1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Mediatek Watchdog Driver
4 *
5 * Copyright (C) 2014 Matthias Brugger
6 *
7 * Matthias Brugger <matthias.bgg@gmail.com>
8 *
9 * Based on sunxi_wdt.c
10 */
11
12 #include <linux/err.h>
13 #include <linux/init.h>
14 #include <linux/io.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/of.h>
19 #include <linux/platform_device.h>
20 #include <linux/types.h>
21 #include <linux/watchdog.h>
22 #include <linux/delay.h>
23
24 #define WDT_MAX_TIMEOUT 31
25 #define WDT_MIN_TIMEOUT 1
26 #define WDT_LENGTH_TIMEOUT(n) ((n) << 5)
27
28 #define WDT_LENGTH 0x04
29 #define WDT_LENGTH_KEY 0x8
30
31 #define WDT_RST 0x08
32 #define WDT_RST_RELOAD 0x1971
33
34 #define WDT_MODE 0x00
35 #define WDT_MODE_EN (1 << 0)
36 #define WDT_MODE_EXT_POL_LOW (0 << 1)
37 #define WDT_MODE_EXT_POL_HIGH (1 << 1)
38 #define WDT_MODE_EXRST_EN (1 << 2)
39 #define WDT_MODE_IRQ_EN (1 << 3)
40 #define WDT_MODE_AUTO_START (1 << 4)
41 #define WDT_MODE_DUAL_EN (1 << 6)
42 #define WDT_MODE_KEY 0x22000000
43
44 #define WDT_SWRST 0x14
45 #define WDT_SWRST_KEY 0x1209
46
47 #define DRV_NAME "mtk-wdt"
48 #define DRV_VERSION "1.0"
49
50 static bool nowayout = WATCHDOG_NOWAYOUT;
51 static unsigned int timeout;
52
53 struct mtk_wdt_dev {
54 struct watchdog_device wdt_dev;
55 void __iomem *wdt_base;
56 };
57
mtk_wdt_restart(struct watchdog_device * wdt_dev,unsigned long action,void * data)58 static int mtk_wdt_restart(struct watchdog_device *wdt_dev,
59 unsigned long action, void *data)
60 {
61 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
62 void __iomem *wdt_base;
63
64 wdt_base = mtk_wdt->wdt_base;
65
66 while (1) {
67 writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST);
68 mdelay(5);
69 }
70
71 return 0;
72 }
73
mtk_wdt_ping(struct watchdog_device * wdt_dev)74 static int mtk_wdt_ping(struct watchdog_device *wdt_dev)
75 {
76 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
77 void __iomem *wdt_base = mtk_wdt->wdt_base;
78
79 iowrite32(WDT_RST_RELOAD, wdt_base + WDT_RST);
80
81 return 0;
82 }
83
mtk_wdt_set_timeout(struct watchdog_device * wdt_dev,unsigned int timeout)84 static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
85 unsigned int timeout)
86 {
87 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
88 void __iomem *wdt_base = mtk_wdt->wdt_base;
89 u32 reg;
90
91 wdt_dev->timeout = timeout;
92
93 /*
94 * One bit is the value of 512 ticks
95 * The clock has 32 KHz
96 */
97 reg = WDT_LENGTH_TIMEOUT(timeout << 6) | WDT_LENGTH_KEY;
98 iowrite32(reg, wdt_base + WDT_LENGTH);
99
100 mtk_wdt_ping(wdt_dev);
101
102 return 0;
103 }
104
mtk_wdt_stop(struct watchdog_device * wdt_dev)105 static int mtk_wdt_stop(struct watchdog_device *wdt_dev)
106 {
107 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
108 void __iomem *wdt_base = mtk_wdt->wdt_base;
109 u32 reg;
110
111 reg = readl(wdt_base + WDT_MODE);
112 reg &= ~WDT_MODE_EN;
113 reg |= WDT_MODE_KEY;
114 iowrite32(reg, wdt_base + WDT_MODE);
115
116 return 0;
117 }
118
mtk_wdt_start(struct watchdog_device * wdt_dev)119 static int mtk_wdt_start(struct watchdog_device *wdt_dev)
120 {
121 u32 reg;
122 struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
123 void __iomem *wdt_base = mtk_wdt->wdt_base;
124 int ret;
125
126 ret = mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
127 if (ret < 0)
128 return ret;
129
130 reg = ioread32(wdt_base + WDT_MODE);
131 reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
132 reg |= (WDT_MODE_EN | WDT_MODE_KEY);
133 iowrite32(reg, wdt_base + WDT_MODE);
134
135 return 0;
136 }
137
138 static const struct watchdog_info mtk_wdt_info = {
139 .identity = DRV_NAME,
140 .options = WDIOF_SETTIMEOUT |
141 WDIOF_KEEPALIVEPING |
142 WDIOF_MAGICCLOSE,
143 };
144
145 static const struct watchdog_ops mtk_wdt_ops = {
146 .owner = THIS_MODULE,
