Commit | Line | Data |
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76534860 WY |
1 | /* |
2 | * Driver for Atmel SAMA5D4 Watchdog Timer | |
3 | * | |
4 | * Copyright (C) 2015 Atmel Corporation | |
5 | * | |
6 | * Licensed under GPLv2. | |
7 | */ | |
8 | ||
ddd6d240 | 9 | #include <linux/delay.h> |
76534860 WY |
10 | #include <linux/interrupt.h> |
11 | #include <linux/io.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/of.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 | /* minimum and maximum watchdog timeout, in seconds */ | |
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 | ||
29 | struct sama5d4_wdt { | |
30 | struct watchdog_device wdd; | |
31 | void __iomem *reg_base; | |
722ce635 | 32 | u32 mr; |
ddd6d240 | 33 | unsigned long last_ping; |
76534860 WY |
34 | }; |
35 | ||
36 | static int wdt_timeout = WDT_DEFAULT_TIMEOUT; | |
37 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
38 | ||
39 | module_param(wdt_timeout, int, 0); | |
40 | MODULE_PARM_DESC(wdt_timeout, | |
41 | "Watchdog timeout in seconds. (default = " | |
42 | __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")"); | |
43 | ||
44 | module_param(nowayout, bool, 0); | |
45 | MODULE_PARM_DESC(nowayout, | |
46 | "Watchdog cannot be stopped once started (default=" | |
47 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
48 | ||
015b5286 AB |
49 | #define wdt_enabled (!(wdt->mr & AT91_WDT_WDDIS)) |
50 | ||
76534860 WY |
51 | #define wdt_read(wdt, field) \ |
52 | readl_relaxed((wdt)->reg_base + (field)) | |
53 | ||
ddd6d240 AB |
54 | /* 4 slow clock periods is 4/32768 = 122.07µs*/ |
55 | #define WDT_DELAY usecs_to_jiffies(123) | |
56 | ||
57 | static void wdt_write(struct sama5d4_wdt *wdt, u32 field, u32 val) | |
58 | { | |
59 | /* | |
60 | * WDT_CR and WDT_MR must not be modified within three slow clock | |
61 | * periods following a restart of the watchdog performed by a write | |
62 | * access in WDT_CR. | |
63 | */ | |
64 | while (time_before(jiffies, wdt->last_ping + WDT_DELAY)) | |
65 | usleep_range(30, 125); | |
66 | writel_relaxed(val, wdt->reg_base + field); | |
67 | wdt->last_ping = jiffies; | |
68 | } | |
69 | ||
70 | static void wdt_write_nosleep(struct sama5d4_wdt *wdt, u32 field, u32 val) | |
71 | { | |
72 | if (time_before(jiffies, wdt->last_ping + WDT_DELAY)) | |
73 | udelay(123); | |
74 | writel_relaxed(val, wdt->reg_base + field); | |
75 | wdt->last_ping = jiffies; | |
76 | } | |
76534860 WY |
77 | |
78 | static int sama5d4_wdt_start(struct watchdog_device *wdd) | |
79 | { | |
80 | struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd); | |
76534860 | 81 | |
722ce635 AB |
82 | wdt->mr &= ~AT91_WDT_WDDIS; |
83 | wdt_write(wdt, AT91_WDT_MR, wdt->mr); | |
76534860 WY |
84 | |
85 | return 0; | |
86 | } | |
87 | ||
88 | static int sama5d4_wdt_stop(struct watchdog_device *wdd) | |
89 | { | |
90 | struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd); | |
76534860 | 91 | |
722ce635 AB |
92 | wdt->mr |= AT91_WDT_WDDIS; |
93 | wdt_write(wdt, AT91_WDT_MR, wdt->mr); | |
76534860 WY |
94 | |
95 | return 0; | |
96 | } | |
97 | ||
98 | static int sama5d4_wdt_ping(struct watchdog_device *wdd) | |
99 | { | |
100 | struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd); | |
101 | ||
102 | wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT); | |
103 | ||
104 | return 0; | |
105 | } | |
106 | ||
107 | static int sama5d4_wdt_set_timeout(struct watchdog_device *wdd, | |
108 | unsigned int timeout) | |
109 | { | |
110 | struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd); | |
111 | u32 value = WDT_SEC2TICKS(timeout); | |
76534860 | 112 | |
722ce635 AB |
113 | wdt->mr &= ~AT91_WDT_WDV; |
114 | wdt->mr &= ~AT91_WDT_WDD; | |
