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