[Linaro-acpi] [PATCH V1 10/11] pci, acpi: Provide generic way to assign bus domain number.
tomasz.nowicki at linaro.org
Wed Nov 4 02:04:58 PST 2015
On 03.11.2015 17:10, Lorenzo Pieralisi wrote:
> On Tue, Oct 27, 2015 at 05:38:41PM +0100, Tomasz Nowicki wrote:
>> Architectures which support PCI_DOMAINS_GENERIC (like ARM64)
>> cannot call pci_bus_assign_domain_nr along ACPI PCI host bridge
>> initialization since this function needs valid parent device reference
>> to be able to retrieve domain number (aka segment).
>> We can omit that blocker and pass down host bridge device via
>> pci_create_root_bus parameter and then be able to evaluate _SEG method
>> being in pci_bus_assign_domain_nr.
>> Note that _SEG method is optional, therefore _SEG absence means
>> that all PCI buses belong to domain 0.
>> Signed-off-by: Tomasz Nowicki <tn at semihalf.com>
>> drivers/acpi/pci_root.c | 2 +-
>> drivers/pci/pci.c | 32 +++++++++++++++++++++++++++-----
>> 2 files changed, 28 insertions(+), 6 deletions(-)
>> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
>> index 850d7bf..e682dc6 100644
>> --- a/drivers/acpi/pci_root.c
>> +++ b/drivers/acpi/pci_root.c
>> @@ -839,7 +839,7 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
>> pci_add_resource(&info->resources, &root->secondary);
>> - bus = pci_create_root_bus(NULL, busnum, ops->pci_ops,
>> + bus = pci_create_root_bus(&device->dev, busnum, ops->pci_ops,
>> sysdata, &info->resources);
> If I read x86 code correctly, they rely on the first argument to be
> NULL, I think you would break x86 by doing that, see:
> arch/x86/pci/acpi.c (pcibios_root_bridge_prepare())
> By the way, can't we move the code setting up the ACPI_COMPANION
> to core PCI code and stop relying on sysdata for that ?
Yes, that will break x86&ia64 but as you said it may be overcome with
consolidation of ACPI_COMPANION into the core code.
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