Subject: better sonic -- Re: bus_dma on jazzio
To: None <port-arc@netbsd.org, port-mipsco@netbsd.org>
From: Toru Nishimura <nisimura@itc.aist-nara.ac.jp>
List: port-arc
Date: 02/23/2001 12:05:55
In <20010222014530.S16385@mail.radicalmedia.com>
phiber@radicalmedia.com wrote:
> We may also consider making
> the sonic driver MI, since other archs (such as mac68k) make use of it.
Tic-tic-tic. Purse 32bit sane, endian neutral, RISC friendly driver
first, please. R4000 Magnum designer was very careful to populate
hardware registers useful in endian neutral way. For the target chip
register are 8bit-wise, they can be written in 0x......VV where upper
24bit bit value is "don't-care", and when read, upper 24bit value is
unpredictable and to be masked off before use. Then, as long as chip
registers are accessed 32bit (or 64bit) chunk, kernel can have few
endian dependency in the aspect.
Wayne, due to the way you wrote driver, NetBSD/mipsco for R3000 Magnum
is BE only. As you know the hardware can be booted in another endian.
NetBSD/mipsco could be useful in LE when rewritten.
BTW, NetBSD/mipsco is the most beautifully implemented MIPS NetBSD.
When you guys start another MIPS port, look at it first and stale the
code from there. NetBSD/pmax is the worst example (I admit...)
Tohru Nishimura