mei: txe: reduce suspend/resume time

HW has to be in known state before the initialisation
sequence is started. The polling step for settling aliveness
was set to 200ms while in practise this can be done in up to 30msecs.

Cc: <stable@vger.kernel.org> #3.18+
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Barak Yoresh <barak.yoresh@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/hw-txe.c

@@ -16,6 +16,7 @@
 
 #include <linux/pci.h>
 #include <linux/jiffies.h>
+#include <linux/ktime.h>
 #include <linux/delay.h>
 #include <linux/kthread.h>
 #include <linux/irqreturn.h>
@@ -218,26 +219,25 @@ static u32 mei_txe_aliveness_get(struct mei_device *dev)
  *
  * Polls for HICR_HOST_ALIVENESS_RESP.ALIVENESS_RESP to be set
  *
- * Return: > 0 if the expected value was received, -ETIME otherwise
+ * Return: 0 if the expected value was received, -ETIME otherwise
  */
 static int mei_txe_aliveness_poll(struct mei_device *dev, u32 expected)
 {
 	struct mei_txe_hw *hw = to_txe_hw(dev);
-	int t = 0;
+	ktime_t stop, start;
 
+	start = ktime_get();
+	stop = ktime_add(start, ms_to_ktime(SEC_ALIVENESS_WAIT_TIMEOUT));
 	do {
 		hw->aliveness = mei_txe_aliveness_get(dev);
 		if (hw->aliveness == expected) {
 			dev->pg_event = MEI_PG_EVENT_IDLE;
-			dev_dbg(dev->dev,
-				"aliveness settled after %d msecs\n", t);
-			return t;
+			dev_dbg(dev->dev, "aliveness settled after %lld usecs\n",
+				ktime_to_us(ktime_sub(ktime_get(), start)));
+			return 0;
 		}
-		mutex_unlock(&dev->device_lock);
-		msleep(MSEC_PER_SEC / 5);
-		mutex_lock(&dev->device_lock);
-		t += MSEC_PER_SEC / 5;
-	} while (t < SEC_ALIVENESS_WAIT_TIMEOUT);
+		usleep_range(20, 50);
+	} while (ktime_before(ktime_get(), stop));
 
 	dev->pg_event = MEI_PG_EVENT_IDLE;
 	dev_err(dev->dev, "aliveness timed out\n");