;
142
143	for_each_child_of_node(parent, node) {
144		if (__of_pci_pci_compare(node, devfn))
145			return node;
146		/*
147		 * Some OFs create a parent node "multifunc-device" as
148		 * a fake root for all functions of a multi-function
149		 * device we go down them as well.
150		 */
151		if (of_node_name_eq(node, "multifunc-device")) {
152			for_each_child_of_node(node, node2) {
153				if (__of_pci_pci_compare(node2, devfn)) {
154					of_node_put(node);
155					return node2;
156				}
157			}
158		}
159	}
160	return NULL;
161}
162EXPORT_SYMBOL_GPL(of_pci_find_child_device);
163
164/**
165 * of_pci_get_devfn() - Get device and function numbers for a device node
166 * @np: device node
167 *
168 * Parses a standard 5-cell PCI resource and returns an 8-bit value that can
169 * be passed to the PCI_SLOT() and PCI_FUNC() macros to extract the device
170 * and function numbers respectively. On error a negative error code is
171 * returned.
172 */
173int of_pci_get_devfn(struct device_node *np)
174{
175	u32 reg[5];
176	int error;
177
178	error = of_property_read_u32_array(np, "reg", reg, ARRAY_SIZE(reg));
179	if (error)
180		return error;
181
182	return (reg[0] >> 8) & 0xff;
183}
184EXPORT_SYMBOL_GPL(of_pci_get_devfn);
185
186/**
187 * of_pci_parse_bus_range() - parse the bus-range property of a PCI device
188 * @node: device node
189 * @res: address to a struct resource to return the bus-range
190 *
191 * Returns 0 on success or a negative error-code on failure.
192 */
193int of_pci_parse_bus_range(struct device_node *node, struct resource *res)
194{
195	u32 bus_range[2];
196	int error;
197
198	error = of_property_read_u32_array(node, "bus-range", bus_range,
199					   ARRAY_SIZE(bus_range));
200	if (error)
201		return error;
202
203	res->name = node->name;
204	res->start = bus_range[0];
205	res->end = bus_range[1];
206	res->flags = IORESOURCE_BUS;
207
208	return 0;
209}
210EXPORT_SYMBOL_GPL(of_pci_parse_bus_range);
211
212/**
213 * of_get_pci_domain_nr - Find the host bridge domain number
214 *			  of the given device node.
215 * @node: Device tree node with the domain information.
216 *
217 * This function will try to obtain the host bridge domain number by finding
218 * a property called "linux,pci-domain" of the given device node.
219 *
220 * Return:
221 * * > 0	- On success, an associated domain number.
222 * * -EINVAL	- The property "linux,pci-domain" does not exist.
223 * * -ENODATA	- The linux,pci-domain" property does not have value.
224 * * -EOVERFLOW	- Invalid "linux,pci-domain" property value.
225 *
226 * Returns the associated domain number from DT in the range [0-0xffff], or
227 * a negative value if the required property is not found.
228 */
229int of_get_pci_domain_nr(struct device_node *node)
230{
231	u32 domain;
232	int error;
233
234	error = of_property_read_u32(node, "linux,pci-domain", &domain);
235	if (error)
236		return error;
237
238	return (u16)domain;
239}
240EXPORT_SYMBOL_GPL(of_get_pci_domain_nr);
241
242/**
243 * of_pci_preserve_config - Return true if the boot configuration needs to
244 *                          be preserved
245 * @node: Device tree node.
246 *
247 * Look for "linux,pci-probe-only" property for a given PCI controller's
248 * node and return true if found. Also look in the chosen node if the
249 * property is not found in the given controller's node.  Having this
250 * property ensures that the kernel doesn't reconfigure the BARs and bridge
251 * windows that are already done by the platform firmware.
252 *
253 * Return: true if the property exists; false otherwise.
