2 * Intel Atom E6xx Watchdog driver
4 * Copyright (C) 2011 Alexander Stein
5 * <alexander.stein@systec-electronic.com>
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.
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.
24 #include <linux/module.h>
25 #include <linux/moduleparam.h>
26 #include <linux/platform_device.h>
28 #include <linux/kernel.h>
29 #include <linux/types.h>
30 #include <linux/watchdog.h>
31 #include <linux/miscdevice.h>
32 #include <linux/seq_file.h>
33 #include <linux/debugfs.h>
34 #include <linux/uaccess.h>
35 #include <linux/spinlock.h>
37 #define DRIVER_NAME "ie6xx_wdt"
44 #define WDT_RELOAD 0x01
48 #define WDT_PRE_SEL 0x04
49 #define WDT_RESET_SEL 0x08
50 #define WDT_RESET_EN 0x10
51 #define WDT_TOUT_EN 0x20
57 #define WDT_ENABLE 0x02
58 #define WDT_TOUT_CNF 0x03
61 #define MAX_TIME (10 * 60) /* 10 minutes */
62 #define DEFAULT_TIME 60
64 static unsigned int timeout
= DEFAULT_TIME
;
65 module_param(timeout
, uint
, 0);
66 MODULE_PARM_DESC(timeout
,
67 "Default Watchdog timer setting ("
68 __MODULE_STRING(DEFAULT_TIME
) "s)."
69 "The range is from 1 to 600");
71 static bool nowayout
= WATCHDOG_NOWAYOUT
;
72 module_param(nowayout
, bool, 0);
73 MODULE_PARM_DESC(nowayout
,
74 "Watchdog cannot be stopped once started (default="
75 __MODULE_STRING(WATCHDOG_NOWAYOUT
) ")");
77 static u8 resetmode
= 0x10;
78 module_param(resetmode
, byte
, 0);
79 MODULE_PARM_DESC(resetmode
,
80 "Resetmode bits: 0x08 warm reset (cold reset otherwise), "
81 "0x10 reset enable, 0x20 disable toggle GPIO[4] (default=0x10)");
84 unsigned short sch_wdtba
;
85 struct spinlock unlock_sequence
;
86 #ifdef CONFIG_DEBUG_FS
87 struct dentry
*debugfs
;
92 * This is needed to write to preload and reload registers
93 * struct ie6xx_wdt_data.unlock_sequence must be used
94 * to prevent sequence interrupts
96 static void ie6xx_wdt_unlock_registers(void)
98 outb(0x80, ie6xx_wdt_data
.sch_wdtba
+ RR0
);
99 outb(0x86, ie6xx_wdt_data
.sch_wdtba
+ RR0
);
102 static int ie6xx_wdt_ping(struct watchdog_device
*wdd
)
104 spin_lock(&ie6xx_wdt_data
.unlock_sequence
);
105 ie6xx_wdt_unlock_registers();
106 outb(WDT_RELOAD
, ie6xx_wdt_data
.sch_wdtba
+ RR1
);
107 spin_unlock(&ie6xx_wdt_data
.unlock_sequence
);
111 static int ie6xx_wdt_set_timeout(struct watchdog_device
*wdd
, unsigned int t
)
117 /* Watchdog clock is PCI Clock (33MHz) */
119 /* and the preload value is loaded into [34:15] of the down counter */
120 preload
= (t
* clock
) >> 15;
122 * Manual states preload must be one less.
123 * Does not wrap as t is at least 1
127 spin_lock(&ie6xx_wdt_data
.unlock_sequence
);
129 /* Set ResetMode & Enable prescaler for range 10ms to 10 min */
130 wdtcr
= resetmode
& 0x38;
131 outb(wdtcr
, ie6xx_wdt_data
.sch_wdtba
+ WDTCR
);
133 ie6xx_wdt_unlock_registers();
134 outl(0, ie6xx_wdt_data
.sch_wdtba
+ PV1
);
136 ie6xx_wdt_unlock_registers();
137 outl(preload
, ie6xx_wdt_data
.sch_wdtba
+ PV2
);
139 ie6xx_wdt_unlock_registers();
140 outb(WDT_RELOAD
| WDT_TOUT
, ie6xx_wdt_data
.sch_wdtba
+ RR1
);
142 spin_unlock(&ie6xx_wdt_data
.unlock_sequence
);
148 static int ie6xx_wdt_start(struct watchdog_device
*wdd
)
150 ie6xx_wdt_set_timeout(wdd
, wdd
->timeout
);
152 /* Enable the watchdog timer */
153 spin_lock(&ie6xx_wdt_data
.unlock_sequence
);
154 outb(WDT_ENABLE
, ie6xx_wdt_data
.sch_wdtba
+ WDTLR
);
155 spin_unlock(&ie6xx_wdt_data
.unlock_sequence
);
160 static int ie6xx_wdt_stop(struct watchdog_device
*wdd
)
162 if (inb(ie6xx_wdt_data
.sch_wdtba
+ WDTLR
) & WDT_LOCK
)
165 /* Disable the watchdog timer */
166 spin_lock(&ie6xx_wdt_data
.unlock_sequence
);
167 outb(0, ie6xx_wdt_data
.sch_wdtba
+ WDTLR
);
168 spin_unlock(&ie6xx_wdt_data
.unlock_sequence
);
173 static const struct watchdog_info ie6xx_wdt_info
