To map the slave service path to channel in a design with multiple transceiver instances, use marker_get_info in the Transceiver Toolkit.
Refer to the following example:
#list all slaves by get_service_paths slave, the return results have index starts from 0:
get_service_paths slave
#set the target slave by lindex number, lindex 3 is for the 4th slave
set m [lindex [get_service_paths slave] 3]
# use marker_get_info to show full information
set marker_info [marker_get_info $m]
It may return results as follows:
TYPE_NAME altera_xcvr_native_s10.slave FULL_HPATH u1|top_xcvr_native_s10_0|top_xcvr_native_s10_0|alt_xcvr_native_optional_rcfg_logic BASE_ADDRESS 16384 ADDRESS_SPAN 16384
TYPE xcvr_native_s10 indicates transceiver channel for Stratix® 10 devices, FULL_HPATH shows the instance in the design. You can identify the channel from the path information.