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
ls1x_wdt_ping(struct watchdog_device * wdt_dev)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
ls1x_wdt_set_timeout(struct watchdog_device * wdt_dev,unsigned int timeout)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
ls1x_wdt_start(struct watchdog_device * wdt_dev)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
ls1x_wdt_stop(struct watchdog_device * wdt_dev)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
ls1x_wdt_restart(struct watchdog_device * wdt_dev,unsigned long action,void * data)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
ls1x_wdt_probe(struct platform_device * pdev)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