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1/*
2 * drivers/char/watchdog/sp805-wdt.c
3 *
4 * Watchdog driver for ARM SP805 watchdog module
5 *
6 * Copyright (C) 2010 ST Microelectronics
7 * Viresh Kumar <viresh.linux@gmail.com>
8 *
9 * This file is licensed under the terms of the GNU General Public
10 * License version 2 or later. This program is licensed "as is" without any
11 * warranty of any kind, whether express or implied.
12 */
13
14#include <linux/device.h>
15#include <linux/resource.h>
16#include <linux/amba/bus.h>
17#include <linux/bitops.h>
18#include <linux/clk.h>
19#include <linux/init.h>
20#include <linux/io.h>
21#include <linux/ioport.h>
22#include <linux/kernel.h>
23#include <linux/math64.h>
24#include <linux/module.h>
25#include <linux/moduleparam.h>
26#include <linux/pm.h>
27#include <linux/slab.h>
28#include <linux/spinlock.h>
29#include <linux/types.h>
30#include <linux/watchdog.h>
31
32/* default timeout in seconds */
33#define DEFAULT_TIMEOUT 60
34
35#define MODULE_NAME "sp805-wdt"
36
37/* watchdog register offsets and masks */
38#define WDTLOAD 0x000
39 #define LOAD_MIN 0x00000001
40 #define LOAD_MAX 0xFFFFFFFF
41#define WDTVALUE 0x004
42#define WDTCONTROL 0x008
43 /* control register masks */
44 #define INT_ENABLE (1 << 0)
45 #define RESET_ENABLE (1 << 1)
46#define WDTINTCLR 0x00C
47#define WDTRIS 0x010
48#define WDTMIS 0x014
49 #define INT_MASK (1 << 0)
50#define WDTLOCK 0xC00
51 #define UNLOCK 0x1ACCE551
52 #define LOCK 0x00000001
53
54/**
55 * struct sp805_wdt: sp805 wdt device structure
56 * @wdd: instance of struct watchdog_device
57 * @lock: spin lock protecting dev structure and io access
58 * @base: base address of wdt
59 * @clk: clock structure of wdt
60 * @adev: amba device structure of wdt
61 * @status: current status of wdt
62 * @load_val: load value to be set for current timeout
63 * @timeout: current programmed timeout
64 */
65struct sp805_wdt {
66 struct watchdog_device wdd;
67 spinlock_t lock;
68 void __iomem *base;
69 struct clk *clk;
70 struct amba_device *adev;
71 unsigned int load_val;
72 unsigned int timeout;
73};
74
75static bool nowayout = WATCHDOG_NOWAYOUT;
76module_param(nowayout, bool, 0);
77MODULE_PARM_DESC(nowayout,
78 "Set to 1 to keep watchdog running after device release");
79
80/* This routine finds load value that will reset system in required timout */
81static int wdt_setload(struct watchdog_device *wdd, unsigned int timeout)
82{
83 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
84 u64 load, rate;
85
86 rate = clk_get_rate(wdt->clk);
87
88 /*
89 * sp805 runs counter with given value twice, after the end of first
90 * counter it gives an interrupt and then starts counter again. If
91 * interrupt already occurred then it resets the system. This is why
92 * load is half of what should be required.
