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 struct dummy_slot {
  37         u32 number;
  38         struct list_head list;
  39 };
  40
  41 static int slot_detection_mode;
  42 static char *pciehp_detect_mode;
  43 module_param(pciehp_detect_mode, charp, 0444);
  44 MODULE_PARM_DESC(pciehp_detect_mode,
  45          "Slot detection mode: pcie, acpi, auto\n"
  46          "  pcie          - Use PCIe based slot detection\n"
  47          "  acpi          - Use ACPI for slot detection\n"
  48          "  auto(default) - Auto select mode. Use acpi option if duplicate\n"
  49          "                  slot ids are found. Otherwise, use pcie option\n");
  50
  51 int pciehp_acpi_slot_detection_check(struct pci_dev *dev)
  52 {
  53         if (slot_detection_mode != PCIEHP_DETECT_ACPI)
  54                 return 0;
  55         if (acpi_pci_detect_ejectable(DEVICE_ACPI_HANDLE(&dev->dev)))
  56                 return 0;
  57         return -ENODEV;
  58 }
  59
  60 static int __init parse_detect_mode(void)
  61 {
  62         if (!pciehp_detect_mode)
  63                 return PCIEHP_DETECT_DEFAULT;
  64         if (!strcmp(pciehp_detect_mode, "pcie"))
  65                 return PCIEHP_DETECT_PCIE;
  66         if (!strcmp(pciehp_detect_mode, "acpi"))
  67                 return PCIEHP_DETECT_ACPI;
  68         if (!strcmp(pciehp_detect_mode, "auto"))
  69                 return PCIEHP_DETECT_AUTO;
  70         warn("bad specifier '%s' for pciehp_detect_mode. Use default\n",
  71              pciehp_detect_mode);
  72         return PCIEHP_DETECT_DEFAULT;
  73 }
  74
  75 static int __initdata dup_slot_id;
  76 static int __initdata acpi_slot_detected;
  77 static struct list_head __initdata dummy_slots = LIST_HEAD_INIT(dummy_slots);
  78
  79 /* Dummy driver for dumplicate name detection */
  80 static int __init dummy_probe(struct pcie_device *dev)
  81 {
  82         int pos;
  83         u32 slot_cap;
  84         acpi_handle handle;
  85         struct dummy_slot *slot, *tmp;
  86         struct pci_dev *pdev = dev->port;
  87         /* Note: pciehp_detect_mode != PCIEHP_DETECT_ACPI here */
  88         if (pciehp_get_hp_hw_control_from_firmware(pdev))
  89                 return -ENODEV;
  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
 109 static 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
 116 static int __init select_detection_mode(void)
 117 {
 118         struct dummy_slot *slot, *tmp;
 119         pcie_port_service_register(&dummy_driver);
 120         pcie_port_service_unregister(&dummy_driver);
 121         list_for_each_entry_safe(slot, tmp, &dummy_slots, list) {
 122                 list_del(&slot->list);
 123                 kfree(slot);
 124         }
 125         if (acpi_slot_detected && dup_slot_id)
 126                 return PCIEHP_DETECT_ACPI;
 127         return PCIEHP_DETECT_PCIE;
 128 }
 129
 130 void __init pciehp_acpi_slot_detection_init(void)
 131 {
 132         slot_detection_mode = parse_detect_mode();
 133         if (slot_detection_mode != PCIEHP_DETECT_AUTO)
 134                 goto out;
 135         slot_detection_mode = select_detection_mode();
 136 out:
 137         if (slot_detection_mode == PCIEHP_DETECT_ACPI)
 138                 info("Using ACPI for slot detection.\n");
 139 }