JP4095384B2 - Information processing system, information processing apparatus, information processing method, program, and storage medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an information processing system, an information processing apparatus, an information processing method, a program, and a storage medium connected by an interface such as IEEE1394.
[0002]
[Prior art]
When performing one-to-one connection and communication between the host and the device in various interfaces such as Centronics, USB, and IEEE1394, a plurality of communication sessions are performed during one session of the communication protocol in order to control various functions of the device between the host and the device. Establish logical channel connection and transfer data for each channel.
[0003]
SBP (Serial Bus Protocol) -2, which is a data communication protocol on IEEE1394, itself has one data buffer for one ORB (Operation Request Block) which is a unit of data transfer in one logical unit. Since it is referred to, it has a mechanism for performing one-way single data channel and one-way half-duplex data communication, and it has been difficult to realize a plurality of logical channels. In SBP-3, which is a function expansion version of SBP-2 that is currently being developed, this point is noted, and two data buffers can be referred to the ORB that is a unit of data transfer in the logical unit. An extension was made to allow two data transfer channels per logical unit.
[0004]
[Problems to be solved by the invention]
However, in the SBP-3 data transfer, the flow control of the two data transfer channels is performed in units of ORBs. Therefore, when data transmission / reception cannot be performed in any one of the data transfer channels for some reason, either one of the data When the data transfer of the transfer channel is slower than the other channels, the channel that is normally transferred and the faster channel are affected.
[0005]
This is because even if the access to one data buffer is normally completed, if the access to the other data buffer is not completed, the completion notification for the ORB cannot be notified to the initiator of SBP-3, and the data transfer as a logical unit is performed. This is because of the delay.
[0006]
The present invention has been made to solve the above-described problems of the prior art, and an object thereof is to perform efficient data transfer using two channels such as an IEEE 1394 bus.
[0007]
[Means for Solving the Problems]
  In order to achieve the above object, a system according to the present invention provides:
  An information processing system including first and second devices connected by a communication control bus,
  The first device is:
Allocate multiple data buffers for one command block
  The second device is
  Data communication means for performing data communication with respect to at least one of the plurality of data buffers according to the command block;
  When data communication to any one of the plurality of data buffers is completed by the data communication meansData communication completed1 data bufferAnd status information including information for specifying a data buffer in which data communication is not completed among the plurality of data buffersTo the first device, and when the data communication to all the plurality of data buffers is completed by the data communication means, the data communication to all the data buffers is completed.Show statusCompletion notification means for notifying the first deviceWhen,
  It is characterized by having.
[0009]
The communication control bus conforms to IEEE 1394, and data communication is performed between the first device and the second device using the serial bus protocol 3 as a communication protocol.
[0010]
The completion notifying unit issues a status indicating a data buffer in which data communication has been completed, among the data buffers, to a status FIFO of the first device.
[0011]
The completion notification unit notifies completion of data communication independently for each data buffer.
[0012]
The completion notification means further notifies completion of data communication for all of the plurality of data buffers.
[0013]
The first device includes identification information of data stored in the data buffer in the ORB.
[0014]
  In order to achieve the above object, the method according to the present invention comprises:
  A communication method between first and second devices connected by a communication control bus, wherein a plurality of data buffers are allocated to one command block transmitted from the first device to the second device, and the second device Performs data communication with respect to at least one of the plurality of data buffers according to the command block, and when data communication with respect to any one of the plurality of data buffers is completed by the data communication,Data communication completed1 data bufferAnd status information including information for specifying a data buffer in which data communication is not completed among the plurality of data buffersTo the first device, and when the data communication to all the plurality of data buffers is completed by the data communication, the fact that the data communication to all the data buffers is completed.Show statusThe first device is notified.
[0016]
  In order to achieve the above object, an apparatus according to the present invention provides:
  An information processing apparatus connected to another device via a communication control bus,
  Data communication means for performing data communication with respect to at least one of the plurality of data buffers in accordance with the command block to another device in which a plurality of data buffers are allocated to one command block;
  When data communication to any one of the plurality of data buffers is completed by the data communication meansData communication completed1 data bufferAnd status information including information for specifying a data buffer in which data communication is not completed among the plurality of data buffersTo the first device, and when the data communication to all the plurality of data buffers is completed by the data communication means, the data communication to all the data buffers is completed.Show statusA completion notifying means for notifying the other device;
  It is characterized by having.
[0022]
Moreover, in order to achieve the said objective, the program concerning this invention makes a computer implement | achieve the said communication method. The storage medium according to the present invention stores the program.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the relative arrangement of components, the display screen, and the like described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified.
[0024]
(First embodiment)
Before describing the information processing system according to the first embodiment of the present invention, an outline of IEEE 1394 technology will be described.
[0025]
<Overview of IEEE 1394 technology>
Hereinafter, the technology of the IEEE 1394-1995 standard applied to the digital interface of the present embodiment will be briefly described. Details of the IEEE 1394-1995 standard (hereinafter referred to as the IEEE 1394 standard) are described in “IEEE Standard for a High Performance Serial” published by IEEE (The Institute of Electrical and Electronics Engineers, Inc.) on August 30, 1996. Bus ”.
[0026]
(1) Overview
FIG. 2 shows an example of a communication system (hereinafter referred to as a 1394 network) composed of nodes having a digital interface (hereinafter referred to as a 1394 interface) compliant with the IEEE 1394 standard. The 1394 network constitutes a bus network that can communicate serial data.
[0027]
In FIG. 2, each of the nodes A to F is connected via a communication cable conforming to the IEEE 1394 standard. These nodes A to H are electronic devices such as a PC (Personal Computer), a digital VTR (Video Tape Recorder), a DVD (Digital Video Disc) player, a digital camera, a hard disk, and a monitor.
[0028]
The connection method of the 1394 network corresponds to the daisy chain method and the node branching method, and connection with a high degree of freedom is possible.
[0029]
Further, in the 1394 network, for example, when an existing device is deleted, a new device is added, or an existing device is turned on / off, the bus is automatically reset. By performing this bus reset, the 1394 network can automatically recognize a new connection configuration and assign ID information to each device. With this function, the 1394 network can always recognize the connection configuration of the network.
[0030]
The 1394 network has a function of relaying data transferred from other devices. With this function, all devices can grasp the operating status of the bus.
[0031]
The 1394 network has a function called Plug & Play. With this function, it is possible to automatically recognize connected devices by simply connecting them without turning off the power of all devices.
[0032]
The 1394 network supports data transfer rates of 100/200/400 Mbps. A device having a higher data transfer rate can support a lower data transfer rate, and thus devices corresponding to different data transfer rates can be connected to each other.
[0033]
Furthermore, the 1394 network supports two different data transfer methods (ie, an asynchronous transfer mode and an isochronous transfer mode).
[0034]
The asynchronous transfer mode is effective when transferring data that is required to be transferred asynchronously as needed (that is, control signals, file data, etc.). In addition, the isochronous transfer mode is effective when transferring data (that is, video data, audio data, etc.) required to continuously transfer a predetermined amount of data at a constant data rate.
[0035]
Asynchronous transfer mode and isochronous transfer mode can be mixed in each communication cycle (usually one cycle is 125 μS). Each transfer mode is executed after transfer of a cycle start packet (hereinafter referred to as CSP) indicating the start of a cycle.
[0036]
In each communication cycle period, the isochronous transfer mode is set to have a higher priority than the asynchronous transfer mode. In addition, the transfer bandwidth in the isochronous transfer mode is guaranteed within each communication cycle.
[0037]
(2) Architecture
Next, components of the 1394 interface will be described with reference to FIG.
[0038]
The 1394 interface is functionally composed of a plurality of layers (hierarchies). In FIG. 3, the 1394 interface is connected to the 1394 interface of another node via a communication cable 301 compliant with the IEEE 1394 standard. The 1394 interface has one or more communication ports 302, and the communication ports 302 are connected to a physical layer 303 included in the hardware unit.
