blob: a6a2cebb25879242b8408b1537838a67d932b2b3 [file] [log] [blame]
Lubomir Rintel938d0a82013-06-18 19:44:48 +02001/*
2 * Watchdog driver for Broadcom BCM2835
3 *
4 * "bcm2708_wdog" driver written by Luke Diamand that was obtained from
5 * branch "rpi-3.6.y" of git://github.com/raspberrypi/linux.git was used
6 * as a hardware reference for the Broadcom BCM2835 watchdog timer.
7 *
8 * Copyright (C) 2013 Lubomir Rintel <lkundrak@v3.sk>
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the
12 * Free Software Foundation; either version 2 of the License, or (at your
13 * option) any later version.
14 */
15
16#include <linux/types.h>
17#include <linux/module.h>
18#include <linux/io.h>
19#include <linux/watchdog.h>
20#include <linux/platform_device.h>
21#include <linux/of_address.h>
22#include <linux/miscdevice.h>
23
24#define PM_RSTC 0x1c
25#define PM_WDOG 0x24
26
27#define PM_PASSWORD 0x5a000000
28
29#define PM_WDOG_TIME_SET 0x000fffff
30#define PM_RSTC_WRCFG_CLR 0xffffffcf
31#define PM_RSTC_WRCFG_SET 0x00000030
32#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
33#define PM_RSTC_RESET 0x00000102
34
35#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
36#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
37
38struct bcm2835_wdt {
39 void __iomem *base;
40 spinlock_t lock;
41};
42
43static unsigned int heartbeat;
44static bool nowayout = WATCHDOG_NOWAYOUT;
45
46static int bcm2835_wdt_start(struct watchdog_device *wdog)
47{
48 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
49 uint32_t cur;
50 unsigned long flags;
51
52 spin_lock_irqsave(&wdt->lock, flags);
53
54 writel_relaxed(PM_PASSWORD | (SECS_TO_WDOG_TICKS(wdog->timeout) &
55 PM_WDOG_TIME_SET), wdt->base + PM_WDOG);
56 cur = readl_relaxed(wdt->base + PM_RSTC);
57 writel_relaxed(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) |
58 PM_RSTC_WRCFG_FULL_RESET, wdt->base + PM_RSTC);
59
60 spin_unlock_irqrestore(&wdt->lock, flags);
61
62 return 0;
63}
64
65static int bcm2835_wdt_stop(struct watchdog_device *wdog)
66{
67 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
68
69 writel_relaxed(PM_PASSWORD | PM_RSTC_RESET, wdt->base + PM_RSTC);
70 dev_info(wdog->dev, "Watchdog timer stopped");
71 return 0;
72}
73
74static int bcm2835_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
75{
76 wdog->timeout = t;
77 return 0;
78}
79
80static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog)
81{
82 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
83
84 uint32_t ret = readl_relaxed(wdt->base + PM_WDOG);
85 return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET);
86}
87
88static struct watchdog_ops bcm2835_wdt_ops = {
89 .owner = THIS_MODULE,
90 .start = bcm2835_wdt_start,
91 .stop = bcm2835_wdt_stop,
92 .set_timeout = bcm2835_wdt_set_timeout,
93 .get_timeleft = bcm2835_wdt_get_timeleft,
94};
95
96static struct watchdog_info bcm2835_wdt_info = {
97 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
98 WDIOF_KEEPALIVEPING,
99 .identity = "Broadcom BCM2835 Watchdog timer",
100};
101
102static struct watchdog_device bcm2835_wdt_wdd = {
103 .info = &bcm2835_wdt_info,
104 .ops = &bcm2835_wdt_ops,
105 .min_timeout = 1,
106 .max_timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
107 .timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
108};
109
110static int bcm2835_wdt_probe(struct platform_device *pdev)
111{
112 struct device *dev = &pdev->dev;
113 struct device_node *np = dev->of_node;
114 struct bcm2835_wdt *wdt;
115 int err;
116
117 wdt = devm_kzalloc(dev, sizeof(struct bcm2835_wdt), GFP_KERNEL);
118 if (!wdt) {
119 dev_err(dev, "Failed to allocate memory for watchdog device");
120 return -ENOMEM;
121 }
122 platform_set_drvdata(pdev, wdt);
123
124 spin_lock_init(&wdt->lock);
125
126 wdt->base = of_iomap(np, 0);
127 if (!wdt->base) {
128 dev_err(dev, "Failed to remap watchdog regs");
129 return -ENODEV;
130 }
131
132 watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt);
133 watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
134 watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout);
135 err = watchdog_register_device(&bcm2835_wdt_wdd);
136 if (err) {
137 dev_err(dev, "Failed to register watchdog device");
138 iounmap(wdt->base);
139 return err;
140 }
141
142 dev_info(dev, "Broadcom BCM2835 watchdog timer");
143 return 0;
144}
145
146static int bcm2835_wdt_remove(struct platform_device *pdev)
147{
148 struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
149
150 watchdog_unregister_device(&bcm2835_wdt_wdd);
151 iounmap(wdt->base);
152
153 return 0;
154}
155
156static void bcm2835_wdt_shutdown(struct platform_device *pdev)
157{
158 bcm2835_wdt_stop(&bcm2835_wdt_wdd);
159}
160
161static const struct of_device_id bcm2835_wdt_of_match[] = {
162 { .compatible = "brcm,bcm2835-pm-wdt", },
163 {},
164};
165MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match);
166
167static struct platform_driver bcm2835_wdt_driver = {
168 .probe = bcm2835_wdt_probe,
169 .remove = bcm2835_wdt_remove,
170 .shutdown = bcm2835_wdt_shutdown,
171 .driver = {
172 .name = "bcm2835-wdt",
173 .owner = THIS_MODULE,
174 .of_match_table = bcm2835_wdt_of_match,
175 },
176};
177module_platform_driver(bcm2835_wdt_driver);
178
179module_param(heartbeat, uint, 0);
180MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
181
182module_param(nowayout, bool, 0);
183MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
184 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
185
186MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
187MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer");
188MODULE_LICENSE("GPL");