1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Watchdog driver for Intel Keem Bay non-secure watchdog.
4 *
5 * Copyright (C) 2020 Intel Corporation
6 */
7
8 #include <linux/arm-smccc.h>
9 #include <linux/bits.h>
10 #include <linux/clk.h>
11 #include <linux/interrupt.h>
12 #include <linux/io.h>
13 #include <linux/limits.h>
14 #include <linux/module.h>
15 #include <linux/mod_devicetable.h>
16 #include <linux/platform_device.h>
17 #include <linux/reboot.h>
18 #include <linux/watchdog.h>
19
20 /* Non-secure watchdog register offsets */
21 #define TIM_WATCHDOG 0x0
22 #define TIM_WATCHDOG_INT_THRES 0x4
23 #define TIM_WDOG_EN 0x8
24 #define TIM_SAFE 0xc
25
26 #define WDT_TH_INT_MASK BIT(8)
27 #define WDT_TO_INT_MASK BIT(9)
28 #define WDT_INT_CLEAR_SMC 0x8200ff18
29
30 #define WDT_UNLOCK 0xf1d0dead
31 #define WDT_DISABLE 0x0
32 #define WDT_ENABLE 0x1
33
34 #define WDT_LOAD_MAX U32_MAX
35 #define WDT_LOAD_MIN 1
36
37 #define WDT_TIMEOUT 5
38 #define WDT_PRETIMEOUT 4
39
40 static unsigned int timeout = WDT_TIMEOUT;
41 module_param(timeout, int, 0);
42 MODULE_PARM_DESC(timeout, "Watchdog timeout period in seconds (default = "
43 __MODULE_STRING(WDT_TIMEOUT) ")");
44
45 static bool nowayout = WATCHDOG_NOWAYOUT;
46 module_param(nowayout, bool, 0);
47 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = "
48 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
49
50 struct keembay_wdt {
51 struct watchdog_device wdd;
52 struct clk *clk;
53 unsigned int rate;
54 int to_irq;
55 int th_irq;
56 void __iomem *base;
57 };
58
keembay_wdt_readl(struct keembay_wdt * wdt,u32 offset)59 static inline u32 keembay_wdt_readl(struct keembay_wdt *wdt, u32 offset)
60 {
61 return readl(wdt->base + offset);
62 }
63
keembay_wdt_writel(struct keembay_wdt * wdt,u32 offset,u32 val)64 static inline void keembay_wdt_writel(struct keembay_wdt *wdt, u32 offset, u32 val)
65 {
66 writel(WDT_UNLOCK, wdt->base + TIM_SAFE);
67 writel(val, wdt->base + offset);
68 }
69
keembay_wdt_set_timeout_reg(struct watchdog_device * wdog)70 static void keembay_wdt_set_timeout_reg(struct watchdog_device *wdog)
71 {
72 struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
73
74 keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout * wdt->rate);
75 }
76
keembay_wdt_set_pretimeout_reg(struct watchdog_device * wdog)77 static void keembay_wdt_set_pretimeout_reg(struct watchdog_device *wdog)
78 {
79 struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
80 u32 th_val = 0;
81
82 if (wdog->pretimeout)
83 th_val = wdog->timeout - wdog->pretimeout;
84
85 keembay_wdt_writel(wdt, TIM_WATCHDOG_INT_THRES, th_val * wdt->rate);
86 }
87
keembay_wdt_start(struct watchdog_device * wdog)88 static int keembay_wdt_start(struct watchdog_device *wdog)
89 {
90 struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
91
92 keembay_wdt_writel(wdt, TIM_WDOG_EN, WDT_ENABLE);
93
94 return 0;
95 }
96
keembay_wdt_stop(struct watchdog_device * wdog)97 static int keembay_wdt_stop(struct watchdog_device *wdog)
98 {
99 struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
100
101 keembay_wdt_writel(wdt, TIM_WDOG_EN, WDT_DISABLE);
