1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2016 Yang Ling <gnaygnil@gmail.com>
4 * Copyright (C) 2025 Binbin Zhou <zhoubinbin@loongson.cn>
5 */
6
7 #include <linux/clk.h>
8 #include <linux/io.h>
9 #include <linux/module.h>
10 #include <linux/of.h>
11 #include <linux/platform_device.h>
12 #include <linux/watchdog.h>
13
14 /* Loongson Watchdog Register Definitions */
15 #define WDT_EN 0x0
16
17 #define DEFAULT_HEARTBEAT 30
18
19 static bool nowayout = WATCHDOG_NOWAYOUT;
20 module_param(nowayout, bool, 0);
21 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
22 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
23
24 static unsigned int heartbeat;
25 module_param(heartbeat, uint, 0);
26 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (default="
27 __MODULE_STRING(DEFAULT_HEARTBEAT) ")");
28
29 struct ls1x_wdt_pdata {
30 u32 timer_offset;
31 u32 set_offset;
32 u32 wdt_en_bit;
33 };
34
35 static const struct ls1x_wdt_pdata ls1b_wdt_pdata = {
36 .timer_offset = 0x4,
37 .set_offset = 0x8,
38 .wdt_en_bit = BIT(0),
39 };
40
41 static const struct ls1x_wdt_pdata ls2k0300_wdt_pdata = {
42 .timer_offset = 0x8,
43 .set_offset = 0x4,
44 .wdt_en_bit = BIT(1),
45 };
46
47 struct ls1x_wdt_drvdata {
48 void __iomem *base;
49 struct clk *clk;
50 unsigned long clk_rate;
51 struct watchdog_device wdt;
52 const struct ls1x_wdt_pdata *pdata;
53 };
54
ls1x_wdt_ping(struct watchdog_device * wdt_dev)55 static int ls1x_wdt_ping(struct watchdog_device *wdt_dev)
56 {
57 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
58
59 writel(0x1, drvdata->base + drvdata->pdata->set_offset);
60
61 return 0;
62 }
63
ls1x_wdt_set_timeout(struct watchdog_device * wdt_dev,unsigned int timeout)64 static int ls1x_wdt_set_timeout(struct watchdog_device *wdt_dev,
65 unsigned int timeout)
66 {
67 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
68 unsigned int max_hw_heartbeat = wdt_dev->max_hw_heartbeat_ms / 1000;
69 unsigned int counts;
70
71 wdt_dev->timeout = timeout;
72
73 counts = drvdata->clk_rate * min(timeout, max_hw_heartbeat);
74 writel(counts, drvdata->base + drvdata->pdata->timer_offset);
75
76 return 0;
77 }
78
ls1x_wdt_start(struct watchdog_device * wdt_dev)79 static int ls1x_wdt_start(struct watchdog_device *wdt_dev)
80 {
81 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
82
83 writel(drvdata->pdata->wdt_en_bit, drvdata->base + WDT_EN);
84
85 return 0;
86 }
87
ls1x_wdt_stop(struct watchdog_device * wdt_dev)88 static int ls1x_wdt_stop(struct watchdog_device *wdt_dev)
89 {
90 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
91 u32 val = readl(drvdata->base + WDT_EN);
92
93 val &= ~(drvdata->pdata->wdt_en_bit);
94 writel(val, drvdata->base + WDT_EN);
95
96 return 0;
97 }
98
ls1x_wdt_restart(struct watchdog_device * wdt_dev,unsigned long action,void * data)99 static int ls1x_wdt_restart(struct watchdog_device *wdt_dev,
100 unsigned long action, void *data)
101 {
102 struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
103
104 writel(drvdata->pdata->wdt_en_bit, drvdata->base + WDT_EN);
105 writel(0x1, drvdata->base + drvdata->pdata->timer_offset);
106 writel(0x1, drvdata->base + drvdata->pdata->set_offset);
