Common MTD commands : Boot EEPROM/ NAND flash access from Linux

Common MTD Commands use wisely

•  cat /proc/mtd

dev:    size   erasesize  name

mtd0: 000c0000 00001000 "U-Boot"

mtd1: 00002000 00001000 "U-Boot Env"

mtd2: 00001000 00001000 "JFFS2"

mtd3: 0013d000 00001000 "my-data"

mtd4: 0013e000 00001000 "U-image/Kernel"
mtd5: 0013f000 00001000 "rootfs"
mtd6: 00140000 00001000 "mylog"
mtd7: 00141000 00001000 "mydata"

•  mtdinfo -a
• ls -l /dev/mtd*
•  flash_unlock could be used to unlock the appropriate sectors.
• flash_eraseall /dev/mtdchar0 
•  cat /dev/mtdchar0 < new.bin  ( Erase and load new file)
• cat /dev/mtdchar0 > /tmp/flash.bin ( Entire flash to file) 
• flashcp to write to NOR flash
• flash_eraseall -j /dev/mtd2

  mount -t jffs2 /dev/mtdblock2 /mnt/flash
• flash_eraseall /dev/mtd0 ( erases everything, use rarely)

IOCTL Commands

• MEMGETINFO Get layout and capabilities struct mtd_info_user *
• MEMGETREGIONINFO struct region_info_user *
• MEMWRITEOOB NAND only: write out-of-band info (ECC) struct mtd_oob_buf *
• MEMERASE Erase flash blocks struct erase_info_user *
• MEMLOCK Lock flash blocks to disallow changes struct erase_info_user *
• MEMUNLOCK Unlock flash to allow changes struct erase_info_user *
• MEMGETREGIONCOUNT Return number of erase block regions int *
• MEMREADOOB NAND only: read out-of-band info (ECC) struct mtd_oob_buf *
• MEMSETOOBSEL NAND only: set default OOB info struct nand_oobinfo*
•  The exact flash layout may be determined using the MEMGETREGIONCOUNT and MEMGETREGIONINFO commands.
• MEMERASE command may be issued to erase the desired blocks.
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