1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Watchdog Timer Driver
4 * for ITE IT87xx Environment Control - Low Pin Count Input / Output
5 *
6 * (c) Copyright 2007 Oliver Schuster <olivers137@aol.com>
7 *
8 * Based on softdog.c by Alan Cox,
9 * 83977f_wdt.c by Jose Goncalves,
10 * it87.c by Chris Gauthron, Jean Delvare
11 *
12 * Data-sheets: Publicly available at the ITE website
13 * http://www.ite.com.tw/
14 *
15 * Support of the watchdog timers, which are available on
16 * IT8607, IT8620, IT8622, IT8625, IT8628, IT8655, IT8665, IT8686,
17 * IT8702, IT8712, IT8716, IT8718, IT8720, IT8721, IT8726, IT8728,
18 * and IT8783.
19 */
20
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22
23 #include <linux/init.h>
24 #include <linux/io.h>
25 #include <linux/kernel.h>
26 #include <linux/module.h>
27 #include <linux/moduleparam.h>
28 #include <linux/types.h>
29 #include <linux/watchdog.h>
30
31 #define WATCHDOG_NAME "IT87 WDT"
32
33 /* Defaults for Module Parameter */
34 #define DEFAULT_TIMEOUT 60
35 #define DEFAULT_TESTMODE 0
36 #define DEFAULT_NOWAYOUT WATCHDOG_NOWAYOUT
37
38 /* IO Ports */
39 #define REG 0x2e
40 #define VAL 0x2f
41
42 /* Logical device Numbers LDN */
43 #define GPIO 0x07
44
45 /* Configuration Registers and Functions */
46 #define LDNREG 0x07
47 #define CHIPID 0x20
48 #define CHIPREV 0x22
49
50 /* Chip Id numbers */
51 #define NO_DEV_ID 0xffff
52 #define IT8607_ID 0x8607
53 #define IT8620_ID 0x8620
54 #define IT8622_ID 0x8622
55 #define IT8625_ID 0x8625
56 #define IT8628_ID 0x8628
57 #define IT8655_ID 0x8655
58 #define IT8665_ID 0x8665
59 #define IT8686_ID 0x8686
60 #define IT8702_ID 0x8702
61 #define IT8705_ID 0x8705
62 #define IT8712_ID 0x8712
63 #define IT8716_ID 0x8716
64 #define IT8718_ID 0x8718
65 #define IT8720_ID 0x8720
66 #define IT8721_ID 0x8721
67 #define IT8726_ID 0x8726 /* the data sheet suggest wrongly 0x8716 */
68 #define IT8728_ID 0x8728
69 #define IT8783_ID 0x8783
70
71 /* GPIO Configuration Registers LDN=0x07 */
72 #define WDTCTRL 0x71
73 #define WDTCFG 0x72
74 #define WDTVALLSB 0x73
75 #define WDTVALMSB 0x74
76
77 /* GPIO Bits WDTCFG */
78 #define WDT_TOV1 0x80
79 #define WDT_KRST 0x40
80 #define WDT_TOVE 0x20
81 #define WDT_PWROK 0x10 /* not in it8721 */
82 #define WDT_INT_MASK 0x0f
83
84 static unsigned int max_units, chip_type;
85
86 static unsigned int timeout = DEFAULT_TIMEOUT;
87 static int testmode = DEFAULT_TESTMODE;
88 static bool nowayout = DEFAULT_NOWAYOUT;
89
90 module_param(timeout, int, 0);
91 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default="
92 __MODULE_STRING(DEFAULT_TIMEOUT));
93 module_param(testmode, int, 0);
94 MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default="
95 __MODULE_STRING(DEFAULT_TESTMODE));
96 module_param(nowayout, bool, 0);
97 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
98 __MODULE_STRING(WATCHDOG_NOWAYOUT));
99
100 /* Superio Chip */
101
superio_enter(void)102 static inline int superio_enter(void)
103 {
104 /*
105 * Try to reserve REG and REG + 1 for exclusive access.
