source: GPL/branches/uniaud32-next/lib32/devres.c@ 719

/*
 * 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 <linux/gfp.h>
#include <linux/errno.h>
#include <asm/io.h>

struct devres_node {
        struct list_head                entry;
        dr_release_t                    release;
        const char                      *name;
        size_t                          size;
};

struct devres {
        struct devres_node              node;
        /* -- 3 pointers */
        u8              data[]; /* guarantee ull alignment */
};

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

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

#define devres_log(dev, node, op)       do {} while (0)

/*
 * 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 inline struct devres * alloc_dr(dr_release_t release,
                                                size_t size, gfp_t gfp, int nid)
{
        size_t tot_size = sizeof(struct devres) + size;
        struct devres *dr;

        dr = kmalloc_node_track_caller(tot_size, gfp, nid);

        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);
}

/**
 * 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);
}

/**
 * __devres_alloc_node - Allocate device resource data
 * @release: Release function devres will be associated with
 * @size: Allocation size
 * @gfp: Allocation flags
 * @nid: NUMA node
 * @name: Name of the resource
 *
 * 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_node(dr_release_t release, size_t size, gfp_t gfp, int nid,
                          const char *name)
{
        struct devres *dr;

        dr = alloc_dr(release, size, gfp | __GFP_ZERO, nid);
        if (unlikely(!dr))
                return NULL;
        set_node_dbginfo(&dr->node, name, size);
        return dr->data;
}

/**
 * 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);
        }
}

#if 0 //2022-09-02
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);
        struct 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, struct devres) {
                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;

        /* Looks like an uninitialized device structure */
        if (WARN_ON(dev->devres_head.next == NULL))
                return -ENODEV;
        spin_lock_irqsave(&dev->devres_lock, flags);
        return release_nodes(dev, dev->devres_head.next, &dev->devres_head,
                             flags);
}
#endif

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_node) {
                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;
}

/*
 * Custom devres actions allow inserting a simple function call
 * into the teadown sequence.
 */

struct action_devres {
        void *data;
        void (*action)(void *);
};

static void devm_action_release(struct device *dev, void *res)
{
        struct action_devres *devres = res;

        devres->action(devres->data);
}

/**
 * devm_add_action() - add a custom action to list of managed resources
 * @dev: Device that owns the action
 * @action: Function that should be called
 * @data: Pointer to data passed to @action implementation
 *
 * This adds a custom action to the list of managed resources so that
 * it gets executed as part of standard resource unwinding.
 */
int devm_add_action(struct device *dev, void (*action)(void *), void *data)
{
        struct action_devres *devres;

        devres = devres_alloc(devm_action_release,
                              sizeof(struct action_devres), GFP_KERNEL);
        if (!devres)
                return -ENOMEM;

        devres->data = data;
        devres->action = action;

        devres_add(dev, devres);

        return 0;
}

/**
 * devm_remove_action() - removes previously added custom action
 * @dev: Device that owns the action
 * @action: Function implementing the action
 * @data: Pointer to data passed to @action implementation
 *
 * Removes instance of @action previously added by devm_add_action().
 * Both action and data should match one of the existing entries.
 */
void devm_remove_action(struct device *dev, void (*action)(void *), void *data)
{
}

/*
 * Managed kmalloc/kfree
 */
static void devm_kmalloc_release(struct device *dev, void *res)
{
        /* noop */
}

static int devm_kmalloc_match(struct device *dev, void *res, void *data)
{
        return res == data;
}

/**
 * devm_kmalloc - Resource-managed kmalloc
 * @dev: Device to allocate memory for
 * @size: Allocation size
 * @gfp: Allocation gfp flags
 *
 * Managed kmalloc.  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_kmalloc(struct device *dev, size_t size, gfp_t gfp)
{
        struct devres *dr;

        if (unlikely(!size))
                return ZERO_SIZE_PTR;

        /* use raw alloc_dr for kmalloc caller tracing */
        dr = alloc_dr(devm_kmalloc_release, size, gfp, dev_to_node(dev));
        if (unlikely(!dr))
                return NULL;

        /*
         * This is named devm_kzalloc_release for historical reasons
         * The initial implementation did not support kmalloc, only kzalloc
         */
        set_node_dbginfo(&dr->node, "devm_kzalloc_release", size);
        devres_add(dev, dr->data);
        return dr->data;
}
EXPORT_SYMBOL_GPL(devm_kmalloc);

enum devm_ioremap_type {
        DEVM_IOREMAP = 0,
        DEVM_IOREMAP_UC,
        DEVM_IOREMAP_WC,
        DEVM_IOREMAP_NP,
};

void devm_ioremap_release(struct device *dev, void *res)
{
        iounmap(*(void __iomem **)res);
}

static int devm_ioremap_match(struct device *dev, void *res, void *match_data)
{
        return *(void **)res == match_data;
}

static void *__devm_ioremap(struct device *dev, resource_size_t offset,
                                    resource_size_t size,
                                    enum devm_ioremap_type type)
{
        void __iomem **ptr, *addr = NULL;

        ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL);
        if (!ptr)
                return NULL;

        switch (type) {
        case DEVM_IOREMAP:
                addr = ioremap(offset, size);
                break;
#if 0
        case DEVM_IOREMAP_UC:
                addr = ioremap_uc(offset, size);
                break;
        case DEVM_IOREMAP_WC:
                addr = ioremap_wc(offset, size);
                break;
        case DEVM_IOREMAP_NP:
                addr = ioremap_np(offset, size);
                break;
#endif
        }

        if (addr) {
                *ptr = addr;
                devres_add(dev, ptr);
        } else
                devres_free(ptr);

        return addr;
}

/**
 * devm_ioremap - Managed ioremap()
 * @dev: Generic device to remap IO address for
 * @offset: Resource address to map
 * @size: Size of map
 *
 * Managed ioremap().  Map is automatically unmapped on driver detach.
 */
void __iomem *devm_ioremap(struct device *dev, resource_size_t offset,
                           resource_size_t size)
{
        return __devm_ioremap(dev, offset, size, DEVM_IOREMAP);
}
EXPORT_SYMBOL(devm_ioremap);