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