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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 | |
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5 | */ |
6 | #include <linux/device.h> | |
7 | #include <linux/dmi.h> | |
8 | #include <linux/errno.h> | |
9 | #include <linux/io.h> | |
10 | #include <linux/ioport.h> | |
4ef1bec4 | 11 | #include <linux/isa.h> |
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12 | #include <linux/kernel.h> |
13 | #include <linux/module.h> | |
14 | #include <linux/moduleparam.h> | |
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15 | #include <linux/types.h> |
16 | #include <linux/watchdog.h> | |
17 | ||
18 | #define MODULE_NAME "ebc-c384_wdt" | |
19 | #define WATCHDOG_TIMEOUT 60 | |
20 | /* | |
21 | * The timeout value in minutes must fit in a single byte when sent to the | |
22 | * watchdog timer; the maximum timeout possible is 15300 (255 * 60) seconds. | |
23 | */ | |
24 | #define WATCHDOG_MAX_TIMEOUT 15300 | |
25 | #define BASE_ADDR 0x564 | |
26 | #define ADDR_EXTENT 5 | |
27 | #define CFG_ADDR (BASE_ADDR + 1) | |
28 | #define PET_ADDR (BASE_ADDR + 2) | |
29 | ||
30 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
31 | module_param(nowayout, bool, 0); | |
32 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" | |
33 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
34 | ||
35 | static unsigned timeout; | |
36 | module_param(timeout, uint, 0); | |
37 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" | |
38 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
39 | ||
40 | static int ebc_c384_wdt_start(struct watchdog_device *wdev) | |
41 | { | |
42 | unsigned t = wdev->timeout; | |
43 | ||
44 | /* resolution is in minutes for timeouts greater than 255 seconds */ | |
45 | if (t > 255) | |
46 | t = DIV_ROUND_UP(t, 60); | |
47 | ||
48 | outb(t, PET_ADDR); | |
49 | ||
50 | return 0; | |
51 | } | |
52 | ||
53 | static int ebc_c384_wdt_stop(struct watchdog_device *wdev) | |
54 | { | |
55 | outb(0x00, PET_ADDR); | |
56 | ||
57 | return 0; | |
58 | } | |
59 | ||
60 | static int ebc_c384_wdt_set_timeout(struct watchdog_device *wdev, unsigned t) | |
61 | { | |
62 | /* resolution is in minutes for timeouts greater than 255 seconds */ | |
63 | if (t > 255) { | |
64 | /* round second resolution up to minute granularity */ | |
65 | wdev->timeout = roundup(t, 60); | |
66 | ||
67 | /* set watchdog timer for minutes */ | |
68 | outb(0x00, CFG_ADDR); | |
69 | } else { | |
70 | wdev->timeout = t; | |
71 | ||
72 | /* set watchdog timer for seconds */ | |
73 | outb(0x80, CFG_ADDR); | |
74 | } | |
75 | ||
76 | return 0; | |
77 | } | |
78 | ||
79 | static const struct watchdog_ops ebc_c384_wdt_ops = { | |
80 | .start = ebc_c384_wdt_start, | |
81 | .stop = ebc_c384_wdt_stop, | |
82 | .set_timeout = ebc_c384_wdt_set_timeout | |
83 | }; | |
84 | ||
85 | static const struct watchdog_info ebc_c384_wdt_info = { | |
86 | .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT, | |
87 | .identity = MODULE_NAME | |
88 | }; | |
89 | ||
4ef1bec4 | 90 | static int ebc_c384_wdt_probe(struct device *dev, unsigned int id) |
c36a483d | 91 | { |
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92 | struct watchdog_device *wdd; |
93 | ||
94 | if (!devm_request_region(dev, BASE_ADDR, ADDR_EXTENT, dev_name(dev))) { | |
95 | dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n", | |
96 | BASE_ADDR, BASE_ADDR + ADDR_EXTENT); | |
97 | return -EBUSY; | |
98 | } | |
99 | ||
100 | wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL); | |
101 | if (!wdd) | |
102 | return -ENOMEM; | |
103 | ||
104 | wdd->info = &ebc_c384_wdt_info; | |
105 | wdd->ops = &ebc_c384_wdt_ops; | |
106 | wdd->timeout = WATCHDOG_TIMEOUT; | |
107 | wdd->min_timeout = 1; | |
108 | wdd->max_timeout = WATCHDOG_MAX_TIMEOUT; | |
109 | ||
110 | watchdog_set_nowayout(wdd, nowayout); | |
cccbf8ba | 111 | watchdog_init_timeout(wdd, timeout, dev); |
c36a483d | 112 | |
540aea3d | 113 | return devm_watchdog_register_device(dev, wdd); |
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114 | } |
115 | ||
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116 | static struct isa_driver ebc_c384_wdt_driver = { |
117 | .probe = ebc_c384_wdt_probe, | |
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118 | .driver = { |
119 | .name = MODULE_NAME | |
120 | }, | |
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121 | }; |
122 | ||
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123 | static int __init ebc_c384_wdt_init(void) |
124 | { | |
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125 | if (!dmi_match(DMI_BOARD_NAME, "EBC-C384 SBC")) |
126 | return -ENODEV; | |
127 | ||
4ef1bec4 | 128 | return isa_register_driver(&ebc_c384_wdt_driver, 1); |
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129 | } |
130 | ||
131 | static void __exit ebc_c384_wdt_exit(void) | |
132 | { | |
4ef1bec4 | 133 | isa_unregister_driver(&ebc_c384_wdt_driver); |
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134 | } |
135 | ||
136 | module_init(ebc_c384_wdt_init); | |
137 | module_exit(ebc_c384_wdt_exit); | |
138 | ||
139 | MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); | |
140 | MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver"); | |
141 | MODULE_LICENSE("GPL v2"); | |
4ef1bec4 | 142 | MODULE_ALIAS("isa:" MODULE_NAME); |