[SLOF] [PATCH slof] pci: Put non-prefetchable 64bit BARs into 32bit MMIO window

[Alexey Kardashevskiy]

On Wed, 26 Apr 2017 15:23:40 +0200
Thomas Huth <thuth at redhat.com> wrote:

> On 24.04.2017 05:01, Alexey Kardashevskiy wrote:
> > At the moment 64bit non-prefetchable BARs of devices behind PCI p2p
> > bridge go to a 64bit prefetchable windows which is not correct and
> > causes linux guests to fail to ioremap() such resources.
> > 
> > This moves 64bit non-prefetchable BARs 32bit non-prefetchable
> > window.
> > 
> > Note that this does not make distinction between P2P and PHB so
> > from now on XHCI BARs will be allocated from 32bit MMIO space.
> > However since most 64bit-MMIO-capable devices have prefetchable
> > BARs, and XHCI BAR is just 4K (so it is unlikely to cause any space
> > problems), this should not affect usual behavior.
> > 
> > Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>
> > ---
> > 
> > This fixes QEMU's XHCI when it is put on a P2P PCI bridge.
> > 
> > There is a little naming confusion as it may look like the patch
> > is changing assignment for all 64bit BAR but it does not as:
> > - "mmio" is used for non-prefetchable memory,
> > - "mem" is used for prefetchable memory.
> > ---
> >  slof/fs/pci-properties.fs | 6 +-----
> >  1 file changed, 1 insertion(+), 5 deletions(-)
> > 
> > diff --git a/slof/fs/pci-properties.fs b/slof/fs/pci-properties.fs
> > index e6fd843..8594e5d 100644
> > --- a/slof/fs/pci-properties.fs
> > +++ b/slof/fs/pci-properties.fs
> > @@ -166,11 +166,7 @@
> >  \ Setup a non-prefetchable 64bit BAR and return its size
> >  : assign-mmio64-bar ( bar-addr -- 8 )
> >          dup pci-bar-size-mem64          \ fetch size
> > -        pci-next-mem64 @ 0 = IF          \ Check if we have 64-bit
> > memory range
> > -	    pci-next-mmio
> > -	ELSE
> > -	    pci-next-mem64              \ for board-qemu we will
> > use same range
> > -	THEN
> > +        pci-next-mmio
> >          assign-bar-value64              \ and set it all
> >  ;  
> 
> I'm sorry, but this is now causing trouble with the USB keyboard in
> *SLOF* instead. If I start QEMU now like this:
> 
> qemu-system-ppc64 -nodefaults -serial mon:stdio \
>   -device pci-bridge,bus=pci.0,id=bridge1,chassis_nr=1 \
>   -device nec-usb-xhci,id=xhci1,bus=bridge1,addr=0x3 -vga std \
>   -device usb-kbd,bus=xhci1.0 -bios boot_rom.bin
> 
> then SLOF complains: "usb-xhci: failed to initialize XHCI controller"
> and the keyboard is not working at the SLOF prompt anymore.
> 
> Any idea why this is happening now?


XHCI's usb_hcd_dev::base == 0xc0000000 which is a bus address while it
is supposed to be a mapped address, i.e. 800000020000000.

It used to work before the patch as pci address is the same as mapped
address - 210000000000 - and I am not sure if this is not an accident,
could be QEMU's PCI MMIO windows/spacing rework David did some time ago.

I am trying to figure out now where usb_hcd_dev::base is set in SLOF,
it is tricky :-/


> 
>  Thomas
> 



--
Alexey