On MPC86xx the watchdog could be enabled only at power-on-reset, and
could not be disabled afterwards. We must ping the watchdog from the
kernel until the userspace handles it.
MPC83xx CPUs are only differ in a way that watchdog could be disabled
once, but after it was enabled via software it becomes just the same
as MPC86xx.
Thus, to support MPC86xx I added the kernel timer which pings the
watchdog until the userspace opens it.
Since we implemented the timer, now we're able to implement proper
handling for the CONFIG_WATCHDOG_NOWAYOUT case, for MPC83xx and MPC86xx.
Also move the probe code into subsys_initcall, because we want start
pinging the watchdog ASAP, and misc devices are available in
subsys_initcall.
Signed-off-by: Anton Vorontsov <[EMAIL PROTECTED]>
---
drivers/watchdog/Kconfig | 4 +-
drivers/watchdog/mpc83xx_wdt.c | 63 ++++++++++++++++++++++++++++++++++++----
2 files changed, 59 insertions(+), 8 deletions(-)
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 254d115..2929055 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -683,8 +683,8 @@ config 8xx_WDT
depends on 8xx
config 83xx_WDT
- tristate "MPC83xx Watchdog Timer"
- depends on PPC_83xx
+ tristate "MPC83xx/MPC86xx Watchdog Timer"
+ depends on PPC_83xx || PPC_86xx
config MV64X60_WDT
tristate "MV64X60 (Marvell Discovery) Watchdog Timer"
diff --git a/drivers/watchdog/mpc83xx_wdt.c b/drivers/watchdog/mpc83xx_wdt.c
index b16c5cd..14492a7 100644
--- a/drivers/watchdog/mpc83xx_wdt.c
+++ b/drivers/watchdog/mpc83xx_wdt.c
@@ -1,10 +1,12 @@
/*
- * mpc83xx_wdt.c - MPC83xx watchdog userspace interface
+ * mpc83xx_wdt.c - MPC83xx/MPC86xx watchdog userspace interface
*
* Authors: Dave Updegraff <[EMAIL PROTECTED]>
* Kumar Gala <[EMAIL PROTECTED]>
* Attribution: from 83xx_wst: Florian Schirmer <[EMAIL PROTECTED]>
* ..and from sc520_wdt
+ * Copyright (c) 2008 MontaVista Software, Inc.
+ * Anton Vorontsov <[EMAIL PROTECTED]>
*
* Note: it appears that you can only actually ENABLE or DISABLE the thing
* once after POR. Once enabled, you cannot disable, and vice versa.
@@ -22,6 +24,7 @@
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/watchdog.h>
+#include <linux/timer.h>
#include <asm/io.h>
#include <asm/uaccess.h>
@@ -48,6 +51,11 @@ static int reset = 1;
module_param(reset, bool, 0);
MODULE_PARM_DESC(reset, "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 =
reset");
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
+ "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
/*
* We always prescale, but if someone really doesn't want to they can set this
* to 0
@@ -67,6 +75,22 @@ static void mpc83xx_wdt_keepalive(void)
spin_unlock(&wdt_spinlock);
}
+static void mpc83xx_wdt_timer_ping(unsigned long arg);
+static DEFINE_TIMER(wdt_timer, mpc83xx_wdt_timer_ping, 0, 0);
+
+static void mpc83xx_wdt_timer_ping(unsigned long arg)
+{
+ mpc83xx_wdt_keepalive();
+ /* We're pinging it twice faster than needed, just to be sure. */
+ mod_timer(&wdt_timer, jiffies + HZ * timeout_sec / 2);
+}
+
+static void mpc83xx_wdt_pr_warn(const char *msg)
+{
+ pr_crit("mpc83xx_wdt: %s, expect the %s soon!\n", msg,
+ reset ? "reset" : "machine check exception");
+}
+
static ssize_t mpc83xx_wdt_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
@@ -82,7 +106,8 @@ static int mpc83xx_wdt_open(struct inode *inode, struct file
*file)
return -EBUSY;
/* Once we start the watchdog we can't stop it */
- __module_get(THIS_MODULE);
+ if (nowayout)
+ __module_get(THIS_MODULE);
/* Good, fire up the show */
if (prescale)
@@ -94,13 +119,17 @@ static int mpc83xx_wdt_open(struct inode *inode, struct
file *file)
out_be32(&wd_base->swcrr, tmp);
+ del_timer_sync(&wdt_timer);
+
return nonseekable_open(inode, file);
}
static int mpc83xx_wdt_release(struct inode *inode, struct file *file)
{
- printk(KERN_CRIT "Unexpected close, not stopping watchdog!\n");
- mpc83xx_wdt_keepalive();
+ if (!nowayout)
+ mpc83xx_wdt_timer_ping(0);
+ else
+ mpc83xx_wdt_pr_warn("watchdog closed");
clear_bit(0, &wdt_is_open);
return 0;
}
@@ -152,6 +181,7 @@ static int __devinit mpc83xx_wdt_probe(struct
platform_device *dev)
struct resource *r;
int ret;
unsigned int *freq = dev->dev.platform_data;
+ bool enabled;
/* get a pointer to the register memory */
r = platform_get_resource(dev, IORESOURCE_MEM, 0);
@@ -168,6 +198,15 @@ static int __devinit mpc83xx_wdt_probe(struct
platform_device *dev)
goto err_out;
}
+ enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN;
+#ifdef CONFIG_PPC_86xx
+ if (!enabled) {
+ dev_info(&dev->dev, "could not be enabled by software\n");
+ ret = -ENOSYS;
+ goto err_unmap;
+ }
+#endif
+
ret = misc_register(&mpc83xx_wdt_miscdev);
if (ret) {
printk(KERN_ERR "cannot register miscdev on minor=%d "
@@ -185,6 +224,15 @@ static int __devinit mpc83xx_wdt_probe(struct
platform_device *dev)
printk(KERN_INFO "WDT driver for MPC83xx initialized. "
"mode:%s timeout=%d (%d seconds)\n",
reset ? "reset":"interrupt", timeout, timeout_sec);
+
+ /*
+ * If the watchdog was previously enabled or we're running on
+ * MPC86xx, we should ping the wdt from the kernel until the
+ * userspace handles it.
+ */
+ if (enabled)
+ mpc83xx_wdt_timer_ping(0);
+
return 0;
err_unmap:
@@ -217,14 +265,17 @@ static int __init mpc83xx_wdt_init(void)
static void __exit mpc83xx_wdt_exit(void)
{
+ /* might happen only on !nowayout */
+ mpc83xx_wdt_pr_warn("module removed");
+ del_timer_sync(&wdt_timer);
platform_driver_unregister(&mpc83xx_wdt_driver);
}
-module_init(mpc83xx_wdt_init);
+subsys_initcall(mpc83xx_wdt_init);
module_exit(mpc83xx_wdt_exit);
MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
-MODULE_DESCRIPTION("Driver for watchdog timer in MPC83xx uProcessor");
+MODULE_DESCRIPTION("Driver for watchdog timer in MPC83xx/MPC86xx uProcessor");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("platform:mpc83xx_wdt");
--
1.5.5.1
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