DIRECT DATA TRANSFER BETWEEN SLAVE DEVICES

• US 20090259785A1
• Filed: 04/11/2008
• Published: 10/15/2009
• Est. Priority Date: 04/11/2008
• Status: Active Grant

• Current Assignee: Western Digital Israel Limited (Western Digital Corporation)
• Original Assignee: SanDisk IL Ltd. (Western Digital Corporation)
• Inventors: Pikman, Yaron, Perry, Nir
• Granted Patent: US 7,809,873 B2
• Time in Patent Office: Days
• US Class Current: 710/110
• CPC Class Codes: G06F 13/1684 using multiple buses
• CPC Class Codes: G06F 13/28 using burst mode transfer, e.g. direct memory access DMA, cycle steal G06F13/32 takes precedence

Abstract

In one aspect, a method of transferring data over a plurality of communication lines is described. A first command is sent from a master device coupled with the communication lines to a first destination slave device coupled with the communication lines instructing the first destination slave device to listen to and write data from the communication lines starting at a first time. A second command is sent from the master device to a second source slave device coupled with the communication lines instructing the second source slave device to read and output first data onto the communication lines starting at or after the first time. In this way, the first data output from the second source slave device beginning at the first time is stored by the first destination slave device beginning at the first time without requiring first transferring the data to the master device or any other device.

Claims

1. A method of directly transferring data between a first and a second device coupled with each other and with a master device with one or more communication lines, comprising:

instructing the first device by the master device to listen to the one or more communication lines; and

transmitting data onto the one or more communication lines by the second device, wherein the data transmitted onto the one or more communication lines by the second device is received by the first device without further intervention by the master device.

2. A method as recited in claim 1, wherein the master device is a host device and wherein the first and second slave devices are local storage devices.

3. A method as recited in claim 1, wherein the master device, first device and second device communicate according to the Secured Digital (SD) protocol.

5. A method as recited in claim 3, wherein the master device is a host device and wherein the first and second slave devices are local storage devices.

6. A method as recited in claim 3, wherein at least one of the first and second slave devices is a removable device configured for ready removal from and addition to various communication lines.

7. A method as recited in claim 3, wherein the communication lines form a shared bus.

8. A method as recited in claim 3, wherein the first and second slave devices are two of a plurality of addressable devices arranged in a daisy chain configuration such that each of the addressable devices is connected with at least one neighboring device via one or more of the communication lines, wherein each device is connected with no more than two immediately adjacent neighboring devices, and wherein each device other than the last device in the chain passes communications, including commands, that are not targeted to itself to the next device in the chain via the communication lines that connect neighboring devices with one another.

9. A method as recited in claim 3, wherein the master device, first slave device and second slave device communicate according to the Secured Digital (SD) protocol.

10. A method as recited in claim 3, wherein the first slave device is unaware that the first data is coming directly from the second slave device and not from the master device.

11. A method as recited in claim 3, wherein the first command instructs the first device to listen to and write data from the communication lines for a first prescribed duration beginning at the first time.

12. A method as recited in claim 3, wherein the second command instructs the second slave device to output data onto the communication lines for a second prescribed duration beginning at or after the first time.

13. A method as recited in claim 3, further comprising sending a third command from the master device to the second slave device that instructs the second slave device to stop outputting data onto the communication lines at a second time.

14. A method as recited in claim 13, further comprising sending a fourth command from the master device to the first slave device that instructs the first slave device to stop listening to the communication lines at or after the second time.

15. A method as recited in claim 3, wherein the first command is multicast or broadcast to multiple slave devices including the first slave device substantially simultaneously and wherein the first command instructs at least a plurality of the multiple slave devices to listen to and write data from the communication lines starting at the first time such that the first data can be stored by the plurality of the multiple slave devices substantially simultaneously.

4. A method of transferring data over a plurality of communication lines, comprising:

sending a first command from a master device coupled with the communication lines to a first destination slave device coupled with the communication lines, the first command instructing the first destination slave device to listen to and write data from the communication lines starting at a first time; and

sending a second command from the master device to a second source slave device coupled with the communication lines, the second command instructing the second source slave device to read and output first data onto the communication lines starting at or after the first time;

wherein the first data output from the second source slave device beginning at the first time is stored by the first destination slave device beginning at the first time without requiring first transferring the first data to the master device or any other storage device.

