Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Common code to handle map devices which are simple RAM | |
3 | * (C) 2000 Red Hat. GPL'd. | |
1da177e4 LT |
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> | |
1da177e4 LT |
16 | |
17 | ||
18 | static int mapram_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *); | |
19 | static int mapram_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *); | |
20 | static int mapram_erase (struct mtd_info *, struct erase_info *); | |
21 | static void mapram_nop (struct mtd_info *); | |
22 | static struct mtd_info *map_ram_probe(struct map_info *map); | |
402d3265 DH |
23 | static unsigned long mapram_unmapped_area(struct mtd_info *, unsigned long, |
24 | unsigned long, unsigned long); | |
1da177e4 LT |
25 | |
26 | ||
27 | static struct mtd_chip_driver mapram_chipdrv = { | |
28 | .probe = map_ram_probe, | |
29 | .name = "map_ram", | |
30 | .module = THIS_MODULE | |
31 | }; | |
32 | ||
33 | static 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 | ||
95b93a0c | 58 | mtd = kzalloc(sizeof(*mtd), GFP_KERNEL); |
1da177e4 LT |
59 | if (!mtd) |
60 | return NULL; | |
61 | ||
1da177e4 LT |
62 | map->fldrv = &mapram_chipdrv; |
63 | mtd->priv = map; | |
64 | mtd->name = map->name; | |
21c8db9e | 65 | mtd->type = MTD_RAM; |
1da177e4 | 66 | mtd->size = map->size; |
3c3c10bb AB |
67 | mtd->_erase = mapram_erase; |
68 | mtd->_get_unmapped_area = mapram_unmapped_area; | |
69 | mtd->_read = mapram_read; | |
70 | mtd->_write = mapram_write; | |
71 | mtd->_sync = mapram_nop; | |
a6c591ed | 72 | mtd->flags = MTD_CAP_RAM; |
17ffc7ba | 73 | mtd->writesize = 1; |
1da177e4 LT |
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 | ||
402d3265 DH |
84 | /* |
85 | * Allow NOMMU mmap() to directly map the device (if not NULL) | |
86 | * - return the address to which the offset maps | |
87 | * - return -ENOSYS to indicate refusal to do the mapping | |
88 | */ | |
89 | static unsigned long mapram_unmapped_area(struct mtd_info *mtd, | |
90 | unsigned long len, | |
91 | unsigned long offset, | |
92 | unsigned long flags) | |
93 | { | |
94 | struct map_info *map = mtd->priv; | |
95 | return (unsigned long) map->virt + offset; | |
96 | } | |
97 | ||
1da177e4 LT |
98 | static int mapram_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf) |
99 | { | |
100 | struct map_info *map = mtd->priv; | |
101 | ||
102 | map_copy_from(map, buf, from, len); | |
103 | *retlen = len; | |
104 | return 0; | |
105 | } | |
106 | ||
107 | static int mapram_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf) | |
108 | { | |
109 | struct map_info *map = mtd->priv; | |
110 | ||
111 | map_copy_to(map, to, buf, len); | |
112 | *retlen = len; | |
113 | return 0; | |
114 | } | |
115 | ||
116 | static int mapram_erase (struct mtd_info *mtd, struct erase_info *instr) | |
117 | { | |
118 | /* Yeah, it's inefficient. Who cares? It's faster than a _real_ | |
119 | flash erase. */ | |
120 | struct map_info *map = mtd->priv; | |
121 | map_word allff; | |
122 | unsigned long i; | |
123 | ||
124 | allff = map_word_ff(map); | |
1da177e4 LT |
125 | for (i=0; i<instr->len; i += map_bankwidth(map)) |
126 | map_write(map, allff, instr->addr + i); | |
1da177e4 | 127 | instr->state = MTD_ERASE_DONE; |
1da177e4 | 128 | mtd_erase_callback(instr); |
1da177e4 LT |
129 | return 0; |
130 | } | |
131 | ||
132 | static void mapram_nop(struct mtd_info *mtd) | |
133 | { | |
134 | /* Nothing to see here */ | |
135 | } | |
136 | ||
137 | static int __init map_ram_init(void) | |
138 | { | |
139 | register_mtd_chip_driver(&mapram_chipdrv); | |
140 | return 0; | |
141 | } | |
142 | ||
143 | static void __exit map_ram_exit(void) | |
144 | { | |
145 | unregister_mtd_chip_driver(&mapram_chipdrv); | |
146 | } | |
147 | ||
148 | module_init(map_ram_init); | |
149 | module_exit(map_ram_exit); | |
150 | ||
151 | MODULE_LICENSE("GPL"); | |
152 | MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); | |
153 | MODULE_DESCRIPTION("MTD chip driver for RAM chips"); |