1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2014, The Linux Foundation. All rights reserved.
3 */
4 #include <linux/bits.h>
5 #include <linux/clk.h>
6 #include <linux/delay.h>
7 #include <linux/interrupt.h>
8 #include <linux/io.h>
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/of.h>
12 #include <linux/platform_device.h>
13 #include <linux/watchdog.h>
14
15 enum wdt_reg {
16 WDT_RST,
17 WDT_EN,
18 WDT_STS,
19 WDT_BARK_TIME,
20 WDT_BITE_TIME,
21 };
22
23 #define QCOM_WDT_ENABLE BIT(0)
24
25 static const u32 reg_offset_data_apcs_tmr[] = {
26 [WDT_RST] = 0x38,
27 [WDT_EN] = 0x40,
28 [WDT_STS] = 0x44,
29 [WDT_BARK_TIME] = 0x4C,
30 [WDT_BITE_TIME] = 0x5C,
31 };
32
33 static const u32 reg_offset_data_kpss[] = {
34 [WDT_RST] = 0x4,
35 [WDT_EN] = 0x8,
36 [WDT_STS] = 0xC,
37 [WDT_BARK_TIME] = 0x10,
38 [WDT_BITE_TIME] = 0x14,
39 };
40
41 struct qcom_wdt_match_data {
42 const u32 *offset;
43 bool pretimeout;
44 };
45
46 struct qcom_wdt {
47 struct watchdog_device wdd;
48 unsigned long rate;
49 void __iomem *base;
50 const u32 *layout;
51 };
52
wdt_addr(struct qcom_wdt * wdt,enum wdt_reg reg)53 static void __iomem *wdt_addr(struct qcom_wdt *wdt, enum wdt_reg reg)
54 {
55 return wdt->base + wdt->layout[reg];
56 }
57
58 static inline
to_qcom_wdt(struct watchdog_device * wdd)59 struct qcom_wdt *to_qcom_wdt(struct watchdog_device *wdd)
60 {
61 return container_of(wdd, struct qcom_wdt, wdd);
62 }
63
qcom_wdt_isr(int irq,void * arg)64 static irqreturn_t qcom_wdt_isr(int irq, void *arg)
65 {
66 struct watchdog_device *wdd = arg;
67
68 watchdog_notify_pretimeout(wdd);
69
70 return IRQ_HANDLED;
71 }
72
qcom_wdt_start(struct watchdog_device * wdd)73 static int qcom_wdt_start(struct watchdog_device *wdd)
74 {
75 struct qcom_wdt *wdt = to_qcom_wdt(wdd);
76 unsigned int bark = wdd->timeout - wdd->pretimeout;
77
78 writel(0, wdt_addr(wdt, WDT_EN));
79 writel(1, wdt_addr(wdt, WDT_RST));
80 writel(bark * wdt->rate, wdt_addr(wdt, WDT_BARK_TIME));
81 writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BITE_TIME));
82 writel(QCOM_WDT_ENABLE, wdt_addr(wdt, WDT_EN));
83 return 0;
84 }
85
qcom_wdt_stop(struct watchdog_device * wdd)86 static int qcom_wdt_stop(struct watchdog_device *wdd)
87 {
88 struct qcom_wdt *wdt = to_qcom_wdt(wdd);
89
90 writel(0, wdt_addr(wdt, WDT_EN));
91 return 0;
92 }
93
qcom_wdt_ping(struct watchdog_device * wdd)94 static int qcom_wdt_ping(struct watchdog_device *wdd)
95 {
96 struct qcom_wdt *wdt = to_qcom_wdt(wdd);
97
98 writel(1, wdt_addr(wdt, WDT_RST));
99 return 0;
100 }
101
qcom_wdt_set_timeout(struct watchdog_device * wdd,unsigned int timeout)102 static int qcom_wdt_set_timeout(struct watchdog_device *wdd,
103 unsigned int timeout)
104 {
105 wdd->timeout = timeout;
106 return qcom_wdt_start(wdd);
107 }
108
qcom_wdt_set_pretimeout(struct watchdog_device * wdd,unsigned int timeout)109 static int qcom_wdt_set_pretimeout(struct watchdog_device *wdd,
110 unsigned int timeout)
111 {
112 wdd->pretimeout = timeout;
113 return qcom_wdt_start(wdd);
114 }
115
qcom_wdt_restart(struct watchdog_device * wdd,unsigned long action,void * data)116 static int qcom_wdt_restart(struct watchdog_device *wdd, unsigned long action,
117 void *data)
118 {
119 struct qcom_wdt *wdt = to_qcom_wdt(wdd);
120 u32 timeout;
121
122 /*
123 * Trigger watchdog bite:
124 * Setup BITE_TIME to be 128ms, and enable WDT.
