KR20010018958A - apparatus and method for controlling bus in digital interface - Google Patents

Abstract

PURPOSE: The method and device for controlling a bus of a digital interface are provided to reduce a retry generated when mutually different channels are simultaneously allocated by using a lock transaction in more than two isochronous capable nodes on an IEEE(Institute of Electrical and Electronics Engineers) 1394 serial bus. In a new transaction, a channel allocation function is used at a channel allocation request, and a channel deallocation function is used at a channel deallocation request. CONSTITUTION: When performing lock transaction to an isochronous resource manager, new lock transaction is set up to an extended code of a lock request packet and a lock response packet. If lock transaction performed by other nodes does not changes a value of a channel for which allocation and deallocation is requested by a self node when performing the set lock transaction, channel allocation and deallocation are always performed from the isochronous resource manager. The new transaction uses a channel allocation function when requesting channel allocation and a channel deallocation function when requesting channel deallocation.

Description

Apparatus and method for controlling bus in digital interface}

The present invention relates to a digital interface, and more particularly, to a bus control apparatus and method for a digital interface.

The IEEE 1394 serial bus is automatically configured during bus initialization, and nodes can have multiple cable ports, and signal repeaters can be used to create a logical bus. repeater).

In the IEEE 1394 serial bus, data related to control and commands are transmitted in an Asynchronous Packet data structure, and real time data isochronous packet data. Packet data) structure, and FIG. 1 shows a physical connection between nodes connected by an IEEE 1394 serial bus.

In addition, the Isochronous Resource Manager of the IEEE 1394 serial bus provides three types of registers, which are 32-bit bits representing the bandwidth allocation used for isochronous data transmission. Bandwidth Available Register (BAR), 64-bit Channel Available Register (CAR) indicating the allocation status of the channel used for isochronous data transfer, and Bus Manager (Bus). There is a 32-bit Bus Manager ID Register (BMR) used to determine the Manager.

To change the values of these registers, a quadlet read transaction and a compare swap lock transaction are used.

Hereinafter, a bus control apparatus and method for a digital interface according to the prior art will be described with reference to the accompanying drawings.

1 is a diagram illustrating an example of topology of a node connected to an IEEE 1394 serial bus, in which node H (Node_H) is a root, a cycle master, a bus manager, and an isochronus. Is an isochronous resource manager, and node A and node B are isochronous capable nodes, and node H (isochronous resource manager) for transmitting isochronous data. Channel is allocated from Node_H).

2A to 2D are diagrams illustrating internal registers used by an isochronous capable node for channel allocation and assignment according to a bus control method of a digital interface according to the prior art.

Referring to the accompanying drawings, a bus control apparatus and method for a digital interface according to the related art made as described above are described in detail as follows.

First, as shown in FIG. 1, isochronous Capable Node A (or isochronous Capable Node B (Node_B)) on an IEEE 1394 serial bus transmits isochronous data. In order to check whether a channel required for transmission is available, the node H (Node_H), which is an IRM as shown in FIG. 2A, is shown through node E (Node_E) (or node C (Node_C) and node F (Node_F)). A quadlet read response subaction is performed with a channel avail register (CAR).

Then, in response to the Quadlet Read Response subaction, the Node H notifies the current state of the CAR by performing a Quadlet Read Request subaction.

Accordingly, Node A (or Node B (Node_B)) receiving the Quadlet Read Request subaction shows the arg_value field value of the quadlet data field in the request packet of the Quadlet Read Request subaction in FIG. 2B. After storing in its arg_register as shown, it searches whether a channel for transmitting isochronous data is available.

In other words, the first node (s) to transmit isochronous data is used for whether there is an unused channel, and the node (s) that were transmitting isochronous data before the bus reset occurred are assigned and used before the reset occurs. Search for available channels.

If the search result channel is available, Node A (or Node B) sets the corresponding bit of the channel to use to "0" and stores it in data_register as shown in FIG. After recording in the data_value field value of the request packet), a channel allocation is requested to the node H using a compar-swap lock request subaction together with the arg_value field in which the arg_value field value of the arg_register is recorded.

Then, the node H receiving the lock request packet stores its current CAR value (old_value) in old_register as shown in FIG. 2D and writes it in the old_value field of the response packet to perform a lock response subaction.

That is, the node H compares the arg_value field value of the lock request packet with the current CAR value and if it is the same, changes the value of the CAR to the data_value field value of the request packet (new_value). Otherwise, the node H does not change the CAR value. Execute Response Subaction.

