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1// SPDX-License-Identifier: GPL-2.02/*3 * Common code to handle map devices which are simple ROM4 * (C) 2000 Red Hat.5 */6 7#include <linux/module.h>8#include <linux/types.h>9#include <linux/kernel.h>10#include <asm/io.h>11#include <asm/byteorder.h>12#include <linux/errno.h>13#include <linux/slab.h>14#include <linux/init.h>15#include <linux/of.h>16#include <linux/mtd/mtd.h>17#include <linux/mtd/map.h>18 19static int maprom_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);20static int maprom_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *);21static void maprom_nop (struct mtd_info *);22static struct mtd_info *map_rom_probe(struct map_info *map);23static int maprom_erase (struct mtd_info *mtd, struct erase_info *info);24static int maprom_point (struct mtd_info *mtd, loff_t from, size_t len,25 size_t *retlen, void **virt, resource_size_t *phys);26static int maprom_unpoint(struct mtd_info *mtd, loff_t from, size_t len);27 28 29static struct mtd_chip_driver maprom_chipdrv = {30 .probe = map_rom_probe,31 .name = "map_rom",32 .module = THIS_MODULE33};34 35static unsigned int default_erasesize(struct map_info *map)36{37 const __be32 *erase_size = NULL;38 39 erase_size = of_get_property(map->device_node, "erase-size", NULL);40 41 return !erase_size ? map->size : be32_to_cpu(*erase_size);42}43 44static struct mtd_info *map_rom_probe(struct map_info *map)45{46 struct mtd_info *mtd;47 48 mtd = kzalloc(sizeof(*mtd), GFP_KERNEL);49 if (!mtd)50 return NULL;51 52 map->fldrv = &maprom_chipdrv;53 mtd->priv = map;54 mtd->name = map->name;55 mtd->type = MTD_ROM;56 mtd->size = map->size;57 mtd->_point = maprom_point;58 mtd->_unpoint = maprom_unpoint;59 mtd->_read = maprom_read;60 mtd->_write = maprom_write;61 mtd->_sync = maprom_nop;62 mtd->_erase = maprom_erase;63 mtd->flags = MTD_CAP_ROM;64 mtd->erasesize = default_erasesize(map);65 mtd->writesize = 1;66 mtd->writebufsize = 1;67 68 __module_get(THIS_MODULE);69 return mtd;70}71 72 73static int maprom_point(struct mtd_info *mtd, loff_t from, size_t len,74 size_t *retlen, void **virt, resource_size_t *phys)75{76 struct map_info *map = mtd->priv;77 78 if (!map->virt)79 return -EINVAL;80 *virt = map->virt + from;81 if (phys)82 *phys = map->phys + from;83 *retlen = len;84 return 0;85}86 87static int maprom_unpoint(struct mtd_info *mtd, loff_t from, size_t len)88{89 return 0;90}91 92static int maprom_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)93{94 struct map_info *map = mtd->priv;95 96 map_copy_from(map, buf, from, len);97 *retlen = len;98 return 0;99}100 101static void maprom_nop(struct mtd_info *mtd)102{103 /* Nothing to see here */104}105 106static int maprom_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)107{108 return -EROFS;109}110 111static int maprom_erase (struct mtd_info *mtd, struct erase_info *info)112{113 /* We do our best 8) */114 return -EROFS;115}116 117static int __init map_rom_init(void)118{119 register_mtd_chip_driver(&maprom_chipdrv);120 return 0;121}122 123static void __exit map_rom_exit(void)124{125 unregister_mtd_chip_driver(&maprom_chipdrv);126}127 128module_init(map_rom_init);129module_exit(map_rom_exit);130 131MODULE_LICENSE("GPL");132MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");133MODULE_DESCRIPTION("MTD chip driver for ROM chips");134