blob: 1f4155ee3404de97e4eee3988dc7823c9874ecbd [file] [log] [blame]
Carlo Caione22e1b8f2014-09-20 19:06:50 +02001/*
2 * Meson Watchdog Driver
3 *
4 * Copyright (c) 2014 Carlo Caione
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/clk.h>
13#include <linux/delay.h>
14#include <linux/err.h>
15#include <linux/init.h>
16#include <linux/io.h>
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/moduleparam.h>
20#include <linux/notifier.h>
21#include <linux/of.h>
22#include <linux/platform_device.h>
23#include <linux/reboot.h>
24#include <linux/types.h>
25#include <linux/watchdog.h>
26
27#define DRV_NAME "meson_wdt"
28
29#define MESON_WDT_TC 0x00
30#define MESON_WDT_TC_EN BIT(22)
31#define MESON_WDT_TC_TM_MASK 0x3fffff
32#define MESON_WDT_DC_RESET (3 << 24)
33
34#define MESON_WDT_RESET 0x04
35
36#define MESON_WDT_TIMEOUT 30
37#define MESON_WDT_MIN_TIMEOUT 1
38#define MESON_WDT_MAX_TIMEOUT (MESON_WDT_TC_TM_MASK / 100000)
39
40#define MESON_SEC_TO_TC(s) ((s) * 100000)
41
42static bool nowayout = WATCHDOG_NOWAYOUT;
43static unsigned int timeout = MESON_WDT_TIMEOUT;
44
45struct meson_wdt_dev {
46 struct watchdog_device wdt_dev;
47 void __iomem *wdt_base;
48 struct notifier_block restart_handler;
49};
50
51static int meson_restart_handle(struct notifier_block *this, unsigned long mode,
52 void *cmd)
53{
Carlo Caione06980b22014-10-09 21:59:16 +020054 u32 tc_reboot = MESON_WDT_DC_RESET | MESON_WDT_TC_EN;
Carlo Caione22e1b8f2014-09-20 19:06:50 +020055 struct meson_wdt_dev *meson_wdt = container_of(this,
56 struct meson_wdt_dev,
57 restart_handler);
58
59 while (1) {
60 writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC);
61 mdelay(5);
62 }
63
64 return NOTIFY_DONE;
65}
66
67static int meson_wdt_ping(struct watchdog_device *wdt_dev)
68{
69 struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
70
71 writel(0, meson_wdt->wdt_base + MESON_WDT_RESET);
72
73 return 0;
74}
75
76static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev,
77 unsigned int timeout)
78{
79 struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
80 u32 reg;
81
82 reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
83 reg &= ~MESON_WDT_TC_TM_MASK;
84 reg |= MESON_SEC_TO_TC(timeout);
85 writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
86}
87
88static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev,
89 unsigned int timeout)
90{
91 wdt_dev->timeout = timeout;
92
93 meson_wdt_change_timeout(wdt_dev, timeout);
94 meson_wdt_ping(wdt_dev);
95
96 return 0;
97}
98
99static int meson_wdt_stop(struct watchdog_device *wdt_dev)
100{
101 struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
102 u32 reg;
103
104 reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
105 reg &= ~MESON_WDT_TC_EN;
106 writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
107
108 return 0;
109}
110
111static int meson_wdt_start(struct watchdog_device *wdt_dev)
112{
113 struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
114 u32 reg;
115
116 meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout);
117 meson_wdt_ping(wdt_dev);
118
119 reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
120 reg |= MESON_WDT_TC_EN;
121 writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
122
123 return 0;
124}
125
126static const struct watchdog_info meson_wdt_info = {
127 .identity = DRV_NAME,
128 .options = WDIOF_SETTIMEOUT |
129 WDIOF_KEEPALIVEPING |
130 WDIOF_MAGICCLOSE,
131};
132
133static const struct watchdog_ops meson_wdt_ops = {
134 .owner = THIS_MODULE,
135 .start = meson_wdt_start,
136 .stop = meson_wdt_stop,
137 .ping = meson_wdt_ping,
138 .set_timeout = meson_wdt_set_timeout,
139};
140
141static int meson_wdt_probe(struct platform_device *pdev)
142{
143 struct resource *res;
144 struct meson_wdt_dev *meson_wdt;
145 int err;
146
147 meson_wdt = devm_kzalloc(&pdev->dev, sizeof(*meson_wdt), GFP_KERNEL);
148 if (!meson_wdt)
149 return -ENOMEM;
150
151 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
152 meson_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
153 if (IS_ERR(meson_wdt->wdt_base))
154 return PTR_ERR(meson_wdt->wdt_base);
155
156 meson_wdt->wdt_dev.parent = &pdev->dev;
157 meson_wdt->wdt_dev.info = &meson_wdt_info;
158 meson_wdt->wdt_dev.ops = &meson_wdt_ops;
159 meson_wdt->wdt_dev.timeout = MESON_WDT_TIMEOUT;
160 meson_wdt->wdt_dev.max_timeout = MESON_WDT_MAX_TIMEOUT;
161 meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT;
162
163 watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt);
164
165 watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, &pdev->dev);
166 watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout);
167
168 meson_wdt_stop(&meson_wdt->wdt_dev);
169
170 err = watchdog_register_device(&meson_wdt->wdt_dev);
171 if (err)
172 return err;
173
174 platform_set_drvdata(pdev, meson_wdt);
175
176 meson_wdt->restart_handler.notifier_call = meson_restart_handle;
177 meson_wdt->restart_handler.priority = 128;
178 err = register_restart_handler(&meson_wdt->restart_handler);
179 if (err)
180 dev_err(&pdev->dev,
181 "cannot register restart handler (err=%d)\n", err);
182
183 dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
184 meson_wdt->wdt_dev.timeout, nowayout);
185
186 return 0;
187}
188
189static int meson_wdt_remove(struct platform_device *pdev)
190{
191 struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev);
192
193 unregister_restart_handler(&meson_wdt->restart_handler);
194
195 watchdog_unregister_device(&meson_wdt->wdt_dev);
196
197 return 0;
198}
199
200static void meson_wdt_shutdown(struct platform_device *pdev)
201{
202 struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev);
203
204 meson_wdt_stop(&meson_wdt->wdt_dev);
205}
206
207static const struct of_device_id meson_wdt_dt_ids[] = {
208 { .compatible = "amlogic,meson6-wdt" },
209 { /* sentinel */ }
210};
211MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids);
212
213static struct platform_driver meson_wdt_driver = {
214 .probe = meson_wdt_probe,
215 .remove = meson_wdt_remove,
216 .shutdown = meson_wdt_shutdown,
217 .driver = {
Carlo Caione22e1b8f2014-09-20 19:06:50 +0200218 .name = DRV_NAME,
219 .of_match_table = meson_wdt_dt_ids,
220 },
221};
222
223module_platform_driver(meson_wdt_driver);
224
225module_param(timeout, uint, 0);
226MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
227
228module_param(nowayout, bool, 0);
229MODULE_PARM_DESC(nowayout,
230 "Watchdog cannot be stopped once started (default="
231 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
232
233MODULE_LICENSE("GPL");
234MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
235MODULE_DESCRIPTION("Meson Watchdog Timer Driver");