3.1.1.8. NOR¶
This section documents how to write files to the NOR device and use it to load and then boot the Linux Kernel using a root filesystem also found on NOR. In order for NOR to be visible to U-Boot a special build of U-Boot is required on the supported hardware. The table below lists builds that see NOR and in some cases also use theit for the environment instead of the default, which typically is NAND. Finally, for simplicity we assume the files are being loaded from an SD card. Using the network interface (if applicable) is documented above.
3.1.1.8.1. Writing to NOR from U-Boot¶
Note:
- From the U-Boot build, the u-boot.bin file is the one to be written.
- We load all files from an SD card in this example but they can just as easily be loaded via network (documented above) or other interface that exists.
- At this time the NOR mtd partition map has not yet been updated to include an example location for the device tree.
| Board | Config target |
|---|---|
| AM335x EVM | am335x_evm_nor_config / am335x_evm_norboot_config |
U-Boot # mmc rescan
U-Boot # load mmc 0 ${loadaddr} u-boot.bin
U-Boot # protect off 08000000 +4c0000
U-Boot # erase 08000000 +4c0000
U-Boot # cp.b ${loadaddr} 08000000 ${filesize}
U-Boot # fatload mmc 0 ${loadaddr} zImage
U-Boot # cp.b ${loadaddr} 080c0000 ${filesize}
3.1.1.8.2. Booting from NOR¶
Within the default environment there is not a shortcut for booting. One needs to pass root=/dev/mtdblockN where N is the number of the rootfs partition in bootargs.