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 32 static bool nowayout = WATCHDOG_NOWAYOUT; 33 module_param(nowayout, bool, 0); 34 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); 35 36 static unsigned int timeout; 37 module_param(timeout, uint, 0); 38 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds."); 39 40 #define EP93XX_WATCHDOG 0x00 41 #define EP93XX_WDSTATUS 0x04 42 43 struct ep93xx_wdt_priv { 44 void __iomem *mmio; 45 struct watchdog_device wdd; 46 }; 47 48 static 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 57 static 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 66 static 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 75 static 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 83 static 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 90 static 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 } 132 133 static struct platform_driver ep93xx_wdt_driver = { 134 .driver = { 135 .name = "ep93xx-wdt", 136 }, 137 .probe = ep93xx_wdt_probe, 138 }; 139 140 module_platform_driver(ep93xx_wdt_driver); 141 142 MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>"); 143 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); 144 MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>"); 145 MODULE_DESCRIPTION("EP93xx Watchdog"); 146 MODULE_LICENSE("GPL"); 147