s390x/css: Unplug handler of virtual css bridge

The previous patch moved virtual css bridge and bus out from
virtio-ccw, but kept the direct reference of virtio-ccw specific
unplug function inside css-bridge.c.

To make the virtual css bus and bridge useful for non-virtio devices,
this introduces a common unplug function pointer "unplug" to call
specific virtio-ccw unplug parts. Thus, the tight coupling to
virtio-ccw can be removed.

This unplug pointer is a member of CCWDeviceClass, which is introduced
as an abstract device layer called "ccw-device". This layer is between
DeviceState and specific devices which are plugged in virtual css bus,
like virtio-ccw device. The specific unplug handlers should be assigned
to "unplug" during initialization.

Signed-off-by: Jing Liu <liujbjl@linux.vnet.ibm.com>
Reviewed-by: Sascha Silbe <silbe@linux.vnet.ibm.com>
Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Reviewed-by: Yi Min Zhao <zyimin@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

1 files changed, 8 insertions, 6 deletions

diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
index a54284c74a..2e2664f22e 100644
--- a/hw/s390x/ipl.c
+++ b/hw/s390x/ipl.c
@@ -221,12 +221,14 @@ static bool s390_gen_initial_iplb(S390IPLState *ipl)
 
     dev_st = get_boot_device(0);
     if (dev_st) {
-        VirtioCcwDevice *ccw_dev = (VirtioCcwDevice *) object_dynamic_cast(
-            OBJECT(qdev_get_parent_bus(dev_st)->parent),
+        VirtioCcwDevice *virtio_ccw_dev = (VirtioCcwDevice *)
+            object_dynamic_cast(OBJECT(qdev_get_parent_bus(dev_st)->parent),
                 TYPE_VIRTIO_CCW_DEVICE);
         SCSIDevice *sd = (SCSIDevice *) object_dynamic_cast(OBJECT(dev_st),
                                                             TYPE_SCSI_DEVICE);
-        if (ccw_dev) {
+        if (virtio_ccw_dev) {
+            CcwDevice *ccw_dev = CCW_DEVICE(virtio_ccw_dev);
+
             ipl->iplb.len = cpu_to_be32(S390_IPLB_MIN_CCW_LEN);
             ipl->iplb.blk0_len =
                 cpu_to_be32(S390_IPLB_MIN_CCW_LEN - S390_IPLB_HEADER_LEN);
@@ -238,7 +240,7 @@ static bool s390_gen_initial_iplb(S390IPLState *ipl)
             SCSIBus *bus = scsi_bus_from_device(sd);
             VirtIOSCSI *vdev = container_of(bus, VirtIOSCSI, bus);
             VirtIOSCSICcw *scsi_ccw = container_of(vdev, VirtIOSCSICcw, vdev);
-            VirtioCcwDevice *ccw = &scsi_ccw->parent_obj;
+            CcwDevice *ccw_dev = CCW_DEVICE(scsi_ccw);
 
             ipl->iplb.len = cpu_to_be32(S390_IPLB_MIN_QEMU_SCSI_LEN);
             ipl->iplb.blk0_len =
@@ -247,8 +249,8 @@ static bool s390_gen_initial_iplb(S390IPLState *ipl)
             ipl->iplb.scsi.lun = cpu_to_be32(sd->lun);
             ipl->iplb.scsi.target = cpu_to_be16(sd->id);
             ipl->iplb.scsi.channel = cpu_to_be16(sd->channel);
-            ipl->iplb.scsi.devno = cpu_to_be16(ccw->sch->devno);
-            ipl->iplb.scsi.ssid = ccw->sch->ssid & 3;
+            ipl->iplb.scsi.devno = cpu_to_be16(ccw_dev->sch->devno);
+            ipl->iplb.scsi.ssid = ccw_dev->sch->ssid & 3;
             return true;
         }
     }