JP2007213411A - Bus bridge device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a plurality of host devices to share one or more storage devices. <P>SOLUTION: This bus bridge device comprises host-side bus interfaces 10a-10d, host-side register groups 11a-11d, storage-side bus interfaces 12a and 12b, storage-side register groups 13a and 13b, a switch part 14 and a control part 15. The switch part 14 switches, in response to control by the control part 15, connection of a plurality of data paths between the host-side bus interfaces 10a-10d and the storage-side bus interfaces 12a and 12b. The control part 15 controls the switch part 14 based on commands stored in the host-side register groups 11a-11d, and the commands is transferred between the host-side register groups 11a-11d and the storage-side register groups 13a and 13b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a bus bridge device, and particularly to a bus bridge device that connects a plurality of host devices and one or more storage devices.

  At present, with the spread of portable personal computers (hereinafter also referred to as “PCs”), there is an environment in which data editing operations and the like by PCs can be performed in various places. By constructing a LAN (Local Area Network) and connecting storage devices and PCs that operate with various protocols to the network, control devices with server functions and storage devices connected to the PC can be connected to other PCs on the network. Can also be used. Normally, when a LAN is constructed, device management using an IP network is performed.

On the other hand, a protocol conversion unit for performing data transmission / reception between a PC (host device) and a storage device operating with a protocol such as ATAPI or SCSI via a serial bus such as IEEE1394 or USB without using an IP network. (For example, refer to Patent Documents 1 and 2).
JP 2003-303164 A JP 2005-92353 A

  By constructing a LAN, one or more PCs and a plurality of storage devices can be connected to each other. However, in constructing a LAN, it is necessary to prepare facilities such as a server for IP management, a network contact point, and a router and a hub as connection nodes, which increases costs. In addition, prior settings for connecting to the IP network are required on both the server side and the PC (client) side.

  On the other hand, the configuration based on the bus bridge has an advantage that it can be realized at a lower cost than the LAN. However, since it is assumed that there is one host device, a plurality of host devices cannot share one or more storage devices.

  In view of the above problems, an object of the present invention is to share one or more storage devices among a plurality of host devices with a simple configuration using a bus bridge.

  Means taken by the present invention in order to solve the above-mentioned problems are as a bus bridge device, a plurality of host-side bus interfaces connected to the plurality of host devices in a one-to-one correspondence, and the plurality of host-side bus interfaces. A one-to-one correspondence is provided, and a plurality of host-side register groups that temporarily store commands transmitted from the plurality of host devices are connected to the one or more storage devices in a one-to-one correspondence. One or more storage-side bus interfaces and one one-to-one correspondence with the one or more storage-side bus interfaces and temporarily storing commands transmitted to each of the one or more storage devices The storage side register group, the plurality of host side bus interfaces, and the one or more storage side bus interfaces. A plurality of data paths between the switch unit for switching presence / absence of electrical connection, the switch unit based on a command stored in the plurality of host side register groups, and the plurality of host side registers It is assumed that a control unit is provided that exchanges commands between the group and the one or more storage-side register groups.

  According to this, there are a plurality of host-side bus interfaces connected in a one-to-one correspondence with a plurality of host devices, and one or more storage-side bus interfaces connected in a one-to-one correspondence with one or more storage devices. The presence or absence of electrical connection for a plurality of data paths between them is switched by the switch unit in accordance with an instruction from the control unit based on a command issued from the host device. Therefore, the storage apparatus can be shared by a plurality of host apparatuses without using an IP network.

  Preferably, a connection information storage unit that stores connection permission information regarding the plurality of data paths is provided. Here, the control unit controls the switch unit in consideration of the connection possibility information.

  According to this, it is possible to impose restrictions on the connection of data paths between a plurality of host apparatuses and storage apparatuses, and it is possible to perform more suitable data path connection control.

  More preferably, the connectability information is rewritable. As a result, it is possible to dynamically cope with changes in connection environment, changes in connection conditions, and the like.

