[WATCHDOG] at32ap700x_wdt.c - Add nowayout + MAGICCLOSE features
Add nowayout + MAGICCLOSE features.
Signed-off-by: Hans-Christian Egtvedt <hcegtvedt@atmel.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: Andrew Morton <akpm@linux-foundation.org>
diff --git a/drivers/char/watchdog/at32ap700x_wdt.c b/drivers/char/watchdog/at32ap700x_wdt.c
index 6e7c958..fcd55c6 100644
--- a/drivers/char/watchdog/at32ap700x_wdt.c
+++ b/drivers/char/watchdog/at32ap700x_wdt.c
@@ -30,6 +30,11 @@
"Timeout value. Limited to be 1 or 2 seconds. (default="
__MODULE_STRING(TIMEOUT_DEFAULT) ")");
+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) ")");
+
/* Watchdog registers and write/read macro */
#define WDT_CTRL 0x00
#define WDT_CTRL_EN 0
@@ -54,6 +59,7 @@
};
static struct wdt_at32ap700x *wdt;
+static char expect_release;
/*
* Disable the watchdog.
@@ -102,15 +108,19 @@
}
/*
- * Close the watchdog device. If CONFIG_WATCHDOG_NOWAYOUT is _not_ defined then
- * the watchdog is also disabled.
+ * Close the watchdog device.
*/
static int at32_wdt_close(struct inode *inode, struct file *file)
{
-#ifndef CONFIG_WATCHDOG_NOWAYOUT
- at32_wdt_stop();
-#endif
+ if (expect_release == 42) {
+ at32_wdt_stop();
+ } else {
+ dev_dbg(wdt->miscdev.parent,
+ "Unexpected close, not stopping watchdog!\n");
+ at32_wdt_pat();
+ }
clear_bit(1, &wdt->users);
+ expect_release = 0;
return 0;
}
@@ -136,7 +146,9 @@
static struct watchdog_info at32_wdt_info = {
.identity = "at32ap700x watchdog",
- .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+ .options = WDIOF_SETTIMEOUT |
+ WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE,
};
/*
@@ -191,10 +203,35 @@
return ret;
}
-static ssize_t at32_wdt_write(struct file *file, const char *data, size_t len,
- loff_t *ppos)
+static ssize_t at32_wdt_write(struct file *file, const char __user *data,
+ size_t len, loff_t *ppos)
{
- at32_wdt_pat();
+ /* See if we got the magic character 'V' and reload the timer */
+ if (len) {
+ if (!nowayout) {
+ size_t i;
+
+ /*
+ * note: just in case someone wrote the magic
+ * character five months ago...
+ */
+ expect_release = 0;
+
+ /*
+ * scan to see whether or not we got the magic
+ * character
+ */
+ for (i = 0; i != len; i++) {
+ char c;
+ if (get_user(c, data+i))
+ return -EFAULT;
+ if (c == 'V')
+ expect_release = 42;
+ }
+ }
+ /* someone wrote to us, we should pat the watchdog */
+ at32_wdt_pat();
+ }
return len;
}
@@ -255,8 +292,9 @@
platform_set_drvdata(pdev, wdt);
wdt->miscdev.parent = &pdev->dev;
- dev_info(&pdev->dev, "AT32AP700X WDT at 0x%p, timeout %d sec\n",
- wdt->regs, wdt->timeout);
+ dev_info(&pdev->dev,
+ "AT32AP700X WDT at 0x%p, timeout %d sec (nowayout=%d)\n",
+ wdt->regs, wdt->timeout, nowayout);
return 0;
@@ -271,6 +309,10 @@
static int __exit at32_wdt_remove(struct platform_device *pdev)
{
if (wdt && platform_get_drvdata(pdev) == wdt) {
+ /* Stop the timer before we leave */
+ if (!nowayout)
+ at32_wdt_stop();
+
misc_deregister(&wdt->miscdev);
iounmap(wdt->regs);
kfree(wdt);