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101ce87b AS |
1 | /* |
2 | * Intel Atom E6xx Watchdog driver | |
3 | * | |
4 | * Copyright (C) 2011 Alexander Stein | |
5 | * <alexander.stein@systec-electronic.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of version 2 of the GNU General | |
9 | * Public License as published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope that it will be | |
12 | * useful, but WITHOUT ANY WARRANTY; without even the implied | |
13 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR | |
14 | * PURPOSE. See the GNU General Public License for more details. | |
15 | * You should have received a copy of the GNU General Public | |
16 | * License along with this program; if not, write to the Free | |
17 | * Software Foundation, Inc., 59 Temple Place - Suite 330, | |
18 | * Boston, MA 02111-1307, USA. | |
19 | * The full GNU General Public License is included in this | |
20 | * distribution in the file called COPYING. | |
21 | * | |
22 | */ | |
23 | ||
24 | #include <linux/module.h> | |
25 | #include <linux/moduleparam.h> | |
26 | #include <linux/platform_device.h> | |
491d9e2a | 27 | #include <linux/io.h> |
101ce87b AS |
28 | #include <linux/kernel.h> |
29 | #include <linux/types.h> | |
30 | #include <linux/watchdog.h> | |
101ce87b AS |
31 | #include <linux/seq_file.h> |
32 | #include <linux/debugfs.h> | |
33 | #include <linux/uaccess.h> | |
34 | #include <linux/spinlock.h> | |
35 | ||
36 | #define DRIVER_NAME "ie6xx_wdt" | |
37 | ||
38 | #define PV1 0x00 | |
39 | #define PV2 0x04 | |
40 | ||
41 | #define RR0 0x0c | |
42 | #define RR1 0x0d | |
43 | #define WDT_RELOAD 0x01 | |
44 | #define WDT_TOUT 0x02 | |
45 | ||
46 | #define WDTCR 0x10 | |
47 | #define WDT_PRE_SEL 0x04 | |
48 | #define WDT_RESET_SEL 0x08 | |
49 | #define WDT_RESET_EN 0x10 | |
50 | #define WDT_TOUT_EN 0x20 | |
51 | ||
52 | #define DCR 0x14 | |
53 | ||
54 | #define WDTLR 0x18 | |
55 | #define WDT_LOCK 0x01 | |
56 | #define WDT_ENABLE 0x02 | |
57 | #define WDT_TOUT_CNF 0x03 | |
58 | ||
59 | #define MIN_TIME 1 | |
60 | #define MAX_TIME (10 * 60) /* 10 minutes */ | |
61 | #define DEFAULT_TIME 60 | |
62 | ||
63 | static unsigned int timeout = DEFAULT_TIME; | |
64 | module_param(timeout, uint, 0); | |
65 | MODULE_PARM_DESC(timeout, | |
66 | "Default Watchdog timer setting (" | |
67 | __MODULE_STRING(DEFAULT_TIME) "s)." | |
68 | "The range is from 1 to 600"); | |
69 | ||
70 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
71 | module_param(nowayout, bool, 0); | |
72 | MODULE_PARM_DESC(nowayout, | |
73 | "Watchdog cannot be stopped once started (default=" | |
74 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
75 | ||
76 | static u8 resetmode = 0x10; | |
77 | module_param(resetmode, byte, 0); | |
78 | MODULE_PARM_DESC(resetmode, | |
79 | "Resetmode bits: 0x08 warm reset (cold reset otherwise), " | |
80 | "0x10 reset enable, 0x20 disable toggle GPIO[4] (default=0x10)"); | |
81 | ||
82 | static struct { | |
