JP4205975B2 - Bus bridge device and data transfer control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a bus bridge device that bridges a plurality of electronic devices having different bus interfaces and controls data transfer between these devices, and a data transfer control method thereof, and more particularly, to a host device having an IEEE1394 interface. This belongs to the technology of a bus bridge device suitable for data transfer between a computer and a peripheral device equipped with an IDE interface.
[0002]
[Prior art]
  Generally, an IDE (Integrated Device Electronics) interface that is standardly installed in a personal computer is inexpensive, and is often provided as the first model of a built-in storage device such as a built-in optical disk drive or hard disk drive. Compared to this, next-generation interfaces such as IEEE (Institute of Electrical and Electronics Engineers) 1394 and USB 2.0 (universal serial bus) are expensive and are not widely used at present. Therefore, when connecting a general operating system such as Windows (registered trademark) or MacOS (registered trademark) and a built-in storage device through the IEEE 1394 interface, rather than developing a new built-in storage device equipped with the IEEE 1394 interface. It is more cost-effective to connect an already-developed built-in storage device having an IDE interface to an IEEE 1394 interface via an IDE bridge (bridge device), which is currently the mainstream.
[0003]
  On the other hand, for the purpose of cost reduction, the built-in storage device itself is often not equipped with a temperature management fan or a fan drive control output terminal. For this reason, for example, a fan is attached to the housing of the internal storage device, and the temperature of the internal storage device is managed by driving and controlling the fan from the IEEE1394 interface side (see, for example, Patent Document 1).
[0004]
[Patent Document 1]
      Japanese Patent Laid-Open No. 10-254811
[0005]
[Problems to be solved by the invention]
  Generally, the temperature information of the internal storage device can be obtained by issuing a vendor unique command for the IDE interface to the internal storage device. However, if the vendor unique command is issued from the IEEE 1394 interface side to the internal storage device while the computer is reading data from the internal storage device, the data reading may be temporarily interrupted. That is, by issuing a vendor unique command from the IEEE 1394 interface side, there is a possibility that the transfer rate is lowered and the video and audio being reproduced are interrupted.
[0006]
  In view of the above problems, the present invention bridges a plurality of electronic devices having different bus interfaces and bridges a built-in storage device without lowering the data transfer rate when transferring data between these devices. It is an object of the present invention to provide a bus bridge device capable of performing interrupt control such as temperature information acquisition and the like, and a data transfer control method enabling such interrupt control.
[0007]
[Means for Solving the Problems]
  Means taken by the present invention to solve the above problems is provided between the first device and the second device, and as a bus bridge device for transferring data between the first device and the first device, From the first transfer control unit that communicates via the first bus interface, the second transfer control unit that communicates with the second device via the second bus interface according to a given command, and the first device With reference to the issued first command, a command issued after the first command is predicted, the predicted command is given to the second transfer control unit, and the predicted command and the command A prefetch control unit that determines whether or not a second command that is actually issued after the first command matches, and the second device by the second transfer control unit according to the prediction command Luo prefetched preread data, a storage unit for temporarily storing, and that a interrupt control unit to interrupt control with respect to the second device. Here, when the first read control unit determines that the prediction command matches the second command by the prefetch control unit, the first transfer control unit stores the prefetch data stored in the storage unit as the first transfer control unit. It shall be transferred to the device. The interrupt control unit applies the interrupt control while the prefetch data is being transferred from the storage unit by the first transfer control unit.
[0008]
  According to the present invention, in accordance with the prediction command predicted from the first command by the prefetch control unit, data is prefetched from the second device by the second transfer control unit, and the prefetch data is temporarily stored in the storage unit. . When the prediction command matches the second command actually issued after the first command from the first device, the first transfer control unit stores the prefetched data stored in the storage unit as the first command. 1 device. During the transfer of the prefetched data, the second transfer control unit and the second device are not operating, that is, in an idle state, and interrupt control is possible. Therefore, during this idle state, the interrupt control unit applies interrupt control to the second device. Thereby, interrupt control can be applied to the second device without lowering the data transfer rate between the first and second devices.
[0009]
  Preferably, the interrupt control unit monitors the amount of prefetched data stored in the storage unit and applies the interrupt control when it is determined that a predetermined amount or more of unread prefetched data remains in the first device. Shall.
