drivers/pci/of.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * PCI <-> OF mapping helpers
  *
  * Copyright 2011 IBM Corp.
  */
 #define pr_fmt(fmt)	"PCI: OF: " fmt

 #include <linux/irqdomain.h>
 #include <linux/kernel.h>
 #include <linux/pci.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
 #include <linux/of_address.h>
 #include <linux/of_pci.h>
 #include "pci.h"

 #ifdef CONFIG_PCI
 void pci_set_of_node(struct pci_dev *dev)
 {
 	if (!dev->bus->dev.of_node)
 		return;
 	dev->dev.of_node = of_pci_find_child_device(dev->bus->dev.of_node,
 						    dev->devfn);
 	if (dev->dev.of_node)
 		dev->dev.fwnode = &dev->dev.of_node->fwnode;
 }

 void pci_release_of_node(struct pci_dev *dev)
 {
 	of_node_put(dev->dev.of_node);
 	dev->dev.of_node = NULL;
 	dev->dev.fwnode = NULL;
 }

 void pci_set_bus_of_node(struct pci_bus *bus)
 {
 	struct device_node *node;

 	if (bus->self == NULL) {
 		node = pcibios_get_phb_of_node(bus);
 	} else {
 		node = of_node_get(bus->self->dev.of_node);
 		if (node && of_property_read_bool(node, "external-facing"))
 			bus->self->external_facing = true;
 	}

 	bus->dev.of_node = node;

 	if (bus->dev.of_node)
 		bus->dev.fwnode = &bus->dev.of_node->fwnode;
 }

 void pci_release_bus_of_node(struct pci_bus *bus)
 {
 	of_node_put(bus->dev.of_node);
 	bus->dev.of_node = NULL;
 	bus->dev.fwnode = NULL;
 }

 struct device_node * __weak pcibios_get_phb_of_node(struct pci_bus *bus)
 {
 	/* This should only be called for PHBs */
 	if (WARN_ON(bus->self || bus->parent))
 		return NULL;

 	/*
 	 * Look for a node pointer in either the intermediary device we
 	 * create above the root bus or its own parent. Normally only
 	 * the later is populated.
 	 */
 	if (bus->bridge->of_node)
 		return of_node_get(bus->bridge->of_node);
 	if (bus->bridge->parent && bus->bridge->parent->of_node)
 		return of_node_get(bus->bridge->parent->of_node);
 	return NULL;
 }

 struct irq_domain *pci_host_bridge_of_msi_domain(struct pci_bus *bus)
 {
 #ifdef CONFIG_IRQ_DOMAIN
 	struct irq_domain *d;

 	if (!bus->dev.of_node)
 		return NULL;

 	/* Start looking for a phandle to an MSI controller. */
 	d = of_msi_get_domain(&bus->dev, bus->dev.of_node, DOMAIN_BUS_PCI_MSI);
 	if (d)
 		return d;

 	/*
 	 * If we don't have an msi-parent property, look for a domain
 	 * directly attached to the host bridge.
 	 */
 	d = irq_find_matching_host(bus->dev.of_node, DOMAIN_BUS_PCI_MSI);
 	if (d)
 		return d;

 	return irq_find_host(bus->dev.of_node);
 #else
 	return NULL;
 #endif
 }

 bool pci_host_of_has_msi_map(struct device *dev)
 {
 	if (dev && dev->of_node)
 		return of_get_property(dev->of_node, "msi-map", NULL);
 	return false;
 }

 static inline int __of_pci_pci_compare(struct device_node *node,
 				       unsigned int data)
 {
 	int devfn;

 	devfn = of_pci_get_devfn(node);
 	if (devfn < 0)
 		return 0;

 	return devfn == data;
 }

 struct device_node *of_pci_find_child_device(struct device_node *parent,
 					     unsigned int devfn)
 {
 	struct device_node *node, *node2;

 	for_each_child_of_node(parent, node) {
 		if (__of_pci_pci_compare(node, devfn))
 			return node;
 		/*
 		 * Some OFs create a parent node "multifunc-device" as
 		 * a fake root for all functions of a multi-function
 		 * device we go down them as well.
 		 */
 		if (of_node_name_eq(node, "multifunc-device")) {
 			for_each_child_of_node(node, node2) {
 				if (__of_pci_pci_compare(node2, devfn)) {
 					of_node_put(node);
 					return node2;
 				}
 			}
 		}
 	}
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(of_pci_find_child_device);

 /**
  * of_pci_get_devfn() - Get device and function numbers for a device node
  * @np: device node
  *
  * Parses a standard 5-cell PCI resource and returns an 8-bit value that can
  * be passed to the PCI_SLOT() and PCI_FUNC() macros to extract the device
  * and function numbers respectively. On error a negative error code is
  * returned.
  */
 int of_pci_get_devfn(struct device_node *np)
 {
 	u32 reg[5];
 	int error;

 	error = of_property_read_u32_array(np, "reg", reg, ARRAY_SIZE(reg));
 	if (error)
 		return error;

 	return (reg[0] >> 8) & 0xff;
 }
 EXPORT_SYMBOL_GPL(of_pci_get_devfn);

