drivers/mtd/chips/chipreg.c

   1 /*
   2  * $Id: chipreg.c,v 1.16 2003/05/29 09:36:15 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 spinlock_t chip_drvs_lock = SPIN_LOCK_UNLOCKED;
  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 static int mtd_generic_point(struct mtd_info *mtd, loff_t from, size_t len,
  59         size_t *retlen, u_char **mtdbuf)
  60 {
  61         struct map_info *map = (struct map_info *) mtd->priv;
  62         *mtdbuf = (u_char *) (map->virt + ((int) from));
  63         *retlen = len;
  64         return(0);
  65 }
  66
  67 static void mtd_generic_unpoint (struct mtd_info *mtd, u_char *addr,
  68         loff_t from, size_t len)
  69 {
  70         /* I don't know what we should do here */
  71 }
  72
  73         /* Hide all the horrid details, like some silly person taking
  74            get_module_symbol() away from us, from the caller. */
  75
  76 struct mtd_info *do_map_probe(const char *name, struct map_info *map)
  77 {
  78         struct mtd_chip_driver *drv;
  79         struct mtd_info *ret;
  80
  81         drv = get_mtd_chip_driver(name);
  82
  83         if (!drv && !request_module("%s", name))
  84                 drv = get_mtd_chip_driver(name);
  85
  86         if (!drv)
  87                 return NULL;
  88
  89         ret = drv->probe(map);
  90
  91         /* We decrease the use count here. It may have been a
  92            probe-only module, which is no longer required from this
  93            point, having given us a handle on (and increased the use
  94            count of) the actual driver code.
  95         */
  96         module_put(drv->module);
  97
  98         if (ret) {
  99                 if (!ret->point)
 100                         ret->point = mtd_generic_point;
 101                 if (!ret->unpoint)
 102                         ret->unpoint = mtd_generic_unpoint;
 103                 return ret;
 104         }
 105
 106         return NULL;
 107 }
 108 /*
 109  * Destroy an MTD device which was created for a map device.
 110  * Make sure the MTD device is already unregistered before calling this
 111  */
 112 void map_destroy(struct mtd_info *mtd)
 113 {
 114         struct map_info *map = mtd->priv;
 115
 116         if (map->fldrv->destroy)
 117                 map->fldrv->destroy(mtd);
 118
 119         module_put(map->fldrv->module);
 120
 121         kfree(mtd);
 122 }
 123
 124 EXPORT_SYMBOL(register_mtd_chip_driver);
 125 EXPORT_SYMBOL(unregister_mtd_chip_driver);
 126 EXPORT_SYMBOL(do_map_probe);
 127 EXPORT_SYMBOL(map_destroy);
 128
 129 MODULE_LICENSE("GPL");
 130 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 131 MODULE_DESCRIPTION("Core routines for registering and invoking MTD chip drivers");