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 18static int mapram_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *); 19static int mapram_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *); 20static int mapram_erase (struct mtd_info *, struct erase_info *); 21static void mapram_nop (struct mtd_info *); 22static struct mtd_info *map_ram_probe(struct map_info *map); 23static unsigned long mapram_unmapped_area(struct mtd_info *, unsigned long, 24 unsigned long, unsigned long); 25 26 27static struct mtd_chip_driver mapram_chipdrv = { 28 .probe = map_ram_probe, 29 .name = "map_ram", 30 .module = THIS_MODULE 31}; 32 33static 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 /* OK. It seems to be RAM. */ 39 40 mtd = kzalloc(sizeof(*mtd), GFP_KERNEL); 41 if (!mtd) 42 return NULL; 43 44 map->fldrv = &mapram_chipdrv; 45 mtd->priv = map; 46 mtd->name = map->name; 47 mtd->type = MTD_RAM; 48 mtd->size = map->size; 49 mtd->erase = mapram_erase; 50 mtd->get_unmapped_area = mapram_unmapped_area; 51 mtd->read = mapram_read; 52 mtd->write = mapram_write; 53 mtd->sync = mapram_nop; 54 mtd->flags = MTD_CAP_RAM; 55 mtd->writesize = 1; 56 57 mtd->erasesize = PAGE_SIZE; 58 while(mtd->size & (mtd->erasesize - 1)) 59 mtd->erasesize >>= 1; 60 61 __module_get(THIS_MODULE); 62 return mtd; 63} 64 65 66/* 67 * Allow NOMMU mmap() to directly map the device (if not NULL) 68 * - return the address to which the offset maps 69 * - return -ENOSYS to indicate refusal to do the mapping 70 */ 71static unsigned long mapram_unmapped_area(struct mtd_info *mtd, 72 unsigned long len, 73 unsigned long offset, 74 unsigned long flags) 75{ 76 struct map_info *map = mtd->priv; 77 return (unsigned long) map->virt + offset; 78} 79 80static int mapram_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf) 81{ 82 struct map_info *map = mtd->priv; 83 84 map_copy_from(map, buf, from, len); 85 *retlen = len; 86 return 0; 87} 88 89static int mapram_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf) 90{ 91 struct map_info *map = mtd->priv; 92 93 map_copy_to(map, to, buf, len); 94 *retlen = len; 95 return 0; 96} 97 98static int mapram_erase (struct mtd_info *mtd, struct erase_info *instr) 99{ 100 /* Yeah, it's inefficient. Who cares? It's faster than a _real_ 101 flash erase. */ 102 struct map_info *map = mtd->priv; 103 map_word allff; 104 unsigned long i; 105 106 allff = map_word_ff(map); 107 108 for (i=0; i<instr->len; i += map_bankwidth(map)) 109 map_write(map, allff, instr->addr + i); 110 111 instr->state = MTD_ERASE_DONE; 112 113 mtd_erase_callback(instr); 114 115 return 0; 116} 117 118static void mapram_nop(struct mtd_info *mtd) 119{ 120 /* Nothing to see here */ 121} 122 123static int __init map_ram_init(void) 124{ 125 register_mtd_chip_driver(&mapram_chipdrv); 126 return 0; 127} 128 129static void __exit map_ram_exit(void) 130{ 131 unregister_mtd_chip_driver(&mapram_chipdrv); 132} 133 134module_init(map_ram_init); 135module_exit(map_ram_exit); 136 137MODULE_LICENSE("GPL"); 138MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>"); 139MODULE_DESCRIPTION("MTD chip driver for RAM chips"); 140