[0039]
In FIG. 3, the hardware unit is composed of a physical layer 303 and a link layer 304. The physical layer 303 performs physical and electrical interfaces with other nodes, bus reset detection and processing accompanying it, encoding / decoding of input / output signals, arbitration of bus use rights, and the like. The link layer 304 performs communication packet generation, transmission / reception, cycle timer control, and the like.
[0040]
In FIG. 3, the firmware section includes a transaction layer 305 and a serial bus management 306. The transaction layer 305 manages the asynchronous transfer mode and provides various transactions (read, write, lock). The serial bus management 306 provides functions for controlling the own node, managing the connection state of the own node, managing ID information of the own node, and managing resources of the serial bus network based on the CSR architecture described later.
[0041]
As described above, the hardware unit and the firmware unit substantially constitute a 1394 interface, and their basic configuration is defined by the IEEE 1394 standard.
[0042]
Further, the application layer 307 included in the software unit varies depending on the application software to be used, and controls how data is communicated on the network. For example, in the case of moving image data of a digital VTR, it is defined by a communication protocol such as AV / C protocol.
[0043]
(2-1) Link layer 304
FIG. 4 is a diagram showing services that the link layer 304 can provide. In FIG. 4, the link layer 304 provides the following four services. That is, (1) a link request (LK_DATA.request) for requesting transfer of a predetermined packet to the response node, (2) link notification (LK_DATA.indication) for notifying the response node of reception of the predetermined packet, (3) A link response (LK_DATA.response) indicating that an acknowledge from the response node has been received, and (4) a link confirmation (LK_DATA.confirmation) for confirming the acknowledge from the request node. The link response (LK_DATA.response) does not exist in the case of broadcast communication or isochronous packet transfer.
[0044]
The link layer 304 realizes the above-described two types of transfer methods, that is, the asynchronous transfer mode and the isochronous transfer mode, based on the above-described service.
[0045]
(2-2) Transaction layer 305
FIG. 5 is a diagram showing services that the transaction layer 305 can provide. In FIG. 5, the transaction layer 305 provides the following four services. Namely, (1) transaction request (TR_DATA.request) for requesting a predetermined transaction to the response node, (2) transaction notification (TR_DATA.indication) for notifying the response node of reception of the predetermined transaction request, (3) Transaction response (TR_DATA.response) indicating that the status information from the response node (including data in the case of write and lock) has been received, and (4) transaction confirmation for confirming status information from the request node (TR_DATA.confirmation ).
[0046]
The transaction layer 305 manages asynchronous transfers based on the above-described services, and includes the following three types of transactions: (1) read transaction, (2) write transaction, and (3) lock transaction. Realize.
[0047]
(1) In the read transaction, the request node reads information stored at a specific address of the response node.
[0048]
(2) In the write transaction, the requesting node writes predetermined information to a specific address of the responding node.
[0049]
(3) In the lock transaction, the request node transfers reference data and update data to the response node, compares the specific address information of the response node with the reference data, and determines the specific address according to the comparison result. Update the information to update data.
[0050]
(2-3) Serial bus management 306
Specifically, the serial bus management 306 can provide the following three functions. The three functions are (1) node control, (2) isochronous resource manager (hereinafter IRM), and (3) bus manager.
[0051]
{Circle around (1)} Node control provides a function of managing the above-described layers and managing asynchronous transfer executed with other nodes.
[0052]
(2) The IRM provides a function for managing isochronous transfer executed with other nodes. Specifically, information necessary for assigning the transfer bandwidth and channel number is managed, and the information is provided to other nodes.
[0053]
The IRM exists only on the local bus, and is dynamically selected from other candidates (nodes having an IRM function) at each bus reset. In addition, the IRM may provide a part of functions (connection configuration management, power management, speed information management, etc.) that can be provided by a bus manager described later.
[0054]
(3) The bus manager has an IRM function and provides a more advanced bus management function than the IRM. Specifically, more advanced power management (information such as whether power can be supplied via a communication cable or whether power supply is required is managed for each node), more advanced speed information Management (management of maximum transfer speed between each node), management of more advanced connection configuration (creation of topology map), bus optimization based on these management information, etc., and further, this information is transmitted to other nodes It has a function to provide.
[0055]
The bus manager can provide a service for controlling the serial bus network to the application. The service includes a serial bus control request (SB_CONTROL.request), a serial bus event control confirmation (SB_CONTROL.confirmation), a serial bus event notification (SB_CONTROL.indication), and the like.
[0056]
SB_CONTROL.request is a service for which an application requests a bus reset. SB_CONTROL.confirmation is a service for confirming SB_CONTROL.request to the application. SB_CONTROL.indication is a service that notifies an application of an event that occurs asynchronously.
[0057]
(3) Address specification
FIG. 6 is a diagram for explaining an address space in the 1394 interface. The 1394 interface defines a 64-bit width address space according to a CSR (Command and Status Register) architecture conforming to ISO / IEC 13213: 1994.
[0058]
In FIG. 6, the first 10-bit field 601 is used for an ID number for designating a predetermined bus, and the next 6-bit field 602 is used for an ID number for designating a predetermined device (node). The upper 16 bits are called “node ID”, and each node identifies another node by this node ID. Each node can perform communication by identifying the other party using this node ID.
[0059]
The remaining 48 bits field specifies the address space (256 Mbyte structure) of each node. Among them, a 20-bit field 603 designates a plurality of areas constituting the address space.
[0060]
In the field 603, the part “0-0xFFFFD” is called a memory space. The portion “0xFFFFE” is called a private space and is an address that can be freely used in each node. The part “0xFFFFE” is called a register space, and stores information common to nodes connected to the bus. Each node can manage communication between the nodes by using information in the register space.
[0061]
The last 28-bit field 604 designates an address where information that is common or unique in each node is stored.
[0062]
For example, in the register space, the first 512 bytes are used for CSR architecture core (CSR core) registers. FIG. 7 shows the address and function of information stored in the CSR core register. The offset in the figure is a relative position from “0xFFFFF0000000”.
[0063]
The next 512 bytes are used as a serial bus register. FIG. 8 shows the address and function of information stored in the serial bus register. The offset in the figure is a relative position from “0xFFFFF0000200”.
[0064]
The next 1024 bytes are used for a configuration ROM.
[0065]
The configuration ROM has a minimum format and a general format, and is arranged from “0xFFFFF0000400”. A minimum configuration ROM is shown in FIG. In FIG. 9, the vendor ID is a 24-bit numerical value uniquely assigned to each vendor by IEEE.
[0066]
A general configuration ROM is shown in FIG. In FIG. 10, the vendor ID is stored in a root directory 1002. The Bus Info Block 1001 and the Root Leaf 1005 can hold a node unique ID as unique ID information for identifying each node.
[0067]
Here, the node unique ID is a unique ID that can identify one node regardless of the manufacturer and model. The node unique ID is composed of 64 bits, the upper 24 bits indicate the above-mentioned vendor ID, and the lower 48 bits indicate information that can be freely set by a manufacturer that manufactures each node (for example, the manufacturing number of the node). This node unique ID is used when, for example, a specific node is continuously recognized before and after a bus reset.
[0068]
In FIG. 10, a root directory 1002 can hold information regarding basic functions of the node. Detailed function information is stored in a unit directory 1004 as a subdirectory offset from the root directory 1002. In the unit directory 1004, for example, information on software units supported by the node is stored. Specifically, information regarding a data transfer protocol for performing data communication between nodes, a command set defining a predetermined communication procedure, and the like is held.
