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