  Preferably, a plurality of storage-side bus interfaces and a plurality of storage devices are provided. Here, it is assumed that the switch unit can simultaneously connect two or more of the plurality of data paths.

  According to this, among the plurality of data paths between the plurality of host devices and the plurality of storage devices, those that do not cause access contention can communicate simultaneously in parallel.

  Preferably, when the access requests from the plurality of host devices compete, the control unit arbitrates the access requests.

  According to this, for example, when data write requests from a plurality of host devices to one storage device overlap, data collision can be avoided.

  Specifically, when the control unit detects that the host device is in a connected state, the control unit determines which of the plurality of data paths conflicts with the data path related to the host device. It is instructed to disconnect and connect the data path related to the host device.

  According to this, for example, when a host device with a higher priority is newly connected, the storage device can be used in preference to other host devices.

  More specifically, when the control unit detects that an already connected host device is in a disconnected state, a data path related to the host device among the plurality of data routes to the switch unit. Shall be instructed to disconnect.

  According to this, it is possible to prevent the storage apparatus from being occupied by the host apparatus that is in a disconnected state.

  As described above, according to the present invention, one or more storage devices can be shared by a plurality of host devices with a simple configuration using a bus bridge without using an IP network.

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

  FIG. 1 is a block diagram showing a bus bridge device according to the present invention. The bus bridge device 1 includes interfaces 10a, 10b, 10c and 10d connected to host devices 2a, 2b, 2c and 2d, and register groups 11a and 11b which are provided in a one-to-one correspondence with these interfaces 10a to 10d. , 11c and 11d, interfaces 12a and 12b connected to the storage devices 3a and 3b, register groups 13a and 13b provided in a one-to-one correspondence with these interfaces 12a and 12b, a switch unit 14, and a control unit 15 and a connection information storage unit 16. The host devices 2a to 2d are, for example, a PC, a DVC (Digital Video Camera), a DSC (Digital Still Camera), or the like. The storage devices 3a and 3b are, for example, a hard disk device, DVD-ROM / RAM, CD-ROM / R / RW, MO, FD, memory IC, tape device, and the like. Note that the types and numbers of the host device and the storage device are examples, and the present invention is not limited to the above contents.

  The switch unit 14 has data paths related to all combinations between the interfaces 10a to 10d and the interfaces 12a and 12b (in this example, 4 × 2 = 8 types), and the plurality of data Switch the presence or absence of electrical connection for the route. This switching is controlled by the control unit 15 described later. The switch unit 14 can simultaneously connect a plurality of data paths. Data transmission / reception between the host apparatuses 2a to 2d and the storage apparatuses 3a and 3b is performed through the connected data paths.

  The interfaces 10a to 10d extract commands and data from the signals transmitted from the host devices 2a to 2d according to the respective protocols. Then, the extracted command is transmitted to the register groups 11a to 11d corresponding to the host devices 2a to 2d. The register groups 11a to 11d temporarily store the transmitted command. The interfaces 10a to 10d transmit and receive data to and from the interfaces 12a and 12b via the switch unit 14, and also transmit and receive data to and from the host devices 2a to 2d. The interfaces 10a to 10d are, for example, USB, IEEE 1394, Bluetooth (registered trademark), IrDA, or the like. Further, the interfaces 10a to 10d may be the same type or different types.

  The interfaces 12a and 12b transmit the commands stored in the register groups 13a and 13b to the storage apparatuses 3a and 3b according to the respective protocols. The interfaces 12a and 12b transmit and receive data to and from the interfaces 10a to 10d via the switch unit 14, and also transmit and receive data to and from the storage apparatuses 3a and 3b. The interfaces 12a and 12b are, for example, IDE, ATAPI, SCSI, SerialATA, SerialSCSI, or the like. The interfaces 12a and 12b may be the same type or different types.