102
103 return 0;
104 }
105
keembay_wdt_ping(struct watchdog_device * wdog)106 static int keembay_wdt_ping(struct watchdog_device *wdog)
107 {
108 keembay_wdt_set_timeout_reg(wdog);
109
110 return 0;
111 }
112
keembay_wdt_set_timeout(struct watchdog_device * wdog,u32 t)113 static int keembay_wdt_set_timeout(struct watchdog_device *wdog, u32 t)
114 {
115 wdog->timeout = t;
116 keembay_wdt_set_timeout_reg(wdog);
117 keembay_wdt_set_pretimeout_reg(wdog);
118
119 return 0;
120 }
121
keembay_wdt_set_pretimeout(struct watchdog_device * wdog,u32 t)122 static int keembay_wdt_set_pretimeout(struct watchdog_device *wdog, u32 t)
123 {
124 if (t > wdog->timeout)
125 return -EINVAL;
126
127 wdog->pretimeout = t;
128 keembay_wdt_set_pretimeout_reg(wdog);
129
130 return 0;
131 }
132
keembay_wdt_get_timeleft(struct watchdog_device * wdog)133 static unsigned int keembay_wdt_get_timeleft(struct watchdog_device *wdog)
134 {
135 struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
136
137 return keembay_wdt_readl(wdt, TIM_WATCHDOG) / wdt->rate;
138 }
139
140 /*
141 * SMC call is used to clear the interrupt bits, because the TIM_GEN_CONFIG
142 * register is in the secure bank.
143 */
keembay_wdt_to_isr(int irq,void * dev_id)144 static irqreturn_t keembay_wdt_to_isr(int irq, void *dev_id)
145 {
146 struct keembay_wdt *wdt = dev_id;
147 struct arm_smccc_res res;
148
149 arm_smccc_smc(WDT_INT_CLEAR_SMC, WDT_TO_INT_MASK, 0, 0, 0, 0, 0, 0, &res);
150 dev_crit(wdt->wdd.parent, "Intel Keem Bay non-secure wdt timeout.\n");
151 emergency_restart();
152
153 return IRQ_HANDLED;
154 }
155
keembay_wdt_th_isr(int irq,void * dev_id)156 static irqreturn_t keembay_wdt_th_isr(int irq, void *dev_id)
157 {
158 struct keembay_wdt *wdt = dev_id;
159 struct arm_smccc_res res;
160
161 keembay_wdt_set_pretimeout(&wdt->wdd, 0x0);
162
163 arm_smccc_smc(WDT_INT_CLEAR_SMC, WDT_TH_INT_MASK, 0, 0, 0, 0, 0, 0, &res);
164 dev_crit(wdt->wdd.parent, "Intel Keem Bay non-secure wdt pre-timeout.\n");
165 watchdog_notify_pretimeout(&wdt->wdd);
166
167 return IRQ_HANDLED;
168 }
169
170 static const struct watchdog_info keembay_wdt_info = {
171 .identity = "Intel Keem Bay Watchdog Timer",
172 .options = WDIOF_SETTIMEOUT |
173 WDIOF_PRETIMEOUT |
174 WDIOF_MAGICCLOSE |
175 WDIOF_KEEPALIVEPING,
176 };
177
178 static const struct watchdog_ops keembay_wdt_ops = {
179 .owner = THIS_MODULE,
180 .start = keembay_wdt_start,
181 .stop = keembay_wdt_stop,
182 .ping = keembay_wdt_ping,
183 .set_timeout = keembay_wdt_set_timeout,
184 .set_pretimeout = keembay_wdt_set_pretimeout,
185 .get_timeleft = keembay_wdt_get_timeleft,
186 };
187
keembay_wdt_probe(struct platform_device * pdev)188 static int keembay_wdt_probe(struct platform_device *pdev)
189 {
190 struct device *dev = &pdev->dev;
191 struct keembay_wdt *wdt;
192 int ret;
193
194 wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
195 if (!wdt)
196 return -ENOMEM;
197
198 wdt->base = devm_platform_ioremap_resource(pdev, 0);
199 if (IS_ERR(wdt->base))
200 return PTR_ERR(wdt->base);
201
202 /* we do not need to enable the clock as it is enabled by default */
