Fundamental new features:
* Added tile package: This package is intended to hold components re-usable across different types of tile. Will be the future location of TL2-RoCC accelerators and new diplomatic versions of intra-tile interfaces.
* Adopted [ModuleName]Params convention: Code base was very inconsistent about what to name case classes that provide parameters to modules. Settled on calling them [ModuleName]Params to distinguish them from config.Parameters and config.Config. So far applied mostly only to case classes defined within rocket and tile.
* Defined RocketTileParams: A nested case class containing case classes for all the components of a tile (L1 caches and core). Allows all such parameters to vary per-tile.
* Defined RocketCoreParams: All the parameters that can be varied per-core.
* Defined L1CacheParams: A trait defining the parameters common to L1 caches, made concrete in different derived case classes.
* Defined RocketTilesKey: A sequence of RocketTileParams, one for every tile to be created.
* Provided HeterogeneousDualCoreConfig: An example of making a heterogeneous chip with two cores, one big and one little.
* Changes to legacy code: ReplacementPolicy moved to package util. L1Metadata moved to package tile. Legacy L2 cache agent removed because it can no longer share the metadata array implementation with the L1. Legacy GroundTests on life support.
Additional changes that got rolled in along the way:
* rocket: Fix critical path through BTB for I$ index bits > pgIdxBits
* coreplex: tiles connected via :=*
* groundtest: updated to use TileParams
* tilelink: cache cork requirements are relaxed to allow more cacheless masters
We want to keep the banks split in the outer SoC if there is an L3.
Furthermore, each channel might go to different memory subsystems,
like DDR/HMC/Zero, from rocketchip.
A lot of utility code was just being imported willy-nilly from one
package to another. This moves the common code into util to make things
more sensible. The code moved were
* The AsyncQueue and AsyncDecoupledCrossing from junctions.
* All of the code in rocket's util.scala
* The BlackBox asynchronous reset registers from uncore.tilelink2
* The implicit definitions from uncore.util
We have a handful of TileLink-related helper objects
(wrappers, unwrappers, width adapters, and enqueuers). Previously, using
them could be error-prone, because you had to make sure the implicit
parameters they took in had the same TLId as the TileLinkIO bundles
passed in as inputs. This is rather silly, we should just use the
parameters in the bundle.
This API makes it much more readable when you have multiple adapters
combined into a single line. The arguments for each adapter stay
beside the adapter.
For example, this:
peripheryBus.node := TLWidthWidget(TLBuffer(TLAtomicAutomata()(TLHintHandler(legacy.node))), legacy.tlDataBytes)
becomes this:
peripheryBus.node := TLWidthWidget(legacy.tlDataBytes)(TLBuffer()(TLAtomicAutomata()(TLHintHandler()(legacy.node))))