26.4.3 I2C Using Gpio Versus Dedicated I2C Hardware | Intel IXP400

Intel® IXP400 Software

I2C Driver (IxI2cDrv)

Figure 113. Sequence Flow Diagram for Slave Transmit in Polling Mode

client		i2cDrv

ixI2cDrvSlaveAddrAndGenCallDetectedCheck

IX_I2C_SLAVE_ADDR_NOT_DETECTED

ixI2cDrvSlaveAddrAndGenCallDetectedCheck

IX_I2C_SLAVE_WRITE_DETECTED

store data into first buf ixI2cDrvSlaveDataTransmit (first buf)

IX_I2C_SLAVE_WRITE_BUFFER_EMPTY

store data into second buf ixI2cDrvSlaveOrGenDataReceive (second buf)

IX_I2C_SUCCESS

Check Slave Addr Detected

Check Slave Addr Detected

transmit data

transmit data

B4378-01

26.4.3I2C Using GPIO Versus Dedicated I2C Hardware

Some supported operating systems include support for emulating the I2C bus using GPIO lines on the processor.

The I2C driver using a dedicated I2C hardware is a totally different implementation from the driver using GPIO lines. Most of the APIs in a driver using a GPIO implementation are very low level (dedicated to controlling the SDA and SCL lines) and combine to make one transaction. The driver APIs using dedicated I2C hardware (such as with IxI2cDrv) will be limited to the control provided by the hardware unit on the processor. Furthermore, the dedicated I2C hardware implementation allows more advanced features supported by the hardware, such as those to support multi-master on the bus, therefore allowing the IXP46X network processors to act as slave devices.

Programmer’s Guide	IXP400 Software Version 2.0	April 2005
	Document Number: 252539, Revision: 007	339

Image 339

Intel IXP400 26.4.3 I2C Using Gpio Versus Dedicated I2C Hardware, Sequence Flow Diagram for Slave Transmit in Polling Mode

