1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Watchdog timer driver for the WinSystems EBC-C384 |
4 | * Copyright (C) 2016 William Breathitt Gray |
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> |
11 | #include <linux/isa.h> |
12 | #include <linux/kernel.h> |
13 | #include <linux/module.h> |
14 | #include <linux/moduleparam.h> |
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(value: t, PET_ADDR); |
49 | |
50 | return 0; |
51 | } |
52 | |
53 | static int ebc_c384_wdt_stop(struct watchdog_device *wdev) |
54 | { |
55 | outb(value: 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(value: 0x00, CFG_ADDR); |
69 | } else { |
70 | wdev->timeout = t; |
71 | |
72 | /* set watchdog timer for seconds */ |
73 | outb(value: 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 | |
90 | static int ebc_c384_wdt_probe(struct device *dev, unsigned int id) |
91 | { |
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, size: 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); |
111 | watchdog_init_timeout(wdd, timeout_parm: timeout, dev); |
112 | |
113 | return devm_watchdog_register_device(dev, wdd); |
114 | } |
115 | |
116 | static struct isa_driver ebc_c384_wdt_driver = { |
117 | .probe = ebc_c384_wdt_probe, |
118 | .driver = { |
119 | .name = MODULE_NAME |
120 | }, |
121 | }; |
122 | |
123 | static int __init ebc_c384_wdt_init(void) |
124 | { |
125 | if (!dmi_match(f: DMI_BOARD_NAME, str: "EBC-C384 SBC" )) |
126 | return -ENODEV; |
127 | |
128 | return isa_register_driver(&ebc_c384_wdt_driver, 1); |
129 | } |
130 | |
131 | static void __exit ebc_c384_wdt_exit(void) |
132 | { |
133 | isa_unregister_driver(&ebc_c384_wdt_driver); |
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" ); |
142 | MODULE_ALIAS("isa:" MODULE_NAME); |
143 | |