Hi ARM folks. We're trying to make sure we're setting up the CNTFRQ register properly in a fast model CPU we're hooking up to gem5, and I believe we have the simulator part of that set up properly. We have the input for the non core components of the model running at a fixed frequency, and during initialization we set the CNTFRQ register of each context to that frequency before starting the guest software
My colleague TK noticed, however, that the ARM bootloader writes a compiled in value into the CNTFRQ register, and that will clobber the value we put there. In gem5, writing to the register CNTFRQ actually configures the frequency of that timer. That is not in line with what the documentation says, where CNTFRQ is supposed to be a read-only type register which just reports the frequency to software and doesn't do anything to control that frequency. Should gem5 be doing that? Is that how the generic system timer should be configured? Why was it done that way? Can we change it so gem5 sets it up like we do with the fast model, where the frequency is set outside of the host software and the CNTFRQ register just has a value jammed into it for software to discover? Gabe _______________________________________________ gem5-dev mailing list gem5-dev@gem5.org http://m5sim.org/mailman/listinfo/gem5-dev
