再谈 EDK

1. 再谈EDK 赵峰 上海交通大学微电子学院

2. Knowledge Check • What is the MHS file? • What does the PlatGen tool do? • What tool is used to place executable code in an FPGA block RAM?

3. Answers • What is the MHS file? • The MHS file is the Microprocessor Hardware Specification; it specifies processors, hardware peripherals, bus connections, and address spaces for the hardware • What does the PlatGen tool do? • PlatGen takes the MHS file and creates the system and peripheral netlists, HDL wrapper files, BMM file, etc. • What tool is used to place executable code in an FPGA block RAM? • The Data2Mem tool will take the BMM file and create the proper initialization for the block RAM that is assigned to the executable memory space

4. Knowledge Check • How can you add or change configuration settings once the hardware system is build? • What does the LibGen tool do? • What is the difference between system.bit and download.bit files?

5. Answers • How can you add or change configuration settings once the hardware system is build? • Select IP Catalog tab, expand related IP peripheral folder, select a desired IP, and double-click on it to add it to the design • Select an IP instance in the System Assembly View panel, right click on it, and select desired configuration • What does the LibGen tool do? • Read MSS file and generate libraries • What is the difference between system.bit and download.bit files? • The system.bit file contains only hardware description whereas download.bit file contains both hardware description as well as executable software

6. VHDL or Verilog C Code Standard Embedded SW Development Flow Standard FPGA HW Development Flow Embedded Development Kit Code Entry HDL Entry C/C++ Cross Compiler Simulation/Synthesis Board Support Package System Netlist Data2MEM Linker Implementation Compiled ELF Compiled ELF Compiled BIT Compiled BIT ? ? Download Combined Image to FPGA Load Software Into FLASH Download Bitstream Into FPGA Debugger Chipscope Embedded DevelopmentTool Flow Overview Instantiate the ‘System Netlist’ and Implement the FPGA Include the BSP and Compile the Software Image 2 3 1 RTOS, Board Support Package

7. Embedded System Tools • GNU software development tools • C/C++ compiler for the MicroBlaze™ and PowerPC™ processors (gcc) • Debugger for the MicroBlaze and PowerPC processors (gdb) • Hardware and software development tools • Base System Builder Wizard • Hardware netlist generation tool: PlatGen • Software Library generation tool: LibGen • Simulation model generation tool: SimGen • Create/Import Peripherals Wizard • Xilinx Microprocessor Debug (XMD) • Hardware debugging using ChipScope™ Pro Analyzer cores • Eclipse IDE-based Software Development Kit (SDK) • Application code profiling tools • Virtual Platform generator: VPGen • Flash Writer utility

8. EDK Tool Flow Simulation Generator Library Generation Hardware Platform Generation CompEDKLib CompXLib MSS MHS TestbenchStimulus IP Models ISE Models IP Library or User Repository SimGen EDK SWLibraries Drivers,MDD LibGen MPD, PAO PlatGen .a PCoreHDL System andWrapper VHD BehavioralVHD Model system.BMM ISETools Synthesis (XST) Embedded Software Development NGC ApplicationSource.c, .h, .s SimGen UCF NGDBuild NGD Compiler (GCC) StructuralVHD Model MAP .o NCD, PCF Linker (GCC) PAR NCD system.BIT BitGen SimGen system_BD.BMM ELF BitInit TimingVHD Model download.BIT Simulation download.CMD iMPACT

9. Hardware Creation Flow • Platform Generator – PlatGen • Input file → MHS and MPD • MHS file defines the configuration of the embedded processor system including bus architecture, peripherals and processor(s), interrupt request priorities, and address space • MPD file defines the configurable parameters with their default values and available ports for a peripheral • Output files → system netlist, peripheral netlists, and BMM file • Creates the synthesis, HDL, and implementation directories • Generates the HDL wrapper files for the peripherals • Generates the top-level system HDL file • Extracts the peripheral netlists from the EDK install directory • Generates the BMM file • Calls XST to synthesize the top-level wrapper file

10. Software Flow Library Generation • Library Generator – LibGen • Input files → MSS • Output files → libc.a, libXil.a, libm.a • LibGen is generally the first tool run to configure libraries and device drivers • The MSS file defines the drivers associated with peripherals, standard input/output devices, interrupt handler routines, and other related software features • LibGen configures libraries and drivers with this information and produces an archive of object files: • libc.a - Standard C library • libXil.a - Xilinx library • libm.a - Math functions library

11. GNU Tools: GCC • GCC translates C source code into assembly language • GCC also functions as the user interface to the GNU assembler and to the GNU linker, calling the assembler and the linker with the appropriate parameters • Supported cross-compilers: • PowerPC processor compiler • GNU GCC (powerpc-eabi-gcc) • Wind River Diab compiler (dcc) • MicroBlaze processor compiler • GNU GCC (mb-gcc) • Command line only; uses the settings set through the GUI C files Cross-compiler Assembly files

