Communication using integrated circuit interconnect circuitry

• US 9,288,258 B2
• Filed: 10/11/2011
• Issued: 03/15/2016
• Est. Priority Date: 10/12/2010
• Status: Active Grant

• Current Assignee: Arm Limited (SoftBank Group Corp.)
• Original Assignee: Arm Limited (SoftBank Group Corp.)
• Inventors: Mace, Timothy Charles, Rose, Andrew Christopher
• Primary Examiner(s): Jacobs, Lashonda
• Application Number:
  US13/825,190
• Publication Number:
  US 20130219004A1
• Time in Patent Office: 1,617 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 15/7825 Globally asynchronous, locally synchronous, e.g. network on chip
• CPC Class Codes: G06F 15/7842 on one IC chip (single chip microcontrollers)
• CPC Class Codes: H04L 12/40084 Bus arbitration
• CPC Class Codes: H04L 12/46 Interconnection of networks
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 67/10 in which an application is distributed across nodes in the network software deployment G06F8/60; multiprogramming arrangements G06F9/46

Abstract

An integrated circuit comprising multiple master units and multiple slave units connected via interconnect circuitry utilizes token based node-to-node communication flow management within the interconnect circuitry with a network node requesting a token and receiving a token signal before it asserts its communication signals onto a physical communication link shared between multiple virtual networks.

Claims

1. An integrated circuit comprising:

a plurality of master units configured to generate communication transactions;

interconnect circuitry coupled to said plurality of master units and configured to carry said communication transactions; and

one or more slave units coupled to said interconnect circuitry and configured to respond to said communication transactions;

wherein

said interconnect circuitry is configured to provide a plurality of virtual networks, each virtual network connecting at least one of said plurality of master units to at least one of said one or more slave units and including a plurality of network nodes, at least two of said plurality of virtual networks being overlapping virtual networks having an overlapped portion that shares a physical communication link between at least two of said plurality of network nodes; and

at least network nodes within said overlapped portion perform node-to-node token based communication flow management whereby;

(i) before asserting communication signals corresponding to a communication transaction with a target slave unit via one of said overlapping virtual networks, at least network nodes within said overlapped portion are configured to assert a token request upon said overlapping virtual network to request a token signal for said overlapping virtual network from a next network node downstream within said overlapping virtual network toward said target slave unit and not to assert said communication signals upon said physical communication link shared with another overlapping virtual network until said token signal is received; and

(ii) said next network node receiving said token request blocks return of said token signal until said next network node is ready to receive said communication signals.

2. An integrated circuit as claimed in claim 1, wherein said next network node is ready to receive said communication signals when one of:

(i) said next network node is able to store said communication signal and to trigger clearing of said communication signals from said overlapped portion such that said physical communication link shared with another overlapping virtual network is made available for further use; and

(ii) said next network node has received a token signal from a further network node downstream within said overlapping virtual network indicating said further network node is ready to receive said communication signals.

3. An integrated circuit as claimed in claim 1, wherein a master unit within said overlapping virtual network is one of said network nodes and generates said token request.

4. An integrated circuit as claimed in claim 3, wherein a network node within said overlapping virtual network between said master unit and said target slave unit forwards said token request toward said slave unit.

5. An integrated circuit as claimed in claim 1, wherein a network node within said overlapping virtual network between said master unit and said target slave unit includes storage elements configured to store said communication signals, said network node responding to receipt of said token request to return said token signal if said storage elements are available to store said communication signals within said storage elements.

6. An integrated circuit as claimed in claim 5, wherein network nodes within said overlapped portion include a plurality of sets of storage elements each dedicated to storing communication signals for a respective overlapping virtual network.

7. An integrated circuit as claimed in claim 6, wherein token requests and token signals passing between said network nodes within said overlapped portion are pipeline processed.

8. An integrated circuit as claimed in claim 1, wherein said token request and said token signal provide handshake communication control.

9. An integrated circuit as claimed in claim 1, wherein said target slave unit within said overlapping virtual network is one of said network nodes and generates said token signal when ready to receive said communication signals.

10. An integrated circuit as claimed in claim 1, wherein congestion upon one of said overlapping virtual networks that blocks return of said token signal does not block communication via said another overlapping virtual network.

11. An integrated circuit as claimed in claim 1, wherein a graphics processing unit and a general purpose processor are master units connected via different overlapping virtual networks to a memory controller being a slave device.

