diff options
| author | Huacai Chen <chenhuacai@loongson.cn> | 2025-05-30 21:45:48 +0800 |
|---|---|---|
| committer | Huacai Chen <chenhuacai@loongson.cn> | 2025-05-30 21:45:48 +0800 |
| commit | 712e6a914328e9672d534fc77edd596234ec2d7f (patch) | |
| tree | 5afd7a32289d7377b73302eaa03d9bd03bc84b0f | |
| parent | 52c22661c79a7b6af7fad9f77200738fc6c51878 (diff) | |
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: Qihang Gao <gaoqihang@loongson.cn>
Signed-off-by: Juxin Gao <gaojuxin@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
| -rw-r--r-- | arch/loongarch/pci/acpi.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/arch/loongarch/pci/acpi.c b/arch/loongarch/pci/acpi.c index 1da4dc46df43..50c9016641a4 100644 --- a/arch/loongarch/pci/acpi.c +++ b/arch/loongarch/pci/acpi.c @@ -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); } |