Contents

Programmer’s Guide Intel IXP400 Software IXP400 Software Version Intel IXP400 Software Contents 1.1 100 118 152 Contents Access-Layer Components 225 17.9 Operating System Adsl Driver Figures 102 Tables AQM 300 Date Revision Description Revision History Intended Audience Introduction1Versions Supported by this Document Hardware Supported by this Release How to Use this Document About the ProcessorsChapters Description Document Title Document # Related Documents Acronyms Document Title Document #Acronym Description CPU HSS MSB SIP High-Level Overview Software Architecture Overview Software Architecture Overview Deliverable Model Access Library Source Code Documentation Operating System SupportDevelopment Tools Ixposal Include Src Ixp400xscalesw Release Directory Structure \---include +---npeMh Threading and Locking Policy Polled and Interrupt OperationStatistics and MIBs Global Dependencies Global Dependency Chart This page is intentionally left blank Buffer Management What’s NewOverview Intel IXP400 Software Buffer Flow Buffer Management Raw Buffers Ixpbuf User Interface Ixpbuf Structure and Macros Ixpbuf Structure Osal Ixpbuf structure and macros API User Interface to Ixpbuf Ixmbuf OS-Dependent Buffer Format Pool Management Fields Ixne IXP400 NPE Shared Structure Ixpbuf ixctrl Structure Ixpbuf NPE Shared Structure Mapping of Ixmbuf to Shared Structure Ixreserved Ixmbuf StructureInternal Ixmbuf Field Format Sheet 1 Ixnext Ixosalmbufnextbufferinpktptr Field / Macro Purpose Used by Access-Layer? Internal Ixmbuf Field Format Sheet 2Ixmbuf Field Details Sheet 1 Mapping to OS Native Buffer Types VxWorks* Mblk BufferIxmbuf Field Details Sheet 2 Ixmbuf to Mblk Mapping Linux* skbuff Buffer Buffer Translation Functions Following fields will get updated in the skbuffer Tx Path Caching Strategy Rx Path Caching Strategy SummaryBuffer Management Tx Cache Flushing Example Intel IXP400 Software This page is intentionally left blank IxAtmdAcc Component Features Access-Layer Components ATM Driver Access IxAtmdAcc API Access-Layer Components ATM Driver Access IxAtmdAcc API Configuration Services Utopia Port-Configuration ServiceATM Traffic-Shaping Services VC-Configuration Services Transmission Services Buffer Transmission for a Scheduled Port Scheduled Transmission Schedule Table Description Transmit-Done Processing Transmission Triggers Tx-Low Notification Transmit Done Based on a Threshold Level Tx Done Recycling Using a Threshold Level Transmit Disconnect Tx Done Recycling Using a Polling Mechanism Tx Disconnect Receive Services Receive Triggers Rx-Free-Low Notification Receive ProcessingReceive Based on a Threshold Level Rx Using a Threshold Level Receive Disconnect RX Using a Polling Mechanism Buffer Contents Buffer ManagementBuffer Allocation Field Description Ixpbuf Fields Required for TransmissionIxpbuf Fields of Available Buffers for Reception Ixpbuf Fields Modified During Reception Sheet 1 Buffer-Chaining Constraints Error HandlingAPI-Usage Errors Buffer-Size Constraints Real-Time Errors Real-Time ErrorsCause Consequences and Side Effects Corrective Action Access-Layer Components ATM Manager IxAtmm API IxAtmm Component FeaturesIxAtmm Overview Utopia Level-2 Port Initialization Access-Layer Components ATM Manager IxAtmm API ATM-Port Management Service Model Services Provided by Ixatmm Tx/Rx Control Configuration Configuration of Traffic Control Mechanism Memory Requirements Error HandlingDependencies Management Interfaces Performance IxAtmSch Component Features Access-Layer Components ATM Transmit Scheduler IxAtmSch Access-Layer Components ATM Transmit Scheduler IxAtmSch API Supported Traffic TypesTraffic Type Supported Num VCs Connection Admission Control CAC Function Schedule Table Scheduling and Traffic Shaping Schedule Service Model Minimum Cells Value minCellsToScheduleMaximum Cells Value maxCells Timing and Idle Cells Per VC Data Per Port Data Total Code SizeData Memory IxAtmSch Data Memory Usage Latency Access-Layer Components Security IxCryptoAcc API Access-Layer Components Security IxCryptoAcc API IxCryptoAcc API ArchitectureIxCryptoAcc Interfaces Basic API Flow Basic IxCryptoAcc API Flow