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Method for a multitasking DMA controller

IP.com Disclosure Number: IPCOM000011435D
Publication Date: 2003-Feb-19
Document File: 3 page(s) / 98K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a multitasking direct memory access (DMA) controller. Benefits include improved performance and improved power performance.

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Method for a multitasking DMA controller

Disclosed is a method for a multitasking direct memory access (DMA) controller. Benefits include improved performance and improved power performance.

Background

              DMA channels consume power and use register space.

              In some conventional application spaces, such as embedded and communications chipsets, a very large number of DMA channels and application/driver control of the channel (rather than the operating system) are advantageous.

              For a single threaded DMA linked list, command blocks are fetched and executed in a sequential fashion (see Figure 1). The DMA channel is idle during command fetch and while a command block is awaiting execution.

General description

              The disclosed method is a DMA controller that can process multiple independent linked lists using a single hardware channel (see Figure 2). The controller arbitrates the multiple independent linked lists (virtual channels).

              The disclosed method reduces the overall number of hardware channels, saving gate count and power.

              By supporting multiple linked lists, the operating system (OS) can allocate virtual channels to an application/driver while maintaining control over the arbitration time between virtual channels. This technique enables each driver to control/manage its own DMA channel, which appears to the application as a dedicated DMA resource. This technique can also be leveraged within virtual machine environments.

 

              The disclosed method supports practical and affordable DMA implementations for the...