a systematic approach to soft ip quality...unsynchronized cdc paths 236 240 0 0 102 106 cdc goal...

© 2012 Atrenta Inc.

A Systematic Approach to Soft IP Quality

Anuj Kumar October 2012

2 © 2012 Atrenta Inc.

IP Use Is On The Rise

Source: IBS Inc., August 2012


And So Is Cost

Much of this IP is soft, or synthesizable

Source: IBS Inc., August 2012


Taming Cost Means Reducing Risk

Can’t reach test goals

Routing congestion

Can’t close timing

Too much power

Design bugs

Incomplete deliverables


Atrenta’s Approach – IP Kit

Atrenta IP Kit

IP

SpyGlass Clean IP

IP reports

Atrenta DataSheet

Atrenta DashBoard

IP design intent

….

RTL

wai

vers

Standard methodology Setup & run automation

Quickstart Guide

Training module Li

nt +

+

CD

C

DFT

Pow

er

Con

str

SDC

SG

DC

UPF

/CPF

FS

DB

,…

Scripts, setup

Deliverables

Phys

ical


Key Component – SpyGlass

Complete platform to optimize RTL - Lint, CDC, DFT, Constraints, Power and Routing Congestion

GuideWare provides best practices for high impact, low noise analysis

RTL problems easily identified

Richest set of engines that identify real implementation issues


Design readSetup

Results database

OptimizeDebug

GuideWare Methodology

ConstraintsCDC

Lint

PowerDFT

Automatically generates HTML DashBoard and DataSheet reports

to track design quality & design specs

And Data Management Addition

Configuration Management

System (CVS, Clearcase, RCS, …)

Check-in updates

Automated nightly runs

Met

hodo

logy

SpyGlass RTL Platform


And Some Help From Our Friends

TSMC and Atrenta announced the Soft IP Qualification Flow in May 2011 Focus – qualify the robustness and completeness of synthesizable IP that is part of the TSMC 9000 library for TSMC’s customers


Overview of TSMC Program

IP1

IP 2

IP 3

IP n

IP ecosystem partners

Handoff

Atrenta DashBoard

Atrenta DataSheet

Atrenta summary reports

● ● ●

Atrenta IP Kit

Chip project 1

Chip project 2

Chip project 3

Chip project n

End customers

Atrenta IP Kit

Inspection/ Acceptance

● ●

●

TSMC Online


WHAT DOES THE IP KIT CHECK AND WHAT HAVE WE FOUND?


Sample Tests – IP Handoff Kit V 1.0 What will the average power dissipation be?

Are my power domains correctly defined?

Are clock and reset constraints set properly?

Are clock definitions consistent, correct and complete?

Are clock domain crossing synchronizers bug-free?

Are timing constraints consistent across block boundaries?

Are false path and multi-cycle paths correctly identified?

Is the design ready for simulation and synthesis?

What will the stuck-at and at-speed test coverage be?

Can all sequential elements be scanned?

Lint

Test

Power

Clocks &

Timing


What Did We Find?

Many items that would impact integration/debug time and chip function were found & fixed

Some examples:

Missing synchronizers on CDC paths causing possible chip function issues

Data loss on a fast-slow CDC paths

Uncontrolled data path impacting transition fault coverage

Index out of range which causes synthesizability issues

Unconstrained I/O ports leading to poor SDC coverage


IP Kit 2.0 – Need & Motivation

Improve soft IP handoff quality checks Align TSMC IP Kit methodology with Atrenta’s latest GuideWare 2.0

methodology providing high coverage and low noise IP handoff checks Introduce additional design checks

• Advanced formal lint (e.g., X-assignment, dead code detection, etc.) • Physical implementation data (e.g., area, timing & congestion)

Improve the IP Kit setup & flow execution Automatic generation of setup files Flexibility in goal running (single/multiple/goal group) Incremental analysis

