map_ram.c revision 17ffc7ba6d7ea68b8d5f55a5ca1b87163e69720d
11da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds/*
21da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * Common code to handle map devices which are simple RAM
31da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * (C) 2000 Red Hat. GPL'd.
41da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds * $Id: map_ram.c,v 1.22 2005/01/05 18:05:12 dwmw2 Exp $
51da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds */
61da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
71da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/module.h>
81da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/types.h>
91da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/kernel.h>
101da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <asm/io.h>
111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <asm/byteorder.h>
121da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/errno.h>
131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/slab.h>
141da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/init.h>
151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/mtd/mtd.h>
161da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/mtd/map.h>
171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#include <linux/mtd/compatmac.h>
181da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
201da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int mapram_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
211da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int mapram_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
221da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int mapram_erase (struct mtd_info *, struct erase_info *);
231da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic void mapram_nop (struct mtd_info *);
241da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic struct mtd_info *map_ram_probe(struct map_info *map);
251da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
261da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
271da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic struct mtd_chip_driver mapram_chipdrv = {
281da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	.probe	= map_ram_probe,
291da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	.name	= "map_ram",
301da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	.module	= THIS_MODULE
311da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds};
321da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
331da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic struct mtd_info *map_ram_probe(struct map_info *map)
341da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{
351da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	struct mtd_info *mtd;
361da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
371da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	/* Check the first byte is RAM */
381da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#if 0
391da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	map_write8(map, 0x55, 0);
401da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	if (map_read8(map, 0) != 0x55)
411da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds		return NULL;
421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	map_write8(map, 0xAA, 0);
441da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	if (map_read8(map, 0) != 0xAA)
451da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds		return NULL;
461da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
471da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	/* Check the last byte is RAM */
481da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	map_write8(map, 0x55, map->size-1);
491da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	if (map_read8(map, map->size-1) != 0x55)
501da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds		return NULL;
511da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
521da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	map_write8(map, 0xAA, map->size-1);
531da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	if (map_read8(map, map->size-1) != 0xAA)
541da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds		return NULL;
551da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds#endif
561da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	/* OK. It seems to be RAM. */
571da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
581da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	mtd = kmalloc(sizeof(*mtd), GFP_KERNEL);
591da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	if (!mtd)
601da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds		return NULL;
611da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
621da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	memset(mtd, 0, sizeof(*mtd));
631da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
641da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	map->fldrv = &mapram_chipdrv;
651da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	mtd->priv = map;
661da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	mtd->name = map->name;
6721c8db9eff95260e543535dfc6f27164c4c0c0ffDavid Woodhouse	mtd->type = MTD_RAM;
681da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	mtd->size = map->size;
691da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	mtd->erase = mapram_erase;
701da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	mtd->read = mapram_read;
711da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	mtd->write = mapram_write;
721da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	mtd->sync = mapram_nop;
73a6c591eda3078f92e7a3ff3db55f6841e4819fb5Jörn Engel	mtd->flags = MTD_CAP_RAM;
7417ffc7ba6d7ea68b8d5f55a5ca1b87163e69720dArtem B. Bityutskiy	mtd->writesize = 1;
751da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
761da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	mtd->erasesize = PAGE_SIZE;
771da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds 	while(mtd->size & (mtd->erasesize - 1))
781da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds		mtd->erasesize >>= 1;
791da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
801da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	__module_get(THIS_MODULE);
811da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	return mtd;
821da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds}
831da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
841da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
851da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int mapram_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
861da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{
871da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	struct map_info *map = mtd->priv;
881da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
891da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	map_copy_from(map, buf, from, len);
901da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	*retlen = len;
911da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	return 0;
921da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds}
931da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
941da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int mapram_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)
951da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{
961da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	struct map_info *map = mtd->priv;
971da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
981da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	map_copy_to(map, to, buf, len);
991da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	*retlen = len;
1001da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	return 0;
1011da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds}
1021da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
1031da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int mapram_erase (struct mtd_info *mtd, struct erase_info *instr)
1041da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{
1051da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	/* Yeah, it's inefficient. Who cares? It's faster than a _real_
1061da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	   flash erase. */
1071da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	struct map_info *map = mtd->priv;
1081da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	map_word allff;
1091da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	unsigned long i;
1101da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
1111da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	allff = map_word_ff(map);
1121da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
1131da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	for (i=0; i<instr->len; i += map_bankwidth(map))
1141da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds		map_write(map, allff, instr->addr + i);
1151da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
1161da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	instr->state = MTD_ERASE_DONE;
1171da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
1181da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	mtd_erase_callback(instr);
1191da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
1201da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	return 0;
1211da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds}
1221da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
1231da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic void mapram_nop(struct mtd_info *mtd)
1241da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{
1251da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	/* Nothing to see here */
1261da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds}
1271da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
1281da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic int __init map_ram_init(void)
1291da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{
1301da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	register_mtd_chip_driver(&mapram_chipdrv);
1311da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	return 0;
1321da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds}
1331da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
1341da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsstatic void __exit map_ram_exit(void)
1351da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds{
1361da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds	unregister_mtd_chip_driver(&mapram_chipdrv);
1371da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds}
1381da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
1391da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsmodule_init(map_ram_init);
1401da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvaldsmodule_exit(map_ram_exit);
1411da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus Torvalds
1421da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus TorvaldsMODULE_LICENSE("GPL");
1431da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus TorvaldsMODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
1441da177e4c3f41524e886b7f1b8a0c1fc7321cacLinus TorvaldsMODULE_DESCRIPTION("MTD chip driver for RAM chips");
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