125 */
126 timeout = 128 * wdt->rate / 1000;
127
128 writel(0, wdt_addr(wdt, WDT_EN));
129 writel(1, wdt_addr(wdt, WDT_RST));
130 writel(timeout, wdt_addr(wdt, WDT_BARK_TIME));
131 writel(timeout, wdt_addr(wdt, WDT_BITE_TIME));
132 writel(QCOM_WDT_ENABLE, wdt_addr(wdt, WDT_EN));
133
134 /*
135 * Actually make sure the above sequence hits hardware before sleeping.
136 */
137 wmb();
138
139 mdelay(150);
140 return 0;
141 }
142
qcom_wdt_is_running(struct watchdog_device * wdd)143 static int qcom_wdt_is_running(struct watchdog_device *wdd)
144 {
145 struct qcom_wdt *wdt = to_qcom_wdt(wdd);
146
147 return (readl(wdt_addr(wdt, WDT_EN)) & QCOM_WDT_ENABLE);
148 }
149
150 static const struct watchdog_ops qcom_wdt_ops = {
151 .start = qcom_wdt_start,
152 .stop = qcom_wdt_stop,
153 .ping = qcom_wdt_ping,
154 .set_timeout = qcom_wdt_set_timeout,
155 .set_pretimeout = qcom_wdt_set_pretimeout,
156 .restart = qcom_wdt_restart,
157 .owner = THIS_MODULE,
158 };
159
160 static const struct watchdog_info qcom_wdt_info = {
161 .options = WDIOF_KEEPALIVEPING
162 | WDIOF_MAGICCLOSE
163 | WDIOF_SETTIMEOUT
164 | WDIOF_CARDRESET,
165 .identity = KBUILD_MODNAME,
166 };
167
168 static const struct watchdog_info qcom_wdt_pt_info = {
169 .options = WDIOF_KEEPALIVEPING
170 | WDIOF_MAGICCLOSE
171 | WDIOF_SETTIMEOUT
172 | WDIOF_PRETIMEOUT
173 | WDIOF_CARDRESET,
174 .identity = KBUILD_MODNAME,
175 };
176
177 static const struct qcom_wdt_match_data match_data_apcs_tmr = {
178 .offset = reg_offset_data_apcs_tmr,
179 .pretimeout = false,
180 };
181
182 static const struct qcom_wdt_match_data match_data_kpss = {
183 .offset = reg_offset_data_kpss,
184 .pretimeout = true,
185 };
186
qcom_wdt_probe(struct platform_device * pdev)187 static int qcom_wdt_probe(struct platform_device *pdev)
188 {
189 struct device *dev = &pdev->dev;
190 struct qcom_wdt *wdt;
191 struct resource *res;
192 struct device_node *np = dev->of_node;
193 const struct qcom_wdt_match_data *data;
194 u32 percpu_offset;
195 int irq, ret;
196 struct clk *clk;
197
198 data = of_device_get_match_data(dev);
199 if (!data) {
200 dev_err(dev, "Unsupported QCOM WDT module\n");
201 return -ENODEV;
202 }
203
204 wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
205 if (!wdt)
206 return -ENOMEM;
207
208 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
209 if (!res)
210 return -ENOMEM;
211
212 /* We use CPU0's DGT for the watchdog */
213 if (of_property_read_u32(np, "cpu-offset", &percpu_offset))
214 percpu_offset = 0;
215
216 res->start += percpu_offset;
217 res->end += percpu_offset;
218
219 wdt->base = devm_ioremap_resource(dev, res);
220 if (IS_ERR(wdt->base))
221 return PTR_ERR(wdt->base);
222
223 clk = devm_clk_get_enabled(dev, NULL);
224 if (IS_ERR(clk)) {
225 dev_err(dev, "failed to get input clock\n");
226 return PTR_ERR(clk);
227 }
228
229 /*
230 * We use the clock rate to calculate the max timeout, so ensure it's
231 * not zero to avoid a divide-by-zero exception.
