1. 根目录:
2. arch
3. sparc
4. kernel
5. of_device_common.c

#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/export.h>
#include <linux/mod_devicetable.h>
#include <linux/errno.h>
#include <linux/irq.h>
#include <linux/of_platform.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>

#include "of_device_common.h"

unsigned int irq_of_parse_and_map(struct device_node *node, int index)
{
	struct platform_device *op = of_find_device_by_node(node);

	if (!op || index >= op->archdata.num_irqs)
		return 0;

	return op->archdata.irqs[index];
}
EXPORT_SYMBOL(irq_of_parse_and_map);

int of_address_to_resource(struct device_node *node, int index,
			   struct resource *r)
{
	struct platform_device *op = of_find_device_by_node(node);

	if (!op || index >= op->num_resources)
		return -EINVAL;

	memcpy(r, &op->archdata.resource[index], sizeof(*r));
	return 0;
}
EXPORT_SYMBOL_GPL(of_address_to_resource);

void __iomem *of_iomap(struct device_node *node, int index)
{
	struct platform_device *op = of_find_device_by_node(node);
	struct resource *r;

	if (!op || index >= op->num_resources)
		return NULL;

	r = &op->archdata.resource[index];

	return of_ioremap(r, 0, resource_size(r), (char *) r->name);
}
EXPORT_SYMBOL(of_iomap);

/* Take the archdata values for IOMMU, STC, and HOSTDATA found in
 * BUS and propagate to all child platform_device objects.
 */
void of_propagate_archdata(struct platform_device *bus)
{
	struct dev_archdata *bus_sd = &bus->dev.archdata;
	struct device_node *bus_dp = bus->dev.of_node;
	struct device_node *dp;

	for (dp = bus_dp->child; dp; dp = dp->sibling) {
		struct platform_device *op = of_find_device_by_node(dp);

		op->dev.archdata.iommu = bus_sd->iommu;
		op->dev.archdata.stc = bus_sd->stc;
		op->dev.archdata.host_controller = bus_sd->host_controller;
		op->dev.archdata.numa_node = bus_sd->numa_node;

		if (dp->child)
			of_propagate_archdata(op);
	}
}

static void get_cells(struct device_node *dp, int *addrc, int *sizec)
{
	if (addrc)
		*addrc = of_n_addr_cells(dp);
	if (sizec)
		*sizec = of_n_size_cells(dp);
}

/*
 * Default translator (generic bus)
 */

void of_bus_default_count_cells(struct device_node *dev, int *addrc, int *sizec)
{
	get_cells(dev, addrc, sizec);
}

/* Make sure the least significant 64-bits are in-range.  Even
 * for 3 or 4 cell values it is a good enough approximation.
 */
int of_out_of_range(const u32 *addr, const u32 *base,
		    const u32 *size, int na, int ns)
{
	u64 a = of_read_addr(addr, na);
	u64 b = of_read_addr(base, na);

	if (a < b)
		return 1;

	b += of_read_addr(size, ns);
	if (a >= b)
		return 1;

	return 0;
}

int of_bus_default_map(u32 *addr, const u32 *range, int na, int ns, int pna)
{
	u32 result[OF_MAX_ADDR_CELLS];
	int i;

	if (ns > 2) {
		printk("of_device: Cannot handle size cells (%d) > 2.", ns);
		return -EINVAL;
	}

	if (of_out_of_range(addr, range, range + na + pna, na, ns))
		return -EINVAL;

	/* Start with the parent range base.  */
	memcpy(result, range + na, pna * 4);

	/* Add in the child address offset.  */
	for (i = 0; i < na; i++)
		result[pna - 1 - i] +=
			(addr[na - 1 - i] -
			 range[na - 1 - i]);

	memcpy(addr, result, pna * 4);

	return 0;
}

unsigned long of_bus_default_get_flags(const u32 *addr, unsigned long flags)
{
	if (flags)
		return flags;
	return IORESOURCE_MEM;
}

/*
 * SBUS bus specific translator
 */

int of_bus_sbus_match(struct device_node *np)
{
	struct device_node *dp = np;

	while (dp) {
		if (!strcmp(dp->name, "sbus") ||
		    !strcmp(dp->name, "sbi"))
			return 1;

		/* Have a look at use_1to1_mapping().  We're trying
		 * to match SBUS if that's the top-level bus and we
		 * don't have some intervening real bus that provides
		 * ranges based translations.
		 */
		if (of_find_property(dp, "ranges", NULL) != NULL)
			break;

		dp = dp->parent;
	}

	return 0;
}

void of_bus_sbus_count_cells(struct device_node *child, int *addrc, int *sizec)
{
	if (addrc)
		*addrc = 2;
	if (sizec)
		*sizec = 1;
}