Hi Matthias,
Thank you very much for your help. Unfortunately I'm still a little stuck.
Matthias Brugger wrote
- as you found out U-Boot is using an embedded device tree. The device
tree it uses is specified in configs/rpi_* I suppose you are using rpi_3_defconfig, so your device-tree is: bcm2837-rpi-3-b You can find the device-tree files in arch/arm/dts where you can change the files.
I had a go at this, but with little success. The Compute Module 1 is actually based off the hardware of the original 256Mb Raspberry Pi 1. I've tried using the bcm2837-rpi-3-b device-tree, but I just get (what I've come to call) the Rainbow Screen of Death and nothing boots. Using the bcm2835-rpi-b tree allows it to boot.
I tried modifying the file to include the second UART port, by adding the following lines to the end (underneath the definition for &uart0), but unfortunately it doesn't seem to work:
&uart1 { pinctrl-names = "default"; pinctrl-0 = <&uart1_gpio40>; status = "okay"; };
I'm testing this by calling `coninfo` in the uboot prompt. Two serial ports show, however only one has an address next to it and it's the address of the main serial port. It looks like the following:
List of available devices: serial@7e201000 00000007 IO serial 00000003 IO stdin nulldev 00000003 IO vidconsole 00000002 .O stdout stderr
Am I interpreting that correctly? Or is the serial port somehow enabled without an address?
'Matthias Brugger" wrote
- you can update the config to use CONFIG_OF_BOARD instead of
CONFIG_OF_EMBED. This will take the device-tree from the file specified in config.txt (or to be correct the RPi FW will pass this device-tree to U-Boot in a register at startup).
Doing this (but leaving the default device tree the same) results in no changes to the output of `coninfo`. Is there something I need to do to tell uboot where in memory the device-tree is stored?
I've also tried playing around with CONFIG_SPECIFY_CONSOLE_INDEX but that had no effect either. Is there something that needs adding to the header file to specify the serial port?
Thanks once again for your help, Ed
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