3 files changed, 58 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index d29b6d926a42..880f882160e2 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -370,6 +370,9 @@ and is between 256 and 4096 characters. It is defined in the file
                         configured.  Potentially dangerous and should only be
                         used if you are entirely sure of the consequences.
 
+        ccw_timeout_log [S390]
+                        See Documentation/s390/CommonIO for details.
+
         checkreqprot    [SELINUX] Set initial checkreqprot flag value.
                         Format: { "0" | "1" }
                         See security/selinux/Kconfig help text.
diff --git a/Documentation/s390/CommonIO b/Documentation/s390/CommonIO
index 86320aa3fb0b..8fbc0a852870 100644
--- a/Documentation/s390/CommonIO
+++ b/Documentation/s390/CommonIO
@@ -4,6 +4,11 @@ S/390 common I/O-Layer - command line parameters, procfs and debugfs entries
 Command line parameters
 -----------------------
 
+* ccw_timeout_log
+
+  Enable logging of debug information in case of ccw device timeouts.
+
+
 * cio_msg = yes | no
   
   Determines whether information on found devices and sensed device 
diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c
index bfad421cda66..31c0f7885161 100644
--- a/drivers/s390/cio/device_fsm.c
+++ b/drivers/s390/cio/device_fsm.c
@@ -25,6 +25,8 @@
 #include "ioasm.h"
 #include "chp.h"
 
+static int timeout_log_enabled;
+
 int
 device_is_online(struct subchannel *sch)
 {
@@ -82,6 +84,52 @@ int device_trigger_verify(struct subchannel *sch)
         return 0;
 }
 
+static int __init ccw_timeout_log_setup(char *unused)
+{
+        timeout_log_enabled = 1;
+        return 1;
+}
+
+__setup("ccw_timeout_log", ccw_timeout_log_setup);
+
+static void ccw_timeout_log(struct ccw_device *cdev)
+{
+        struct schib schib;
+        struct subchannel *sch;
+        int cc;
+
+        sch = to_subchannel(cdev->dev.parent);
+        cc = stsch(sch->schid, &schib);
+
+        printk(KERN_WARNING "cio: ccw device timeout occurred at %llx, "
+               "device information:\n", get_clock());
+        printk(KERN_WARNING "cio: orb:\n");
+        print_hex_dump(KERN_WARNING, "cio:  ", DUMP_PREFIX_NONE, 16, 1,
+                       &sch->orb, sizeof(sch->orb), 0);
+        printk(KERN_WARNING "cio: ccw device bus id: %s\n", cdev->dev.bus_id);
+        printk(KERN_WARNING "cio: subchannel bus id: %s\n", sch->dev.bus_id);
+        printk(KERN_WARNING "cio: subchannel lpm: %02x, opm: %02x, "
+               "vpm: %02x\n", sch->lpm, sch->opm, sch->vpm);
+
+        if ((void *)(addr_t)sch->orb.cpa == &sch->sense_ccw ||
+            (void *)(addr_t)sch->orb.cpa == cdev->private->iccws)
+                printk(KERN_WARNING "cio: last channel program (intern):\n");
+        else
+                printk(KERN_WARNING "cio: last channel program:\n");
+
+        print_hex_dump(KERN_WARNING, "cio:  ", DUMP_PREFIX_NONE, 16, 1,
+                       (void *)(addr_t)sch->orb.cpa, sizeof(struct ccw1), 0);
+        printk(KERN_WARNING "cio: ccw device state: %d\n",
+               cdev->private->state);
+        printk(KERN_WARNING "cio: store subchannel returned: cc=%d\n", cc);
+        printk(KERN_WARNING "cio: schib:\n");
+        print_hex_dump(KERN_WARNING, "cio:  ", DUMP_PREFIX_NONE, 16, 1,
+                       &schib, sizeof(schib), 0);
+        printk(KERN_WARNING "cio: ccw device flags:\n");
+        print_hex_dump(KERN_WARNING, "cio:  ", DUMP_PREFIX_NONE, 16, 1,
+                       &cdev->private->flags, sizeof(cdev->private->flags), 0);
+}
+
 /*
  * Timeout function. It just triggers a DEV_EVENT_TIMEOUT.
  */
@@ -92,6 +140,8 @@ ccw_device_timeout(unsigned long data)
 
         cdev = (struct ccw_device *) data;
         spin_lock_irq(cdev->ccwlock);
+        if (timeout_log_enabled)
+                ccw_timeout_log(cdev);
         dev_fsm_event(cdev, DEV_EVENT_TIMEOUT);
         spin_unlock_irq(cdev->ccwlock);
 }