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 <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
  38 struct dummy_slot {
  39         u32 number;
  40         struct list_head list;
  41 };
  42
  43 static int slot_detection_mode;
  44 static char *pciehp_detect_mode;
  45 module_param(pciehp_detect_mode, charp, 0444);
  46 MODULE_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
  53 int 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(ACPI_HANDLE(&dev->dev)))
  58                 return 0;
  59         return -ENODEV;
  60 }
  61
  62 static 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
  77 static int __initdata dup_slot_id;
  78 static int __initdata acpi_slot_detected;
  79 static struct list_head __initdata dummy_slots = LIST_HEAD_INIT(dummy_slots);
  80
  81 /* Dummy driver for duplicate name detection */
  82 static int __init dummy_probe(struct pcie_device *dev)
  83 {
  84         u32 slot_cap;
  85         acpi_handle handle;
  86         struct dummy_slot *slot, *tmp;
  87         struct pci_dev *pdev = dev->port;
  88
  89         pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, &slot_cap);
  90         slot = kzalloc(sizeof(*slot), GFP_KERNEL);
  91         if (!slot)
  92                 return -ENOMEM;
  93         slot->number = (slot_cap & PCI_EXP_SLTCAP_PSN) >> 19;
  94         list_for_each_entry(tmp, &dummy_slots, list) {
  95                 if (tmp->number == slot->number)
  96                         dup_slot_id++;
  97         }
  98         list_add_tail(&slot->list, &dummy_slots);
  99         handle = ACPI_HANDLE(&pdev->dev);
 100         if (!acpi_slot_detected && acpi_pci_detect_ejectable(handle))
 101                 acpi_slot_detected = 1;
 102         return -ENODEV;         /* dummy driver always returns error */
 103 }
 104
 105 static struct pcie_port_service_driver __initdata dummy_driver = {
 106         .name           = "pciehp_dummy",
 107         .port_type      = PCIE_ANY_PORT,
 108         .service        = PCIE_PORT_SERVICE_HP,
 109         .probe          = dummy_probe,
 110 };
 111
 112 static int __init select_detection_mode(void)
 113 {
 114         struct dummy_slot *slot, *tmp;
 115         if (pcie_port_service_register(&dummy_driver))
 116                 return PCIEHP_DETECT_ACPI;
 117         pcie_port_service_unregister(&dummy_driver);
 118         list_for_each_entry_safe(slot, tmp, &dummy_slots, list) {
 119                 list_del(&slot->list);
 120                 kfree(slot);
 121         }
 122         if (acpi_slot_detected && dup_slot_id)
 123                 return PCIEHP_DETECT_ACPI;
 124         return PCIEHP_DETECT_PCIE;
 125 }
 126
 127 void __init pciehp_acpi_slot_detection_init(void)
 128 {
 129         slot_detection_mode = parse_detect_mode();
 130         if (slot_detection_mode != PCIEHP_DETECT_AUTO)
 131                 goto out;
 132         slot_detection_mode = select_detection_mode();
 133 out:
 134         if (slot_detection_mode == PCIEHP_DETECT_ACPI)
 135                 info("Using ACPI for slot detection.\n");
 136 }