FreeBSD/Linux Kernel Cross Reference
sys/Documentation/arm/

	Name	Size	Last modified (GMT)	Description
	Parent directory		2013-02-02 13:13:18
	Marvell/		2013-02-02 13:13:53
	OMAP/		2013-02-02 13:13:52
	SA1100/		2013-02-02 13:13:53	SA1100 documentation
	SH-Mobile/		2013-02-02 13:13:52
	SPEAr/		2013-02-02 13:13:52
	Samsung/		2013-02-02 13:13:52
	Samsung-S3C24XX/		2013-02-02 13:13:53
	Sharp-LH/		2010-12-20 22:09:56
	VFP/		2013-02-02 13:13:52	Release notes for Linux Kernel Vector Floating Point support code
	empeg/		2008-07-09 15:43:18	Ltd's Empeg MP3 Car Audio Player
	msm/		2013-02-02 13:13:52
	nwfpe/		2013-02-02 13:13:52	NWFPE floating point emulator documentation
	pxa/		2013-02-02 13:13:52
	sunxi/		2013-02-02 13:13:52
	Booting	7108 bytes	2012-12-25 01:40:40	requirements for booting
	IXP2000	2378 bytes	2010-08-24 17:11:33
	IXP4xx	6453 bytes	2011-08-10 17:02:04
	Interrupts	6761 bytes	2008-12-11 08:29:13	ARM Interrupt subsystem documentation
	Netwinder	1509 bytes	2006-12-13 11:48:10	Netwinder specific documentation
	Porting	4488 bytes	2006-12-13 11:48:10
	README	7312 bytes	2010-08-24 17:11:33	General ARM documentation
	Setup	3571 bytes	2006-12-13 11:48:11
	kernel_user_helpers.txt	6715 bytes	2012-12-25 01:40:41
	mem_alignment	2494 bytes	2009-10-05 12:43:23	alignment abort handler documentation
	memory.txt	3416 bytes	2012-12-25 01:40:41	description of the virtual memory layout
	swp_emulation	1210 bytes	2011-08-10 17:02:04	SWP/SWPB emulation handler/logging description
	tcm.txt	5082 bytes	2010-08-24 17:11:33

                                ARM Linux 2.6
                                =============
     
         Please check <ftp://ftp.arm.linux.org.uk/pub/armlinux> for
         updates.
     
     Compilation of kernel
     ---------------------
     
      In order to compile ARM Linux, you will need a compiler capable of
      generating ARM ELF code with GNU extensions.  GCC 3.3 is known to be
      a good compiler.  Fortunately, you needn't guess.  The kernel will report
      an error if your compiler is a recognized offender.
    
      To build ARM Linux natively, you shouldn't have to alter the ARCH = line
      in the top level Makefile.  However, if you don't have the ARM Linux ELF
      tools installed as default, then you should change the CROSS_COMPILE
      line as detailed below.
    
      If you wish to cross-compile, then alter the following lines in the top
      level make file:
    
        ARCH = <whatever>
            with
        ARCH = arm
    
            and
    
        CROSS_COMPILE=
            to
        CROSS_COMPILE=<your-path-to-your-compiler-without-gcc>
            eg.
        CROSS_COMPILE=arm-linux-
    
      Do a 'make config', followed by 'make Image' to build the kernel 
      (arch/arm/boot/Image).  A compressed image can be built by doing a 
      'make zImage' instead of 'make Image'.
    
    
    Bug reports etc
    ---------------
    
      Please send patches to the patch system.  For more information, see
      http://www.arm.linux.org.uk/developer/patches/info.php Always include some
      explanation as to what the patch does and why it is needed.
    
      Bug reports should be sent to linux-arm-kernel@lists.arm.linux.org.uk,
      or submitted through the web form at
      http://www.arm.linux.org.uk/developer/ 
    
      When sending bug reports, please ensure that they contain all relevant
      information, eg. the kernel messages that were printed before/during
      the problem, what you were doing, etc.
    
    
    Include files
    -------------
    
      Several new include directories have been created under include/asm-arm,
      which are there to reduce the clutter in the top-level directory.  These
      directories, and their purpose is listed below:
    
       arch-*       machine/platform specific header files
       hardware     driver-internal ARM specific data structures/definitions
       mach         descriptions of generic ARM to specific machine interfaces
       proc-*       processor dependent header files (currently only two
                    categories)
    
    
    Machine/Platform support
    ------------------------
    
      The ARM tree contains support for a lot of different machine types.  To
      continue supporting these differences, it has become necessary to split
      machine-specific parts by directory.  For this, the machine category is
      used to select which directories and files get included (we will use
      $(MACHINE) to refer to the category)
    
      To this end, we now have arch/arm/mach-$(MACHINE) directories which are
      designed to house the non-driver files for a particular machine (eg, PCI,
      memory management, architecture definitions etc).  For all future
      machines, there should be a corresponding arch/arm/mach-$(MACHINE)/include/mach
      directory.
    