[0069]
In FIG. 10, a node dependent information directory (Node Dependent Info Directory) 1003 can hold device-specific information. The node dependent information directory 1003 is offset by the root directory 1002.
[0070]
Further, in FIG. 10, vendor-specific information (Vendor Dependent Information) 1006 can hold information unique to a vendor that manufactures or sells a node.
[0071]
The remaining area is called a unit space, and specifies an address in which information unique to each node, for example, identification information (company name, model name, etc.) of each device and usage conditions are stored. FIG. 11 shows addresses and functions of information stored in the serial bus device registers in the unit space. The offset in the figure is a relative position from “0xFFFFF0000800”.
[0072]
In general, each node should use only the first 2048 bytes of the register space if it is desired to simplify the design of a heterogeneous bus system. In other words, it is desirable that the CSR core register, serial bus register, configuration ROM, and the first 2048 bytes of the unit space are combined to be 4096 bytes.
[0073]
(4) Configuration of communication cable
FIG. 12 shows a cross-sectional view of a communication cable conforming to the IEEE 1394 standard.
[0074]
The communication cable includes two pairs of twisted pair signal lines and a power supply line. By providing the power supply line, the 1394 interface can supply power to a device whose main power is turned off, a device whose power is reduced due to a failure, or the like. Note that the voltage of the power source flowing in the power line is defined as 8 to 40 V, and the current is defined as the maximum current DC1.5A.
[0075]
An information signal encoded by the DS-Link (Data / Strobe Link) encoding method is transmitted to the two pairs of twisted pair signal lines. FIG. 13 is a diagram for explaining the DS-Link encoding method.
[0076]
This DS-Link encoding method is suitable for high-speed serial data communication, and its configuration requires two pairs of twisted pairs. One pair of twisted pairs is configured to send data signals, and the other twisted pair is configured to send strobe signals. The receiving side can reproduce the clock by taking the exclusive OR of the data signal received from the two sets of signal lines and the strobe signal.
[0077]
By using the DS-Link encoding method, the 1394 interface has the following advantages, for example. {Circle around (1)} Transfer efficiency is higher than other encoding methods. (2) No PLL circuit is required and the circuit scale of the controller LSI can be reduced. {Circle around (3)} Since there is no need to send information indicating the idle state, the transceiver circuit can be easily put into the sleep state, and power consumption can be reduced.
[0078]
(5) Bus reset
The 1394 interface of each node can automatically detect that a change has occurred in the network connection configuration. In this case, the 1394 network performs a process called bus reset according to the following procedure. A change in connection configuration can be detected by a change in bias voltage applied to a communication port included in each node.
[0079]
A node that detects a change in the connection configuration of the network (for example, increase / decrease in the number of nodes due to node insertion / removal, power ON / OFF of the node, etc.) A bus reset signal on the bus.
[0080]
The 1394 interface of the node that has received the bus reset signal transmits the occurrence of the bus reset to its link layer 304 and transfers the bus reset signal to the other nodes. The node that has received the bus reset signal clears the network connection configuration and the node ID assigned to each device that have been recognized so far. Finally, after all the nodes detect the bus reset signal, each node automatically performs an initialization process (that is, recognition of a new connection configuration and assignment of a new node ID) accompanying the bus reset.
[0081]
The bus reset can be started by the application layer 307 issuing a command directly to the physical layer 303 under the control of the host side, in addition to the start due to the change in the connection configuration as described above. Is possible.
[0082]
In addition, when the bus reset is activated, the data transfer is temporarily interrupted and resumed under a new network after the initialization process accompanying the bus reset is completed.
[0083]
(6) Sequence after starting bus reset
After the bus reset is activated, the 1394 interface of each node automatically recognizes a new connection configuration and assigns a new node ID. Hereinafter, a basic sequence from the start of the bus reset to the node ID assignment process will be described with reference to FIGS.
[0084]
FIG. 14 is a diagram illustrating a state after the bus reset is activated in the 1394 network of FIG.
[0085]
In FIG. 14, node A has one communication port, node B has two communication ports, node C has two communication ports, node D has three communication ports, node E has one communication port, and node F has one communication. Port. The communication port of each node is assigned a port number for identifying each port.
[0086]
Hereinafter, the process from the start of the bus reset to the node ID assignment in FIG. 14 will be described with reference to the flowchart of FIG.
[0087]
In FIG. 15, each of the nodes A to F configuring the 1394 network constantly monitors whether or not a bus reset has occurred (step S1501). When a bus reset signal is output from a node that has detected a change in connection configuration, each node executes the following processing.
[0088]
After the occurrence of the bus reset, each node declares a parent-child relationship between the respective communication ports (step S1502).
[0089]
Each node repeats the process of step S1502 until the parent-child relationship between all nodes is determined (step S1503).
[0090]
After the parent-child relationship between all the nodes is determined, the 1394 network determines a node that performs network arbitration, that is, a route. (Step S1504).
[0091]
After determining the route, each 1394 interface of each node performs an operation of automatically setting its own node ID (step S1505).
[0092]
Each node executes the process of step S1505 based on a predetermined procedure until the node ID is set for all the nodes (step S1506).
[0093]
After node IDs are finally set for all nodes, each node performs isochronous transfer or asynchronous transfer (step S1507).
[0094]
While executing the processing of step S1507, the 1394 interface of each node again monitors the occurrence of a bus reset. If a bus reset has occurred, the processing from step S1501 is executed again.
[0095]
With the above procedure, the 1394 interface of each node can automatically execute recognition of a new connection configuration and assignment of a new node ID each time a bus reset is activated.
[0096]
(7) Determination of parent-child relationship
Next, the processing in step S1502 shown in FIG. 15 (that is, processing for recognizing the parent-child relationship between each node) shown in FIG. 15 will be described in detail with reference to FIG.
[0097]
In FIG. 16, after the occurrence of the bus reset, each of the nodes A to F on the 1394 network confirms the connection state (connected or not connected) of the communication port included in the node (step S1601).
[0098]
After confirming the connection state of the communication ports, each node counts the number of communication ports (hereinafter referred to as connection ports) connected to other nodes (step S1602).
[0099]
As a result of the processing in step S1602, if the number of connection ports is one, the node recognizes that it is a “leaf” (step S1603). Here, a leaf is a node connected to only one node.
[0100]
The node serving as the leaf declares that it is a “child” to the node connected to the connection port (step S1604). At this time, the leaf recognizes that the connection port is a “parent port (communication port connected to the parent node)”.
[0101]
Here, the declaration of the parent-child relationship is first performed between the leaf and the branch, which are the ends of the network, and then sequentially performed between the branch and the branch. The parent-child relationship between each node is determined in order from the communication port that can be declared early. In addition, between each node, the communication port declared to be a child is recognized as a “parent port”, and the communication port receiving the declaration is “child port (communication port connected to child node)”. It is recognized that there is. For example, in FIG. 14, the nodes A, E, and F declare a parent-child relationship after recognizing that they are leaves. As a result, the node A-B is determined as a child-parent, the node E-D is determined as a child-parent, and the node FD is determined as a child-parent.
[0102]
If the number of connection ports is two or more as a result of the processing in step S1602, the node recognizes itself as a “branch” (step S1605). Here, a branch is a node connected to two or more nodes.
[0103]
The node serving as the branch receives a parent-child relationship declaration from the node of each connection port (step S1606). The connection port that received the declaration is recognized as a “child port”.
[0104]
After recognizing one connection port as a “child port”, the branch detects whether or not there are two or more connection ports that have not yet been determined to have a parent-child relationship (that is, undefined ports) (step S1607). As a result, when there are two or more undefined ports, the branch performs the operation of step S1606 again.
[0105]
If only one undefined port exists as a result of step S1607, the branch recognizes that the undefined port is a “parent port”, and “is a child” for the node connected to the port. Is declared (steps S1608 and S1609).
