linux/drivers/pci/hotplug/pciehp_acpi.c
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   1/*
   2 * ACPI related functions for PCI Express Hot Plug driver.
   3 *
   4 * Copyright (C) 2008 Kenji Kaneshige
   5 * Copyright (C) 2008 Fujitsu Limited.
   6 *
   7 * All rights reserved.
   8 *
   9 * This program is free software; you can redistribute it and/or modify
  10 * it under the terms of the GNU General Public License as published by
  11 * the Free Software Foundation; either version 2 of the License, or (at
  12 * your option) any later version.
  13 *
  14 * This program is distributed in the hope that it will be useful, but
  15 * WITHOUT ANY WARRANTY; without even the implied warranty of
  16 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  17 * NON INFRINGEMENT.  See the GNU General Public License for more
  18 * details.
  19 *
  20 * You should have received a copy of the GNU General Public License
  21 * along with this program; if not, write to the Free Software
  22 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23 *
  24 */
  25
  26#include <linux/acpi.h>
  27#include <linux/pci.h>
  28#include <linux/pci_hotplug.h>
  29#include <linux/slab.h>
  30#include <linux/module.h>
  31#include "pciehp.h"
  32
  33#define PCIEHP_DETECT_PCIE      (0)
  34#define PCIEHP_DETECT_ACPI      (1)
  35#define PCIEHP_DETECT_AUTO      (2)
  36#define PCIEHP_DETECT_DEFAULT   PCIEHP_DETECT_AUTO
  37
  38struct dummy_slot {
  39        u32 number;
  40        struct list_head list;
  41};
  42
  43static int slot_detection_mode;
  44static char *pciehp_detect_mode;
  45module_param(pciehp_detect_mode, charp, 0444);
  46MODULE_PARM_DESC(pciehp_detect_mode,
  47         "Slot detection mode: pcie, acpi, auto\n"
  48         "  pcie          - Use PCIe based slot detection\n"
  49         "  acpi          - Use ACPI for slot detection\n"
  50         "  auto(default) - Auto select mode. Use acpi option if duplicate\n"
  51         "                  slot ids are found. Otherwise, use pcie option\n");
  52
  53int pciehp_acpi_slot_detection_check(struct pci_dev *dev)
  54{
  55        if (slot_detection_mode != PCIEHP_DETECT_ACPI)
  56                return 0;
  57        if (acpi_pci_detect_ejectable(DEVICE_ACPI_HANDLE(&dev->dev)))
  58                return 0;
  59        return -ENODEV;
  60}
  61
  62static int __init parse_detect_mode(void)
  63{
  64        if (!pciehp_detect_mode)
  65                return PCIEHP_DETECT_DEFAULT;
  66        if (!strcmp(pciehp_detect_mode, "pcie"))
  67                return PCIEHP_DETECT_PCIE;
  68        if (!strcmp(pciehp_detect_mode, "acpi"))
  69                return PCIEHP_DETECT_ACPI;
  70        if (!strcmp(pciehp_detect_mode, "auto"))
  71                return PCIEHP_DETECT_AUTO;
  72        warn("bad specifier '%s' for pciehp_detect_mode. Use default\n",
  73             pciehp_detect_mode);
  74        return PCIEHP_DETECT_DEFAULT;
  75}
  76
  77static int __initdata dup_slot_id;
  78static int __initdata acpi_slot_detected;
  79static struct list_head __initdata dummy_slots = LIST_HEAD_INIT(dummy_slots);
  80
  81/* Dummy driver for dumplicate name detection */
  82static int __init dummy_probe(struct pcie_device *dev)
  83{
  84        int pos;
  85        u32 slot_cap;
  86        acpi_handle handle;
  87        struct dummy_slot *slot, *tmp;
  88        struct pci_dev *pdev = dev->port;
  89
  90        pos = pci_pcie_cap(pdev);
  91        if (!pos)
  92                return -ENODEV;
  93        pci_read_config_dword(pdev, pos + PCI_EXP_SLTCAP, &slot_cap);
  94        slot = kzalloc(sizeof(*slot), GFP_KERNEL);
  95        if (!slot)
  96                return -ENOMEM;
  97        slot->number = slot_cap >> 19;
  98        list_for_each_entry(tmp, &dummy_slots, list) {
  99                if (tmp->number == slot->number)
 100                        dup_slot_id++;
 101        }
 102        list_add_tail(&slot->list, &dummy_slots);
 103        handle = DEVICE_ACPI_HANDLE(&pdev->dev);
 104        if (!acpi_slot_detected && acpi_pci_detect_ejectable(handle))
 105                acpi_slot_detected = 1;
 106        return -ENODEV;         /* dummy driver always returns error */
 107}
 108
 109static struct pcie_port_service_driver __initdata dummy_driver = {
 110        .name           = "pciehp_dummy",
 111        .port_type      = PCIE_ANY_PORT,
 112        .service        = PCIE_PORT_SERVICE_HP,
 113        .probe          = dummy_probe,
 114};
 115
 116static int __init select_detection_mode(void)
 117{
 118        struct dummy_slot *slot, *tmp;
 119        if (pcie_port_service_register(&dummy_driver))
 120                return PCIEHP_DETECT_ACPI;
 121        pcie_port_service_unregister(&dummy_driver);
 122        list_for_each_entry_safe(slot, tmp, &dummy_slots, list) {
 123                list_del(&slot->list);
 124                kfree(slot);
 125        }
 126        if (acpi_slot_detected && dup_slot_id)
 127                return PCIEHP_DETECT_ACPI;
 128        return PCIEHP_DETECT_PCIE;
 129}
 130
 131void __init pciehp_acpi_slot_detection_init(void)
 132{
 133        slot_detection_mode = parse_detect_mode();
 134        if (slot_detection_mode != PCIEHP_DETECT_AUTO)
 135                goto out;
 136        slot_detection_mode = select_detection_mode();
 137out:
 138        if (slot_detection_mode == PCIEHP_DETECT_ACPI)
 139                info("Using ACPI for slot detection.\n");
 140}
 141