254 */
255bool of_pci_preserve_config(struct device_node *node)
256{
257	u32 val = 0;
258	int ret;
259
260	if (!node) {
261		pr_warn("device node is NULL, trying with of_chosen\n");
262		node = of_chosen;
263	}
264
265retry:
266	ret = of_property_read_u32(node, "linux,pci-probe-only", &val);
267	if (ret) {
268		if (ret == -ENODATA || ret == -EOVERFLOW) {
269			pr_warn("Incorrect value for linux,pci-probe-only in %pOF, ignoring\n",
270				node);
271			return false;
272		}
273		if (ret == -EINVAL) {
274			if (node == of_chosen)
275				return false;
276
277			node = of_chosen;
278			goto retry;
279		}
280	}
281
282	if (val)
283		return true;
284	else
285		return false;
286}
287
288/**
289 * of_pci_check_probe_only - Setup probe only mode if linux,pci-probe-only
290 *                           is present and valid
291 */
292void of_pci_check_probe_only(void)
293{
294	if (of_pci_preserve_config(of_chosen))
295		pci_add_flags(PCI_PROBE_ONLY);
296	else
297		pci_clear_flags(PCI_PROBE_ONLY);
298}
299EXPORT_SYMBOL_GPL(of_pci_check_probe_only);
300
301/**
302 * devm_of_pci_get_host_bridge_resources() - Resource-managed parsing of PCI
303 *                                           host bridge resources from DT
304 * @dev: host bridge device
305 * @busno: bus number associated with the bridge root bus
306 * @bus_max: maximum number of buses for this bridge
307 * @resources: list where the range of resources will be added after DT parsing
308 * @ib_resources: list where the range of inbound resources (with addresses
309 *                from 'dma-ranges') will be added after DT parsing
310 * @io_base: pointer to a variable that will contain on return the physical
311 * address for the start of the I/O range. Can be NULL if the caller doesn't
312 * expect I/O ranges to be present in the device tree.
313 *
314 * This function will parse the "ranges" property of a PCI host bridge device
315 * node and setup the resource mapping based on its content. It is expected
316 * that the property conforms with the Power ePAPR document.
317 *
318 * It returns zero if the range parsing has been successful or a standard error
319 * value if it failed.
320 */
321static int devm_of_pci_get_host_bridge_resources(struct device *dev,
322			unsigned char busno, unsigned char bus_max,
323			struct list_head *resources,
324			struct list_head *ib_resources,
325			resource_size_t *io_base)
326{
327	struct device_node *dev_node = dev->of_node;
328	struct resource *res, tmp_res;
329	struct resource *bus_range;
330	struct of_pci_range range;
331	struct of_pci_range_parser parser;
332	const char *range_type;
333	int err;
334
335	if (io_base)
336		*io_base = (resource_size_t)OF_BAD_ADDR;
337
338	bus_range = devm_kzalloc(dev, sizeof(*bus_range), GFP_KERNEL);
339	if (!bus_range)
340		return -ENOMEM;
341
342	dev_info(dev, "host bridge %pOF ranges:\n", dev_node);
343
344	err = of_pci_parse_bus_range(dev_node, bus_range);
345	if (err) {
346		bus_range->start = busno;
347		bus_range->end = bus_max;
348		bus_range->flags = IORESOURCE_BUS;
349		dev_info(dev, "  No bus range found for %pOF, using %pR\n",
350			 dev_node, bus_range);
351	} else {
352		if (bus_range->end > bus_range->start + bus_max)
353			bus_range->end = bus_range->start + bus_max;
354	}
355	pci_add_resource(resources, bus_range);
356
357	/* Check for ranges property */
358	err = of_pci_range_parser_init(&parser, dev_node);
359	if (err)
360		return 0;
361
362	dev_dbg(dev, "Parsing ranges property...\n");
363	for_each_of_pci_range(&parser, &range) {
364		/* Read next ranges element */
365		if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_IO)
366			range_type = "IO";
367		else if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_MEM)
368			range_type = "MEM";
369		else
370			range_type = "err";
371		dev_info(dev, "  %6s %#012llx..%#012llx -> %#012llx\n",
372			 range_type, range.cpu_addr,
373			 range.cpu_addr + range.size - 1, range.pci_addr);
374
375		/*
376		 * If we failed translation or got a zero-sized region
377		 * then skip this range
378		 */
379		if (range.cpu_addr == OF_BAD_ADDR || range.size == 0)
380			continue;
381
382		err = of_pci_range_to_resource(&range, dev_node, &tmp_res);
383		if (err)
384			continue;
385
386		res = devm_kmemdup(dev, &tmp_res, sizeof(tmp_res), GFP_KERNEL);
387		if (!res) {
388			err = -ENOMEM;
389			goto failed;
390		}
391
392		if (resource_type(res) == IORESOURCE_IO) {
393			if (!io_base) {
394				dev_err(dev, "I/O range found for %pOF. Please provide an io_base pointer to save CPU base address\n",
395					dev_node);
396				err = -EINVAL;
397				goto failed;
398			}
399			if (*io_base != (resource_size_t)OF_BAD_ADDR)
400				dev_warn(dev, "More than one I/O resource converted for %pOF. CPU base address for old range lost!\n",
401					 dev_node);
402			*io_base = range.cpu_addr;
403		} else if (resource_type(res) == IORESOURCE_MEM) {
404			res->flags &= ~IORESOURCE_MEM_64;
405		}
406
407		pci_add_resource_offset(resources, res,	res->start - range.pci_addr);
408	}
409
410	/* Check for dma-ranges property */
411	if (!ib_resources)
412		return 0;
413	err = of_pci_dma_range_parser_init(&parser, dev_node);
414	if (err)
415		return 0;
416
417	dev_dbg(dev, "Parsing dma-ranges property...\n");
418	for_each_of_pci_range(&parser, &range) {
419		/*
420		 * If we failed translation or got a zero-sized region
421		 * then skip this range
422		 */
423		if (((range.flags & IORESOURCE_TYPE_BITS) != IORESOURCE_MEM) ||
424		    range.cpu_addr == OF_BAD_ADDR || range.size == 0)
425			continue;
426
427		dev_info(dev, "  %6s %#012llx..%#012llx -> %#012llx\n",
428			 "IB MEM", range.cpu_addr,
429			 range.cpu_addr + range.size - 1, range.pci_addr);
430
431
432		err = of_pci_range_to_resource(&range, dev_node, &tmp_res);
433		if (err)
434			continue;
435
436		res = devm_kmemdup(dev, &tmp_res, sizeof(tmp_res), GFP_KERNEL);
437		if (!res) {
438			err = -ENOMEM;
439			goto failed;
440		}
441
442		pci_add_resource_offset(ib_resources, res,
443					res->start - range.pci_addr);
444	}
445
446	return 0;
447
448failed:
449	pci_free_resource_list(resources);
450	return err;
451}
452
453#if IS_ENABLED(CONFIG_OF_IRQ)
454/**
455 * of_irq_parse_pci - Resolve the interrupt for a PCI device
456 * @pdev:       the device whose interrupt is to be resolved
457 * @out_irq:    structure of_phandle_args filled by this function
458 *
459 * This function resolves the PCI interrupt for a given PCI device. If a
460 * device-node exists for a given pci_dev, it will use normal OF tree
461 * walking. If not, it will implement standard swizzling and walk up the
462 * PCI tree until an device-node is found, at which point it will finish
463 * resolving using the OF tree walking.
464 */
465static int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
466{
467	struct device_node *dn, *ppnode = NULL;
468	struct pci_dev *ppdev;
469	__be32 laddr[3];
470	u8 pin;
471	int rc;
472
473	/*
474	 * Check if we have a device node, if yes, fallback to standard
475	 * device tree parsing
476	 */
477	dn = pci_device_to_OF_node(pdev);
478	if (dn) {
479		rc = of_irq_parse_one(dn, 0, out_irq);
480		if (!rc)
481			return rc;
482	}
483
484	/*
485	 * Ok, we don't, time to have fun. Let's start by building up an
486	 * interrupt spec.  we assume #interrupt-cells is 1, which is standard
487	 * for PCI. If you do different, then don't use that routine.
