LXR linux/drivers/misc/pvpanic/pvpanic.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 *  Pvpanic Device Support
   4 *
   5 *  Copyright (C) 2013 Fujitsu.
   6 *  Copyright (C) 2018 ZTE.
   7 *  Copyright (C) 2021 Oracle.
   8 */
   9
  10#include <linux/io.h>
  11#include <linux/kernel.h>
  12#include <linux/kexec.h>
  13#include <linux/mod_devicetable.h>
  14#include <linux/module.h>
  15#include <linux/platform_device.h>
  16#include <linux/panic_notifier.h>
  17#include <linux/types.h>
  18#include <linux/cdev.h>
  19#include <linux/list.h>
  20
  21#include <uapi/misc/pvpanic.h>
  22
  23#include "pvpanic.h"
  24
  25MODULE_AUTHOR("Mihai Carabas <mihai.carabas@oracle.com>");
  26MODULE_DESCRIPTION("pvpanic device driver ");
  27MODULE_LICENSE("GPL");
  28
  29static struct list_head pvpanic_list;
  30static spinlock_t pvpanic_lock;
  31
  32static void
  33pvpanic_send_event(unsigned int event)
  34{
  35        struct pvpanic_instance *pi_cur;
  36
  37        spin_lock(&pvpanic_lock);
  38        list_for_each_entry(pi_cur, &pvpanic_list, list) {
  39                if (event & pi_cur->capability & pi_cur->events)
  40                        iowrite8(event, pi_cur->base);
  41        }
  42        spin_unlock(&pvpanic_lock);
  43}
  44
  45static int
  46pvpanic_panic_notify(struct notifier_block *nb, unsigned long code,
  47                     void *unused)
  48{
  49        unsigned int event = PVPANIC_PANICKED;
  50
  51        if (kexec_crash_loaded())
  52                event = PVPANIC_CRASH_LOADED;
  53
  54        pvpanic_send_event(event);
  55
  56        return NOTIFY_DONE;
  57}
  58
  59static struct notifier_block pvpanic_panic_nb = {
  60        .notifier_call = pvpanic_panic_notify,
  61        .priority = 1, /* let this called before broken drm_fb_helper */
  62};
  63
  64static void pvpanic_remove(void *param)
  65{
  66        struct pvpanic_instance *pi_cur, *pi_next;
  67        struct pvpanic_instance *pi = param;
  68
  69        spin_lock(&pvpanic_lock);
  70        list_for_each_entry_safe(pi_cur, pi_next, &pvpanic_list, list) {
  71                if (pi_cur == pi) {
  72                        list_del(&pi_cur->list);
  73                        break;
  74                }
  75        }
  76        spin_unlock(&pvpanic_lock);
  77}
  78
  79int devm_pvpanic_probe(struct device *dev, struct pvpanic_instance *pi)
  80{
  81        if (!pi || !pi->base)
  82                return -EINVAL;
  83
  84        spin_lock(&pvpanic_lock);
  85        list_add(&pi->list, &pvpanic_list);
  86        spin_unlock(&pvpanic_lock);
  87
  88        dev_set_drvdata(dev, pi);
  89
  90        return devm_add_action_or_reset(dev, pvpanic_remove, pi);
  91}
  92EXPORT_SYMBOL_GPL(devm_pvpanic_probe);
  93
  94static int pvpanic_init(void)
  95{
  96        INIT_LIST_HEAD(&pvpanic_list);
  97        spin_lock_init(&pvpanic_lock);
  98
  99        atomic_notifier_chain_register(&panic_notifier_list,
 100                                       &pvpanic_panic_nb);
 101
 102        return 0;
 103}
 104
 105static void pvpanic_exit(void)
 106{
 107        atomic_notifier_chain_unregister(&panic_notifier_list,
 108                                         &pvpanic_panic_nb);
 109
 110}
 111
 112module_init(pvpanic_init);
 113module_exit(pvpanic_exit);
 114