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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Spreadtrum watchdog driver
4 * Copyright (C) 2017 Spreadtrum - http://www.spreadtrum.com
5 */
6
7#include <linux/bitops.h>
8#include <linux/clk.h>
9#include <linux/device.h>
10#include <linux/err.h>
11#include <linux/interrupt.h>
12#include <linux/io.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/of.h>
16#include <linux/of_address.h>
17#include <linux/platform_device.h>
18#include <linux/watchdog.h>
19
20#define SPRD_WDT_LOAD_LOW 0x0
21#define SPRD_WDT_LOAD_HIGH 0x4
22#define SPRD_WDT_CTRL 0x8
23#define SPRD_WDT_INT_CLR 0xc
24#define SPRD_WDT_INT_RAW 0x10
25#define SPRD_WDT_INT_MSK 0x14
26#define SPRD_WDT_CNT_LOW 0x18
27#define SPRD_WDT_CNT_HIGH 0x1c
28#define SPRD_WDT_LOCK 0x20
29#define SPRD_WDT_IRQ_LOAD_LOW 0x2c
30#define SPRD_WDT_IRQ_LOAD_HIGH 0x30
31
32/* WDT_CTRL */
33#define SPRD_WDT_INT_EN_BIT BIT(0)
34#define SPRD_WDT_CNT_EN_BIT BIT(1)
35#define SPRD_WDT_NEW_VER_EN BIT(2)
36#define SPRD_WDT_RST_EN_BIT BIT(3)
37
38/* WDT_INT_CLR */
39#define SPRD_WDT_INT_CLEAR_BIT BIT(0)
40#define SPRD_WDT_RST_CLEAR_BIT BIT(3)
41
42/* WDT_INT_RAW */
43#define SPRD_WDT_INT_RAW_BIT BIT(0)
44#define SPRD_WDT_RST_RAW_BIT BIT(3)
45#define SPRD_WDT_LD_BUSY_BIT BIT(4)
46
47/* 1s equal to 32768 counter steps */
48#define SPRD_WDT_CNT_STEP 32768
49
50#define SPRD_WDT_UNLOCK_KEY 0xe551
51#define SPRD_WDT_MIN_TIMEOUT 3
52#define SPRD_WDT_MAX_TIMEOUT 60
53
54#define SPRD_WDT_CNT_HIGH_SHIFT 16
55#define SPRD_WDT_LOW_VALUE_MASK GENMASK(15, 0)
56#define SPRD_WDT_LOAD_TIMEOUT 1000
57
58struct sprd_wdt {
59 void __iomem *base;
60 struct watchdog_device wdd;
61 struct clk *enable;
62 struct clk *rtc_enable;
63 int irq;
64};
65
66static inline struct sprd_wdt *to_sprd_wdt(struct watchdog_device *wdd)
67{
68 return container_of(wdd, struct sprd_wdt, wdd);
69}
70
71static inline void sprd_wdt_lock(void __iomem *addr)
72{
73 writel_relaxed(0x0, addr + SPRD_WDT_LOCK);
74}
75
76static inline void sprd_wdt_unlock(void __iomem *addr)
77{
78 writel_relaxed(SPRD_WDT_UNLOCK_KEY, addr + SPRD_WDT_LOCK);
79}
80
81static irqreturn_t sprd_wdt_isr(int irq, void *dev_id)
82{
83 struct sprd_wdt *wdt = (struct sprd_wdt *)dev_id;
84
85 sprd_wdt_unlock(wdt->base);
86 writel_relaxed(SPRD_WDT_INT_CLEAR_BIT, wdt->base + SPRD_WDT_INT_CLR);
87 sprd_wdt_lock(wdt->base);
88 watchdog_notify_pretimeout(&wdt->wdd);
89 return IRQ_HANDLED;
90}
91
92static u32 sprd_wdt_get_cnt_value(struct sprd_wdt *wdt)
93{
94 u32 val;
95
96 val = readl_relaxed(wdt->base + SPRD_WDT_CNT_HIGH) <<
97 SPRD_WDT_CNT_HIGH_SHIFT;
98 val |= readl_relaxed(wdt->base + SPRD_WDT_CNT_LOW) &
99 SPRD_WDT_LOW_VALUE_MASK;
100
101 return val;
102}
103
104static int sprd_wdt_load_value(struct sprd_wdt *wdt, u32 timeout,
105 u32 pretimeout)
106{
107 u32 val, delay_cnt = 0;
108 u32 tmr_step = timeout * SPRD_WDT_CNT_STEP;
109 u32 prtmr_step = pretimeout * SPRD_WDT_CNT_STEP;
110
111 sprd_wdt_unlock(wdt->base);
112 writel_relaxed((tmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) &
113 SPRD_WDT_LOW_VALUE_MASK, wdt->base + SPRD_WDT_LOAD_HIGH);
114 writel_relaxed((tmr_step & SPRD_WDT_LOW_VALUE_MASK),
115 wdt->base + SPRD_WDT_LOAD_LOW);
116 writel_relaxed((prtmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) &
117 SPRD_WDT_LOW_VALUE_MASK,
118 wdt->base + SPRD_WDT_IRQ_LOAD_HIGH);
119 writel_relaxed(prtmr_step & SPRD_WDT_LOW_VALUE_MASK,
120 wdt->base + SPRD_WDT_IRQ_LOAD_LOW);
121 sprd_wdt_lock(wdt->base);
122
123 /*
124 * Waiting the load value operation done,
125 * it needs two or three RTC clock cycles.
126 */
127 do {
128 val = readl_relaxed(wdt->base + SPRD_WDT_INT_RAW);
129 if (!(val & SPRD_WDT_LD_BUSY_BIT))
130 break;
131
132 cpu_relax();
133 } while (delay_cnt++ < SPRD_WDT_LOAD_TIMEOUT);
134
135 if (delay_cnt >= SPRD_WDT_LOAD_TIMEOUT)
136 return -EBUSY;
137 return 0;
138}
139
140static int sprd_wdt_enable(struct sprd_wdt *wdt)
141{
142 u32 val;
143 int ret;
144
145 ret = clk_prepare_enable(wdt->enable);
146 if (ret)
147 return ret;
148 ret = clk_prepare_enable(wdt->rtc_enable);
149 if (ret) {
150 clk_disable_unprepare(wdt->enable);
151 return ret;
152 }
153
154 sprd_wdt_unlock(wdt->base);
155 val = readl_relaxed(wdt->base + SPRD_WDT_CTRL);
156 val |= SPRD_WDT_NEW_VER_EN;
157 writel_relaxed(val, wdt->base + SPRD_WDT_CTRL);
158 sprd_wdt_lock(wdt->base);
159 return 0;
160}
161
162static void sprd_wdt_disable(void *_data)
163{
164 struct sprd_wdt *wdt = _data;
165
166 sprd_wdt_unlock(wdt->base);
167 writel_relaxed(0x0, wdt->base + SPRD_WDT_CTRL);
168 sprd_wdt_lock(wdt->base);
169
170 clk_disable_unprepare(wdt->rtc_enable);
171 clk_disable_unprepare(wdt->enable);
172}
173
174static int sprd_wdt_start(struct watchdog_device *wdd)
175{
176 struct sprd_wdt *wdt = to_sprd_wdt(wdd);
177 u32 val;
178 int ret;
179
180 ret = sprd_wdt_load_value(wdt, wdd->timeout, wdd->pretimeout);
181 if (ret)
182 return ret;
183
184 sprd_wdt_unlock(wdt->base);
185 val = readl_relaxed(wdt->base + SPRD_WDT_CTRL);
186 val |= SPRD_WDT_CNT_EN_BIT | SPRD_WDT_INT_EN_BIT | SPRD_WDT_RST_EN_BIT;
187 writel_relaxed(val, wdt->base + SPRD_WDT_CTRL);
188 sprd_wdt_lock(wdt->base);
189 set_bit(WDOG_HW_RUNNING, &wdd->status);
190
191 return 0;
192}
193
194static int sprd_wdt_stop(struct watchdog_device *wdd)
195{
196 struct sprd_wdt *wdt = to_sprd_wdt(wdd);
197 u32 val;
198
199 sprd_wdt_unlock(wdt->base);
200 val = readl_relaxed(wdt->base + SPRD_WDT_CTRL);
201 val &= ~(SPRD_WDT_CNT_EN_BIT | SPRD_WDT_RST_EN_BIT |
202 SPRD_WDT_INT_EN_BIT);
203 writel_relaxed(val, wdt->base + SPRD_WDT_CTRL);
204 sprd_wdt_lock(wdt->base);
205 return 0;
206}
207
208static int sprd_wdt_set_timeout(struct watchdog_device *wdd,
209 u32 timeout)
210{
211 struct sprd_wdt *wdt = to_sprd_wdt(wdd);
212
213 if (timeout == wdd->timeout)
214 return 0;
215
216 wdd->timeout = timeout;
217
218 return sprd_wdt_load_value(wdt, timeout, wdd->pretimeout);
219}
220
221static int sprd_wdt_set_pretimeout(struct watchdog_device *wdd,
222 u32 new_pretimeout)
223{
224 struct sprd_wdt *wdt = to_sprd_wdt(wdd);
225
226 if (new_pretimeout < wdd->min_timeout)
227 return -EINVAL;
228
229 wdd->pretimeout = new_pretimeout;
230
231 return sprd_wdt_load_value(wdt, wdd->timeout, new_pretimeout);
232}
233
234static u32 sprd_wdt_get_timeleft(struct watchdog_device *wdd)
235{
236 struct sprd_wdt *wdt = to_sprd_wdt(wdd);
237 u32 val;
238
239 val = sprd_wdt_get_cnt_value(wdt);
240 return val / SPRD_WDT_CNT_STEP;
241}
242
243static const struct watchdog_ops sprd_wdt_ops = {
244 .owner = THIS_MODULE,
245 .start = sprd_wdt_start,
246 .stop = sprd_wdt_stop,
247 .set_timeout = sprd_wdt_set_timeout,
248 .set_pretimeout = sprd_wdt_set_pretimeout,
249 .get_timeleft = sprd_wdt_get_timeleft,
250};
251
252static const struct watchdog_info sprd_wdt_info = {
253 .options = WDIOF_SETTIMEOUT |
254 WDIOF_PRETIMEOUT |