Easier integration of SpyGlass in customer’s existing design flow

Improved IP packaging


IP Kit 2.0 Execution Flow

IP Packaging >% aipk_pack –top foo –save_all

Advanced Design Checks >% aipk_run –top foo –goals adv_check

Basic Design Checks >% aipk_run –top foo –goals basic_check

Design Setup Checks >% aipk_read –top foo

Design Read >% aipk_read -top foo –srcfile foo.f –libfile lib.f –sdcfile foo.sdc -activity_file foo.vcd

Auto-generation of SpyGlass setup files (.prj, .sgdc, .swl, .dat etc) Generation of Design Read DashBoard report Ensures that RTL is read successfully in SpyGlass

Identifies unconstrained clock/resets in the design

Ensures that design setup is complete & correct

Runs basic IP Handoff checks (Lint, CDC-structural, DFT, SDC, Power)

Generates quality report for basic design checks/goals

Runs Advanced IP Handoff checks (CDC-functional, Lint-functional and Physical)

Generates overall quality report combining results for basic & advanced checks

Packages an IP with design intent, setup & analysis reports


Design Read DashBoard Report


TSMC IP Kit 2.0 – Mandatory Goals

Domain Goal Name Purpose Handoff Check Type

Lint

lint_rtl Checks the design for simulation/synthesis readiness, connectivity & structural issues Basic

clock_reset_integrity Checks the integrity of clock and reset propagation and architecture Basic

Advanced Lint

adv_lint_struct Checks for X-assignment, FSM transition, deadlock issues based design topology analysis Advanced

adv_lint_verify Checks the functional issues in FSM transition, static code, bus overflow & X-assignments based on formal verification analysis Advanced

CDC

cdc_setup_check Checks the completeness of clock & reset constraints Basic

cdc_structural_check Exhaustive verification all synchronization checking for CDCs and asynchronous reset signals based on design topology checking Basic

cdc_functional_check Exhaustive verification of functional aspects of the CDC path and synchronizers using formal analysis techniques Advanced

DFT

dft_best_practices Checks the design for best practices to increase ATPG effectiveness and efficiency Basic

dft_scan_ready Checks if all sequential elements are scannable or not. Also generates the coverage audit report Basic

dft_test_points Helps in improving the test coverage by identifying the uncontrollable and unobservable nodes in the design Basic

dft_dsm_clocks Helps in defining the clocks used for at-speed testing and any associated PLL ,etc. Basic

dft_dsm_best_practices Addresses special needs of cases such as d-pin controllability, test clock domains and path issues. Also generates the transition coverage audit report Basic

Goal Enhanced Legend: New Goal Added


Domain Goal Name Purpose Handoff Check Type

Power power_est_average Estimates the average power of the design Basic

Power Verification

power_verif_instr_rtl Verifies the desired power intent in the RTL design as per given power constraints Basic

Constraints

sdc_setup_check Performs sanity checking on SDC file Basic

sdc_audit Computes constraints coverage for design objects like as IOs, flops, etc. Basic

sdc_check Ensures that clock & IO delay definitions defined in the SDC file are consistent, correct & complete Basic

sdc_exception_struct Ensures that given timing exceptions constraints exist in the design Basic

sdc_redundancy_check Help in removing the redundancy in constraints definition Basic

TXV fp_verification Helps in the verification of false path constraints Advanced

mcp_verification Helps in the verification of multi-cycle path constraints Advanced

Physical physical_analysis_signoff Performs physical analysis using vendor library, used for signoff on area, congestion and timing (based on pre-floorplan checks) Advanced

TSMC IP Kit 2.0 – Mandatory Goals



TSMC IP Kit 2.0 – Optional Goals Domain Goal Name Purpose Handoff

Check Type

Lint design_audit Provides basic design profile data and generates the IO data for the population of DataSheet reports. This goal is automatically run during IP Kit Design Read stage, hence kept as an optional goal and user does not need to run it explicitly

Basic

Power

power_audit

Reports all given key design data, inputs and parameters, which will be used for power estimation analysis. This report indicates the completeness of design setup for power estimation analysis. . This goal is automatically run during the IP Kit Design Read stage, hence kept as an optional goal and user does not need to run it explicitly

Basic

power_est_cycle Calculate power for each cycle of the simulation profile file. As this goal computes power for each cycle of simulation waveform, it may take huge run time if given simulation file(VCD/FSDB) is quite big, hence kept as an optional goal

