haiku/docs/develop/kernel/arch/arm/rpi1.md

# Raspberry Pi
* http://raspberrypi.org

# Hardware Information

* ARMv6 Architecture
* Broadcom BCM2835 (SoC)
  * Includes ARM1176JZF-S CPU @ 700 MHz
  * Includes VideoCore IV GPU
* SD Card Storage
* 256 or 512 MB RAM (depending on revision)
* Video Outputs
  * HDMI Video Output
  * Composite Video Output
* Ethernet

# Setting up the Haiku SD card

The Raspberry Pi SD card generally uses the MBR file system layout below. Partition 1 is all that is required to boot an OS.

*  partition 1 -- FAT32, bootable flag, type 'c'
*  partition 2 -- BeFS, Haiku filesystem, type 'eb'

## Boot Partition

### Required Files

*  bootcode.bin : 2nd stage bootloader
*  start.elf: The GPU binary firmware image
*  config.txt: A configuration file read by the Pi to start u-boot.bin
*  u-boot.bin: u-boot loader for the Pi 2
*  bcm2835-rpi-b.dtb: FDT binary for the Raspberry Pi 2
*  haiku_loader_linux.ub: Haiku Loader
*  haiku-floppyboot.tgz.ub: Compressed initial ram image with Haiku kernel

### Optional Files

*  vlls directory: Additional GPU code, e.g. extra codecs.
*  uEnv.txt: u-boot configuration script to automate boot.

# Compiling

*  Create your ARM work directory `mkdir generated.arm; cd generated.arm`
*  Build an ARM toolchain using `../configure --build-cross-tools arm ../../buildtools --target-board=rpi1`
*  Build our loader using `jam -q haiku_loader_linux.ub`
*  Build our initial ram disk using `jam -q haiku-floppyboot.tgz.ub`

# Booting

1. SOC finds bootcode.bin
2. bootcode.bin runs start.elf
3. start.elf reads config.txt and start u-boot
4. u-boot.bin starts the Haiku loader
5. Haiku loader boots Haiku kernel

## config.txt Options

    kernel=u-boot.bin

## u-boot startup

These will be condensed and automated long-term via uEnv.txt :-)

* `fatload mmc 0 ${fdt_addr_r} bcm2835-rpi-b.dtb`
* `fdt addr ${fdt_addr_r}`
* `fatload mmc 0 ${ramdisk_addr_r} haiku-floppyboot.tgz.ub`
* `fatload mmc 0 ${kernel_addr_r} haiku_loader_linux.ub`
* `bootm ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr_r}`

# Additional Information

* [Latest Raspberry Pi firmware](http://github.com/raspberrypi/firmware/tree/master/boot)
* [config.txt options](http://www.elinux.org/RPiconfig)