Linux on the CRIS architecture
  ==============================

  This is a port of Linux to Axis Communications ETRAX 100LX,
  ETRAX FS and ARTPEC-3 embedded network CPUs.
  
  For more information about CRIS and ETRAX please see further below.

  
  In order to compile this you need a version of gcc with support for the

  ETRAX chip family. Please see this link for more information on how to

  download the compiler and other tools useful when building and booting
  software for the ETRAX platform:

  http://developer.axis.com/wiki/doku.php?id=axis:install-howto-2_20

  
  What is CRIS ?
  --------------
  
  CRIS is an acronym for 'Code Reduced Instruction Set'. It is the CPU
  architecture in Axis Communication AB's range of embedded network CPU's,

  called ETRAX.

  
  The ETRAX 100LX chip
  --------------------

  For reference, please see the following link:

  http://www.axis.com/products/dev_etrax_100lx/index.htm

  The ETRAX 100LX is a 100 MIPS processor with 8kB cache, MMU, and a very broad
  range of built-in interfaces, all with modern scatter/gather DMA.

  
  Memory interfaces:
  
  	* SRAM
  	* NOR-flash/ROM
  	* EDO or page-mode DRAM
  	* SDRAM
  
  I/O interfaces:
  
  	* one 10/100 Mbit/s ethernet controller
  	* four serial-ports (up to 6 Mbit/s)
  	* two synchronous serial-ports for multimedia codec's etc.
  	* USB host controller and USB slave
  	* ATA
  	* SCSI
  	* two parallel-ports
  	* two generic 8-bit ports

  
  	(not all interfaces are available at the same time due to chip pin

           multiplexing)

  ETRAX 100LX is CRISv10 architecture.
  
  
  The ETRAX FS and ARTPEC-3 chips
  -------------------------------

  The ETRAX FS is a 200MHz 32-bit RISC processor with on-chip 16kB
  I-cache and 16kB D-cache and with a wide range of device interfaces
  including multiple high speed serial ports and an integrated USB 1.1 PHY.

  The ARTPEC-3 is a variant of the ETRAX FS with additional IO-units
  used by the Axis Communications network cameras.
  
  See below link for more information:
  
  http://www.axis.com/products/dev_etrax_fs/index.htm
  
  ETRAX FS and ARTPEC-3 are both CRISv32 architectures.

  
  Bootlog
  -------
  
  Just as an example, this is the debug-output from a boot of Linux 2.4 on
  a board with ETRAX 100LX. The displayed BogoMIPS value is 5 times too small :)
  At the end you see some user-mode programs booting like telnet and ftp daemons.
  
