1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2016 National Instruments Corp.
4  */
5 
6 #include <linux/acpi.h>
7 #include <linux/bitops.h>
8 #include <linux/device.h>
9 #include <linux/io.h>
10 #include <linux/module.h>
11 #include <linux/platform_device.h>
12 #include <linux/watchdog.h>
13 
14 #define LOCK			0xA5
15 #define UNLOCK			0x5A
16 
17 #define WDT_CTRL_RESET_EN	BIT(7)
18 #define WDT_RELOAD_PORT_EN	BIT(7)
19 
20 #define WDT_CTRL		1
21 #define WDT_RELOAD_CTRL		2
22 #define WDT_PRESET_PRESCALE	4
23 #define WDT_REG_LOCK		5
24 #define WDT_COUNT		6
25 #define WDT_RELOAD_PORT		7
26 
27 #define WDT_MIN_TIMEOUT		1
28 #define WDT_MAX_TIMEOUT		464
29 #define WDT_DEFAULT_TIMEOUT	80
30 
31 #define WDT_MAX_COUNTER		15
32 
33 static unsigned int timeout;
34 module_param(timeout, uint, 0);
35 MODULE_PARM_DESC(timeout,
36 		 "Watchdog timeout in seconds. (default="
37 		 __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
38 
39 static bool nowayout = WATCHDOG_NOWAYOUT;
40 module_param(nowayout, bool, 0);
41 MODULE_PARM_DESC(nowayout,
42 		 "Watchdog cannot be stopped once started. (default="
43 		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
44 
45 struct nic7018_wdt {
46 	u16 io_base;
47 	u32 period;
48 	struct watchdog_device wdd;
49 };
50 
51 struct nic7018_config {
52 	u32 period;
53 	u8 divider;
54 };
55 
56 static const struct nic7018_config nic7018_configs[] = {
57 	{  2, 4 },
58 	{ 32, 5 },
59 };
60 
61 static inline u32 nic7018_timeout(u32 period, u8 counter)
62 {
63 	return period * counter - period / 2;
64 }
65 
66 static const struct nic7018_config *nic7018_get_config(u32 timeout,
67 						       u8 *counter)
68 {
69 	const struct nic7018_config *config;
70 	u8 count;
71 
72 	if (timeout < 30 && timeout != 16) {
73 		config = &nic7018_configs[0];
74 		count = timeout / 2 + 1;
75 	} else {
76 		config = &nic7018_configs[1];
77 		count = DIV_ROUND_UP(timeout + 16, 32);
78 
79 		if (count > WDT_MAX_COUNTER)
80 			count = WDT_MAX_COUNTER;
81 	}
82 	*counter = count;
83 	return config;
84 }
85 
86 static int nic7018_set_timeout(struct watchdog_device *wdd,
87 			       unsigned int timeout)
88 {
89 	struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
90 	const struct nic7018_config *config;
91 	u8 counter;
92 
93 	config = nic7018_get_config(timeout, &counter);
94 
95 	outb(counter << 4 | config->divider,
96 	     wdt->io_base + WDT_PRESET_PRESCALE);
97 
98 	wdd->timeout = nic7018_timeout(config->period, counter);
99 	wdt->period = config->period;
100 
101 	return 0;
102 }
103 
104 static int nic7018_start(struct watchdog_device *wdd)
105 {
106 	struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
107 	u8 control;
108 
109 	nic7018_set_timeout(wdd, wdd->timeout);
110 
111 	control = inb(wdt->io_base + WDT_RELOAD_CTRL);
112 	outb(control | WDT_RELOAD_PORT_EN, wdt->io_base + WDT_RELOAD_CTRL);
113 
114 	outb(1, wdt->io_base + WDT_RELOAD_PORT);
115 
116 	control = inb(wdt->io_base + WDT_CTRL);
117 	outb(control | WDT_CTRL_RESET_EN, wdt->io_base + WDT_CTRL);
118 
119 	return 0;
120 }
121 
122 static int nic7018_stop(struct watchdog_device *wdd)
123 {
124 	struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
125 
126 	outb(0, wdt->io_base + WDT_CTRL);
127 	outb(0, wdt->io_base + WDT_RELOAD_CTRL);
128 	outb(0xF0, wdt->io_base + WDT_PRESET_PRESCALE);
