PCI target implementation on AMCC PPC CPUs

[sdeven.lee]

David Hawkins,您好！

	I have been finished an application using AMCC PPC440GP as PCI target(slave) in the last 2 month.I use a non-transparent bridge(AMCC PCI6466) to make the device a target(slave) like david has said.

======= 2007-09-07 04:26:01 您在来信中写道：=======

>Hi Leonid,
>
>In case they are not in the document:
>
>There are several fundamental problems with the AMCC 440EP
>acting as a PCI target/slave;
>
>1. As a PCI target, there is only one way to generate
>    an interrupt to a host; you basically toggle the
>    interrupt pin. This makes it tricky to develop a
>    host-to-slave communications protocol, eg. its
>    hard to use the single interrupt to indicate various
>    interrupt states, eg. target-to-host buffer has
>    data versus host-to-target buffer has been emptied.
>    Ideally AMCC should have implemented mailboxes and/or
>    doorbell registers like any other sane PCI target
>    device (eg. some the Freescale processors, or any of
>    the PLX technologies chips).
>
>2. Look in the data sheet and see if you can figure out
>    how the host processor can generate an interrupt to
>    the PowerPC core ... oops, you can't. That kind of
>    makes it difficult to work with doesn't it.
>
>    A work around would be to have the host write to the
>    GPIO register and wire a GPIO pin back to an external
>    interrupt pin. Then you would not be able to use any
>    other GPIO pin in that GPIO register since there is
>    no way to arbitrate host access versus PowerPC core
>    access.
>
>This was the other reason I ditched the AMCC part in
>favor of the Freescale part.
>
>If you are looking at other parts, make sure you look
>in the PCI configuration space of the processor reference
>manual. Many processors have the interrupt pin register
>hardwired to zero, i.e., they can not be used as target
>devices, only hosts. In that case you'd have to add an
>intel 21555 non-transparent bridge to make the device
>a target.
>
>Cheers,
>Dave
>
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　　　　　　　　致
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　　　　　　　　sdeven.lee
　　　　　　　　sdeven.lee at 163.com
　　　　　　　　　　2007-09-07