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66aaa7a5 MZ |
1 | /* |
2 | * drivers/char/watchdog/max63xx_wdt.c | |
3 | * | |
4 | * Driver for max63{69,70,71,72,73,74} watchdog timers | |
5 | * | |
6 | * Copyright (C) 2009 Marc Zyngier <maz@misterjones.org> | |
7 | * | |
8 | * This file is licensed under the terms of the GNU General Public | |
9 | * License version 2. This program is licensed "as is" without any | |
10 | * warranty of any kind, whether express or implied. | |
11 | * | |
12 | * This driver assumes the watchdog pins are memory mapped (as it is | |
13 | * the case for the Arcom Zeus). Should it be connected over GPIOs or | |
14 | * another interface, some abstraction will have to be introduced. | |
15 | */ | |
16 | ||
4c271bb6 | 17 | #include <linux/err.h> |
66aaa7a5 MZ |
18 | #include <linux/module.h> |
19 | #include <linux/moduleparam.h> | |
20 | #include <linux/types.h> | |
21 | #include <linux/kernel.h> | |
66aaa7a5 MZ |
22 | #include <linux/watchdog.h> |
23 | #include <linux/init.h> | |
24 | #include <linux/bitops.h> | |
25 | #include <linux/platform_device.h> | |
26 | #include <linux/spinlock.h> | |
66aaa7a5 | 27 | #include <linux/io.h> |
5a0e3ad6 | 28 | #include <linux/slab.h> |
66aaa7a5 MZ |
29 | |
30 | #define DEFAULT_HEARTBEAT 60 | |
31 | #define MAX_HEARTBEAT 60 | |
32 | ||
a0f36833 | 33 | static unsigned int heartbeat = DEFAULT_HEARTBEAT; |
86a1e189 | 34 | static bool nowayout = WATCHDOG_NOWAYOUT; |
66aaa7a5 MZ |
35 | |
36 | /* | |
37 | * Memory mapping: a single byte, 3 first lower bits to select bit 3 | |
38 | * to ping the watchdog. | |
39 | */ | |
40 | #define MAX6369_WDSET (7 << 0) | |
5f3b2756 | 41 | #define MAX6369_WDI (1 << 3) |
66aaa7a5 MZ |
42 | |
43 | static DEFINE_SPINLOCK(io_lock); | |
44 | ||
66aaa7a5 | 45 | static int nodelay; |
66aaa7a5 | 46 | static void __iomem *wdt_base; |
66aaa7a5 MZ |
47 | |
48 | /* | |
49 | * The timeout values used are actually the absolute minimum the chip | |
50 | * offers. Typical values on my board are slightly over twice as long | |
51 | * (10s setting ends up with a 25s timeout), and can be up to 3 times | |
52 | * the nominal setting (according to the datasheet). So please take | |
53 | * these values with a grain of salt. Same goes for the initial delay | |
54 | * "feature". Only max6373/74 have a few settings without this initial | |
55 | * delay (selected with the "nodelay" parameter). | |
56 | * | |
57 | * I also decided to remove from the tables any timeout smaller than a | |
58 | * second, as it looked completly overkill... | |
59 | */ | |
60 | ||
61 | /* Timeouts in second */ | |
62 | struct max63xx_timeout { | |
63 | u8 wdset; | |
64 | u8 tdelay; | |
65 | u8 twd; | |
66 | }; | |
67 | ||
68 | static struct max63xx_timeout max6369_table[] = { | |
69 | { 5, 1, 1 }, | |
70 | { 6, 10, 10 }, | |
71 | { 7, 60, 60 }, | |
72 | { }, | |
73 | }; | |
74 | ||
75 | static struct max63xx_timeout max6371_table[] = { | |
76 | { 6, 60, 3 }, | |
77 | { 7, 60, 60 }, | |
78 | { }, | |
79 | }; | |
80 | ||
81 | static struct max63xx_timeout max6373_table[] = { | |
82 | { 2, 60, 1 }, | |
83 | { 5, 0, 1 }, | |
84 | { 1, 3, 3 }, | |
85 | { 7, 60, 10 }, | |
86 | { 6, 0, 10 }, | |
87 | { }, | |
88 | }; | |
89 | ||
90 | static struct max63xx_timeout *current_timeout; | |
91 | ||
92 | static struct max63xx_timeout * | |
93 | max63xx_select_timeout(struct max63xx_timeout *table, int value) | |
94 | { | |
95 | while (table->twd) { | |
96 | if (value <= table->twd) { | |
97 | if (nodelay && table->tdelay == 0) | |
98 | return table; | |
99 | ||
100 | if (!nodelay) | |
101 | return table; | |
102 | } | |
103 | ||
104 | table++; | |
105 | } | |
106 | ||
107 | return NULL; | |
108 | } | |
109 | ||
a0f36833 | 110 | static int max63xx_wdt_ping(struct watchdog_device *wdd) |
66aaa7a5 MZ |
111 | { |
112 | u8 val; | |
113 | ||
114 | spin_lock(&io_lock); | |
115 | ||
116 | val = __raw_readb(wdt_base); | |
117 | ||
118 | __raw_writeb(val | MAX6369_WDI, wdt_base); | |
119 | __raw_writeb(val & ~MAX6369_WDI, wdt_base); | |
120 | ||
121 | spin_unlock(&io_lock); | |
a0f36833 | 122 | return 0; |
66aaa7a5 MZ |
123 | } |
124 | ||
a0f36833 | 125 | static int max63xx_wdt_start(struct watchdog_device *wdd) |
66aaa7a5 | 126 | { |
a0f36833 | 127 | struct max63xx_timeout *entry = watchdog_get_drvdata(wdd); |
66aaa7a5 MZ |
128 | u8 val; |
129 | ||
66aaa7a5 MZ |
130 | spin_lock(&io_lock); |
131 | ||
132 | val = __raw_readb(wdt_base); | |
133 | val &= ~MAX6369_WDSET; | |
134 | val |= entry->wdset; | |
135 | __raw_writeb(val, wdt_base); | |
136 | ||
137 | spin_unlock(&io_lock); | |
138 | ||
139 | /* check for a edge triggered startup */ | |
140 | if (entry->tdelay == 0) | |
a0f36833 AL |
141 | max63xx_wdt_ping(wdd); |
142 | return 0; | |
66aaa7a5 MZ |
143 | } |
144 | ||
a0f36833 | 145 | static int max63xx_wdt_stop(struct watchdog_device *wdd) |
66aaa7a5 | 146 | { |
b1183e06 MZ |
147 | u8 val; |
148 | ||
66aaa7a5 MZ |
149 | spin_lock(&io_lock); |
150 | ||
b1183e06 MZ |
151 | val = __raw_readb(wdt_base); |
152 | val &= ~MAX6369_WDSET; | |
153 | val |= 3; | |
154 | __raw_writeb(val, wdt_base); | |
66aaa7a5 MZ |
155 | |
156 | spin_unlock(&io_lock); | |
a0f36833 | 157 | return 0; |
66aaa7a5 MZ |
158 | } |
159 | ||
a0f36833 AL |
160 | static const struct watchdog_info max63xx_wdt_info = { |
161 | .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, | |
66aaa7a5 MZ |
162 | .identity = "max63xx Watchdog", |
163 | }; | |
164 | ||
a0f36833 AL |
165 | static const struct watchdog_ops max63xx_wdt_ops = { |
166 | .owner = THIS_MODULE, | |
167 | .start = max63xx_wdt_start, | |
168 | .stop = max63xx_wdt_stop, | |
169 | .ping = max63xx_wdt_ping, | |
66aaa7a5 MZ |
170 | }; |
171 | ||
a0f36833 AL |
172 | static struct watchdog_device max63xx_wdt_dev = { |
173 | .info = &max63xx_wdt_info, | |
174 | .ops = &max63xx_wdt_ops, | |
66aaa7a5 MZ |
175 | }; |
176 | ||
2d991a16 | 177 | static int max63xx_wdt_probe(struct platform_device *pdev) |
66aaa7a5 | 178 | { |
a0f36833 | 179 | struct resource *wdt_mem; |
66aaa7a5 MZ |
180 | struct max63xx_timeout *table; |
181 | ||
182 | table = (struct max63xx_timeout *)pdev->id_entry->driver_data; | |
183 | ||
184 | if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT) | |
185 | heartbeat = DEFAULT_HEARTBEAT; | |
186 | ||
a0f36833 | 187 | dev_info(&pdev->dev, "requesting %ds heartbeat\n", heartbeat); |
66aaa7a5 MZ |
188 | current_timeout = max63xx_select_timeout(table, heartbeat); |
189 | ||
190 | if (!current_timeout) { | |
a0f36833 | 191 | dev_err(&pdev->dev, "unable to satisfy heartbeat request\n"); |
66aaa7a5 MZ |
192 | return -EINVAL; |
193 | } | |
194 | ||
a0f36833 | 195 | dev_info(&pdev->dev, "using %ds heartbeat with %ds initial delay\n", |
66aaa7a5 MZ |
196 | current_timeout->twd, current_timeout->tdelay); |
197 | ||
198 | heartbeat = current_timeout->twd; | |
199 | ||
f712eacf | 200 | wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
4c271bb6 TR |
201 | wdt_base = devm_ioremap_resource(&pdev->dev, wdt_mem); |
202 | if (IS_ERR(wdt_base)) | |
203 | return PTR_ERR(wdt_base); | |
66aaa7a5 | 204 | |
a0f36833 AL |
205 | max63xx_wdt_dev.timeout = heartbeat; |
206 | watchdog_set_nowayout(&max63xx_wdt_dev, nowayout); | |
207 | watchdog_set_drvdata(&max63xx_wdt_dev, current_timeout); | |
66aaa7a5 | 208 | |
a0f36833 | 209 | return watchdog_register_device(&max63xx_wdt_dev); |
66aaa7a5 MZ |
210 | } |
211 | ||
4b12b896 | 212 | static int max63xx_wdt_remove(struct platform_device *pdev) |
66aaa7a5 | 213 | { |
a0f36833 | 214 | watchdog_unregister_device(&max63xx_wdt_dev); |
66aaa7a5 MZ |
215 | return 0; |
216 | } | |
217 | ||
218 | static struct platform_device_id max63xx_id_table[] = { | |
219 | { "max6369_wdt", (kernel_ulong_t)max6369_table, }, | |
220 | { "max6370_wdt", (kernel_ulong_t)max6369_table, }, | |
221 | { "max6371_wdt", (kernel_ulong_t)max6371_table, }, | |
222 | { "max6372_wdt", (kernel_ulong_t)max6371_table, }, | |
223 | { "max6373_wdt", (kernel_ulong_t)max6373_table, }, | |
224 | { "max6374_wdt", (kernel_ulong_t)max6373_table, }, | |
225 | { }, | |
226 | }; | |
227 | MODULE_DEVICE_TABLE(platform, max63xx_id_table); | |
228 | ||
229 | static struct platform_driver max63xx_wdt_driver = { | |
230 | .probe = max63xx_wdt_probe, | |
82268714 | 231 | .remove = max63xx_wdt_remove, |
66aaa7a5 MZ |
232 | .id_table = max63xx_id_table, |
233 | .driver = { | |
234 | .name = "max63xx_wdt", | |
235 | .owner = THIS_MODULE, | |
236 | }, | |
237 | }; | |
238 | ||
b8ec6118 | 239 | module_platform_driver(max63xx_wdt_driver); |
66aaa7a5 MZ |
240 | |
241 | MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>"); | |
242 | MODULE_DESCRIPTION("max63xx Watchdog Driver"); | |
243 | ||
244 | module_param(heartbeat, int, 0); | |
245 | MODULE_PARM_DESC(heartbeat, | |
246 | "Watchdog heartbeat period in seconds from 1 to " | |
247 | __MODULE_STRING(MAX_HEARTBEAT) ", default " | |
248 | __MODULE_STRING(DEFAULT_HEARTBEAT)); | |
249 | ||
86a1e189 | 250 | module_param(nowayout, bool, 0); |
66aaa7a5 MZ |
251 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
252 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
253 | ||
254 | module_param(nodelay, int, 0); | |
255 | MODULE_PARM_DESC(nodelay, | |
256 | "Force selection of a timeout setting without initial delay " | |
257 | "(max6373/74 only, default=0)"); | |
258 | ||
259 | MODULE_LICENSE("GPL"); |