CN109857686A

CN109857686A - A kind of method that DMA data synchronous transfer becomes asynchronous transmission

Info

Publication number: CN109857686A
Application number: CN201910230653.1A
Authority: CN
Inventors: 张志运
Original assignee: BEIJING SIMPLIGHT NANOELECTRONICS Co Ltd
Current assignee: BEIJING SIMPLIGHT NANOELECTRONICS Co Ltd
Priority date: 2019-03-26
Filing date: 2019-03-26
Publication date: 2019-06-07
Anticipated expiration: 2039-03-26
Also published as: CN109857686B

Abstract

The invention discloses a kind of methods that DMA data synchronous transfer becomes asynchronous transmission, S1, set high-priority task for the current data packet of transmission, being allocated resources to described by CPU is currently data packet；S2, the starting DMA transfer corresponding with the current data packet in the transmission process that CPU distributes resource to the current data packet, go to low priority task for the DMA transfer；The cpu resource that S3, release high-priority task occupy, resource needed for distributing the MDA transmission by CPU, completes the DMA transfer；S4, step S1 ~ S3 is repeated, realizes the data transfer operation of next data packet and its corresponding DMA transfer；DMA transfer corresponding with data packet in data transmission procedure and data packet can be transmitted asynchronous transmission by the present invention, improve the efficiency of transmission of data packet, and promote cpu busy percentage.

Description

A kind of method that DMA data synchronous transfer becomes asynchronous transmission

Technical field

The invention belongs to the transmission technique field of DMA (DirectMemory Access, direct memory access) data, tools Body is related to a kind of method of DMA data synchronous transfer change asynchronous transmission.

Background technique

DMA data transfer refers to that data-moving is gone to complete by other individually hardware system independently of CPU, does not have to CPU and joins With data-moving；In the prior art, when data-moving is completed, general data moves hardware generation interrupt event and removes notice CPU, Data-moving has been completed.But when encountering some special circumstances, such as when moving data is less, or interrupts expense and generate Overhead it is excessive when, although using CPU is synchronous wait DMA data transfer to terminate by the way of often more efficiently；But together The mode that step waits needs to occupy CPU, to the phenomenon that cpu resource waste occur, and data transmission efficiency is relatively low.

Summary of the invention

It is existing to solve the purpose of the present invention is to propose to a kind of method that DMA data synchronous transfer becomes asynchronous transmission The wasting of resources phenomenon and corresponding data transmission efficiency occurred during DMA data synchronous transfer due to occupying cpu resource Low problem, specific technical solution are as follows:

A kind of method that DMA data synchronous transfer becomes asynchronous transmission, the method includes the steps:

S1, high-priority task is set by the current data packet of transmission, being allocated resources to described by CPU is currently data packet；

S2, starting is corresponding with the current data packet in the transmission process that CPU distributes resource to the current data packet The DMA transfer is gone to low priority task by DMA transfer；

The cpu resource that S3, release high-priority task occupy distributes the MDA transmission required resource, described in completion by CPU DMA transfer；

S4, repeat step S1 ~ S3, realize the data packet of transmission in need and its corresponding DMA transfer data transfer operation.

The method that DMA data synchronous transfer of the invention becomes asynchronous transmission, in data transmission procedure, by data packet portions It is set as high-priority task, DMA transfer corresponding with data packet is set as low priority task, first by CPU to high preferential The allocation of packets resource of grade task is transmitted, and starts DMA transfer simultaneously, after current data packet is transmitted, release Corresponding cpu resource, and the resource for distributing specified size to DMA transfer carries out DMA data transfer realizes that data packet and DMA's is different Step transmission；Compared with prior art, the present invention can by data packet and DMA asynchronous transmission, improving data transmission efficiency and CPU's Utilization rate.

Detailed description of the invention

Fig. 1 is the flow chart signal for the method that DMA data synchronous transfer described in the embodiment of the present invention becomes asynchronous transmission；

Fig. 2 is the cpu resource become in the embodiment of the present invention with the DMA data synchronous transfer during the method for asynchronous transmission Switching diagram meaning.

