KR100653463B1 - Priority decision method of direct memory access controller - Google Patents

Abstract

The present invention provides a method for determining the priority of a direct memory access controller that can adjust the priority of a specific module according to a user's request while adjusting the priority by applying the temporal constraint degree of each functional module as a weight. In the method of determining the priority of the direct memory access controller according to the present invention, the relative value of the temporal constraint degree of each module is set to the initial value of the weighting parameter for a plurality of channels connected to each module, and then the data input / output of the multiple channels is requested. While comparing the size of the weighting parameters and performing data input / output of each channel for each priority, the weighting parameters for each channel are adjusted so that the temporal constraint strength of the channel on which data input / output has been performed is weakened every time data input / output is performed. When a reconciliation request occurs, the request channel has the highest priority That is to adjust the weighting parameters of a technical aspect that.

Direct memory access (DMA) controller, weighting parameters, time constraints, user requirements, priorities,

Description

Priority decision method of direct memory access controller

1 is a functional block diagram illustrating a direct memory access controller to which the present invention is applied.

2 is a flowchart showing a priority determining method according to the present invention.

3 is a diagram showing an embodiment of a method for determining priority of the present invention.

4 is a table showing a change in weighting parameters according to the embodiment of FIG. 3.

The present invention relates to a priority determination method of a direct memory access controller that can adjust the priority of a specific module according to a user's request while adjusting the priority by applying the temporal constraint degree of each functional module as a weight.

Recently, a system on a chip (SoC) method of integrating various functions into a single chip is widely used as a system implementation method. Since these SoCs contain various functional modules on a single chip, the processor must be able to effectively control data input and output with various functional modules. In particular, the time characteristics of each functional module are understood so that the correct data can be obtained within a predetermined time. It should be able to input and output.

When the processor is responsible for data input / output control for a plurality of modules, the burden on the processor is increased and effective control is not possible. In this regard, a direct memory access controller (hereinafter referred to as a DMA controller) capable of processing data input / output between a memory and a plurality of functional modules, between a memory and a memory, or between different functional modules in a short time is applied. In this way, it is possible to reduce the burden on the processor while promoting efficient data input and output.

In implementing such a DMA controller, the most important factor is the priority determination method. Priority determination method refers to a method of determining data transmission order between modules according to a certain criterion when n different modules try to transmit data. This priority should be determined in consideration of the temporal characteristics of each module, the size of transmission data, and the user's application.

Generally known prioritization methods include fixed prioritization methods and round-robin methods, among which fixed prioritization methods determine priorities of n functional modules at system initialization. As a result, it is easy to implement, but the priority determined once is not changed. Therefore, when data input / output of a high priority function module is continuously generated, data of the lower priority function module is accumulated and accumulated. Failure to do so may occur.

On the other hand, the round robin method determines the priority at system initialization. Whenever data input / output is performed, the round robin method changes the priority of the module that performs the data input / output to the lowest level, so that even a function module having a low priority may have some degree. To have the opportunity of data I / O. This method is based on the fact that a module that has performed input / output of data once has a certain amount of time until the next input / output of data occurs, which enables efficient input / output control compared to the fixed priority method. However, this method has a problem that a function module that has performed data I / O once falls to the lowest level even for a module having the highest priority, so that performance of data I / O requiring real time processing may be delayed.

Accordingly, Korean Patent Publication No. 2004-42321 (published May 20, 2004) proposed a priority determination method using weight parameters to enable efficient data input / output control while minimizing time constraints between functional modules. .

The method is based on the round robin method, and assigns weighting parameters corresponding to time constraints to each module, and determines the highest priority channel according to the size of the weighting parameters given when requesting data input / output from a plurality of modules. I / O is performed. After performing data input, the weight parameters assigned to other function modules are changed.

The weighted method of the proposed round robin method enables data input and output without breaking the time constraints of each functional module in a short time. However, the weight is a numerical value of only the degree of time constraint of each module as a relative value, and there is a problem that a user's request cannot be applied when controlling data input / output.

