Subject: Re: Fwd: Located problem in pcn driver...
To: Jaromir Dolecek <email@example.com>
From: Bill Studenmund <firstname.lastname@example.org>
Date: 04/21/2003 14:59:58
On Fri, 18 Apr 2003, Jaromir Dolecek wrote:
> The address used for DMA is physical memory address. Do you say
> that PCI and CPU see different physical memory adresses? That's
> quite weird. Isn't it just bug in htole32() in handling of the
> MSB or somewhere in the DMA code?
No, the bus and the CPU can have different ideas about how memory is layed
out. That's why there is a lot of complexity in the bus_space code. When
Jason was at NASA, he was working with Alphas that have this issue, so he
worked it into bus_space.
And if you have multiple nested busses, it can get REAL messy. :-)