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c36a483d WBG |
1 | /* |
2 | * Watchdog timer driver for the WinSystems EBC-C384 | |
3 | * Copyright (C) 2016 William Breathitt Gray | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License, version 2, as | |
7 | * published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, but | |
10 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | * General Public License for more details. | |
13 | */ | |
14 | #include <linux/device.h> | |
15 | #include <linux/dmi.h> | |
16 | #include <linux/errno.h> | |
17 | #include <linux/io.h> | |
18 | #include <linux/ioport.h> | |
4ef1bec4 | 19 | #include <linux/isa.h> |
c36a483d WBG |
20 | #include <linux/kernel.h> |
21 | #include <linux/module.h> | |
22 | #include <linux/moduleparam.h> | |
c36a483d WBG |
23 | #include <linux/types.h> |
24 | #include <linux/watchdog.h> | |
25 | ||
26 | #define MODULE_NAME "ebc-c384_wdt" | |
27 | #define WATCHDOG_TIMEOUT 60 | |
28 | /* | |
29 | * The timeout value in minutes must fit in a single byte when sent to the | |
30 | * watchdog timer; the maximum timeout possible is 15300 (255 * 60) seconds. | |
31 | */ | |
32 | #define WATCHDOG_MAX_TIMEOUT 15300 | |
33 | #define BASE_ADDR 0x564 | |
34 | #define ADDR_EXTENT 5 | |
35 | #define CFG_ADDR (BASE_ADDR + 1) | |
36 | #define PET_ADDR (BASE_ADDR + 2) | |
37 | ||
38 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
39 | module_param(nowayout, bool, 0); | |
40 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" | |
41 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
42 | ||
43 | static unsigned timeout; | |
44 | module_param(timeout, uint, 0); | |
45 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" | |
46 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
47 | ||
48 | static int ebc_c384_wdt_start(struct watchdog_device *wdev) | |
49 | { | |
50 | unsigned t = wdev->timeout; | |
51 | ||
52 | /* resolution is in minutes for timeouts greater than 255 seconds */ | |
53 | if (t > 255) | |
54 | t = DIV_ROUND_UP(t, 60); | |
55 | ||
56 | outb(t, PET_ADDR); | |
57 | ||
58 | return 0; | |
59 | } | |
60 | ||
61 | static int ebc_c384_wdt_stop(struct watchdog_device *wdev) | |
62 | { | |
63 | outb(0x00, PET_ADDR); | |
64 | ||
65 | return 0; | |
66 | } | |
67 | ||
68 | static int ebc_c384_wdt_set_timeout(struct watchdog_device *wdev, unsigned t) | |
69 | { | |
70 | /* resolution is in minutes for timeouts greater than 255 seconds */ | |
71 | if (t > 255) { | |
72 | /* round second resolution up to minute granularity */ | |
73 | wdev->timeout = roundup(t, 60); | |
74 | ||
75 | /* set watchdog timer for minutes */ | |
76 | outb(0x00, CFG_ADDR); | |
77 | } else { | |
78 | wdev->timeout = t; | |
79 | ||
80 | /* set watchdog timer for seconds */ | |
81 | outb(0x80, CFG_ADDR); | |
82 | } | |
83 | ||
84 | return 0; | |
85 | } | |
86 | ||
87 | static const struct watchdog_ops ebc_c384_wdt_ops = { | |
88 | .start = ebc_c384_wdt_start, | |
89 | .stop = ebc_c384_wdt_stop, | |
90 | .set_timeout = ebc_c384_wdt_set_timeout | |
91 | }; | |
92 | ||
93 | static const struct watchdog_info ebc_c384_wdt_info = { | |
94 | .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT, | |
95 | .identity = MODULE_NAME | |
96 | }; | |
97 | ||
4ef1bec4 | 98 | static int ebc_c384_wdt_probe(struct device *dev, unsigned int id) |
c36a483d | 99 | { |
c36a483d WBG |
100 | struct watchdog_device *wdd; |
101 | ||
102 | if (!devm_request_region(dev, BASE_ADDR, ADDR_EXTENT, dev_name(dev))) { | |
103 | dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n", | |
104 | BASE_ADDR, BASE_ADDR + ADDR_EXTENT); | |
105 | return -EBUSY; | |
106 | } | |
107 | ||
108 | wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL); | |
109 | if (!wdd) | |
110 | return -ENOMEM; | |
111 | ||
112 | wdd->info = &ebc_c384_wdt_info; | |
113 | wdd->ops = &ebc_c384_wdt_ops; | |
114 | wdd->timeout = WATCHDOG_TIMEOUT; | |
115 | wdd->min_timeout = 1; | |
116 | wdd->max_timeout = WATCHDOG_MAX_TIMEOUT; | |
117 | ||
118 | watchdog_set_nowayout(wdd, nowayout); | |
119 | ||
120 | if (watchdog_init_timeout(wdd, timeout, dev)) | |
121 | dev_warn(dev, "Invalid timeout (%u seconds), using default (%u seconds)\n", | |
122 | timeout, WATCHDOG_TIMEOUT); | |
123 | ||
4ef1bec4 | 124 | dev_set_drvdata(dev, wdd); |
c36a483d WBG |
125 | |
126 | return watchdog_register_device(wdd); | |
127 | } | |
128 | ||
4ef1bec4 | 129 | static int ebc_c384_wdt_remove(struct device *dev, unsigned int id) |
c36a483d | 130 | { |
4ef1bec4 | 131 | struct watchdog_device *wdd = dev_get_drvdata(dev); |
c36a483d WBG |
132 | |
133 | watchdog_unregister_device(wdd); | |
134 | ||
135 | return 0; | |
136 | } | |
137 | ||
4ef1bec4 WBG |
138 | static struct isa_driver ebc_c384_wdt_driver = { |
139 | .probe = ebc_c384_wdt_probe, | |
c36a483d WBG |
140 | .driver = { |
141 | .name = MODULE_NAME | |
142 | }, | |
143 | .remove = ebc_c384_wdt_remove | |
144 | }; | |
145 | ||
c36a483d WBG |
146 | static int __init ebc_c384_wdt_init(void) |
147 | { | |
c36a483d WBG |
148 | if (!dmi_match(DMI_BOARD_NAME, "EBC-C384 SBC")) |
149 | return -ENODEV; | |
150 | ||
4ef1bec4 | 151 | return isa_register_driver(&ebc_c384_wdt_driver, 1); |
c36a483d WBG |
152 | } |
153 | ||
154 | static void __exit ebc_c384_wdt_exit(void) | |
155 | { | |
4ef1bec4 | 156 | isa_unregister_driver(&ebc_c384_wdt_driver); |
c36a483d WBG |
157 | } |
158 | ||
159 | module_init(ebc_c384_wdt_init); | |
160 | module_exit(ebc_c384_wdt_exit); | |
161 | ||
162 | MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); | |
163 | MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver"); | |
164 | MODULE_LICENSE("GPL v2"); | |
4ef1bec4 | 165 | MODULE_ALIAS("isa:" MODULE_NAME); |