LXR linux/drivers/mtd/chips/chipreg.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Registration for chip drivers
   4 *
   5 */
   6
   7#include <linux/kernel.h>
   8#include <linux/module.h>
   9#include <linux/kmod.h>
  10#include <linux/spinlock.h>
  11#include <linux/slab.h>
  12#include <linux/mtd/map.h>
  13#include <linux/mtd/mtd.h>
  14
  15static DEFINE_SPINLOCK(chip_drvs_lock);
  16static LIST_HEAD(chip_drvs_list);
  17
  18void register_mtd_chip_driver(struct mtd_chip_driver *drv)
  19{
  20        spin_lock(&chip_drvs_lock);
  21        list_add(&drv->list, &chip_drvs_list);
  22        spin_unlock(&chip_drvs_lock);
  23}
  24
  25void unregister_mtd_chip_driver(struct mtd_chip_driver *drv)
  26{
  27        spin_lock(&chip_drvs_lock);
  28        list_del(&drv->list);
  29        spin_unlock(&chip_drvs_lock);
  30}
  31
  32static struct mtd_chip_driver *get_mtd_chip_driver (const char *name)
  33{
  34        struct mtd_chip_driver *ret = NULL, *this;
  35
  36        spin_lock(&chip_drvs_lock);
  37
  38        list_for_each_entry(this, &chip_drvs_list, list) {
  39                if (!strcmp(this->name, name)) {
  40                        ret = this;
  41                        break;
  42                }
  43        }
  44        if (ret && !try_module_get(ret->module))
  45                ret = NULL;
  46
  47        spin_unlock(&chip_drvs_lock);
  48
  49        return ret;
  50}
  51
  52        /* Hide all the horrid details, like some silly person taking
  53           get_module_symbol() away from us, from the caller. */
  54
  55struct mtd_info *do_map_probe(const char *name, struct map_info *map)
  56{
  57        struct mtd_chip_driver *drv;
  58        struct mtd_info *ret;
  59
  60        drv = get_mtd_chip_driver(name);
  61
  62        if (!drv && !request_module("%s", name))
  63                drv = get_mtd_chip_driver(name);
  64
  65        if (!drv)
  66                return NULL;
  67
  68        ret = drv->probe(map);
  69
  70        /* We decrease the use count here. It may have been a
  71           probe-only module, which is no longer required from this
  72           point, having given us a handle on (and increased the use
  73           count of) the actual driver code.
  74        */
  75        module_put(drv->module);
  76
  77        return ret;
  78}
  79/*
  80 * Destroy an MTD device which was created for a map device.
  81 * Make sure the MTD device is already unregistered before calling this
  82 */
  83void map_destroy(struct mtd_info *mtd)
  84{
  85        struct map_info *map = mtd->priv;
  86
  87        if (map->fldrv->destroy)
  88                map->fldrv->destroy(mtd);
  89
  90        module_put(map->fldrv->module);
  91
  92        kfree(mtd);
  93}
  94
  95EXPORT_SYMBOL(register_mtd_chip_driver);
  96EXPORT_SYMBOL(unregister_mtd_chip_driver);
  97EXPORT_SYMBOL(do_map_probe);
  98EXPORT_SYMBOL(map_destroy);
  99
 100MODULE_LICENSE("GPL");
 101MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 102MODULE_DESCRIPTION("Core routines for registering and invoking MTD chip drivers");
 103