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# Tutorial: Implementing a Macro for [Caravel](https://caravel-harness.readthedocs.io/en/latest/)
```{admonition} Note
:class: seealso
If you do not have prior experience with OpenLane, please make sure to go
through the [Getting Started: Newcomers](../../getting_started/newcomers/index.md) tutorial first.
```
AES stands for Advanced Encryption Standard which is a symmetric encryption
algorithm widely used across the globe to secure data. It operates on blocks of
data using keys of 128, 192, or 256 bits to encrypt and decrypt information,
providing a high level of security and efficiency for electronic data
protection. In this tutorial, we are going to harden an `AES` core and have it
as a
[Caravel User Project](https://caravel-user-project.readthedocs.io/en/latest/)
macro to serve as an accelerator for the chip
[Caravel](https://caravel-harness.readthedocs.io/en/latest/).
```{admonition} About Caravel
:class: seealso
The Efabless Caravel chip is a ready-to-use test harness for creating designs
with the Google/Skywater 130nm Open PDK. The Caravel harness comprises of base
functions supporting IO, power, and configuration as well as drop-in modules for
a management SoC core, and an approximately 3000um x 3600um open project area
for the placement of user IP blocks.
See [Caravel's documentation](https://caravel-harness.readthedocs.io/en/latest/)
for more information.
```
## Creating your own project repository
1. Start by creating a new repository from the Caravel user project OpenLane 2
[template](https://github.com/efabless/caravel_user_project_ol2/generate).
Let's call it `caravel_aes_accelerator`.
1. Open a terminal and clone your repository as follows:
```console
$ git clone git@github.com:<github_user_name>/caravel_aes_accelerator.git ~/caravel_aes_accelerator
```
______________________________________________________________________
## RTL integration
We begin by using the open-source RTLs for AES by
[Joachim Strömbergson](https://github.com/secworks) and adding a Wishbone bus
wrapper for Caravel. Since the RTL from secworks provides a generic memory
interface, we only need to add the `ack`, `write_enable`, and `read_enable`
logic to the Wishbone wrapper.
1. Clone the `secworks/aes` Git repository
```console
$ git clone git@github.com:secworks/aes.git ~/secworks_aes
```
1. Create the Verilog file
`~/caravel_aes_accelerator/verilog/rtl/aes_wb_wrapper.v` and add the Wishbone
wrapper to the RTL:
````{dropdown} aes_wb_wrapper.v
```{literalinclude} ./aes_wb_wrapper.v
```
````
1. Instantiate the `aes_wb_wrapper` in the `user_project_wrapper` Verilog file
under `~/caravel_aes_accelerator/verilog/rtl`
````{dropdown} user_project_wrapper.v
```{literalinclude} ./user_project_wrapper.v
```
````
```{seealso}
Check out
[Caravel User Project's documentation on Verilog Integration](https://caravel-user-project.readthedocs.io/en/latest/#verilog-integration)
for information about the changes that were done to the RTL.
```
(configuration-user-project-wrapper)=
______________________________________________________________________
## Hardening strategies
There are 3 options for implementing a Caravel User Project design using
OpenLane:
1. `Macro-First Hardening`: Harden the user macro(s) initially and incorporate
them into the user project wrapper without top-level standard cells. Ideal
for smaller designs, as this approach significantly reduces Placement and
Routing (PnR) and signoff time.
1. `Full-Wrapper Flattening`: Merge the user macro(s) with the
user_project_wrapper, covering the entire wrapper area. While this method
demands more time and iterations for PnR and signoff, it ultimately enhances
performance, making it suitable for designs requiring the full wrapper area.
1. `Top-Level Integration`: Place the user macro(s) within the wrapper alongside
standard cells at the top level. This method is typically chosen to introduce
buffering at the top level, fitting scenarios where such an approach is
necessary.
```{seealso}
See the
[Caravel Integration & Power Routing document](https://docs.google.com/document/d/1pf-wbpgjeNEM-1TcvX2OJTkHjqH_C9p-LURCASS0Zo8)
for more information about these options.
```
______________________________________________________________________
## 1. Macro-First Hardening strategy
We will start with the first hardening option. That entails:
1. Hardening the `aes` core with the Wishbone wrapper as a macro
1. Hardening the `user_project_wrapper` with the `aes` macro hardened in the
previous step
…the latter of which, will be integrated into the Caravel harness.
______________________________________________________________________
### AES Wishbone Wrapper Hardening
#### Configuration
1. Create a design directory to add our source files to:
```console
$ mkdir -p ~/caravel_aes_accelerator/openlane/aes_wb_wrapper
```
1. Create the file
`~/caravel_aes_accelerator/openlane/aes_wb_wrapper/config.json` and add the
following simple configuration to it
```json
{
"DESIGN_NAME": "aes_wb_wrapper",
"FP_PDN_MULTILAYER": false,
"CLOCK_PORT": "wb_clk_i",
"CLOCK_PERIOD": 25,
"VERILOG_FILES": [
"dir::../../../secworks_aes/src/rtl/aes.v",
"dir::../../../secworks_aes/src/rtl/aes_core.v",
"dir::../../../secworks_aes/src/rtl/aes_decipher_block.v",
"dir::../../../secworks_aes/src/rtl/aes_encipher_block.v",
"dir::../../../secworks_aes/src/rtl/aes_inv_sbox.v",
"dir::../../../secworks_aes/src/rtl/aes_key_mem.v",
"dir::../../../secworks_aes/src/rtl/aes_sbox.v",
"dir::../../verilog/rtl/aes_wb_wrapper.v"
],
"FP_CORE_UTIL": 40
}
```
This is a basic configuration file which has only these variables:
* {var}`::DESIGN_NAME`: the name of the design, which is equal to the name of
the top module in Verilog.
* {var}`::CLOCK_PORT`: the name of the clock port in said top module.
* {var}`::CLOCK_PERIOD`: the period of the primary clock port in nanoseconds,
used to determine the chip frequency. Generally, the lowest you can get away
with is the best.
{math}`\text{f} = 1 / (\texttt{CLOCK_PERIOD}ns) = 1 / (25\text{ns}) = 25 \text{MHz}`
* {var}`Yosys.Synthesis::VERILOG_FILES`: List of input Verilog files.
* {var}`OpenROAD.Floorplan::FP_CORE_UTIL`: The core utilization. Typical values
for the core utilization range from 25% to 60%. 40% is a good starting value -
we can adjust it later if we need to (i.e. one of the tools complains.)
* {var}`OpenROAD.GeneratePDN::FP_PDN_MULTILAYER`: We set this to `false` as we
are hardening a chip for integration into Caravel. You may review
{doc}`/usage/pdn` for more information on this.
______________________________________________________________________
#### Running the flow
To harden macros with OpenLane, we use the default flow, {flow}`Classic`.
Let's try running the flow from OpenLane:
```console
[nix-shell:~]$ openlane ~/caravel_aes_accelerator/openlane/aes_wb_wrapper/config.json
```
````{tip}
Double-checking: are you inside a `nix-shell`? Your terminal prompt
should look like this:
```console
[nix-shell:~]$
```
If not, enter the following command in your terminal:
```console
$ nix-shell --pure ~/openlane2/shell.nix
```
````
The flow will finish successfully in ~20 minutes (depending on the speed of your
computer) and we will see:
```console
Flow complete.
```
______________________________________________________________________
#### Viewing the layout
To open the final {term}`GDSII` layout run this command:
```console
[nix-shell:~/openlane2]$ openlane --last-run --flow openinklayout ~/caravel_aes_accelerator/openlane/aes_wb_wrapper/config.json
```
This opens {term}`KLayout` and you should be able to see the following:
```{figure} ./aes-1-gds.webp
:align: center
Final layout of aes_wb_wrapper
```
```{tip}
You can control the visible layers in KLayout by double-clicking on the
layers you want to hide/unhide. In this figure, the layers `areaid.lowTapDensity`
and `areaid.standardc` were hidden to view the layout more clearly.
```
______________________________________________________________________
#### Checking the reports
You’ll find that a run directory (named something like
`runs/RUN_2024-02-05_16-46-01`) was created when you ran OpenLane. Under this
folder, the logs, reports, and physical views will be located. It is always a
good idea to review all logs and reports for all the steps in your run. However,
in this guide, we will only review the main signoff reports from a couple of
steps.
______________________________________________________________________
```{tip}
The names of step directories are constructed as follows:
`{ordinal}-{step_id_slugified}`
…where `ordinal` is a counter showing in what order a step was run, and
`step_id_slugified` is, broadly, the step's ID converted to lowercase and
dots replaced with dashes.
```
(caravel-openroad-checkantennas-with-fixes)=
##### `OpenROAD.CheckAntennas`
There are 2 {step}`OpenROAD.CheckAntennas` steps. One after
{step}`OpenROAD.GlobalRouting` and the other after
{step}`OpenROAD.DetailedRouting`. We are interested in the one after
{step}`OpenROAD.DetailedRouting` as this is the final antenna check.
```{seealso}
For more information about antenna violations, check
[this section again in the newcomers' guide](../../getting_started/newcomers/index.md#antenna-check).
```
Inside the step directory of {step}`OpenROAD.CheckAntennas`, there is a
`reports` directory that contains two files; the full antenna check report from
`OpenROAD` and a summary table of antenna violations:
```
┏━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━┓
┃ Partial/Required ┃ Required ┃ Partial ┃ Net ┃ Pin ┃ Layer ┃
┡━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━┩
│ 8.43 │ 400.00 │ 3373.21 │ net337 │ _19592_/A1 │ met3 │
│ 4.06 │ 400.00 │ 1624.33 │ _06003_ │ _20370_/A_N │ met1 │
│ 3.84 │ 400.00 │ 1534.48 │ net40 │ _19524_/A0 │ met3 │
│ 3.68 │ 400.00 │ 1471.09 │ _09365_ │ wire82/A │ met3 │
│ 3.51 │ 400.00 │ 1402.54 │ aes.core.dec_block.block_w0_reg[12\] │ _35456_/A0 │ met3 │
│ 3.33 │ 400.00 │ 1330.55 │ _13932_ │ _34198_/A │ met3 │
│ 3.33 │ 400.00 │ 1330.55 │ _13932_ │ _34199_/A1 │ met3 │
⋮
```
As seen in the report, there are around 110 antenna violations some of which
have high ratios up to 8. It is recommended to fix all antenna violations with
ratios higher than 3 and the higher the ratio `Partial/Required` the more
severely it might affect the chip. In order to fix those antenna violations, one
or more of the following solutions can be applied:
1. Increase the number of iterations for antenna repair using
{var}`openroad.repairantennas::GRT_ANTENNA_ITERS`. The default value is `3`.
We can increase it to `10` by adding this to our `config.json` file.
```json
"GRT_ANTENNA_ITERS": 10,
```
2. Increase the margin for antenna repair using
{var}`openroad.repairantennas::GRT_ANTENNA_MARGIN`. The default value is
`10`. We can increase it to `15`.
```json
"GRT_ANTENNA_MARGIN": 15,
```
3. Enable heuristic diode insertion using
{var}`Classic::RUN_HEURISTIC_DIODE_INSERTION`:
```json
"RUN_HEURISTIC_DIODE_INSERTION": true,
```
4. Constrain the max wire length (in µm) using
{var}`OpenROAD.RepairDesign::DESIGN_REPAIR_MAX_WIRE_LENGTH`.
```json
"DESIGN_REPAIR_MAX_WIRE_LENGTH": 800,
```
5. Optimize the global placement for minimum wire length using
{var}`OpenROAD.GlobalPlacement::PL_WIRE_LENGTH_COEF`.
