Messages in this thread | | | Date | Sun, 15 Aug 1999 03:28:21 +0200 | From | Ralf Baechle <> | Subject | Re: New resources - pls, explain :-( |
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On Fri, Aug 13, 1999 at 02:36:10PM -0400, Peter Desnoyers wrote:
> The only cases I have insight into are PCI drivers, where the swapping > points on bigendian machines can be: > > - none, all device registers are little-endian > - on the motherboard, flip all memread32/memwrite32 but no DMA access > (the hardware folks at work believe this exists somewhere, but I haven't > seen it)
SNI's ASICPCI chipset used for example in the RM200C features 15 16mb windows for each of which byteorder swapping can be configured independantly.
We neither support such a mapping feature in our current APIs nor is having drivers rely on the presence of such a feature a good idea unless it's present in all machines of a certain architecture.
> - on the motherboard, selectable on a page-by-page basis (ultrasparc?) > - on the card - one or more areas can be configured to flip byte order > to big-endian > > I'm assuming that there are no PCI devices where device registers are > always big-endian. (is that true for all weird Mac cards?) Handling of > cases is:
The SGI IOC3 is one example for such a card. Registers in PCI config space are little endian as per PCI spec. Other registers are big endian.
Anybody PDP endian ;-)
Ralf
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