Commit 712e6a91 authored by Huacai Chen's avatar Huacai Chen
Browse files

LoongArch: Preserve firmware configuration when desired 



If we must preserve the firmware resource assignments, claim the existing
resources rather than reassigning everything.

According to PCI Firmware Specification: if ACPI DSM#5 function returns
0, the OS must retain the resource allocation for PCI in the firmware; if
ACPI DSM#5 function returns 1, the OS can ignore the resource allocation
for PCI and reallocate it.

Signed-off-by: default avatarQihang Gao <gaoqihang@loongson.cn>
Signed-off-by: default avatarJuxin Gao <gaojuxin@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 52c22661

arch/loongarch/pci/acpi.c

+12 −2
Original line number Diff line number Diff line
@@ -194,6 +194,7 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) 
{

	struct pci_bus *bus;

	struct pci_root_info *info;

	struct pci_host_bridge *host;

	struct acpi_pci_root_ops *root_ops;

	int domain = root->segment;

	int busnum = root->secondary.start;
@@ -237,8 +238,17 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) 
			return NULL;

		}



		pci_bus_size_bridges(bus);

		pci_bus_assign_resources(bus);

		/* If we must preserve the resource configuration, claim now */

		host = pci_find_host_bridge(bus);

		if (host->preserve_config)

			pci_bus_claim_resources(bus);



		/*

		 * Assign whatever was left unassigned. If we didn't claim above,

		 * this will reassign everything.

		 */

		pci_assign_unassigned_root_bus_resources(bus);



		list_for_each_entry(child, &bus->children, node)

			pcie_bus_configure_settings(child);

	}