PCI/ACPI: provide MMCONFIG address for PCI host bridges

This patch provide MMCONFIG address for PCI host bridges, which will
be used to support host bridge hotplug.  It gets MMCONFIG address
by evaluating _CBA method if available.

Reviewed-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jiang Liu <liuj97@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 61e2fefeedab..87f4c504eafb 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -162,6 +162,20 @@ acpi_status pci_acpi_remove_pm_notifier(struct acpi_device *dev)
         return remove_pm_notifier(dev, pci_acpi_wake_dev);
 }
 
+phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle)
+{
+        acpi_status status = AE_NOT_EXIST;
+        unsigned long long mcfg_addr;
+
+        if (handle)
+                status = acpi_evaluate_integer(handle, METHOD_NAME__CBA,
+                                               NULL, &mcfg_addr);
+        if (ACPI_FAILURE(status))
+                return 0;
+
+        return (phys_addr_t)mcfg_addr;
+}
+
 /*
  * _SxD returns the D-state with the highest power
  * (lowest D-state number) supported in the S-state "x".