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path: root/drivers/s390/cio/cio.c
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Diffstat (limited to 'drivers/s390/cio/cio.c')
-rw-r--r--drivers/s390/cio/cio.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index b5620e818d6b..690b8547e828 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -925,18 +925,32 @@ void reipl_ccw_dev(struct ccw_dev_id *devid)
int __init cio_get_iplinfo(struct cio_iplinfo *iplinfo)
{
+ static struct chsc_sda_area sda_area __initdata;
struct subchannel_id schid;
struct schib schib;
schid = *(struct subchannel_id *)&S390_lowcore.subchannel_id;
if (!schid.one)
return -ENODEV;
+
+ if (schid.ssid) {
+ /*
+ * Firmware should have already enabled MSS but whoever started
+ * the kernel might have initiated a channel subsystem reset.
+ * Ensure that MSS is enabled.
+ */
+ memset(&sda_area, 0, sizeof(sda_area));
+ if (__chsc_enable_facility(&sda_area, CHSC_SDA_OC_MSS))
+ return -ENODEV;
+ }
if (stsch_err(schid, &schib))
return -ENODEV;
if (schib.pmcw.st != SUBCHANNEL_TYPE_IO)
return -ENODEV;
if (!schib.pmcw.dnv)
return -ENODEV;
+
+ iplinfo->ssid = schid.ssid;
iplinfo->devno = schib.pmcw.dev;
iplinfo->is_qdio = schib.pmcw.qf;
return 0;