it87_wdt.c

  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/bits.h>
 24#include <linux/dmi.h>
 25#include <linux/errno.h>
 26#include <linux/init.h>
 27#include <linux/io.h>
 28#include <linux/ioport.h>
 29#include <linux/module.h>
 30#include <linux/moduleparam.h>
 31#include <linux/printk.h>
 32#include <linux/types.h>
 33#include <linux/watchdog.h>
 34
 35#define WATCHDOG_NAME		"IT87 WDT"
 36
 37/* Defaults for Module Parameter */
 38#define DEFAULT_TIMEOUT		60
 39#define DEFAULT_TESTMODE	0
 40#define DEFAULT_NOWAYOUT	WATCHDOG_NOWAYOUT
 41
 42/* IO Ports */
 43#define REG		0x2e
 44#define VAL		0x2f
 45
 46/* Logical device Numbers LDN */
 47#define EC		0x04
 48#define GPIO		0x07
 49
 50/* Configuration Registers and Functions */
 51#define LDNREG		0x07
 52#define CHIPID		0x20
 53#define CHIPREV		0x22
 54
 55/* Chip Id numbers */
 56#define NO_DEV_ID	0xffff
 57#define IT8607_ID	0x8607
 58#define IT8613_ID	0x8613
 59#define IT8620_ID	0x8620
 60#define IT8622_ID	0x8622
 61#define IT8625_ID	0x8625
 62#define IT8628_ID	0x8628
 63#define IT8655_ID	0x8655
 64#define IT8659_ID	0x8659
 65#define IT8665_ID	0x8665
 66#define IT8686_ID	0x8686
 67#define IT8702_ID	0x8702
 68#define IT8705_ID	0x8705
 69#define IT8712_ID	0x8712
 70#define IT8716_ID	0x8716
 71#define IT8718_ID	0x8718
 72#define IT8720_ID	0x8720
 73#define IT8721_ID	0x8721
 74#define IT8726_ID	0x8726	/* the data sheet suggest wrongly 0x8716 */
 75#define IT8728_ID	0x8728
 76#define IT8772_ID	0x8772
 77#define IT8783_ID	0x8783
 78#define IT8784_ID	0x8784
 79#define IT8786_ID	0x8786
 80
 81/* Environment Controller Configuration Registers LDN=0x04 */
 82#define SCR1		0xfa
 83
 84/* Environment Controller Bits SCR1 */
 85#define WDT_PWRGD	0x20
 86
 87/* GPIO Configuration Registers LDN=0x07 */
 88#define WDTCTRL		0x71
 89#define WDTCFG		0x72
 90#define WDTVALLSB	0x73
 91#define WDTVALMSB	0x74
 92
 93/* GPIO Bits WDTCFG */
 94#define WDT_TOV1	0x80
 95#define WDT_KRST	0x40
 96#define WDT_TOVE	0x20
 97#define WDT_PWROK	0x10 /* not in it8721 */
 98#define WDT_INT_MASK	0x0f
 99
100static unsigned int max_units, chip_type;
101
102static unsigned int timeout = DEFAULT_TIMEOUT;
103static int testmode = DEFAULT_TESTMODE;
104static bool nowayout = DEFAULT_NOWAYOUT;
105
106module_param(timeout, int, 0);
107MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default="
108		__MODULE_STRING(DEFAULT_TIMEOUT));
109module_param(testmode, int, 0);
110MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default="
111		__MODULE_STRING(DEFAULT_TESTMODE));
112module_param(nowayout, bool, 0);
113MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
114		__MODULE_STRING(WATCHDOG_NOWAYOUT));
115
116/* Superio Chip */
117
118static inline int superio_enter(void)
119{
120	/*
121	 * Try to reserve REG and REG + 1 for exclusive access.
