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@xxxxxxx>
> Signed-off-by: Zhou Wang <wangzhou1@xxxxxxxxxxxxx>
> ---
> 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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