Until now, the number of L1 client channels was set statically in the
configuration. This static configuration also assumed the same number of
cached and uncached channels per tile. As we plan to move towards
heterogenous multicore systems, this restriction should be removed.
This commit changes the generator so that number of channels per tile
can be independently set (using cde.Parameters.alterPartial).
The OuterMemorySystem will dynamically compute the number of cached and
uncached channels by summing the number of each kind of channel per core.
We are planning on switching to a TileLink interconnect throughout and
convert to AXI only on the very edge. Therefore, we need to get rid of
all the existing AXI masters other than the TileLink to AXI converter.
* Get rid of DMA engine for now
* Connect RTC to TileLink interconnect instead of AXI interconnect
The backup memory port doesn't work on multi-channel configurations, it
just screws up the Nasti tag bits. This patch always instantiates a
single-channel backup memory port, which relies on the memory channel
selector to only enable a single memory channel when the backup memory
port is enabled. There are some assertions to make sure this happens,
as otherwise memory gets silently corrupted.
While this is a bit of a hack, the backup memory port will be going away
soon so I don't want to spend a whole lot of time fixing it. The
generated hardware is actually very similar: we used to elaborate a
Nasti arbiter inside the backup memory support, now there's one outside
of it instead.
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).
