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/platform_device.h> 19 #include <linux/watchdog.h> 20 #include <linux/moduleparam.h> 21 22 #define REG_COUNT 0x4 23 #define REG_MODE 0x8 24 #define REG_ENABLE 0xC 25 26 struct moxart_wdt_dev { 27 struct watchdog_device dev; 28 void __iomem *base; 29 unsigned int clock_frequency; 30 }; 31 32 static int heartbeat; 33 34 static int moxart_wdt_restart(struct watchdog_device *wdt_dev, 35 unsigned long action, void *data) 36 { 37 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); 38 39 writel(1, moxart_wdt->base + REG_COUNT); 40 writel(0x5ab9, moxart_wdt->base + REG_MODE); 41 writel(0x03, moxart_wdt->base + REG_ENABLE); 42 43 return 0; 44 } 45 46 static int moxart_wdt_stop(struct watchdog_device *wdt_dev) 47 { 48 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); 49 50 writel(0, moxart_wdt->base + REG_ENABLE); 51 52 return 0; 53 } 54 55 static int moxart_wdt_start(struct watchdog_device *wdt_dev) 56 { 57 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); 58 59 writel(moxart_wdt->clock_frequency * wdt_dev->timeout, 60 moxart_wdt->base + REG_COUNT); 61 writel(0x5ab9, moxart_wdt->base + REG_MODE); 62 writel(0x03, moxart_wdt->base + REG_ENABLE); 63 64 return 0; 65 } 66 67 static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev, 68 unsigned int timeout) 69 { 70 wdt_dev->timeout = timeout; 71 72 return 0; 73 } 74 75 static const struct watchdog_info moxart_wdt_info = { 76 .identity = "moxart-wdt", 77 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | 78 WDIOF_MAGICCLOSE, 79 }; 80 81 static const struct watchdog_ops moxart_wdt_ops = { 82 .owner = THIS_MODULE, 83 .start = moxart_wdt_start, 84 .stop = moxart_wdt_stop, 85 .set_timeout = moxart_wdt_set_timeout, 86 .restart = moxart_wdt_restart, 87 }; 88 89 static int moxart_wdt_probe(struct platform_device *pdev) 90 { 91 struct moxart_wdt_dev *moxart_wdt; 92 struct device *dev = &pdev->dev; 93 struct device_node *node = dev->of_node; 94 struct resource *res; 95 struct clk *clk; 96 int err; 97 unsigned int max_timeout; 98 bool nowayout = WATCHDOG_NOWAYOUT; 99 100 moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL); 101 if (!moxart_wdt) 102 return -ENOMEM; 103 104 platform_set_drvdata(pdev, moxart_wdt); 105 106 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 107 moxart_wdt->base = devm_ioremap_resource(dev, res); 108 if (IS_ERR(moxart_wdt->base)) 109 return PTR_ERR(moxart_wdt->base); 110 111 clk = of_clk_get(node, 0); 112 if (IS_ERR(clk)) { 113 pr_err("%s: of_clk_get failed\n", __func__); 114 return PTR_ERR(clk); 115 } 116 117 moxart_wdt->clock_frequency = clk_get_rate(clk); 118 if (moxart_wdt->clock_frequency == 0) { 119 pr_err("%s: incorrect clock frequency\n", __func__); 120 return -EINVAL; 121 } 122 123 max_timeout = UINT_MAX / moxart_wdt->clock_frequency; 124 125 moxart_wdt->dev.info = &moxart_wdt_info; 126 moxart_wdt->dev.ops = &moxart_wdt_ops; 127 moxart_wdt->dev.timeout = max_timeout; 128 moxart_wdt->dev.min_timeout = 1; 129 moxart_wdt->dev.max_timeout = max_timeout; 130 moxart_wdt->dev.parent = dev; 131 132 watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev); 133 watchdog_set_nowayout(&moxart_wdt->dev, nowayout); 134 watchdog_set_restart_priority(&moxart_wdt->dev, 128); 135 136 watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt); 137 138 err = watchdog_register_device(&moxart_wdt->dev); 139 if (err) 140 return err; 141 142 dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n", 143 moxart_wdt->dev.timeout, nowayout); 144 145 return 0; 146 } 147 148 static int moxart_wdt_remove(struct platform_device *pdev) 149 { 150 struct moxart_wdt_dev *moxart_wdt = platform_get_drvdata(pdev); 151 152 moxart_wdt_stop(&moxart_wdt->dev); 153 154 return 0; 155 } 156 157 static const struct of_device_id moxart_watchdog_match[] = { 158 { .compatible = "moxa,moxart-watchdog" }, 159 { }, 160 }; 161 MODULE_DEVICE_TABLE(of, moxart_watchdog_match); 162 163 static struct platform_driver moxart_wdt_driver = { 164 .probe = moxart_wdt_probe, 165 .remove = moxart_wdt_remove, 166 .driver = { 167 .name = "moxart-watchdog", 168 .of_match_table = moxart_watchdog_match, 169 }, 170 }; 171 module_platform_driver(moxart_wdt_driver); 172 173 module_param(heartbeat, int, 0); 174 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds"); 175 176 MODULE_DESCRIPTION("MOXART watchdog driver"); 177 MODULE_LICENSE("GPL"); 178 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>"); 179