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Tizen Bootup

Tizen Bootup. Contents. Bootloader overview Tizen U-boot Tizen Systemd Platform bootup. Bootloader. Tizen bootup overview. Bootloader Pass Machine ID and the boot arguments to kernel. Power on. ROM code. Booting device. Bootloader. Kernel. Platform. What is bootloader.

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Tizen Bootup

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  1. Tizen Bootup

  2. Contents • Bootloader overview • Tizen U-boot • Tizen Systemd • Platform bootup

  3. Bootloader

  4. Tizen bootup overview • Bootloader • Pass Machine ID and the boot arguments to kernel Power on ROM code Booting device Bootloader Kernel Platform

  5. What is bootloader • What is boot loader ? • A boot loader is the first program which executes (before the main program i.e. kernel ) whenever a system is initialized • A boot loader is a computer program that loads the main program (i.e. operating system, kernel ) for the board after completion of the self-tests • Why boot loader is needed ? • Gives a development environment • Saves cost of flash writers • Give flexibility to load any operating system

  6. Types of bootloader • What are different types of boot loaders ? • Boot-ROM ( or Pre-Boot Loader) • Small code which loads First stage boot loader • First Stage Boot Loader • Small Piece of code that initialize the NAND/MMC & DRAM controller. • Second Stage Boot Loader • Primary function of the second-stage boot loader is to Loading the kernel into RAM or jumping directly to the start of the kernel. OS Kernel Pre-Bootloader First-Stage Bootloader Second-Stage Bootloader

  7. U-boot loading process Exynos4412 DRAM controller DRAM Cortex-A9 Booting Device (NAND, MMC, SD, USB) eSSD controller Internal ROM 1 iROM code NAND controller 1st BL 2nd BL SD/MMC controller 2 Internal SRAM OS 3 UART/USB

  8. U-boot loading process • BL0; iRom code (boot-rom or pre-boot loader) • Simple platform independent code, stored in internal ROM • Initialize basic functions (clock, stack, heap, etc) • Load first stage boot loader (from booting device to internal SRAM) • BL1; first boot loader • Simple platform independent code, stored in external memory(booting device) • Load second boot loader • Initialize NAND/MMC and DRAM controller • BL2; second boot loader • Platform dependent complex code, stored in external memory • Initialize clock, UART • Load OS image from booting device toDRAM • Jump to operating system

  9. U-boot directory structure /u-boot /u-boot Machine/arch independent API Example code for standalone applications examples api Architecture specific files Filesystem code (cramfs, ext2, jffs2, etc.) arch fs Board dependent files Header files board include Misc architecture independent functions Files generic to all architectures common lib Code for disk drive partition handling Networking code disk net Documentation Power on self test doc post Commonly used device drivers drivers Real time clock drivers rtc tools Tools to build S-Record or U-boot images

  10. U-boot code sequence • Disable all interrupts • Copy any initialized data from ROM to RAM • Zero the uninitialized data area • Allocate space for and initialize the stack • Initialize the processor’s stack pointer • Create and initialize the heap • Execute the initializers for all global data • Enable interrupts • Call main loop

  11. cpu_init_crit Invalidate and disable Instruction & data Cache Disable MMU U-boot code sequence Reset CPU and Hardwarecpu/armv7/start.S _start() Setup SP for Early Board Setup Environment (ASM->C) Disable IRQ &FIQ. Switch to supervisor mode cpu/armv7/start.Sreset() General Relocation arm/lib/crt0.S_main() cpu/armv7/start.Srelocate_code() Early Board Setup arm/lib/crt0.Sboard_init_f() Low Level Initialization Copy Binary to RAM Fix Relocation Calculate Addresses (SP, Dest, GD) for Relocation Clear BSS Setup SP for Common Board Setup Setup GD and JUMP toFinal Board Setup lowlevel_init arm/lib/crt0.Sboard_init_r() board/samsung/lowlevel_init.Slowlevel_init() Jump into main loop

