PCI_EXP_RTCTL_CRSSVE);
}
+static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus,
+ unsigned int available_buses);
+
/*
+ * pci_scan_bridge_extend() - Scan buses behind a bridge
+ * @bus: Parent bus the bridge is on
+ * @dev: Bridge itself
+ * @max: Starting subordinate number of buses behind this bridge
+ * @available_buses: Total number of buses available for this bridge and
+ * the devices below. After the minimal bus space has
+ * been allocated the remaining buses will be
+ * distributed equally between hotplug-capable bridges.
+ * @pass: Either %0 (scan already configured bridges) or %1 (scan bridges
+ * that need to be reconfigured.
+ *
* If it's a bridge, configure it and scan the bus behind it.
* For CardBus bridges, we don't scan behind as the devices will
* be handled by the bridge driver itself.
* them, we proceed to assigning numbers to the remaining buses in
* order to avoid overlaps between old and new bus numbers.
*/
-int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
+static int pci_scan_bridge_extend(struct pci_bus *bus, struct pci_dev *dev,
+ int max, unsigned int available_buses,
+ int pass)
{
struct pci_bus *child;
int is_cardbus = (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS);
bus->busn_res.end);
}
max++;
+ if (available_buses)
+ available_buses--;
+
buses = (buses & 0xff000000)
| ((unsigned int)(child->primary) << 0)
| ((unsigned int)(child->busn_res.start) << 8)
if (!is_cardbus) {
child->bridge_ctl = bctl;
- max = pci_scan_child_bus(child);
+ max = pci_scan_child_bus_extend(child, available_buses);
} else {
/*
* For CardBus bridges, we leave 4 bus numbers
return max;
}
+
+/*
+ * pci_scan_bridge() - Scan buses behind a bridge
+ * @bus: Parent bus the bridge is on
+ * @dev: Bridge itself
+ * @max: Starting subordinate number of buses behind this bridge
+ * @pass: Either %0 (scan already configured bridges) or %1 (scan bridges
+ * that need to be reconfigured.
+ *
+ * If it's a bridge, configure it and scan the bus behind it.
+ * For CardBus bridges, we don't scan behind as the devices will
+ * be handled by the bridge driver itself.
+ *
+ * We need to process bridges in two passes -- first we scan those
+ * already configured by the BIOS and after we are done with all of
+ * them, we proceed to assigning numbers to the remaining buses in
+ * order to avoid overlaps between old and new bus numbers.
+ */
+int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
+{
+ return pci_scan_bridge_extend(bus, dev, max, 0, pass);
+}
EXPORT_SYMBOL(pci_scan_bridge);
/*
/* nothing to do, expected to be removed in the future */
}
-unsigned int pci_scan_child_bus(struct pci_bus *bus)
+/**
+ * pci_scan_child_bus_extend() - Scan devices below a bus
+ * @bus: Bus to scan for devices
+ * @available_buses: Total number of buses available (%0 does not try to
+ * extend beyond the minimal)
+ *
+ * Scans devices below @bus including subordinate buses. Returns new
+ * subordinate number including all the found devices. Passing
+ * @available_buses causes the remaining bus space to be distributed
+ * equally between hotplug-capable bridges to allow future extension of the
+ * hierarchy.
+ */
+static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus,
+ unsigned int available_buses)
{
- unsigned int devfn, max = bus->busn_res.start;
+ unsigned int used_buses, normal_bridges = 0, hotplug_bridges = 0;
+ unsigned int start = bus->busn_res.start;
+ unsigned int devfn, cmax, max = start;
struct pci_dev *dev;
dev_dbg(&bus->dev, "scanning bus\n");
pci_scan_slot(bus, devfn);
/* Reserve buses for SR-IOV capability. */
- max += pci_iov_bus_range(bus);
+ used_buses = pci_iov_bus_range(bus);
+ max += used_buses;
/*
* After performing arch-dependent fixup of the bus, look behind
bus->is_added = 1;
}
+ /*
+ * Calculate how many hotplug bridges and normal bridges there
+ * are on this bus. We will distribute the additional available
+ * buses between hotplug bridges.