147 .start = mtk_wdt_start,
148 .stop = mtk_wdt_stop,
149 .ping = mtk_wdt_ping,
150 .set_timeout = mtk_wdt_set_timeout,
151 .restart = mtk_wdt_restart,
152 };
153
mtk_wdt_probe(struct platform_device * pdev)154 static int mtk_wdt_probe(struct platform_device *pdev)
155 {
156 struct mtk_wdt_dev *mtk_wdt;
157 struct resource *res;
158 int err;
159
160 mtk_wdt = devm_kzalloc(&pdev->dev, sizeof(*mtk_wdt), GFP_KERNEL);
161 if (!mtk_wdt)
162 return -ENOMEM;
163
164 platform_set_drvdata(pdev, mtk_wdt);
165
166 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
167 mtk_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
168 if (IS_ERR(mtk_wdt->wdt_base))
169 return PTR_ERR(mtk_wdt->wdt_base);
170
171 mtk_wdt->wdt_dev.info = &mtk_wdt_info;
172 mtk_wdt->wdt_dev.ops = &mtk_wdt_ops;
173 mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
174 mtk_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
175 mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
176 mtk_wdt->wdt_dev.parent = &pdev->dev;
177
178 watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, &pdev->dev);
179 watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout);
180 watchdog_set_restart_priority(&mtk_wdt->wdt_dev, 128);
181
182 watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);
183
184 mtk_wdt_stop(&mtk_wdt->wdt_dev);
185
186 err = watchdog_register_device(&mtk_wdt->wdt_dev);
187 if (unlikely(err))
188 return err;
189
190 dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n",
191 mtk_wdt->wdt_dev.timeout, nowayout);
192
193 return 0;
194 }
195
mtk_wdt_shutdown(struct platform_device * pdev)196 static void mtk_wdt_shutdown(struct platform_device *pdev)
197 {
198 struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev);
199
200 if (watchdog_active(&mtk_wdt->wdt_dev))
201 mtk_wdt_stop(&mtk_wdt->wdt_dev);
202 }
203
mtk_wdt_remove(struct platform_device * pdev)204 static int mtk_wdt_remove(struct platform_device *pdev)
205 {
206 struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev);
207
208 watchdog_unregister_device(&mtk_wdt->wdt_dev);
209
210 return 0;
211 }
212
213 #ifdef CONFIG_PM_SLEEP
mtk_wdt_suspend(struct device * dev)214 static int mtk_wdt_suspend(struct device *dev)
215 {
216 struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev);
217
218 if (watchdog_active(&mtk_wdt->wdt_dev))
219 mtk_wdt_stop(&mtk_wdt->wdt_dev);
220
221 return 0;
222 }
223
mtk_wdt_resume(struct device * dev)224 static int mtk_wdt_resume(struct device *dev)
225 {
226 struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev);
227
228 if (watchdog_active(&mtk_wdt->wdt_dev)) {
229 mtk_wdt_start(&mtk_wdt->wdt_dev);
230 mtk_wdt_ping(&mtk_wdt->wdt_dev);
231 }
232
233 return 0;
234 }
235 #endif
236
237 static const struct of_device_id mtk_wdt_dt_ids[] = {
238 { .compatible = "mediatek,mt6589-wdt" },
239 { /* sentinel */ }
240 };
241 MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids);
242
243 static const struct dev_pm_ops mtk_wdt_pm_ops = {
244 SET_SYSTEM_SLEEP_PM_OPS(mtk_wdt_suspend,
245 mtk_wdt_resume)
246 };
247
248 static struct platform_driver mtk_wdt_driver = {
249 .probe = mtk_wdt_probe,
250 .remove = mtk_wdt_remove,
251 .shutdown = mtk_wdt_shutdown,
252 .driver = {
253 .name = DRV_NAME,
254 .pm = &mtk_wdt_pm_ops,
255 .of_match_table = mtk_wdt_dt_ids,
256 },
257 };
258
259 module_platform_driver(mtk_wdt_driver);
260
261 module_param(timeout, uint, 0);
262 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
263
264 module_param(nowayout, bool, 0);
265 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
266 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
267
268 MODULE_LICENSE("GPL");
269 MODULE_AUTHOR("Matthias Brugger <matthias.bgg@gmail.com>");
270 MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver");
271 MODULE_VERSION(DRV_VERSION);
272