Accordingly, when a node A (or node B (Node_B)) requesting channel allocation has successfully performed a lock transaction with a resp_complete value of a rcode (response code) of a lock response packet in the lock response subaction received from the node H, The value of the old_value field of the response packet is compared with the value of its arg_register.

If the comparison result is equal, Node A (or Node B (Node_B)) has succeeded in channel allocation. If not, other node (s) first performs a Compare-swap Lock Transaction of the CAR of the node H before the channel is allocated. After changing the value to determine that the channel has been allocated, the Compare-swap Lock Request subaction is retryed to request channel allocation again.

In this case, Node A (or Node B (Node_B)) does not need to perform the Quadlet read request subaction again because the old_value field value of the Lock Response packet indicates the current CAR value.

Meanwhile, a quadlet for requesting channel allocation to node H, which is an isochronous resource manager and a root node, through node E, node C, and node F to transmit isochronous data from node A and node B, respectively. When the Quadlet Read Response subaction of the Read Transaction is performed at the same time, Node H has a higher priority because Node A is closer to the root node than Node B. Therefore, Node H performs the Quadlet Read Request subaction corresponding to the Quadlet Read Response subaction of Node A.

That is, Node H, which receives the Quadlet Read Response subaction from Node A, performs a Quadlet Read Request subaction in response to this and informs Node A of its current CAR status.

After receiving the Quadlet Read Response subaction from the Node B, Node H performs a Quadlet Read Request subaction corresponding to the Quadlet Read Response subaction and informs Node B of the same CAR status as the CAR status informed to Node A.

Accordingly, Node A receiving the Quadlet Read Request subaction requests channel assignment to Node H using the Compare-swap Lock Request Subaction through the above process.

Then, the node H receiving the Compare-swap Lock Request Subaction compares the arg_value field value of the lock request packet with the current CAR value through the above-described procedure, and if so, changes the value of the CAR to the data_value field value of the request packet. new_value) and if it is not the same, the Lock Response Subaction is executed after the CAR value is not changed.

Accordingly, the node A, which has requested channel allocation, returns the old_value field value of the response packet when the lock transaction is successfully performed with the resp_complete value of the rcode (response code) of the lock response packet received from the node H. Compare with your arg_register value.

If the comparison result is equal, node A succeeds in channel allocation. If not, node A is allocated channel by changing the value of CAR of node H through Compare-swap Lock Transaction. After the determination, the compare-swap lock request subaction is retryed to request channel allocation again.

In this case, node A does not need to perform the quadlet read request subaction again because the old_value field value of the lock response packet indicates the current CAR value.

Subsequently, when the node A successfully performs the lock transaction, the node B receiving the quadlet read request subaction searches whether the channel for transmitting isochronous data is available through the above process.

If the search result is available, Node B sets the corresponding bit of the channel to be used as "0" and writes it in the data_value field of the lock request packet, and compare-swap lock request with the arg_value field which records the arg_value field value of arg_register. A channel assignment is requested to the node H using Subaction.

Then, the node H receiving the lock request packet records its current CAR value (new_value) in the old_value field of the response packet and then performs a lock response subaction.

That is, the node H compares the arg_value field value of the lock request packet with the current CAR value (new_value), and if it is not equal, does not change the value of the CAR and then changes the current CAR value (new_value) to the old_value field of the response packet. After recording, perform Lock Response Subaction.

Accordingly, the node A requesting channel allocation compares the old_value field value of the Lock Transaction received from the node H with its arg_register value.

Since the comparison result is not the same, before the node is allocated with the channel, the other node (s) first determines that the channel is allocated by changing the CAR value of the node H through the compare-swap lock transaction, and then executes the compare-swap lock request subaction. Retry and request channel allocation again.

In this case, Node B does not need to perform the Quadlet read request subaction again because the old_value field value of the Lock Response packet indicates the current CAR value.

However, the bus control apparatus and method of the digital interface according to the prior art have the following problems.

First, if two or more isochronous capacitive nodes simultaneously request different channel assignments, even if the requested channel is not in use, the channel is not allocated because the CAR value of the node, which is the isochronous resource manager, is changed according to the priority. Unsuccessful node (s) need to retry a lock transaction to receive a channel, causing unnecessary lock transactions.

Second, even in the case of a comparable-swap lock transaction for deallocation of an allocated channel after isochronous data transmission, only the node to which the channel is allocated transfers the channel. Retry lock transaction for channel transfer because channel available register value of node that is isochronous resource manager has been changed by other node (s) assigned to channel. Unnecessary lock transaction occurs.

