[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, 28 insertions, 0 deletions

diff --git a/include/asm-s390/schid.h b/include/asm-s390/schid.h
new file mode 100644
index 000000000000..5017ffa78e04
--- /dev/null
+++ b/include/asm-s390/schid.h
@@ -0,0 +1,28 @@
+#ifndef ASM_SCHID_H
+#define ASM_SCHID_H
+
+struct subchannel_id {
+        __u32 cssid : 8;
+        __u32 : 4;
+        __u32 m : 1;
+        __u32 ssid : 2;
+        __u32 one : 1;
+        __u32 sch_no : 16;
+} __attribute__ ((packed, aligned(4)));
+
+
+/* Helper function for sane state of pre-allocated subchannel_id. */
+static inline void
+init_subchannel_id(struct subchannel_id *schid)
+{
+        memset(schid, 0, sizeof(struct subchannel_id));
+        schid->one = 1;
+}
+
+static inline int
+schid_equal(struct subchannel_id *schid1, struct subchannel_id *schid2)
+{
+        return !memcmp(schid1, schid2, sizeof(struct subchannel_id));
+}
+
+#endif /* ASM_SCHID_H */