```json
"PL_WIRE_LENGTH_COEF": 0.05,
```
______________________________________________________________________
(caravel-openroad-stapostpnr-with-fixes)=
##### `OpenROAD.STAPostPNR`
Under `xx-openroad-stapostpnr` there should be a file called `summary.rpt`:
```text
┏━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┓
┃ ┃ Hold Worst ┃ Reg to Reg ┃ ┃ Hold ┃ of which Reg ┃ Setup Worst ┃ Reg to Reg ┃ ┃ Setup ┃ of which Reg ┃ Max Cap ┃ Max Slew ┃
┃ Corner/Group ┃ Slack ┃ Paths ┃ Hold TNS ┃ Violations ┃ to Reg ┃ Slack ┃ Paths ┃ Setup TNS ┃ Violations ┃ to Reg ┃ Violations ┃ Violations ┃
┡━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━┩
│ Overall │ 0.1045 │ 0.1045 │ 0.0000 │ 0 │ 0 │ 6.2448 │ 6.2448 │ 0.0000 │ 0 │ 0 │ 257 │ 1554 │
│ nom_tt_025C… │ 0.3111 │ 0.3111 │ 0.0000 │ 0 │ 0 │ 12.5817 │ 15.9480 │ 0.0000 │ 0 │ 0 │ 179 │ 126 │
│ nom_ss_100C… │ 0.8728 │ 0.8728 │ 0.0000 │ 0 │ 0 │ 6.6277 │ 6.6277 │ 0.0000 │ 0 │ 0 │ 191 │ 1227 │
│ nom_ff_n40C… │ 0.1058 │ 0.1058 │ 0.0000 │ 0 │ 0 │ 13.4537 │ 19.3029 │ 0.0000 │ 0 │ 0 │ 181 │ 26 │
│ min_tt_025C… │ 0.3098 │ 0.3098 │ 0.0000 │ 0 │ 0 │ 12.6013 │ 16.1989 │ 0.0000 │ 0 │ 0 │ 119 │ 76 │
│ min_ss_100C… │ 0.8712 │ 0.8712 │ 0.0000 │ 0 │ 0 │ 7.0939 │ 7.0939 │ 0.0000 │ 0 │ 0 │ 122 │ 849 │
│ min_ff_n40C… │ 0.1045 │ 0.1045 │ 0.0000 │ 0 │ 0 │ 13.4665 │ 19.4702 │ 0.0000 │ 0 │ 0 │ 119 │ 0 │
│ max_tt_025C… │ 0.3131 │ 0.3131 │ 0.0000 │ 0 │ 0 │ 12.5529 │ 15.7241 │ 0.0000 │ 0 │ 0 │ 239 │ 183 │
│ max_ss_100C… │ 0.8762 │ 0.8762 │ 0.0000 │ 0 │ 0 │ 6.2448 │ 6.2448 │ 0.0000 │ 0 │ 0 │ 257 │ 1554 │
│ max_ff_n40C… │ 0.1073 │ 0.1073 │ 0.0000 │ 0 │ 0 │ 13.4347 │ 19.1522 │ 0.0000 │ 0 │ 0 │ 239 │ 36 │
└──────────────┴──────────────┴──────────────┴──────────┴──────────────┴──────────────┴──────────────┴──────────────┴───────────┴─────────────┴──────────────┴─────────────┴──────────────┘
```
As seen in the report, there are no hold or setup violations. There are only Max
Cap and Max Slew violations. To see the violations:
1. Open the report `checks` under `xx-openroad-stapostpnr/max_ss_100C_1v60`
since this corner has the highest number of Max Cap and Max Slew violations.
1. Search for `max slew` and you will find the violations listed as follows:
```text
Pin Limit Slew Slack
------------------------------------------------------------------------
_31022_/B1 0.750000 2.000525 -1.250525 (VIOLATED)
_34084_/A2 0.750000 1.999526 -1.249526 (VIOLATED)
_31021_/Y 0.750000 1.998896 -1.248896 (VIOLATED)
_29818_/B 0.750000 1.815682 -1.065682 (VIOLATED)
_32128_/A2 0.750000 1.815665 -1.065665 (VIOLATED)
_30041_/A 0.750000 1.815654 -1.065654 (VIOLATED)
_29817_/Y 0.750000 1.814748 -1.064748 (VIOLATED)
wire109/A 0.750000 1.773218 -1.023218 (VIOLATED)
_21294_/Y 0.750000 1.773215 -1.023215 (VIOLATED)
wire91/A 0.750000 1.683392 -0.933392 (VIOLATED)
⋮
```
In order to fix the maximum slew/cap violations, **one or more** of the
following solutions can be applied:
1. Relax the {var}`::MAX_TRANSITION_CONSTRAINT` to 1.5ns as this is the
constraint in the sky130 lib files
```json
"MAX_TRANSITION_CONSTRAINT": 1.5,
```
2. Increase the slew/cap repair margins using
{var}`OpenROAD.RepairDesign::DESIGN_REPAIR_MAX_SLEW_PCT` and
{var}`OpenROAD.RepairDesign::DESIGN_REPAIR_MAX_CAP_PCT`. The default value is
20%. We can increase it to 30%:
```json
"DESIGN_REPAIR_MAX_SLEW_PCT": 30,
"DESIGN_REPAIR_MAX_CAP_PCT": 30,
```
3. Change the default timing corner using {var}`::DEFAULT_CORNER` for the corner
with the most violations which will be `max_ss_100C_1v60` in our case:
```json
"DEFAULT_CORNER": "max_ss_100C_1v60",
```
4. Enable post-global routing design optimizations using
{var}`Classic::RUN_POST_GRT_DESIGN_REPAIR`:
```json
"RUN_POST_GRT_DESIGN_REPAIR": true,
```
5. Most importantly, it is recommended to use design-specific {term}`SDC` files
for your design using the {var}`OpenROAD.CheckSDCFiles::PNR_SDC_FILE` and
{var}`OpenROAD.CheckSDCFiles::SIGNOFF_SDC_FILE` variables.
```json
"PNR_SDC_FILE": "dir::cons.sdc",
"SIGNOFF_SDC_FILE": "dir::cons.sdc",
```
______________________________________________________________________
##### `Magic.DRC`
Under the directory `xx-magic-drc`, you will find a file named `reports/drc.rpt`
that summarizes the DRC violations reported by Magic. The design is DRC clean so
the report will look like this:
```text
aes_wb_wrapper
----------------------------------------
[INFO] COUNT: 0
[INFO] Should be divided by 3 or 4
```
______________________________________________________________________
##### `KLayout.DRC`
Under the directory `xx-klayout-drc`, you will find a file named
`violations.json` that summarizes the DRC violations reported by KLayout. The
design is DRC clean so the report will look like this with `"total": 0` at the
end:
```text
{
⋮
"total": 0
}
```
______________________________________________________________________
##### `Netgen.LVS`
Under the directory `xx-netgen-lvs`, you will find a file named `lvs.rpt` that
summarizes the LVS violations reported by netgen. The design is LVS clean so the
last part of the report will look like this:
```text
Cell pin lists are equivalent.
Device classes aes_wb_wrapper and aes_wb_wrapper are equivalent.
Final result: Circuits match uniquely.
```
______________________________________________________________________
#### Re-running the flow with a modified configuration
To fix the previous issues in the implementation, the following was added to the
config file:
```json
"GRT_ANTENNA_ITERS": 10,
"RUN_HEURISTIC_DIODE_INSERTION": true,
"HEURISTIC_ANTENNA_THRESHOLD": 200,
"DESIGN_REPAIR_MAX_WIRE_LENGTH": 800,
"DEFAULT_CORNER": "max_ss_100C_1v60",
"RUN_POST_GRT_DESIGN_REPAIR": true,
"PNR_SDC_FILE": "dir::pnr.sdc",
"SIGNOFF_SDC_FILE": "dir::signoff.sdc"
```
…and the following 2 constraints files `pnr.sdc` and `signoff.sdc` were created
at `~/caravel_aes_accelerator/openlane/aes_wb_wrapper/`:
````{dropdown} pnr.sdc
```tcl
#------------------------------------------#
# Design Constraints
#------------------------------------------#
# Clock network
set clk_input wb_clk_i
create_clock [get_ports $clk_input] -name clk -period 25
puts "\[INFO\]: Creating clock {clk} for port $clk_input with period: 25"
# Clock non-idealities
set_propagated_clock [get_clocks {clk}]
set_clock_uncertainty 0.12 [get_clocks {clk}]
puts "\[INFO\]: Setting clock uncertainty to: 0.12"
# Maximum transition time for the design nets
set_max_transition 0.75 [current_design]
puts "\[INFO\]: Setting maximum transition to: 0.75"
# Maximum fanout
set_max_fanout 16 [current_design]
puts "\[INFO\]: Setting maximum fanout to: 16"
# Timing paths delays derate
set_timing_derate -early [expr {1-0.07}]
set_timing_derate -late [expr {1+0.07}]
# Multicycle paths
set_multicycle_path -setup 2 -through [get_ports {wbs_ack_o}]
set_multicycle_path -hold 1 -through [get_ports {wbs_ack_o}]
set_multicycle_path -setup 2 -through [get_ports {wbs_cyc_i}]
set_multicycle_path -hold 1 -through [get_ports {wbs_cyc_i}]
set_multicycle_path -setup 2 -through [get_ports {wbs_stb_i}]
set_multicycle_path -hold 1 -through [get_ports {wbs_stb_i}]
#------------------------------------------#
# Retrieved Constraints then modified
#------------------------------------------#
# Clock source latency
set usr_clk_max_latency 4.57
set usr_clk_min_latency 4.11
set clk_max_latency 5.70
set clk_min_latency 4.40
set_clock_latency -source -max $clk_max_latency [get_clocks {clk}]
set_clock_latency -source -min $clk_min_latency [get_clocks {clk}]
puts "\[INFO\]: Setting clock latency range: $clk_min_latency : $clk_max_latency"
# Clock input Transition
set_input_transition 0.61 [get_ports $clk_input]
# Input delays
set_input_delay -max 3.27 -clock [get_clocks {clk}] [get_ports {wbs_sel_i[*]}]
set_input_delay -max 3.84 -clock [get_clocks {clk}] [get_ports {wbs_we_i}]
set_input_delay -max 3.99 -clock [get_clocks {clk}] [get_ports {wbs_adr_i[*]}]
set_input_delay -max 4.23 -clock [get_clocks {clk}] [get_ports {wbs_stb_i}]
set_input_delay -max 4.71 -clock [get_clocks {clk}] [get_ports {wbs_dat_i[*]}]
set_input_delay -max 4.84 -clock [get_clocks {clk}] [get_ports {wbs_cyc_i}]
set_input_delay -min 0.50 -clock [get_clocks {clk}] [get_ports {wbs_adr_i[*]}]
set_input_delay -min 0.94 -clock [get_clocks {clk}] [get_ports {wbs_dat_i[*]}]
set_input_delay -min 1.09 -clock [get_clocks {clk}] [get_ports {wbs_sel_i[*]}]
set_input_delay -min 1.55 -clock [get_clocks {clk}] [get_ports {wbs_we_i}]
set_input_delay -min 1.20 -clock [get_clocks {clk}] [get_ports {wbs_cyc_i}]
set_input_delay -min 1.46 -clock [get_clocks {clk}] [get_ports {wbs_stb_i}]
# Reset input delay
set_input_delay [expr 25 * 0.5] -clock [get_clocks {clk}] [get_ports {wb_rst_i}]
# Input Transition
set_input_transition -max 0.14 [get_ports {wbs_we_i}]
set_input_transition -max 0.15 [get_ports {wbs_stb_i}]
set_input_transition -max 0.17 [get_ports {wbs_cyc_i}]
set_input_transition -max 0.18 [get_ports {wbs_sel_i[*]}]
set_input_transition -max 0.84 [get_ports {wbs_dat_i[*]}]
set_input_transition -max 0.92 [get_ports {wbs_adr_i[*]}]
set_input_transition -min 0.07 [get_ports {wbs_adr_i[*]}]
set_input_transition -min 0.07 [get_ports {wbs_dat_i[*]}]
set_input_transition -min 0.09 [get_ports {wbs_cyc_i}]
set_input_transition -min 0.09 [get_ports {wbs_sel_i[*]}]
set_input_transition -min 0.09 [get_ports {wbs_we_i}]
set_input_transition -min 0.15 [get_ports {wbs_stb_i}]
# Output delays
set_output_delay -max 3.72 -clock [get_clocks {clk}] [get_ports {wbs_dat_o[*]}]
set_output_delay -max 8.51 -clock [get_clocks {clk}] [get_ports {wbs_ack_o}]
set_output_delay -min 1.03 -clock [get_clocks {clk}] [get_ports {wbs_dat_o[*]}]
set_output_delay -min 1.27 -clock [get_clocks {clk}] [get_ports {wbs_ack_o}]
# Output loads
set_load 0.19 [all_outputs]
```
````
````{dropdown} signoff.sdc
```tcl
#------------------------------------------#
# Design Constraints
#------------------------------------------#
# Clock network
set clk_input wb_clk_i
create_clock [get_ports $clk_input] -name clk -period 25
puts "\[INFO\]: Creating clock {clk} for port $clk_input with period: 25"
# Clock non-idealities
set_propagated_clock [get_clocks {clk}]
set_clock_uncertainty 0.1 [get_clocks {clk}]
puts "\[INFO\]: Setting clock uncertainty to: 0.1"
# Maximum transition time for the design nets
set_max_transition 1.5 [current_design]
puts "\[INFO\]: Setting maximum transition to: 1.5"
