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/module.h>
  10 #include <linux/kmod.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/slab.h>
  13 #include <linux/mtd/map.h>
  14 #include <linux/mtd/mtd.h>
  15 #include <linux/mtd/compatmac.h>
  16
  17 static DEFINE_SPINLOCK(chip_drvs_lock);
  18 static LIST_HEAD(chip_drvs_list);
  19
  20 void register_mtd_chip_driver(struct mtd_chip_driver *drv)
  21 {
  22         spin_lock(&chip_drvs_lock);
  23         list_add(&drv->list, &chip_drvs_list);
  24         spin_unlock(&chip_drvs_lock);
  25 }
  26
  27 void unregister_mtd_chip_driver(struct mtd_chip_driver *drv)
  28 {
  29         spin_lock(&chip_drvs_lock);
  30         list_del(&drv->list);
  31         spin_unlock(&chip_drvs_lock);
  32 }
  33
  34 static struct mtd_chip_driver *get_mtd_chip_driver (const char *name)
  35 {
  36         struct list_head *pos;
  37         struct mtd_chip_driver *ret = NULL, *this;
  38
  39         spin_lock(&chip_drvs_lock);
  40
  41         list_for_each(pos, &chip_drvs_list) {
  42                 this = list_entry(pos, typeof(*this), list);
  43
  44                 if (!strcmp(this->name, name)) {
  45                         ret = this;
  46                         break;
  47                 }
  48         }
  49         if (ret && !try_module_get(ret->module))
  50                 ret = NULL;
  51
  52         spin_unlock(&chip_drvs_lock);
  53
  54         return ret;
  55 }
  56
  57 static int mtd_generic_point(struct mtd_info *mtd, loff_t from, size_t len,
  58         size_t *retlen, u_char **mtdbuf)
  59 {
  60         struct map_info *map = (struct map_info *) mtd->priv;
  61         *mtdbuf = (u_char *) (map->virt + ((int) from));
  62         *retlen = len;
  63         return(0);
  64 }
  65
  66 static void mtd_generic_unpoint (struct mtd_info *mtd, u_char *addr,
  67         loff_t from, size_t len)
  68 {
  69         /* I don't know what we should do here */
  70 }
  71
  72         /* Hide all the horrid details, like some silly person taking
  73            get_module_symbol() away from us, from the caller. */
  74
  75 struct mtd_info *do_map_probe(const char *name, struct map_info *map)
  76 {
  77         struct mtd_chip_driver *drv;
  78         struct mtd_info *ret;
  79
  80         drv = get_mtd_chip_driver(name);
  81
  82         if (!drv && !request_module("%s", name))
  83                 drv = get_mtd_chip_driver(name);
  84
  85         if (!drv)
  86                 return NULL;
  87
  88         ret = drv->probe(map);
  89
  90         /* We decrease the use count here. It may have been a
  91            probe-only module, which is no longer required from this
  92            point, having given us a handle on (and increased the use
  93            count of) the actual driver code.
  94         */
  95         module_put(drv->module);
  96
  97         if (ret) {
  98                 if (!ret->point)
  99                         ret->point = mtd_generic_point;
 100                 if (!ret->unpoint)
 101                         ret->unpoint = mtd_generic_unpoint;
 102                 return ret;
 103         }
 104
 105         return NULL;
 106 }
 107 /*
 108  * Destroy an MTD device which was created for a map device.
 109  * Make sure the MTD device is already unregistered before calling this
 110  */
 111 void map_destroy(struct mtd_info *mtd)
 112 {
 113         struct map_info *map = mtd->priv;
 114
 115         if (map->fldrv->destroy)
 116                 map->fldrv->destroy(mtd);
 117
 118         module_put(map->fldrv->module);
 119
 120         kfree(mtd);
 121 }
 122
 123 EXPORT_SYMBOL(register_mtd_chip_driver);
 124 EXPORT_SYMBOL(unregister_mtd_chip_driver);
 125 EXPORT_SYMBOL(do_map_probe);
 126 EXPORT_SYMBOL(map_destroy);
 127
 128 MODULE_LICENSE("GPL");
 129 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 130 MODULE_DESCRIPTION("Core routines for registering and invoking MTD chip drivers");