ECE 424 Embedded Systems Design Lecture 11 Embedded

ECE 424 Embedded Systems Design Lecture 11: Embedded Platform Boot Sequence Chapter 6 Ning Weng

Introduction • What is boot sequence? • Why we care? • 2 or 3 phases ─ BIOS/fireware: from processor reset vector ─ OS boot loader: from storage devices ─ OS Ning Weng ECE 424 2

Multi-core/threads Boot • Basic terms ─ Thread, core, package and SOC, • Bootstrap processor (BSP), Aps • Wait-for-SIPI state: wait for startup inter processor interrupt Ning Weng ECE 424 3

Image Storage Technologies Ning Weng ECE 424 4

S 1: Power Sequencing Ning Weng ECE 424 5

S 2: Reset • Reset vector: the location of these initial processor instructions ─ Inel 16 bytes • Hardware and software reset • Operation modes ─ Real ─ Flat protected mode ─ Segmented protected mode Ning Weng ECE 424 6

S 3: Early Initialization • CPU and memory controller initialization ─ ─ ─ ─ CPU IA Microcode update Device Initialization Memory Configuration Post-memory setup Shadowing AP Initialization Ning Weng ECE 424 7

S 4: Advanced Initialization • Platform related initialization, peripheral-specific ─ ─ ─ GPIO Interrupt/Cache controller Timers PCIe bus Image storage • … Ning Weng ECE 424 8

S 5: Boot Loader • Identifying the image and handoff to the image • See next slides for overall boot flow Ning Weng ECE 424 9

Ning Weng ECE 424 10

PXE (Networking Booting) Ning Weng ECE 424 11

Announcement • Read chapter 7 for OS overview • Friday, 9/21 Exam 1 • HW and Lab due Ning Weng ECE 424 12