Embedded Linux Development on ARM Processor

1
Embedded Linux Development on ARM Processor

• Training by
• Mr. Siriroj Jungthawan
• Embedded Systems Engineer
• Design Gateway Co.,Ltd.

2
Agenda

• Part 1
• Embedded System
• Embedded Linux
• Software and Tool for Embedded Linux
• Part 2
• JAMP-II Board
• Setup tools and Develop

3
Embedded System
4
Embedded System
Store Program
Control System
System Function
5
Basic Embedded System
6
Advanced Embedded System
7
Operating System
Process
8
Embedded OS sourcing trends
Ref. www.linuxdevices.com
9
Linux Advantage

• Free license
• Open-source
• Robust TCP/IP stack
• Large community
• Support many processor architectures (32/64 bit)
• i.e. ARM, MIPS, PowerPC, x86, v850, SH

10
Embedded Processor Trends
Ref. www.linuxdevices.com
11
Embedded Linux
12
Embedded Linux

• Supported from manufacturers to ported Linux to
  their microprocessor
• Freescale, Atmel, Cirrus Logic
• Multi-Processing
• Utilize small memory and storage
• Highly customizable
• Development based on C Language

13
Embedded Linux Type

• Kernel.org Original Linux kernel
• uCLinux No MMU Architecture
• RTLinux Real Time Scheduler
• Linux Distributor
• Montavista, TimeSys, Koan, Wind River

14
Embedded Linux OS sourcing trends
Ref. www.linuxdevices.com
15
Embedded Linux System
SD card
USB
IDE
VGA
CF
Flash
SD-RAM
Serial
FPGA
Audio
CPU
Ethernet
PS2
16
Software and Tool for Embedded Linux
17
Embedded Linux Components
18
Compiler
19
Compile Step
20
Compiler (Toolchain)

• Compiler types
• Native Compiler same processor architecture
• i.e. gcc, tcc, sdcc
• Cross Compiler different processor architecture
  
• i.e. arm-linux-gcc, ppc-linux-gcc ,
  mipsel-linux-gcc
• arch-system-gcc
• Steps to build compiler and other tools
• Download source code
• Configure (select architecture)
• Compile source code

21
Source code for Compiler

• GNU binary utilities (binutils)
• GNU compiler collection (gcc)
• C library
• Glibc for Linux
• Uclibc for embedded Linux
• Newlib for embedded system
• Linux Kernel Headers (2.2, 2.4, 2.6)
• GNU debugger (gdb)

22
Boot Loader
23
Boot Loader

• Low level system setup (CPU, Serial)
• Detect Peripheral Device (Flash)
• Configured by command line
• Support protocol for transfer data
• Serial X-modem, Y-modem, Kermit
• Ethernet TFTP

24
Boot Step

• ROM boot
• Default system setup
• i.e. CPU speed, device address
• Load data from flash to SDRAM
• Run data from SDRAM

ROM

• Boot loader
• Setup CPU speed, Bus speed, Bus size
• Detect, Setup and test Peripheral Device
• Run boot script or console mode

25
Console Feature

• Set parameter and Boot script
• Read/Write/Compare data to RAM
• Copy data with RAM and Flash
• Download data from Serial, Ethernet
• Test Image

26
Boot Loader

• Popular Bootloader for Embedded Linux
• Redboot, U-boot
• Popular supported architectures
• x86(PC), PowerPC(Mac), ARM and MIPS

27
Linux Kernel
28
Linux Kernel
29
Kernel Module

• For adding more feature to Linux Kernel
• Support new device driver
• Support new file system type
• Support new protocol
• Kernel module operation
• insmod insert a module into Linux Kernel
• rmmod remove a module from Linux Kernel
• lsmod show the status of modules in Linux
  Kernel
• modprobe (Ref. /etc/modprobe.conf)

