"Real-Time Concepts for Embedded Systems" - читать интересную книгу автора (Li Qing, Yao Carolyn)
Qing Li and Carolyn Yao Real-Time Concepts for Embedded Systems Preface Audience for this Book Acknowledgments Chapter 1: Introduction Overview 1.1 Real Life Examples of Embedded Systems 1.1.1 Embedded Systems in the Home Environment 1.1.2 Embedded Systems in the Work Environment 1.1.3 Embedded Systems in Leisure Activities 1.1.4 Defining the Embedded System 1.1.5 Embedded Processor and Application Awareness 1.1.6 Hardware and Software Co-Design Model 1.1.7 Cross-Platform Development 1.1.8 Software Storage and Upgradeability 1.2 Real-Time Embedded Systems 1.2.1 Real-Time Systems 1.2.2 Characteristics of Real-Time Systems 1.2.3 Hard and Soft Real-Time Systems 1.3 The Future of Embedded Systems 1.4 Points to Remember Chapter 2: Basics Of Developing For Embedded Systems 2.1 Introduction 2.2 Overview of Linkers and the Linking Process 2.3 Executable and Linking Format 2.4 Mapping Executable Images into Target Embedded Systems 2.4.1 Linker Command File 2.4.2 Mapping Executable Images 2.4.3 Example in Practice 2.5 Points to Remember Chapter 3: Embedded System Initialization 3.1 Introduction 3.2 Target System Tools and Image Transfer 3.2.1 Embedded Loader 3.2.2 Embedded Monitor 3.2.3 Target Debug Agent 3.3 Target Boot Scenarios 3.3.1 Executing from ROM Using RAM for Data 3.3.2 Executing from RAM after Image Transfer from ROM 3.3.3 Executing from RAM after Image Transfer from Host 3.4 Target System Software Initialization Sequence 3.4.1 Hardware Initialization 3.4.2 RTOS Initialization 3.4.3 Application Software Initialization 3.5 On-Chip Debugging 3.6 Points to Remember Chapter 4: Introduction To Real-Time Operating Systems 4.1 Introduction 4.2 A Brief History of Operating Systems 4.3 Defining an RTOS 4.4 The Scheduler 4.4.1 Schedulable Entities 4.4.2 Multitasking 4.4.3 The Context Switch 4.4.4 The Dispatcher 4.4.5 Scheduling Algorithms 4.5 Objects 4.6 Services 4.7 Key Characteristics of an RTOS 4.7.1 Reliability 4.7.2 Predictability 4.7.3 Performance 4.7.4 Compactness 4.7.5 Scalability 4.8 Points to Remember Chapter 5: Tasks 5.1 Introduction 5.2 Defining a Task 5.3 Task States and Scheduling 5.3.1 Ready State 5.3.2 Running State 5.3.3 Blocked State 5.4 Typical Task Operations 5.4.1 Task Creation and Deletion 5.4.2 Task Scheduling 5.4.3 Obtaining Task Information 5.5 Typical Task Structure 5.5.1 Run-to-Completion Tasks 5.5.2 Endless-Loop Tasks 5.6 Synchronization, Communication, and Concurrency 5.7 Points to Remember Chapter 6: Semaphores 6.1 Introduction 6.2 Defining Semaphores 6.2.1 Binary Semaphores 6.2.2 Counting Semaphores 6.2.3 Mutual Exclusion (Mutex) Semaphores 6.3 Typical Semaphore Operations 6.3.1 Creating and Deleting Semaphores 6.3.2 Acquiring and Releasing Semaphores 6.3.3 Clearing Semaphore Task-Waiting Lists 6.3.4 Getting Semaphore Information 6.4 Typical Semaphore Use 6.4.1 Wait-and-Signal Synchronization 6.4.2 Multiple-Task Wait-and-Signal Synchronization 6.4.3 Credit-Tracking Synchronization 6.4.4 Single Shared-Resource-Access Synchronization 6.4.5 Recursive Shared-Resource-Access Synchronization 6.4.6 Multiple Shared-Resource-Access Synchronization 6.5 Points to Remember Chapter 7: Message Queues 7.1 Introduction 7.2 Defining Message Queues 7.3 Message Queue States 7.4 Message Queue Content 7.5 Message Queue Storage 7.5.1 System Pools 7.5.2 Private Buffers 7.6 Typical Message Queue Operations 7.6.1 Creating and Deleting Message Queues 7.6.2 Sending and