As we now have valid PCI host bridge device reference we can introduce code that is going to find its bus domain number using ACPI _SEG method.
Note that _SEG method is optional, therefore _SEG absence means that all PCI buses belong to domain 0.
Signed-off-by: Tomasz Nowicki tn@semihalf.com Reviewed-by: Liviu Dudau Liviu.Dudau@arm.com Tested-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com --- drivers/pci/pci.c | 29 +++++++++++++++++++++++++---- 1 file changed, 25 insertions(+), 4 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 7274006..39a985b 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -25,6 +25,7 @@ #include <linux/device.h> #include <linux/pm_runtime.h> #include <linux/pci_hotplug.h> +#include <linux/acpi.h> #include <asm-generic/pci-bridge.h> #include <asm/setup.h> #include <linux/aer.h> @@ -4796,14 +4797,34 @@ void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent) * API and update the use_dt_domains value to keep track of method we * are using to assign domain numbers (use_dt_domains = 0). * + * IF ACPI, we expect non-DT method (use_dt_domains == -1) + * and call _SEG method for corresponding host bridge device. + * If _SEG method does not exist, following ACPI spec (6.5.6) + * all PCI buses belong to domain 0. + * * All other combinations imply we have a platform that is trying - * to mix domain numbers obtained from DT and pci_get_new_domain_nr(), - * which is a recipe for domain mishandling and it is prevented by - * invalidating the domain value (domain = -1) and printing a - * corresponding error. + * to mix domain numbers obtained from DT, ACPI and + * pci_get_new_domain_nr(), which is a recipe for domain mishandling and + * it is prevented by invalidating the domain value (domain = -1) and + * printing a corresponding error. */ + if (domain >= 0 && use_dt_domains) { use_dt_domains = 1; +#ifdef CONFIG_ACPI + } else if (!acpi_disabled && use_dt_domains == -1) { + struct acpi_device *acpi_dev = to_acpi_device(parent); + unsigned long long segment = 0; + acpi_status status; + + status = acpi_evaluate_integer(acpi_dev->handle, + METHOD_NAME__SEG, NULL, + &segment); + if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) + dev_err(&acpi_dev->dev, "can't evaluate _SEG\n"); + + domain = segment; +#endif } else if (domain < 0 && use_dt_domains != 1) { use_dt_domains = 0; domain = pci_get_new_domain_nr();