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/*

 * 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 "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_printk(KERN_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, tot_size);

        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);

        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);

        if (unlikely(!dr))

                return NULL;

        return dr->data;

}

EXPORT_SYMBOL_GPL(devres_alloc);

#endif

/**

 * devres_free - Free device resource data

 * @res: Pointer to devres data to free

 *

 * Free devres created with devres_alloc().

 */

void devres_free(void *res)

{

        if (res) {

                struct devres *dr = container_of(res, struct devres, data);

                BUG_ON(!list_empty(&dr->node.entry));

                kfree(dr);

        }

}

EXPORT_SYMBOL_GPL(devres_free);

/**

 * devres_add - Register device resource

 * @dev: Device to add resource to

 * @res: Resource to register

 *

 * Register devres @res to @dev.  @res should have been allocated

 * using devres_alloc().  On driver detach, the associated release

 * function will be invoked and devres will be freed automatically.

 */

void devres_add(struct device *dev, void *res)

{

        struct devres *dr = container_of(res, struct devres, data);

        unsigned long flags;

        spin_lock_irqsave(&dev->devres_lock, flags);

        add_dr(dev, &dr->node);

        spin_unlock_irqrestore(&dev->devres_lock, flags);

}

EXPORT_SYMBOL_GPL(devres_add);

static struct devres *find_dr(struct device *dev, dr_release_t release,

                              dr_match_t match, void *match_data)

{

        struct devres_node *node;

        list_for_each_entry_reverse(node, &dev->devres_head, entry) {

                struct devres *dr = container_of(node, struct devres, node);

                if (node->release != release)

                        continue;

                if (match && !match(dev, dr->data, match_data))

                        continue;

                return dr;

        }

        return NULL;

}

/**

 * devres_find - Find device resource

 * @dev: Device to lookup resource from

 * @release: Look for resources associated with this release function

 * @match: Match function (optional)

 * @match_data: Data for the match function

 *

 * Find the latest devres of @dev which is associated with @release

 * and for which @match returns 1.  If @match is NULL, it's considered

 * to match all.

 *

 * RETURNS:

 * Pointer to found devres, NULL if not found.

 */

void * devres_find(struct device *dev, dr_release_t release,

                   dr_match_t match, void *match_data)

{

        struct devres *dr;

        unsigned long flags;

        spin_lock_irqsave(&dev->devres_lock, flags);

        dr = find_dr(dev, release, match, match_data);

        spin_unlock_irqrestore(&dev->devres_lock, flags);

        if (dr)

                return dr->data;

        return NULL;

}

EXPORT_SYMBOL_GPL(devres_find);

/**

 * devres_get - Find devres, if non-existent, add one atomically

 * @dev: Device to lookup or add devres for

 * @new_res: Pointer to new initialized devres to add if not found

 * @match: Match function (optional)

 * @match_data: Data for the match function

 *

 * Find the latest devres of @dev which has the same release function

 * as @new_res and for which @match return 1.  If found, @new_res is

 * freed; otherwise, @new_res is added atomically.

 *

 * RETURNS:

 * Pointer to found or added devres.

 */

void * devres_get(struct device *dev, void *new_res,

                  dr_match_t match, void *match_data)

{

        struct devres *new_dr = container_of(new_res, struct devres, data);

        struct devres *dr;

        unsigned long flags;

        spin_lock_irqsave(&dev->devres_lock, flags);

        dr = find_dr(dev, new_dr->node.release, match, match_data);

        if (!dr) {

                add_dr(dev, &new_dr->node);

                dr = new_dr;

                new_dr = NULL;

        }

        spin_unlock_irqrestore(&dev->devres_lock, flags);

        devres_free(new_dr);

        return dr->data;

}

EXPORT_SYMBOL_GPL(devres_get);

/**

 * devres_remove - Find a device resource and remove it

 * @dev: Device to find resource from

 * @release: Look for resources associated with this release function

 * @match: Match function (optional)

 * @match_data: Data for the match function

 *

 * Find the latest devres of @dev associated with @release and for

 * which @match returns 1.  If @match is NULL, it's considered to

 * match all.  If found, the resource is removed atomically and

 * returned.

 *

 * RETURNS:

 * Pointer to removed devres on success, NULL if not found.

 */

void * devres_remove(struct device *dev, dr_release_t release,

                     dr_match_t match, void *match_data)

{

        struct devres *dr;

        unsigned long flags;

        spin_lock_irqsave(&dev->devres_lock, flags);

        dr = find_dr(dev, release, match, match_data);

        if (dr) {

                list_del_init(&dr->node.entry);

                devres_log(dev, &dr->node, "REM");

        }

        spin_unlock_irqrestore(&dev->devres_lock, flags);

        if (dr)

                return dr->data;

        return NULL;

}

EXPORT_SYMBOL_GPL(devres_remove);

/**

 * devres_destroy - Find a device resource and destroy it

 * @dev: Device to find resource from

 * @release: Look for resources associated with this release function

 * @match: Match function (optional)

 * @match_data: Data for the match function

 *

 * Find the latest devres of @dev associated with @release and for

 * which @match returns 1.  If @match is NULL, it's considered to

 * match all.  If found, the resource is removed atomically and freed.