    
    Modules
    -------
    
      Although modularisation is supported (and required for the FP emulator),
      each module on an ARM2/ARM250/ARM3 machine when is loaded will take
      memory up to the next 32k boundary due to the size of the pages.
      Therefore, is modularisation on these machines really worth it?
    
      However, ARM6 and up machines allow modules to take multiples of 4k, and
      as such Acorn RiscPCs and other architectures using these processors can
      make good use of modularisation.
    
    
    ADFS Image files
   ----------------
   
     You can access image files on your ADFS partitions by mounting the ADFS
     partition, and then using the loopback device driver.  You must have
     losetup installed.
   
     Please note that the PCEmulator DOS partitions have a partition table at
     the start, and as such, you will have to give '-o offset' to losetup.
   
   
   Request to developers
   ---------------------
   
     When writing device drivers which include a separate assembler file, please
     include it in with the C file, and not the arch/arm/lib directory.  This
     allows the driver to be compiled as a loadable module without requiring
     half the code to be compiled into the kernel image.
   
     In general, try to avoid using assembler unless it is really necessary.  It
     makes drivers far less easy to port to other hardware.
   
   
   ST506 hard drives
   -----------------
   
     The ST506 hard drive controllers seem to be working fine (if a little
     slowly).  At the moment they will only work off the controllers on an
     A4x0's motherboard, but for it to work off a Podule just requires
     someone with a podule to add the addresses for the IRQ mask and the
     HDC base to the source.
   
     As of 31/3/96 it works with two drives (you should get the ADFS
     *configure harddrive set to 2). I've got an internal 20MB and a great
     big external 5.25" FH 64MB drive (who could ever want more :-) ).
   
     I've just got 240K/s off it (a dd with bs=128k); thats about half of what
     RiscOS gets; but it's a heck of a lot better than the 50K/s I was getting
     last week :-)
   
     Known bug: Drive data errors can cause a hang; including cases where
     the controller has fixed the error using ECC. (Possibly ONLY
     in that case...hmm).
   
   
   1772 Floppy
   -----------
     This also seems to work OK, but hasn't been stressed much lately.  It
     hasn't got any code for disc change detection in there at the moment which
     could be a bit of a problem!  Suggestions on the correct way to do this
     are welcome.
   
   
   CONFIG_MACH_ and CONFIG_ARCH_
   -----------------------------
     A change was made in 2003 to the macro names for new machines.
     Historically, CONFIG_ARCH_ was used for the bonafide architecture,
     e.g. SA1100, as well as implementations of the architecture,
     e.g. Assabet.  It was decided to change the implementation macros
     to read CONFIG_MACH_ for clarity.  Moreover, a retroactive fixup has
     not been made because it would complicate patching.
   
     Previous registrations may be found online.
   
       <http://www.arm.linux.org.uk/developer/machines/>
   
   Kernel entry (head.S)
   --------------------------
     The initial entry into the kernel is via head.S, which uses machine
     independent code.  The machine is selected by the value of 'r1' on
     entry, which must be kept unique.
   
     Due to the large number of machines which the ARM port of Linux provides
     for, we have a method to manage this which ensures that we don't end up
     duplicating large amounts of code.
   
     We group machine (or platform) support code into machine classes.  A
     class typically based around one or more system on a chip devices, and
     acts as a natural container around the actual implementations.  These
     classes are given directories - arch/arm/mach-<class> and
     arch/arm/mach-<class> - which contain the source files to/include/mach
     support the machine class.  This directories also contain any machine
     specific supporting code.
   
     For example, the SA1100 class is based upon the SA1100 and SA1110 SoC
     devices, and contains the code to support the way the on-board and off-
     board devices are used, or the device is setup, and provides that
     machine specific "personality."
   
     This fine-grained machine specific selection is controlled by the machine
     type ID, which acts both as a run-time and a compile-time code selection
     method.
   
     You can register a new machine via the web site at:
   
       <http://www.arm.linux.org.uk/developer/machines/>
   
   ---
   Russell King (15/03/2004)