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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Watchdog driver for Technologic Systems TS-72xx based SBCs
4 * (TS-7200, TS-7250 and TS-7260). These boards have external
5 * glue logic CPLD chip, which includes programmable watchdog
6 * timer.
7 *
8 * Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi>
9 *
10 * This driver is based on ep93xx_wdt and wm831x_wdt drivers.
11 *
12 */
13
14#include <linux/platform_device.h>
15#include <linux/mod_devicetable.h>
16#include <linux/module.h>
17#include <linux/watchdog.h>
18#include <linux/io.h>
19
20#define TS72XX_WDT_DEFAULT_TIMEOUT 30
21
22static int timeout;
23module_param(timeout, int, 0);
24MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds.");
25
26static bool nowayout = WATCHDOG_NOWAYOUT;
27module_param(nowayout, bool, 0);
28MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
29
30/* priv->control_reg */
31#define TS72XX_WDT_CTRL_DISABLE 0x00
32#define TS72XX_WDT_CTRL_250MS 0x01
33#define TS72XX_WDT_CTRL_500MS 0x02
34#define TS72XX_WDT_CTRL_1SEC 0x03
35#define TS72XX_WDT_CTRL_RESERVED 0x04
36#define TS72XX_WDT_CTRL_2SEC 0x05
37#define TS72XX_WDT_CTRL_4SEC 0x06
38#define TS72XX_WDT_CTRL_8SEC 0x07
39
40/* priv->feed_reg */
41#define TS72XX_WDT_FEED_VAL 0x05
42
43struct ts72xx_wdt_priv {
44 void __iomem *control_reg;
45 void __iomem *feed_reg;
46 struct watchdog_device wdd;
47 unsigned char regval;
48};
49
50static int ts72xx_wdt_start(struct watchdog_device *wdd)
51{
52 struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
53
54 writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
55 writeb(priv->regval, priv->control_reg);
56
57 return 0;
58}
59
60static int ts72xx_wdt_stop(struct watchdog_device *wdd)
61{
62 struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
63
64 writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
65 writeb(TS72XX_WDT_CTRL_DISABLE, priv->control_reg);
66
67 return 0;
68}
69
70static int ts72xx_wdt_ping(struct watchdog_device *wdd)
71{
72 struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
73
74 writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
75
76 return 0;
77}
78
79static int ts72xx_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
80{
81 struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
82
83 if (to == 1) {
84 priv->regval = TS72XX_WDT_CTRL_1SEC;
85 } else if (to == 2) {
86 priv->regval = TS72XX_WDT_CTRL_2SEC;
87 } else if (to <= 4) {
88 priv->regval = TS72XX_WDT_CTRL_4SEC;
89 to = 4;
90 } else {
91 priv->regval = TS72XX_WDT_CTRL_8SEC;
92 if (to <= 8)
93 to = 8;
94 }
95
96 wdd->timeout = to;
97
98 if (watchdog_active(wdd)) {
99 ts72xx_wdt_stop(wdd);
100 ts72xx_wdt_start(wdd);
101 }
102
103 return 0;
104}
105
106static const struct watchdog_info ts72xx_wdt_ident = {
107 .options = WDIOF_KEEPALIVEPING |
108 WDIOF_SETTIMEOUT |
109 WDIOF_MAGICCLOSE,
110 .firmware_version = 1,
111 .identity = "TS-72XX WDT",
112};
113
114static const struct watchdog_ops ts72xx_wdt_ops = {
115 .owner = THIS_MODULE,
116 .start = ts72xx_wdt_start,
117 .stop = ts72xx_wdt_stop,
118 .ping = ts72xx_wdt_ping,
119 .set_timeout = ts72xx_wdt_settimeout,
120};
121
122static int ts72xx_wdt_probe(struct platform_device *pdev)
123{
124 struct device *dev = &pdev->dev;
125 struct ts72xx_wdt_priv *priv;
126 struct watchdog_device *wdd;
127 int ret;
128
129 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
130 if (!priv)
131 return -ENOMEM;
132
133 priv->control_reg = devm_platform_ioremap_resource(pdev, 0);
134 if (IS_ERR(priv->control_reg))
135 return PTR_ERR(priv->control_reg);