Receiving Messages 7.6.3 Obtaining Message Queue Information 7.7 Typical Message Queue Use 7.7.1 Non-Interlocked, One-Way Data Communication 7.7.2 Interlocked, One-Way Data Communication 7.7.3 Interlocked, Two-Way Data Communication 7.7.4 Broadcast Communication 7.8 Points to Remember Chapter 8: Other Kernel Objects 8.1 Introduction 8.2 Pipes 8.2.1 Pipe Control Blocks 8.2.2 Pipe States 8.2.3 Named and Unnamed Pipes 8.2.4 Typical Pipe Operations 8.2.5 Typical Uses of Pipes 8.3 Event Registers 8.3.1 Event Register Control Blocks 8.3.2 Typical Event Register Operations 8.3.3 Typical Uses of Event Registers 8.4 Signals 8.4.1 Signal Control Blocks 8.4.2 Typical Signal Operations 8.4.3 Typical Uses of Signals 8.5 Condition Variables 8.5.1 Condition Variable Control Blocks 8.5.2 Typical Condition Variable Operations 8.5.3 Typical Uses of Condition Variables 8.6 Points to Remember Chapter 9: Other RTOS Services 9.1 Introduction 9.2 Other Building Blocks 9.2.1 TCP/IP Protocol Stack 9.2.2 File System Component 9.2.3 Remote Procedure Call Component 9.2.4 Command Shell 9.2.5 Target Debug Agent 9.2.6 Other Components 9.3 Component Configuration 9.4 Points to Remember Chapter 10: Exceptions and Interrupts 10.1 Introduction 10.2 What are Exceptions and Interrupts? 10.3 Applications of Exceptions and Interrupts 10.3.1 Internal Errors and Special Conditions Management 10.3.2 Hardware Concurrency and Service Request Management 10.4 A Closer Look at Exceptions and Interrupts 10.4.1 Programmable Interrupt Controllers and External Interrupts 10.4.2 Classification of General Exceptions 10.4.3 General Exception Priorities 10.5 Processing General Exceptions 10.5.1 Installing Exception Handlers 10.5.2 Saving Processor States 10.5.3 Loading and Invoking Exception Handlers 10.5.4 Nested Exceptions and Stack Overflow 10.5.5 Exception Handlers 10.6 The Nature of Spurious Interrupts 10.7 Points to Remember Chapter 11: Timer and Timer Services 11.1 Introduction 11.2 Real-Time Clocks and System Clocks 11.3 Programmable Interval Timers 11.4 Timer Interrupt Service Routines 11.5 A Model for Implementing the Soft-Timer Handling Facility 11.5.1 Possible Processing Delays 11.5.2 Implementation Considerations 11.6 Timing Wheels 11.6.1 Issues 11.6.2 Hierarchical Timing Wheels 11.7 Soft Timers and Timer Related Operations 11.8 Points to Remember Chapter 12: I/O Subsystem 12.1 Introduction 12.2 Basic I/O Concepts 12.2.1 Port-Mapped vs. Memory-Mapped I/O and DMA 12.2.2 Character-Mode vs. Block-Mode Devices 12.3 The I/O Subsystem 12.3.1 Standard I/O Functions 12.3.2 Mapping Generic Functions to Driver Functions 12.3.3 Associating Devices with Device Drivers 12.4 Points to Remember Chapter 13: Memory Management 13.1 Introduction 13.2 Dynamic Memory Allocation in Embedded Systems 13.2.1 Memory Fragmentation and Compaction 13.2.2 An Example of malloc and free 13.2.3 Finding Free Blocks Quickly 13.2.4 The free Operation 13.3 Fixed-Size Memory Management in Embedded Systems 13.4 Blocking vs. Non-Blocking Memory Functions 13.5 Hardware Memory Management Units 13.6 Points to Remember Chapter 14: Modularizing An Application For Concurrency 14.1 Introduction 14.2 An Outside-In Approach to Decomposing Applications 14.3 Guidelines and Recommendations for Identifying Concurrency 14.3.1 Units of Concurrency 14.3.2 Pseudo versus True Concurrent Execution 14.3.3 Some Guidelines 14.4 Schedulability Analysis-Rate Monotonic Analysis 14.4.1 Basic RMA Schedulability Test 14.4.2 Extended RAM Schedulability Test 14.5 Points to