Context Registration and the Cryptographic Context Database Intel IXP400 Software IxCryptoAcc API Call Process Flow for CCD Updates Structure Size in Bytes Total Size in Bytes Buffer and Queue ManagementMemory Requirements IxCryptoAcc Data Memory Usage Sheet 1 IxCryptoAcc Data Memory Usage Sheet 2 Dependencies IxCryptoAccHashKeyGenerate Other API Functionality IPSec Background and Implementation IPSec ServicesEndianness Import and Export of Cryptographic Technology IxCryptoAcc, NPE and IPSec Stack Scope Relationship Between IPSec Protocol and Algorithms IPSec Packet Formats Reference ESP Dataflow Authentication Header ESP Data Flow Reference AH Dataflow IPSec API Call Flow Hardware Acceleration for IPSec Services IPSec API Call Flow Hmac with Key Size Greater Than 64 Bytes Special API Use Cases CCM Operation Flow AES CBC Encryption For MIC WEP Services IPSec Assumptions, Dependencies, and LimitationsWEP Background and Implementation WEP Frame with Request Parameters Hardware Acceleration for WEP Services NPE Microcode Images WEP API Call FlowIxCryptoAccNpeWepPerform IxCryptoAccXscaleWepPerform WEP Perform API Call Flow Encryption/Decryption AuthenticationCombined Mode Operations SSL and TLS Protocol Usage Models Cipher Key Sizes Parity Bit Actual Key Size Supported Encryption and Authentication AlgorithmsEncryption Algorithms Supported Encryption Algorithms Cipher Block Chaining CBC Counter Mode CTRCipher Modes Electronic Code Book ECB Authentication Algorithms Supported Authentication AlgorithmsAuthentication Algorithm Data Block Size Bits Key Size Bits 114 Document Number 252539, Revision Access-Layer Components DMA Access Driver IxDmaAcc API FeaturesAssumptions Access-Layer Components DMA Access Driver IxDmaAcc API DMA Access-Layer API IxDmaAcc Component Overview IxDmaAccDescriptorManager Parameters Description Transfer Width Transfer ModeSource Address Destination Address Transfer Length Addressing Modes Transfer Mode Supported ModesIncrement 122 Document Number 252539, Revision Control Flow Data Flow IxDmaAcc Control Flow DMA Initialization IxDMAcc Initialization DMA Configuration and Data Transfer DMA Transfer Operation Restrictions of the DMA Transfer Little Endian IxEthAcc Overview Access-Layer Components Ethernet Access IxEthAcc API Ethernet Access Layers Architectural Overview Access-Layer Components Ethernet Access IxEthAcc APIRole of the Ethernet NPE Microcode 4 MAC/PHY Configuration Queue ManagerLearning/Filtering Database Ethernet Access Layers Component Features Data Plane Ethernet Access Layers Block Diagram Port Initialization Ethernet Frame TransmissionTransmission Flow Transmit Buffer Management and Priority TxEnetDone Ethernet Transmit Frame Data Buffer Flow Using Chained IXOSALMBUFs for Transmission / Buffer Sizing Ethernet Frame ReceptionTx Fifo Priority Ethernet Receive Frame API Overview Receive Flow Receive Buffer Management and Priority Buffer SizingSupplying Buffers Codelet or client application Programmer’s Guide Rx Fifo Priority QoS Mode Freeing BuffersRecycling Buffers No Receive Polling Additional Receive Path Information Control Path Data-Plane EndiannessMaximum Ethernet Frame Size IxEthAcc and Secondary Components Frame Check Sequence MAC Duplex SettingsEthernet MAC Control MII I/O 1.6 802.3x Flow Control Promiscuous ModeNon-Promiscuous Mode MAC Filtering Emergency Security Port Shutdown InitializationShared Data Structures NPE Loopback Ixpneflags Field Format Ixosalmbuf Structure Format Queue Field Description Eth 150 Document Number 252539, Revision Ixosalmbuf Port ID Field Format Field Bit Values Management InformationIxosalmbuf Port ID Field Values Ixpneflags.linkprot Field Values Object Increment Criteria Managed Objects for Ethernet Receive Managed Objects for Ethernet Transmit IxEthDB Functional Behavior Access-Layer Components Ethernet Database IxEthDB API Access-Layer Components Ethernet Database IxEthDB API MAC Address Learning and FilteringLearning and Filtering Node Learning/Filtering General Characteristics Other MAC Learning/Filtering Usage ModelsPort Definitions Port Dependency Map Provisioning Static and Dynamic EntriesAging Database Maintenance Frame Size