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