[kvm-unit-tests PATCH v5 2/6] s390x: css: simplifications of the tests

[Pierre Morel <pmorel@linux.ibm.com>]

In order to ease the writing of tests based on:
- interrupt
- enabling a subchannel
- using multiple I/O on a channel without disabling it

We do the following simplifications:
- the I/O interrupt handler is registered on CSS initialization
- We do not enable again a subchannel in senseid if it is already
  enabled
- we add a css_enabled() function to test if a subchannel is enabled

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
---
 lib/s390x/css.h     |  1 +
 lib/s390x/css_lib.c | 37 ++++++++++++++++++++++++++-----------
 s390x/css.c         |  3 +++
 3 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/lib/s390x/css.h b/lib/s390x/css.h
index fe68b7d..71d91f0 100644
--- a/lib/s390x/css.h
+++ b/lib/s390x/css.h
@@ -278,6 +278,7 @@ int css_enumerate(void);
 
 #define IO_SCH_ISC      3
 int css_enable(int schid, int isc);
+bool css_enabled(int schid);
 
 /* Library functions */
 int start_ccw1_chain(unsigned int sid, struct ccw1 *ccw);
diff --git a/lib/s390x/css_lib.c b/lib/s390x/css_lib.c
index f46e871..41134dc 100644
--- a/lib/s390x/css_lib.c
+++ b/lib/s390x/css_lib.c
@@ -161,6 +161,31 @@ out:
 	return schid;
 }
 
+/*
+ * css_enabled: report if the subchannel is enabled
+ * @schid: Subchannel Identifier
+ * Return value:
+ *   true if the subchannel is enabled
+ *   false otherwise
+ */
+bool css_enabled(int schid)
+{
+	struct pmcw *pmcw = &schib.pmcw;
+	int cc;
+
+	cc = stsch(schid, &schib);
+	if (cc) {
+		report_info("stsch: updating sch %08x failed with cc=%d",
+			    schid, cc);
+		return false;
+	}
+
+	if (!(pmcw->flags & PMCW_ENABLE)) {
+		report_info("stsch: sch %08x not enabled", schid);
+		return false;
+	}
+	return true;
+}
 /*
  * css_enable: enable the subchannel with the specified ISC
  * @schid: Subchannel Identifier
@@ -210,18 +235,8 @@ retry:
 	/*
 	 * Read the SCHIB again to verify the enablement
 	 */
-	cc = stsch(schid, &schib);
-	if (cc) {
-		report_info("stsch: updating sch %08x failed with cc=%d",
-			    schid, cc);
-		return cc;
-	}
-
-	if ((pmcw->flags & flags) == flags) {
-		report_info("stsch: sch %08x successfully modified after %d retries",
-			    schid, retry_count);
+	if (css_enabled(schid))
 		return 0;
-	}
 
 	if (retry_count++ < MAX_ENABLE_RETRIES) {
 		mdelay(10); /* the hardware was not ready, give it some time */
diff --git a/s390x/css.c b/s390x/css.c
index 12036b3..069c2be 100644
--- a/s390x/css.c
+++ b/s390x/css.c
@@ -143,6 +143,9 @@ error_senseid:
 
 static void css_init(void)
 {
+	assert(register_io_int_func(css_irq_io) == 0);
+	lowcore_ptr->io_int_param = 0;
+
 	report(get_chsc_scsc(), "Store Channel Characteristics");
 }
 
-- 
2.17.1