watchdog: Add WDIOC_GETTIMELEFT ioctl support to w83627 watchdog driver

Add WDIOC_GETTIMELEFT ioctl allowing you to check how much time is left
on the watchdog counter before a reset occurs.

Signed-off-by: Greg Lee <glee [at] swspec.com>
Signed-off-by: Padraig Brady <P@draigbrady.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@google.com>

1 files changed, 27 insertions, 6 deletions

diff --git a/drivers/watchdog/w83627hf_wdt.c b/drivers/watchdog/w83627hf_wdt.c
index e5c91d4404e..dd5d6754875 100644
--- a/drivers/watchdog/w83627hf_wdt.c
+++ b/drivers/watchdog/w83627hf_wdt.c
@@ -142,7 +142,7 @@ static void w83627hf_init(void)
         w83627hf_unselect_wd_register();
 }
 
-static void wdt_ctrl(int timeout)
+static void wdt_set_time(int timeout)
 {
         spin_lock(&io_lock);
 
@@ -158,13 +158,13 @@ static void wdt_ctrl(int timeout)
 
 static int wdt_ping(void)
 {
-        wdt_ctrl(timeout);
+        wdt_set_time(timeout);
         return 0;
 }
 
 static int wdt_disable(void)
 {
-        wdt_ctrl(0);
+        wdt_set_time(0);
         return 0;
 }
 
@@ -176,6 +176,24 @@ static int wdt_set_heartbeat(int t)
         return 0;
 }
 
+static int wdt_get_time(void)
+{
+        int timeleft;
+
+        spin_lock(&io_lock);
+
+        w83627hf_select_wd_register();
+
+        outb_p(0xF6, WDT_EFER);    /* Select CRF6 */
+        timeleft = inb_p(WDT_EFDR); /* Read Timeout counter to CRF6 */
+
+        w83627hf_unselect_wd_register();
+
+        spin_unlock(&io_lock);
+
+        return timeleft;
+}
+
 static ssize_t wdt_write(struct file *file, const char __user *buf,
                                                 size_t count, loff_t *ppos)
 {
@@ -202,7 +220,7 @@ static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
         void __user *argp = (void __user *)arg;
         int __user *p = argp;
-        int new_timeout;
+        int timeval;
         static const struct watchdog_info ident = {
                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
                                                         WDIOF_MAGICCLOSE,
@@ -238,14 +256,17 @@ static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
                 wdt_ping();
                 break;
         case WDIOC_SETTIMEOUT:
-                if (get_user(new_timeout, p))
+                if (get_user(timeval, p))
                         return -EFAULT;
-                if (wdt_set_heartbeat(new_timeout))
+                if (wdt_set_heartbeat(timeval))
                         return -EINVAL;
                 wdt_ping();
                 /* Fall */
         case WDIOC_GETTIMEOUT:
                 return put_user(timeout, p);
+        case WDIOC_GETTIMELEFT:
+                timeval = wdt_get_time();
+                return put_user(timeval, p);
         default:
                 return -ENOTTY;
         }