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 <acpi/acpi_bus.h>
  28#include <acpi/acpi_drivers.h>
  29
  30MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>");
  31MODULE_DESCRIPTION("pvpanic device driver");
  32MODULE_LICENSE("GPL");
  33
  34static int pvpanic_add(struct acpi_device *device);
  35static int pvpanic_remove(struct acpi_device *device);
  36
  37static const struct acpi_device_id pvpanic_device_ids[] = {
  38        { "QEMU0001", 0 },
  39        { "", 0 },
  40};
  41MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
  42
  43#define PVPANIC_PANICKED        (1 << 0)
  44
  45static u16 port;
  46
  47static struct acpi_driver pvpanic_driver = {
  48        .name =         "pvpanic",
  49        .class =        "QEMU",
  50        .ids =          pvpanic_device_ids,
  51        .ops =          {
  52                                .add =          pvpanic_add,
  53                                .remove =       pvpanic_remove,
  54                        },
  55        .owner =        THIS_MODULE,
  56};
  57
  58static void
  59pvpanic_send_event(unsigned int event)
  60{
  61        outb(event, port);
  62}
  63
  64static int
  65pvpanic_panic_notify(struct notifier_block *nb, unsigned long code,
  66                     void *unused)
  67{
  68        pvpanic_send_event(PVPANIC_PANICKED);
  69        return NOTIFY_DONE;
  70}
  71
  72static struct notifier_block pvpanic_panic_nb = {
  73        .notifier_call = pvpanic_panic_notify,
  74        .priority = 1, /* let this called before broken drm_fb_helper */
  75};
  76
  77
  78static acpi_status
  79pvpanic_walk_resources(struct acpi_resource *res, void *context)
  80{
  81        switch (res->type) {
  82        case ACPI_RESOURCE_TYPE_END_TAG:
  83                return AE_OK;
  84
  85        case ACPI_RESOURCE_TYPE_IO:
  86                port = res->data.io.minimum;
  87                return AE_OK;
  88
  89        default:
  90                return AE_ERROR;
  91        }
  92}
  93
  94static int pvpanic_add(struct acpi_device *device)
  95{
  96        acpi_status status;
  97        u64 ret;
  98
  99        status = acpi_evaluate_integer(device->handle, "_STA", NULL,
 100                                       &ret);
 101
 102        if (ACPI_FAILURE(status) || (ret & 0x0B) != 0x0B)
 103                return -ENODEV;
 104
 105        acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 106                            pvpanic_walk_resources, NULL);
 107
 108        if (!port)
 109                return -ENODEV;
 110
 111        atomic_notifier_chain_register(&panic_notifier_list,
 112                                       &pvpanic_panic_nb);
 113
 114        return 0;
 115}
 116
 117static int pvpanic_remove(struct acpi_device *device)
 118{
 119
 120        atomic_notifier_chain_unregister(&panic_notifier_list,
 121                                         &pvpanic_panic_nb);
 122        return 0;
 123}
 124
 125module_acpi_driver(pvpanic_driver);
 126