[Qemu-devel] [PATCHv2-RFC 2/2] pci: add standard bridge device

["Michael S. Tsirkin" <mst@redhat.com>]

This adds support for a standard pci to pci bridge,
enabling support for more than 32 PCI devices in the system.
Device hotplug is supported by means of SHPC controller.
For guests with an SHPC driver, this allows robust hotplug
and even hotplug of nested bridges, up to 31 devices
per bridge.

TODO:
- chassis capability support
- migration support
- remove dependency on pci_internals.h

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 Makefile.objs       |    2 +-
 hw/pci_bridge_dev.c |  136 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 137 insertions(+), 1 deletions(-)
 create mode 100644 hw/pci_bridge_dev.c

diff --git a/Makefile.objs b/Makefile.objs
index 4546477..e89112c 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -193,7 +193,7 @@ hw-obj-$(CONFIG_VIRTIO) += virtio-console.o
 hw-obj-y += usb-libhw.o
 hw-obj-$(CONFIG_VIRTIO_PCI) += virtio-pci.o
 hw-obj-y += fw_cfg.o
-hw-obj-$(CONFIG_PCI) += pci.o pci_bridge.o
+hw-obj-$(CONFIG_PCI) += pci.o pci_bridge.o pci_bridge_dev.o
 hw-obj-$(CONFIG_PCI) += msix.o msi.o
 hw-obj-$(CONFIG_PCI) += shpc.o
 hw-obj-$(CONFIG_PCI) += pci_host.o pcie_host.o
diff --git a/hw/pci_bridge_dev.c b/hw/pci_bridge_dev.c
new file mode 100644
index 0000000..f48cd2d
--- /dev/null
+++ b/hw/pci_bridge_dev.c
@@ -0,0 +1,136 @@
+/*
+ * Standard PCI Bridge Device
+ *
+ * Copyright (c) 2011 Red Hat Inc. Author: Michael S. Tsirkin <mst@redhat.com>
+ *
+ * http://www.pcisig.com/specifications/conventional/pci_to_pci_bridge_architecture/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "pci_bridge.h"
+#include "pci_ids.h"
+#include "shpc.h"
+#include "memory.h"
+#include "pci_internals.h"
+
+#define REDHAT_PCI_VENDOR_ID 0x1b36
+#define PCI_BRIDGE_DEV_VENDOR_ID REDHAT_PCI_VENDOR_ID
+#define PCI_BRIDGE_DEV_DEVICE_ID 0x1
+
+struct PCIBridgeDev {
+    PCIBridge bridge;
+    MemoryRegion bar;
+};
+typedef struct PCIBridgeDev PCIBridgeDev;
+
+/* Mapping mandated by PCI-to-PCI Bridge architecture specification,
+ * revision 1.2 */
+/* Table 9-1: Interrupt Binding for Devices Behind a Bridge */
+static int pci_bridge_dev_map_irq_fn(PCIDevice *dev, int irq_num)
+{
+    return (irq_num + PCI_SLOT(dev->devfn)) % PCI_NUM_PINS;
+}
+
+static int pci_bridge_dev_initfn(PCIDevice *dev)
+{
+    PCIBridge *br = DO_UPCAST(PCIBridge, dev, dev);
+    PCIBridgeDev *bridge_dev = DO_UPCAST(PCIBridgeDev, bridge, br);
+    int err;
+    br->map_irq = pci_bridge_dev_map_irq_fn;
+    /* If we don't specify the name, the bus will be addressed as <id>.0, where
+     * id is the parent id.  But it seems more natural to address the bus using
+     * the parent device name. */
+    if (dev->qdev.id && *dev->qdev.id) {
+        br->bus_name = dev->qdev.id;
+    }
+    err = pci_bridge_initfn(dev);
+    if (err) {
+        goto bridge_error;
+    }
+    memory_region_init(&bridge_dev->bar, "shpc-bar", shpc_bar_size(dev));
+    err = shpc_init(dev, &br->sec_bus, &bridge_dev->bar, 0);
+    if (err) {
+        goto error;
+    }
+    /* TODO: spec recommends using 64 bit prefetcheable BAR.
+     * Check whether that works well. */
+    pci_register_bar(dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &bridge_dev->bar);
+    dev->config[PCI_INTERRUPT_PIN] = 0x1;
+    return 0;
+error:
+    memory_region_destroy(&bridge_dev->bar);
+bridge_error:
+    return err;
+}
+
+static int pci_bridge_dev_exitfn(PCIDevice *dev)
+{
+    PCIBridge *br = DO_UPCAST(PCIBridge, dev, dev);
+    PCIBridgeDev *bridge_dev = DO_UPCAST(PCIBridgeDev, bridge, br);
+    int ret;
+    shpc_cleanup(dev);
+    memory_region_destroy(&bridge_dev->bar);
+    ret = pci_bridge_exitfn(dev);
+    assert(!ret);
+    return 0;
+}
+
+static void pci_bridge_dev_write_config(PCIDevice *d,
+                                        uint32_t address, uint32_t val, int len)
+{
+    pci_bridge_write_config(d, address, val, len);
+    shpc_cap_write_config(d, address, val, len);
+}
+
+static void qdev_pci_bridge_dev_reset(DeviceState *qdev)
+{
+    PCIDevice *dev = DO_UPCAST(PCIDevice, qdev, qdev);
+    pci_bridge_reset(qdev);
+    shpc_reset(dev);
+}
+
+static void pci_bridge_dev_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+    k->init = pci_bridge_dev_initfn;
+    k->exit = pci_bridge_dev_exitfn;
+    k->config_write = pci_bridge_dev_write_config;
+    k->vendor_id = PCI_BRIDGE_DEV_VENDOR_ID;
+    k->device_id = PCI_BRIDGE_DEV_DEVICE_ID;
+    k->class_id = PCI_CLASS_BRIDGE_PCI;
+    k->is_bridge = 1,
+    dc->desc = "Standard PCI Bridge";
+    dc->reset = qdev_pci_bridge_dev_reset;
+    /*
+     * TODO: migration.
+     * dc->vmsd = 
+     * dc->props = 
+     */
+}
+
+static TypeInfo pci_bridge_dev_info = {
+    .name = "pci-bridge",
+    .parent        = TYPE_PCI_DEVICE,
+    .instance_size = sizeof(PCIBridgeDev),
+    .class_init = pci_bridge_dev_class_init,
+};
+
+static void pci_bridge_dev_register(void)
+{
+    type_register_static(&pci_bridge_dev_info);
+}
+
+device_init(pci_bridge_dev_register);
-- 
1.7.9.111.gf3fb0