[BUG] relative file name leads to $readmem file not found (Verilator model)

[CharKeaney]

Is there an existing core-v-mcu bug for this?

• I have searched the existing bug issues

Bug Description

The file loaded in module generic_memory by $readmemh is a relative file location, and so not found if the Verilator model is not run in an expected directory. In our example, the problem was triggered trying to open mem_init/TOP.core_v_mcu.i_soc_domain.l2_ram_i.bank_sram_pri0_i.u0.mem.

We tested this using the prototype embdebug Verilator model GDB server. The error message is as follows.

charlie@troughton:~/src/install/bin$ ./embdebug --soname /home/charlie/src/embdebug-target-core-v/target/target.so --rsp-port 1234
Loading ITarget interface from dynamic library: /home/charlie/src/embdebug-target-core-v/target/target.so
Timescale 1ns / 1ns
Listening for RSP on port 1234
Remote debugging from host 127.0.0.1
TOP.core_v_mcu.i_soc_domain.l2_ram_i.bank_sram_pri0_i.u0
%Error: mem_init/TOP.core_v_mcu.i_soc_domain.l2_ram_i.bank_sram_pri0_i.u0.mem:0: $readmem file not found
Aborting...
Aborted (core dumped)

Changing this to run from the build/openhwgroup.org_systems_core-v-mcu_0/model-lib-verilator directory, caused correct behavior as follows:

charlie@troughton:~/src/core-v-mcu/build/openhwgroup.org_systems_core-v-mcu_0/model-lib-verilator$ ../../../../install/bin/embdebug --soname /home/charlie/src/embdebug-target-core-v/target/target.so --rsp-port 1234
Loading ITarget interface from dynamic library: /home/charlie/src/embdebug-target-core-v/target/target.so
Timescale 1ns / 1ns
Listening for RSP on port 1234
Remote debugging from host 127.0.0.1
TOP.core_v_mcu.i_soc_domain.l2_ram_i.bank_sram_pri0_i.u0
TOP.core_v_mcu.i_soc_domain.l2_ram_i.bank_sram_pri1_i.u0
TOP.core_v_mcu.i_soc_domain.l2_ram_i.CUTS[0].bank_i.u0
TOP.core_v_mcu.i_soc_domain.l2_ram_i.CUTS[1].bank_i.u0
TOP.core_v_mcu.i_soc_domain.l2_ram_i.CUTS[2].bank_i.u0
TOP.core_v_mcu.i_soc_domain.l2_ram_i.CUTS[3].bank_i.u0
...

The solution is either to ensure the $readmemh uses the absolute filename, or that there is a way to specify the base for any relative file references.

[jeremybennett]

@gmartin102 or @davideschiavone is this something where you might be able to suggest the most effective solution? Thanks.