[0106]
Here, the branch cannot declare to other nodes that it is a child until there is one remaining undefined port. For example, in FIG. 14, nodes B, C, and D recognize that they are branches and accept declarations from leaves or other branches. The node D declares the parent-child relationship to the node C after the parent-child relationship between DE and DF is determined. Further, the node C that has received the declaration from the node D declares a parent-child relationship to the node B.
[0107]
If there is no undefined port as a result of the processing in step S1608 (that is, if all connection ports included in the branch are parent ports), the branch recognizes that it is the root. . (Step S1610).
[0108]
For example, in FIG. 14, a node B in which all of the connection ports are parent ports is recognized by other nodes as a route for arbitrating communication on the 1394 network. Here, the node B is determined to be the root, but if the timing of declaring the parent-child relationship of the node B is earlier than the timing of declaring the node C, another node may become the root. In other words, depending on the timing of declaration, any node may become the root. Therefore, the same node is not necessarily the root even in the same network configuration.
[0109]
Thus, by declaring the parent-child relationship of all the connection ports, each node can recognize the connection configuration of the 1394 network as a hierarchical structure (tree structure) (step S1611). Note that the above parent node is higher in the hierarchical structure, and the child node is lower in the hierarchical structure.
[0110]
(8) Node ID assignment
FIG. 17 is a flowchart for explaining in detail the processing in step S1505 shown in FIG. 15 (that is, processing for automatically assigning the node ID of each node). Here, the node ID is composed of a bus number and a node number. In this embodiment, each node is connected to the same bus, and each node is assigned the same bus number. To do.
[0111]
In FIG. 17, the route gives the node ID setting permission to the communication port having the smallest number among the child ports connected to the node whose node ID is not set (step S1701).
[0112]
In FIG. 17, after setting the node IDs of all the nodes connected to the child port with the smallest number, the root sets the child port and sets the same control for the next smallest child port. Do. Finally, after the ID setting of all the nodes connected to the child port is completed, the node ID of the root itself is set. Note that the node numbers included in the node ID are basically assigned 0, 1, 2,... In the order of leaves and branches. Therefore, the route has the largest node number.
[0113]
In step S1701, the node that has obtained the setting permission determines whether or not there is a child port including a node whose node ID is not set among its child ports (step S1702).
[0114]
When a child port including an unset node is detected in step S1702, the node that has obtained the above setting permission performs control so as to give the setting permission to the node directly connected to the child port (step S1703). ).
[0115]
After the processing in step S1703, the node that has obtained the above setting permission determines whether there is a child port including a node whose node ID is not set among its child ports (step S1704). If the presence of a child port including an unset node is detected after the process of step S1704, the node executes the process of step S1703 again.
[0116]
If no child port including an unset node is detected in step S1702 or S1704, the node that has obtained the setting permission sets its own node ID (step S1705).
[0117]
The node that has set its own node ID broadcasts a self ID packet including information about its own node number, communication port connection status, and the like (step S1706). Note that broadcasting means transferring a communication packet of a certain node to an unspecified number of nodes constituting the 1394 network.
[0118]
Here, each node can recognize the note number assigned to each node by receiving this self-ID packet, and can know the node number assigned to itself. For example, in FIG. 14, the node Node B, which is the root, grants node ID setting permission to the node A connected to the communication port having the minimum port number “# 1”. Node A assigns its own node number “No. 0”, and sets a node ID composed of a bus number and a node number for itself. Node A broadcasts a self ID packet including the node number.
[0119]
FIG. 18 shows a configuration example of the self ID packet. In FIG. 18, 1801 is a field for storing the node number of the node that sent the self-ID packet, 1802 is a field for storing information on the transfer rate that can be supported, and 1803 is a bus management function (whether or not the bus manager is capable). A field indicating presence / absence, 1804 is a field for storing information on power consumption and supply characteristics.
[0120]
In FIG. 18, 1805 is a field for storing information on the connection state of the communication port having the port number “# 0” (connected, unconnected, parent-child relationship of communication ports, etc.), and 1806 is the port number “# 1”. A field for storing information related to the connection status of the communication port (connected, not connected, parent-child relationship of the communication port, etc.) 1807 is information related to the connection status of the communication port having the port number “# 2” (connected, not connected, communication) This is a field for storing a parent-child relationship of ports).
[0121]
If the node that transmits the self ID packet has the capability of becoming a bus manager, the contender bit shown in the field 1803 is set to “1”, and if there is no capability that can be set, the contender bit is set to 0.
[0122]
Here, the bus manager refers to bus power management (whether power can be supplied via a communication cable, whether power supply is required, based on various information included in the self-ID packet described above. Etc. for each node), speed information management (the maximum transfer speed between each node is managed from information on the transfer speed that can be handled by each node), topology map information management (for communication ports) It is a node having a function of managing a network connection configuration from parent-child relationship information), optimizing a bus based on topology map information, and providing such information to other nodes. With these functions, a node serving as a bus manager can perform bus management of the entire 1394 network.
[0123]
After the processing in step S1706, the node that has set the node ID determines whether there is a parent node (step S1707). If there is a parent node, the parent node executes the processing from step S1702 onward. Then, permission is given to a node for which a node ID has not yet been set.
[0124]
If no parent node exists, it is determined that the node is the root itself. The root determines whether or not node IDs are set for the nodes connected to all the child ports (step S1708).
[0125]
In step S1708, if the ID setting process for all nodes is not completed, the root gives ID setting permission to the child port having the smallest number among the child ports including the node (step S1701). Thereafter, the processing after step S1702 is executed.
[0126]
When the ID setting process for all nodes is completed, the root executes setting of its own node ID (step S1709). After setting the node ID, the route broadcasts a self ID packet (step S1710).
[0127]
Through the above processing, the 1394 network can automatically assign a node ID to each node.
[0128]
Here, after the node ID setting process, when a plurality of nodes have the bus manager capability, the node having the largest node number becomes the bus manager. That is, when the route having the largest node number in the network has a function that can be a bus manager, the route becomes the bus manager.
[0129]
However, if the route does not have the function, the node having the next highest node number in the route becomes the bus manager. Further, which node is the bus manager can be grasped by checking the contender bit 1803 in the self ID packet broadcast by each node.
[0130]
(9) Arbitration
FIG. 19 is a diagram for explaining arbitration in the 1394 network of FIG.
[0131]
In the 1394 network, arbitration of bus use right is always performed prior to data transfer. The 1394 network is a logical bus network, and the same communication packet can be transferred to all the nodes in the network by relaying the communication packet transferred from each node to other nodes. Therefore, arbitration is always required to prevent communication packet collisions. Thus, only one node can perform transfer at a certain time.
[0132]
FIG. 19A is a diagram illustrating a case where the node B and the node F issue a bus use right request.
[0133]
When arbitration starts, the nodes B and F issue a bus use right request to the parent node. The parent node (that is, node C) that has received the request from node B relays the right to use the bus toward its parent node (that is, node D). This request is finally delivered to the route (node D) that performs arbitration.
[0134]
The route that receives the bus use request determines which node uses the bus. This arbitration work can be performed only by the root node, and the bus use permission is given to the node that has won the arbitration.
[0135]
FIG. 19B is a diagram illustrating that the request from the node F is permitted and the request from the node B is rejected.
[0136]
The route sends a DP (Data prefix) packet to the node that lost the arbitration to inform that it has been rejected. The rejected node waits for a bus use request until the next arbitration.
[0137]
By controlling arbitration as described above, the 1394 network can manage the right to use the bus.
[0138]
(10) Communication cycle
The isochronous transfer mode and the asynchronous transfer mode can be mixed in a time division manner within each communication cycle period. Here, the period of the communication cycle is usually 125 μS.