[0010]
  The means provided by the present invention is a bus bridge device that is provided between the first device and the second device and transfers data between them, and the first device and the first bus interface. A first transfer control unit that communicates with the second device according to a given command, a second transfer control unit that communicates with the second device through a second bus interface, and a first issued from the first device. The command issued after the first command is predicted, the predicted command is given to the second transfer control unit, and the predicted command and the first command It is assumed that a prefetch control unit that determines whether or not a second command that is actually issued later matches and an interrupt control unit that performs interrupt control on the second device are provided. Here, the second transfer control unit suspends prefetch processing of data from the second device according to the prediction command, and the prefetch control unit and the second command are preliminarily suspended. When a match with the command is determined, the prefetch process of the data is resumed. The interrupt control unit applies the interrupt control during a period from when the second transfer control unit pauses the data prefetching process to when it resumes.
[0011]
  According to the present invention, in accordance with the prediction command predicted from the first command by the prefetch control unit, the prefetch process of data from the second device is performed by the second transfer control unit, but this is temporarily stopped. The When the prediction command matches the second command actually issued after the first command from the first device, the data prefetching process is resumed, and the data is read from the second device. And transferred to the first device. At this time, since processing is resumed from the data transfer phase, no command overhead occurs. Therefore, using this interval, the interrupt control unit applies interrupt control to the second device. Thereby, interrupt control can be applied to the second device without lowering the data transfer rate between the first and second devices.
[0012]
  The second transfer control unit in each bus bridge device discards the process related to the prediction command when the prefetch control unit determines that the prediction command does not match the second command. It is preferable to communicate with the second device according to the second command.
[0013]
  The means provided by the present invention is a bus bridge device that is provided between the first device and the second device and transfers data between them, and the first device and the first bus interface. A first transfer control unit that communicates through the second bus controller, a second transfer control unit that communicates with the second device through a second bus interface, and a usage status of the first bus interface. The first and second transfer control units, comprising: an interrupt control unit that determines an idle time between commands issued from the device, and applies an interrupt control to the second device during the idle time. It is assumed that data transfer is performed between the first and second devices via an interrupt and interrupt control is applied to the second device.
[0014]
  According to the present invention, the use state of the first bus interface is monitored by the interrupt control unit, and the free time between the commands issued from the first device is determined. Then, using this idle time, interrupt control is applied to the second device. Thereby, interrupt control can be applied to the second device without lowering the data transfer rate between the first and second devices.
[0015]
  Note that the interrupt control unit in each bus bridge device described above preferably controls the third device connected to the bus bridge device based on the information obtained from the second device by the interrupt control. Specifically, the third device is assumed to be a temperature management fan for the second device. The interrupt control unit obtains temperature management information from the second device by the interrupt control, and controls the fan based on the temperature management information..
[0016]
  MaThe means provided by the present invention is provided between the first device and the second device, communicates with the first device through the first bus interface, and communicates with the second device and the second device. The first command issued from the first device is referred to as a bus bridge device that communicates through the bus interface and transfers data between the first and second devices. A command to be issued later is predicted, and a part of the process is executed as a prefetch process for data transfer from the second device to the first device according to the predicted command predicted, and the first When the second command issued after the first command from the device matches the prediction command, the remaining processing of the data transfer is executed, and the second device is executed during the remaining processing. for It shall be multiplied by the interrupt control.
[0017]
  In each of the above bus bridge devices, specifically, the first bus interface is assumed to conform to IEEE (Institute of Electrical and Electronics Engineers) 1394 standard or USB (universal serial bus) standard. The second bus interface conforms to the IDE (Integrated Device Electronics) standard.
[0018]
  On the other hand, the means taken by the present invention to solve the above problem is provided between the first device and the second device, communicates with the first device through a first bus interface, and In a bus bridge device that communicates with a second device through a second bus interface and performs data transfer between the first and second devices, the first device is used as a data transfer control method for controlling the data transfer. Referring to the first command issued from the first device, predicting a command issued after the first command, and from the second device to the first device according to the predicted command predicted A step of executing a part of the process as a pre-reading process, and a second command issued after the first command from the first device includes When matched with the command, and performing the remaining processes of the data transfer, during execution of the remaining processing, it is assumed that a step of interrupting the control to the second device.
[0019]
  Preferably, the prefetch process includes a step of issuing the prediction command to the second device, a step of receiving data transferred from the second device, and a step of storing the received data in a storage unit It shall have. Further, the remaining processing includes a step of transferring data stored in the storage means to the first device.
