1 /* 2 * MOXA ART SoCs watchdog driver. 3 * 4 * Copyright (C) 2013 Jonas Jensen 5 * 6 * Jonas Jensen <jonas.jensen@gmail.com> 7 * 8 * This file is licensed under the terms of the GNU General Public 9 * License version 2. This program is licensed "as is" without any 10 * warranty of any kind, whether express or implied. 11 */ 12 13 #include <linux/clk.h> 14 #include <linux/io.h> 15 #include <linux/module.h> 16 #include <linux/err.h> 17 #include <linux/kernel.h> 18 #include <linux/notifier.h> 19 #include <linux/platform_device.h> 20 #include <linux/reboot.h> 21 #include <linux/watchdog.h> 22 #include <linux/moduleparam.h> 23 24 #define REG_COUNT 0x4 25 #define REG_MODE 0x8 26 #define REG_ENABLE 0xC 27 28 struct moxart_wdt_dev { 29 struct watchdog_device dev; 30 void __iomem *base; 31 unsigned int clock_frequency; 32 struct notifier_block restart_handler; 33 }; 34 35 static int heartbeat; 36 37 static int moxart_restart_handle(struct notifier_block *this, 38 unsigned long mode, void *cmd) 39 { 40 struct moxart_wdt_dev *moxart_wdt = container_of(this, 41 struct moxart_wdt_dev, 42 restart_handler); 43 writel(1, moxart_wdt->base + REG_COUNT); 44 writel(0x5ab9, moxart_wdt->base + REG_MODE); 45 writel(0x03, moxart_wdt->base + REG_ENABLE); 46 47 return NOTIFY_DONE; 48 } 49 50 static int moxart_wdt_stop(struct watchdog_device *wdt_dev) 51 { 52 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); 53 54 writel(0, moxart_wdt->base + REG_ENABLE); 55 56 return 0; 57 } 58 59 static int moxart_wdt_start(struct watchdog_device *wdt_dev) 60 { 61 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); 62 63 writel(moxart_wdt->clock_frequency * wdt_dev->timeout, 64 moxart_wdt->base + REG_COUNT); 65 writel(0x5ab9, moxart_wdt->base + REG_MODE); 66 writel(0x03, moxart_wdt->base + REG_ENABLE); 67 68 return 0; 69 } 70 71 static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev, 72 unsigned int timeout) 73 { 74 wdt_dev->timeout = timeout; 75 76 return 0; 77 } 78 79 static const struct watchdog_info moxart_wdt_info = { 80 .identity = "moxart-wdt", 81 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | 82 WDIOF_MAGICCLOSE, 83 }; 84 85 static const struct watchdog_ops moxart_wdt_ops = { 86 .owner = THIS_MODULE, 87 .start = moxart_wdt_start, 88 .stop = moxart_wdt_stop, 89 .set_timeout = moxart_wdt_set_timeout, 90 }; 91 92 static int moxart_wdt_probe(struct platform_device *pdev) 93 { 94 struct moxart_wdt_dev *moxart_wdt; 95 struct device *dev = &pdev->dev; 96 struct device_node *node = dev->of_node; 97 struct resource *res; 98 struct clk *clk; 99 int err; 100 unsigned int max_timeout; 101 bool nowayout = WATCHDOG_NOWAYOUT; 102 103 moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL); 104 if (!moxart_wdt) 105 return -ENOMEM; 106 107 platform_set_drvdata(pdev, moxart_wdt); 108 109 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 110 moxart_wdt->base = devm_ioremap_resource(dev, res); 111 if (IS_ERR(moxart_wdt->base)) 112 return PTR_ERR(moxart_wdt->base); 113 114 clk = of_clk_get(node, 0); 115 if (IS_ERR(clk)) { 116 pr_err("%s: of_clk_get failed\n", __func__); 117 return PTR_ERR(clk); 118 } 119 120 moxart_wdt->clock_frequency = clk_get_rate(clk); 121 if (moxart_wdt->clock_frequency == 0) { 122 pr_err("%s: incorrect clock frequency\n", __func__); 123 return -EINVAL; 124 } 125 126 max_timeout = UINT_MAX / moxart_wdt->clock_frequency; 127 128 moxart_wdt->dev.info = &moxart_wdt_info; 129 moxart_wdt->dev.ops = &moxart_wdt_ops; 130 moxart_wdt->dev.timeout = max_timeout; 131 moxart_wdt->dev.min_timeout = 1; 132 moxart_wdt->dev.max_timeout = max_timeout; 133 moxart_wdt->dev.parent = dev; 134 135 watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev); 136 watchdog_set_nowayout(&moxart_wdt->dev, nowayout); 137 138 watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt); 139 140 err = watchdog_register_device(&moxart_wdt->dev); 141 if (err) 142 return err; 143 144 moxart_wdt->restart_handler.notifier_call = moxart_restart_handle; 145 moxart_wdt->restart_handler.priority = 128; 146 err = register_restart_handler(&moxart_wdt->restart_handler); 147 if (err) 148 dev_err(dev, "cannot register restart notifier (err=%d)\n", 149 err); 150 151 dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n", 152 moxart_wdt->dev.timeout, nowayout); 153 154 return 0; 155 } 156 157 static int moxart_wdt_remove(struct platform_device *pdev) 158 { 159 struct moxart_wdt_dev *moxart_wdt = platform_get_drvdata(pdev); 160 161 unregister_restart_handler(&moxart_wdt->restart_handler); 162 moxart_wdt_stop(&moxart_wdt->dev); 163 164 return 0; 165 } 166 167 static const struct of_device_id moxart_watchdog_match[] = { 168 { .compatible = "moxa,moxart-watchdog" }, 169 { }, 170 }; 171 172 static struct platform_driver moxart_wdt_driver = { 173 .probe = moxart_wdt_probe, 174 .remove = moxart_wdt_remove, 175 .driver = { 176 .name = "moxart-watchdog", 177 .of_match_table = moxart_watchdog_match, 178 }, 179 }; 180 module_platform_driver(moxart_wdt_driver); 181 182 module_param(heartbeat, int, 0); 183 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds"); 184 185 MODULE_DESCRIPTION("MOXART watchdog driver"); 186 MODULE_LICENSE("GPL"); 187 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>"); 188