rtems-gdb-stub

1.Ns3 的安装：开发环境配置：sudo apt-get install gcc g++ python python-dev //C++和python安装，必装sudo apt-get install mercurial //NS3代码维护使用的源码版本控制管理系统sudo apt-get install bzr //运行python绑定ns-3-dev需要bazaar这个组件sudo apt-get install libgtk2.0-0 libgtk2.0-dev //基于GTK的配置系统sudo apt-get install gdb valgrind //调试工具sudo apt-get install doxygen graphviz imagemagick //文档生成器sudo apt-get install texlive texlive-latex-extra //文档生成器，从源代码中生成说明文档sudo apt-get install texinfo dia texlive-extra-utils texi2html //ns-3手册和tutorial编写查看工具sudo apt-get install flex bison //仿真必需的词法分析器和语法分析生成器，必装sudo apt-get install libgoocanvas-dev //部分移动场景仿真的可视化测试需要这个组件sudo apt-get install tcpdump //读取pcap的packet traces，即包嗅探器sudo apt-get install sqlite sqlite3 libsqlite3-dev //支持统计特性的数据库软件sudo apt-get install libxml2 //xml的配置存储软件sudo apt-get install python-pygraphviz python-kiwi python-pygoocanvas //Gustavo's ns-3-pyviz的可视化软件sudo apt-get install qt4-qmakesudo apt-get install qt4-dev-tools安装完成后：进入ns-allinone-3.16目录sudo ./build.py之后进入ns-allinone-3.16/ns-3.16sudo ./waf -check返回目录ns-allinone-3.16进入目录netanim-3.103sudo make cleansudo qmake NetAnim.prosudo make之后sudo ls可以看见绿色的NetAnim这个东西就成功了sudo ./NetAnim 打开仿真界面安装全部完成2.ns3仿真的运行ctrl+alt+t调出终端，进入ns-allinone-3.16目录，输入cd ns-3.16/ 进入ns-3.16文件夹输入cd examples/tutorial/ 进入examples里面的tutorial文件夹（里面有刚刚上手专用的实例，我们就用这个来调试）在tutorial目录下，输入cp ~/ns-allinone/ns-3.16/scratch/ ，将这个文件复制到ns-3.16的scratch文件夹里面. 具体位置由实际的自己的计算机的文件目录所定。

