2 * Watchdog driver for Cirrus Logic EP93xx family of devices.
4 * Copyright (c) 2004 Ray Lehtiniemi
5 * Copyright (c) 2006 Tower Technologies
6 * Based on ep93xx driver, bits from alim7101_wdt.c
8 * Authors: Ray Lehtiniemi <rayl@mail.com>,
9 * Alessandro Zummo <a.zummo@towertech.it>
11 * Copyright (c) 2012 H Hartley Sweeten <hsweeten@visionengravers.com>
12 * Convert to a platform device and use the watchdog framework API
14 * This file is licensed under the terms of the GNU General Public
15 * License version 2. This program is licensed "as is" without any
16 * warranty of any kind, whether express or implied.
18 * This watchdog fires after 250msec, which is a too short interval
19 * for us to rely on the user space daemon alone. So we ping the
20 * wdt each ~200msec and eventually stop doing it if the user space
25 * - Test last reset from watchdog status
26 * - Add a few missing ioctls
29 #include <linux/platform_device.h>
30 #include <linux/module.h>
31 #include <linux/miscdevice.h>
32 #include <linux/watchdog.h>
33 #include <linux/timer.h>
36 #define WDT_VERSION "0.4"
38 /* default timeout (secs) */
39 #define WDT_TIMEOUT 30
41 static bool nowayout
= WATCHDOG_NOWAYOUT
;
42 module_param(nowayout
, bool, 0);
43 MODULE_PARM_DESC(nowayout
, "Watchdog cannot be stopped once started");
45 static unsigned int timeout
= WDT_TIMEOUT
;
46 module_param(timeout
, uint
, 0);
47 MODULE_PARM_DESC(timeout
,
48 "Watchdog timeout in seconds. (1<=timeout<=3600, default="
49 __MODULE_STRING(WDT_TIMEOUT
) ")");
51 static void __iomem
*mmio_base
;
52 static struct timer_list timer
;
53 static unsigned long next_heartbeat
;
55 #define EP93XX_WATCHDOG 0x00
56 #define EP93XX_WDSTATUS 0x04
58 /* reset the wdt every ~200ms - the heartbeat of the device is 0.250 seconds*/
59 #define WDT_INTERVAL (HZ/5)
61 static void ep93xx_wdt_timer_ping(unsigned long data
)
63 if (time_before(jiffies
, next_heartbeat
))
64 writel(0x5555, mmio_base
+ EP93XX_WATCHDOG
);
66 /* Re-set the timer interval */
67 mod_timer(&timer
, jiffies
+ WDT_INTERVAL
);
70 static int ep93xx_wdt_start(struct watchdog_device
*wdd
)
72 next_heartbeat
= jiffies
+ (timeout
* HZ
);
74 writel(0xaaaa, mmio_base
+ EP93XX_WATCHDOG
);
75 mod_timer(&timer
, jiffies
+ WDT_INTERVAL
);
80 static int ep93xx_wdt_stop(struct watchdog_device
*wdd
)
82 del_timer_sync(&timer
);
83 writel(0xaa55, mmio_base
+ EP93XX_WATCHDOG
);
88 static int ep93xx_wdt_keepalive(struct watchdog_device
*wdd
)
91 next_heartbeat
= jiffies
+ (timeout
* HZ
);
96 static const struct watchdog_info ep93xx_wdt_ident
= {
97 .options
= WDIOF_CARDRESET
|
100 .identity
= "EP93xx Watchdog",
103 static struct watchdog_ops ep93xx_wdt_ops
= {
104 .owner
= THIS_MODULE
,
105 .start
= ep93xx_wdt_start
,
106 .stop
= ep93xx_wdt_stop
,
107 .ping
= ep93xx_wdt_keepalive
,
110 static struct watchdog_device ep93xx_wdt_wdd
= {
111 .info
= &ep93xx_wdt_ident
,
112 .ops
= &ep93xx_wdt_ops
,
115 static int ep93xx_wdt_probe(struct platform_device
*pdev
)
117 struct resource
*res
;
121 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
125 if (!devm_request_mem_region(&pdev
->dev
, res
->start
,
126 resource_size(res
), pdev
->name
))
129 mmio_base
= devm_ioremap(&pdev
->dev
, res
->start
, resource_size(res
));
133 if (timeout
< 1 || timeout
> 3600) {
134 timeout
= WDT_TIMEOUT
;
136 "timeout value must be 1<=x<=3600, using %d\n",
140 val
= readl(mmio_base
+ EP93XX_WATCHDOG
);
141 ep93xx_wdt_wdd
.bootstatus
= (val
& 0x01) ? WDIOF_CARDRESET
: 0;
142 ep93xx_wdt_wdd
.timeout
= timeout
;
144 watchdog_set_nowayout(&ep93xx_wdt_wdd
, nowayout
);
146 setup_timer(&timer
, ep93xx_wdt_timer_ping
, 1);
148 err
= watchdog_register_device(&ep93xx_wdt_wdd
);
153 "EP93XX watchdog, driver version " WDT_VERSION
"%s\n",
154 (val
& 0x08) ? " (nCS1 disable detected)" : "");
159 static int ep93xx_wdt_remove(struct platform_device
*pdev
)
161 watchdog_unregister_device(&ep93xx_wdt_wdd
);
165 static struct platform_driver ep93xx_wdt_driver
= {
167 .owner
= THIS_MODULE
,
168 .name
= "ep93xx-wdt",
170 .probe
= ep93xx_wdt_probe
,
171 .remove
= ep93xx_wdt_remove
,
174 module_platform_driver(ep93xx_wdt_driver
);
176 MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>,"
177 "Alessandro Zummo <a.zummo@towertech.it>,"
178 "H Hartley Sweeten <hsweeten@visionengravers.com>");
179 MODULE_DESCRIPTION("EP93xx Watchdog");
180 MODULE_LICENSE("GPL");
181 MODULE_VERSION(WDT_VERSION
);