release/src-rt-6.x.4708/linux/linux-2.6.36/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
  14 static DEFINE_SPINLOCK(chip_drvs_lock);
  15 static LIST_HEAD(chip_drvs_list);
  16
  17 void 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
  24 void 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
  31 static 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
  57 struct 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         if (ret)
  80                 return ret;
  81
  82         return NULL;
  83 }
  84 /*
  85  * Destroy an MTD device which was created for a map device.
  86  * Make sure the MTD device is already unregistered before calling this
  87  */
  88 void map_destroy(struct mtd_info *mtd)
  89 {
  90         struct map_info *map = mtd->priv;
  91
  92         if (map->fldrv->destroy)
  93                 map->fldrv->destroy(mtd);
  94
  95         module_put(map->fldrv->module);
  96
  97         kfree(mtd);
  98 }
  99
 100 EXPORT_SYMBOL(register_mtd_chip_driver);
 101 EXPORT_SYMBOL(unregister_mtd_chip_driver);
 102 EXPORT_SYMBOL(do_map_probe);
 103 EXPORT_SYMBOL(map_destroy);
 104
 105 MODULE_LICENSE("GPL");
 106 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 107 MODULE_DESCRIPTION("Core routines for registering and invoking MTD chip drivers");