[0139]
FIG. 20 is a diagram illustrating a case where the isochronous transfer mode and the asynchronous transfer mode are mixed in one communication cycle.
[0140]
The isochronous transfer mode is executed with priority over the asynchronous transfer mode. The reason is that after the cycle start packet, the idle period (subaction gap) required to start asynchronous transfer is set longer than the idle period (isochronous gap) required to start isochronous transfer. It is because it has been. As a result, isochronous transfer is executed in preference to asynchronous transfer.
[0141]
In FIG. 20, at the start of each communication cycle, a cycle start packet (hereinafter referred to as CSP) is transferred from a predetermined node. Each node can measure the same time as other nodes by adjusting the time using this CSP.
[0142]
(11) Isochronous transfer mode
The isochronous transfer mode is a synchronous transfer method. The isochronous mode transfer can be executed in a predetermined period after the start of the communication cycle. The isochronous transfer mode is always executed every cycle in order to maintain real-time transfer.
[0143]
The isochronous transfer mode is a transfer mode particularly suitable for transferring data that requires real-time transfer such as moving image data and audio data. The isochronous transfer mode is not a one-to-one communication like the asynchronous transfer mode but a broadcast communication. That is, a packet transmitted from a certain node is uniformly transferred to all nodes on the network. Note that ack (reception confirmation reply code) does not exist in isochronous transfer.
[0144]
In FIG. 20, channel e (ch e), channel s (ch s), and channel k (ch k) indicate periods during which each node performs isochronous transfer. In the 1394 interface, different channel numbers are assigned to distinguish a plurality of different isochronous transfers. As a result, isochronous transfer between a plurality of nodes becomes possible. Here, this channel number does not specify a transmission destination, but merely gives a logical number to data.
[0145]
The isochronous gap shown in FIG. 20 indicates the idle state of the bus. After this idle state has passed for a certain time, a node desiring isochronous transfer determines that the bus can be used and performs arbitration.
[0146]
Next, FIG. 21 shows a format of a communication packet transferred based on the isochronous transfer mode. Hereinafter, a communication packet transferred based on the isochronous transfer mode is referred to as an isochronous packet.
[0147]
In FIG. 21, an isochronous packet is composed of a header part 2101, a header CRC 2102, a data part 2103, and a data CRC 2104.
[0148]
The header part 2101 includes a field 2105 for storing the data length of the data part 2103, a field 2106 for storing format information of the isochronous packet, a field 2107 for storing the channel number of the isochronous packet, a packet format, and a process to be executed. There is a field 2108 for storing a transaction code (tcode) for identifying the ID and a field 2109 for storing a synchronization code.
[0149]
(12) Asynchronous transfer mode
Asynchronous transfer mode is an asynchronous transfer method. Asynchronous transfer can be executed after the end of the isochronous transfer period until the next communication cycle is started (that is, until the CSP of the next communication cycle is transferred).
[0150]
In FIG. 20, the first subaction gap indicates the idle state of the bus. After this idle time reaches a constant value, a node desiring asynchronous transfer determines that the bus can be used and performs arbitration.
[0151]
The node that has obtained the bus use right by arbitration transfers the packet shown in FIG. 22 to a predetermined node. The node receiving this packet returns ack (reception confirmation return code) or a response packet after ack gap.
[0152]
FIG. 22 is a diagram illustrating a format of a communication packet based on the asynchronous transfer mode. Hereinafter, a communication packet transferred based on the asynchronous transfer mode is referred to as an asynchronous packet.
[0153]
In FIG. 22, the asynchronous packet is composed of a header part 2201, a header CRC 2202, a data part 2203, and a data CRC 2204.
[0154]
In the header section 2201, a field 2205 indicates a node ID of a destination node, a field 2206 indicates a node ID of a source node, a field 2207 indicates a label indicating a series of transactions, and a field 2208 indicates a retransmission status. Code, field 2209 is the transaction code (tcode) identifying the format of the packet and the processing to be executed, field 2210 is the priority, field 2211 is the destination memory address, field 2212 is the data in the data part The extended field 2213 stores the extended transaction code.
[0155]
Asynchronous transfer is one-to-one communication from the self node to the partner node. The packet transferred from the transfer source node is distributed to each node in the network, but other than the address addressed to itself is ignored. Therefore, only the destination node can read the packet.
[0156]
If it is time to transfer the next CSP during asynchronous transfer, the next CSP is transmitted after the transfer is completed without forcibly interrupting the transfer. As a result, when one communication cycle continues for 125 μS or more, the next communication cycle period is shortened accordingly. By doing so, the 1394 network can maintain a substantially constant communication cycle.
[0157]
(13) Device map
In order to create a device map, there are the following means on the IEEE 1394 standard as a means for an application to know the topology of the 1394 network.
[0158]
1. Read the bus manager topology map register
2. Estimate from self ID packet at bus reset
However, with the above 1 and 2 methods, the topology of the cable connection order based on the parent-child relationship of each node is known, but the topology of the physical positional relationship cannot be known (the problem is that even ports that are not mounted can be seen) Also).
[0159]
In addition, there is a means for storing information for creating a device map as a database other than the configuration ROM. In this case, the means for obtaining various types of information depends on a protocol for database access.
[0160]
By the way, the configuration ROM itself and the function of reading the configuration ROM are necessarily provided by a device that complies with the IEEE 1394 standard. Therefore, by storing information such as device location and function in the configuration ROM of each node and giving them the ability to read them from the application, each node can be used without depending on a specific protocol such as database access or data transfer. Application can implement a so-called device map display function.
[0161]
That is, the configuration ROM can store the physical position, function, and the like as node-specific information, and can be used to realize a device map display function.
[0162]
In this case, as a means for the application to know the 1394 network topology based on the physical positional relationship, the method of knowing the topology of the 1394 network by reading the configuration ROM of each node at the time of bus reset or a request from the user. Is possible. Further, if not only the physical position of the node but also various node information such as functions are described in the configuration ROM, the function information of each node can be obtained simultaneously with the physical position of the node by reading the configuration ROM. be able to. When the application acquires the configuration ROM information of each node, an API that acquires arbitrary configuration ROM information of the designated node is used.
[0163]
By using such means, device applications on the IEEE 1394 network can create various device maps such as physical topology maps, function maps of each node, etc. It is also possible to select a device having a function.
[0164]
(14) Overview of SBP-2
SBP-2 (Serial Bus Protocol 2) is a protocol related to the IEEE 1394 bus, which has been discussed for standardization since 1996 as a project of the Technical Committee T10 under NCITS, and was standardized in 1998 as ANSI NCITS 325-1998. The layer is a command / data transfer protocol positioned above the transaction layer of IEEE 1394-1995. Initially, SBP-2 was developed with the primary purpose of operating devices on IEEE 1394 using SCSI commands, but other commands can be included in addition to SCSI commands.
[0165]
The following four can be cited as features of SBP-2.
[0166]
1) A master slave model having an initiator / target configuration, and the master initiator has all authority and responsibility such as login, logout, task, management, and command issue.
[0167]
2) A shared memory model that makes use of the features of IEEE 1394 as a bus model. The contents of requests to the target such as commands are basically all placed in the system memory, and the target receiving the request goes to read the contents of the system memory. Alternatively, information such as the requested status is written into the system memory.
[0168]
In other words, the resources for communication can be concentrated in one place, so the burden of resources can be greatly reduced, and the target can read and write to the system memory at its own pace. Speeding up is easy by making access H / W. In other words, it can be a high performance or a thorough low-cost model.
[0169]
3) Since there is a mechanism for describing a group of commands for exchanging messages as a series of linked lists, it is possible to conceal the degradation in efficiency due to latency, and high-speed and high-efficiency data communication utilizing the features of the IEEE 1394 bus can be realized.
[0170]
4) The structure does not depend on the command set. In other words, it can support various command sets.