Specific embodiment

In order to enable those skilled in the art to better understand the solution of the present invention, below in conjunction in the embodiment of the present invention Attached drawing, technical scheme in the embodiment of the invention is clearly and completely described.

In embodiments of the present invention, a kind of method of DMA data synchronous transfer change asynchronous transmission is provided, specifically, side Method comprises the following steps that

Step 1: setting high-priority task for the current data packet of transmission, being allocated resources to described by CPU is currently data Packet.

Step 2: starting and the current data in the transmission process that CPU distributes resource to the current data packet Corresponding DMA transfer is wrapped, the DMA transfer is gone into low priority task.Step 3: what release high-priority task occupied Cpu resource, resource needed for distributing the MDA transmission by CPU, completes the DMA transfer.

Step 4: repeat the above steps one, step 2 and step 3, realize transmission in need data packet and its correspondence DMA transfer data transfer operation.

Refering to fig. 1, in combination with corresponding source code, it is assumed that need to transmit n data packet altogether, n data packet is respectively provided with For high-priority task, and low priority task is set by the corresponding DMA transfer of each data packet；In conjunction with Fig. 2, then when first Data packet reaches, and first distributes resource to high-priority task by CPU, i.e., first handles the first data packet to the n-th data packet, and is locating When managing each data packet, the corresponding DMA transfer of data packet is started and waits being given to low priority of the task；In low priority Task start and when wait the corresponding DMA transfer of the first data packet to terminate, at this time the second new data packet, which reaches, needs It handles, likewise, the second data packet is high-priority task；When having handled the second data packet, CPU release, low priority DMA transfer task obtain scheduling and execute, at this time the DMA transfer of the first data packet or terminated to transmit, in actual operation, There is no occupancy or less occupancy CPU time, and the DMA transfer for waiting the first data packet to be gone to terminate for the task of low priority；To Realizing the transmission of synchronous DMA data from process becomes asynchronous transmission, substantially increases data transmission efficiency and cpu busy percentage.

The following are the processes of data processing and DMA transfer when handling by the method for the invention each data packet to describe Source code, wherein Task 1 indicates that the description source code of data processing, Task 2 indicate the description source code of DMA transfer, specifically Are as follows:

1 high-priority task code exemplary flow of Task

void TASK1_main(void)

{

EVTS reqEvts = Task1_Init();//TASK initialization

While(1)

{

EVTS evts = Event_Obtain(TASK1_ID, reqEvts, TRUE);// obtain all task signal

evts &= reqEvts;// filter oneself task signal

task1 data procedure;

configure TASK2 parameters;

Send_signal(TASK2_ID, (void **)&pCmd);// TASK2 is sent a signal to, start TASK2

}

Task2 low priority task code exemplary flow

void TASK2_main(void)

{

EVTS reqEvts = Task2_Init();//TASK initialization

While(1)

{

EVTS evts = Event_Obtain(TASK2_ID, reqEvts, TRUE);// obtain all task signal

evts &= reqEvts;// filter oneself task signal

configure DMA parameters, start DMA transfer.

while(1) //wait DMA transmission finished

{

If(DMA transfer finished)

break;

}

Send_signal(TASKn_ID, (void **)&pCmd);// other task is sent a signal to, continue subsequent processing

}

In embodiment, if multiple data packets need to be transmitted, each data packet treatment process includes Task 1 and Task 2 two Process described by source code.

The foregoing is merely a prefered embodiment of the invention, is not intended to limit the scope of the patents of the invention, although referring to aforementioned reality Applying example, invention is explained in detail, for a person skilled in the art, still can be to aforementioned each specific Technical solution documented by embodiment is modified, or carries out equivalence replacement to part of technical characteristic.All utilizations The equivalent structure that description of the invention and accompanying drawing content are done directly or indirectly is used in other related technical areas, together Reason is within the invention patent protection scope.

Claims

1. a kind of method that DMA data synchronous transfer becomes asynchronous transmission, which is characterized in that the method includes the steps: