Re: [Qemu-devel] [PATCH v3 17/26] Add i21154 bridge chip.

[Jason Baron <jbaron@redhat.com>]

On Mon, Oct 22, 2012 at 04:03:05PM +0200, Michael S. Tsirkin wrote:
> On Fri, Oct 19, 2012 at 04:43:37PM -0400, Jason Baron wrote:
> > From: Jason Baron <jbaron@redhat.com>
> > 
> > This adds support for the DECchip 21154 PCI bridge.
> > 
> > Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
> > Signed-off-by: Jason Baron <jbaron@redhat.com>
> > ---
> >  hw/Makefile.objs |    2 +-
> >  hw/i21154.c      |  113 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  hw/i21154.h      |    9 ++++
> >  3 files changed, 123 insertions(+), 1 deletions(-)
> >  create mode 100644 hw/i21154.c
> >  create mode 100644 hw/i21154.h
> > 
> > diff --git a/hw/Makefile.objs b/hw/Makefile.objs
> > index ef444d8..eb18a55 100644
> > --- a/hw/Makefile.objs
> > +++ b/hw/Makefile.objs
> > @@ -9,7 +9,7 @@ common-obj-$(CONFIG_PCI) += shpc.o
> >  common-obj-$(CONFIG_PCI) += slotid_cap.o
> >  common-obj-$(CONFIG_PCI) += pci_host.o pcie_host.o
> >  common-obj-$(CONFIG_PCI) += ioh3420.o xio3130_upstream.o xio3130_downstream.o
> > -common-obj-$(CONFIG_PCI) += i82801b11.o
> > +common-obj-$(CONFIG_PCI) += i82801b11.o i21154.o
> >  common-obj-y += watchdog.o
> >  common-obj-$(CONFIG_ISA_MMIO) += isa_mmio.o
> >  common-obj-$(CONFIG_ECC) += ecc.o
> > diff --git a/hw/i21154.c b/hw/i21154.c
> > new file mode 100644
> > index 0000000..93faa59
> > --- /dev/null
> > +++ b/hw/i21154.c
> > @@ -0,0 +1,113 @@
> > +/*
> > + * Copyright (c) 2006 Fabrice Bellard
> > + *
> > + * Permission is hereby granted, free of charge, to any person obtaining a copy
> > + * of this software and associated documentation files (the "Software"), to deal
> > + * in the Software without restriction, including without limitation the rights
> > + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> > + * copies of the Software, and to permit persons to whom the Software is
> > + * furnished to do so, subject to the following conditions:
> > + *
> > + * The above copyright notice and this permission notice shall be included in
> > + * all copies or substantial portions of the Software.
> > + *
> > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> > + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
> > + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> > + * THE SOFTWARE.
> > + */
> > +/*
> > + * QEMU i21154 PCI Bridge Emulation
> > + *
> > + *  Copyright (c) 2009, 2010, 2011
> > + *                Isaku Yamahata <yamahata at valinux co jp>
> > + *                VA Linux Systems Japan K.K.
> > + *  Copyright (C) 2012 Jason Baron <jbaron@redhat.com>
> > + *
> > + * This library is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU Lesser General Public
> > + * License as published by the Free Software Foundation; either
> > + * version 2 of the License, or (at your option) any later version.
> > + *
> > + * This library is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > + * Lesser General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU Lesser General Public
> > + * License along with this library; if not, see <http://www.gnu.org/licenses/>
> > + */
> > +
> > +#include "i21154.h"
> > +#include "pci_ids.h"
> > +#include "pci.h"
> > +#include "pci_bridge.h"
> > +#include "pci_internals.h"
> > +
> > +/* i21154 pci bridge*/
> > +
> > +typedef struct I21154Bridge {
> > +    PCIBridge br;
> > +} I21154Bridge;
> > +
> > +static int i21154_bridge_initfn(PCIDevice *d)
> > +{
> > +    int rc;
> > +
> > +    rc = pci_bridge_initfn(d);
> > +    if (rc < 0) {
> > +        return rc;
> > +    }
> > +
> > +    return 0;
> > +}
> > +
> > +#define I21154_REV            0x05
> > +#define I21154_PI             0x00
> 
> _PI seems unused
> 

I21154_PI was used in Yamahata's original patch, for the
'prog_interface' field. I didn't find it in my conversion to QOM.

However, I should have used:

pci_config_set_prog_interface(uint8_t *pci_config, uint8_t val)

Anyways, we can drop this patch for the 'hw/dec_pci.c', and we can set
it there.

> > +
> > +static void i21154_bridge_class_init(ObjectClass *klass, void *data)
> > +{
> > +    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
> > +
> > +    k->is_bridge = 1;
> > +    k->vendor_id = PCI_VENDOR_ID_DEC;
> > +    k->device_id = PCI_DEVICE_ID_DEC_21154;
> > +    k->revision = I21154_REV;
> > +    k->init = i21154_bridge_initfn;
> > +}
> > +
> > +static const TypeInfo i21154_bridge_info = {
> > +    .name          = "i21154-bridge",
> > +    .parent        = TYPE_PCI_DEVICE,
> > +    .instance_size = sizeof(I21154Bridge),
> > +    .class_init    = i21154_bridge_class_init,
> > +};
> > +
> > +PCIBridge *i21154_init(PCIBus *bus, int devfn, const char *bus_name,
> > +                              bool multifunction)
> > +{
> > +    PCIDevice *d;
> > +    PCIBridge *br;
> > +    DeviceState *qdev;
> > +
> > +    d = pci_create_multifunction(bus, devfn, multifunction, "i21154-bridge");
> > +    if (!d) {
> > +        return NULL;
> > +    }
> > +    br = DO_UPCAST(PCIBridge, dev, d);
> > +    qdev = &br->dev.qdev;
> > +
> > +    pci_bridge_map_irq(br, bus_name, pci_swizzle_map_irq_fn);
> > +    qdev_init_nofail(qdev);
> > +
> > +    return br;
> > +}
> > +
> > +static void i21154_register(void)
> > +{
> > +    type_register_static(&i21154_bridge_info);
> > +}
> > +type_init(i21154_register);
> > diff --git a/hw/i21154.h b/hw/i21154.h
> > new file mode 100644
> > index 0000000..0cf8753
> > --- /dev/null
> > +++ b/hw/i21154.h
> > @@ -0,0 +1,9 @@
> > +#ifndef QEMU_I21154_H
> > +#define QEMU_I21154_H
> > +
> > +#include "pci.h"
> > +
> > +PCIBridge *i21154_init(PCIBus *bus, int devfn, const char *bus_name,
> > +                              bool multifunction);
> > +
> > +#endif /* QEMU_I21154_H */
> 
> Looks like one can create this device through -device but if
> one does i21154_init is not called.
> Do we need i21154_init? Can we initialize the device through the
> type system in the regular way?
> 
> Same applies to other system devices.
> 

The common pattern in these '_init' functions is:

    dev = pci_create_multifunction(parent_bus, devfn, false,
                                   "bridge name foo");
    br = DO_UPCAST(PCIBridge, dev, dev);
    pci_bridge_map_irq(br, "foo bridge", map_irq);
    qdev_init_nofail(&dev->qdev);

However, when we initialize bridges through the type system, we
typically end up without a 'map_irq' function, since we haven't set
one via 'pci_bridge_map_irq'.

A quick hack fix is below (which might be ok for the short term). 

--- a/hw/pci_bridge.c
+++ b/hw/pci_bridge.c
@@ -321,6 +321,9 @@ int pci_bridge_initfn(PCIDevice *dev)
     qbus_create_inplace(&sec_bus->qbus, TYPE_PCI_BUS, &dev->qdev,
                         br->bus_name);
     sec_bus->parent_dev = dev;
+    if (!br->map_irq) {
+        br->map_irq = pci_swizzle_map_irq_fn;
+    }
     sec_bus->map_irq = br->map_irq;
     sec_bus->address_space_mem = &br->address_space_mem;
     memory_region_init(&br->address_space_mem, "pci_bridge_pci", INT64_MAX);


A more proper solution might be to introduce an abstract PCIBridgeClass,
and have all of the bridges inherit from there instead of PCIDevice and
then initialize the map_irq function there. And then have these '_init'
functions overwrite things if they want to.

Thanks,

-Jason