LXR linux/arch/mips/mti-malta/malta-pm.c

   1/*
   2 * Copyright (C) 2014 Imagination Technologies
   3 * Author: Paul Burton <paul.burton@imgtec.com>
   4 *
   5 * This program is free software; you can redistribute it and/or modify it
   6 * under the terms of the GNU General Public License as published by the
   7 * Free Software Foundation;  either version 2 of the  License, or (at your
   8 * option) any later version.
   9 */
  10
  11#include <linux/delay.h>
  12#include <linux/init.h>
  13#include <linux/io.h>
  14#include <linux/pci.h>
  15
  16#include <asm/mach-malta/malta-pm.h>
  17
  18static struct pci_bus *pm_pci_bus;
  19static resource_size_t pm_io_offset;
  20
  21int mips_pm_suspend(unsigned state)
  22{
  23        int spec_devid;
  24        u16 sts;
  25
  26        if (!pm_pci_bus || !pm_io_offset)
  27                return -ENODEV;
  28
  29        /* Ensure the power button status is clear */
  30        while (1) {
  31                sts = inw(pm_io_offset + PIIX4_FUNC3IO_PMSTS);
  32                if (!(sts & PIIX4_FUNC3IO_PMSTS_PWRBTN_STS))
  33                        break;
  34                outw(sts, pm_io_offset + PIIX4_FUNC3IO_PMSTS);
  35        }
  36
  37        /* Enable entry to suspend */
  38        outw(state | PIIX4_FUNC3IO_PMCNTRL_SUS_EN,
  39             pm_io_offset + PIIX4_FUNC3IO_PMCNTRL);
  40
  41        /* If the special cycle occurs too soon this doesn't work... */
  42        mdelay(10);
  43
  44        /*
  45         * The PIIX4 will enter the suspend state only after seeing a special
  46         * cycle with the correct magic data on the PCI bus. Generate that
  47         * cycle now.
  48         */
  49        spec_devid = PCI_DEVID(0, PCI_DEVFN(0x1f, 0x7));
  50        pci_bus_write_config_dword(pm_pci_bus, spec_devid, 0,
  51                                   PIIX4_SUSPEND_MAGIC);
  52
  53        /* Give the system some time to power down */
  54        mdelay(1000);
  55
  56        return 0;
  57}
  58
  59static int __init malta_pm_setup(void)
  60{
  61        struct pci_dev *dev;
  62        int res, io_region = PCI_BRIDGE_RESOURCES;
  63
  64        /* Find a reference to the PCI bus */
  65        pm_pci_bus = pci_find_next_bus(NULL);
  66        if (!pm_pci_bus) {
  67                pr_warn("malta-pm: failed to find reference to PCI bus\n");
  68                return -ENODEV;
  69        }
  70
  71        /* Find the PIIX4 PM device */
  72        dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
  73                             PCI_DEVICE_ID_INTEL_82371AB_3, PCI_ANY_ID,
  74                             PCI_ANY_ID, NULL);
  75        if (!dev) {
  76                pr_warn("malta-pm: failed to find PIIX4 PM\n");
  77                return -ENODEV;
  78        }
  79
  80        /* Request access to the PIIX4 PM IO registers */
  81        res = pci_request_region(dev, io_region, "PIIX4 PM IO registers");
  82        if (res) {
  83                pr_warn("malta-pm: failed to request PM IO registers (%d)\n",
  84                        res);
  85                pci_dev_put(dev);
  86                return -ENODEV;
  87        }
  88
  89        /* Find the offset to the PIIX4 PM IO registers */
  90        pm_io_offset = pci_resource_start(dev, io_region);
  91
  92        pci_dev_put(dev);
  93        return 0;
  94}
  95
  96late_initcall(malta_pm_setup);
  97