107
108 return 0;
109 }
110
111 static const struct watchdog_info ls1x_wdt_info = {
112 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
113 .identity = "Loongson1 Watchdog",
114 };
115
116 static const struct watchdog_ops ls1x_wdt_ops = {
117 .owner = THIS_MODULE,
118 .start = ls1x_wdt_start,
119 .stop = ls1x_wdt_stop,
120 .ping = ls1x_wdt_ping,
121 .set_timeout = ls1x_wdt_set_timeout,
122 .restart = ls1x_wdt_restart,
123 };
124
ls1x_wdt_probe(struct platform_device * pdev)125 static int ls1x_wdt_probe(struct platform_device *pdev)
126 {
127 struct device *dev = &pdev->dev;
128 struct ls1x_wdt_drvdata *drvdata;
129 struct watchdog_device *ls1x_wdt;
130 unsigned long clk_rate;
131
132 drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
133 if (!drvdata)
134 return -ENOMEM;
135 platform_set_drvdata(pdev, drvdata);
136
137 drvdata->pdata = of_device_get_match_data(dev);
138
139 drvdata->base = devm_platform_ioremap_resource(pdev, 0);
140 if (IS_ERR(drvdata->base))
141 return PTR_ERR(drvdata->base);
142
143 drvdata->clk = devm_clk_get_enabled(dev, NULL);
144 if (IS_ERR(drvdata->clk))
145 return PTR_ERR(drvdata->clk);
146
147 clk_rate = clk_get_rate(drvdata->clk);
148 if (!clk_rate)
149 return -EINVAL;
150 drvdata->clk_rate = clk_rate;
151
152 ls1x_wdt = &drvdata->wdt;
153 ls1x_wdt->info = &ls1x_wdt_info;
154 ls1x_wdt->ops = &ls1x_wdt_ops;
155 ls1x_wdt->timeout = DEFAULT_HEARTBEAT;
156 ls1x_wdt->min_timeout = 1;
157 ls1x_wdt->max_hw_heartbeat_ms = U32_MAX / clk_rate * 1000;
158 ls1x_wdt->parent = dev;
159
160 watchdog_init_timeout(ls1x_wdt, heartbeat, dev);
161 watchdog_set_nowayout(ls1x_wdt, nowayout);
162 watchdog_set_drvdata(ls1x_wdt, drvdata);
163
164 return devm_watchdog_register_device(dev, &drvdata->wdt);
165 }
166
ls1x_wdt_resume(struct device * dev)167 static int ls1x_wdt_resume(struct device *dev)
168 {
169 struct ls1x_wdt_drvdata *data = dev_get_drvdata(dev);
170
171 if (watchdog_active(&data->wdt))
172 ls1x_wdt_start(&data->wdt);
173
174 return 0;
175 }
176
ls1x_wdt_suspend(struct device * dev)177 static int ls1x_wdt_suspend(struct device *dev)
178 {
179 struct ls1x_wdt_drvdata *data = dev_get_drvdata(dev);
180
181 if (watchdog_active(&data->wdt))
182 ls1x_wdt_stop(&data->wdt);
183
184 return 0;
185 }
186
187 static DEFINE_SIMPLE_DEV_PM_OPS(ls1x_wdt_pm_ops, ls1x_wdt_suspend, ls1x_wdt_resume);
188
189 static const struct of_device_id ls1x_wdt_dt_ids[] = {
190 { .compatible = "loongson,ls1b-wdt", .data = &ls1b_wdt_pdata },
191 { .compatible = "loongson,ls1c-wdt", .data = &ls1b_wdt_pdata },
192 { .compatible = "loongson,ls2k0300-wdt", .data = &ls2k0300_wdt_pdata },
193 { /* sentinel */ }
194 };
195 MODULE_DEVICE_TABLE(of, ls1x_wdt_dt_ids);
196
197 static struct platform_driver ls1x_wdt_driver = {
198 .probe = ls1x_wdt_probe,
199 .driver = {
200 .name = "ls1x-wdt",
201 .of_match_table = ls1x_wdt_dt_ids,
202 .pm = pm_ptr(&ls1x_wdt_pm_ops),
203 },
204 };
205
206 module_platform_driver(ls1x_wdt_driver);
207
208 MODULE_AUTHOR("Yang Ling <gnaygnil@gmail.com>");
209 MODULE_AUTHOR("Binbin Zhou <zhoubinbin@loongson.cn>");
210 MODULE_DESCRIPTION("Loongson Watchdog Driver");
211 MODULE_LICENSE("GPL");
212