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15#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16
17#include <linux/clk.h>
18#include <linux/errno.h>
19#include <linux/init.h>
20#include <linux/interrupt.h>
21#include <linux/io.h>
22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/moduleparam.h>
25#include <linux/platform_device.h>
26#include <linux/reboot.h>
27#include <linux/types.h>
28#include <linux/watchdog.h>
29#include <linux/jiffies.h>
30#include <linux/timer.h>
31#include <linux/bitops.h>
32#include <linux/uaccess.h>
33#include <linux/of.h>
34#include <linux/of_irq.h>
35
36#include "at91sam9_wdt.h"
37
38#define DRV_NAME "AT91SAM9 Watchdog"
39
40#define wdt_read(wdt, field) \
41 readl_relaxed((wdt)->base + (field))
42#define wdt_write(wtd, field, val) \
43 writel_relaxed((val), (wdt)->base + (field))
44
45
46
47
48
49#define ticks_to_hz_rounddown(t) ((((t) + 1) * HZ) >> 8)
50#define ticks_to_hz_roundup(t) (((((t) + 1) * HZ) + 255) >> 8)
51#define ticks_to_secs(t) (((t) + 1) >> 8)
52#define secs_to_ticks(s) ((s) ? (((s) << 8) - 1) : 0)
53
54#define WDT_MR_RESET 0x3FFF2FFF
55
56
57#define WDT_COUNTER_MAX_TICKS 0xFFF
58
59
60#define WDT_COUNTER_MAX_SECS ticks_to_secs(WDT_COUNTER_MAX_TICKS)
61
62
63#define WDT_HW_TIMEOUT 2
64
65
66#define WDT_TIMEOUT (HZ/2)
67
68
69#define WDT_HEARTBEAT 15
70static int heartbeat;
71module_param(heartbeat, int, 0);
72MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
73 "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
74
75static bool nowayout = WATCHDOG_NOWAYOUT;
76module_param(nowayout, bool, 0);
77MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
78 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
79
80#define to_wdt(wdd) container_of(wdd, struct at91wdt, wdd)
81struct at91wdt {
82 struct watchdog_device wdd;
83 void __iomem *base;
84 unsigned long next_heartbeat;
85 struct timer_list timer;
86 u32 mr;
87 u32 mr_mask;
88 unsigned long heartbeat;
89 bool nowayout;
90 unsigned int irq;
91 struct clk *sclk;
92};
93
94
95
96static irqreturn_t wdt_interrupt(int irq, void *dev_id)
97{
98 struct at91wdt *wdt = (struct at91wdt *)dev_id;
99
100 if (wdt_read(wdt, AT91_WDT_SR)) {
101 pr_crit("at91sam9 WDT software reset\n");
102 emergency_restart();
103 pr_crit("Reboot didn't ?????\n");
104 }
105
106 return IRQ_HANDLED;
107}
108
109
110
111
112static inline void at91_wdt_reset(struct at91wdt *wdt)
113{
114 wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
115}
116
117
118
119
120static void at91_ping(struct timer_list *t)
121{
122 struct at91wdt *wdt = from_timer(wdt, t, timer);
123 if (time_before(jiffies, wdt->next_heartbeat) ||
124 !watchdog_active(&wdt->wdd)) {
125 at91_wdt_reset(wdt);
126 mod_timer(&wdt->timer, jiffies + wdt->heartbeat);
127 } else {
128 pr_crit("I will reset your machine !\n");
129 }
130}
131
132static int at91_wdt_start(struct watchdog_device *wdd)
133{
134 struct at91wdt *wdt = to_wdt(wdd);
135
136 wdt->next_heartbeat = jiffies + wdd->timeout * HZ;
137 return 0;
138}
139
140static int at91_wdt_stop(struct watchdog_device *wdd)
141{
142
143 return 0;
144}
145
146static int at91_wdt_set_timeout(struct watchdog_device *wdd, unsigned int new_timeout)
147{
148 wdd->timeout = new_timeout;
149 return at91_wdt_start(wdd);
150}
151
152static int at91_wdt_init(struct platform_device *pdev, struct at91wdt *wdt)