  Linux version 2.4.1 (bjornw@godzilla.axis.se) (gcc version 2.96 20000427 (experimental)) #207 Wed Feb 21 15:48:15 CET 2001
  ROM fs in RAM, size 1376256 bytes
  Setting up paging and the MMU.
  On node 0 totalpages: 2048
  zone(0): 2048 pages.
  zone(1): 0 pages.
  zone(2): 0 pages.
  Linux/CRIS port on ETRAX 100LX (c) 2001 Axis Communications AB
  Kernel command line: 
  Calibrating delay loop... 19.91 BogoMIPS
  Memory: 13872k/16384k available (587k kernel code, 2512k reserved, 44k data, 24k init)
  kmem_create: Forcing size word alignment - vm_area_struct
  kmem_create: Forcing size word alignment - filp
  Dentry-cache hash table entries: 2048 (order: 1, 16384 bytes)
  Buffer-cache hash table entries: 2048 (order: 0, 8192 bytes)
  Page-cache hash table entries: 2048 (order: 0, 8192 bytes)
  kmem_create: Forcing size word alignment - kiobuf
  kmem_create: Forcing size word alignment - bdev_cache
  Inode-cache hash table entries: 1024 (order: 0, 8192 bytes)
  kmem_create: Forcing size word alignment - inode_cache
  POSIX conformance testing by UNIFIX
  Linux NET4.0 for Linux 2.4
  Based upon Swansea University Computer Society NET3.039
  Starting kswapd v1.8
  kmem_create: Forcing size word alignment - file lock cache
  kmem_create: Forcing size word alignment - blkdev_requests
  block: queued sectors max/low 9109kB/3036kB, 64 slots per queue
  ETRAX 100LX 10/100MBit ethernet v2.0 (c) 2000 Axis Communications AB
  eth0 initialized
  eth0: changed MAC to 00:40:8C:CD:00:00
  ETRAX 100LX serial-driver $Revision: 1.7 $, (c) 2000 Axis Communications AB
  ttyS0 at 0xb0000060 is a builtin UART with DMA
  ttyS1 at 0xb0000068 is a builtin UART with DMA
  ttyS2 at 0xb0000070 is a builtin UART with DMA
  ttyS3 at 0xb0000078 is a builtin UART with DMA
  Axis flash mapping: 200000 at 50000000
  Axis flash: Found 1 x16 CFI device at 0x0 in 16 bit mode
   Amd/Fujitsu Extended Query Table v1.0 at 0x0040
  Axis flash: JEDEC Device ID is 0xC4. Assuming broken CFI table.
  Axis flash: Swapping erase regions for broken CFI table.
  number of CFI chips: 1
   Using default partition table
  I2C driver v2.2, (c) 1999-2001 Axis Communications AB
  ETRAX 100LX GPIO driver v2.1, (c) 2001 Axis Communications AB
  NET4: Linux TCP/IP 1.0 for NET4.0
  IP Protocols: ICMP, UDP, TCP
  kmem_create: Forcing size word alignment - ip_dst_cache
  IP: routing cache hash table of 1024 buckets, 8Kbytes
  TCP: Hash tables configured (established 2048 bind 2048)
  NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
  VFS: Mounted root (cramfs filesystem) readonly.
  Init starts up...
  Mounted none on /proc ok.
  Setting up eth0 with ip 10.13.9.116 and mac 00:40:8c:18:04:60
  eth0: changed MAC to 00:40:8C:18:04:60
  Setting up lo with ip 127.0.0.1
  Default gateway is 10.13.9.1
  Hostname is bbox1
  Telnetd starting, using port 23.
    using /bin/sash as shell.
  sftpd[15]: sftpd $Revision: 1.7 $ starting up
  
  
  
  And here is how some /proc entries look:
  
  17# cd /proc
  17# cat cpuinfo
  cpu             : CRIS
  cpu revision    : 10
  cpu model       : ETRAX 100LX
  cache size      : 8 kB
  fpu             : no
  mmu             : yes
  ethernet        : 10/100 Mbps
  token ring      : no
  scsi            : yes
  ata             : yes
  usb             : yes
  bogomips        : 99.84
  
  17# cat meminfo
          total:    used:    free:  shared: buffers:  cached:
  Mem:   7028736   925696  6103040   114688        0   229376
  Swap:        0        0        0
  MemTotal:         6864 kB
  MemFree:          5960 kB
  MemShared:         112 kB
  Buffers:             0 kB
  Cached:            224 kB
  Active:            224 kB
  Inact_dirty:         0 kB
  Inact_clean:         0 kB
  Inact_target:        0 kB
  HighTotal:           0 kB
  HighFree:            0 kB
  LowTotal:         6864 kB
  LowFree:          5960 kB
  SwapTotal:           0 kB
  SwapFree:            0 kB
  17# ls -l /bin
  -rwxr-xr-x  1 342      100         10356  Jan 01 00:00 ifconfig
  -rwxr-xr-x  1 342      100         17548  Jan 01 00:00 init
  -rwxr-xr-x  1 342      100          9488  Jan 01 00:00 route
  -rwxr-xr-x  1 342      100         46036  Jan 01 00:00 sftpd
  -rwxr-xr-x  1 342      100         48104  Jan 01 00:00 sh
  -rwxr-xr-x  1 342      100         16252  Jan 01 00:00 telnetd