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
15 static DEFINE_SPINLOCK(chip_drvs_lock);
16 static LIST_HEAD(chip_drvs_list);
17
register_mtd_chip_driver(struct mtd_chip_driver * drv)18 void 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
unregister_mtd_chip_driver(struct mtd_chip_driver * drv)25 void 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
get_mtd_chip_driver(const char * name)32 static struct mtd_chip_driver *get_mtd_chip_driver (const char *name)
33 {
34 struct list_head *pos;
35 struct mtd_chip_driver *ret = NULL, *this;
36
37 spin_lock(&chip_drvs_lock);
38
39 list_for_each(pos, &chip_drvs_list) {
40 this = list_entry(pos, typeof(*this), list);
41
42 if (!strcmp(this->name, name)) {
43 ret = this;
44 break;
45 }
46 }
47 if (ret && !try_module_get(ret->module))
48 ret = NULL;
49
50 spin_unlock(&chip_drvs_lock);
51
52 return ret;
53 }
54
55 /* Hide all the horrid details, like some silly person taking
56 get_module_symbol() away from us, from the caller. */
57
do_map_probe(const char * name,struct map_info * map)58 struct mtd_info *do_map_probe(const char *name, struct map_info *map)
59 {
60 struct mtd_chip_driver *drv;
61 struct mtd_info *ret;
62
63 drv = get_mtd_chip_driver(name);
64
65 if (!drv && !request_module("%s", name))
66 drv = get_mtd_chip_driver(name);
67
68 if (!drv)
69 return NULL;
70
71 ret = drv->probe(map);
72
73 /* We decrease the use count here. It may have been a
74 probe-only module, which is no longer required from this
75 point, having given us a handle on (and increased the use
76 count of) the actual driver code.
77 */
78 module_put(drv->module);
79
80 return ret;
81 }
82 /*
83 * Destroy an MTD device which was created for a map device.
84 * Make sure the MTD device is already unregistered before calling this
85 */
map_destroy(struct mtd_info * mtd)86 void map_destroy(struct mtd_info *mtd)
87 {
88 struct map_info *map = mtd->priv;
89
90 if (map->fldrv->destroy)
91 map->fldrv->destroy(mtd);
92
93 module_put(map->fldrv->module);
94
95 kfree(mtd);
96 }
97
98 EXPORT_SYMBOL(register_mtd_chip_driver);
99 EXPORT_SYMBOL(unregister_mtd_chip_driver);
100 EXPORT_SYMBOL(do_map_probe);
101 EXPORT_SYMBOL(map_destroy);
102
103 MODULE_LICENSE("GPL");
104 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
105 MODULE_DESCRIPTION("Core routines for registering and invoking MTD chip drivers");
106