[0171]
As shown in feature 1), since SBP-2 is a master slave model in which the initiator, which is the master, has all authority and responsibility, all operations are performed using the operation from the initiator as a trigger. A login, logout request, task management request, command, and the like from the initiator are sent to the target in a form included in a data structure called an ORB (Operation Request Block). Correctly, the initiator places it in its own memory and the target reads it. FIG. 23 shows main ORB types.
[0172]
1) Dummy ORB: Used to cancel a task when the target fetch agent is initialized. Treated as no operation by the target.
[0173]
2) Command block ORB: an ORB containing commands such as a data transfer command and a device control command. Details are shown in FIG. It has a data descriptor (data_descriptor) indicating the address and size of the corresponding data buffer or page table, and a data size field (data_size). Further, since it has a next ORB field (next_ORB) indicating the address of the next command block ORB, it is characterized in that commands can be linked.
[0174]
3) Management ORB: An ORB containing management requests (access requests including login and logout, and task management requests). Details are shown in FIG. It has a function field (function) that indicates the task management request contents (Abort Task Set, target reset, etc.) and a status FIFO (Status_FIFO) field that indicates the address of the completion status from the target. is there.
[0175]
Among these, regarding the management ORB, the initiator cannot issue the next ORB until the target returns a response. On the other hand, the command block ORB including the dummy ORB has a field for designating the address of the next ORB as the next ORB field as shown in FIG. 24. Therefore, the commands are linked one after another, and the form of the link list as shown in FIG. A series of command sequences can be issued with. When this next ORB field is null, it indicates that there is no subsequent ORB.
[0176]
The other fields of this command block ORB include fields (data descriptor and data size) indicating the address and size of the data buffer or page table. For example, if the command content is a write command, the target is indicated by the data descriptor. The data buffer on the designated system memory is accessed and the write data is read therefrom. If the content of the command is a read command, the target accesses the data buffer on the system memory indicated by the data descriptor and writes the data requested by the command there.
[0177]
27 and 28 show a case where the data buffer is shown directly and a case where it passes through the page table. The data buffer in the physically discontinuous area can be handled continuously by the page table, and there is no need to physically relocate the continuous logical area by virtual storage.
[0178]
A mechanism on the target side that executes various requests from the initiator is referred to as an agent. The agent includes a management agent that executes a management ORB and a command block agent that executes a command block ORB.
[0179]
The management agent has a management agent register that stores the address of the management ORB for the initiator to inform the target.
[0180]
The command block agent is also called a fetch agent because it fetches commands from the command link list of the initiator. The fetch agent also has a command block agent register including an ORB pointer register in which the initiator stores the head address of the command block ORB, a doorbell register for informing that the initiator wants to fetch a command to the target, and the like.
[0181]
When the target completes the execution of the ORB from the initiator, the target stores the execution completion status in an address indicated by the initiator status FIFO in the form of a data structure called a status block (regardless of whether the completion is successful). An example of the status block is shown in FIG.
[0182]
The target can store a minimum of 8 bytes and a maximum of 32 bytes of status information. In the case of the management ORB, since the status FIFO address is explicitly provided as a part of the ORB in the status FIFO field of FIG. 25, the target stores the status block at the designated address. Otherwise, the status block is stored in the status FIFO obtained from the fetch agent context. In the case of a command block ORB, the initiator provides the status FIFO address as part of the login request.
[0183]
Normally, the target responds to the ORB issued by the initiator by writing a status block to the status FIFO address. However, if a change occurs on the device side and affects the logical unit, the target will not respond even if there is no request from the initiator. It is also possible to return an unsolicited status. The status FIFO address in this case is a status FIFO address provided from the initiator when a login request is issued from the initiator.
[0184]
The operation of the initiator and target in SBP-2 will be described using the operation model of FIG.
[0185]
The operation of SBP-2 starts when the initiator issues a management ORB (login ORB) for a login request to the target. The target responds with a login response to the request from the initiator.
[0186]
When the login request is accepted, the head address of the command block agent register is returned as a login response from the target.
[0187]
When the login request is accepted, the target management agent accepts subsequent task management requests from the initiator. The initiator issues a task management ORB to exchange information necessary for executing the task with the target. The target responds to the ORB issued by the initiator by writing a status block in the status FIFO. However, if a change occurs on the device side and affects the logical unit, it will be voluntarily unsolicited even if there is no request from the initiator. As described above, the limited status can also be returned.
[0188]
Following the exchange related to task management, the initiator forms a necessary command block ORB (list) in its own memory area. Then, as shown in FIG. 31, the ORB to be communicated to the target is in the initiator by writing the ORB head address in the ORB pointer of the target command block agent register or hitting the doorbell register of the command block agent register. Let them know.
[0189]
In response to this, the target accesses the memory of the initiator based on the ORB head address information written in the ORB pointer as shown in FIG. 32, and sequentially processes the ORB.
[0190]
By the way, the task execution model includes an ordered model and an unordered model. In the ordered model, ORB is performed in the order of the list, and the completion status of the target is also returned in order. In the unordered model, there is no restriction on the execution order of ORB, but the initiator must be responsible for finally obtaining the same execution result in any order.
[0191]
Data transfer from the initiator to the target is performed by a read transaction from the target to the system memory, while data transfer from the target to the initiator is performed by a write transaction to the system memory. That is, the transfer of the data buffer is led by the target regardless of the direction. In other words, the target can read data from the system memory at a convenient pace. The initiator adds the ORB to the linked list by rewriting the next address of the last ORB in the list to the next ORB address even when the target is executing the ORB, and notifying the target by hitting the target doorbell register again. Can do. The target returns a completion status (status block) to the address of the initiator status FIFO. The initiator sees that the completion status (status block) is returned and knows that the execution of the target ORB by the target has been completed. The completed ORB can be removed from the task set link list (if the next ORB field is not null), the initiator will use the free resource and add the next command to the end of the command link list if necessary You may do it.
[0192]
In this way, the ORB is executed and the task is executed.
[0193]
If the task ends and there is no need to continue access, the initiator issues a logout ORB and the target responds to complete the logout.
[0194]
(15) Overview of SBP-3
SBP-3 (Serial Bus Protocol 3) has been standardized since the second half of 2000 for the purpose of supplementing the lack of functions in that SBP-2 was inefficient by adding SBP-2 and adding functions. It is.
[0195]
Typical functions expanded in SBP-3 are as follows.
1. Isochronous data transfer function
2. Node ID independent function for initiator / target identification by device handle
3. Bidirectional data transfer function in one ORB
Here, three of the above functions will be described.
[0196]
SBP-3 is backward compatible with SBP-2, and the basic data transfer sequence is as described in the outline of SBP-2. That is, data transfer from the initiator to the target is performed by a read transaction from the target to the system memory, while data transfer from the target to the initiator is performed by a write transaction to the system memory. The target reads out the ORB at a pace convenient to itself, and learns the type information of the transfer operation by decoding the contents of the ORB. The target decodes whether the transfer operation corresponding to the ORB is data transfer from the initiator to the target, data transfer from the target to the initiator, and to which system memory area in the initiator the transfer operation is performed. The corresponding transfer operation is performed. When the target completes the transfer operation specified by the ORB, the target returns a completion status (status block) to the status FIFO address of the initiator.
[0197]
In SBP-3, two types of command blocks ORB, that is, ORBs including commands such as data transfer commands and device control commands are defined. One is that the value of the request format field of the command block ORB is 0, which is the same as the command block ORB defined in SBP-2. As described in “(14) Outline of SBP-2”, the data descriptor indicating the address and size of the data buffer or page table referred to by the ORB, the data size field, and the next ORB field indicating the address of the next command block ORB And a field for designating parameters related to data transfer represented by a direction field indicating the data transfer direction with respect to the data buffer.
