Purpose of pci_remap_iospace

On Friday, July 15, 2016 5:21:20 AM CEST Bharat Kumar Gogada wrote:

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On Thu, Jul 14, 2016 at 01:32:13PM +0000, Bharat Kumar Gogada wrote:

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Hi Lorenzo,

I missed something in my device tree now I corrected it.

ranges = <0x01000000 0x00000000 0xe0000000 0x00000000 0xe0000000 0

0x00010000   //io

You have not missed anything, you changed the PCI bus address at which
your host bridge responds to IO space and it must match your configuration.
At what PCI bus address your host bridge maps IO space ?

Our host bridge does not have dedicted address space mapped for IO transactions.
For generation of IO transactions it requires some register read and write operations
in bridge logic.

So the above PCI address does not come in to picture also, is there alternate way to handle IO
Bars with our kind of hardware architecture.

Hisilicon has a similar thing on one of their LPC bridges, and
Rongrong Zou has implemented something for it in the past, but I
think it never got merged.

https://lkml.org/lkml/2015/12/29/154 has one version of his
proposal, not sure if that was the latest one or if something
newer exists.

	Arnd