= {
174 .identity
= "Intel Atom E6xx Watchdog",
175 .options
= WDIOF_SETTIMEOUT
|
180 static const struct watchdog_ops ie6xx_wdt_ops
= {
181 .owner
= THIS_MODULE
,
182 .start
= ie6xx_wdt_start
,
183 .stop
= ie6xx_wdt_stop
,
184 .ping
= ie6xx_wdt_ping
,
185 .set_timeout
= ie6xx_wdt_set_timeout
,
188 static struct watchdog_device ie6xx_wdt_dev
= {
189 .info
= &ie6xx_wdt_info
,
190 .ops
= &ie6xx_wdt_ops
,
191 .min_timeout
= MIN_TIME
,
192 .max_timeout
= MAX_TIME
,
195 #ifdef CONFIG_DEBUG_FS
197 static int ie6xx_wdt_dbg_show(struct seq_file
*s
, void *unused
)
199 seq_printf(s
, "PV1 = 0x%08x\n",
200 inl(ie6xx_wdt_data
.sch_wdtba
+ PV1
));
201 seq_printf(s
, "PV2 = 0x%08x\n",
202 inl(ie6xx_wdt_data
.sch_wdtba
+ PV2
));
203 seq_printf(s
, "RR = 0x%08x\n",
204 inw(ie6xx_wdt_data
.sch_wdtba
+ RR0
));
205 seq_printf(s
, "WDTCR = 0x%08x\n",
206 inw(ie6xx_wdt_data
.sch_wdtba
+ WDTCR
));
207 seq_printf(s
, "DCR = 0x%08x\n",
208 inl(ie6xx_wdt_data
.sch_wdtba
+ DCR
));
209 seq_printf(s
, "WDTLR = 0x%08x\n",
210 inw(ie6xx_wdt_data
.sch_wdtba
+ WDTLR
));
216 static int ie6xx_wdt_dbg_open(struct inode
*inode
, struct file
*file
)
218 return single_open(file
, ie6xx_wdt_dbg_show
, NULL
);
221 static const struct file_operations ie6xx_wdt_dbg_operations
= {
222 .open
= ie6xx_wdt_dbg_open
,
225 .release
= single_release
,
228 static void ie6xx_wdt_debugfs_init(void)
230 /* /sys/kernel/debug/ie6xx_wdt */
231 ie6xx_wdt_data
.debugfs
= debugfs_create_file("ie6xx_wdt",
232 S_IFREG
| S_IRUGO
, NULL
, NULL
, &ie6xx_wdt_dbg_operations
);
235 static void ie6xx_wdt_debugfs_exit(void)
237 debugfs_remove(ie6xx_wdt_data
.debugfs
);
241 static void ie6xx_wdt_debugfs_init(void)
245 static void ie6xx_wdt_debugfs_exit(void)
250 static int ie6xx_wdt_probe(struct platform_device
*pdev
)
252 struct resource
*res
;
256 res
= platform_get_resource(pdev
, IORESOURCE_IO
, 0);
260 if (!request_region(res
->start
, resource_size(res
), pdev
->name
)) {
261 dev_err(&pdev
->dev
, "Watchdog region 0x%llx already in use!\n",
266 ie6xx_wdt_data
.sch_wdtba
= res
->start
;
267 dev_dbg(&pdev
->dev
, "WDT = 0x%X\n", ie6xx_wdt_data
.sch_wdtba
);
269 ie6xx_wdt_dev
.timeout
= timeout
;
270 watchdog_set_nowayout(&ie6xx_wdt_dev
, nowayout
);
272 spin_lock_init(&ie6xx_wdt_data
.unlock_sequence
);
274 wdtlr
= inb(ie6xx_wdt_data
.sch_wdtba
+ WDTLR
);
275 if (wdtlr
& WDT_LOCK
)
277 "Watchdog Timer is Locked (Reg=0x%x)\n", wdtlr
);
279 ie6xx_wdt_debugfs_init();
281 ret
= watchdog_register_device(&ie6xx_wdt_dev
);
284 "Watchdog timer: cannot register device (err =%d)\n",
286 goto misc_register_error
;
292 ie6xx_wdt_debugfs_exit();
293 release_region(res
->start
, resource_size(res
));
294 ie6xx_wdt_data
.sch_wdtba
= 0;
298 static int ie6xx_wdt_remove(struct platform_device
*pdev
)
300 struct resource
*res
;
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;
312 static struct platform_driver ie6xx_wdt_driver
= {
313 .probe
= ie6xx_wdt_probe
,
314 .remove
= ie6xx_wdt_remove
,
317 .owner
= THIS_MODULE
,
321 static int __init
ie6xx_wdt_init(void)
323 /* Check boot parameters to verify that their initial values */
325 if ((timeout
< MIN_TIME
) ||
326 (timeout
> MAX_TIME
)) {
327 pr_err("Watchdog timer: value of timeout %d (dec) "
328 "is out of range from %d to %d (dec)\n",
329 timeout
, MIN_TIME
, MAX_TIME
);
333 return platform_driver_register(&ie6xx_wdt_driver
);
336 static void __exit
ie6xx_wdt_exit(void)
338 platform_driver_unregister(&ie6xx_wdt_driver
);
341 late_initcall(ie6xx_wdt_init
);
342 module_exit(ie6xx_wdt_exit
);
344 MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
345 MODULE_DESCRIPTION("Intel Atom E6xx Watchdog Device Driver");
346 MODULE_LICENSE("GPL");
347 MODULE_ALIAS("platform:" DRIVER_NAME
);