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).
* DMA frontend-backend communication tunneled over TileLink/AXI
* Split MMIO and Mem requests in l1tol2net instead of in AXI interconnect
* Don't make NIOMSHRs configurable. Fixed at 1.
* Connect accelerator-internal CSRs into the CSR file
* Make mtvec register configurable and writeable
In addition to the fix, there are several additions to the
RegressionTest module. The set of regressions is now parameterized and
split into ones for the cache and ones for the broadcast hub.