83 | unsigned short sch_wdtba; | |
84 | struct spinlock unlock_sequence; | |
85 | #ifdef CONFIG_DEBUG_FS | |
86 | struct dentry *debugfs; | |
87 | #endif | |
88 | } ie6xx_wdt_data; | |
89 | ||
90 | /* | |
91 | * This is needed to write to preload and reload registers | |
92 | * struct ie6xx_wdt_data.unlock_sequence must be used | |
93 | * to prevent sequence interrupts | |
94 | */ | |
95 | static void ie6xx_wdt_unlock_registers(void) | |
96 | { | |
97 | outb(0x80, ie6xx_wdt_data.sch_wdtba + RR0); | |
98 | outb(0x86, ie6xx_wdt_data.sch_wdtba + RR0); | |
99 | } | |
100 | ||
101 | static int ie6xx_wdt_ping(struct watchdog_device *wdd) | |
102 | { | |
103 | spin_lock(&ie6xx_wdt_data.unlock_sequence); | |
104 | ie6xx_wdt_unlock_registers(); | |
105 | outb(WDT_RELOAD, ie6xx_wdt_data.sch_wdtba + RR1); | |
106 | spin_unlock(&ie6xx_wdt_data.unlock_sequence); | |
107 | return 0; | |
108 | } | |
109 | ||
110 | static int ie6xx_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t) | |
111 | { | |
112 | u32 preload; | |
113 | u64 clock; | |
114 | u8 wdtcr; | |
115 | ||
116 | /* Watchdog clock is PCI Clock (33MHz) */ | |
117 | clock = 33000000; | |
118 | /* and the preload value is loaded into [34:15] of the down counter */ | |
119 | preload = (t * clock) >> 15; | |
120 | /* | |
121 | * Manual states preload must be one less. | |
122 | * Does not wrap as t is at least 1 | |
123 | */ | |
124 | preload -= 1; | |
125 | ||
126 | spin_lock(&ie6xx_wdt_data.unlock_sequence); | |
127 | ||
128 | /* Set ResetMode & Enable prescaler for range 10ms to 10 min */ | |
129 | wdtcr = resetmode & 0x38; | |
130 | outb(wdtcr, ie6xx_wdt_data.sch_wdtba + WDTCR); | |
131 | ||
132 | ie6xx_wdt_unlock_registers(); | |
133 | outl(0, ie6xx_wdt_data.sch_wdtba + PV1); | |
134 | ||
135 | ie6xx_wdt_unlock_registers(); | |
136 | outl(preload, ie6xx_wdt_data.sch_wdtba + PV2); | |
137 | ||
138 | ie6xx_wdt_unlock_registers(); | |
139 | outb(WDT_RELOAD | WDT_TOUT, ie6xx_wdt_data.sch_wdtba + RR1); | |
140 | ||
141 | spin_unlock(&ie6xx_wdt_data.unlock_sequence); | |
142 | ||
143 | wdd->timeout = t; | |
144 | return 0; | |
145 | } | |
146 | ||
147 | static int ie6xx_wdt_start(struct watchdog_device *wdd) | |
148 | { | |
149 | ie6xx_wdt_set_timeout(wdd, wdd->timeout); | |
150 | ||
151 | /* Enable the watchdog timer */ | |
152 | spin_lock(&ie6xx_wdt_data.unlock_sequence); | |
153 | outb(WDT_ENABLE, ie6xx_wdt_data.sch_wdtba + WDTLR); | |
154 | spin_unlock(&ie6xx_wdt_data.unlock_sequence); | |
155 | ||
156 | return 0; | |
157 | } | |
158 | ||
159 | static int ie6xx_wdt_stop(struct watchdog_device *wdd) | |
160 | { | |
161 | if (inb(ie6xx_wdt_data.sch_wdtba + WDTLR) & WDT_LOCK) | |
162 | return -1; | |
163 | ||
164 | /* Disable the watchdog timer */ | |
165 | spin_lock(&ie6xx_wdt_data.unlock_sequence); | |
166 | outb(0, ie6xx_wdt_data.sch_wdtba + WDTLR); | |
167 | spin_unlock(&ie6xx_wdt_data.unlock_sequence); | |
168 | ||
169 | return 0; | |
170 | } | |
