103 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Registration for chip drivers4 *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 taking53 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 a71 probe-only module, which is no longer required from this72 point, having given us a handle on (and increased the use73 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 this82 */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