Board Porting\Bring up using Processor SDK RTOS for AM335xProcessor SDK RTOS component known as board library consolidates all the board-specific information so that all the modifications made when moving to a new custom platform using the SOC can be made in the source of this library.There are three different components in PRSDK that help in porting and bring up of a custom board:∙Board library updatesa.PLL Clocking and PRCMb.Pin mux Updatec.DDR Configurationd.Peripheral instances updates∙Diagnostics tests∙Boot loader updatesBoard Library Updates in Processor SDK RTOS:PLL ClockingThere are two places where the device PLL configurations are performed when using Processor SDK RTOS and CCS.Debug environment:Debug environment refers to development setup where code is debugged using JTAG emulator on the SOC. The PRSDK software relies on the GEL file that is part of the target configuration to setup the clocks and the DDR for the device. The CCS GEL file for AM335x platforms is located in the CCS package at the location ccsv7\ccs_base\emulation\boards\<boardName>For example for beagle bone black, the files can be found atccsv7\ccs_base\emulation\boards\beaglebone\gelThe GEL is the first piece of software that should be brought up on a custom board.Production environment:Production environment refers to the setup when the base application is booted from a boot media like a flash memory or host interface. In this environment, the bootloader sets performs all the SOC and board initialization and copies the application from flash memory to the device memory.The clock setup in the bootloader code can be located atpdk_am335x_x_x_x\packages\ti\starterware\bootloader\src\am335xUsers can choose to use the platform clocking similar to one of TI reference platforms or can modify them as per their application requirements. By default the PLL settings are setup for OPP_NOM settings (MPU= 600 MHz.)TI provides Clock Tree tool to allow users to simulate the clocking on the SOC. For quick reference of the multiplier and divider settings to change the PLL setting is provided in the spreadsheetAM335x_DPLL_CALCv3.xlsx.After modifying the clocking in the bootloader, users need to rebuild the bootloader using instructions provided in Processor_SDK_RTOS_BOOT_AM335x/AM437xPRCM Modules Enable:PRCM Module Enable is required to turn on the power domain and the clocking to each of the modules on the SOC. The PRCM Enable calls to enable each module are made from the functionBoard_moduleClockInit which is found in the location.pdk_am335x_1_0_9\packages\ti\board\src\bbbAM335x\bbbAM335x.cCheck every instance and peripheral required in the application platform and enable the module in the board library.For example to use three UARTs 0, 1 and 4, ensure that you have the following code as part of the board library setup:/* UART */status = PRCMModuleEnable(CHIPDB_MOD_ID_UART, 0U, 0U);status = PRCMModuleEnable(CHIPDB_MOD_ID_UART, 1U, 0U);status = PRCMModuleEnable(CHIPDB_MOD_ID_UART, 4U, 0U);Note: PRCMEnable function is defined in pdk_am335x_1_0_9\packages\ti\starterware\soc\am335x Pinmux updates in the Board library:Generating a New PinMux Configuration Using the PinMux Utility: This procedure uses the cloud-based pinmux utilityNavigate to ${PDK_INSTALL_DIR}\packages\ti\starterware\tools\pinmux_config\am335x and Load beaglebone_black_configAdd and remove peripheral instances and select the appropriate use cases required for development based on the application platform requirements and resolve all conflicts.Refer Pin_Mux_Utility_for_ARM_MPU_ProcessorsPost Processing steps:1.Change the Category filter to starterware and download the pinmux files am335x_pimnmux.hand am335x_pinmux_data.c2.At the bottom of am335x_pinmux.h change extern pinmuxBoardCfg_t gAM335xPinmuxData[];to extern pinmuxBoardCfg_t gBbbPinmuxData[];3.Change am335x_pinmux_data.c to am335x_beagleboneblack_pinmux_data.c.4.Change gAM335xPinmuxData to gBbbPinmuxData at the end of the file in file5.am335x_beagleboneblack_pinmux_data.c.Replace the existing files with the new files and rebuild the board library using the instructions in the section Rebuilding board Library in Processor SDK RTOS:Updating DDR settings:Similar to clock and PLL settings, DDR initialization is configured in the Debug environment through GEL files and in production environment using bootloader source files.TI provides AM335x_EMIF_Configuration_tips which contains a spreadsheet to enter the timing from the DDR datasheet to compute the EMIF timing number required to initialize DDR.We strongly recommend changing the value and testing using GEL files before using them in the bootloader software. For Sanity test, you can perform read/write tests using CCS Memory Browser or run the diagnostic memory read/write test that we provide in diagnostics package here:PDK_INSTALL_PATH\packages\ti\board\diag\memOnce the DDR timings have been confirmed, you can use the settings in the file:PDK_INSTALL_PATH \packages\ti\starterware\bootloader\src\am335x\sbl_am335x_platform_ddr.c Peripheral initialization:The board library is responsible for most of the SOC initialization but it also setup some board level components such as ethernet PHY and debug UART and I2C for reading board ID from EEPROM. All of the other peripheral instances and initialization needs to be done from the application level.For example for beagleboneblack, the peripheral initialization are performed from the source filepdk_am335x_1_0_9\packages\ti\board\src\bbbAM335x\bbbAM335x_lld_init.cThe debug UART instance, I2C Addresses are set using the file board_cfg.h found under:pdk_am335x_1_0_9\packages\ti\board\src\bbbAM335x\includeDefault UART instance is set to 0 in the board library. The Board initialization will configure the UART instance 0 to send binary log data to serial console using the Board_UARTInit function. If you wish to use more UART instances then we recommend linking in the UART driver in the application and using UART_open() and UART_stdioInit API calls from the application.Each peripheral driver in the Processor SDK RTOS has a SOC configuration that provides the interrupt numbers, base address, EDMA channels which can be updated using the file <peripheral>_soc.c file. This is used as default setup for initializing the driver instance. It can be overridden from the application using peripheral_getSOCInitCfg() and peripheral_setSOCInitCfg()For Example: All instances of UART for AM335x have been mapped in the filepdk_am335x_1_0_9\packages\ti\drv\uart\soc\am335x\UART_soc.cSystem integrators need to ensure that no interrupt numbers and EDMA resource conflicts exist in the SOC configuration for all drivers used in the system.To exercise three UARTs in the system, users can use the following code://Setup Debug UARTboardCfg = BOARD_INIT_PINMUX_CONFIG |BOARD_INIT_MODULE_CLOCK |BOARD_INIT_UART_STDIO;Board_init(boardCfg);// Open Additional UART Instances:/* UART SoC init configuration */UART_initConfig(false);/* Initialize the default configuration params. */UART_Params_init(&uartParams);// Open UART Instance 1uartTestInstance =1;uart1 = UART_open(uartTestInstance, &uartParams);//Open UART Instance 4uartTestInstance = 4;uart4 = UART_open(uartTestInstance, &uartParams);BoardID Detect:TI supports multiple evaluation and reference platforms for AM335x hence the hardware platforms are populated with an EEPROM which contains information that identifies the hardware and its revision. The board library and software components read the boardID and initialize the platform based on the boardID. The BoardID_detect function can be found in the source in the file bbbAM335x_info.c in the board library and board_am335x.c in the bootloader source at:<PDK_INSTALL_PATH>\packages\ti\starterware\board\am335xRebuilding board Library in Processor SDK RTOS:While Creating a new folder for the custom board is an option users can explore, TI recommends that users make there changes in existing board package using either bbbAM335x, evmAM335x oriceAM335x folder to avoid spending additional effort to modify the build files for including the customBord.Once all the update to the board library are completed, the board library can be updated using the following instructions.Instructions to rebuild board library:Setup Processor SDK build environment before following steps provided below.cd pdk_am335x_1_0_9\packagesgmake board_libFor a specific board users are required to provide the LIMIT_BOARDS argument.LIMIT_BOARDS : evmAM335x icev2AM335x iceAMIC110 bbbAM335x skAM335xFor Example for beagleboneblack, users can use the following build option:gmake board_lib LIMIT_BOARDS=bbbAM335xDiagnostics:After the board library is built, we highly recommend that you create a diagnostics package similar to one provided in board library to test different interfaces functionally during board bring up.The diagnostics package can be located at pdk_am335x_1_0_9\packages\ti\board\diag. These are simple bare-metal tests that use peripheral drivers to help functionally validate the pins and interfaces.Documentation for all available diagnostic tests is provided here:/index.php/Processor_SDK_RTOS_DIAGBootloader in Processor SDK RTOS:As part of the production flow, users are required to develop/port flashing and booting utilities so the application can be launched on the custom board with JTAG. TI provides a bootloader mechanism where the ROM bootloader loads a secondary bootloader on the onchip memory that initializes the SOC and DDR and then copies the application into DDR memory.The boot process and flashing tools have been described in detail in the following article that is part of processor SDK RTOS Software developer`s guide:/index.php/Processor_SDK_RTOS_BOOT_AM335x/AM437x#Building_the_B ootloader。

gem5模拟器使⽤介绍（⼀）gem5简介：关于gem5的详细介绍，其官⽅论坛上有，这⾥不再详述，给出重点的总结：⼀、gem5模拟器是⼀款⾼度可配置、集成多种ISA和多种CPU模型的体系结构模拟器,它是结合了M5和GEMS中最优秀的部分⽽形成的。

⼆、gem5的功能是⾮常强⼤的，它⽀持：1、SE和FS两种模式的系统模型（其中FS模式的系统模型对于典型的交互式应⽤下系统性能的测试是很有⽤的）；2、从简单到复杂分别是Atomic、Timing、In- order、O3（Out of Order）的四种CPU模型；3、Classic和Ruby两种存储器模型。

gem5编译过程：（这⼀部分参考了部分官⽹和⽹上前辈的资料，补充了⾃⼰实践中的思考）软硬件环境：intel(64)+ubuntu12.04(64)+gem5-stablegem5模拟器的安装过程可以分为两个阶段：第⼀个阶段是下载gem5的源码包（1）并配置安装gem5的环境（2、3）；第⼆个阶段是根据⾃⼰模拟的需求选择相关的选项或这⾃⼰创建脚本，利⽤安装好的⼯具对gem5源码包进⾏编译安装（4）并进⾏调试（5）。