30
Root File System
31
Root File System RootFS

• RootFS Area for storing all Linux data
• Command (ls, mv, rm)
• Device node (/dev/console, /dev/tty)
• Configure File (.conf)
• library (.a, .so)
• Kernel module object (.ko)
• Symbolic link (Shortcut on Windows)
• Application (Firefox, vsFTPd)
• Note File type can checked by Command file

32
Linux RootFS Hierarchy
33
Directory of Root File System

• / Root node
• /bin Essential command binaries
• /dev Device node
• /etc Host-specific system configuration
• /home User home directories (optional)
• /lib Essential shared libraries and kernel
  modules
• /media Mount point for removable media
• /mnt Mount point for mounting a filesystem
  temporarily
• /proc Mount point for Kernel and process
  information virtual filesystem
• /root Home directory for the root user (optional)
• /sbin Essential system binaries
• /sys Mount point sysfs for exporting kernel
  objects infrastructure
• /tmp Temporary files
• /usr Secondary hierarchy
• /var Variable data

34
File System Types

• Structure for Data on Storage
• MS-DOS(FAT), FAT32, NTFS, ISO9660
• File systems for Embedded Linux
• EXT2 The Second Extended File system, Typical
  file system in Linux
• EXT3 The Third Extended File system, the
  ext2 file system enhanced with journaling
  capabilities
• JFFS Journaling Flash File System used for
  Flash memory (MTD)
• NFS Network file system, used for
  network drive from other host

35
Media for Root File System

• Storage (EXT2, EXT3)
• Hard disk, Ram disk, USB Flash drive, MMC/SD card
• Memory Technology Devices MTD (JFFS/JFFS2)
• NOR Flash, NAND Flash, OneNAND Flash, SPI Flash
• Network (NFS)
• Network Device from NFS server on other PC

36
Device Driver
37
Device Driver
38
Device Control

• Bus Interface in system
• Bus Interface PCI, IDE, SCSI, PCMCIA
• Serial Bus Interface 1-wire, I2C, SPI, USB
• Device in system
• Port serial port, parallel port
• User Interface Keyboard, Mouse, Joystick, touch
  screen
• Storage HDD, MMC/SD, Flash (MTD)
• Network Ethernet, Wireless LAN, Bluetooth
• Sound (OSS, ALSA)
• Graphics (Frame Buffer)
• Etc Real Time Clock, Watchdog, GPIO, ADC, PWM

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Device Class

• Character Devices
• Serial port, Frame Buffer, Sound
• Block Devices
• Hard disk, Flash memory, CDROM
• Network Devices
• Ethernet, Wireless LAN

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How to access device

• Application must access device through device
  node
• /dev/ttyS0
• /dev/sda1
• Access device node by File operation
• open(), read(), write(), close(), ioctl()

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Device node

• Device type
• chr_dev (character devices)
• blk_dev (block devices)
• Device number
• Major number 1-239, 240-254 (local/experimental
  use), 255 (reserved)
• Minor number 0-255
• Device node Example
• /dev/sda1, /dev/ttyS0 , /dev/ttyS1, /dev/zero
• brw-r----- 1 root root 8, 1 Sep 6 2007
  sda1
• crw-rw---- 1 root root 4, 64 Sep 6 2007
  ttyS0
• crw-rw---- 1 root root 4, 65 Sep 6 2007
  ttyS1
• crw-rw-rw- 1 root root 1, 5 Sep 6 2007
  zero
• Ref. Kernel Source/Documentation/devices.txt

42
Application
43
Application

• Developed by C/C language
• Standard C library
• File Operation
• Network Operation
• Device Access Operation
• Thread, Signal (interrupt software)
• Inter Process Communication IPC
• Other Library
• libjpeg, libz, libfreetype

44
Library Executed Type

• Library Type
• Static library Archive Object (libpng.a)
• ar rcs libpng.a png.o pngerror.o pngmem.o
• Share library Share Object (libpng.so)
• Executed Type
• statically linked (gcc -static)
• dynamically linked

45
QA Part 1
46
JAMP-II Board
47
JAMP-II Box Content

• JAMP-II board
• Serial cable
• LAN cross cable
• Adapter 5 Volt
• Document and SDK CD
• VMware DVD
• Registration card