232 *
233 * WATCHDOG_CORE assumes units of seconds, if the WDT is clocked such
234 * that it would bite before a second elapses it's usefulness is
235 * limited. Bail if this is the case.
236 */
237 wdt->rate = clk_get_rate(clk);
238 if (wdt->rate == 0 ||
239 wdt->rate > 0x10000000U) {
240 dev_err(dev, "invalid clock rate\n");
241 return -EINVAL;
242 }
243
244 /* check if there is pretimeout support */
245 irq = platform_get_irq_optional(pdev, 0);
246 if (data->pretimeout && irq > 0) {
247 ret = devm_request_irq(dev, irq, qcom_wdt_isr, 0,
248 "wdt_bark", &wdt->wdd);
249 if (ret)
250 return ret;
251
252 wdt->wdd.info = &qcom_wdt_pt_info;
253 wdt->wdd.pretimeout = 1;
254 } else {
255 if (irq == -EPROBE_DEFER)
256 return -EPROBE_DEFER;
257
258 wdt->wdd.info = &qcom_wdt_info;
259 }
260
261 wdt->wdd.ops = &qcom_wdt_ops;
262 wdt->wdd.min_timeout = 1;
263 wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
264 wdt->wdd.parent = dev;
265 wdt->layout = data->offset;
266
267 if (readl(wdt_addr(wdt, WDT_STS)) & 1)
268 wdt->wdd.bootstatus = WDIOF_CARDRESET;
269
270 /*
271 * If 'timeout-sec' unspecified in devicetree, assume a 30 second
272 * default, unless the max timeout is less than 30 seconds, then use
273 * the max instead.
274 */
275 wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U);
276 watchdog_init_timeout(&wdt->wdd, 0, dev);
277
278 /*
279 * If WDT is already running, call WDT start which
280 * will stop the WDT, set timeouts as bootloader
281 * might use different ones and set running bit
282 * to inform the WDT subsystem to ping the WDT
283 */
284 if (qcom_wdt_is_running(&wdt->wdd)) {
285 qcom_wdt_start(&wdt->wdd);
286 set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
287 }
288
289 ret = devm_watchdog_register_device(dev, &wdt->wdd);
290 if (ret)
291 return ret;
292
293 platform_set_drvdata(pdev, wdt);
294 return 0;
295 }
296
qcom_wdt_suspend(struct device * dev)297 static int __maybe_unused qcom_wdt_suspend(struct device *dev)
298 {
299 struct qcom_wdt *wdt = dev_get_drvdata(dev);
300
301 if (watchdog_active(&wdt->wdd))
302 qcom_wdt_stop(&wdt->wdd);
303
304 return 0;
305 }
306
qcom_wdt_resume(struct device * dev)307 static int __maybe_unused qcom_wdt_resume(struct device *dev)
308 {
309 struct qcom_wdt *wdt = dev_get_drvdata(dev);
310
311 if (watchdog_active(&wdt->wdd))
312 qcom_wdt_start(&wdt->wdd);
313
314 return 0;
315 }
316
317 static const struct dev_pm_ops qcom_wdt_pm_ops = {
318 SET_LATE_SYSTEM_SLEEP_PM_OPS(qcom_wdt_suspend, qcom_wdt_resume)
319 };
320
321 static const struct of_device_id qcom_wdt_of_table[] = {
322 { .compatible = "qcom,kpss-timer", .data = &match_data_apcs_tmr },
323 { .compatible = "qcom,scss-timer", .data = &match_data_apcs_tmr },
324 { .compatible = "qcom,kpss-wdt", .data = &match_data_kpss },
325 { },
326 };
327 MODULE_DEVICE_TABLE(of, qcom_wdt_of_table);
328
329 static struct platform_driver qcom_watchdog_driver = {
330 .probe = qcom_wdt_probe,
331 .driver = {
332 .name = KBUILD_MODNAME,
333 .of_match_table = qcom_wdt_of_table,
334 .pm = &qcom_wdt_pm_ops,
335 },
336 };
337 module_platform_driver(qcom_watchdog_driver);
338
339 MODULE_DESCRIPTION("QCOM KPSS Watchdog Driver");
340 MODULE_LICENSE("GPL v2");
341