--- a/Symbian3/PDK/Source/GUID-58AA7257-0951-42AB-9B6E-AAF63343FEFA.dita Thu Mar 11 15:24:26 2010 +0000
+++ b/Symbian3/PDK/Source/GUID-58AA7257-0951-42AB-9B6E-AAF63343FEFA.dita Thu Mar 11 18:02:22 2010 +0000
@@ -1,102 +1,102 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
-<!-- This component and the accompanying materials are made available under the terms of the License
-"Eclipse Public License v1.0" which accompanies this distribution,
-and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
-<!-- Initial Contributors:
- Nokia Corporation - initial contribution.
-Contributors:
--->
-<!DOCTYPE concept
- PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
-<concept id="GUID-58AA7257-0951-42AB-9B6E-AAF63343FEFA" xml:lang="en"><title>DMA Channel Operations</title><shortdesc>This document describes how a device driver should open and close
-a DMA channel.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
-<section id="GUID-C4241738-D4C3-4171-87B2-5EDFFACE4002"><title>Open</title><p>To
-use a DMA channel it has to be opened. <xref href="GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37.dita#GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37/GUID-514BA285-3563-3C24-A067-F360098A6ADF"><apiname>TDmaChannel::Open()</apiname></xref> must
-be called to open the channel, and the required information provided in a <xref href="GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37.dita#GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37/GUID-6B973278-8BE7-3CE5-97D8-60E8D3F4D473"><apiname>TDmaChannel::SCreateInfo</apiname></xref> structure.
-The actual DMA channel selection is done by the hardware specific layer. The
-cookie passed to the <codeph>SCreateInfo</codeph> structure holds an object
-from the hardware specific layer, which provides the DMA channel information. </p> <codeblock id="GUID-A1CA8DBA-1378-502B-8CC8-6D83F13DD151" xml:space="preserve">/**
- Initializes the DMA for transmit. This function does all the
- required generic initialization to use the DMA framework. This
- function does not have any variant specific initializations.
- The implementation of the function can be the same on all
- variants, except if the variant has a different DFCQ buffer size.
-
- @return KErrNone on success, else standard error code on failure
- */
-TInt DExDriverUartTxDma::Init()
- {
- ...
-
- // Create the helper object for DMA transmit. This object
- // pointer is provided to System DMA controller driver during
- // channel operations such as opening, closing and starting
- //
- iHelper = new DExDriverTxDmaHelper(iUartComm);
- if (iHelper == NULL)
- {
- return KErrNoMemory;
- }
-
- // Initialize the channel information to select and configure the DMA
- // channel
- TDmaChannel::SCreateInfo info;
- info.iCookie = (TUint)iHelper;
- info.iDesCount = 1; // For single buffered transfers
- info.iDfcPriority = 4; // Set the priority of this DFC for DMA
- info.iDfcQ = iUartComm->DfcQ(); // DFCQ onto which this request
- // has to be queued
-
- // DMA channel has to be opened before doing any operations on
- // the channel. TDmaChannel::Open() opens the DMA channel as
- // set by info passed and selected by the hardware-specific layer.
- // Using the cookie, the helper class's ChannelOpen() is called
- // for DMA channel initialization.
- //
- r = TDmaChannel::Open(info, iTxDmaChannel);
- if (r!=KErrNone)
- {
- return r;
- }
- ...
- }</codeblock> </section>
-<section id="GUID-5E09A55C-A2B9-4E02-9BCF-F23558357B70"><title>Close</title> <p>A DMA channel has to be closed after completing
-all the DMA operations. This releases the DMA channel for other resources
-and peripherals. To close a previously opened channel, the channel should
-be idle, with no pending requests. So, before closing, call <xref href="GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37.dita#GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37/GUID-0A98D2DC-2A61-3FBD-AB7A-623FE926A183"><apiname>TDmaChannel::CancelAll()</apiname></xref>,
-which cancels the current request and any pending DMA requests. This should
-then be followed by closing the channel using <xref href="GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37.dita#GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37/GUID-8204AFBD-2A60-372E-B626-35BD19851FF7"><apiname>TDmaChannel::Close()</apiname></xref>. </p> <codeblock id="GUID-4BA5CDD2-6BD3-5179-89B8-7337ED5809AA" xml:space="preserve">/**
- Destructor. Deinitializes the member variables, cancels any
- requests, closes the channel, deletes the DMA requests, frees the
- hardware chunks allocated.
- */
-
-DExDriverUartTxDma::~DExDriverUarttxDma()
- {
- ...
- // if DMA channel is existing, cancel all requests on it.
- //
- if (iTxDmaChannel)
- {
- // TDmaChannel::CancelAll() cancels the current request and
- // any pending requests on the DMA channel
- //
- iTxDmaChannel->CancelAll();
- }
- ...
-
- if(iTxDmaChannel)
- {
- // Close the DMA channel. TDmaChannel::Close() closes a
- // previously opened channel. All the requests on this
- // channel should have been cancelled prior to this, i.e.
- // TDmaChannel::CancelAll() should have been called before
- // this call.
- //
- iTxDmaChannel->Close();
- }
- ...
