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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 include/asm-arm/arch-ixp4xx/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 propietary CSR softare:
+- 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/ixp425swr1.htm
+There are several websites that provide directions/pointers on using
+Intel's software:
+ Open Source Developer's Guide for using uClinux and the Intel libraries
+ Simple one page summary of building a gateway using an IXP425 and Linux
+ 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 disadvantadge 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
+ 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
+ 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
+ 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
+ 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
+ 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.
+ See https://mcg.motorola.com/us/ds/pdf/ds0144.pdf for info
+ on the carrier board.
+- 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