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1 | /* |
2 | * Mediatek Watchdog Driver | |
3 | * | |
4 | * Copyright (C) 2014 Matthias Brugger | |
5 | * | |
6 | * Matthias Brugger <matthias.bgg@gmail.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2 of the License, or | |
11 | * (at your option) any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * Based on sunxi_wdt.c | |
19 | */ | |
20 | ||
21 | #include <linux/err.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/io.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/module.h> | |
26 | #include <linux/moduleparam.h> | |
27 | #include <linux/of.h> | |
28 | #include <linux/platform_device.h> | |
29 | #include <linux/types.h> | |
30 | #include <linux/watchdog.h> | |
31 | #include <linux/notifier.h> | |
32 | #include <linux/reboot.h> | |
33 | #include <linux/delay.h> | |
34 | ||
35 | #define WDT_MAX_TIMEOUT 31 | |
36 | #define WDT_MIN_TIMEOUT 1 | |
37 | #define WDT_LENGTH_TIMEOUT(n) ((n) << 5) | |
38 | ||
39 | #define WDT_LENGTH 0x04 | |
40 | #define WDT_LENGTH_KEY 0x8 | |
41 | ||
42 | #define WDT_RST 0x08 | |
43 | #define WDT_RST_RELOAD 0x1971 | |
44 | ||
45 | #define WDT_MODE 0x00 | |
46 | #define WDT_MODE_EN (1 << 0) | |
47 | #define WDT_MODE_EXT_POL_LOW (0 << 1) | |
48 | #define WDT_MODE_EXT_POL_HIGH (1 << 1) | |
49 | #define WDT_MODE_EXRST_EN (1 << 2) | |
50 | #define WDT_MODE_IRQ_EN (1 << 3) | |
51 | #define WDT_MODE_AUTO_START (1 << 4) | |
52 | #define WDT_MODE_DUAL_EN (1 << 6) | |
53 | #define WDT_MODE_KEY 0x22000000 | |
54 | ||
55 | #define WDT_SWRST 0x14 | |
56 | #define WDT_SWRST_KEY 0x1209 | |
57 | ||
58 | #define DRV_NAME "mtk-wdt" | |
59 | #define DRV_VERSION "1.0" | |
60 | ||
61 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
62 | static unsigned int timeout = WDT_MAX_TIMEOUT; | |
63 | ||
64 | struct mtk_wdt_dev { | |
65 | struct watchdog_device wdt_dev; | |
66 | void __iomem *wdt_base; | |
67 | struct notifier_block restart_handler; | |
68 | }; | |
69 | ||
70 | static int mtk_reset_handler(struct notifier_block *this, unsigned long mode, | |
71 | void *cmd) | |
72 | { | |
73 | struct mtk_wdt_dev *mtk_wdt; | |
74 | void __iomem *wdt_base; | |
75 | ||
76 | mtk_wdt = container_of(this, struct mtk_wdt_dev, restart_handler); | |
77 | wdt_base = mtk_wdt->wdt_base; | |
78 | ||
79 | while (1) { | |
80 | writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST); | |
81 | mdelay(5); | |
82 | } | |
83 | ||
84 | return NOTIFY_DONE; | |
85 | } | |
86 | ||
87 | static int mtk_wdt_ping(struct watchdog_device *wdt_dev) | |
88 | { | |
89 | struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); | |
90 | void __iomem *wdt_base = mtk_wdt->wdt_base; | |
91 | ||
92 | iowrite32(WDT_RST_RELOAD, wdt_base + WDT_RST); | |
93 | ||
94 | return 0; | |
95 | } | |
96 | ||
97 | static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev, | |
98 | unsigned int timeout) | |
99 | { | |
100 | struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); | |
101 | void __iomem *wdt_base = mtk_wdt->wdt_base; | |
102 | u32 reg; | |
103 | ||
104 | wdt_dev->timeout = timeout; | |
105 | ||
106 | /* | |
107 | * One bit is the value of 512 ticks | |
108 | * The clock has 32 KHz | |
109 | */ | |
110 | reg = WDT_LENGTH_TIMEOUT(timeout << 6) | WDT_LENGTH_KEY; | |
111 | iowrite32(reg, wdt_base + WDT_LENGTH); | |
112 | ||
113 | mtk_wdt_ping(wdt_dev); | |
114 | ||
115 | return 0; | |
116 | } | |
117 | ||
118 | static int mtk_wdt_stop(struct watchdog_device *wdt_dev) | |
119 | { | |
120 | struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); | |
121 | void __iomem *wdt_base = mtk_wdt->wdt_base; | |
122 | u32 reg; | |
123 | ||
124 | reg = readl(wdt_base + WDT_MODE); | |
125 | reg &= ~WDT_MODE_EN; | |
126 | iowrite32(reg, wdt_base + WDT_MODE); | |
127 | ||
128 | return 0; | |
129 | } | |
130 | ||
131 | static int mtk_wdt_start(struct watchdog_device *wdt_dev) | |
132 | { | |
133 | u32 reg; | |
134 | struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); | |
135 | void __iomem *wdt_base = mtk_wdt->wdt_base; | |
136 | u32 ret; | |
137 | ||