# Maximum fanout
set_max_fanout 16 [current_design]
puts "\[INFO\]: Setting maximum fanout to: 16"
# Timing paths delays derate
set_timing_derate -early [expr {1-0.05}]
set_timing_derate -late [expr {1+0.05}]
puts "\[INFO\]: Setting timing derate to: [expr {0.05 * 100}] %"
# Multicycle paths
set_multicycle_path -setup 2 -through [get_ports {wbs_ack_o}]
set_multicycle_path -hold 1 -through [get_ports {wbs_ack_o}]
set_multicycle_path -setup 2 -through [get_ports {wbs_cyc_i}]
set_multicycle_path -hold 1 -through [get_ports {wbs_cyc_i}]
set_multicycle_path -setup 2 -through [get_ports {wbs_stb_i}]
set_multicycle_path -hold 1 -through [get_ports {wbs_stb_i}]
#------------------------------------------#
# Retrieved Constraints
#------------------------------------------#
# Clock source latency
set usr_clk_max_latency 4.57
set usr_clk_min_latency 4.11
set clk_max_latency 5.57
set clk_min_latency 4.65
set_clock_latency -source -max $clk_max_latency [get_clocks {clk}]
set_clock_latency -source -min $clk_min_latency [get_clocks {clk}]
puts "\[INFO\]: Setting clock latency range: $clk_min_latency : $clk_max_latency"
# Clock input Transition
set_input_transition 0.61 [get_ports $clk_input]
# Input delays
set_input_delay -max 3.17 -clock [get_clocks {clk}] [get_ports {wbs_sel_i[*]}]
set_input_delay -max 3.74 -clock [get_clocks {clk}] [get_ports {wbs_we_i}]
set_input_delay -max 3.89 -clock [get_clocks {clk}] [get_ports {wbs_adr_i[*]}]
set_input_delay -max 4.13 -clock [get_clocks {clk}] [get_ports {wbs_stb_i}]
set_input_delay -max 4.61 -clock [get_clocks {clk}] [get_ports {wbs_dat_i[*]}]
set_input_delay -max 4.74 -clock [get_clocks {clk}] [get_ports {wbs_cyc_i}]
set_input_delay -min 0.79 -clock [get_clocks {clk}] [get_ports {wbs_adr_i[*]}]
set_input_delay -min 1.04 -clock [get_clocks {clk}] [get_ports {wbs_dat_i[*]}]
set_input_delay -min 1.19 -clock [get_clocks {clk}] [get_ports {wbs_sel_i[*]}]
set_input_delay -min 1.65 -clock [get_clocks {clk}] [get_ports {wbs_we_i}]
set_input_delay -min 1.69 -clock [get_clocks {clk}] [get_ports {wbs_cyc_i}]
set_input_delay -min 1.86 -clock [get_clocks {clk}] [get_ports {wbs_stb_i}]
# Reset input delay
set_input_delay [expr 25 * 0.5] -clock [get_clocks {clk}] [get_ports {wb_rst_i}]
# Input Transition
set_input_transition -max 0.14 [get_ports {wbs_we_i}]
set_input_transition -max 0.15 [get_ports {wbs_stb_i}]
set_input_transition -max 0.17 [get_ports {wbs_cyc_i}]
set_input_transition -max 0.18 [get_ports {wbs_sel_i[*]}]
set_input_transition -max 0.84 [get_ports {wbs_dat_i[*]}]
set_input_transition -max 0.92 [get_ports {wbs_adr_i[*]}]
set_input_transition -min 0.07 [get_ports {wbs_adr_i[*]}]
set_input_transition -min 0.07 [get_ports {wbs_dat_i[*]}]
set_input_transition -min 0.09 [get_ports {wbs_cyc_i}]
set_input_transition -min 0.09 [get_ports {wbs_sel_i[*]}]
set_input_transition -min 0.09 [get_ports {wbs_we_i}]
set_input_transition -min 0.15 [get_ports {wbs_stb_i}]
# Output delays
set_output_delay -max 3.62 -clock [get_clocks {clk}] [get_ports {wbs_dat_o[*]}]
set_output_delay -max 8.41 -clock [get_clocks {clk}] [get_ports {wbs_ack_o}]
set_output_delay -min 1.13 -clock [get_clocks {clk}] [get_ports {wbs_dat_o[*]}]
set_output_delay -min 1.37 -clock [get_clocks {clk}] [get_ports {wbs_ack_o}]
# Output loads
set_load 0.19 [all_outputs]
```
````
The `Design Constraints` part has to do with the design itself. The
`Retrieved Constraints` part is retrieved from the Caravel chip boundary
constraints with the `user_project_wrapper`. These constraints can be found
[here](https://github.com/efabless/caravel_user_project_ol2/blob/a9dd629af92482842ddcaba8d95c298b41c1895b/openlane/user_project_wrapper/base_user_project_wrapper.sdc#L64).
The PnR constraints file has more aggressive constraints than the signoff one,
this is done to accommodate the gap between the optimization tool estimation of
parasitics and the final extractions on the layout.
```{seealso}
For the most comprehensive guide available on making SDC files, we recommend this
excellent book by Sridhar Gangadharan and Sanjay Churiwala:
[Constraining Designs for Synthesis and Timing Analysis: A Practical Guide to Synopsys Design Constraints (SDC)](https://link.springer.com/book/10.1007/978-1-4614-3269-2)
```
So, the final `config.json` is as follows:
```json
{
"DESIGN_NAME": "aes_wb_wrapper",
"FP_PDN_MULTILAYER": false,
"CLOCK_PORT": "wb_clk_i",
"CLOCK_PERIOD": 25,
"VERILOG_FILES": [
"dir::../../../secworks_aes/src/rtl/aes.v",
"dir::../../../secworks_aes/src/rtl/aes_core.v",
"dir::../../../secworks_aes/src/rtl/aes_decipher_block.v",
"dir::../../../secworks_aes/src/rtl/aes_encipher_block.v",
"dir::../../../secworks_aes/src/rtl/aes_inv_sbox.v",
"dir::../../../secworks_aes/src/rtl/aes_key_mem.v",
"dir::../../../secworks_aes/src/rtl/aes_sbox.v",
"dir::../../verilog/rtl/aes_wb_wrapper.v"
],
"FP_CORE_UTIL": 40,
"GRT_ANTENNA_ITERS": 10,
"RUN_HEURISTIC_DIODE_INSERTION": true,
"HEURISTIC_ANTENNA_THRESHOLD": 200,
"DESIGN_REPAIR_MAX_WIRE_LENGTH": 800,
"DEFAULT_CORNER": "max_ss_100C_1v60",
"RUN_POST_GRT_DESIGN_REPAIR": true,
"PNR_SDC_FILE": "dir::pnr.sdc",
"SIGNOFF_SDC_FILE": "dir::signoff.sdc"
}
```
Now let's try re-running the flow:
```console
[nix-shell:~/openlane2]$ openlane ~/caravel_aes_accelerator/openlane/aes_wb_wrapper/config.json
```
______________________________________________________________________
#### Re-checking the reports
Now, the antenna report under
`xx-openroad-checkantennas-1/reports/antenna_summary.rpt` has much less
violations:
```{note}
The number of antenna violations may vary wildly depending on the configuration
variables AND environment variables (such as the operating system) as the
detailed router is highly heuristic.
On macOS, around a dozen violations are returned.
```
```text
┏━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━┓
┃ Partial/Required ┃ Required ┃ Partial ┃ Net ┃ Pin ┃ Layer ┃
┡━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━┩
│ 1.24 │ 400.00 │ 495.45 │ _12832_ │ _27256_/B2 │ met3 │
│ 1.23 │ 400.00 │ 493.06 │ _13527_ │ _26076_/A2 │ met3 │
└──────────────────┴──────────┴─────────┴─────────┴────────────┴───────┘
```
Also, the STA report at `xx-openroad-stapostpnr/summary.rpt` should have no
issues:
```text
┏━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━┓
┃ ┃ Hold ┃ ┃ ┃ ┃ of which ┃ Setup ┃ ┃ ┃ ┃ of which ┃ ┃ ┃
┃ ┃ Worst ┃ Reg to ┃ ┃ Hold ┃ Reg to ┃ Worst ┃ Reg to ┃ ┃ Setup ┃ Reg to ┃ Max Cap ┃ Max Slew ┃
┃ Corner/G… ┃ Slack ┃ Reg Paths ┃ Hold TNS ┃ Violatio… ┃ Reg ┃ Slack ┃ Reg Paths ┃ Setup TNS ┃ Violatio… ┃ Reg ┃ Violatio… ┃ Violati… ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━┩
│ Overall │ 0.1601 │ 0.1601 │ 0.0000 │ 0 │ 0 │ 4.4661 │ 6.0628 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ nom_tt_0… │ 0.2973 │ 0.3282 │ 0.0000 │ 0 │ 0 │ 10.4185 │ 15.6935 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ nom_ss_1… │ 0.7765 │ 0.7803 │ 0.0000 │ 0 │ 0 │ 4.6415 │ 6.5571 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ nom_ff_n… │ 0.1650 │ 0.1650 │ 0.0000 │ 0 │ 0 │ 11.1307 │ 19.2289 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ min_tt_0… │ 0.3215 │ 0.3215 │ 0.0000 │ 0 │ 0 │ 10.5622 │ 15.9933 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ min_ss_1… │ 0.7678 │ 0.7678 │ 0.0000 │ 0 │ 0 │ 4.8466 │ 7.0670 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ min_ff_n… │ 0.1601 │ 0.1601 │ 0.0000 │ 0 │ 0 │ 11.1436 │ 19.4234 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ max_tt_0… │ 0.2648 │ 0.3330 │ 0.0000 │ 0 │ 0 │ 10.2510 │ 15.4043 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ max_ss_1… │ 0.7331 │ 0.7868 │ 0.0000 │ 0 │ 0 │ 4.4661 │ 6.0628 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ max_ff_n… │ 0.1656 │ 0.1656 │ 0.0000 │ 0 │ 0 │ 11.1023 │ 19.0289 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
└───────────┴───────────┴───────────┴──────────┴───────────┴───────────┴───────────┴───────────┴───────────┴───────────┴───────────┴───────────┴──────────┘
```
______________________________________________________________________
#### Saving the views
To save the views, run the following script with the following arguments in
order:
1. The directory of the project
1. The macro name
1. The successful run tag
```console
[nix-shell:~/openlane2]$ bash ~/caravel_aes_accelerator/openlane/copy_views.sh ~/caravel_aes_accelerator aes_wb_wrapper RUN_TAG
```
This will copy the physical views of the macro in the specified run to your
project folder.
______________________________________________________________________
### User Project Wrapper Hardening
#### Configuration
The User Project Wrapper is a macro inside the Caravel chip which will include
our design. To be able to use any design as a Caravel User Project, it has to
match the footprint that Caravel is expecting. Also, the top-level design
Caravel is expecting any Caravel User Project to have the IO pins at specific
locations and with specific dimensions. So, we need a fixed floorplan, fixed
I/Os pin shapes and locations, and fixed power rings. The fixed configuration
section can be found at the end of the configurations file
`openlane/user_project_wrapper/config.json`:
```json
"//": "Fixed configurations for Caravel. You should NOT edit this section",
"DESIGN_NAME": "user_project_wrapper",
"FP_SIZING": "absolute",
"DIE_AREA": [0, 0, 2920, 3520],
"FP_DEF_TEMPLATE": "dir::fixed_dont_change/user_project_wrapper.def",
"VDD_NETS": [
"vccd1",
"vccd2",
"vdda1",
"vdda2"
],
"GND_NETS": [
"vssd1",
"vssd2",
"vssa1",
"vssa2"
],
"FP_PDN_CORE_RING": 1,
"FP_PDN_CORE_RING_VWIDTH": 3.1,
"FP_PDN_CORE_RING_HWIDTH": 3.1,
"FP_PDN_CORE_RING_VOFFSET": 12.45,
"FP_PDN_CORE_RING_HOFFSET": 12.45,
"FP_PDN_CORE_RING_VSPACING": 1.7,
"FP_PDN_CORE_RING_HSPACING": 1.7,
"CLOCK_PORT": "wb_clk_i",
"SIGNOFF_SDC_FILE": "dir::signoff.sdc",
"MAGIC_DEF_LABELS": 0,
"CLOCK_PERIOD": 25,
"MAGIC_ZEROIZE_ORIGIN": 0
```
The rest of the configuration file can be edited. Now, We need the following
edits for the `openlane/user_project_wrapper/config.json` in order to integrate
our macro inside the `user_project_wrapper`:
1. Replace the `user_proj_example` in the `MACROS` variable with our macro.
First, we change the physical views to `aes_wb_wrapper`. Second, we can
modify the macro location to `[1500, 1500]` to be in the middle of the chip.
