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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/slab.h>
27#include <linux/spinlock.h>
28#include <linux/types.h>
29#include <linux/watchdog.h>
30
31
32#define DEFAULT_TIMEOUT 60
33
34#define MODULE_NAME "sp805-wdt"
35
36
37#define WDTLOAD 0x000
38 #define LOAD_MIN 0x00000001
39 #define LOAD_MAX 0xFFFFFFFF
40#define WDTVALUE 0x004
41#define WDTCONTROL 0x008
42
43 #define INT_ENABLE (1 << 0)
44 #define RESET_ENABLE (1 << 1)
45#define WDTINTCLR 0x00C
46#define WDTRIS 0x010
47#define WDTMIS 0x014
48 #define INT_MASK (1 << 0)
49#define WDTLOCK 0xC00
50 #define UNLOCK 0x1ACCE551
51 #define LOCK 0x00000001
52
53
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61
62
63struct sp805_wdt {
64 struct watchdog_device wdd;
65 spinlock_t lock;
66 void __iomem *base;
67 struct clk *clk;
68 struct amba_device *adev;
69 unsigned int load_val;
70};
71
72static bool nowayout = WATCHDOG_NOWAYOUT;
73module_param(nowayout, bool, 0);
74MODULE_PARM_DESC(nowayout,
75 "Set to 1 to keep watchdog running after device release");
76
77
78static int wdt_setload(struct watchdog_device *wdd, unsigned int timeout)
79{
80 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
81 u64 load, rate;
82
83 rate = clk_get_rate(wdt->clk);
84
85
86
87
88
89
90
91 load = div_u64(rate, 2) * timeout - 1;
92
93 load = (load > LOAD_MAX) ? LOAD_MAX : load;
94 load = (load < LOAD_MIN) ? LOAD_MIN : load;
95
96 spin_lock(&wdt->lock);
97 wdt->load_val = load;
98
99 wdd->timeout = div_u64((load + 1) * 2 + (rate / 2), rate);
100 spin_unlock(&wdt->lock);
101
102 return 0;
103}
104
105
106static unsigned int wdt_timeleft(struct watchdog_device *wdd)
107{
108 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
109 u64 load, rate;
110
111 rate = clk_get_rate(wdt->clk);
112
113 spin_lock(&wdt->lock);
114 load = readl_relaxed(wdt->base + WDTVALUE);
115
116
117 if (!(readl_relaxed(wdt->base + WDTRIS) & INT_MASK))
118 load += wdt->load_val + 1;
119 spin_unlock(&wdt->lock);
120
121 return div_u64(load, rate);
122}
123
124static int wdt_config(struct watchdog_device *wdd, bool ping)
125{
126 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
127 int ret;
128
129 if (!ping) {
130
131 ret = clk_prepare_enable(wdt->clk);
132 if (ret) {
133 dev_err(&wdt->adev->dev, "clock enable fail");
134 return ret;
135 }
136 }
137
138 spin_lock(&wdt->lock);
139
140 writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
141 writel_relaxed(wdt->load_val, wdt->base + WDTLOAD);
142
143 if (!ping) {
144 writel_relaxed(INT_MASK, wdt->base + WDTINTCLR);
145 writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base +
146 WDTCONTROL);
147 }
148
149 writel_relaxed(LOCK, wdt->base + WDTLOCK);
150
151
152 readl_relaxed(wdt->base + WDTLOCK);
153 spin_unlock(&wdt->lock);
154
155 return 0;
156}
157
158static int wdt_ping(struct watchdog_device *wdd)
159{
160 return wdt_config(wdd, true);
161}
162
163
164static int wdt_enable(struct watchdog_device *wdd)
165{
166 return wdt_config(wdd, false);
167}
168
169
170static int wdt_disable(struct watchdog_device *wdd)
171{
172 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
173
174 spin_lock(&wdt->lock);
175