255 WDIOF_MAGICCLOSE |
256 WDIOF_KEEPALIVEPING,
257 .identity = "Spreadtrum Watchdog Timer",
258};
259
260static int sprd_wdt_probe(struct platform_device *pdev)
261{
262 struct device *dev = &pdev->dev;
263 struct sprd_wdt *wdt;
264 int ret;
265
266 wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
267 if (!wdt)
268 return -ENOMEM;
269
270 wdt->base = devm_platform_ioremap_resource(pdev, 0);
271 if (IS_ERR(wdt->base))
272 return PTR_ERR(wdt->base);
273
274 wdt->enable = devm_clk_get(dev, "enable");
275 if (IS_ERR(wdt->enable)) {
276 dev_err(dev, "can't get the enable clock\n");
277 return PTR_ERR(wdt->enable);
278 }
279
280 wdt->rtc_enable = devm_clk_get(dev, "rtc_enable");
281 if (IS_ERR(wdt->rtc_enable)) {
282 dev_err(dev, "can't get the rtc enable clock\n");
283 return PTR_ERR(wdt->rtc_enable);
284 }
285
286 wdt->irq = platform_get_irq(pdev, 0);
287 if (wdt->irq < 0)
288 return wdt->irq;
289
290 ret = devm_request_irq(dev, wdt->irq, sprd_wdt_isr, IRQF_NO_SUSPEND,
291 "sprd-wdt", (void *)wdt);
292 if (ret) {
293 dev_err(dev, "failed to register irq\n");
294 return ret;
295 }
296
297 wdt->wdd.info = &sprd_wdt_info;
298 wdt->wdd.ops = &sprd_wdt_ops;
299 wdt->wdd.parent = dev;
300 wdt->wdd.min_timeout = SPRD_WDT_MIN_TIMEOUT;
301 wdt->wdd.max_timeout = SPRD_WDT_MAX_TIMEOUT;
302 wdt->wdd.timeout = SPRD_WDT_MAX_TIMEOUT;
303
304 ret = sprd_wdt_enable(wdt);
305 if (ret) {
306 dev_err(dev, "failed to enable wdt\n");
307 return ret;
308 }
309 ret = devm_add_action_or_reset(dev, sprd_wdt_disable, wdt);
310 if (ret) {
311 dev_err(dev, "Failed to add wdt disable action\n");
312 return ret;
313 }
314
315 watchdog_set_nowayout(&wdt->wdd, WATCHDOG_NOWAYOUT);
316 watchdog_init_timeout(&wdt->wdd, 0, dev);
317
318 ret = devm_watchdog_register_device(dev, &wdt->wdd);
319 if (ret) {
320 sprd_wdt_disable(wdt);
321 return ret;
322 }
323 platform_set_drvdata(pdev, wdt);
324
325 return 0;
326}
327
328static int __maybe_unused sprd_wdt_pm_suspend(struct device *dev)
329{
330 struct sprd_wdt *wdt = dev_get_drvdata(dev);
331
332 if (watchdog_active(&wdt->wdd))
333 sprd_wdt_stop(&wdt->wdd);
334 sprd_wdt_disable(wdt);
335
336 return 0;
337}
338
339static int __maybe_unused sprd_wdt_pm_resume(struct device *dev)
340{
341 struct sprd_wdt *wdt = dev_get_drvdata(dev);
342 int ret;
343
344 ret = sprd_wdt_enable(wdt);
345 if (ret)
346 return ret;
347
348 if (watchdog_active(&wdt->wdd)) {
349 ret = sprd_wdt_start(&wdt->wdd);
350 if (ret) {
351 sprd_wdt_disable(wdt);
352 return ret;
353 }
354 }
355
356 return 0;
357}
358
359static const struct dev_pm_ops sprd_wdt_pm_ops = {
360 SET_SYSTEM_SLEEP_PM_OPS(sprd_wdt_pm_suspend,
361 sprd_wdt_pm_resume)
362};
363
364static const struct of_device_id sprd_wdt_match_table[] = {
365 { .compatible = "sprd,sp9860-wdt", },
366 {},
367};
368MODULE_DEVICE_TABLE(of, sprd_wdt_match_table);
369
370static struct platform_driver sprd_watchdog_driver = {
371 .probe = sprd_wdt_probe,
372 .driver = {
373 .name = "sprd-wdt",
374 .of_match_table = sprd_wdt_match_table,
375 .pm = &sprd_wdt_pm_ops,
376 },
377};
378module_platform_driver(sprd_watchdog_driver);
379
380MODULE_AUTHOR("Eric Long <eric.long@spreadtrum.com>");
381MODULE_DESCRIPTION("Spreadtrum Watchdog Timer Controller Driver");
382MODULE_LICENSE("GPL v2");