JP2007020110A - Bus system and its path determination method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily determine a path of a bus system including a ring bus and a bypass path. <P>SOLUTION: Based on identification information for identifying a plurality of bus adapters and receiving side identification information for identifying a receiving side bus adapter, a path is determined at a branching point of a ring bus and a bypass path. Then, communication is performed between an arbitrary transmitting side bus adapter and the receiving side bus adapter via the determined path. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a bus system, and more particularly to a bus system suitable for a system-on-chip (SoC) and a route determination method thereof.

  Conventionally, a bus system using a ring bus having a bypass path and a method for determining a data transmission path (for example, see Patent Document 1) have been proposed. The technique described in Patent Document 1 is effective in solving the wire delay problem when connecting a large number of functional blocks, particularly in a system-on-chip.

Also, ARPANET developed at the University of California at Berkeley is a technology for realizing data transfer between any two points on the network.
JP 2003-218891 A

  The present invention provides a bus system and a route determination method on a network for realizing a flexible data path configuration by connecting a large number of functional blocks constituting a system-on-chip via a network.

  Such bus systems often have bypass paths to improve performance. Patent Document 1 describes that the route is determined by an arbiter bus selection table. In ARPANET, it is described that a route is determined by a routing table of a router.

  In a general computer network, there may be a change in components such as a terminal being connected to or disconnected from the network. In addition, a certain route may become normal due to equipment failure. For this reason, a flexible route determination method is required.

  However, in the case of a normal system-on-chip, since the functional blocks are determined at the time of design, even in a reconfigurable logic circuit, the number of functional blocks and the connection form are determined when the configuration information is determined. Therefore, there is no need to determine a route corresponding to frequent configuration changes.

  The present invention has been made to solve the above-described problems, and an object thereof is to easily determine a route of a bus system having a ring bus and a bypass route.

  Another object of the present invention is to provide a simple route determination method based on a comparison with a threshold value of a reception side address or a bit pattern of a reception side address, instead of using a table reference, by utilizing that the network configuration is fixed. .

  The present invention provides a ring bus to which a plurality of bus adapters are connected and at least one of the ring buses that connects two of the plurality of bus adapters directly or via one or more other bus adapters. In a bus system having a bypass path, a path at a branch point between the ring bus and the bypass path based on identification information for identifying the plurality of bus adapters and reception side identification information for identifying a bus adapter on the reception side And a communication unit that performs communication between an arbitrary transmission-side bus adapter and a reception-side bus adapter on the route determined by the route determination unit.

  The present invention also provides a ring bus to which a plurality of bus adapters are connected and at least one ring bus that connects two of the plurality of bus adapters directly or via one or more other bus adapters. A path determination method for a bus system having an external bypass path, wherein the ring bus and the ring bus are based on identification information for identifying the plurality of bus adapters and reception side identification information for identifying a bus adapter on the reception side. A route determination step for determining a route at a branch point with the bypass route, and a communication step for performing communication between an arbitrary transmission-side bus adapter and a reception-side bus adapter on the route determined in the route determination step. It is characterized by.

  According to the present invention, a route can be easily determined at a branch point with a simple configuration.

  The best mode for carrying out the invention will be described below in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a block diagram illustrating a configuration example of a bus system according to the first embodiment. As shown in FIG. 1, the bus system 100 includes a ring bus 101 and a bypass path 109. Here, the ring bus 101 is a bus having a unidirectional transmission function connecting a plurality of bus adapters 102 to 106.

  On the other hand, the bypass path 109 is a bus having a unidirectional transmission function from the bus adapter 104 to the bus adapter 102 via the bus adapter 107. The function blocks 108a to 108f each have a predetermined function such as arithmetic processing, and are connected to the bus system by the respective bus adapters 102 to 107.

Here, it is assumed that the bus system 100 is controlled by the following arbitrary method.
(1) A method that enables transmission when transmission permission is obtained from the bus arbiter 109 (2) A method that performs flow control with signals on the bus (3) Each bus adapter detects a collision as in Ethernet (registered trademark) A method of resending in the event of a collision with a means.

  FIG. 2 is a diagram illustrating a format of data communicated between the bus adapters in the first embodiment. As shown in FIG. 2, in the bus system 100, communication between any two points is performed by a packet 200 including a header portion 202 including a receiving side identification number field 201 and a body portion 203 corresponding to net communication contents. Done.

  In addition to the receiving side identification number field 201, the header part 202 may have fields for storing information such as a transmitting side identification number and a packet length, as in the example of the Internet protocol (IP). .