93 */
94 load = div_u64(rate, 2) * timeout - 1;
95
96 load = (load > LOAD_MAX) ? LOAD_MAX : load;
97 load = (load < LOAD_MIN) ? LOAD_MIN : load;
98
99 spin_lock(&wdt->lock);
100 wdt->load_val = load;
101 /* roundup timeout to closest positive integer value */
102 wdt->timeout = div_u64((load + 1) * 2 + (rate / 2), rate);
103 spin_unlock(&wdt->lock);
104
105 return 0;
106}
107
108/* returns number of seconds left for reset to occur */
109static unsigned int wdt_timeleft(struct watchdog_device *wdd)
110{
111 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
112 u64 load, rate;
113
114 rate = clk_get_rate(wdt->clk);
115
116 spin_lock(&wdt->lock);
117 load = readl_relaxed(wdt->base + WDTVALUE);
118
119 /*If the interrupt is inactive then time left is WDTValue + WDTLoad. */
120 if (!(readl_relaxed(wdt->base + WDTRIS) & INT_MASK))
121 load += wdt->load_val + 1;
122 spin_unlock(&wdt->lock);
123
124 return div_u64(load, rate);
125}
126
127static int wdt_config(struct watchdog_device *wdd, bool ping)
128{
129 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
130 int ret;
131
132 if (!ping) {
133 ret = clk_prepare(wdt->clk);
134 if (ret) {
135 dev_err(&wdt->adev->dev, "clock prepare fail");
136 return ret;
137 }
138
139 ret = clk_enable(wdt->clk);
140 if (ret) {
141 dev_err(&wdt->adev->dev, "clock enable fail");
142 clk_unprepare(wdt->clk);
143 return ret;
144 }
145 }
146
147 spin_lock(&wdt->lock);
148
149 writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
150 writel_relaxed(wdt->load_val, wdt->base + WDTLOAD);
151
152 if (!ping) {
153 writel_relaxed(INT_MASK, wdt->base + WDTINTCLR);
154 writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base +
155 WDTCONTROL);
156 }
157
158 writel_relaxed(LOCK, wdt->base + WDTLOCK);
159
160 /* Flush posted writes. */
161 readl_relaxed(wdt->base + WDTLOCK);
162 spin_unlock(&wdt->lock);
163
164 return 0;
165}
166
167static int wdt_ping(struct watchdog_device *wdd)
168{
169 return wdt_config(wdd, true);
170}
171
172/* enables watchdog timers reset */
173static int wdt_enable(struct watchdog_device *wdd)
174{
175 return wdt_config(wdd, false);
176}
177
178/* disables watchdog timers reset */
179static int wdt_disable(struct watchdog_device *wdd)
180{
181 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
182
183 spin_lock(&wdt->lock);
184
185 writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
186 writel_relaxed(0, wdt->base + WDTCONTROL);
187 writel_relaxed(LOCK, wdt->base + WDTLOCK);
188
189 /* Flush posted writes. */
190 readl_relaxed(wdt->base + WDTLOCK);
191 spin_unlock(&wdt->lock);
192
193 clk_disable(wdt->clk);
194 clk_unprepare(wdt->clk);
195
196 return 0;
197}
198
199static const struct watchdog_info wdt_info = {
200 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
201 .identity = MODULE_NAME,
202};
203
204static const struct watchdog_ops wdt_ops = {
205 .owner = THIS_MODULE,
206 .start = wdt_enable,
207 .stop = wdt_disable,
208 .ping = wdt_ping,
209 .set_timeout = wdt_setload,
210 .get_timeleft = wdt_timeleft,
211};
212
213static int __devinit
214sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
215{
216 struct sp805_wdt *wdt;
217 int ret = 0;
218
219 if (!devm_request_mem_region(&adev->dev, adev->res.start,
