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
pciehp_acpi_slot_detection_check(struct pci_dev * dev)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(DEVICE_ACPI_HANDLE(&dev->dev)))
58 return 0;
59 return -ENODEV;
60 }
61
parse_detect_mode(void)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 dumplicate name detection */
dummy_probe(struct pcie_device * dev)82 static 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
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
select_detection_mode(void)116 static 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
pciehp_acpi_slot_detection_init(void)131 void __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();
137 out:
138 if (slot_detection_mode == PCIEHP_DETECT_ACPI)
139 info("Using ACPI for slot detection.\n");
140 }
141