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@@ -959,7 +959,21 @@ static void pci_enable_crs(struct pci_dev *pdev)
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PCI_EXP_RTCTL_CRSSVE);
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}
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+static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus,
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+ unsigned int available_buses);
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+
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/*
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+ * pci_scan_bridge_extend() - Scan buses behind a bridge
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+ * @bus: Parent bus the bridge is on
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+ * @dev: Bridge itself
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+ * @max: Starting subordinate number of buses behind this bridge
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+ * @available_buses: Total number of buses available for this bridge and
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+ * the devices below. After the minimal bus space has
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+ * been allocated the remaining buses will be
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+ * distributed equally between hotplug-capable bridges.
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+ * @pass: Either %0 (scan already configured bridges) or %1 (scan bridges
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+ * that need to be reconfigured.
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+ *
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* If it's a bridge, configure it and scan the bus behind it.
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* For CardBus bridges, we don't scan behind as the devices will
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* be handled by the bridge driver itself.
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@@ -969,7 +983,9 @@ static void pci_enable_crs(struct pci_dev *pdev)
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* them, we proceed to assigning numbers to the remaining buses in
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* order to avoid overlaps between old and new bus numbers.
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*/
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-int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
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+static int pci_scan_bridge_extend(struct pci_bus *bus, struct pci_dev *dev,
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+ int max, unsigned int available_buses,
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+ int pass)
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{
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struct pci_bus *child;
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int is_cardbus = (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS);
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@@ -1076,9 +1092,13 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
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child = pci_add_new_bus(bus, dev, max+1);
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if (!child)
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goto out;
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- pci_bus_insert_busn_res(child, max+1, 0xff);
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+ pci_bus_insert_busn_res(child, max+1,
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+ bus->busn_res.end);
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}
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max++;
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+ if (available_buses)
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+ available_buses--;
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+
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buses = (buses & 0xff000000)
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| ((unsigned int)(child->primary) << 0)
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| ((unsigned int)(child->busn_res.start) << 8)
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@@ -1100,7 +1120,7 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
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if (!is_cardbus) {
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child->bridge_ctl = bctl;
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- max = pci_scan_child_bus(child);
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+ max = pci_scan_child_bus_extend(child, available_buses);
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} else {
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/*
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* For CardBus bridges, we leave 4 bus numbers
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@@ -1168,6 +1188,28 @@ out:
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return max;
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}
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+
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+/*
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+ * pci_scan_bridge() - Scan buses behind a bridge
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+ * @bus: Parent bus the bridge is on
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+ * @dev: Bridge itself
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+ * @max: Starting subordinate number of buses behind this bridge
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+ * @pass: Either %0 (scan already configured bridges) or %1 (scan bridges
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+ * that need to be reconfigured.
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+ *
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+ * If it's a bridge, configure it and scan the bus behind it.
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+ * For CardBus bridges, we don't scan behind as the devices will
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+ * be handled by the bridge driver itself.
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+ *
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+ * We need to process bridges in two passes -- first we scan those
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+ * already configured by the BIOS and after we are done with all of
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+ * them, we proceed to assigning numbers to the remaining buses in
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+ * order to avoid overlaps between old and new bus numbers.
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+ */
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+int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
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+{
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+ return pci_scan_bridge_extend(bus, dev, max, 0, pass);
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+}
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EXPORT_SYMBOL(pci_scan_bridge);
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/*
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@@ -2396,9 +2438,24 @@ void __weak pcibios_fixup_bus(struct pci_bus *bus)
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/* nothing to do, expected to be removed in the future */
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}
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-unsigned int pci_scan_child_bus(struct pci_bus *bus)
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+/**
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+ * pci_scan_child_bus_extend() - Scan devices below a bus
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+ * @bus: Bus to scan for devices
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+ * @available_buses: Total number of buses available (%0 does not try to
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+ * extend beyond the minimal)
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+ *
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+ * Scans devices below @bus including subordinate buses. Returns new
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+ * subordinate number including all the found devices. Passing
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+ * @available_buses causes the remaining bus space to be distributed
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+ * equally between hotplug-capable bridges to allow future extension of the
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+ * hierarchy.
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+ */
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+static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus,
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+ unsigned int available_buses)
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{
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- unsigned int devfn, pass, max = bus->busn_res.start;
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+ unsigned int used_buses, normal_bridges = 0, hotplug_bridges = 0;
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+ unsigned int start = bus->busn_res.start;
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+ unsigned int devfn, cmax, max = start;
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struct pci_dev *dev;
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dev_dbg(&bus->dev, "scanning bus\n");
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@@ -2408,7 +2465,8 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus)
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pci_scan_slot(bus, devfn);
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/* Reserve buses for SR-IOV capability. */
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- max += pci_iov_bus_range(bus);
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+ used_buses = pci_iov_bus_range(bus);
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+ max += used_buses;
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/*
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* After performing arch-dependent fixup of the bus, look behind
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@@ -2420,19 +2478,73 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus)
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bus->is_added = 1;
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}
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- for (pass = 0; pass < 2; pass++)
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- list_for_each_entry(dev, &bus->devices, bus_list) {
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- if (pci_is_bridge(dev))
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- max = pci_scan_bridge(bus, dev, max, pass);
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+ /*
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+ * Calculate how many hotplug bridges and normal bridges there
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+ * are on this bus. We will distribute the additional available
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+ * buses between hotplug bridges.
