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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>
27#include <linux/io.h>
28#include <linux/kernel.h>
29#include <linux/types.h>
30#include <linux/watchdog.h>
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
63static unsigned int timeout = DEFAULT_TIME;
64module_param(timeout, uint, 0);
65MODULE_PARM_DESC(timeout,
66 "Default Watchdog timer setting ("
67 __MODULE_STRING(DEFAULT_TIME) "s)."
68 "The range is from 1 to 600");
69
70static bool nowayout = WATCHDOG_NOWAYOUT;
71module_param(nowayout, bool, 0);
72MODULE_PARM_DESC(nowayout,
73 "Watchdog cannot be stopped once started (default="
74 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
75
76static u8 resetmode = 0x10;
77module_param(resetmode, byte, 0);
78MODULE_PARM_DESC(resetmode,
79 "Resetmode bits: 0x08 warm reset (cold reset otherwise), "
80 "0x10 reset enable, 0x20 disable toggle GPIO[4] (default=0x10)");
81
82static 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 */
95static 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
101static 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
110static 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
147static 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
159static 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
172static 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
179static 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
187static 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
196static 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
215static int ie6xx_wdt_dbg_open(struct inode *inode, struct file *file)
216{
217 return single_open(file, ie6xx_wdt_dbg_show, NULL);
218}
219
220static 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
227static void ie6xx_wdt_debugfs_init(void)
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
234static void ie6xx_wdt_debugfs_exit(void)
235{
236 debugfs_remove(ie6xx_wdt_data.debugfs);
237}
238
239#else
240static void ie6xx_wdt_debugfs_init(void)
241{
242}
243
244static void ie6xx_wdt_debugfs_exit(void)
245{
246}
247#endif
248
249static int ie6xx_wdt_probe(struct platform_device *pdev)
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)) {
260 dev_err(&pdev->dev, "Watchdog region 0x%llx already in use!\n",
261 (u64)res->start);
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);
270 ie6xx_wdt_dev.parent = &pdev->dev;
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
291misc_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
298static int ie6xx_wdt_remove(struct platform_device *pdev)
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
312static struct platform_driver ie6xx_wdt_driver = {
313 .probe = ie6xx_wdt_probe,
314 .remove = ie6xx_wdt_remove,
315 .driver = {
316 .name = DRIVER_NAME,
317 },
318};
319
320static 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
335static void __exit ie6xx_wdt_exit(void)
336{
337 platform_driver_unregister(&ie6xx_wdt_driver);
338}
339
340late_initcall(ie6xx_wdt_init);
341module_exit(ie6xx_wdt_exit);
342
343MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
344MODULE_DESCRIPTION("Intel Atom E6xx Watchdog Device Driver");
345MODULE_LICENSE("GPL");
346MODULE_ALIAS("platform:" DRIVER_NAME);