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