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