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