12. GNU Tools • Calls four different executables • Preprocessor (cpp0) • Language specific c-compiler • cc1 C-programming language • cc1plus C++ language • Assembler • mb-as (MicroBlaze processor) • powerpc-eabi-as (PowerPC processor) • Linker and loader • mb-ld (MicroBlaze processor) • powerpc-eabi-ld (PowerPC processor)

13. GNU Tools: AS • Input: Assembly language files • File extension: .s • Output: Object code • File extension: .o • Contains • Assembled piece of code • Constant data • External references • Debugging information • Typically, the compiler automatically calls the assembler • Use –Wa switch if the source files are assembly only and use gcc Assembly files Cross-assembler Object files

14. GNU Tools: LD • Linker • Inputs: • Several object files • Archived object files (library) • Linker script (mapfile) • Outputs: • Executable image (.ELF) • Mapfile (different from linker script) Object files Linker script Linker/Locator Executable Map

15. Binutils: Binary Utilities • AR Archiver • Create, modify, and extract from libraries • Used in EDK to combine the object files of the Board Support Package (BSP) in a library • Used in EDK to extract object files from different libraries • OBJDUMP • Display information from object files and executables • Header information, memory map • Data • Disassemble code • GNU executables • powerpc-eabi-objdump • mb-objdump

16. Powerpc-eabi-objdump Text section Memorylocation Machinecode Assemblyinstructions

17. Address Management • Embedded processor design requires you to manage the following: • Address map for the peripherals • Location of the application code in the memory space • Block RAM • External memory • Memory requirements for your programs are based on the following: • The amount of memory required for storing the instructions • The amount of memory required for storing the data associated with the program

18. 0xFFFF_FFFC Reset Address PLB/OPB Memory 0xFFFF_0000 PLB/OPB Memory Peripherals 0x0000_0000 PowerPC Processor • Memory and peripherals • PPC405 uses 32-bit addresses • Special addresses • Every PowerPC™ system should havethe boot section starting at0xFFFFFFFC • Default linker options • Program space occupies a contiguousaddress space from 0xFFFF0000 to0xFFFFFFFF • Stack size: 4 KB • Heap size: 4 KB

19. Advanced User Address Space • Different base address, contiguous user address space • The user program can run from any memory PLB, OCM, OPB, or LMB • To execute a program from any address location other than default, you must provide the compiler gcc with a Program Start Address

20. Advanced UserAddress Space • Different base address, noncontiguous user address space • You can place different components of your program in different memories • For example, on PowerPC systems, you can keep your code on instruction cache memory and the data on ZBT memory • Noncontiguous executables that represent the application must be created • To do this, a linker script must be used

21. Object File Sections • What is an object file? • An object file is an assembled piece of code • Machine language: li r31,0 = 0x3BE0 0000 • Constant data • There may be references to external objects that are defined elsewhere • This file may contain debugging information

22. Object File Sections .text .rodata .sdata2 .data .sdata .sbss .bss Text section Read-only data section Small read-only data section (less than eight bytes) Read-write data section Small read-write data section Small uninitialized data section Uninitialized data section

23. Object File Sections .init .fini .ctors .dtors .got2 .got .eh_frame Language initialization code Language cleanup code List of functions to be invoked at program startup List of functions to be invoked at program end Pointers to program data Pointers to program data Frame unwind information for exception handling

24. Sections Example int ram_data[10] = {0,1,2,3,4,5,6,7,8,9}; /* DATA */ const int rom_data[10] = {9,8,7,6,5,4,3,2,1}; /* RODATA */ int I; /* BSS */ main(){ ... I = I + 10; /* TEXT */ ... }

25. Linker Scripts • Linker scripts • Control the linking process • Map the code and data to a specified memory space • Set the entry point to the executable • Reserve space for the stack • Required if the design contains a discontinuous memory space

26. Link Linker and Locator Flows Executable Image foo1.o Merged Output Sections 0xFFFF .text1 Code .text .data1 0xF000 Locate 0xEFFF .bss1 uninitialized data 0xEF00 .data 0xEEFF foo2.o .bss Unused .text2 0x2000 .data2 0x1FFF Initialized data .bss2 0x0000

27. PowerPC Processor Boot Files • Files: boot.S, boot0.S, crt0.S, eabi.S • Application entry point at label _boot in boot.S • _boot is single jump instruction to _boot0 • _boot0 is a few instructions that do a jump to _start in crt0.S • _start • Clears .bss and .sbss sections • Sets up stack on an eight byte alignment • Initializes time-base registers to zero • Optionally, enable FPU bit in MSR • Calls main() • Calls _eabi to set R13 and R2 registers to point to .sdata and .sdata2 sections respectively • Performs user tasks