129 
130 	return 0;
131 }
132 
133 static int nic7018_ping(struct watchdog_device *wdd)
134 {
135 	struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
136 
137 	outb(1, wdt->io_base + WDT_RELOAD_PORT);
138 
139 	return 0;
140 }
141 
142 static unsigned int nic7018_get_timeleft(struct watchdog_device *wdd)
143 {
144 	struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
145 	u8 count;
146 
147 	count = inb(wdt->io_base + WDT_COUNT) & 0xF;
148 	if (!count)
149 		return 0;
150 
151 	return nic7018_timeout(wdt->period, count);
152 }
153 
154 static const struct watchdog_info nic7018_wdd_info = {
155 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
156 	.identity = "NIC7018 Watchdog",
157 };
158 
159 static const struct watchdog_ops nic7018_wdd_ops = {
160 	.owner = THIS_MODULE,
161 	.start = nic7018_start,
162 	.stop = nic7018_stop,
163 	.ping = nic7018_ping,
164 	.set_timeout = nic7018_set_timeout,
165 	.get_timeleft = nic7018_get_timeleft,
166 };
167 
168 static int nic7018_probe(struct platform_device *pdev)
169 {
170 	struct device *dev = &pdev->dev;
171 	struct watchdog_device *wdd;
172 	struct nic7018_wdt *wdt;
173 	struct resource *io_rc;
174 	int ret;
175 
176 	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
177 	if (!wdt)
178 		return -ENOMEM;
179 
180 	platform_set_drvdata(pdev, wdt);
181 
182 	io_rc = platform_get_resource(pdev, IORESOURCE_IO, 0);
183 	if (!io_rc) {
184 		dev_err(dev, "missing IO resources\n");
185 		return -EINVAL;
186 	}
187 
188 	if (!devm_request_region(dev, io_rc->start, resource_size(io_rc),
189 				 KBUILD_MODNAME)) {
190 		dev_err(dev, "failed to get IO region\n");
191 		return -EBUSY;
192 	}
193 
194 	wdt->io_base = io_rc->start;
195 	wdd = &wdt->wdd;
196 	wdd->info = &nic7018_wdd_info;
197 	wdd->ops = &nic7018_wdd_ops;
198 	wdd->min_timeout = WDT_MIN_TIMEOUT;
199 	wdd->max_timeout = WDT_MAX_TIMEOUT;
200 	wdd->timeout = WDT_DEFAULT_TIMEOUT;
201 	wdd->parent = dev;
202 
203 	watchdog_set_drvdata(wdd, wdt);
204 	watchdog_set_nowayout(wdd, nowayout);
205 	watchdog_init_timeout(wdd, timeout, dev);
206 
207 	/* Unlock WDT register */
208 	outb(UNLOCK, wdt->io_base + WDT_REG_LOCK);
209 
210 	ret = watchdog_register_device(wdd);
211 	if (ret) {
212 		outb(LOCK, wdt->io_base + WDT_REG_LOCK);
213 		return ret;
214 	}
215 
216 	dev_dbg(dev, "io_base=0x%04X, timeout=%d, nowayout=%d\n",
217 		wdt->io_base, timeout, nowayout);
218 	return 0;
219 }
220 
221 static int nic7018_remove(struct platform_device *pdev)
222 {
223 	struct nic7018_wdt *wdt = platform_get_drvdata(pdev);
224 
225 	watchdog_unregister_device(&wdt->wdd);
226 
227 	/* Lock WDT register */
228 	outb(LOCK, wdt->io_base + WDT_REG_LOCK);
229 
230 	return 0;
231 }
232 
233 static const struct acpi_device_id nic7018_device_ids[] = {
234 	{"NIC7018", 0},
235 	{"", 0},
236 };
237 MODULE_DEVICE_TABLE(acpi, nic7018_device_ids);
238 
239 static struct platform_driver watchdog_driver = {
240 	.probe = nic7018_probe,
241 	.remove = nic7018_remove,
242 	.driver = {
243 		.name = KBUILD_MODNAME,
244 		.acpi_match_table = ACPI_PTR(nic7018_device_ids),
245 	},
246 };
247 
248 module_platform_driver(watchdog_driver);
249 
250 MODULE_DESCRIPTION("National Instruments NIC7018 Watchdog driver");
251 MODULE_AUTHOR("Hui Chun Ong <hui.chun.ong@ni.com>");
252 MODULE_LICENSE("GPL");
253