122	 */
123	if (!request_muxed_region(REG, 2, WATCHDOG_NAME))
124		return -EBUSY;
125
126	outb(0x87, REG);
127	outb(0x01, REG);
128	outb(0x55, REG);
129	outb(0x55, REG);
130	return 0;
131}
132
133static inline void superio_exit(void)
134{
135	outb(0x02, REG);
136	outb(0x02, VAL);
137	release_region(REG, 2);
138}
139
140static inline void superio_select(int ldn)
141{
142	outb(LDNREG, REG);
143	outb(ldn, VAL);
144}
145
146static inline int superio_inb(int reg)
147{
148	outb(reg, REG);
149	return inb(VAL);
150}
151
152static inline void superio_outb(int val, int reg)
153{
154	outb(reg, REG);
155	outb(val, VAL);
156}
157
158static inline int superio_inw(int reg)
159{
160	int val;
161
162	outb(reg++, REG);
163	val = inb(VAL) << 8;
164	outb(reg, REG);
165	val |= inb(VAL);
166	return val;
167}
168
169/* Internal function, should be called after superio_select(GPIO) */
170static void _wdt_update_timeout(unsigned int t)
171{
172	unsigned char cfg = WDT_KRST;
173
174	if (testmode)
175		cfg = 0;
176
177	if (t <= max_units)
178		cfg |= WDT_TOV1;
179	else
180		t /= 60;
181
182	if (chip_type != IT8721_ID)
183		cfg |= WDT_PWROK;
184
185	superio_outb(cfg, WDTCFG);
186	superio_outb(t, WDTVALLSB);
187	if (max_units > 255)
188		superio_outb(t >> 8, WDTVALMSB);
189}
190
191/* Internal function, should be called after superio_select(GPIO) */
192static bool _wdt_running(void)
193{
194	return superio_inb(WDTVALLSB) || (max_units > 255 && superio_inb(WDTVALMSB));
195}
196
197static int wdt_update_timeout(unsigned int t)
198{
199	int ret;
200
201	ret = superio_enter();
202	if (ret)
203		return ret;
204
205	superio_select(GPIO);
206	_wdt_update_timeout(t);
207	superio_exit();
208
209	return 0;
210}
211
212static int wdt_round_time(int t)
213{
214	t += 59;
215	t -= t % 60;
216	return t;
217}
218
219/* watchdog timer handling */
220
221static int wdt_start(struct watchdog_device *wdd)
222{
223	return wdt_update_timeout(wdd->timeout);
224}
225
226static int wdt_stop(struct watchdog_device *wdd)
227{
228	return wdt_update_timeout(0);
229}
230
231/**
232 *	wdt_set_timeout - set a new timeout value with watchdog ioctl
233 *	@wdd: pointer to the watchdog_device structure
234 *	@t: timeout value in seconds
235 *
236 *	The hardware device has a 8 or 16 bit watchdog timer (depends on
237 *	chip version) that can be configured to count seconds or minutes.
238 *
239 *	Used within WDIOC_SETTIMEOUT watchdog device ioctl.
240 *
241 *	Return: 0 if the timeout was set successfully, or a negative error code on
242 *	failure.
243 */
244
245static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
246{
247	int ret = 0;
248
249	if (t > max_units)
250		t = wdt_round_time(t);
251
252	wdd->timeout = t;
253
254	if (watchdog_hw_running(wdd))
255		ret = wdt_update_timeout(t);
256
257	return ret;
258}
259
260enum {
261	IT87_WDT_OUTPUT_THROUGH_PWRGD	= BIT(0),
262};
263
264static const struct dmi_system_id it87_quirks[] = {
265	{
266		/* Qotom Q30900P (IT8786) */
267		.matches = {
268			DMI_EXACT_MATCH(DMI_BOARD_NAME, "QCML04"),
269		},
270		.driver_data = (void *)IT87_WDT_OUTPUT_THROUGH_PWRGD,
271	},
272	{}
273};
274
275static const struct watchdog_info ident = {
276	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
277	.firmware_version = 1,
278	.identity = WATCHDOG_NAME,