  12. U-boot code sequence • _start() /* Entry point function */ • reset() /* Reset CPU configurations */ • save_boot_params() /* Save boot parameters */ • Disable the FIQ & IRQ • Switch to supervisor mode • cpu_init_crit() • Invalidate I, D Cache • Disable I cache if CONFIG_SYS_ICACHE_OFF • Disable MMU • lowlevel_init() • _main() /* setup initial stack & global data. And jump to C routine for board initialization */

  13. U-boot code sequence • board_init_f() • arch_cpu_init // basic arch cpu dependent setup • board_early_init_f // early board initialization, UART pin setting • timer_init // initialize timer • env_init // initialize mmc/sdcard environment • init_baudrate // initialize baudrate settings • serial_init // serial communication setup • console_init_f // stage 1 init of console, configure console from console.c • display_banner // say that we are here, print u-boot banner • print_cpuinfo // display cpu info • checkboard // display board info • init_func_i2c // initialize I2C • dram_init // configure available RAM backs • arm_pci_init

  14. U-boot code sequence • board_init_r() • board_init // setup chipselects specific configuration • logbuff_init_ptrs // initialize default log level • mem_malloc_init // configure malloc area • nand_init mmc_init // initialize flash/mmc • env_relocate // relocate environment or set NULL • stdio_init // setup stdio ready for use • api_init // initialize API • console_init_r // fully init console as a device • arch_misc_init // miscellaneous arch dependent initialization • misc_init_r // miscellaneous platform dependent initialization • interrupt_init // set up exceptions • enable_interrupts // enable exceptions • board_late_init // board late initialization • eth_initialize // setup ethernet • main_loop // jump to main loop & waiting for commands from console

  15. U-boot code sequence main_loop() Wait for 3 seconds Key pressed within 3 seconds Input command Command_mode() Autoboot_mode() boot() loads() tftpboot() flash() Jump to kernel image address

  16. Loading through U-boot SDRAM Reset CPU Kernel Root File-System Booting device Bootloader uboot Bootloader uboot Kernel Image Optional compressed Root File System

  17. Loading through U-boot • Packing uImage • When the kernel is complied, mkimage attaches image_header to kernel image • Unpacking uImage • Magin number  CRC check  decompress  get board information  kernel booting #define IH_MAGIC    0x27051956 /* Image Magic Number     */ #define IH_NMLEN    32 /* Image Name Length     */ typedef struct image_header { uint32_t    ih_magic; /* Image Header Magic Number */ uint32_t    ih_hcrc; /* Image Header CRC Checksum */ uint32_t    ih_time; /* Image Creation Timestamp  */ uint32_t    ih_size; /* Image Data Size    */ uint32_t    ih_load; /* Data Load  Address   */ uint32_t    ih_ep; /* Entry Point Address       */ uint32_t    ih_dcrc; /* Image Data CRC Checksum   */ uint8_t     ih_os; /* Operating System         */ uint8_t     ih_arch; /* CPU architecture         */ uint8_t     ih_type; /* Image Type             */ uint8_t     ih_comp; /* Compression Type     */ uint8_t     ih_name[IH_NMLEN]; /* Image Name     */ } image_header_t;

  18. start_kernel • Architecture dependent setup • setup_arch() [/arch/arm/kernel/setup.c] • Exception(or trap)initialization • trap_init() [/arch/arm/kernel/trap.c] • Interruptinitialization • init_IRQ() [/arch/arm/kernel/irq.c] • sotfirq_init() [/kernel/sotfirq.c] • Schedulerinitialization • sched_init() [/kernel/sched.c] • Timerinitialization • time_init() [/arch/XXX/kernel/time.c] • Consoleinitialization • console_init() [/driver/char/tty_io.c] • Moduleinitialization • init_module() [/kernel/module.c]