FilteringRecord Management Source MAC Address Firewall Filtering Example Based Upon Maximum Frame SizeMAC Address Block/Admission Invalid MAC Address Filtering 10.3.4 802.1Q Vlan Background Vlan Data in Ethernet Frames Untagged MAC Frame FormatVlan Tagged MAC Frame Format Database Records Associated With Vlan IDs Acceptable Frame Type FilteringVlan Tag Format Port-Based Vlan Membership Filtering Ingress Tagging and Tag Removal Port and VLAN-Based Egress Tagging and Tag Removal Special Conditions Egress Vlan Tagging/Untagging Behavior Matrix Tag Mode Frame Status Action 10.3.5 802.1Q User Priority / QoS Support Port ID ExtractionPriority Aware Transmission QoS on Receive for 802.1Q Tagged Frames Receive Priority Queuing QoS on Receive for Untagged Frames Priority to Traffic Class Mapping IEEE802.11 Frame Format Default Priority to Traffic Class Mapping10.3.6 802.3 / 802.11 Frame Conversion Background 802.3 and 802.11 Frame Formats AP-STA and AP-AP Modes IEEE802.11 Frame Control FC Field Format Receive Path How the 802.3 / 802.11 Frame Conversion Feature Works Field AP to STA mode AP to AP mode To 802.11 Header Conversion RulesTransmit Path Frame Type 10.3.6.3 802.3 / 802.11 API Details11 to 802.3 Header Conversion Rules Input 802.11 Frame Values Output 802.3 Frame Field Values Spanning Tree Protocol Port Settings IxEthDB APIInitialization User-Defined Field Feature SetAdditional Database Features IxEthDB Feature Set FCS Appending Dependencies on IxEthAcc ConfigurationDatabase Clear Promiscuous-Mode Requirement 180 Document Number 252539, Revision Supported PHYs Access-Layer Components Ethernet PHY IxEthMii API PHYs Supported by IxEthMii Access-Layer Components Ethernet PHY IxEthMii API Hardware Feature Control Access-Layer Components Feature Control IxFeatureCtrl API Bits Description Using the Product ID-Related FunctionsAccess-Layer Components Feature Control IxFeatureCtrl API Product ID Values Feature Control Register Values Sheet 1 Using the Feature Control Register Functions Software Configuration Feature Control Register Values Sheet 2Component Check by Other APIs Document Number 252539, Revision 187 188 Document Number 252539, Revision Access-Layer Components HSS-Access IxHssAcc API Access-Layer Components HSS-Access IxHssAcc API Features IxHssAcc API OverviewIxHssAcc Interfaces Access-Layer Components HSS-Access IxHssAcc API Intel X S cale C ore HSS and Hdlc Theory and Coprocessor Operation HSS Output Clock Jitter and Error Characterization HSS Tx Clock Output frequencies and PPM ErrorHSS Tx Freq Pj Max ns Cj Max ns Aj Max ns Actual Frame Length µs Jitter DefinitionsHSS Frame Output Characterization Jitter Type Jitter Definition High-Level API Call Flow IxHssAcc Component Dependencies Key Assumptions IxHssAccPortInit HSS Port Initialization Details 198 Document Number 252539, Revision Channelized Connect and Enable HSS Channelized OperationIxHssAccChanConnect 200 Document Number 252539, Revision Channelized Connect Channelized Tx/Rx Methods Polled CallBack Channelized Transmit and Receive IxHssAccPktPortConnect Packetized Connect and EnableHSS Packetized Operation Channelized Disconnect Document Number 252539, Revision 205 Packetized Connect Packetized Tx Document Number 252539, Revision 207 Packetized Transmit Packetized Rx Document Number 252539, Revision 209 Packetized Receive Packetized Disconnect 13.6.5 56-Kbps, Packetized Raw ModeData Flow in Packetized Service Buffer Allocation Data-Flow Overview 212 Document Number 252539, Revision HSS Packetized Receive Buffering HSS Packetized Transmit Buffering Data Flow in Channelized Service Document Number 252539, Revision 215 HSS Channelized Receive Operation HSS Channelized Transmit Operation 218 Document Number 252539, Revision Access-Layer Components NPE-Downloader IxNpeDl API Microcode ImagesLoading NPE Microcode from a File Versus Loaded from Memory NPE Image Compatibility Access-Layer Components NPE-Downloader IxNpeDl APIStandard Usage Example NPE Microcode Library Customization Image Name Description NPE-A Images NPE-C Images Sheet 1 NPE-B Images Custom Usage Example IxNpeDl UninitializationNPE-C Images Sheet 2 Deprecated APIs Access-Layer