This patch adds a basic PCI<->PCI bridge driver that utilizes the new
PCI bus class API.
Signed-off-by: Adam Belay <[email protected]>
--- a/drivers/pci/bus/pci-bridge.c 1969-12-31 19:00:00.000000000 -0500
+++ b/drivers/pci/bus/pci-bridge.c 2005-07-08 02:18:43.000000000 -0400
@@ -0,0 +1,165 @@
+/*
+ * pci-bridge.c - a generic PCI bus driver for PCI<->PCI bridges
+ *
+ */
+
+#include <linux/pci.h>
+#include <linux/init.h>
+#include <linux/module.h>
+
+static struct pci_device_id ppb_id_tbl[] = {
+ { PCI_DEVICE_CLASS(PCI_CLASS_BRIDGE_PCI << 8, 0xffff00) },
+ { 0 },
+};
+
+MODULE_DEVICE_TABLE(pci, ppb_id_tbl);
+
+/**
+ * ppb_create_bus - allocates a bus and fills in basic information
+ * @dev: the pci bridge device
+ */
+static struct pci_bus * ppb_create_bus(struct pci_dev *dev)
+{
+ int i;
+ struct pci_bus *bus = pci_alloc_bus();
+
+ if (!bus)
+ return NULL;
+
+ bus->parent = dev->bus;
+ bus->bridge = &dev->dev;
+ bus->ops = bus->parent->ops;
+ bus->sysdata = bus->parent->sysdata;
+ bus->bridge = get_device(&dev->dev);
+
+ /* Set up default resource pointers and names.. */
+ for (i = 0; i < 4; i++) {
+ bus->resource[i] = &dev->resource[PCI_BRIDGE_RESOURCES+i];
+ bus->resource[i]->name = bus->name;
+ }
+
+ return bus;
+}
+
+/**
+ * ppb_detect_bus - creates a bus and reads configuration space data
+ * @dev: the pci bridge device
+ *
+ * This function will do some verification to ensure we should drive this
+ * bridge.
+ */
+static struct pci_bus * ppb_detect_bus(struct pci_dev *dev)
+{
+ struct pci_bus *bus;
+ u32 buses;
+ u16 bctl;
+ unsigned int busnr;
+
+ pci_read_config_dword(dev, PCI_PRIMARY_BUS, &buses);
+ busnr = (buses >> 8) & 0xFF;
+
+ /*
+ * FIXME: This driver currently doesn't support bridges that haven't
+ * been configured by the BIOS.
+ */
+ if (!(buses & 0xffff00)) {
+ printk(KERN_INFO "PCI: Unable to drive bus %04x:%02x\n",
+ pci_domain_nr(dev->bus), busnr);
+ return NULL;
+ }
+
+ /*
+ * If we already got to this bus through a different bridge,
+ * ignore it. This can happen with the i450NX chipset.
+ */
+ if (pci_find_bus(pci_domain_nr(dev->bus), busnr)) {
+ printk(KERN_INFO "PCI: Bus %04x:%02x already known\n",
+ pci_domain_nr(dev->bus), busnr);
+ return NULL;
+ }
+
+ bus = ppb_create_bus(dev);
+ if (!bus)
+ return NULL;
+
+ /* Disable MasterAbortMode during probing to avoid reporting
+ * of bus errors (in some architectures)
+ */
+ pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &bctl);
+ pci_write_config_word(dev, PCI_BRIDGE_CONTROL,
+ bctl & ~PCI_BRIDGE_CTL_MASTER_ABORT);
+
+ bus->number = bus->secondary = busnr;
+ bus->primary = buses & 0xFF;
+ bus->subordinate = (buses >> 16) & 0xFF;
+ bus->bridge_ctl = bctl;
+
+ return bus;
+}
+
+/**
+ * ppb_detect_children - detects and registers child devices
+ * @bus: pci bus
+ */
+static void ppb_detect_children(struct pci_bus *bus)
+{
+ unsigned int devfn;
+
+ /* Go find them, Rover! */
+ for (devfn = 0; devfn < 0x100; devfn += 8)
+ pci_scan_slot(bus, devfn);
+
+ pcibios_fixup_bus(bus);
+ pci_bus_add_devices(bus);
+}
+
+static int ppb_probe(struct pci_dev *dev, const struct pci_device_id *id)
+{
+ int err;
+ struct pci_bus *bus;
+
+ if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE)
+ return -ENODEV;
+
+ bus = ppb_detect_bus(dev);
+ if (!bus)
+ return -ENODEV;
+
+ err = pci_add_bus(bus);
+ if (err)
+ goto out;
+
+ dev->subordinate = bus;
+ ppb_detect_children(bus);
+ return 0;
+
+out:
+ kfree(bus);
+ return err;
+}
+
+static void ppb_remove(struct pci_dev *dev)
+{
+ pci_remove_behind_bridge(dev);
+ pci_remove_bus(dev->subordinate);
+}
+
+static struct pci_driver ppb_driver = {
+ .name = "pci-bridge",
+ .id_table = ppb_id_tbl,
+ .probe = ppb_probe,
+ .remove = ppb_remove,
+};
+
+static int __init ppb_init(void)
+{
+ return pci_register_driver(&ppb_driver);
+}
+
+static void __exit ppb_exit(void)
+{
+ pci_unregister_driver(&ppb_driver);
+}
+
+module_init(ppb_init);
+module_exit(ppb_exit);
--- a/drivers/pci/bus/Makefile 2005-07-07 22:22:49.000000000 -0400
+++ b/drivers/pci/bus/Makefile 2005-07-08 02:16:39.000000000 -0400
@@ -2,4 +2,4 @@
# Makefile for the PCI device detection
#
-obj-y := bus.o config.o device.o probe.o
+obj-y := bus.o config.o device.o probe.o pci-bridge.o
-
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