The new macro variable will be:
```json
"MACROS": {
"aes_wb_wrapper": {
"gds": [
"dir::../../gds/aes_wb_wrapper.gds"
],
"lef": [
"dir::../../lef/aes_wb_wrapper.lef"
],
"instances": {
"mprj": {
"location": [1500, 1500],
"orientation": "N"
}
},
"nl": [
"dir::../../verilog/gl/aes_wb_wrapper.v"
],
"spef": {
"min_*": [
"dir::../../spef/multicorner/aes_wb_wrapper.min.spef"
],
"nom_*": [
"dir::../../spef/multicorner/aes_wb_wrapper.nom.spef"
],
"max_*": [
"dir::../../spef/multicorner/aes_wb_wrapper.max.spef"
]
},
"lib": {
"*": "dir::../../lib/aes_wb_wrapper.lib"
}
}
},
```
2. Update the power pins in {var}`OpenROAD.GeneratePDN::PDN_MACRO_CONNECTIONS`
to the macro power pins
```json
"PDN_MACRO_CONNECTIONS": ["mprj vccd2 vssd2 VPWR VGND"],
```
```{admonition} Note
:class: seealso
If we have multiple macros, we can add more entries to the variable `MACROS`.
```
______________________________________________________________________
#### Running the flow
```console
[nix-shell:~/openlane2]$ openlane ~/caravel_aes_accelerator/openlane/user_project_wrapper/config.json
```
````{tip}
Double-checking: are you inside a `nix-shell`? Your terminal prompt should look
like this:
```console
[nix-shell:~/openlane2]$
```
If not, enter the following command in your terminal:
```console
$ nix-shell --pure ~/openlane2/shell.nix
```
````
The flow will finish successfully in ~7 minutes and we will see:
```console
Flow complete.
```
______________________________________________________________________
#### Viewing the layout
To open the final {term}`GDSII` layout run this command:
```console
[nix-shell:~/openlane2]$ openlane --last-run --flow openinklayout ~/caravel_aes_accelerator/openlane/user_project_wrapper/config.json
```
This opens {term}`KLayout` and you should be able to see the following:
```{figure} ./mprj-gds-1.webp
:align: center
Final layout of the user_project_wrapper
```
```{tip}
You can control the visible layers in KLayout by double-clicking on the
layers you want to hide/unhide. In this figure, the layers `areaid.lowTapDensity`,
`areaid.diode`, and `areaid.standardc` were hidden to view the layout more clearly.
```
As seen in the layout, we have our aes macro placed around the middle and if we
only show the layers: `prBoundary.boundary`, `met1.drawing`, `met2.drawing`, and
`met3.drawing`. We will see long and unnecessary routes because of 2 things:
1. The AES macro is placed very far from its connections. It should be placed at
the bottom left corner.
1. The pins of the AES macro should be on the south only.
```{figure} ./mprj-gds-2.webp
:align: center
Long routes in the user_project_wrapper
```
______________________________________________________________________
#### Checking the reports
##### `OpenROAD.CheckAntennas`
There should be no antenna violations.
```
┏━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━┳━━━━━┳━━━━━┳━━━━━━━┓
┃ Partial/Required ┃ Required ┃ Partial ┃ Net ┃ Pin ┃ Layer ┃
┡━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━╇━━━━━╇━━━━━╇━━━━━━━┩
└──────────────────┴──────────┴─────────┴─────┴─────┴───────┘
```
______________________________________________________________________
##### `OpenROAD.STAPostPNR`
Looking at `xx-openroad-stapostpnr/summary.rpt` and the `Max Slew` section in
`xx-openroad-stapostpnr/max_ss_100C_1v60/checks.rpt`, there are max transition
violations. If we look at the nets with violations, we will find that those are
the long nets we saw in the GDS.
```
┏━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┓
┃ ┃ Hold Worst ┃ Reg to Reg ┃ ┃ Hold ┃ of which Reg ┃ Setup Worst ┃ Reg to Reg ┃ ┃ Setup ┃ of which Reg ┃ Max Cap ┃ Max Slew ┃
┃ Corner/Group ┃ Slack ┃ Paths ┃ Hold TNS ┃ Violations ┃ to Reg ┃ Slack ┃ Paths ┃ Setup TNS ┃ Violations ┃ to Reg ┃ Violations ┃ Violations ┃
┡━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━┩
│ Overall │ 0.0108 │ 0.0108 │ 0.0000 │ 0 │ 0 │ 1.6312 │ 7.1309 │ 0.0000 │ 0 │ 0 │ 0 │ 70 │
│ nom_tt_025C_1… │ 0.1371 │ 0.1596 │ 0.0000 │ 0 │ 0 │ 8.2216 │ 16.2820 │ 0.0000 │ 0 │ 0 │ 0 │ 45 │
│ nom_ss_100C_1… │ 0.0830 │ 0.5879 │ 0.0000 │ 0 │ 0 │ 2.2298 │ 7.6748 │ 0.0000 │ 0 │ 0 │ 0 │ 56 │
│ nom_ff_n40C_1… │ 0.0120 │ 0.0120 │ 0.0000 │ 0 │ 0 │ 10.2962 │ 19.5219 │ 0.0000 │ 0 │ 0 │ 0 │ 39 │
│ min_tt_025C_1… │ 0.1579 │ 0.1579 │ 0.0000 │ 0 │ 0 │ 8.8353 │ 16.5546 │ 0.0000 │ 0 │ 0 │ 0 │ 30 │
│ min_ss_100C_1… │ 0.1465 │ 0.5847 │ 0.0000 │ 0 │ 0 │ 2.9034 │ 8.1574 │ 0.0000 │ 0 │ 0 │ 0 │ 38 │
│ min_ff_n40C_1… │ 0.0108 │ 0.0108 │ 0.0000 │ 0 │ 0 │ 10.8591 │ 19.7016 │ 0.0000 │ 0 │ 0 │ 0 │ 28 │
│ max_tt_025C_1… │ 0.1038 │ 0.1618 │ 0.0000 │ 0 │ 0 │ 7.6237 │ 15.9806 │ 0.0000 │ 0 │ 0 │ 0 │ 65 │
│ max_ss_100C_1… │ 0.0268 │ 0.5914 │ 0.0000 │ 0 │ 0 │ 1.6312 │ 7.1309 │ 0.0000 │ 0 │ 0 │ 0 │ 70 │
│ max_ff_n40C_1… │ 0.0135 │ 0.0135 │ 0.0000 │ 0 │ 0 │ 9.7517 │ 19.3107 │ 0.0000 │ 0 │ 0 │ 0 │ 58 │
└────────────────┴────────────────┴────────────────┴──────────┴────────────────┴────────────────┴────────────────┴────────────────┴───────────┴────────────────┴────────────────┴───────────────┴────────────────┘
```
```
Max Slew
Pin Limit Slew Slack
------------------------------------------------------------------------
wbs_dat_o[2] 1.500000 5.265976 -3.765976 (VIOLATED)
wbs_dat_o[26] 1.500000 5.214964 -3.714964 (VIOLATED)
wbs_dat_o[25] 1.500000 4.767642 -3.267642 (VIOLATED)
wbs_dat_o[8] 1.500000 4.650988 -3.150988 (VIOLATED)
wbs_dat_o[23] 1.500000 4.362167 -2.862167 (VIOLATED)
wbs_dat_o[29] 1.500000 3.906245 -2.406245 (VIOLATED)
wbs_dat_o[28] 1.500000 3.703813 -2.203813 (VIOLATED)
wbs_dat_o[27] 1.500000 3.586008 -2.086008 (VIOLATED)
wbs_dat_o[31] 1.500000 3.301759 -1.801759 (VIOLATED)
wbs_dat_o[17] 1.500000 2.757454 -1.257454 (VIOLATED)
```
______________________________________________________________________
##### `Magic.DRC`
Under the directory `xx-magic-drc`, you will find a file named `reports/drc.rpt`
that summarizes the DRC violations reported by magic. The design is DRC clean so
the report will look like this:
```text
aes_wb_wrapper
----------------------------------------
[INFO] COUNT: 0
[INFO] Should be divided by 3 or 4
```
______________________________________________________________________
##### `KLayout.DRC`
Under the directory `xx-klayout-drc`, you will find a file named
`violations.json` file that summarizes the DRC violations reported by KLayout.
The design is DRC clean so the report will look like this with `"total": 0` at
the end:
```text
{
⋮
"total": 0
}
```
______________________________________________________________________
##### `Netgen.LVS`
Under the directory `xx-netgen-lvs`, you will find a file named `lvs.rpt` that
summarizes the LVS violations reported by netgen. The design is LVS clean so the
last part of the report will look like this:
```text
Cell pin lists are equivalent.
Device classes user_project_wrapper and user_project_wrapper are equivalent.
Final result: Circuits match uniquely.
```
______________________________________________________________________
#### Re-running the flow with a modified configuration
To fix the long routes issue that causes maximum transition violations, 3 things
should be done:
1. Create the pin order configuration file for `aes_wb_wrapper` in
`openlane/aes_wb_wrapper/pin_order.cfg`:
````{dropdown} pin_order.cfg
```
#S
wb_.*
wbs_.*
```
````
2. Add the `Odb.CustomIOPlacement::FP_PIN_ORDER_CFG` variable to
`openlane/aes_wb_wrapper/config.json`
````{dropdown} config.json
```json
{
"DESIGN_NAME": "aes_wb_wrapper",
"FP_PDN_MULTILAYER": false,
"CLOCK_PORT": "wb_clk_i",
"CLOCK_PERIOD": 25,
"VERILOG_FILES": [
"dir::../../../secworks_aes/src/rtl/aes.v",
"dir::../../../secworks_aes/src/rtl/aes_core.v",
"dir::../../../secworks_aes/src/rtl/aes_decipher_block.v",
"dir::../../../secworks_aes/src/rtl/aes_encipher_block.v",
"dir::../../../secworks_aes/src/rtl/aes_inv_sbox.v",
"dir::../../../secworks_aes/src/rtl/aes_key_mem.v",
"dir::../../../secworks_aes/src/rtl/aes_sbox.v",
"dir::../../verilog/rtl/aes_wb_wrapper.v"
],
"FP_CORE_UTIL": 40,
"GRT_ANTENNA_ITERS": 10,
"RUN_HEURISTIC_DIODE_INSERTION": true,
"HEURISTIC_ANTENNA_THRESHOLD": 200,
"DESIGN_REPAIR_MAX_WIRE_LENGTH": 800,
"DEFAULT_CORNER": "max_ss_100C_1v60",
"RUN_POST_GRT_DESIGN_REPAIR": true,
"PNR_SDC_FILE": "dir::pnr.sdc",
"SIGNOFF_SDC_FILE": "dir::signoff.sdc",
"FP_PIN_ORDER_CFG": "dir::pin_order.cfg"
}
```
````
3. Update the location of the macro in the
`openlane/user_project_wrapper/config.json` to `[10, 20]`
````{dropdown} config.json
```json
{
"//": "Design files",
"VERILOG_FILES": [
"dir::../../verilog/rtl/defines.v",
"dir::../../verilog/rtl/user_project_wrapper.v"
],
"PNR_SDC_FILE": "dir::signoff.sdc",
"//": "Hardening strategy variables (this is for 1-Macro-First Hardening). Visit https://docs.google.com/document/d/1pf-wbpgjeNEM-1TcvX2OJTkHjqH_C9p-LURCASS0Zo8 for more info",
"SYNTH_ELABORATE_ONLY": true,
"RUN_POST_GPL_DESIGN_REPAIR": false,
"RUN_POST_CTS_RESIZER_TIMING": false,
"DESIGN_REPAIR_BUFFER_INPUT_PORTS": false,
"FP_PDN_ENABLE_RAILS": false,
"RUN_ANTENNA_REPAIR": false,
"RUN_FILL_INSERTION": false,
"RUN_TAP_ENDCAP_INSERTION": false,
"RUN_CTS": false,
"RUN_IRDROP_REPORT": false,
"//": "Macros configurations",
"MACROS": {
"aes_wb_wrapper": {
"gds": [
"dir::../../gds/aes_wb_wrapper.gds"
],
"lef": [
"dir::../../lef/aes_wb_wrapper.lef"
],
"instances": {
"mprj": {
"location": [10, 20],
"orientation": "N"
}
},
"nl": [
"dir::../../verilog/gl/aes_wb_wrapper.v"
],
"spef": {
"min_*": [
"dir::../../spef/multicorner/aes_wb_wrapper.min.spef"
],
"nom_*": [
"dir::../../spef/multicorner/aes_wb_wrapper.nom.spef"
],
"max_*": [
"dir::../../spef/multicorner/aes_wb_wrapper.max.spef"
]
},
"lib": {
"*": "dir::../../lib/aes_wb_wrapper.lib"
}
}
},
"PDN_MACRO_CONNECTIONS": ["mprj vccd2 vssd2 VPWR VGND"],
"//": "PDN configurations",
"FP_PDN_VOFFSET": 5,
"FP_PDN_HOFFSET": 5,
"FP_PDN_VWIDTH": 3.1,
"FP_PDN_HWIDTH": 3.1,
"FP_PDN_VSPACING": 15.5,
"FP_PDN_HSPACING": 15.5,
"FP_PDN_VPITCH": 180,
"FP_PDN_HPITCH": 180,
"QUIT_ON_PDN_VIOLATIONS": false,
"//": "Magic variables",
"MAGIC_DRC_USE_GDS": true,
"MAX_TRANSITION_CONSTRAINT": 1.5,
"//": "Fixed configurations for Caravel. You should NOT edit this section",
"DESIGN_NAME": "user_project_wrapper",
"FP_SIZING": "absolute",
"DIE_AREA": [0, 0, 2920, 3520],
"FP_DEF_TEMPLATE": "dir::fixed_dont_change/user_project_wrapper.def",
"VDD_NETS": [
"vccd1",
"vccd2",
"vdda1",
"vdda2"
],
"GND_NETS": [
"vssd1",
"vssd2",
"vssa1",
"vssa2"
],
"FP_PDN_CORE_RING": 1,
"FP_PDN_CORE_RING_VWIDTH": 3.1,
"FP_PDN_CORE_RING_HWIDTH": 3.1,
"FP_PDN_CORE_RING_VOFFSET": 12.45,
"FP_PDN_CORE_RING_HOFFSET": 12.45,
"FP_PDN_CORE_RING_VSPACING": 1.7,
"FP_PDN_CORE_RING_HSPACING": 1.7,
"CLOCK_PORT": "wb_clk_i",
"SIGNOFF_SDC_FILE": "dir::signoff.sdc",
"MAGIC_DEF_LABELS": 0,
"CLOCK_PERIOD": 25,
"MAGIC_ZEROIZE_ORIGIN": 0
}
```
````
Now let's re-run the flow for the `aes_wb_wrapper`:
```console
[nix-shell:~/openlane2]$ openlane ~/caravel_aes_accelerator/openlane/aes_wb_wrapper/config.json
```
Then, after checking the `aes_wb_wrapper` reports, save the physical views
using:
```console
[nix-shell:~/openlane2]$ bash ~/caravel_aes_accelerator/openlane/copy_views.sh ~/caravel_aes_accelerator aes_wb_wrapper RUN_TAG
```
Then rerun the `user_project_wrapper`
```console
[nix-shell:~/openlane2]$ openlane ~/caravel_aes_accelerator/openlane/user_project_wrapper/config.json
```
______________________________________________________________________
#### Re-checking the layout
To open the final {term}`GDSII` layout run this command:
```console
[nix-shell:~/openlane2]$ openlane --last-run --flow openinklayout ~/caravel_aes_accelerator/openlane/user_project_wrapper/config.json
```
Now our macro is placed at the bottom left corner close to the wishbone pins.
