chipreg.c

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/*
 * Registration for chip drivers
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/kmod.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/mtd/map.h>
#include <linux/mtd/mtd.h>

static DEFINE_SPINLOCK(chip_drvs_lock);
static LIST_HEAD(chip_drvs_list);

void register_mtd_chip_driver(struct mtd_chip_driver *drv)
{
    spin_lock(&chip_drvs_lock);
    list_add(&drv->list, &chip_drvs_list);
    spin_unlock(&chip_drvs_lock);
}

void unregister_mtd_chip_driver(struct mtd_chip_driver *drv)
{
    spin_lock(&chip_drvs_lock);
    list_del(&drv->list);
    spin_unlock(&chip_drvs_lock);
}

static struct mtd_chip_driver *get_mtd_chip_driver (const char *name)
{
    struct list_head *pos;
    struct mtd_chip_driver *ret = NULL, *this;

    spin_lock(&chip_drvs_lock);

    list_for_each(pos, &chip_drvs_list) {
        this = list_entry(pos, typeof(*this), list);

        if (!strcmp(this->name, name)) {
            ret = this;
            break;
        }
    }
    if (ret && !try_module_get(ret->module))
        ret = NULL;

    spin_unlock(&chip_drvs_lock);

    return ret;
}

    /* Hide all the horrid details, like some silly person taking
       get_module_symbol() away from us, from the caller. */

struct mtd_info *do_map_probe(const char *name, struct map_info *map)
{
    struct mtd_chip_driver *drv;
    struct mtd_info *ret;

    drv = get_mtd_chip_driver(name);

    if (!drv && !request_module("%s", name))
        drv = get_mtd_chip_driver(name);

    if (!drv)
        return NULL;

    ret = drv->probe(map);

    /* We decrease the use count here. It may have been a
       probe-only module, which is no longer required from this
       point, having given us a handle on (and increased the use
       count of) the actual driver code.
    */
    module_put(drv->module);

    return ret;
}
/*
 * Destroy an MTD device which was created for a map device.
 * Make sure the MTD device is already unregistered before calling this
 */
void map_destroy(struct mtd_info *mtd)
{
    struct map_info *map = mtd->priv;

    if (map->fldrv->destroy)
        map->fldrv->destroy(mtd);

    module_put(map->fldrv->module);

    kfree(mtd);
}

EXPORT_SYMBOL(register_mtd_chip_driver);
EXPORT_SYMBOL(unregister_mtd_chip_driver);
EXPORT_SYMBOL(do_map_probe);
EXPORT_SYMBOL(map_destroy);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Woodhouse <[email protected]>");
MODULE_DESCRIPTION("Core routines for registering and invoking MTD chip drivers");