136
137 priv->feed_reg = devm_platform_ioremap_resource(pdev, 1);
138 if (IS_ERR(priv->feed_reg))
139 return PTR_ERR(priv->feed_reg);
140
141 wdd = &priv->wdd;
142 wdd->info = &ts72xx_wdt_ident;
143 wdd->ops = &ts72xx_wdt_ops;
144 wdd->min_timeout = 1;
145 wdd->max_hw_heartbeat_ms = 8000;
146 wdd->parent = dev;
147
148 watchdog_set_nowayout(wdd, nowayout);
149
150 wdd->timeout = TS72XX_WDT_DEFAULT_TIMEOUT;
151 watchdog_init_timeout(wdd, timeout, dev);
152
153 watchdog_set_drvdata(wdd, priv);
154
155 ret = devm_watchdog_register_device(dev, wdd);
156 if (ret)
157 return ret;
158
159 dev_info(dev, "TS-72xx Watchdog driver\n");
160
161 return 0;
162}
163
164static const struct of_device_id ts72xx_wdt_of_ids[] = {
165 { .compatible = "technologic,ts7200-wdt" },
166 { /* sentinel */ }
167};
168MODULE_DEVICE_TABLE(of, ts72xx_wdt_of_ids);
169
170static struct platform_driver ts72xx_wdt_driver = {
171 .probe = ts72xx_wdt_probe,
172 .driver = {
173 .name = "ts72xx-wdt",
174 .of_match_table = ts72xx_wdt_of_ids,
175 },
176};
177
178module_platform_driver(ts72xx_wdt_driver);
179
180MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
181MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
182MODULE_LICENSE("GPL");
183MODULE_ALIAS("platform:ts72xx-wdt");
1/*
2 * Watchdog driver for Technologic Systems TS-72xx based SBCs
3 * (TS-7200, TS-7250 and TS-7260). These boards have external
4 * glue logic CPLD chip, which includes programmable watchdog
5 * timer.
6 *
7 * Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi>
8 *
9 * This driver is based on ep93xx_wdt and wm831x_wdt drivers.
10 *
11 * This file is licensed under the terms of the GNU General Public
12 * License version 2. This program is licensed "as is" without any
13 * warranty of any kind, whether express or implied.
14 */
15
16#include <linux/fs.h>
17#include <linux/io.h>
18#include <linux/module.h>
19#include <linux/moduleparam.h>
20#include <linux/miscdevice.h>
21#include <linux/mutex.h>
22#include <linux/platform_device.h>
23#include <linux/slab.h>
24#include <linux/watchdog.h>
25#include <linux/uaccess.h>
26
27#define TS72XX_WDT_FEED_VAL 0x05
28#define TS72XX_WDT_DEFAULT_TIMEOUT 8
29
30static int timeout = TS72XX_WDT_DEFAULT_TIMEOUT;
31module_param(timeout, int, 0);
32MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. "
33 "(1 <= timeout <= 8, default="
34 __MODULE_STRING(TS72XX_WDT_DEFAULT_TIMEOUT)
35 ")");
36
37static bool nowayout = WATCHDOG_NOWAYOUT;
38module_param(nowayout, bool, 0);
39MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
40
41/**
42 * struct ts72xx_wdt - watchdog control structure
43 * @lock: lock that protects this structure
44 * @regval: watchdog timeout value suitable for control register
45 * @flags: flags controlling watchdog device state
46 * @control_reg: watchdog control register
47 * @feed_reg: watchdog feed register
48 * @pdev: back pointer to platform dev
49 */
50struct ts72xx_wdt {
51 struct mutex lock;
52 int regval;
53
54#define TS72XX_WDT_BUSY_FLAG 1
55#define TS72XX_WDT_EXPECT_CLOSE_FLAG 2
56 int flags;
57
58 void __iomem *control_reg;
59 void __iomem *feed_reg;
60
61 struct platform_device *pdev;
62};
63
64static struct platform_device *ts72xx_wdt_pdev;
65
66/*
67 * TS-72xx Watchdog supports following timeouts (value written
68 * to control register):
69 * value description
70 * -------------------------
71 * 0x00 watchdog disabled
72 * 0x01 250ms
73 * 0x02 500ms
74 * 0x03 1s
75 * 0x04 reserved
76 * 0x05 2s
77 * 0x06 4s
78 * 0x07 8s
79 *
80 * Timeouts below 1s are not very usable so we don't
81 * allow them at all.