171 | ||
172 | static const struct watchdog_info ie6xx_wdt_info = { | |
173 | .identity = "Intel Atom E6xx Watchdog", | |
174 | .options = WDIOF_SETTIMEOUT | | |
175 | WDIOF_MAGICCLOSE | | |
176 | WDIOF_KEEPALIVEPING, | |
177 | }; | |
178 | ||
179 | static const struct watchdog_ops ie6xx_wdt_ops = { | |
180 | .owner = THIS_MODULE, | |
181 | .start = ie6xx_wdt_start, | |
182 | .stop = ie6xx_wdt_stop, | |
183 | .ping = ie6xx_wdt_ping, | |
184 | .set_timeout = ie6xx_wdt_set_timeout, | |
185 | }; | |
186 | ||
187 | static struct watchdog_device ie6xx_wdt_dev = { | |
188 | .info = &ie6xx_wdt_info, | |
189 | .ops = &ie6xx_wdt_ops, | |
190 | .min_timeout = MIN_TIME, | |
191 | .max_timeout = MAX_TIME, | |
192 | }; | |
193 | ||
194 | #ifdef CONFIG_DEBUG_FS | |
195 | ||
196 | static int ie6xx_wdt_dbg_show(struct seq_file *s, void *unused) | |
197 | { | |
198 | seq_printf(s, "PV1 = 0x%08x\n", | |
199 | inl(ie6xx_wdt_data.sch_wdtba + PV1)); | |
200 | seq_printf(s, "PV2 = 0x%08x\n", | |
201 | inl(ie6xx_wdt_data.sch_wdtba + PV2)); | |
202 | seq_printf(s, "RR = 0x%08x\n", | |
203 | inw(ie6xx_wdt_data.sch_wdtba + RR0)); | |
204 | seq_printf(s, "WDTCR = 0x%08x\n", | |
205 | inw(ie6xx_wdt_data.sch_wdtba + WDTCR)); | |
206 | seq_printf(s, "DCR = 0x%08x\n", | |
207 | inl(ie6xx_wdt_data.sch_wdtba + DCR)); | |
208 | seq_printf(s, "WDTLR = 0x%08x\n", | |
209 | inw(ie6xx_wdt_data.sch_wdtba + WDTLR)); | |
210 | ||
211 | seq_printf(s, "\n"); | |
212 | return 0; | |
213 | } | |
214 | ||
215 | static int ie6xx_wdt_dbg_open(struct inode *inode, struct file *file) | |
216 | { | |
217 | return single_open(file, ie6xx_wdt_dbg_show, NULL); | |
218 | } | |
219 | ||
220 | static const struct file_operations ie6xx_wdt_dbg_operations = { | |
221 | .open = ie6xx_wdt_dbg_open, | |
222 | .read = seq_read, | |
223 | .llseek = seq_lseek, | |
224 | .release = single_release, | |
225 | }; | |
226 | ||
2d991a16 | 227 | static void ie6xx_wdt_debugfs_init(void) |
101ce87b AS |
228 | { |
229 | /* /sys/kernel/debug/ie6xx_wdt */ | |
230 | ie6xx_wdt_data.debugfs = debugfs_create_file("ie6xx_wdt", | |
231 | S_IFREG | S_IRUGO, NULL, NULL, &ie6xx_wdt_dbg_operations); | |
232 | } | |
233 | ||
0402450f | 234 | static void ie6xx_wdt_debugfs_exit(void) |
101ce87b AS |
235 | { |
236 | debugfs_remove(ie6xx_wdt_data.debugfs); | |
237 | } | |
238 | ||
239 | #else | |
2d991a16 | 240 | static void ie6xx_wdt_debugfs_init(void) |
101ce87b AS |
241 | { |
242 | } | |
243 | ||
0402450f | 244 | static void ie6xx_wdt_debugfs_exit(void) |
101ce87b AS |
245 | { |
246 | } | |
247 | #endif | |
248 | ||
2d991a16 | 249 | static int ie6xx_wdt_probe(struct platform_device *pdev) |
101ce87b AS |
250 | { |
251 | struct resource *res; | |
252 | u8 wdtlr; | |
253 | int ret; | |
254 | ||
255 | res = platform_get_resource(pdev, IORESOURCE_IO, 0); | |
256 | if (!res) | |
257 | return -ENODEV; | |
258 | ||
259 | if (!request_region(res->start, resource_size(res), pdev->name)) { | |
744f6f4d RD |
