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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Watchdog driver for Cirrus Logic EP93xx family of devices.4 *5 * Copyright (c) 2004 Ray Lehtiniemi6 * Copyright (c) 2006 Tower Technologies7 * Based on ep93xx driver, bits from alim7101_wdt.c8 *9 * Authors: Ray Lehtiniemi <rayl@mail.com>,10 * Alessandro Zummo <a.zummo@towertech.it>11 *12 * Copyright (c) 2012 H Hartley Sweeten <hsweeten@visionengravers.com>13 * Convert to a platform device and use the watchdog framework API14 *15 * This watchdog fires after 250msec, which is a too short interval16 * for us to rely on the user space daemon alone. So we ping the17 * wdt each ~200msec and eventually stop doing it if the user space18 * daemon dies.19 */20 21#include <linux/platform_device.h>22#include <linux/module.h>23#include <linux/watchdog.h>24#include <linux/io.h>25 26/* default timeout (secs) */27#define WDT_TIMEOUT 3028 29static bool nowayout = WATCHDOG_NOWAYOUT;30module_param(nowayout, bool, 0);31MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");32 33static unsigned int timeout;34module_param(timeout, uint, 0);35MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds.");36 37#define EP93XX_WATCHDOG 0x0038#define EP93XX_WDSTATUS 0x0439 40struct ep93xx_wdt_priv {41 void __iomem *mmio;42 struct watchdog_device wdd;43};44 45static int ep93xx_wdt_start(struct watchdog_device *wdd)46{47 struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);48 49 writel(0xaaaa, priv->mmio + EP93XX_WATCHDOG);50 51 return 0;52}53 54static int ep93xx_wdt_stop(struct watchdog_device *wdd)55{56 struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);57 58 writel(0xaa55, priv->mmio + EP93XX_WATCHDOG);59 60 return 0;61}62 63static int ep93xx_wdt_ping(struct watchdog_device *wdd)64{65 struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);66 67 writel(0x5555, priv->mmio + EP93XX_WATCHDOG);68 69 return 0;70}71 72static const struct watchdog_info ep93xx_wdt_ident = {73 .options = WDIOF_CARDRESET |74 WDIOF_SETTIMEOUT |75 WDIOF_MAGICCLOSE |76 WDIOF_KEEPALIVEPING,77 .identity = "EP93xx Watchdog",78};79 80static const struct watchdog_ops ep93xx_wdt_ops = {81 .owner = THIS_MODULE,82 .start = ep93xx_wdt_start,83 .stop = ep93xx_wdt_stop,84 .ping = ep93xx_wdt_ping,85};86 87static int ep93xx_wdt_probe(struct platform_device *pdev)88{89 struct device *dev = &pdev->dev;90 struct ep93xx_wdt_priv *priv;91 struct watchdog_device *wdd;92 unsigned long val;93 int ret;94 95 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);96 if (!priv)97 return -ENOMEM;98 99 priv->mmio = devm_platform_ioremap_resource(pdev, 0);100 if (IS_ERR(priv->mmio))101 return PTR_ERR(priv->mmio);102 103 val = readl(priv->mmio + EP93XX_WATCHDOG);104 105 wdd = &priv->wdd;106 wdd->bootstatus = (val & 0x01) ? WDIOF_CARDRESET : 0;107 wdd->info = &ep93xx_wdt_ident;108 wdd->ops = &ep93xx_wdt_ops;109 wdd->min_timeout = 1;110 wdd->max_hw_heartbeat_ms = 200;111 wdd->parent = dev;112 113 watchdog_set_nowayout(wdd, nowayout);114 115 wdd->timeout = WDT_TIMEOUT;116 watchdog_init_timeout(wdd, timeout, dev);117 118 watchdog_set_drvdata(wdd, priv);119 120 ret = devm_watchdog_register_device(dev, wdd);121 if (ret)122 return ret;123 124 dev_info(dev, "EP93XX watchdog driver %s\n",125 (val & 0x08) ? " (nCS1 disable detected)" : "");126 127 return 0;128}129 130static struct platform_driver ep93xx_wdt_driver = {131 .driver = {132 .name = "ep93xx-wdt",133 },134 .probe = ep93xx_wdt_probe,135};136 137module_platform_driver(ep93xx_wdt_driver);138 139MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>");140MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");141MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");142MODULE_DESCRIPTION("EP93xx Watchdog");143MODULE_LICENSE("GPL");144