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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
29676833 PB |
2 | /* |
3 | * Copyright (C) 2016 Imagination Technologies | |
fb615d61 | 4 | * Author: Paul Burton <paul.burton@mips.com> |
29676833 PB |
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 | ||
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 | ||
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 | ||
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); | |
fb615d61 | 108 | MODULE_AUTHOR("Paul Burton <paul.burton@mips.com>"); |
29676833 | 109 | MODULE_LICENSE("GPL"); |