48
Embedded Linux System
SD card
USB
IDE
VGA
CF
Flash
SD-RAM
Serial
FPGA
Audio
CPU
Ethernet
PS2
49
Board Overview

• 180 MHz ARM920T core
• 64MB SD RAM
• 4 MB Parallel Flash
• 1 Mb EEPROM
• 3 Serial port (support RS485)
• 1 USB 2.0 Full speed host
• 1 USB 2.0 Full speed device
• 1 MMC/SD card socket
• 1 CF socket
• 1 ATA IDE 40pin port
• 10/100 Ethernet
• Audio Input/output
• FPGA Spartan 3E 500K gates
• 4 Mb Serial Flash
• 2 port PS2
• 1 port VGA

50
Serial Console Setup
Setup 115200 8N1 non-flow
51
Hardware Setup
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Course Overview
56
Course Overview

• Setup OS and Service
• Setup SDK
• Setup Firmware First-Time
• Setup, Build and Update U-boot
• Setup, Build and Update Linux Kernel
• Setup, Build and Update RootFS
• Update PROM FPGA

57
Setup OS and Service
58
Setup OS and Service

• Setup OS (Fedora Core 4)
• Setup Network (Ethernet)
• Setup Service (Daemon)
• sshd service (Secure Shall)
• vsftpd service (File Transfer Protocol)
• nfs service (Network File System)
• samba service (Window Share File)
• tftp service (Trivial File Transfer Protocol)

59
Setup OS (Fedora Core 4)

• Install Fedora Core 4 on PC
• Installation type workstation
• Package Installation Default Customize ..
• Package Group Selection Server
• Server Configuration Tools
• Windows File Server
• FTP Server
• Legacy Network Server ? tftp-server

60
Setup OS (Fedora Core 4)
Setup from CD/DVD
61
Setup OS (Fedora Core 4)
Select Workstation
62
Setup OS (Fedora Core 4)
Select Costomize software package..
63
Setup OS (Fedora Core 4)
VMplayer play VMimage
64
Setup OS (Fedora Core 4)
VMplayer Login root/dg, Password abc123
65
Setup Network (Ethernet)
setup
66
Setup Network (Ethernet)
Select Network Configufation ? Ethernet
67
Setup Network (Ethernet)
service network restart
68
Setup Service (daemon)
setup
69
Setup Service (daemon)
select System services
70
Setup Service (daemon)
service sshd, vsftpd, nfs, smb xinetd status
71
Setup Service (daemon)
Transfer data by vsFTPd service
72
Setup Service (daemon)
Transfer data by Samba service
73
JAMP-II Development Step
74
Setup SDK
75
Setup SDK

• Setup SDK
• Install cross-compiler
• Install dg-arm-linux
• Setup Source code
• Compiler Source code
• Move Firmware JAMP-II into directory ./firmware
• Export Path of cross-compiler

76
./setup
77
JAMP-II Firmware

• loader.bin (First stage boot on ram)
• boot.bin (First stage boot on flash)
• u-boot.bin and u-boot.gz (Boot loader)
• zImage (Linux kernel)
• initrd.gz (image rootfs on SD-RAM)
• root_jffs2.img (image rootfs on nor flash)
• promdata.bin (configure FPGA on SPI flash)
• Firmware in path ./firmware

78
vim .bash_profile (/root/, /home/dg/)
79
Setup Firmware First-Time
80
Setup Firmware first-Time

• Switch Boot mode
• Set jumper (J30) pin 1-2
• Push reset button
• Load Firmware by 1K X-modem protocol on serial
• Load loader.bin
• Load u-boot.bin
• Flash Firmware by Kermit on serial or TFTP on
  Ethernet
• Flash boot.bin
• Flash u-boot.gz

81
JAMP-II Development Step
82
Setup and Build U-boot
83
Setup and Build U-boot

• Clean source
• make mrproper
• Select Platform
• make jamp2_config
• Built U-boot
• make

