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Commit | Line | Data |
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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 | ||
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); | |
23 | static unsigned long mapram_unmapped_area(struct mtd_info *, unsigned long, | |
24 | unsigned long, unsigned long); | |
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 | ||
58 | mtd = kzalloc(sizeof(*mtd), GFP_KERNEL); | |
59 | if (!mtd) | |
60 | return NULL; | |
61 | ||
62 | map->fldrv = &mapram_chipdrv; | |
63 | mtd->priv = map; | |
64 | mtd->name = map->name; | |
65 | mtd->type = MTD_RAM; | |
66 | mtd->size = map->size; | |
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->_panic_write = mapram_write; | |
72 | mtd->_sync = mapram_nop; | |
73 | mtd->flags = MTD_CAP_RAM; | |
74 | mtd->writesize = 1; | |
75 | ||
76 | mtd->erasesize = PAGE_SIZE; | |
77 | while(mtd->size & (mtd->erasesize - 1)) | |
78 | mtd->erasesize >>= 1; | |
79 | ||
80 | __module_get(THIS_MODULE); | |
81 | return mtd; | |
82 | } | |
83 | ||
84 | ||
85 | /* | |
86 | * Allow NOMMU mmap() to directly map the device (if not NULL) | |
87 | * - return the address to which the offset maps | |
88 | * - return -ENOSYS to indicate refusal to do the mapping | |
89 | */ | |
90 | static unsigned long mapram_unmapped_area(struct mtd_info *mtd, | |
91 | unsigned long len, | |
92 | unsigned long offset, | |
93 | unsigned long flags) | |
94 | { | |
95 | struct map_info *map = mtd->priv; | |
96 | return (unsigned long) map->virt + offset; | |
97 | } | |
98 | ||
99 | static int mapram_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf) | |
100 | { | |
101 | struct map_info *map = mtd->priv; | |
102 | ||
103 | map_copy_from(map, buf, from, len); | |
104 | *retlen = len; | |
105 | return 0; | |
106 | } | |
107 | ||
108 | static int mapram_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf) | |
109 | { | |
110 | struct map_info *map = mtd->priv; | |
111 | ||
112 | map_copy_to(map, to, buf, len); | |
113 | *retlen = len; | |
114 | return 0; | |
115 | } | |
116 | ||
117 | static int mapram_erase (struct mtd_info *mtd, struct erase_info *instr) | |
118 | { | |
119 | /* Yeah, it's inefficient. Who cares? It's faster than a _real_ | |
120 | flash erase. */ | |
121 | struct map_info *map = mtd->priv; | |
122 | map_word allff; | |
123 | unsigned long i; | |
124 | ||
125 | allff = map_word_ff(map); | |
126 | for (i=0; i<instr->len; i += map_bankwidth(map)) | |
127 | map_write(map, allff, instr->addr + i); | |
128 | instr->state = MTD_ERASE_DONE; | |
129 | mtd_erase_callback(instr); | |
130 | return 0; | |
131 | } | |
132 | ||
133 | static void mapram_nop(struct mtd_info *mtd) | |
134 | { | |
135 | /* Nothing to see here */ | |
136 | } | |
137 | ||
138 | static int __init map_ram_init(void) | |
139 | { | |
140 | register_mtd_chip_driver(&mapram_chipdrv); | |
141 | return 0; | |
142 | } | |
143 | ||
144 | static void __exit map_ram_exit(void) | |
145 | { | |
146 | unregister_mtd_chip_driver(&mapram_chipdrv); | |
147 | } | |
148 | ||
149 | module_init(map_ram_init); | |
150 | module_exit(map_ram_exit); | |
151 | ||
152 | MODULE_LICENSE("GPL"); | |
153 | MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); | |
154 | MODULE_DESCRIPTION("MTD chip driver for RAM chips"); |