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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 | /* * Common code to handle map devices which are simple RAM * (C) 2000 Red Hat. GPL'd. * $Id: map_ram.c,v 1.17 2003/05/28 12:51:49 dwmw2 Exp $ */ #include <linux/module.h> #include <linux/types.h> #include <linux/kernel.h> #include <asm/io.h> #include <asm/byteorder.h> #include <linux/errno.h> #include <linux/slab.h> #include <linux/init.h> #include <linux/mtd/mtd.h> #include <linux/mtd/map.h> #include <linux/mtd/compatmac.h> static int mapram_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *); static int mapram_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *); static int mapram_erase (struct mtd_info *, struct erase_info *); static void mapram_nop (struct mtd_info *); static struct mtd_info *map_ram_probe(struct map_info *map); static struct mtd_chip_driver mapram_chipdrv = { .probe = map_ram_probe, .name = "map_ram", .module = THIS_MODULE }; static struct mtd_info *map_ram_probe(struct map_info *map) { struct mtd_info *mtd; /* Check the first byte is RAM */ #if 0 map_write8(map, 0x55, 0); if (map_read8(map, 0) != 0x55) return NULL; map_write8(map, 0xAA, 0); if (map_read8(map, 0) != 0xAA) return NULL; /* Check the last byte is RAM */ map_write8(map, 0x55, map->size-1); if (map_read8(map, map->size-1) != 0x55) return NULL; map_write8(map, 0xAA, map->size-1); if (map_read8(map, map->size-1) != 0xAA) return NULL; #endif /* OK. It seems to be RAM. */ mtd = kmalloc(sizeof(*mtd), GFP_KERNEL); if (!mtd) return NULL; memset(mtd, 0, sizeof(*mtd)); map->fldrv = &mapram_chipdrv; mtd->priv = map; mtd->name = map->name; mtd->type = MTD_RAM; mtd->size = map->size; mtd->erase = mapram_erase; mtd->read = mapram_read; mtd->write = mapram_write; mtd->sync = mapram_nop; mtd->flags = MTD_CAP_RAM | MTD_VOLATILE; mtd->erasesize = PAGE_SIZE; while(mtd->size & (mtd->erasesize - 1)) mtd->erasesize >>= 1; __module_get(THIS_MODULE); return mtd; } static int mapram_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf) { struct map_info *map = (struct map_info *)mtd->priv; map_copy_from(map, buf, from, len); *retlen = len; return 0; } static int mapram_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf) { struct map_info *map = (struct map_info *)mtd->priv; map_copy_to(map, to, buf, len); *retlen = len; return 0; } static int mapram_erase (struct mtd_info *mtd, struct erase_info *instr) { /* Yeah, it's inefficient. Who cares? It's faster than a _real_ flash erase. */ struct map_info *map = (struct map_info *)mtd->priv; unsigned long i; for (i=0; i<instr->len; i++) map_write8(map, 0xFF, instr->addr + i); if (instr->callback) instr->callback(instr); return 0; } static void mapram_nop(struct mtd_info *mtd) { /* Nothing to see here */ } int __init map_ram_init(void) { register_mtd_chip_driver(&mapram_chipdrv); return 0; } static void __exit map_ram_exit(void) { unregister_mtd_chip_driver(&mapram_chipdrv); } module_init(map_ram_init); module_exit(map_ram_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); MODULE_DESCRIPTION("MTD chip driver for RAM chips"); |