The present invention has been proposed to improve the above-mentioned conventional problems, and its purpose is to adjust the priority of a specific module according to a user's request while adjusting the priority by applying a temporal constraint degree of each functional module as a weight. It is to provide a method for determining the priority of a direct memory access controller.

As a constituent means for achieving the above object, the method of determining the priority of the direct memory access controller according to the present invention,

An initializing step of giving a plurality of channels connected to each module a relative value of a time constraint degree of each module as an initial value of a weighting parameter;

A determination step of determining whether a channel for requesting data input / output is one channel or two or more channels when data input / output requests are made in the plurality of channels;

If there are two or more data I / O request channels, the weight of the weighting parameter of the channel where the I / O request occurs is determined to determine the highest priority channel, the determined highest priority channel is selected to perform data I / O, and then the time of the channel that performed data I / O. Adjusting a weighting parameter for each channel so that the constraint strength is weakened;

A second adjustment step of adjusting the most parameter for each channel so that the temporal constraint strength of the channel on which the data I / O is performed is weakened after selecting the channel where the I / O request has occurred and performing data I / O when there is one data I / O request channel; And

A user adjustment step of checking whether a user priority adjustment request occurs and adjusting the weighting parameter such that the request channel becomes the highest priority when a user priority adjustment request occurs,
In the initializing step, the weighting parameter is set in inverse proportion to the temporal constraint intensity.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic configuration diagram of a direct memory access controller to which a method for determining priority of the present invention is applied.

Referring to FIG. 1, the direct memory access controller to which the present invention is applied determines the priority between the input / output channel and the data operation unit 110 for inputting data such as weight parameters and user requests, and the weight parameters. The memory 130 for controlling data input and output, and a weight parameter table for managing the weight parameters corresponding to the time limit of each module required for the firmware and control required by the control unit 120 for each channel is stored in the memory 130 And an input / output request determination unit 140 for determining whether there is a data input / output request for each channel, and if there are any input / output requests, and the data input / output request determined by the input / output request determination unit 140. Among the channels, the channel having the highest priority is determined by referring to the weight parameter table stored in the memory 130. The first input channel determination unit 150, the data input and output processing unit 160 for performing data input and output of the channel of the highest priority determined by the first channel determination unit 150 under the control of the control unit 120, and the control unit According to the control of the 120 and the weight parameter adjustment unit 170 for adjusting the weight parameters of each input and output channel after performing the data input and output, and the user request, the data communication is performed through the data input and output processing unit 160 is connected to each module It includes a channel unit 180 consisting of a plurality of channels.

The configuration of the direct memory access controller is an example of a functional block diagram that can properly perform the priority determination method according to the present invention described below.

According to the present invention, in the direct memory access controller, when a plurality of data input / output requests are made, the priority of the direct memory access controller is appropriately determined to enable efficient data input / output control, and FIG. 2 illustrates a method for determining priority according to the present invention. It is a flowchart.

Referring to FIG. 2, in the priority determining method according to the present invention, in the first step S110, a weighting parameter corresponding to a time constraint degree of each module is assigned to each module through the data manipulation unit 110. Initialize the priority of the connected channels CH1 to CHN. At this time, the priority method is to prioritize the channels with the most time constraints. The temporal constraint degree is set as a weighting parameter for each channel, and the weighting parameter for each channel is a relative value for the frequency of input / output operations per channel and the importance of processed data, and an initial value is set by a user. In addition, the weighting parameter is a numerical value of the temporal constraint of each module as a relative value. In one embodiment, an arbitrary module is set as a reference module, and a reference weighting parameter is assigned to the reference module. With respect to time constraints, the relative temporal constraints of other modules can be set by the weighting parameters of each channel. In another embodiment, the module having the lowest temporal constraint is set as the reference module, and the reference weighting parameter is assigned to the channel connected to the reference module, and the channel connected to the other module is relative to the temporal constraint degree of the reference module. You can set the degree of constraint as a weight parameter.

The channel-specific weighting parameters set in this way are stored in the weighting parameter table of the storage means such as the memory 130 of FIG. 1.

Since the prioritization according to the present invention is executed when a data input / output request has occurred substantially, according to the present invention, any channel among the plurality of channels CH1 to CHN connected in the second steps S120 and S130 is used. Check whether the data input / output request has occurred and whether more than one channel has generated the input / output request.

If an I / O request is generated from a single channel, the I / O of data may be performed through the requested channel without determining the priority of each channel. If an I / O request is generated from two channels, the priority between the request channels is required. Should be set.

Therefore, when the number of the required channels is two or more, in the third step (S140 ~ S170), the priority is determined by comparing the weight parameters between each channel with reference to the stored weight parameter table, and the result of the time constraint is After determining the strongest channel as the highest priority channel, data input / output is performed through the determined highest priority channel, and the weighting parameter for each channel is adjusted so that the time constraint of the channel performing the data input / output is reduced.

In addition, in the case where the number of the required channels is one, no separate priority determination is necessary. In the fourth step (S190), data input / output is performed immediately through the request channel, and time constraints of the channel on which the data input / output is performed are performed. Adjust the channel-specific weighting parameters to weaken the accuracy.

The weight parameter adjustment for each channel in the third and fourth steps S140 to S170 and S190 may be performed by reducing the weight parameter of another channel by the weight parameter value of the channel on which data input / output is performed. have. More specifically, since the weight parameter represents the degree of time constraint between modules as a relative value, the lower the number, the higher the priority, and the weight of the channel that performed the data input / output does not perform the data input / output as different as the weight parameter of the channel. By reducing the weighting parameter, the degree of time constraint of the channel on which data input / output is performed is relatively reduced.

According to the prioritization method of the present invention, the weight parameter is adjusted according to the data input / output frequency as described above, and the weight parameter can be forcibly adjusted by the user's request.

That is, in the fifth step (S200 ~ S220), the priority determination method of the present invention checks whether the priority adjustment request of the user occurs, so that when the user priority request occurs, the degree of time constraint of the requested channel becomes the strongest. Change the weighting parameters to adjust the priority. In other words, as the value of the weighting parameter is lower, the temporal constraint becomes stronger. Therefore, the weighting parameter of the channel requested by the user is set to 0, which is the lowest temporal constraint. Accordingly, the priority of the user request channel may be changed to the highest priority. Therefore, when the next data input / output request occurs simultaneously, the data of the user request channel can be input / output first.

The above first to fifth steps are repeatedly performed until the operation is terminated after the initialization of the direct memory access controller, so that the direct memory access controller can efficiently control data input and output through a plurality of channels. It can be properly reflected.

3 and 4, an embodiment of the above-described priority determination method of the present invention will be described.

Referring to FIGS. 3 and 4, the channels connected to the respective functional modules and capable of directly requesting data input / output to the memory access controller are referred to as Ch1, Ch2, and Ch3. As a temporal constraint for each channel, Ch1 is 20 msec. At one time, assume that Ch2 should operate once every 50 msec and Ch3 once every 100 msec.

When the weight parameters of each channel are initialized based on 20 msec of Ch1 having the highest temporal constraint level based on the time constraints of each channel as described above, the weight parameters for each channel are the initial values of the table of FIG. 4. As described above, Ch1 is 1, Ch2 is 2.5, and Ch4 is 5. Therefore, the priority of each channel becomes Ch1> Ch2> Ch in step S310.

In this state, if a data input / output request occurs in ch1, since it is an input / output request for a single channel, by the fourth step (S190) of FIG. 2, data input / output to Ch1 is performed, and at the same time, Ch1 performs data input / output. The weight parameters are reset to their initial values and the weight parameters for the remaining channels Ch2 and Ch3 are adjusted. At this time, since the weighting parameter of Ch1 on which data input / output has been performed is 1, the weighting parameters of Ch2 and Ch3 are decreased by 1, and as shown in FIG. 4, the weighting parameters of Ch2 and Ch3 are changed to 1.5 and 4, respectively (①). At this time, if the reduced weight parameter is a negative value, the current value is maintained or set to 0 without decreasing. When the priority is readjusted according to the weighting parameter changed as above, it becomes Ch1> Ch2> Ch3 (S320).

