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 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); 108 MODULE_AUTHOR("Paul Burton <paul.burton@mips.com>"); 109 MODULE_LICENSE("GPL"); 110