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+-------------------------------------------------------------------------
+Release Notes for Linux on Intel's IXP4xx Network Processor
+
+Maintained by Deepak Saxena <dsaxena@plexity.net>
+-------------------------------------------------------------------------
+
+1. Overview
+
+Intel's IXP4xx network processor is a highly integrated SOC that
+is targeted for network applications, though it has become popular 
+in industrial control and other areas due to low cost and power
+consumption. The IXP4xx family currently consists of several processors
+that support different network offload functions such as encryption,
+routing, firewalling, etc. The IXP46x family is an updated version which
+supports faster speeds, new memory and flash configurations, and more
+integration such as an on-chip I2C controller.
+
+For more information on the various versions of the CPU, see:
+
+   http://developer.intel.com/design/network/products/npfamily/ixp4xx.htm
+
+Intel also made the IXCP1100 CPU for sometime which is an IXP4xx 
+stripped of much of the network intelligence.
+
+2. Linux Support
+
+Linux currently supports the following features on the IXP4xx chips:
+
+- Dual serial ports
+- PCI interface
+- Flash access (MTD/JFFS)
+- I2C through GPIO on IXP42x
+- GPIO for input/output/interrupts 
+  See arch/arm/mach-ixp4xx/include/mach/platform.h for access functions.
+- Timers (watchdog, OS)
+
+The following components of the chips are not supported by Linux and
+require the use of Intel's proprietary CSR software:
+
+- USB device interface
+- Network interfaces (HSS, Utopia, NPEs, etc)
+- Network offload functionality
+
+If you need to use any of the above, you need to download Intel's
+software from:
+
+   http://developer.intel.com/design/network/products/npfamily/ixp425.htm    
+
+DO NOT POST QUESTIONS TO THE LINUX MAILING LISTS REGARDING THE PROPRIETARY
+SOFTWARE.
+
+There are several websites that provide directions/pointers on using
+Intel's software:
+
+   http://sourceforge.net/projects/ixp4xx-osdg/
+   Open Source Developer's Guide for using uClinux and the Intel libraries 
+
+http://gatewaymaker.sourceforge.net/ 
+   Simple one page summary of building a gateway using an IXP425 and Linux
+
+http://ixp425.sourceforge.net/
+   ATM device driver for IXP425 that relies on Intel's libraries
+
+3. Known Issues/Limitations
+
+3a. Limited inbound PCI window
+
+The IXP4xx family allows for up to 256MB of memory but the PCI interface
+can only expose 64MB of that memory to the PCI bus. This means that if
+you are running with > 64MB, all PCI buffers outside of the accessible
+range will be bounced using the routines in arch/arm/common/dmabounce.c.
+   
+3b. Limited outbound PCI window
+
+IXP4xx provides two methods of accessing PCI memory space:
+
+1) A direct mapped window from 0x48000000 to 0x4bffffff (64MB).
+   To access PCI via this space, we simply ioremap() the BAR
+   into the kernel and we can use the standard read[bwl]/write[bwl]
+   macros. This is the preffered method due to speed but it
+   limits the system to just 64MB of PCI memory. This can be 
+   problamatic if using video cards and other memory-heavy devices.
+          
+2) If > 64MB of memory space is required, the IXP4xx can be 
+   configured to use indirect registers to access PCI This allows 
+   for up to 128MB (0x48000000 to 0x4fffffff) of memory on the bus. 
+   The disadvantage of this is that every PCI access requires 
+   three local register accesses plus a spinlock, but in some 
+   cases the performance hit is acceptable. In addition, you cannot 
+   mmap() PCI devices in this case due to the indirect nature
+   of the PCI window.
+
+By default, the direct method is used for performance reasons. If
+you need more PCI memory, enable the IXP4XX_INDIRECT_PCI config option.
+
+3c. GPIO as Interrupts
+
+Currently the code only handles level-sensitive GPIO interrupts 
+
+4. Supported platforms
+
+ADI Engineering Coyote Gateway Reference Platform
+http://www.adiengineering.com/productsCoyote.html
+
+   The ADI Coyote platform is reference design for those building 
+   small residential/office gateways. One NPE is connected to a 10/100
+   interface, one to 4-port 10/100 switch, and the third to and ADSL
+   interface. In addition, it also supports to POTs interfaces connected
+   via SLICs. Note that those are not supported by Linux ATM. Finally,
+   the platform has two mini-PCI slots used for 802.11[bga] cards.
+   Finally, there is an IDE port hanging off the expansion bus.
+
+Gateworks Avila Network Platform
+http://www.gateworks.com/support/overview.php
+
+   The Avila platform is basically and IXDP425 with the 4 PCI slots
+   replaced with mini-PCI slots and a CF IDE interface hanging off
+   the expansion bus.
+
+Intel IXDP425 Development Platform
+http://www.intel.com/design/network/products/npfamily/ixdpg425.htm  
+
+   This is Intel's standard reference platform for the IXDP425 and is 
+   also known as the Richfield board. It contains 4 PCI slots, 16MB
+   of flash, two 10/100 ports and one ADSL port.
+
+Intel IXDP465 Development Platform
+http://www.intel.com/design/network/products/npfamily/ixdp465.htm
+
+   This is basically an IXDP425 with an IXP465 and 32M of flash instead
+   of just 16.
+
+Intel IXDPG425 Development Platform
+
+   This is basically and ADI Coyote board with a NEC EHCI controller
+   added. One issue with this board is that the mini-PCI slots only
+   have the 3.3v line connected, so you can't use a PCI to mini-PCI
+   adapter with an E100 card. So to NFS root you need to use either
+   the CSR or a WiFi card and a ramdisk that BOOTPs and then does
+   a pivot_root to NFS.
+
+Motorola PrPMC1100 Processor Mezanine Card
+http://www.fountainsys.com
+
+   The PrPMC1100 is based on the IXCP1100 and is meant to plug into
+   and IXP2400/2800 system to act as the system controller. It simply
+   contains a CPU and 16MB of flash on the board and needs to be
+   plugged into a carrier board to function. Currently Linux only
+   supports the Motorola PrPMC carrier board for this platform.
+
+5. TODO LIST
+
+- Add support for Coyote IDE
+- Add support for edge-based GPIO interrupts
+- Add support for CF IDE on expansion bus
+
+6. Thanks
+
+The IXP4xx work has been funded by Intel Corp. and MontaVista Software, Inc.
+
+The following people have contributed patches/comments/etc:
+
+Lennerty Buytenhek
+Lutz Jaenicke
+Justin Mayfield
+Robert E. Ranslam
+[I know I've forgotten others, please email me to be added] 
+
+-------------------------------------------------------------------------
+
+Last Update: 01/04/2005