Third, a bus reset has occurred due to the addition or removal of an arbitrary node, so that nodes that were transmitting isochronous data before the bus reset continued to transmit isochronous data after the bus reset. Even if it is necessary to reassign the channel allocated before the bus reset within a short time, it can occur when the channel cannot be reallocated within the predetermined time due to an unnecessary lock transaction.

Accordingly, the present invention has been made to solve the above problems, when at least two isochronous capacitive nodes on the IEEE 1394 serial bus to try to be allocated different channels at the same time using a lock transaction (lock transaction) It is an object of the present invention to provide a bus control device and a method of a digital interface for reducing a retry generated.

1 is a diagram illustrating an example of topology of a node connected by an IEEE 1394 serial bus

2A to 2D are diagrams illustrating internal registers used by an isochronous capable node for channel allocation and assignment according to a bus control method of a digital interface according to the prior art;

3A and 3B illustrate a transaction sequence for requesting channel allocation in one or two isochronous capable nodes connected to an IEEE 1394 serial bus according to a bus control method of a digital interface according to the present invention. showing an example of a sequence)

4A to 4F illustrate internal registers used by an isochronous capable node for channel allocation and assignment according to a bus control method of a digital interface according to the present invention.

5A to 5C are flowcharts illustrating a bus control method of a digital interface according to the present invention.

A bus control method of a digital interface according to the present invention for achieving the above object is a lock request packet and a lock request during a lock transaction with an isochronous resource manager. Setting a new lock transaction with an extended_code field of a lock response packet, and a lock transaction performed by another node when performing the set lock transaction; If the transaction does not change the value of the channel for which the allocation and assignment is required, the channel is always assigned and transferred from the isochronous resource manager (Isochronous Resource Manager).

The new lock transaction is a lock transaction using a channel allocation function (ch_alloc function) when a channel allocation request is requested, and a channel transfer function (ch_dealloc function) when a channel assignment request is requested.

In the step of allocating and transferring the channel, a lock transaction using the channel allocation function (ch_alloc function) is a value of a channel available register of the isochronous resource manager. The value of the desired channel is set to "1", the rest is set to "0", and the data is stored in the data register (data_register), and then the channel allocation lock request (Ch_alloc Lock Request subaction) is performed to the isochronous resource manager. It is characterized by sending to (Isochronous Resource Manager).

A feature of the bus control apparatus of the digital interface according to the present invention for achieving the above object is a channel available register of the isochronous resource manager (IRM) indicating the current channel allocation status. An arg register that stores a Register: CAR, an arg_value field value of a Read Response packet and an old_value field value of a Lock Response packet, and an arg value recorded in the arg register when a channel allocation request is made. A data register for storing only a value for changing a value of a CAR of an IRM node through a data_value field of a lock request packet by setting only a bit of a channel required by the lock request packet, and the lock request packet. Received IRM is old_value and data_value when requesting an assignment, and when the assignment is requested The register and the register, and the old_value and data_value when the channel allocation request is made for the value of the current CAR and the value of the data_value field of the lock request packet. It consists of a new_data register that stores the value of Exclusive_OR and the value of OR in both cities.

According to the present invention, a new lock transaction such as a ch_alloc function for a channel allocation request and a ch_dealloc function for a channel assignment request is used as an extended_code of a lock request packet and a lock response packet during a lock transaction for requesting channel assignment and assignment. By allowing the lock transaction performed by the user to assign and transfer the lock transaction, the performance of the entire IEEE 1394 serial bus can be improved by preventing unnecessary retry of the lock transition.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

Hereinafter, a preferred embodiment of a bus control apparatus and method for a digital interface according to the present invention will be described with reference to the accompanying drawings.

3A and 3B illustrate a transaction sequence for requesting channel allocation in one or two isochronous capable nodes connected to an IEEE 1394 serial bus according to a bus control method of a digital interface according to the present invention. 4A to 4F illustrate internal registers used by an isochronous capable node for channel allocation and assignment according to a bus control method of a digital interface according to the present invention. 5A to 5C are flowcharts illustrating a bus control method of a digital interface according to the present invention.

The bus control apparatus and method for a digital interface according to the present invention configured as described above will be described in detail with reference to the accompanying drawings.

First, as shown in FIG. 1, isochronous Capable Node A (or isochronous Capable Node B (Node_B)) on an IEEE 1394 serial bus transmits isochronous data. In order to check whether a channel required for transmission is available, the IRM as shown in FIG. 4A through the Node E (Node_E) (or Node C (Node_C) and Node F (Node_F)) as shown in FIG. 3A. A quadlet read response subaction is performed to a channel avail register (CAR) of an in-node H (Node_H) to transmit a channel allocation lock request packet.