 /**
  * of_pci_parse_bus_range() - parse the bus-range property of a PCI device
  * @node: device node
  * @res: address to a struct resource to return the bus-range
  *
  * Returns 0 on success or a negative error-code on failure.
  */
 int of_pci_parse_bus_range(struct device_node *node, struct resource *res)
 {
 	u32 bus_range[2];
 	int error;

 	error = of_property_read_u32_array(node, "bus-range", bus_range,
 					   ARRAY_SIZE(bus_range));
 	if (error)
 		return error;

 	res->name = node->name;
 	res->start = bus_range[0];
 	res->end = bus_range[1];
 	res->flags = IORESOURCE_BUS;

 	return 0;
 }
 EXPORT_SYMBOL_GPL(of_pci_parse_bus_range);

 /**
  * This function will try to obtain the host bridge domain number by
  * finding a property called "linux,pci-domain" of the given device node.
  *
  * @node: device tree node with the domain information
  *
  * Returns the associated domain number from DT in the range [0-0xffff], or
  * a negative value if the required property is not found.
  */
 int of_get_pci_domain_nr(struct device_node *node)
 {
 	u32 domain;
 	int error;

 	error = of_property_read_u32(node, "linux,pci-domain", &domain);
 	if (error)
 		return error;

 	return (u16)domain;
 }
 EXPORT_SYMBOL_GPL(of_get_pci_domain_nr);

 /**
  * of_pci_check_probe_only - Setup probe only mode if linux,pci-probe-only
  *                           is present and valid
  */
 void of_pci_check_probe_only(void)
 {
 	u32 val;
 	int ret;

 	ret = of_property_read_u32(of_chosen, "linux,pci-probe-only", &val);
 	if (ret) {
 		if (ret == -ENODATA || ret == -EOVERFLOW)
 			pr_warn("linux,pci-probe-only without valid value, ignoring\n");
 		return;
 	}

 	if (val)
 		pci_add_flags(PCI_PROBE_ONLY);
 	else
 		pci_clear_flags(PCI_PROBE_ONLY);

 	pr_info("PROBE_ONLY %sabled\n", val ? "en" : "dis");
 }
 EXPORT_SYMBOL_GPL(of_pci_check_probe_only);

 /**
  * devm_of_pci_get_host_bridge_resources() - Resource-managed parsing of PCI
  *                                           host bridge resources from DT
  * @dev: host bridge device
  * @busno: bus number associated with the bridge root bus
  * @bus_max: maximum number of buses for this bridge
  * @resources: list where the range of resources will be added after DT parsing
  * @ib_resources: list where the range of inbound resources (with addresses
  *                from 'dma-ranges') will be added after DT parsing
  * @io_base: pointer to a variable that will contain on return the physical
  * address for the start of the I/O range. Can be NULL if the caller doesn't
  * expect I/O ranges to be present in the device tree.
  *
  * This function will parse the "ranges" property of a PCI host bridge device
  * node and setup the resource mapping based on its content. It is expected
  * that the property conforms with the Power ePAPR document.
  *
  * It returns zero if the range parsing has been successful or a standard error
  * value if it failed.
  */
 static int devm_of_pci_get_host_bridge_resources(struct device *dev,
 			unsigned char busno, unsigned char bus_max,
 			struct list_head *resources,
 			struct list_head *ib_resources,
 			resource_size_t *io_base)
 {
 	struct device_node *dev_node = dev->of_node;
 	struct resource *res, tmp_res;
 	struct resource *bus_range;
 	struct of_pci_range range;
 	struct of_pci_range_parser parser;
 	const char *range_type;
 	int err;

 	if (io_base)
 		*io_base = (resource_size_t)OF_BAD_ADDR;

 	bus_range = devm_kzalloc(dev, sizeof(*bus_range), GFP_KERNEL);
 	if (!bus_range)
 		return -ENOMEM;

 	dev_info(dev, "host bridge %pOF ranges:\n", dev_node);

 	err = of_pci_parse_bus_range(dev_node, bus_range);
 	if (err) {
 		bus_range->start = busno;
 		bus_range->end = bus_max;
 		bus_range->flags = IORESOURCE_BUS;
 		dev_info(dev, "  No bus range found for %pOF, using %pR\n",
 			 dev_node, bus_range);
 	} else {
 		if (bus_range->end > bus_range->start + bus_max)
 			bus_range->end = bus_range->start + bus_max;
 	}
 	pci_add_resource(resources, bus_range);

