Re: [Qemu-devel] [PATCH 0/9] Add platform bus

[François Revol]

On 23/07/2013 14:19, Paolo Bonzini wrote:
> Il 22/07/2013 20:21, Peter Maydell ha scritto:
>>>> >> > Platforms without ISA and/or PCI have had a seriously hard time in 
>>>> >> > the dynamic
>>>> >> > device creation world of QEMU. Devices on these were modeled as 
>>>> >> > SysBus devices
>>>> >> > which can only be instantiated in machine files, not through -device.
>>>> >> >
>>>> >> > Why is that so?
>> > Because you can't as a user of this sort of hardware
>> > plug in an extra serial port to a SoC, because there's just nowhere
>> > to plug it in. So why should it be possible to plug an extra
>> > serial port into the QEMU model of the SoC?
> And why exactly should QEMU be limited to modeling an existing SoC?
> 
> Perhaps the user is not working with an existing SoC.  They are working
> with with IP building blocks that they can combine the way they prefer,
> and they haven't yet made up their mind on the exact set of devices
> they'll have.  (because not all the world is a PC, but then not all the
> non-PC world is ARM either).
> 
> Perhaps the user is working on kernel support for device tree / ACPI,
> wants to test many device combinations, and does not want to touch C
> code in order to do that.

For what it's worth, ont sure it matters here, but the Sam460ex (PPC)
(I've been writing code to support it recently) has an FDT, and a PCI
controller...
And there is a firmware setting to switch between the 2nd SATA port and
the PCI-e slot as they are mutually exclusive...

François.