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, IT8613, IT8620, IT8622, IT8625, IT8628, IT8655, IT8659,
17 * IT8665, IT8686, IT8702, IT8712, IT8716, IT8718, IT8720, IT8721,
18 * IT8726, IT8728, IT8772, IT8783, IT8784 and IT8786.
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 IT8613_ID 0x8613
54#define IT8620_ID 0x8620
55#define IT8622_ID 0x8622
56#define IT8625_ID 0x8625
57#define IT8628_ID 0x8628
58#define IT8655_ID 0x8655
59#define IT8659_ID 0x8659
60#define IT8665_ID 0x8665
61#define IT8686_ID 0x8686
62#define IT8702_ID 0x8702
63#define IT8705_ID 0x8705
64#define IT8712_ID 0x8712
65#define IT8716_ID 0x8716
66#define IT8718_ID 0x8718
67#define IT8720_ID 0x8720
68#define IT8721_ID 0x8721
69#define IT8726_ID 0x8726 /* the data sheet suggest wrongly 0x8716 */
70#define IT8728_ID 0x8728
71#define IT8772_ID 0x8772
72#define IT8783_ID 0x8783
73#define IT8784_ID 0x8784
74#define IT8786_ID 0x8786
75
76/* GPIO Configuration Registers LDN=0x07 */
77#define WDTCTRL 0x71
78#define WDTCFG 0x72
79#define WDTVALLSB 0x73
80#define WDTVALMSB 0x74
81
82/* GPIO Bits WDTCFG */
83#define WDT_TOV1 0x80
84#define WDT_KRST 0x40
85#define WDT_TOVE 0x20
86#define WDT_PWROK 0x10 /* not in it8721 */
87#define WDT_INT_MASK 0x0f
88
89static unsigned int max_units, chip_type;
90
91static unsigned int timeout = DEFAULT_TIMEOUT;
92static int testmode = DEFAULT_TESTMODE;
93static bool nowayout = DEFAULT_NOWAYOUT;
94
95module_param(timeout, int, 0);
96MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default="
97 __MODULE_STRING(DEFAULT_TIMEOUT));
98module_param(testmode, int, 0);
99MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default="
100 __MODULE_STRING(DEFAULT_TESTMODE));
101module_param(nowayout, bool, 0);
102MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
103 __MODULE_STRING(WATCHDOG_NOWAYOUT));
104
105/* Superio Chip */
106
107static inline int superio_enter(void)
108{
109 /*
110 * Try to reserve REG and REG + 1 for exclusive access.
111 */
112 if (!request_muxed_region(REG, 2, WATCHDOG_NAME))
113 return -EBUSY;
114
115 outb(value: 0x87, REG);
116 outb(value: 0x01, REG);
117 outb(value: 0x55, REG);
118 outb(value: 0x55, REG);
119 return 0;
120}
121
122static inline void superio_exit(void)
123{
124 outb(value: 0x02, REG);
125 outb(value: 0x02, VAL);
126 release_region(REG, 2);
127}
128
129static inline void superio_select(int ldn)
130{
131 outb(LDNREG, REG);
132 outb(value: ldn, VAL);
133}
134
135static inline int superio_inb(int reg)
136{
137 outb(value: reg, REG);
138 return inb(VAL);
139}
140
141static inline void superio_outb(int val, int reg)
142{
143 outb(value: reg, REG);
144 outb(value: val, VAL);
145}
146
147static inline int superio_inw(int reg)
148{
149 int val;
150
151 outb(value: reg++, REG);
152 val = inb(VAL) << 8;
153 outb(value: reg, REG);
154 val |= inb(VAL);
155 return val;
156}
157
158/* Internal function, should be called after superio_select(GPIO) */
159static void _wdt_update_timeout(unsigned int t)
160{
161 unsigned char cfg = WDT_KRST;
162
163 if (testmode)
164 cfg = 0;
165
166 if (t <= max_units)
167 cfg |= WDT_TOV1;
168 else
169 t /= 60;
170
171 if (chip_type != IT8721_ID)
172 cfg |= WDT_PWROK;
173
174 superio_outb(val: cfg, WDTCFG);
175 superio_outb(val: t, WDTVALLSB);
176 if (max_units > 255)
177 superio_outb(val: t >> 8, WDTVALMSB);
178}
179
180static int wdt_update_timeout(unsigned int t)
181{
182 int ret;
183
184 ret = superio_enter();
185 if (ret)
186 return ret;
187
188 superio_select(GPIO);
189 _wdt_update_timeout(t);
190 superio_exit();
191
192 return 0;
193}
194
195static int wdt_round_time(int t)
196{
197 t += 59;
198 t -= t % 60;
199 return t;
200}
201
202/* watchdog timer handling */
203
204static int wdt_start(struct watchdog_device *wdd)
205{
206 return wdt_update_timeout(t: wdd->timeout);
207}
208
209static int wdt_stop(struct watchdog_device *wdd)
210{
211 return wdt_update_timeout(t: 0);
212}
213
214/**
215 * wdt_set_timeout - set a new timeout value with watchdog ioctl
216 * @wdd: pointer to the watchdog_device structure
217 * @t: timeout value in seconds
218 *
219 * The hardware device has a 8 or 16 bit watchdog timer (depends on
220 * chip version) that can be configured to count seconds or minutes.
