prom.c

底层驱动开发

 * Note that property management will need some locking as well,
 * this isn't dealt with yet.
 *
 *******/

/**
 *	of_find_node_by_name - Find a node by its "name" property
 *	@from:	The node to start searching from or NULL, the node
 *		you pass will not be searched, only the next one
 *		will; typically, you pass what the previous call
 *		returned. of_node_put() will be called on it
 *	@name:	The name string to match against
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_by_name(struct device_node *from,
	const char *name)
{
	struct device_node *np;

	read_lock(&devtree_lock);
	np = from ? from->allnext : allnodes;
	for (; np != 0; np = np->allnext)
		if (np->name != 0 && strcasecmp(np->name, name) == 0
		    && of_node_get(np))
			break;
	if (from)
		of_node_put(from);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_node_by_name);

/**
 *	of_find_node_by_type - Find a node by its "device_type" property
 *	@from:	The node to start searching from or NULL, the node
 *		you pass will not be searched, only the next one
 *		will; typically, you pass what the previous call
 *		returned. of_node_put() will be called on it
 *	@name:	The type string to match against
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_by_type(struct device_node *from,
	const char *type)
{
	struct device_node *np;

	read_lock(&devtree_lock);
	np = from ? from->allnext : allnodes;
	for (; np != 0; np = np->allnext)
		if (np->type != 0 && strcasecmp(np->type, type) == 0
		    && of_node_get(np))
			break;
	if (from)
		of_node_put(from);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_node_by_type);

/**
 *	of_find_compatible_node - Find a node based on type and one of the
 *                                tokens in its "compatible" property
 *	@from:		The node to start searching from or NULL, the node
 *			you pass will not be searched, only the next one
 *			will; typically, you pass what the previous call
 *			returned. of_node_put() will be called on it
 *	@type:		The type string to match "device_type" or NULL to ignore
 *	@compatible:	The string to match to one of the tokens in the device
 *			"compatible" list.
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_compatible_node(struct device_node *from,
	const char *type, const char *compatible)
{
	struct device_node *np;

	read_lock(&devtree_lock);
	np = from ? from->allnext : allnodes;
	for (; np != 0; np = np->allnext) {
		if (type != NULL
		    && !(np->type != 0 && strcasecmp(np->type, type) == 0))
			continue;
		if (device_is_compatible(np, compatible) && of_node_get(np))
			break;
	}
	if (from)
		of_node_put(from);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_compatible_node);

/**
 *	of_find_node_by_path - Find a node matching a full OF path
 *	@path:	The full path to match
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_by_path(const char *path)
{
	struct device_node *np = allnodes;

	read_lock(&devtree_lock);
	for (; np != 0; np = np->allnext) {
		if (np->full_name != 0 && strcasecmp(np->full_name, path) == 0
		    && of_node_get(np))
			break;
	}
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_node_by_path);

/**
 *	of_find_node_by_phandle - Find a node given a phandle
 *	@handle:	phandle of the node to find
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_by_phandle(phandle handle)
{
	struct device_node *np;

	read_lock(&devtree_lock);
	for (np = allnodes; np != 0; np = np->allnext)
		if (np->linux_phandle == handle)
			break;
	if (np)
		of_node_get(np);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_node_by_phandle);

/**
 *	of_find_all_nodes - Get next node in global list
 *	@prev:	Previous node or NULL to start iteration
 *		of_node_put() will be called on it
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_all_nodes(struct device_node *prev)
{
	struct device_node *np;

	read_lock(&devtree_lock);
	np = prev ? prev->allnext : allnodes;
	for (; np != 0; np = np->allnext)
		if (of_node_get(np))
			break;
	if (prev)
		of_node_put(prev);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_find_all_nodes);

/**
 *	of_get_parent - Get a node's parent if any
 *	@node:	Node to get parent
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_get_parent(const struct device_node *node)
{
	struct device_node *np;

	if (!node)
		return NULL;

	read_lock(&devtree_lock);
	np = of_node_get(node->parent);
	read_unlock(&devtree_lock);
	return np;
}
EXPORT_SYMBOL(of_get_parent);

/**
 *	of_get_next_child - Iterate a node childs
 *	@node:	parent node
 *	@prev:	previous child of the parent node, or NULL to get first
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_get_next_child(const struct device_node *node,
	struct device_node *prev)
{
	struct device_node *next;

	read_lock(&devtree_lock);
	next = prev ? prev->sibling : node->child;
	for (; next != 0; next = next->sibling)
		if (of_node_get(next))
			break;
	if (prev)
		of_node_put(prev);
	read_unlock(&devtree_lock);
	return next;
}
EXPORT_SYMBOL(of_get_next_child);

/**
 *	of_node_get - Increment refcount of a node
 *	@node:	Node to inc refcount, NULL is supported to
 *		simplify writing of callers
 *
 *	Returns node.
 */
struct device_node *of_node_get(struct device_node *node)
{
	if (node)
		kref_get(&node->kref);
	return node;
}
EXPORT_SYMBOL(of_node_get);

static inline struct device_node * kref_to_device_node(struct kref *kref)
{
	return container_of(kref, struct device_node, kref);
}

/**
 *	of_node_release - release a dynamically allocated node
 *	@kref:  kref element of the node to be released
 *
 *	In of_node_put() this function is passed to kref_put()
 *	as the destructor.
 */
static void of_node_release(struct kref *kref)
{
	struct device_node *node = kref_to_device_node(kref);
	struct property *prop = node->properties;

	if (!OF_IS_DYNAMIC(node))
		return;
	while (prop) {
		struct property *next = prop->next;
		kfree(prop->name);
		kfree(prop->value);
		kfree(prop);
		prop = next;
	}
	kfree(node->intrs);
	kfree(node->addrs);
	kfree(node->full_name);
	kfree(node->data);
	kfree(node);
}

