Re: [Qemu-devel] [Qemu-ppc] [PATCH] e500-pci: Factor into distinct mpc8540 and p4080 PCI Hosts

[Ben Collins]

On May 31, 2012, at 2:20 PM, Scott Wood wrote:

> On 05/30/2012 06:25 PM, Ben Collins wrote:
>> In order to provide a closer virtualization, factor out e500-pci into 
>> seperate
>> PCI hosts, namely fsl,mpc8540-pci and fsl,p4080-pcie (to match the 
>> device-tree
>> node naming).
>> 
>> Make use of the mpc8540 variant (basically a NOP) for ppce500_mpc8544 machine
>> type. The p4080-pcie variant can be used later for a P4080DS specific machine
>> description.
>> 
>> The major differences between the two are the host-bridge PCI device ID and 
>> the
>> difference in starting slot number. Eventually I'd like to get the p4080 
>> variant
>> to support any valid slot number, and actually move the bus behind the host
>> bridge as is done in the physical hardware.
> 
> Do these really need to be totally separate implementations?  If we then
> want to support another FSL PPC chip's PCI that has some subtle
> differences, do we need a third?  If the emulation of these host bridges
> is made more complete, we'll have to add that code to every one of these
> forks.
> 
> I'd rather see one driver that is parameterizable to implement any
> mpc85xx/mpc86xx/QorIQ PCI(e).


I'm completely ok with that. My original intent was to remove the limitations 
of the e500-pci driver, but Alexander had reservations about making the 
mpc8540-pci implementation non-compliant to the original hardware. My main goal 
is to make it so users (and myself) don't have to be limited by this 
lowest-common-denominator (2-4 PCI slots, forced at 0x17 starting point).

I'll look into making this configurable. Are there any current PCI 
implementations that allow for such configurability that I can base work on?

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