A Critical Analysis of the Windows mLAN Driver

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A Critical Analysis of the Windows mLAN Driver

• Supervisor Prof. Foss
• By Shaun Miles

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Overview

• What is mLAN?
• Project Focus
• Windows Driver Model more in depth
• mLAN Driver Analysis
• Timeline
• Questions?

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What is mLAN?

• Yamaha using FireWire to connect studio devices
  via 1394 nodes implementing the mLAN architecture
• Allows easy connection of equipment in a
  professional environment
• Moving away from legacy studios
• Peer-to-peer transfer of data no need for host
  server
• Serial bus high speed
• Isochronous and Asynchronous transfer methods
• Standardised built on CSR architecture or 1394

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What is mLAN cont

• Can have PC host controller
• modelling device connection
• connects input/output plugs between devices
• allows easy routing of audio

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Project Focus

• Windows drivers must conform to WDM architecture
• provides defined communication stream
• how applications access hardware/devices
• call appropriate system services
• mLAN Driver virtual management of devices on the
  firewire bus via interface card in PC
• Understand yamahas mLAN driver approach
• Driver design object model and sequence diagrams
• Write IOCTLs wrapper classes

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Windows Driver Model - WDM

• Architecture for Windows Operating system
• designing
• developing
• Kernel-mode driver
• system calls
• has to be reliable
• Layered approach
• driver stacks
• moves away from monolithic drivers

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Windows Kernel

• Power Management
• handles device power management messages
• I/O Manager
• builds suitable IRPs from requests from
  applications
• passes IRPs to driver stack
• PnP Manager
• manages device objects that represent physical
  devices
• handles allocates hardware resource requests

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I/O Request Packets IRPs

• Built by I/O Manager
• In response to application
• system communicates with kernel-mode drivers
• Driver Communication packets
• requests an action from device
• handled by relevent driver in stack
• passed on until request is satisfied

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IOCTLs

• I/O Control Codes part of IRP
• Specifies function or action other than
  read/write requests
• Defined by unique code
• Project focus IOCTLs wrapper classes
• Interface an application can communicate directly
  with a device via its driver

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Device and Driver Objects

• Driver object
• used by I/O Manager to access driver code
• contains pointers to driver entry routines
• created in I/O Manager on driver install and load
• Device object
• represents a logical, virtual, or physical device
  
• handles I/O requests (IRPs)
• does most of the processing

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Example of driver stack

• Simplified view
• I/O manager creates IRP
• Drivers pass down until request satisfied

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mLAN Driver Analysis

• CmLANBusDriver
• Driver object
• handles driver initialisation, device management
• CmLanBus
• Device object
• implements PnP, Power and IRP management
  functionality
• Makes use of other client drivers

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Time Line

• Third Term
• Produce Object Model
• Extrapolate Sequence Diagrams
• Write IOCTLS wrapper classes for driver
• Project Poster
• Fourth Term
• Finish and test IOCTLS wrappers
• Write short paper
• Write thesis

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Questions?

• Thank you