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 #include <asm/system_misc.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 }; 33 34 static struct moxart_wdt_dev *moxart_restart_ctx; 35 36 static int heartbeat; 37 38 static void moxart_wdt_restart(enum reboot_mode reboot_mode, const char *cmd) 39 { 40 writel(1, moxart_restart_ctx->base + REG_COUNT); 41 writel(0x5ab9, moxart_restart_ctx->base + REG_MODE); 42 writel(0x03, moxart_restart_ctx->base + REG_ENABLE); 43 } 44 45 static int moxart_wdt_stop(struct watchdog_device *wdt_dev) 46 { 47 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); 48 49 writel(0, moxart_wdt->base + REG_ENABLE); 50 51 return 0; 52 } 53 54 static int moxart_wdt_start(struct watchdog_device *wdt_dev) 55 { 56 struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); 57 58 writel(moxart_wdt->clock_frequency * wdt_dev->timeout, 59 moxart_wdt->base + REG_COUNT); 60 writel(0x5ab9, moxart_wdt->base + REG_MODE); 61 writel(0x03, moxart_wdt->base + REG_ENABLE); 62 63 return 0; 64 } 65 66 static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev, 67 unsigned int timeout) 68 { 69 wdt_dev->timeout = timeout; 70 71 return 0; 72 } 73 74 static const struct watchdog_info moxart_wdt_info = { 75 .identity = "moxart-wdt", 76 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | 77 WDIOF_MAGICCLOSE, 78 }; 79 80 static const struct watchdog_ops moxart_wdt_ops = { 81 .owner = THIS_MODULE, 82 .start = moxart_wdt_start, 83 .stop = moxart_wdt_stop, 84 .set_timeout = moxart_wdt_set_timeout, 85 }; 86 87 static int moxart_wdt_probe(struct platform_device *pdev) 88 { 89 struct moxart_wdt_dev *moxart_wdt; 90 struct device *dev = &pdev->dev; 91 struct device_node *node = dev->of_node; 92 struct resource *res; 93 struct clk *clk; 94 int err; 95 unsigned int max_timeout; 96 bool nowayout = WATCHDOG_NOWAYOUT; 97 98 moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL); 99 if (!moxart_wdt) 100 return -ENOMEM; 101 102 platform_set_drvdata(pdev, moxart_wdt); 103 104 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 105 moxart_wdt->base = devm_ioremap_resource(dev, res); 106 if (IS_ERR(moxart_wdt->base)) 107 return PTR_ERR(moxart_wdt->base); 108 109 clk = of_clk_get(node, 0); 110 if (IS_ERR(clk)) { 111 pr_err("%s: of_clk_get failed\n", __func__); 112 return PTR_ERR(clk); 113 } 114 115 moxart_wdt->clock_frequency = clk_get_rate(clk); 116 if (moxart_wdt->clock_frequency == 0) { 117 pr_err("%s: incorrect clock frequency\n", __func__); 118 return -EINVAL; 119 } 120 121 max_timeout = UINT_MAX / moxart_wdt->clock_frequency; 122 123 moxart_wdt->dev.info = &moxart_wdt_info; 124 moxart_wdt->dev.ops = &moxart_wdt_ops; 125 moxart_wdt->dev.timeout = max_timeout; 126 moxart_wdt->dev.min_timeout = 1; 127 moxart_wdt->dev.max_timeout = max_timeout; 128 moxart_wdt->dev.parent = dev; 129 130 watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev); 131 watchdog_set_nowayout(&moxart_wdt->dev, nowayout); 132 133 watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt); 134 135 err = watchdog_register_device(&moxart_wdt->dev); 136 if (err) 137 return err; 138 139 moxart_restart_ctx = moxart_wdt; 140 arm_pm_restart = moxart_wdt_restart; 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 arm_pm_restart = NULL; 153 moxart_wdt_stop(&moxart_wdt->dev); 154 watchdog_unregister_device(&moxart_wdt->dev); 155 156 return 0; 157 } 158 159 static const struct of_device_id moxart_watchdog_match[] = { 160 { .compatible = "moxa,moxart-watchdog" }, 161 { }, 162 }; 163 164 static struct platform_driver moxart_wdt_driver = { 165 .probe = moxart_wdt_probe, 166 .remove = moxart_wdt_remove, 167 .driver = { 168 .name = "moxart-watchdog", 169 .owner = THIS_MODULE, 170 .of_match_table = moxart_watchdog_match, 171 }, 172 }; 173 module_platform_driver(moxart_wdt_driver); 174 175 module_param(heartbeat, int, 0); 176 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds"); 177 178 MODULE_DESCRIPTION("MOXART watchdog driver"); 179 MODULE_LICENSE("GPL"); 180 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>"); 181