84
make jamp2_config
85
gzip -9 -c u-boot.bin gt u-boot.gz
86
Update U-boot
87
Update U-boot

• Unprotect and erase area flash memory
• U-Bootgt protect off 10010000 1002ffff
• U-Bootgt erase 10010000 1002ffff
• Fill memory area
• U-Bootgt mw.b 20008000 ff 20000
• Download u-boot.gz into board
• U-Bootgt tftp 20008000 u-boot.gz
• Copy from SD-RAM to flash memory
• U-Bootgt cp.b 20008000 10010000 20000

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Setup and Build Kernel
90
Setup and Build Kernel

• Configure Linux Kernel
• Process management multitask
• Memory management virsual memory, swap
• File system ext2, ext3, vfat, jffs2, nfs
• Device control flash, serial, audio, Ethernet
• Networking TCP/IP, IPv4, IPv6, IPX
• Kernel Command Line
• Option for kernel module
• ltgt, built in to kernel. (press y)
• lt gt, remove it. (press n)
• ltMgt make it to module. (press m)

91
Setup and Build Kernel

• Show make option of Linux Kernel
• make help
• Load Default Configure JAMPII
• make at91rm9200dk_defconfig
• Configure Linux Kernel
• make menuconfig
• Compile Linux Kernel
• make
• Compile Kernel Module
• make modules_install INSTALL_MOD_PATH./

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make at91rm9200dk_defconfig
93
make menuconfig
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make
96
cp arch/arm/boot/zImage /tftpboot/
97
make modules_install INSTALL_MOD_PATH./
98
Update Linux Kernel
99
Update Linux Kernel

• Erase area flash memory
• U-Bootgt erase 10030000 1016ffff
• Fill memory area
• U-Bootgt mw.b 20008000 ff 140000
• Download zImage into board
• U-Bootgt tftp 20008000 zImage
• Copy from SD-RAM to flash memory
• U-Bootgt cp.b 20008000 10030000 140000

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101
Setup and Build RootFS
102
Setup and Build RootFS

• Setup and Build RootFS
• Skeleton of RootFS
• Binary command (Busybox)
• Configure file (text file)
• busybox is tools for build command
• buildroot is tools for build root file system

103
Build RootFS on Ramdisk

• Create raw data
• dd if/dev/zero ofinitrd bs1k count4k
• Create file system into raw data
• mkfs.ext2 -b 1024 -F initrd
• Create node and mount to raw data
• mkdir ./node_initrd
• mount t ext2 o loop initrd ./node_initrd
• Copy data from rootfs path into node of initrd
• cp R ROOTFS ./node_initrd
• Un-mount from raw data
• unmount ./node_initrd
• Compress raw data
• gzip -9 c initrd gt initrd.gz
• Initrd initial ramdisk

104
Build RootFS on MTD

• Create RootFS type jffs2
• mkfs.jffs2 -e 0x10000 -o rootfs.jffs2 -r
  ROOTFS
• -e erase size of flash
• -o output to file name
• -r node of RootFS

105
Build RootFS on NFS

• Configure NFS drive on PC
• Edit /etc/exports
• add ROOTFS (rw,sync,no_root_squash)
• Restart NFS service for check configure
• service nfs restart
• Create node and Test mount NFS drive
• mkdir ./node_nfs
• mount o nolock SERVER_IPROOTFS ./node_nfs
• Un-mount NFS drive
• umount ./node_nfs

106
Update RootFS
107
Update RootFS

• Erase area flash memory
• U-Bootgt erase 10170000 103fffff
• Fill memory area
• U-Bootgt mw.b 20410000 ff 290000
• Download initrd.gz into board
• U-Bootgt tftp 20410000 initrd.gz
• Copy from SD-RAM to flash memory
• U-Bootgt cp.b 20410000 10170000 1c0000

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Update PROM FPGA
110
Update PROM FPGA

• Unprotect area flash memory
• U-Bootgt protect off D0000000 D0083FFF
• Fill memory area
• U-Bootgt mw.b 20008000 ff 84000
• Download promdata.bin into board
• U-Bootgt tftp 20008000 promdata.bin
• Copy from SD-RAM to flash memory
• U-Bootgt cp.b 20008000 D0000000 84000

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QA Part 2
113
Embedded Linux Development on ARM Processor

• Training by
• Mr. Siriroj Jungthawan
• Embedded Systems Engineer
• Design Gateway Co.,Ltd.

