Re: [Patch v7 4/7] PCI/ACPI: Add interface acpi_pci_root_create()

Liviu Dudau
2015-10-21T11:02:07Z

On Wed, Oct 21, 2015 at 11:57:53AM +0200, Tomasz Nowicki wrote:
> On 14.10.2015 08:29, Jiang Liu wrote:
> >Introduce common interface acpi_pci_root_create() and related data
> >structures to create PCI root bus for ACPI PCI host bridges. It will
> >be used to kill duplicated arch specific code for IA64 and x86. It may
> >also help ARM64 in future.
> >
> >Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> >Tested-by: Tony Luck <tony.luck@intel.com>
> >Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
> >Signed-off-by: Liu Jiang <jiang.liu@linux.intel.com>
> >---
> > drivers/acpi/pci_root.c | 204 ++++++++++++++++++++++++++++++++++++++++++++++
> > include/linux/pci-acpi.h | 24 ++++++
> > 2 files changed, 228 insertions(+)
> >
>
> [...]
>
> >+
> >+struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
> >+ struct acpi_pci_root_ops *ops,
> >+ struct acpi_pci_root_info *info,
> >+ void *sysdata)
> >+{
> >+ int ret, busnum = root->secondary.start;
> >+ struct acpi_device *device = root->device;
> >+ int node = acpi_get_node(device->handle);
> >+ struct pci_bus *bus;
> >+
> >+ info->root = root;
> >+ info->bridge = device;
> >+ info->ops = ops;
> >+ INIT_LIST_HEAD(&info->resources);
> >+ snprintf(info->name, sizeof(info->name), "PCI Bus %04x:%02x",
> >+ root->segment, busnum);
> >+
> >+ if (ops->init_info && ops->init_info(info))
> >+ goto out_release_info;
> >+ if (ops->prepare_resources)
> >+ ret = ops->prepare_resources(info);
> >+ else
> >+ ret = acpi_pci_probe_root_resources(info);
> >+ if (ret < 0)
> >+ goto out_release_info;
> >+
> >+ pci_acpi_root_add_resources(info);
> >+ pci_add_resource(&info->resources, &root->secondary);
> >+ bus = pci_create_root_bus(NULL, busnum, ops->pci_ops,
> >+ sysdata, &info->resources);
>
> Thank a lot for this cleanup!!
>
> I recall you already considered passing segment (domain nr) to
> pci_create_root_bus, right? Can you please remind me why we gave up on this?
>
> I am asking because currently I can not find the way to retrieve domain
> number from pci_bus_assign_domain_nr (for those platforms which choose
> PCI_DOMAINS_GENERIC and want to use segment nr from MCFG table) which is the
> part of pci_create_root_bus.

Not sure I fully understand your question, but pci_bus_assign_domain_nr() will
put the assigned domain number in bus->domain_nr if you chose PCI_DOMAINS_GENERIC.
Do you want to override that value with the segment nr from MCFG?

Best regards,
Liviu

>
> Regards,
> Tomasz
>

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