# Notes on porting the NetBSD to ACube Sam4x0 boards

The NetBSD does not work on [[Sam4x0|http://www.sam4x0.com/]] 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|http://mail-index.netbsd.org/port-powerpc/2012/08/09/msg003224.html]].

Missing 440 support should fit into exisiting
[[Book E support|http://nxr.netbsd.org/xref/src/sys/arch/powerpc/booke/]].

## Firmware

Sam4x0 boards use U-Boot firmware, it is stored in a Flash chip. ACube provides
[[source|http://www.acube-systems.biz/download/ub2lb-0.93.zip]] 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|http://c0ff33.net/drop/PPC440_UM2013.pdf]]

[[Sam460ex U-Boot boot log|http://c0ff33.net/drop/ppc460ex.txt]]

[[IBM PowerPC 440 Microprocessor Core Programming Model Overview|http://alacron.com/clientuploads/PDFs/forweb/440_Programming_Model.pdf]]

[[Differences between Book E and PPC440|http://elinux.org/Book_E_and_PPC_440]]