Porting Linux

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Porting Linux

• Linux onto the Puppeteer SA1110

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The Puppeteer board

• The Puppeteer board
• SA1110 CPU
• SMSC LAN91C96I ethernet
• 8 Mb Flash Intel 28F320C3 Boot block flash
• 32 Mb DRAM
• Altera FPGA 6k
• Xilinks CPLD XCR3064A

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Selecting an OS

• Lots of choices
• NETBSD
• gcc problems good documentation
• Ecos
• Modular rt system
• Linux
• Various commercial versions
• Montavista, Yellowdog, blue cat
• Distributions
• Redhat, Debian
• Uclinux
• Arm has an MMU
• Build your own!
• 2.4.18 -gt 2.4.21

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Building the cross compiler

• Using gcc 2.95.3
• Going to 3.3 for 2.6.n kernels
• Binutils
• X
• Building own
• There are lots of toolchains around!

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Selecting a library

• Selecting a library for an embedded system
  requires care.
• Glibc
• GNU standard too large
• Newlib
• Good for embedded board without an OS/linux
• Uclibc
• Doesnt need Uclinux small well supported
• Good gcc support

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The native BSP

• Fairly large problem for porting
• Supports VxWorks
• Specialised command set no debug!
• Uses COFF/MSbin
• Does use standard tftp
• No documentation
• Had to create several tools
• Elf2bin
• Eloadsvr
• elf2data

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Building the kernel

• SA1110 is well supported
• Changes to board specifics
• Linux/arch/arm/head.s
• Serial port code esp. in linux/include

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Creating a rootfs

• Need to create rootfs on host
• dd to create empty 8mb file
• Mkfs.ext2 on it
• Mount o loop
• Create /dev /etc et al
• Type carefully!
• Needed converting into MSbin format yuk!

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Busybox tiny login

• Rather than build each tool, busybox and
  tinylogin were used
• Very good set of utilities
• Works well with uclibc
• Easy to configure
• Require some full scale tools
• TCP/IP tools
• Weird busybox error!

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TCP/IP NFS

• Had to port the SMC9194.c driver for board
• Find the chip!
• Re-write low level access routine
• FPGA interrupt handling routines
• Debugging!
• The importance of ARP
• NFS
• Requires some extra library support zlib
• Seems to work
• NFS mounted root fs doesnt work, yet!

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Remote debugging with GDB

• Using gdb version 6
• Seems to work well with uclibc
• untested

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MTD flash devices

• MTD is not supposed to be in sync with kernel
  seemed fine
• Using CFI
• Under 2.4.n have to put partitions into map file
  sa1110-flash.c
• 7MB available
• Boot block?
• Choice of file systems
• Weird mtd MAC address problem

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I2c and eeprom

• Due to the MTD/MAC problem I ported some
  transpond code for I2c eeprom to read the nv
  data
• Works in smc driver!
• I2c implemented as a linux driver not tested
• This is straying towards bsp/bios functionality

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Das Uboot

• Needs a new boot strap lots of choice
• Redboot, blob, angelboot,
• Using Uboot
• Well supported, small, modular
• Need to write FPGA support code
• Need I2c code
• How to install
• Jtag? ICE?

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