Messages in this thread |  | | | Date | Sat, 7 Aug 1999 16:17:51 +0200 | | From | Benjamin Herrenschmidt <> | | Subject | Re: New resources - pls, explain :-( |
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On Fri, Aug 6, 1999, Martin Mares <mj@atrey.karlin.mff.cuni.cz> wrote:
>> Think of PCI super-IO devices, for example. > > BTW have you ever seen such a chip? I never had...
On PowerMacs, for example, Apple's mac-io family of controllers are big PCI devices containing at least an interrupt controller, a bunch of DMA channels, a floppy controller, a VIA, a SCSI controller, a pair of SCCs and an ethernet controller ;-)
Some of those pieces can be shared between different versions of the chip, are handled by different drivers, etc... They are almost completely independant.
This case is correctly handled by the hierarchical nature of Open Firmware's device tree, and this requires the ability to use sub-regions made from the original PCI region (in this case, one big i/o mapped region in the PCI config space of the chip).
Note that it may be interesting to setup a way to automatically build all the region structures from the OF device tree on PowerMacs and CHRP machines, and then fixup the result with missing PCI cards (I heard that some rare cards won't be visible to OF at all, which looks stranges and contradicts OF theorical behaviour, but...) Note that this may already be done, I didn't check vger 2.3 for a while...
-- E-Mail: <mailto:bh40@calva.net> BenH. Web : <http://calvaweb.calvacom.fr/bh40/>
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