path: root/drivers/base/devres.c

/*
 * drivers/base/devres.c - device resource management
 *
 * Copyright (c) 2006  SUSE Linux Products GmbH
 * Copyright (c) 2006  Tejun Heo <teheo@suse.de>
 *
 * This file is released under the GPLv2.
 */

#include <linux/device.h>
#include <linux/module.h>
#include <linux/slab.h>

#include "base.h"

struct devres_node {
	struct list_head		entry;
	dr_release_t			release;
#ifdef CONFIG_DEBUG_DEVRES
	const char			*name;
	size_t				size;
#endif
};

struct devres {
	struct devres_node		node;
	/* -- 3 pointers */
	unsigned long long		data[];	/* guarantee ull alignment */
};

struct devres_group {
	struct devres_node		node[2];
	void				*id;
	int				color;
	/* -- 8 pointers */
};

#ifdef CONFIG_DEBUG_DEVRES
static int log_devres = 0;
module_param_named(log, log_devres, int, S_IRUGO | S_IWUSR);

static void set_node_dbginfo(struct devres_node *node, const char *name,
			     size_t size)
{
	node->name = name;
	node->size = size;
}

static void devres_log(struct device *dev, struct devres_node *node,
		       const char *op)
{
	if (unlikely(log_devres))
		dev_err(dev, "DEVRES %3s %p %s (%lu bytes)\n",
			op, node, node->name, (unsigned long)node->size);
}
#else /* CONFIG_DEBUG_DEVRES */
#define set_node_dbginfo(node, n, s)	do {} while (0)
#define devres_log(dev, node, op)	do {} while (0)
#endif /* CONFIG_DEBUG_DEVRES */

/*
 * Release functions for devres group.  These callbacks are used only
 * for identification.
 */
static void group_open_release(struct device *dev, void *res)
{
	/* noop */
}

static void group_close_release(struct device *dev, void *res)
{
	/* noop */
}

static struct devres_group * node_to_group(struct devres_node *node)
{
	if (node->release == &group_open_release)
		return container_of(node, struct devres_group, node[0]);
	if (node->release == &group_close_release)
		return container_of(node, struct devres_group, node[1]);
	return NULL;
}

static __always_inline struct devres * alloc_dr(dr_release_t release,
						size_t size, gfp_t gfp)
{
	size_t tot_size = sizeof(struct devres) + size;
	struct devres *dr;

	dr = kmalloc_track_caller(tot_size, gfp);
	if (unlikely(!dr))
		return NULL;

	memset(dr, 0, offsetof(struct devres, data));

	INIT_LIST_HEAD(&dr->node.entry);
	dr->node.release = release;
	return dr;
}

static void add_dr(struct device *dev, struct devres_node *node)
{
	devres_log(dev, node, "ADD");
	BUG_ON(!list_empty(&node->entry));
	list_add_tail(&node->entry, &dev->devres_head);
}

#ifdef CONFIG_DEBUG_DEVRES
void * __devres_alloc(dr_release_t release, size_t size, gfp_t gfp,
		      const char *name)
{
	struct devres *dr;

	dr = alloc_dr(release, size, gfp | __GFP_ZERO);
	if (unlikely(!dr))
		return NULL;
	set_node_dbginfo(&dr->node, name, size);
	return dr->data;
}
EXPORT_SYMBOL_GPL(__devres_alloc);
#else
/**
 * devres_alloc - Allocate device resource data
 * @release: Release function devres will be associated with
 * @size: Allocation size
 * @gfp: Allocation flags
 *
 * Allocate devres of @size bytes.  The allocated area is zeroed, then
 * associated with @release.  The returned pointer can be passed to
 * other devres_*() functions.
 *
 * RETURNS:
 * Pointer to allocated devres on success, NULL on failure.
 */
void * devres_alloc(dr_release_t release, size_t size, gfp_t gfp)
{
	struct devres *dr;

	dr = alloc_dr(release, size, gfp | __GFP_ZERO);
	if (unlikely(!dr))
		return NULL;
	return dr->data;
}
EXPORT_SYMBOL_GPL(devres_alloc);
#endif

/**
 * devres_for_each_res - Resource iterator
 * @dev: Device to iterate resource from
 * @release: Look for resources associated with this release function
 * @match: Match function (optional)
 * @match_data: Data for the match function
 * @fn: Function to be called for each matched resource.
 * @data: Data for @fn, the 3rd parameter of @fn
 *
 * Call @fn for each devres of @dev which is associated with @release
 * and for which @match returns 1.
 *
 * RETURNS:
 * 	void
 */
void devres_for_each_res(struct device *dev, dr_release_t release,
			dr_match_t match, void *match_data,
			void (*fn)(struct device *, void *, void *),
			void *data)
{
	struct devres_node *node;
	struct devres_node *tmp;
	unsigned long flags;

	if (!fn)
		return;

	spin_lock_irqsave(&dev->devres_lock, flags);
	list_for_each_entry_safe_reverse(node, tmp,
			&dev->devres_head, entry) {
		struct devres *dr = container_of(node, struct devres, node);

		if (node->release != release)
			continue;
		if (