PCI/ACPI: Fix bus range comparison in pci_mcfg_lookup()

The configuration data provided by an MCFG entry, i.e., PCI segment and bus
range, may span multiple host bridges.

pci_mcfg_lookup() previously required an exact match of the host bridge
starting bus and the MCFG starting bus, which made the following
configuration fail:

  MCFG region:
    segment: 0
    bus range: 0x00-0xff

  host bridge
    segment: 0
    bus range: 0x20-0x4f

Relax the bus range check in pci_mcfg_lookup() so we can use any MCFG entry
that contains the required bus range, as we do in pci_mmconfig_lookup().

[bhelgaas: changelog]
Signed-off-by: Zhou Wang <wangzhou1@hisilicon.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Tomasz Nowicki <tn@semihalf.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
index a6a4ceaa6cc3565b547739775fcf8425d2ac1ede..2944353253ed47f80a1ef936f498e61088e6ff84 100644 (file)
--- a/drivers/acpi/pci_mcfg.c
+++ b/drivers/acpi/pci_mcfg.c
@@ -195,11 +195,10 @@ int pci_mcfg_lookup(struct acpi_pci_root *root, struct resource *cfgres,
                goto skip_lookup;
 
        /*
-        * We expect exact match, unless MCFG entry end bus covers more than
-        * specified by caller.
+        * We expect the range in bus_res in the coverage of MCFG bus range.
         */
        list_for_each_entry(e, &pci_mcfg_list, list) {
-               if (e->segment == seg && e->bus_start == bus_res->start &&
+               if (e->segment == seg && e->bus_start <= bus_res->start &&
                    e->bus_end >= bus_res->end) {
                        root->mcfg_addr = e->addr;
                }