ARM64/PCI: ACPI NUMA node set-up

This patch series is v3 of a previous posting:

v2 -> v3

- Dropped generic approach
# It was not consistent between ACPI and DT and not reusable on x86/IA64
- Trimmed the series to one patch ARM64 specific, three-line patch fixes the issue
- Rebased against v4.12-rc2
- Dropped RFC/RFT tag

v2: https://lkml.org/lkml/2017/5/15/433

v1 -> v2:

- Added missing call to acpi_pci_bus_find_numa_node()
- Rebased against v4.12-rc1

v1: https://lkml.org/lkml/2017/4/26/211

--- Original Cover Letter --

On the ARM64 architecture, the arch specific PCI pcibus_to_node() callback can be triggered on struct pci_bus.sysdata structures that carry host bridge specific data through different structures layout (ie sysdata pointer points at different structs for different host bridges), therefore it is not possible to have a unified pcibus_to_node() implementation.

Given that the device NUMA node is a property of the struct pci_bus (and its associated struct device), move the struct pci_bus node assignment to generic PCI code, where according to the platform firmware the NUMA node for the device backing the struct pci_bus is retrieved and propagated through the PCI bus hierarchy.

Lorenzo Pieralisi (1):
ARM64/PCI: Set root bus NUMA node on ACPI systems

 arch/arm64/kernel/pci.c | 3 +++
 1 file changed, 3 insertions(+)

2.10.0

PCI core requires the NUMA node for the struct pci_host_bridge.dev to be set by using the pcibus_to_node(struct pci_bus*) API, that on ARM64 systems relies on the struct pci_host_bridge->bus.dev NUMA node.

The struct pci_host_bridge.dev NUMA node is then propagated through the PCI device hierarchy as PCI devices (and bridges) are enumerated under it.

Therefore, in order to set-up the PCI NUMA hierarchy appropriately, the struct pci_host_bridge->bus.dev NUMA node must be set before core code calls pcibus_to_node(struct pci_bus*) on it so that PCI core can retrieve the NUMA node for the struct pci_host_bridge.dev device and can propagate it through the PCI bus tree.

On ARM64 ACPI based systems the struct pci_host_bridge->bus.dev NUMA node can be set-up in pcibios_root_bridge_prepare() by parsing the root bridge ACPI device firmware binding.

Add code to the pcibios_root_bridge_prepare() that, when booting with ACPI, parse the root bridge ACPI device companion NUMA binding and set the corresponding struct pci_host_bridge->bus.dev NUMA node appropriately.

---
 arch/arm64/kernel/pci.c | 3 +++
 1 file changed, 3 insertions(+)

index 4f0e3eb..1082834 100644
@@ -108,7 +108,10 @@ int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
 	if (!acpi_disabled) {
 		struct pci_config_window *cfg = bridge->bus->sysdata;
 		struct acpi_device *adev = to_acpi_device(cfg->parent);
+		struct device *bus_dev = &bridge->bus->dev;
+
 		ACPI_COMPANION_SET(&bridge->dev, adev);
+		set_dev_node(bus_dev, acpi_get_node(acpi_device_handle(adev)));
 	}
 
 	return 0;

2.10.0

Looks good.

Thanks,

-Robert

Thanks, I'll queue this with Robert's tags.

Will