pico-imx6ul: Add fastboot support
fastboot tool is a convenient way to flash the eMMC, so
add support for it.
Examples of usages:
On the pico-imx6ul U-Boot prompt:
=> fastboot 0
On the Linux PC connected via USB:
1. Retrieving the U-Boot version
$ sudo fastboot getvar bootloader-version -i 0x0525
bootloader-version: U-Boot
2018.07-rc2-00130-g0881835-dirty
finished. total time: 0.000s
2. Resetting the board
$ sudo fastboot reboot -i 0x0525
(this causes the pico-imx6ul to reboot)
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Fabio Berton <fabio.berton@ossystems.com.br>
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
