DMA (Direct Memory Access) controller access implementation method for Loongson blade large-memory address devices

A DMA controller, memory address technology, applied in instruments, electrical digital data processing, etc., can solve problems such as not supporting large memory

Inactive Publication Date: 2012-01-25
SUGON INFORMATION IND
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AI Technical Summary

Problems solved by technology

However, the current Loongson products do not support large memory, so in

Method used

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Embodiment Construction

[0012] Loongson CPU is a 32-bit CPU. If the address space exceeds 32 bits, then Loongson CPU cannot support it. The present invention supports up to 64-bit address space by adding a management control module, an address resolution module, an address translation module and a mapping module.

[0013] The management control module is responsible for dividing the address space higher than 32 bits. After the division is completed, the management control module applies for a block address range of the same size in the memory. When there is a DMA application, it is first handed over to the address resolution module for judgment. If the address is in the 32-bit address space, traditional DMA data transmission is performed; when the address space is larger than the 32-bit address, the address translation module is used for address translation.

[0014] The address conversion module calculates the number of bits to be shifted according to the pre-applied block size, and performs the shif...

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Abstract

The invention provides a DMA controller access implementation method for Loongson blade large-memory address devices. A management control module applies for a 256M address space in a memory; when a DMA controller and an address space lower than 32 bits carry out data transmission, data are transmitted according to the conventional DMA transmission mode; when the DMA controller and an address space higher than 32 bits carry out data transmission, the DMA controller sends an access address to an address-parsing module, the address-parsing module parses and then sends the address to an address conversion module, the address conversion module converts the address, and a mapping module carries out memory mapping according to the address converted by the address conversion module to map the address higher than 32 bits into the memory for which the management control module applies in advance. The method effectively solves the problem that a 32-bit Loongson CPU (central processing unit) cannot support memories exceeding the 32-bit address, and thereby the Loongson CPU can use a 64-bit address space at most.

Description

technical field [0001] The present invention relates to a method for supporting a large memory of a Loongson blade, specifically, a method for realizing access to a DMA controller of a Loongson blade large memory address device Background technique [0002] At present, the device address is generally 32 bits. If the device is in the case of DMA data transmission with the memory, the device will not be recognized when the memory address is greater than 32 bits. So some methods are needed to solve this problem. The Linux kernel version requires a pass The data cache to the storage device must be placed in the low-end memory area of ​​the physical RAM, even if the application can use both high-end memory and low-end memory at the same time. In this way, I / O requests from the data cache in the low-end memory area can directly perform memory access operations. However, when the application issues an I / O request that includes a data cache located in high memory, the kernel will f...

Claims

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Application Information

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IPC IPC(8): G06F13/28
Inventor 邵宗有刘新春杨晓君李丰旺郑臣明李永成尹宁宁
Owner SUGON INFORMATION IND
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