LXR linux/drivers/platform/x86/pvpanic.c

   1/*
   2 *  pvpanic.c - pvpanic Device Support
   3 *
   4 *  Copyright (C) 2013 Fujitsu.
   5 *
   6 *  This program is free software; you can redistribute it and/or modify
   7 *  it under the terms of the GNU General Public License as published by
   8 *  the Free Software Foundation; either version 2 of the License, or
   9 *  (at your option) any later version.
  10 *
  11 *  This program is distributed in the hope that it will be useful,
  12 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 *  GNU General Public License for more details.
  15 *
  16 *  You should have received a copy of the GNU General Public License
  17 *  along with this program; if not, write to the Free Software
  18 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  19 */
  20
  21#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  22
  23#include <linux/kernel.h>
  24#include <linux/module.h>
  25#include <linux/init.h>
  26#include <linux/types.h>
  27#include <linux/acpi.h>
  28
  29MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>");
  30MODULE_DESCRIPTION("pvpanic device driver");
  31MODULE_LICENSE("GPL");
  32
  33static int pvpanic_add(struct acpi_device *device);
  34static int pvpanic_remove(struct acpi_device *device);
  35
  36static const struct acpi_device_id pvpanic_device_ids[] = {
  37        { "QEMU0001", 0 },
  38        { "", 0 },
  39};
  40MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
  41
  42#define PVPANIC_PANICKED        (1 << 0)
  43
  44static u16 port;
  45
  46static struct acpi_driver pvpanic_driver = {
  47        .name =         "pvpanic",
  48        .class =        "QEMU",
  49        .ids =          pvpanic_device_ids,
  50        .ops =          {
  51                                .add =          pvpanic_add,
  52                                .remove =       pvpanic_remove,
  53                        },
  54        .owner =        THIS_MODULE,
  55};
  56
  57static void
  58pvpanic_send_event(unsigned int event)
  59{
  60        outb(event, port);
  61}
  62
  63static int
  64pvpanic_panic_notify(struct notifier_block *nb, unsigned long code,
  65                     void *unused)
  66{
  67        pvpanic_send_event(PVPANIC_PANICKED);
  68        return NOTIFY_DONE;
  69}
  70
  71static struct notifier_block pvpanic_panic_nb = {
  72        .notifier_call = pvpanic_panic_notify,
  73        .priority = 1, /* let this called before broken drm_fb_helper */
  74};
  75
  76
  77static acpi_status
  78pvpanic_walk_resources(struct acpi_resource *res, void *context)
  79{
  80        switch (res->type) {
  81        case ACPI_RESOURCE_TYPE_END_TAG:
  82                return AE_OK;
  83
  84        case ACPI_RESOURCE_TYPE_IO:
  85                port = res->data.io.minimum;
  86                return AE_OK;
  87
  88        default:
  89                return AE_ERROR;
  90        }
  91}
  92
  93static int pvpanic_add(struct acpi_device *device)
  94{
  95        int ret;
  96
  97        ret = acpi_bus_get_status(device);
  98        if (ret < 0)
  99                return ret;
 100
 101        if (!device->status.enabled || !device->status.functional)
 102                return -ENODEV;
 103
 104        acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 105                            pvpanic_walk_resources, NULL);
 106
 107        if (!port)
 108                return -ENODEV;
 109
 110        atomic_notifier_chain_register(&panic_notifier_list,
 111                                       &pvpanic_panic_nb);
 112
 113        return 0;
 114}
 115
 116static int pvpanic_remove(struct acpi_device *device)
 117{
 118
 119        atomic_notifier_chain_unregister(&panic_notifier_list,
 120                                         &pvpanic_panic_nb);
 121        return 0;
 122}
 123
 124module_acpi_driver(pvpanic_driver);
 125