+ */
+ for_each_pci_bridge(dev, bus) {
+ if (dev->is_hotplug_bridge)
+ hotplug_bridges++;
+ else
+ normal_bridges++;
+ }
+
/*
* Scan bridges that are already configured. We don't touch them
* unless they are misconfigured (which will be done in the second
* scan below).
*/
- for_each_pci_bridge(dev, bus)
- max = pci_scan_bridge(bus, dev, max, 0);
+ for_each_pci_bridge(dev, bus) {
+ cmax = max;
+ max = pci_scan_bridge_extend(bus, dev, max, 0, 0);
+ used_buses += cmax - max;
+ }
/* Scan bridges that need to be reconfigured */
- for_each_pci_bridge(dev, bus)
- max = pci_scan_bridge(bus, dev, max, 1);
+ for_each_pci_bridge(dev, bus) {
+ unsigned int buses = 0;
+
+ if (!hotplug_bridges && normal_bridges == 1) {
+ /*
+ * There is only one bridge on the bus (upstream
+ * port) so it gets all available buses which it
+ * can then distribute to the possible hotplug
+ * bridges below.
+ */
+ buses = available_buses;
+ } else if (dev->is_hotplug_bridge) {
+ /*
+ * Distribute the extra buses between hotplug
+ * bridges if any.
+ */
+ buses = available_buses / hotplug_bridges;
+ buses = min(buses, available_buses - used_buses);
+ }
+
+ cmax = max;
+ max = pci_scan_bridge_extend(bus, dev, cmax, buses, 1);
+ used_buses += max - cmax;
+ }
/*
* Make sure a hotplug bridge has at least the minimum requested
- * number of buses.
+ * number of buses but allow it to grow up to the maximum available
+ * bus number of there is room.
*/
- if (bus->self && bus->self->is_hotplug_bridge && pci_hotplug_bus_size) {
- if (max - bus->busn_res.start < pci_hotplug_bus_size - 1)
- max = bus->busn_res.start + pci_hotplug_bus_size - 1;
-
- /* Do not allocate more buses than we have room left */
- if (max > bus->busn_res.end)
- max = bus->busn_res.end;
+ if (bus->self && bus->self->is_hotplug_bridge) {
+ used_buses = max_t(unsigned int, available_buses,
+ pci_hotplug_bus_size - 1);
+ if (max - start < used_buses) {
+ max = start + used_buses;
+
+ /* Do not allocate more buses than we have room left */
+ if (max > bus->busn_res.end)
+ max = bus->busn_res.end;
+
+ dev_dbg(&bus->dev, "%pR extended by %#02x\n",
+ &bus->busn_res, max - start);
+ }
}
/*
dev_dbg(&bus->dev, "bus scan returning with max=%02x\n", max);
return max;
}
+
+/**
+ * pci_scan_child_bus() - Scan devices below a bus
+ * @bus: Bus to scan for devices
+ *
+ * Scans devices below @bus including subordinate buses. Returns new
+ * subordinate number including all the found devices.
+ */
+unsigned int pci_scan_child_bus(struct pci_bus *bus)
+{
+ return pci_scan_child_bus_extend(bus, 0);
+}
EXPORT_SYMBOL_GPL(pci_scan_child_bus);
/**
{
struct pci_bus *parent = dev->bus;
int busnr, start = parent->busn_res.start;
+ unsigned int available_buses = 0;
int end = parent->busn_res.end;
for (busnr = start; busnr <= end; busnr++) {
/* Scan bridges that are already configured */
busnr = pci_scan_bridge(parent, dev, busnr, 0);
+ /*
+ * Distribute the available bus numbers between hotplug-capable
+ * bridges to make extending the chain later possible.
+ */
+ available_buses = end - busnr;
+
/* Scan bridges that need to be reconfigured */
- pci_scan_bridge(parent, dev, busnr, 1);
+ pci_scan_bridge_extend(parent, dev, busnr, available_buses, 1);
if (!dev->subordinate)
return -1;
projects / users / jedix / linux-maple.git / commitdiff