Hi,
I'm working on a project that uses the Raspberry Pi Compute Module 1. Much like the CM 3, the CM 1 has two UART interfaces - the main UART at ttyAMA0, and a second "mini-UART" at ttyS0. The project uses the main UART since it works better at high speeds, so the console has been bumped over to the mini-UART. This works fine for kernel messages and as a TTY console for logging in and interacting with the device, however I've been unable to get u-boot to present it's console over the mini-UART.
I've worked deep enough into this to know that u-boot doesn't use the device tree that is set-up in config.txt, so the parameters that I've put in there to activate and remap the mini-UART (UART1 in dts files) to pins 40/41 doesn't apply to u-boot. I'm using the bcm2835-rpi-b dts file currently since it's the best fit for the hardware, but it leaves the mini-UART port disabled. I've tried playing around with the dts files to enable/remap the mini-UART port however I've been unsuccessful.
Can anyone give me any pointers as to how I modify the dts files to enable and map the second UART for u-boot to be able to use it?
Kindest regards, Ed
-- Sent from: http://u-boot.10912.n7.nabble.com/