1 files changed, 81 insertions, 4 deletions

diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
index f8c187a763bd..93e37f0666ab 100644
--- a/drivers/pci/hotplug/acpi_pcihp.c
+++ b/drivers/pci/hotplug/acpi_pcihp.c
@@ -30,6 +30,7 @@
 #include <linux/types.h>
 #include <linux/pci.h>
 #include <linux/pci_hotplug.h>
+#include <linux/pci-acpi.h>
 #include <acpi/acpi.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/actypes.h>
@@ -299,7 +300,7 @@ free_and_return:
  *
  * @handle - the handle of the hotplug controller.
  */
-acpi_status acpi_run_oshp(acpi_handle handle)
+static acpi_status acpi_run_oshp(acpi_handle handle)
 {
         acpi_status             status;
         struct acpi_buffer      string = { ACPI_ALLOCATE_BUFFER, NULL };
@@ -322,9 +323,6 @@ acpi_status acpi_run_oshp(acpi_handle handle)
         kfree(string.pointer);
         return status;
 }
-EXPORT_SYMBOL_GPL(acpi_run_oshp);
-
-
 
 /* acpi_get_hp_params_from_firmware
  *
@@ -374,6 +372,85 @@ acpi_status acpi_get_hp_params_from_firmware(struct pci_bus *bus,
 }
 EXPORT_SYMBOL_GPL(acpi_get_hp_params_from_firmware);
 
+/**
+ * acpi_get_hp_hw_control_from_firmware
+ * @dev: the pci_dev of the bridge that has a hotplug controller
+ * @flags: requested control bits for _OSC
+ *
+ * Attempt to take hotplug control from firmware.
+ */
+int acpi_get_hp_hw_control_from_firmware(struct pci_dev *dev, u32 flags)
+{
+        acpi_status status;
+        acpi_handle chandle, handle = DEVICE_ACPI_HANDLE(&(dev->dev));
+        struct pci_dev *pdev = dev;
+        struct pci_bus *parent;
+        struct acpi_buffer string = { ACPI_ALLOCATE_BUFFER, NULL };
+
+        flags &= (OSC_PCI_EXPRESS_NATIVE_HP_CONTROL |
+                  OSC_SHPC_NATIVE_HP_CONTROL |
+                  OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL);
+        if (!flags) {
+                err("Invalid flags %u specified!\n", flags);
+                return -EINVAL;
+        }
+
+        /*
+         * Per PCI firmware specification, we should run the ACPI _OSC
+         * method to get control of hotplug hardware before using it. If
+         * an _OSC is missing, we look for an OSHP to do the same thing.
+         * To handle different BIOS behavior, we look for _OSC and OSHP
+         * within the scope of the hotplug controller and its parents,
+         * upto the host bridge under which this controller exists.
+         */
+        while (!handle) {
+                /*
+                 * This hotplug controller was not listed in the ACPI name
+                 * space at all. Try to get acpi handle of parent pci bus.
+                 */
+                if (!pdev || !pdev->bus->parent)
+                        break;
+                parent = pdev->bus->parent;
+                dbg("Could not find %s in acpi namespace, trying parent\n",
+                    pci_name(pdev));
+                if (!parent->self)
+                        /* Parent must be a host bridge */
+                        handle = acpi_get_pci_rootbridge_handle(
+                                        pci_domain_nr(parent),
+                                        parent->number);
+                else
+                        handle = DEVICE_ACPI_HANDLE(&(parent->self->dev));
+                pdev = parent->self;
+        }
+
+        while (handle) {
+                acpi_get_name(handle, ACPI_FULL_PATHNAME, &string);
+                dbg("Trying to get hotplug control for %s \n",
+                    (char *)string.pointer);
+                status = pci_osc_control_set(handle, flags);
+                if (status == AE_NOT_FOUND)
+                        status = acpi_run_oshp(handle);
+                if (ACPI_SUCCESS(status)) {
+                        dbg("Gained control for hotplug HW for pci %s (%s)\n",
+                            pci_name(dev), (char *)string.pointer);
+                        kfree(string.pointer);
+                        return 0;
+                }
+                if (acpi_root_bridge(handle))
+                        break;
+                chandle = handle;
+                status = acpi_get_parent(chandle, &handle);
+                if (ACPI_FAILURE(status))
+                        break;
+        }
+
+        dbg("Cannot get control of hotplug hardware for pci %s\n",
+            pci_name(dev));
+
+        kfree(string.pointer);
+        return -ENODEV;
+}
+EXPORT_SYMBOL(acpi_get_hp_hw_control_from_firmware);
 
 /* acpi_root_bridge - check to see if this acpi object is a root bridge
  *