  Based on the access requests from the host devices 2a to 2d, the control unit 15 determines the access availability based on the connection availability information stored in the connection information storage unit 16, which will be described later, and controls the switching of the data path in the switch unit 14. To do. For example, when a data write request from the host device 2a to the storage device 3a is issued, the control unit 15 determines that the access is possible based on the connection availability information stored in the connection information storage unit 16, and the interface 10a and the interface 13a The switch unit 14 is instructed to connect the data path therebetween. On the other hand, if the control unit 15 determines that access is not possible, the control unit 15 does not instruct the switch unit 14 to connect the data path. That is, the data path is not connected. Further, the control unit 15 exchanges commands issued from the host apparatuses 2a to 2d to the storage apparatuses 3a and 3b between the register groups 11a to 11d and the register groups 13a and 13b. That is, commands issued from the host devices 2a to 2d are transmitted to the storage devices 3a and 3b via the control unit 15.

  Further, when the access requests issued from the host devices 2a to 2d compete, the control unit 15 arbitrates the conflicting access requests. For example, when a data write request from the host apparatus 2a to a partial storage area 301 of the storage apparatus 3a and a data write request from the host apparatus 2b to a partial storage area 302 of the storage apparatus 3a conflict, The switch arbitrates the request and controls the switch unit 14 to connect one of the data paths between the interface 10a and the interface 13a and between the interface 10b and the interface 13a. This arbitration may be performed sequentially in the order in which the requests are generated, or may be performed according to the priority of the requests. Note that the data path switching control and the conflicting access request arbitration in the control unit 15 may be performed by software control using a CPU or a hardware sequencer. When performing by software control, the program may be rewritable.

  The connection information storage unit 16 stores connection availability information indicating whether or not each of the host devices 2a to 2d and the storage devices 3a and 3b can be connected. Based on this connection permission information, it is determined whether or not an access request issued from each of the host devices 2a to 2d is permitted. This connectability information may store information such as the device number and accessible area of the storage device that can be accessed from each of the host devices 2a to 2d. An area or the like may be stored. Note that the connection availability information may be rewritable from the outside.

  Hereinafter, the operation of the bus bridge device 1 will be specifically described.

  When the bus bridge device 1 and the storage devices 3a and 3b connected thereto are activated, the types and effective storage areas of the storage devices 3a and 3b are acquired by the control unit 15 via the interfaces 12a and 12b. On the other hand, the connected host devices 2a to 2d are detected by detecting the insertion / extraction of the cable at each interface 10a to 10d or detecting the power ON / OFF of the host device (for example, bus power monitoring in USB). Be notified.

  Here, for convenience of explanation, it is assumed that the host apparatus 2a can access only the storage area 301 of the storage apparatus 3a, and the host apparatus 2b can access only the storage area 302 of the storage apparatus 3a. Further, both the host devices 2c and 2d can access only the entire area of the storage device 3b.

  When the host device 2a issues a data read request from the storage area 301 of the storage device 3a, data and commands are extracted by the interface 10a, and the extracted commands are stored in the register group 11a. The command stored in the register group 11a is determined to be accessible by the control unit 15 from the information stored in the connection information storage unit 16, and is transmitted to the storage area 301 via the register group 13a and the interface 12a. . The switch unit 14 connects the data path between the interface 10a and the interface 12a, and the data read from the storage area 301 is transmitted to the host device 2a through the data path.

  On the other hand, when a request for reading data from the storage area 302 is issued by the host device 2a, the request is rejected by the control unit 15 and is notified to the host device 2a as an instruction issue error, for example. In the switch unit 14, the data path between the interface 10a and the interface 12a is not connected.

  When an access request is also issued from the host device 2c to the storage device 3b following the access request from the host device 2c to the storage device 3b, the access requests from the host devices 2c and 2d compete with each other. Access request arbitration is performed. Assuming that access request arbitration is performed sequentially in the order in which they are issued, during execution of an access request issued from the host device 2c, a signal indicating a request execution waiting is transmitted from the control unit 15 to the interface 10d. . The transmitted signal is transmitted to the host device 2d by the interface 10d by a method such as returning a Busy signal indicating a delay in issuing an instruction or not returning a Ready signal. When the execution of the access request from the host device 2c is completed, the transmission of the signal indicating the request execution waiting from the control unit 15 is stopped and the access request issued from the host device 2d is executed.

