[Qemu-devel] Re: [PATCH 7/7] pci bridge: implement secondary bus reset

[Isaku Yamahata]

On Thu, Nov 18, 2010 at 09:05:30AM +0200, Michael S. Tsirkin wrote:
> On Wed, Nov 17, 2010 at 01:50:27PM +0900, Isaku Yamahata wrote:
> > Emulates secondary bus reset when secondary bus reset bit
> > is written from 0 to 1.
> > 
> > Signed-off-by: Isaku Yamahata <address@hidden>
> > Signed-off-by: Anthony Liguori <address@hidden>
> > ---
> >  hw/pci_bridge.c |   12 +++++++++++-
> >  1 files changed, 11 insertions(+), 1 deletions(-)
> > 
> > diff --git a/hw/pci_bridge.c b/hw/pci_bridge.c
> > index 58cc2e4..618a81e 100644
> > --- a/hw/pci_bridge.c
> > +++ b/hw/pci_bridge.c
> > @@ -139,6 +139,10 @@ pcibus_t pci_bridge_get_limit(const PCIDevice *bridge, 
> > uint8_t type)
> >  void pci_bridge_write_config(PCIDevice *d,
> >                               uint32_t address, uint32_t val, int len)
> >  {
> > +    PCIBridge *s = container_of(d, PCIBridge, dev);
> > +    uint16_t bridge_control = pci_get_word(d->config + PCI_BRIDGE_CONTROL);
> > +    uint16_t bridge_control_new;
> > +
> >      pci_default_write_config(d, address, val, len);
> >  
> >      if (/* io base/limit */
> > @@ -147,9 +151,15 @@ void pci_bridge_write_config(PCIDevice *d,
> >          /* memory base/limit, prefetchable base/limit and
> >             io base/limit upper 16 */
> >          ranges_overlap(address, len, PCI_MEMORY_BASE, 20)) {
> > -        PCIBridge *s = container_of(d, PCIBridge, dev);
> >          pci_bridge_update_mappings(&s->sec_bus);
> >      }
> > +
> > +    bridge_control_new = pci_get_word(d->config + PCI_BRIDGE_CONTROL);
> > +    if (!(bridge_control & PCI_BRIDGE_CTL_BUS_RESET) &&
> > +        (bridge_control_new & PCI_BRIDGE_CTL_BUS_RESET)) {
> > +        /* 0 -> 1 */
> > +        pci_bus_reset(&s->sec_bus);
> > +    }
> >  }
> >  
> >  void pci_bridge_disable_base_limit(PCIDevice *dev)
> 
> Presumably this bit will have to be made writeable?

Yes, it's already writable.
static void pci_init_wmask_bridge(PCIDevice *d)
...
   pci_set_word(d->wmask + PCI_BRIDGE_CONTROL, 0xffff);

-- 
yamahata