drivers/pci/pcie/pme/pcie_pme_acpi.c

   1 /*
   2  * PCIe Native PME support, ACPI-related part
   3  *
   4  * Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License V2.  See the file "COPYING" in the main directory of this archive
   8  * for more details.
   9  */
  10
  11 #include <linux/pci.h>
  12 #include <linux/kernel.h>
  13 #include <linux/errno.h>
  14 #include <linux/acpi.h>
  15 #include <linux/pci-acpi.h>
  16 #include <linux/pcieport_if.h>
  17
  18 /**
  19  * pcie_pme_acpi_setup - Request the ACPI BIOS to release control over PCIe PME.
  20  * @srv - PCIe PME service for a root port or event collector.
  21  *
  22  * Invoked when the PCIe bus type loads PCIe PME service driver.  To avoid
  23  * conflict with the BIOS PCIe support requires the BIOS to yield PCIe PME
  24  * control to the kernel.
  25  */
  26 int pcie_pme_acpi_setup(struct pcie_device *srv)
  27 {
  28         acpi_status status = AE_NOT_FOUND;
  29         struct pci_dev *port = srv->port;
  30         acpi_handle handle;
  31         u32 flags;
  32         int error = 0;
  33
  34         if (acpi_pci_disabled)
  35                 return -ENOSYS;
  36
  37         dev_info(&port->dev, "Requesting control of PCIe PME from ACPI BIOS\n");
  38
  39         handle = acpi_find_root_bridge_handle(port);
  40         if (!handle)
  41                 return -EINVAL;
  42
  43         flags = OSC_PCI_EXPRESS_PME_CONTROL |
  44                 OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL;
  45
  46         status = acpi_pci_osc_control_set(handle, &flags, flags);
  47         if (ACPI_FAILURE(status)) {
  48                 dev_info(&port->dev,
  49                         "Failed to receive control of PCIe PME service: %s\n",
  50                         (status == AE_SUPPORT || status == AE_NOT_FOUND) ?
  51                         "no _OSC support" : "ACPI _OSC failed");
  52                 error = -ENODEV;
  53         }
  54
  55         return error;
  56 }