Memory system and memory management method including the same

• US 8,984,237 B2
• Filed: 09/16/2011
• Issued: 03/17/2015
• Est. Priority Date: 12/06/2005
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Byun, Sung-Jae, Lee, Young Min, Lee, Yun-Tae, Hwang, Gyoo-Cheol
• Primary Examiner(s): Bradley, Matthew
• Assistant Examiner(s): TSUI, DANIEL D
• Application Number:
  US13/234,173
• Publication Number:
  US 20120011323A1
• Time in Patent Office: 1,278 Days
• Field of Search: None
• US Class Current: 711/150
• CPC Class Codes: G06F 12/0607 Interleaved addressing
• CPC Class Codes: G06F 15/177 Initialisation or configuration control processor initialisation G06F9/4405
• CPC Class Codes: G06F 9/4405 Initialisation of multiprocessor systems
• CPC Class Codes: G11C 8/16 Multiple access memory array, e.g. addressing one storage element via at least two independent addressing line groups
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A multi-processor system includes a first processor, a second processor communicable with the first processor, a first non-volatile memory for storing first codes and second codes to respectively boot the first and second processors, the first memory communicable with the first processor, a second volatile memory designated for the first processor, a third volatile memory designated for the second processor, and a fourth volatile memory shared by the first and second processors.

Claims

1. A method for sharing a memory between a first processor and a second processor, comprising:

transmitting a token from a first processor to a second processor;

accessing the memory by the second processor if the token is received, the memory being accessible by one of the first processor and the second processor at a time;

after accessing the memory, transmitting the token from the second processor to the first processor; and

accessing the memory by the first processor if the token is received,

wherein if the token is not received by the second processor, sending a request signal for the token from the second processor back to the first processor, starting a timer, and if the timer expires prior to the token being transmitted to the second processor, generating a substitute token by the second processor, and

wherein the token is transmitted between the first and second processors via a communication channel directly connected between the first and second processors, the communication channel having no intermediary token storage device between the first and second processors.

2. The method according to claim 1, further comprising:

prior to powering down the first processor, determining if the token is received by the first processor;

if the token is received by the first processor, transmitting the token from the first processor to the second processor; and

when the token is received by the second processor, initiating a power-down process of the first processor.

3. The method of claim 1, further comprising setting flag bits in the memory to track the token for access to the memory, each of the first processor and the second processor having access to the memory to check the flag bits to verify possession of the token and to request the token.

4. The method of claim 3, further comprising automatically clearing the flag bits after an access of the memory is completed.

5. The method of claim 3, further comprising prior to initiating a power-down/sleep operation, completing access to the memory by the first processor and the second processor before clearing the flag bits.

6. A multi-processor system comprising:

a first processor;

a second processor; and

a dual-port memory connected to each of the first processor and the second processor, memory cells of the dual-port memory being organized into a plurality of banks, at least one bank being accessible exclusively via a first port, at least one bank being accessible exclusive via a second port, and at feast one shared bank being accessible by both the first port and the second port,

wherein a token is passable between the first processor and the second processor over a communication channel directly connected between the first processor and the second processor, the communication channel having no intermediary token storage device between the first and second processors, a receipt of the token being indicative of accessibility of the at least one shared bank by either the first processor or the second processor,

wherein if the token is not received by the second processor, sending a request signal for the token from the second processor back to the first processor, starting a timer, and if the time expires prior to the token being transmitted to the second processor, generating a substitute token by the second processor, and

wherein the dual-port memory comprises a register having flag bits to track the token for access to the at least one shared bank, each of the first processor and the second processor having access to the register to check the flag bits to verify possession of the token and to request the token.

7. The multi-processor system of claim 6, wherein the flag bits are automatically cleared after an access of the at least one shared bank is completed.

8. The multi-processor system of claim 7, wherein prior to initiating a power-down/sleep operation, the first processor and the second processor complete their access to the shared bank before the register clears the flag bits for the token.

9. The multi-processor system of claim 6, further comprising a non-volatile memory connected to the first processor, memory cells of the non-volatile memory being organized into a plurality of blocks, each of the blocks storing respective system management information.

10. The multiprocessor system of claim 9, wherein the non-volatile memory is a flash memory.

11. The multi-processor system of claim 6, wherein dual-port memory is configured to operate in a special mode such that an exclusive bank that in a normal mode is accessible by one processor is accessible also by the other processor in the special mode.

12. The multi-processor system of claim 6, wherein the first processor is an application processor and the second processor is a modem.

13. The multi-processor system of claim 9, wherein the system management information comprises application processor boot software, modem boot software, modem operating system software, and system data.