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8#include <linux/delay.h>
9#include <linux/interrupt.h>
10#include <linux/io.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/of.h>
14#include <linux/of_device.h>
15#include <linux/of_irq.h>
16#include <linux/platform_device.h>
17#include <linux/reboot.h>
18#include <linux/watchdog.h>
19
20#include "at91sam9_wdt.h"
21
22
23#define MIN_WDT_TIMEOUT 1
24#define MAX_WDT_TIMEOUT 16
25#define WDT_DEFAULT_TIMEOUT MAX_WDT_TIMEOUT
26
27#define WDT_SEC2TICKS(s) ((s) ? (((s) << 8) - 1) : 0)
28
29struct sama5d4_wdt {
30 struct watchdog_device wdd;
31 void __iomem *reg_base;
32 u32 mr;
33 u32 ir;
34 unsigned long last_ping;
35 bool need_irq;
36 bool sam9x60_support;
37};
38
39static int wdt_timeout;
40static bool nowayout = WATCHDOG_NOWAYOUT;
41
42module_param(wdt_timeout, int, 0);
43MODULE_PARM_DESC(wdt_timeout,
44 "Watchdog timeout in seconds. (default = "
45 __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
46
47module_param(nowayout, bool, 0);
48MODULE_PARM_DESC(nowayout,
49 "Watchdog cannot be stopped once started (default="
50 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
51
52#define wdt_enabled (!(wdt->mr & AT91_WDT_WDDIS))
53
54#define wdt_read(wdt, field) \
55 readl_relaxed((wdt)->reg_base + (field))
56
57
58#define WDT_DELAY usecs_to_jiffies(123)
59
60static void wdt_write(struct sama5d4_wdt *wdt, u32 field, u32 val)
61{
62
63
64
65
66
67 while (time_before(jiffies, wdt->last_ping + WDT_DELAY))
68 usleep_range(30, 125);
69 writel_relaxed(val, wdt->reg_base + field);
70 wdt->last_ping = jiffies;
71}
72
73static void wdt_write_nosleep(struct sama5d4_wdt *wdt, u32 field, u32 val)
74{
75 if (time_before(jiffies, wdt->last_ping + WDT_DELAY))
76 udelay(123);
77 writel_relaxed(val, wdt->reg_base + field);
78 wdt->last_ping = jiffies;
79}
80
81static int sama5d4_wdt_start(struct watchdog_device *wdd)
82{
83 struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
84
85 if (wdt->sam9x60_support) {
86 writel_relaxed(wdt->ir, wdt->reg_base + AT91_SAM9X60_IER);
87 wdt->mr &= ~AT91_SAM9X60_WDDIS;
88 } else {
89 wdt->mr &= ~AT91_WDT_WDDIS;
90 }
91 wdt_write(wdt, AT91_WDT_MR, wdt->mr);
92
93 return 0;
94}
95
96static int sama5d4_wdt_stop(struct watchdog_device *wdd)
97{
98 struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
99
100 if (wdt->sam9x60_support) {
101 writel_relaxed(wdt->ir, wdt->reg_base + AT91_SAM9X60_IDR);
102 wdt->mr |= AT91_SAM9X60_WDDIS;
103 } else {
104 wdt->mr |= AT91_WDT_WDDIS;
105 }
106 wdt_write(wdt, AT91_WDT_MR, wdt->mr);
107
108 return 0;
109}
110
111static int sama5d4_wdt_ping(struct watchdog_device *wdd)
112{
113 struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
114
115 wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
116
117 return 0;
118}
119
120static int sama5d4_wdt_set_timeout(struct watchdog_device *wdd,
121 unsigned int timeout)
122{
123 struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
124 u32 value = WDT_SEC2TICKS(timeout);
125
