Design of Embedded Systems Methodologies Tools and Applications

Design of Embedded Systems: Methodologies, Tools and Applications Alberto Sangiovanni-Vincentelli Dept. of EECS University of California Berkeley NSF UC Berkeley: Chess Vanderbilt University: ISIS University of Memphis: MSI Foundations of Hybrid and Embedded Software Systems

Disaggregation: Electronic Systems Design Chain Design Science System Design Platforms Implementation Fabrics IP Interfaces Manufacturing Chess/ISIS/MSI 2

Outline • Automotive Applications • Distributed System Design Methodology and Flow • Platform-based Design • UAV Control Example • Metropolis Chess/ISIS/MSI 3

The Automotive Electronic Design Chain Product Definition Platforms Design And Assembly IP Interfaces Chess/ISIS/MSI 4

Automotive Supply Chain: Car Manufacturers Product Specification & Architecture Definition (e. g. , determination of Protocols and Communication standards) System Partitioning and Subsystem Specification Critical Software Development System Integration Chess/ISIS/MSI 5

Fault Tolerant Mobile Communications MOST Firewire Fail Safe CAN Lin Navigation Access to WWW DAB Fire Wall Today, more than 80 Microprocessors and millions of lines of code Theft warning Air Conditioning Door Module Gate Way Light Module ABS CAN TTCAN Gate Way Fault Functional Body Electronics Body Functions Body Electronics Driving and Vehicle Dynamic Functions Information Systems Telematics Electronics for the Car: A Distributed System Steer by Wire Shift by Wire Engine Management Brake by Wire Flex. Ray Chess/ISIS/MSI 6

Automotive Supply Chain: Tier 1 Subsystem Providers 1 2 3 4 5 6/7 8 9 10 11 Transmission ECU Actuation group Engine ECU DBW Active shift display Up/Down buttons City mode button Up/Down lever Accelerator pedal position sensor Brake switch §Subsystem Partitioning §Subsystem Integration §Software Design: Control Algorithms, Data Processing §Physical Implementation and Production Chess/ISIS/MSI 7

Automotive Supply Chain: Tier 2 Platform & IP Providers Application Platform layer (@ 10% of total SW) SW Platform layer (> 60% of total SW) -------Water temp. Odometer Tachometer Speedometer Application Libraries OSEK RTOS Customer Libraries Application Specific Software Application Programming Interface Sys. Config. (> Boot Loader I/O drivers & handlers 20 configurable modules) CCP KWP 2000 Transport OSEK COM m. Controllers Library HW layer Nec 78 k HC 08 HC 12 H 8 S 26 MB 90 ST 10 §“Software” platform: RTOS and communication layer §“Hardware” platform: Hardware and IO drivers Chess/ISIS/MSI 8

Complexity, Quality, Time-to-Market: TODAY CLUSTER TELEMATIC UNIT 128 KB 184 KB 8 MB 50. 000 30. 000 45. 000 300. 000 6 LINES/DAY 10 LINES/DAY* 3000 PPM 2500 PPM 2000 PPM 1000 PPM CHANGING RATE 3 YEARS 2 YEARS 1 YEAR < 1 YEAR DEV. EFFORT 40 MAN-YEAR 12 MAN-YEAR 30 MAN-YEAR 200 MAN-YEAR VALIDATION TIME 5 MONTHS 1 MONTH 2 MONTHS TIME TO MARKET 24 MONTHS 18 MONTHS 12 MONTHS < 12 MONTHS PWT UNIT BODY GATEWAY MEMORY 256 KB LINES OF CODE PRODUCTIVITY RESIDUAL DEFECT RATE @ END OF DEV * C++ CODE INSTRUMENT FABIO ROMEO, Magneti-Marelli Design Automation Conference, Las Vegas, June 20 th, 2001 Chess/ISIS/MSI 9

Embedded Software Design: Our Take • Embedded Software Design must not be seen as a problem in isolation, it is an, albeit essential, aspect of EMBEDDED SYSTEM DESIGN • Our vision is to change the way in which ESW is developed today by linking it: – Upwards in the abstraction layers to system functionality – Downwards in the programmable platforms that support it thus providing the means to verify whether the constraints posed on Embedded Systems are met. Chess/ISIS/MSI 10

Outline • Automotive Applications • Distributed System Design Methodology and Flow • Platform-based Design • UAV Control Example • Metropolis Chess/ISIS/MSI 11