  19. start_kernel • Memory &System initialization , Cache &Buffer initialization , File system initialization • kmem_cache_init() [/mm/slab.c] • mem_init() [/arch/a,r/mm/init.c] • kmem_cache_size() [/mm/slab.c] • fork_init() [/kernel/fork.c] • proc_caches_init() [/kernel/fork.c] • vfs_caches_init() [/fs/dcache.c] • buffer_init() [/fs/buffer.c] • page_cache_init() [/mm/filemap.c] • signals_init() [/kernel/signal.c] • proc_root_init() [/fs/proc/root.c] • ipc_init() [/ipc/util.c] • init process creation • rest_init() [/init/main.c]

  20. systemd

  21. What is systemd? • Sysvinit • userspacelaunch (PID 1) • Only one process at a time running • Simply starting the system and then going to sleep until the next reboot • Systemd • Default init in Fedora 15 and later Leonard Poettering (2009) • improve the software framework for expressing dependencies • allow more processing to be done concurrently or in parallel during system booting • reduce the computational overhead of the shell.

  22. What is systemd? • Systemd in Tizen • System and service manager for tizen systemd • Ver. 43 (download http://www.freedesktop.org/software/systemd/) • Parallelizes service execution • Socket and D-Bus activation for starting services and daemon • on-demand starting of daemons • Managing the service processes as a group using Linux cgroup • Supporting automount points • Snapshotting and restoring of services

  23. systemd architecture

  24. systemd architecture • systemd Utility • monitoring and controlling systemd itself and its services • 'systemctl' developers can query or send control commend to the systemd service manager • 'systemd-journalctl' utility to see log message • systemd target • Tizen boot-up process is split up in various discrete steps and each step are grouped its unit using 'Target' unit to synchronize point • The boot-up process is highly parallelized in each target so that the order in which specific target units are reached in not deterministic • systemd daemon • system and service manager for Tizen platform • acts as init system • 'systemd' daemonruns as user session with '--user' option • 'systemd-journald' is a system service that collects and stores log data from the Kernel, from user processes via syslog or STDOUT/STDERR

  25. systemd architecture • systemd core • manages all units such as service, socket, mount and so on, stores all log data. • controlled by using systemd utility like 'systemctl' • systemd library & Linux Kernel • systemd requires to enable 'cgroup' and 'autofs' option in Kernel configuration • It also depends on dbus and some libraries such as libnotify, libudev

  26. Platform bootup – sysinit.target • Early boot-up scripts • Most of file system are mounted and systemd related daemons are launched Kernel dev-hugepages.mount dev-mqueue.mount proc-sys-fs-binfmt_misc.automount sys-fs-fuse-connections.mount sys-kernel-config.mount sys-kernel-debug.mount sys-kernel-security.mount systemd-ask-password-console.path systemd-binfmt.service systemd-journald.service systemd-modules-load.service systemd-random-seed-load.service systemd-readahead-collect.service systemd-readahead-replay.service systemd-sysctl.service systemd-tmpfiles-setup.service local-fs.target sysinit.target -.mount boot.mount csa.mount fsck-root.service media.mount opt-usr.mount opt.mount remount-rootfs.service resize2fs-root.service systemd-remount-api-vfs.service var-run.mount basic.target bootmode.target multi-user.target graphical.target socket.target dbus.socket systemd-initctl.socket systemd-journald.socket systemd-shutdownd.socket telnetd.socket udev-control.socket udev-kernel.socket swap.target

  27. Platform bootup – basic.target • Basic boot-up • All necessary initialization for general purpose daemons are completed Kernel sysinit.target opt-var-kdb-db-libsqlfs.service opt-var-kdb-db-smack-labels.service smack-default-labeling.service systemd-tmpfiles-clean.timer tizen-debug-level.service udev-trigger.service udev.service vconf-setup.service basic.target bootmode.target multi-user.target graphical.target