Components NPE Message Handler IxNpeMh API Polled Operation Access-Layer Components NPE Message Handler IxNpeMh APIInitializing the IxNpeMh Interrupt-Driven Operation Sending an NPE Message Uninitializing IxNpeMh IxNpeMh Sending an NPE Message with ResponseClient Customer / Demo Code IxNpeMh Client Customer / Demo Code Receiving Unsolicited Messages from NPE to Software Client IxNpeMh Component Dependencies 232 Document Number 252539, Revision Access-Layer Components Parity Error Notifier IxParityENAcc IntroductionBackground Scrubbing/Memory Scrub Network Processing Engines Expansion Bus Controller Switching Coprocessor in NPE B SwcpAHB Queue Manager AQM DDR Sdram Memory Controller Unit MCU Secondary Effects of Parity Interrupts Parity Error InterruptsInterrupt Bit Default Priority Software Interrupt Prioritization Features Feature Hardware Component Software Support RecoverableIxParityENAcc API Details IxParityENAcc API Usage Scenarios IxParityENAcc Dependency Diagram Parity Error Notification Sequence Summary Parity Error Notification Scenario Interrupt Bit Source API Invoked by Parity Error Interrupt Deassertion Conditions Sheet 1 Parity Error Interrupt Deassertion Conditions Sheet 2 Summary Parity Error Recovery Scenario Parity Error Notification Detailed Scenarios Summary Parity Error Prevention Scenario Data Abort with No Parity Error Data Abort followed by Unrelated Parity Error Notification Data Abort Caused by Parity Error Data Abort with both Related and Unrelated Parity Errors Access-Layer Components Performance Profiling IxPerfProfAcc Intel XScale Core PMU Counter Buffer Overflow Internal Bus PMU Idle-Cycle Counter Utilities ‘Xcycle’ IxPerfProfAcc Dependencies Interrupt Handling Threading Using the API Event and Clock Counting API Usage for Intel XScale Core PMU 254 Document Number 252539, Revision Display Performance Counters Time-Based Sampling Display Clock Counter Iii. Print out the first five elements Event-Based Sampling 258 Document Number 252539, Revision C0112788 No lower symbol found. Module kernel Using Intel XScale Core PMU to Determine Cache Efficiency Internal Bus PMU IxPerfProfAccBusPmuStart Perform the same calculation for the rest of the PECs Xcycle Idlecycle Counter Display Xcycle Measurement Access-Layer Components Queue Manager IxQMgr API Access-Layer Components Queue Manager IxQMgr API Features and Hardware Interface Document Number 252539, Revision 267 Attribute Description Values Configuration ValuesAQM Configuration Attributes Dispatcher Dispatcher Modes 270 Document Number 252539, Revision AQM Dispatcher in Context of a Polling Mechanism Livelock Prevention Document Number 252539, Revision 273 274 Document Number 252539, Revision IxSspAcc API Details Access-Layer Components Synchronous Serial Port IxSspAcc IxSspAcc Dependencies Interrupt Mode IxSspAcc API Usage ModelsInitialization and General Data Model 278 Document Number 252539, Revision Interrupt Scenario Polling Mode Init Transmit Receive 282 Document Number 252539, Revision Access-Layer Components Time Sync IxTimeSyncAcc API Access-Layer Components Time Sync IxTimeSyncAcc API Ieee 1588 PTP Protocol OverviewSynchronization Sequence Overview Ieee 1588 Hardware Assist Block Detailed Information Block Diagram of Intel IXP46X Network Processor IPv6 and VLAN-Tagged Ethernet Frames Hardware Feature Options Default State Additional Hardware Information IxTimeSyncAcc API DetailsIxTimeSyncAcc Ieee 1588 PTP Client Application Document Number 252539, Revision 289 Interrupt Mode Operations IxTimeSyncAcc API Usage ScenariosPolling for Transmit and Receive Timestamps Interrupt Servicing of Target Time Reached Condition Polled Mode Operations Polling for Auxiliary Snapshot Values Interface Description Access-Layer Components UART-Access IxUARTAcc API Fifo Versus Polled Mode Access-Layer Components UART-Access IxUARTAcc APIUart / OS Dependencies Uart Services Models 296 Document Number 252539, Revision USB Controller Background Access-Layer Components USB Access ixUSB API SOF Token Packet Format Access-Layer Components USB Access ixUSB APIIN, OUT, and Setup Token Packet Format Packet Formats Bits 023 Bytes Transaction