This guide will show you how to change FireSim to build a dual-core Rocket RISC-V core. You can use this guide to modify Chipyard[^2] to build your custom architectures.
This work was funded by the iARPA AGILE Program. [^1]
This work was funded by the IARPA AGILE Program. [^1]
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# Building a Dual-Core Rocket
In this example, we will be modifying FireSim to generate a dual-core RISC-V Rocket Core (`vitis_firesim_rocket_dualcore_no_nic`) and booting it up on the attached FPGA. Generating bitstreams for the Alveo U250 can take a **few hours** to complete, so it's recommended to do your work in a [persistent session](home#opening-a-persistent-session-on-bxe-firesim-nodes).
In this example, we will be modifying FireSim to generate a dual-core RISC-V Rocket Core (`alveo_u250_firesim_rocket_dualcore_nic`) and booting it up on the attached FPGA. Generating bitstreams for the Alveo U250 can take a **few hours** to complete, so it's recommended to do your work in a [persistent session](home#opening-a-persistent-session-on-bxe-firesim-nodes).
## Modifying FireSim Configuration Files
FireSim has two `.yaml` files that describes the designs available to build, and well as where to build new designs.
Both of these files can be found in `~/firesim/deploy`. Examples of unmodified FireSim configuration files can be found in `~/firesim/deploy/sample-backup-configs`.
Both of these files can be found in `$FIRESIM_ROOT/deploy`. Examples of unmodified FireSim configuration files can be found in `$FIRESIM_ROOT/deploy/sample-backup-configs`.
### `~/firesim/deploy/config_build.yaml`
### `$FIRESIM_ROOT/deploy/config_build.yaml`
This files configures the build environment for FireSim. This tells the tools where to build designs, what base shell to use, and what designs to build.
First, we'll tell FireSim where to build our designs. Edit the `build-farm` section to resemble the following:
This tells FireSim to place all of the build files in `/home/bxeuser/firesim/deploy/build_dir/`. You can change this to any location you'd like.
This tells FireSim to place all of the build files in `/home/bxeuser/firesim/FIRESIM_BUILD_DIR` on the run farm hosts. You can change this to any location you'd like.
Next we need to tell FireSim which designs we would like to build. `builds_to_run` lists all of the recipes that we'd like FireSim to build from scratch. Since we only want FireSim to build our `vitis_firesim_rocket_dualcore_no_nic` recipe, we make sure we add it and comment out the other recipes. Here's what the `builds_to_run` section should look like:
Next we need to tell FireSim which designs we would like to build. `builds_to_run` lists all of the recipes that we'd like FireSim to build from scratch. Since we only want FireSim to build a `alveo_u250_firesim_rocket_dualcore_nic` recipe, we make sure we add it and comment out the other recipes. Here's what the `builds_to_run` section should look like:
```yaml
builds_to_run:
# this section references builds defined in config_build_recipes.yaml
# if you add a build here, it will be built when you run buildbitstream
# Unnetworked designs use a three-domain configuration
# Tiles: 1600 MHz
# <Rational Crossing>
# Uncore: 800 MHz
# <Async Crossing>
# DRAM : 1000 MHz
# - firesim_rocket_quadcore_no_nic_l2_llc4mb_ddr3
# - firesim_boom_singlecore_no_nic_l2_llc4mb_ddr3
# All NIC-based designs use the legacy FireSim frequency selection, with the
# tiles and uncore running at 3.2 GHz to sustain 200Gb theoretical NIC BW
Next we need add our `vitis_firesim_rocket_dualcore_no_nic` to the list of FireSim hardware recipes. The recipe is what FireSim uses to tell Chipyard what to design to build, as well as any FPGA specific parameters. The top of the file has schema for all of the parameters available.
Next we need add our `alveo_u250_firesim_rocket_dualcore_nic` to the list of FireSim hardware recipes. The recipe is what FireSim uses to tell Chipyard what to design to build, as well as any FPGA specific parameters. The top of the file has schema for all of the parameters available.
Add the following to the end of `~/firesim/deploy/config_build_recipes.yaml`:
Add the following to the end of `$FIRESIM_ROOT/deploy/config_build_recipes.yaml`:
We have now completed configuring FireSim. The `TARGET_CONFIG` section is the specific design in Chipyard we'd like to build. However, this design doesn't exist in Chipyard...
...
...
@@ -183,12 +190,12 @@ We have now completed configuring FireSim. The `TARGET_CONFIG` section is the sp
## Creating a Design with Chipyard Mixins
Chipyard allows us to use their library of standard architecture and hardware components to build designs. These are called *Mixins*, and the list of components is out of scope for this tutorial. For now, we'll just use these to design a dual-core Rocket core.
Let's add our design to the list of designs available to FireSim. Open `~/firesim/target-design/chipyard/generators/firechip/src/main/scala/TargetConfigs.scala` and add the following to the end of the file:
Let's add our design to the list of designs available to FireSim. Open `$CHIPYARD_ROOT/generators/firechip/src/main/scala/TargetConfigs.scala` and add the following to the end of the file:
@@ -198,68 +205,52 @@ class FireSimDualRocketMMIOOnlyConfig extends Config(
And that's it! We're ready to build our design!
## Generating a Bitstream
With the FireSim build environment and Chipyard design configured, we're ready to launch the build. With FireSim loaded into our enivornment (`source sourceme-f1-manager.sh --skip-ssh-setup`), we can launch a build.
With the FireSim build environment and Chipyard design configured, we're ready to launch the build. With FireSim loaded into our environment (`source sourceme-manager.sh --skip-ssh-setup`), we can launch a build.
```bash
cd~/firesim
# source sourceme-f1-manager.sh --skip-ssh-setup
cd$FIRESIM_ROOT
# source sourceme-manager.sh --skip-ssh-setup
firesim buildbitstream
```
As stated before, this may take **MANY HOURS** to complete. Grab yourself a cup of your favorite beverage and let the machine build. You should see the following successful build message when done:
When complete, you'll find a bitstream in your build directory: `/home/bxeuser/firesim/deploy/build_dir//platforms/vitis/cl_FireSim-FireSimDualRocketMMIOOnlyConfig-BaseVitisConfig/bitstream/build_dir.xilinx_u250_gen3x16_xdma_4_1_202210_1/firesim.xclbin`
This is important for when we want to run the simulation. Speaking of which...
# Running a Custom Design
Now that the build is complete, we need to tell FireSim that this design is available to be run. We'll add `vitis_firesim_rocket_dualcore_no_nic` to FireSim's hardware database, then configure the simulation to use the new design.
Now that the build is complete, we need to tell FireSim that this design is available to be run. We'll add `alveo_u250_firesim_rocket_dualcore_nic` to FireSim's hardware database, then configure the simulation to use the new design.
## `~/firesim/deploy/config_hwdb.yaml`
## `$FIRESIM_ROOT/deploy/config_hwdb.yaml`
Using the path generated in the build step, we add an entry to the hardware database. Add the following to the end of the file:
Now we're ready to deploy this design in the simulation. We modify this file to tell FireSim what the target design we're going to simulate. In the `target_config` section, change the `default_hw_config` to point to our new design, `vitis_firesim_rocket_dualcore_no_nic`. It should resemble this:
## `$FIRESIM_ROOT/deploy/config_runtime.yaml`
Now we're ready to deploy this design in the simulation. We modify this file to tell FireSim what the target design we're going to simulate. In the `target_config` section, change the `default_hw_config` to point to our new design, `alveo_u250_firesim_rocket_dualcore_nic`. It should resemble this:
