[S390] cio: Add chsc subchannel driver.

This patch adds a driver for subchannels of type chsc.

A device /dev/chsc is created which may be used to issue ioctls to:
- obtain information about the machine's I/O configuration
- dynamically change the machine's I/O configuration via
  asynchronous chsc commands

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index 34b38fb7c2f..6ebf1b50736 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -877,6 +877,12 @@ __clear_io_subchannel_easy(struct subchannel_id schid)
 	return -EBUSY;
 }
 
+static void __clear_chsc_subchannel_easy(void)
+{
+	/* It seems we can only wait for a bit here :/ */
+	udelay_reset(100);
+}
+
 static int pgm_check_occured;
 
 static void cio_reset_pgm_check_handler(void)
@@ -920,6 +926,9 @@ static int __shutdown_subchannel_easy(struct subchannel_id schid, void *data)
 			if (__clear_io_subchannel_easy(schid))
 				goto out; /* give up... */
 			break;
+		case SUBCHANNEL_TYPE_CHSC:
+			__clear_chsc_subchannel_easy();
+			break;
 		default:
 			/* No default clear strategy */
 			break;