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133 lines · 3.1 KiB

1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Common code to handle map devices which are simple ROM
4 * (C) 2000 Red Hat.
5 */
6
7#include <linux/module.h>
8#include <linux/types.h>
9#include <linux/kernel.h>
10#include <asm/io.h>
11#include <asm/byteorder.h>
12#include <linux/errno.h>
13#include <linux/slab.h>
14#include <linux/init.h>
15#include <linux/of.h>
16#include <linux/mtd/mtd.h>
17#include <linux/mtd/map.h>
18
19static int maprom_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
20static int maprom_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
21static void maprom_nop (struct mtd_info *);
22static struct mtd_info *map_rom_probe(struct map_info *map);
23static int maprom_erase (struct mtd_info *mtd, struct erase_info *info);
24static int maprom_point (struct mtd_info *mtd, loff_t from, size_t len,
25 size_t *retlen, void **virt, resource_size_t *phys);
26static int maprom_unpoint(struct mtd_info *mtd, loff_t from, size_t len);
27
28
29static struct mtd_chip_driver maprom_chipdrv = {
30 .probe = map_rom_probe,
31 .name = "map_rom",
32 .module = THIS_MODULE
33};
34
35static unsigned int default_erasesize(struct map_info *map)
36{
37 const __be32 *erase_size = NULL;
38
39 erase_size = of_get_property(map->device_node, "erase-size", NULL);
40
41 return !erase_size ? map->size : be32_to_cpu(*erase_size);
42}
43
44static struct mtd_info *map_rom_probe(struct map_info *map)
45{
46 struct mtd_info *mtd;
47
48 mtd = kzalloc_obj(*mtd);
49 if (!mtd)
50 return NULL;
51
52 map->fldrv = &maprom_chipdrv;
53 mtd->priv = map;
54 mtd->name = map->name;
55 mtd->type = MTD_ROM;
56 mtd->size = map->size;
57 mtd->_point = maprom_point;
58 mtd->_unpoint = maprom_unpoint;
59 mtd->_read = maprom_read;
60 mtd->_write = maprom_write;
61 mtd->_sync = maprom_nop;
62 mtd->_erase = maprom_erase;
63 mtd->flags = MTD_CAP_ROM;
64 mtd->erasesize = default_erasesize(map);
65 mtd->writesize = 1;
66 mtd->writebufsize = 1;
67
68 __module_get(THIS_MODULE);
69 return mtd;
70}
71
72
73static int maprom_point(struct mtd_info *mtd, loff_t from, size_t len,
74 size_t *retlen, void **virt, resource_size_t *phys)
75{
76 struct map_info *map = mtd->priv;
77
78 if (!map->virt)
79 return -EINVAL;
80 *virt = map->virt + from;
81 if (phys)
82 *phys = map->phys + from;
83 *retlen = len;
84 return 0;
85}
86
87static int maprom_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
88{
89 return 0;
90}
91
92static int maprom_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
93{
94 struct map_info *map = mtd->priv;
95
96 map_copy_from(map, buf, from, len);
97 *retlen = len;
98 return 0;
99}
100
101static void maprom_nop(struct mtd_info *mtd)
102{
103 /* Nothing to see here */
104}
105
106static int maprom_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)
107{
108 return -EROFS;
109}
110
111static int maprom_erase (struct mtd_info *mtd, struct erase_info *info)
112{
113 /* We do our best 8) */
114 return -EROFS;
115}
116
117static int __init map_rom_init(void)
118{
119 register_mtd_chip_driver(&maprom_chipdrv);
120 return 0;
121}
122
123static void __exit map_rom_exit(void)
124{
125 unregister_mtd_chip_driver(&maprom_chipdrv);
126}
127
128module_init(map_rom_init);
129module_exit(map_rom_exit);
130
131MODULE_LICENSE("GPL");
132MODULE_AUTHOR("David Woodhouse <[email protected]>");
133MODULE_DESCRIPTION("MTD chip driver for ROM chips");