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1 <?xml version="1.0" encoding="utf-8"?> |
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2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. --> |
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3 <!-- This component and the accompanying materials are made available under the terms of the License |
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4 "Eclipse Public License v1.0" which accompanies this distribution, |
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5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". --> |
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6 <!-- Initial Contributors: |
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7 Nokia Corporation - initial contribution. |
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8 Contributors: |
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9 --> |
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10 <!DOCTYPE concept |
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11 PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
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12 <concept id="GUID-EE50283A-543C-446F-A5D1-E64043F988ED" xml:lang="en"><title>DMA Device Driver Guide</title><shortdesc>Explains the key concepts that the device driver creator |
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13 needs to know before developing a device driver.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody> |
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14 <p>The DMA framework bypasses the CPU for data transfers. Without |
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15 DMA, the CPU would have to copy each piece of data from the source |
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16 to the destination.<ul> |
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17 <li><p><b>Device Driver:</b> A set of methods that tells the platform |
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18 how to use a specific piece of hardware.</p></li> |
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19 </ul><ul> |
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20 <li><p><b>DMA Framework:</b> The DMA framework provides a simplified |
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21 and unified access to DMA resources in a device. Generic transfer |
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22 parameters abstract the underlying DMA hardware for basic services, |
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23 and fine-grained control is still available for platform-specific |
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24 features. </p></li> |
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25 </ul><ul> |
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26 <li><p><b>DMA Operation:</b> Before any DMA transfers can be undertaken, |
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27 the DMA channel to be used and the source and destination addresses |
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28 of the data to be transferred have to be specified. The transfer details |
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29 are placed onto a queue for the DMA channel specified. The item at |
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30 the head of the queue will be the active transfer and the rest of |
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31 the queue will be pending transfers. </p></li> |
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32 </ul></p> |
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33 </conbody><related-links> |
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34 <link href="GUID-AB5370D9-9F0B-4583-A825-11CBF7C6365C.dita"><linktext>DMA |
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35 Tutorials Overview</linktext></link> |
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36 <link href="GUID-EDC1C30B-4078-4434-95AC-2E37AF809A51.dita"><linktext>DMA |
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37 Implementation Overview</linktext></link> |
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38 <link href="GUID-4E3C086B-25BE-4DAC-9E21-CFC4F8B792A5.dita"><linktext>DMA |
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39 Technology Guide</linktext></link> |
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40 </related-links></concept> |