[0020]
  Preferably, the prefetching process includes a step of issuing the prediction command to the second device. The remaining processing includes a step of receiving data transferred from the second device, a step of storing the received data in a storage unit, and a step of storing the data stored in the storage unit in the first unit. It is assumed to have a step of transferring to the device.
[0021]
  The data transfer control method further includes the step of obtaining information related to control of the third device connected to the bus bridge device from the second device by the interrupt control, and the third device. It is preferable to have a step of controlling the third device based on the information related to the control of the second device.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0023]
  (First embodiment)
  FIG. 1 shows a configuration of a bus bridge device according to a first embodiment of the present invention. The bus bridge device 10A according to the present embodiment includes an IEEE 1394 host device (host device) 31 as a first device having an IEEE 1394 interface 21 as a first bus interface, and an IDE interface 22 as a second bus interface. Bridge the internal storage device 32 as the second device, control data transfer between these devices, and control the temperature of the internal storage device 32 by controlling the fan 33 as the connected third device It is.
[0024]
  The bus bridge device 10A includes a PHY 11 and a LINK 12 as IEEE 1394 interface units connected to the host device 31 side, a first transfer control unit 13 that performs data transfer processing with the host device 31, and an internal storage device 32. A second transfer control unit 14 that performs data transfer processing between them, a storage unit 15, a prefetch control unit 16 that controls the second transfer control unit 14, and first and second transfer control units 13 and 14. And a CPU 17 serving as an interrupt control unit for controlling the fan 33.
[0025]
  The first transfer control unit 13 performs IEEE 1394 packet control via the PHY 11 and the LINK 12, and converts a packet given from the host device 31 into a packet including a command and data for the internal storage device 32 and other packets. Distinguish between them and process appropriately. Specifically, the first transfer control unit 13 analyzes the content of the IEEE 1394 packet and starts from the CDB (command data block) in the ORB (operation request block, see FIG. 2) to the internal storage device 32. Command (SCSI command, see FIG. 3). Then, this extracted command is sent to the second transfer control unit 14.
[0026]
  The second transfer control unit 14 receives a command for the internal storage device 32 from the first transfer control unit 13 and issues the command to the internal storage device 32 through the IDE interface 22 to perform data transfer processing.
[0027]
  The storage unit 15 temporarily stores transmission data addressed to the host device 31 read from the internal storage device 32.
[0028]
  The prefetch control unit 16 predicts a command issued from the host device 31 to the internal storage device 32, and gives the prediction command to the second transfer control unit 14 to control the second transfer control unit 14.
[0029]
  The CPU 17 controls the first and second transfer control units 13 and 14 to manage the IEEE 1394 interface process and the IDE interface process, and appropriately controls the fan 33.
[0030]
  The operation of the bus bridge device 10A of the present embodiment configured as described above will be described with reference to the timing chart of FIG.
[0031]
  First, an ORB packet including CDB 1 is output from the host device 31 to the IEEE 1394 interface 21. The first transfer control unit 13 analyzes this packet, extracts the command 1 as the first command, and sends the command 1 to the second transfer control unit 14. Then, the first transfer control unit 13 waits for a response from the second transfer control unit 14. At this time, the transfer parameter in the ORB is set in the first transfer control unit 13 by the CPU 17.
[0032]
  The second transfer control unit 14 issues the command 1 addressed to the internal storage device 32 given from the first transfer control unit 13 to the internal storage device 32 through the IDE interface 22 and starts data transfer from the internal storage device 32. Receive a request. Upon receiving the data transfer start request, the second transfer control unit 14 issues a command completion notification to the first transfer control unit 13 and makes a data transfer start request to instruct data transfer. Then, the data 1 transferred from the internal storage device 32 through the IDE interface 22 is sent to the first transfer control unit 13 via the storage unit 15. The first transfer control unit 13 forms the given data into an IEEE 1394 packet, and transmits the data to the host device 31 through the IEEE 1394 interface 21.
[0033]
  When data is transferred from the internal storage device 32 to the host device 31, the data transfer from the internal storage device 32 is completed first. That is, when data 1 to data n are read from the built-in storage device 32, the first transfer control unit 13 is still transferring data stored in the storage unit 15. Therefore, the prefetch control unit 16 refers to the command 1 issued from the second transfer control unit 14 to the internal storage device 32 earlier, predicts the next command to be issued by the host device 31, and executes the prediction command (command 2) is given to the second transfer control unit 14. At this time, the first transfer control unit 13 is in the process of data transfer with the host device 31 or the data transfer end process, but the second transfer control unit 14 and the prefetch control unit 16 are related to this. It works independently.