```{figure} ./mprj-gds-3.webp
:align: center
Final layout of the user_project_wrapper
```
And if we zoom to the AES macro and view only `prBoundary.boundary`,
`met1.drawing`, `met2.drawing`, and `met3.drawing`, there are no long routes
anymore.
```{figure} ./mprj-gds-4.webp
:align: center
Shorter routes in the user_project_wrapper
```
#### Re-checking the reports
The STA report `xx-openroad-stapostpnr/summary.rpt` now has no issues:
```text
┏━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┓
┃ ┃ Hold Worst ┃ Reg to Reg ┃ ┃ Hold ┃ of which Reg ┃ Setup Worst ┃ Reg to Reg ┃ ┃ Setup ┃ of which Reg ┃ Max Cap ┃ Max Slew ┃
┃ Corner/Group ┃ Slack ┃ Paths ┃ Hold TNS ┃ Violations ┃ to Reg ┃ Slack ┃ Paths ┃ Setup TNS ┃ Violations ┃ to Reg ┃ Violations ┃ Violations ┃
┡━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━┩
│ Overall │ 0.0502 │ 0.0502 │ 0.0000 │ 0 │ 0 │ 6.0984 │ 6.6834 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ nom_tt_025C_1… │ 0.2279 │ 0.2279 │ 0.0000 │ 0 │ 0 │ 11.0441 │ 16.0780 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ nom_ss_100C_1… │ 0.3832 │ 0.7152 │ 0.0000 │ 0 │ 0 │ 6.2205 │ 7.0983 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ nom_ff_n40C_1… │ 0.0519 │ 0.0519 │ 0.0000 │ 0 │ 0 │ 11.0893 │ 19.4628 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ min_tt_025C_1… │ 0.2256 │ 0.2256 │ 0.0000 │ 0 │ 0 │ 11.0382 │ 16.3619 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ min_ss_100C_1… │ 0.4091 │ 0.7107 │ 0.0000 │ 0 │ 0 │ 6.3816 │ 7.5777 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ min_ff_n40C_1… │ 0.0502 │ 0.0502 │ 0.0000 │ 0 │ 0 │ 11.0806 │ 19.6363 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ max_tt_025C_1… │ 0.2304 │ 0.2304 │ 0.0000 │ 0 │ 0 │ 11.0653 │ 15.8331 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ max_ss_100C_1… │ 0.3418 │ 0.7198 │ 0.0000 │ 0 │ 0 │ 6.0984 │ 6.6834 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ max_ff_n40C_1… │ 0.0537 │ 0.0537 │ 0.0000 │ 0 │ 0 │ 11.1018 │ 19.2829 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
└────────────────┴────────────────┴────────────────┴──────────┴────────────────┴────────────────┴───────────────┴────────────────┴───────────┴───────────────┴────────────────┴───────────────┴────────────────┘
```
______________________________________________________________________
#### Saving the views
To save the views, run the following script with the following arguments in
order:
1. The directory of the project
1. The macro name
1. The successful run tag
```console
[nix-shell:~/openlane2]$ bash ~/caravel_aes_accelerator/openlane/copy_views.sh ~/caravel_aes_accelerator user_project_wrapper RUN_TAG
```
This will copy the physical views of the macro in the specified run to your
project folder.
Congrats! Now you have an AES accelerator as a Caravel user project.
______________________________________________________________________
## 2. Full-Wrapper Flattening strategy
In this strategy, we will harden the `user_project_wrapper` with the aes as one
large flattened macro.
### Configuration
Since we will only harden the `user_project_wrapper`. Only the
`openlane/user_project_wrapper/config.json` will be edited. The following edits
are needed for the `user_project_wrapper`
1. Add the AES Verilog files
```json
"VERILOG_FILES": [
"dir::../../../secworks_aes/src/rtl/aes.v",
"dir::../../../secworks_aes/src/rtl/aes_core.v",
"dir::../../../secworks_aes/src/rtl/aes_decipher_block.v",
"dir::../../../secworks_aes/src/rtl/aes_encipher_block.v",
"dir::../../../secworks_aes/src/rtl/aes_inv_sbox.v",
"dir::../../../secworks_aes/src/rtl/aes_key_mem.v",
"dir::../../../secworks_aes/src/rtl/aes_sbox.v",
"dir::../../verilog/rtl/aes_wb_wrapper.v",
"dir::../../verilog/rtl/defines.v",
"dir::../../verilog/rtl/user_project_wrapper.v"
],
```
1. Remove the `Macros configurations` section as there will not be any macros
1. Update the hardening strategy part to the flattened version
```json
"//": "Hardening strategy variables (this is for 2-Full-Wrapper Flattening). Visit https://docs.google.com/document/d/1pf-wbpgjeNEM-1TcvX2OJTkHjqH_C9p-LURCASS0Zo8 for more info",
"SYNTH_ELABORATE_ONLY": false,
"RUN_POST_GPL_DESIGN_REPAIR": true,
"RUN_POST_CTS_RESIZER_TIMING": true,
"DESIGN_REPAIR_BUFFER_INPUT_PORTS": true,
"FP_PDN_ENABLE_RAILS": true,
"RUN_ANTENNA_REPAIR": true,
"RUN_FILL_INSERTION": true,
"RUN_TAP_ENDCAP_INSERTION": true,
"RUN_CTS": true,
"RUN_IRDROP_REPORT": true,
"VSRC_LOC_FILES": {
"vccd1": "dir::vsrc/upw_vccd1_vsrc.loc",
"vssd1": "dir::vsrc/upw_vssd1_vsrc.loc"
},
```
Now the full configuration file will be:
````{dropdown} config.json
```json
{
"//": "Design files",
"VERILOG_FILES": [
"dir::../../../secworks_aes/src/rtl/aes.v",
"dir::../../../secworks_aes/src/rtl/aes_core.v",
"dir::../../../secworks_aes/src/rtl/aes_decipher_block.v",
"dir::../../../secworks_aes/src/rtl/aes_encipher_block.v",
"dir::../../../secworks_aes/src/rtl/aes_inv_sbox.v",
"dir::../../../secworks_aes/src/rtl/aes_key_mem.v",
"dir::../../../secworks_aes/src/rtl/aes_sbox.v",
"dir::../../verilog/rtl/aes_wb_wrapper.v",
"dir::../../verilog/rtl/defines.v",
"dir::../../verilog/rtl/user_project_wrapper.v"
],
"PNR_SDC_FILE": "dir::signoff.sdc",
"//": "Hardening strategy variables (this is for 2-Full-Wrapper Flattening). Visit https://docs.google.com/document/d/1pf-wbpgjeNEM-1TcvX2OJTkHjqH_C9p-LURCASS0Zo8 for more info",
"SYNTH_ELABORATE_ONLY": false,
"RUN_POST_GPL_DESIGN_REPAIR": true,
"RUN_POST_CTS_RESIZER_TIMING": true,
"DESIGN_REPAIR_BUFFER_INPUT_PORTS": true,
"FP_PDN_ENABLE_RAILS": true,
"RUN_ANTENNA_REPAIR": true,
"RUN_FILL_INSERTION": true,
"RUN_TAP_ENDCAP_INSERTION": true,
"RUN_CTS": true,
"RUN_IRDROP_REPORT": true,
"//": "PDN configurations",
"FP_PDN_VOFFSET": 5,
"FP_PDN_HOFFSET": 5,
"FP_PDN_VWIDTH": 3.1,
"FP_PDN_HWIDTH": 3.1,
"FP_PDN_VSPACING": 15.5,
"FP_PDN_HSPACING": 15.5,
"FP_PDN_VPITCH": 180,
"FP_PDN_HPITCH": 180,
"QUIT_ON_PDN_VIOLATIONS": false,
"//": "Magic variables",
"MAGIC_DRC_USE_GDS": true,
"MAX_TRANSITION_CONSTRAINT": 1.5,
"//": "Fixed configurations for Caravel. You should NOT edit this section",
"DESIGN_NAME": "user_project_wrapper",
"FP_SIZING": "absolute",
"DIE_AREA": [0, 0, 2920, 3520],
"FP_DEF_TEMPLATE": "dir::fixed_dont_change/user_project_wrapper.def",
"VDD_NETS": [
"vccd1",
"vccd2",
"vdda1",
"vdda2"
],
"GND_NETS": [
"vssd1",
"vssd2",
"vssa1",
"vssa2"
],
"FP_PDN_CORE_RING": 1,
"FP_PDN_CORE_RING_VWIDTH": 3.1,
"FP_PDN_CORE_RING_HWIDTH": 3.1,
"FP_PDN_CORE_RING_VOFFSET": 12.45,
"FP_PDN_CORE_RING_HOFFSET": 12.45,
"FP_PDN_CORE_RING_VSPACING": 1.7,
"FP_PDN_CORE_RING_HSPACING": 1.7,
"CLOCK_PORT": "wb_clk_i",
"SIGNOFF_SDC_FILE": "dir::signoff.sdc",
"MAGIC_DEF_LABELS": 0,
"CLOCK_PERIOD": 25,
"MAGIC_ZEROIZE_ORIGIN": 0
}
```
````
______________________________________________________________________
### Running the flow
To harden macros with OpenLane, we use the default flow, {flow}`Classic`.
```console
[nix-shell:~/openlane2]$ openlane ~/caravel_aes_accelerator/openlane/user_project_wrapper/config.json
```
The flow will finish successfully in ~2 hours and we will see:
```console
Flow complete.
```
______________________________________________________________________
### Viewing the layout
To open the final {term}`GDSII` layout run this command:
```console
[nix-shell:~/openlane2]$ openlane --last-run --flow openinklayout ~/caravel_aes_accelerator/openlane/user_project_wrapper/config.json
```
Now, we can see that there are STD cells all over the `user_project_wrapper`
without any macros. Also, we can see that the logic is clustered in the bottom
left corner close to the Wishbone bus.
```{figure} ./mprj-flattened-1.webp
:align: center
Final layout of the user_project_wrapper after flattening
```
### Checking the reports
#### `OpenROAD.CheckAntennas`
There are around 260 antenna violations with ratios up to 7.
