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authorFrank Munzert <munzert@de.ibm.com>2009-06-16 10:30:39 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2009-06-16 10:31:16 +0200
commit3ef32e62cb55785f6f1b5ad7290744f74bdadaf0 (patch)
tree1ce1cfb22c145bfc1594d90a8fd117c004d68eee /drivers/s390/char/tape_core.c
parent9f62fa1618987e9fadb2eef86d35ef168ddf5a1f (diff)
[S390] pm: tape power management callbacks
Signed-off-by: Frank Munzert <munzert@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390/char/tape_core.c')
-rw-r--r--drivers/s390/char/tape_core.c52
1 files changed, 51 insertions, 1 deletions
diff --git a/drivers/s390/char/tape_core.c b/drivers/s390/char/tape_core.c
index 8a109f3b69c6..3ebaa8eb5c86 100644
--- a/drivers/s390/char/tape_core.c
+++ b/drivers/s390/char/tape_core.c
@@ -3,7 +3,7 @@
* basic function of the tape device driver
*
* S390 and zSeries version
- * Copyright IBM Corp. 2001,2006
+ * Copyright IBM Corp. 2001, 2009
* Author(s): Carsten Otte <cotte@de.ibm.com>
* Michael Holzheu <holzheu@de.ibm.com>
* Tuan Ngo-Anh <ngoanh@de.ibm.com>
@@ -380,6 +380,55 @@ tape_cleanup_device(struct tape_device *device)
}
/*
+ * Suspend device.
+ *
+ * Called by the common I/O layer if the drive should be suspended on user
+ * request. We refuse to suspend if the device is loaded or in use for the
+ * following reason:
+ * While the Linux guest is suspended, it might be logged off which causes
+ * devices to be detached. Tape devices are automatically rewound and unloaded
+ * during DETACH processing (unless the tape device was attached with the
+ * NOASSIGN or MULTIUSER option). After rewind/unload, there is no way to
+ * resume the original state of the tape device, since we would need to
+ * manually re-load the cartridge which was active at suspend time.
+ */
+int tape_generic_pm_suspend(struct ccw_device *cdev)
+{
+ struct tape_device *device;
+
+ device = cdev->dev.driver_data;
+ if (!device) {
+ return -ENODEV;
+ }
+
+ DBF_LH(3, "(%08x): tape_generic_pm_suspend(%p)\n",
+ device->cdev_id, device);
+
+ if (device->medium_state != MS_UNLOADED) {
+ pr_err("A cartridge is loaded in tape device %s, "
+ "refusing to suspend\n", dev_name(&cdev->dev));
+ return -EBUSY;
+ }
+
+ spin_lock_irq(get_ccwdev_lock(device->cdev));
+ switch (device->tape_state) {
+ case TS_INIT:
+ case TS_NOT_OPER:
+ case TS_UNUSED:
+ spin_unlock_irq(get_ccwdev_lock(device->cdev));
+ break;
+ default:
+ pr_err("Tape device %s is busy, refusing to "
+ "suspend\n", dev_name(&cdev->dev));
+ spin_unlock_irq(get_ccwdev_lock(device->cdev));
+ return -EBUSY;
+ }
+
+ DBF_LH(3, "(%08x): Drive suspended.\n", device->cdev_id);
+ return 0;
+}
+
+/*
* Set device offline.
*
* Called by the common I/O layer if the drive should set offline on user
@@ -1273,6 +1322,7 @@ EXPORT_SYMBOL(tape_generic_remove);
EXPORT_SYMBOL(tape_generic_probe);
EXPORT_SYMBOL(tape_generic_online);
EXPORT_SYMBOL(tape_generic_offline);
+EXPORT_SYMBOL(tape_generic_pm_suspend);
EXPORT_SYMBOL(tape_put_device);
EXPORT_SYMBOL(tape_get_device_reference);
EXPORT_SYMBOL(tape_state_verbose);