System for a combined error correction code and cyclic redundancy check code for a memory channel

• US 8,140,936 B2
• Filed: 01/24/2008
• Issued: 03/20/2012
• Est. Priority Date: 01/24/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Gower, Kevin C., Maule, Warren E.
• Primary Examiner(s): TRIMMINGS, JOHN P
• Application Number:
  US12/018,926
• Publication Number:
  US 20090193315A1
• Time in Patent Office: 1,517 Days
• Field of Search: None
• US Class Current: 714/758
• CPC Class Codes: G06F 11/1004 to protect a block of data words, e.g. CRC or checksum G06F11/1076 takes precedence; security arrangements for protecting computers or computer systems against unauthorized activity G06F21/00
• CPC Class Codes: H03M 13/09 Error detection only, e.g. using cyclic redundancy check [CRC] codes or single parity bit

Abstract

A memory system is provided that performs error correction at a memory device level. The memory system comprises a memory hub device integrated in the memory module and a link interface integrated in the memory hub device that provides a communication pathway between the memory hub device and an external memory controller. The link interface comprises first error correction logic integrated in the link interface that performs error correction operations on first data that is received from the external memory controller via a first memory channel to be transmitted to a set of memory devices. The first error correction logic generates a first error signal to the external memory controller in response to the first error correction logic detecting a first error in the first data. Link interface control logic integrated in the link interface controls the transmission of the first data to the set of memory devices.

Claims

1. A memory system comprising:

a memory hub device integrated in a memory module; and

a link interface integrated in the memory hub device that provides a communication pathway between the memory hub device and an external memory controller, wherein the link interface comprises;

first error checking and correcting (ECC) logic integrated in the link interface and first cyclic redundancy check (CRC) logic integrated in the link interface, wherein;

the external memory controller sends first data to the link interface using ECC code bits thereby setting the memory hub device into an ECC mode when a plurality of memory bits lanes in a first memory channel are not experiencing failures above a predetermined level,

the external memory controller sends the first data to the link interface using CRC code bits thereby setting the memory hub device into a CRC mode when at least one of the memory bit lanes in the plurality of memory bits lanes in the first memory channel is experiencing failures above the predetermined level,

responsive to receiving the first data with the ECC code bits, the first ECC logic performs error correction operations on the first data that is received from the external memory controller via the first memory channel to be transmitted to a set of memory devices,

the first ECC logic generates a first error signal to the external memory controller in response to the first ECC logic detecting a first error in the first data,

responsive to receiving the first data with the CRC code bits, the first CRC logic performs error detection operations on the first data that is received from the external memory controller via the first memory channel to be transmitted to the set of memory devices, and

the first CRC logic generates the first error signal to the external memory controller in response to the first CRC logic detecting the first error in the first data; and

link interface control logic integrated in the link interface, wherein the link interface control logic controls the transmission of the first data to the set of memory devices.

2. The memory system of claim 1, wherein the link interface further comprises:

second ECC logic integrated in the link interface and second CRC logic integrated in the link interface, wherein;

responsive to receiving second data with the ECC code bits, the second ECC logic performs error correction operations on the second data that is received from at least one of an additional memory hub device or standalone repeater hub device via a second memory channel to be transmitted to the external memory controller,

the second ECC logic generates a second error signal to the external memory controller in response to the second error correction logic detecting the second error in the second data,

responsive to receiving the second data with the CRC code bits, the second CRC logic performs error detection operations on the second data that is received from the at least one of the additional memory hub device or the standalone repeater hub device via the second memory channel to be transmitted to the external memory controller,

the second CRC logic generates the second error signal to the external memory controller in response to the second CRC logic detecting the second error in the second data, and

the link interface control logic controls the transmission of the second data to the external memory controller.

3. The memory system of claim 1, wherein the link interface further comprises:

ECC logic generation integrated in the link interface and CRC logic generation integrated in the link interface, wherein;

responsive to memory hub device operating in the ECC mode, the ECC logic generation generates error correcting code bits on third data that is received from the set of memory devices coupled to the memory hub device to be transmitted to the external memory controller,

responsive to the memory hub device operating in the CRC mode, the CRC logic generation generates CRC bits on the third data that is received from the set of memo devices coupled to the memo hub device to be transmitted to the external memory controller, and

the link interface control logic controls the transmission of the second data to the set of memory devices.