```
┏━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━┓
┃ Partial/Required ┃ Required ┃ Partial ┃ Net ┃ Pin ┃ Layer ┃
┡━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━┩
│ 7.55 │ 400.00 │ 3018.79 │ _14743_ │ _28341_/B │ met3 │
│ 6.82 │ 400.00 │ 2727.89 │ net1493 │ _24384_/B │ met1 │
│ 4.68 │ 400.00 │ 1870.11 │ mprj.aes.core.enc_block.block_w0_reg[18\] │ _20471_/A │ met1 │
│ 3.86 │ 400.00 │ 1544.22 │ _11561_ │ _22409_/A0 │ met1 │
│ 3.80 │ 400.00 │ 1519.33 │ _11868_ │ _22752_/A0 │ met1 │
│ 3.71 │ 400.00 │ 1485.23 │ _14658_ │ fanout1328/A │ met1 │
│ 3.61 │ 400.00 │ 1443.72 │ net19 │ hold86/A │ met2 │
│ 3.45 │ 400.00 │ 1380.11 │ mprj.aes.core.enc_block.block_w1_reg[6\] │ _22727_/A1 │ met1 │
⋮
```
We can fix those the same way we did in the AES [here](#caravel-openroad-checkantennas-with-fixes).
______________________________________________________________________
#### `OpenROAD.STAPostPnR`
Looking at `xx-openroad-stapostpnr/summary.rpt`, there are multiple max Slew/Cap
violations and 1 hold violation which is not Reg to Reg.
```
┏━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┓
┃ ┃ Hold Worst ┃ Reg to Reg ┃ ┃ Hold ┃ of which Reg ┃ Setup Worst ┃ Reg to Reg ┃ ┃ Setup ┃ of which Reg ┃ Max Cap ┃ Max Slew ┃
┃ Corner/Group ┃ Slack ┃ Paths ┃ Hold TNS ┃ Violations ┃ to Reg ┃ Slack ┃ Paths ┃ Setup TNS ┃ Violations ┃ to Reg ┃ Violations ┃ Violations ┃
┡━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━┩
│ Overall │ -0.0108 │ 0.1068 │ -0.0108 │ 1 │ 0 │ 5.1907 │ 5.1907 │ 0.0000 │ 0 │ 0 │ 44 │ 275 │
│ nom_tt_025C… │ 0.1236 │ 0.3212 │ 0.0000 │ 0 │ 0 │ 11.2213 │ 15.3832 │ 0.0000 │ 0 │ 0 │ 1 │ 4 │
│ nom_ss_100C… │ 0.4500 │ 0.8885 │ 0.0000 │ 0 │ 0 │ 5.7475 │ 5.7475 │ 0.0000 │ 0 │ 0 │ 38 │ 235 │
│ nom_ff_n40C… │ 0.0365 │ 0.1079 │ 0.0000 │ 0 │ 0 │ 11.1783 │ 18.8282 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ min_tt_025C… │ 0.1726 │ 0.3196 │ 0.0000 │ 0 │ 0 │ 11.2516 │ 15.6835 │ 0.0000 │ 0 │ 0 │ 1 │ 1 │
│ min_ss_100C… │ 0.5527 │ 0.8798 │ 0.0000 │ 0 │ 0 │ 6.2822 │ 6.2822 │ 0.0000 │ 0 │ 0 │ 29 │ 168 │
│ min_ff_n40C… │ 0.0791 │ 0.1068 │ 0.0000 │ 0 │ 0 │ 11.2090 │ 19.0602 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ max_tt_025C… │ 0.0536 │ 0.3234 │ 0.0000 │ 0 │ 0 │ 11.1886 │ 15.0609 │ 0.0000 │ 0 │ 0 │ 5 │ 25 │
│ max_ss_100C… │ 0.3233 │ 0.8972 │ 0.0000 │ 0 │ 0 │ 5.1907 │ 5.1907 │ 0.0000 │ 0 │ 0 │ 44 │ 275 │
│ max_ff_n40C… │ -0.0108 │ 0.1095 │ -0.0108 │ 1 │ 0 │ 11.1440 │ 18.5834 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
└──────────────┴──────────────┴──────────────┴──────────┴──────────────┴──────────────┴───────────────┴──────────────┴───────────┴───────────────┴──────────────┴───────────────┴──────────────┘
```
The max Slew/Cap violations can be fixed the same way as in
[this section](#caravel-openroad-stapostpnr-with-fixes). For the hold violation,
it is in the `max_ff_n40C_1v95` corner. To investigate the timing path, open the
report `xx-openroad-stapostpnr/max_ff_n40C_1v95/min.rpt` and the violation will
be in the first timing path.
```{note}
There might be more hold violations or no violations at all depending on the
version of OpenLane being used as this is a violation with a very small negative
slack and the results can slightly change with OpenLane or OpenROAD updates.
```
To fix hold violations, one or more of the following solutions can be applied:
1. Enable post-global routing timing optimizations using
{var}`Classic::RUN_POST_GRT_RESIZER_TIMING`:
```json
"RUN_POST_GRT_RESIZER_TIMING": true,
```
2. Increase the hold repair margins using
{var}`OpenROAD.ResizerTimingPostCTS::PL_RESIZER_HOLD_SLACK_MARGIN` and
{var}`OpenROAD.ResizerTimingPostGRT::GRT_RESIZER_HOLD_SLACK_MARGIN`. The
default values are `0.1ns` and `0.05ns`. We can increase those as follows:
```json
"PL_RESIZER_HOLD_SLACK_MARGIN": 0.2,
"GRT_RESIZER_HOLD_SLACK_MARGIN": 0.2,
```
3. Change the default timing corner using {var}`::DEFAULT_CORNER`:
```json
"DEFAULT_CORNER": "max_tt_025C_1v80",
```
4. Most importantly, it is recommended to use a specific constraint file for
your design using {var}`OpenROAD.CheckSDCFiles::PNR_SDC_FILE` and
{var}`OpenROAD.CheckSDCFiles::SIGNOFF_SDC_FILE`
```json
"PNR_SDC_FILE": "dir::cons.sdc",
"SIGNOFF_SDC_FILE": "dir::cons.sdc",
```
______________________________________________________________________
#### `Magic.DRC`
Under the directory `xx-magic-drc`, you will find a file named `reports/drc.rpt`
that summarizes the DRC violations reported by magic. The design is DRC clean so
the report will look like this:
```text
aes_wb_wrapper
----------------------------------------
[INFO] COUNT: 0
[INFO] Should be divided by 3 or 4
```
______________________________________________________________________
#### `KLayout.DRC`
Under the directory `xx-klayout-drc`, you will find a file named
`violations.json` that summarizes the DRC violations reported by KLayout. The
design is DRC clean so the report will look like this with `"total": 0` at the
end:
```text
{
⋮
"total": 0
}
```
______________________________________________________________________
#### `Netgen.LVS`
Under the directory `xx-netgen-lvs`, you will find a file named `lvs.rpt` that
summarizes the LVS violations reported by Netgen. The design is LVS clean so the
last part of the report will look like this:
```text
Cell pin lists are equivalent.
Device classes user_project_wrapper and user_project_wrapper are equivalent.
Final result: Circuits match uniquely.
```
______________________________________________________________________
### Re-running the flow with a modified configuration
To fix the previous issues in the implementation, the following was added to the
`user_project_wrapper` config file:
```json
"//": "New variables",
"GRT_ANTENNA_ITERS": 10,
"RUN_HEURISTIC_DIODE_INSERTION": true,
"HEURISTIC_ANTENNA_THRESHOLD": 200,
"DESIGN_REPAIR_MAX_WIRE_LENGTH": 800,
"PL_WIRE_LENGTH_COEF": 0.05,
"DEFAULT_CORNER": "max_tt_025C_1v80",
"RUN_POST_GRT_DESIGN_REPAIR": true,
"RUN_POST_GRT_RESIZER_TIMING": true,
```
and the following constraints file `pnr.sdc` was created at
`~/caravel_aes_accelerator/openlane/user_project_wrapper/`. This file is
originally copied from
`~/caravel_aes_accelerator/openlane/user_project_wrapper/signoff.sdc` and edited
to fix the transition and hold violations:
````{dropdown} pnr.sdc
```tcl
# Copied from signoff.sdc then edited
### Note:
# - input clock transition and latency are set for wb_clk_i port.
# If your design is using the user_clock2, update the clock constraints to reflect that and use usr_* variables.
# - IO ports are assumed to be asynchronous. If they're synchronous to the clock, update the variable IO_SYNC to 1.
# As well, update in_ext_delay and out_ext_delay with the required I/O external delays.
#------------------------------------------#
# Pre-defined Constraints
#------------------------------------------#
set ::env(IO_SYNC) 0
# Clock network
if {[info exists ::env(CLOCK_PORT)] && $::env(CLOCK_PORT) != ""} {
set clk_input $::env(CLOCK_PORT)
create_clock [get_ports $clk_input] -name clk -period $::env(CLOCK_PERIOD)
puts "\[INFO\]: Creating clock {clk} for port $clk_input with period: $::env(CLOCK_PERIOD)"
} else {
set clk_input __VIRTUAL_CLK__
create_clock -name clk -period $::env(CLOCK_PERIOD)
puts "\[INFO\]: Creating virtual clock with period: $::env(CLOCK_PERIOD)"
}
if { ![info exists ::env(SYNTH_CLK_DRIVING_CELL)] } {
set ::env(SYNTH_CLK_DRIVING_CELL) $::env(SYNTH_DRIVING_CELL)
}
if { ![info exists ::env(SYNTH_CLK_DRIVING_CELL_PIN)] } {
set ::env(SYNTH_CLK_DRIVING_CELL_PIN) $::env(SYNTH_DRIVING_CELL_PIN)
}
# Clock non-idealities
set_propagated_clock [all_clocks]
set_clock_uncertainty 0.15 [get_clocks {clk}]
puts "\[INFO\]: Setting clock uncertainty to: 0.15"
set_clock_transition $::env(SYNTH_CLOCK_TRANSITION) [get_clocks {clk}]
puts "\[INFO\]: Setting clock transition to: $::env(SYNTH_CLOCK_TRANSITION)"
# Maximum transition time for the design nets
set_max_transition 0.75 [current_design]
puts "\[INFO\]: Setting maximum transition to: 0.75"
# Maximum fanout
set_max_fanout 16 [current_design]
puts "\[INFO\]: Setting maximum fanout to: 16"
# Timing paths delays derate
set_timing_derate -early [expr {1-0.07}]
set_timing_derate -late [expr {1+0.07}]
puts "\[INFO\]: Setting timing derate to: [expr {0.07 * 100}] %"
# Reset input delay
set_input_delay [expr $::env(CLOCK_PERIOD) * 0.5] -clock [get_clocks {clk}] [get_ports {wb_rst_i}]
# Multicycle paths
set_multicycle_path -setup 2 -through [get_ports {wbs_ack_o}]
set_multicycle_path -hold 1 -through [get_ports {wbs_ack_o}]
set_multicycle_path -setup 2 -through [get_ports {wbs_cyc_i}]
set_multicycle_path -hold 1 -through [get_ports {wbs_cyc_i}]
set_multicycle_path -setup 2 -through [get_ports {wbs_stb_i}]
set_multicycle_path -hold 1 -through [get_ports {wbs_stb_i}]
#------------------------------------------#
# Retrieved Constraints
#------------------------------------------#
# Clock source latency
set usr_clk_max_latency 4.57
set usr_clk_min_latency 4.11
set clk_max_latency 5.57
set clk_min_latency 4.65
set_clock_latency -source -max $clk_max_latency [get_clocks {clk}]
set_clock_latency -source -min $clk_min_latency [get_clocks {clk}]
puts "\[INFO\]: Setting clock latency range: $clk_min_latency : $clk_max_latency"
# Clock input Transition
set usr_clk_tran 0.13
set clk_tran 0.61
set_input_transition $clk_tran [get_ports $clk_input]
puts "\[INFO\]: Setting clock transition: $clk_tran"
# Input delays
set_input_delay -max 1.87 -clock [get_clocks {clk}] [get_ports {la_data_in[*]}]
set_input_delay -max 1.89 -clock [get_clocks {clk}] [get_ports {la_oenb[*]}]
set_input_delay -max 3.17 -clock [get_clocks {clk}] [get_ports {wbs_sel_i[*]}]
set_input_delay -max 3.74 -clock [get_clocks {clk}] [get_ports {wbs_we_i}]
