1. 根目录:
2. drivers
3. of
4. of_pci.c

#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/of.h>
#include <linux/of_pci.h>

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 (!strcmp(node->name, "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)
{
	unsigned int size;
	const __be32 *reg;

	reg = of_get_property(np, "reg", &size);

	if (!reg || size < 5 * sizeof(__be32))
		return -EINVAL;

	return (be32_to_cpup(reg) >> 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)
{
	const __be32 *values;
	int len;

	values = of_get_property(node, "bus-range", &len);
	if (!values || len < sizeof(*values) * 2)
		return -EINVAL;

	res->name = node->name;
	res->start = be32_to_cpup(values++);
	res->end = be32_to_cpup(values);
	res->flags = IORESOURCE_BUS;

	return 0;
}
EXPORT_SYMBOL_GPL(of_pci_parse_bus_range);

#ifdef CONFIG_PCI_MSI

static LIST_HEAD(of_pci_msi_chip_list);
static DEFINE_MUTEX(of_pci_msi_chip_mutex);

int of_pci_msi_chip_add(struct msi_chip *chip)
{
	if (!of_property_read_bool(chip->of_node, "msi-controller"))
		return -EINVAL;

	mutex_lock(&of_pci_msi_chip_mutex);
	list_add(&chip->list, &of_pci_msi_chip_list);
	mutex_unlock(&of_pci_msi_chip_mutex);

	return 0;
}
EXPORT_SYMBOL_GPL(of_pci_msi_chip_add);

void of_pci_msi_chip_remove(struct msi_chip *chip)
{
	mutex_lock(&of_pci_msi_chip_mutex);
	list_del(&chip->list);
	mutex_unlock(&of_pci_msi_chip_mutex);
}
EXPORT_SYMBOL_GPL(of_pci_msi_chip_remove);

struct msi_chip *of_pci_find_msi_chip_by_node(struct device_node *of_node)
{
	struct msi_chip *c;

	mutex_lock(&of_pci_msi_chip_mutex);
	list_for_each_entry(c, &of_pci_msi_chip_list, list) {
		if (c->of_node == of_node) {
			mutex_unlock(&of_pci_msi_chip_mutex);
			return c;
		}
	}
	mutex_unlock(&of_pci_msi_chip_mutex);

	return NULL;
}
EXPORT_SYMBOL_GPL(of_pci_find_msi_chip_by_node);

#endif /* CONFIG_PCI_MSI */