drivers/mtd/chips/chipreg.c

   1 /*
   2  * $Id: chipreg.c,v 1.17 2004/11/16 18:29:00 dwmw2 Exp $
   3  *
   4  * Registration for chip drivers
   5  *
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/config.h>
  10 #include <linux/module.h>
  11 #include <linux/kmod.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/slab.h>
  14 #include <linux/mtd/map.h>
  15 #include <linux/mtd/mtd.h>
  16 #include <linux/mtd/compatmac.h>
  17
  18 static DEFINE_SPINLOCK(chip_drvs_lock);
  19 static LIST_HEAD(chip_drvs_list);
  20
  21 void register_mtd_chip_driver(struct mtd_chip_driver *drv)
  22 {
  23         spin_lock(&chip_drvs_lock);
  24         list_add(&drv->list, &chip_drvs_list);
  25         spin_unlock(&chip_drvs_lock);
  26 }
  27
  28 void unregister_mtd_chip_driver(struct mtd_chip_driver *drv)
  29 {
  30         spin_lock(&chip_drvs_lock);
  31         list_del(&drv->list);
  32         spin_unlock(&chip_drvs_lock);
  33 }
  34
  35 static struct mtd_chip_driver *get_mtd_chip_driver (const char *name)
  36 {
  37         struct list_head *pos;
  38         struct mtd_chip_driver *ret = NULL, *this;
  39
  40         spin_lock(&chip_drvs_lock);
  41
  42         list_for_each(pos, &chip_drvs_list) {
  43                 this = list_entry(pos, typeof(*this), list);
  44
  45                 if (!strcmp(this->name, name)) {
  46                         ret = this;
  47                         break;
  48                 }
  49         }
  50         if (ret && !try_module_get(ret->module))
  51                 ret = NULL;
  52
  53         spin_unlock(&chip_drvs_lock);
  54
  55         return ret;
  56 }
  57
  58         /* Hide all the horrid details, like some silly person taking
  59            get_module_symbol() away from us, from the caller. */
  60
  61 struct mtd_info *do_map_probe(const char *name, struct map_info *map)
  62 {
  63         struct mtd_chip_driver *drv;
  64         struct mtd_info *ret;
  65
  66         drv = get_mtd_chip_driver(name);
  67
  68         if (!drv && !request_module("%s", name))
  69                 drv = get_mtd_chip_driver(name);
  70
  71         if (!drv)
  72                 return NULL;
  73
  74         ret = drv->probe(map);
  75
  76         /* We decrease the use count here. It may have been a
  77            probe-only module, which is no longer required from this
  78            point, having given us a handle on (and increased the use
  79            count of) the actual driver code.
  80         */
  81         module_put(drv->module);
  82
  83         if (ret)
  84                 return ret;
  85
  86         return NULL;
  87 }
  88 /*
  89  * Destroy an MTD device which was created for a map device.
  90  * Make sure the MTD device is already unregistered before calling this
  91  */
  92 void map_destroy(struct mtd_info *mtd)
  93 {
  94         struct map_info *map = mtd->priv;
  95
  96         if (map->fldrv->destroy)
  97                 map->fldrv->destroy(mtd);
  98
  99         module_put(map->fldrv->module);
 100
 101         kfree(mtd);
 102 }
 103
 104 EXPORT_SYMBOL(register_mtd_chip_driver);
 105 EXPORT_SYMBOL(unregister_mtd_chip_driver);
 106 EXPORT_SYMBOL(do_map_probe);
 107 EXPORT_SYMBOL(map_destroy);
 108
 109 MODULE_LICENSE("GPL");
 110 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 111 MODULE_DESCRIPTION("Core routines for registering and invoking MTD chip drivers");