138 | ret = mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout); | |
139 | if (ret < 0) | |
140 | return ret; | |
141 | ||
142 | reg = ioread32(wdt_base + WDT_MODE); | |
143 | reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN); | |
144 | reg |= (WDT_MODE_EN | WDT_MODE_KEY); | |
145 | iowrite32(reg, wdt_base + WDT_MODE); | |
146 | ||
147 | return 0; | |
148 | } | |
149 | ||
150 | static const struct watchdog_info mtk_wdt_info = { | |
151 | .identity = DRV_NAME, | |
152 | .options = WDIOF_SETTIMEOUT | | |
153 | WDIOF_KEEPALIVEPING | | |
154 | WDIOF_MAGICCLOSE, | |
155 | }; | |
156 | ||
157 | static const struct watchdog_ops mtk_wdt_ops = { | |
158 | .owner = THIS_MODULE, | |
159 | .start = mtk_wdt_start, | |
160 | .stop = mtk_wdt_stop, | |
161 | .ping = mtk_wdt_ping, | |
162 | .set_timeout = mtk_wdt_set_timeout, | |
163 | }; | |
164 | ||
165 | static int mtk_wdt_probe(struct platform_device *pdev) | |
166 | { | |
167 | struct mtk_wdt_dev *mtk_wdt; | |
168 | struct resource *res; | |
169 | int err; | |
170 | ||
171 | mtk_wdt = devm_kzalloc(&pdev->dev, sizeof(*mtk_wdt), GFP_KERNEL); | |
172 | if (!mtk_wdt) | |
173 | return -ENOMEM; | |
174 | ||
175 | platform_set_drvdata(pdev, mtk_wdt); | |
176 | ||
177 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
178 | mtk_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res); | |
179 | if (IS_ERR(mtk_wdt->wdt_base)) | |
180 | return PTR_ERR(mtk_wdt->wdt_base); | |
181 | ||
182 | mtk_wdt->wdt_dev.info = &mtk_wdt_info; | |
183 | mtk_wdt->wdt_dev.ops = &mtk_wdt_ops; | |
184 | mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT; | |
185 | mtk_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT; | |
186 | mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT; | |
187 | mtk_wdt->wdt_dev.parent = &pdev->dev; | |
188 | ||
189 | watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, &pdev->dev); | |
190 | watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout); | |
191 | ||
192 | watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt); | |
193 | ||
194 | mtk_wdt_stop(&mtk_wdt->wdt_dev); | |
195 | ||
196 | err = watchdog_register_device(&mtk_wdt->wdt_dev); | |
197 | if (unlikely(err)) | |
198 | return err; | |
199 | ||
200 | mtk_wdt->restart_handler.notifier_call = mtk_reset_handler; | |
201 | mtk_wdt->restart_handler.priority = 128; | |
202 | err = register_restart_handler(&mtk_wdt->restart_handler); | |
203 | if (err) | |
204 | dev_warn(&pdev->dev, | |
205 | "cannot register restart handler (err=%d)\n", err); | |
206 | ||
207 | dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n", | |
208 | mtk_wdt->wdt_dev.timeout, nowayout); | |
209 | ||
210 | return 0; | |
211 | } | |
212 | ||
213 | static int mtk_wdt_remove(struct platform_device *pdev) | |
214 | { | |
215 | struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev); | |
216 | ||
217 | unregister_restart_handler(&mtk_wdt->restart_handler); | |
218 | ||
219 | watchdog_unregister_device(&mtk_wdt->wdt_dev); | |
220 | ||
221 | return 0; | |
222 | } | |
223 | ||
224 | static const struct of_device_id mtk_wdt_dt_ids[] = { | |
225 | { .compatible = "mediatek,mt6589-wdt" }, | |
226 | { /* sentinel */ } | |
227 | }; | |
228 | MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids); | |
229 | ||
230 | static struct platform_driver mtk_wdt_driver = { | |
231 | .probe = mtk_wdt_probe, | |
232 | .remove = mtk_wdt_remove, | |
233 | .driver = { | |
234 | .name = DRV_NAME, | |
235 | .of_match_table = mtk_wdt_dt_ids, | |
236 | }, | |
237 | }; | |
238 | ||
239 | module_platform_driver(mtk_wdt_driver); | |
240 | ||
241 | module_param(timeout, uint, 0); | |
242 | MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); | |
243 | ||
244 | module_param(nowayout, bool, 0); | |
245 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" | |
246 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
247 | ||
248 | MODULE_LICENSE("GPL"); | |
249 | MODULE_AUTHOR("Matthias Brugger <matthias.bgg@gmail.com>"); | |
250 | MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver"); | |
251 | MODULE_VERSION(DRV_VERSION); |