diff options
| -rw-r--r-- | drivers/pci/probe.c | 156 |
1 files changed, 138 insertions, 18 deletions
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 1f82f49c0bb3..14e0ea1ff38b 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -959,7 +959,21 @@ static void pci_enable_crs(struct pci_dev *pdev) 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. @@ -969,7 +983,9 @@ static void pci_enable_crs(struct pci_dev *pdev) * 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); @@ -1080,6 +1096,9 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass) 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) @@ -1101,7 +1120,7 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass) 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 @@ -1169,6 +1188,28 @@ out: 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); /* @@ -2397,9 +2438,24 @@ void __weak pcibios_fixup_bus(struct pci_bus *bus) /* 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"); @@ -2409,7 +2465,8 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus) 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 @@ -2422,28 +2479,72 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus) } /* + * 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); + } } /* @@ -2456,6 +2557,18 @@ unsigned int pci_scan_child_bus(struct pci_bus *bus) 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); /** @@ -2753,6 +2866,7 @@ int pci_hp_add_bridge(struct pci_dev *dev) { 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++) { @@ -2767,8 +2881,14 @@ int pci_hp_add_bridge(struct pci_dev *dev) /* 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; |