153{
154 u32 tmp;
155 u32 delta;
156 u32 value;
157 int err;
158 u32 mask = wdt->mr_mask;
159 unsigned long min_heartbeat = 1;
160 unsigned long max_heartbeat;
161 struct device *dev = &pdev->dev;
162
163 tmp = wdt_read(wdt, AT91_WDT_MR);
164 if ((tmp & mask) != (wdt->mr & mask)) {
165 if (tmp == WDT_MR_RESET) {
166 wdt_write(wdt, AT91_WDT_MR, wdt->mr);
167 tmp = wdt_read(wdt, AT91_WDT_MR);
168 }
169 }
170
171 if (tmp & AT91_WDT_WDDIS) {
172 if (wdt->mr & AT91_WDT_WDDIS)
173 return 0;
174 dev_err(dev, "watchdog is disabled\n");
175 return -EINVAL;
176 }
177
178 value = tmp & AT91_WDT_WDV;
179 delta = (tmp & AT91_WDT_WDD) >> 16;
180
181 if (delta < value)
182 min_heartbeat = ticks_to_hz_roundup(value - delta);
183
184 max_heartbeat = ticks_to_hz_rounddown(value);
185 if (!max_heartbeat) {
186 dev_err(dev,
187 "heartbeat is too small for the system to handle it correctly\n");
188 return -EINVAL;
189 }
190
191
192
193
194
195
196
197 if ((max_heartbeat / 4) >= min_heartbeat)
198 wdt->heartbeat = max_heartbeat / 4;
199 else if ((max_heartbeat / 2) >= min_heartbeat)
200 wdt->heartbeat = max_heartbeat / 2;
201 else
202 wdt->heartbeat = min_heartbeat;
203
204 if (max_heartbeat < min_heartbeat + 4)
205 dev_warn(dev,
206 "min heartbeat and max heartbeat might be too close for the system to handle it correctly\n");
207
208 if ((tmp & AT91_WDT_WDFIEN) && wdt->irq) {
209 err = request_irq(wdt->irq, wdt_interrupt,
210 IRQF_SHARED | IRQF_IRQPOLL |
211 IRQF_NO_SUSPEND,
212 pdev->name, wdt);
213 if (err)
214 return err;
215 }
216
217 if ((tmp & wdt->mr_mask) != (wdt->mr & wdt->mr_mask))
218 dev_warn(dev,
219 "watchdog already configured differently (mr = %x expecting %x)\n",
220 tmp & wdt->mr_mask, wdt->mr & wdt->mr_mask);
221
222 timer_setup(&wdt->timer, at91_ping, 0);
223
224
225
226
227
228
229
230
231 mod_timer(&wdt->timer, jiffies + min_heartbeat);
232
233
234 if (watchdog_init_timeout(&wdt->wdd, 0, dev))
235 watchdog_init_timeout(&wdt->wdd, heartbeat, dev);
236 watchdog_set_nowayout(&wdt->wdd, wdt->nowayout);
237 err = watchdog_register_device(&wdt->wdd);
238 if (err)
239 goto out_stop_timer;
240
241 wdt->next_heartbeat = jiffies + wdt->wdd.timeout * HZ;
242
243 return 0;
244
245out_stop_timer:
246 del_timer(&wdt->timer);
247 return err;
248}
249
250
251
252static const struct watchdog_info at91_wdt_info = {
253 .identity = DRV_NAME,
254 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
255 WDIOF_MAGICCLOSE,
256};
257
258static const struct watchdog_ops at91_wdt_ops = {
259 .owner = THIS_MODULE,
260 .start = at91_wdt_start,
261 .stop = at91_wdt_stop,
262 .set_timeout = at91_wdt_set_timeout,
263};
264
265#if defined(CONFIG_OF)
266static int of_at91wdt_init(struct device_node *np, struct at91wdt *wdt)
267{
268 u32 min = 0;
269 u32 max = WDT_COUNTER_MAX_SECS;
270 const char *tmp;
271
272
273 wdt->irq = irq_of_parse_and_map(np, 0);
274 if (!wdt->irq)
275 dev_warn(wdt->wdd.parent, "failed to get IRQ from DT\n");
276
277 if (!of_property_read_u32_index(np, "atmel,max-heartbeat-sec", 0,
278 &max)) {
279 if (!max || max > WDT_COUNTER_MAX_SECS)
280 max = WDT_COUNTER_MAX_SECS;
281
282 if (!of_property_read_u32_index(np, "atmel,min-heartbeat-sec",
283 0, &min)) {
284 if (min >= max)
285 min = max - 1;
286 }
287 }
288
289 min = secs_to_ticks(min);