set_input_delay -max 3.89 -clock [get_clocks {clk}] [get_ports {wbs_adr_i[*]}]
set_input_delay -max 4.13 -clock [get_clocks {clk}] [get_ports {wbs_stb_i}]
set_input_delay -max 4.61 -clock [get_clocks {clk}] [get_ports {wbs_dat_i[*]}]
set_input_delay -max 4.74 -clock [get_clocks {clk}] [get_ports {wbs_cyc_i}]
set_input_delay -min 0.18 -clock [get_clocks {clk}] [get_ports {la_data_in[*]}]
set_input_delay -min 0.3 -clock [get_clocks {clk}] [get_ports {la_oenb[*]}]
set_input_delay -min 0.79 -clock [get_clocks {clk}] [get_ports {wbs_adr_i[*]}]
# wbs_dat_i minimum input delay was decreased here to fix hold violations
set_input_delay -min 0.80 -clock [get_clocks {clk}] [get_ports {wbs_dat_i[*]}]
set_input_delay -min 1.19 -clock [get_clocks {clk}] [get_ports {wbs_sel_i[*]}]
set_input_delay -min 1.65 -clock [get_clocks {clk}] [get_ports {wbs_we_i}]
set_input_delay -min 1.69 -clock [get_clocks {clk}] [get_ports {wbs_cyc_i}]
set_input_delay -min 1.86 -clock [get_clocks {clk}] [get_ports {wbs_stb_i}]
if { $::env(IO_SYNC) } {
set in_ext_delay 4
puts "\[INFO\]: Setting input ports external delay to: $in_ext_delay"
set_input_delay -max [expr $in_ext_delay + 4.55] -clock [get_clocks {clk}] [get_ports {io_in[*]}]
set_input_delay -min [expr $in_ext_delay + 1.26] -clock [get_clocks {clk}] [get_ports {io_in[*]}]
}
# Input Transition
set_input_transition -max 0.14 [get_ports {wbs_we_i}]
set_input_transition -max 0.15 [get_ports {wbs_stb_i}]
set_input_transition -max 0.17 [get_ports {wbs_cyc_i}]
set_input_transition -max 0.18 [get_ports {wbs_sel_i[*]}]
set_input_transition -max 0.38 [get_ports {io_in[*]}]
set_input_transition -max 0.84 [get_ports {wbs_dat_i[*]}]
set_input_transition -max 0.86 [get_ports {la_data_in[*]}]
set_input_transition -max 0.92 [get_ports {wbs_adr_i[*]}]
set_input_transition -max 0.97 [get_ports {la_oenb[*]}]
set_input_transition -min 0.05 [get_ports {io_in[*]}]
set_input_transition -min 0.06 [get_ports {la_oenb[*]}]
set_input_transition -min 0.07 [get_ports {la_data_in[*]}]
set_input_transition -min 0.07 [get_ports {wbs_adr_i[*]}]
set_input_transition -min 0.07 [get_ports {wbs_dat_i[*]}]
set_input_transition -min 0.09 [get_ports {wbs_cyc_i}]
set_input_transition -min 0.09 [get_ports {wbs_sel_i[*]}]
set_input_transition -min 0.09 [get_ports {wbs_we_i}]
set_input_transition -min 0.15 [get_ports {wbs_stb_i}]
# Output delays
set_output_delay -max 0.7 -clock [get_clocks {clk}] [get_ports {user_irq[*]}]
set_output_delay -max 1.0 -clock [get_clocks {clk}] [get_ports {la_data_out[*]}]
set_output_delay -max 3.62 -clock [get_clocks {clk}] [get_ports {wbs_dat_o[*]}]
set_output_delay -max 8.41 -clock [get_clocks {clk}] [get_ports {wbs_ack_o}]
set_output_delay -min 0 -clock [get_clocks {clk}] [get_ports {la_data_out[*]}]
set_output_delay -min 0 -clock [get_clocks {clk}] [get_ports {user_irq[*]}]
set_output_delay -min 1.13 -clock [get_clocks {clk}] [get_ports {wbs_dat_o[*]}]
set_output_delay -min 1.37 -clock [get_clocks {clk}] [get_ports {wbs_ack_o}]
if { $::env(IO_SYNC) } {
set out_ext_delay 4
puts "\[INFO\]: Setting output ports external delay to: $out_ext_delay"
set_output_delay -max [expr $out_ext_delay + 9.12] -clock [get_clocks {clk}] [get_ports {io_out[*]}]
set_output_delay -max [expr $out_ext_delay + 9.32] -clock [get_clocks {clk}] [get_ports {io_oeb[*]}]
set_output_delay -min [expr $out_ext_delay + 2.34] -clock [get_clocks {clk}] [get_ports {io_oeb[*]}]
set_output_delay -min [expr $out_ext_delay + 3.9] -clock [get_clocks {clk}] [get_ports {io_out[*]}]
}
# Output loads
set_load 0.19 [all_outputs]
```
````
Then, the PnR SDC file path was edited in the JSON file.
```json
"PNR_SDC_FILE": "dir::pnr.sdc",
```
Now the final
`~/caravel_aes_accelerator/openlane/user_project_wrapper/config.json` file will
be:
````{dropdown} config.json
```json
{
"//": "Design files",
"VERILOG_FILES": [
"dir::../../../secworks_aes/src/rtl/aes.v",
"dir::../../../secworks_aes/src/rtl/aes_core.v",
"dir::../../../secworks_aes/src/rtl/aes_decipher_block.v",
"dir::../../../secworks_aes/src/rtl/aes_encipher_block.v",
"dir::../../../secworks_aes/src/rtl/aes_inv_sbox.v",
"dir::../../../secworks_aes/src/rtl/aes_key_mem.v",
"dir::../../../secworks_aes/src/rtl/aes_sbox.v",
"dir::../../verilog/rtl/aes_wb_wrapper.v",
"dir::../../verilog/rtl/defines.v",
"dir::../../verilog/rtl/user_project_wrapper.v"
],
"PNR_SDC_FILE": "dir::pnr.sdc",
"//": "Hardening strategy variables (this is for 2-Full-Wrapper Flattening). Visit https://docs.google.com/document/d/1pf-wbpgjeNEM-1TcvX2OJTkHjqH_C9p-LURCASS0Zo8 for more info",
"SYNTH_ELABORATE_ONLY": false,
"RUN_POST_GPL_DESIGN_REPAIR": true,
"RUN_POST_CTS_RESIZER_TIMING": true,
"DESIGN_REPAIR_BUFFER_INPUT_PORTS": true,
"FP_PDN_ENABLE_RAILS": true,
"RUN_ANTENNA_REPAIR": true,
"RUN_FILL_INSERTION": true,
"RUN_TAP_ENDCAP_INSERTION": true,
"RUN_CTS": true,
"RUN_IRDROP_REPORT": true,
"VSRC_LOC_FILES": {
"vccd1": "dir::vsrc/upw_vccd1_vsrc.loc",
"vssd1": "dir::vsrc/upw_vssd1_vsrc.loc"
},
"//": "PDN configurations",
"FP_PDN_VOFFSET": 5,
"FP_PDN_HOFFSET": 5,
"FP_PDN_VWIDTH": 3.1,
"FP_PDN_HWIDTH": 3.1,
"FP_PDN_VSPACING": 15.5,
"FP_PDN_HSPACING": 15.5,
"FP_PDN_VPITCH": 180,
"FP_PDN_HPITCH": 180,
"QUIT_ON_PDN_VIOLATIONS": false,
"//": "Magic variables",
"MAGIC_DRC_USE_GDS": true,
"MAX_TRANSITION_CONSTRAINT": 1.5,
"//": "New variables",
"GRT_ANTENNA_ITERS": 10,
"RUN_HEURISTIC_DIODE_INSERTION": true,
"HEURISTIC_ANTENNA_THRESHOLD": 200,
"DESIGN_REPAIR_MAX_WIRE_LENGTH": 800,
"PL_WIRE_LENGTH_COEF": 0.05,
"DEFAULT_CORNER": "max_tt_025C_1v80",
"RUN_POST_GRT_DESIGN_REPAIR": true,
"RUN_POST_GRT_RESIZER_TIMING": true,
"//": "Fixed configurations for Caravel. You should NOT edit this section",
"DESIGN_NAME": "user_project_wrapper",
"FP_SIZING": "absolute",
"DIE_AREA": [0, 0, 2920, 3520],
"FP_DEF_TEMPLATE": "dir::fixed_dont_change/user_project_wrapper.def",
"VDD_NETS": [
"vccd1",
"vccd2",
"vdda1",
"vdda2"
],
"GND_NETS": [
"vssd1",
"vssd2",
"vssa1",
"vssa2"
],
"FP_PDN_CORE_RING": 1,
"FP_PDN_CORE_RING_VWIDTH": 3.1,
"FP_PDN_CORE_RING_HWIDTH": 3.1,
"FP_PDN_CORE_RING_VOFFSET": 12.45,
"FP_PDN_CORE_RING_HOFFSET": 12.45,
"FP_PDN_CORE_RING_VSPACING": 1.7,
"FP_PDN_CORE_RING_HSPACING": 1.7,
"CLOCK_PORT": "wb_clk_i",
"SIGNOFF_SDC_FILE": "dir::signoff.sdc",
"MAGIC_DEF_LABELS": 0,
"CLOCK_PERIOD": 25,
"MAGIC_ZEROIZE_ORIGIN": 0
}
```
````
Now let's try re-running the flow:
```console
[nix-shell:~/openlane2]$ openlane ~/caravel_aes_accelerator/openlane/user_project_wrapper/config.json
```
The flow will finish successfully in ~2 hours and we will see:
```console
Flow complete.
```
______________________________________________________________________
### Re-checking the reports
Now, the antenna report under
`xx-openroad-checkantennas-1/reports/antenna_summary.rpt` has much less
violations:
```text
┏━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━┓
┃ Partial/Required ┃ Required ┃ Partial ┃ Net ┃ Pin ┃ Layer ┃
┡━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━┩
│ 2.03 │ 400.00 │ 810.79 │ _08755_ │ _19772_/C │ met3 │
│ 2.00 │ 400.00 │ 798.00 │ _14836_ │ _28092_/A │ met1 │
│ 1.75 │ 400.00 │ 701.33 │ _11832_ │ _22711_/A0 │ met1 │
│ 1.70 │ 400.00 │ 678.78 │ _11884_ │ _22770_/A0 │ met1 │
│ 1.62 │ 400.00 │ 647.67 │ net1481 │ _25071_/B │ met1 │
│ 1.61 │ 3130.28 │ 5050.41 │ _14758_ │ _28362_/B │ met4 │
│ 1.40 │ 3130.28 │ 4394.16 │ _14751_ │ _28352_/B │ met4 │
│ 1.39 │ 3130.28 │ 4350.98 │ _14707_ │ _28292_/B │ met4 │
⋮
```
Also, the STA report `xx-openroad-stapostpnr/summary.rpt` has no issues:
```text
┏━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┓
┃ ┃ Hold Worst ┃ Reg to Reg ┃ ┃ Hold ┃ of which Reg ┃ Setup Worst ┃ Reg to Reg ┃ ┃ Setup ┃ of which Reg ┃ Max Cap ┃ Max Slew ┃
┃ Corner/Group ┃ Slack ┃ Paths ┃ Hold TNS ┃ Violations ┃ to Reg ┃ Slack ┃ Paths ┃ Setup TNS ┃ Violations ┃ to Reg ┃ Violations ┃ Violations ┃
┡━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━┩
│ Overall │ 0.0486 │ 0.0486 │ 0.0000 │ 0 │ 0 │ 5.2837 │ 5.2837 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ nom_tt_025C… │ 0.2274 │ 0.2274 │ 0.0000 │ 0 │ 0 │ 11.0726 │ 15.1596 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ nom_ss_100C… │ 0.2414 │ 0.7146 │ 0.0000 │ 0 │ 0 │ 5.8981 │ 5.8981 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ nom_ff_n40C… │ 0.0497 │ 0.0497 │ 0.0000 │ 0 │ 0 │ 11.0978 │ 18.6822 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ min_tt_025C… │ 0.2253 │ 0.2253 │ 0.0000 │ 0 │ 0 │ 11.0640 │ 15.5219 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ min_ss_100C… │ 0.3307 │ 0.7108 │ 0.0000 │ 0 │ 0 │ 6.5295 │ 6.5295 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ min_ff_n40C… │ 0.0486 │ 0.0486 │ 0.0000 │ 0 │ 0 │ 11.0946 │ 18.9314 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ max_tt_025C… │ 0.2292 │ 0.2292 │ 0.0000 │ 0 │ 0 │ 11.0804 │ 14.7813 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ max_ss_100C… │ 0.1453 │ 0.7174 │ 0.0000 │ 0 │ 0 │ 5.2837 │ 5.2837 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ max_ff_n40C… │ 0.0509 │ 0.0509 │ 0.0000 │ 0 │ 0 │ 11.0951 │ 18.3978 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
└──────────────┴──────────────┴──────────────┴──────────┴──────────────┴──────────────┴──────────────┴──────────────┴───────────┴───────────────┴──────────────┴───────────────┴──────────────┘
```
______________________________________________________________________
### Saving the views
To save the views, run the following script with the following arguments in
order:
1. The directory of the project
1. The macro name
1. The successful run tag
```console
[nix-shell:~/openlane2]$ bash ~/caravel_aes_accelerator/openlane/copy_views.sh ~/caravel_aes_accelerator user_project_wrapper RUN_TAG
```
This will copy the physical views of the macro in the specified run to your
project folder.