[0034]
  Here, an example of command prediction will be described. When reading video or audio data from the internal storage device 32 in accordance with a command issued by the host device 31, it is common to divide and read the data into fixed lengths of about 32K to 64K bytes instead of reading all the data at once. is there. In such a case, the start address of the data specified in the next command to be issued by the host device 31 and the start address of the data specified by the command issued first by the host device 31 and the data length thereof are read. Data length can be predicted. In particular, when the built-in storage device 32 reproduces a music CD, DVD-Video, or the like, data is often arranged at continuous addresses in these media, so it is extremely difficult to predict an address related to reading. Easy.
[0035]
  In response to the command 2 issued by the prefetch control unit 16, when a data transfer request is sent from the internal storage device 32 to the second transfer control unit 14, the data transfer between the second transfer control unit 14 and the internal storage device 32 is performed. The data transfer is started. Data 1 to data n transmitted from the internal storage device 32 in this data transfer are stored in the storage unit 15 via the second transfer control unit 14. This process is arbitrarily repeated until the next command is issued from the host device 31 to the internal storage device 32.
[0036]
  When the processing of the ORB packet including CDB1 is completed, the host device 31 next outputs the ORB packet including CDB2. As before, the CPU 17 sets the parameters of the first transfer control unit 13, the second transfer control unit 13 extracts the second command addressed to the internal storage device 32, and the second transfer control unit 14. Sent to. At this time, the prefetch control unit 16 determines whether or not the next issued command from the host device 31 matches the predicted command previously predicted. When it is determined that they match, a command completion notification is sent to the first transfer control unit 13 via the second transfer control unit 14 and a data transfer start request is sent to the first transfer control unit 13 for data transfer. Give instructions. At this time, no command is issued to the internal storage device 32.
[0037]
  When receiving the data transfer start request, the first transfer control unit 13 reads the data 1 to data n stored in the storage unit 15 and transfers them to the host device 31. Here, the data stored in the storage unit 15 is data prefetched from the internal storage device 32 based on the command predicted by the prefetch control unit 16.
[0038]
  While the prefetched data is being read from the storage unit 15, the second transfer control unit 14, the IDE interface 22, and the built-in storage device 32 are in an idle state where they are not operating. Therefore, a temperature information acquisition command is issued from the CPU 17 to the internal storage device 32 using this interval. Thereby, the temperature information can be acquired from the internal storage device 32 without reducing the data transfer rate from the internal storage device 32 to the host device 31.
[0039]
  As described above, according to the present embodiment, interrupt control for the internal storage device 32 such as acquisition of temperature information can be performed without reducing the data transfer rate between the host device 31 and the internal storage device 32. Thus, for example, during playback of moving image data read from the internal storage device 32 in the host device 31, the temperature of the internal storage device 32 is controlled by appropriately controlling the fan 33 without interrupting the playback of the moving image. Can do.
[0040]
  The CPU 7 monitors the amount of data stored in the storage unit 15 and issues a temperature information acquisition command when determining that there is a sufficient amount of data that has not yet been read by the host device 31 beyond a predetermined amount. It is preferable to do. By doing so, it is assured that the processing related to the temperature information acquisition is completed within the period in which the second transfer control unit 14, the IDE interface 22 and the internal storage device 32 are in the idle state. As a result, it is possible to avoid a decrease in the data transfer rate between the host device 31 and the built-in storage device 32 more reliably.
[0041]
  Further, when the prefetch control unit 16 determines that the prediction command and the next issued command from the host device 31 do not match, the prefetch control unit 16 controls the IDE interface 22 via the second transfer control unit 14, and the built-in storage device 32. The second transfer control unit 14 preferably issues a new issue command to the internal storage device 32 so that the previously issued prediction command is discarded. Thus, even if the prefetch control unit 16 makes a prediction error, the data transfer process can be returned to a normal state.
