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update README

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Howard Mao 2016-08-19 11:39:30 -07:00
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@ -166,67 +166,45 @@ to stress-test both the core and uncore portions of the design.
In addition to submodules, which are tracked as different git repositories, In addition to submodules, which are tracked as different git repositories,
the rocket-chip Chisel code base is factored into a number of Scala packages. the rocket-chip Chisel code base is factored into a number of Scala packages.
Here is a brief description Here is a brief description of what can be found in each package:
of what can be found in each package:
* **rocket** * **rocket**
([https://github.com/ucb-bar/rocket](https://github.com/ucb-bar/rocket)): The rocket package holds the actual source code of the Rocket core.
The rocket repository holds the actual source code of the Rocket core.
Note that the L1 blocking I$ and the L1 non-blocking D$ are considered Note that the L1 blocking I$ and the L1 non-blocking D$ are considered
part of the core, and hence we keep the L1 cache source code in this part of the core, and hence we keep the L1 cache source code in this
repository. This repository is not meant to stand alone; it needs to be repository. This repository is not meant to stand alone; it needs to be
included in a chip repository (e.g. rocket-chip) that instantiates the included in a chip repository (e.g. rocket-chip) that instantiates the
core within a memory system and connects it to the outside world. core within a memory system and connects it to the outside world.
* **uncore** * **uncore**
([https://github.com/ucb-bar/uncore](https://github.com/ucb-bar/uncore)): This package implements the uncore logic, such as the L2 coherence hub
This repository implements the uncore logic, such as the coherence hub
(the agent that keeps multiple L1 D$ coherent). The definition of the (the agent that keeps multiple L1 D$ coherent). The definition of the
coherent interfaces between tiles ("tilelink") and the debug interface coherent interfaces between tiles ("tilelink") and the debug interface
also live in this repository. also live in this repository.
* **junctions** * **junctions**
([https://github.com/ucb-bar/junctions](https://github.com/ucb-bar/junctions)): This package contains code and
This repository contains code and
converters for various bus protocols and interfaces. converters for various bus protocols and interfaces.
* **groundtest** * **groundtest**
([https://github.com/ucb-bar/groundtest](https://github.com/ucb-bar/groundtest)): This package contains code which can test the uncore by generating randomized
This repository contains code which can test the uncore by generating randomized
instruction streams. It replaces the rocket processor with an instruction instruction streams. It replaces the rocket processor with an instruction
stream generator to stress-test the uncore portions of the design. stream generator to stress-test the uncore portions of the design.
* **coreplex**
This package pieces together the parts of a working coreplex, including
the rocket tiles, L1-to-L2 network, L2 coherence agents, and internal devices
like the debug unit and boot ROM.
* **rocketchip**
The top-level package instantiates the coreplex and drops in any
external-facing devices. It also includes clock-crossers and converters
from TileLink to external bus protocols (like AXI or AHB).
### <a name="what_toplevel"></a>The Top Level Module ### <a name="what_toplevel"></a>The Top Level Module
Next, take a look at rocket-chip's src/main/scala directory. Take a look at the src/main/scala/rocketchip directory.
This directory has the Chisel source files including the top level This directory has the Chisel source files including the top level
RocketChip.scala, which RocketChip.scala.
instantiates both a Rocket core and the uncore logic, and then glues
them together. Here's a brief overview of source files found in the
rocket-chip repository:
* **RocketChip.scala**: Top-level source file (Top is the top-level
module name), which instantiates a Rocket core, uncore logic, and glues
them together.
* **Network.scala**: This source file holds the crossbar network used in
the uncore for multi-core implementations.
* **Configs.scala**: This holds all the rocket-chip parameters.
Probably this file is the most important file for external users. We
will revisit this topic in the next section "How should I use the Rocket
chip generator?", and will also post a more detailed explanation of the
parameter infrastructure in the near future.
* **Backends.scala**: An example of how the Chisel compiler's VLSI
backend can be extended to route a pin named "init" to all SRAM blocks
used in the design. This separation cleans up the source RTL of the
design, since we don't need to add all the vendor-specific stuff in the
Chisel source code, yet still can correctly hook up our particular
SRAMs. The transformation is just a "compiler pass" in the Chisel
backend that happens as the compiler translates the Chisel source code
down to Verilog. Pretty neat huh?
* **Vlsi.scala**: This file is pretty specific to our tapeouts. It
implements logic to interface with an arbitrary number of slow
single-ended digital I/Os when implementing a test chip.
Take a look at the top-level I/O pins. Open up Take a look at the top-level I/O pins. Open up
src/main/scala/RocketChip.scala, and search for TopIO. You will read the src/main/scala/rocketchip/RocketChip.scala, and search for TopIO.
following: You will read the following:
/** Top-level io for the chip */ /** Top-level io for the chip */
class BasicTopIO(implicit val p: Parameters) extends ParameterizedBundle()(p) class BasicTopIO(implicit val p: Parameters) extends ParameterizedBundle()(p)
@ -260,13 +238,6 @@ configuration of the design, these may be visible as AXI or AHB.
* **Interrupts interface (interrupts)**: This interface is used to * **Interrupts interface (interrupts)**: This interface is used to
deliver external interrupts to the processor core. deliver external interrupts to the processor core.
Of course, there's a lot more in the submodules, but
this should be enough to get you started with the Rocket chip
generator. We will keep documenting more about our designs in the
respective README of each submodules, release notes, and even blog
posts. In the mean time, please post questions to the hw-dev mailing
list.
## <a name="how"></a> How should I use the Rocket chip generator? ## <a name="how"></a> How should I use the Rocket chip generator?
Chisel can generate code for three targets: a high-performance Chisel can generate code for three targets: a high-performance