Remember Chapter 15: Synchronization And Communication 15.1 Introduction 15.2 Synchronization 15.2.1 Resource Synchronization 15.2.2 Activity Synchronization 15.2.3 Implementing Barriers 15.3 Communication 15.4 Resource Synchronization Methods 15.4.1 Interrupt Locks 15.4.2 Preemption Locks 15.5 Critical Section Revisited 15.6 Common Practical Design Patterns 15.6.1 Synchronous Activity Synchronization 15.6.2 Asynchronous Event Notification Using Signals 15.6.3 Resource Synchronization 15.7 Specific Solution Design Patterns 15.7.1 Data Transfer with Flow Control 15.7.2 Asynchronous Data Reception from Multiple Data Communication Channels 15.7.3 Multiple Input Communication Channels 15.7.4 Using Condition Variables to Synchronize between Readers and Writers 15.7.5 Sending High Priority Data between Tasks 15.7.6 Implementing Reader-Writer Locks Using Condition Variables 15.8 Points to Remember Chapter 16: Common Design Problems 16.1 Introduction 16.2 Resource Classification 16.3 Deadlocks 16.3.1 Resource Request Models 16.3.2 Deadlock Detection 16.3.3 Deadlock Recovery 16.3.4 Deadlock Avoidance 16.3.5 Deadlock Prevention 16.4 Priority Inversion 16.4.1 Priority Inheritance Protocol 16.4.2 Ceiling Priority Protocol 16.4.3 Priority Ceiling Protocol 16.5 Points to Remember Appendix A: References
Qing Li and Carolyn Yao Real-Time Concepts for Embedded Systems We live in a world today in which software plays a critical part. The most critical soft ware is not running on large systems and PCs. Rather, it runs inside the infrastructure and in the devices that we use every day. Our transportation, communications, and energy systems won't work if the embedded software contained in our cars, phones, routers and power plants crashes. The design of this invisible, embedded software is crucial to all of us. Yet, there has been a real shortage of good information as to effective design and implementation practices specific to this very different world. Make no mistake, it is indeed different and often more difficult to design embedded software than more traditional programs. Time, and the interaction of multiple tasks in real-time, must be managed. Seemingly esoteric concepts, such as priority inversion, can become concrete in a hurry when they bring a device to its knees. Efficiency-a small memory footprint and the ability to run on lower cost hardware-become key design considerations because they directly affect cost, power usage, size, and battery life. Of course, reliability is paramount when so much is at stake-company and product reputations, critical infrastructure functions, and, some times, even lives. Mr. Li has done a marvelous job of pulling together the relevant information. He lays out the issues, the decision and design process, and the available tools and methods. The latter part of the book provides valuable insights and practical experiences in understanding application development, common design problems, and solutions. The book will be helpful to anyone embarking on an embedded design project, but will be of par ticular help to engineers who are experienced in software development but not yet in real-time and embedded software development. It is also a wonderful text or reference volume for academic use. The quality of the pervasive, invisible software surrounding us will determine much about the world being created today. This book will have a positive effect on that quality and is a welcome addition to the engineering bookshelf. Chairman and Co-Founder, Wind River