  Next, the configuration of the bus adapters 102 to 107 for connecting the functional blocks 108a to 108f to the ring bus 101 or the bypass path 109 of the bus system 100 will be described with reference to FIG.

  The bus adapters 103, 105, and 106 have the same configuration as that of the bus adapter 107 except that the connection destination is the ring bus 101 or the bypass path 109. Therefore, the bus adapters 102, 104, and 107 will be described. To do.

  Further, the configuration shown in FIG. 3 is a case where a method is used in which transmission is possible when transmission permission is obtained from the bus arbiter 109 of (1) above. In the case of other methods, for example, when the flow control method is used with the above-mentioned signal (2) on the bus, a control unit may be provided in the bus adapter, or the bus arbiter may perform the flow control.

  FIG. 3 is a diagram illustrating a configuration example of the bus adapters 102, 104, and 107 according to the first embodiment. The bus adapter 102 includes a multiplexer 301 and a decoder 302, and outputs any one of the three data input to the bus adapter 102 to the bus adapter 103 based on at least a selection signal and a permission signal from the bus arbiter 109. The three input data are data output from the bus adapter 106 via the ring bus 101, data output from the bus adapter 107 via the bypass path 109, and data output from the functional block 108b. is there.

  The bus adapter 107 includes a multiplexer 303 and a decoder 304, and outputs one of the two data input to the bus adapter 107 to the bus adapter 102 based on at least a selection signal and a permission signal from the bus arbiter 109. . Note that the two input data are data output from the bus adapter 104 via the bypass path 109 and data output from the functional block 108f.

  The bus adapter 104 includes decoders 305 and 306, and outputs one of the two data input to the bus adapter 104 to the bus adapter 107 or 105 based on at least a selection signal and a permission signal from the bus arbiter 109. To do. That is, the data is output to either the bus adapter 107 connected by the bypass path 109 or the bus adapter 105 connected by the ring bus 101. Here, the two input data are data output from the bus adapter 103 via the ring bus 101 and data output from the functional block 108c.

  In the above configuration, processing for assigning an identification number to each of the bus adapters 402 to 407 and determining a route based on the value of the receiving side identification number included in the packet received by each bus adapter will be described.

  FIG. 4 is a diagram illustrating an example in which identification numbers are assigned to the respective bus adapters 402 to 407. In the example shown in FIG. 4, functional blocks and arbiters connected to the respective bus adapters 402 to 407 are omitted.

  Each of the bus adapters 402 to 407 passes the contents of the packet to the connected functional block if the received identification number field 201 matches the assigned identification number in the received packet. Transfer to the bus adapter.

  The bus adapter 404, which is a branch point between the ring bus 401 and the bypass route 409, determines the route for transferring the packet as follows. That is, the value of the receiving side identification number is compared with a threshold value (“5” in the example shown in FIG. 4), and if it is less than the threshold value, the ring bus 401 is selected as the route, and if the threshold value is exceeded, the bypass route 409 is selected. To do.

  As described above, communication between arbitrary bus adapters can be performed by determining a route based on the value of the receiving side identification number included in the packet received by each bus adapter.

  The bus adapter 402 may have two types of identification numbers: an identification number “1” corresponding to the ring bus 401 and an identification number “7” corresponding to the bypass path 409. Thus, for example, when “1” is designated as the reception side identification number when performing communication from the bus adapter 403 to the bus adapter 402, the ring bus 401 is determined as a route. When “7” is designated as the receiving side identification number, the bypass route 409 is determined as the route. Therefore, it is possible to select the route determination in this way.

  FIG. 5 is a diagram illustrating an example in which another identification number different from that in FIG. 4 is assigned. In the example shown in FIG. 5, the route selection in the bus adapter 504 is the ring bus 501 if the most significant receiving identification number is “0”, and if the most significant receiving identification number is “1”. A bypass path 509 may be used.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described in detail with reference to the drawings.

  FIG. 6 is a block diagram illustrating a configuration example of a bus system according to the second embodiment. In FIG. 6, the outer peripheral portion passes through the ring bus 601, and the bypass paths 602-605 pass through the inside. The bypass path 604 branches off from the bus adapter 606 on the bypass path 303.

  As described above, in a complex bus system including a plurality of branches, an identification number and a threshold for route selection are assigned by the procedure shown in FIG. Hereinafter, the processing for determining the threshold for route selection shown in FIG. 7 will be described using the bus system shown in FIG. 6 as an example. The identification number is a 6-bit numerical value.

  First, in steps S701 and S702, an identification number is assigned on the ring bus. As a result, for example, as shown in FIG. 8, it is assumed that an identification number is assigned.

