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 <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index 959e548..a2f8cdb 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -45,20 +45,6 @@
return AE_OK;
}
-static int
-bus_has_transparent_bridge(struct pci_bus *bus)
-{
- struct pci_dev *dev;
-
- list_for_each_entry(dev, &bus->devices, bus_list) {
- u16 class = dev->class >> 8;
-
- if (class == PCI_CLASS_BRIDGE_PCI && dev->transparent)
- return true;
- }
- return false;
-}
-
static void
align_resource(struct acpi_device *bridge, struct resource *res)
{
@@ -92,12 +78,8 @@
acpi_status status;
unsigned long flags;
struct resource *root;
- int max_root_bus_resources = PCI_BUS_NUM_RESOURCES;
u64 start, end;
- if (bus_has_transparent_bridge(info->bus))
- max_root_bus_resources -= 3;
-
status = resource_to_addr(acpi_res, &addr);
if (!ACPI_SUCCESS(status))
return AE_OK;
@@ -115,15 +97,6 @@
start = addr.minimum + addr.translation_offset;
end = start + addr.address_length - 1;
- if (info->res_num >= max_root_bus_resources) {
- if (pci_probe & PCI_USE__CRS)
- printk(KERN_WARNING "PCI: Failed to allocate "
- "0x%lx-0x%lx from %s for %s due to _CRS "
- "returning more than %d resource descriptors\n",
- (unsigned long) start, (unsigned long) end,
- root->name, info->name, max_root_bus_resources);
- return AE_OK;
- }
res = &info->res[info->res_num];
res->name = info->name;
@@ -143,7 +116,7 @@
dev_err(&info->bridge->dev,
"can't allocate host bridge window %pR\n", res);
} else {
- info->bus->resource[info->res_num] = res;
+ pci_bus_add_resource(info->bus, res, 0);
info->res_num++;
if (addr.translation_offset)
dev_info(&info->bridge->dev, "host bridge window %pR "
@@ -164,7 +137,9 @@
struct pci_root_info info;
size_t size;
- if (!(pci_probe & PCI_USE__CRS))
+ if (pci_probe & PCI_USE__CRS)
+ pci_bus_remove_resources(bus);
+ else
dev_info(&device->dev,
"ignoring host bridge windows from ACPI; "
"boot with \"pci=use_crs\" to use them\n");