Then, in response to the Quadlet Read Response subaction, the Node H notifies the current state of the CAR by performing a Quadlet Read Request subaction.

Accordingly, Node A (or Node B) receiving the Quadlet Read Request subaction shows the arg_value field value of the quadlet data field in the request packet of the Quadlet Read Request subaction in FIG. 4B. After storing in its arg_register as shown, it searches whether a channel for transmitting isochronous data is available.

In other words, the first node (s) to transmit isochronous data is used for whether there is an unused channel, and the node (s) that were transmitting isochronous data before the bus reset occurred are assigned and used before the reset occurs. Search for available channels.

If the search result channel is available, Node A (or Node B (Node_B)) sets only the corresponding bit of the channel to be used as "1" ("0" in both channels) and sets all remaining bits to "." Set to 0 "(" 1 "for channel transfer), store in data_register as shown in FIG. 4C, write to data_value field of CH_alloc Lock Request packet, and then assign channel lock request subaction. The channel H is requested to the node H by using (Ch_alloc Lock Request Subaction) (in the case of channel transfer, the channel transfer lock request subaction is used).

Then, the node H receiving the Ch_alloc Lock Request packet records the data_register in its data_register and stores the value (AND) of its current CAR in its compare_register (OR in OR). A value), and an exclusive OR of old_value and data_value are stored in new_data_register (OR is ORed with the negated value of old_value and data_value in the channel transfer).

Next, node H records its compare_register value in the compare_value field of the Ch_alloc Lock Response packet and the value of its current CAR in the old_value field and sends it to node A. Since the value of compare_register is equal to the value of data_register, the value of new_data_register is set. The value of the CAR is changed and if it is not the same, the value of the CAR is not changed.

Accordingly, node A stores the compare_value field value of the Ch_alloc Lock Response packet transmitted from the node H in its compare_register and the old_value field value in its arg_register, and then searches whether the rcode of the Ch_alloc Lock Response packet is resp_complete and resp_complete. If it compares the value of its compare_register with the value of data_register, if it is equal, it recognizes that the channel allocation is successful. If it is not resp_complete or if the value of compare_register and the value of data_register are not equal, Ch_alloc Lock is performed using the value recorded in arg-register. Retry the request subaction.

Meanwhile, a quadlet for requesting channel allocation to node H, which is an isochronous resource manager and a root node, through node E, node C, and node F to transmit isochronous data from node A and node B, respectively. When the Quadlet Read Response subaction of the Read Transaction is performed as shown in FIG. 3B, Node H has a higher priority because Node A is closer to the root node than Node B, so the Quadlet Read corresponding to the Quadlet Read Response subaction of Node A is higher. Execute the request subaction.

That is, Node H, which receives the Quadlet Read Response subaction from Node A, performs a Quadlet Read Request subaction in response to this and informs Node A of its current CAR status.

After receiving the Quadlet Read Response subaction from the Node B, Node H performs a Quadlet Read Request subaction corresponding to the Quadlet Read Response subaction and informs Node B of the same CAR status as the CAR status informed to Node A.

Accordingly, the Node A receiving the Quadlet Read Request subaction sends the arg_value field value of the quadlet data field in the request packet of the Quadlet Read Request subaction to its arg_register as shown in FIG. 4B. After storing, it searches whether a channel for transmitting isochronous data is available.

In other words, the first node (s) to transmit isochronous data is used for whether there is an unused channel, and the node (s) that were transmitting isochronous data before the bus reset occurred are assigned and used before the reset occurs. Search for available channels.

If the search result channel is available, node A sets only the corresponding bit of the channel to be used as "1", and sets all remaining bits to "0" and stores the data in the data_register as shown in FIG. After recording in the data_value field of the Ch_alloc Lock Request packet, the channel H is requested to the node H using a Ch_alloc Lock Request Subaction.

Similarly, if the search result channel is available, the Node B sets only the corresponding bit of the channel to be used as "1", and sets all other bits to "0" and stores it in data_register as shown in FIG. 4C. After recording in the data_value field of the Ch_alloc Lock Request packet, the channel H is requested to the node H using a Ch_alloc Lock Request Subaction.

Then, after receiving the Ch_alloc Lock Request packet from the node A, the node H writes to its data_register and stores the current (old_value) and AND of its current CAR in its compare_register, and stores old_value and data_value. Stores an exclusive OR in new_data_register.

Next, node H records its compare_register value in the compare_value field of the Ch_alloc Lock Response packet and the value of its current CAR in the old_value field and sends it to node A. Since the value of compare_register is equal to the value of data_register, the value of new_data_register is set. The value of the CAR is changed and if it is not the same, the value of the CAR is not changed.

