fdformat and netboot support

Hi,

As seen on source-changes@ and src/doc/CHANGES,
following two stuff has been added to NetBSD/x68k -current:

 1. network bootloader via Neptune-X and Nereid Ethernet
 2. formatting floppy support

I've also sent pullup requests for both changes,
and netboot works properly even on XM6i emulator ;-)
 http://twitpic.com/b2tl9w

These functions have been implemented/debugged to exhibit
Isaki's X68000 PRO-II with Xellent30 (which requires
netboot to run NetBSD/x68k due to lack of SxSI I/F support)
on NetBSD booth at Open Source Conference 2012 Hiroshima:
 http://twitpic.com/b6gs48
 http://togetter.com/li/392778

Details:

1. network bootloader via Neptune-X and Nereid Ethernet

http://mail-index.NetBSD.org/source-changes/2012/10/12/msg037830.html

While netboot support was added to the secondary bootloader
(now installed in /usr/mdec/netboot), X68K's IPL ROM doesn't
support network boot, so the secondary bootloader needs
to be loaded from SCSI hard drive or floppy disk.

To use netboot via floppy, you have to prepare a bootable floppy
with the new netboot loader as following:
---
# fdformat -f /dev/rfd0c
 (note newer fdformat support was mentioned later)
 :
# newfs -I /dev/rfd0c
 :
# /usr/mdec/newdisk -v /dev/rfd0c
 :
# /usr/mdec/installboot -v /usr/mdec/xxboot_ufs /dev/rfd0c
 :
# mount /dev/fd0c /mnt
# cp /usr/mdec/netboot /mnt/boot
 (note the primary xxboot_ufs always assumes /boot, not /netboot)

The netboot loader automatically checks Neptune-X and Nereid,
and use first found one to boot via DHCP and NFS.

There is no x68k specific netboot document (yet), but
generic DHCP and NFS server settings are applicable:
http://www.NetBSD.org/docs/network/netboot/index.html
http://www.NetBSD.org/docs/network/netboot/dhcpd.html
http://www.NetBSD.org/docs/network/netboot/nfs.html

2. formatting floppy support

http://mail-index.NetBSD.org/source-changes/2012/10/14/msg037911.html

Since x68k uses uPD765A FDC as x86 PC, so adding format support
was trivial though it required several DMAC driver bug fixes.

fdformat(8) command has been installed even on 6.0 so
you can use following commands once after you update your kernel:
- To format 2HC (512 bytes/sector, 15 sectors/track): 
   # fdformat -f /dev/rfd0c
- To format Japanese 2HD (1024 bytes/sector, 8 sectors/track): 
   # fdformat -f /dev/rfd0a
"/dev/rfd0b" can be used for 1.44MB 2HD format but it required
supported drives (internal drives need some hardware mods to use 1.44M).

Have fun,
---
Izumi Tsutsui