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+ */
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+ for_each_pci_bridge(dev, bus) {
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+ if (dev->is_hotplug_bridge)
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+ hotplug_bridges++;
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+ else
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+ normal_bridges++;
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+ }
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+
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+ /*
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+ * Scan bridges that are already configured. We don't touch them
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+ * unless they are misconfigured (which will be done in the second
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+ * scan below).
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+ */
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+ for_each_pci_bridge(dev, bus) {
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+ cmax = max;
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+ max = pci_scan_bridge_extend(bus, dev, max, 0, 0);
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+ used_buses += cmax - max;
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+ }
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+
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+ /* Scan bridges that need to be reconfigured */
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+ for_each_pci_bridge(dev, bus) {
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+ unsigned int buses = 0;
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+
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+ if (!hotplug_bridges && normal_bridges == 1) {
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+ /*
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+ * There is only one bridge on the bus (upstream
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+ * port) so it gets all available buses which it
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+ * can then distribute to the possible hotplug
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+ * bridges below.
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+ */
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+ buses = available_buses;
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+ } else if (dev->is_hotplug_bridge) {
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+ /*
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+ * Distribute the extra buses between hotplug
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+ * bridges if any.
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+ */
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+ buses = available_buses / hotplug_bridges;
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+ buses = min(buses, available_buses - used_buses);
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}
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+ cmax = max;
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+ max = pci_scan_bridge_extend(bus, dev, cmax, buses, 1);
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+ used_buses += max - cmax;
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+ }
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+
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/*
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* Make sure a hotplug bridge has at least the minimum requested
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- * number of buses.
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+ * number of buses but allow it to grow up to the maximum available
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+ * bus number of there is room.
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*/
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- if (bus->self && bus->self->is_hotplug_bridge && pci_hotplug_bus_size) {
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- if (max - bus->busn_res.start < pci_hotplug_bus_size - 1)
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- max = bus->busn_res.start + pci_hotplug_bus_size - 1;
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+ if (bus->self && bus->self->is_hotplug_bridge) {
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+ used_buses = max_t(unsigned int, available_buses,
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+ pci_hotplug_bus_size - 1);
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+ if (max - start < used_buses) {
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+ max = start + used_buses;
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+
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+ /* Do not allocate more buses than we have room left */
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+ if (max > bus->busn_res.end)
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+ max = bus->busn_res.end;
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+
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+ dev_dbg(&bus->dev, "%pR extended by %#02x\n",
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+ &bus->busn_res, max - start);
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+ }
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}
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/*
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@@ -2445,6 +2557,18 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus)
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dev_dbg(&bus->dev, "bus scan returning with max=%02x\n", max);
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return max;
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}
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+
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+/**
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+ * pci_scan_child_bus() - Scan devices below a bus
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+ * @bus: Bus to scan for devices
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+ *
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+ * Scans devices below @bus including subordinate buses. Returns new
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+ * subordinate number including all the found devices.
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+ */
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+unsigned int pci_scan_child_bus(struct pci_bus *bus)
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+{
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+ return pci_scan_child_bus_extend(bus, 0);
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+}
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EXPORT_SYMBOL_GPL(pci_scan_child_bus);
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/**
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@@ -2737,3 +2861,38 @@ void __init pci_sort_breadthfirst(void)
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{
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bus_sort_breadthfirst(&pci_bus_type, &pci_sort_bf_cmp);
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}
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+
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+int pci_hp_add_bridge(struct pci_dev *dev)
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+{
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+ struct pci_bus *parent = dev->bus;
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+ int busnr, start = parent->busn_res.start;
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+ unsigned int available_buses = 0;
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+ int end = parent->busn_res.end;
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+
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+ for (busnr = start; busnr <= end; busnr++) {
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+ if (!pci_find_bus(pci_domain_nr(parent), busnr))
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+ break;
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+ }
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+ if (busnr-- > end) {
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+ dev_err(&dev->dev, "No bus number available for hot-added bridge\n");
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+ return -1;
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+ }
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+
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+ /* Scan bridges that are already configured */
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+ busnr = pci_scan_bridge(parent, dev, busnr, 0);
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+
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+ /*
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+ * Distribute the available bus numbers between hotplug-capable
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+ * bridges to make extending the chain later possible.
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+ */
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+ available_buses = end - busnr;
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+
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+ /* Scan bridges that need to be reconfigured */
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+ pci_scan_bridge_extend(parent, dev, busnr, available_buses, 1);
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+
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+ if (!dev->subordinate)
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+ return -1;
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+
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+ return 0;
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+}
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+EXPORT_SYMBOL_GPL(pci_hp_add_bridge);
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Bjorn Helgaas