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
  18 static struct pci_bus *pm_pci_bus;
  19 static resource_size_t pm_io_offset;
  20
  21 int 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
  59 static 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
  96 late_initcall(malta_pm_setup);