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Conformal-LP : Understanding liberty files.

nitint08
Hi

Conformal can read liberty files but the relevant lowpower special cells
are not recognised until those are specially specified with define_* cpf command.

Since Conformal has all the information of library cells (i.e. AON-cells, retention-
cells, power-switches, iso-cells,level-shifters etc) thus it would be more benefical
if this information can also be provided to the user so that he can correct his
list of cells via relevant define_* commands.

Regards
NitinT

  • CLP can read in LP libs (liberty).

    read library -liberty -lp

    Will this work for you or are you asking about something else?

    -ts

     

     

  • Thanks for prompt response (for other queries also).

    Yes, CLP is reading liberty files and also able to report all the cells specified in it via "report library data"

    But it is not able to identify LowPower cells having relevant liberty attributes applied to them if those

    cell are not specified in CPF via "define_*" commands.

    If a normal cell is specified as Isolation-cell via "define_isolation_cell" command than it is accepted as isolation-cell.

    Thus following are observed, please confirm?

    1. LP cells are only identified via "define_*" CPF commands.

    2. Liberty attributes for Lowpower are not considered by Conformal.

    3. read library -liberty *.lib command only identify the cells and maps to cells under define_* commands.

    4. Any LP cell if not specified with define_* command but found in library and in design will not be considered as

        relevant cell and CLP will flag violation of missing cell and not incorrect cell.

    5. Is there any rule in CLP which can identify such special cells which are not defined via define_* command.

    Thanks in advance.

  • Can you confirm you are using

    read library -liberty -lp

    ?

    The -lp switch is what pulls in the liberty low power data.

    You will also need to use a more recent version for best results. I think the -lp switch has worked well since 11.1 (or earlier) but the current version is 12.1.

     

    -ts

  • Yes, forsure i would ask for 12.1 but currently getting following with 9.1

    Please tell is this expected behaviour.

    ######################################

    SETUP> read design TEST/test2.v

    // Command: read design TEST/test2.v

    // Parsing file TEST/test2.v ...

    // Error: TEST/test2.v:30 Module 'BASIC_ISO' is referenced but not defined.

    SETUP> read library -liberty test2/cell1.lib -lp

    // Command: read library -liberty test2/cell1.lib -lp

    // Parsing file test2/cell1.lib ...

    Translating Liberty file "test2/cell1.lib" to CPF file "/tmp/translated_cpf_from_libs_test2_cell1.lib_29965"

    // Warning:

    Command lib2cpf timeout after 5 second idling.

    // Error: Fail to run /remote/tools/linux/cadence/CONFRML91/bin/lib2cpf

    // Note: Read Liberty library successfully

    SETUP> report isolation cell

    // Command: report isolation cell

    // Error: Design does not exist. Please read design first.

    SETUP> report library data

    // Command: report library data

    -------------------------------------------------------------------------------------------------------

      ID Name                                   Cost    Ins    Ref    TOT   DFF  DLAT   BUF  NOT BBOX  UDP

    -------------------------------------------------------------------------------------------------------

       1 AND1                                      0      0      0      1     0     0    0     0         

       2 BASIC_ISO                                 0      0      0      1     0     0    0     0         

       3 BASIC_ISO1                                0      0      0      1     0     0    0     0         

    -------------------------------------------------------------------------------------------------------

    There are 0 cells having extra buffers

    Cost (simple: 0, complex: 0)

    #################################################

     

    #####################################

    SETUP> read design TEST/test2.v

    // Command: read design TEST/test2.v

    // Parsing file TEST/test2.v ...

    // design root module is set to 'top'

    // Warning: (RTL1.2) Variable/signal is assigned by multiple non-blocking assignments (occurrence:4)

    // Warning: (RTL2.5) Undriven net is detected (occurrence:5)

    // Warning: (RTL14) Signal has input but it has no output (occurrence:2)

    // Warning: (HRC2.2) Module/entity exists in library and design (occurrence:1)

    // Warning: There are 5 undriven nets in design

    // Note: Read VERILOG design successfully

    SETUP> report isolation cell

    // Command: report isolation cell

    // No isolation cells to be reported

    SETUP> read -cpf CPF/const2.cpf

    // Command: read -cpf CPF/const2.cpf

    // Error: Unknown command read -cpf CPF/const2.cpf.

    SETUP> read cpf CPF/const2.cpf

    // Command: read cpf CPF/const2.cpf

    // Warning: [CPF-LINT-213] create_power_domain: Internally switched power domain 'PD2' needs to specified with base domain(s). (CPF/const2.cpf:7)

    // Warning: [CPF-LINT-213] create_power_domain: Internally switched power domain 'PD3' needs to specified with base domain(s). (CPF/const2.cpf:9)

    // Warning: CPF/const2.cpf:42 Cannot find library cell matching BASIC_ISOOOO

    // Error: Serious CPF quality errors found. Please fix them before commit cpf.

    //        You can do 'read cpf' on corrected CPF files at this point without having to read the design again.

    // Error: (CPF_LS4) Level shifter cells do not exist to support voltages of crossings defined by level shifter rule. (occurrence:1)

    // Error: (CPF_RET1) No valid retention cell defined in library to support retention rule. (occurrence:1)

    // Note: (CPF_RET6) Instance defined in retention rule is not valid retention object. (occurrence:4)

    SETUP> report isolation cell

    // Command: report isolation cell

    // No isolation cells to be reported

    #######################################

     

  • Sorry, I don't remember the LP liberty results from 9.1. I do see some problems with the order of commands in your script.

    Here is a sample dofile I got from the online "web interface" documentation

    set lowpower option -netlist_style logical

    //set lowpower option -netlist_style hybrid

    //set lowpower option -netlist_style physical

    read library -append -liberty -lp <liberty files>

    read design <design_files>

    report design data

    report black box -class

    read power intent -cpf <CPF files> -post_synthesis

    //read power intent -cpf <CPF files> -post_route

    commit power intent

    analyze power domain

     

    The web interface documentation is opened via

    SETUP> set web interface on

    There are many sample dofile there.

    There are also "Rapid Adoption Kits" or RAKs located here

    http://support.cadence.com/raks 

    or for CLP:

    http://support.cadence.com/wps/mypoc/cos?uri=deeplinkmin:DocumentViewer;src=wp;q
    =ProductInformation/Functional_Verification/ApplicationPackages/Application
    PackageHome.htm

    This should point you in the right direction. I wouldn't continue working with 9.1 for LP liberty since that version was early in the LP liberty adoption phase. 

     

    -ts

  • Following your sequence, it works.

    Earlier i was doing

          lec -LPXL -verify, read design, read library -liberty <>, read cpf <>.

    With your commands

         set lowpower options -netlist_style logical ------ if not set than default should be picked.

         read commands  ---------- these should be order independent.

         report command

         commit power intent   ----- not used

        analyze power domain  ---- not used

    Do you feel this restrict the CLP to provide information as in my case?

    Please share your thoughts from better awareness. Thanks in advance.

    NTlp    

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