xref: /openbmc/linux/drivers/watchdog/tqmx86_wdt.c (revision 625e407c)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Watchdog driver for TQMx86 PLD.
4  *
5  * The watchdog supports power of 2 timeouts from 1 to 4096sec.
6  * Once started, it cannot be stopped.
7  *
8  * Based on the vendor code written by Vadim V.Vlasov
9  * <vvlasov@dev.rtsoft.ru>
10  */
11 
12 #include <linux/io.h>
13 #include <linux/log2.h>
14 #include <linux/module.h>
15 #include <linux/platform_device.h>
16 #include <linux/timer.h>
17 #include <linux/watchdog.h>
18 
19 /* default timeout (secs) */
20 #define WDT_TIMEOUT 32
21 
22 static unsigned int timeout;
23 module_param(timeout, uint, 0);
24 MODULE_PARM_DESC(timeout,
25 	"Watchdog timeout in seconds. (1<=timeout<=4096, default="
26 				__MODULE_STRING(WDT_TIMEOUT) ")");
27 struct tqmx86_wdt {
28 	struct watchdog_device wdd;
29 	void __iomem *io_base;
30 };
31 
32 #define TQMX86_WDCFG	0x00 /* Watchdog Configuration Register */
33 #define TQMX86_WDCS	0x01 /* Watchdog Config/Status Register */
34 
tqmx86_wdt_start(struct watchdog_device * wdd)35 static int tqmx86_wdt_start(struct watchdog_device *wdd)
36 {
37 	struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);
38 
39 	iowrite8(0x81, priv->io_base + TQMX86_WDCS);
40 
41 	return 0;
42 }
43 
tqmx86_wdt_set_timeout(struct watchdog_device * wdd,unsigned int t)44 static int tqmx86_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
45 {
46 	struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);
47 	u8 val;
48 
49 	t = roundup_pow_of_two(t);
50 	val = ilog2(t) | 0x90;
51 	val += 3; /* values 0,1,2 correspond to 0.125,0.25,0.5s timeouts */
52 	iowrite8(val, priv->io_base + TQMX86_WDCFG);
53 
54 	wdd->timeout = t;
55 
56 	return 0;
57 }
58 
59 static const struct watchdog_info tqmx86_wdt_info = {
60 	.options	= WDIOF_SETTIMEOUT |
61 			  WDIOF_KEEPALIVEPING,
62 	.identity	= "TQMx86 Watchdog",
63 };
64 
65 static const struct watchdog_ops tqmx86_wdt_ops = {
66 	.owner		= THIS_MODULE,
67 	.start		= tqmx86_wdt_start,
68 	.set_timeout	= tqmx86_wdt_set_timeout,
69 };
70 
tqmx86_wdt_probe(struct platform_device * pdev)71 static int tqmx86_wdt_probe(struct platform_device *pdev)
72 {
73 	struct device *dev = &pdev->dev;
74 	struct tqmx86_wdt *priv;
75 	struct resource *res;
76 	int err;
77 
78 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
79 	if (!priv)
80 		return -ENOMEM;
81 
82 	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
83 	if (!res)
84 		return -ENODEV;
85 
86 	priv->io_base = devm_ioport_map(dev, res->start, resource_size(res));
87 	if (!priv->io_base)
88 		return -ENOMEM;
89 
90 	watchdog_set_drvdata(&priv->wdd, priv);
91 
92 	priv->wdd.parent = dev;
93 	priv->wdd.info = &tqmx86_wdt_info;
94 	priv->wdd.ops = &tqmx86_wdt_ops;
95 	priv->wdd.min_timeout = 1;
96 	priv->wdd.max_timeout = 4096;
97 	priv->wdd.max_hw_heartbeat_ms = 4096*1000;
98 	priv->wdd.timeout = WDT_TIMEOUT;
99 
100 	watchdog_init_timeout(&priv->wdd, timeout, dev);
101 	watchdog_set_nowayout(&priv->wdd, WATCHDOG_NOWAYOUT);
102 
103 	tqmx86_wdt_set_timeout(&priv->wdd, priv->wdd.timeout);
104 
105 	err = devm_watchdog_register_device(dev, &priv->wdd);
106 	if (err)
107 		return err;
108 
109 	dev_info(dev, "TQMx86 watchdog\n");
110 
111 	return 0;
112 }
113 
114 static struct platform_driver tqmx86_wdt_driver = {
115 	.driver		= {
116 		.name	= "tqmx86-wdt",
117 	},
118 	.probe		= tqmx86_wdt_probe,
119 };
120 
121 module_platform_driver(tqmx86_wdt_driver);
122 
123 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
124 MODULE_DESCRIPTION("TQMx86 Watchdog");
125 MODULE_ALIAS("platform:tqmx86-wdt");
126 MODULE_LICENSE("GPL");
127