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