Linux-2.6.12-rc2
[linux-2.6/kvm.git] / drivers / mtd / chips / map_ram.c
blobbd2e876a814bfc6374660379b83503c64be2841e
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 */
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>
20 static int mapram_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
21 static int mapram_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
22 static int mapram_erase (struct mtd_info *, struct erase_info *);
23 static void mapram_nop (struct mtd_info *);
24 static struct mtd_info *map_ram_probe(struct map_info *map);
27 static struct mtd_chip_driver mapram_chipdrv = {
28 .probe = map_ram_probe,
29 .name = "map_ram",
30 .module = THIS_MODULE
33 static struct mtd_info *map_ram_probe(struct map_info *map)
35 struct mtd_info *mtd;
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;
43 map_write8(map, 0xAA, 0);
44 if (map_read8(map, 0) != 0xAA)
45 return NULL;
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;
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. */
58 mtd = kmalloc(sizeof(*mtd), GFP_KERNEL);
59 if (!mtd)
60 return NULL;
62 memset(mtd, 0, sizeof(*mtd));
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;
75 mtd->erasesize = PAGE_SIZE;
76 while(mtd->size & (mtd->erasesize - 1))
77 mtd->erasesize >>= 1;
79 __module_get(THIS_MODULE);
80 return mtd;
84 static int mapram_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
86 struct map_info *map = mtd->priv;
88 map_copy_from(map, buf, from, len);
89 *retlen = len;
90 return 0;
93 static int mapram_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)
95 struct map_info *map = mtd->priv;
97 map_copy_to(map, to, buf, len);
98 *retlen = len;
99 return 0;
102 static int mapram_erase (struct mtd_info *mtd, struct erase_info *instr)
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;
110 allff = map_word_ff(map);
112 for (i=0; i<instr->len; i += map_bankwidth(map))
113 map_write(map, allff, instr->addr + i);
115 instr->state = MTD_ERASE_DONE;
117 mtd_erase_callback(instr);
119 return 0;
122 static void mapram_nop(struct mtd_info *mtd)
124 /* Nothing to see here */
127 static int __init map_ram_init(void)
129 register_mtd_chip_driver(&mapram_chipdrv);
130 return 0;
133 static void __exit map_ram_exit(void)
135 unregister_mtd_chip_driver(&mapram_chipdrv);
138 module_init(map_ram_init);
139 module_exit(map_ram_exit);
141 MODULE_LICENSE("GPL");
142 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
143 MODULE_DESCRIPTION("MTD chip driver for RAM chips");