You will need to bring up a full system partition and inventory the machine using
lsslot -c slot
this will show you slots, then you will need to track it from slots since the HMC doesn't see devices.
My p570's happen to have hdisks in slot T-12
U7879.001.DQD1XXX-P1-T12 Logical I/O Slot pci19 sisscsia1
root@myhost:/home/root/-> lsdev -p pci19
sisscsia1 Available 0J-08 PCI-X Ultra320 SCSI Adapter
root@myhost:/home/root/-> lsdev -p sisscsia1
scsi1 Available 0J-08-00 PCI-X Ultra320 SCSI Adapter bus
root@myhost:/home/root/-> lsdev -p scsi1
hdisk0 Available 0J-08-00-4,0 16 Bit LVD SCSI Disk Drive
hdisk1 Available 0J-08-00-5,0 16 Bit LVD SCSI Disk Drive
ses1 Available 0J-08-00-15,0 SCSI Enclosure Services Device
so in this case, I would give CECDQD -slot T12, to which ever lpar I wanted to give these hdisk.
Does this help? The XXX in U7879.001.DQD1XXX-P1-T12 tells you which CEC (drawer) the slot is in. This is called the S/N under the cover in each CEC.