drivers/pci/hotplug/pciehp_acpi.c

   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 "pciehp.h"
  30
  31 #define PCIEHP_DETECT_PCIE      (0)
  32 #define PCIEHP_DETECT_ACPI      (1)
  33 #define PCIEHP_DETECT_AUTO      (2)
  34 #define PCIEHP_DETECT_DEFAULT   PCIEHP_DETECT_AUTO
  35
  36 static int slot_detection_mode;
  37 static char *pciehp_detect_mode;
  38 module_param(pciehp_detect_mode, charp, 0444);
  39 MODULE_PARM_DESC(pciehp_detect_mode,
  40          "Slot detection mode: pcie, acpi, auto\n"
  41          "  pcie          - Use PCIe based slot detection\n"
  42          "  acpi          - Use ACPI for slot detection\n"
  43          "  auto(default) - Auto select mode. Use acpi option if duplicate\n"
  44          "                  slot ids are found. Otherwise, use pcie option\n");
  45
  46 int pciehp_acpi_slot_detection_check(struct pci_dev *dev)
  47 {
  48         if (slot_detection_mode != PCIEHP_DETECT_ACPI)
  49                 return 0;
  50         if (acpi_pci_detect_ejectable(dev->subordinate))
  51                 return 0;
  52         return -ENODEV;
  53 }
  54
  55 static int __init parse_detect_mode(void)
  56 {
  57         if (!pciehp_detect_mode)
  58                 return PCIEHP_DETECT_DEFAULT;
  59         if (!strcmp(pciehp_detect_mode, "pcie"))
  60                 return PCIEHP_DETECT_PCIE;
  61         if (!strcmp(pciehp_detect_mode, "acpi"))
  62                 return PCIEHP_DETECT_ACPI;
  63         if (!strcmp(pciehp_detect_mode, "auto"))
  64                 return PCIEHP_DETECT_AUTO;
  65         warn("bad specifier '%s' for pciehp_detect_mode. Use default\n",
  66              pciehp_detect_mode);
  67         return PCIEHP_DETECT_DEFAULT;
  68 }
  69
  70 static int __initdata dup_slot_id;
  71 static int __initdata acpi_slot_detected;
  72 static struct list_head __initdata dummy_slots = LIST_HEAD_INIT(dummy_slots);
  73
  74 /* Dummy driver for dumplicate name detection */
  75 static int __init dummy_probe(struct pcie_device *dev)
  76 {
  77         int pos;
  78         u32 slot_cap;
  79         struct slot *slot, *tmp;
  80         struct pci_dev *pdev = dev->port;
  81         struct pci_bus *pbus = pdev->subordinate;
  82         /* Note: pciehp_detect_mode != PCIEHP_DETECT_ACPI here */
  83         if (pciehp_get_hp_hw_control_from_firmware(pdev))
  84                 return -ENODEV;
  85         if (!(pos = pci_find_capability(pdev, PCI_CAP_ID_EXP)))
  86                 return -ENODEV;
  87         pci_read_config_dword(pdev, pos + PCI_EXP_SLTCAP, &slot_cap);
  88         slot = kzalloc(sizeof(*slot), GFP_KERNEL);
  89         if (!slot)
  90                 return -ENOMEM;
  91         slot->number = slot_cap >> 19;
  92         list_for_each_entry(tmp, &dummy_slots, slot_list) {
  93                 if (tmp->number == slot->number)
  94                         dup_slot_id++;
  95         }
  96         list_add_tail(&slot->slot_list, &dummy_slots);
  97         if (!acpi_slot_detected && acpi_pci_detect_ejectable(pbus))
  98                 acpi_slot_detected = 1;
  99         return -ENODEV;         /* dummy driver always returns error */
 100 }
 101
 102 static struct pcie_port_service_driver __initdata dummy_driver = {
 103         .name           = "pciehp_dummy",
 104         .port_type      = PCIE_ANY_PORT,
 105         .service        = PCIE_PORT_SERVICE_HP,
 106         .probe          = dummy_probe,
 107 };
 108
 109 static int __init select_detection_mode(void)
 110 {
 111         struct slot *slot, *tmp;
 112         pcie_port_service_register(&dummy_driver);
 113         pcie_port_service_unregister(&dummy_driver);
 114         list_for_each_entry_safe(slot, tmp, &dummy_slots, slot_list) {
 115                 list_del(&slot->slot_list);
 116                 kfree(slot);
 117         }
 118         if (acpi_slot_detected && dup_slot_id)
 119                 return PCIEHP_DETECT_ACPI;
 120         return PCIEHP_DETECT_PCIE;
 121 }
 122
 123 void __init pciehp_acpi_slot_detection_init(void)
 124 {
 125         slot_detection_mode = parse_detect_mode();
 126         if (slot_detection_mode != PCIEHP_DETECT_AUTO)
 127                 goto out;
 128         slot_detection_mode = select_detection_mode();
 129 out:
 130         if (slot_detection_mode == PCIEHP_DETECT_ACPI)
 131                 info("Using ACPI for slot detection.\n");
 132 }