struct ccw_dev_id — unique identifier for ccw devices
struct ccw_dev_id {
u8 ssid;
u16 devno;
};
This structure is not directly based on any hardware structure. The
hardware identifies a device by its device number and its subchannel,
which is in turn identified by its id. In order to get a unique identifier
for ccw devices across subchannel sets, struct ccw_dev_id has been
introduced.