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 | |
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 | |
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 | |
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, size: 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, port: res->start, nr: resource_size(res)); |
87 | if (!priv->io_base) |
88 | return -ENOMEM; |
89 | |
90 | watchdog_set_drvdata(wdd: &priv->wdd, data: 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(wdd: &priv->wdd, timeout_parm: timeout, dev); |
101 | watchdog_set_nowayout(wdd: &priv->wdd, WATCHDOG_NOWAYOUT); |
102 | |
103 | tqmx86_wdt_set_timeout(wdd: &priv->wdd, t: 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 | |