488	 */
489	rc = pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pin);
490	if (rc != 0)
491		goto err;
492	/* No pin, exit with no error message. */
493	if (pin == 0)
494		return -ENODEV;
495
496	/* Local interrupt-map in the device node? Use it! */
497	if (of_property_present(dn, "interrupt-map")) {
498		pin = pci_swizzle_interrupt_pin(pdev, pin);
499		ppnode = dn;
500	}
501
502	/* Now we walk up the PCI tree */
503	while (!ppnode) {
504		/* Get the pci_dev of our parent */
505		ppdev = pdev->bus->self;
506
507		/* Ouch, it's a host bridge... */
508		if (ppdev == NULL) {
509			ppnode = pci_bus_to_OF_node(pdev->bus);
510
511			/* No node for host bridge ? give up */
512			if (ppnode == NULL) {
513				rc = -EINVAL;
514				goto err;
515			}
516		} else {
517			/* We found a P2P bridge, check if it has a node */
518			ppnode = pci_device_to_OF_node(ppdev);
519		}
520
521		/*
522		 * Ok, we have found a parent with a device-node, hand over to
523		 * the OF parsing code.
524		 * We build a unit address from the linux device to be used for
525		 * resolution. Note that we use the linux bus number which may
526		 * not match your firmware bus numbering.
527		 * Fortunately, in most cases, interrupt-map-mask doesn't
528		 * include the bus number as part of the matching.
529		 * You should still be careful about that though if you intend
530		 * to rely on this function (you ship a firmware that doesn't
531		 * create device nodes for all PCI devices).
532		 */
533		if (ppnode)
534			break;
535
536		/*
537		 * We can only get here if we hit a P2P bridge with no node;
538		 * let's do standard swizzling and try again
539		 */
540		pin = pci_swizzle_interrupt_pin(pdev, pin);
541		pdev = ppdev;
542	}
543
544	out_irq->np = ppnode;
545	out_irq->args_count = 1;
546	out_irq->args[0] = pin;
547	laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8));
548	laddr[1] = laddr[2] = cpu_to_be32(0);
549	rc = of_irq_parse_raw(laddr, out_irq);
550	if (rc)
551		goto err;
552	return 0;
553err:
554	if (rc == -ENOENT) {
555		dev_warn(&pdev->dev,
556			"%s: no interrupt-map found, INTx interrupts not available\n",
557			__func__);
558		pr_warn_once("%s: possibly some PCI slots don't have level triggered interrupts capability\n",
559			__func__);
560	} else {
561		dev_err(&pdev->dev, "%s: failed with rc=%d\n", __func__, rc);
562	}
563	return rc;
564}
565
566/**
567 * of_irq_parse_and_map_pci() - Decode a PCI IRQ from the device tree and map to a VIRQ
568 * @dev: The PCI device needing an IRQ
569 * @slot: PCI slot number; passed when used as map_irq callback. Unused
570 * @pin: PCI IRQ pin number; passed when used as map_irq callback. Unused
571 *
572 * @slot and @pin are unused, but included in the function so that this
573 * function can be used directly as the map_irq callback to
574 * pci_assign_irq() and struct pci_host_bridge.map_irq pointer
575 */
576int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin)
577{
578	struct of_phandle_args oirq;
579	int ret;
580
581	ret = of_irq_parse_pci(dev, &oirq);
582	if (ret)
583		return 0; /* Proper return code 0 == NO_IRQ */
584
585	return irq_create_of_mapping(&oirq);
586}
587EXPORT_SYMBOL_GPL(of_irq_parse_and_map_pci);
588#endif	/* CONFIG_OF_IRQ */
589
590static int pci_parse_request_of_pci_ranges(struct device *dev,
591					   struct pci_host_bridge *bridge)
592{
593	int err, res_valid = 0;
594	resource_size_t iobase;
595	struct resource_entry *win, *tmp;
596
597	INIT_LIST_HEAD(&bridge->windows);
598	INIT_LIST_HEAD(&bridge->dma_ranges);
599
600	err = devm_of_pci_get_host_bridge_resources(dev, 0, 0xff, &bridge->windows,
601						    &bridge->dma_ranges, &iobase);
602	if (err)
603		return err;
604
605	err = devm_request_pci_bus_resources(dev, &bridge->windows);
