Method and system for accelerating memory randomization

• US 8,549,367 B1
• Filed: 12/29/2010
• Issued: 10/01/2013
• Est. Priority Date: 12/29/2010
• Status: Active Grant

• Current Assignee: Cadence Design Systems Incorporated (Cadence Group)
• Original Assignee: Cadence Design Systems Incorporated (Cadence Group)
• Inventors: Sherred, Mark A.
• Primary Examiner(s): Lazaro, David
• Assistant Examiner(s): DRABIK, SARAH E
• Application Number:
  US12/981,111
• Time in Patent Office: 1,007 Days
• Field of Search: 713/1, 713/2, 713189-190, 713/300, 713/330, 713/340, 365/145, 365/230.03, 365/203, 702/85, 702/89, 714718-723, 380/2
• US Class Current: 714/718
• CPC Class Codes: G11C 2029/0405 comprising complete test loop
• CPC Class Codes: G11C 29/10 Test algorithms, e.g. memory scan [MScan] algorithms; Test patterns, e.g. checkerboard patterns
• CPC Class Codes: G11C 29/30 Accessing single arrays
• CPC Class Codes: G11C 29/36 Data generation devices, e.g. data inverters

Abstract

A method and system for randomizing memory in a functional verification test of a user design is disclosed. A random number is generated during the functional verification test. The data stored in the memory of the user design is stored. Encryption keys unique for each memory address of the memory are generated. Each encryption key for each memory address is a function of the random number and the memory address. Data in each memory address of the memory is encrypted with the encryption keys unique for each memory address. After exiting a low-power or power-off state, data in each memory address is read and decrypted using the same encryption keys. Data before and after the low-power or power-off state are compared to test memory loss.

Claims

1. A computer-implemented method for randomizing data that can be stored in a memory portion of a user design that is undergoing functional verification testing prior to manufacture using a functional verification testing system, wherein the user design can operate in a plurality of power states, including a first power state and a lower power state, comprising:

receiving a power signal indicating a change of power state of the user design undergoing functional verification to the lower power state;

generating a random number in response to the power signal;

receiving a plurality of memory addresses of a memory in the user design undergoing functional verification;

storing a first set of data in the plurality of memory addresses;

calculating a first set of encryption keys unique for each memory address of the plurality of memory addresses of the memory in the user design undergoing functional verification by performing an operation using the random number and the corresponding memory address; and

writing a second set of data to the plurality of memory addresses by encrypting the first set of data with the first set of encryption keys unique for each memory address.

2. The computer-implemented method of claim 1 further comprising:

reading the second set of data from the plurality of memory addresses of the memory after the one or more power domains is turned off or run in the lower power state;

generating a third set of data for each memory address of the memory by decrypting the second set of data using the first set of encryption keys for each memory address.

3. The computer-implemented method of claim 2 further comprising:

comparing the first set of data and the third set of data for each memory address of the plurality of memory addresses in the memory.

4. The computer-implemented method of claim 3 further comprising:

concluding that an error occurred during the steps of the writing the second set of data and/or the reading the second set of data to and/or from the plurality of memory addresses of the memory if the first set of data and the third set of data do not match.

5. The computer-implemented method of claim 1, wherein the first set of encryption keys is calculated by an exclusive OR (XOR) operation between the random number and each memory address.

6. The computer-implemented method of claim 1 further comprising:

generating a second random number in a single test cycle with a linear feedback shift register (LFSR); and

calculating a second set of encryption keys unique for each memory address of the plurality of memory addresses of the memory in the user design undergoing functional verification by performing an operation using the second random number and the corresponding memory address.

7. The computer-implemented method of claim 1, wherein the random number and the first set of encryption keys have different width.

8. The computer-implemented method of claim 7, wherein the step of generating a first set of encryption keys further comprising inverting, shifting and/or rotating selected bits in each memory address of the plurality of memory addresses based on selected set of bits from the random number.

9. The computer-implemented method of claim 7, wherein the user design models a mobile phone.

10. The computer-implemented method of claim 1, wherein the functional verification system is a hardware-based emulation system, further comprising:

programming the user design into the hardware-based emulation system that comprises a plurality of emulation resources.

11. The computer-implemented method of claim 1, wherein the memory in the user design undergoing functional verification testing is programmed into a hardware-based emulation system that comprises a plurality of emulation resources, and wherein the hardware-based emulation system is the functional verification testing system.