114
Agenda

• Part 1
• Application Development
• Makefile
• Access File Programming
• Network Programming
• Access Device Programming
• Part 2
• Device Driver Development
• Character Device Driver

115
JAMP-II Development Step
116
Application Development
117
Build Application

• Source code
• Source file (.c, .cpp)
• Header file (.h, .hpp)
• Library
• Static Library (.o, .a)
• Dynamic Library (.so)
• Makefile
• Application (Execute File)
• Hint user can check dynamic library of
  Application by command ldd

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Makefile
122
Makefile for Application

• Comment ()
• comment line
• Macro
• CROSS_COMPILE arm-linux-
• CC (CROSS_COMPILE)gcc
• Target
• hello hello.o
• (CC) -o hello hello.o

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Makefile for Application

• CROSS arm-linux-
• CC (CROSS)gcc
• all hello
• compile application
• hello hello.o
• (CC) -o hello hello.o
• hello.o hello.c
• (CC) -c hello.c
• clean application
• clean
• rm .o hello

124
Access File Programming
125
Access File Programming

• Example Access_File
• include ltstdio.hgt
• FILE fopen(const char path, const char mode)
• size_t fread(void ptr, size_t size, size_t
  nmemb, FILE stream)
• size_t fwrite(const void ptr, size_t size,
  size_t nmemb, FILE stream)
• int fprintf(FILE stream, const char format,
  ...)
• int fscanf(FILE stream, const char format,
  ...)
• int fflush(FILE stream)
• int fclose(FILE stream)

126
Network Programming
127
Network Programming

• Example Server_client
• include ltsys/socket.hgt
• include ltnetinet/in.hgt
• include ltarpa/inet.hgt
• int socket(int domain, int type, int protocol)
• int bind(int sockfd, struct sockaddr my_addr,
  socklen_t addrlen)
• int listen(int sockfd, int backlog)
• int accept(int sockfd, struct sockaddr
  client_addr, socklen_t addrlen)
• int connect(int sockfd, const struct sockaddr
  server_addr, socklen_t addrlen)
• ssize_t recv(int sockfd, void buf, size_t len,
  int flags)
• ssize_t send(int sockfd, const void buf, size_t
  len, int flags)
• int shutdown(int sockfd, int how)

128
Access Device Programming
129
Serial Port Programming

• Example Serial_port
• include ltfcntl.hgt
• include ltunistd.hgt
• include ltsys/ioctl.hgt
• include lttermios.hgt
• int open(const char pathname, int flags)
• ssize_t read(int fd, void buf, size_t count)
• ssize_t write(int fd, const void buf, size_t
  count)
• int ioctl(int fd, int request, ...)
• int close(int fd)
• int tcgetattr(int fd, struct termios termios_p)
• int tcsetattr(int fd, int optional_actions,
  struct termios termios_p)

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QA Part 1
131
Device Driver Development
132
Building Device Driver

• Kernel Source Path
• ./dg-arm-linux-1.0.3/linux-2.6.16.16
• Source code
• Source file (.c, .cpp)
• Header file (.h, .hpp)
• Makefile
• Kernel module (.ko)
• Device Node
• mknod /dev/memop c 245 0

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Basic Kernel module

• include ltlinux/init.hgt
• include ltlinux/module.hgt
• int (init)(void)
• void (exit)(void)
• module_init(init)
• module_exit(exit)
• Ref .. ./basic_dev/hello_module.ko

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Character Device Driver
138
Character Devices