126 if (wdt->sam9x60_support) {
127 wdt_write(wdt, AT91_SAM9X60_WLR,
128 AT91_SAM9X60_SET_COUNTER(value));
129
130 wdd->timeout = timeout;
131 return 0;
132 }
133
134 wdt->mr &= ~AT91_WDT_WDV;
135 wdt->mr |= AT91_WDT_SET_WDV(value);
136
137
138
139
140
141
142
143
144 if (wdt_enabled)
145 wdt_write(wdt, AT91_WDT_MR, wdt->mr & ~AT91_WDT_WDDIS);
146
147 wdd->timeout = timeout;
148
149 return 0;
150}
151
152static const struct watchdog_info sama5d4_wdt_info = {
153 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
154 .identity = "Atmel SAMA5D4 Watchdog",
155};
156
157static const struct watchdog_ops sama5d4_wdt_ops = {
158 .owner = THIS_MODULE,
159 .start = sama5d4_wdt_start,
160 .stop = sama5d4_wdt_stop,
161 .ping = sama5d4_wdt_ping,
162 .set_timeout = sama5d4_wdt_set_timeout,
163};
164
165static irqreturn_t sama5d4_wdt_irq_handler(int irq, void *dev_id)
166{
167 struct sama5d4_wdt *wdt = platform_get_drvdata(dev_id);
168 u32 reg;
169
170 if (wdt->sam9x60_support)
171 reg = wdt_read(wdt, AT91_SAM9X60_ISR);
172 else
173 reg = wdt_read(wdt, AT91_WDT_SR);
174
175 if (reg) {
176 pr_crit("Atmel Watchdog Software Reset\n");
177 emergency_restart();
178 pr_crit("Reboot didn't succeed\n");
179 }
180
181 return IRQ_HANDLED;
182}
183
184static int of_sama5d4_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt)
185{
186 const char *tmp;
187
188 if (wdt->sam9x60_support)
189 wdt->mr = AT91_SAM9X60_WDDIS;
190 else
191 wdt->mr = AT91_WDT_WDDIS;
192
193 if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) &&
194 !strcmp(tmp, "software"))
195 wdt->need_irq = true;
196
197 if (of_property_read_bool(np, "atmel,idle-halt"))
198 wdt->mr |= AT91_WDT_WDIDLEHLT;
199
200 if (of_property_read_bool(np, "atmel,dbg-halt"))
201 wdt->mr |= AT91_WDT_WDDBGHLT;
202
203 return 0;
204}
205
206static int sama5d4_wdt_init(struct sama5d4_wdt *wdt)
207{
208 u32 reg, val;
209
210 val = WDT_SEC2TICKS(WDT_DEFAULT_TIMEOUT);
211
212
213
214
215
216
217 if (!wdt_enabled) {
218 reg = wdt_read(wdt, AT91_WDT_MR);
219 if (wdt->sam9x60_support && (!(reg & AT91_SAM9X60_WDDIS)))
220 wdt_write_nosleep(wdt, AT91_WDT_MR,
221 reg | AT91_SAM9X60_WDDIS);
222 else if (!wdt->sam9x60_support &&
223 (!(reg & AT91_WDT_WDDIS)))
224 wdt_write_nosleep(wdt, AT91_WDT_MR,
225 reg | AT91_WDT_WDDIS);
226 }
227
228 if (wdt->sam9x60_support) {
229 if (wdt->need_irq)
230 wdt->ir = AT91_SAM9X60_PERINT;
231 else
232 wdt->mr |= AT91_SAM9X60_PERIODRST;
233
234 wdt_write(wdt, AT91_SAM9X60_IER, wdt->ir);
235 wdt_write(wdt, AT91_SAM9X60_WLR, AT91_SAM9X60_SET_COUNTER(val));
236 } else {
237 wdt->mr |= AT91_WDT_SET_WDD(WDT_SEC2TICKS(MAX_WDT_TIMEOUT));
238 wdt->mr |= AT91_WDT_SET_WDV(val);
239
240 if (wdt->need_irq)
241 wdt->mr |= AT91_WDT_WDFIEN;
242 else
243 wdt->mr |= AT91_WDT_WDRSTEN;
244 }
245
246 wdt_write_nosleep(wdt, AT91_WDT_MR, wdt->mr);
247
248 return 0;
249}
250
251static int sama5d4_wdt_probe(struct platform_device *pdev)
252{
253 struct device *dev = &pdev->dev;
254 struct watchdog_device *wdd;