 	/* Check for ranges property */
 	err = of_pci_range_parser_init(&parser, dev_node);
 	if (err)
 		return 0;

 	dev_dbg(dev, "Parsing ranges property...\n");
 	for_each_of_pci_range(&parser, &range) {
 		/* Read next ranges element */
 		if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_IO)
 			range_type = "IO";
 		else if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_MEM)
 			range_type = "MEM";
 		else
 			range_type = "err";
 		dev_info(dev, "  %6s %#012llx..%#012llx -> %#012llx\n",
 			 range_type, range.cpu_addr,
 			 range.cpu_addr + range.size - 1, range.pci_addr);

 		/*
 		 * If we failed translation or got a zero-sized region
 		 * then skip this range
 		 */
 		if (range.cpu_addr == OF_BAD_ADDR || range.size == 0)
 			continue;

 		err = of_pci_range_to_resource(&range, dev_node, &tmp_res);
 		if (err)
 			continue;

 		res = devm_kmemdup(dev, &tmp_res, sizeof(tmp_res), GFP_KERNEL);
 		if (!res) {
 			err = -ENOMEM;
 			goto failed;
 		}

 		if (resource_type(res) == IORESOURCE_IO) {
 			if (!io_base) {
 				dev_err(dev, "I/O range found for %pOF. Please provide an io_base pointer to save CPU base address\n",
 					dev_node);
 				err = -EINVAL;
 				goto failed;
 			}
 			if (*io_base != (resource_size_t)OF_BAD_ADDR)
 				dev_warn(dev, "More than one I/O resource converted for %pOF. CPU base address for old range lost!\n",
 					 dev_node);
 			*io_base = range.cpu_addr;
 		}

 		pci_add_resource_offset(resources, res,	res->start - range.pci_addr);
 	}

 	/* Check for dma-ranges property */
 	if (!ib_resources)
 		return 0;
 	err = of_pci_dma_range_parser_init(&parser, dev_node);
 	if (err)
 		return 0;

 	dev_dbg(dev, "Parsing dma-ranges property...\n");
 	for_each_of_pci_range(&parser, &range) {
 		struct resource_entry *entry;
 		/*
 		 * If we failed translation or got a zero-sized region
 		 * then skip this range
 		 */
 		if (((range.flags & IORESOURCE_TYPE_BITS) != IORESOURCE_MEM) ||
 		    range.cpu_addr == OF_BAD_ADDR || range.size == 0)
 			continue;

 		dev_info(dev, "  %6s %#012llx..%#012llx -> %#012llx\n",
 			 "IB MEM", range.cpu_addr,
 			 range.cpu_addr + range.size - 1, range.pci_addr);


 		err = of_pci_range_to_resource(&range, dev_node, &tmp_res);
 		if (err)
 			continue;

 		res = devm_kmemdup(dev, &tmp_res, sizeof(tmp_res), GFP_KERNEL);
 		if (!res) {
 			err = -ENOMEM;
 			goto failed;
 		}

 		/* Keep the resource list sorted */
 		resource_list_for_each_entry(entry, ib_resources)
 			if (entry->res->start > res->start)
 				break;

 		pci_add_resource_offset(&entry->node, res,
 					res->start - range.pci_addr);
 	}

 	return 0;

 failed:
 	pci_free_resource_list(resources);
 	return err;
 }

 #if IS_ENABLED(CONFIG_OF_IRQ)
 /**
  * of_irq_parse_pci - Resolve the interrupt for a PCI device
  * @pdev:       the device whose interrupt is to be resolved
  * @out_irq:    structure of_phandle_args filled by this function
  *
  * This function resolves the PCI interrupt for a given PCI device. If a
  * device-node exists for a given pci_dev, it will use normal OF tree
  * walking. If not, it will implement standard swizzling and walk up the
  * PCI tree until an device-node is found, at which point it will finish
  * resolving using the OF tree walking.
  */
 static int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
 {
 	struct device_node *dn, *ppnode;
 	struct pci_dev *ppdev;
 	__be32 laddr[3];
 	u8 pin;
 	int rc;

 	/*
 	 * Check if we have a device node, if yes, fallback to standard
 	 * device tree parsing
 	 */
 	dn = pci_device_to_OF_node(pdev);
 	if (dn) {
 		rc = of_irq_parse_one(dn, 0, out_irq);
 		if (!rc)
 			return rc;
 	}

 	/*
 	 * Ok, we don't, time to have fun. Let's start by building up an
 	 * interrupt spec.  we assume #interrupt-cells is 1, which is standard
 	 * for PCI. If you do different, then don't use that routine.
 	 */
 	rc = pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pin);
 	if (rc != 0)
 		goto err;
 	/* No pin, exit with no error message. */
 	if (pin == 0)
 		return -ENODEV;

 	/* Now we walk up the PCI tree */
 	for (;;) {
 		/* Get the pci_dev of our parent */
 		ppdev = pdev->bus->self;

 		/* Ouch, it's a host bridge... */
 		if (ppdev == NULL) {
 			ppnode = pci_bus_to_OF_node(pdev->bus);

