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kernel/linux-rt-4.4.41/drivers/mtd/chips/map_rom.c 3.01 KB
5113f6f70   김현기   kernel add
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  /*
   * Common code to handle map devices which are simple ROM
   * (C) 2000 Red Hat. GPL'd.
   */
  
  #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 unsigned long maprom_unmapped_area(struct mtd_info *, unsigned long,
  					  unsigned long, unsigned long);
  
  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(sizeof(*mtd), GFP_KERNEL);
  	if (!mtd)
  		return NULL;
  
  	map->fldrv = &maprom_chipdrv;
  	mtd->priv = map;
  	mtd->name = map->name;
  	mtd->type = MTD_ROM;
  	mtd->size = map->size;
  	mtd->_get_unmapped_area = maprom_unmapped_area;
  	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;
  }
  
  
  /*
   * Allow NOMMU mmap() to directly map the device (if not NULL)
   * - return the address to which the offset maps
   * - return -ENOSYS to indicate refusal to do the mapping
   */
  static unsigned long maprom_unmapped_area(struct mtd_info *mtd,
  					  unsigned long len,
  					  unsigned long offset,
  					  unsigned long flags)
  {
  	struct map_info *map = mtd->priv;
  	return (unsigned long) map->virt + offset;
  }
  
  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");