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(DEVICE_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 dumplicate name detection */
 82static 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
109static 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
116static 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
131void __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();
137out:
138	if (slot_detection_mode == PCIEHP_DETECT_ACPI)
139		info("Using ACPI for slot detection.\n");
140}