1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) ST-Ericsson SA 2011-2013
4  *
5  * Author: Mathieu Poirier <mathieu.poirier@linaro.org> for ST-Ericsson
6  * Author: Jonas Aaberg <jonas.aberg@stericsson.com> for ST-Ericsson
7  */
8 
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 
11 #include <linux/module.h>
12 #include <linux/kernel.h>
13 #include <linux/moduleparam.h>
14 #include <linux/err.h>
15 #include <linux/uaccess.h>
16 #include <linux/watchdog.h>
17 #include <linux/platform_device.h>
18 
19 #include <linux/mfd/dbx500-prcmu.h>
20 
21 #define WATCHDOG_TIMEOUT 600 /* 10 minutes */
22 
23 #define WATCHDOG_MIN	0
24 #define WATCHDOG_MAX28	268435  /* 28 bit resolution in ms == 268435.455 s */
25 
26 static unsigned int timeout = WATCHDOG_TIMEOUT;
27 module_param(timeout, uint, 0);
28 MODULE_PARM_DESC(timeout,
29 	"Watchdog timeout in seconds. default="
30 				__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
31 
32 static bool nowayout = WATCHDOG_NOWAYOUT;
33 module_param(nowayout, bool, 0);
34 MODULE_PARM_DESC(nowayout,
35 	"Watchdog cannot be stopped once started (default="
36 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
37 
db8500_wdt_start(struct watchdog_device * wdd)38 static int db8500_wdt_start(struct watchdog_device *wdd)
39 {
40 	return prcmu_enable_a9wdog(PRCMU_WDOG_ALL);
41 }
42 
db8500_wdt_stop(struct watchdog_device * wdd)43 static int db8500_wdt_stop(struct watchdog_device *wdd)
44 {
45 	return prcmu_disable_a9wdog(PRCMU_WDOG_ALL);
46 }
47 
db8500_wdt_keepalive(struct watchdog_device * wdd)48 static int db8500_wdt_keepalive(struct watchdog_device *wdd)
49 {
50 	return prcmu_kick_a9wdog(PRCMU_WDOG_ALL);
51 }
52 
db8500_wdt_set_timeout(struct watchdog_device * wdd,unsigned int timeout)53 static int db8500_wdt_set_timeout(struct watchdog_device *wdd,
54 				 unsigned int timeout)
55 {
56 	db8500_wdt_stop(wdd);
57 	prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
58 	db8500_wdt_start(wdd);
59 
60 	return 0;
61 }
62 
63 static const struct watchdog_info db8500_wdt_info = {
64 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
65 	.identity = "DB8500 WDT",
66 	.firmware_version = 1,
67 };
68 
69 static const struct watchdog_ops db8500_wdt_ops = {
70 	.owner = THIS_MODULE,
71 	.start = db8500_wdt_start,
72 	.stop  = db8500_wdt_stop,
73 	.ping  = db8500_wdt_keepalive,
74 	.set_timeout = db8500_wdt_set_timeout,
75 };
76 
77 static struct watchdog_device db8500_wdt = {
78 	.info = &db8500_wdt_info,
79 	.ops = &db8500_wdt_ops,
80 	.min_timeout = WATCHDOG_MIN,
81 	.max_timeout = WATCHDOG_MAX28,
82 };
83 
db8500_wdt_probe(struct platform_device * pdev)84 static int db8500_wdt_probe(struct platform_device *pdev)
85 {
86 	struct device *dev = &pdev->dev;
87 	int ret;
88 
89 	timeout = 600; /* Default to 10 minutes */
90 	db8500_wdt.parent = dev;
91 	watchdog_set_nowayout(&db8500_wdt, nowayout);
92 
93 	/* disable auto off on sleep */
94 	prcmu_config_a9wdog(PRCMU_WDOG_CPU1, false);
95 
96 	/* set HW initial value */
97 	prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
98 
99 	ret = devm_watchdog_register_device(dev, &db8500_wdt);
100 	if (ret)
101 		return ret;
102 
103 	dev_info(dev, "initialized\n");
104 
105 	return 0;
106 }
107 
108 #ifdef CONFIG_PM
db8500_wdt_suspend(struct platform_device * pdev,pm_message_t state)109 static int db8500_wdt_suspend(struct platform_device *pdev,
110 			     pm_message_t state)
111 {
112 	if (watchdog_active(&db8500_wdt)) {
113 		db8500_wdt_stop(&db8500_wdt);
114 		prcmu_config_a9wdog(PRCMU_WDOG_CPU1, true);
115 
116 		prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
117 		db8500_wdt_start(&db8500_wdt);
118 	}
119 	return 0;
120 }
121 
db8500_wdt_resume(struct platform_device * pdev)122 static int db8500_wdt_resume(struct platform_device *pdev)
123 {
124 	if (watchdog_active(&db8500_wdt)) {
125 		db8500_wdt_stop(&db8500_wdt);
126 		prcmu_config_a9wdog(PRCMU_WDOG_CPU1, false);
127 
128 		prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
129 		db8500_wdt_start(&db8500_wdt);
130 	}
131 	return 0;
132 }
133 #else
134 #define db8500_wdt_suspend NULL
135 #define db8500_wdt_resume NULL
136 #endif
137 
138 static struct platform_driver db8500_wdt_driver = {
139 	.probe		= db8500_wdt_probe,
140 	.suspend	= db8500_wdt_suspend,
141 	.resume		= db8500_wdt_resume,
142 	.driver		= {
143 		.name	= "db8500_wdt",
144 	},
145 };
146 
147 module_platform_driver(db8500_wdt_driver);
148 
149 MODULE_AUTHOR("Jonas Aaberg <jonas.aberg@stericsson.com>");
150 MODULE_DESCRIPTION("DB8500 Watchdog Driver");
151 MODULE_LICENSE("GPL");
152 MODULE_ALIAS("platform:db8500_wdt");
153