[S390] pm: chsc subchannel driver power management callbacks

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/chsc_sch.c

 /*
  * Driver for s390 chsc subchannels
  *
- * Copyright IBM Corp. 2008
+ * Copyright IBM Corp. 2008, 2009
+ *
  * Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
  *
  */
@@ -112,6 +113,31 @@ static void chsc_subchannel_shutdown(struct subchannel *sch)
 	cio_disable_subchannel(sch);
 }
 
+static int chsc_subchannel_prepare(struct subchannel *sch)
+{
+	int cc;
+	struct schib schib;
+	/*
+	 * Don't allow suspend while the subchannel is not idle
+	 * since we don't have a way to clear the subchannel and
+	 * cannot disable it with a request running.
+	 */
+	cc = stsch(sch->schid, &schib);
+	if (!cc && scsw_stctl(&schib.scsw))
+		return -EAGAIN;
+	return 0;
+}
+
+static int chsc_subchannel_freeze(struct subchannel *sch)
+{
+	return cio_disable_subchannel(sch);
+}
+
+static int chsc_subchannel_restore(struct subchannel *sch)
+{
+	return cio_enable_subchannel(sch, (u32)(unsigned long)sch);
+}
+
 static struct css_device_id chsc_subchannel_ids[] = {
 	{ .match_flags = 0x1, .type =SUBCHANNEL_TYPE_CHSC, },
 	{ /* end of list */ },
@@ -125,6 +151,10 @@ static struct css_driver chsc_subchannel_driver = {
 	.probe = chsc_subchannel_probe,
 	.remove = chsc_subchannel_remove,
 	.shutdown = chsc_subchannel_shutdown,
+	.prepare = chsc_subchannel_prepare,
+	.freeze = chsc_subchannel_freeze,
+	.thaw = chsc_subchannel_restore,
+	.restore = chsc_subchannel_restore,
 	.name = "chsc_subchannel",
 };