1 /* 2 * Copyright (c) 2016 Yang Ling <gnaygnil@gmail.com> 3 * 4 * This program is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License as published by the 6 * Free Software Foundation; either version 2 of the License, or (at your 7 * option) any later version. 8 */ 9 10 #include <linux/clk.h> 11 #include <linux/module.h> 12 #include <linux/platform_device.h> 13 #include <linux/watchdog.h> 14 #include <loongson1.h> 15 16 #define DEFAULT_HEARTBEAT 30 17 18 static bool nowayout = WATCHDOG_NOWAYOUT; 19 module_param(nowayout, bool, 0444); 20 21 static unsigned int heartbeat; 22 module_param(heartbeat, uint, 0444); 23 24 struct ls1x_wdt_drvdata { 25 void __iomem *base; 26 struct clk *clk; 27 unsigned long clk_rate; 28 struct watchdog_device wdt; 29 }; 30 31 static int ls1x_wdt_ping(struct watchdog_device *wdt_dev) 32 { 33 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 34 35 writel(0x1, drvdata->base + WDT_SET); 36 37 return 0; 38 } 39 40 static int ls1x_wdt_set_timeout(struct watchdog_device *wdt_dev, 41 unsigned int timeout) 42 { 43 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 44 unsigned int max_hw_heartbeat = wdt_dev->max_hw_heartbeat_ms / 1000; 45 unsigned int counts; 46 47 wdt_dev->timeout = timeout; 48 49 counts = drvdata->clk_rate * min(timeout, max_hw_heartbeat); 50 writel(counts, drvdata->base + WDT_TIMER); 51 52 return 0; 53 } 54 55 static int ls1x_wdt_start(struct watchdog_device *wdt_dev) 56 { 57 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 58 59 writel(0x1, drvdata->base + WDT_EN); 60 61 return 0; 62 } 63 64 static int ls1x_wdt_stop(struct watchdog_device *wdt_dev) 65 { 66 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 67 68 writel(0x0, drvdata->base + WDT_EN); 69 70 return 0; 71 } 72 73 static const struct watchdog_info ls1x_wdt_info = { 74 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 75 .identity = "Loongson1 Watchdog", 76 }; 77 78 static const struct watchdog_ops ls1x_wdt_ops = { 79 .owner = THIS_MODULE, 80 .start = ls1x_wdt_start, 81 .stop = ls1x_wdt_stop, 82 .ping = ls1x_wdt_ping, 83 .set_timeout = ls1x_wdt_set_timeout, 84 }; 85 86 static int ls1x_wdt_probe(struct platform_device *pdev) 87 { 88 struct ls1x_wdt_drvdata *drvdata; 89 struct watchdog_device *ls1x_wdt; 90 unsigned long clk_rate; 91 struct resource *res; 92 int err; 93 94 drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL); 95 if (!drvdata) 96 return -ENOMEM; 97 98 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 99 drvdata->base = devm_ioremap_resource(&pdev->dev, res); 100 if (IS_ERR(drvdata->base)) 101 return PTR_ERR(drvdata->base); 102 103 drvdata->clk = devm_clk_get(&pdev->dev, pdev->name); 104 if (IS_ERR(drvdata->clk)) 105 return PTR_ERR(drvdata->clk); 106 107 err = clk_prepare_enable(drvdata->clk); 108 if (err) { 109 dev_err(&pdev->dev, "clk enable failed\n"); 110 return err; 111 } 112 113 clk_rate = clk_get_rate(drvdata->clk); 114 if (!clk_rate) { 115 err = -EINVAL; 116 goto err0; 117 } 118 drvdata->clk_rate = clk_rate; 119 120 ls1x_wdt = &drvdata->wdt; 121 ls1x_wdt->info = &ls1x_wdt_info; 122 ls1x_wdt->ops = &ls1x_wdt_ops; 123 ls1x_wdt->timeout = DEFAULT_HEARTBEAT; 124 ls1x_wdt->min_timeout = 1; 125 ls1x_wdt->max_hw_heartbeat_ms = U32_MAX / clk_rate * 1000; 126 ls1x_wdt->parent = &pdev->dev; 127 128 watchdog_init_timeout(ls1x_wdt, heartbeat, &pdev->dev); 129 watchdog_set_nowayout(ls1x_wdt, nowayout); 130 watchdog_set_drvdata(ls1x_wdt, drvdata); 131 132 err = watchdog_register_device(&drvdata->wdt); 133 if (err) { 134 dev_err(&pdev->dev, "failed to register watchdog device\n"); 135 goto err0; 136 } 137 138 platform_set_drvdata(pdev, drvdata); 139 140 dev_info(&pdev->dev, "Loongson1 Watchdog driver registered\n"); 141 142 return 0; 143 err0: 144 clk_disable_unprepare(drvdata->clk); 145 return err; 146 } 147 148 static int ls1x_wdt_remove(struct platform_device *pdev) 149 { 150 struct ls1x_wdt_drvdata *drvdata = platform_get_drvdata(pdev); 151 152 watchdog_unregister_device(&drvdata->wdt); 153 clk_disable_unprepare(drvdata->clk); 154 155 return 0; 156 } 157 158 static struct platform_driver ls1x_wdt_driver = { 159 .probe = ls1x_wdt_probe, 160 .remove = ls1x_wdt_remove, 161 .driver = { 162 .name = "ls1x-wdt", 163 }, 164 }; 165 166 module_platform_driver(ls1x_wdt_driver); 167 168 MODULE_AUTHOR("Yang Ling <gnaygnil@gmail.com>"); 169 MODULE_DESCRIPTION("Loongson1 Watchdog Driver"); 170 MODULE_LICENSE("GPL"); 171