LXR linux/drivers/mtd/chips/chipreg.c

   1/*
   2 * Registration for chip drivers
   3 *
   4 */
   5
   6#include <linux/kernel.h>
   7#include <linux/module.h>
   8#include <linux/kmod.h>
   9#include <linux/spinlock.h>
  10#include <linux/slab.h>
  11#include <linux/mtd/map.h>
  12#include <linux/mtd/mtd.h>
  13
  14static DEFINE_SPINLOCK(chip_drvs_lock);
  15static LIST_HEAD(chip_drvs_list);
  16
  17void register_mtd_chip_driver(struct mtd_chip_driver *drv)
  18{
  19        spin_lock(&chip_drvs_lock);
  20        list_add(&drv->list, &chip_drvs_list);
  21        spin_unlock(&chip_drvs_lock);
  22}
  23
  24void unregister_mtd_chip_driver(struct mtd_chip_driver *drv)
  25{
  26        spin_lock(&chip_drvs_lock);
  27        list_del(&drv->list);
  28        spin_unlock(&chip_drvs_lock);
  29}
  30
  31static struct mtd_chip_driver *get_mtd_chip_driver (const char *name)
  32{
  33        struct list_head *pos;
  34        struct mtd_chip_driver *ret = NULL, *this;
  35
  36        spin_lock(&chip_drvs_lock);
  37
  38        list_for_each(pos, &chip_drvs_list) {
  39                this = list_entry(pos, typeof(*this), list);
  40
  41                if (!strcmp(this->name, name)) {
  42                        ret = this;
  43                        break;
  44                }
  45        }
  46        if (ret && !try_module_get(ret->module))
  47                ret = NULL;
  48
  49        spin_unlock(&chip_drvs_lock);
  50
  51        return ret;
  52}
  53
  54        /* Hide all the horrid details, like some silly person taking
  55           get_module_symbol() away from us, from the caller. */
  56
  57struct mtd_info *do_map_probe(const char *name, struct map_info *map)
  58{
  59        struct mtd_chip_driver *drv;
  60        struct mtd_info *ret;
  61
  62        drv = get_mtd_chip_driver(name);
  63
  64        if (!drv && !request_module("%s", name))
  65                drv = get_mtd_chip_driver(name);
  66
  67        if (!drv)
  68                return NULL;
  69
  70        ret = drv->probe(map);
  71
  72        /* We decrease the use count here. It may have been a
  73           probe-only module, which is no longer required from this
  74           point, having given us a handle on (and increased the use
  75           count of) the actual driver code.
  76        */
  77        module_put(drv->module);
  78
  79        return ret;
  80}
  81/*
  82 * Destroy an MTD device which was created for a map device.
  83 * Make sure the MTD device is already unregistered before calling this
  84 */
  85void map_destroy(struct mtd_info *mtd)
  86{
  87        struct map_info *map = mtd->priv;
  88
  89        if (map->fldrv->destroy)
  90                map->fldrv->destroy(mtd);
  91
  92        module_put(map->fldrv->module);
  93
  94        kfree(mtd);
  95}
  96
  97EXPORT_SYMBOL(register_mtd_chip_driver);
  98EXPORT_SYMBOL(unregister_mtd_chip_driver);
  99EXPORT_SYMBOL(do_map_probe);
 100EXPORT_SYMBOL(map_destroy);
 101
 102MODULE_LICENSE("GPL");
 103MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 104MODULE_DESCRIPTION("Core routines for registering and invoking MTD chip drivers");
 105