This was recently changed to write out physical addresses for SCR file entries,
but to bring up the chip we need SCR offsets so we can write the uncore SCR
file over HTIF. This changes the map generator to generate both.
Without this change things happened to work anyway because the high bits were
getting dropped by the SCR file.
We used to just be writing the SCR anyway, but now that the SCR maps are
automatically defined VCS will detect the missing SCR and bail out when
compiling test harness code. This patch just doesn't write the HTIF SCR when
there isn't one.
We're building a chip with 8 memory channels. Since this will require a
complicated test setup we want to also be able to bring up the chip with fewer
memory channels. This commit adds a SCR that controls the number of active
memory channels on a chip. Toggling this SCR will scramble memory and drop
Nasti messages, so it's only possible to change while the chip is booting.
By default this just adds a 1-bit SCR, which essentially no extra logic.
When multiple memory channel configurations are enabled at elaboration time, a
NastiMemoryInterconnect is generated for each channel configuration. The
number of outstanding misses is increased to coorespond to the maximum number
of banks per memory channel (added as a parameter), which I believe is
necessary to avoid deadlock in the memory system.
A configuration is added that supports 8 memory channels but has only 1 enabled
by default.
This uses the new SCRFile changes to generate a header file containing a list
of all the SCRs in a core to remove the magic constant "63" (the HTIF clock
divider control register) and replace it with a generated number (which is
still 63).
Right now there's no way to ensure that SCR addresses don't conflict within
RocketChip. Since upstream only has one of them this isn't a big deal, but we
want to add a whole bunch more to control all the IP on Hurricane.
This patch adds some Scala code to allocate registers inside the SCR file,
ensure they don't conflict, to provide names for SCRs, attach registers to the
SCR file, and generate a C header file that contains the addresses of every SCR
on a chip.
With this patch we'll be able to get rid of that constant in the testbench.
This also allows us to kill one of the Raven diffs, which is does pretty much
the same thing (just in a second SCR file, and hacked in).