  Next, in step S703, it is determined whether or not assignment of identification numbers has been completed for all bus adapters of the bus system. Here, since no identification number is assigned to the bus adapter on the bypass system, the process proceeds to step S703. In step S703, the branch point to which the identification number is not yet assigned, for example, the bus adapter 803 is excluded, and the branch point having the largest identification number is selected from the branch points having the identification number. In the example shown in FIG. 8, the bus adapter 802 having the largest identification number is selected from the bus adapters 801 (identification number 000100) and 802 (identification number 000101).

  Next, in step S705, the bypass path 804 branched from the bus adapter 802 at the branch point selected in step S704 is selected. In step S <b> 706, “000111” is set as the threshold for the bypass route 804.

  Next, in step S707, an identification number 001000 is assigned to the bus adapter 805 on the bypass path 804. Then, the process returns to step S703 described above.

  Here, in step S703, since an identification number is not assigned to the bus adapters on the bypass paths 806 and 807 branched from the bus adapter 801, the process proceeds to step S704. In step S704, the only bus adapter 801 to which an identification number is assigned at the present time and a bus adapter without an identification number is connected on the bypass destination bypass path is selected.

  Next, in step S705, there are bypass paths 806 and 807 branched from the bus adapter 801. Since the bypass path 806 further branches into the bypass paths 806a and 806b in the bus adapter 803, there are bypass paths 806a, 806b, and 807 as candidate paths. Any one may be selected, but in this example, the bypass path 806a is selected. In step S 706, “001000” is set as the threshold for the bypass route 806.

  Next, in step S707, an identification number is assigned to the bus adapter 803 on the bypass path 806. In this example, “001001” to “001111” are missing numbers and “010000” is assigned. This is because the path can be determined by the upper 3 bits as will be described later. Further, an identification number “010001” is assigned to the next bus adapter 808 on the selected bypass path 806a. Then, the process returns to step S703 described above.

  Here, in step S703, since the identification numbers are not assigned to the bypass adapters 807 and 810 on the bypass path 807 branched from the bus adapter 801 and the bypass path 806b branched from the bus adapter 803, the process proceeds to step S704. In step S704, the bus adapter 803 having a larger identification number is selected from the bus adapter 803 (identification number 010000) that is the branch source of the bypass path 806b and the bus adapter 801 (identification number 000100) that is the branch source of the bypass path 807. select.

  Next, in step S705, the bypass path 806b branched from the bus adapter 803 is selected. In step S706, “010001” is set as the threshold for the bypass route 806b.

  Next, in step 707, an identification number is assigned to the bus adapter 809 on the bypass path 806b. In this example, “010010” to “010111” are missing numbers and “011000” is assigned. Then, the process returns to step S703 described above.

  Here, in step S703, since an identification number is not assigned to the bus adapter 810 on the bypass path 807 branched from the bus adapter 801, the process proceeds to step S704. In step S704, the only remaining branch source bus adapter 801 (identification number 000100) is selected.

  In step S705, the bypass path 807 branched from the bus adapter 801 is selected. In step S706, “011000” is set as the threshold value for the bypass route 807.

  Next, in step S707, an identification number is assigned to the bus adapter 810 on the bypass path 807. In this example, “011001” to “011111” are omitted, and “100000” is assigned. And it returns to above-mentioned step S703, and since the identification number was allocated to all the bus adapters, a process is complete | finished.

  With the above processing, as shown in FIG. 9, an identification number and a route selection threshold can be determined for each bus adapter.

  Hereinafter, the determination of the route in FIG. 9 will be described.

  Since the bus adapter 901 has three branches, it has two threshold values (001000, 011000). The route of each packet is determined as follows.

  When the receiving side identification number is less than or equal to the first threshold (001000), the route 904 exceeds the first threshold, and when it is less than the second threshold (011000), the route 905 exceeds the second threshold. A route 906 is obtained.

  A branch in the bus adapter 902 has a threshold value 000111. The path of each packet is a path 907 when the receiving side identification number is equal to or smaller than the threshold, and a path 908 when the threshold is exceeded.

  A branch in the bus adapter 903 has a threshold value 010001. The path of each packet is a path 909 when the receiving side identification number is less than or equal to the threshold, and a path 910 when the threshold is exceeded.

  With the configuration described above, each packet can reach the bus adapter indicated by the receiving side identification number.

  Further, instead of the method of determining the route by comparing with the threshold value shown in FIG. 9, as shown in FIG. 10, the route is determined by the value of one or more specific bits in the receiving side identification number of each packet. It is also possible to perform.