  The data path between the host apparatus 2a and the storage apparatus 3a and the data path between the host apparatus 2c or 2d and the storage apparatus 3b, which do not conflict with each other in the data path connection relationship, are simultaneously connected.

  As described above, according to this embodiment, one or a plurality of storage devices can be shared by a plurality of host devices without using an IP network. In addition, since data paths that do not compete with each other can be connected at the same time, a plurality of host devices can communicate with a plurality of storage devices at the same time.

  The control unit 15 monitors the connection status of the host device and the storage device, and when detecting that the host device has newly entered the connection status, for example, according to the priority of the device, The data path related to the device may be instructed to be connected with priority over others. In addition, when it is detected that the host device and the storage device that are already connected to the bus bridge device 1 are not connected, the disconnection of the data path related to the host device and the storage device may be instructed. Good.

  The data path may be connected when the host devices 2a to 2d are connected to the bus bridge device 1.

  Further, the connection information storage unit 16 may be omitted, and the control unit 15 may not have an arbitration function.

  In the bus bridge device according to the present invention, the connection of the data path is controlled by the control unit, and arbitration is performed when the access request conflicts. Therefore, in particular, one or a plurality of storage devices are arranged in a plurality of host devices. This is useful as a sharing method.

1 is a block diagram showing a bus bridge device according to the present invention.

Explanation of symbols

1 Bus bridge device 10a-10d interface (host side bus interface)
11a to 11d register group (host side register group)
12a, 12b interface (storage side bus interface)
13a, 13b register group (storage side register group)
14 Switch unit 15 Control unit 16 Connection information storage unit

Claims (7)

A plurality of host-side bus interfaces connected in a one-to-one correspondence with a plurality of host devices;
A plurality of host-side register groups provided in a one-to-one correspondence with the plurality of host-side bus interfaces, and temporarily storing commands transmitted from the plurality of host devices;
One or more storage-side bus interfaces connected in a one-to-one correspondence with one or more storage devices;
One or more storage-side register groups provided in a one-to-one correspondence with the one or more storage-side bus interfaces, and temporarily storing commands transmitted to the one or more storage devices;
A switch unit for switching presence / absence of electrical connection for a plurality of data paths between the plurality of host-side bus interfaces and the one or more storage-side bus interfaces;
Control for controlling the switch unit based on commands stored in the plurality of host-side register groups, and control for transferring commands between the plurality of host-side register groups and the one or more storage-side register groups And a bus bridge device. The bus bridge device according to claim 1, wherein
A connection information storage unit for storing connection availability information regarding the plurality of data paths;
The said control part controls the said switch part in consideration of the said connection possibility information, The bus bridge apparatus characterized by the above-mentioned. The bus bridge device according to claim 2,
The bus bridge device according to claim 1, wherein the connectability information is rewritable. The bus bridge device according to claim 1, wherein
A plurality of the storage-side bus interface and the storage device, respectively,
The bus bridge device, wherein the switch unit can simultaneously connect two or more of the plurality of data paths. The bus bridge device according to claim 1, wherein
When the access requests from the plurality of host devices compete with each other, the control unit arbitrates the access requests. The bus bridge device according to claim 1, wherein
When the control unit detects that an unconnected host device is in a connected state, the control unit disconnects one of the plurality of data paths that competes with the data path related to the host device from the plurality of data paths. And a bus bridge device that instructs to connect a data path related to the host device. The bus bridge device according to claim 1, wherein
When the control unit detects that an already-connected host device is in a disconnected state, the control unit instructs the switch unit to disconnect a data path related to the host device from the plurality of data paths. A bus bridge device characterized by being a thing.

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