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