82 *
83 * We provide two functions that convert between these:
84 * timeout_to_regval() and regval_to_timeout().
85 */
86static const struct {
87 int timeout;
88 int regval;
89} ts72xx_wdt_map[] = {
90 { 1, 3 },
91 { 2, 5 },
92 { 4, 6 },
93 { 8, 7 },
94};
95
96/**
97 * timeout_to_regval() - converts given timeout to control register value
98 * @new_timeout: timeout in seconds to be converted
99 *
100 * Function converts given @new_timeout into valid value that can
101 * be programmed into watchdog control register. When conversion is
102 * not possible, function returns %-EINVAL.
103 */
104static int timeout_to_regval(int new_timeout)
105{
106 int i;
107
108 /* first limit it to 1 - 8 seconds */
109 new_timeout = clamp_val(new_timeout, 1, 8);
110
111 for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
112 if (ts72xx_wdt_map[i].timeout >= new_timeout)
113 return ts72xx_wdt_map[i].regval;
114 }
115
116 return -EINVAL;
117}
118
119/**
120 * regval_to_timeout() - converts control register value to timeout
121 * @regval: control register value to be converted
122 *
123 * Function converts given @regval to timeout in seconds (1, 2, 4 or 8).
124 * If @regval cannot be converted, function returns %-EINVAL.
125 */
126static int regval_to_timeout(int regval)
127{
128 int i;
129
130 for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
131 if (ts72xx_wdt_map[i].regval == regval)
132 return ts72xx_wdt_map[i].timeout;
133 }
134
135 return -EINVAL;
136}
137
138/**
139 * ts72xx_wdt_kick() - kick the watchdog
140 * @wdt: watchdog to be kicked
141 *
142 * Called with @wdt->lock held.
143 */
144static inline void ts72xx_wdt_kick(struct ts72xx_wdt *wdt)
145{
146 __raw_writeb(TS72XX_WDT_FEED_VAL, wdt->feed_reg);
147}
148
149/**
150 * ts72xx_wdt_start() - starts the watchdog timer
151 * @wdt: watchdog to be started
152 *
153 * This function programs timeout to watchdog timer
154 * and starts it.
155 *
156 * Called with @wdt->lock held.
157 */
158static void ts72xx_wdt_start(struct ts72xx_wdt *wdt)
159{
160 /*
161 * To program the wdt, it first must be "fed" and
162 * only after that (within 30 usecs) the configuration
163 * can be changed.
164 */
165 ts72xx_wdt_kick(wdt);
166 __raw_writeb((u8)wdt->regval, wdt->control_reg);
167}
168
169/**
170 * ts72xx_wdt_stop() - stops the watchdog timer
171 * @wdt: watchdog to be stopped
172 *
173 * Called with @wdt->lock held.
174 */
175static void ts72xx_wdt_stop(struct ts72xx_wdt *wdt)
176{
177 ts72xx_wdt_kick(wdt);
178 __raw_writeb(0, wdt->control_reg);
179}
180
181static int ts72xx_wdt_open(struct inode *inode, struct file *file)
182{
183 struct ts72xx_wdt *wdt = platform_get_drvdata(ts72xx_wdt_pdev);
184 int regval;
185
186 /*
187 * Try to convert default timeout to valid register
188 * value first.