FormatsData Packet Format Handshake Packet Format Action Token Packet Data Packet Bulk Transaction FormatsIsochronous Transaction Formats Action Token Packet Data Packet Handshake Packet Interrupt Transaction Formats Control Write SetupControl Transaction Formats, Set-Up Stage Control Transaction Formats IxUSB Setup Requests API interfaces Available for Access LayerIxUSB API Interfaces Request Name Host-Device Request Summary Sheet 1 Host-Device Request Summary Sheet 2 Configuration IxUSB Endpoint Stall Feature IxUSB Send and Receive RequestsFrame Synchronization Stall on OUT Transactions IxUSB Error Handling Error due to unknown reasons Detailed Error Codes USB Dependencies USB Data Flow Codelets ATM Codelet IxAtmCodeletCodelets Ethernet AAL-5 Codelet IxEthAal5App Crypto Access Codelet IxCryptoAccCodeletDMA Access Codelet IxDmaAccCodelet Ethernet Access Codelet IxEthAccCodelet Parity Error Notifier Codelet IxParityENAccCodelet HSS Access Codelet IxHssAccCodelet Performance Profiling Codelet IxPerfProfAccCodelet Time Sync Codelet IxTimeSyncAccCodeletUSB Rndis Codelet IxUSBRNDIS Operating System Abstraction Layer Osal Osal Architecture Operating System Abstraction Layer Osal Buffer Management Module OS-Independent Core ModuleOS-Dependent Module Core Module Osal Library Structure Backward Compatibility ModuleBuffer Translation Module Document Number 252539, Revision 317 C lu d e Core Module Osal Modules and Related Interfaces Osal Core Interface Sheet 1 IPC Osal Core Interface Sheet 2 Thread Buffer Management Module 24.6.3 I/O Memory and Endianness Support ModuleOsal Buffer Management Interface Osal I/O Memory and Endianness Interface Sheet 1 Ixosalmmapvirttophys Osal I/O Memory and Endianness Interface Sheet 2 Supporting a New OS Example 1. Global Memory Map Definitions Supporting New Platforms Ixstaticmap Adsl Driver Device SupportAdsl Driver Overview Adsl Line Open/Close Overview Adsl API Example of Adsl Line Open Call Sequence Limitations and Constraints 26.3 I2C Driver API Details 2C Driver IxI2cDrv I2C Driver IxI2cDrv 2C Driver IxI2cDrv Arbitration Loss Error Initialization Bus ErrorMaster-Interrupt Mode 26.4 I2C Driver API Usage Models I2C Driver IxI2cDrv Slave-Interrupt Mode Slave-Polling ModeSupport Functions Example Sequence Flows for Slave Mode Sequence Flow Diagram for Slave Transmit in Interrupt Mode Sequence Flow Diagram for Slave Receive in Polling Mode Sequence Flow Diagram for Slave Transmit in Polling Mode 26.4.3 I2C Using Gpio Versus Dedicated I2C Hardware 340 Document Number 252539, Revision Endianness in Intel IXP400 Software Basics of EndiannessEndianness in Intel IXP400 Software Nature of Endianness Hardware or Software? Endianness When Memory is Shared Software Considerations and Implications Coding Pitfalls Little-Endian/Big-EndianCasting a Pointer Between Types of Different Sizes Here is what the macro ntohl looks like in actual code Network Stacks and Protocols Avoid Best Practices in Coding of Endian-IndependenceMacro Examples Endian Conversion Macro Source Code 346 Document Number 252539, Revision Document Number 252539, Revision 347 April Reasons for Choosing a Particular LE Coherency Mode Supporting Little-Endian Mode Silicon Endianness Controls Hardware Switches MMU Intel XScale Core Endianness Mode Forcebyteswap Bit Little-Endian Data Coherence Enable/DisableMMU P-Attribute Bit Byteswapen Bit Endian Hardware Summary Silicon VersionsPCI Bus Swap Summary of Silicon Controls Part Number Brief Description IXP46X network processors A-0 stepping APB Peripherals April 2005 Ethernet Access Component IxEthAcc NPE Downloader IxNpeDlNPE Message Handler IxNpeMh Ixosalmbuf Data Payload Data Plane One Half-Word-Aligned Ethernet Frame LE Address Coherent Intel XScale Core Read of IP Header LE Data Coherent Ethernet Access MIB Statistics Learning Database FunctionIntel IXP400 Software IxEthAcc and IxEthDB Summary 27.5.4 PCI Intel IXP400 Software OS AbstractionATM and HSS #defines VxWorks* ConsiderationsIntel IXP400 Software Macros Endian Conversion Macros VxWorks* Data Coherent Swap Code Software Versions Intel IXP400 Software VersionsIntel IXP400 Software Version Little-Endian Support Yes/No