 *

 * RETURNS:

 * 0 if devres is found and freed, -ENOENT if not found.

 */

int devres_destroy(struct device *dev, dr_release_t release,

                   dr_match_t match, void *match_data)

{

        void *res;

        res = devres_remove(dev, release, match, match_data);

        if (unlikely(!res))

                return -ENOENT;

        devres_free(res);

        return 0;

}

EXPORT_SYMBOL_GPL(devres_destroy);

static int remove_nodes(struct device *dev,

                        struct list_head *first, struct list_head *end,

                        struct list_head *todo)

{

        int cnt = 0, nr_groups = 0;

        struct list_head *cur;

        /* First pass - move normal devres entries to @todo and clear

         * devres_group colors.

         */

        cur = first;

        while (cur != end) {

                struct devres_node *node;

                struct devres_group *grp;

                node = list_entry(cur, struct devres_node, entry);

                cur = cur->next;

                grp = node_to_group(node);

                if (grp) {

                        /* clear color of group markers in the first pass */

                        grp->color = 0;

                        nr_groups++;

                } else {

                        /* regular devres entry */

                        if (&node->entry == first)

                                first = first->next;

                        list_move_tail(&node->entry, todo);

                        cnt++;

                }

        }

        if (!nr_groups)

                return cnt;

        /* Second pass - Scan groups and color them.  A group gets

         * color value of two iff the group is wholly contained in

         * [cur, end).  That is, for a closed group, both opening and

         * closing markers should be in the range, while just the

         * opening marker is enough for an open group.

         */

        cur = first;

        while (cur != end) {

                struct devres_node *node;

                struct devres_group *grp;

                node = list_entry(cur, struct devres_node, entry);

                cur = cur->next;

                grp = node_to_group(node);

                BUG_ON(!grp || list_empty(&grp->node[0].entry));

                grp->color++;

                if (list_empty(&grp->node[1].entry))

                        grp->color++;

                BUG_ON(grp->color <= 0 || grp->color > 2);

                if (grp->color == 2) {

                        /* No need to update cur or end.  The removed

                         * nodes are always before both.

                         */

                        list_move_tail(&grp->node[0].entry, todo);

                        list_del_init(&grp->node[1].entry);

                }

        }

        return cnt;

}

static int release_nodes(struct device *dev, struct list_head *first,

                         struct list_head *end, unsigned long flags)

{

        LIST_HEAD(todo);

        int cnt;

        struct devres *dr, *tmp;

        cnt = remove_nodes(dev, first, end, &todo);

        spin_unlock_irqrestore(&dev->devres_lock, flags);

        /* Release.  Note that both devres and devres_group are

         * handled as devres in the following loop.  This is safe.

         */

        list_for_each_entry_safe_reverse(dr, tmp, &todo, node.entry) {

                devres_log(dev, &dr->node, "REL");

                dr->node.release(dev, dr->data);

                kfree(dr);

        }

        return cnt;

}

/**

 * devres_release_all - Release all managed resources

 * @dev: Device to release resources for

 *

 * Release all resources associated with @dev.  This function is

 * called on driver detach.

 */

int devres_release_all(struct device *dev)

{

        unsigned long flags;

        spin_lock_irqsave(&dev->devres_lock, flags);

        return release_nodes(dev, dev->devres_head.next, &dev->devres_head,

                             flags);

}

/**

 * devres_open_group - Open a new devres group

 * @dev: Device to open devres group for

 * @id: Separator ID

 * @gfp: Allocation flags

 *

 * Open a new devres group for @dev with @id.  For @id, using a

 * pointer to an object which won't be used for another group is

 * recommended.  If @id is NULL, address-wise unique ID is created.

 *

 * RETURNS:

 * ID of the new group, NULL on failure.

 */

void * devres_open_group(struct device *dev, void *id, gfp_t gfp)

{

        struct devres_group *grp;

        unsigned long flags;

        grp = kmalloc(sizeof(*grp), gfp);

        if (unlikely(!grp))

                return NULL;

        grp->node[0].release = &group_open_release;

        grp->node[1].release = &group_close_release;

        INIT_LIST_HEAD(&grp->node[0].entry);

        INIT_LIST_HEAD(&grp->node[1].entry);

        set_node_dbginfo(&grp->node[0], "grp<", 0);

        set_node_dbginfo(&grp->node[1], "grp>", 0);

        grp->id = grp;

        if (id)

                grp->id = id;

        spin_lock_irqsave(&dev->devres_lock, flags);

        add_dr(dev, &grp->node[0]);

        spin_unlock_irqrestore(&dev->devres_lock, flags);

        return grp->id;