221 *
222 * Used within WDIOC_SETTIMEOUT watchdog device ioctl.
223 *
224 * Return: 0 if the timeout was set successfully, or a negative error code on
225 * failure.
226 */
227
228static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
229{
230 int ret = 0;
231
232 if (t > max_units)
233 t = wdt_round_time(t);
234
235 wdd->timeout = t;
236
237 if (watchdog_hw_running(wdd))
238 ret = wdt_update_timeout(t);
239
240 return ret;
241}
242
243static const struct watchdog_info ident = {
244 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
245 .firmware_version = 1,
246 .identity = WATCHDOG_NAME,
247};
248
249static const struct watchdog_ops wdt_ops = {
250 .owner = THIS_MODULE,
251 .start = wdt_start,
252 .stop = wdt_stop,
253 .set_timeout = wdt_set_timeout,
254};
255
256static struct watchdog_device wdt_dev = {
257 .info = &ident,
258 .ops = &wdt_ops,
259 .min_timeout = 1,
260};
261
262static int __init it87_wdt_init(void)
263{
264 u8 chip_rev;
265 u8 ctrl;
266 int rc;
267
268 rc = superio_enter();
269 if (rc)
270 return rc;
271
272 chip_type = superio_inw(CHIPID);
273 chip_rev = superio_inb(CHIPREV) & 0x0f;
274 superio_exit();
275
276 switch (chip_type) {
277 case IT8702_ID:
278 max_units = 255;
279 break;
280 case IT8712_ID:
281 max_units = (chip_rev < 8) ? 255 : 65535;
282 break;
283 case IT8607_ID:
284 case IT8613_ID:
285 case IT8620_ID:
286 case IT8622_ID:
287 case IT8625_ID:
288 case IT8628_ID:
289 case IT8655_ID:
290 case IT8659_ID:
291 case IT8665_ID:
292 case IT8686_ID:
293 case IT8716_ID:
294 case IT8718_ID:
295 case IT8720_ID:
296 case IT8721_ID:
297 case IT8726_ID:
298 case IT8728_ID:
299 case IT8772_ID:
300 case IT8783_ID:
301 case IT8784_ID:
302 case IT8786_ID:
303 max_units = 65535;
304 break;
305 case IT8705_ID:
306 pr_err("Unsupported Chip found, Chip %04x Revision %02x\n",
307 chip_type, chip_rev);
308 return -ENODEV;
309 case NO_DEV_ID:
310 pr_err("no device\n");
311 return -ENODEV;
312 default:
313 pr_err("Unknown Chip found, Chip %04x Revision %04x\n",
314 chip_type, chip_rev);
315 return -ENODEV;
316 }
317
318 rc = superio_enter();
319 if (rc)
320 return rc;
321
322 superio_select(GPIO);
323 superio_outb(WDT_TOV1, WDTCFG);
324
325 switch (chip_type) {
326 case IT8784_ID:
327 case IT8786_ID:
328 ctrl = superio_inb(WDTCTRL);
329 ctrl &= 0x08;
330 superio_outb(val: ctrl, WDTCTRL);
331 break;
332 default:
333 superio_outb(val: 0x00, WDTCTRL);
334 }
335
336 superio_exit();
337
338 if (timeout < 1 || timeout > max_units * 60) {
339 timeout = DEFAULT_TIMEOUT;
340 pr_warn("Timeout value out of range, use default %d sec\n",
341 DEFAULT_TIMEOUT);
342 }
343
344 if (timeout > max_units)
345 timeout = wdt_round_time(t: timeout);
346
347 wdt_dev.timeout = timeout;
348 wdt_dev.max_timeout = max_units * 60;
349
350 watchdog_stop_on_reboot(wdd: &wdt_dev);
351 rc = watchdog_register_device(&wdt_dev);
352 if (rc) {
353 pr_err("Cannot register watchdog device (err=%d)\n", rc);
354 return rc;
355 }
356
357 pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
358 chip_type, chip_rev, timeout, nowayout, testmode);
359
360 return 0;
361}
362
363static void __exit it87_wdt_exit(void)
364{
365 watchdog_unregister_device(&wdt_dev);
366}
367
368module_init(it87_wdt_init);
369module_exit(it87_wdt_exit);
370
371MODULE_AUTHOR("Oliver Schuster");
372MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
373MODULE_LICENSE("GPL");
374

source code of linux/drivers/watchdog/it87_wdt.c