16. A method of communicating over a plurality of communication lines, comprising:

sending a first command from a master device coupled with the communication lines to a first slave device coupled with the communication lines, the first command instructing the first slave device to listen to the communication lines starting at a first time; and

sending a second command from the master device to a second slave device coupled with the communication lines, the second command instructing the second slave device to output a third communication onto the communication lines starting at or after the first time;

wherein the third communication output from the second slave device is read by the first slave device beginning substantially at the first time without requiring first transferring the third communication to the master device or any other device.

17. A method as recited in claim 16, wherein the at least one of the first and second slave devices is a network device.

18. A method as recited in claim 17, wherein the network device serves a network bridge between the bus and a remote network.

19. A method as recited in claim 18, wherein the first slave device is a network card, the method further comprising outputting a fourth communication onto the remote network in response to the third communication.

20. A method as recited in claim 18, wherein the second slave device is a network card and wherein the third communication includes data received from the remote network by the second slave device.

21. A system, comprising:

a first addressable destination slave device configured to store data;

a second addressable source slave device configured to store data and including first data stored therein;

a master device arranged to manage the first and second slave devices; and

a plurality of communication lines that couple the master device and at least each of the first and second slave devices; and

wherein the master device is further arranged to send a first command to the first slave device instructing the first slave device to listen to and write data from the communication lines beginning at a first time and a second command to the second slave device instructing the second slave device to read and output the first data onto the communication lines beginning at or after the first time, such that the first data is transferred from the second source slave device to the first destination slave device without requiring first transferring the first data to the master device or any other storage device.

22. A system as recited in claim 21, wherein the master device is a host device and wherein the first and second slave devices are local storage devices.

23. A system as recited in claim 21, wherein at least one of the first and second slave devices is a removable device configured for ready removal from and addition to various communication lines.

24. A system as recited in claim 21, wherein the communication lines form a shared bus.

25. A system as recited in claim 21, wherein the first and second slave devices are two of a plurality of addressable devices arranged in a daisy chain configuration such that each of the addressable devices is connected with at least one neighboring device via one or more of the communication lines, wherein each device is connected with no more than two immediately adjacent neighboring devices, and wherein each device other than the last device in the chain passes communications, including commands, that are not targeted to itself to the next device in the chain via the communication lines that connect neighboring devices with one another.

26. A system as recited in claim 21, wherein the master device, first slave device and second slave device communicate according to the Secured Digital (SD) protocol.

27. A system as recited in claim 21, wherein the first slave device is unaware that the first data is coming directly from the second slave device and not from the master device.

28. A system as recited in claim 21, wherein the first command instructs the first device to listen to and write data from the communication lines for a first prescribed duration beginning at the first time.

29. A system as recited in claim 21, wherein the second command instructs the second slave device to read and output data onto the communication lines for a second prescribed duration beginning at or after the first time.

30. A system as recited in claim 21, wherein the master device is further arranged to send a third command to the second slave device that instructs the second slave device to stop outputting data onto the communication lines at a second time.

31. A system as recited in claim 30, wherein the master device is further arranged to send a fourth command to the first slave device that instructs the first slave device to stop listening to the communication lines at or after the second time.

32. A system as recited in claim 21, wherein the first command is multicast or broadcast to multiple slave devices including the first slave device substantially simultaneously and wherein the first command instructs at least a plurality of the multiple slave devices to listen to and write data from the communication lines starting at the first time such that the first data can be stored by the plurality of the multiple slave devices substantially simultaneously.

33. A system, comprising:

a first addressable slave device;

a second addressable slave device;

a master device arranged to manage the first and second slave devices; and

a plurality of communication lines that couple the master device and at least each of the first and second slave devices; and

wherein the master device is further arranged to send a first command to the first slave device instructing the first slave device to listen to the communication lines beginning at a first time and a second command to the second slave device instructing the second slave device to output a third communication onto the communication lines beginning at or after the first time, wherein the third communication output from the second slave device is read by the first slave device beginning substantially at the first time without requiring first transferring the third communication to the master device or any other device.

34. A system as recited in claim 33, wherein the at least one of the first and second slave devices is a network device.

35. A system as recited in claim 34, wherein the network device serves as a network bridge between the bus and a remote network.

36. A system as recited in claim 35, wherein the first slave device is a network card, and wherein the first slave device responds to the third communication by outputting a fourth communication onto the remote network.

37. A system as recited in claim 35, wherein the second slave device is a network card and wherein the third communication includes data received from the remote network by the second slave device.