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

Tomasz Nowicki
2015-10-21T09:58:04Z

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.

Regards,
Tomasz