KEYMGR DV document

Goals

DV
- Verify all KEYMGR IP features by running dynamic simulations with a SV/UVM based testbench
- Develop and run all tests based on the testplan below towards closing code and functional coverage on the IP and all of its sub-modules
FPV
- Verify TileLink device protocol compliance with an SVA based testbench

Design features

For detailed information on KEYMGR design features, please see the KEYMGR HWIP technical specification.

Testbench architecture

KEYMGR testbench has been constructed based on the CIP testbench architecture.

Top level testbench is located at hw/ip/keymgr/dv/tb/tb.sv. It instantiates the KEYMGR DUT module hw/ip/keymgr/rtl/keymgr.sv. In addition, it instantiates the following interfaces, connects them to the DUT and sets their handle into uvm_config_db:

Clock and reset interface
TileLink host interface
KEYMGR IOs (keymgr_if)
Interrupts (pins_if)
Alerts (alert_esc_if)

Common DV utility components

The following utilities provide generic helper tasks and functions to perform activities that are common across the project:

Compile-time configurations

[list compile time configurations, if any and what are they used for]

Global types & methods

All common types and methods defined at the package level can be found in keymgr_env_pkg. Some of them in use are:

[list a few parameters, types & methods; no need to mention all]

TL_agent

KEYMGR testbench instantiates (already handled in CIP base env) tl_agent which provides the ability to drive and independently monitor random traffic via TL host interface into KEYMGR device.

EDN Agent

The KEYMGR testbench instantiates a push_pull_agent in Pull mode as the agent modelling the EDN interface (this is already handled in the CIP base classes). This agent will return random data as entropy when the KEYMGR sends a request.

KMAC_APP Agent

The KEYMGR testbench instantiates a kmac_app_agent to request a KMAC hash operation on the secret data.

UVM RAL Model

The KEYMGR RAL model is created with the ralgen FuseSoC generator script automatically when the simulation is at the build stage.

It can be created manually by invoking regtool:

Reference models

[Describe reference models in use if applicable, example: SHA256/HMAC]

Stimulus strategy

Test sequences

All test sequences reside in hw/ip/keymgr/dv/env/seq_lib. The keymgr_base_vseq virtual sequence is extended from cip_base_vseq and serves as a starting point. All test sequences are extended from keymgr_base_vseq. It provides commonly used handles, variables, functions and tasks that the test sequences can simple use / call. Some of the most commonly used tasks / functions are as follows:

keymgr_operations: This task issues operations as set in the inputs, such as advance operation, generating sw/hw output.
wait_op_done: This task polls the op_status until it returns success / fail status, as well as checking if the status is expected.
keymgr_rd_clr: This reads sw_share_output to allow scoreboard to check the values.

Functional coverage

To ensure high quality constrained random stimulus, it is necessary to develop a functional coverage model. The covergroups defined in testplan have been developed to prove that the test intent has been adequately met.

Self-checking strategy

Scoreboard

The keymgr_scoreboard is primarily used for end to end checking. It creates the following analysis ports to retrieve the data monitored by corresponding interface agents:

tl_a_chan_fifo: An analysis FIFO to hold transactions from TL address channel.
tl_d_chan_fifo: An analysis FIFO to hold transactions from TL data channel.
req_fifo: An analysis FIFO to hold request data sent to KMAC.
rsp_fifo: An analysis FIFO to hold response digests received from KMAC.
edn_fifo: An analysis FIFO to hold transactions coming from the EDN interface.

Assertions

TLUL assertions: The tb/keymgr_bind.sv binds the tlul_assert assertions to the IP to ensure TileLink interface protocol compliance.
Unknown checks on DUT outputs: The RTL has assertions to ensure all outputs are initialized to known values after coming out of reset.
Check(Kmac|Aes|Otbn)Key: Check keys on the 3 sideload interfaces.
CheckEdn1stReq / CheckEdn2ndReq: Check KEYMGR sends 2 EDN request periodically based on the CSR reseed_interval.

Building and running tests

We are using our in-house developed regression tool for building and running our tests and regressions. Please take a look at the link for detailed information on the usage, capabilities, features and known issues. Here’s how to run a smoke test:

$ $REPO_TOP/util/dvsim/dvsim.py $REPO_TOP/hw/ip/keymgr/dv/keymgr_sim_cfg.hjson -i keymgr_smoke