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 int mapram_point (struct mtd_info *mtd, loff_t from, size_t len,
24 size_t *retlen, void **virt, resource_size_t *phys);
25 static int mapram_unpoint(struct mtd_info *mtd, loff_t from, size_t len);
26
27
28 static struct mtd_chip_driver mapram_chipdrv = {
29 .probe = map_ram_probe,
30 .name = "map_ram",
31 .module = THIS_MODULE
32 };
33
map_ram_probe(struct map_info * map)34 static struct mtd_info *map_ram_probe(struct map_info *map)
35 {
36 struct mtd_info *mtd;
37
38 /* Check the first byte is RAM */
39 #if 0
40 map_write8(map, 0x55, 0);
41 if (map_read8(map, 0) != 0x55)
42 return NULL;
43
44 map_write8(map, 0xAA, 0);
45 if (map_read8(map, 0) != 0xAA)
46 return NULL;
47
48 /* Check the last byte is RAM */
49 map_write8(map, 0x55, map->size-1);
50 if (map_read8(map, map->size-1) != 0x55)
51 return NULL;
52
53 map_write8(map, 0xAA, map->size-1);
54 if (map_read8(map, map->size-1) != 0xAA)
55 return NULL;
56 #endif
57 /* OK. It seems to be RAM. */
58
59 mtd = kzalloc(sizeof(*mtd), GFP_KERNEL);
60 if (!mtd)
61 return NULL;
62
63 map->fldrv = &mapram_chipdrv;
64 mtd->priv = map;
65 mtd->name = map->name;
66 mtd->type = MTD_RAM;
67 mtd->size = map->size;
68 mtd->_erase = mapram_erase;
69 mtd->_read = mapram_read;
70 mtd->_write = mapram_write;
71 mtd->_panic_write = mapram_write;
72 mtd->_point = mapram_point;
73 mtd->_sync = mapram_nop;
74 mtd->_unpoint = mapram_unpoint;
75 mtd->flags = MTD_CAP_RAM;
76 mtd->writesize = 1;
77
78 mtd->erasesize = PAGE_SIZE;
79 while(mtd->size & (mtd->erasesize - 1))
80 mtd->erasesize >>= 1;
81
82 __module_get(THIS_MODULE);
83 return mtd;
84 }
85
mapram_point(struct mtd_info * mtd,loff_t from,size_t len,size_t * retlen,void ** virt,resource_size_t * phys)86 static int mapram_point(struct mtd_info *mtd, loff_t from, size_t len,
87 size_t *retlen, void **virt, resource_size_t *phys)
88 {
89 struct map_info *map = mtd->priv;
90
91 if (!map->virt)
92 return -EINVAL;
93 *virt = map->virt + from;
94 if (phys)
95 *phys = map->phys + from;
96 *retlen = len;
97 return 0;
98 }
99
mapram_unpoint(struct mtd_info * mtd,loff_t from,size_t len)100 static int mapram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
101 {
102 return 0;
103 }
104
mapram_read(struct mtd_info * mtd,loff_t from,size_t len,size_t * retlen,u_char * buf)105 static int mapram_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
106 {
107 struct map_info *map = mtd->priv;
108
109 map_copy_from(map, buf, from, len);
110 *retlen = len;
111 return 0;
112 }
113
mapram_write(struct mtd_info * mtd,loff_t to,size_t len,size_t * retlen,const u_char * buf)114 static int mapram_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)
115 {
116 struct map_info *map = mtd->priv;
117
118 map_copy_to(map, to, buf, len);
119 *retlen = len;
120 return 0;
121 }
122
mapram_erase(struct mtd_info * mtd,struct erase_info * instr)123 static int mapram_erase (struct mtd_info *mtd, struct erase_info *instr)
124 {
125 /* Yeah, it's inefficient. Who cares? It's faster than a _real_
126 flash erase. */
127 struct map_info *map = mtd->priv;
128 map_word allff;
129 unsigned long i;
130
131 allff = map_word_ff(map);
132 for (i=0; i<instr->len; i += map_bankwidth(map))
133 map_write(map, allff, instr->addr + i);
134 return 0;
135 }
136
mapram_nop(struct mtd_info * mtd)137 static void mapram_nop(struct mtd_info *mtd)
138 {
139 /* Nothing to see here */
140 }
141
map_ram_init(void)142 static int __init map_ram_init(void)
143 {
144 register_mtd_chip_driver(&mapram_chipdrv);
145 return 0;
146 }
147
map_ram_exit(void)148 static void __exit map_ram_exit(void)
149 {
150 unregister_mtd_chip_driver(&mapram_chipdrv);
151 }
152
153 module_init(map_ram_init);
154 module_exit(map_ram_exit);
155
156 MODULE_LICENSE("GPL");
157 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
158 MODULE_DESCRIPTION("MTD chip driver for RAM chips");
159