1 <?xml version="1.0" encoding="utf-8"?>

     2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->

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     7     Nokia Corporation - initial contribution.

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    10 <!DOCTYPE concept

    11   PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

    12 <concept id="GUID-C649DB97-F138-4C90-B177-16590F2E3F19-GENID-1-2-1-9-1-6-1-8-1-7-1-3-1" xml:lang="en"><title>DMA Channels</title><shortdesc>Describes how device drivers use DMA channels.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

    13 <p>The DMAC has different DMA channels that can be configured for

    14 different DMA transfers. For some peripherals, such as the Camera

    15 and the Display controller, there can be dedicated DMA channels that

    16 cannot be configured for DMA transfers by other peripherals. However,

    17 drivers generally initialize and open a multi-purpose DMA channel

    18 and use that channel to perform the DMA transfers.</p>

    19 <p>Initialization and opening of DMA channels is done using the interface <xref href="GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37.dita"><apiname>TDmaChannel</apiname></xref>. </p>

    20 <note>This class is designed only for single-thread client access.

    21 When used by multi-threaded clients, synchronization mechanisms should

    22 be provided by the driver. </note>

    23 <p>DMA channels must be opened before use and closed after completion

    24 of DMA operations. </p>

    25 </conbody></concept>