projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 2 | * Common code to handle absent "placeholder" devices | |
| 3 | * Copyright 2001 Resilience Corporation <ebrower@resilience.com> | |
| 1da177e4 LT |
4 | * |
| 5 | * This map driver is used to allocate "placeholder" MTD | |
| 1f948b43 TG |
6 | * devices on systems that have socketed/removable media. |
| 7 | * Use of this driver as a fallback preserves the expected | |
| 1da177e4 LT |
8 | * registration of MTD device nodes regardless of probe outcome. |
| 9 | * A usage example is as follows: | |
| 10 | * | |
| 11 | * my_dev[i] = do_map_probe("cfi", &my_map[i]); | |
| 12 | * if(NULL == my_dev[i]) { | |
| 13 | * my_dev[i] = do_map_probe("map_absent", &my_map[i]); | |
| 14 | * } | |
| 15 | * | |
| 16 | * Any device 'probed' with this driver will return -ENODEV | |
| 17 | * upon open. | |
| 18 | */ | |
| 19 | ||
| 20 | #include <linux/module.h> | |
| 21 | #include <linux/types.h> | |
| 22 | #include <linux/kernel.h> | |
| 23 | #include <linux/errno.h> | |
| 24 | #include <linux/slab.h> | |
| 25 | #include <linux/init.h> | |
| 26 | #include <linux/mtd/mtd.h> | |
| 27 | #include <linux/mtd/map.h> | |
| 1da177e4 LT |
28 | |
| 29 | static int map_absent_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *); | |
| 30 | static int map_absent_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *); | |
| 31 | static int map_absent_erase (struct mtd_info *, struct erase_info *); | |
| 32 | static void map_absent_sync (struct mtd_info *); | |
| 33 | static struct mtd_info *map_absent_probe(struct map_info *map); | |
| 34 | static void map_absent_destroy (struct mtd_info *); | |
| 35 | ||
| 36 | ||
| 37 | static struct mtd_chip_driver map_absent_chipdrv = { | |
| 38 | .probe = map_absent_probe, | |
| 39 | .destroy = map_absent_destroy, | |
| 40 | .name = "map_absent", | |
| 41 | .module = THIS_MODULE | |
| 42 | }; | |
| 43 | ||
| 44 | static struct mtd_info *map_absent_probe(struct map_info *map) | |
| 45 | { | |
| 46 | struct mtd_info *mtd; | |
| 47 | ||
| 95b93a0c | 48 | mtd = kzalloc(sizeof(*mtd), GFP_KERNEL); |
| 1da177e4 LT |
49 | if (!mtd) { |
| 50 | return NULL; | |
| 51 | } | |
| 52 | ||
| 1da177e4 LT |
53 | map->fldrv = &map_absent_chipdrv; |
| 54 | mtd->priv = map; | |
| 55 | mtd->name = map->name; | |
| 56 | mtd->type = MTD_ABSENT; | |
| 57 | mtd->size = map->size; | |
| 58 | mtd->erase = map_absent_erase; | |
| 59 | mtd->read = map_absent_read; | |
| 60 | mtd->write = map_absent_write; | |
| 61 | mtd->sync = map_absent_sync; | |
| 62 | mtd->flags = 0; | |
| 17ffc7ba AB |
63 | mtd->erasesize = PAGE_SIZE; |
| 64 | mtd->writesize = 1; | |
| 1da177e4 LT |
65 | |
| 66 | __module_get(THIS_MODULE); | |
| 67 | return mtd; | |
| 68 | } | |
| 69 | ||
| 70 | ||
| 71 | static int map_absent_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf) | |
| 72 | { | |
| 73 | *retlen = 0; | |
| 74 | return -ENODEV; | |
| 75 | } | |
| 76 | ||
| 77 | static int map_absent_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf) | |
| 78 | { | |
| 79 | *retlen = 0; | |
| 1f948b43 | 80 | return -ENODEV; |
| 1da177e4 LT |
81 | } |
| 82 | ||
| 83 | static int map_absent_erase(struct mtd_info *mtd, struct erase_info *instr) | |
| 84 | { | |
| 85 | return -ENODEV; | |
| 86 | } | |
| 87 | ||
| 88 | static void map_absent_sync(struct mtd_info *mtd) | |
| 89 | { | |
| 90 | /* nop */ | |
| 91 | } | |
| 92 | ||
| 93 | static void map_absent_destroy(struct mtd_info *mtd) | |
| 94 | { | |
| 95 | /* nop */ | |
| 96 | } | |
| 97 | ||
| 98 | static int __init map_absent_init(void) | |
| 99 | { | |
| 100 | register_mtd_chip_driver(&map_absent_chipdrv); | |
| 101 | return 0; | |
| 102 | } | |
| 103 | ||
| 104 | static void __exit map_absent_exit(void) | |
| 105 | { | |
| 106 | unregister_mtd_chip_driver(&map_absent_chipdrv); | |
| 107 | } | |
| 108 | ||
| 109 | module_init(map_absent_init); | |
| 110 | module_exit(map_absent_exit); | |
| 111 | ||
| 112 | MODULE_LICENSE("GPL"); | |
| 113 | MODULE_AUTHOR("Resilience Corporation - Eric Brower <ebrower@resilience.com>"); | |
| 114 | MODULE_DESCRIPTION("Placeholder MTD chip driver for 'absent' chips"); |