s390/cio: add helper to query utility strings per given ccw device

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

2 files changed, 32 insertions, 0 deletions

diff --git a/arch/s390/include/asm/ccwdev.h b/arch/s390/include/asm/ccwdev.h
index 20bce136b2e5..a29dd430fb40 100644
--- a/arch/s390/include/asm/ccwdev.h
+++ b/arch/s390/include/asm/ccwdev.h
@@ -231,4 +231,5 @@ int ccw_device_siosl(struct ccw_device *);
 extern void ccw_device_get_schid(struct ccw_device *, struct subchannel_id *);
 
 struct channel_path_desc_fmt0 *ccw_device_get_chp_desc(struct ccw_device *, int);
+u8 *ccw_device_get_util_str(struct ccw_device *cdev, int chp_idx);
 #endif /* _S390_CCWDEV_H_ */
diff --git a/drivers/s390/cio/device_ops.c b/drivers/s390/cio/device_ops.c
index aecfebb74157..4435ae0b3027 100644
--- a/drivers/s390/cio/device_ops.c
+++ b/drivers/s390/cio/device_ops.c
@@ -473,6 +473,36 @@ struct channel_path_desc_fmt0 *ccw_device_get_chp_desc(struct ccw_device *cdev,
 }
 
 /**
+ * ccw_device_get_util_str() - return newly allocated utility strings
+ * @cdev: device to obtain the utility strings for
+ * @chp_idx: index of the channel path
+ *
+ * On success return a newly allocated copy of the utility strings
+ * associated with the given channel path. Return %NULL on error.
+ */
+u8 *ccw_device_get_util_str(struct ccw_device *cdev, int chp_idx)
+{
+        struct subchannel *sch = to_subchannel(cdev->dev.parent);
+        struct channel_path *chp;
+        struct chp_id chpid;
+        u8 *util_str;
+
+        chp_id_init(&chpid);
+        chpid.id = sch->schib.pmcw.chpid[chp_idx];
+        chp = chpid_to_chp(chpid);
+
+        util_str = kmalloc(sizeof(chp->desc_fmt3.util_str), GFP_KERNEL);
+        if (!util_str)
+                return NULL;
+
+        mutex_lock(&chp->lock);
+        memcpy(util_str, chp->desc_fmt3.util_str, sizeof(chp->desc_fmt3.util_str));
+        mutex_unlock(&chp->lock);
+
+        return util_str;
+}
+
+/**
  * ccw_device_get_id() - obtain a ccw device id
  * @cdev: device to obtain the id for
  * @dev_id: where to fill in the values
@@ -682,3 +712,4 @@ EXPORT_SYMBOL(ccw_device_start_key);
 EXPORT_SYMBOL(ccw_device_get_ciw);
 EXPORT_SYMBOL(ccw_device_get_path_mask);
 EXPORT_SYMBOL_GPL(ccw_device_get_chp_desc);
+EXPORT_SYMBOL_GPL(ccw_device_get_util_str);