diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/arm |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'Documentation/arm')
50 files changed, 3282 insertions, 0 deletions
diff --git a/Documentation/arm/00-INDEX b/Documentation/arm/00-INDEX new file mode 100644 index 00000000000..d753fe59a24 --- /dev/null +++ b/Documentation/arm/00-INDEX @@ -0,0 +1,20 @@ +00-INDEX + - this file +Booting + - requirements for booting +Interrupts + - ARM Interrupt subsystem documentation +Netwinder + - Netwinder specific documentation +README + - General ARM documentation +SA1100 + - SA1100 documentation +XScale + - XScale documentation +empeg + - Empeg documentation +mem_alignment + - alignment abort handler documentation +nwfpe + - NWFPE floating point emulator documentation diff --git a/Documentation/arm/Booting b/Documentation/arm/Booting new file mode 100644 index 00000000000..fad566bb02f --- /dev/null +++ b/Documentation/arm/Booting @@ -0,0 +1,141 @@ + Booting ARM Linux + ================= + +Author: Russell King +Date : 18 May 2002 + +The following documentation is relevant to 2.4.18-rmk6 and beyond. + +In order to boot ARM Linux, you require a boot loader, which is a small +program that runs before the main kernel. The boot loader is expected +to initialise various devices, and eventually call the Linux kernel, +passing information to the kernel. + +Essentially, the boot loader should provide (as a minimum) the +following: + +1. Setup and initialise the RAM. +2. Initialise one serial port. +3. Detect the machine type. +4. Setup the kernel tagged list. +5. Call the kernel image. + + +1. Setup and initialise RAM +--------------------------- + +Existing boot loaders: MANDATORY +New boot loaders: MANDATORY + +The boot loader is expected to find and initialise all RAM that the +kernel will use for volatile data storage in the system. It performs +this in a machine dependent manner. (It may use internal algorithms +to automatically locate and size all RAM, or it may use knowledge of +the RAM in the machine, or any other method the boot loader designer +sees fit.) + + +2. Initialise one serial port +----------------------------- + +Existing boot loaders: OPTIONAL, RECOMMENDED +New boot loaders: OPTIONAL, RECOMMENDED + +The boot loader should initialise and enable one serial port on the +target. This allows the kernel serial driver to automatically detect +which serial port it should use for the kernel console (generally +used for debugging purposes, or communication with the target.) + +As an alternative, the boot loader can pass the relevant 'console=' +option to the kernel via the tagged lists specifying the port, and +serial format options as described in + + Documentation/kernel-parameters.txt. + + +3. Detect the machine type +-------------------------- + +Existing boot loaders: OPTIONAL +New boot loaders: MANDATORY + +The boot loader should detect the machine type its running on by some +method. Whether this is a hard coded value or some algorithm that +looks at the connected hardware is beyond the scope of this document. +The boot loader must ultimately be able to provide a MACH_TYPE_xxx +value to the kernel. (see linux/arch/arm/tools/mach-types). + + +4. Setup the kernel tagged list +------------------------------- + +Existing boot loaders: OPTIONAL, HIGHLY RECOMMENDED +New boot loaders: MANDATORY + +The boot loader must create and initialise the kernel tagged list. +A valid tagged list starts with ATAG_CORE and ends with ATAG_NONE. +The ATAG_CORE tag may or may not be empty. An empty ATAG_CORE tag +has the size field set to '2' (0x00000002). The ATAG_NONE must set +the size field to zero. + +Any number of tags can be placed in the list. It is undefined +whether a repeated tag appends to the information carried by the +previous tag, or whether it replaces the information in its +entirety; some tags behave as the former, others the latter. + +The boot loader must pass at a minimum the size and location of +the system memory, and root filesystem location. Therefore, the +minimum tagged list should look: + + +-----------+ +base -> | ATAG_CORE | | + +-----------+ | + | ATAG_MEM | | increasing address + +-----------+ | + | ATAG_NONE | | + +-----------+ v + +The tagged list should be stored in system RAM. + +The tagged list must be placed in a region of memory where neither +the kernel decompressor nor initrd 'bootp' program will overwrite +it. The recommended placement is in the first 16KiB of RAM. + +5. Calling the kernel image +--------------------------- + +Existing boot loaders: MANDATORY +New boot loaders: MANDATORY + +There are two options for calling the kernel zImage. If the zImage +is stored in flash, and is linked correctly to be run from flash, +then it is legal for the boot loader to call the zImage in flash +directly. + +The zImage may also be placed in system RAM (at any location) and +called there. Note that the kernel uses 16K of RAM below the image +to store page tables. The recommended placement is 32KiB into RAM. + +In either case, the following conditions must be met: + +- Quiesce all DMA capable devicess so that memory does not get + corrupted by bogus network packets or disk data. This will save + you many hours of debug. + +- CPU register settings + r0 = 0, + r1 = machine type number discovered in (3) above. + r2 = physical address of tagged list in system RAM. + +- CPU mode + All forms of interrupts must be disabled (IRQs and FIQs) + The CPU must be in SVC mode. (A special exception exists for Angel) + +- Caches, MMUs + The MMU must be off. + Instruction cache may be on or off. + Data cache must be off. + +- The boot loader is expected to call the kernel image by jumping + directly to the first instruction of the kernel image. + diff --git a/Documentation/arm/IXP2000 b/Documentation/arm/IXP2000 new file mode 100644 index 00000000000..e0148b6b2c4 --- /dev/null +++ b/Documentation/arm/IXP2000 @@ -0,0 +1,69 @@ + +------------------------------------------------------------------------- +Release Notes for Linux on Intel's IXP2000 Network Processor + +Maintained by Deepak Saxena <dsaxena@plexity.net> +------------------------------------------------------------------------- + +1. Overview + +Intel's IXP2000 family of NPUs (IXP2400, IXP2800, IXP2850) is designed +for high-performance network applications such high-availability +telecom systems. In addition to an XScale core, it contains up to 8 +"MicroEngines" that run special code, several high-end networking +interfaces (UTOPIA, SPI, etc), a PCI host bridge, one serial port, +flash interface, and some other odds and ends. For more information, see: + +http://developer.intel.com/design/network/products/npfamily/ixp2xxx.htm + +2. Linux Support + +Linux currently supports the following features on the IXP2000 NPUs: + +- On-chip serial +- PCI +- Flash (MTD/JFFS2) +- I2C through GPIO +- Timers (watchdog, OS) + +That is about all we can support under Linux ATM b/c the core networking +components of the chip are accessed via Intel's closed source SDK. +Please contact Intel directly on issues with using those. There is +also a mailing list run by some folks at Princeton University that might +be of help: https://lists.cs.princeton.edu/mailman/listinfo/ixp2xxx + +WHATEVER YOU DO, DO NOT POST EMAIL TO THE LINUX-ARM OR LINUX-ARM-KERNEL +MAILING LISTS REGARDING THE INTEL SDK. + +3. Supported Platforms + +- Intel IXDP2400 Reference Platform +- Intel IXDP2800 Reference Platform +- Intel IXDP2401 Reference Platform +- Intel IXDP2801 Reference Platform +- RadiSys ENP-2611 + +4. Usage Notes + +- The IXP2000 platforms usually have rather complex PCI bus topologies + with large memory space requirements. In addition, b/c of the way the + Intel SDK is designed, devices are enumerated in a very specific + way. B/c of this this, we use "pci=firmware" option in the kernel + command line so that we do not re-enumerate the bus. + +- IXDP2x01 systems have variable clock tick rates that we cannot determine + via HW registers. The "ixdp2x01_clk=XXX" cmd line options allow you + to pass the clock rate to the board port. + +5. Thanks + +The IXP2000 work has been funded by Intel Corp. and MontaVista Software, Inc. + +The following people have contributed patches/comments/etc: + +Naeem F. Afzal +Lennert Buytenhek +Jeffrey Daly + +------------------------------------------------------------------------- +Last