Basic

Power Verification power_verif_audit

Does the audit/completeness check on given UPF/CPF file. This goal is automatically run during the IP Kit Design Read stage if the user has provided any power intent file like UPF or CPF. Hence kept as an optional goal

Basic

Constraints

sdc_hierarchical_check Ensures that constraints are consistent across the block boundaries. This goal would become applicable for running if SDC files exist both for the top design and underlying sub-blocks

Basic

sdc_equiv Ensures that different versions of the SDC files are equivalent for the same design. This goal can only be run if there exist two sets of the SDC file(s) for an IP

Advanced

Physical physical_library_preparation Prepare the technology library in the requisite OA format, which is a must for running other SpyGlass Physical goal runs. . This goal is automatically run during the IP Kit Design Read stage, hence kept as an optional goal and user does not need to run it again explicitly

Advanced



IP Kit 2.0 vs. 1.0 Benchmark Data

Design Quality Objective

IP#1 IP#2 IP#3 Comments

IPK 2.0 IPK 1.0 IPK 2.0 IPK 1.0 IPK 2.0 IPK 1.0

Unsynchronized CDC paths 236 240 0 0 102 106 CDC goal optimized to avoid false unsynchronized violations

Stuck-at fault coverage 82.7 82.7 100 100 99.8 99.8

Stuck-at test coverage 83.7 83.7 100 100 99.8 99.8

% of scannable flops 89 89 100 100 99 99

Transition fault coverage 51.3 51.3 95.5 95.5 73.3 73.3

Transition test coverage 77.7 77.7 95.8 95.8 95.2 95.2

% of IO ports constrained in SDC file 93.9 93.9 100 100 100 100

% of registers constraints in SDC file 100 100 100 100 100 100

Switching power(in mW) 0.32 0.32 5.98 5.98 2.24 2.24

Internal power(in mW) 1.05 1.05 44.2 44.2 11.5 11.5

Leakage power(in mW) 0.005 0.005 0.13 0.13 0.02 0.02

Total power(in mW) 1.37 1.37 50.3 50.3 13.8 13.8

Improved QA Legend: Additional QA


Benchmark Data (cont’d)

Design Quality Objective

IP#1 IP#2 IP#3 Comments

IPK 2.0 IPK 1.0 IPK 2.0 IPK 1.0 IPK 2.0 IPK 1.0

Gate count (NAND equivalent) 9.2K 9.9K 1.72M 2.2M 48K 70.5K Gate count calculation is more accurate in IP Kit K2.0 – based on SpyGlass Physical analysis

Flop count 741 745 50422 53581 4490 4546

Latch count 5 5 1175 1179 0 0

No. of timing paths failing 0 NA 0 NA 0 NA

No. of congested module instances 0 NA 10 NA 0 NA

Floating inputs 0 0 0 0 0 0

Multiply driven nets 0 0 0 0 0 0

Cyclomatic complexity 63 NA 1559 NA 257 NA

Run time for common (existing) goals 824 1109 8197 9520 9550 9616 Run time reduced an average by 10-15% for

common goals

Total number of errors 619 386 1147 125 122 115 New & improved error rules catching additional critical design issues

Total number of warnings 796 1369 1911 7614 214 918 Goal enhancement/optimization helped to control the violation reported for less severe rules (warnings)

Improved QA Legend: Additional QA


IP Specification Report SpyGlass DataSheet report capturing key design specifications and profile

statistics, once all goals run are finished

Design Read

Design Setup Check

Design Analysis

IP Packaging


Design Quality & Status Summary Report

SpyGlass DashBoard report capturing the high-level design quality metrics and goal run summary report, once all goals run are finished


Conclusion

Soft IP qualification can be automated Results in higher quality deliverables, reduced cost and better schedules All soft IP can be improved System is currently deployed at several large customers and through TSMC’s soft IP qualification program TSMC program participation growing and on-track

a systematic approach to soft ip quality...unsynchronized cdc paths 236 240 0 0 102 106 cdc goal...

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