260 | dev_err(&pdev->dev, "Watchdog region 0x%llx already in use!\n", |
261 | (u64)res->start); | |
101ce87b AS |
262 | return -EBUSY; |
263 | } | |
264 | ||
265 | ie6xx_wdt_data.sch_wdtba = res->start; | |
266 | dev_dbg(&pdev->dev, "WDT = 0x%X\n", ie6xx_wdt_data.sch_wdtba); | |
267 | ||
268 | ie6xx_wdt_dev.timeout = timeout; | |
269 | watchdog_set_nowayout(&ie6xx_wdt_dev, nowayout); | |
6551881c | 270 | ie6xx_wdt_dev.parent = &pdev->dev; |
101ce87b AS |
271 | |
272 | spin_lock_init(&ie6xx_wdt_data.unlock_sequence); | |
273 | ||
274 | wdtlr = inb(ie6xx_wdt_data.sch_wdtba + WDTLR); | |
275 | if (wdtlr & WDT_LOCK) | |
276 | dev_warn(&pdev->dev, | |
277 | "Watchdog Timer is Locked (Reg=0x%x)\n", wdtlr); | |
278 | ||
279 | ie6xx_wdt_debugfs_init(); | |
280 | ||
281 | ret = watchdog_register_device(&ie6xx_wdt_dev); | |
282 | if (ret) { | |
283 | dev_err(&pdev->dev, | |
284 | "Watchdog timer: cannot register device (err =%d)\n", | |
285 | ret); | |
286 | goto misc_register_error; | |
287 | } | |
288 | ||
289 | return 0; | |
290 | ||
291 | misc_register_error: | |
292 | ie6xx_wdt_debugfs_exit(); | |
293 | release_region(res->start, resource_size(res)); | |
294 | ie6xx_wdt_data.sch_wdtba = 0; | |
295 | return ret; | |
296 | } | |
297 | ||
4b12b896 | 298 | static int ie6xx_wdt_remove(struct platform_device *pdev) |
101ce87b AS |
299 | { |
300 | struct resource *res; | |
301 | ||
302 | res = platform_get_resource(pdev, IORESOURCE_IO, 0); | |
303 | ie6xx_wdt_stop(NULL); | |
304 | watchdog_unregister_device(&ie6xx_wdt_dev); | |
305 | ie6xx_wdt_debugfs_exit(); | |
306 | release_region(res->start, resource_size(res)); | |
307 | ie6xx_wdt_data.sch_wdtba = 0; | |
308 | ||
309 | return 0; | |
310 | } | |
311 | ||
312 | static struct platform_driver ie6xx_wdt_driver = { | |
313 | .probe = ie6xx_wdt_probe, | |
82268714 | 314 | .remove = ie6xx_wdt_remove, |
101ce87b AS |
315 | .driver = { |
316 | .name = DRIVER_NAME, | |
101ce87b AS |
317 | }, |
318 | }; | |
319 | ||
320 | static int __init ie6xx_wdt_init(void) | |
321 | { | |
322 | /* Check boot parameters to verify that their initial values */ | |
323 | /* are in range. */ | |
324 | if ((timeout < MIN_TIME) || | |
325 | (timeout > MAX_TIME)) { | |
326 | pr_err("Watchdog timer: value of timeout %d (dec) " | |
327 | "is out of range from %d to %d (dec)\n", | |
328 | timeout, MIN_TIME, MAX_TIME); | |
329 | return -EINVAL; | |
330 | } | |
331 | ||
332 | return platform_driver_register(&ie6xx_wdt_driver); | |
333 | } | |
334 | ||
335 | static void __exit ie6xx_wdt_exit(void) | |
336 | { | |
337 | platform_driver_unregister(&ie6xx_wdt_driver); | |
338 | } | |
339 | ||
340 | late_initcall(ie6xx_wdt_init); | |
341 | module_exit(ie6xx_wdt_exit); | |
342 | ||
343 | MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>"); | |
344 | MODULE_DESCRIPTION("Intel Atom E6xx Watchdog Device Driver"); | |
345 | MODULE_LICENSE("GPL"); | |
101ce87b | 346 | MODULE_ALIAS("platform:" DRIVER_NAME); |