Xenomai - Mini Howto
Contents
Xenomai
The following quick guide gives a rough overview how I got Adeos & Xenomai (real-time extension for Linux) running on the verdex.
Quick Install Guide
Step 1: Gumstix OE setup
At first, setup the build environment.
Note, that the step
$ cat gumstix-oe/extras/profile >> ~/.bashrc
defines environment variables - amongst others, it sets the directory for USERBRANCH which is used to provide our custom bitbake package.
Step 2: Custom Configuration
Download the user.collection to build Xenomai for Gumstix OE. Unpacking the file in the Gumstix OE root directory will give the following structure:
user.collection user.collection/conf user.collection/conf/machine user.collection/conf/machine/include user.collection/packages user.collection/packages/xenomai user.collection/packages/xenomai/xenomai-2.4.6 user.collection/packages/linux user.collection/packages/linux/gumstix-xenomai-kernel-2.6.24 user.collection/packages/linux/gumstix-xenomai-kernel-2.6.24/gumstix-custom-verdex
Step 3: (Re-)build the kernel and system
$ bitbake gumstix-xenomai-kernel $ bitbake -c rebuild task-base-gumstix $ bitbake -c rebuild gumstix-basic-image
Step 4: Images
The kernel and root filesystem image can be found in tmp/deploy/glibc/images.
Troubleshooting
Clock issues (Xenomai on verdex with Qemu)
It is also possible to run the real-time kernel within Qemu. However, it might be necessary to slow down the clock of the emulated system (Probably, as your host computer is too slow).
The following steps can help:
Alter the file hw/pxa2xx_timer.c:
1. Change all occurences of qemu_get_clock(vm_clock) by PXA2XX_QEMU_GET_CLOCK()
2. Define the macro
#define PXA2XX_QEMU_GET_CLOCK() (qemu_get_clock(vm_clock) >> 4) /* also try 2,3 or use a divider */
