From 2fe2abf896c1e7a0ee65faaf3ef0ce654848abbd Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Tue, 23 Feb 2010 10:24:36 -0700 Subject: PCI: augment bus resource table with a list Previously we used a table of size PCI_BUS_NUM_RESOURCES (16) for resources forwarded to a bus by its upstream bridge. We've increased this size several times when the table overflowed. But there's no good limit on the number of resources because host bridges and subtractive decode bridges can forward any number of ranges to their secondary buses. This patch reduces the table to only PCI_BRIDGE_RESOURCE_NUM (4) entries, which corresponds to the number of windows a PCI-to-PCI (3) or CardBus (4) bridge can positively decode. Any additional resources, e.g., PCI host bridge windows or subtractively-decoded regions, are kept in a list. I'd prefer a single list rather than this split table/list approach, but that requires simultaneous changes to every architecture. This approach only requires immediate changes where we set up (a) host bridges with more than four windows and (b) subtractive-decode P2P bridges, and we can incrementally change other architectures to use the list. Signed-off-by: Bjorn Helgaas Signed-off-by: Jesse Barnes --- drivers/pci/bus.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) (limited to 'drivers/pci/bus.c') diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c index e75d219fd107..712250f5874a 100644 --- a/drivers/pci/bus.c +++ b/drivers/pci/bus.c @@ -17,6 +17,52 @@ #include "pci.h" +void pci_bus_add_resource(struct pci_bus *bus, struct resource *res, + unsigned int flags) +{ + struct pci_bus_resource *bus_res; + + bus_res = kzalloc(sizeof(struct pci_bus_resource), GFP_KERNEL); + if (!bus_res) { + dev_err(&bus->dev, "can't add %pR resource\n", res); + return; + } + + bus_res->res = res; + bus_res->flags = flags; + list_add_tail(&bus_res->list, &bus->resources); +} + +struct resource *pci_bus_resource_n(const struct pci_bus *bus, int n) +{ + struct pci_bus_resource *bus_res; + + if (n < PCI_BRIDGE_RESOURCE_NUM) + return bus->resource[n]; + + n -= PCI_BRIDGE_RESOURCE_NUM; + list_for_each_entry(bus_res, &bus->resources, list) { + if (n-- == 0) + return bus_res->res; + } + return NULL; +} +EXPORT_SYMBOL_GPL(pci_bus_resource_n); + +void pci_bus_remove_resources(struct pci_bus *bus) +{ + struct pci_bus_resource *bus_res, *tmp; + int i; + + for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++) + bus->resource[i] = 0; + + list_for_each_entry_safe(bus_res, tmp, &bus->resources, list) { + list_del(&bus_res->list); + kfree(bus_res); + } +} + /** * pci_bus_alloc_resource - allocate a resource from a parent bus * @bus: PCI bus -- cgit v1.2.3