tms320dm8148 embedded linux
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TMS320DM8148 Embedded Linux
Overview
Introduction
• Linux Kernel & Components used in embedded system
• Embedded Linux Devices everywhere around us– Android Phones– Digital & Smart TVs– Set Top Boxes
Embedded Hardware Architecture
• Linux Kernel supports 32 & 64 bit architectures– X86 & x86-64– ARM– Power PC– MIPS– SuperH– BlackFin– Microblaze– ColdFire, AVR32
Architecture
Embedded BoardHost PC
Root File System
Linux Kernel & drivers
Boot Loader
C Libraries linux services / commands
ApplicationsCross Compiler
JTAGDebugger
Source Code
Development PC - Compiler
• Code Sourcery ARM Tool Chain– Version 2009-q1– arm-2009q1-203-arm-none-linux-gnueabi-i686-pc-
linux-gnu.tar• https://sourcery.mentor.com/GNUToolchain/release18
02?• Download IA32 GNU/LINUX TAR
• Codesourcery Commercial Edition– Evaluation version of commercial edition
Development PC – Compiler Setup• Uncompress the Compiler Zip File
– tar xvf arm-2009q1-203-arm-none-linux-gnueabi-i686-pc-linux-gnu.tar• Move to /opt/ custom software folder in ubuntu
– mkdir /opt/CodeSourcery– mv arm-2009q1 /opt/CodeSourcery/Sourcery_G++_Lite
• Adding the toolchain path into shell– vi ~/.bashrc
• export PATH=/opt/CodeSourcery/Sourcery_G++_Lite/bin:$PATH– source ~/.bashrc
Development PC - Tools
• JTAG Debugger– This tool is used when new hardware is designed – Used to validate & bring up low level hardware
interfaces ( DDR3, NAND Flash )– XDS 560 V2 System Trace Emulator– XDS 560 PCI Rev D Emulator– Blackhawk USB 560-M Emulator– Spectrum Digital 510 USB Emulator
• Code Composer Studio
Development PC - Console
• Serial Console– Used to get boot up log messages & acts as linux shell
to execute the applications– Default settings : 115200 8N1– Flow Control : None
• Minicom– Text based modem control & terminal emulation utility– PC Serial console – Run “minicom –S” to configure the serial console
Development PC – EZSDK
• EZSDK– Linux EZ Software Development Kit– Linux support based on 2.6.37 Kernel– Quick Start Development– Video / Audio Codecs– DSP accelerated alogrithms– Application Examples – Networked Audio / Video– Qt graphics SDK plugin– OpenMax libraries– Matrix Application Launcher
EZSDK - Architecture
EZSDK - Components
• Linux Kernel 2.6.37• Bootloader• File System• Qt/Webkit application framework• 3D Graphics Support• Flash Tools & Pin Muxing Utility• HDVICP2 Accelerated Codec– H.264 Encode / Decode, MPEG4 Encode / Decode,
MPEG2 Decode & VC1/WMV9 to the video detector
Boot Loader• 1st stage boot loader
– TI 814x BOOT ROM• 2nd & 3rd stage boot loader
– U-Boot Loader– U-Boot-MIN Image
• Prompt TI-MIN#– U-Boot Image
• Prompt TI8148_EVM#
• NOR Boot– Has only two stage bootloader– U-Boot-MIN is not required as NOR is XIP ( eXecute In Place )
Two Stage U-Boot Design• TI814x internal RAM
– 128 KB out of which 18 KB at the end used by ROM Code– Limit of 110KB on the size of U-Boot binary can be transferred to
internal RAM– It needs to setup TEXT_BASE of U-Boot
• 1st stage of U-Boot built with configuration as minimal as possible– Purpose to initialize the necessary peripherals especially DDR
SDRAM– Provides mechanism to load full fledged U-Boot into DDR & then
passed control over it.– Automatic DDR2 & DDR3 selection
U-Boot-MIN
• Different Boot Modes– NAND/SPI Memory Boot
• Header needs to be attached with binary to indicate load address.
• SPI boot requires endian information as well– UART/EMAC/SD Card Peripheral Boot
• No header• Load Address is fixed ( 0x80070000)
– NOR Flash Boot• Header is not required• 1st stage U-Boot is not required, as it is eXecute In Place (XIP)
U-Boot Loader• 2nd stage of U-Boot
– Supports saving environment variables into • NAND / SPI Flash• SD Card• NOR Flash
– Storage media will be configured before building of 2nd stage U-Boot• Supported with Storage Media
– Write & Read files ( like boot, kernel, filesystem images ) back from storage media
– Loads kernel image & execute the same• Loads from Storage• Loads from TFTP server using Ethernet
U-Boot Loader – Kernel Boot• Boot from NAND
– nand read.i 0x81000000 280000 500000– bootm 0x81000000
• Boot from SPI– sf read 0x81000000 0x42000 0x200000– bootm 0x81000000
• Boot from NOR– cp.w 0x08060000 0x81000000 0x200000– bootm 0x81000000
• Boot over Network– tftp 0x81000000 uImage– bootm 0x81000000
Linux Kernel
• Unix Like computer operating system kernel• Default kernel configuration– ti8148_evm_defconfig
• Kernel Image format– uImage – U-Bootloader based image– mkimage utility used to create linux kernel image
Linux Kernel
• Manages all the hardware peripherals like CPU, Memory, IO
• Provides an interface for user space application & libraries to access hardware interfaces
• Manages multiple user access– Provides a hardware interface access for multiple
user application access
Linux Kernel – Block DiagramMemory
Management block - HW MMU
Scheduler & TaskManagement
File System
Device Drivers
Low Level CPU initialization
Network Stack
DeviceTree
HardwareDescription
Linux Kernel – Device Drivers• Power Management• GPIO Driver• EDMA3 Driver• Audio Driver• SATA Driver• USB Driver• SD / MMC Card Driver• Ethernet Switch Driver• VPSS Video Driver
– VPSS Video Capture Driver• HDMI Driver• McSPI Driver• PCI Express Root Complex Driver• PCI Express End Point Driver• Touch Screen Driver• Watchdog Timer
File System
• Root File System– Ramdisk – Cramfs– Ext 2,3,4– FAT
• Pseudo file system– Proc– Sysfs– Dev Filesystem
Root File System Structure• bin• boot• dev• etc• lib• lost+found• misc• mnt• net• opt• proc• root• sbin• tmp• usr• Var
