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OpenLane__Documentation

Linux Commands for installing prerequisites of OPENLANE

For UBUNTU Systems >=22.04 LTS

sudo apt install python3-pip -> this is for installing python3
sudo apt-get install git -> installing git for github repository
sudo apt-get install yosys -> installing RTL synthesis framework
sudo apt-get install make ->installing make file
sudo apt-get install klayout -> installing IC layout editor
sudo snap install docker -> installing docker
pip3 install fusesoc -> installing python library called FuseSoC
sudo apt-get install verilator -> installing Verilator
sudo apt-get install magic ->installing magic, a layout tool
sudo apt-get install opensta ->installing opensta, a GUI based web server
sudo apt-get install vim -> installing vim editor
sudo apt-get install gtkwave -> to view simulation of verilog codes
sudo apt install -y build-essential python3 python3-venv python3-pip

Conda download is also mandatory otherwise your openlane won’t download any pdks

• For this go to your Mozilla browser in Ubuntu • Visit https://docs.conda.io/en/latest/miniconda.html image

• Choose python 3.8 under Linux installers image

• Your file gets downloaded in /Downloads in Ubuntu

• Now go to your terminal and type these commands

 cd ..
 cd Downloads 
 sh Miniconda3-latest-Linux-x86_64.sh  or bash Miniconda3-latest-Linux-x86_64.sh (Your miniconda file will have a similar name)

After running above command Miniconda file opens in the terminal just keep pressing enter until you see do you agree to license terms You say Y/Yes to continue

The download starts automatically and it will show in the end that download was successful

Restart the terminal to see the changes to terminal.

Commands for removal of old UBUNTU docker (Only for versions < 22.04)

Docker versions which supports UBUNTU versions <22.04 requires these commands to be run in their pc

  sudo apt-get remove docker docker-engine docker.io containerd runc    --> Uninstall Old docker versions 
  sudo apt-get update         -->update apt package index
  sudo apt-get install \
ca-certificates \
curl \
gnupg \
lsb-release                  -->prerequisites for docker 

 sudo mkdir -p /etc/apt/keyrings  --> Add Docker's GPG Keys
 curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg  -->Add Docker's GPG Keys
 
 echo \                                
 "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu \
 $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null                                             -->Use these command to set up the repository

Method 1 Installing Generally

 sudo apt-get update              -->update apt package index
 sudo apt-get install docker-ce docker-ce-cli containerd.io docker-compose-plugin         -->download latest docker

Method 2 Installing Specific Version

 sudo apt-cache madison docker-ce  --> searching for latest versions available for your ubuntu version

The below image lists the versions of docker available

image

   sudo apt-get install docker-ce=<VERSION_STRING> docker-ce-cli=<VERSION_STRING> containerd.io docker-compose-plugin  

If for example <VERSION_STRING>= 5:20.10.163-0ubuntu-jammy then,

   sudo apt-get install docker-ce=5:20.10.16~3-0~ubuntu-jammy docker-ce-cli=5:20.10.16~3-0~ubuntu-jammy containerd.io docker-compose-plugin

To ensure docker runs, run the below command

   sudo docker run hello-world         

Commands for downloading OPENLANE and PDKS of the latest stable version

This is just around 2.3 GB as you already have all the prerequisites. We can install this version in home directory or in Desktop or any directory of your choice. These below commands has been done in /Desktop directory

git clone https://github.com/The-OpenROAD-Project/openlane.git
cd OpenLane/
cd docker
sudo make                      ->  installs OpenLane  docker image 

If you get any fatal repository warning add these commands but your username could be different to the below commands

Note: badboy07 was the username used here so put your username instead.

sudo git config --global --add safe.directory /home/**badboy07**/Desktop/OpenLane
cd ..
ls
export PDK_ROOT=/home/badboy07/Desktop/OpenLane/pdks
sudo make pdk   ->installs skywater_pdks & open_pdks

For normal testing of spm design

sudo make test  ->initial testing of test design ie spm

Note: The below screenshots may vary depending on OpenLane versions downloaded using above commands.

image

image

image

sudo make mount    ->if permission denied

image

If successful you’ll get something similar to the one shown in the above image

Existing Design in Openlane Design Directory

PicoRV32 is the test design, which is a CPU core which implements the RISC-V RV32IMC Instruction Set. 1. Configuration files As seen in the above images we have used these configuration commands as given below.

 ./flow.tcl -design picorv32a   ->This command runs the entire OpenLane flow from preparation of design to generating GDSII)

Or we can follow the flow from OpenLane Interactive flow for Custom Design SERV

For details of SERV you can refer to the below links

https://github.com/olofk/serv/tree/v1.0/rtl https://serv.readthedocs.io/en/latest/

Note: instead of picorv32a you can use your design instead

Logic Synthesis Tool Flow for Custom Design SERV

image

The above image shows the flow of Yosys. Yosys takes RTL code and .lib files as input and netlist as output. Netlist is the standard cell representation of the design.