 			/* No node for host bridge ? give up */
 			if (ppnode == NULL) {
 				rc = -EINVAL;
 				goto err;
 			}
 		} else {
 			/* We found a P2P bridge, check if it has a node */
 			ppnode = pci_device_to_OF_node(ppdev);
 		}

 		/*
 		 * Ok, we have found a parent with a device-node, hand over to
 		 * the OF parsing code.
 		 * We build a unit address from the linux device to be used for
 		 * resolution. Note that we use the linux bus number which may
 		 * not match your firmware bus numbering.
 		 * Fortunately, in most cases, interrupt-map-mask doesn't
 		 * include the bus number as part of the matching.
 		 * You should still be careful about that though if you intend
 		 * to rely on this function (you ship a firmware that doesn't
 		 * create device nodes for all PCI devices).
 		 */
 		if (ppnode)
 			break;

 		/*
 		 * We can only get here if we hit a P2P bridge with no node;
 		 * let's do standard swizzling and try again
 		 */
 		pin = pci_swizzle_interrupt_pin(pdev, pin);
 		pdev = ppdev;
 	}

 	out_irq->np = ppnode;
 	out_irq->args_count = 1;
 	out_irq->args[0] = pin;
 	laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8));
 	laddr[1] = laddr[2] = cpu_to_be32(0);
 	rc = of_irq_parse_raw(laddr, out_irq);
 	if (rc)
 		goto err;
 	return 0;
 err:
 	if (rc == -ENOENT) {
 		dev_warn(&pdev->dev,
 			"%s: no interrupt-map found, INTx interrupts not available\n",
 			__func__);
 		pr_warn_once("%s: possibly some PCI slots don't have level triggered interrupts capability\n",
 			__func__);
 	} else {
 		dev_err(&pdev->dev, "%s: failed with rc=%d\n", __func__, rc);
 	}
 	return rc;
 }

 /**
  * of_irq_parse_and_map_pci() - Decode a PCI IRQ from the device tree and map to a VIRQ
  * @dev: The PCI device needing an IRQ
  * @slot: PCI slot number; passed when used as map_irq callback. Unused
  * @pin: PCI IRQ pin number; passed when used as map_irq callback. Unused
  *
  * @slot and @pin are unused, but included in the function so that this
  * function can be used directly as the map_irq callback to
  * pci_assign_irq() and struct pci_host_bridge.map_irq pointer
  */
 int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin)
 {
 	struct of_phandle_args oirq;
 	int ret;

 	ret = of_irq_parse_pci(dev, &oirq);
 	if (ret)
 		return 0; /* Proper return code 0 == NO_IRQ */

 	return irq_create_of_mapping(&oirq);
 }
 EXPORT_SYMBOL_GPL(of_irq_parse_and_map_pci);
 #endif	/* CONFIG_OF_IRQ */

 static int pci_parse_request_of_pci_ranges(struct device *dev,
 					   struct pci_host_bridge *bridge)
 {
 	int err, res_valid = 0;
 	resource_size_t iobase;
 	struct resource_entry *win, *tmp;

 	INIT_LIST_HEAD(&bridge->windows);
 	INIT_LIST_HEAD(&bridge->dma_ranges);

 	err = devm_of_pci_get_host_bridge_resources(dev, 0, 0xff, &bridge->windows,
 						    &bridge->dma_ranges, &iobase);
 	if (err)
 		return err;

 	err = devm_request_pci_bus_resources(dev, &bridge->windows);
 	if (err)
 		return err;

 	resource_list_for_each_entry_safe(win, tmp, &bridge->windows) {
 		struct resource *res = win->res;

 		switch (resource_type(res)) {
 		case IORESOURCE_IO:
 			err = devm_pci_remap_iospace(dev, res, iobase);
 			if (err) {
 				dev_warn(dev, "error %d: failed to map resource %pR\n",
 					 err, res);
 				resource_list_destroy_entry(win);
 			}
 			break;
 		case IORESOURCE_MEM:
 			res_valid |= !(res->flags & IORESOURCE_PREFETCH);
 			break;
 		}
 	}

 	if (!res_valid)
 		dev_warn(dev, "non-prefetchable memory resource required\n");

 	return 0;
 }

 int devm_of_pci_bridge_init(struct device *dev, struct pci_host_bridge *bridge)
 {
 	if (!dev->of_node)
 		return 0;

 	bridge->swizzle_irq = pci_common_swizzle;
 	bridge->map_irq = of_irq_parse_and_map_pci;

 	return pci_parse_request_of_pci_ranges(dev, bridge);
 }

 #endif /* CONFIG_PCI */

 /**
  * This function will try to find the limitation of link speed by finding
  * a property called "max-link-speed" of the given device node.
  *
  * @node: device tree node with the max link speed information
  *
  * Returns the associated max link speed from DT, or a negative value if the
  * required property is not found or is invalid.
  */
 int of_pci_get_max_link_speed(struct device_node *node)
 {
 	u32 max_link_speed;

 	if (of_property_read_u32(node, "max-link-speed", &max_link_speed) ||
 	    max_link_speed == 0 || max_link_speed > 4)
 		return -EINVAL;

 	return max_link_speed;
 }
 EXPORT_SYMBOL_GPL(of_pci_get_max_link_speed);
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* PCI <-> OF mapping helpers
	*
	* Copyright 2011 IBM Corp.
	*/
	#define pr_fmt(fmt) "PCI: OF: " fmt

	#include <linux/irqdomain.h>
	#include <linux/kernel.h>
	#include <linux/pci.h>
	#include <linux/of.h>
	#include <linux/of_irq.h>
	#include <linux/of_address.h>
	#include <linux/of_pci.h>
	#include "pci.h"

	#ifdef CONFIG_PCI
	void pci_set_of_node(struct pci_dev *dev)
	{
	if (!dev->bus->dev.of_node)
	return;
	dev->dev.of_node = of_pci_find_child_device(dev->bus->dev.of_node,
	dev->devfn);
	if (dev->dev.of_node)
	dev->dev.fwnode = &dev->dev.of_node->fwnode;
	}

	void pci_release_of_node(struct pci_dev *dev)
	{
	of_node_put(dev->dev.of_node);
	dev->dev.of_node = NULL;
	dev->dev.fwnode = NULL;
	}

	void pci_set_bus_of_node(struct pci_bus *bus)
	{
	struct device_node *node;

	if (bus->self == NULL) {
	node = pcibios_get_phb_of_node(bus);
	} else {
	node = of_node_get(bus->self->dev.of_node);
	if (node && of_property_read_bool(node, "external-facing"))
	bus->self->external_facing = true;
	}

	bus->dev.of_node = node;

	if (bus->dev.of_node)
	bus->dev.fwnode = &bus->dev.of_node->fwnode;
	}

	void pci_release_bus_of_node(struct pci_bus *bus)
	{
	of_node_put(bus->dev.of_node);
	bus->dev.of_node = NULL;
	bus->dev.fwnode = NULL;
	}

	struct device_node * __weak pcibios_get_phb_of_node(struct pci_bus *bus)
	{
	/* This should only be called for PHBs */
	if (WARN_ON(bus->self \|\| bus->parent))
	return NULL;

	/*
	* Look for a node pointer in either the intermediary device we
	* create above the root bus or its own parent. Normally only
	* the later is populated.
	*/
	if (bus->bridge->of_node)
	return of_node_get(bus->bridge->of_node);
	if (bus->bridge->parent && bus->bridge->parent->of_node)
	return of_node_get(bus->bridge->parent->of_node);
	return NULL;
	}

	struct irq_domain pci_host_bridge_of_msi_domain(struct pci_bus bus)
	{
	#ifdef CONFIG_IRQ_DOMAIN
	struct irq_domain *d;

	if (!bus->dev.of_node)
	return NULL;

	/* Start looking for a phandle to an MSI controller. */
	d = of_msi_get_domain(&bus->dev, bus->dev.of_node, DOMAIN_BUS_PCI_MSI);
	if (d)
	return d;

	/*
	* If we don't have an msi-parent property, look for a domain
	* directly attached to the host bridge.
	*/
	d = irq_find_matching_host(bus->dev.of_node, DOMAIN_BUS_PCI_MSI);
	if (d)
	return d;

	return irq_find_host(bus->dev.of_node);
	#else
	return NULL;
	#endif
	}

	bool pci_host_of_has_msi_map(struct device *dev)
	{
	if (dev && dev->of_node)
	return of_get_property(dev->of_node, "msi-map", NULL);
	return false;
	}

	static inline int __of_pci_pci_compare(struct device_node *node,
	unsigned int data)
	{
	int devfn;

	devfn = of_pci_get_devfn(node);
	if (devfn < 0)
	return 0;

	return devfn == data;
	}

	struct device_node of_pci_find_child_device(struct device_node parent,
	unsigned int devfn)
	{
	struct device_node node, node2;

	for_each_child_of_node(parent, node) {
	if (__of_pci_pci_compare(node, devfn))
	return node;
	/*
	* Some OFs create a parent node "multifunc-device" as
	* a fake root for all functions of a multi-function
	* device we go down them as well.
	*/
	if (of_node_name_eq(node, "multifunc-device")) {
	for_each_child_of_node(node, node2) {
	if (__of_pci_pci_compare(node2, devfn)) {
	of_node_put(node);
	return node2;
	}
	}
	}
	}
	return NULL;
	}
	EXPORT_SYMBOL_GPL(of_pci_find_child_device);