In addition, as shown in FIG. 3B, the node H sends a value of the data_value field of the lock request packet transmitted according to the Ch_alloc lock request subaction of the node B, which is transmitted from the node A after the Ch_alloc lock request subaction and is pending. The data_register is stored, the old_value (current CAR value) and the data_value are ANDed and stored in compare_register. The old_value and the data_value are negatively ORed (Exclusive OR) in new_data_register.

Node H then records its compare_register value in the compare_value field of the Ch_alloc Lock Response packet and its current CAR value in the old_value field and sends it to node B. Since the value of compare_register is equal to the value of data_register, the value of new_data_register is set. The value of the CAR is changed and if it is not the same, the value of the CAR is not changed.

Accordingly, node A stores the compare_value field value of the Ch_alloc Lock Response packet transmitted from the node H in its compare_register and the old_value field value in its arg_register, and then searches whether the rcode of the Ch_alloc Lock Response packet is resp_complete and resp_complete. If it compares the value of its compare_register with the value of data_register, if it is equal, it recognizes that the channel allocation is successful. If it is not resp_complete or if the value of compare_register and the value of data_register are not equal, Ch_alloc Lock is performed using the value recorded in arg-register. Retry the request subaction.

Similarly, after the node B stores the compare_value field value of the Ch_alloc Lock Response packet transmitted from the node H in its compare_register and the old_value field value in its arg_register, the node B searches whether the rcode of the Ch_alloc lock response packet is resp_complete and resp_complete. If it compares its own value of compare_register with data_register, it recognizes that the channel allocation is successful. If it is not resp_complete or if compare_register and data_register are not equal, Ch_alloc Lock Request using the value recorded in arg-register Retry the subaction.

Meanwhile, in the case of channel deallocation, only the operation of changing the values of the registers shown in FIGS. 4A to 4F is different, and the basic lock transition concept is the same.

As described above, the bus control apparatus and method of the digital interface according to the present invention have the following effects.

First, at least two isochronous capacitive nodes on the IEEE 1394 serial bus can reduce the retry that occurs when trying to allocate different channels at the same time by using a lock transaction. By preventing occurrences, the performance of the digital interface can be improved.

Second, in the case of a lock transaction for deallocation of an allocated channel after isochronous data transmission, a CAR value of a node that is an isochronous resource manager by another node (s) allocated the channel. If this change does not change only the assigned channel, the channel can be transferred.

Third, a bus reset has occurred due to the addition or removal of an arbitrary node, so that nodes that were transmitting isochronous data before the bus reset continued to transmit isochronous data after the bus reset. Even if it is necessary to reassign a channel that had been allocated before bus reset within a short time, unnecessary lock transaction can be reduced so that the channel can be reallocated within a predetermined time.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (4)

New lock transaction (Extended_code field) of lock request packet and lock response packet during lock transaction with isochronous resource manager Setting); The isochronous resource manager when the lock transaction executed by another node does not change the value of a channel for which allocation or transfer is requested by the other node when the set lock transaction is performed. The bus control method of the digital interface, characterized in that it comprises a step of always assigning and transferring a channel from). The method of claim 1, The new lock transaction is a lock transaction using a channel allocation function (ch_alloc function) when a channel allocation request is requested and a channel transfer function (ch_dealloc function) when a channel assignment request is requested. . The method of claim 1, In the step of allocating and transferring the channel, a lock transaction using the channel allocation function (ch_alloc function) is a value of a channel available register of the isochronous resource manager. The value of the desired channel is set to "1", the rest is set to "0", and the data is stored in the data register (data_register), and then the channel allocation lock request (Ch_alloc Lock Request subaction) is performed to the isochronous resource manager. Bus control method of a digital interface, characterized in that the transmission to the (Isochronous Resource Manager). A channel available register (CAR) of an isochronous resource manager (IRM) indicating an allocation state of a current channel; An arg register for storing an arg_value field value of a read response packet and an old_value field value of a lock response packet; A data register that stores a value for changing a CAR value of an IRM node through a data_value field of a lock request packet by setting only bits of a channel required by an arg value recorded in the arg register when a channel allocation request is made. Wow; An IRM receiving the lock request packet includes an old register and an data_value when an allocation request is requested, and a compare register for storing only the same value by comparing the two values when the transfer request is made; When the IRM node that receives the lock request packet has a channel allocation request for the current CAR value and the data_value field value of the lock request packet, an Exclusive_OR value of old_value and data_value is shown in both cities. A bus controller of a digital interface, comprising a new_data register for storing an ORed value.