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2e62c498 | 1 | // SPDX-License-Identifier: GPL-2.0 |
c36a483d WBG |
2 | /* |
3 | * Watchdog timer driver for the WinSystems EBC-C384 | |
4 | * Copyright (C) 2016 William Breathitt Gray | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License, version 2, as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, but | |
11 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | * General Public License for more details. | |
14 | */ | |
15 | #include <linux/device.h> | |
16 | #include <linux/dmi.h> | |
17 | #include <linux/errno.h> | |
18 | #include <linux/io.h> | |
19 | #include <linux/ioport.h> | |
4ef1bec4 | 20 | #include <linux/isa.h> |
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21 | #include <linux/kernel.h> |
22 | #include <linux/module.h> | |
23 | #include <linux/moduleparam.h> | |
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24 | #include <linux/types.h> |
25 | #include <linux/watchdog.h> | |
26 | ||
27 | #define MODULE_NAME "ebc-c384_wdt" | |
28 | #define WATCHDOG_TIMEOUT 60 | |
29 | /* | |
30 | * The timeout value in minutes must fit in a single byte when sent to the | |
31 | * watchdog timer; the maximum timeout possible is 15300 (255 * 60) seconds. | |
32 | */ | |
33 | #define WATCHDOG_MAX_TIMEOUT 15300 | |
34 | #define BASE_ADDR 0x564 | |
35 | #define ADDR_EXTENT 5 | |
36 | #define CFG_ADDR (BASE_ADDR + 1) | |
37 | #define PET_ADDR (BASE_ADDR + 2) | |
38 | ||
39 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
40 | module_param(nowayout, bool, 0); | |
41 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" | |
42 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
43 | ||
44 | static unsigned timeout; | |
45 | module_param(timeout, uint, 0); | |
46 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" | |
47 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
48 | ||
49 | static int ebc_c384_wdt_start(struct watchdog_device *wdev) | |
50 | { | |
51 | unsigned t = wdev->timeout; | |
52 | ||
53 | /* resolution is in minutes for timeouts greater than 255 seconds */ | |
54 | if (t > 255) | |
55 | t = DIV_ROUND_UP(t, 60); | |
56 | ||
57 | outb(t, PET_ADDR); | |
58 | ||
59 | return 0; | |
60 | } | |
61 | ||
62 | static int ebc_c384_wdt_stop(struct watchdog_device *wdev) | |
63 | { | |
64 | outb(0x00, PET_ADDR); | |
65 | ||
66 | return 0; | |
67 | } | |
68 | ||
69 | static int ebc_c384_wdt_set_timeout(struct watchdog_device *wdev, unsigned t) | |
70 | { | |
71 | /* resolution is in minutes for timeouts greater than 255 seconds */ | |
72 | if (t > 255) { | |
73 | /* round second resolution up to minute granularity */ | |
74 | wdev->timeout = roundup(t, 60); | |
75 | ||
76 | /* set watchdog timer for minutes */ | |
77 | outb(0x00, CFG_ADDR); | |
78 | } else { | |
79 | wdev->timeout = t; | |
80 | ||
81 | /* set watchdog timer for seconds */ | |
82 | outb(0x80, CFG_ADDR); | |
83 | } | |
84 | ||
85 | return 0; | |
86 | } | |
87 | ||
88 | static const struct watchdog_ops ebc_c384_wdt_ops = { | |
89 | .start = ebc_c384_wdt_start, | |
90 | .stop = ebc_c384_wdt_stop, | |
91 | .set_timeout = ebc_c384_wdt_set_timeout | |
92 | }; | |
93 | ||
94 | static const struct watchdog_info ebc_c384_wdt_info = { | |
95 | .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT, | |
96 | .identity = MODULE_NAME | |
97 | }; | |
98 | ||
4ef1bec4 | 99 | static int ebc_c384_wdt_probe(struct device *dev, unsigned int id) |
c36a483d | 100 | { |
c36a483d WBG |
101 | struct watchdog_device *wdd; |
102 | ||
103 | if (!devm_request_region(dev, BASE_ADDR, ADDR_EXTENT, dev_name(dev))) { | |
104 | dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n", | |
105 | BASE_ADDR, BASE_ADDR + ADDR_EXTENT); | |
106 | return -EBUSY; | |
107 | } | |
108 | ||
109 | wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL); | |
110 | if (!wdd) | |
111 | return -ENOMEM; | |
112 | ||
113 | wdd->info = &ebc_c384_wdt_info; | |
114 | wdd->ops = &ebc_c384_wdt_ops; | |
115 | wdd->timeout = WATCHDOG_TIMEOUT; | |
116 | wdd->min_timeout = 1; | |
117 | wdd->max_timeout = WATCHDOG_MAX_TIMEOUT; | |
118 | ||
119 | watchdog_set_nowayout(wdd, nowayout); | |
120 | ||
121 | if (watchdog_init_timeout(wdd, timeout, dev)) | |
122 | dev_warn(dev, "Invalid timeout (%u seconds), using default (%u seconds)\n", | |
123 | timeout, WATCHDOG_TIMEOUT); | |
124 | ||
540aea3d | 125 | return devm_watchdog_register_device(dev, wdd); |
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126 | } |
127 | ||
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128 | static struct isa_driver ebc_c384_wdt_driver = { |
129 | .probe = ebc_c384_wdt_probe, | |
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130 | .driver = { |
131 | .name = MODULE_NAME | |
132 | }, | |
c36a483d WBG |
133 | }; |
134 | ||
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135 | static int __init ebc_c384_wdt_init(void) |
136 | { | |
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137 | if (!dmi_match(DMI_BOARD_NAME, "EBC-C384 SBC")) |
138 | return -ENODEV; | |
139 | ||
4ef1bec4 | 140 | return isa_register_driver(&ebc_c384_wdt_driver, 1); |
c36a483d WBG |
141 | } |
142 | ||
143 | static void __exit ebc_c384_wdt_exit(void) | |
144 | { | |
4ef1bec4 | 145 | isa_unregister_driver(&ebc_c384_wdt_driver); |
c36a483d WBG |
146 | } |
147 | ||
148 | module_init(ebc_c384_wdt_init); | |
149 | module_exit(ebc_c384_wdt_exit); | |
150 | ||
151 | MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); | |
152 | MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver"); | |
153 | MODULE_LICENSE("GPL v2"); | |
4ef1bec4 | 154 | MODULE_ALIAS("isa:" MODULE_NAME); |