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/*
* Copyright (C) 2014 Imagination Technologies
* Author: Paul Burton <paul.burton@mips.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/pci.h>
#include <asm/mach-malta/malta-pm.h>
static struct pci_bus *pm_pci_bus;
static resource_size_t pm_io_offset;
int mips_pm_suspend(unsigned state)
{
int spec_devid;
u16 sts;
if (!pm_pci_bus || !pm_io_offset)
return -ENODEV;
/* Ensure the power button status is clear */
while (1) {
sts = inw(pm_io_offset + PIIX4_FUNC3IO_PMSTS);
if (!(sts & PIIX4_FUNC3IO_PMSTS_PWRBTN_STS))
break;
outw(sts, pm_io_offset + PIIX4_FUNC3IO_PMSTS);
}
/* Enable entry to suspend */
outw(state | PIIX4_FUNC3IO_PMCNTRL_SUS_EN,
pm_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_pci_bus, spec_devid, 0,
PIIX4_SUSPEND_MAGIC);
/* Give the system some time to power down */
mdelay(1000);
return 0;
}
static int __init malta_pm_setup(void)
{
struct pci_dev *dev;
int res, io_region = PCI_BRIDGE_RESOURCES;
/* Find a reference to the PCI bus */
pm_pci_bus = pci_find_next_bus(NULL);
if (!pm_pci_bus) {
pr_warn("malta-pm: failed to find reference to PCI bus\n");
return -ENODEV;
}
/* Find the PIIX4 PM device */
dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
PCI_DEVICE_ID_INTEL_82371AB_3, PCI_ANY_ID,
PCI_ANY_ID, NULL);
if (!dev) {
pr_warn("malta-pm: failed to find PIIX4 PM\n");
return -ENODEV;
}
/* Request access to the PIIX4 PM IO registers */
res = pci_request_region(dev, io_region, "PIIX4 PM IO registers");
if (res) {
pr_warn("malta-pm: failed to request PM IO registers (%d)\n",
res);
pci_dev_put(dev);
return -ENODEV;
}
/* Find the offset to the PIIX4 PM IO registers */
pm_io_offset = pci_resource_start(dev, io_region);
pci_dev_put(dev);
return 0;
}
late_initcall(malta_pm_setup);
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