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 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 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 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 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 */ 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