  28. Platform bootup – bootmote.target • Select boot mode • If kernel boot parameter has ‘charger_detect_boot’, the platform boots up as charging mode Kernel sysinit.target basic.target bootmode.target bootmode-charging.service bootmode-graphical.service multi-user.target graphical.target

  29. Platform bootup – multi-user.target • Setup a multi-user system which is non-graphical support • Launching platform infrastructure daemons (such as dbus, power manager, gps manager, telephony daemon, WRT security daemon, media server, systemd-related daemons) Kernel alarm-server.service avsystem.service bluetooth-address.service bluetooth-frwk-service.service bluetooth.service dbus.service dlog-main.service dlog-radio.service getty.target gps-manager.service media-server.service nfc-manager.service power-manager.service pulseaudio.service secure-storage.service sensor-framework.service system-server.service systemd-ask-password-wall.path systemd-logind.service systemd-user-sessions.service telephony.service sysinit.target basic.target bootmode.target multi-user.target graphical.target

  30. Platform bootup – graphical.target • Setup a graphical environment • System user session for app privilege daemons such as Enlightenment (window manager) • Special target for middleware & mobile service Kernel ac.service launchpad-reload@app.service user-session@app.service wrt_launchpad_daemon@app.service sysinit.target basic.target xorg.target tizen-mobile-session.target bootmode.target xorg.service wrt-preinstall-widgets.service multi-user.target core-efl.target boot-animation.service cbhm.service e17.service indicator.service osp-app-service.service quickpanel.service scim.service starter.path xmodmap.service xrdb.service graphical.target tizen-middleware.target calendar.service contacts-service.service download-provider.service email.service msg-service.service pushd.service sound-server.service

  31. Systemd parsing

  32. Platform bootup • systemd • Control is moved from initramfs tosystemd of Tizen platform • Run hardware init and fs mount, etc services • Bootup process run several units (.target) • Different target can be run in parallel • Manylinux distributions adopt systemd as default • Red Hat Enterprise Linux, CentOS, Fedora, Arch Linux, openSUSE • Do not use daemon control script (/sbin/init, /etc/init.d/*, /etc/rc*.d) • /usr/lib/systemd • unit files: service, target, socket, device, mount, automount, path, snapshot, swap, timer • systemd utilities: systemctl, notify, analyze, cgis, cgtop, logictl, journalctl, nspawn

  33. Platform bootup • https://wiki.tizen.org/wiki/Porting_Guide entry point • .target vs .service • .target; servicegrouping • .service; process run

  34. Parsing unit file – example (1/8) • /usr/lib/systemd/system • cat sysinit.target target to parse

  35. Parsing unit file – example (2/8) • Website • http://www.freedesktop.org/wiki/software/systemd/ • systemd download • http://www.freedesktop.org/software/systemd/ manpage

  36. Parsing unit file – example (3/8) Can search all function and unit, configuration of systemd enter target index

  37. Parsing unit file – example (4/8) target unit file

  38. Parsing unit file – example (5/8) Description on unit file option

  39. Parsing unit file – example (6/8)

  40. Parsing unit file – example (7/8)

  41. Parsing unit file – example (8/8) • User awareness unit name= “System Initialization” • If emergency is running, wait • Run with local-fs.target, swap.target, sysinit.target.wants • Run after local-fs.target, swap.target, emergency.service, emergency.target • User can control service start and stop

  42. Different Sessions • [Unit], [Service], [Install], [Socket], [Swap], [Mount], … • example; telephony.service • [Unit]; general options • unit name = Telephony daemon • Run after modem.service • [Service]; processoptions • Run telephony-daemon as main process • [Install]; actual work of unit excute • Create telephony.service symlink at multi-user.target.wants

  43. References • systemd official Site http://www.freedesktop.org/wiki/Software/systemd/ • systemd FAQ (written by developer) • http://0pointer.de/blog/projects/the-biggest-myths

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