189 */
190 regval = timeout_to_regval(timeout);
191 if (regval < 0) {
192 dev_err(&wdt->pdev->dev,
193 "failed to convert timeout (%d) to register value\n",
194 timeout);
195 return regval;
196 }
197
198 if (mutex_lock_interruptible(&wdt->lock))
199 return -ERESTARTSYS;
200
201 if ((wdt->flags & TS72XX_WDT_BUSY_FLAG) != 0) {
202 mutex_unlock(&wdt->lock);
203 return -EBUSY;
204 }
205
206 wdt->flags = TS72XX_WDT_BUSY_FLAG;
207 wdt->regval = regval;
208 file->private_data = wdt;
209
210 ts72xx_wdt_start(wdt);
211
212 mutex_unlock(&wdt->lock);
213 return nonseekable_open(inode, file);
214}
215
216static int ts72xx_wdt_release(struct inode *inode, struct file *file)
217{
218 struct ts72xx_wdt *wdt = file->private_data;
219
220 if (mutex_lock_interruptible(&wdt->lock))
221 return -ERESTARTSYS;
222
223 if ((wdt->flags & TS72XX_WDT_EXPECT_CLOSE_FLAG) != 0) {
224 ts72xx_wdt_stop(wdt);
225 } else {
226 dev_warn(&wdt->pdev->dev,
227 "TS-72XX WDT device closed unexpectly. "
228 "Watchdog timer will not stop!\n");
229 /*
230 * Kick it one more time, to give userland some time
231 * to recover (for example, respawning the kicker
232 * daemon).
233 */
234 ts72xx_wdt_kick(wdt);
235 }
236
237 wdt->flags = 0;
238
239 mutex_unlock(&wdt->lock);
240 return 0;
241}
242
243static ssize_t ts72xx_wdt_write(struct file *file,
244 const char __user *data,
245 size_t len,
246 loff_t *ppos)
247{
248 struct ts72xx_wdt *wdt = file->private_data;
249
250 if (!len)
251 return 0;
252
253 if (mutex_lock_interruptible(&wdt->lock))
254 return -ERESTARTSYS;
255
256 ts72xx_wdt_kick(wdt);
257
258 /*
259 * Support for magic character closing. User process
260 * writes 'V' into the device, just before it is closed.
261 * This means that we know that the wdt timer can be
262 * stopped after user closes the device.
263 */
264 if (!nowayout) {
265 int i;
266
267 for (i = 0; i < len; i++) {
268 char c;
269
270 /* In case it was set long ago */
271 wdt->flags &= ~TS72XX_WDT_EXPECT_CLOSE_FLAG;
272
273 if (get_user(c, data + i)) {
274 mutex_unlock(&wdt->lock);
275 return -EFAULT;
276 }
277 if (c == 'V') {
278 wdt->flags |= TS72XX_WDT_EXPECT_CLOSE_FLAG;
279 break;
280 }
281 }
282 }
283
284 mutex_unlock(&wdt->lock);
285 return len;
286}
287
288static const struct watchdog_info winfo = {
289 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
290 WDIOF_MAGICCLOSE,
291 .firmware_version = 1,
292 .identity = "TS-72XX WDT",
293};
294
295static long ts72xx_wdt_ioctl(struct file *file, unsigned int cmd,
296 unsigned long arg)
297{
298 struct ts72xx_wdt *wdt = file->private_data;
299 void __user *argp = (void __user *)arg;
300 int __user *p = (int __user *)argp;
301 int error = 0;
302
303 if (mutex_lock_interruptible(&wdt->lock))
304 return -ERESTARTSYS;
305
306 switch (cmd) {
307 case WDIOC_GETSUPPORT:
308 if (copy_to_user(argp, &winfo, sizeof(winfo)))
309 error = -EFAULT;
310 break;
311
312 case WDIOC_GETSTATUS:
313 case WDIOC_GETBOOTSTATUS:
314 error = put_user(0, p);
315 break;
316