12. An integrated circuit as claimed in claim 1, comprising respective overlapping virtual networks for carrying write address signals and for carrying write data.

13. An integrated circuit as claimed in claim 12, wherein at least network nodes asserting a token request upon an overlapping virtual network for carrying write address signals also assert a token request upon an overlapping virtual network for carrying corresponding write data signals.

14. An integrated circuit as claimed in claim 13, wherein if said communication transaction is a write burst request having a plurality of write data beats, then a token request is asserted for each of said write data beats.

15. An integrated circuit as claimed in claim 13, wherein in response to a sequence of communication transactions token signals for said write data signals are returned in a same order with respect to said sequence as token signals for said write address signals.

16. An integrated circuit as claimed in claim 1, wherein at least one of said plurality of master units is a token-pre-fetching master unit configured to issue a token request before a corresponding communication transaction is ready to issue, thereby reducing latency associated with said communication transaction.

17. An integrated circuit as claimed in claim 16, wherein a network node configured to receive a token request from a token-pre-fetching master unit includes at least one set of storage elements dedicated to storing communication signals for said token-pre-fetching master unit.

18. An integrated circuit as claimed in claim 17, wherein a token-pre-fetching master unit can pre-fetch a maximum of one token signal.

19. An integrated circuit as claimed in claim 1, comprising a plurality of slave units connected to said overlapped portion.

20. An integrated circuit as claimed in claim 19, wherein a final network node within said overlapped portion and connected to said plurality of slave units uses a memory address associated with said communication transaction to route said token request to one of said slave units mapped to said memory address.

21. An integrated circuit as claimed in claim 20, wherein said final network node issues separate token requests to each of said plurality of slave units an receives separate token signals from each of said plurality of slave units.

22. An integrated circuit as claimed in claim 1, wherein said communication transactions have an associated priority value and network nodes within said overlapped portion are responsive to priority values associated with different communication transactions to arbitrate access to said physical communication link.

23. An integrated circuit comprising:

a plurality of master means for generating communication transactions;

interconnect means for carrying said communication transactions, said interconnect means being coupled to said plurality of master means; and

one or more slave means for responding to said communication transactions, said one or more slave means being coupled to said interconnect circuitry;

wherein

said interconnect means is configured to provide a plurality of virtual networks, each virtual network connecting at least one of said plurality of master means to at least one of said one or more slave means and including a plurality of network nodes, at least two of said plurality of virtual networks being overlapping virtual networks having an overlapped portion that shares a physical communication link between at least two of said plurality of network nodes; and

at least network nodes within said overlapped portion perform node-to-node token based communication flow management whereby;

(i) before asserting communication signals corresponding to a communication transaction with a target slave means via one of said overlapping virtual networks, at least network nodes within said overlapped portion are configured to assert a token request upon said overlapping virtual network to request a token signal for said overlapping virtual network from a next network node downstream within said overlapping virtual network toward said target slave means and not to assert said communication signals upon said physical communication link shared with another overlapping virtual network until said token signal is received; and

(ii) said next network node receiving said token request blocks return of said token signal until said next network node is ready to receive said communication signals.

24. A method of communication using an integrated circuit, said method comprising the steps of:

generating communication transactions with a plurality of master units;

carrying said communication transactions with interconnect circuitry coupled to said plurality of master units; and

responding to said communication transactions with one or more slave units coupled to said interconnect circuitry;

said method further comprising the steps of;

providing a plurality of virtual networks, each virtual network connecting at least one of said plurality of master units to at least one of said one or more slave units and including a plurality of network nodes, at least two of said plurality of virtual networks being overlapping virtual networks having an overlapped portion that shares a physical communication link between at least two of said plurality of network nodes; and

performing node-to-node token based communication flow management whereby;

(i) before asserting communication signals corresponding to a communication transaction with a target slave unit via one of said overlapping virtual networks, at least network nodes within said overlapped portion assert a token request upon said overlapping virtual network to request a token signal for said overlapping virtual network from a next network node downstream within said overlapping virtual network toward said target slave unit and do not assert said communication signals upon said physical communication link shared with another overlapping virtual network until said token signal is received; and

(ii) said next network node receiving said token request blocks return of said token signal until said next network node is ready to receive said communication signals.