12. A non-transitory computer-readable storage medium having stored thereon a plurality of instructions, said plurality of instructions when executed by a computer, cause said computer to perform:

generating a random number in response to a power signal during a functional verification test of a user design undergoing functional verification, wherein the functional verification test is performed prior to manufacture using a functional verification testing system, and wherein the user design can operate in a plurality of power states, including a first power state and a lower power state;

receiving the power signal indicating a change of power state of the user design undergoing functional verification to the lower power state;

receiving a plurality of memory addresses of a memory in the user design;

storing a first set of data in the plurality of memory addresses;

calculating a first set of encryption keys unique for each memory address of the plurality of memory addresses of the memory in the user design undergoing functional verification by performing an operation using the random number and the corresponding memory address; and

writing a second set of data to the plurality of memory addresses by encrypting the first set of data with the first set of encryption keys unique for each memory address.

13. The non-transitory computer-readable storage medium of claim 12 having stored thereon a plurality of instructions, said plurality of instructions when executed by a computer, cause said computer to further perform:

reading the second set of data from the plurality of memory addresses of the memory after the one or more power domains is turned off or run in the lower power state;

generating a third set of data for each memory address of the memory by decrypting the second set of data using the first set of encryption keys for each memory address.

14. The non-transitory computer-readable storage medium of claim 13 having stored thereon a plurality of instructions, said plurality of instructions when executed by a computer, cause said computer to further perform:

comparing the first set of data and the third set of data for each memory address of the plurality of memory addresses in the memory.

15. The non-transitory computer-readable storage medium of claim 14 having stored thereon a plurality of instructions, said plurality of instructions when executed by a computer, cause said computer to further perform:

concluding that an error occurred during the steps of the writing the second set of data and/or the reading the second set of data to and/or from the plurality of memory addresses of the memory if the first set of data and the third set of data do not match.

16. The non-transitory computer-readable storage medium of claim 12, wherein the first set of encryption keys is calculated by an exclusive OR (XOR) operation between the random number and each memory address.

17. The non-transitory computer-readable storage medium of claim 12 having stored thereon a plurality of instructions, said plurality of instructions when executed by a computer, cause said computer to further perform:

generating a second random number in a single test cycle with a linear feedback shift register (LFSR); and

calculating a second set of encryption keys unique for each memory address of the plurality of memory addresses of the memory in the user design undergoing functional verification by performing an operation using the second random number and the corresponding memory address.

18. The non-transitory computer-readable storage medium of claim 12, wherein the random number and the first set of encryption keys have different width.

19. The non-transitory computer-readable storage medium of claim 18, wherein the step of generating a first set of encryption keys further comprising inverting, shifting and/or rotating selected bits in each memory address of the plurality of memory addresses based on selected set of bits from the random number.

20. The non-transitory computer-readable storage medium of claim 18, wherein the user design models a mobile phone.

21. The non-transitory computer-readable storage medium of claim 12 having stored thereon a plurality of instructions, said plurality of instructions when executed by a computer, cause said computer to further perform:

programming the user design into a hardware-based emulation system that comprises a plurality of emulation resources, and wherein the hardware-based emulation system is the functional verification testing system.

22. The non-transitory computer-readable storage medium of claim 12, wherein the memory in the user design undergoing functional verification testing is programmed in a hardware-based emulation system that comprises a plurality of emulation resources, and wherein the hardware-based emulation system is the functional verification testing system.

23. A system for randomizing data that can be stored in a memory portion of a user design that is undergoing functional verification testing prior to manufacture using a functional verification testing system, wherein the user design can operate in a plurality of power states, including a first power state and a lower power state, the system comprising:

a random number generator for generating a random number in response to a power state signal indicating a change of power state of the user design undergoing functional verification to the lower power state, wherein the random number generator receives the power state signal from the user design or from a computer performing the functional verification testing;

a memory in a user design undergoing functional verification having a plurality of memory addresses;

an encrypter for calculating based on the power state signal a first set of encryption keys unique for each memory address of the plurality of memory addresses by performing an operation using the random number and the corresponding memory address of the memory in the user design undergoing functional verification;

an encrypting circuit for encrypting data in the plurality of memory addresses using the first set of encryption keys; and

a decrypting circuit for decrypting data read from the plurality of memory addresses using the first set of encryption keys,

wherein each encryption key of the first set of encryption keys are unique for each memory address.

24. The system for randomizing data of claim 23 wherein the user design and the memory in the user design is programmed in a hardware-based emulation system that comprises a plurality of emulation resources, and wherein the hardware-based emulation system is the functional verification testing system.