WGT634U Tips & Tricks

New Kernel Howto

OpenWgt offers the choice of a 2.6.12-rc3 for the linux 2.6 series. This kernel comes from the Tuxap project and is slightly outdated by now. Here's how to get a more recent kernel up and running:

1. Get a new kernel (I'll go with 2.6.16) from kernel.org (I used linux-mips.org, but kernel.org should be fine) and unpack it.
2. Get the patches for bcm947xx support from OpenWrt's Kamikaze branch at https://dev.openwrt.org/browser/trunk/openwrt/target/linux/brcm-2.6/patches/
3. Apply the patches:
   $ cd linux-2.6.16
$ patch -p1 < /path/to/001-bcm947xx.patch
$ patch -p1 < /path/to/002-flash-map.patch
$ patch -p1 < /path/to/003-bcm4710_cache_fixes.patch
$ patch -p1 < /path/to/004-b44_bcm47xx_support.patch
4. You may use the .config file from the old kernel (it's in /proc/config.gz), but there are some tweaks to do:
   1. Machine selection -> System type: Support for BCM947xx based boards
   2. Device drivers -> Network device support: [*] Ethernet (10 or 100Mbit), [*] EISA, VLB, PCI and on board controller -> <*> Broadcom 4400 ethernet support (EXPERIMENTAL)
   3. (Do not enable Device drivers -> Input device support -> Hardware I/O ports -> Serial I/O support -> i8042 PC Keyboard controller, the kernel would hang while probing for a keyboard controller.)
   4. Device drivers -> Character devices -> Serial drivers -> <*> 8250/16550 and compatible serial support, [*] Console on 8250/16550 and compatible serial port
   5. Attention: Kernel hacking -> Default kernel command string, the 2.6.12-rc3 needed console=ttyS1,115200 while the 2.6.16 needs console=ttyS0,115200 for the serial console. Also: /etc/inittab should be changed to give a shell on tts/0.
5. Big change: OpenWgt used devfs for its device file system which has been deprecated for some time and is completely removed by now. For the time being you'll need to set up a static /dev directory on your root file system. Simply use tar to pack up a copy of your old /dev and untar it in your root. Note: your root will most likely be readonly, but the logger wants to create its /dev/log socket on startup. Thus you should create a symlink that links /dev/log to /tmp/log (for example).

Unionfs for linux-2.6.16

• UnionFS version 1.1.4 use a broken locking mechanism, so try a snapshot instead, e.g.:
• Prepare build

$ wget ftp://ftp.fsl.cs.sunysb.edu/pub/unionfs/snapshots/unionfs-20060503-0408.tar.gz
$ tar xzf unionfs-20060503-0408.tar.gz
$ cd unionfs-20060503-0408
$ ./patch-kernel.sh ~/linux-2.6.16-with-unionfs/

• Configure kernel

$ cd ~/linux-2.6.16-with-unionfs/
$ make menuconfig ARCH=mips (Select "File Systems" -> "Miscellaneous filesystems" -> "<M> Union fs support")
$ # patch Makefile as described here, if you don't want debugging stuff -> saves many (useless) code

• Build kernel (and/or modules)

$ cat build.sh
#!/bin/sh

CROSS_PATH=/home/mj/openwgt-dev/buildroot/build_mipsel/staging_dir/bin/

make \
CC=$CROSS_PATH/mipsel-linux-gcc \
LD=$CROSS_PATH/mipsel-linux-ld \
AR=$CROSS_PATH/mipsel-linux-ar \
NM=$CROSS_PATH/mipsel-linux-nm \
ARCH=mips $*
$ sh build.sh modules
$ ls -l fs/unionfs/unionfs.ko
-rw-r--r--  1 mj users 111415 2006-05-13 14:33 fs/unionfs/unionfs.ko