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
nic7018_timeout(u32 period,u8 counter)61 static inline u32 nic7018_timeout(u32 period, u8 counter)
62 {
63 return period * counter - period / 2;
64 }
65
nic7018_get_config(u32 timeout,u8 * counter)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
nic7018_set_timeout(struct watchdog_device * wdd,unsigned int timeout)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
nic7018_start(struct watchdog_device * wdd)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
nic7018_stop(struct watchdog_device * wdd)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
nic7018_ping(struct watchdog_device * wdd)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
nic7018_get_timeleft(struct watchdog_device * wdd)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
nic7018_probe(struct platform_device * pdev)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
nic7018_remove(struct platform_device * pdev)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