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Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root
From: |
Kevin O'Connor |
Subject: |
Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses. |
Date: |
Thu, 11 Jun 2015 10:24:25 -0400 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Thu, Jun 11, 2015 at 05:12:33PM +0300, Marcel Apfelbaum wrote:
> On 06/11/2015 04:58 PM, Kevin O'Connor wrote:
> >On Thu, Jun 11, 2015 at 04:37:08PM +0300, Marcel Apfelbaum wrote:
> >>The fixes solves the following issue:
> >>The PXB device exposes a new pci root bridge with the
> >>fw path: /address@hidden/..., in which 4 is the root bus number.
> >>Before this patch the fw path was wrongly computed:
> >> /address@hidden/address@hidden/...
> >>Fix the above issues: Correct the bus number and remove the
> >>extra host bridge description.
> >
> >Why is that wrong? The previous path looks correct to me.
> The prev path includes both the extra root bridge and *then* the usual host
> bridge.
> /address@hidden/address@hidden/ ...
> ^ new ^ regular ^ devices
>
> Since the new pci root bridge (and bus) is on "paralel" with the regular one.
> it is not correct to add it to the path.
>
> The architecture is:
> /<host bridge>/devices...
> /extra root bridge/devices...
> /extra root bridge/devices...
> And not
> /extra root bridge//<host bridge>/devices
Your patch changed both the "/extra root bridge/devices..." part and
the "@1" part. The change of the "@1" in "/address@hidden/" is not
correct IMO.
Does open-firmware have any examples for PCI paths and in particular
PCI paths when there are multiple root-buses?
It's possible to replace the "address@hidden" with "address@hidden" but that
seems odd as the extra root bus is accessible via io accesses to
0x0cf8.
Another option would be to place the address@hidden behind the address@hidden
as in "/address@hidden/address@hidden/...". Or, the root bus could be appended
to the host bridge as in "/address@hidden,1/...".
-Kevin
- [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses., Marcel Apfelbaum, 2015/06/11
- Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses., Laszlo Ersek, 2015/06/11
- Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses., Kevin O'Connor, 2015/06/11
- Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses., Marcel Apfelbaum, 2015/06/11
- Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses.,
Kevin O'Connor <=
- Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses., Marcel Apfelbaum, 2015/06/11
- Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses., Laszlo Ersek, 2015/06/11
- Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses., Kevin O'Connor, 2015/06/11
- Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses., Marcel Apfelbaum, 2015/06/11
- Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses., Laszlo Ersek, 2015/06/11
- Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses., Kevin O'Connor, 2015/06/11
- Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses., Laszlo Ersek, 2015/06/12
- Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses., Kevin O'Connor, 2015/06/12
- Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses., Laszlo Ersek, 2015/06/12
- Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses., Kevin O'Connor, 2015/06/12