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rocket-chip/src
Wesley W. Terpstra b59880fe8e
Fragmenter: add an option for earlyAck only on PutFulls (#1095)
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.
2017-11-08 15:31:19 -08:00
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main/scala Fragmenter: add an option for earlyAck only on PutFulls (#1095) 2017-11-08 15:31:19 -08:00