606	if (err)
607		return err;
608
609	resource_list_for_each_entry_safe(win, tmp, &bridge->windows) {
610		struct resource *res = win->res;
611
612		switch (resource_type(res)) {
613		case IORESOURCE_IO:
614			err = devm_pci_remap_iospace(dev, res, iobase);
615			if (err) {
616				dev_warn(dev, "error %d: failed to map resource %pR\n",
617					 err, res);
618				resource_list_destroy_entry(win);
619			}
620			break;
621		case IORESOURCE_MEM:
622			res_valid |= !(res->flags & IORESOURCE_PREFETCH);
623
624			if (!(res->flags & IORESOURCE_PREFETCH))
625				if (upper_32_bits(resource_size(res)))
626					dev_warn(dev, "Memory resource size exceeds max for 32 bits\n");
627
628			break;
629		}
630	}
631
632	if (!res_valid)
633		dev_warn(dev, "non-prefetchable memory resource required\n");
634
635	return 0;
636}
637
638int devm_of_pci_bridge_init(struct device *dev, struct pci_host_bridge *bridge)
639{
640	if (!dev->of_node)
641		return 0;
642
643	bridge->swizzle_irq = pci_common_swizzle;
644	bridge->map_irq = of_irq_parse_and_map_pci;
645
646	return pci_parse_request_of_pci_ranges(dev, bridge);
647}
648
649#ifdef CONFIG_PCI_DYNAMIC_OF_NODES
650
651void of_pci_remove_node(struct pci_dev *pdev)
652{
653	struct device_node *np;
654
655	np = pci_device_to_OF_node(pdev);
656	if (!np || !of_node_check_flag(np, OF_DYNAMIC))
657		return;
658	pdev->dev.of_node = NULL;
659
660	of_changeset_revert(np->data);
661	of_changeset_destroy(np->data);
662	of_node_put(np);
663}
664
665void of_pci_make_dev_node(struct pci_dev *pdev)
666{
667	struct device_node *ppnode, *np = NULL;
668	const char *pci_type;
669	struct of_changeset *cset;
670	const char *name;
671	int ret;
672
673	/*
674	 * If there is already a device tree node linked to this device,
675	 * return immediately.
676	 */
677	if (pci_device_to_OF_node(pdev))
678		return;
679
680	/* Check if there is device tree node for parent device */
681	if (!pdev->bus->self)
682		ppnode = pdev->bus->dev.of_node;
683	else
684		ppnode = pdev->bus->self->dev.of_node;
685	if (!ppnode)
686		return;
687
688	if (pci_is_bridge(pdev))
689		pci_type = "pci";
690	else
691		pci_type = "dev";
692
693	name = kasprintf(GFP_KERNEL, "%s@%x,%x", pci_type,
694			 PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
695	if (!name)
696		return;
697
698	cset = kmalloc(sizeof(*cset), GFP_KERNEL);
699	if (!cset)
700		goto out_free_name;
701	of_changeset_init(cset);
702
703	np = of_changeset_create_node(cset, ppnode, name);
704	if (!np)
705		goto out_destroy_cset;
706
707	ret = of_pci_add_properties(pdev, cset, np);
708	if (ret)
709		goto out_free_node;
710
711	ret = of_changeset_apply(cset);
712	if (ret)
713		goto out_free_node;
714
715	np->data = cset;
716	pdev->dev.of_node = np;
717	kfree(name);
718
719	return;
720
721out_free_node:
722	of_node_put(np);
723out_destroy_cset:
724	of_changeset_destroy(cset);
725	kfree(cset);
726out_free_name:
727	kfree(name);
728}
729#endif
730
731/**
732 * of_pci_supply_present() - Check if the power supply is present for the PCI
733 *				device
734 * @np: Device tree node
735 *
736 * Check if the power supply for the PCI device is present in the device tree
737 * node or not.
738 *
739 * Return: true if at least one power supply exists; false otherwise.
740 */
741bool of_pci_supply_present(struct device_node *np)
742{
743	struct property *prop;
744	char *supply;
745
746	if (!np)
747		return false;
748
749	for_each_property_of_node(np, prop) {
750		supply = strrchr(prop->name, '-');
751		if (supply && !strcmp(supply, "-supply"))
752			return true;
753	}
754
755	return false;
756}
757
758#endif /* CONFIG_PCI */
759
760/**
761 * of_pci_get_max_link_speed - Find the maximum link speed of the given device node.
