of_device.c

linux 内核源代码

#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/slab.h>

#include <asm/errno.h>
#include <asm/dcr.h>
#include <asm/of_device.h>

static void of_device_make_bus_id(struct of_device *dev)
{
	static atomic_t bus_no_reg_magic;
	struct device_node *node = dev->node;
	char *name = dev->dev.bus_id;
	const u32 *reg;
	u64 addr;
	int magic;

	/*
	 * If it's a DCR based device, use 'd' for native DCRs
	 * and 'D' for MMIO DCRs.
	 */
#ifdef CONFIG_PPC_DCR
	reg = of_get_property(node, "dcr-reg", NULL);
	if (reg) {
#ifdef CONFIG_PPC_DCR_NATIVE
		snprintf(name, BUS_ID_SIZE, "d%x.%s",
			 *reg, node->name);
#else /* CONFIG_PPC_DCR_NATIVE */
		addr = of_translate_dcr_address(node, *reg, NULL);
		if (addr != OF_BAD_ADDR) {
			snprintf(name, BUS_ID_SIZE,
				 "D%llx.%s", (unsigned long long)addr,
				 node->name);
			return;
		}
#endif /* !CONFIG_PPC_DCR_NATIVE */
	}
#endif /* CONFIG_PPC_DCR */

	/*
	 * For MMIO, get the physical address
	 */
	reg = of_get_property(node, "reg", NULL);
	if (reg) {
		addr = of_translate_address(node, reg);
		if (addr != OF_BAD_ADDR) {
			snprintf(name, BUS_ID_SIZE,
				 "%llx.%s", (unsigned long long)addr,
				 node->name);
			return;
		}
	}

	/*
	 * No BusID, use the node name and add a globally incremented
	 * counter (and pray...)
	 */
	magic = atomic_add_return(1, &bus_no_reg_magic);
	snprintf(name, BUS_ID_SIZE, "%s.%d", node->name, magic - 1);
}

struct of_device *of_device_alloc(struct device_node *np,
				  const char *bus_id,
				  struct device *parent)
{
	struct of_device *dev;

	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (!dev)
		return NULL;

	dev->node = of_node_get(np);
	dev->dev.dma_mask = &dev->dma_mask;
	dev->dev.parent = parent;
	dev->dev.release = of_release_dev;
	dev->dev.archdata.of_node = np;
	dev->dev.archdata.numa_node = of_node_to_nid(np);

	if (bus_id)
		strlcpy(dev->dev.bus_id, bus_id, BUS_ID_SIZE);
	else
		of_device_make_bus_id(dev);

	return dev;
}
EXPORT_SYMBOL(of_device_alloc);

ssize_t of_device_get_modalias(struct of_device *ofdev,
				char *str, ssize_t len)
{
	const char *compat;
	int cplen, i;
	ssize_t tsize, csize, repend;

	/* Name & Type */
	csize = snprintf(str, len, "of:N%sT%s",
				ofdev->node->name, ofdev->node->type);

	/* Get compatible property if any */
	compat = of_get_property(ofdev->node, "compatible", &cplen);
	if (!compat)
		return csize;

	/* Find true end (we tolerate multiple \0 at the end */
	for (i=(cplen-1); i>=0 && !compat[i]; i--)
		cplen--;
	if (!cplen)
		return csize;
	cplen++;

	/* Check space (need cplen+1 chars including final \0) */
	tsize = csize + cplen;
	repend = tsize;

	if (csize>=len)		/* @ the limit, all is already filled */
		return tsize;

	if (tsize>=len) {		/* limit compat list */
		cplen = len-csize-1;
		repend = len;
	}

	/* Copy and do char replacement */
	memcpy(&str[csize+1], compat, cplen);
	for (i=csize; i<repend; i++) {
		char c = str[i];
		if (c=='\0')
			str[i] = 'C';
		else if (c==' ')
			str[i] = '_';
	}

	return tsize;
}

int of_device_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	struct of_device *ofdev;
	const char *compat;
	int seen = 0, cplen, sl;

	if (!dev)
		return -ENODEV;

	ofdev = to_of_device(dev);

	if (add_uevent_var(env, "OF_NAME=%s", ofdev->node->name))
		return -ENOMEM;

	if (add_uevent_var(env, "OF_TYPE=%s", ofdev->node->type))
		return -ENOMEM;

        /* Since the compatible field can contain pretty much anything
         * it's not really legal to split it out with commas. We split it
         * up using a number of environment variables instead. */

	compat = of_get_property(ofdev->node, "compatible", &cplen);
	while (compat && *compat && cplen > 0) {
		if (add_uevent_var(env, "OF_COMPATIBLE_%d=%s", seen, compat))
			return -ENOMEM;

		sl = strlen (compat) + 1;
		compat += sl;
		cplen -= sl;
		seen++;
	}

	if (add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen))
		return -ENOMEM;

	/* modalias is trickier, we add it in 2 steps */
	if (add_uevent_var(env, "MODALIAS="))
		return -ENOMEM;
	sl = of_device_get_modalias(ofdev, &env->buf[env->buflen-1],
				    sizeof(env->buf) - env->buflen);
	if (sl >= (sizeof(env->buf) - env->buflen))
		return -ENOMEM;
	env->buflen += sl;

	return 0;
}
EXPORT_SYMBOL(of_device_uevent);
EXPORT_SYMBOL(of_device_get_modalias);