1/*
2 * Copyright (C) 2014 Imagination Technologies
3 * Author: Paul Burton <paul.burton@imgtec.com>
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation;  either version 2 of the  License, or (at your
8 * option) any later version.
9 */
10
11#include <linux/delay.h>
12#include <linux/init.h>
13#include <linux/io.h>
14#include <linux/pci.h>
15
16#include <asm/mach-malta/malta-pm.h>
17
18static struct pci_bus *pm_pci_bus;
19static resource_size_t pm_io_offset;
20
21int mips_pm_suspend(unsigned state)
22{
23	int spec_devid;
24	u16 sts;
25
26	if (!pm_pci_bus || !pm_io_offset)
27		return -ENODEV;
28
29	/* Ensure the power button status is clear */
30	while (1) {
31		sts = inw(pm_io_offset + PIIX4_FUNC3IO_PMSTS);
32		if (!(sts & PIIX4_FUNC3IO_PMSTS_PWRBTN_STS))
33			break;
34		outw(sts, pm_io_offset + PIIX4_FUNC3IO_PMSTS);
35	}
36
37	/* Enable entry to suspend */
38	outw(state | PIIX4_FUNC3IO_PMCNTRL_SUS_EN,
39	     pm_io_offset + PIIX4_FUNC3IO_PMCNTRL);
40
41	/* If the special cycle occurs too soon this doesn't work... */
42	mdelay(10);
43
44	/*
45	 * The PIIX4 will enter the suspend state only after seeing a special
46	 * cycle with the correct magic data on the PCI bus. Generate that
47	 * cycle now.
48	 */
49	spec_devid = PCI_DEVID(0, PCI_DEVFN(0x1f, 0x7));
50	pci_bus_write_config_dword(pm_pci_bus, spec_devid, 0,
51				   PIIX4_SUSPEND_MAGIC);
52
53	/* Give the system some time to power down */
54	mdelay(1000);
55
56	return 0;
57}
58
59static int __init malta_pm_setup(void)
60{
61	struct pci_dev *dev;
62	int res, io_region = PCI_BRIDGE_RESOURCES;
63
64	/* Find a reference to the PCI bus */
65	pm_pci_bus = pci_find_next_bus(NULL);
66	if (!pm_pci_bus) {
67		pr_warn("malta-pm: failed to find reference to PCI bus\n");
68		return -ENODEV;
69	}
70
71	/* Find the PIIX4 PM device */
72	dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
73			     PCI_DEVICE_ID_INTEL_82371AB_3, PCI_ANY_ID,
74			     PCI_ANY_ID, NULL);
75	if (!dev) {
76		pr_warn("malta-pm: failed to find PIIX4 PM\n");
77		return -ENODEV;
78	}
79
80	/* Request access to the PIIX4 PM IO registers */
81	res = pci_request_region(dev, io_region, "PIIX4 PM IO registers");
82	if (res) {
83		pr_warn("malta-pm: failed to request PM IO registers (%d)\n",
84			res);
85		pci_dev_put(dev);
86		return -ENODEV;
87	}
88
89	/* Find the offset to the PIIX4 PM IO registers */
90	pm_io_offset = pci_resource_start(dev, io_region);
91
92	pci_dev_put(dev);
93	return 0;
94}
95
96late_initcall(malta_pm_setup);
97