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938d0a84 LR |
1 | /* |
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 | ||
38 | struct bcm2835_wdt { | |
39 | void __iomem *base; | |
40 | spinlock_t lock; | |
41 | }; | |
42 | ||
43 | static unsigned int heartbeat; | |
44 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
45 | ||
46 | static 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 | ||
65 | static 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 | ||
74 | static int bcm2835_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) | |
75 | { | |
76 | wdog->timeout = t; | |
77 | return 0; | |
78 | } | |
79 | ||
80 | static 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 | ||
88 | static 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 | ||
96 | static struct watchdog_info bcm2835_wdt_info = { | |
97 | .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | | |
98 | WDIOF_KEEPALIVEPING, | |
99 | .identity = "Broadcom BCM2835 Watchdog timer", | |
100 | }; | |
101 | ||
102 | static 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 | ||
110 | static 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 | ||
146 | static 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 | ||
156 | static void bcm2835_wdt_shutdown(struct platform_device *pdev) | |
157 | { | |
158 | bcm2835_wdt_stop(&bcm2835_wdt_wdd); | |
159 | } | |
160 | ||
161 | static const struct of_device_id bcm2835_wdt_of_match[] = { | |
162 | { .compatible = "brcm,bcm2835-pm-wdt", }, | |
163 | {}, | |
164 | }; | |
165 | MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match); | |
166 | ||
167 | static 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 | }; | |
177 | module_platform_driver(bcm2835_wdt_driver); | |
178 | ||
179 | module_param(heartbeat, uint, 0); | |
180 | MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds"); | |
181 | ||
182 | module_param(nowayout, bool, 0); | |
183 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" | |
184 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
185 | ||
186 | MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>"); | |
187 | MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer"); | |
188 | MODULE_LICENSE("GPL"); | |
189 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |