JP2003256358A - Arbiter apparatus and method therefor as well as resource sharing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an arbiter apparatus and method therefor enabling arbitration based on priority, when sharing resources with a plurality of clients. <P>SOLUTION: A request signal from each client is subjected to the arbitration after being masked for a time based on a timer value from a host CPU. If the timer value is extended, it becomes disadvantageous to the arbitration, and becomes advantageous to the arbitration when the timer value is shortened. Consequently, priority in the arbitration can be set according to the timer value given by the host CPU. Also, if an effective arbitration is not performed as a result of the arbitration performed at a first round robin circuit, a grant signal from a second round robin circuit is output. Accordingly, it is prevented that a request remains, as the effective arbitration is not performed, when the arbitration is performed by weighting the request signal on the basis of the priority. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arbiter device and method used to arbitrate access when a plurality of clients share a resource, and a resource sharing system.

[0002]

2. Description of the Related Art When a plurality of clients share a resource, an arbiter is used to arbitrate access from the plurality of clients to the resource.

For example, MPEG (Moving Picture Codin)
g Experts Group) 2 transport stream is input, video packets and audio packets are separated from this transport stream, image processing is performed on the decoded video data, and OSD (On S
An image processing chip that superimposes images is under development.

Such an image processing chip has an MPEG
Transport stream processor for separating 2 TS (Transport Stream) packets, a graphics engine for performing various image processing, a display for generating and superimposing an OSD screen, and enlarging or reducing the screen A processor and the like are arranged. A large amount of memory is required for the processing of these processors, and the memory is shared by the processors.

In such a case, a processor such as a transport stream processor, a graphics engine, or a display processor corresponds to a plurality of clients, and a memory corresponds to one resource.

In such an image processing chip,
Access to one memory from multiple processors may occur simultaneously. The arbiter arbitrates access requests from a plurality of clients for such one resource.

That is, FIG. 11 shows an example of an image processing chip suitable for use in reproducing a digital satellite broadcast. In FIG. 11, the stream processor 101
T from the TS stream of MPEG2 by referring to PID
S packets are separated. Stream processor 10
The video packet separated by 1 is sent to the video decoding processor 102, and the audio packet is sent to the audio decoding processor 103. The information packet is sent to the main processor 104.

The video decode processor 102 uses an MP
Video data compressed by the EG2 method is decoded. The audio decoding processor 103 is AA
Audio data compressed by the C (Advanced Audio Coding) method or the like is decoded.

The graphics engine 105 performs graphics processing based on the graphics data. The display processor 106 performs processing such as OSD screen processing, image enlargement, and deformation. SD
TV (Standard Definition Television) encoder 1
07 performs image size conversion and the like so that the video data sent in various image formats is in the NTSC system, for example. HDTV (High Definition
Television) encoder 108 converts video data sent in various image formats into, for example, NTSC.
The image size is converted so that the system can be used.

A stream processor 101 and a video decoding processor 1 arranged in such an image processing chip.
02, audio decoding processor 103, graphics engine 105, display processor 10
6, SDTV encoder 107, HDTV encoder 1
Each of the 08s requires a large amount of high-speed memory for processing. A memory 110 is provided as a common memory for these processors. The memory 110 is, for example, an SDRAM (Synchronous Dynamic Random).
Access Memory) is used.

In this case, the stream processor 101,
Video decoding processor 102, audio decoding processor 103, graphics engine 105, display processor 106, SDTV encoder 10
7. The HDTV encoder 108 becomes a client,
The memory 110 becomes a common resource. An arbiter 109 is provided for arbitration from each client.

[0012]

As described above, as an arbiter that performs arbitration when a plurality of clients share one resource, conventionally, arbitration is equally performed for each client like the token ring system. A round robin circuit to do is used. In the token ring method, a token is run between each unit that receives a request for each client, and when a request signal comes to each unit, only the unit that has the token can issue a grant signal. .
In the token ring system, since tokens run evenly between units, arbitration is equally done for each client.

However, the priority when each client requests the use of resources cannot be said to be equal.

For example, the image processing chip as described above performs a process requiring a real-time property such as a moving image process, and a process requiring a low real-time property such as a background image process. There is a place. In the moving image processing, if the processing is delayed, the reproduced image is interrupted, which is very conspicuous. On the other hand, the processing of the background image is not so noticeable even if the processing is delayed.

Therefore, it is desired that the arbitration be performed by giving priority to each client, instead of performing the arbitration equally. That is, when there is a request from a client that requires real-time processing such as video processing and a request from a client that does not require real-time processing such as background image processing, video processing It is desirable to preferentially permit the use of resources for requests from clients that require real-time processing.

The priority is not decided for each client. The priority varies depending on various factors such as what kind of processing each client is performing. Therefore, it is desired that the priority can be easily changed by an external operation.

Therefore, it is an object of the present invention to provide an arbiter device and method, and a resource sharing system, which enable arbitration according to priority when a plurality of clients share a resource.

Another object of the present invention is to provide an arbiter device and method which can easily change the priority according to the processing status and mode of each client when a plurality of clients share resources. , To provide a resource sharing system.

[0019]

SUMMARY OF THE INVENTION The present invention arbitrates a request signal generated from each client when a plurality of clients share a resource, and one of the clients is permitted to use the resource. An arbiter device that gives a grant signal to a client, and arbitrates the request signal sent through the request mask means and the request mask means that masks the request signal sent from the client for a time period according to the timer setting value. , An arbiter device having round robin means for outputting a grant signal to one client that permits use of resources among a plurality of clients, and performing arbitration by weighting according to a timer setting value. is there.

The present invention arbitrates a request signal generated from each client when a resource is shared by a plurality of clients, and a grant signal is sent to one client who is permitted to use the resource among the plurality of clients. An arbiter device for giving arbitration so as to arbitrate request signals from clients by weighting according to priority and arbitrating request signals from clients, and arbitrating so that request signals from all clients are arbitrated. A second arbitration means, a selector means for switching the grant signal from the first arbitration means, and a grant signal from the second arbitration means are provided, and the selector means performs the arbitration by the first arbitration means. If effective arbitration is performed, the grant signal from the first arbitration means is selected and output, and the arbitration is performed by the first arbitration means. To be done result valid arbitration is arbiter apparatus that grant signal selects and outputs from the second arbitration unit.

The present invention arbitrates a request signal generated from each client when a resource is shared by a plurality of clients, and a grant signal is sent to one client who is permitted to use the resource among the plurality of clients. Is an arbiter method for giving a request, masking a request signal sent from a client for a time period according to a timer setting value, arbitrating the masked request signal, and permitting use of resources among a plurality of clients 1 Output grant signal to one client,
This is an arbiter method in which arbitration is performed by weighting according to the timer set value.

The present invention arbitrates a request signal generated from each client when a plurality of clients share a resource, and grants a grant signal to one client who is permitted to use the resource among the plurality of clients. The first arbitration for arbitrating the request signal from the client with weighting according to the priority, and if the effective arbitration is performed as a result of the first arbitration, The grant signal generated as a result of arbitration is output, and if effective arbitration is not performed as a result of the first arbitration, the second arbitration is performed so that request signals from all clients are arbitrated without fail. This is an arbiter method for outputting the grant signal generated as the second arbitration result.

The present invention arbitrates a plurality of clients, a resource shared by the plurality of clients, and a request signal generated from the plurality of clients, and a single resource is permitted to be used among the plurality of clients. It consists of an arbiter that gives a grant signal to the client, and the arbiter sends a request signal through the request mask means for masking the request signal sent from the client for a time period according to the timer setting value. A resource that arbitrates and includes a round-robin unit that outputs a grant signal to one client that permits the use of resources among a plurality of clients, and performs arbitration by weighting according to a timer setting value. It is a shared system.

The present invention arbitrates a plurality of clients, a resource shared by the plurality of clients, and a request signal generated from the plurality of clients, and a single resource is permitted to be used among the plurality of clients. It consists of an arbiter that gives a grant signal to the client, and the arbiter must be provided with the first arbitration means for arbitrating the request signal from the client by weighting it according to the priority and the request signal from all the clients. A second arbitration means for performing arbitration so as to be arbitrated; a selector means for switching between a grant signal from the first arbitration means and a grant signal from the second arbitration means; If effective arbitration is performed as a result of the arbitration performed by the arbitration means of 1, the grant signal from the first arbitration means is selected. Force and, if valid result of the arbitration by the first arbitration unit arbitrating is performed, a resource sharing system so as to select and output a grant signal from the second arbitration unit.

The request signal from each client is
Arbitration is performed after the time is masked according to the timer value. As a result, it is possible to perform arbitration with weighting according to the priority.

That is, according to the present invention, the request signal is masked for the timer value after the grant signal is sent. If the timer value is lengthened, the time during which the request signal is masked becomes long, which is disadvantageous for arbitration, and if the timer value is shortened, it is advantageous for arbitration. Therefore, the priority in arbitration can be set by the timer value given from the host CPU.

In the present invention, the timer value is set by the host CPU. Therefore, it is possible to make appropriate changes according to the state of each client, the setting mode, and the like.

Further, according to the present invention, the first round robin circuit for arbitrating the requests from the clients by weighting according to the priority, and the arbitration so that the requests from all the clients are arbitrated without fail. Do the second
The round-robin circuit is provided and the grant signal from the second round-robin circuit is output if effective arbitration is not performed as a result of the arbitration performed by the first round-robin circuit. As a result, when arbitration is performed with weighting according to priority, effective arbitration is not performed and requests can be prevented from remaining.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention.

In FIG. 1, a resource 11 and a plurality of clients 12A, 12B, 12C, ...
Are connected via a plurality of clients 12A,
12B, 12C, ... Can share one resource 11 via the bus 13. An arbiter 14 is provided so that access conflict does not occur when one resource 11 is shared by a plurality of clients 12A, 12B, 12C, ....

For example, in the case of an image processing chip, a stream processor, a video decoding processor, an audio decoding processor, a graphics engine, a display processor, an SDTV encoder, an HDTV.
The encoder and the like are clients 12A, 12B, 12C,
..., and the memory shared by these processors is the resource 11.

Each client 12A, 12B, 12C,
Send request signals req_a, req_b, req_c, ... To the arbiter 14 when requesting the use of the resource 11. The arbiter 14 includes clients 12A, 12B, 1
Request signals from 2C, ... req_a, req_b, req_c,
... is received, and if there are requests from multiple clients, the request is arbitrated and the client 1
One of the 2A, 12B, 12C, ...
Send gnt_a, gnt_b, gnt_c, ... Client 12
Of A, 12B, 12C, ... Grant signals gnt_a, g
Only the client that has received nt_b, gnt_c, ... Has the right to use the resource 11, and only that client can access the resource 11.

In the arbiter 14 to which the present invention is applied,
Arbitration can be performed according to the priority. The element that determines the priority is specifically the host CPU (Central
Timer values timer_a, timer_b, timer_c, ..., Which are sent from the Processing Unit) 15 to the arbiter 14.

Timer values timer_a, timer_b, timer_c, ...
Thus, the mask period of the request signal is set. During the mask period, the request signal is stopped. Therefore, the smaller the timer values timer_a, timer_b, timer_c, ... Are set, the shorter the period during which the request signal is masked and the higher the priority.

FIG. 2 shows the configuration of the arbiter 14 shown in FIG. The arbiter 14 has the function of masking the request signal according to the priority, as described above. The arbiter 14 includes a request mask circuit 21 and a round robin circuit 22. The request mask circuit 21 includes 1-bit mask circuits 23A and 2A.
3B, 23C, ... Each 1-bit mask circuit 23
A, 23B, 23C, ..., As described later, the round robin circuit 52 supplies the grant signals gnt_a, gnt_b, gn.
After t_c, ... is returned, the timer values timer_a, timer_b, t
Request signals req_a, req_b, re only during imer_c, ...
It operates to mask q_c, ....

In FIG. 2, input terminals 24A, 24B,
24C, ..., Each client 12A, 1 in FIG.
Request signals req_a, req_b from 2B, 12C, ...
req_c, ... is supplied. This request signal req_a, re
q_b, req_c, ... Are request mask circuits 2 respectively.
It is supplied to the 1-bit mask circuits 23A, 23B, 23C ,.

The input terminals 25A, 25B, 25C,
..., the timer values timer_a, timer_b from the CPU 15,
timer_c, ... Is supplied. This timer value timer_a, time
r_b, timer_c, ... Are 1-bit mask circuits 23A, 23B, 23C, ... Of the request mask circuit 21, respectively.
Is supplied to.

Further, the grant signals gnt_a, gnt_b, gnt_c, ... Returned from the round robin circuit 52 are supplied to the 1-bit mask circuits 23A, 23B, 23C ,.

Request signals req_a, req_b, req_c, ... From the input terminals 24A, 24B, 24C, ... Are supplied to the round robin circuit 22 via the 1-bit mask circuits 23A, 23B, 23C ,. The 1-bit mask circuits 23A, 23B, 23C, ...
Request signals req_a, r from A, 24B, 24C, ...
eq_b, req_c, ... are the grant signals gnt_a, gnt_b, gnt_
After c, ... is returned, timer values timer_a, timer_b, tim
Masked only during er_c, ...

The round robin circuit 22 arbitrates a plurality of request signals req_a, req_b, req_c, .... As the round robin circuit 22, for example, a token ring type circuit can be used.

FIG. 3 is a block diagram of the token-ring type round robin circuit 22. As shown in FIG.
The token ring type round robin circuit 22 includes units 41A, 41B, 41 corresponding to respective clients.
C, ... Are provided.

Tokens run between the units 41A, 41B, 41C, .... Only the units 41A, 41B, 41C, ... that have tokens, grant signal
Can issue gnt_a, gnt_b, gnt_c, ...

Each unit 41A, 41B, 41C, ...
Will pass the token to the next unit if there is no request. The tokens are units 41A, 41
B, 41C, ... are sent in that order, and when the last unit 41E is reached, they are returned to the first unit 41A. Therefore, there is a token in any of the units 41A to 41E. Request signal from each client req_
a, req_b, req_c, ... Are sent to each of the units 41A to 41E. Of the units 41A to 41E to which the request signals req_a, req_b, req_c, ... Are sent, only the unit having the token is the grant signal gnt_a, gnt_.
b, gnt_c, ... Can be issued. In this way, each request is arbitrated.

In FIG. 2, when the arbitration is performed, the round robin circuit 22 sends grant signals gnt_a, gnt_b, gn to the clients permitted to use the resources.
tc, ... is output. This grant signal gnt_a, gnt_b,
The gntc, ... Are output from the output terminals 26A, 26B, 26C, ... And are also supplied to the 1-bit mask circuits 23A, 23B, 23C ,.

The grant signals gnt_a, gnt_b, gnt_c, ... From the output terminals 26A, 26B, 26C, ... Are supplied to the clients 12A, 12B, 12C ,. Each client 12A, 12B, 12
Of the C, ..., The usage right of the resource 11 is passed to the client to which the grant signals gnt_a, gnt_b, gntc ,.

Request mask circuit 21 in FIG.
Consists of 1-bit mask circuits 23A, 23B, 23C, .... Each 1-bit mask circuit 23A, 23B, 23
C, ... Are the grant signals gn from the round robin circuit 52.
After t_a, gnt_b, gnt_c, ... are returned, the timer value timer
Request signal re only during _a, timer_b, timer_c, ...
It operates so as to mask q_a, req_b, req_c, .... Such 1-bit mask circuits 23A, 23
B, 23C, ... Can be configured as shown in FIG.

In FIG. 4, the timer value is input to the input terminal 31.
A timer (corresponding to timer values timer_a, timer_b, timer_c, ...) Is supplied. The timer value timer is supplied from the input terminals 25A, 25B, 25C, ... In FIG. The timer value timer from the input terminal 31 is supplied to the counter 32.

A request signal req (corresponding to request signals req_b, req_c, req3, ...) Is supplied to the input terminal 33. The request signal req is supplied from the input terminals 24A, 24B, 24C, ... In FIG. The request signal req from the input terminal 33 is supplied to one input terminal of the AND gate 34.

A grant signal gnt (corresponding to the grant signals gnt_a, gnt_b, gnt_c, ...) Is supplied to the input terminal 35. When the round robin circuit 22 in FIG. 2 performs arbitration, the grant signal gnt is returned to the client who is permitted to use the resource. The grant signal gnt from the input terminal 35 is supplied as a reset signal to the counter 32 and also to the set input of the SR (set / reset) flip-flop 36.

The SR flip-flop 36 has an input terminal 3
It is set by the grant signal gnt from 5 and becomes H (high) level. Then, the counter 32 displays the timer value ti.
When it becomes mer, it is reset by the output signal of the counter 32 and becomes L (low) level.

The counter 32 is reset when the grant signal gnt is supplied to the input terminal 35, and is incremented by the clock clk from the input terminal 38. When the counter 32 is stepped up to the timer value timer from the input terminal 31, the counter 32 supplies a signal to the SR flip-flop 36 and resets the SR flip-flop 36 to the L level. Therefore, the output of the SR flip-flop 36 becomes H level only while the timer value timer from the input terminal 31 is counted after the grant signal gnt is input to the input terminal 35.

While the output of the SR flip-flop 36 is at the L level, the AND gate 34 is open. The AND gate is closed when the output of the SR flip-flop 36 becomes H level while the timer value timer is set after the grant signal gnt is returned. As a result, the request signal req from the input terminal 33 is masked only during the timer value timer after the grant signal gnt is returned to the input terminal 35.

FIG. 5 is a timing diagram representing an operation of the 1-bit mask circuit shown in FIG. In FIG. 5, at time t0, the grant signal gnt from the input terminal 35 (see FIG.
When B) becomes H level, the grant signal gnt resets the counter 32 as shown in FIG. 5D.

Then, at time t1, the grant signal gnt
When (FIG. 5B) falls from the H level to the L level, the SR flip-flop 36 is set and its output becomes the H level, as shown in FIG. 5C.

The output of the SR flip-flop 66 is
The mask signal mask masks the request signal req. As shown in FIG. 5D, the value of the counter 32 changes with time as the clock clk from the input terminal 38 (see FIG.
Steps are taken according to A). At time t2, the counter 32
Is incremented to the timer value timer, the output of the counter 32 resets the SR flip-flop 36 as shown in FIG. 5C, and its output becomes L level.

As described above, the SR flip-flop 36 outputs the timer value t after the grant signal gnt is input.
H level only during imer. The output of the SR flip-flop 36 becomes the mask signal mask. The request signal req from the input terminal 33 is masked by the output (mask signal mask) of the SR flip-flop 36.

For example, as shown in FIG. 6, when the grant signal gnt (FIG. 6A) is supplied at time t10, as shown in FIG. 6B, during the timer value timer (time t11 to time t1.
Only for 3), the output of the SR flip-flop 36 becomes H level. At this time, the request signal as shown in FIG. 6C
If req is supplied to the input terminal 33, this request signal is output from the SR flip-flop 36 (see FIG. 6).
Masked by B), a signal as shown in FIG. 6D is output from the output terminal 37.

That is, at time t12, the request signal re
If q (FIG. 6C) is input, the request signal req input at time t12 is masked by the output of the SR flip-flop 36, and the output terminal 37 (FIG.
Not output immediately from D). At time t13, S
The output of the R flip-flop 36 (FIG. 6B) becomes L level, and the mask is released. Therefore, after the time t13, the request signal req is output to the output terminal 37 (see FIG. 6).
It will be output from D).

As described above, in the 1-bit mask circuits 23A, 23B, 23C, ... In FIGS. 2 and 4, the operation of masking the request signal req only during the timer value timer after the grant signal is returned. Is done.

FIG. 7 shows an arbiter 1 to which the present invention is applied.
FIG. 4 is a timing chart showing an operation when arbitration is performed using No. 4. As described above, when the arbiter 14 to which the present invention is applied is used, the timer values timer_a, timer_b, timer_
By setting c, ..., Arbitration can be performed according to the priority. This timer value timer_a, timer_b, timer_
c, ... Are set to smaller values as the priority is higher.

For example, the client 12A in FIG.
Is most requested, the client 12B requests the next real processing, and the client 12C requests the next real processing. In this case, the timer values timer_a, timer_b, timer_ from the host CPU 15
c is set to have a relationship of (timer_a <timer_b <timer_c). In this way, the client 12A
Has the highest priority, the client 12B has the second highest priority, and the client 12C has the lowest priority.

As shown in FIGS. 7A to 7C, as a result of the previous arbitration, the grant signal gnt_a (FIG. 7A) is returned from the arbiter 14 to the client 12A at time t51, and is sent to the client 12B at time t52. On the other hand, the grant signal gnt_b (FIG. 7B) is returned from the arbiter 14, and the arbiter 14 sends to the client 12C at time t53.
If the grant signal gnt_c (Fig. 7C) is returned from the grant signal gnt_a, as shown in Figs. 7D to 7F.
Is returned from the timer value timer_a, the grant signal gnt
After the _b is returned, the grant signal g
The mask signal mask_a for masking the request signal req_a of the client 12A, the mask signal mask_b for masking the request signal req_b of the client 12B, and the request signal req_c of the client 12C are masked between the timer value timer_c after nt_c is returned. A mask signal mask_c is formed.

Timer values timer_a, timer_b, timer_c, ...
Are set to have a relationship of (timer_a <timer_b <timer_c), and each client 12A, 12B, 1
The request signals req_a, req_b, req_c from 2C are mask signals mas during the timer values timer_a, timer_b, timer_c.
Masked by k_a, mask_b, mask_c.

At time t61, the request signal req_c (FIG. 7I) from the client 12C is input, and then,
Request signal from client 12B at time t62
req_b (Fig. 7H) is input, and finally the request signal req_a (Fig. 7G) from the client 12C at time t63.
Is entered.

When the request signal req_c (FIG. 7I) is input from the client 12C at time t61, the mask signal mask_c (FIG. 7F) is at H level. For this reason,
The request signal req_c from the client 12C sent at time t61 is masked by the mask signal mask_c during the timer value timer_c, and from time t66 after the mask signal mask_c becomes L level as shown in FIG. 7L. Is output.

When the request signal req_b (FIG. 7H) is input from the client 12B at time t62, the mask signal mask_b (FIG. 7E) is at H level. For this reason,
The request signal req_b sent from the client 12C at time t62 is masked by the mask signal mask_b during the timer value timer_b, and from time t64 after the mask signal mask_b becomes L level as shown in FIG. 7K. Is output.

When the request signal req_a (FIG. 7G) is input from the client 12B at time t63, the mask signal mask_a (FIG. 7D) is at L level. For this reason,
As shown in FIG. 7J, the request signal req_a has a time t.
Immediately output from 63.

As shown in FIGS. 7G to 7I, the request signal req_c from the client 12C is first, and the request signal req_b from the client 12B is next. ,
Finally, the request signal req_a from the client 12A
Is.

However, in the arbiter 14, the timer value ti
mer_a, timer_b, timer_c are set. Timer value timer
_a, timer_b, timer_c are (timer_a <timer_b <timer_
By masking the request signal so as to satisfy the relationship of c), the request signal req_a from the client 12A is first output, as shown in FIGS. 7J to 7L.
Next, the request signal req_b from the client 12B
Is output, and finally the request signal req_c from the client 12C is output.

As a result, as shown in FIGS. 7A to 7C,
First, grant signal gnt_a to the client 12A
Is sent, then the grant signal gnt_b is sent to the client 12B, and finally the grant signal gnt_c is sent to the client 12C.

As described above, in the arbiter 14 to which the present invention is applied, the timer value timer_a, ti is transmitted from the host CPU 15.
By setting mer_b, timer_c, ..., Arbitration with priority can be performed. And this timer value
Since the timer_a, timer_b, timer_c, ... Are set by the CPU 15, it is possible to appropriately change the timer_a, timer_b, timer_c, ...

By the way, the arbiter 1 having the configuration shown in FIG.
In 4, the request signal is masked by the timer value according to the priority to arbitrate the request. However, in such a configuration, the request signal may be sent only during the mask period. Even if a request signal is sent from the client, it is possible that effective arbitration remains unperformed.

FIG. 8 shows another example of the arbiter. In this example, the effective arbitration is prevented from being left unperformed.

In FIG. 8, input terminals 54A, 54B,
54C, request signals from req_a, req_b, req_
.. are supplied to the weighted round robin circuit 51 and the round robin circuit 52.

The weighted round robin circuit 51 comprises a request mask circuit for masking a request signal according to a set value and a round robin circuit for arbitrating the request signal via the request mask circuit, and is shown in FIG. It is configured similarly to the arbiter 14.

The weighted round robin circuit 5
From 1, when valid arbitration is performed, a valid signal valid is output. This valid signal valid is supplied to the selector 53 as a select signal.

The round robin circuit 52 performs arbitration for request signals req_a, req_b, req_c, ... From a plurality of clients 12A, 12B, 12C ,. is there. As the round robin circuit 52, the token ring type circuit shown in FIG. 3 can be used.

When the arbitration is performed, the round robin circuit 51 outputs grant signals gnt1_a, gnt1_b, gnt1_c, ... To the clients permitted to use the resources. This grant signal gnt1_a, gnt1_b, gnt1_c,
Is supplied to the selector 53.

When arbitration is performed, the round robin circuit 52 also outputs grant signals gnt2_a, gnt2_b, gnt2_c, ... To the clients whose resources are permitted to be used. This grant signal gnt2_a, gnt2_b, gnt2_c,
Is supplied to the selector 53.

The selector 53 is switched to output the grant signals gnt1_a, gnt_1b, gnt_1c, ... From the weighted round robin circuit 51 when the valid signal valid is output from the weighted round robin circuit 51. When the valid signal valid is not output from the weighted round robin circuit 51, the grant signals gnt2_a, gnt2_b, gnt2_c from the round robin circuit 52, ...
To be output. The output of the selector 53 is output from the output terminals 56A, 56B, 56C, ....

FIG. 9 is a flow chart for explaining the operation of the arbiter shown in FIG. As shown in FIG. 9, the request signals req_a, req_b, req_c from the client,
... is waited for (step S1), and when the request signals req_a, req_b, req_c, ... Are input from the client, first, the weighted round robin circuit 51 performs arbitration (step S2). Then, it is determined whether or not the valid signal valid is output from the weighted round robin circuit 51 (step S3). When the valid signal valid is output, the grant signal generated as a result of the arbitration by the weighted round robin circuit 51 is output (step S4). That is, in this case, the selector 53 selects the grant signals gnt1_a, gnt1_b, gnt1_c, ... From the weighted round robin circuit 51, and the output of the selector 53 is output as the grant signals gnt_a, gnt_b, gnt_c ,. Output from 56B, 56C, ... And returned to the client.

When it is determined in step S3 that the valid signal valid is not output, the round robin circuit 52 performs arbitration (step S5), and the round robin circuit 5
The grant signal generated as a result of the arbitration by 2 is output (step S4). That is, in this case, the selector 53 selects the grant signals gnt2_a, gnt2_b, gnt2_c, ... From the round robin circuit 52, and the selector 5
3 are output from the output terminals 56A, 56B, 56C, ... As grant signals gnt_a, gnt_b, gnt_c ,.
Returned to the client.

As described above, the weighted round robin circuit 51 and the round robin circuit 5 are used in the arbiter shown in FIG.
2 are provided. First, in the weighted round robin circuit 51, the timer values timer_a, timer_b, .timer_c,
... causes weighted arbitration. Then, when the weighted round robin circuit 51 does not perform effective arbitration, the round robin circuit 52 performs final arbitration.

In this example, two stages of arbitration are performed, but it is also possible to perform three or more different stages of arbitration.

In the above example, the token robin circuit is used as the round robin circuit, but the algorithm of the round robin circuit is as follows.
Various types have been proposed, and not only the token ring type but also other types may be used.

For example, as a round-robin circuit, the sub-arbiter previously proposed by the applicant of the present application is arranged in a tree shape, and arbitration is performed in each layer of the tree in order from the lowest layer to the layer above it. , When the tree reaches the top level, a sub-arbiter at the top level can send a grant signal back to the client that sent the request signal through a similar route (Japanese Patent Application No. 2001-104540). ).

FIG. 10 shows such a round robin circuit. In FIG. 10, the sub arbiter 61
Each of A to 61G arbitrates two sub arbiters or clients in the hierarchy below it. In this way, by arranging the two sub arbiters 61A to 61G that arbitrate the two sub arbiters or clients in the hierarchy below it in a tree shape, the sub arbiters 61A to 61G of each hierarchy are arranged.
The two requests are selected in the above, and the requests from the clients 62A to 62H in the lowest layer of the tree structure are finally selected as one by the sub arbiter 61G in the highest layer of this tree structure. It The grant signal is returned to the selected client through the tree structure.

For example, assume that the client 62C issues a request signal req_c to request a resource.

The sub arbiter 61B is the client 62.
The request from C and the request from the client 62D are arbitrated. When the client 62C is selected, the request signal re from the client 62C is sent.
q_c is output from the sub arbiter 61B.

The sub-arbiter 61E is the sub-arbiter 61E.
The request from A and the request from the sub arbiter 61B are arbitrated. When the sub arbiter 61B is selected, the request signal re from the client 62C is sent.
q_c is output from the sub arbiter 61E.

Subarbiter 61 at the top layer of the tree structure
The G arbitrates the request from the sub arbiter 61E and the request from the sub arbiter 61F, and when the sub arbiter 61E is selected, the client 62C is selected.
Request signal req_c from the sub arbiter 61G is output.

Subarbiter 61 at the top layer of the tree structure
When G selects one request, G sends a grant signal gnt to the sub-arbiter 61E on the side that selected the request. This grant signal gnt is received by the sub arbiter 61E.

The sub arbiter 61E is a sub arbiter 61E.
When the grant signal gnt is received from G, the grant signal gnt is sent to the sub arbiter 61B on the side that selected the request. The grant signal gnt is received by the sub arbiter 61B.

The sub-arbiter 61B is the sub-arbiter 61.
When the grant signal gnt is received from E, the grant signal gnt is sent to the client 62C on the side that selected the request.

As described above, the request signal req_c from the client 62C is 2 to 1 in each layer of the tree structure.
Arbitration will continue. As a result of the arbitration in each hierarchy, the grant signal gnt is returned when it reaches the top of the tree structure. This grant signal gnt is returned to the client 62C through a similar tree structure. in this way,
In the round robin circuit shown in FIG. 10, arbitration is performed by a tournament method.

[0096]

According to the present invention, the request signal from each client is arbitrated after being masked for a time corresponding to the timer value. As a result, it is possible to perform arbitration with weighting according to the priority.

That is, in the present invention, the request signal is masked for the timer value after the grant signal is sent. If the timer value is lengthened, the time during which the request signal is masked becomes long, which is disadvantageous for arbitration, and if the timer value is shortened, it is advantageous for arbitration. Therefore, the priority in arbitration can be set by the timer value given from the host CPU.

Further, according to the present invention, the timer value is set from the host CPU. Therefore, it is possible to make appropriate changes according to the state of each client, the setting mode, and the like.

Further, according to the present invention, the first round robin circuit for arbitrating the requests from the clients by weighting according to the priority, and the arbitration so that the requests from all the clients are arbitrated without fail. Do the second
The round-robin circuit is provided and the grant signal from the second round-robin circuit is output if effective arbitration is not performed as a result of the arbitration performed by the first round-robin circuit. As a result, when arbitration is performed with weighting according to the priority, effective arbitration is not performed, and it is possible to prevent requests from remaining.

[Brief description of drawings]

FIG. 1 is a block diagram of an example of a system including a plurality of clients and resources to which the present invention is applied.

FIG. 2 is a block diagram of an example of an arbiter to which the present invention is applied.

FIG. 3 is a block diagram of an example of a round robin circuit.

FIG. 4 is a block diagram of an example of a 1-bit mask circuit.

FIG. 5 is a timing diagram used to explain the operation of the 1-bit mask circuit.

FIG. 6 is a timing chart used for explaining the operation of the 1-bit mask circuit.

FIG. 7 is a timing diagram used for explaining the operation of the arbiter to which the present invention is applied.

FIG. 8 is a block diagram of another example of an arbiter to which the present invention is applied.

FIG. 9 is a flowchart used for explaining another example of the arbiter to which the present invention is applied.

FIG. 10 is a block diagram of another example of a round robin circuit.

FIG. 11 is a block diagram used to describe a system including a plurality of clients and resources.

[Explanation of symbols]

12A, 12B, 12C ... Client, 13 ...
・ Bus, 14 ... Arbiter, 21 ... Request mask circuit, 22 ... Round robin circuit, 23A, 2
3B, 23C ... 1-bit mask circuit, 51 ... Weighted round robin circuit, 52 ... Round robin circuit, 53 ... Selector

Claims (19)

[Claims] 1. A grant signal for arbitrating a request signal generated from each client when a resource is shared by a plurality of clients, and a grant signal for one client permitted to use the resource among the plurality of clients. An arbiter device that provides a request mask means for masking a request signal sent from the client for a time period according to a timer setting value, and an arbitration of the request signal via the request mask means, An arbiter device comprising: a round-robin means for outputting a grant signal to one client that permits the use of resources among the clients, and performing arbitration by weighting according to the timer setting value. 2. The arbiter device according to claim 1, wherein a timer setting value for masking the request signal can be set from the outside. 3. The arbiter device according to claim 1, wherein the time for masking the request signal is set to be within the timer setting value after the grant signal is returned. 4. The round-robin means executes a token between each unit and returns a grant signal only when a request signal comes to a unit having the token to perform arbitration. The arbiter apparatus according to 1. 5. The round robin means arranges sub-arbiters in a tree shape, performs arbitration in each hierarchy of the tree in order from the lowest hierarchy to the hierarchy above it, and reaches the top of the tree. Then, toward the client that sent the request signal from the sub arbiter at the top level,
The arbiter apparatus according to claim 1, wherein arbitration is performed by returning a grant signal through a similar path. 6. A grant signal for one client among the plurality of clients, which arbitrates a request signal generated from each client when the resource is shared by the plurality of clients and which is permitted to use the resource. An arbiter device for providing arbitration, which performs arbitration so that request signals from all clients are arbitrated, and first arbitration means that arbitrates request signals from clients by weighting according to priority. A second arbitration means, a selector means for switching between the grant signal from the first arbitration means and the grant signal from the second arbitration means, wherein the selector means is the first arbitration means. If effective arbitration is performed as a result of the arbitration, the grant signal from the first arbitration means is selected and output, and the first signal is output. If is performed result valid arbitration was arbitrated by the arbitration means, the arbiter apparatus that selects and outputs a grant signal from said second arbitration means. 7. The first arbitration means arbitrates a request mask means for masking a request signal sent from a client for a time period according to a timer set value, and arbitrating the request signal via the request mask means. , Round robin means for outputting a grant signal to one client which permits the use of resources among the plurality of clients, and performs arbitration by weighting according to the timer setting value. Item 7. The arbiter device according to item 6. 8. The second arbitration means performs arbitration by running a token between units and returning a grant signal only when a request signal comes to a unit having the token. The arbiter device according to claim 6. 9. The second arbitration means arranges the sub-arbiters in a tree shape, performs arbitration in each layer of the tree in order from the lowest layer to the layer above it, and arranges the highest layer of the tree. 7. The arbiter device according to claim 6, wherein when the sub-arbiter at the highest level reaches the client, the arbitration device performs arbitration by returning a grant signal through a similar route to the client that sent the request signal. 10. The round-robin means executes a token between each unit and returns a grant signal only when a request signal comes to a unit having the token to perform arbitration. 7. The arbiter device according to 7. 11. The round robin means arranges sub-arbiters in a tree shape, performs arbitration in each hierarchy of the tree in order from the lowest hierarchy to the hierarchy above it, and reaches the top of the tree. The arbiter device according to claim 7, wherein the sub-arbiter of the highest hierarchy returns the grant signal to the client that has sent the request signal through the same route to perform arbitration. 12. A grant signal for arbitrating a request signal generated from each client when a resource is shared by a plurality of clients, and a grant signal for one client permitted to use the resource among the plurality of clients. An arbiter method for giving a request, masking a request signal sent from the client for a time period according to a timer setting value, arbitrating the masked request signal, and using resources among the plurality of clients. An arbiter method in which a grant signal is output to one permitted client and weighting is performed according to the timer setting value to perform arbitration. 13. The arbiter method according to claim 12, wherein a timer set value for masking the request signal can be set from the outside. 14. The time for masking the request signal is
13. The arbiter method according to claim 12, wherein after the grant signal is returned, the time is within the timer setting value. 15. A grant signal for arbitrating a request signal generated from each client when a resource is shared by a plurality of clients, and a grant signal for one client permitted to use the resource among the plurality of clients. In the arbiter method of giving a weight, according to the priority, the first arbitration for arbitrating the request signal from the client is performed, and if effective arbitration is performed as a result of performing the first arbitration,
The grant signal generated as a result of the first arbitration is output, and if effective arbitration is not performed as a result of performing the first arbitration, request signals from all clients are arbitrated without fail. An arbiter method in which arbitration is performed and the grant signal from the second arbitration means is selected and output. 16. The first arbitration masks a request signal sent from the client for a time period according to a timer setting value, arbitrates the masked request signal, and among the plurality of clients. The arbiter method according to claim 15, wherein a grant signal is output to one client that permits use of the resource, and weighting is performed according to the timer setting value to perform arbitration. 17. A client, a resource shared by the plurality of clients, and a request signal generated from the plurality of clients are arbitrated, and the use of the resource is permitted among the plurality of clients. An arbiter that gives a grant signal to one client, the arbiter intervening through the request mask means for masking a request signal sent from the client for a time period according to a timer setting value, and the request mask means. Round robin means for arbitrating the generated request signal and outputting a grant signal to one client that permits the use of the resource among the plurality of clients, and weights it according to the timer setting value. A resource sharing system that performs arbitration. 18. The resource sharing system according to claim 17, further comprising a control device for setting a timer setting value for masking the request signal. 19. Mediating a plurality of clients, a resource shared by the plurality of clients, and a request signal generated from the plurality of clients, and the use of the resources is permitted among the plurality of clients. It consists of an arbiter that gives a grant signal to one client, and the above arbiter assigns a weight according to the priority and arbitrates the request signal from the client, and requests from all clients. A second arbitration means for performing arbitration so that signals are always arbitrated, a selector means for switching between a grant signal from the first arbitration means and a grant signal from the second arbitration means, The selector means, if effective arbitration is performed as a result of the arbitration performed by the first arbitration means, the first means The grant signal from the arbitration unit is selected and output, and if effective arbitration is not performed as a result of the arbitration performed by the first arbitration unit, the grant signal from the second arbitration unit is selected and output. Resource sharing system.