- }</codeblock> <p>To stop DMA without closing the channel, simply cancel
-the request. </p></section>
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License
+"Eclipse Public License v1.0" which accompanies this distribution,
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+ Nokia Corporation - initial contribution.
+Contributors:
+-->
+<!DOCTYPE concept
+ PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="GUID-58AA7257-0951-42AB-9B6E-AAF63343FEFA" xml:lang="en"><title>DMA Channel Operations</title><shortdesc>This document describes how a device driver should open and close
+a DMA channel.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<section id="GUID-C4241738-D4C3-4171-87B2-5EDFFACE4002"><title>Open</title><p>To
+use a DMA channel it has to be opened. <xref href="GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37.dita#GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37/GUID-514BA285-3563-3C24-A067-F360098A6ADF"><apiname>TDmaChannel::Open()</apiname></xref> must
+be called to open the channel, and the required information provided in a <xref href="GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37.dita#GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37/GUID-6B973278-8BE7-3CE5-97D8-60E8D3F4D473"><apiname>TDmaChannel::SCreateInfo</apiname></xref> structure.
+The actual DMA channel selection is done by the hardware specific layer. The
+cookie passed to the <codeph>SCreateInfo</codeph> structure holds an object
+from the hardware specific layer, which provides the DMA channel information. </p> <codeblock id="GUID-A1CA8DBA-1378-502B-8CC8-6D83F13DD151" xml:space="preserve">/**
+ Initializes the DMA for transmit. This function does all the
+ required generic initialization to use the DMA framework. This
+ function does not have any variant specific initializations.
+ The implementation of the function can be the same on all
+ variants, except if the variant has a different DFCQ buffer size.
+
+ @return KErrNone on success, else standard error code on failure
+ */
+TInt DExDriverUartTxDma::Init()
+ {
+ ...
+
+ // Create the helper object for DMA transmit. This object
+ // pointer is provided to System DMA controller driver during
+ // channel operations such as opening, closing and starting
+ //
+ iHelper = new DExDriverTxDmaHelper(iUartComm);
+ if (iHelper == NULL)
+ {
+ return KErrNoMemory;
+ }
+
+ // Initialize the channel information to select and configure the DMA
+ // channel
+ TDmaChannel::SCreateInfo info;
+ info.iCookie = (TUint)iHelper;
+ info.iDesCount = 1; // For single buffered transfers
+ info.iDfcPriority = 4; // Set the priority of this DFC for DMA
+ info.iDfcQ = iUartComm->DfcQ(); // DFCQ onto which this request
+ // has to be queued
+
+ // DMA channel has to be opened before doing any operations on
+ // the channel. TDmaChannel::Open() opens the DMA channel as
+ // set by info passed and selected by the hardware-specific layer.
+ // Using the cookie, the helper class's ChannelOpen() is called
+ // for DMA channel initialization.
+ //
+ r = TDmaChannel::Open(info, iTxDmaChannel);
+ if (r!=KErrNone)
+ {
+ return r;
+ }
+ ...
+ }</codeblock> </section>
+<section id="GUID-5E09A55C-A2B9-4E02-9BCF-F23558357B70"><title>Close</title> <p>A DMA channel has to be closed after completing
+all the DMA operations. This releases the DMA channel for other resources
+and peripherals. To close a previously opened channel, the channel should
+be idle, with no pending requests. So, before closing, call <xref href="GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37.dita#GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37/GUID-0A98D2DC-2A61-3FBD-AB7A-623FE926A183"><apiname>TDmaChannel::CancelAll()</apiname></xref>,
+which cancels the current request and any pending DMA requests. This should
+then be followed by closing the channel using <xref href="GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37.dita#GUID-83882548-FAC5-3EFF-92ED-14D1D9A85D37/GUID-8204AFBD-2A60-372E-B626-35BD19851FF7"><apiname>TDmaChannel::Close()</apiname></xref>. </p> <codeblock id="GUID-4BA5CDD2-6BD3-5179-89B8-7337ED5809AA" xml:space="preserve">/**
+ Destructor. Deinitializes the member variables, cancels any
+ requests, closes the channel, deletes the DMA requests, frees the
+ hardware chunks allocated.
+ */
+
+DExDriverUartTxDma::~DExDriverUarttxDma()
+ {
+ ...
+ // if DMA channel is existing, cancel all requests on it.
+ //
+ if (iTxDmaChannel)
+ {
+ // TDmaChannel::CancelAll() cancels the current request and
+ // any pending requests on the DMA channel
+ //
+ iTxDmaChannel->CancelAll();
+ }
+ ...
+
+ if(iTxDmaChannel)
+ {
+ // Close the DMA channel. TDmaChannel::Close() closes a
+ // previously opened channel. All the requests on this
+ // channel should have been cancelled prior to this, i.e.
+ // TDmaChannel::CancelAll() should have been called before
+ // this call.
+ //
+ iTxDmaChannel->Close();
+ }
+ ...
+ }</codeblock> <p>To stop DMA without closing the channel, simply cancel
+the request. </p></section>
</conbody></concept>
\ No newline at end of file