4. The memory system of claim 1, wherein the link interface sends the first data to a multiplexer and wherein the link interface control logic signals the multiplexer to transmit the first data from receive logic in response to the first error correction logic failing to detect the first error in the first data.

5. The memory system of claim 1, wherein the link interface sends the first data to a multiplexer and wherein the link interface control logic signals the multiplexer to transmit the first error signal in response to the first error correction logic detecting the first error in the first data.

6. The memory system of claim 1, wherein the first error correction logic checks the first data from the external memory controller for errors using error code bits prior to transmitting the first data to the set of memory devices.

7. The memory system of claim 2, wherein, responsive to memory hub device operating in the ECC mode, the second ECC logic checks the second data from the at least one of the additional memory hub device or the standalone repeater hub device for errors using ECC code bits prior to transmitting the second data to the external memory controller via the first memory channel and wherein, responsive to memory hub device operating in the CRC mode, the second CRC logic checks the second data from the at least one of the additional memory hub device or the standalone repeater hub device for errors using CRC code hits prior to transmitting the second data to the external memory controller via the first memory channel.

8. The memory system of claim 5, wherein the link interface sends the second data to the multiplexer prior to transmitting the second data to the external memory controller, wherein, responsive to memory hub device operating in the ECC mode, the link interface control logic signals the multiplexer to transmit the second data to the external memory controller along with the second error signal from the second ECC logic in response to the second ECC logic detecting the second error in the second data, and wherein, responsive to memory hub device operating in the CRC mode, the link interface control logic signals the multiplexer to transmit the second data to the external memory controller along with the second error signal from the second CRC logic in response to the second CRC logic detecting the second error in the second data.

9. The memory system of claim 5, wherein the link interface sends the second data to the multiplexer prior to transmitting the second data to the external memory controller, wherein, responsive to memory hub device operating in the ECC mode, the link interface control logic signals the multiplexer to transmit the second data to the external memory controller in response to the second ECC logic failing to detect the second error in the second data, and wherein, responsive to memory hub device operating in the CRC mode, the link interface control logic signals the multiplexer to transmit the second data to the external memory controller in response to the second CRC logic failing to detect the second error in the second data.

10. The memory system of claim 3, wherein, responsive to memory hub device operating, in the ECC mode, the ECC logic generation generates an error correction codeword that is added to the third data before transmitting the third data to the external memory controller via the first memory channel and wherein, responsive to memory hub device operating in the CRC mode, the CRC logic generation generates A CRC codeword that is added to the third data before transmitting the third data to the external memory controller via the first memory channel.

11. The memory system of claim 1, wherein the memory module is one of a dual in-line memory module (DIMM) or a single in-line memory module (SIMM).

12. The memory system of claim 1, wherein the memory module is part of a data processing device.

13. A data processing system, comprising:

a processor; and

a memory coupled to the processor, wherein the memory comprises one or more memory modules, each memory module comprising;

a memory hub device integrated in the memory module; and

a link interface integrated in the memory hub device that provides a communication pathway between the memory hub device and an external memory controller, wherein the link interface comprises;

first error checking and correcting (ECC) logic integrated in the link interface and first cyclic redundancy check (CRC) logic integrated in the link interface, wherein;

the external memory controller sends first data to the link interface using ECC code bits thereby setting the memory hub device into an ECC mode when a plurality of memory bits lanes in a first memory channel are not experiencing failures above a predetermined level,

the external memory controller sends the first data to the link interface using CRC code bits thereby setting the memory hub device into a CRC mode when at least one of the memory bit lanes in the plurality of memory bits lanes in the first memory channel is experiencing failures above the predetermined level,

responsive to receiving the first data with the ECC code bits, the first ECC logic performs error correction operations on the first data that is received from the external memory controller via the first memory channel to be transmitted to a set of memory devices,

the first ECC logic generates a first error signal to the external memory controller in response to the first ECC logic detecting a first error in the first data,

responsive to receiving the first data with the CRC code bits, the first CRC logic performs error detection operations on the first data that is received from the external memory controller via the first memory channel to be transmitted to the set of memory devices, and

the first CRC logic generates the first error signal to the external memory controller in response to the first CRC logic detecting the first error in the first data; and

link interface control logic integrated in the link interface, wherein the link interface control logic controls the transmission of the first data to the set of memory devices.