290 max = secs_to_ticks(max);
291
292 wdt->mr_mask = 0x3FFFFFFF;
293 wdt->mr = 0;
294 if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) &&
295 !strcmp(tmp, "software")) {
296 wdt->mr |= AT91_WDT_WDFIEN;
297 wdt->mr_mask &= ~AT91_WDT_WDRPROC;
298 } else {
299 wdt->mr |= AT91_WDT_WDRSTEN;
300 }
301
302 if (!of_property_read_string(np, "atmel,reset-type", &tmp) &&
303 !strcmp(tmp, "proc"))
304 wdt->mr |= AT91_WDT_WDRPROC;
305
306 if (of_property_read_bool(np, "atmel,disable")) {
307 wdt->mr |= AT91_WDT_WDDIS;
308 wdt->mr_mask &= AT91_WDT_WDDIS;
309 }
310
311 if (of_property_read_bool(np, "atmel,idle-halt"))
312 wdt->mr |= AT91_WDT_WDIDLEHLT;
313
314 if (of_property_read_bool(np, "atmel,dbg-halt"))
315 wdt->mr |= AT91_WDT_WDDBGHLT;
316
317 wdt->mr |= max | ((max - min) << 16);
318
319 return 0;
320}
321#else
322static inline int of_at91wdt_init(struct device_node *np, struct at91wdt *wdt)
323{
324 return 0;
325}
326#endif
327
328static int __init at91wdt_probe(struct platform_device *pdev)
329{
330 int err;
331 struct at91wdt *wdt;
332
333 wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
334 if (!wdt)
335 return -ENOMEM;
336
337 wdt->mr = (WDT_HW_TIMEOUT * 256) | AT91_WDT_WDRSTEN | AT91_WDT_WDD |
338 AT91_WDT_WDDBGHLT | AT91_WDT_WDIDLEHLT;
339 wdt->mr_mask = 0x3FFFFFFF;
340 wdt->nowayout = nowayout;
341 wdt->wdd.parent = &pdev->dev;
342 wdt->wdd.info = &at91_wdt_info;
343 wdt->wdd.ops = &at91_wdt_ops;
344 wdt->wdd.timeout = WDT_HEARTBEAT;
345 wdt->wdd.min_timeout = 1;
346 wdt->wdd.max_timeout = 0xFFFF;
347
348 wdt->base = devm_platform_ioremap_resource(pdev, 0);
349 if (IS_ERR(wdt->base))
350 return PTR_ERR(wdt->base);
351
352 wdt->sclk = devm_clk_get(&pdev->dev, NULL);
353 if (IS_ERR(wdt->sclk))
354 return PTR_ERR(wdt->sclk);
355
356 err = clk_prepare_enable(wdt->sclk);
357 if (err) {
358 dev_err(&pdev->dev, "Could not enable slow clock\n");
359 return err;
360 }
361
362 if (pdev->dev.of_node) {
363 err = of_at91wdt_init(pdev->dev.of_node, wdt);
364 if (err)
365 goto err_clk;
366 }
367
368 err = at91_wdt_init(pdev, wdt);
369 if (err)
370 goto err_clk;
371
372 platform_set_drvdata(pdev, wdt);
373
374 pr_info("enabled (heartbeat=%d sec, nowayout=%d)\n",
375 wdt->wdd.timeout, wdt->nowayout);
376
377 return 0;
378
379err_clk:
380 clk_disable_unprepare(wdt->sclk);
381
382 return err;
383}
384
385static int __exit at91wdt_remove(struct platform_device *pdev)
386{
387 struct at91wdt *wdt = platform_get_drvdata(pdev);
388 watchdog_unregister_device(&wdt->wdd);
389
390 pr_warn("I quit now, hardware will probably reboot!\n");
391 del_timer(&wdt->timer);
392 clk_disable_unprepare(wdt->sclk);
393
394 return 0;
395}
396
397#if defined(CONFIG_OF)
398static const struct of_device_id at91_wdt_dt_ids[] = {
399 { .compatible = "atmel,at91sam9260-wdt" },
400 { }
401};
402
403MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
404#endif
405
406static struct platform_driver at91wdt_driver = {
407 .remove = __exit_p(at91wdt_remove),
408 .driver = {
409 .name = "at91_wdt",
410 .of_match_table = of_match_ptr(at91_wdt_dt_ids),
411 },
412};
413
414module_platform_driver_probe(at91wdt_driver, at91wdt_probe);
415
416MODULE_AUTHOR("Renaud CERRATO <r.cerrato@til-technologies.fr>");
417MODULE_DESCRIPTION("Watchdog driver for Atmel AT91SAM9x processors");
418MODULE_LICENSE("GPL");
419