106 */
107 if (!request_muxed_region(REG, 2, WATCHDOG_NAME))
108 return -EBUSY;
109
110 outb(0x87, REG);
111 outb(0x01, REG);
112 outb(0x55, REG);
113 outb(0x55, REG);
114 return 0;
115 }
116
superio_exit(void)117 static inline void superio_exit(void)
118 {
119 outb(0x02, REG);
120 outb(0x02, VAL);
121 release_region(REG, 2);
122 }
123
superio_select(int ldn)124 static inline void superio_select(int ldn)
125 {
126 outb(LDNREG, REG);
127 outb(ldn, VAL);
128 }
129
superio_inb(int reg)130 static inline int superio_inb(int reg)
131 {
132 outb(reg, REG);
133 return inb(VAL);
134 }
135
superio_outb(int val,int reg)136 static inline void superio_outb(int val, int reg)
137 {
138 outb(reg, REG);
139 outb(val, VAL);
140 }
141
superio_inw(int reg)142 static inline int superio_inw(int reg)
143 {
144 int val;
145 outb(reg++, REG);
146 val = inb(VAL) << 8;
147 outb(reg, REG);
148 val |= inb(VAL);
149 return val;
150 }
151
superio_outw(int val,int reg)152 static inline void superio_outw(int val, int reg)
153 {
154 outb(reg++, REG);
155 outb(val >> 8, VAL);
156 outb(reg, REG);
157 outb(val, VAL);
158 }
159
160 /* Internal function, should be called after superio_select(GPIO) */
_wdt_update_timeout(unsigned int t)161 static void _wdt_update_timeout(unsigned int t)
162 {
163 unsigned char cfg = WDT_KRST;
164
165 if (testmode)
166 cfg = 0;
167
168 if (t <= max_units)
169 cfg |= WDT_TOV1;
170 else
171 t /= 60;
172
173 if (chip_type != IT8721_ID)
174 cfg |= WDT_PWROK;
175
176 superio_outb(cfg, WDTCFG);
177 superio_outb(t, WDTVALLSB);
178 if (max_units > 255)
179 superio_outb(t >> 8, WDTVALMSB);
180 }
181
wdt_update_timeout(unsigned int t)182 static int wdt_update_timeout(unsigned int t)
183 {
184 int ret;
185
186 ret = superio_enter();
187 if (ret)
188 return ret;
189
190 superio_select(GPIO);
191 _wdt_update_timeout(t);
192 superio_exit();
193
194 return 0;
195 }
196
wdt_round_time(int t)197 static int wdt_round_time(int t)
198 {
199 t += 59;
200 t -= t % 60;
201 return t;
202 }
203
204 /* watchdog timer handling */
205
wdt_start(struct watchdog_device * wdd)206 static int wdt_start(struct watchdog_device *wdd)
207 {
208 return wdt_update_timeout(wdd->timeout);
209 }
210
wdt_stop(struct watchdog_device * wdd)211 static int wdt_stop(struct watchdog_device *wdd)
212 {
213 return wdt_update_timeout(0);
214 }
215
216 /**
217 * wdt_set_timeout - set a new timeout value with watchdog ioctl
218 * @t: timeout value in seconds
219 *
220 * The hardware device has a 8 or 16 bit watchdog timer (depends on
221 * chip version) that can be configured to count seconds or minutes.
222 *
223 * Used within WDIOC_SETTIMEOUT watchdog device ioctl.
224 */
225
wdt_set_timeout(struct watchdog_device * wdd,unsigned int t)226 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
227 {
228 int ret = 0;
229
230 if (t > max_units)
231 t = wdt_round_time(t);
232
233 wdd->timeout = t;
234
235 if (watchdog_hw_running(wdd))
236 ret = wdt_update_timeout(t);
237
238 return ret;
239 }
240
241 static const struct watchdog_info ident = {
242 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
243 .firmware_version = 1,
244 .identity = WATCHDOG_NAME,
245 };
246
247 static const struct watchdog_ops wdt_ops = {
248 .owner = THIS_MODULE,
249 .start = wdt_start,
250 .stop = wdt_stop,
251 .set_timeout = wdt_set_timeout,
252 };
253
254 static struct watchdog_device wdt_dev = {
255 .info = &ident,
256 .ops = &wdt_ops,
257 .min_timeout = 1,
258 };
259
it87_wdt_init(void)260 static int __init it87_wdt_init(void)
261 {
262 u8 chip_rev;
263 int rc;
264
265 rc = superio_enter();
266 if (rc)
267 return rc;
268
269 chip_type = superio_inw(CHIPID);
270 chip_rev = superio_inb(CHIPREV) & 0x0f;
271 superio_exit();
272
273 switch (chip_type) {
274 case IT8702_ID:
275 max_units = 255;
276 break;
277 case IT8712_ID:
278 max_units = (chip_rev < 8) ? 255 : 65535;
279 break;
280 case IT8716_ID:
281 case IT8726_ID:
282 max_units = 65535;
283 break;
284 case IT8607_ID:
285 case IT8620_ID:
286 case IT8622_ID:
287 case IT8625_ID:
288 case IT8628_ID:
289 case IT8655_ID:
290 case IT8665_ID:
291 case IT8686_ID:
292 case IT8718_ID:
293 case IT8720_ID:
294 case IT8721_ID:
295 case IT8728_ID:
296 case IT8783_ID:
297 max_units = 65535;
298 break;
299 case IT8705_ID:
300 pr_err("Unsupported Chip found, Chip %04x Revision %02x\n",
301 chip_type, chip_rev);
302 return -ENODEV;
303 case NO_DEV_ID:
304 pr_err("no device\n");
305 return -ENODEV;
306 default:
307 pr_err("Unknown Chip found, Chip %04x Revision %04x\n",
308 chip_type, chip_rev);
309 return -ENODEV;
310 }
311
312 rc = superio_enter();
313 if (rc)
314 return rc;
315
316 superio_select(GPIO);
317 superio_outb(WDT_TOV1, WDTCFG);
318 superio_outb(0x00, WDTCTRL);
319 superio_exit();
320
321 if (timeout < 1 || timeout > max_units * 60) {
322 timeout = DEFAULT_TIMEOUT;
323 pr_warn("Timeout value out of range, use default %d sec\n",
324 DEFAULT_TIMEOUT);
325 }
326
327 if (timeout > max_units)
328 timeout = wdt_round_time(timeout);
329
330 wdt_dev.timeout = timeout;
331 wdt_dev.max_timeout = max_units * 60;
332
333 watchdog_stop_on_reboot(&wdt_dev);
334 rc = watchdog_register_device(&wdt_dev);
335 if (rc) {
336 pr_err("Cannot register watchdog device (err=%d)\n", rc);
337 return rc;
338 }
339
340 pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
341 chip_type, chip_rev, timeout, nowayout, testmode);
342
343 return 0;
344 }
345
it87_wdt_exit(void)346 static void __exit it87_wdt_exit(void)
347 {
348 watchdog_unregister_device(&wdt_dev);
349 }
350
351 module_init(it87_wdt_init);
352 module_exit(it87_wdt_exit);
353
354 MODULE_AUTHOR("Oliver Schuster");
355 MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
356 MODULE_LICENSE("GPL");
357