[0198]
The command block ORB newly defined in SBP-3 has a value of 1 in the request format field, and can be distinguished from the conventional ORB.
[0199]
The feature of this ORB is that two data buffers are referenced from one ORB.
[0200]
Two sets of fields relating to the data buffer, such as a data descriptor indicating the address and size of the data buffer or page table, a data size field, and a direction field, are prepared, and the two data buffers can be referred from the ORB.
[0201]
Using this ORB, one data buffer can be used as a bidirectional ORB by using it as a buffer for writing to the target and the other data buffer as a buffer for reading from the target.
[0202]
The initiator forms the necessary command block ORB list in its own memory area, appends the bidirectional ORB as described above, and writes the head address of the ORB list to the ORB pointer of the target command block agent register or the command block Strike the doorbell register of the agent register to inform the initiator that there is an ORB to communicate with. The target accesses the memory of the initiator based on the ORB head address information written in the ORB pointer, fetches the ORB, and sequentially processes it.
[0203]
The target that fetched the bidirectional ORB performs data transfer processing for each of the two designated data buffers. The direction field corresponding to the buffer on one side is 0, and the target accesses the data buffer on the system memory indicated by the data descriptor and reads the write data therefrom. The direction field corresponding to the other buffer is 1, and the target accesses the data buffer on the system memory indicated by the data descriptor and writes the data requested by the command there.
[0204]
When both data buffer accesses are completed, the target returns a completion status (status block) to the address of the initiator status FIFO and notifies the completion of execution of the ORB.
[0205]
FIG. 33 is a diagram illustrating the operation of the command block ORB in SBP-3. Compared to SBP-2 shown in FIG. 32, SBP-3 has two lines indicating data buffer access to one ORB, and SBP-2 can only access one data buffer. The point has been changed. The ability to access the two data buffers independently allows two data channels from the initiator to the target to be applied to one ORB. The direction of data flow to the data buffer can be defined by each data buffer. That is, two data channels can be used for data transmission from the initiator to the target, one can be used for data transmission from the initiator to the target, and the other can be used for data transmission from the target to the initiator. Of course, two data channels can be used for data transmission from the target to the initiator. Further, when used in a host and a printer, one can be used for print data from the host to the printer, and the other can be used to send status information from the printer to the host.
[0206]
FIG. 34 shows details of the command block ORB in the case of holding two data buffers of SBP-3. Unlike SBP-2, two data descriptors and two buffer information fields are prepared in order to handle two sets of data buffers. The direction of each data buffer can be specified in the field indicated by “d” in the figure. The content is the same as that of SBP-2, where 0 indicates the direction from the initiator to the target, and 1 indicates the direction from the target to the initiator.
[0207]
<Information processing system according to this embodiment>
FIG. 1 is a diagram showing an information processing system according to this embodiment, and shows a host computer (hereinafter referred to as a host) 1a and a printer 1b connected by IEEE1394.
[0208]
Communication between the host 1a and the printer 1b is performed using the SBP (Serial Bus Protocol) -3 protocol which is a typical data transfer protocol used on the IEEE1394 interface, and a communication channel for transferring data between the host and the printer. As shown in FIG.
[0209]
In FIG. 1, a host 1a is a system that communicates with a printer device 1b that is a target of SBP-3 as an initiator using the SBP-3 protocol. In the case of this communication system, host-printer communication is performed based on a printer control communication command protocol defined in advance as an upper command set of the SBP-3 protocol, and processing according to the command is performed.
[0210]
The printer 1b has a plurality of functions that respectively provide a printer control sent from the host 1a, a function for receiving and processing print data, and a function for sending current printer status data to the host in response to the control to the printer 1b. Data transfer channels CH1 and CH2 are provided. Also, a management agent MA for processing management requests such as establishment and disconnection of communication sessions for these data transfer channels is provided.
[0211]
Each of the data transfer channels CH1 and CH2 performs data transfer by utilizing an ORB having a dual data descriptor defined by the SBP-3 protocol. Each channel performs data transfer by a data buffer specified by two data descriptors. The execution state of the ORB fetched by the fetch agent FA is managed by the command block agent CA, and predetermined processing for the two data buffers specified by the ORB is written or read by the execution agents EA0 and EA1. The The fetch agent has a mechanism for executing the predetermined processing by sequentially processing the ORB issued from the initiator in accordance with the ordered model of SBP-2 / 3.
[0212]
In this embodiment, by using SBP-3 as a printer control communication command protocol, the data buffers specified by two data descriptors in the ORB are allocated as data transfer channels, respectively, and printing is performed on one data transfer channel. Data is defined as a model specification in which printer control commands are transferred to the other data transfer channel.
[0213]
<Status block according to this embodiment>
Normally, in SBP-3, when the processing for the data buffer specified by the ORB is completed, the target issues a completion status (status block) to the status FIFO address of the initiator as a completion notification for notifying the initiator of the processing. . However, as shown in FIG. 33, when two data buffers are specified using two data descriptor fields in one ORB, a completion status (status block) is issued only when both data buffer processes are completed. Is done. Even if the access to one data buffer ends normally, if the other data buffer access is not completed, the completion notification for that ORB cannot be sent to the initiator of SBP-3, and data transfer as a logical unit is delayed. End up. For this reason, when data transmission / reception cannot be performed on one of the data transfer channels for some reason, or when data transfer on one of the data transfer channels is slower than the other channels, the channel being transferred normally is fast. The other channel will be affected.
[0214]
In the system according to the present embodiment, if one data buffer is used for print data and the other is used for status, the status cannot be returned to the host until the printer receives all the print data data buffers. appear. This means that status information cannot be received at any time.
[0215]
Therefore, in the present embodiment, a status block as shown in FIG. 35 is issued to notify the completion of access for each data buffer.
[0216]
FIG. 35 is a diagram showing a completion status (status block) issued when data buffer processing is completed in the printer control communication command protocol according to the present embodiment.
[0217]
As shown in FIG. 35, in the status block, a, b1, and b2 are defined as fields indicating the completion status for each data buffer in the command set dependent field.
[0218]
a, b1, and b2 respectively represent data buffers, b1 corresponds to the data buffer indicated by the first data descriptor shown in FIG. 34, and b2 indicates the data buffer indicated by the second data descriptor. It corresponds. a corresponds to both data buffers indicated by these two data descriptors. A value of 0 or 1 is set in each of the fields a, b1, and b2, indicating that the corresponding buffer is completed when the value is 1, and indicating that the corresponding buffer is not completed when the value is 0. That is, when 1 is designated for a, it indicates that data communication with respect to the two buffers has been completed simultaneously. By setting values for the three fields a, b1, and b2, completion of the first buffer, completion of the second buffer, and completion of both buffers 1 and 2 can be notified individually or simultaneously.
[0219]
FIG. 36 is a diagram showing the operation of the command block ORB when such a status block is adopted. As shown in the figure, access to the status FIFO is performed a plurality of times (in this case, twice). Here, access to the status FIFO is performed in the status block shown in FIG. 35, and 1 is set in any bit of a, b1, and b2. For example, when only the processing for the second buffer is completed, 1 is set for b2 and 0 is set for b1 in the first status block, and when the processing for the first buffer is completed, the second status block Thus, 0 is set to b2 and 1 is set to b1. Thus, the status block is transmitted individually for each buffer. Since both b1 and b2 are notified of completion, the completion of the ORB being processed is notified. Further, by setting 1 to a, it is possible to end data communication with respect to two buffers with one status block.
[0220]
As described above, in the information processing system according to the present embodiment, it is possible to specify a completion notification for individual data buffers in a command execution process having a plurality of data buffers in a command block, thereby further controlling the buffer. Can be done in detail. In addition, since it is possible to determine that the command block is completed when notifications of completion of a plurality of data buffers are simultaneously obtained, the number of completion notifications can be reduced. In addition, it is possible to notify completion of all data buffers at one time, so that the completion notification can be simplified and compatibility with the prior art can be maintained.