115 | wdt->mr |= AT91_WDT_SET_WDV(value); | |
116 | wdt->mr |= AT91_WDT_SET_WDD(value); | |
015b5286 AB |
117 | |
118 | /* | |
119 | * WDDIS has to be 0 when updating WDD/WDV. The datasheet states: When | |
120 | * setting the WDDIS bit, and while it is set, the fields WDV and WDD | |
121 | * must not be modified. | |
122 | * If the watchdog is enabled, then the timeout can be updated. Else, | |
123 | * wait that the user enables it. | |
124 | */ | |
125 | if (wdt_enabled) | |
126 | wdt_write(wdt, AT91_WDT_MR, wdt->mr & ~AT91_WDT_WDDIS); | |
76534860 WY |
127 | |
128 | wdd->timeout = timeout; | |
129 | ||
130 | return 0; | |
131 | } | |
132 | ||
133 | static const struct watchdog_info sama5d4_wdt_info = { | |
134 | .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, | |
135 | .identity = "Atmel SAMA5D4 Watchdog", | |
136 | }; | |
137 | ||
b893e344 | 138 | static const struct watchdog_ops sama5d4_wdt_ops = { |
76534860 WY |
139 | .owner = THIS_MODULE, |
140 | .start = sama5d4_wdt_start, | |
141 | .stop = sama5d4_wdt_stop, | |
142 | .ping = sama5d4_wdt_ping, | |
143 | .set_timeout = sama5d4_wdt_set_timeout, | |
144 | }; | |
145 | ||
146 | static irqreturn_t sama5d4_wdt_irq_handler(int irq, void *dev_id) | |
147 | { | |
148 | struct sama5d4_wdt *wdt = platform_get_drvdata(dev_id); | |
149 | ||
150 | if (wdt_read(wdt, AT91_WDT_SR)) { | |
151 | pr_crit("Atmel Watchdog Software Reset\n"); | |
152 | emergency_restart(); | |
153 | pr_crit("Reboot didn't succeed\n"); | |
154 | } | |
155 | ||
156 | return IRQ_HANDLED; | |
157 | } | |
158 | ||
159 | static int of_sama5d4_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt) | |
160 | { | |
161 | const char *tmp; | |
162 | ||
722ce635 | 163 | wdt->mr = AT91_WDT_WDDIS; |
76534860 WY |
164 | |
165 | if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) && | |
166 | !strcmp(tmp, "software")) | |
722ce635 | 167 | wdt->mr |= AT91_WDT_WDFIEN; |
76534860 | 168 | else |
722ce635 | 169 | wdt->mr |= AT91_WDT_WDRSTEN; |
76534860 WY |
170 | |
171 | if (of_property_read_bool(np, "atmel,idle-halt")) | |
722ce635 | 172 | wdt->mr |= AT91_WDT_WDIDLEHLT; |
76534860 WY |
173 | |
174 | if (of_property_read_bool(np, "atmel,dbg-halt")) | |
722ce635 | 175 | wdt->mr |= AT91_WDT_WDDBGHLT; |
76534860 WY |
176 | |
177 | return 0; | |
178 | } | |
179 | ||
180 | static int sama5d4_wdt_init(struct sama5d4_wdt *wdt) | |
181 | { | |
76534860 | 182 | u32 reg; |
76534860 | 183 | /* |
015b5286 AB |
184 | * When booting and resuming, the bootloader may have changed the |
185 | * watchdog configuration. | |
186 | * If the watchdog is already running, we can safely update it. | |
187 | * Else, we have to disable it properly. | |
76534860 | 188 | */ |
015b5286 | 189 | if (wdt_enabled) { |
ddd6d240 | 190 | wdt_write_nosleep(wdt, AT91_WDT_MR, wdt->mr); |
015b5286 AB |
191 | } else { |
192 | reg = wdt_read(wdt, AT91_WDT_MR); | |
193 | if (!(reg & AT91_WDT_WDDIS)) | |
ddd6d240 AB |
194 | wdt_write_nosleep(wdt, AT91_WDT_MR, |
195 | reg | AT91_WDT_WDDIS); | |
015b5286 | 196 | } |
76534860 WY |
197 | return 0; |
198 | } | |
199 | ||
200 | static int sama5d4_wdt_probe(struct platform_device *pdev) | |
201 | { | |
202 | struct watchdog_device *wdd; | |
203 | struct sama5d4_wdt *wdt; | |
204 | struct resource *res; | |
205 | void __iomem *regs; | |
206 | u32 irq = 0; | |
015b5286 | 207 | u32 timeout; |
76534860 WY |
208 | int ret; |
209 | ||
210 | wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); | |
211 | if (!wdt) | |
212 | return -ENOMEM; | |
213 | ||
214 | wdd = &wdt->wdd; | |
215 | wdd->timeout = wdt_timeout; | |
216 | wdd->info = &sama5d4_wdt_info; | |
217 | wdd->ops = &sama5d4_wdt_ops; | |
218 | wdd->min_timeout = MIN_WDT_TIMEOUT; | |
219 | wdd->max_timeout = MAX_WDT_TIMEOUT; | |
