cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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stmp3xxx_rtc_wdt.c (3874B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Watchdog driver for the RTC based watchdog in STMP3xxx and i.MX23/28
      4 *
      5 * Author: Wolfram Sang <kernel@pengutronix.de>
      6 *
      7 * Copyright (C) 2011-12 Wolfram Sang, Pengutronix
      8 */
      9#include <linux/kernel.h>
     10#include <linux/module.h>
     11#include <linux/watchdog.h>
     12#include <linux/platform_device.h>
     13#include <linux/stmp3xxx_rtc_wdt.h>
     14#include <linux/notifier.h>
     15#include <linux/reboot.h>
     16
     17#define WDOG_TICK_RATE 1000 /* 1 kHz clock */
     18#define STMP3XXX_DEFAULT_TIMEOUT 19
     19#define STMP3XXX_MAX_TIMEOUT (UINT_MAX / WDOG_TICK_RATE)
     20
     21static int heartbeat = STMP3XXX_DEFAULT_TIMEOUT;
     22module_param(heartbeat, uint, 0);
     23MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat period in seconds from 1 to "
     24		 __MODULE_STRING(STMP3XXX_MAX_TIMEOUT) ", default "
     25		 __MODULE_STRING(STMP3XXX_DEFAULT_TIMEOUT));
     26
     27static int wdt_start(struct watchdog_device *wdd)
     28{
     29	struct device *dev = watchdog_get_drvdata(wdd);
     30	struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);
     31
     32	pdata->wdt_set_timeout(dev->parent, wdd->timeout * WDOG_TICK_RATE);
     33	return 0;
     34}
     35
     36static int wdt_stop(struct watchdog_device *wdd)
     37{
     38	struct device *dev = watchdog_get_drvdata(wdd);
     39	struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(dev);
     40
     41	pdata->wdt_set_timeout(dev->parent, 0);
     42	return 0;
     43}
     44
     45static int wdt_set_timeout(struct watchdog_device *wdd, unsigned new_timeout)
     46{
     47	wdd->timeout = new_timeout;
     48	return wdt_start(wdd);
     49}
     50
     51static const struct watchdog_info stmp3xxx_wdt_ident = {
     52	.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
     53	.identity = "STMP3XXX RTC Watchdog",
     54};
     55
     56static const struct watchdog_ops stmp3xxx_wdt_ops = {
     57	.owner = THIS_MODULE,
     58	.start = wdt_start,
     59	.stop = wdt_stop,
     60	.set_timeout = wdt_set_timeout,
     61};
     62
     63static struct watchdog_device stmp3xxx_wdd = {
     64	.info = &stmp3xxx_wdt_ident,
     65	.ops = &stmp3xxx_wdt_ops,
     66	.min_timeout = 1,
     67	.max_timeout = STMP3XXX_MAX_TIMEOUT,
     68	.status = WATCHDOG_NOWAYOUT_INIT_STATUS,
     69};
     70
     71static int wdt_notify_sys(struct notifier_block *nb, unsigned long code,
     72			  void *unused)
     73{
     74	switch (code) {
     75	case SYS_DOWN:	/* keep enabled, system might crash while going down */
     76		break;
     77	case SYS_HALT:	/* allow the system to actually halt */
     78	case SYS_POWER_OFF:
     79		wdt_stop(&stmp3xxx_wdd);
     80		break;
     81	}
     82
     83	return NOTIFY_DONE;
     84}
     85
     86static struct notifier_block wdt_notifier = {
     87	.notifier_call = wdt_notify_sys,
     88};
     89
     90static int stmp3xxx_wdt_probe(struct platform_device *pdev)
     91{
     92	struct device *dev = &pdev->dev;
     93	int ret;
     94
     95	watchdog_set_drvdata(&stmp3xxx_wdd, dev);
     96
     97	stmp3xxx_wdd.timeout = clamp_t(unsigned, heartbeat, 1, STMP3XXX_MAX_TIMEOUT);
     98	stmp3xxx_wdd.parent = dev;
     99
    100	ret = devm_watchdog_register_device(dev, &stmp3xxx_wdd);
    101	if (ret < 0)
    102		return ret;
    103
    104	if (register_reboot_notifier(&wdt_notifier))
    105		dev_warn(dev, "cannot register reboot notifier\n");
    106
    107	dev_info(dev, "initialized watchdog with heartbeat %ds\n",
    108		 stmp3xxx_wdd.timeout);
    109	return 0;
    110}
    111
    112static int stmp3xxx_wdt_remove(struct platform_device *pdev)
    113{
    114	unregister_reboot_notifier(&wdt_notifier);
    115	return 0;
    116}
    117
    118static int __maybe_unused stmp3xxx_wdt_suspend(struct device *dev)
    119{
    120	struct watchdog_device *wdd = &stmp3xxx_wdd;
    121
    122	if (watchdog_active(wdd))
    123		return wdt_stop(wdd);
    124
    125	return 0;
    126}
    127
    128static int __maybe_unused stmp3xxx_wdt_resume(struct device *dev)
    129{
    130	struct watchdog_device *wdd = &stmp3xxx_wdd;
    131
    132	if (watchdog_active(wdd))
    133		return wdt_start(wdd);
    134
    135	return 0;
    136}
    137
    138static SIMPLE_DEV_PM_OPS(stmp3xxx_wdt_pm_ops,
    139			 stmp3xxx_wdt_suspend, stmp3xxx_wdt_resume);
    140
    141static struct platform_driver stmp3xxx_wdt_driver = {
    142	.driver = {
    143		.name = "stmp3xxx_rtc_wdt",
    144		.pm = &stmp3xxx_wdt_pm_ops,
    145	},
    146	.probe = stmp3xxx_wdt_probe,
    147	.remove = stmp3xxx_wdt_remove,
    148};
    149module_platform_driver(stmp3xxx_wdt_driver);
    150
    151MODULE_DESCRIPTION("STMP3XXX RTC Watchdog Driver");
    152MODULE_LICENSE("GPL v2");
    153MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");