1、下载gem5源代码包在gem5的官⽹（/Download）上⾯提供了最新版本的和稳定版本的gem5源码包都可以下载安装，⼀般选⽤stable版本的gem5源码包进⾏下载安装。

2、安装g++编译器，需要注意版本（g++4.5）为了对gem5源码包和以后需要在gem5上运⾏的C和C++程序进⾏编译需要合适版本的g++，推荐使⽤g++4.5版本的。

3、依次安装python（version 2.4 - 2.7）、scons（version 0.98.1 or newer.）、swig（version 1.3.34 or newer）、zlib、m4这些gem5所依靠的⼯具和环境。

gem5是连接到python解析器的因此需要python的头⽂件和⼀些共享库，所以必须安装python(版本要⾼于2.4，安装前可以查看系统是否已经⾃带，若⾃带则不需要安装)；gem5的安装是通过scons⼯具完成的，因此需要安装scons(版本在0.98.1之上)。

1 前言rt-thread可以采用软件定时器或硬件定时器来实现定时器管理的，所谓软件定时器是指由操作系统提供的一类系统接口，它构建在硬件定时器基础之上，使系统能够提供不受数目限制的定时器服务。

而硬件定时器是芯片本身提供的定时功能。

一般是由外部晶振提供给芯片输入时钟，芯片向软件模块提供一组配置寄存器，接受控制输入，到达设定时间值后芯片中断控制器产生时钟中断。

硬件定时器的精度一般很高，可以达到纳秒级别，并且是中断触发方式。

软件定时器的精度取决于它使用的硬件定时器精度。

而rt-thread 操作系统在默认情况下是采用的硬件定时器的方式，用户可以通过修改宏定义#ifdefRT_USING_TIMER_SOFT来修改采用哪种。

2 rt-thread的定时器的基本工作原理在RT-Thread定时器模块维护两个重要的全局变量，一个是当前系统的时间rt_tick（当硬件定时器中断来临时，它将加1），另一个是定时器链表rt_timer_list，系统中新创建的定时期都会被以排序的方式插入到rt_timer_list(硬件定时器模式下使用)链表中,rt_timer_list的每个节点保留了一个定时器的信息，并且在这个节点加入链表时就计算好了产生时间到达时的时间点，即tick,在rt-thread系统中如果采用软件定时器模式，则存在一定时器线程rt_thread_timer_entry，不断获取当前TICK值并与定时器链表rt_timer_list上的定时器对比判断是否时间已到，一旦发现就调用对应的回调函数，即事件处理函数进行处理，而如果采用硬件定时器管理模式的话，则该检查过程放到系统时钟中断例程中进行处理，此时，是不存在定时器线程的。