ddd6d240 | 220 | wdt->last_ping = jiffies; |
76534860 WY |
221 | |
222 | watchdog_set_drvdata(wdd, wdt); | |
223 | ||
224 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
225 | regs = devm_ioremap_resource(&pdev->dev, res); | |
226 | if (IS_ERR(regs)) | |
227 | return PTR_ERR(regs); | |
228 | ||
229 | wdt->reg_base = regs; | |
230 | ||
39bd56df AB |
231 | irq = irq_of_parse_and_map(pdev->dev.of_node, 0); |
232 | if (!irq) | |
233 | dev_warn(&pdev->dev, "failed to get IRQ from DT\n"); | |
76534860 | 234 | |
39bd56df AB |
235 | ret = of_sama5d4_wdt_init(pdev->dev.of_node, wdt); |
236 | if (ret) | |
237 | return ret; | |
76534860 | 238 | |
722ce635 | 239 | if ((wdt->mr & AT91_WDT_WDFIEN) && irq) { |
76534860 WY |
240 | ret = devm_request_irq(&pdev->dev, irq, sama5d4_wdt_irq_handler, |
241 | IRQF_SHARED | IRQF_IRQPOLL | | |
242 | IRQF_NO_SUSPEND, pdev->name, pdev); | |
243 | if (ret) { | |
244 | dev_err(&pdev->dev, | |
245 | "cannot register interrupt handler\n"); | |
246 | return ret; | |
247 | } | |
248 | } | |
249 | ||
250 | ret = watchdog_init_timeout(wdd, wdt_timeout, &pdev->dev); | |
251 | if (ret) { | |
252 | dev_err(&pdev->dev, "unable to set timeout value\n"); | |
253 | return ret; | |
254 | } | |
255 | ||
015b5286 AB |
256 | timeout = WDT_SEC2TICKS(wdd->timeout); |
257 | ||
258 | wdt->mr |= AT91_WDT_SET_WDD(timeout); | |
259 | wdt->mr |= AT91_WDT_SET_WDV(timeout); | |
260 | ||
76534860 WY |
261 | ret = sama5d4_wdt_init(wdt); |
262 | if (ret) | |
263 | return ret; | |
264 | ||
265 | watchdog_set_nowayout(wdd, nowayout); | |
266 | ||
267 | ret = watchdog_register_device(wdd); | |
268 | if (ret) { | |
269 | dev_err(&pdev->dev, "failed to register watchdog device\n"); | |
270 | return ret; | |
271 | } | |
272 | ||
273 | platform_set_drvdata(pdev, wdt); | |
274 | ||
275 | dev_info(&pdev->dev, "initialized (timeout = %d sec, nowayout = %d)\n", | |
276 | wdt_timeout, nowayout); | |
277 | ||
278 | return 0; | |
279 | } | |
280 | ||
281 | static int sama5d4_wdt_remove(struct platform_device *pdev) | |
282 | { | |
283 | struct sama5d4_wdt *wdt = platform_get_drvdata(pdev); | |
284 | ||
285 | sama5d4_wdt_stop(&wdt->wdd); | |
286 | ||
287 | watchdog_unregister_device(&wdt->wdd); | |
288 | ||
289 | return 0; | |
290 | } | |
291 | ||
292 | static const struct of_device_id sama5d4_wdt_of_match[] = { | |
293 | { .compatible = "atmel,sama5d4-wdt", }, | |
294 | { } | |
295 | }; | |
296 | MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match); | |
297 | ||
f2013532 AB |
298 | #ifdef CONFIG_PM_SLEEP |
299 | static int sama5d4_wdt_resume(struct device *dev) | |
300 | { | |
301 | struct sama5d4_wdt *wdt = dev_get_drvdata(dev); | |
302 | ||
5dca80f6 AB |
303 | /* |
304 | * FIXME: writing MR also pings the watchdog which may not be desired. | |
305 | * This should only be done when the registers are lost on suspend but | |
306 | * there is no way to get this information right now. | |
307 | */ | |
015b5286 | 308 | sama5d4_wdt_init(wdt); |
f2013532 AB |
309 | |
310 | return 0; | |
311 | } | |
312 | #endif | |
313 | ||
314 | static SIMPLE_DEV_PM_OPS(sama5d4_wdt_pm_ops, NULL, | |
315 | sama5d4_wdt_resume); | |
316 | ||
76534860 WY |
317 | static struct platform_driver sama5d4_wdt_driver = { |
318 | .probe = sama5d4_wdt_probe, | |
319 | .remove = sama5d4_wdt_remove, | |
320 | .driver = { | |
321 | .name = "sama5d4_wdt", | |
f2013532 | 322 | .pm = &sama5d4_wdt_pm_ops, |
76534860 WY |
323 | .of_match_table = sama5d4_wdt_of_match, |
324 | } | |
325 | }; | |
326 | module_platform_driver(sama5d4_wdt_driver); | |
327 | ||
328 | MODULE_AUTHOR("Atmel Corporation"); | |
329 | MODULE_DESCRIPTION("Atmel SAMA5D4 Watchdog Timer driver"); | |
330 | MODULE_LICENSE("GPL v2"); |