28. PowerPC Processor Script Example STACKSIZE = 4k; MEMORY { ddr : ORIGIN = 0x00000000, LENGTH = 32m sram : ORIGIN = 0x10000000, LENGTH = 2m flash : ORIGIN = 0x18000000, LENGTH = 32m bram : ORIGIN = 0xffff8000, LENGTH = 32k - 4 boot : ORIGIN = 0xfffffffc, LENGTH = 4 } SECTIONS { .text : { *(.text) } > bram .boot : { *(.boot) } > boot .data : { *(.data) *(.got2) *(.rodata) *(.fixup)} > bram .bss : { *(.bss) } > bram __bss_start = ADDR(.bss); __bss_end = ADDR(.bss) + SIZEOF(.bss); }

29. Sections Command • This is where most of the work takes place • Output sections are named, and the input sections are grouped and linked together into the output sections • Example: • Explanation: • .text is the name of the output section • { *(.text) *.(init) } includes all input sections named text and init from the object files being linked • > bram locates the .text output section in the next available memory in the block RAM area • .text : { *(.text) *(.init) } > bram

30. Linker Script Generator GUI • XPS contains a graphical Linker Script Generator • Table-based GUI allows you to define the memory space for any section • Launch from Software → Generate LinkerScript, or from the Applications Tab, right-click on <project> → Generate LinkerScript • The tool will create a new linker script (the old script is backed up)

31. Drivers: Level 0 / Level 1 • The layered architecture provides seamless integration with… • (Layer 2) RTOS application layer • (Layer 1) High-level device drivers that are full-featured and portable across operating systems and processors • (Layer 0) Low-level drivers for simple use cases

32. Drivers: Level 0 • Consists of low-level device drivers • Implemented as macros and functions that are designed to allow a developer to create a small system • Characteristics: • Small memory footprint • Little to no error checking is performed • Supports primary device features only • No support of device configuration parameters • Supports multiple instances of a device with base address input to the API • Polled I/O only • Blocking function calls • Header files have “_l” in their names (e.g. xuartlite_l.h)

33. Drivers: Level 1 • Consists of high-level device drivers • Implemented as macros and functions and designed to allow a developer to utilize all of the features of a device • Characteristics: • Abstract API that isolates the API from hardware device changes • Supports device configuration parameters • Supports multiple instances of a device • Polled and interrupt driven I/O • Non-blocking function calls to aid complex applications • May have a large memory footprint • Typically, provides buffer interfaces for data transfers as opposed to byte interfaces • Header files do not have “_l” in their names (e.g. xuartlite.h)

34. Comparison Example • Uartlite Level 1 • XStatus XUartLite_Initialize (XUartLite *InstancePtr, Xuint16 DeviceId) • void XUartLite_ResetFifos (XUartLite *InstancePtr) • unsigned int XUartLite_Send (XUartLite *InstancePtr, Xuint8 *DataBufferPtr, unsigned int NumBytes) • unsigned int XUartLite_Recv (XUartLite *InstancePtr, Xuint8 *DataBufferPtr, unsigned int NumBytes) • Xboolean XUartLite_IsSending (XUartLite *InstancePtr) • void XUartLite_GetStats (XUartLite *InstancePtr, XUartLite_Stats *StatsPtr) • void XUartLite_ClearStats (XUartLite *InstancePtr) • XStatus XUartLite_SelfTest (XUartLite *InstancePtr) • void XUartLite_EnableInterrupt (XUartLite *InstancePtr) • void XUartLite_DisableInterrupt (XUartLite *InstancePtr) • void XUartLite_SetRecvHandler (XUartLite *InstancePtr, XUartLite_Handler FuncPtr, void *CallBackRef) • void XUartLite_SetSendHandler (XUartLite *InstancePtr, XUartLite_Handler FuncPtr, void *CallBackRef) • void XUartLite_InterruptHandler (XUartLite *InstancePtr) • Uartlite Level 0 • void XUartLite_SendByte (Xuint32 BaseAddress, Xuint8 Data) • Xuint8 XUartLite_RecvByte (Xuint32 BaseAddress)

35. Exceptions and Interrupts • Exceptions are events detected by the processor that require action by the system software • Typically, the result of unexpected error conditions (e.g., bus error) • Some exceptions can be programmed to occur (e.g., FIT, PIT) • Some exceptions are generated by external devices (e.g., CritInt) • Interrupts are automatic control transfers as a result of an exception • Execution of the current program is suspended after the current instruction • Some context info is saved so execution can return to the current program • Execution is transferred to the interrupt handler to service the interrupt • The interrupt handler must be registered • The interrupt must be enabled