220 resource_size(&adev->res), "sp805_wdt")) {
221 dev_warn(&adev->dev, "Failed to get memory region resource\n");
222 ret = -ENOENT;
223 goto err;
224 }
225
226 wdt = devm_kzalloc(&adev->dev, sizeof(*wdt), GFP_KERNEL);
227 if (!wdt) {
228 dev_warn(&adev->dev, "Kzalloc failed\n");
229 ret = -ENOMEM;
230 goto err;
231 }
232
233 wdt->base = devm_ioremap(&adev->dev, adev->res.start,
234 resource_size(&adev->res));
235 if (!wdt->base) {
236 ret = -ENOMEM;
237 dev_warn(&adev->dev, "ioremap fail\n");
238 goto err;
239 }
240
241 wdt->clk = clk_get(&adev->dev, NULL);
242 if (IS_ERR(wdt->clk)) {
243 dev_warn(&adev->dev, "Clock not found\n");
244 ret = PTR_ERR(wdt->clk);
245 goto err;
246 }
247
248 wdt->adev = adev;
249 wdt->wdd.info = &wdt_info;
250 wdt->wdd.ops = &wdt_ops;
251
252 spin_lock_init(&wdt->lock);
253 watchdog_set_nowayout(&wdt->wdd, nowayout);
254 watchdog_set_drvdata(&wdt->wdd, wdt);
255 wdt_setload(&wdt->wdd, DEFAULT_TIMEOUT);
256
257 ret = watchdog_register_device(&wdt->wdd);
258 if (ret) {
259 dev_err(&adev->dev, "watchdog_register_device() failed: %d\n",
260 ret);
261 goto err_register;
262 }
263 amba_set_drvdata(adev, wdt);
264
265 dev_info(&adev->dev, "registration successful\n");
266 return 0;
267
268err_register:
269 clk_put(wdt->clk);
270err:
271 dev_err(&adev->dev, "Probe Failed!!!\n");
272 return ret;
273}
274
275static int __devexit sp805_wdt_remove(struct amba_device *adev)
276{
277 struct sp805_wdt *wdt = amba_get_drvdata(adev);
278
279 watchdog_unregister_device(&wdt->wdd);
280 amba_set_drvdata(adev, NULL);
281 watchdog_set_drvdata(&wdt->wdd, NULL);
282 clk_put(wdt->clk);
283
284 return 0;
285}
286
287#ifdef CONFIG_PM
288static int sp805_wdt_suspend(struct device *dev)
289{
290 struct sp805_wdt *wdt = dev_get_drvdata(dev);
291
292 if (watchdog_active(&wdt->wdd))
293 return wdt_disable(&wdt->wdd);
294
295 return 0;
296}
297
298static int sp805_wdt_resume(struct device *dev)
299{
300 struct sp805_wdt *wdt = dev_get_drvdata(dev);
301
302 if (watchdog_active(&wdt->wdd))
303 return wdt_enable(&wdt->wdd);
304
305 return 0;
306}
307#endif /* CONFIG_PM */
308
309static SIMPLE_DEV_PM_OPS(sp805_wdt_dev_pm_ops, sp805_wdt_suspend,
310 sp805_wdt_resume);
311
312static struct amba_id sp805_wdt_ids[] = {
313 {
314 .id = 0x00141805,
315 .mask = 0x00ffffff,
316 },
317 { 0, 0 },
318};
319
320MODULE_DEVICE_TABLE(amba, sp805_wdt_ids);
321
322static struct amba_driver sp805_wdt_driver = {
323 .drv = {
324 .name = MODULE_NAME,
325 .pm = &sp805_wdt_dev_pm_ops,
326 },
327 .id_table = sp805_wdt_ids,
328 .probe = sp805_wdt_probe,
329 .remove = __devexit_p(sp805_wdt_remove),
330};
331
332module_amba_driver(sp805_wdt_driver);
333
334MODULE_AUTHOR("Viresh Kumar <viresh.linux@gmail.com>");
335MODULE_DESCRIPTION("ARM SP805 Watchdog Driver");
336MODULE_LICENSE("GPL");
1/*
2 * drivers/char/watchdog/sp805-wdt.c
3 *
4 * Watchdog driver for ARM SP805 watchdog module
5 *
6 * Copyright (C) 2010 ST Microelectronics
7 * Viresh Kumar <vireshk@kernel.org>
8 *
9 * This file is licensed under the terms of the GNU General Public
10 * License version 2 or later. This program is licensed "as is" without any
11 * warranty of any kind, whether express or implied.
