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14#include <linux/acpi.h>
15#include <linux/device.h>
16#include <linux/resource.h>
17#include <linux/amba/bus.h>
18#include <linux/bitops.h>
19#include <linux/clk.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/of.h>
27#include <linux/pm.h>
28#include <linux/slab.h>
29#include <linux/spinlock.h>
30#include <linux/types.h>
31#include <linux/watchdog.h>
32
33
34#define DEFAULT_TIMEOUT 60
35
36#define MODULE_NAME "sp805-wdt"
37
38
39#define WDTLOAD 0x000
40 #define LOAD_MIN 0x00000001
41 #define LOAD_MAX 0xFFFFFFFF
42#define WDTVALUE 0x004
43#define WDTCONTROL 0x008
44
45 #define INT_ENABLE (1 << 0)
46 #define RESET_ENABLE (1 << 1)
47 #define ENABLE_MASK (INT_ENABLE | RESET_ENABLE)
48#define WDTINTCLR 0x00C
49#define WDTRIS 0x010
50#define WDTMIS 0x014
51 #define INT_MASK (1 << 0)
52#define WDTLOCK 0xC00
53 #define UNLOCK 0x1ACCE551
54 #define LOCK 0x00000001
55
56
57
58
59
60
61
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63
64
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
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
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
100
101
102
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
112 wdd->timeout = div_u64((load + 1) * 2 + (rate / 2), rate);
113 spin_unlock(&wdt->lock);
114
115 return 0;
116}
117
118
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
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
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
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
190static int wdt_enable(struct watchdog_device *wdd)
191{
192 return wdt_config(wdd, false);
193}
194
195
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
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 int ret = 0;
235
236 wdt = devm_kzalloc(&adev->dev, sizeof(*wdt), GFP_KERNEL);
237 if (!wdt) {
238 ret = -ENOMEM;
239 goto err;
240 }
241
242 wdt->base = devm_ioremap_resource(&adev->dev, &adev->res);
243 if (IS_ERR(wdt->base))
244 return PTR_ERR(wdt->base);
245
246 if (adev->dev.of_node) {
247 wdt->clk = devm_clk_get(&adev->dev, NULL);
248 if (IS_ERR(wdt->clk)) {
249 dev_err(&adev->dev, "Clock not found\n");
250 return PTR_ERR(wdt->clk);
251 }
252 wdt->rate = clk_get_rate(wdt->clk);
253 } else if (has_acpi_companion(&adev->dev)) {
254
255
256
257
258
259 device_property_read_u64(&adev->dev, "clock-frequency",
260 &wdt->rate);
261 if (!wdt->rate) {
262 dev_err(&adev->dev, "no clock-frequency property\n");
263 return -ENODEV;
264 }
265 }
266
267 wdt->adev = adev;
268 wdt->wdd.info = &wdt_info;
269 wdt->wdd.ops = &wdt_ops;
270 wdt->wdd.parent = &adev->dev;
271
272 spin_lock_init(&wdt->lock);
273 watchdog_set_nowayout(&wdt->wdd, nowayout);
274 watchdog_set_drvdata(&wdt->wdd, wdt);
275 watchdog_set_restart_priority(&wdt->wdd, 128);
276
277
278
279
280
281 wdt->wdd.timeout = DEFAULT_TIMEOUT;
282 watchdog_init_timeout(&wdt->wdd, 0, &adev->dev);
283 wdt_setload(&wdt->wdd, wdt->wdd.timeout);
284
285
286
287
288
289 if (wdt_is_running(&wdt->wdd)) {
290 wdt_enable(&wdt->wdd);
291 set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
292 }
293
294 watchdog_stop_on_reboot(&wdt->wdd);
295 ret = watchdog_register_device(&wdt->wdd);
296 if (ret)
297 goto err;
298 amba_set_drvdata(adev, wdt);
299
300 dev_info(&adev->dev, "registration successful\n");
301 return 0;
302
303err:
304 dev_err(&adev->dev, "Probe Failed!!!\n");
305 return ret;
306}
307
308static int sp805_wdt_remove(struct amba_device *adev)
309{
310 struct sp805_wdt *wdt = amba_get_drvdata(adev);
311
312 watchdog_unregister_device(&wdt->wdd);
313 watchdog_set_drvdata(&wdt->wdd, NULL);
314
315 return 0;
316}
317
318static int __maybe_unused sp805_wdt_suspend(struct device *dev)
319{
320 struct sp805_wdt *wdt = dev_get_drvdata(dev);
321
322 if (watchdog_active(&wdt->wdd))
323 return wdt_disable(&wdt->wdd);
324
325 return 0;
326}
327
328static int __maybe_unused sp805_wdt_resume(struct device *dev)
329{
330 struct sp805_wdt *wdt = dev_get_drvdata(dev);
331
332 if (watchdog_active(&wdt->wdd))
333 return wdt_enable(&wdt->wdd);
334
335 return 0;
336}
337
338static SIMPLE_DEV_PM_OPS(sp805_wdt_dev_pm_ops, sp805_wdt_suspend,
339 sp805_wdt_resume);
340
341static const struct amba_id sp805_wdt_ids[] = {
342 {
343 .id = 0x00141805,
344 .mask = 0x00ffffff,
345 },
346 { 0, 0 },
347};
348
349MODULE_DEVICE_TABLE(amba, sp805_wdt_ids);
350
351static struct amba_driver sp805_wdt_driver = {
352 .drv = {
353 .name = MODULE_NAME,
354 .pm = &sp805_wdt_dev_pm_ops,
355 },
356 .id_table = sp805_wdt_ids,
357 .probe = sp805_wdt_probe,
358 .remove = sp805_wdt_remove,
359};
360
361module_amba_driver(sp805_wdt_driver);
362
363MODULE_AUTHOR("Viresh Kumar <vireshk@kernel.org>");
364MODULE_DESCRIPTION("ARM SP805 Watchdog Driver");
365MODULE_LICENSE("GPL");
366