Subsequently, if a user request for Ch2 occurs, the weighting parameter of the corresponding user requesting channel Ch2 is changed to a value having the strongest temporal constraint strength, that is, 0 (2), and the priority is reset by the changed weighting parameter. When listed, the channel priority is Ch2> Ch1> Ch3, where Ch2 is the highest priority and Ch3 is the lowest (S330).

In this state, when input / output requests of Ch1 and Ch2 occur simultaneously, according to the present invention, Ch2 having the highest priority is selected, and data input / output is performed through Ch2. Then, as before, the weighting parameters of Ch2 are reduced to initial values, and the weighting parameters of Ch1 and Ch3 are reduced by the weighting parameters of Ch2, and so on (3). As a result, the weighted parameter changed as shown in the table of FIG. 4 is changed to 0 since Ch1 is negative, and Ch2 is changed to 2.5, which is an initial value, and Ch3 is reduced to 2.5 to 1.5.

When the priority is re-arranged according to the changed weighting parameter, Ch1> Ch3> Ch2, Ch1 becomes the highest priority and Ch2 becomes the lowest (S340).

Subsequently, Ch1 having a simultaneous input / output request with Ch2 is selected, and data input / output is performed through Ch1. Thereafter, as before, the weighting parameter of Ch1 is reduced to an initial value of 1, and Ch2 and Ch3 are reduced by 1, respectively, to 1.5 and 0.5 (4).

When the priority is re-arranged according to the changed weighting parameter, Ch3> Ch1> Ch2 is the highest priority, Ch3, which has never had data input / output, and is then ranked in order of Ch1 and Ch2 according to the time constraints (S350). ).

Meanwhile, in the above description of the present invention, specific embodiments have been described, but the present invention is not limited to the above, and various modifications may be made without departing from the scope of the present invention.

 As described above, when a direct memory access controller is implemented by using the prioritization method of the present invention, in a highly integrated system having multiple I / O paths with high time constraints, data input / output friction between modules can be reduced. By using the temporal constraint as an adjustment parameter, it is possible to determine a more effective priority and to implement a system in which the temporal constraint of each module is minimized. In addition, according to the present invention, by forcibly changing the priority according to the user's request, there is an excellent effect that can enable the operation suitable for the user's application.

Claims (7)

delete delete delete In the prioritization method of the direct memory access controller for controlling data input and output for a plurality of channels connected to a plurality of modules, An initializing step of giving a plurality of channels connected to each module a relative value of a time constraint degree of each module as an initial value of a weighting parameter; A determination step of determining whether a channel for requesting data input / output is one channel or two or more channels when data input / output requests are made in the plurality of channels; If there are two or more data I / O request channels, the priority channel is determined by comparing the weighting parameters of the channel where the I / O request occurs, and after selecting the highest priority channel to perform data I / O, the time constraints of the channel where data I / O is performed A first adjustment step of adjusting the channel-specific weighting parameters so that the strength is weakened; A second adjustment step of adjusting the most parameter for each channel so that the temporal constraint strength of the channel on which the data I / O is performed is weakened after selecting the channel where the I / O request has occurred and performing data I / O when there is one data I / O request channel; And A user adjustment step of checking whether a user priority adjustment request occurs and adjusting the weighting parameter such that the request channel becomes the highest priority when a user priority adjustment request occurs, In the initializing step, the weighting parameter is set in inverse proportion to a temporal constraint strength. The method of claim 4, wherein the first and second adjustment steps are Priority of the direct memory access controller characterized in that the weighting parameters of the channels on which data input / output is performed are reduced to initial values, and the weighting parameters of other channels are reduced by the initial value of the weighting parameters of the channels on which data input / output is performed. How to decide. The method of claim 5, wherein the first and second adjustment step is If the value is negative by subtracting the weighting parameter of the channel on which data input / output is performed from the weighting parameter of each channel, the current value is maintained. The method of claim 4, wherein the user adjustment step And setting the weighting parameter of the channel on which the priority adjustment request by the user is generated to zero.

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