1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (c) 2016 Yang Ling <gnaygnil@gmail.com> 4 */ 5 6 #include <linux/clk.h> 7 #include <linux/io.h> 8 #include <linux/module.h> 9 #include <linux/of.h> 10 #include <linux/platform_device.h> 11 #include <linux/watchdog.h> 12 13 /* Loongson 1 Watchdog Register Definitions */ 14 #define WDT_EN 0x0 15 #define WDT_TIMER 0x4 16 #define WDT_SET 0x8 17 18 #define DEFAULT_HEARTBEAT 30 19 20 static bool nowayout = WATCHDOG_NOWAYOUT; 21 module_param(nowayout, bool, 0444); 22 23 static unsigned int heartbeat; 24 module_param(heartbeat, uint, 0444); 25 26 struct ls1x_wdt_drvdata { 27 void __iomem *base; 28 struct clk *clk; 29 unsigned long clk_rate; 30 struct watchdog_device wdt; 31 }; 32 33 static int ls1x_wdt_ping(struct watchdog_device *wdt_dev) 34 { 35 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 36 37 writel(0x1, drvdata->base + WDT_SET); 38 39 return 0; 40 } 41 42 static int ls1x_wdt_set_timeout(struct watchdog_device *wdt_dev, 43 unsigned int timeout) 44 { 45 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 46 unsigned int max_hw_heartbeat = wdt_dev->max_hw_heartbeat_ms / 1000; 47 unsigned int counts; 48 49 wdt_dev->timeout = timeout; 50 51 counts = drvdata->clk_rate * min(timeout, max_hw_heartbeat); 52 writel(counts, drvdata->base + WDT_TIMER); 53 54 return 0; 55 } 56 57 static int ls1x_wdt_start(struct watchdog_device *wdt_dev) 58 { 59 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 60 61 writel(0x1, drvdata->base + WDT_EN); 62 63 return 0; 64 } 65 66 static int ls1x_wdt_stop(struct watchdog_device *wdt_dev) 67 { 68 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 69 70 writel(0x0, drvdata->base + WDT_EN); 71 72 return 0; 73 } 74 75 static int ls1x_wdt_restart(struct watchdog_device *wdt_dev, 76 unsigned long action, void *data) 77 { 78 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 79 80 writel(0x1, drvdata->base + WDT_EN); 81 writel(0x1, drvdata->base + WDT_TIMER); 82 writel(0x1, drvdata->base + WDT_SET); 83 84 return 0; 85 } 86 87 static const struct watchdog_info ls1x_wdt_info = { 88 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 89 .identity = "Loongson1 Watchdog", 90 }; 91 92 static const struct watchdog_ops ls1x_wdt_ops = { 93 .owner = THIS_MODULE, 94 .start = ls1x_wdt_start, 95 .stop = ls1x_wdt_stop, 96 .ping = ls1x_wdt_ping, 97 .set_timeout = ls1x_wdt_set_timeout, 98 .restart = ls1x_wdt_restart, 99 }; 100 101 static int ls1x_wdt_probe(struct platform_device *pdev) 102 { 103 struct device *dev = &pdev->dev; 104 struct ls1x_wdt_drvdata *drvdata; 105 struct watchdog_device *ls1x_wdt; 106 unsigned long clk_rate; 107 int err; 108 109 drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL); 110 if (!drvdata) 111 return -ENOMEM; 112 113 drvdata->base = devm_platform_ioremap_resource(pdev, 0); 114 if (IS_ERR(drvdata->base)) 115 return PTR_ERR(drvdata->base); 116 117 drvdata->clk = devm_clk_get_enabled(dev, NULL); 118 if (IS_ERR(drvdata->clk)) 119 return PTR_ERR(drvdata->clk); 120 121 clk_rate = clk_get_rate(drvdata->clk); 122 if (!clk_rate) 123 return -EINVAL; 124 drvdata->clk_rate = clk_rate; 125 126 ls1x_wdt = &drvdata->wdt; 127 ls1x_wdt->info = &ls1x_wdt_info; 128 ls1x_wdt->ops = &ls1x_wdt_ops; 129 ls1x_wdt->timeout = DEFAULT_HEARTBEAT; 130 ls1x_wdt->min_timeout = 1; 131 ls1x_wdt->max_hw_heartbeat_ms = U32_MAX / clk_rate * 1000; 132 ls1x_wdt->parent = dev; 133 134 watchdog_init_timeout(ls1x_wdt, heartbeat, dev); 135 watchdog_set_nowayout(ls1x_wdt, nowayout); 136 watchdog_set_drvdata(ls1x_wdt, drvdata); 137 138 err = devm_watchdog_register_device(dev, &drvdata->wdt); 139 if (err) 140 return err; 141 142 platform_set_drvdata(pdev, drvdata); 143 144 dev_info(dev, "Loongson1 Watchdog driver registered\n"); 145 146 return 0; 147 } 148 149 #ifdef CONFIG_OF 150 static const struct of_device_id ls1x_wdt_dt_ids[] = { 151 { .compatible = "loongson,ls1b-wdt", }, 152 { .compatible = "loongson,ls1c-wdt", }, 153 { /* sentinel */ } 154 }; 155 MODULE_DEVICE_TABLE(of, ls1x_wdt_dt_ids); 156 #endif 157 158 static struct platform_driver ls1x_wdt_driver = { 159 .probe = ls1x_wdt_probe, 160 .driver = { 161 .name = "ls1x-wdt", 162 .of_match_table = of_match_ptr(ls1x_wdt_dt_ids), 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