Yosys flow

read design
read_verilog serv_rf_top.v

elaborate design hierarchy

hierarchy -check -top serv_rf_top

the high-level stuff proc;

opt
fsm; opt;
memory; opt

mapping to internal cell library

techmap; op

mapping flip-flops to mycells.lib

dfflibmap -liberty home/badboy07/Desktop/vsdflow/work/tools/openlane_w orking_dir/pdks/open_pdks/sky130/sky130A/libs.ref/sky130_fd_sc_hs/lib/sky130_fd_sc_hs ff_100C_1v95.lib

mapping logic to mycells.lib

 abc -liberty home/badboy07/Desktop/vsdflow/work/tools/openlane_w orking_dir/pdks/open_pdks/sky130/sky130A/libs.ref/sky1 30_fd_sc_hs/lib/ sky130_fd_sc_hs ff_100C_1v95.lib

cleanup

 clean

write synthesized design

write_verilog serv_rf_top.synthesis

OpenLane automated flow for Custom Design SERV

./flow.tcl -design serv_rf_top -init_design_config

The above command flow.tcl has commands for running OpenLane flow so here we run the configuration flow Then we need to edit required variable in config.tcl

./flow.tcl -design serv_rf_top

This command runs the entire OpenLane flow from preparation of design to generating GDSII.

OpenLane Interactive flow for Custom Design SERV

./flow.tcl -interactive

This command runs OpenLane in interactive flow

Running the commands in interactive flow

package require openlane 0.9

This command checks the version of OpenLane required for the flow

prep -design serv_rf_top -tag serv_interactive

Preparing a design called serv_rf_top with tag for naming the current run.

run_synthesis

This command runs the synthesis right from Yosys till OpenSTA.

Conversion of RTL design to a circuit out of components from Standard cell library (SCL).

run_floorplan

This command performs the Floor planning and Power Distribution network(PDN) of the design.

Chip Floorplanning - Patitioning the chip die between different system blocks and placing the I/O pads

image

The above image describes the Chip Floorplanning

Macro Floorplanning - We define the macro dimensions, pin locations and row definitions.

image

Power Planning - Power network is constructed typically by multiple VDD and GND pins. the Power pins are all connected through power rings, vertical and horizontal metal straps. Power rings- Power ring is designed around the core. Power rings contains both VDD and VSS rings. After the ring is placed a power is designed such that power reaches all the cells easily.

image

This diagram shows the power planning components.

These parallel structures reduce resistance. To address electromagnetism the power distribution network uses upper metal layers as they are thicker than lower metal layers

run_placement

This command perform global placement and detailed placement of cells of the design.

image

Placing the cell on the floorplan rows aligned with sites. Connected cells should be placed close to each other to reduce the interconnect delay. It is done in two steps ie Global and Detailed Placement. In global placement , the approximate locations for cells is decided by placing cells in global bins. In detailed placement, cells are Placed without over lapping.

run_cts

Creating a clock distribution network :

Delivering clock to all sequential elements. • With Minimum skew • In Good shape • A tree (H,X etc)

run_routing

Implements interconnects using available metal layers. Metal tracks form a routing grid. Routing uses Divide and Conquer method. There are two types of Routing ie -Global routing: Generates routing guides -Detailed routing: Uses routing guides to implement actual wiring.

image

run_magic

This command generates Layout

run_magic_drc

This command performs DRC check on the layout.

run_klayout

This command creates backup layout

run_klayout_drc

Running DRC on layout generated from Klayout

run_klayout_gds_xor

This command is for generating GDS2 of our design with XOR design

run_lvs

This command checks for layout vs schematic violations

Layout Versus Schematic (LVS) checking compares the extracted netlist from the layout to the original schematic netlist to determine if they match. The comparison check is considered clean if all the devices and nets of the schematic match the devices and the nets of the layout.

run_lef_cvc

This command is used for Circuit Validity Checker on the output spice. Voltage aware ERC checker for CDL netlists.

run_antenna_check

This command is used for checking Antenna violations. Long metal lines and Vias introduce antenna violations. The antenna rule specifies the maximum tolerance for the ratio of a metal line area to the area of connected gates. VLSI process starts from the substrate, device layer and then metal layers.

Layout Generation by Magic Tool for SERV

Post Floorplanning

The below command is for generating layout after Floorplanning.

image

Post Placement The below command is for viewing layout after placement. All the images after the below command are from what was generated during Placement.

image

Post CTS The below command is for viewing layout after CTS. All the images after the below command are from what was generated during CTS.

image

Post Routing The below command is for viewing layout after routing. All the images after the below command are from what was generated during Routing.

image

Final GDSII layout for SERV design The below command is for opening the GDS file created.

image

image

This is how a successful flow of OpenLane flow will look like.

For further detailed explanation you can feel free to check this pdf

Advance_VLSI_Lab_OpenLane_RTL_GDSII_flow_final.pdf

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