/**
 *	of_node_put - Decrement refcount of a node
 *	@node:	Node to dec refcount, NULL is supported to
 *		simplify writing of callers
 *
 */
void of_node_put(struct device_node *node)
{
	if (node)
		kref_put(&node->kref, of_node_release);
}
EXPORT_SYMBOL(of_node_put);

/*
 * Fix up the uninitialized fields in a new device node:
 * name, type, n_addrs, addrs, n_intrs, intrs, and pci-specific fields
 *
 * A lot of boot-time code is duplicated here, because functions such
 * as finish_node_interrupts, interpret_pci_props, etc. cannot use the
 * slab allocator.
 *
 * This should probably be split up into smaller chunks.
 */

static int of_finish_dynamic_node(struct device_node *node,
				  unsigned long *unused1, int unused2,
				  int unused3, int unused4)
{
	struct device_node *parent = of_get_parent(node);
	int err = 0;
	phandle *ibm_phandle;

	node->name = get_property(node, "name", NULL);
	node->type = get_property(node, "device_type", NULL);

	if (!parent) {
		err = -ENODEV;
		goto out;
	}

	/* We don't support that function on PowerMac, at least
	 * not yet
	 */
	if (systemcfg->platform == PLATFORM_POWERMAC)
		return -ENODEV;

	/* fix up new node's linux_phandle field */
	if ((ibm_phandle = (unsigned int *)get_property(node, "ibm,phandle", NULL)))
		node->linux_phandle = *ibm_phandle;

out:
	of_node_put(parent);
	return err;
}

/*
 * Plug a device node into the tree and global list.
 */
void of_attach_node(struct device_node *np)
{
	write_lock(&devtree_lock);
	np->sibling = np->parent->child;
	np->allnext = allnodes;
	np->parent->child = np;
	allnodes = np;
	write_unlock(&devtree_lock);
}

/*
 * "Unplug" a node from the device tree.  The caller must hold
 * a reference to the node.  The memory associated with the node
 * is not freed until its refcount goes to zero.
 */
void of_detach_node(const struct device_node *np)
{
	struct device_node *parent;

	write_lock(&devtree_lock);

	parent = np->parent;

	if (allnodes == np)
		allnodes = np->allnext;
	else {
		struct device_node *prev;
		for (prev = allnodes;
		     prev->allnext != np;
		     prev = prev->allnext)
			;
		prev->allnext = np->allnext;
	}

	if (parent->child == np)
		parent->child = np->sibling;
	else {
		struct device_node *prevsib;
		for (prevsib = np->parent->child;
		     prevsib->sibling != np;
		     prevsib = prevsib->sibling)
			;
		prevsib->sibling = np->sibling;
	}

	write_unlock(&devtree_lock);
}

static int prom_reconfig_notifier(struct notifier_block *nb, unsigned long action, void *node)
{
	int err;

	switch (action) {
	case PSERIES_RECONFIG_ADD:
		err = finish_node(node, NULL, of_finish_dynamic_node, 0, 0, 0);
		if (err < 0) {
			printk(KERN_ERR "finish_node returned %d\n", err);
			err = NOTIFY_BAD;
		}
		break;
	default:
		err = NOTIFY_DONE;
		break;
	}
	return err;
}

static struct notifier_block prom_reconfig_nb = {
	.notifier_call = prom_reconfig_notifier,
	.priority = 10, /* This one needs to run first */
};

static int __init prom_reconfig_setup(void)
{
	return pSeries_reconfig_notifier_register(&prom_reconfig_nb);
}
__initcall(prom_reconfig_setup);

/*
 * Find a property with a given name for a given node
 * and return the value.
 */
unsigned char *
get_property(struct device_node *np, const char *name, int *lenp)
{
	struct property *pp;

	for (pp = np->properties; pp != 0; pp = pp->next)
		if (strcmp(pp->name, name) == 0) {
			if (lenp != 0)
				*lenp = pp->length;
			return pp->value;
		}
	return NULL;
}
EXPORT_SYMBOL(get_property);

/*
 * Add a property to a node
 */
void
prom_add_property(struct device_node* np, struct property* prop)
{
	struct property **next = &np->properties;

	prop->next = NULL;	
	while (*next)
		next = &(*next)->next;
	*next = prop;
}

#if 0
void
print_properties(struct device_node *np)
{
	struct property *pp;
	char *cp;
	int i, n;

	for (pp = np->properties; pp != 0; pp = pp->next) {
		printk(KERN_INFO "%s", pp->name);
		for (i = strlen(pp->name); i < 16; ++i)
			printk(" ");
		cp = (char *) pp->value;
		for (i = pp->length; i > 0; --i, ++cp)
			if ((i > 1 && (*cp < 0x20 || *cp > 0x7e))
			    || (i == 1 && *cp != 0))
				break;
		if (i == 0 && pp->length > 1) {
			/* looks like a string */
			printk(" %s\n", (char *) pp->value);
		} else {
			/* dump it in hex */
			n = pp->length;
			if (n > 64)
				n = 64;
			if (pp->length % 4 == 0) {
				unsigned int *p = (unsigned int *) pp->value;

				n /= 4;
				for (i = 0; i < n; ++i) {
					if (i != 0 && (i % 4) == 0)
						printk("\n                ");
					printk(" %08x", *p++);
				}
			} else {
				unsigned char *bp = pp->value;

				for (i = 0; i < n; ++i) {
					if (i != 0 && (i % 16) == 0)
						printk("\n                ");
					printk(" %02x", *bp++);
				}
			}
			printk("\n");
			if (pp->length > 64)
				printk("                 ... (length = %d)\n",
				       pp->length);
		}
	}
}
#endif