Update: 8/09/2004 diff --git a/Documentation/arm/IXP4xx b/Documentation/arm/IXP4xx new file mode 100644 index 00000000000..d4c6d3aa0c2 --- /dev/null +++ b/Documentation/arm/IXP4xx @@ -0,0 +1,174 @@ + +------------------------------------------------------------------------- +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 + +DO NOT POST QUESTIONS TO THE LINUX MAILING LISTS REGARDING THE PROPIETARY +SOFTWARE. + +There are several websites that provide directions/pointers on using +Intel's software: + +http://ixp4xx-osdg.sourceforge.net/ + 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 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 +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/avila_sbc.htm + + 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://developer.intel.com/design/network/products/npfamily/ixdp425.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://developer.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/datasheet/PrPMC1100.pdf + + 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. + +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 diff --git a/Documentation/arm/Interrupts b/Documentation/arm/Interrupts new file mode 100644 index 00000000000..72c93de8cd4 --- /dev/null +++ b/Documentation/arm/Interrupts @@ -0,0 +1,173 @@ +2.5.2-rmk5 +---------- + +This is the first kernel that contains a major shake up of some of the +major architecture-specific subsystems. + +Firstly, it contains some pretty major changes to the way we handle the +MMU TLB. Each MMU TLB variant is now handled completely separately - +we have TLB v3, TLB v4 (without write buffer), TLB v4 (with write buffer), +and finally TLB v4 (with write buffer, with I TLB invalidate entry). +There is more assembly code inside each of these functions, mainly to +allow more flexible TLB handling for the future. + +Secondly, the IRQ subsystem. + +The 2.5 kernels will be having major changes to the way IRQs are handled. +Unfortunately, this means that machine types that touch the irq_desc[] +array (basically all machine types) will break, and this means every +machine type that we currently have. + +Lets take an example. On the Assabet with Neponset, we have: + + GPIO25 IRR:2 + SA1100 ------------> Neponset -----------> SA1111 + IIR:1 + -----------> USAR + IIR:0 + -----------> SMC9196 + +The way stuff currently works, all SA1111 interrupts are mutually +exclusive of each other - if you're processing one interrupt from the +SA1111 and another comes in, you have to wait for that interrupt to +finish processing before you can service the new interrupt. Eg, an +IDE PIO-based interrupt on the SA1111 excludes all other SA1111 and +SMC9196 interrupts until it has finished transferring its multi-sector +data, which can be a long time. Note also that since we loop in the +SA1111 IRQ handler, SA1111 IRQs can hold off SMC9196 IRQs indefinitely. + + +The new approach brings several new ideas... + +We introduce the concept of a "parent" and a "child". For example, +to the Neponset handler, the "parent" is GPIO25, and the "children"d +are SA1111, SMC9196 and USAR. + +We also bring the idea of an IRQ "chip" (mainly to reduce the size of +the irqdesc array). This doesn't have to be a real "IC"; indeed the +SA11x0 IRQs are handled by two separate "chip" structures, one for +GPIO0-10, and another for all the rest. It is just a container for +the various operations (maybe this'll change to a better name). +This structure has the following operations: + +struct irqchip { + /* + * Acknowledge the IRQ. + * If this is a level-based IRQ, then it is expected to mask the IRQ + * as well. + */ + void (*ack)(unsigned int irq); + /* + * Mask the IRQ in hardware. + */ + void (*mask)(unsigned int irq); + /* + * Unmask the IRQ in hardware. + */ + void (*unmask)(unsigned int irq); + /* + * Re-run the IRQ + */ + void (*rerun)(unsigned int irq); + /* + * Set the type of the IRQ. + */ + int (*type)(unsigned int irq, unsigned int, type); +}; + +ack - required. May be the same function as mask for IRQs + handled by do_level_IRQ. +mask - required. +unmask - required. +rerun - optional. Not required if you're