manipulating

U-Boot: manipulating NAND devices

U-Boot provides a set of commands to manipulate NAND devices, grouped under the nand command

• nand info Show available NAND devices and characteristics
• nand device [dev] Select or display the active NAND device
• nand read[.option] Read data from NAND
• nand write[.option] Write data on NAND
  • Use nand write.trimffs to avoid writing empty pages (those filled with 0xff)
• nand erase Erase a NAND region
• nand erase.part Erase a NAND partition
• More commands for debugging purposes

U-Boot: manipulating NOR devices

• U-Boot provides a set of commands to manipulate NOR devices

• Memory mapped NOR devices

  • flinfo [devid] Display information of all NOR devices or a specific one if devid is provided
  • cp.[bwl] Read/write data from/to the NOR device
  • erase or erase + Erase a memory region
  • erase bank Erase a memory bank
  • erase all Erase all banks
  • protect on|off Protect a memory range

• SPI NOR devices

• Grouped under the sf command
• sf probe [[bus:]cs] [hz] [mode] Probe a NOR device on
• sf read|write Read/write data from/to a SPI NOR
• sf erase + Erase a memory region
• sf update Erase + write operation

Linux: MTD devices interface with user space

• MTD devices are visible in /proc/mtd
• The user space only see MTD partitions, not the flash device under those partitions
• The mtdchar driver creates a character device for each MTD device/partition of the system
  • Usually named /dev/mtdX or /dev/mtdXro
  • Provide ioctl() to erase and manage the flash
  • Used by the mtd-utils utilities

Linux: user space flash management tools

• mtd-utils is a set of utilities to manipulate MTD devices
  • mtdinfo to get detailed information about an MTD device
  • flash_erase to partially or completely erase a given MTD device
  • flashcp to write to NOR flash
  • nandwrite to write to NAND flash
  • Flash filesystem image creation tools: mkfs.jffs2, mkfs.ubifs, ubinize, etc.
• On your workstation: usually available as the mtd-utils package in your distribution.
• On your embedded target: most commands now also available in BusyBox.
• See http://www.linux-mtd.infradead.org/.