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6958024ad5
UBI needs to know the physical erase block size, even on read-only
devices, since it defines the on-device layout. Use a device-tree
provided value to support previously written UBI on read-only NOR.
UBI also needs a non-zero writebufsize, so we set it to one.
Note: This was implemented because hardware write-protected CFI
NOR cannot be probed for the physical erase block size.
Signed-off-by: Joe Schultz <jschultz@xes-inc.ccom>
Signed-off-by: Aaron Sierra <asierra@xes-inc.ccom>
[Brian: removed unneeded #ifdef, note 'optional' erase-size property]
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
125 lines
3.0 KiB
C
125 lines
3.0 KiB
C
/*
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* Common code to handle map devices which are simple ROM
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* (C) 2000 Red Hat. GPL'd.
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <asm/io.h>
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#include <asm/byteorder.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/of.h>
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#include <linux/mtd/mtd.h>
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#include <linux/mtd/map.h>
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static int maprom_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
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static int maprom_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
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static void maprom_nop (struct mtd_info *);
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static struct mtd_info *map_rom_probe(struct map_info *map);
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static int maprom_erase (struct mtd_info *mtd, struct erase_info *info);
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static unsigned long maprom_unmapped_area(struct mtd_info *, unsigned long,
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unsigned long, unsigned long);
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static struct mtd_chip_driver maprom_chipdrv = {
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.probe = map_rom_probe,
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.name = "map_rom",
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.module = THIS_MODULE
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};
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static unsigned int default_erasesize(struct map_info *map)
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{
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const __be32 *erase_size = NULL;
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erase_size = of_get_property(map->device_node, "erase-size", NULL);
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return !erase_size ? map->size : be32_to_cpu(*erase_size);
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}
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static struct mtd_info *map_rom_probe(struct map_info *map)
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{
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struct mtd_info *mtd;
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mtd = kzalloc(sizeof(*mtd), GFP_KERNEL);
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if (!mtd)
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return NULL;
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map->fldrv = &maprom_chipdrv;
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mtd->priv = map;
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mtd->name = map->name;
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mtd->type = MTD_ROM;
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mtd->size = map->size;
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mtd->_get_unmapped_area = maprom_unmapped_area;
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mtd->_read = maprom_read;
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mtd->_write = maprom_write;
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mtd->_sync = maprom_nop;
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mtd->_erase = maprom_erase;
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mtd->flags = MTD_CAP_ROM;
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mtd->erasesize = default_erasesize(map);
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mtd->writesize = 1;
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mtd->writebufsize = 1;
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__module_get(THIS_MODULE);
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return mtd;
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}
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/*
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* Allow NOMMU mmap() to directly map the device (if not NULL)
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* - return the address to which the offset maps
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* - return -ENOSYS to indicate refusal to do the mapping
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*/
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static unsigned long maprom_unmapped_area(struct mtd_info *mtd,
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unsigned long len,
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unsigned long offset,
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unsigned long flags)
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{
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struct map_info *map = mtd->priv;
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return (unsigned long) map->virt + offset;
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}
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static int maprom_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
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{
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struct map_info *map = mtd->priv;
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map_copy_from(map, buf, from, len);
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*retlen = len;
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return 0;
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}
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static void maprom_nop(struct mtd_info *mtd)
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{
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/* Nothing to see here */
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}
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static int maprom_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)
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{
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return -EROFS;
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}
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static int maprom_erase (struct mtd_info *mtd, struct erase_info *info)
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{
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/* We do our best 8) */
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return -EROFS;
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}
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static int __init map_rom_init(void)
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{
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register_mtd_chip_driver(&maprom_chipdrv);
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return 0;
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}
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static void __exit map_rom_exit(void)
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{
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unregister_mtd_chip_driver(&maprom_chipdrv);
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}
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module_init(map_rom_init);
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module_exit(map_rom_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
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MODULE_DESCRIPTION("MTD chip driver for ROM chips");
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