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Re: My Introduction / How PPB claim configtype1 cycles
Hallo Jürgen,
It's a while since I worked on PCI, but as far as I remember the scenario is the
following:
First of all the host configures all Bus-0 agents, including the bridges, it can
find (conifg type 0 cycles).
If it encounters a bridge or bridges, it will assign bus-numbers to the first bus
found behind each bridge.
Once this is done it will start looking for bus-agents attached to the secondary
bridges by running config type one cycles.
A config type 1 cycle has the LSB (bit 2e0) set to one. The bridge controlling the
required secondary bus will convert a type 1 cycle to a type 0 cycle. All other
bridges will pass a type 1 cycle through unchanged in case there are any further
bridges behind the first level.
The best source of info I found was the (expensive) PCI book from Solari/Wilkes.
Hope this helps
Rgards,
Charles
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