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);