// SPDX-License-Identifier: GPL-2.0/* * Common code to handle map devices which are simple ROM * (C) 2000 Red Hat. */ #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/of.h>#include <linux/mtd/mtd.h>#include <linux/mtd/map.h> static int maprom_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);static int maprom_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *);static void maprom_nop (struct mtd_info *);static struct mtd_info *map_rom_probe(struct map_info *map);static int maprom_erase (struct mtd_info *mtd, struct erase_info *info);static int maprom_point (struct mtd_info *mtd, loff_t from, size_t len,			 size_t *retlen, void **virt, resource_size_t *phys);static int maprom_unpoint(struct mtd_info *mtd, loff_t from, size_t len);  static struct mtd_chip_driver maprom_chipdrv = {	.probe	= map_rom_probe,	.name	= "map_rom",	.module	= THIS_MODULE}; static unsigned int default_erasesize(struct map_info *map){	const __be32 *erase_size = NULL; 	erase_size = of_get_property(map->device_node, "erase-size", NULL); 	return !erase_size ? map->size : be32_to_cpu(*erase_size);} static struct mtd_info *map_rom_probe(struct map_info *map){	struct mtd_info *mtd; 	mtd = kzalloc_obj(*mtd);	if (!mtd)		return NULL; 	map->fldrv = &maprom_chipdrv;	mtd->priv = map;	mtd->name = map->name;	mtd->type = MTD_ROM;	mtd->size = map->size;	mtd->_point = maprom_point;	mtd->_unpoint = maprom_unpoint;	mtd->_read = maprom_read;	mtd->_write = maprom_write;	mtd->_sync = maprom_nop;	mtd->_erase = maprom_erase;	mtd->flags = MTD_CAP_ROM;	mtd->erasesize = default_erasesize(map);	mtd->writesize = 1;	mtd->writebufsize = 1; 	__module_get(THIS_MODULE);	return mtd;}  static int maprom_point(struct mtd_info *mtd, loff_t from, size_t len,			size_t *retlen, void **virt, resource_size_t *phys){	struct map_info *map = mtd->priv; 	if (!map->virt)		return -EINVAL;	*virt = map->virt + from;	if (phys)		*phys = map->phys + from;	*retlen = len;	return 0;} static int maprom_unpoint(struct mtd_info *mtd, loff_t from, size_t len){	return 0;} static int maprom_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf){	struct map_info *map = mtd->priv; 	map_copy_from(map, buf, from, len);	*retlen = len;	return 0;} static void maprom_nop(struct mtd_info *mtd){	/* Nothing to see here */} static int maprom_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf){	return -EROFS;} static int maprom_erase (struct mtd_info *mtd, struct erase_info *info){	/* We do our best 8) */	return -EROFS;} static int __init map_rom_init(void){	register_mtd_chip_driver(&maprom_chipdrv);	return 0;} static void __exit map_rom_exit(void){	unregister_mtd_chip_driver(&maprom_chipdrv);} module_init(map_rom_init);module_exit(map_rom_exit); MODULE_LICENSE("GPL");MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");MODULE_DESCRIPTION("MTD chip driver for ROM chips");