Didj 2.6.31 Kernel

Summary

This tutorial will take you through the basic steps to get the 2.6.31 Kernel (LF-Linux-2503-20110602-1237.tar.gz) loading on your Didj. This will only deal with the kernel, and will be set up to run completely from SD, rootfs included.

Prerequisites

Kernel Configuration

Software Needed

Leapster Explorer Source (LF-Linux-2503-20110602-1237.tar.gz)

Example Config File

Example Binary zImage

lf1000.c JFFS2/Partions Enabled

mes_sdhc.c explorer/didj updated mmc driver

Hardware needed

Console Access

Driver patching and Kernel Configuration

Here we will configure the kernel for compiling, currently if you are using Lightning Boot 1.4 to 2.1 there is a problem with the bootloaders framebuffer and where the kernel is loaded. Two ways currently around this, create a kernel < 2mb or boot it manually with uboot and a lower address. This tutorial uses the < 2mb method, which is easy to achieve after all the modules for things Didj doesn't have are removed and we've set a couple of things up like tux boot image.

Unpack your sources to a suitable dir, download the mes_sdhc.c explorer/didj updated mmc driver from the link in the software needed section, copy it to linux-2.6/drivers/mmc/host overwriting the original version. This enables the sd0 port to be enabled at boot time for the didj and explorer.

Now download the lf1000.c JFFS2/Partions Enabled file from the software needed section, copy it to linux-2.6/drivers/mtd/nand/, this will allow us to see and mount the didj partitions once we've got the kernel booted.

Now download the Example Config file from the software needed section, copy it to linux-2.6/arch/arm/configs, this will give you the kernel .config that we know works with all versions of lightning boot from 1.4-2.1. If you want to see what we've done compare the lf1000_didj_defconfig you downloaded to lf1000_ts_defconfig for more details.

This will disable a few things, such as Touch Screen, Acellerometer, Camera, USB Host, 3d etc. but it will also add tux while it boots and still produces a kernel that it 1.8MB well below the limits set by lightning boot.

at the command line do:

make lf1000_didj_defconfig

this will load the defconfig into our .config file, almost ready to compile the kernel :)

Next we need to change the Mach Type in /linux-2.6/arch/arm/tools/mach-types the number has changed to 2028 - but the boot loader only knows about 1235:

#zir2412		MACH_ZIR2412		ZIR2412			1235
didj			MACH_DIDJ		DIDJ			1235
...
...

#didj			MACH_DIDJ		DIDJ			2028

Then just run the install script from linux-2.6/ directory.

./install.sh

zImage will be found in the path defined with $TFTP_PATH in your Environmental Variables

or you can just do:

make zImage

zImage will be in linux-2.6/arch/arm/boot

Of course if you don't want to do all that you can download a prebuilt kernel from the software needed section.

To Do:

Fixup the audio driver?  Might just need the right rootfs on the card :D
fixup the volume button
writeup putting a rootfs on the sd card
fixup the divide by zero error in the kernel boot messages, I think its the mtd_part_size thing in the nand driver changes, it uses a null flag to tell the driver to do from that point to the end of the remaining nand without having to work things out.