255 struct sama5d4_wdt *wdt;
256 void __iomem *regs;
257 u32 irq = 0;
258 int ret;
259
260 wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
261 if (!wdt)
262 return -ENOMEM;
263
264 wdd = &wdt->wdd;
265 wdd->timeout = WDT_DEFAULT_TIMEOUT;
266 wdd->info = &sama5d4_wdt_info;
267 wdd->ops = &sama5d4_wdt_ops;
268 wdd->min_timeout = MIN_WDT_TIMEOUT;
269 wdd->max_timeout = MAX_WDT_TIMEOUT;
270 wdt->last_ping = jiffies;
271 wdt->sam9x60_support = of_device_is_compatible(dev->of_node,
272 "microchip,sam9x60-wdt");
273
274 watchdog_set_drvdata(wdd, wdt);
275
276 regs = devm_platform_ioremap_resource(pdev, 0);
277 if (IS_ERR(regs))
278 return PTR_ERR(regs);
279
280 wdt->reg_base = regs;
281
282 ret = of_sama5d4_wdt_init(dev->of_node, wdt);
283 if (ret)
284 return ret;
285
286 if (wdt->need_irq) {
287 irq = irq_of_parse_and_map(dev->of_node, 0);
288 if (!irq) {
289 dev_warn(dev, "failed to get IRQ from DT\n");
290 wdt->need_irq = false;
291 }
292 }
293
294 if (wdt->need_irq) {
295 ret = devm_request_irq(dev, irq, sama5d4_wdt_irq_handler,
296 IRQF_SHARED | IRQF_IRQPOLL |
297 IRQF_NO_SUSPEND, pdev->name, pdev);
298 if (ret) {
299 dev_err(dev, "cannot register interrupt handler\n");
300 return ret;
301 }
302 }
303
304 watchdog_init_timeout(wdd, wdt_timeout, dev);
305
306 ret = sama5d4_wdt_init(wdt);
307 if (ret)
308 return ret;
309
310 watchdog_set_nowayout(wdd, nowayout);
311
312 watchdog_stop_on_unregister(wdd);
313 ret = devm_watchdog_register_device(dev, wdd);
314 if (ret)
315 return ret;
316
317 platform_set_drvdata(pdev, wdt);
318
319 dev_info(dev, "initialized (timeout = %d sec, nowayout = %d)\n",
320 wdd->timeout, nowayout);
321
322 return 0;
323}
324
325static const struct of_device_id sama5d4_wdt_of_match[] = {
326 {
327 .compatible = "atmel,sama5d4-wdt",
328 },
329 {
330 .compatible = "microchip,sam9x60-wdt",
331 },
332 { }
333};
334MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match);
335
336#ifdef CONFIG_PM_SLEEP
337static int sama5d4_wdt_suspend_late(struct device *dev)
338{
339 struct sama5d4_wdt *wdt = dev_get_drvdata(dev);
340
341 if (watchdog_active(&wdt->wdd))
342 sama5d4_wdt_stop(&wdt->wdd);
343
344 return 0;
345}
346
347static int sama5d4_wdt_resume_early(struct device *dev)
348{
349 struct sama5d4_wdt *wdt = dev_get_drvdata(dev);
350
351
352
353
354
355
356 sama5d4_wdt_init(wdt);
357
358 if (watchdog_active(&wdt->wdd))
359 sama5d4_wdt_start(&wdt->wdd);
360
361 return 0;
362}
363#endif
364
365static const struct dev_pm_ops sama5d4_wdt_pm_ops = {
366 SET_LATE_SYSTEM_SLEEP_PM_OPS(sama5d4_wdt_suspend_late,
367 sama5d4_wdt_resume_early)
368};
369
370static struct platform_driver sama5d4_wdt_driver = {
371 .probe = sama5d4_wdt_probe,
372 .driver = {
373 .name = "sama5d4_wdt",
374 .pm = &sama5d4_wdt_pm_ops,
375 .of_match_table = sama5d4_wdt_of_match,
376 }
377};
378module_platform_driver(sama5d4_wdt_driver);
379
380MODULE_AUTHOR("Atmel Corporation");
381MODULE_DESCRIPTION("Atmel SAMA5D4 Watchdog Timer driver");
382MODULE_LICENSE("GPL v2");
383