36. Hardware Interrupt Inputs • Two external inputs to the IBM PowerPC 405 processor core: • Critical interrupt • External interrupt • Enabled and disabled through the Machine State Register (MSR) • MSR(CE) and MSR(EE) • Default @RESET is disabled • FPGA design adds an interrupt controller for application-specific requirements • Supports 32 interrupts

37. Exceptions and Interrupts Exception Code Entry Point Save State Call Handler HANDLER Restore State Return to Program Registered Handler

38. Exceptions and Interrupts • Exception library function calls support: • void XExc_Init(void); • Initializes vector table, default handlers • void XExc_RegisterHandler (Xuint8 ExceptionId, XExceptionHandler Handler, void *DataPtr); • Allows the registration of a handler • void XExc_RemoveHandler (Xuint8 ExceptionId) • Replaces the current handler with a default handler • void XExc_mEnableExceptions (EnableMask); • Enables Crit, NonCrit interrupts • void XExc_mDisableExceptions (DisableMask); • Disables Crit, NonCrit interrupts

39. thttpd

40. Thttpd • 非常小巧的轻量级web server • 仅仅提供了HTTP/1.1和简单的CGI支持 • thttpd支持多种平台，如FreeBSD, SunOS, Solaris, BSD, Linux, OSF等 • 其资源占用小

41. Web服务器通过调用CGI程序实现和Web浏览器的交互Web服务器通过调用CGI程序实现和Web浏览器的交互 • CGI程序接受Web浏览器发送给Web服务器的信息,进行处理,将响应结果再回送给Web服务器及Web浏览器。 • CGI程序一般完成Web网页中 • 表单(Form)数据的处理、 • 数据库查询 • 实现与传统应用系统的集成等工作。

42. CGI • The Common Gateway Interface • The method by which a web server can get data, and display that data to users via the web • A CGI can be written in any programming language (ex. C/C++, C Shell, Perl, VB)

43. CGI接口标准包括：标准输入、环境变量、标准输出三部分。 • 标准输入 • CGI程序可通过标准输入(stdin)从Web服务器得到输入信息,如Form中的数据,这就是所谓的向CGI程序传递数据的POST方法。 • 环境变量 • 操作系统提供了许多环境变量, 应用程序可以存取它们。Web服务器和CGI接口又另外设置了自己的一些环境变量,用来向CGI程序传递一些重要的参数。CGI的GET方法还通过环境变量QUERY-STRING向CGI程序传递Form中的数据。 • 标准输出 • CGI程序通过标准输出(stdout)将输出信息传送给Web服务器。传送给Web服务器的信息可以用各种格式,通常是以纯文本或者HTML文本的形式

44. CGI 1. HTTP request 2. Call CGI 4. HTTP response 3. CGI program’s response User How does CGI work? Application (on server) Server Web Browser (on client)

45. HTML CGI WEB Page • unsigned char *paramStr; • printf("Content-type: text/html\r\n"); • paramStr=getenv("QUERY_STRING"); • if (paramStr[0]=='x') • { • int seq; • seq = paramStr[6]-'0'; • if (seq<=7) • c = 1 << seq; • else if (seq ==8) • c = 0xff; • else • c = 0x00; • }else • { • int i = 0; • c = 0x00; • for(i = 7; paramStr[i] != '\0';i++) • if (((paramStr[i]-'0')>=0) && ((paramStr[i]-'0')<=7)) • c |= 1 << (paramStr[i]-'0'); • } • <html> • <head><title>X LED Controler</title></head> • <body> • <H2>X-LED Controler</H2> • <H2> • <a href='xledctl.cgi?xflag=0'>Xled0</a><br> • <a href='xledctl.cgi?xflag=1'>Xled1</a><br> • <a href='xledctl.cgi?xflag=2'>Xled2</a><br> • <a href='xledctl.cgi?xflag=3'>Xled3</a><br> • <a href='xledctl.cgi?xflag=4'>Xled4</a><br> • <a href='xledctl.cgi?xflag=5'>Xled5</a><br> • <a href='xledctl.cgi?xflag=6'>Xled6</a><br> • <a href='xledctl.cgi?xflag=7'>Xled7</a><br> • <br> • <a href='xledctl.cgi?xflag=8'>Xled_on</a><br> • <a href='xledctl.cgi?xflag=9'>Xled_off</a><br> • </H2> • input LED light number (0 ~ 7)<br> • <FORM ACTION="xledctl.cgi" METHOD=GET> • <INPUT NAME="input1" TYPE=TEXT SIZE=12><BR> • <INPUT TYPE=SUBMIT VALUE="Commit"> • </FORM><br> • </body> • </html>

46. Project: remote control • Technology • Hardware + OS • Device driver: Led, Switch • Application: CGI, HTML • thttpd&cgi&html.doc • Design Flow • Specification: • Embedded application