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
38struct dummy_slot {
39	u32 number;
40	struct list_head list;
41};
42
43static int slot_detection_mode;
44static char *pciehp_detect_mode;
45module_param(pciehp_detect_mode, charp, 0444);
46MODULE_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
53int 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
62static 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
77static int __initdata dup_slot_id;
78static int __initdata acpi_slot_detected;
79static struct list_head __initdata dummy_slots = LIST_HEAD_INIT(dummy_slots);
80
81/* Dummy driver for duplicate name detection */
82static 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
105static 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
112static int __init select_detection_mode(void)
113{
114	struct dummy_slot *slot, *tmp;
115
116	if (pcie_port_service_register(&dummy_driver))
117		return PCIEHP_DETECT_ACPI;
118	pcie_port_service_unregister(&dummy_driver);
119	list_for_each_entry_safe(slot, tmp, &dummy_slots, list) {
120		list_del(&slot->list);
121		kfree(slot);
122	}
123	if (acpi_slot_detected && dup_slot_id)
124		return PCIEHP_DETECT_ACPI;
125	return PCIEHP_DETECT_PCIE;
126}
127
128void __init pciehp_acpi_slot_detection_init(void)
129{
130	slot_detection_mode = parse_detect_mode();
131	if (slot_detection_mode != PCIEHP_DETECT_AUTO)
132		goto out;
133	slot_detection_mode = select_detection_mode();
134out:
135	if (slot_detection_mode == PCIEHP_DETECT_ACPI)
136		info("Using ACPI for slot detection.\n");
137}
138