[seL4] camkes-arm-vm not registering GPIO?

Kent.Mcleod at data61.csiro.au Kent.Mcleod at data61.csiro.au
Wed May 10 15:26:17 AEST 2017

Hi Steven,

Your problem could be that the GPIO MMIO frame is not being given to the VM.  The config setting CONFIG_TK1_INSECURE increases the amount of hardware devices that are 
passed through to the VM.  Once the GPIO device is accessible in the VM, Linux should be able to attach its own GPIO driver which will then make it accessible through sysfs. 

Currently on TK1 there isn't support for virtualisation of the GPIO hardware so you can either give Linux access to the hardware frames to manage GPIO hardware itself, or use a limited seL4 gpio driver in a separate CAmkES component but this wouldn't be accessible from on top of Linux unless you created your own virtual device.  
Hope this helps.

Kind regards,
From: Devel <devel-bounces at sel4.systems> on behalf of Steven Johnston <steve.johnston at adventiumlabs.com>
Sent: Tuesday, May 9, 2017 9:45 AM
To: devel at sel4.systems
Subject: [seL4] camkes-arm-vm not registering GPIO?

Hi All,

I am playing around with the capabilities of the camkes-arm-vm project
pn the Tegra TK1 and and wondering if someone else has come across this
issue.  It looks like GPIO functionality is not available in the buildroot.

I can confirm the GPIO source is present and is being built:


[CC] src/plat/tk1/gpio.o

The expected sysfs support is not present and looking and the relevant

# dmesg | grep gpio

[    0.057543] gpiochip_add: GPIOs 0..255 (tegra-gpio) failed to register
[    1.485061] input: gpio-keys as /devices/soc0/gpio-keys/input/input0

Any thoughts on what could be causing GPIO to the failing to register?


Devel mailing list
Devel at sel4.systems

More information about the Devel mailing list