Blue Mug : ARM Linux kernel for EP7211 Maintained by Mike Touloumtzis

The ARM Linux kernel for EP7211 hardware has been through three different generations: Ben Williamson's original port of the 2.2.1 Psion (EP7110) kernel to the EP7211, the Blue Mug port of 2.4.0-test using the "ep7211" architecture name, and the Blue Mug port of 2.4.0, which integrates the earlier Blue Mug work by Jon McClintock and me with Russell King's work on the EP7212, as a common "cl-ps711x" architecture.

The 2.4.0-test kernels are currently the most featureful; on the EDB7211 board, they support the Ethernet card, framebuffer display, and keyboard. These kernels use a temporary ARM architecture number; before using them, make sure to read this README, which describes how to check the kernel architecture number. You can use shoehorn (see below) with the 2.4.0-test kernel patches, but you'll need to change the architecture number in the kernel after applying the patch.

The 2.4.0 release patch is very much a work in progress; it supports a serial driver and serial console, but none of the other drivers mentioned above. The device numbers for the serial driver have changed in this kernel version, so you might need to update the device nodes in your filesystem images. The patch is also kind of messy, as it contains a bunch of dead files from our previous kernel port.

Kernel resources:

• In-progress patches for the most recent 2.4.0 port. This patch is under development, but currently only supports a serial driver. It successfully boots from flash using the hermit boot loader.
• Patches, configs, and kernel Images for the 2.4.0-test port. As mentioned above, this is currently the most featureful port, but is no longer under development.
• Patches, notes, a kernel Image, and random other files related to the obsolete 2.2 kernel port. This is just here for reference; this port is known to be buggy, and the bugs will never get fixed.

Shoehorn downloader

The shoehorn downloader allows you to bootstrap a Linux kernel or a Hermit bootloader onto an EDB7211 evaluation board. It was originally written by Ben Williamson, and is now maintained by Mike Touloumtzis. You'll need it to run Linux on an EDB7211 evaluation board, but it's not a general purpose loader; it's specifically designed to use the onboard ROM from which the EP7211 boots in "boot mode".

Shoehorn should be easy to tweak for other EP7211 (or later) hardware. If you are intending to implement fancy new features, I suggest you consider adding them to hermit instead, since it's more general-purpose.

Shoehorn is licensed under the GNU GPL.

Shoehorn resources:

• An important README about shoehorn versions and kernel compatibility.
• The shoehorn download directory.

Hermit downloader/bootloader

Hermit is a full-featured downloader/boot loader combination. The host (PC) side of hermit is not target-specific; it retrieves a memory map, including flash blocking information and amount of memory available for buffering on the target side, and programs the flash accordingly. It can also download to RAM, and supports a simple tty-style serial terminal.

Hermit supports Ethernet downloads using raw (packet) sockets; this gives much faster downloads than serial. This is especially true given that I haven't been using serial, so I haven't yet added the bitrate switching code to handle 115200 bps downloads (which shoehorn can handle) nor any compression to make serial speeds more bearable.

Hermit doesn't yet handle Ethernet retransmits correctly, so it's best to use it with a dedicated NIC and either a crossover cable or dedicated hub.

In both cases, if you're being inconvenienced, make some noise and I'll look into adding the features; I have a pretty good idea how to do so, and it won't take long.

Hermit is licensed under the GNU GPL.

Hermit resources:

• The hermit download directory.

Problem Reporting and Troubleshooting

We're interested in hearing about problems with the 2.4-series kernel port, or with these tools. Before reporting a problem about being unable to boot the system, make sure to check the following:

• Does the architecture number in the kernel match the architecture number in the boot loader?
• Have you compiled in kernel support for your boot filesystem's type?
• Do the device nodes in your filesystem image correspond to the device nodes in the kernel serial driver (look in drivers/char/; the 2.4.0 kernels use serial_clps711x.c, the 2.4.0-test kernels use serial_ep7211.c)?
• Do you have a console (serial or framebuffer) compiled into the kernel?

Please send problem reports, comments, and patches to arm-porters@bluemug.com.