[LinuxBIOS] another question for cs5536

Tom Sylla tsylla at gmail.com
Thu Jul 5 18:14:55 CEST 2007

On 7/5/07, Songmao Tian <tiansm at lemote.com> wrote:
> with regard to interrupt signal, I am still puzzled with the PCI_INTA#,
> it is said that it's a input io. Shouldn't it output the interrupt
> signal to cpu?

On 5536, the PCI_INT{A,B,C,D}# signals are usually configured as
inputs. (they are all just part of the GPIO block). Those signals then
get mapped into the interrupt logic through the various IRQ mapping

Interrupt delivery to the processor is done on the "CIS" pin that is
an output from 5536 to the GX or LX processor. The CIS pin delivers
IRQ, SMI, NMI, etc in a serial stream to the CPU. (the CPU
de-serializes it, and has internal versions of those signals)

Your goal seems to be to mux 5536's internal INTR signal out onto a
GPIO. There are some hints about that in the datasheet, but that is
not an official way to do it. Normal Geode systems all use the serial
packet. You will probably not get any support from AMD to do it that
way, that path is not tested. (though I have seen it work)

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