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// 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");
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