Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
1/*
2 * Common code to handle map devices which are simple RAM
3 * (C) 2000 Red Hat. GPL'd.
4 * $Id: map_ram.c,v 1.22 2005/01/05 18:05:12 dwmw2 Exp $
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/mtd/mtd.h>
16#include <linux/mtd/map.h>
17#include <linux/mtd/compatmac.h>
18
19
20static int mapram_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
21static int mapram_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
22static int mapram_erase (struct mtd_info *, struct erase_info *);
23static void mapram_nop (struct mtd_info *);
24static struct mtd_info *map_ram_probe(struct map_info *map);
25
26
27static struct mtd_chip_driver mapram_chipdrv = {
28 .probe = map_ram_probe,
29 .name = "map_ram",
30 .module = THIS_MODULE
31};
32
33static struct mtd_info *map_ram_probe(struct map_info *map)
34{
35 struct mtd_info *mtd;
36
37 /* Check the first byte is RAM */
38#if 0
39 map_write8(map, 0x55, 0);
40 if (map_read8(map, 0) != 0x55)
41 return NULL;
42
43 map_write8(map, 0xAA, 0);
44 if (map_read8(map, 0) != 0xAA)
45 return NULL;
46
47 /* Check the last byte is RAM */
48 map_write8(map, 0x55, map->size-1);
49 if (map_read8(map, map->size-1) != 0x55)
50 return NULL;
51
52 map_write8(map, 0xAA, map->size-1);
53 if (map_read8(map, map->size-1) != 0xAA)
54 return NULL;
55#endif
56 /* OK. It seems to be RAM. */
57
58 mtd = kmalloc(sizeof(*mtd), GFP_KERNEL);
59 if (!mtd)
60 return NULL;
61
62 memset(mtd, 0, sizeof(*mtd));
63
64 map->fldrv = &mapram_chipdrv;
65 mtd->priv = map;
66 mtd->name = map->name;
67 mtd->type = MTD_RAM;
68 mtd->size = map->size;
69 mtd->erase = mapram_erase;
70 mtd->read = mapram_read;
71 mtd->write = mapram_write;
72 mtd->sync = mapram_nop;
73 mtd->flags = MTD_CAP_RAM | MTD_VOLATILE;
74
75 mtd->erasesize = PAGE_SIZE;
76 while(mtd->size & (mtd->erasesize - 1))
77 mtd->erasesize >>= 1;
78
79 __module_get(THIS_MODULE);
80 return mtd;
81}
82
83
84static int mapram_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
85{
86 struct map_info *map = mtd->priv;
87
88 map_copy_from(map, buf, from, len);
89 *retlen = len;
90 return 0;
91}
92
93static int mapram_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)
94{
95 struct map_info *map = mtd->priv;
96
97 map_copy_to(map, to, buf, len);
98 *retlen = len;
99 return 0;
100}
101
102static int mapram_erase (struct mtd_info *mtd, struct erase_info *instr)
103{
104 /* Yeah, it's inefficient. Who cares? It's faster than a _real_
105 flash erase. */
106 struct map_info *map = mtd->priv;
107 map_word allff;
108 unsigned long i;
109
110 allff = map_word_ff(map);
111
112 for (i=0; i<instr->len; i += map_bankwidth(map))
113 map_write(map, allff, instr->addr + i);
114
115 instr->state = MTD_ERASE_DONE;
116
117 mtd_erase_callback(instr);
118
119 return 0;
120}
121
122static void mapram_nop(struct mtd_info *mtd)
123{
124 /* Nothing to see here */
125}
126
127static int __init map_ram_init(void)
128{
129 register_mtd_chip_driver(&mapram_chipdrv);
130 return 0;
131}
132
133static void __exit map_ram_exit(void)
134{
135 unregister_mtd_chip_driver(&mapram_chipdrv);
136}
137
138module_init(map_ram_init);
139module_exit(map_ram_exit);
140
141MODULE_LICENSE("GPL");
142MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
143MODULE_DESCRIPTION("MTD chip driver for RAM chips");