12 */
13
14#include <linux/device.h>
15#include <linux/resource.h>
16#include <linux/amba/bus.h>
17#include <linux/bitops.h>
18#include <linux/clk.h>
19#include <linux/io.h>
20#include <linux/ioport.h>
21#include <linux/kernel.h>
22#include <linux/math64.h>
23#include <linux/module.h>
24#include <linux/moduleparam.h>
25#include <linux/pm.h>
26#include <linux/property.h>
27#include <linux/slab.h>
28#include <linux/spinlock.h>
29#include <linux/types.h>
30#include <linux/watchdog.h>
31
32/* default timeout in seconds */
33#define DEFAULT_TIMEOUT 60
34
35#define MODULE_NAME "sp805-wdt"
36
37/* watchdog register offsets and masks */
38#define WDTLOAD 0x000
39 #define LOAD_MIN 0x00000001
40 #define LOAD_MAX 0xFFFFFFFF
41#define WDTVALUE 0x004
42#define WDTCONTROL 0x008
43 /* control register masks */
44 #define INT_ENABLE (1 << 0)
45 #define RESET_ENABLE (1 << 1)
46 #define ENABLE_MASK (INT_ENABLE | RESET_ENABLE)
47#define WDTINTCLR 0x00C
48#define WDTRIS 0x010
49#define WDTMIS 0x014
50 #define INT_MASK (1 << 0)
51#define WDTLOCK 0xC00
52 #define UNLOCK 0x1ACCE551
53 #define LOCK 0x00000001
54
55/**
56 * struct sp805_wdt: sp805 wdt device structure
57 * @wdd: instance of struct watchdog_device
58 * @lock: spin lock protecting dev structure and io access
59 * @base: base address of wdt
60 * @clk: (optional) clock structure of wdt
61 * @rate: (optional) clock rate when provided via properties
62 * @adev: amba device structure of wdt
63 * @status: current status of wdt
64 * @load_val: load value to be set for current timeout
65 */
66struct sp805_wdt {
67 struct watchdog_device wdd;
68 spinlock_t lock;
69 void __iomem *base;
70 struct clk *clk;
71 u64 rate;
72 struct amba_device *adev;
73 unsigned int load_val;
74};
75
76static bool nowayout = WATCHDOG_NOWAYOUT;
77module_param(nowayout, bool, 0);
78MODULE_PARM_DESC(nowayout,
79 "Set to 1 to keep watchdog running after device release");
80
81/* returns true if wdt is running; otherwise returns false */
82static bool wdt_is_running(struct watchdog_device *wdd)
83{
84 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
85 u32 wdtcontrol = readl_relaxed(wdt->base + WDTCONTROL);
86
87 return (wdtcontrol & ENABLE_MASK) == ENABLE_MASK;
88}
89
90/* This routine finds load value that will reset system in required timout */
91static int wdt_setload(struct watchdog_device *wdd, unsigned int timeout)
92{
93 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
94 u64 load, rate;
95
96 rate = wdt->rate;
97
98 /*
99 * sp805 runs counter with given value twice, after the end of first
100 * counter it gives an interrupt and then starts counter again. If
101 * interrupt already occurred then it resets the system. This is why
102 * load is half of what should be required.
