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/module.h> 8 #include <linux/of.h> 9 #include <linux/platform_device.h> 10 #include <linux/watchdog.h> 11 12 /* Loongson 1 Watchdog Register Definitions */ 13 #define WDT_EN 0x0 14 #define WDT_TIMER 0x4 15 #define WDT_SET 0x8 16 17 #define DEFAULT_HEARTBEAT 30 18 19 static bool nowayout = WATCHDOG_NOWAYOUT; 20 module_param(nowayout, bool, 0444); 21 22 static unsigned int heartbeat; 23 module_param(heartbeat, uint, 0444); 24 25 struct ls1x_wdt_drvdata { 26 void __iomem *base; 27 struct clk *clk; 28 unsigned long clk_rate; 29 struct watchdog_device wdt; 30 }; 31 32 static int ls1x_wdt_ping(struct watchdog_device *wdt_dev) 33 { 34 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 35 36 writel(0x1, drvdata->base + WDT_SET); 37 38 return 0; 39 } 40 41 static int ls1x_wdt_set_timeout(struct watchdog_device *wdt_dev, 42 unsigned int timeout) 43 { 44 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 45 unsigned int max_hw_heartbeat = wdt_dev->max_hw_heartbeat_ms / 1000; 46 unsigned int counts; 47 48 wdt_dev->timeout = timeout; 49 50 counts = drvdata->clk_rate * min(timeout, max_hw_heartbeat); 51 writel(counts, drvdata->base + WDT_TIMER); 52 53 return 0; 54 } 55 56 static int ls1x_wdt_start(struct watchdog_device *wdt_dev) 57 { 58 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 59 60 writel(0x1, drvdata->base + WDT_EN); 61 62 return 0; 63 } 64 65 static int ls1x_wdt_stop(struct watchdog_device *wdt_dev) 66 { 67 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 68 69 writel(0x0, drvdata->base + WDT_EN); 70 71 return 0; 72 } 73 74 static int ls1x_wdt_restart(struct watchdog_device *wdt_dev, 75 unsigned long action, void *data) 76 { 77 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev); 78 79 writel(0x1, drvdata->base + WDT_EN); 80 writel(0x1, drvdata->base + WDT_TIMER); 81 writel(0x1, drvdata->base + WDT_SET); 82 83 return 0; 84 } 85 86 static const struct watchdog_info ls1x_wdt_info = { 87 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 88 .identity = "Loongson1 Watchdog", 89 }; 90 91 static const struct watchdog_ops ls1x_wdt_ops = { 92 .owner = THIS_MODULE, 93 .start = ls1x_wdt_start, 94 .stop = ls1x_wdt_stop, 95 .ping = ls1x_wdt_ping, 96 .set_timeout = ls1x_wdt_set_timeout, 97 .restart = ls1x_wdt_restart, 98 }; 99 100 static int ls1x_wdt_probe(struct platform_device *pdev) 101 { 102 struct device *dev = &pdev->dev; 103 struct ls1x_wdt_drvdata *drvdata; 104 struct watchdog_device *ls1x_wdt; 105 unsigned long clk_rate; 106 int err; 107 108 drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL); 109 if (!drvdata) 110 return -ENOMEM; 111 112 drvdata->base = devm_platform_ioremap_resource(pdev, 0); 113 if (IS_ERR(drvdata->base)) 114 return PTR_ERR(drvdata->base); 115 116 drvdata->clk = devm_clk_get_enabled(dev, NULL); 117 if (IS_ERR(drvdata->clk)) 118 return PTR_ERR(drvdata->clk); 119 120 clk_rate = clk_get_rate(drvdata->clk); 121 if (!clk_rate) 122 return -EINVAL; 123 drvdata->clk_rate = clk_rate; 124 125 ls1x_wdt = &drvdata->wdt; 126 ls1x_wdt->info = &ls1x_wdt_info; 127 ls1x_wdt->ops = &ls1x_wdt_ops; 128 ls1x_wdt->timeout = DEFAULT_HEARTBEAT; 129 ls1x_wdt->min_timeout = 1; 130 ls1x_wdt->max_hw_heartbeat_ms = U32_MAX / clk_rate * 1000; 131 ls1x_wdt->parent = dev; 132 133 watchdog_init_timeout(ls1x_wdt, heartbeat, dev); 134 watchdog_set_nowayout(ls1x_wdt, nowayout); 135 watchdog_set_drvdata(ls1x_wdt, drvdata); 136 137 err = devm_watchdog_register_device(dev, &drvdata->wdt); 138 if (err) 139 return err; 140 141 platform_set_drvdata(pdev, drvdata); 142 143 dev_info(dev, "Loongson1 Watchdog driver registered\n"); 144 145 return 0; 146 } 147 148 #ifdef CONFIG_OF 149 static const struct of_device_id ls1x_wdt_dt_ids[] = { 150 { .compatible = "loongson,ls1b-wdt", }, 151 { .compatible = "loongson,ls1c-wdt", }, 152 { /* sentinel */ } 153 }; 154 MODULE_DEVICE_TABLE(of, ls1x_wdt_dt_ids); 155 #endif 156 157 static struct platform_driver ls1x_wdt_driver = { 158 .probe = ls1x_wdt_probe, 159 .driver = { 160 .name = "ls1x-wdt", 161 .of_match_table = of_match_ptr(ls1x_wdt_dt_ids), 162 }, 163 }; 164 165 module_platform_driver(ls1x_wdt_driver); 166 167 MODULE_AUTHOR("Yang Ling <gnaygnil@gmail.com>"); 168 MODULE_DESCRIPTION("Loongson1 Watchdog Driver"); 169 MODULE_LICENSE("GPL"); 170