1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2016 Imagination Technologies
4 * Author: Paul Burton <paul.burton@mips.com>
5 */
6
7 #include <linux/delay.h>
8 #include <linux/io.h>
9 #include <linux/module.h>
10 #include <linux/pci.h>
11 #include <linux/pm.h>
12
13 static struct pci_dev *pm_dev;
14 static resource_size_t io_offset;
15
16 enum piix4_pm_io_reg {
17 PIIX4_FUNC3IO_PMSTS = 0x00,
18 #define PIIX4_FUNC3IO_PMSTS_PWRBTN_STS BIT(8)
19 PIIX4_FUNC3IO_PMCNTRL = 0x04,
20 #define PIIX4_FUNC3IO_PMCNTRL_SUS_EN BIT(13)
21 #define PIIX4_FUNC3IO_PMCNTRL_SUS_TYP_SOFF (0x0 << 10)
22 };
23
24 #define PIIX4_SUSPEND_MAGIC 0x00120002
25
26 static const int piix4_pm_io_region = PCI_BRIDGE_RESOURCES;
27
piix4_poweroff(void)28 static void piix4_poweroff(void)
29 {
30 int spec_devid;
31 u16 sts;
32
33 /* Ensure the power button status is clear */
34 while (1) {
35 sts = inw(io_offset + PIIX4_FUNC3IO_PMSTS);
36 if (!(sts & PIIX4_FUNC3IO_PMSTS_PWRBTN_STS))
37 break;
38 outw(sts, io_offset + PIIX4_FUNC3IO_PMSTS);
39 }
40
41 /* Enable entry to suspend */
42 outw(PIIX4_FUNC3IO_PMCNTRL_SUS_TYP_SOFF | PIIX4_FUNC3IO_PMCNTRL_SUS_EN,
43 io_offset + PIIX4_FUNC3IO_PMCNTRL);
44
45 /* If the special cycle occurs too soon this doesn't work... */
46 mdelay(10);
47
48 /*
49 * The PIIX4 will enter the suspend state only after seeing a special
50 * cycle with the correct magic data on the PCI bus. Generate that
51 * cycle now.
52 */
53 spec_devid = PCI_DEVID(0, PCI_DEVFN(0x1f, 0x7));
54 pci_bus_write_config_dword(pm_dev->bus, spec_devid, 0,
55 PIIX4_SUSPEND_MAGIC);
56
57 /* Give the system some time to power down, then error */
58 mdelay(1000);
59 pr_emerg("Unable to poweroff system\n");
60 }
61
piix4_poweroff_probe(struct pci_dev * dev,const struct pci_device_id * id)62 static int piix4_poweroff_probe(struct pci_dev *dev,
63 const struct pci_device_id *id)
64 {
65 int res;
66
67 if (pm_dev)
68 return -EINVAL;
69
70 /* Request access to the PIIX4 PM IO registers */
71 res = pci_request_region(dev, piix4_pm_io_region,
72 "PIIX4 PM IO registers");
73 if (res) {
74 dev_err(&dev->dev, "failed to request PM IO registers: %d\n",
75 res);
76 return res;
77 }
78
79 pm_dev = dev;
80 io_offset = pci_resource_start(dev, piix4_pm_io_region);
81 pm_power_off = piix4_poweroff;
82
83 return 0;
84 }
85
piix4_poweroff_remove(struct pci_dev * dev)86 static void piix4_poweroff_remove(struct pci_dev *dev)
87 {
88 if (pm_power_off == piix4_poweroff)
89 pm_power_off = NULL;
90
91 pci_release_region(dev, piix4_pm_io_region);
92 pm_dev = NULL;
93 }
94
95 static const struct pci_device_id piix4_poweroff_ids[] = {
96 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371AB_3) },
97 { 0 },
98 };
99
100 static struct pci_driver piix4_poweroff_driver = {
101 .name = "piix4-poweroff",
102 .id_table = piix4_poweroff_ids,
103 .probe = piix4_poweroff_probe,
104 .remove = piix4_poweroff_remove,
105 };
106
107 module_pci_driver(piix4_poweroff_driver);
108 MODULE_AUTHOR("Paul Burton <paul.burton@mips.com>");
109 MODULE_LICENSE("GPL");
110