1/*
2 * Common code to handle map devices which are simple ROM
3 * (C) 2000 Red Hat. GPL'd.
4 */
5
6#include <linux/module.h>
7#include <linux/types.h>
8#include <linux/kernel.h>
9#include <asm/io.h>
10#include <asm/byteorder.h>
11#include <linux/errno.h>
12#include <linux/slab.h>
13#include <linux/init.h>
14#include <linux/mtd/mtd.h>
15#include <linux/mtd/map.h>
16
17static int maprom_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
18static int maprom_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
19static void maprom_nop (struct mtd_info *);
20static struct mtd_info *map_rom_probe(struct map_info *map);
21static int maprom_erase (struct mtd_info *mtd, struct erase_info *info);
22static unsigned long maprom_unmapped_area(struct mtd_info *, unsigned long,
23					  unsigned long, unsigned long);
24
25static struct mtd_chip_driver maprom_chipdrv = {
26	.probe	= map_rom_probe,
27	.name	= "map_rom",
28	.module	= THIS_MODULE
29};
30
31static struct mtd_info *map_rom_probe(struct map_info *map)
32{
33	struct mtd_info *mtd;
34
35	mtd = kzalloc(sizeof(*mtd), GFP_KERNEL);
36	if (!mtd)
37		return NULL;
38
39	map->fldrv = &maprom_chipdrv;
40	mtd->priv = map;
41	mtd->name = map->name;
42	mtd->type = MTD_ROM;
43	mtd->size = map->size;
44	mtd->_get_unmapped_area = maprom_unmapped_area;
45	mtd->_read = maprom_read;
46	mtd->_write = maprom_write;
47	mtd->_sync = maprom_nop;
48	mtd->_erase = maprom_erase;
49	mtd->flags = MTD_CAP_ROM;
50	mtd->erasesize = map->size;
51	mtd->writesize = 1;
52
53	__module_get(THIS_MODULE);
54	return mtd;
55}
56
57
58/*
59 * Allow NOMMU mmap() to directly map the device (if not NULL)
60 * - return the address to which the offset maps
61 * - return -ENOSYS to indicate refusal to do the mapping
62 */
63static unsigned long maprom_unmapped_area(struct mtd_info *mtd,
64					  unsigned long len,
65					  unsigned long offset,
66					  unsigned long flags)
67{
68	struct map_info *map = mtd->priv;
69	return (unsigned long) map->virt + offset;
70}
71
72static int maprom_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
73{
74	struct map_info *map = mtd->priv;
75
76	map_copy_from(map, buf, from, len);
77	*retlen = len;
78	return 0;
79}
80
81static void maprom_nop(struct mtd_info *mtd)
82{
83	/* Nothing to see here */
84}
85
86static int maprom_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)
87{
88	return -EROFS;
89}
90
91static int maprom_erase (struct mtd_info *mtd, struct erase_info *info)
92{
93	/* We do our best 8) */
94	return -EROFS;
95}
96
97static int __init map_rom_init(void)
98{
99	register_mtd_chip_driver(&maprom_chipdrv);
100	return 0;
101}
102
103static void __exit map_rom_exit(void)
104{
105	unregister_mtd_chip_driver(&maprom_chipdrv);
106}
107
108module_init(map_rom_init);
109module_exit(map_rom_exit);
110
111MODULE_LICENSE("GPL");
112MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
113MODULE_DESCRIPTION("MTD chip driver for ROM chips");
114