103 */
104 load = div_u64(rate, 2) * timeout - 1;
105
106 load = (load > LOAD_MAX) ? LOAD_MAX : load;
107 load = (load < LOAD_MIN) ? LOAD_MIN : load;
108
109 spin_lock(&wdt->lock);
110 wdt->load_val = load;
111 /* roundup timeout to closest positive integer value */
112 wdd->timeout = div_u64((load + 1) * 2 + (rate / 2), rate);
113 spin_unlock(&wdt->lock);
114
115 return 0;
116}
117
118/* returns number of seconds left for reset to occur */
119static unsigned int wdt_timeleft(struct watchdog_device *wdd)
120{
121 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
122 u64 load;
123
124 spin_lock(&wdt->lock);
125 load = readl_relaxed(wdt->base + WDTVALUE);
126
127 /*If the interrupt is inactive then time left is WDTValue + WDTLoad. */
128 if (!(readl_relaxed(wdt->base + WDTRIS) & INT_MASK))
129 load += wdt->load_val + 1;
130 spin_unlock(&wdt->lock);
131
132 return div_u64(load, wdt->rate);
133}
134
135static int
136wdt_restart(struct watchdog_device *wdd, unsigned long mode, void *cmd)
137{
138 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
139
140 writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
141 writel_relaxed(0, wdt->base + WDTCONTROL);
142 writel_relaxed(0, wdt->base + WDTLOAD);
143 writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base + WDTCONTROL);
144
145 /* Flush posted writes. */
146 readl_relaxed(wdt->base + WDTLOCK);
147
148 return 0;
149}
150
151static int wdt_config(struct watchdog_device *wdd, bool ping)
152{
153 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
154 int ret;
155
156 if (!ping) {
157
158 ret = clk_prepare_enable(wdt->clk);
159 if (ret) {
160 dev_err(&wdt->adev->dev, "clock enable fail");
161 return ret;
162 }
163 }
164
165 spin_lock(&wdt->lock);
166
167 writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
168 writel_relaxed(wdt->load_val, wdt->base + WDTLOAD);
169 writel_relaxed(INT_MASK, wdt->base + WDTINTCLR);
170
171 if (!ping)
172 writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base +
173 WDTCONTROL);
174
175 writel_relaxed(LOCK, wdt->base + WDTLOCK);
176
177 /* Flush posted writes. */
178 readl_relaxed(wdt->base + WDTLOCK);
179 spin_unlock(&wdt->lock);
180
181 return 0;
182}
183
184static int wdt_ping(struct watchdog_device *wdd)
185{
186 return wdt_config(wdd, true);
187}
188
189/* enables watchdog timers reset */
190static int wdt_enable(struct watchdog_device *wdd)
191{
192 return wdt_config(wdd, false);
193}
194
195/* disables watchdog timers reset */
196static int wdt_disable(struct watchdog_device *wdd)
197{
198 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
199
200 spin_lock(&wdt->lock);
201
202 writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
203 writel_relaxed(0, wdt->base + WDTCONTROL);
204 writel_relaxed(LOCK, wdt->base + WDTLOCK);
205
206 /* Flush posted writes. */
207 readl_relaxed(wdt->base + WDTLOCK);
208 spin_unlock(&wdt->lock);
209
210 clk_disable_unprepare(wdt->clk);
211
212 return 0;
213}
214
215static const struct watchdog_info wdt_info = {
216 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
217 .identity = MODULE_NAME,
218};
219
220static const struct watchdog_ops wdt_ops = {
221 .owner = THIS_MODULE,
222 .start = wdt_enable,
223 .stop = wdt_disable,
224 .ping = wdt_ping,
225 .set_timeout = wdt_setload,
226 .get_timeleft = wdt_timeleft,
227 .restart = wdt_restart,
228};
229
230static int
231sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
232{
233 struct sp805_wdt *wdt;
234 u64 rate = 0;
235 int ret = 0;
236
237 wdt = devm_kzalloc(&adev->dev, sizeof(*wdt), GFP_KERNEL);
238 if (!wdt) {
239 ret = -ENOMEM;
240 goto err;
241 }
242
243 wdt->base = devm_ioremap_resource(&adev->dev, &adev->res);
244 if (IS_ERR(wdt->base))
245 return PTR_ERR(wdt->base);
246
247 /*
248 * When driver probe with ACPI device, clock devices
249 * are not available, so watchdog rate get from
250 * clock-frequency property given in _DSD object.
