The changes were very minor.   Here's all I had to do.

1. cd to the EPICS base configure/os directory.

2. Edit CONFIG.Common.linux-arm, set the GNU_DIR appropriately and check that the rest looks like:
# CONFIG.Common.linux-arm
#
# This file is maintained by the build community.
#
# Definitions for linux-arm target builds.

# Sites may override these definitions in CONFIG_SITE.Common.linux-arm
#-------------------------------------------------------

# Include definitions common to all Linux targets
include $(CONFIG)/os/CONFIG.Common.linuxCommon

ARCH_CLASS = arm

#
# The vendor's tool chain needs to be located here
#
GNU_DIR=/Users/wenorum/src/SheevaPlug/SheevaPlugCD1.2b/SheevaPlug_Host_SWsupportPackageLinuxHost/LinuxHost/gcc

ifeq ($(BUILD_CLASS),CROSS)
   VALID_BUILDS = Ioc
   GNU_TARGET = xscale_be
   CMPLR_PREFIX = arm-none-linux-gnueabi-
endif


3. Add linux-arm to the CROSS_COMPILER_TARGET_ARCHS in  CONFIG_SITE.linux-x86.Common
# CONFIG_SITE.linux-x86.Common
#
# CONFIG_SITE.linux-x86.Common,v 1.7.2.6 2009/01/23 20:24:59 norume Exp
# This file is maintained by the build community.
#
# Site override definitions for linux-x86 host builds
#-------------------------------------------------------

# JBA test override values
#CROSS_COMPILER_TARGET_ARCHS = vxWorks-68040 solaris-sparc
#CROSS_COMPILER_TARGET_ARCHS = vxWorks-68040
CROSS_COMPILER_TARGET_ARCHS = linux-arm

On Mar 1, 2011, at 8:21 AM, Dr. Peter Zumbruch wrote:

> Hello Eric,
> I would be interested to see the changes you applied to linux-arm, 
> since I have purchased the guru-plug and would like to use it to connect to several USB devices.
>
> Thanks,
> Peter
>
> Am 25.03.2010 22:35, schrieb Eric Norum:
>>
>> We were looking for an inexpensive way to connect Larry Doolitte's Low-Level RF board to EPICS.  
>> The LLRF board uses USB to connect to the outside world so the IOC controlling it needs to be fairly close.  
>> We purchased a SheevaPlug (http://www.globalscaletechnologies.com/p-22-sheevaplug-dev-kit-us.aspx). 
>> for around $100 (US). 
>> The SheevaPlug is a plug computer (http://www.openplug.org/) about the size and shape of a typical AC adapter.  
>> It has a USB 2.0 interface and 10/100/1000 ethernet and comes with Linux installed on the flash memory.   
>> The development kit also contains a CD with all the cross-development tools
>>
>> I made a couple of changes to <base>/configure/os/CONFIG.Common.linux-arm on my Linux host machine and, 
>> to my considerable surprise, was able to build EPICS base R3.14.11, snc/seq and asyn with no other changes. 
>> I also built the GNU Universal Software Radio Project libraries which are needed to communicate with the LLRF card. 
>> I used apt-get on the SheevaPlug to install the nfs-common and screen packages.
>>
>> I am now running the IOC on the SheevaPlug and controlling/displaying the EPICS process variables 
>> using MEDM on my OS X machine.  With a 2.3 MB/s flow from the LLRF card and processing/displaying 
>> the twelve 1024-sample waveform records 5 times per second (242 kiB/s to the EPICS client) 
>> the CPU load on the SheevaPlug is 4 to 5%.
>>
>> So, if you're looking for a really inexpensive way to interface USB equipment to EPICS 
>> you might find this a reasonable way to go.
>>
>> --
>> Eric Norum
>> wenorum@lbl.gov
>>