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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Copyright (C) 2016 Imagination Technologies4 * 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 13static struct pci_dev *pm_dev;14static resource_size_t io_offset;15 16enum 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 0x0012000225 26static const int piix4_pm_io_region = PCI_BRIDGE_RESOURCES;27 28static 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 special50 * cycle with the correct magic data on the PCI bus. Generate that51 * 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 62static 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 86static 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 95static 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 100static 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 107module_pci_driver(piix4_poweroff_driver);108MODULE_AUTHOR("Paul Burton <paul.burton@mips.com>");109MODULE_DESCRIPTION("Intel PIIX4 power-off driver");110MODULE_LICENSE("GPL");111