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#include <linux/mtd/compatmac.h>
  14
  15static DEFINE_SPINLOCK(chip_drvs_lock);
  16static LIST_HEAD(chip_drvs_list);
  17
  18void register_mtd_chip_driver(struct mtd_chip_driver *drv)
  19{
  20        spin_lock(&chip_drvs_lock);
  21        list_add(&drv->list, &chip_drvs_list);
  22        spin_unlock(&chip_drvs_lock);
  23}
  24
  25void unregister_mtd_chip_driver(struct mtd_chip_driver *drv)
  26{
  27        spin_lock(&chip_drvs_lock);
  28        list_del(&drv->list);
  29        spin_unlock(&chip_drvs_lock);
  30}
  31
  32static struct mtd_chip_driver *get_mtd_chip_driver (const char *name)
  33{
  34        struct list_head *pos;
  35        struct mtd_chip_driver *ret = NULL, *this;
  36
  37        spin_lock(&chip_drvs_lock);
  38
  39        list_for_each(pos, &chip_drvs_list) {
  40                this = list_entry(pos, typeof(*this), list);
  41
  42                if (!strcmp(this->name, name)) {
  43                        ret = this;
  44                        break;
  45                }
  46        }
  47        if (ret && !try_module_get(ret->module))
  48                ret = NULL;
  49
  50        spin_unlock(&chip_drvs_lock);
  51
  52        return ret;
  53}
  54
  55        /* Hide all the horrid details, like some silly person taking
  56           get_module_symbol() away from us, from the caller. */
  57
  58struct mtd_info *do_map_probe(const char *name, struct map_info *map)
  59{
  60        struct mtd_chip_driver *drv;
  61        struct mtd_info *ret;
  62
  63        drv = get_mtd_chip_driver(name);
  64
  65        if (!drv && !request_module("%s", name))
  66                drv = get_mtd_chip_driver(name);
  67
  68        if (!drv)
  69                return NULL;
  70
  71        ret = drv->probe(map);
  72
  73        /* We decrease the use count here. It may have been a
  74           probe-only module, which is no longer required from this
  75           point, having given us a handle on (and increased the use
  76           count of) the actual driver code.
  77        */
  78        module_put(drv->module);
  79
  80        if (ret)
  81                return ret;
  82
  83        return NULL;
  84}
  85/*
  86 * Destroy an MTD device which was created for a map device.
  87 * Make sure the MTD device is already unregistered before calling this
  88 */
  89void map_destroy(struct mtd_info *mtd)
  90{
  91        struct map_info *map = mtd->priv;
  92
  93        if (map->fldrv->destroy)
  94                map->fldrv->destroy(mtd);
  95
  96        module_put(map->fldrv->module);
  97
  98        kfree(mtd);
  99}
 100
 101EXPORT_SYMBOL(register_mtd_chip_driver);
 102EXPORT_SYMBOL(unregister_mtd_chip_driver);
 103EXPORT_SYMBOL(do_map_probe);
 104EXPORT_SYMBOL(map_destroy);
 105
 106MODULE_LICENSE("GPL");
 107MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 108MODULE_DESCRIPTION("Core routines for registering and invoking MTD chip drivers");
 109