using do_level_IRQ for all + IRQs that use this 'irqchip'. Generally expected to re-trigger + the hardware IRQ if possible. If not, may call the handler + directly. +type - optional. If you don't support changing the type of an IRQ, + it should be null so people can detect if they are unable to + set the IRQ type. + +For each IRQ, we keep the following information: + + - "disable" depth (number of disable_irq()s without enable_irq()s) + - flags indicating what we can do with this IRQ (valid, probe, + noautounmask) as before + - status of the IRQ (probing, enable, etc) + - chip + - per-IRQ handler + - irqaction structure list + +The handler can be one of the 3 standard handlers - "level", "edge" and +"simple", or your own specific handler if you need to do something special. + +The "level" handler is what we currently have - its pretty simple. +"edge" knows about the brokenness of such IRQ implementations - that you +need to leave the hardware IRQ enabled while processing it, and queueing +further IRQ events should the IRQ happen again while processing. The +"simple" handler is very basic, and does not perform any hardware +manipulation, nor state tracking. This is useful for things like the +SMC9196 and USAR above. + +So, what's changed? + +1. Machine implementations must not write to the irqdesc array. + +2. New functions to manipulate the irqdesc array. The first 4 are expected + to be useful only to machine specific code. The last is recommended to + only be used by machine specific code, but may be used in drivers if + absolutely necessary. + + set_irq_chip(irq,chip) + + Set the mask/unmask methods for handling this IRQ + + set_irq_handler(irq,handler) + + Set the handler for this IRQ (level, edge, simple) + + set_irq_chained_handler(irq,handler) + + Set a "chained" handler for this IRQ - automatically + enables this IRQ (eg, Neponset and SA1111 handlers). + + set_irq_flags(irq,flags) + + Set the valid/probe/noautoenable flags. + + set_irq_type(irq,type) + + Set active the IRQ edge(s)/level. This replaces the + SA1111 INTPOL manipulation, and the set_GPIO_IRQ_edge() + function. Type should be one of the following: + + #define IRQT_NOEDGE (0) + #define IRQT_RISING (__IRQT_RISEDGE) + #define IRQT_FALLING (__IRQT_FALEDGE) + #define IRQT_BOTHEDGE (__IRQT_RISEDGE|__IRQT_FALEDGE) + #define IRQT_LOW (__IRQT_LOWLVL) + #define IRQT_HIGH (__IRQT_HIGHLVL) + +3. set_GPIO_IRQ_edge() is obsolete, and should be replaced by set_irq_type. + +4. Direct access to SA1111 INTPOL is depreciated. Use set_irq_type instead. + +5. A handler is expected to perform any necessary acknowledgement of the + parent IRQ via the correct chip specific function. For instance, if + the SA1111 is directly connected to a SA1110 GPIO, then you should + acknowledge the SA1110 IRQ each time you re-read the SA1111 IRQ status. + +6. For any child which doesn't have its own IRQ enable/disable controls + (eg, SMC9196), the handler must mask or acknowledge the parent IRQ + while the child handler is called, and the child handler should be the + "simple" handler (not "edge" nor "level"). After the handler completes, + the parent IRQ should be unmasked, and the status of all children must + be re-checked for pending events. (see the Neponset IRQ handler for + details). + +7. fixup_irq() is gone, as is include/asm-arm/arch-*/irq.h + +Please note that this will not solve all problems - some of them are +hardware based. Mixing level-based and edge-based IRQs on the same +parent signal (eg neponset) is one such area where a software based +solution can't provide the full answer to low IRQ latency. + diff --git a/Documentation/arm/Netwinder b/Documentation/arm/Netwinder new file mode 100644 index 00000000000..f1b457fbd3d --- /dev/null +++ b/Documentation/arm/Netwinder @@ -0,0 +1,78 @@ +NetWinder specific documentation +================================ + +The NetWinder is a small low-power computer, primarily designed +to run Linux. It is based around the StrongARM RISC processor, +DC21285 PCI bridge, with PC-type hardware glued around it. + +Port usage +========== + +Min - Max Description +--------------------------- +0x0000 - 0x000f DMA1 +0x0020 - 0x0021 PIC |