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