	/**
	* of_pci_get_devfn() - Get device and function numbers for a device node
	* @np: device node
	*
	* Parses a standard 5-cell PCI resource and returns an 8-bit value that can
	* be passed to the PCI_SLOT() and PCI_FUNC() macros to extract the device
	* and function numbers respectively. On error a negative error code is
	* returned.
	*/
	int of_pci_get_devfn(struct device_node *np)
	{
	u32 reg[5];
	int error;

	error = of_property_read_u32_array(np, "reg", reg, ARRAY_SIZE(reg));
	if (error)
	return error;

	return (reg[0] >> 8) & 0xff;
	}
	EXPORT_SYMBOL_GPL(of_pci_get_devfn);

	/**
	* of_pci_parse_bus_range() - parse the bus-range property of a PCI device
	* @node: device node
	* @res: address to a struct resource to return the bus-range
	*
	* Returns 0 on success or a negative error-code on failure.
	*/
	int of_pci_parse_bus_range(struct device_node node, struct resource res)
	{
	u32 bus_range[2];
	int error;

	error = of_property_read_u32_array(node, "bus-range", bus_range,
	ARRAY_SIZE(bus_range));
	if (error)
	return error;

	res->name = node->name;
	res->start = bus_range[0];
	res->end = bus_range[1];
	res->flags = IORESOURCE_BUS;

	return 0;
	}
	EXPORT_SYMBOL_GPL(of_pci_parse_bus_range);

	/**
	* This function will try to obtain the host bridge domain number by
	* finding a property called "linux,pci-domain" of the given device node.
	*
	* @node: device tree node with the domain information
	*
	* Returns the associated domain number from DT in the range [0-0xffff], or
	* a negative value if the required property is not found.
	*/
	int of_get_pci_domain_nr(struct device_node *node)
	{
	u32 domain;
	int error;

	error = of_property_read_u32(node, "linux,pci-domain", &domain);
	if (error)
	return error;

	return (u16)domain;
	}
	EXPORT_SYMBOL_GPL(of_get_pci_domain_nr);

	/**
	* of_pci_check_probe_only - Setup probe only mode if linux,pci-probe-only
	* is present and valid
	*/
	void of_pci_check_probe_only(void)
	{
	u32 val;
	int ret;

	ret = of_property_read_u32(of_chosen, "linux,pci-probe-only", &val);
	if (ret) {
	if (ret == -ENODATA \|\| ret == -EOVERFLOW)
	pr_warn("linux,pci-probe-only without valid value, ignoring\n");
	return;
	}

	if (val)
	pci_add_flags(PCI_PROBE_ONLY);
	else
	pci_clear_flags(PCI_PROBE_ONLY);

	pr_info("PROBE_ONLY %sabled\n", val ? "en" : "dis");
	}
	EXPORT_SYMBOL_GPL(of_pci_check_probe_only);

	/**
	* devm_of_pci_get_host_bridge_resources() - Resource-managed parsing of PCI
	* host bridge resources from DT
	* @dev: host bridge device
	* @busno: bus number associated with the bridge root bus
	* @bus_max: maximum number of buses for this bridge
	* @resources: list where the range of resources will be added after DT parsing
	* @ib_resources: list where the range of inbound resources (with addresses
	* from 'dma-ranges') will be added after DT parsing
	* @io_base: pointer to a variable that will contain on return the physical
	* address for the start of the I/O range. Can be NULL if the caller doesn't
	* expect I/O ranges to be present in the device tree.
	*
	* This function will parse the "ranges" property of a PCI host bridge device
	* node and setup the resource mapping based on its content. It is expected
	* that the property conforms with the Power ePAPR document.
	*
	* It returns zero if the range parsing has been successful or a standard error
	* value if it failed.
	*/
	static int devm_of_pci_get_host_bridge_resources(struct device *dev,
	unsigned char busno, unsigned char bus_max,
	struct list_head *resources,
	struct list_head *ib_resources,
	resource_size_t *io_base)
	{
	struct device_node *dev_node = dev->of_node;
	struct resource *res, tmp_res;
	struct resource *bus_range;
	struct of_pci_range range;
	struct of_pci_range_parser parser;
	const char *range_type;
	int err;

	if (io_base)
	*io_base = (resource_size_t)OF_BAD_ADDR;

	bus_range = devm_kzalloc(dev, sizeof(*bus_range), GFP_KERNEL);
	if (!bus_range)
	return -ENOMEM;

	dev_info(dev, "host bridge %pOF ranges:\n", dev_node);

	err = of_pci_parse_bus_range(dev_node, bus_range);
	if (err) {
	bus_range->start = busno;
	bus_range->end = bus_max;
	bus_range->flags = IORESOURCE_BUS;
	dev_info(dev, " No bus range found for %pOF, using %pR\n",
	dev_node, bus_range);
	} else {
	if (bus_range->end > bus_range->start + bus_max)
	bus_range->end = bus_range->start + bus_max;
	}
	pci_add_resource(resources, bus_range);