Congrats! Now you have another AES accelerator as a Caravel user project.
______________________________________________________________________
## 3. Top-Level Integration strategy
In the top-level integration methodology, we will need the AES with the wishbone
wrapper as a macro, then integrate it in the User Project's Wrapper with
optimizations and cell insertion enabled on the top level.
______________________________________________________________________
### AES Wishbone Wrapper Hardening
For the AES, we can use the macro hardened in the Macro-first hardening strategy
[here](#aes-wishbone-wrapper-hardening).
______________________________________________________________________
### User Project Wrapper Hardening
#### Configuration
The following edits are needed for this strategy:
1. Change the Hardening strategy variables:
```json
"//": "Hardening strategy variables (this is for 3-Top-Level Integration). Visit https://docs.google.com/document/d/1pf-wbpgjeNEM-1TcvX2OJTkHjqH_C9p-LURCASS0Zo8 for more info",
"SYNTH_ELABORATE_ONLY": false,
"RUN_POST_GPL_DESIGN_REPAIR": true,
"RUN_POST_CTS_RESIZER_TIMING": true,
"DESIGN_REPAIR_BUFFER_INPUT_PORTS": true,
"FP_PDN_ENABLE_RAILS": true,
"RUN_ANTENNA_REPAIR": true,
"RUN_FILL_INSERTION": true,
"RUN_TAP_ENDCAP_INSERTION": true,
"RUN_CTS": true,
"RUN_IRDROP_REPORT": false,
```
2. Since we will have the AES as macro, the Macro Configurations section should
be reverted:
```json
"//": "Macros configurations",
"MACROS": {
"aes_wb_wrapper": {
"gds": [
"dir::../../gds/aes_wb_wrapper.gds"
],
"lef": [
"dir::../../lef/aes_wb_wrapper.lef"
],
"instances": {
"mprj": {
"location": [1500, 1500],
"orientation": "N"
}
},
"nl": [
"dir::../../verilog/gl/aes_wb_wrapper.v"
],
"spef": {
"min_*": [
"dir::../../spef/multicorner/aes_wb_wrapper.min.spef"
],
"nom_*": [
"dir::../../spef/multicorner/aes_wb_wrapper.nom.spef"
],
"max_*": [
"dir::../../spef/multicorner/aes_wb_wrapper.max.spef"
]
},
"lib": {
"*": "dir::../../lib/aes_wb_wrapper.lib"
}
}
},
"PDN_MACRO_CONNECTIONS": ["mprj vccd2 vssd2 VPWR VGND"],
```
3. Change the new variables section to just have the antenna and maximum
wire-length variables
```json
"//": "New variables",
"GRT_ANTENNA_ITERS": 10,
"RUN_HEURISTIC_DIODE_INSERTION": true,
"HEURISTIC_ANTENNA_THRESHOLD": 200,
"DESIGN_REPAIR_MAX_WIRE_LENGTH": 800,
"CTS_CLK_MAX_WIRE_LENGTH": 800,
```
So, the final config.json for the User Project's Wrapper will be:
````{dropdown} config.json
```json
{
"QUIT_ON_SYNTH_CHECKS": false,
"//": "Design files",
"VERILOG_FILES": [
"dir::../../verilog/rtl/defines.v",
"dir::../../verilog/rtl/user_project_wrapper.v"
],
"PNR_SDC_FILE": "dir::pnr.sdc",
"//": "Hardening strategy variables (this is for 3-Top-Level Integration). Visit https://docs.google.com/document/d/1pf-wbpgjeNEM-1TcvX2OJTkHjqH_C9p-LURCASS0Zo8 for more info",
"SYNTH_ELABORATE_ONLY": false,
"RUN_POST_GPL_DESIGN_REPAIR": true,
"RUN_POST_CTS_RESIZER_TIMING": true,
"DESIGN_REPAIR_BUFFER_INPUT_PORTS": true,
"FP_PDN_ENABLE_RAILS": true,
"RUN_ANTENNA_REPAIR": true,
"RUN_FILL_INSERTION": true,
"RUN_TAP_ENDCAP_INSERTION": true,
"RUN_CTS": true,
"RUN_IRDROP_REPORT": false,
"//": "Macros configurations",
"MACROS": {
"aes_wb_wrapper": {
"gds": [
"dir::../../gds/aes_wb_wrapper.gds"
],
"lef": [
"dir::../../lef/aes_wb_wrapper.lef"
],
"instances": {
"mprj": {
"location": [1500, 1500],
"orientation": "N"
}
},
"nl": [
"dir::../../verilog/gl/aes_wb_wrapper.v"
],
"spef": {
"min_*": [
"dir::../../spef/multicorner/aes_wb_wrapper.min.spef"
],
"nom_*": [
"dir::../../spef/multicorner/aes_wb_wrapper.nom.spef"
],
"max_*": [
"dir::../../spef/multicorner/aes_wb_wrapper.max.spef"
]
},
"lib": {
"*": "dir::../../lib/aes_wb_wrapper.lib"
}
}
},
"PDN_MACRO_CONNECTIONS": ["mprj vccd2 vssd2 VPWR VGND"],
"//": "PDN configurations",
"FP_PDN_VOFFSET": 5,
"FP_PDN_HOFFSET": 5,
"FP_PDN_VWIDTH": 3.1,
"FP_PDN_HWIDTH": 3.1,
"FP_PDN_VSPACING": 15.5,
"FP_PDN_HSPACING": 15.5,
"FP_PDN_VPITCH": 180,
"FP_PDN_HPITCH": 180,
"QUIT_ON_PDN_VIOLATIONS": false,
"//": "Magic variables",
"MAGIC_DRC_USE_GDS": true,
"MAX_TRANSITION_CONSTRAINT": 1.5,
"//": "New variables",
"GRT_ANTENNA_ITERS": 10,
"RUN_HEURISTIC_DIODE_INSERTION": true,
"HEURISTIC_ANTENNA_THRESHOLD": 200,
"DESIGN_REPAIR_MAX_WIRE_LENGTH": 800,
"CTS_CLK_MAX_WIRE_LENGTH": 800,
"//": "Fixed configurations for caravel. You should NOT edit this section",
"DESIGN_NAME": "user_project_wrapper",
"FP_SIZING": "absolute",
"DIE_AREA": [0, 0, 2920, 3520],
"FP_DEF_TEMPLATE": "dir::fixed_dont_change/user_project_wrapper.def",
"VDD_NETS": [
"vccd1",
"vccd2",
"vdda1",
"vdda2"
],
"GND_NETS": [
"vssd1",
"vssd2",
"vssa1",
"vssa2"
],
"FP_PDN_CORE_RING": 1,
"FP_PDN_CORE_RING_VWIDTH": 3.1,
"FP_PDN_CORE_RING_HWIDTH": 3.1,
"FP_PDN_CORE_RING_VOFFSET": 12.45,
"FP_PDN_CORE_RING_HOFFSET": 12.45,
"FP_PDN_CORE_RING_VSPACING": 1.7,
"FP_PDN_CORE_RING_HSPACING": 1.7,
"CLOCK_PORT": "wb_clk_i",
"SIGNOFF_SDC_FILE": "dir::signoff.sdc",
"MAGIC_DEF_LABELS": 0,
"CLOCK_PERIOD": 25,
"MAGIC_ZEROIZE_ORIGIN": 0
}
```
````
______________________________________________________________________
#### Running the flow
To harden macros with OpenLane, we use the default flow, {flow}`Classic`.
```console
[nix-shell:~/openlane2]$ openlane ~/caravel_aes_accelerator/openlane/user_project_wrapper/config.json
```
The flow will finish successfully in ~1.5 hours and we will see:
```console
Flow complete.
```
______________________________________________________________________
#### Viewing the layout
To open the final {term}`GDSII` layout run this command:
```console
[nix-shell:~/openlane2]$ openlane --last-run --flow openinklayout ~/caravel_aes_accelerator/openlane/user_project_wrapper/config.json
```
Now, we can see that there are STD cells all over the `user_project_wrapper` and
there is our macro in the middle.
```{figure} ./mprj-top-1.webp
:align: center
Final layout of the user_project_wrapper with Top-level integration
```
### Checking the reports
#### `OpenROAD.CheckAntennas`
There are no antenna violations at all since we already have the antenna
variables in our configuration.
```
┏━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━┳━━━━━┳━━━━━┳━━━━━━━┓
┃ Partial/Required ┃ Required ┃ Partial ┃ Net ┃ Pin ┃ Layer ┃
┡━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━╇━━━━━╇━━━━━╇━━━━━━━┩
└──────────────────┴──────────┴─────────┴─────┴─────┴───────┘
```
______________________________________________________________________
#### `OpenROAD.STAPostPnR`
Looking at `xx-openroad-stapostpnr/summary.rpt`, there are no issues.
```
┏━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━┓
┃ ┃ Hold Worst ┃ Reg to Reg ┃ ┃ Hold ┃ of which Reg ┃ Setup Worst ┃ Reg to Reg ┃ ┃ Setup ┃ of which Reg ┃ Max Cap ┃ Max Slew ┃
┃ Corner/Group ┃ Slack ┃ Paths ┃ Hold TNS ┃ Violations ┃ to Reg ┃ Slack ┃ Paths ┃ Setup TNS ┃ Violations ┃ to Reg ┃ Violations ┃ Violations ┃
┡━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━┩
│ Overall │ 0.0394 │ 0.0394 │ 0.0000 │ 0 │ 0 │ 2.9640 │ 7.0837 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ nom_tt_025C_… │ 0.2089 │ 0.2089 │ 0.0000 │ 0 │ 0 │ 9.2328 │ 16.3319 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ nom_ss_100C_… │ 0.6504 │ 0.6504 │ 0.0000 │ 0 │ 0 │ 3.2635 │ 7.4518 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ nom_ff_n40C_… │ 0.0444 │ 0.0444 │ 0.0000 │ 0 │ 0 │ 10.9069 │ 19.5798 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ min_tt_025C_… │ 0.2026 │ 0.2026 │ 0.0000 │ 0 │ 0 │ 9.4448 │ 16.5702 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ min_ss_100C_… │ 0.6390 │ 0.6390 │ 0.0000 │ 0 │ 0 │ 3.5688 │ 7.8739 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ min_ff_n40C_… │ 0.0394 │ 0.0394 │ 0.0000 │ 0 │ 0 │ 10.9061 │ 19.7497 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ max_tt_025C_… │ 0.2205 │ 0.2205 │ 0.0000 │ 0 │ 0 │ 9.0069 │ 16.1275 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ max_ss_100C_… │ 0.6725 │ 0.6725 │ 0.0000 │ 0 │ 0 │ 2.9640 │ 7.0837 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
│ max_ff_n40C_… │ 0.0515 │ 0.0515 │ 0.0000 │ 0 │ 0 │ 10.9095 │ 19.4285 │ 0.0000 │ 0 │ 0 │ 0 │ 0 │
└───────────────┴───────────────┴───────────────┴──────────┴───────────────┴──────────────┴───────────────┴──────────────┴───────────┴───────────────┴──────────────┴───────────────┴──────────────┘
```
```{admonition} Note
:class: seealso
Despite the fact that the macro is placed very far from the top-level pins, there are no maximum slew violations because optimizations are enabled at the top-level and the long routes are being buffered.
```
______________________________________________________________________
#### `Magic.DRC`
Under the directory `xx-magic-drc`, you will find a file named `reports/drc.rpt`
that summarizes the DRC violations reported by magic. The design is DRC clean so
the report will look like this:
```text
aes_wb_wrapper
----------------------------------------
[INFO] COUNT: 0
[INFO] Should be divided by 3 or 4
```
______________________________________________________________________
#### `KLayout.DRC`
Under the directory `xx-magic-drc`, you will find a file named `violations.json`
that summarizes the DRC violations reported by KLayout. The design is DRC clean
so the report will look like this with `"total": 0` at the end:
```text
{
⋮
"total": 0
}
```
______________________________________________________________________
#### `Netgen.LVS`
Under the directory `xx-netgen-lvs`, you will find a file named `lvs.rpt` that
summarizes the LVS violations reported by netgen. The design is LVS clean so the
last part of the report will look like this:
```text
Cell pin lists are equivalent.
Device classes user_project_wrapper and user_project_wrapper are equivalent.
Final result: Circuits match uniquely.
```
______________________________________________________________________
#### Saving the views
To save the views, run the following script with the following arguments in
order:
1. The directory of the project
1. The macro name
1. The successful run tag
```console
[nix-shell:~/openlane2]$ bash ~/caravel_aes_accelerator/openlane/copy_views.sh ~/caravel_aes_accelerator user_project_wrapper RUN_TAG
```
This will copy the physical views of the macro in the specified run to your
project folder.
Congrats! Now you have a third different AES accelerator as a Caravel user
project.