From: edrose <edrose@outramresearch.co.uk>
To: u-boot@lists.denx.de
Subject: [U-Boot] Raspberry Pi Compute Module 1 mini-UART
Date: Wed, 27 Nov 2019 03:56:36 -0700 (MST) [thread overview]
Message-ID: <1574852196100-0.post@n7.nabble.com> (raw)
In-Reply-To: <911e6e2b-d5fc-3250-2f92-6bf44f80edc1@gmail.com>
Hi Matthias,
Thank you very much for your help. Unfortunately I'm still a little stuck.
Matthias Brugger wrote
> 1) 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 at 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
> 2) 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
--
Sent from: http://u-boot.10912.n7.nabble.com/
next prev parent reply other threads:[~2019-11-27 10:56 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-25 20:47 [U-Boot] Raspberry Pi Compute Module 1 mini-UART edrose
2019-11-26 18:09 ` Matthias Brugger
2019-11-27 10:56 ` edrose [this message]
2019-11-29 16:34 ` edrose
2019-12-03 20:14 ` edrose
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