[0042]
  (Second Embodiment)
  FIG. 5 shows the configuration of the bus bridge device according to the second embodiment of the present invention. In the figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals as those in FIG. As can be seen from FIG. 5, the bus bridge device 10B of the present embodiment has a configuration in which the storage unit 15 in the bus bridge device 10A according to the first embodiment is omitted. Hereinafter, the operation of the bus bridge device 10B will be described with reference to the timing chart of FIG. Only differences from the bus bridge device 10A will be described.
[0043]
  The second transfer control unit 14 issues the command 2 predicted by the prefetch control unit 16 to the internal storage device 32, and then performs data transfer processing in the data transfer phase without actually prefetching data from the internal storage device 32. Is in a paused state. Then, the prefetch control unit 16 determines that the next issued command from the host device 31 matches the previously predicted command, and notifies the first transfer control unit 13 of the completion of the command. When instructed, the second transfer control unit 14 resumes the data transfer process that has been suspended. At this time, the command is not issued to the internal storage device 32, and the processing is resumed from the data transfer phase that has been suspended. As a result, the command overhead associated with the processing of the next issued command can be reduced. Then, during the reduced overhead period, the CPU 17 can apply interrupt control to the internal storage device 32.
[0044]
  As described above, according to the present embodiment, it is possible to avoid a decrease in the data transfer rate between the host device 31 and the built-in storage device 32 without providing a storage unit that pre-reads and stores data. Thereby, it becomes possible to implement with a smaller circuit scale than the bus bridge device 10A according to the first embodiment.
[0045]
  (Third embodiment)
  FIG. 7 shows a configuration of a bus bridge device according to the third embodiment of the present invention. In the figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals as those in FIG. As can be seen from FIG. 7, the bus bridge device 10 </ b> C of the present embodiment has a configuration in which the storage unit 15 and the prefetch control unit 16 in the bus bridge device 10 </ b> A according to the first embodiment are omitted. Hereinafter, the operation of the bus bridge device 10C will be described with reference to the timing chart of FIG. Only differences from the bus bridge device 10A will be described.
[0046]
  The CPU 17 monitors the use status of the IEEE 1394 interface 21, that is, the frequency of command issuance from the host device 31 via the first transfer control unit 13, and determines whether the host device 31 has not issued an ORB. In this case, since the second transfer control unit 14 is in an idle state, the CPU 17 drives the second transfer control unit 14 to issue a temperature information acquisition command to the internal storage device 32. Thereby, the temperature information of the built-in storage device 32 can be obtained using the free time that the host device 31 does not issue the ORB.
[0047]
  For example, a so-called isochronous gap related to isochronous transfer can be used to determine the free time between commands issued to the IEEE 1394 interface 21. In isochronous transfer, since packet transfer is performed at an interval of 125 μs, it is possible to determine an idle time (isochronous gap) until transfer of a certain packet is completed and transfer of the next packet is executed. Therefore, it is possible to apply interrupt control to the built-in storage device 32 using this free time. However, since the current built-in storage device 32 has insufficient drive response performance, it is difficult to complete interrupt control within the isochronous gap. However, since the drive response performance is expected to improve in the future, it is possible to complete the interrupt control within the isochronous gap.
[0048]
  As described above, according to the present embodiment, the usage status of the IEEE 1394 interface 21 can be monitored, and interrupt control can be applied to the internal storage device 32 during the idle time when the host device 31 does not issue the ORB. As a result, the interrupt control for acquiring the temperature information can be applied to the internal storage device 32 without reducing the data transfer rate between the host device 31 and the internal storage device 32. Furthermore, the circuit area can be further reduced as compared with the bus bridge devices 10A and 10B according to the first and second embodiments.
[0049]
  (Reference example)
  FIG.Reference exampleThe structure of the bus bridge apparatus which concerns on this is shown. In the figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals as those in FIG. As can be seen from FIG.Reference exampleThe bus bridge device 10D has a configuration in which the storage unit 15, the prefetch control unit 16, and the CPU 17 in the bus bridge device 10A according to the first embodiment are omitted. Hereinafter, only a difference of the bus bridge device 10D from the bus bridge device 10A will be described.
[0050]
  Regarding the IDE specification, there are INTRQ signal and STATUS register information as information exchanged between the internal storage device 32 and the second transfer control unit 14. The second transfer control unit 14 associates the information with each of the command processing phase, the data transfer phase, and the idle phase in which nothing is transmitted / received, so that the information provided from the internal storage device 32 is a temperature management request. Or whether it is a normal signal and data processing request.