}

EXPORT_SYMBOL_GPL(devres_open_group);

/* Find devres group with ID @id.  If @id is NULL, look for the latest. */

static struct devres_group * find_group(struct device *dev, void *id)

{

        struct devres_node *node;

        list_for_each_entry_reverse(node, &dev->devres_head, entry) {

                struct devres_group *grp;

                if (node->release != &group_open_release)

                        continue;

                grp = container_of(node, struct devres_group, node[0]);

                if (id) {

                        if (grp->id == id)

                                return grp;

                } else if (list_empty(&grp->node[1].entry))

                        return grp;

        }

        return NULL;

}

/**

 * devres_close_group - Close a devres group

 * @dev: Device to close devres group for

 * @id: ID of target group, can be NULL

 *

 * Close the group identified by @id.  If @id is NULL, the latest open

 * group is selected.

 */

void devres_close_group(struct device *dev, void *id)

{

        struct devres_group *grp;

        unsigned long flags;

        spin_lock_irqsave(&dev->devres_lock, flags);

        grp = find_group(dev, id);

        if (grp)

                add_dr(dev, &grp->node[1]);

        else

                WARN_ON(1);

        spin_unlock_irqrestore(&dev->devres_lock, flags);

}

EXPORT_SYMBOL_GPL(devres_close_group);

/**

 * devres_remove_group - Remove a devres group

 * @dev: Device to remove group for

 * @id: ID of target group, can be NULL

 *

 * Remove the group identified by @id.  If @id is NULL, the latest

 * open group is selected.  Note that removing a group doesn't affect

 * any other resources.

 */

void devres_remove_group(struct device *dev, void *id)

{

        struct devres_group *grp;

        unsigned long flags;

        spin_lock_irqsave(&dev->devres_lock, flags);

        grp = find_group(dev, id);

        if (grp) {

                list_del_init(&grp->node[0].entry);

                list_del_init(&grp->node[1].entry);

                devres_log(dev, &grp->node[0], "REM");

        } else

                WARN_ON(1);

        spin_unlock_irqrestore(&dev->devres_lock, flags);

        kfree(grp);

}

EXPORT_SYMBOL_GPL(devres_remove_group);

/**

 * devres_release_group - Release resources in a devres group

 * @dev: Device to release group for

 * @id: ID of target group, can be NULL

 *

 * Release all resources in the group identified by @id.  If @id is

 * NULL, the latest open group is selected.  The selected group and

 * groups properly nested inside the selected group are removed.

 *

 * RETURNS:

 * The number of released non-group resources.

 */

int devres_release_group(struct device *dev, void *id)

{

        struct devres_group *grp;

        unsigned long flags;

        int cnt = 0;

        spin_lock_irqsave(&dev->devres_lock, flags);

        grp = find_group(dev, id);

        if (grp) {

                struct list_head *first = &grp->node[0].entry;

                struct list_head *end = &dev->devres_head;

                if (!list_empty(&grp->node[1].entry))

                        end = grp->node[1].entry.next;

                cnt = release_nodes(dev, first, end, flags);

        } else {

                WARN_ON(1);

                spin_unlock_irqrestore(&dev->devres_lock, flags);

        }

        return cnt;

}

EXPORT_SYMBOL_GPL(devres_release_group);

/*

 * Managed kzalloc/kfree

 */

static void devm_kzalloc_release(struct device *dev, void *res)

{

        /* noop */

}

static int devm_kzalloc_match(struct device *dev, void *res, void *data)

{

        return res == data;

}

/**

 * devm_kzalloc - Resource-managed kzalloc

 * @dev: Device to allocate memory for

 * @size: Allocation size

 * @gfp: Allocation gfp flags

 *

 * Managed kzalloc.  Memory allocated with this function is

 * automatically freed on driver detach.  Like all other devres

 * resources, guaranteed alignment is unsigned long long.

 *

 * RETURNS:

 * Pointer to allocated memory on success, NULL on failure.

 */

void * devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)

{

        struct devres *dr;

        /* use raw alloc_dr for kmalloc caller tracing */

        dr = alloc_dr(devm_kzalloc_release, size, gfp);

        if (unlikely(!dr))

                return NULL;

        set_node_dbginfo(&dr->node, "devm_kzalloc_release", size);

        devres_add(dev, dr->data);

        return dr->data;

}

EXPORT_SYMBOL_GPL(devm_kzalloc);

/**

 * devm_kfree - Resource-managed kfree

 * @dev: Device this memory belongs to

 * @p: Memory to free

 *

 * Free memory allocated with dev_kzalloc().

 */

void devm_kfree(struct device *dev, void *p)

{

        int rc;

        rc = devres_destroy(dev, devm_kzalloc_release, devm_kzalloc_match, p);

        WARN_ON(rc);

}

EXPORT_SYMBOL_GPL(devm_kfree);