  The unidirectional bus has been described above as an example. However, since the bidirectional bus can be regarded as a combination of the unidirectional bus and the bypass route, the present invention is also applied to the bidirectional bus. Is possible.

  In addition, as in the Internet protocol, a plurality of networks are connected, and the upper bit group of the bus adapter identification number is used for identifying the network, and the lower bit group is used for identifying the bus adapter in the network. good. As a result, it is possible to construct a network having a more complicated configuration.

  A feature of the network within the system on chip is that the configuration is fixed at the time of design and there is no need to consider changes. The present invention makes use of this feature to simplify the route determination procedure and to compare the receiving side identification number with a certain threshold value, or to make a determination based on only a part of the bits of the receiving side identification number.

  As a result, the circuit scale for path determination can be reduced, and the path determination speed can be increased.

  Even if the present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), it is applied to an apparatus (for example, a copier, a facsimile machine, etc.) composed of a single device. It may be applied.

  In addition, a recording medium in which a program code of software for realizing the functions of the above-described embodiments is recorded is supplied to the system or apparatus, and the computer (CPU or MPU) of the system or apparatus stores the program code stored in the recording medium. Read and execute. It goes without saying that the object of the present invention can also be achieved by this.

  In this case, the program code itself read from the recording medium realizes the functions of the above-described embodiment, and the recording medium storing the program code constitutes the present invention.

  As a recording medium for supplying the program code, for example, a floppy (registered trademark) disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like is used. be able to.

  In addition, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also the following cases are included. That is, when the OS (operating system) running on the computer performs part or all of the actual processing based on the instruction of the program code, and the functions of the above-described embodiments are realized by the processing.

  Further, the program code read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. After that, based on the instruction of the program code, the CPU of the function expansion board or function expansion unit performs part or all of the actual processing, and the function of the above-described embodiment is realized by the processing. Needless to say.

It is a block diagram which shows the structural example of the bus system in 1st Embodiment. It is a figure which shows the format of the data communicated between the bus adapters in 1st Embodiment. It is a figure which shows the structural example of the bus adapters 102, 104, and 107 in 1st Embodiment. It is a figure which shows the example which allocated the identification number to each bus adapter 402-407. It is a figure which shows the example which allocated another identification number different from FIG. It is a block diagram which shows the structural example of the bus system in 2nd Embodiment. It is a flowchart which shows the process which determines the threshold value of the route selection in 2nd Embodiment. It is a figure which shows the bus adapter which allocated the threshold value of the route selection in 2nd Embodiment. It is a figure for demonstrating determination of the path | route in 2nd Embodiment. It is a figure for demonstrating determination of the path | route in a modification.

Explanation of symbols

100 Bus System 101 Ring Bus 102 Bus Adapter 103 Bus Adapter 104 Bus Adapter 105 Bus Adapter 106 Bus Adapter 107 Bus Adapter 108a Function Block 108b Function Block 108c Function Block 108d Function Block 108e Function Block 108f Function Block 109 Bypass Path 200 Packet 201 Receiver Identification number field 202 Header part 203 Body part

Claims (7)

A ring bus to which a plurality of bus adapters are connected, and at least one bypass path outside the ring bus that connects two of the plurality of bus adapters directly or via one or more other bus adapters. In the bus system that has
Route determination means for determining a route at a branch point between the ring bus and the bypass route based on identification information for identifying the plurality of bus adapters and reception side identification information for identifying a bus adapter on the reception side;
A bus system comprising: a communication unit configured to perform communication between an arbitrary transmission-side bus adapter and a reception-side bus adapter on a route determined by the route determination unit.   The bus system according to claim 1, wherein the ring bus and the bypass path transmit data in one direction.   3. The bus system according to claim 1, wherein the route at the branch point is determined by comparing the receiving side identification information with a predetermined threshold value.   3. The bus system according to claim 1, wherein the route at the branch point is determined by a specific bit group indicating the receiving side identification information. A ring bus to which a plurality of bus adapters are connected, and at least one bypass path outside the ring bus that connects two of the plurality of bus adapters directly or via one or more other bus adapters. A bus system route determination method comprising:
A path determination step of determining a path at a branch point between the ring bus and the bypass path based on identification information for identifying the plurality of bus adapters and reception side identification information for identifying a bus adapter on the reception side;
A bus system route determination method comprising: a communication step of performing communication between an arbitrary transmission-side bus adapter and a reception-side bus adapter on the route determined in the route determination step.   A program for causing a computer to execute the bus system route determination method according to claim 5.   A computer-readable recording medium on which the program according to claim 6 is recorded.

Images