	/* Check for ranges property */
	err = of_pci_range_parser_init(&parser, dev_node);
	if (err)
	return 0;

	dev_dbg(dev, "Parsing ranges property...\n");
	for_each_of_pci_range(&parser, &range) {
	/* Read next ranges element */
	if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_IO)
	range_type = "IO";
	else if ((range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_MEM)
	range_type = "MEM";
	else
	range_type = "err";
	dev_info(dev, " %6s %#012llx..%#012llx -> %#012llx\n",
	range_type, range.cpu_addr,
	range.cpu_addr + range.size - 1, range.pci_addr);

	/*
	* If we failed translation or got a zero-sized region
	* then skip this range
	*/
	if (range.cpu_addr == OF_BAD_ADDR \|\| range.size == 0)
	continue;

	err = of_pci_range_to_resource(&range, dev_node, &tmp_res);
	if (err)
	continue;

	res = devm_kmemdup(dev, &tmp_res, sizeof(tmp_res), GFP_KERNEL);
	if (!res) {
	err = -ENOMEM;
	goto failed;
	}

	if (resource_type(res) == IORESOURCE_IO) {
	if (!io_base) {
	dev_err(dev, "I/O range found for %pOF. Please provide an io_base pointer to save CPU base address\n",
	dev_node);
	err = -EINVAL;
	goto failed;
	}
	if (*io_base != (resource_size_t)OF_BAD_ADDR)
	dev_warn(dev, "More than one I/O resource converted for %pOF. CPU base address for old range lost!\n",
	dev_node);
	*io_base = range.cpu_addr;
	}

	pci_add_resource_offset(resources, res, res->start - range.pci_addr);
	}

	/* Check for dma-ranges property */
	if (!ib_resources)
	return 0;
	err = of_pci_dma_range_parser_init(&parser, dev_node);
	if (err)
	return 0;

	dev_dbg(dev, "Parsing dma-ranges property...\n");
	for_each_of_pci_range(&parser, &range) {
	struct resource_entry *entry;
	/*
	* If we failed translation or got a zero-sized region
	* then skip this range
	*/
	if (((range.flags & IORESOURCE_TYPE_BITS) != IORESOURCE_MEM) \|\|
	range.cpu_addr == OF_BAD_ADDR \|\| range.size == 0)
	continue;

	dev_info(dev, " %6s %#012llx..%#012llx -> %#012llx\n",
	"IB MEM", range.cpu_addr,
	range.cpu_addr + range.size - 1, range.pci_addr);


	err = of_pci_range_to_resource(&range, dev_node, &tmp_res);
	if (err)
	continue;

	res = devm_kmemdup(dev, &tmp_res, sizeof(tmp_res), GFP_KERNEL);
	if (!res) {
	err = -ENOMEM;
	goto failed;
	}

	/* Keep the resource list sorted */
	resource_list_for_each_entry(entry, ib_resources)
	if (entry->res->start > res->start)
	break;

	pci_add_resource_offset(&entry->node, res,
	res->start - range.pci_addr);
	}

	return 0;

	failed:
	pci_free_resource_list(resources);
	return err;
	}

	#if IS_ENABLED(CONFIG_OF_IRQ)
	/**
	* of_irq_parse_pci - Resolve the interrupt for a PCI device
	* @pdev: the device whose interrupt is to be resolved
	* @out_irq: structure of_phandle_args filled by this function
	*
	* This function resolves the PCI interrupt for a given PCI device. If a
	* device-node exists for a given pci_dev, it will use normal OF tree
	* walking. If not, it will implement standard swizzling and walk up the
	* PCI tree until an device-node is found, at which point it will finish
	* resolving using the OF tree walking.
	*/
	static int of_irq_parse_pci(const struct pci_dev pdev, struct of_phandle_args out_irq)
	{
	struct device_node dn, ppnode;
	struct pci_dev *ppdev;
	__be32 laddr[3];
	u8 pin;
	int rc;

	/*
	* Check if we have a device node, if yes, fallback to standard
	* device tree parsing
	*/
	dn = pci_device_to_OF_node(pdev);
	if (dn) {
	rc = of_irq_parse_one(dn, 0, out_irq);
	if (!rc)
	return rc;
	}

	/*
	* Ok, we don't, time to have fun. Let's start by building up an
	* interrupt spec. we assume #interrupt-cells is 1, which is standard
	* for PCI. If you do different, then don't use that routine.
	*/
	rc = pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pin);
	if (rc != 0)
	goto err;
	/* No pin, exit with no error message. */
	if (pin == 0)
	return -ENODEV;

	/* Now we walk up the PCI tree */
	for (;;) {
	/* Get the pci_dev of our parent */
	ppdev = pdev->bus->self;

	/* Ouch, it's a host bridge... */
	if (ppdev == NULL) {
	ppnode = pci_bus_to_OF_node(pdev->bus);

	/* No node for host bridge ? give up */
	if (ppnode == NULL) {
	rc = -EINVAL;
	goto err;
	}
	} else {
	/* We found a P2P bridge, check if it has a node */
	ppnode = pci_device_to_OF_node(ppdev);
	}