251 */
252 device_property_read_u64(&adev->dev, "clock-frequency", &rate);
253
254 wdt->clk = devm_clk_get_optional(&adev->dev, NULL);
255 if (IS_ERR(wdt->clk))
256 return dev_err_probe(&adev->dev, PTR_ERR(wdt->clk), "Clock not found\n");
257
258 wdt->rate = clk_get_rate(wdt->clk);
259 if (!wdt->rate)
260 wdt->rate = rate;
261 if (!wdt->rate) {
262 dev_err(&adev->dev, "no clock-frequency property\n");
263 return -ENODEV;
264 }
265
266 wdt->adev = adev;
267 wdt->wdd.info = &wdt_info;
268 wdt->wdd.ops = &wdt_ops;
269 wdt->wdd.parent = &adev->dev;
270
271 spin_lock_init(&wdt->lock);
272 watchdog_set_nowayout(&wdt->wdd, nowayout);
273 watchdog_set_drvdata(&wdt->wdd, wdt);
274 watchdog_set_restart_priority(&wdt->wdd, 128);
275
276 /*
277 * If 'timeout-sec' devicetree property is specified, use that.
278 * Otherwise, use DEFAULT_TIMEOUT
279 */
280 wdt->wdd.timeout = DEFAULT_TIMEOUT;
281 watchdog_init_timeout(&wdt->wdd, 0, &adev->dev);
282 wdt_setload(&wdt->wdd, wdt->wdd.timeout);
283
284 /*
285 * If HW is already running, enable/reset the wdt and set the running
286 * bit to tell the wdt subsystem
287 */
288 if (wdt_is_running(&wdt->wdd)) {
289 wdt_enable(&wdt->wdd);
290 set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
291 }
292
293 watchdog_stop_on_reboot(&wdt->wdd);
294 ret = watchdog_register_device(&wdt->wdd);
295 if (ret)
296 goto err;
297 amba_set_drvdata(adev, wdt);
298
299 dev_info(&adev->dev, "registration successful\n");
300 return 0;
301
302err:
303 dev_err(&adev->dev, "Probe Failed!!!\n");
304 return ret;
305}
306
307static void sp805_wdt_remove(struct amba_device *adev)
308{
309 struct sp805_wdt *wdt = amba_get_drvdata(adev);
310
311 watchdog_unregister_device(&wdt->wdd);
312 watchdog_set_drvdata(&wdt->wdd, NULL);
313}
314
315static int __maybe_unused sp805_wdt_suspend(struct device *dev)
316{
317 struct sp805_wdt *wdt = dev_get_drvdata(dev);
318
319 if (watchdog_active(&wdt->wdd))
320 return wdt_disable(&wdt->wdd);
321
322 return 0;
323}
324
325static int __maybe_unused sp805_wdt_resume(struct device *dev)
326{
327 struct sp805_wdt *wdt = dev_get_drvdata(dev);
328
329 if (watchdog_active(&wdt->wdd))
330 return wdt_enable(&wdt->wdd);
331
332 return 0;
333}
334
335static SIMPLE_DEV_PM_OPS(sp805_wdt_dev_pm_ops, sp805_wdt_suspend,
336 sp805_wdt_resume);
337
338static const struct amba_id sp805_wdt_ids[] = {
339 {
340 .id = 0x00141805,
341 .mask = 0x00ffffff,
342 },
343 { 0, 0 },
344};
345
346MODULE_DEVICE_TABLE(amba, sp805_wdt_ids);
347
348static struct amba_driver sp805_wdt_driver = {
349 .drv = {
350 .name = MODULE_NAME,
351 .pm = &sp805_wdt_dev_pm_ops,
352 },
353 .id_table = sp805_wdt_ids,
354 .probe = sp805_wdt_probe,
355 .remove = sp805_wdt_remove,
356};
357
358module_amba_driver(sp805_wdt_driver);
359
360MODULE_AUTHOR("Viresh Kumar <vireshk@kernel.org>");
361MODULE_DESCRIPTION("ARM SP805 Watchdog Driver");
362MODULE_LICENSE("GPL");