如下图：注：如果采用软件定时器软件定时器，则该定时器链表为rt_soft_timer_list。

3 源码分析3.1 数据定义[cpp]view plaincopyprint?1. /**2. * timer structure3. */4. struct rt_timer5. {6. struct rt_object parent; //内核对象7.8. rt_list_t list; //链表节点9.10. void (*timeout_func)(void *parameter); //定时器超时例程11. void *parameter; //定时器例程的传入参数12.13. rt_tick_t init_tick; //定时器的超时时间,即总共多长时间将产生超时事件14. rt_tick_t timeout_tick; //定时器超时的时间点，即产生超时事件时那一该的时间点15. };16. t ypedef struct rt_timer *rt_timer_t;3.2 rt-thread的软件定时器模式软件定时器线程初始化及启动:[cpp]view plaincopyprint?1. /**2. * @ingroup SystemInit3. *4. * This function will initialize system timer thread5. */6. void rt_system_timer_thread_init(void)7. {8. #ifdef RT_USING_TIMER_SOFT//如果采用软件定时器管理模式，则启动定时器线程9. rt_list_init(&rt_soft_timer_list);//初始化软件定时器链表10.11. /* start software timer thread */12. rt_thread_init(&timer_thread,//初始化软件定时器线程，并启动13. "timer",14. rt_thread_timer_entry,15. RT_NULL,16. &timer_thread_stack[0],17. sizeof(timer_thread_stack),18. RT_TIMER_THREAD_PRIO,19. 10);20.21. /* startup */22. rt_thread_startup(&timer_thread);23. #endif24. }软件定时器线程如下：[cpp]view plaincopyprint?1. /* system timer thread entry */2. static void rt_thread_timer_entry(void *parameter)3. {4. rt_tick_t next_timeout;5.6. while (1)7. {8. /* get the next timeout tick */9. next_timeout = rt_timer_list_next_timeout(&rt_soft_timer_list);//得到软件定时器链表上的下一个定时器的超时时间点10. if (next_timeout == RT_TICK_MAX)//如果超过范围，则挂起当前线程，继续线程调度11. {12. /* no software timer exist, suspend self. */13. rt_thread_suspend(rt_thread_self());14. rt_schedule();15. }16. else17. {18. rt_tick_t current_tick;19.20. /* get current tick */21. current_tick = rt_tick_get();//获取当前时间点22.23. if ((next_timeout - current_tick) < RT_TICK_MAX/2)//离下个中断时间点还差些时候24. {25. /* get the delta timeout tick */26. next_timeout = next_timeout - current_tick;//计算还差多长时间27. rt_thread_delay(next_timeout);//休眠一段时间28. }29. }30.31. /* lock scheduler */32. rt_enter_critical();//时间到，进入临界区33. /* check software timer */34. rt_soft_timer_check();//检查是否该产生超时事件35. /* unlock scheduler */36. rt_exit_critical();//退出临界区37. }38. }检查是否产生中断函数rt_soft_timer_check函数如下定义:[cpp]view plaincopyprint?1. /**2. * This function will check timer list, if a timeout event happens, the3. * corresponding timeout function will be invoked.4. */5. void rt_soft_timer_check(void)6. {7. rt_tick_t current_tick;8. rt_list_t *n;9. struct rt_timer *t;10.11. RT_DEBUG_LOG(RT_DEBUG_TIMER, ("software timer check enter\n"));12.13. current_tick = rt_tick_get();//得到当前时间点14.15. for (n = rt_soft_timer_list.next; n != &(rt_soft_timer_list);)//得到下一定时器节点16. {17. t = rt_list_entry(n, struct rt_timer, list);//t指向rt_timer定时器18.19. /*20. * It supposes that the new tick shall less than the half duration of21. * tick max.22. */23. if ((current_tick - t->timeout_tick) < RT_TICK_MAX / 2)//如果当前的时间点超过定时器的超时时间点24. {25. RT_OBJECT_HOOK_CALL(rt_timer_timeout_hook, (t));//使用钩子函数26.27. /* move node to the next */28. n = n->next;//指向下一定时器29.30. /* remove timer from timer list firstly */31. rt_list_remove(&(t->list));//移除当前定时器32.33. /* call timeout function */34. t->timeout_func(t->parameter);//产生定时器超时事件，调用对应处理函数35.36. /* re-get tick */37. current_tick = rt_tick_get();//再次获取当前时间点38.39. RT_DEBUG_LOG(RT_DEBUG_TIMER, ("current tick: %d\n", current_tick));40.41. if ((t->parent.flag & RT_TIMER_FLAG_PERIODIC) &&//如果当前定时器是周期性定时器，则将其再次按序放入软件定时器链表42. (t->parent.flag & RT_TIMER_FLAG_ACTIVATED))43. {44. /* start it */45. t->parent.flag &= ~RT_TIMER_FLAG_ACTIVATED;//置标志为非激活状态46. rt_timer_start(t);//再次将定时器t放入软件定时器链表末尾47. }48. else49. {50. /* stop timer */51. t->parent.flag &= ~RT_TIMER_FLAG_ACTIVATED;//置标志为非激活状态52. }53. }54. else break; /* not check anymore */55. }56.57. RT_DEBUG_LOG(RT_DEBUG_TIMER, ("software timer check leave\n"));58. }上面代码中，为什么定时器里判断超时的条件是((current_tick - t→timeout_tick) < RT_TICK_MAX/2)？因为系统时钟溢出后会自动回绕。