4Implementing the Start Section | Compaq AA-RNG2A-TE instruction

IF_DEQUEUE(&ifp->if_snd, m);

3

while (m) {

4

m_freem(m);

IF_DEQUEUE(&ifp->if_snd, m);

}

return;

}

1

2

3

4

Declares a pointer to an ether_header data structure called eh. The ether_header data structure contains information that is associated with a 10 Mb/s and 100 Mb/s Ethernet header.

If the cardout member of the el_softc data structure for this device is set to 1 (true), the user removed the PCMCIA card from the slot.

Calls the IF_DEQUEUE macro to remove an entry from the output queue. The output queue is referenced through the if_snd member of the ifnet data structure for this device. The memory buffer information that IF_DEQUEUE manipulates is specified in the instance of the mbuf data structure called m.

As long as a transmit request was dequeued from the output queue, calls m_freem( ) to free the request and IF_DEQUEUE to dequeue the next transmit request.

9.2.2Removing Packets from the Pending Queue and Preparing the Transmit Buffer

The following code shows how the el_start_locked( ) routine removes packets from the pending queue and prepares the transmit buffer:

while(1) { 1 IF_DEQUEUE(&ifp->if_snd, m); 2

if ((m) && ((m->m_pkthdr.len+8) < sc->txfree) ) { ms = m; 4

while (ms && (ms->m_len == 0)) 5

ms = ms->m_next; 6 if (ms == NULL) { 7

m_freem(m); continue;

}

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9–4Implementing the Start Section

Image 116

Compaq AA-RNG2A-TE manual 4Implementing the Start Section

Contents

December Product Version Compaq Computer Corporation Houston, TexasPage Contents Implementing the Configure Section Implementing the Autoconfiguration Support Section probe Implementing the Autoconfiguration Support Section attach Implementing the unattach Routine Implementing the Initialization Section Implementing the Start Section Implementing the ioctl Section Implementing the Reset SectionImplementing a Watchdog Section Network Device Driver Configuration Index Implementing the Interrupt Section Tables Page About This Manual Audience Scope of this Manual New and Changed Features Organization Related Documentation Examples Reader’s Comments Reference Pages Conventions That are used in driver configuration, these brackets Page Network Device Driver Environment Network Device Driver Include Files Section for a Network Driver Declarations Section for a Network Driver External and Forward Declarations Declaring softc and controller Data Structure Arrays Declaring and Initializing the driver Data Structure Defining Driver-Specific Macros 8Network Device Driver Environment Driver-Specific Macros MacroDescription Configure Section for a Network Driver Autoconfiguration Support Section for a Network DriverInitialization Section for a Network Driver Start Section for a Network Driver Reset Section for a Network Driver Watchdog Section for a Network DriverIoctl Section for a Network Driver Interrupt Section for a Network Driver 12Network Device Driver Environment Defining Device Register Offsets Interrupt and Status Register Offset Definitions Command Port Register Offset Definitions Defining Device Register Offsets Window 0 Configuration Register Offset Definitions Register Constant W0CCR Defines the offset for the resource configuration register Window 3 Configuration Register Offset Definitions Window 3 Configuration Registers Window 1 Operational Register Offset Definitions Window 1 Operational Registers 10Defining Device Register Offsets Window 4 Diagnostic Register Offset Definitions Mdncrc 12Defining Device Register Offsets Eeprom Data Structure Definition Page Defining the softc Data Structure Shows a typical softc data structure Defining Common Information 2Defining the softc Data Structure Defining the softc Data Structure Enabling Support for Enhanced Hardware Management Defining Media State Information Media state has been determined Defining the Base Register Defining Multicast Table InformationDefining the Interrupt Handler ID Defining CSR Pointer Information Defining Fifo Maintenance Information Defining Bus-Specific Information Defining the Debug Flag Defining Interrupt and Timeout StatisticsDefining the Broadcast Flag Defining Autosense Kernel Thread Context Information Defining the Polling Context Flag Defining a Copy of the w3eeprom Data Structure Declaring the Simple Lock Data Structure Implementing the Configure Section Etc/sysconfigtab database Setting Up the elconfigure Routine Following code shows how to set up the elconfigure routine 4Implementing the Configure Section Implementing the Autoconfiguration Support Section probe Implementing the elprobe Routine Setting Up the elprobe Routine Following code shows how to set up the elprobe routine Implementing the Autoconfiguration Support Section probe 4Implementing the Autoconfiguration Support Section probe Performing Bus-Specific Tasks Implementing the Autoconfiguration Support Section probe 6Implementing the Autoconfiguration Support Section probe Allocating Memory for the softc Data Structure Allocating the etherdriver Data Structure Setting Bus-Specific Data Structure Members Computing the CSR Addresses Implementing the Autoconfiguration Support Section probe 10Implementing the Autoconfiguration Support Section probe Handling First-Time Probe Operations Implementing the Autoconfiguration Support Section probe 12Implementing the Autoconfiguration Support Section probe Handling Subsequent Probe Operations Implementing the Autoconfiguration Support Section probe Registering the Interrupt Handler Implementing the Autoconfiguration Support Section probe Saving the controller and softc Data Structure Pointers Trying to Allocate Another controller Data Structure Registering the shutdown Routine Implementing the elshutdown RoutineImplementing the elautosensethread Routine 18Implementing the Autoconfiguration Support Section probe Setting Up the elautosensethread Routine Blocking Until Awakened Entering the Packet Transmit Loop Testing for the Termination FlagStarting Up Statistics Allocating Memory for a Test Packet Using the Default from the ROMSaving Counters Prior to the Transmit Operation Transmitting the Test Packet Setting the Media in the HardwareBuilding the Test Packet Setting a Timer for the Current Kernel Thread Testing for Loss of Carrier Printing Debug Information Setting Up New MediaDetermining Whether Packets Were Transmitted Successfully Establishing the Media 26Implementing the Autoconfiguration Support Section probe Implementing the Autoconfiguration Support Section attach Setting Up the elattach Routine Initializing the Media Address and Media Header Lengths Setting Up the Media 4Implementing the Autoconfiguration Support Section attach Initializing Simple Lock Information Printing a Success Message Specifying the Network Driver Interfaces Signifies that the network interface supports Setting the Baud Rate Attaching to the Packet Filter and the Network Layer Setting Network Attributes and Registering the Adapter Handling the Reinsert Operation Enabling the Interrupt Handler Starting the Polling Process Setting Up the elunattach Routine Implementing the unattach Routine Verifying That the Interface Has Shut Down Obtaining the Simple Lock and Shutting Down the Device Disabling the Interrupt Handler Terminating the Autosense Kernel Thread Unregistering the Pcmcia Event Callback Routine Stopping the Polling ProcessUnregistering the Shutdown Routine Terminating the Simple Lock Unregistering the Card from the Hardware Management Database Freeing ResourcesPage Implementing the elinit Routine Setting Up the elinit RoutineImplementing the Initialization Section Setting the IPL and Obtaining the Simple Lock Determining Whether the Pcmcia Card Is Present Releasing the Simple Lock and Resetting the IPL Implementing the elinitlocked RoutineCalling the elinitlocked Routine Returning the Status from the elinitlocked Routine Resetting the Transmitter and Receiver Clearing Interrupts Starting the Device Ensuring That the 10Base2 Transceiver Is Off Setting the LAN Media Selecting Memory Mapping Setting a LAN AttributeResetting the Transmitter and Receiver Again Setting the LAN Address Processing Special Flags Setting the Debug Flag Enabling TX and RX Marking the Device as Running Setting the Operational WindowEnabling Interrupts Starting the Autosense Kernel Thread Starting the Transmit of Pending PacketsPage Implementing the Start Section Implementing the elstart Routine Calling the elstartlocked Routine Implementing the elstartlocked Routine 4Implementing the Start Section Implementing the Start Section Transmitting the Buffer Handlelongword Accounting for Outgoing Bytes Indicating When to Start the Watchdog Routine Setting the IPL and Obtaining the Simple Lock Implementing a Watchdog Section Releasing the Simple Lock and Resetting the IPL Implementing the Reset Section Implementing the elreset Routine Implementing the elresetlocked Routine Ioctl Command Required Description For More Information Implementing the ioctl Section Setting Up the elioctl Routine Following code shows how to set up the elioctl routine Setting the IPL and Obtaining the Simple Lock Enabling Loopback Mode Siocenablback ioctl Command Disabling Loopback Mode Siocdisablback ioctl Command Setting the Local MAC Address Siocsphysaddr ioctl Command 12-6Implementing the ioctl Section Implementing the ioctl Section Determines whether the cmd argument is Siocrdctrs or Bringing Up the Device Siocsifaddr ioctl Command Network Interface Counter Types Setting the Media Speed Siocsmacspeed ioctl Command Using Currently Set Flags Siocsifflags ioctl CommandSetting the IP MTU Siocsipmtu ioctl Command Resetting the Device Siocifreset ioctl Command Setting Device Characteristics Siocifsetchar ioctl Command 12-12Implementing the ioctl Section If lockon 1 simpleunlock&sc-elsoftclock splxs Return status Page Implementing the Interrupt Section Implementing the elintr Routine Rearming the Next Timeout Reading the Interrupt Status Processing Completed Receive and Transmit Operations Acknowledging the Interrupt Transmitting Pending Frames Indicating That the Interrupt Was Serviced Implementing the elrint Routine Pulling the Packets from the Fifo Buffer Examining the First Part of the Packet Copying the Received Packet into the mbuf 13-8Implementing the Interrupt Section Discarding a Packet Implementing the eltint Routine Counting the Transmit Interrupt Managing Excessive Data Collisions Writing to the Status Register to Obtain the Next Value Implementing the elerror Routine Queuing Other Transmits Network Device Driver Configuration Page Index Index-1 Declarations section, 1-4devdriver.h header file, 1-4device Index-2 Interrupt Index-3 Interrupt handler Index-4 Packet Index-5 ROM Index-6 Transmit Index-7