176 writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
177 writel_relaxed(0, wdt->base + WDTCONTROL);
178 writel_relaxed(LOCK, wdt->base + WDTLOCK);
179
180
181 readl_relaxed(wdt->base + WDTLOCK);
182 spin_unlock(&wdt->lock);
183
184 clk_disable_unprepare(wdt->clk);
185
186 return 0;
187}
188
189static const struct watchdog_info wdt_info = {
190 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
191 .identity = MODULE_NAME,
192};
193
194static const struct watchdog_ops wdt_ops = {
195 .owner = THIS_MODULE,
196 .start = wdt_enable,
197 .stop = wdt_disable,
198 .ping = wdt_ping,
199 .set_timeout = wdt_setload,
200 .get_timeleft = wdt_timeleft,
201};
202
203static int
204sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
205{
206 struct sp805_wdt *wdt;
207 int ret = 0;
208
209 wdt = devm_kzalloc(&adev->dev, sizeof(*wdt), GFP_KERNEL);
210 if (!wdt) {
211 ret = -ENOMEM;
212 goto err;
213 }
214
215 wdt->base = devm_ioremap_resource(&adev->dev, &adev->res);
216 if (IS_ERR(wdt->base))
217 return PTR_ERR(wdt->base);
218
219 wdt->clk = devm_clk_get(&adev->dev, NULL);
220 if (IS_ERR(wdt->clk)) {
221 dev_warn(&adev->dev, "Clock not found\n");
222 ret = PTR_ERR(wdt->clk);
223 goto err;
224 }
225
226 wdt->adev = adev;
227 wdt->wdd.info = &wdt_info;
228 wdt->wdd.ops = &wdt_ops;
229 wdt->wdd.parent = &adev->dev;
230
231 spin_lock_init(&wdt->lock);
232 watchdog_set_nowayout(&wdt->wdd, nowayout);
233 watchdog_set_drvdata(&wdt->wdd, wdt);
234 wdt_setload(&wdt->wdd, DEFAULT_TIMEOUT);
235
236 ret = watchdog_register_device(&wdt->wdd);
237 if (ret) {
238 dev_err(&adev->dev, "watchdog_register_device() failed: %d\n",
239 ret);
240 goto err;
241 }
242 amba_set_drvdata(adev, wdt);
243
244 dev_info(&adev->dev, "registration successful\n");
245 return 0;
246
247err:
248 dev_err(&adev->dev, "Probe Failed!!!\n");
249 return ret;
250}
251
252static int sp805_wdt_remove(struct amba_device *adev)
253{
254 struct sp805_wdt *wdt = amba_get_drvdata(adev);
255
256 watchdog_unregister_device(&wdt->wdd);
257 watchdog_set_drvdata(&wdt->wdd, NULL);
258
259 return 0;
260}
261
262static int __maybe_unused sp805_wdt_suspend(struct device *dev)
263{
264 struct sp805_wdt *wdt = dev_get_drvdata(dev);
265
266 if (watchdog_active(&wdt->wdd))
267 return wdt_disable(&wdt->wdd);
268
269 return 0;
270}
271
272static int __maybe_unused sp805_wdt_resume(struct device *dev)
273{
274 struct sp805_wdt *wdt = dev_get_drvdata(dev);
275
276 if (watchdog_active(&wdt->wdd))
277 return wdt_enable(&wdt->wdd);
278
279 return 0;
280}
281
282static SIMPLE_DEV_PM_OPS(sp805_wdt_dev_pm_ops, sp805_wdt_suspend,
283 sp805_wdt_resume);
284
285static struct amba_id sp805_wdt_ids[] = {
286 {
287 .id = 0x00141805,
288 .mask = 0x00ffffff,
289 },
290 { 0, 0 },
291};
292
293MODULE_DEVICE_TABLE(amba, sp805_wdt_ids);
294
295static struct amba_driver sp805_wdt_driver = {
296 .drv = {
297 .name = MODULE_NAME,
298 .pm = &sp805_wdt_dev_pm_ops,
299 },
300 .id_table = sp805_wdt_ids,
301 .probe = sp805_wdt_probe,
302 .remove = sp805_wdt_remove,
303};
304
305module_amba_driver(sp805_wdt_driver);
306
307MODULE_AUTHOR("Viresh Kumar <vireshk@kernel.org>");
308MODULE_DESCRIPTION("ARM SP805 Watchdog Driver");
309MODULE_LICENSE("GPL");
310