// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2016 Imagination Technologies
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* Author: Paul Burton <paul.burton@mips.com>
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*/
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#include <linux/delay.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/pci.h>
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#include <linux/pm.h>
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static struct pci_dev *pm_dev;
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static resource_size_t io_offset;
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enum piix4_pm_io_reg {
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PIIX4_FUNC3IO_PMSTS = 0x00,
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#define PIIX4_FUNC3IO_PMSTS_PWRBTN_STS BIT(8)
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PIIX4_FUNC3IO_PMCNTRL = 0x04,
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#define PIIX4_FUNC3IO_PMCNTRL_SUS_EN BIT(13)
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#define PIIX4_FUNC3IO_PMCNTRL_SUS_TYP_SOFF (0x0 << 10)
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};
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#define PIIX4_SUSPEND_MAGIC 0x00120002
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static const int piix4_pm_io_region = PCI_BRIDGE_RESOURCES;
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static void piix4_poweroff(void)
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{
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int spec_devid;
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u16 sts;
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/* Ensure the power button status is clear */
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while (1) {
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sts = inw(io_offset + PIIX4_FUNC3IO_PMSTS);
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if (!(sts & PIIX4_FUNC3IO_PMSTS_PWRBTN_STS))
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break;
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outw(sts, io_offset + PIIX4_FUNC3IO_PMSTS);
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}
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/* Enable entry to suspend */
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outw(PIIX4_FUNC3IO_PMCNTRL_SUS_TYP_SOFF | PIIX4_FUNC3IO_PMCNTRL_SUS_EN,
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io_offset + PIIX4_FUNC3IO_PMCNTRL);
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/* If the special cycle occurs too soon this doesn't work... */
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mdelay(10);
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/*
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* The PIIX4 will enter the suspend state only after seeing a special
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* cycle with the correct magic data on the PCI bus. Generate that
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* cycle now.
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*/
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spec_devid = PCI_DEVID(0, PCI_DEVFN(0x1f, 0x7));
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pci_bus_write_config_dword(pm_dev->bus, spec_devid, 0,
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PIIX4_SUSPEND_MAGIC);
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/* Give the system some time to power down, then error */
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mdelay(1000);
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pr_emerg("Unable to poweroff system\n");
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}
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static int piix4_poweroff_probe(struct pci_dev *dev,
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const struct pci_device_id *id)
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{
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int res;
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if (pm_dev)
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return -EINVAL;
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/* Request access to the PIIX4 PM IO registers */
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res = pci_request_region(dev, piix4_pm_io_region,
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"PIIX4 PM IO registers");
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if (res) {
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dev_err(&dev->dev, "failed to request PM IO registers: %d\n",
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res);
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return res;
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}
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pm_dev = dev;
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io_offset = pci_resource_start(dev, piix4_pm_io_region);
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pm_power_off = piix4_poweroff;
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return 0;
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}
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static void piix4_poweroff_remove(struct pci_dev *dev)
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{
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if (pm_power_off == piix4_poweroff)
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pm_power_off = NULL;
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pci_release_region(dev, piix4_pm_io_region);
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pm_dev = NULL;
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}
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static const struct pci_device_id piix4_poweroff_ids[] = {
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{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371AB_3) },
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{ 0 },
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};
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static struct pci_driver piix4_poweroff_driver = {
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.name = "piix4-poweroff",
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.id_table = piix4_poweroff_ids,
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.probe = piix4_poweroff_probe,
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.remove = piix4_poweroff_remove,
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};
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module_pci_driver(piix4_poweroff_driver);
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MODULE_AUTHOR("Paul Burton <paul.burton@mips.com>");
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MODULE_LICENSE("GPL");
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