279};
280
281static const struct watchdog_ops wdt_ops = {
282	.owner = THIS_MODULE,
283	.start = wdt_start,
284	.stop = wdt_stop,
285	.set_timeout = wdt_set_timeout,
286};
287
288static struct watchdog_device wdt_dev = {
289	.info = &ident,
290	.ops = &wdt_ops,
291	.min_timeout = 1,
292};
293
294static int __init it87_wdt_init(void)
295{
296	const struct dmi_system_id *dmi_id;
297	u8  chip_rev;
298	u8 ctrl;
299	int quirks = 0;
300	int rc;
301
302	rc = superio_enter();
303	if (rc)
304		return rc;
305
306	chip_type = superio_inw(CHIPID);
307	chip_rev  = superio_inb(CHIPREV) & 0x0f;
308	superio_exit();
309
310	dmi_id = dmi_first_match(it87_quirks);
311	if (dmi_id)
312		quirks = (long)dmi_id->driver_data;
313
314	switch (chip_type) {
315	case IT8702_ID:
316		max_units = 255;
317		break;
318	case IT8712_ID:
319		max_units = (chip_rev < 8) ? 255 : 65535;
320		break;
321	case IT8607_ID:
322	case IT8613_ID:
323	case IT8620_ID:
324	case IT8622_ID:
325	case IT8625_ID:
326	case IT8628_ID:
327	case IT8655_ID:
328	case IT8659_ID:
329	case IT8665_ID:
330	case IT8686_ID:
331	case IT8716_ID:
332	case IT8718_ID:
333	case IT8720_ID:
334	case IT8721_ID:
335	case IT8726_ID:
336	case IT8728_ID:
337	case IT8772_ID:
338	case IT8783_ID:
339	case IT8784_ID:
340	case IT8786_ID:
341		max_units = 65535;
342		break;
343	case IT8705_ID:
344		pr_err("Unsupported Chip found, Chip %04x Revision %02x\n",
345		       chip_type, chip_rev);
346		return -ENODEV;
347	case NO_DEV_ID:
348		pr_err("no device\n");
349		return -ENODEV;
350	default:
351		pr_err("Unknown Chip found, Chip %04x Revision %04x\n",
352		       chip_type, chip_rev);
353		return -ENODEV;
354	}
355
356	rc = superio_enter();
357	if (rc)
358		return rc;
359
360	superio_select(GPIO);
361	superio_outb(WDT_TOV1, WDTCFG);
362
363	switch (chip_type) {
364	case IT8784_ID:
365	case IT8786_ID:
366		ctrl = superio_inb(WDTCTRL);
367		ctrl &= 0x08;
368		superio_outb(ctrl, WDTCTRL);
369		break;
370	default:
371		superio_outb(0x00, WDTCTRL);
372	}
373
374	if (quirks & IT87_WDT_OUTPUT_THROUGH_PWRGD) {
375		superio_select(EC);
376		ctrl = superio_inb(SCR1);
377		if (!(ctrl & WDT_PWRGD)) {
378			ctrl |= WDT_PWRGD;
379			superio_outb(ctrl, SCR1);
380		}
381	}
382
383	/* wdt already left running by firmware? */
384	if (_wdt_running()) {
385		pr_info("Left running by firmware.\n");
386		set_bit(WDOG_HW_RUNNING, &wdt_dev.status);
387	}
388
389	superio_exit();
390
391	if (timeout < 1 || timeout > max_units * 60) {
392		timeout = DEFAULT_TIMEOUT;
393		pr_warn("Timeout value out of range, use default %d sec\n",
394			DEFAULT_TIMEOUT);
395	}
396
397	if (timeout > max_units)
398		timeout = wdt_round_time(timeout);
399
400	wdt_dev.timeout = timeout;
401	wdt_dev.max_timeout = max_units * 60;
402
403	watchdog_stop_on_reboot(&wdt_dev);
404	rc = watchdog_register_device(&wdt_dev);
405	if (rc)
406		return rc;
407
408	pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
409		chip_type, chip_rev, timeout, nowayout, testmode);
410
411	return 0;
412}
413
414static void __exit it87_wdt_exit(void)
415{
416	watchdog_unregister_device(&wdt_dev);
417}
418
419module_init(it87_wdt_init);
420module_exit(it87_wdt_exit);
421
422MODULE_AUTHOR("Oliver Schuster");
423MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
424MODULE_LICENSE("GPL");