shpchp: check firmware before taking control

[linux-2.6-omap-h63xx.git] / drivers / pci / hotplug / acpi_pcihp.c

diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
index f8c187a763bdcac12323191836079ea9943dde3e..93e37f0666ab5e2786484a775f107bbffd9b3ecd 100644 (file)
--- 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
  *