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diff --git a/doc/src/platforms/emb-porting.qdoc b/doc/src/platforms/emb-porting.qdoc new file mode 100644 index 0000000..1afd1be --- /dev/null +++ b/doc/src/platforms/emb-porting.qdoc @@ -0,0 +1,193 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at http://qt.nokia.com/contact. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \page qt-embedded-porting-operatingsystem.html + + \title Porting Qt for Embedded Linux to Another Operating System + \ingroup qt-embedded-linux + + \l{Qt for Embedded Linux} is reasonably platform-independent, making use of + the standard C library and some POSIX functions, but only a Linux + implementation is publically available. If you are looking for a + non-Linux commercial implementation, it is worth contacting \l + {mailto:qt-info@nokia.com}{qt-info@nokia.com} to see if we can + help. + + There are several issues to be aware of if you plan to do your own + port to another operating system. In particular you must resolve + \l{Qt for Embedded Linux}'s shared memory and semaphores (used to share + window regions), and you must provide something similar to + Unix-domain sockets for inter-application communication. You must + also provide a screen driver, and if you want to implement sound + you must provide your own sound server. Finally you must modify + the event dispatcher used by \l{Qt for Embedded Linux}. + + Contents: + + \tableofcontents + + \section1 Shared Memory and Semaphores + + \l{Qt for Embedded Linux} uses System V IPC (shared memory and semaphores) + to share window regions between client and server. When porting, + something similar must be provided; otherwise it will not be + possible to run multiple applications. + + System V semaphores are also used for synchronizing access to the + framebuffer. + + \list + \o Modify \c qsharedmemory_p.cpp + \o Modify \c qlock_qws.cpp + \o Modify \c qwslock.cpp + \endlist + + \section1 Inter-Application Communication + + To communicate between applications, \l{Qt for Embedded Linux} uses the + Unix-domain sockets. When porting, something similar must be + provided; otherwise it will not be possible to run multiple + applications. + + It should be possible to use message queues or similar mechanisms + to achieve this. With the exception of QCOP messages, individual + messages should be no more than a few bytes in length (QCOP + messages are generated by the client applications and not Qt for + Embedded Linux). + + \list + \o Modify \c qwssocket_qws.cpp + \endlist + + \section1 Screen Management + + When rendering, the default behavior in \l{Qt for Embedded Linux} is + for each client to render its widgets into memory while the server is + responsible for putting the contents of the memory onto the screen + using the screen driver. + + When porting, a new screen driver must be implemented, providing a + byte pointer to a memory-mapped framebuffer and information about + width, height and bit depth (the latter information can most + likely be hard-coded). + + \list + \o Reimplement \c qscreen_qws.cpp + \endlist + + \section1 Sound Management + + To implement sound, \l{Qt for Embedded Linux} uses a Linux style device (\c + /dev/dsp). If you want to use the \l{Qt for Embedded Linux} sound server on + another platform you must reimplement it. + + \list + \o Reimplement \c qsoundqss_qws.cpp + \endlist + + \section1 Event Dispatching + + \l{Qt for Embedded Linux} uses an event dispatcher to pass events to and + from the \l{Qt for Embedded Linux} server application. Reimplement the \c + select() function to enable \l{Qt for Embedded Linux} to dispatch events on + your platform. + + \list + \o Modify \c qeventdispatcher_qws.cpp + \endlist +*/ + +/*! + \page qt-embedded-porting-device.html + + \title Porting Qt for Embedded Linux to a New Architecture + \ingroup qt-embedded-linux + + When porting \l{Qt for Embedded Linux} to a new architecture there are + several issues to be aware of: You must provide suitable hardware + drivers, and you must ensure to implement platform dependent + atomic operations to enable multithreading on the new + architecture. + + \section1 Hardware Drivers + + When running a \l{Qt for Embedded Linux} application, it either runs as a + server or connects to an existing server. All system generated + events, including keyboard and mouse events, are passed to the + server application which then propagates the event to the + appropriate client. When rendering, the default behavior is for + each client to render its widgets into memory while the server is + responsible for putting the contents of the memory onto the + screen. + + The various hardware drivers are loaded by the server + application when it starts running, using Qt's \l {How to Create + Qt Plugins}{plugin system}. + + Derive from the QWSMouseHandler, QWSKeyboardHandler and QScreen + classes to create a custom mouse, keyboard and screen driver + respectively. To load the drivers into the server application at + runtime, you must also create corresponding plugins. See the + following documentation for more details: + + \list + \o \l{Qt for Embedded Linux Pointer Handling}{Pointer Handling} + \o \l{Qt for Embedded Linux Character Input}{Character Input} + \o \l{Qt for Embedded Linux Display Management}{Display Management} + \endlist + + \section1 Atomic Operations + + Qt uses an optimization called \l {Implicitly Shared Classes}{implicit sharing} + for many of its value classes; implicitly shared classes can safely be + copied across threads. This technology is implemented using atomic + operations; i.e., \l{Qt for Embedded Linux} requires that platform-specific + atomic operations are implemented to support Linux. + + When porting \l{Qt for Embedded Linux} to a new architecture, it is + important to ensure that the platform-specific atomic operations + are implemented in a corresponding header file, and that this file + is located in Qt's \c src/corelib/arch directory. + + See the \l {Implementing Atomic Operations}{atomic operations} + documentation for more details. +*/ |