Re: [PATCH] Intel IXP4xx network drivers v.2 - Ethernet and HSS

On Tue, 8 May 2007 08:22:17 +0100, Michael-Luke Jones wrote:

On 8 May 2007, at 02:19, Krzysztof Halasa wrote:

quoted

Adds a driver for built-in IXP4xx Ethernet MAC and HSS ports

...

quoted

+#ifndef __ARMEB__
+#warning Little endian mode not supported
+#endif

This has gone from error to warning - fair play but if are planning  
to put this upstream this cycle (anything's possible :) ) you'll want  
to declare this driver broken on ARMEB in Kconfig please.

Personally I'd like LE ethernet tested and working before we push.

AFAIK, it's a HW limitation of the IXP4xx NPEs, or
possibly Intel's microcode for them.

I run my IXP42x boxes big-endian and don't mind doing so.

/Mikael

On 8 May 2007, at 09:26, Mikael Pettersson wrote:

On Tue, 8 May 2007 08:22:17 +0100, Michael-Luke Jones wrote:
AFAIK, it's a HW limitation of the IXP4xx NPEs, or
possibly Intel's microcode for them.

I run my IXP42x boxes big-endian and don't mind doing so.

/Mikael

*cough*
http://www.hohnstaedt.de/ixp_npe/0.2.0/0001-IXP4XX-Driver-for-NPE- 
QMGR-MAC-0.2.0.txt
:p

---

On 8 May 2007, at 09:29, Tomasz Chmielewski wrote:

Christian Hohnstaedt's work did support LE though.

Indeed.

Krzysztof, why is LE not supported?

Butting in here. It's not supported because LE mode has to work in a  
brain-damaged way. NPE DMAs the complete skb straight out of RAM.  
Unfortunately it expects the skb to already be written out in ram BE.

Thus, in LE mode we have to byteswap the skb with CPU before the NPE  
can DMA it. This hasn't been implemented yet.

Michael-Luke Jones