317 case WDIOC_KEEPALIVE:
318 ts72xx_wdt_kick(wdt);
319 break;
320
321 case WDIOC_SETOPTIONS: {
322 int options;
323
324 error = get_user(options, p);
325 if (error)
326 break;
327
328 error = -EINVAL;
329
330 if ((options & WDIOS_DISABLECARD) != 0) {
331 ts72xx_wdt_stop(wdt);
332 error = 0;
333 }
334 if ((options & WDIOS_ENABLECARD) != 0) {
335 ts72xx_wdt_start(wdt);
336 error = 0;
337 }
338
339 break;
340 }
341
342 case WDIOC_SETTIMEOUT: {
343 int new_timeout;
344 int regval;
345
346 error = get_user(new_timeout, p);
347 if (error)
348 break;
349
350 regval = timeout_to_regval(new_timeout);
351 if (regval < 0) {
352 error = regval;
353 break;
354 }
355 ts72xx_wdt_stop(wdt);
356 wdt->regval = regval;
357 ts72xx_wdt_start(wdt);
358
359 /*FALLTHROUGH*/
360 }
361
362 case WDIOC_GETTIMEOUT:
363 error = put_user(regval_to_timeout(wdt->regval), p);
364 break;
365
366 default:
367 error = -ENOTTY;
368 break;
369 }
370
371 mutex_unlock(&wdt->lock);
372 return error;
373}
374
375static const struct file_operations ts72xx_wdt_fops = {
376 .owner = THIS_MODULE,
377 .llseek = no_llseek,
378 .open = ts72xx_wdt_open,
379 .release = ts72xx_wdt_release,
380 .write = ts72xx_wdt_write,
381 .unlocked_ioctl = ts72xx_wdt_ioctl,
382};
383
384static struct miscdevice ts72xx_wdt_miscdev = {
385 .minor = WATCHDOG_MINOR,
386 .name = "watchdog",
387 .fops = &ts72xx_wdt_fops,
388};
389
390static int ts72xx_wdt_probe(struct platform_device *pdev)
391{
392 struct ts72xx_wdt *wdt;
393 struct resource *r1, *r2;
394 int error = 0;
395
396 wdt = devm_kzalloc(&pdev->dev, sizeof(struct ts72xx_wdt), GFP_KERNEL);
397 if (!wdt)
398 return -ENOMEM;
399
400 r1 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
401 wdt->control_reg = devm_ioremap_resource(&pdev->dev, r1);
402 if (IS_ERR(wdt->control_reg))
403 return PTR_ERR(wdt->control_reg);
404
405 r2 = platform_get_resource(pdev, IORESOURCE_MEM, 1);
406 wdt->feed_reg = devm_ioremap_resource(&pdev->dev, r2);
407 if (IS_ERR(wdt->feed_reg))
408 return PTR_ERR(wdt->feed_reg);
409
410 platform_set_drvdata(pdev, wdt);
411 ts72xx_wdt_pdev = pdev;
412 wdt->pdev = pdev;
413 mutex_init(&wdt->lock);
414
415 /* make sure that the watchdog is disabled */
416 ts72xx_wdt_stop(wdt);
417
418 error = misc_register(&ts72xx_wdt_miscdev);
419 if (error) {
420 dev_err(&pdev->dev, "failed to register miscdev\n");
421 return error;
422 }
423
424 dev_info(&pdev->dev, "TS-72xx Watchdog driver\n");
425
426 return 0;
427}
428
429static int ts72xx_wdt_remove(struct platform_device *pdev)
430{
431 misc_deregister(&ts72xx_wdt_miscdev);
432 return 0;
433}
434
435static struct platform_driver ts72xx_wdt_driver = {
436 .probe = ts72xx_wdt_probe,
437 .remove = ts72xx_wdt_remove,
438 .driver = {
439 .name = "ts72xx-wdt",
440 },
441};
442
443module_platform_driver(ts72xx_wdt_driver);
444
445MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
446MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
447MODULE_LICENSE("GPL");
448MODULE_ALIAS("platform:ts72xx-wdt");