[0051]
  In the command processing phase and the data transfer phase, the second transfer control unit 14 acquires the STATUS register information of the IDE interface 21 from the internal storage device 32 when receiving the INTRQ signal from the internal storage device 32. At this time, the internal storage device 32 can request control for temperature management from the second transfer control unit 14 by expressing the temperature management request by the flag included in the STATUS register information. Upon receiving this request, the second transfer control unit 14 controls the fan 33 to manage the temperature of the internal storage device 32.
[0052]
  Also in the idle phase, similarly to the above, the second transfer control unit 14 receives the INTRQ signal to obtain STATUS register information including a flag indicating a temperature management request from the internal storage device 32, and based on this. Then, the fan 33 is controlled.
[0053]
  This is the bookReference exampleAccording to this, temperature management information is obtained from the internal storage device 32 in response to an interrupt request (INTRQ signal) from the internal storage device 32, and the fan 33 can be controlled based on this. Therefore, it is not necessary to issue a temperature information acquisition command to the internal storage device 32, and the data transfer rate between the host device 31 and the internal storage device 32 is not reduced.
[0054]
  Instead of acquiring the STATUS register information according to the INTRQ signal from the built-in storage device 32, the second transfer control unit 14 polls the built-in storage device 32 and periodically obtains the STATUS information. It is also possible to do. Thereby, the second transfer control unit 14 can know the control timing of the fan 33 even if the INTRQ signal is not given.
[0055]
  In the above description, the bus bridge apparatuses 10A to 10D according to the present invention bridge the IEEE 1394 interface and the IDE interface. It is not limited. For example, USB 2.0 or the like may be used instead of IEEE 1394.
[0056]
  The second device of the present invention may be an external storage device instead of the internal storage device 32. The third device of the present invention may be other than the temperature management fan 33 of the internal storage device 32. Therefore, the interrupt control performed by the CPU 17 as the interrupt control unit on the internal storage device 32 is not limited to the acquisition of the temperature management information.
[0057]
【The invention's effect】
  As described above, according to the present invention, a data transfer rate is set for a bus bridge device that bridges a first device and a second device each having a different bus interface and controls data transfer between these devices. Interrupt control can be applied to the second device without lowering. Thereby, for example, when data is read from the second device and a moving image or the like is being reproduced, the temperature management information of the second device can be acquired without interrupting the image. And based on the acquired temperature management information etc., the temperature management etc. of a 2nd apparatus can be performed appropriately.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a bus bridge device according to a first embodiment of the present invention.
FIG. 2 is a diagram showing an ORB format according to IEEE 1394.
FIG. 3 is a diagram showing a format of a SCSI command.
FIG. 4 is a timing chart of the bus bridge device according to the first embodiment of the present invention.
FIG. 5 is a configuration diagram of a bus bridge device according to a second embodiment of the present invention.
FIG. 6 is a timing chart of the bus bridge device according to the second embodiment of the present invention.
FIG. 7 is a configuration diagram of a bus bridge device according to a third embodiment of the present invention.
FIG. 8 is a timing chart of the bus bridge device according to the third embodiment of the present invention.
FIG. 9Reference exampleIt is a lineblock diagram of the bus bridge device concerning.
[Explanation of symbols]
  10A, 10B, 10C, 10D Bus bridge device
  13 First transfer control unit
  14 Second transfer control unit
  15 Storage unit (storage means)
  16 Prefetch control unit
  17 CPU (interrupt controller)
  21 IEEE 1394 interface (first bus interface)
  22 IDE interface (second bus interface)
  31 Host device (first device)
  32 Internal storage device (second device)
  33 fans (third equipment)

Claims (13)

A bus bridge device that is provided between a first device and a second device and performs data transfer between them,
A first transfer control unit that communicates with the first device through a first bus interface;
A second transfer control unit that communicates with the second device through a second bus interface according to a given command;
Referring to a first command issued from the first device, predicting a command issued after the first command, providing the predicted command to the second transfer control unit; and A prefetch control unit that determines whether or not the prediction command and the second command actually issued after the first command match;
A storage unit that temporarily stores prefetched data prefetched from the second device by the second transfer control unit according to the prediction command;
An interrupt control unit that performs interrupt control on the second device,
The first transfer control unit transfers the prefetch data stored in the storage unit to the first device when the prefetch control unit determines that the prediction command matches the second command. Is what
The bus bridge device, wherein the interrupt control unit applies the interrupt control while the prefetch data is transferred from the storage unit by the first transfer control unit. The bus bridge device according to claim 1, wherein
The interrupt control unit monitors the amount of prefetched data stored in the storage unit and applies the interrupt control when it is determined that a predetermined amount or more of unread prefetched data remains in the first device. A bus bridge device. A bus bridge device that is provided between a first device and a second device and performs data transfer between them,
A first transfer control unit that communicates with the first device through a first bus interface;
A second transfer control unit that communicates with the second device through a second bus interface according to a given command;
Referring to a first command issued from the first device, predicting a command issued after the first command, providing the predicted command to the second transfer control unit; and A prefetch control unit that determines whether or not the prediction command and the second command actually issued after the first command match;
An interrupt control unit that performs interrupt control on the second device,
The second transfer control unit temporarily stops prefetch processing of data from the second device according to the prediction command, and the prefetch control unit performs the prediction command and the second command. When a match is determined, the prefetch processing of the data is resumed.
