Patchwork Re: [PATCH 7/7] pci bridge: implement secondary bus reset

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Submitter Michael S. Tsirkin
Date Nov. 18, 2010, 8:46 a.m.
Message ID <20101118084625.GA16832@redhat.com>
Download mbox | patch
Permalink /patch/72066/
State New
Headers show

Comments

Michael S. Tsirkin - Nov. 18, 2010, 8:46 a.m.
On Thu, Nov 18, 2010 at 04:29:10PM +0900, Isaku Yamahata wrote:
> 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 <yamahata@valinux.co.jp>
> > > Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
> > > ---
> > >  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);

Ouch, that's wrong, isn't it?
Bits 15:12 are reserved, readonly, 0.

I think we need the following (untested).
Comments?

pci: fix bridge control bit wmask

Bits 12 to 15 in bridge control register are reserver and must be
read-only zero, curent mask is 0xffff which makes them writeable. Fix
this up by using symbolic bit names for writeable bits instead of a
hardcoded constant.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

--

Patch

diff --git a/hw/pci.c b/hw/pci.c
index 00ec8ea..7d6d5ad 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -588,7 +588,17 @@  static void pci_init_wmask_bridge(PCIDevice *d)
     /* PCI_PREF_BASE_UPPER32 and PCI_PREF_LIMIT_UPPER32 */
     memset(d->wmask + PCI_PREF_BASE_UPPER32, 0xff, 8);
 
-    pci_set_word(d->wmask + PCI_BRIDGE_CONTROL, 0xffff);
+/* TODO: add this define to pci_regs.h in linux and then in qemu. */
+#define  PCI_BRIDGE_CTL_VGA_16BIT 0x10	/* VGA 16-bit decode */
+    pci_set_word(d->wmask + PCI_BRIDGE_CONTROL,
+                 PCI_BRIDGE_CTL_PARITY |
+                 PCI_BRIDGE_CTL_SERR |
+                 PCI_BRIDGE_CTL_ISA |
+                 PCI_BRIDGE_CTL_VGA |
+                 PCI_BRIDGE_CTL_VGA_16BIT |
+                 PCI_BRIDGE_CTL_MASTER_ABORT |
+                 PCI_BRIDGE_CTL_BUS_RESET |
+                 PCI_BRIDGE_CTL_FAST_BACK);
 }
 
 static int pci_init_multifunction(PCIBus *bus, PCIDevice *dev)