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/of.h>
15#include <linux/mtd/mtd.h>
16#include <linux/mtd/map.h>
17
18static int maprom_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
19static int maprom_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
20static void maprom_nop (struct mtd_info *);
21static struct mtd_info *map_rom_probe(struct map_info *map);
22static int maprom_erase (struct mtd_info *mtd, struct erase_info *info);
23static unsigned long maprom_unmapped_area(struct mtd_info *, unsigned long,
24					  unsigned long, unsigned long);
25
26static struct mtd_chip_driver maprom_chipdrv = {
27	.probe	= map_rom_probe,
28	.name	= "map_rom",
29	.module	= THIS_MODULE
30};
31
32static unsigned int default_erasesize(struct map_info *map)
33{
34	const __be32 *erase_size = NULL;
35
36	erase_size = of_get_property(map->device_node, "erase-size", NULL);
37
38	return !erase_size ? map->size : be32_to_cpu(*erase_size);
39}
40
41static struct mtd_info *map_rom_probe(struct map_info *map)
42{
43	struct mtd_info *mtd;
44
45	mtd = kzalloc(sizeof(*mtd), GFP_KERNEL);
46	if (!mtd)
47		return NULL;
48
49	map->fldrv = &maprom_chipdrv;
50	mtd->priv = map;
51	mtd->name = map->name;
52	mtd->type = MTD_ROM;
53	mtd->size = map->size;
54	mtd->_get_unmapped_area = maprom_unmapped_area;
55	mtd->_read = maprom_read;
56	mtd->_write = maprom_write;
57	mtd->_sync = maprom_nop;
58	mtd->_erase = maprom_erase;
59	mtd->flags = MTD_CAP_ROM;
60	mtd->erasesize = default_erasesize(map);
61	mtd->writesize = 1;
62	mtd->writebufsize = 1;
63
64	__module_get(THIS_MODULE);
65	return mtd;
66}
67
68
69/*
70 * Allow NOMMU mmap() to directly map the device (if not NULL)
71 * - return the address to which the offset maps
72 * - return -ENOSYS to indicate refusal to do the mapping
73 */
74static unsigned long maprom_unmapped_area(struct mtd_info *mtd,
75					  unsigned long len,
76					  unsigned long offset,
77					  unsigned long flags)
78{
79	struct map_info *map = mtd->priv;
80	return (unsigned long) map->virt + offset;
81}
82
83static int maprom_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
84{
85	struct map_info *map = mtd->priv;
86
87	map_copy_from(map, buf, from, len);
88	*retlen = len;
89	return 0;
90}
91
92static void maprom_nop(struct mtd_info *mtd)
93{
94	/* Nothing to see here */
95}
96
97static int maprom_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)
98{
99	return -EROFS;
100}
101
102static int maprom_erase (struct mtd_info *mtd, struct erase_info *info)
103{
104	/* We do our best 8) */
105	return -EROFS;
106}
107
108static int __init map_rom_init(void)
109{
110	register_mtd_chip_driver(&maprom_chipdrv);
111	return 0;
112}
113
114static void __exit map_rom_exit(void)
115{
116	unregister_mtd_chip_driver(&maprom_chipdrv);
117}
118
119module_init(map_rom_init);
120module_exit(map_rom_exit);
121
122MODULE_LICENSE("GPL");
123MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
124MODULE_DESCRIPTION("MTD chip driver for ROM chips");
125