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>

5 files changed, 19 insertions, 0 deletions

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 7aff6312ce7c..ec54014c321c 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -505,6 +505,8 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
         strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
         device->driver_data = root;
 
+        root->mcfg_addr = acpi_pci_root_get_mcfg_addr(device->handle);
+
         /*
          * All supported architectures that use ACPI have support for
          * PCI domains, so we indicate this in _OSC support capabilities.
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".
diff --git a/include/acpi/acnames.h b/include/acpi/acnames.h
index 38f508816e4a..b177f97f53b6 100644
--- a/include/acpi/acnames.h
+++ b/include/acpi/acnames.h
@@ -62,6 +62,7 @@
 #define METHOD_NAME__AEI        "_AEI"
 #define METHOD_NAME__PRW        "_PRW"
 #define METHOD_NAME__SRS        "_SRS"
+#define METHOD_NAME__CBA        "_CBA"
 
 /* Method names - these methods must appear at the namespace root */
 
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 9e6e1c6eb60a..457974073994 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -401,6 +401,7 @@ struct acpi_pci_root {
 
         u32 osc_support_set;    /* _OSC state of support bits */
         u32 osc_control_set;    /* _OSC state of control bits */
+        phys_addr_t mcfg_addr;
 };
 
 /* helper */
diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 44623500f419..248fba2af98a 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -17,6 +17,7 @@ extern acpi_status pci_acpi_remove_bus_pm_notifier(struct acpi_device *dev);
 extern acpi_status pci_acpi_add_pm_notifier(struct acpi_device *dev,
                                              struct pci_dev *pci_dev);
 extern acpi_status pci_acpi_remove_pm_notifier(struct acpi_device *dev);
+extern phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle);
 
 static inline acpi_handle acpi_find_root_bridge_handle(struct pci_dev *pdev)
 {