• include ltlinux/fs.hgt
• include ltlinux/cdev.hgt
• define MAJOR(dev) ((unsigned int) ((dev) gtgt
  MINORBITS))
• define MINOR(dev) ((unsigned int) ((dev)
  MINORMASK))
• define MKDEV(ma,mi) (((ma) ltlt MINORBITS) (mi))
• int alloc_chrdev_region(dev_t , unsigned,
  unsigned, const char )
• int register_chrdev_region(dev_t, unsigned, const
  char )
• void unregister_chrdev_region(dev_t, unsigned)
• void cdev_init(struct cdev , struct
  file_operations )
• int cdev_add(struct cdev , dev_t, unsigned)
• void cdev_del(struct cdev )

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Character Devices(cont.)

• struct file_operations
• struct module owner
• ssize_t (read) (struct file , char __user ,
  size_t, loff_t )
• ssize_t (write) (struct file , const char
  __user , size_t, loff_t )
• int (ioctl) (struct inode , struct file ,
  unsigned int, unsigned long)
• int (mmap) (struct file , struct
  vm_area_struct )
• int (open) (struct inode , struct file )
• int (release) (struct inode , struct file )
• ...

140
Communication with hardware
Allocation and mapping Kernel space to User space
Allocation and mapping Hardware to Kernel space
141
Communication with hardware

• I/O Memory Allocation
• struct resource request_mem_region (unsigned
  long start, unsigned long len, const char name)
• void release_mem_region (unsigned long start,
  unsigned long len)
• int check_mem_region (unsigned long start,
  unsigned long len)
• I/O Memory Mapping
• void ioremap (unsigned long phys_addr, unsigned
  long size)
• void ioremap_nocache (unsigned long phys_addr,
  unsigned long size)
• void iounmap (void addr)

142
Communication with hardware

• Accessing I/O Memory
• unsigned char readb(void addr)
• unsigned short readw(void addr)
• unsigned long readl(void addr)
• void writeb(unsigned char data, void addr)
• void writew(unsigned short data, void addr)
• void writel(unsigned long data, void addr)
• Accessing I/O Memory (String Operation)
• void readsb(void addr, void data, int len)
• void readsw(void addr, void data, int len)
• void readsl(void addr, void data, int len)
• void writesb(void addr, const void data, int
  len)
• void writesw(void addr, const void data, int
  len)
• void writesl(void addr, const void data, int
  len)

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Access Data betweenKernel space and User space

• Open/Close
• int open(const char pathname, int flags)
• int close(int fd)
• Read/Write
• ssize_t read(int fd, void buf, size_t count)
• ssize_t write(int fd, const void buf, size_t
  count)
• Control device
• int ioctl(int fd, int request, void argp)
• Memory map
• void mmap(void start, size_t length, int prot
  , int flags, int fd, off_t offset)
• int munmap(void start, size_t length)

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QA Part 2
147
Welcome to Embedded Linux World
Thank you

• siriroj_at_design-gateway.com

148
Appendix
149
Toolchain Cross-compiler

• Shell-Script for built GCC
• Crosstool (GNU C Library glibc)
• http//www.kegel.com/crosstool/download
• uClibc (micro C library uclibc)
• http//www.uclibc.org/downloads
• Binary
• Gnutools (New C library Newlib)
• http//ecos.sourceware.org/mirror.html

150
Boot Loader Link

• Red-boot
• original
• http//ecos.sourceware.org/mirror.html
• U-boot
• original
• http//www.denx.de/wiki/UBoot/WebHome

151
Linux Kernel Link

• Linux kernel
• original
• http//www.kernel.org/pub/linux/kernel/v2.6/
• patch for JAMP-II board
• http//www.design-gateway.com/forum/viewforum.php
  ?f24
• patch for at91rm9200 Other board
• http//maxim.org.za/at91_26.html

152
Device Driver

• Ref.
• http//lwn.net/Kernel/LDD3/

153
Application

• Ref.
• Beginning Linux Programming
• Professional Linux Programming
• Advanced Linux Programming
• http//www.advancedlinuxprogramming.com/downloads
  .html