diff options
| -rw-r--r-- | drivers/char/watchdog/at32ap700x_wdt.c | 64 |
1 files changed, 53 insertions, 11 deletions
diff --git a/drivers/char/watchdog/at32ap700x_wdt.c b/drivers/char/watchdog/at32ap700x_wdt.c index 6e7c9588b1b9..fcd55c600b87 100644 --- a/drivers/char/watchdog/at32ap700x_wdt.c +++ b/drivers/char/watchdog/at32ap700x_wdt.c @@ -30,6 +30,11 @@ MODULE_PARM_DESC(timeout, "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 @@ struct wdt_at32ap700x { }; static struct wdt_at32ap700x *wdt; +static char expect_release; /* * Disable the watchdog. @@ -102,15 +108,19 @@ static int at32_wdt_open(struct inode *inode, struct file *file) } /* - * 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 int at32_wdt_settimeout(int time) 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 @@ static int at32_wdt_ioctl(struct inode *inode, struct file *file, 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 @@ static int __init at32_wdt_probe(struct platform_device *pdev) 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 @@ err_free: 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); |