14. The data processing system of claim 13, wherein the link interface further comprises:

second ECC logic integrated in the link interface and second CRC logic integrated in the link interface, wherein;

responsive to receiving second data with the ECC code bits, the second ECC logic performs error correction operations on the second data that is received from at least one of an additional memory hub device or standalone repeater hub device via a second memory channel to be transmitted to the external memory controller,

the second ECC logic generates a second error signal to the external memory controller in response to the second error correction logic detecting the second error in the second data,

responsive to receiving the second data with the CRC code bits, the second CRC logic performs error detection operations on the second data that is received from the at least one of the additional memory hub device or the standalone repeater hub device via the second memory channel to be transmitted the external memory controller,

the second CRC logic generates the second error signal to the external memory controller in response to the second CRC logic detecting the second error in the second data, and

the link interface control logic controls the transmission of the second data to the external memory controller.

15. The data processing system of claim 13, wherein the link interface further comprises:

ECC logic generation integrated in the link interface and CRC logic generation integrated in the link interface, wherein;

responsive to memory hub device operating in the ECC mode, the ECC logic generation generates error correcting code bits on third data that is received from the set of memory devices coupled to the memory hub device to be transmitted to the external memory controller,

responsive to memory hub device operating in the CRC mode, the CRC logic generation generates CRC bits on the third data that is received from the set of memory devices coupled to the memory hub device to be transmitted to the external memory controller, and

the link interface control logic controls the transmission of the second data to the set of memory devices.

16. The data processing system of claim 13, wherein the link interface sends the first data to a multiplexer and wherein the link interface control logic signals the multiplexer to transmit the first data from receive logic in response to the first error correction logic failing to detect the first error in the first data.

17. The data processing system of claim 13, wherein the link interface sends the first data to a multiplexer and wherein the link interface control logic signals the multiplexer to transmit the first error signal in response to the first error correction logic detecting the first error in the first data.

18. The data processing system of claim 13, wherein the first error correction logic checks the first data from the external memory controller for errors using error code bits prior to transmitting the first data to the set of memory devices.

19. The data processing system of claim 14, wherein, responsive to memory hub device operatic in the ECC mode, the second ECC logic checks the second data from the at least one of the additional memory hub device or the standalone repeater hub device for errors using ECC code bits prior to transmitting the second data to the external memory controller via the first memory channel and wherein, responsive to memory hub device operating in the CRC mode, the second CRC logic checks the second data from the at least one of the additional memory hub device or the standalone repeater hub device for errors using CRC code bits prior to transmitting the second data to the external memory controller via the first memory channel.

20. A method for performing error correction operations in a memory module, comprising:

receiving, by a link interface in a memory hub device integrated in the memory module, an access request from an external memory controller for accessing a set of memory devices of the memory module coupled to the memory hub device, wherein the link interface error comprises error checking and correcting (ECC) logic integrated in the link interface and cyclic redundancy check (CRC) logic integrated in the link interface, wherein the external memory controller sends data to the link interface using ECC code bits thereby setting the memory hub device into an ECC mode when a plurality of memory bits lanes in a memory channel are not experiencing, failures above a predetermined level, and wherein the external memory controller sends the data to the link interface using CRC code bits thereby setting the memory hub device into a CRC mode when at least one of the memory bit lanes in the plurality of memory bits lanes in the memory channel is experiencing failures above the predetermined level;

responsive to receiving the data with the ECC code bits, performing, by the ECC logic, one or more error correction operations on the data that is received from the external memory controller via the memory channel to be transmitted to the set of memory devices, wherein the ECC logic generates an error signal to the external memory controller in response to the ECC logic detecting an error in the data;

responsive to receiving the data with the CRC code bits, performing, by the CRC logic, one or more error detection operations on the data that is received from the external memory controller via the memory channel to be transmitted to the set of memory devices, wherein the CRC logic generates the error signal to the external memory controller in response to the CRC logic detecting the error in the data; and

controlling, by link interface control logic integrated in the link interface, the transmission of the data to the set of memory devices.