[0221]
As a result, since the status can be written to the status FIFO independently for each data buffer, it is possible to realize a printing system that can continuously return only the status to the host independently of the print data.
[0222]
(Other embodiments)
Although the embodiments of the present invention have been described in detail above, the present invention may be applied to a system constituted by a plurality of devices or may be applied to an apparatus constituted by one device. In the above embodiment, an example in which IEEE 1394 is used as a communication control bus has been described. However, the present invention is not limited to this, and a bus of another standard such as USB may be used.
[0223]
In the present invention, a software program that realizes the functions of the above-described embodiments is directly or remotely supplied to a system or apparatus, and the computer of the system or apparatus reads and executes the supplied program code. Including the case where it is also achieved by. In that case, as long as it has the function of a program, the form does not need to be a program.
[0224]
Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. That is, the claims of the present invention include the computer program itself for realizing the functional processing of the present invention.
[0225]
In this case, the program may be in any form as long as it has a program function, such as an object code, a program executed by an interpreter, or script data supplied to the OS.
[0226]
As a recording medium for supplying the program, for example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card ROM, DVD (DVD-ROM, DVD-R) and the like.
[0227]
As another program supply method, a client computer browser is used to connect to an Internet homepage, and the computer program of the present invention itself or a compressed file including an automatic installation function is downloaded from the homepage to a recording medium such as a hard disk. Can also be supplied. It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the claims of the present invention.
[0228]
In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and key information for decryption is downloaded from a homepage via the Internet to users who have cleared predetermined conditions. It is also possible to execute the encrypted program by using the key information and install the program on a computer.
[0229]
In addition to the functions of the above-described embodiments being realized by the computer executing the read program, the OS running on the computer based on the instruction of the program is a part of the actual processing. Alternatively, the functions of the above-described embodiment can be realized by performing all of them and performing the processing.
[0230]
Furthermore, after the program 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, the function expansion board or The CPU or the like provided in the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.
[0231]
【The invention's effect】
According to the present invention, efficient data transfer can be performed using two channels such as an IEEE 1394 bus.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a host / printer communication system according to the present invention.
FIG. 2 is a diagram showing a network configuration of a 1394 serial bus.
FIG. 3 is a diagram showing components of a 1394 serial bus according to the present invention.
FIG. 4 is a diagram showing a service capable of providing a link layer of a 1394 serial bus according to the present invention.
FIG. 5 is a diagram showing a service capable of providing a transaction layer of a 1394 serial bus according to the present invention.
FIG. 6 is a diagram for explaining an address space in a 1394 interface;
FIG. 7 is a diagram showing an address and a function of information stored in a CSR core register in the 1394 interface.
FIG. 8 is a diagram showing the address and function of information stored in a serial bus register in the 1394 interface.
FIG. 9 is a diagram showing a configuration ROM in the minimum format in the 1394 interface.
FIG. 10 is a diagram showing a general configuration ROM in a 1394 interface.
FIG. 11 is a diagram showing an address and a function of information stored in a serial bus device register in the 1394 interface.
FIG. 12 is a cross-sectional view of a communication cable conforming to the IEEE 1394 standard.
FIG. 13 is a diagram for explaining a DS-Link encoding method.
FIG. 14 is a diagram showing a basic sequence from the start of bus reset to node ID assignment processing.
FIG. 15 is a diagram showing a basic sequence from the start of bus reset to node ID assignment processing;
FIG. 16 is a diagram showing a basic sequence from the start of bus reset to node ID assignment processing;
FIG. 17 is a flowchart for explaining in detail the processing in step S1505 shown in FIG. 15 (that is, processing for automatically assigning the node ID of each node).
FIG. 18 is a diagram showing a configuration of a self ID packet in a 1394 interface.
FIG. 19 is a diagram for explaining arbitration in a 1394 network.
FIG. 20 is a diagram illustrating a case where an isochronous transfer mode and an asynchronous transfer mode are mixed in one communication cycle.
FIG. 21 is a diagram showing a format of a communication packet transferred based on an isochronous transfer mode.
FIG. 22 is a diagram showing a packet format of asynchronous transfer according to the present invention.
FIG. 23 is a diagram showing ORB types in SBP-2.
FIG. 24 is a diagram showing a format of a command block ORB in SBP-2.
FIG. 25 is a diagram showing a format of a management ORB in SBP-2.
FIG. 26 is a diagram showing a link list of a command block ORB in SBP-2.
FIG. 27 is a diagram showing direct access of a data buffer in SBP-2.
FIG. 28 is a diagram showing the use of a page table in SBP-2.
FIG. 29 is a diagram showing a format of a status FIFO in SBP-2.
FIG. 30 is a diagram illustrating a login operation in SBP-2.
FIG. 31 is a diagram showing an initial operation of task execution in SBP-2.
FIG. 32 is a diagram showing an operation of a command ORB in SBP-2.
FIG. 33 is a diagram showing the operation of a command ORB in SBP-3.
FIG. 34 is a diagram showing a format of a command block ORB in SBP-3.
FIG. 35 is a diagram showing a format of a status block in the information processing system as an embodiment of the present invention.
FIG. 36 is a diagram showing an operation of a command ORB in the information processing system as an embodiment of the present invention.

Claims (8)

An information processing system including first and second devices connected by a communication control bus,
The first device is:
Assign multiple data buffers to one command block,
The second device is
Data communication means for performing data communication with respect to at least one of the plurality of data buffers according to the command block;
When data communication with respect to any one of the plurality of data buffers is completed by the data communication means, information for specifying one data buffer for which the data communication has been completed and data in the plurality of data buffers The first device is notified of a status including information for specifying a data buffer for which communication has not been completed, and when the data communication means completes data communication for all of the plurality of data buffers, A completion notifying means for notifying the first device of a status indicating that data communication with the data buffer has been completed;
An information processing system comprising: Said communication control bus is compliant with IEEE1394, the in between the first device and the second device, information of claim 1, wherein the data communication serial bus protocol 3 as the communication protocol Processing system. 3. The information processing system according to claim 1, wherein the completion notification unit issues a status indicating a data buffer in which data communication has been completed among the data buffers to a status FIFO of the first device. . The completion notifying unit, an information processing system according to claim 1, 2 or 3 with the status block, and notifies that the data communication has been completed. A communication method between first and second devices connected by a communication control bus, wherein a plurality of data buffers are allocated to one command block transmitted from the first device to the second device, and the second device Performs data communication with respect to at least one of the plurality of data buffers according to the command block, and the data communication is completed when the data communication with respect to any one of the plurality of data buffers is completed by the data communication . A status including information for specifying one data buffer and information for specifying a data buffer for which data communication is not completed among the plurality of data buffers is notified to the first device, and the data communication If data communication to all of the plurality of data buffers is completed by Communication method and notifies the status indicating that the data communication has been completed with respect to Tabaffa the first device. An information processing apparatus connected to another device via a communication control bus,
Data communication means for performing data communication with respect to at least one of the plurality of data buffers in accordance with the command block to another device in which a plurality of data buffers are allocated to one command block;
When data communication with respect to any one of the plurality of data buffers is completed by the data communication means, information for specifying one data buffer for which the data communication has been completed and data in the plurality of data buffers The first device is notified of a status including information for specifying a data buffer for which communication has not been completed, and when the data communication means completes data communication for all of the plurality of data buffers, A completion notifying means for notifying the other device of a status indicating that data communication to the data buffer is completed;
An information processing apparatus comprising: A program for causing a computer to implement the communication method according to claim 5 . A computer-readable storage medium storing the program according to claim 7 .

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