* TLToAXI4: fix WaR for single-source FIFO masters
* TLToAXI4: fix potential counter overflow => WaR hazard
If you have a FIFO master with 2^n-1 sources that performs early
source re-use, the old code could potentially break FIFO order.
- Put correctness responsibility on Frontend, not IBuf, for improved
separation of concerns. Frontend must detect case that the BTB
predicts a taken branch in the middle of an instruction.
- Pass BTB information down pipeline unconditionally, fixing case that
screws up the branch history when the BTB misses and the instruction
is misaligned.
- Remove jumpInFrontend option; it's now unconditional.
- Default to one-bit counters in the BHT. For tiny BHTs like these, it's
more resource efficient to have a larger index space than to have
hysteresis.
Fragmenter: add a third case for earlyAck (PutFulls only)
It seems quite common to have a device that is backed by ECC. When
performing a multibeat PutPartial, these devices can exhibit their
first error on the last beat (if it had an incomplete write mask
for that beat, which required read-write-modifying corrupted data).
Generally, these devices have ECC granularity <= the bus width. In
those cases, if you send a PutFull, the first beat carries the
error value for the whole burst. Consider:
If the PutFull was below the granularity, it was a single beat.
If the PutFull was multi-beat, it exceeds the granularity.
Therefore, an important variation on the earlyAck optimization is
the case where only PutFulls receive an earlyAck.
When switching ports, the bypass stalls new messages until all
outstanding messages have received their responses. However, this
stall must NOT stop the remaining beats of a partially sent request.
* tilelink: ToAXI4 should format it's error message
* WithStatelessBridge: mark the memory bus incoherent and cacheable
... and hope that the user doesn't put more than one master down.
* JTAG: Use sorted map for stability
Otherwise the generated FIRRTL/Verilog is non deterministic
* jtag : parens for clarity
* jtag: Use deterministic ListMap and sort for stability
* JTAG: use slightly clearer SortedMap (clearer to me anyway)
* jtag: whitespace cleanup
From the AHB spec:
"A slave only has to provide valid data when a transfer completes with an OKAY
response. ERROR responses do not require valid read data."