	/*
	* Ok, we have found a parent with a device-node, hand over to
	* the OF parsing code.
	* We build a unit address from the linux device to be used for
	* resolution. Note that we use the linux bus number which may
	* not match your firmware bus numbering.
	* Fortunately, in most cases, interrupt-map-mask doesn't
	* include the bus number as part of the matching.
	* You should still be careful about that though if you intend
	* to rely on this function (you ship a firmware that doesn't
	* create device nodes for all PCI devices).
	*/
	if (ppnode)
	break;

	/*
	* We can only get here if we hit a P2P bridge with no node;
	* let's do standard swizzling and try again
	*/
	pin = pci_swizzle_interrupt_pin(pdev, pin);
	pdev = ppdev;
	}

	out_irq->np = ppnode;
	out_irq->args_count = 1;
	out_irq->args[0] = pin;
	laddr[0] = cpu_to_be32((pdev->bus->number << 16) \| (pdev->devfn << 8));
	laddr[1] = laddr[2] = cpu_to_be32(0);
	rc = of_irq_parse_raw(laddr, out_irq);
	if (rc)
	goto err;
	return 0;
	err:
	if (rc == -ENOENT) {
	dev_warn(&pdev->dev,
	"%s: no interrupt-map found, INTx interrupts not available\n",
	__func__);
	pr_warn_once("%s: possibly some PCI slots don't have level triggered interrupts capability\n",
	__func__);
	} else {
	dev_err(&pdev->dev, "%s: failed with rc=%d\n", __func__, rc);
	}
	return rc;
	}

	/**
	* of_irq_parse_and_map_pci() - Decode a PCI IRQ from the device tree and map to a VIRQ
	* @dev: The PCI device needing an IRQ
	* @slot: PCI slot number; passed when used as map_irq callback. Unused
	* @pin: PCI IRQ pin number; passed when used as map_irq callback. Unused
	*
	* @slot and @pin are unused, but included in the function so that this
	* function can be used directly as the map_irq callback to
	* pci_assign_irq() and struct pci_host_bridge.map_irq pointer
	*/
	int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin)
	{
	struct of_phandle_args oirq;
	int ret;

	ret = of_irq_parse_pci(dev, &oirq);
	if (ret)
	return 0; /* Proper return code 0 == NO_IRQ */

	return irq_create_of_mapping(&oirq);
	}
	EXPORT_SYMBOL_GPL(of_irq_parse_and_map_pci);
	#endif /* CONFIG_OF_IRQ */

	static int pci_parse_request_of_pci_ranges(struct device *dev,
	struct pci_host_bridge *bridge)
	{
	int err, res_valid = 0;
	resource_size_t iobase;
	struct resource_entry win, tmp;

	INIT_LIST_HEAD(&bridge->windows);
	INIT_LIST_HEAD(&bridge->dma_ranges);

	err = devm_of_pci_get_host_bridge_resources(dev, 0, 0xff, &bridge->windows,
	&bridge->dma_ranges, &iobase);
	if (err)
	return err;

	err = devm_request_pci_bus_resources(dev, &bridge->windows);
	if (err)
	return err;

	resource_list_for_each_entry_safe(win, tmp, &bridge->windows) {
	struct resource *res = win->res;

	switch (resource_type(res)) {
	case IORESOURCE_IO:
	err = devm_pci_remap_iospace(dev, res, iobase);
	if (err) {
	dev_warn(dev, "error %d: failed to map resource %pR\n",
	err, res);
	resource_list_destroy_entry(win);
	}
	break;
	case IORESOURCE_MEM:
	res_valid \|= !(res->flags & IORESOURCE_PREFETCH);
	break;
	}
	}

	if (!res_valid)
	dev_warn(dev, "non-prefetchable memory resource required\n");

	return 0;
	}

	int devm_of_pci_bridge_init(struct device dev, struct pci_host_bridge bridge)
	{
	if (!dev->of_node)
	return 0;

	bridge->swizzle_irq = pci_common_swizzle;
	bridge->map_irq = of_irq_parse_and_map_pci;

	return pci_parse_request_of_pci_ranges(dev, bridge);
	}

	#endif /* CONFIG_PCI */

	/**
	* This function will try to find the limitation of link speed by finding
	* a property called "max-link-speed" of the given device node.
	*
	* @node: device tree node with the max link speed information
	*
	* Returns the associated max link speed from DT, or a negative value if the
	* required property is not found or is invalid.
	*/
	int of_pci_get_max_link_speed(struct device_node *node)
	{
	u32 max_link_speed;

	if (of_property_read_u32(node, "max-link-speed", &max_link_speed) \|\|
	max_link_speed == 0 \|\| max_link_speed > 4)
	return -EINVAL;

	return max_link_speed;
	}
	EXPORT_SYMBOL_GPL(of_pci_get_max_link_speed);