Notes on porting the NetBSD to ACube Sam4x0 boards
The NetBSD does not work on Sam4x0 boards yet. The work on this port has not started yet. This documment tries to summarize what should be done.
Missing support for PPC 440 cores
Main problem is that PowerPC 440 core are not supported yet. Both Sam440ep and Sam460ex are based on SoC chips with 440 core.
See Matt's mail.
Missing 440 support should fit into exisiting Book E support.
Firmware
Sam4x0 boards use U-Boot firmware, it is stored in a Flash chip. ACube provides source to Parthenope boot loader that can be used to boot AmigaOS 4, AROS and Linux. We should extend the Parthenope to support the NetBSD disk labels and filesystems (on RDB too). Alternatively, we could port altboot loader used with NetBSD/sandpoint.
For development work it should be possible to boot the NetBSD kernel directly with U-Boot TFTP.
Early console support
- PPC440EP has 16550 compatible UARTs built in. UART0 is at 0 EF60 0300 (8 bytes).
- PPC460EX has 16750 compatible UARTs built in. UART0 is at 4 EF60 0300 (8 bytes).
Docs
PPC440G5 Processor User's Manual
IBM PowerPC 440 Microprocessor Core Programming Model Overview
Differences between Book E and PPC440