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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>
Lubomir Rintel938d0a82013-06-18 19:44:48 +020022
23#define PM_RSTC 0x1c
24#define PM_WDOG 0x24
25
26#define PM_PASSWORD 0x5a000000
27
28#define PM_WDOG_TIME_SET 0x000fffff
29#define PM_RSTC_WRCFG_CLR 0xffffffcf
30#define PM_RSTC_WRCFG_SET 0x00000030
31#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
32#define PM_RSTC_RESET 0x00000102
33
34#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
35#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
36
37struct bcm2835_wdt {
38 void __iomem *base;
39 spinlock_t lock;
40};
41
42static unsigned int heartbeat;
43static bool nowayout = WATCHDOG_NOWAYOUT;
44
45static int bcm2835_wdt_start(struct watchdog_device *wdog)
46{
47 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
48 uint32_t cur;
49 unsigned long flags;
50
51 spin_lock_irqsave(&wdt->lock, flags);
52
53 writel_relaxed(PM_PASSWORD | (SECS_TO_WDOG_TICKS(wdog->timeout) &
54 PM_WDOG_TIME_SET), wdt->base + PM_WDOG);
55 cur = readl_relaxed(wdt->base + PM_RSTC);
56 writel_relaxed(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) |
57 PM_RSTC_WRCFG_FULL_RESET, wdt->base + PM_RSTC);
58
59 spin_unlock_irqrestore(&wdt->lock, flags);
60
61 return 0;
62}
63
64static int bcm2835_wdt_stop(struct watchdog_device *wdog)
65{
66 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
67
68 writel_relaxed(PM_PASSWORD | PM_RSTC_RESET, wdt->base + PM_RSTC);
69 dev_info(wdog->dev, "Watchdog timer stopped");
70 return 0;
71}
72
73static int bcm2835_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
74{
75 wdog->timeout = t;
76 return 0;
77}
78
79static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog)
80{
81 struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
82
83 uint32_t ret = readl_relaxed(wdt->base + PM_WDOG);
84 return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET);
85}
86
87static struct watchdog_ops bcm2835_wdt_ops = {
88 .owner = THIS_MODULE,
89 .start = bcm2835_wdt_start,
90 .stop = bcm2835_wdt_stop,
91 .set_timeout = bcm2835_wdt_set_timeout,
92 .get_timeleft = bcm2835_wdt_get_timeleft,
93};
94
95static struct watchdog_info bcm2835_wdt_info = {
96 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
97 WDIOF_KEEPALIVEPING,
98 .identity = "Broadcom BCM2835 Watchdog timer",
99};
100
101static struct watchdog_device bcm2835_wdt_wdd = {
102 .info = &bcm2835_wdt_info,
103 .ops = &bcm2835_wdt_ops,
104 .min_timeout = 1,
105 .max_timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
106 .timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
107};
108
109static int bcm2835_wdt_probe(struct platform_device *pdev)
110{
111 struct device *dev = &pdev->dev;
112 struct device_node *np = dev->of_node;
113 struct bcm2835_wdt *wdt;
114 int err;
115
116 wdt = devm_kzalloc(dev, sizeof(struct bcm2835_wdt), GFP_KERNEL);
Jingoo Han8deea832014-02-11 15:46:43 +0900117 if (!wdt)
Lubomir Rintel938d0a82013-06-18 19:44:48 +0200118 return -ENOMEM;
Lubomir Rintel938d0a82013-06-18 19:44:48 +0200119 platform_set_drvdata(pdev, wdt);
120
121 spin_lock_init(&wdt->lock);
122
123 wdt->base = of_iomap(np, 0);
124 if (!wdt->base) {
125 dev_err(dev, "Failed to remap watchdog regs");
126 return -ENODEV;
127 }
128
129 watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt);
130 watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
131 watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout);
132 err = watchdog_register_device(&bcm2835_wdt_wdd);
133 if (err) {
134 dev_err(dev, "Failed to register watchdog device");
135 iounmap(wdt->base);
136 return err;
137 }
138
139 dev_info(dev, "Broadcom BCM2835 watchdog timer");
140 return 0;
141}
142
143static int bcm2835_wdt_remove(struct platform_device *pdev)
144{
145 struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
146
147 watchdog_unregister_device(&bcm2835_wdt_wdd);
148 iounmap(wdt->base);
149
150 return 0;
151}
152
153static void bcm2835_wdt_shutdown(struct platform_device *pdev)
154{
155 bcm2835_wdt_stop(&bcm2835_wdt_wdd);
156}
157
158static const struct of_device_id bcm2835_wdt_of_match[] = {
159 { .compatible = "brcm,bcm2835-pm-wdt", },
160 {},
161};
162MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match);
163
164static struct platform_driver bcm2835_wdt_driver = {
165 .probe = bcm2835_wdt_probe,
166 .remove = bcm2835_wdt_remove,
167 .shutdown = bcm2835_wdt_shutdown,
168 .driver = {
169 .name = "bcm2835-wdt",
Lubomir Rintel938d0a82013-06-18 19:44:48 +0200170 .of_match_table = bcm2835_wdt_of_match,
171 },
172};
173module_platform_driver(bcm2835_wdt_driver);
174
175module_param(heartbeat, uint, 0);
176MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
177
178module_param(nowayout, bool, 0);
179MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
180 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
181
182MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
183MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer");
184MODULE_LICENSE("GPL");