Messages in this thread | | | Date | Tue, 3 Jan 2017 12:00:21 +0000 | From | Lorenzo Pieralisi <> | Subject | Re: [RFC PATCH] ACPI/PCI: Fix bus range comparation in pci_mcfg_lookup |
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On Thu, Dec 22, 2016 at 05:07:43PM +0800, Zhou Wang wrote: > Multiple PCIe host bridges may exists in one PCIe segment. So bus range for each > host bridge should be in the coverage of bus range of related PCIe segment. > > This patch will support this kind of scenario: > > MCFG: > bus range: 0x00~0xff. > segment: 0. > DSDT: > host bridge 1: > bus range: 0x00~0x1f. > segment: 0. > host bridge 2: > bus range: 0x20~0x4f. > segment: 0.
"The configuration data provided by an MCFG region (ie PCI segment and bus range) may span multiple host bridges.
Current code in pci_mcfg_lookup() carries out an exact match of host bridge bus range start value against the MCFG region(s) bus range start value which would cause configurations like the following:
MCFG region: bus range: 0x00~0xff. segment: 0.
PCI host bridges configuration (segment numbers and bus ranges): host bridge 1: bus range: 0x00~0x1f. segment: 0. host bridge 2: bus range: 0x20~0x4f. segment: 0.
to fail, in that the bus range start value for host bridge 2 does not match the bus range start value of the respective MCFG region.
Relax the bus range check in pci_mcfg_lookup() to cater for PCI configurations with multiple host bridges sharing the same MCFG region."
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Signed-off-by: Zhou Wang <wangzhou1@hisilicon.com> > --- > drivers/acpi/pci_mcfg.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c > index b5b376e..46a3e32 100644 > --- a/drivers/acpi/pci_mcfg.c > +++ b/drivers/acpi/pci_mcfg.c > @@ -40,11 +40,10 @@ phys_addr_t pci_mcfg_lookup(u16 seg, struct resource *bus_res) > struct mcfg_entry *e; > > /* > - * 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) > return e->addr; > } > -- > 1.9.1 >
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