762 * @node: Device tree node with the maximum link speed information.
763 *
764 * This function will try to find the limitation of link speed by finding
765 * a property called "max-link-speed" of the given device node.
766 *
767 * Return:
768 * * > 0	- On success, a maximum link speed.
769 * * -EINVAL	- Invalid "max-link-speed" property value, or failure to access
770 *		  the property of the device tree node.
771 *
772 * Returns the associated max link speed from DT, or a negative value if the
773 * required property is not found or is invalid.
774 */
775int of_pci_get_max_link_speed(struct device_node *node)
776{
777	u32 max_link_speed;
778
779	if (of_property_read_u32(node, "max-link-speed", &max_link_speed) ||
780	    max_link_speed == 0 || max_link_speed > 4)
781		return -EINVAL;
782
783	return max_link_speed;
784}
785EXPORT_SYMBOL_GPL(of_pci_get_max_link_speed);
786
787/**
788 * of_pci_get_slot_power_limit - Parses the "slot-power-limit-milliwatt"
789 *				 property.
790 *
791 * @node: device tree node with the slot power limit information
792 * @slot_power_limit_value: pointer where the value should be stored in PCIe
793 *			    Slot Capabilities Register format
794 * @slot_power_limit_scale: pointer where the scale should be stored in PCIe
795 *			    Slot Capabilities Register format
796 *
797 * Returns the slot power limit in milliwatts and if @slot_power_limit_value
798 * and @slot_power_limit_scale pointers are non-NULL, fills in the value and
799 * scale in format used by PCIe Slot Capabilities Register.
800 *
801 * If the property is not found or is invalid, returns 0.
802 */
803u32 of_pci_get_slot_power_limit(struct device_node *node,
804				u8 *slot_power_limit_value,
805				u8 *slot_power_limit_scale)
806{
807	u32 slot_power_limit_mw;
808	u8 value, scale;
809
810	if (of_property_read_u32(node, "slot-power-limit-milliwatt",
811				 &slot_power_limit_mw))
812		slot_power_limit_mw = 0;
813
814	/* Calculate Slot Power Limit Value and Slot Power Limit Scale */
815	if (slot_power_limit_mw == 0) {
816		value = 0x00;
817		scale = 0;
818	} else if (slot_power_limit_mw <= 255) {
819		value = slot_power_limit_mw;
820		scale = 3;
821	} else if (slot_power_limit_mw <= 255*10) {
822		value = slot_power_limit_mw / 10;
823		scale = 2;
824		slot_power_limit_mw = slot_power_limit_mw / 10 * 10;
825	} else if (slot_power_limit_mw <= 255*100) {
826		value = slot_power_limit_mw / 100;
827		scale = 1;
828		slot_power_limit_mw = slot_power_limit_mw / 100 * 100;
829	} else if (slot_power_limit_mw <= 239*1000) {
830		value = slot_power_limit_mw / 1000;
831		scale = 0;
832		slot_power_limit_mw = slot_power_limit_mw / 1000 * 1000;
833	} else if (slot_power_limit_mw < 250*1000) {
834		value = 0xEF;
835		scale = 0;
836		slot_power_limit_mw = 239*1000;
837	} else if (slot_power_limit_mw <= 600*1000) {
838		value = 0xF0 + (slot_power_limit_mw / 1000 - 250) / 25;
839		scale = 0;
840		slot_power_limit_mw = slot_power_limit_mw / (1000*25) * (1000*25);
841	} else {
842		value = 0xFE;
843		scale = 0;
844		slot_power_limit_mw = 600*1000;
845	}
846
847	if (slot_power_limit_value)
848		*slot_power_limit_value = value;
849
850	if (slot_power_limit_scale)
851		*slot_power_limit_scale = scale;
852
853	return slot_power_limit_mw;
854}
855EXPORT_SYMBOL_GPL(of_pci_get_slot_power_limit);