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81ceed41 JT |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Watchdog driver for the MEN z069 IP-Core | |
4 | * | |
5 | * Copyright (C) 2018 Johannes Thumshirn <jth@kernel.org> | |
6 | */ | |
7 | #include <linux/io.h> | |
8 | #include <linux/kernel.h> | |
9 | #include <linux/mcb.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/watchdog.h> | |
12 | ||
13 | struct men_z069_drv { | |
14 | struct watchdog_device wdt; | |
15 | void __iomem *base; | |
16 | struct resource *mem; | |
17 | }; | |
18 | ||
19 | #define MEN_Z069_WTR 0x10 | |
20 | #define MEN_Z069_WTR_WDEN BIT(15) | |
21 | #define MEN_Z069_WTR_WDET_MASK 0x7fff | |
22 | #define MEN_Z069_WVR 0x14 | |
23 | ||
24 | #define MEN_Z069_TIMER_FREQ 500 /* 500 Hz */ | |
25 | #define MEN_Z069_WDT_COUNTER_MIN 1 | |
26 | #define MEN_Z069_WDT_COUNTER_MAX 0x7fff | |
27 | #define MEN_Z069_DEFAULT_TIMEOUT 30 | |
28 | ||
29 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
30 | module_param(nowayout, bool, 0); | |
31 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" | |
32 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
33 | ||
34 | static int men_z069_wdt_start(struct watchdog_device *wdt) | |
35 | { | |
36 | struct men_z069_drv *drv = watchdog_get_drvdata(wdt); | |
37 | u16 val; | |
38 | ||
39 | val = readw(drv->base + MEN_Z069_WTR); | |
40 | val |= MEN_Z069_WTR_WDEN; | |
41 | writew(val, drv->base + MEN_Z069_WTR); | |
42 | ||
43 | return 0; | |
44 | } | |
45 | ||
46 | static int men_z069_wdt_stop(struct watchdog_device *wdt) | |
47 | { | |
48 | struct men_z069_drv *drv = watchdog_get_drvdata(wdt); | |
49 | u16 val; | |
50 | ||
51 | val = readw(drv->base + MEN_Z069_WTR); | |
52 | val &= ~MEN_Z069_WTR_WDEN; | |
53 | writew(val, drv->base + MEN_Z069_WTR); | |
54 | ||
55 | return 0; | |
56 | } | |
57 | ||
58 | static int men_z069_wdt_ping(struct watchdog_device *wdt) | |
59 | { | |
60 | struct men_z069_drv *drv = watchdog_get_drvdata(wdt); | |
61 | u16 val; | |
62 | ||
63 | /* The watchdog trigger value toggles between 0x5555 and 0xaaaa */ | |
64 | val = readw(drv->base + MEN_Z069_WVR); | |
65 | val ^= 0xffff; | |
66 | writew(val, drv->base + MEN_Z069_WVR); | |
67 | ||
68 | return 0; | |
69 | } | |
70 | ||
71 | static int men_z069_wdt_set_timeout(struct watchdog_device *wdt, | |
72 | unsigned int timeout) | |
73 | { | |
74 | struct men_z069_drv *drv = watchdog_get_drvdata(wdt); | |
75 | u16 reg, val, ena; | |
76 | ||
77 | wdt->timeout = timeout; | |
78 | val = timeout * MEN_Z069_TIMER_FREQ; | |
79 | ||
80 | reg = readw(drv->base + MEN_Z069_WVR); | |
81 | ena = reg & MEN_Z069_WTR_WDEN; | |
82 | reg = ena | val; | |
83 | writew(reg, drv->base + MEN_Z069_WTR); | |
84 | ||
85 | return 0; | |
86 | } | |
87 | ||
88 | static const struct watchdog_info men_z069_info = { | |
89 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, | |
90 | .identity = "MEN z069 Watchdog", | |
91 | }; | |
92 | ||
93 | static const struct watchdog_ops men_z069_ops = { | |
94 | .owner = THIS_MODULE, | |
95 | .start = men_z069_wdt_start, | |
96 | .stop = men_z069_wdt_stop, | |
97 | .ping = men_z069_wdt_ping, | |
98 | .set_timeout = men_z069_wdt_set_timeout, | |
99 | }; | |
100 | ||
101 | static struct watchdog_device men_z069_wdt = { | |
102 | .info = &men_z069_info, | |
103 | .ops = &men_z069_ops, | |
104 | .timeout = MEN_Z069_DEFAULT_TIMEOUT, | |
105 | .min_timeout = 1, | |
106 | .max_timeout = MEN_Z069_WDT_COUNTER_MAX / MEN_Z069_TIMER_FREQ, | |
107 | }; | |
108 | ||
109 | static int men_z069_probe(struct mcb_device *dev, | |
110 | const struct mcb_device_id *id) | |
111 | { | |
112 | struct men_z069_drv *drv; | |
113 | struct resource *mem; | |
114 | ||
115 | drv = devm_kzalloc(&dev->dev, sizeof(struct men_z069_drv), GFP_KERNEL); | |
116 | if (!drv) | |
117 | return -ENOMEM; | |
118 | ||
119 | mem = mcb_request_mem(dev, "z069-wdt"); | |
120 | if (IS_ERR(mem)) | |
121 | return PTR_ERR(mem); | |
122 | ||
123 | drv->base = devm_ioremap(&dev->dev, mem->start, resource_size(mem)); | |
124 | if (drv->base == NULL) | |
125 | goto release_mem; | |
126 | ||
127 | drv->mem = mem; | |
128 | ||
129 | drv->wdt = men_z069_wdt; | |
130 | watchdog_init_timeout(&drv->wdt, 0, &dev->dev); | |
131 | watchdog_set_nowayout(&drv->wdt, nowayout); | |
132 | watchdog_set_drvdata(&drv->wdt, drv); | |
133 | drv->wdt.parent = &dev->dev; | |
134 | mcb_set_drvdata(dev, drv); | |
135 | ||
136 | return watchdog_register_device(&men_z069_wdt); | |
137 | ||
138 | release_mem: | |
139 | mcb_release_mem(mem); | |
140 | return -ENOMEM; | |
141 | } | |
142 | ||
143 | static void men_z069_remove(struct mcb_device *dev) | |
144 | { | |
145 | struct men_z069_drv *drv = mcb_get_drvdata(dev); | |
146 | ||
147 | watchdog_unregister_device(&drv->wdt); | |
148 | mcb_release_mem(drv->mem); | |
149 | } | |
150 | ||
151 | static const struct mcb_device_id men_z069_ids[] = { | |
152 | { .device = 0x45 }, | |
153 | { } | |
154 | }; | |
155 | MODULE_DEVICE_TABLE(mcb, men_z069_ids); | |
156 | ||
157 | static struct mcb_driver men_z069_driver = { | |
158 | .driver = { | |
159 | .name = "z069-wdt", | |
160 | .owner = THIS_MODULE, | |
161 | }, | |
162 | .probe = men_z069_probe, | |
163 | .remove = men_z069_remove, | |
164 | .id_table = men_z069_ids, | |
165 | }; | |
166 | module_mcb_driver(men_z069_driver); | |
167 | ||
168 | MODULE_AUTHOR("Johannes Thumshirn <jth@kernel.org>"); | |
169 | MODULE_LICENSE("GPL v2"); | |
170 | MODULE_ALIAS("mcb:16z069"); | |
891e6036 | 171 | MODULE_IMPORT_NS(MCB); |