The document describes Cisco's Base Environment methodology for digital verification. It aims to standardize the verification process, promote reuse, and improve predictability. The methodology defines a common testbench topology and infrastructure that is vertically scalable from unit to system level and horizontally scalable across projects. It provides templates, scripts, verification IP and documentation to help teams set up verification environments quickly and leverage existing best practices. The standardized approach facilitates extensive code and test reuse and delivers benefits such as faster ramp-up times, improved planning, and higher return on verification IP development.

1. Cisco Base Environment
Overview
Joseph Zhang
September 2007
Base Env © 2006, Cisco Systems, Inc. All rights reserved. 1

2. Agenda
• Motivation
• Description
• Benefits
• Q and A
Base Env © 2006, Cisco Systems, Inc. All rights reserved. 2

3. Standardize on Reuse Methodology
• Design reuse not enough – Verification
increasingly becoming schedule bottleneck.
• Leverage best practices from previous
projects.
Motivation
Focus on methodology, not language or
implementation.
• Ultimate goals:
unit-level to chip-level reuse.
leverage automation to reduce labor intensive tasks.
educate and empower DV staff.
improve scheduling predictability.
Base Env © 2006, Cisco Systems, Inc. All rights reserved. 3

4. Agenda
• Motivation
• Description
• Benefits
• Q and A
Base Env © 2006, Cisco Systems, Inc. All rights reserved. 4

5. Standard ASIC DV Methodology
• Defines Common Topology and Directory
Structure
Description
• Leverage Existing Best Practices
Shaggy, Scooby, Marmot, Cobalt, GoldenEye, XChip, etc…
• Vertically Scalable from Unit to System
• Horizontally Scalable Across Projects
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6. Investment
• Development Spanned 10 Calendar Months
Team consists of DV leads from RTP and BXB
• Implemented Methodology in Specman
Description
Toolkit
Scripts
Templates
12 Verification IP
Documentation and
Training Material and Sessions
• Created Reference Project (Newby)
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7. Implementation Overview
MY_CHIP csco_tb_u
TB VSD
Seq
Seq
Seq
clkgen
Description
auto-created by
eVC topology script
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8. Additional Tool Enhancements
• csco_verbosity
Displays all of the available message loggers
Enables user to create a file that can change logger
settings (or apply any other Specman command) at
Description
specific simulation times
• csco_ovl_specman
Package consisting of OVL, Verilog, and e code that
turns each OVL assertion event into a Specman event
for use in either coverage or checking
Ties assertion based verification (ABV) with coverage
driven verification (CDV)
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9. Agenda
• Motivation
• Description
• Benefits
• Q and A
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10. Extensive Reuse
• Reuse of Techniques
Coding techniques that address complex testbench functions are in the
testbench from the beginning of the project
• Reuse of Specification
Tight integration with Blueprint enables source for RTL creation to also be used
for testbench creation
Benefits
• Reuse of Code
Vertical Scaling - all unit benches may be reused at higher levels, even up to
system simulations
Horizontal Scaling - verification components may be reused between projects
• Reuse of Tests
Standardization of testbench infrastructure allows some tests to be automatically
created and many others to be reused or leveraged at higher levels
• Reuse of Training
Commonality of look and feel of testbench infrastructure means no need to re-
learn testbench interfaces
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11. Improved Predictability
• Planning
Common infrastructure allows more detailed and accurate
planning
• Execution
Horizontal scaling and improved training results in quicker
Benefits
ramp up time for verification resources
Vertical scaling enables focused unit testing resulting in
greater parallel use of resources
Large reusable code base reduces code development
• Success
Early testing ensures DUT is sanity checked early
Methodology and underlying packages ensure that DUT has
been adequately exercised and checked
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12. Higher Return on VIP Development
• Methodology is required to support VIP reuse
Common language helps but is not nearly enough
Standardization required
Configuration interface
Inter-process communication
Benefits
Stimulus generation
Scoreboarding schemes
• Cisco Base Environment VIP
Standard interface and usage model allows quick integration
into TB
More mileage and maturity from our VIP will reduced
verification cost
People will actually want to use the VIP!
Base Env © 2006, Cisco Systems, Inc. All rights reserved. 12

13. Solves Common DV Problems
• How can I quickly start a DV environment?
The templates and scripts in Cisco Base Environment
make it easy to instantiate the infrastructures of a DV
environment in < 1 day
Benefits
Invoke make_proj_vob.pl to create
directory structure and chip-level TB
skeleton
Invoke mkevc.pl to create skeleton VIP
packages to drive/monitor interface
Invoke make_unit_pkg.pl to create skeleton
environments for each unit-level TB
Base Env © 2006, Cisco Systems, Inc. All rights reserved. 13

14. Solves Common DV Problems
• How can I make sure my unit-level TB and
testcases can be reused at the chip-level and
higher?
csco_addrmap package ensures that CPU transactions
are transparent from unit-level to chip-level
Benefits
csco_event package ensures that interrupt handling is
transparent from unit-level to chip-level
csco_trans enables sum-of-parts scoreboarding where
unit-level scoreboards are chained to form end-to-end
scoreboard
csco_testflow ensures that all TB components execute
in sync. with reach other, across all TB levels
csco_clkgen provides transparent clock generation and
sampling across all TB levels
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15. Solves Common DV Problems
• How do I know I’ve accurately and
sufficiently modeled the DUT registers?
Tight Blueprint integration means same RDL is
used to generate both RTL and DV code
Benefits
Predefined test sequences in csco_addrmap
and csco_event are used to perform automatic
structural testing on registers and interrupts
Blueprint code generator also creates DV
configuration modules from control registers
in RDL
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16. Solves Common DV Problems
• How can I make sure my TB can support
dynamic resets?
Benefits
csco_config supports dynamic full or partial
regeneration of TB configuration tree
csco_testflow supports reset of all or any
portion of the TB with automatic re-launching
of initialization and test stimulus
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17. Solves Common DV Problems
• How do I start debugging once something goes
wrong?
csco_trans links and archives all transactions in the
TB, reducing the need to generate huge waveforms
Benefits
csco_testflow issues timeout errors when a TB
component stalls the simulation
csco_trans issues timeout errors when a transaction
spends too much time in the TB
csco_verbosity allows user to interactively inject TB
commands, reducing dependency on often slow and
cumbersome GUI
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18. Agenda
• Motivation
• Description
• Benefits
• Q and A
Base Env © 2006, Cisco Systems, Inc. All rights reserved. 18

19. Base Env © 2006, Cisco Systems, Inc. All rights reserved. 19