The bus bridge device, wherein the interrupt control unit applies the interrupt control during a period from when the second transfer control unit pauses the data prefetching process to when it resumes. The bus bridge device according to claim 1 or 3,
The second transfer control unit discards the process related to the prediction command when the prefetch control unit determines that the prediction command and the second command do not match, and according to the second command, A bus bridge device that communicates with the second device. A bus bridge device that is provided between a first device and a second device and performs data transfer between them,
A first transfer control unit that communicates with the first device through a first bus interface;
A second transfer control unit that communicates with the second device through a second bus interface;
The usage status of the first bus interface is monitored to determine a free time between commands issued from the first device, and interrupt control is applied to the second device during this free time. With an interrupt controller,
A bus bridge device, wherein data is transferred between the first and second devices via the first and second transfer control units, and interrupt control is applied to the second device. In the bus bridge device according to any one of claims 1, 3, and 5,
The bus bridge device, wherein the interrupt control unit controls a third device connected to the bus bridge device based on information obtained from the second device by the interrupt control. The bus bridge device according to claim 6, wherein
The third device is a fan for temperature management of the second device,
The bus bridge device, wherein the interrupt control unit obtains temperature management information from the second device by the interrupt control, and controls the fan based on the temperature management information. Provided between a first device and a second device, communicate with the first device through a first bus interface, communicate with the second device through a second bus interface, and And a bus bridge device for transferring data between the second devices,
Referring to a first command issued from the first device, predicting a command issued after the first command;
For data transfer from the second device to the first device according to the predicted command that has been predicted, a part of the processing is executed as a prefetching process,
When the second command issued after the first command from the first device matches the prediction command, the remaining processing of the data transfer is executed,
A bus bridge device that performs interrupt control on the second device during execution of the remaining processing. In the bus bridge device according to any one of claims 1, 3, 5 and 8 ,
The first bus interface is compliant with IEEE (Institute of Electrical and Electronics Engineers) 1394 standard or USB (universal serial bus) standard,
The bus bridge device according to claim 2, wherein the second bus interface conforms to an IDE (Integrated Device Electronics) standard. Provided between a first device and a second device, communicate with the first device through a first bus interface, communicate with the second device through a second bus interface, and And a method for controlling the data transfer in the bus bridge device that performs data transfer between the second devices,
Referring to a first command issued from the first device, predicting a command issued after the first command;
Executing a part of the process as a prefetch process for data transfer from the second device to the first device according to the predicted command predicted;
Executing a remaining process of data transfer when a second command issued after the first command from the first device matches the prediction command;
And a step of performing interrupt control on the second device during execution of the remaining processing. The data transfer control method according to claim 10 , wherein
The prefetching process includes
Issuing the prediction command to the second device;
Receiving data transferred from the second device;
Storing the received data in the storage means,
The remaining processing is
A data transfer control method comprising a step of transferring data stored in the storage means to the first device. The data transfer control method according to claim 10 , wherein
The prefetching process includes
Issuing the prediction command to the second device;
The remaining processing is
Receiving data transferred from the second device;
Storing received data in storage means;
A data transfer control method comprising a step of transferring data stored in the storage means to the first device. The data transfer control method according to claim 10 , wherein
Obtaining information related to control of a third device connected to the bus bridge device from the second device by the interrupt control;
And a step of controlling the third device based on information relating to the control of the third device.

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