Commit 53762ba8 authored Jan 04, 2017 by Zhou Wang Committed by Bjorn Helgaas Jan 12, 2017

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>

parent 977509f7

drivers/acpi/pci_mcfg.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -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;
		}