Virtual Integration is key for Distributed System Design Functional Network Definition analysis Fctn and Fct 1 Validation (Timed and un-Timed) Fctn Fct 1 ECU SW Scheduling Adoption Spec and Validation & & specification & Sim. Virtual Communication Protocol system design Adoption and Validation Integration virtual Spec & Sim. ECU 1 Integration implementation real Safety Concept Proof via Fault Injection ECU Optimization/Derivative Integration ECU 1 calibration Design ECUk production & after sales now tomorrow Source BMW Chess/ISIS/MSI 12

Design Flow Requirement Specification Algorithm Specifications Algorithm Analysis Environment. Test Bench Modeling Algorithm Design Algorithms Virtual Prototyping Architectural Modeling Behavioral Modeling Architectu re IP Authoring Architectural IPs Behavior IPs Mapping Distributed Architecture Analysis ECU Scheduling Analysis Algorithm Performance Synthesis Export System Model SW platform Performance Simulation SW tasks Compile/Li nk/Load Physical Prototyping Communication Protocol Configuration Load Chess/ISIS/MSI 13

Focus on Safety-Critical Real Time • Most challenging problem • Needs tight integration between algorithms and implementation • Constraints include timing and fault tolerance • Fault tolerance can be addressed at all levels of abstraction Chess/ISIS/MSI 14

Safety Critical Issues: Fault Analysis CPU+ Sensors Actuators RAM Safety Concept Proof via Fault Injection (HW, SW, Bus. . ) Bus Interface Tasks HW Int. OS Host (u. C) Task 1 Communication Controller (CC) Task 2 Dev. Driv. Bus Guardian (BG) f f f Network I/O CPU f Bus Driver (BD) f Chess/ISIS/MSI 15

DRAFTS: Distributed Real-time Applications Fault Tolerant Scheduling • Automatic (off-line) synthesis of fault tolerant schedules for periodic algorithms on a distributed architecture • Automatic (off-line) verification that all intended faults are covered Long-term goals: • Design Methodology for Safety Critical Distributed Systems • Manage the design complexity of modern Drive-By. Wire applications C. Pinello, UCB, T. Demmeler and J. Ehret, BMW Chess/ISIS/MSI 16

DRAFTS Strategy • Identify critical functionality and possible faults • Replicate critical functionality to withstand faults • Exploit architecture redundancy to speedup execution (in absence of faults) • Functional Verification that all intended faults are covered Chess/ISIS/MSI 17

Outline • Automotive Applications • Distributed System Design Methodology and Flow • Platform-based Design • UAV Control Example • Metropolis Chess/ISIS/MSI 18

ASV Triangles Application Space Application Instance Platform Mapping System Platform (HW and SW) Platform Design-Space Export Platform Instance Architectural Space Chess/ISIS/MSI 19

Platforms: Evolution In general, a platform is an abstraction layer that covers a number of possible refinements into a lower level. The platform representation is a library of components including interconnects from which the lower level refinement can choose. Platform stack { Platform Mapping Tools Platform Chess/ISIS/MSI 20

Principles of Platform methodology: Meet-in-the-Middle • Top-Down: – Define a set of abstraction layers – From specifications at a given level, select a solution (controls, components) in terms of components (Platforms) of the following layer and propagate constraints • Bottom-Up: – Platform components (e. g. , micro-controller, RTOS, communication primitives) at a given level are abstracted to a higher level by their functionality and a set of parameters that help guiding the solution selection process. The selection process is equivalent to a covering problem if a common semantic domain is used. Chess/ISIS/MSI 21

Outline • Automotive Applications • Distributed System Design Methodology and Flow • Platform-based Design • UAV Control Example • Metropolis Chess/ISIS/MSI 22

Platform-Based Design of Unmanned Aerial Vehicles (source: J. Liebman) I Platform. Based Design II III UAV System Synchronous Embedded Control Synchronous Platform Based UAV Design Chess/ISIS/MSI 23

UAV System: Sensor Overview • Goal: basic autonomous flight R-50 Hovering • Need: UAV with allowable payload • Need: combination of GPS and Inertial Navigation System (INS) • GPS (senses using triangulation) • Outputs accurate position data • Available at low rate & has GPS Card jamming • INS (senses using accelerometer and rotation sensor) • Outputs estimated position with GPS Antenna unbounded drift over time • Available at high rate • Fusion of GPS & INS provides needed high rate and accuracy INS Chess/ISIS/MSI 24

UAV System: Sensor Configurations • Sensors may differ in: • Data formats, initialization schemes (usually requiring some bit level coding), rates, accuracies, data communication schemes, and even data types • Differing Communication schemes requires the most custom written code per sensor Software Request Software Shared memory d INS d GPS Pull Configuration INS GPS Push Configuration Chess/ISIS/MSI 25

Platform Based Design for UAVs • Goal – Abstract details of sensors, actuators, and vehicle hardware from control applications • How? - Synchronous Embedded Programming Language (i. e. Giotto) Platform Control Applications (Matlab) Synchronous Embedded Programming (Giotto) Application Space Architectural Space Sensors: INS, GPS Actuators: Servo Interface Vehicles: Yamaha R-50/RMax Chess/ISIS/MSI 26

Platform Based Design for UAVs • • Device Platform – Isolates details of sensor/actuators from embedded control programs – Communicates with each sensor/actuator according to its own data format, context, and timing requirements – Presents an API to embedded control programs for accessing sensors/actuators Language Platform – Provides an environment in which synchronous control programs can be scheduled and run – Assumes the use of generic data formats for sensors/actuators made possible by the Device Platform Control Applications (Matlab) Synchronous Embedded Programming (Giotto) Application Space Architectural Space Language Platform Device Platform Virtual Avionics Sensors: INS, GPS Platform Actuators: Servo Interface Vehicles: Yamaha R-50/RMax Chess/ISIS/MSI 27

Outline • Automotive Applications • Distributed System Design Methodology and Flow • Platform-based Design • UAV Control Example • Metropolis Chess/ISIS/MSI 28

Metropolis Framework Application-specific methodologies Multi-media, wireless communication, mechanical controls, processors Meta-model Library • Models of computation Meta-model Library Infrastructure • Metropolis meta-model - language - modeling mechanisms • Meta-model compiler • Architecture platforms Tools Simulator QSS PIG STARS SPIN … Chess/ISIS/MSI 29

Metropolis Project: main participants etropolis • UC Berkeley (USA): methodologies, modeling, formal methods • Cadence Berkeley Labs (USA): methodologies, modeling, formal methods • Politecnico di Torino (Italy): modeling, formal methods • Universitat Politecnica de Catalunya (Spain): modeling, formal methods • Philips Research (Netherlands): methodologies (multi-media) • Nokia (USA, Finland): methodologies (wireless communication) • BWRC (USA): methodologies (wireless communication) • BMW (USA): methodologies (fault-tolerant automotive controls) • Intel (USA): methodologies (microprocessors) • STMicroelectronics (France, Italy): methodologies (wireless platforms) • Cypress (USA): methodologies (network processors, p. SOC, all projects) Chess/ISIS/MSI 30

Metropolis meta-model Concurrent specification with a formal execution semantics: • Computation : f : X Z - process : generates a sequence of events Key difference with respect to • Communication evaluation and manipulation UML, : state System. C, …!!! - medium : defines states and methods • Coordination : constraints over concurrent actions - quantity : annotation of each event (time, energy, memory, …) - logic : relates events and quantities, defines axioms on quantities - quantity-manager : algorithm to realize annotation subject to relational constraints Chess/ISIS/MSI 31

Metropolis Meta-Model • Must describe objects at different levels of abstraction – Do not commit to the semantics of any particular model of computation • Define a set of “building blocks” – specifications with many useful Mo. Cs can be described using the building blocks – Processes, communication media and schedulers separate computation, communication and coordination Computation P 1 p. X Communication p. Z M M’ P 2 p. X p. Z M’ S P 1. p. Z. write( ) P 2. p. X. read( ) Coordination Chess/ISIS/MSI 32

Supporting Theory • Provide a semantic foundations for integrating different models of computation – Independent of the design language – Not just specific to the Metropolis meta-model • Maximize flexibility for using different levels of abstraction – For different parts of the design – At different stages of the design process – For different kinds of analysis • Support many forms of abstraction – Model of computation (model of time, synchronization, etc. ) – Scoping – Structure (hierarchy) Chess/ISIS/MSI 33

Concluding Remarks • Applications are critical to drive research and to test quality of results • Safety-critical Real Time emphasis • Rigorous methodology for distributed systems • General framework to express designs at all levels of hierarchy and to support integration of foreign tools and designs Chess/ISIS/MSI 34

Embedded Software: Today Chess/ISIS/MSI 35

Embedded Software: Future? Chess/ISIS/MSI 36