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