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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ep93xx_wdt.c (3696B)

      1/*
      2 * Watchdog driver for Cirrus Logic EP93xx family of devices.
      3 *
      4 * Copyright (c) 2004 Ray Lehtiniemi
      5 * Copyright (c) 2006 Tower Technologies
      6 * Based on ep93xx driver, bits from alim7101_wdt.c
      7 *
      8 * Authors: Ray Lehtiniemi <rayl@mail.com>,
      9 *	Alessandro Zummo <a.zummo@towertech.it>
     10 *
     11 * Copyright (c) 2012 H Hartley Sweeten <hsweeten@visionengravers.com>
     12 *	Convert to a platform device and use the watchdog framework API
     13 *
     14 * This file is licensed under the terms of the GNU General Public
     15 * License version 2. This program is licensed "as is" without any
     16 * warranty of any kind, whether express or implied.
     17 *
     18 * This watchdog fires after 250msec, which is a too short interval
     19 * for us to rely on the user space daemon alone. So we ping the
     20 * wdt each ~200msec and eventually stop doing it if the user space
     21 * daemon dies.
     22 */
     23
     24#include <linux/platform_device.h>
     25#include <linux/module.h>
     26#include <linux/watchdog.h>
     27#include <linux/io.h>
     28
     29/* default timeout (secs) */
     30#define WDT_TIMEOUT 30
     31
     32static bool nowayout = WATCHDOG_NOWAYOUT;
     33module_param(nowayout, bool, 0);
     34MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
     35
     36static unsigned int timeout;
     37module_param(timeout, uint, 0);
     38MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds.");
     39
     40#define EP93XX_WATCHDOG		0x00
     41#define EP93XX_WDSTATUS		0x04
     42
     43struct ep93xx_wdt_priv {
     44	void __iomem *mmio;
     45	struct watchdog_device wdd;
     46};
     47
     48static int ep93xx_wdt_start(struct watchdog_device *wdd)
     49{
     50	struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
     51
     52	writel(0xaaaa, priv->mmio + EP93XX_WATCHDOG);
     53
     54	return 0;
     55}
     56
     57static int ep93xx_wdt_stop(struct watchdog_device *wdd)
     58{
     59	struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
     60
     61	writel(0xaa55, priv->mmio + EP93XX_WATCHDOG);
     62
     63	return 0;
     64}
     65
     66static int ep93xx_wdt_ping(struct watchdog_device *wdd)
     67{
     68	struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
     69
     70	writel(0x5555, priv->mmio + EP93XX_WATCHDOG);
     71
     72	return 0;
     73}
     74
     75static const struct watchdog_info ep93xx_wdt_ident = {
     76	.options	= WDIOF_CARDRESET |
     77			  WDIOF_SETTIMEOUT |
     78			  WDIOF_MAGICCLOSE |
     79			  WDIOF_KEEPALIVEPING,
     80	.identity	= "EP93xx Watchdog",
     81};
     82
     83static const struct watchdog_ops ep93xx_wdt_ops = {
     84	.owner		= THIS_MODULE,
     85	.start		= ep93xx_wdt_start,
     86	.stop		= ep93xx_wdt_stop,
     87	.ping		= ep93xx_wdt_ping,
     88};
     89
     90static int ep93xx_wdt_probe(struct platform_device *pdev)
     91{
     92	struct device *dev = &pdev->dev;
     93	struct ep93xx_wdt_priv *priv;
     94	struct watchdog_device *wdd;
     95	unsigned long val;
     96	int ret;
     97
     98	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
     99	if (!priv)
    100		return -ENOMEM;
    101
    102	priv->mmio = devm_platform_ioremap_resource(pdev, 0);
    103	if (IS_ERR(priv->mmio))
    104		return PTR_ERR(priv->mmio);
    105
    106	val = readl(priv->mmio + EP93XX_WATCHDOG);
    107
    108	wdd = &priv->wdd;
    109	wdd->bootstatus = (val & 0x01) ? WDIOF_CARDRESET : 0;
    110	wdd->info = &ep93xx_wdt_ident;
    111	wdd->ops = &ep93xx_wdt_ops;
    112	wdd->min_timeout = 1;
    113	wdd->max_hw_heartbeat_ms = 200;
    114	wdd->parent = dev;
    115
    116	watchdog_set_nowayout(wdd, nowayout);
    117
    118	wdd->timeout = WDT_TIMEOUT;
    119	watchdog_init_timeout(wdd, timeout, dev);
    120
    121	watchdog_set_drvdata(wdd, priv);
    122
    123	ret = devm_watchdog_register_device(dev, wdd);
    124	if (ret)
    125		return ret;
    126
    127	dev_info(dev, "EP93XX watchdog driver %s\n",
    128		 (val & 0x08) ? " (nCS1 disable detected)" : "");
    129
    130	return 0;
    131}
    132
    133static struct platform_driver ep93xx_wdt_driver = {
    134	.driver		= {
    135		.name	= "ep93xx-wdt",
    136	},
    137	.probe		= ep93xx_wdt_probe,
    138};
    139
    140module_platform_driver(ep93xx_wdt_driver);
    141
    142MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>");
    143MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
    144MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
    145MODULE_DESCRIPTION("EP93xx Watchdog");
    146MODULE_LICENSE("GPL");