[S390] Add Documentation/s390/00-INDEX.

[safe/jmp/linux-2.6] / drivers / char / watchdog / at32ap700x_wdt.c

diff --git a/drivers/char/watchdog/at32ap700x_wdt.c b/drivers/char/watchdog/at32ap700x_wdt.c
index 8abe1c7..54a5161 100644 (file)
--- a/drivers/char/watchdog/at32ap700x_wdt.c
+++ b/drivers/char/watchdog/at32ap700x_wdt.c
@@ -18,10 +18,23 @@
 #include <linux/watchdog.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
+#include <linux/spinlock.h>
 
 #define TIMEOUT_MIN            1
-#define TIMEOUT_DEFAULT                CONFIG_AT32AP700X_WDT_TIMEOUT
 #define TIMEOUT_MAX            2
+#define TIMEOUT_DEFAULT                TIMEOUT_MAX
+
+/* module parameters */
+static int timeout =  TIMEOUT_DEFAULT;
+module_param(timeout, int, 0);
+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
@@ -41,21 +54,27 @@
 
 struct wdt_at32ap700x {
        void __iomem            *regs;
+       spinlock_t              io_lock;
        int                     timeout;
-       int                     users;
+       unsigned long           users;
        struct miscdevice       miscdev;
 };
 
 static struct wdt_at32ap700x *wdt;
+static char expect_release;
 
 /*
  * Disable the watchdog.
  */
 static inline void at32_wdt_stop(void)
 {
-       unsigned long psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f);
+       unsigned long psel;
+
+       spin_lock(&wdt->io_lock);
+       psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f);
        wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55));
        wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa));
+       spin_unlock(&wdt->io_lock);
 }
 
 /*
@@ -66,12 +85,14 @@ static inline void at32_wdt_start(void)
        /* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */
        unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe;
 
+       spin_lock(&wdt->io_lock);
        wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
                        | WDT_BF(CTRL_PSEL, psel)
                        | WDT_BF(CTRL_KEY, 0x55));
        wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
                        | WDT_BF(CTRL_PSEL, psel)
                        | WDT_BF(CTRL_KEY, 0xaa));
+       spin_unlock(&wdt->io_lock);
 }
 
 /*
@@ -79,7 +100,9 @@ static inline void at32_wdt_start(void)
  */
 static inline void at32_wdt_pat(void)
 {
+       spin_lock(&wdt->io_lock);
        wdt_writel(wdt, CLR, 0x42);
+       spin_unlock(&wdt->io_lock);
 }
 
 /*
@@ -95,15 +118,19 @@ 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;
 }
 
@@ -129,7 +156,9 @@ 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,
 };
 
 /*
@@ -184,10 +213,35 @@ 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;
 }
 
@@ -228,16 +282,17 @@ static int __init at32_wdt_probe(struct platform_device *pdev)
                dev_dbg(&pdev->dev, "could not map I/O memory\n");
                goto err_free;
        }
+       spin_lock_init(&wdt->io_lock);
        wdt->users = 0;
        wdt->miscdev.minor = WATCHDOG_MINOR;
        wdt->miscdev.name = "watchdog";
        wdt->miscdev.fops = &at32_wdt_fops;
 
-       if (at32_wdt_settimeout(TIMEOUT_DEFAULT)) {
-               at32_wdt_settimeout(TIMEOUT_MAX);
+       if (at32_wdt_settimeout(timeout)) {
+               at32_wdt_settimeout(TIMEOUT_DEFAULT);
                dev_dbg(&pdev->dev,
                        "default timeout invalid, set to %d sec.\n",
-                       TIMEOUT_MAX);
+                       TIMEOUT_DEFAULT);
        }
 
        ret = misc_register(&wdt->miscdev);
@@ -248,7 +303,9 @@ 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\n", wdt->regs);
+       dev_info(&pdev->dev,
+               "AT32AP700X WDT at 0x%p, timeout %d sec (nowayout=%d)\n",
+               wdt->regs, wdt->timeout, nowayout);
 
        return 0;
 
@@ -263,6 +320,10 @@ 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);