203 wdt->clk = devm_clk_get(dev, NULL);
204 if (IS_ERR(wdt->clk))
205 return dev_err_probe(dev, PTR_ERR(wdt->clk), "Failed to get clock\n");
206
207 wdt->rate = clk_get_rate(wdt->clk);
208 if (!wdt->rate)
209 return dev_err_probe(dev, -EINVAL, "Failed to get clock rate\n");
210
211 wdt->th_irq = platform_get_irq_byname(pdev, "threshold");
212 if (wdt->th_irq < 0)
213 return dev_err_probe(dev, wdt->th_irq, "Failed to get IRQ for threshold\n");
214
215 ret = devm_request_irq(dev, wdt->th_irq, keembay_wdt_th_isr, 0,
216 "keembay-wdt", wdt);
217 if (ret)
218 return dev_err_probe(dev, ret, "Failed to request IRQ for threshold\n");
219
220 wdt->to_irq = platform_get_irq_byname(pdev, "timeout");
221 if (wdt->to_irq < 0)
222 return dev_err_probe(dev, wdt->to_irq, "Failed to get IRQ for timeout\n");
223
224 ret = devm_request_irq(dev, wdt->to_irq, keembay_wdt_to_isr, 0,
225 "keembay-wdt", wdt);
226 if (ret)
227 return dev_err_probe(dev, ret, "Failed to request IRQ for timeout\n");
228
229 wdt->wdd.parent = dev;
230 wdt->wdd.info = &keembay_wdt_info;
231 wdt->wdd.ops = &keembay_wdt_ops;
232 wdt->wdd.min_timeout = WDT_LOAD_MIN;
233 wdt->wdd.max_timeout = WDT_LOAD_MAX / wdt->rate;
234 wdt->wdd.timeout = WDT_TIMEOUT;
235 wdt->wdd.pretimeout = WDT_PRETIMEOUT;
236
237 watchdog_set_drvdata(&wdt->wdd, wdt);
238 watchdog_set_nowayout(&wdt->wdd, nowayout);
239 watchdog_init_timeout(&wdt->wdd, timeout, dev);
240 keembay_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout);
241 keembay_wdt_set_pretimeout(&wdt->wdd, wdt->wdd.pretimeout);
242
243 ret = devm_watchdog_register_device(dev, &wdt->wdd);
244 if (ret)
245 return dev_err_probe(dev, ret, "Failed to register watchdog device.\n");
246
247 platform_set_drvdata(pdev, wdt);
248 dev_info(dev, "Initial timeout %d sec%s.\n",
249 wdt->wdd.timeout, nowayout ? ", nowayout" : "");
250
251 return 0;
252 }
253
keembay_wdt_suspend(struct device * dev)254 static int __maybe_unused keembay_wdt_suspend(struct device *dev)
255 {
256 struct keembay_wdt *wdt = dev_get_drvdata(dev);
257
258 if (watchdog_active(&wdt->wdd))
259 return keembay_wdt_stop(&wdt->wdd);
260
261 return 0;
262 }
263
keembay_wdt_resume(struct device * dev)264 static int __maybe_unused keembay_wdt_resume(struct device *dev)
265 {
266 struct keembay_wdt *wdt = dev_get_drvdata(dev);
267
268 if (watchdog_active(&wdt->wdd))
269 return keembay_wdt_start(&wdt->wdd);
270
271 return 0;
272 }
273
274 static SIMPLE_DEV_PM_OPS(keembay_wdt_pm_ops, keembay_wdt_suspend,
275 keembay_wdt_resume);
276
277 static const struct of_device_id keembay_wdt_match[] = {
278 { .compatible = "intel,keembay-wdt" },
279 { }
280 };
281 MODULE_DEVICE_TABLE(of, keembay_wdt_match);
282
283 static struct platform_driver keembay_wdt_driver = {
284 .probe = keembay_wdt_probe,
285 .driver = {
286 .name = "keembay_wdt",
287 .of_match_table = keembay_wdt_match,
288 .pm = &keembay_wdt_pm_ops,
289 },
290 };
291
292 module_platform_driver(keembay_wdt_driver);
293
294 MODULE_DESCRIPTION("Intel Keem Bay SoC watchdog driver");
295 MODULE_AUTHOR("Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com");
296 MODULE_LICENSE("GPL v2");
297