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Annotation of ntddk/src/comm/serial/purge.c, revision 1.1

1.1     ! root        1: /*++
        !             2: 
        !             3: Copyright (c) 1991, 1992, 1993 Microsoft Corporation
        !             4: 
        !             5: Module Name:
        !             6: 
        !             7:     purge.c
        !             8: 
        !             9: Abstract:
        !            10: 
        !            11:     This module contains the code that is very specific to purge
        !            12:     operations in the serial driver
        !            13: 
        !            14: Author:
        !            15: 
        !            16:     Anthony V. Ercolano 26-Sep-1991
        !            17: 
        !            18: Environment:
        !            19: 
        !            20:     Kernel mode
        !            21: 
        !            22: Revision History :
        !            23: 
        !            24: --*/
        !            25: 
        !            26: #include <stddef.h>
        !            27: #include "ntddk.h"
        !            28: #include "ntddser.h"
        !            29: #include "serial.h"
        !            30: #include "serialp.h"
        !            31: 
        !            32: 
        !            33: NTSTATUS
        !            34: SerialStartPurge(
        !            35:     IN PSERIAL_DEVICE_EXTENSION Extension
        !            36:     )
        !            37: 
        !            38: /*++
        !            39: 
        !            40: Routine Description:
        !            41: 
        !            42:     Depending on the mask in the current irp, purge the interrupt
        !            43:     buffer, the read queue, or the write queue, or all of the above.
        !            44: 
        !            45: Arguments:
        !            46: 
        !            47:     Extension - Pointer to the device extension.
        !            48: 
        !            49: Return Value:
        !            50: 
        !            51:     Will return STATUS_SUCCESS always.  This is reasonable
        !            52:     since the DPC completion code that calls this routine doesn't
        !            53:     care and the purge request always goes through to completion
        !            54:     once it's started.
        !            55: 
        !            56: --*/
        !            57: 
        !            58: {
        !            59: 
        !            60:     PIRP NewIrp;
        !            61: 
        !            62:     do {
        !            63: 
        !            64:         ULONG Mask;
        !            65: 
        !            66:         Mask = *((ULONG *)
        !            67:                  (Extension->CurrentPurgeIrp->AssociatedIrp.SystemBuffer));
        !            68: 
        !            69:         if (Mask & SERIAL_PURGE_TXABORT) {
        !            70: 
        !            71:             SerialKillAllReadsOrWrites(
        !            72:                 Extension->DeviceObject,
        !            73:                 &Extension->WriteQueue,
        !            74:                 &Extension->CurrentWriteIrp
        !            75:                 );
        !            76: 
        !            77:             SerialKillAllReadsOrWrites(
        !            78:                 Extension->DeviceObject,
        !            79:                 &Extension->WriteQueue,
        !            80:                 &Extension->CurrentXoffIrp
        !            81:                 );
        !            82: 
        !            83:         }
        !            84: 
        !            85:         if (Mask & SERIAL_PURGE_RXABORT) {
        !            86: 
        !            87:             SerialKillAllReadsOrWrites(
        !            88:                 Extension->DeviceObject,
        !            89:                 &Extension->ReadQueue,
        !            90:                 &Extension->CurrentReadIrp
        !            91:                 );
        !            92: 
        !            93:         }
        !            94: 
        !            95:         if (Mask & SERIAL_PURGE_RXCLEAR) {
        !            96: 
        !            97:             KIRQL OldIrql;
        !            98: 
        !            99:             //
        !           100:             // Clean out the interrupt buffer.
        !           101:             //
        !           102:             // Note that we do this under protection of the
        !           103:             // the drivers control lock so that we don't hose
        !           104:             // the pointers if there is currently a read that
        !           105:             // is reading out of the buffer.
        !           106:             //
        !           107: 
        !           108:             KeAcquireSpinLock(
        !           109:                 &Extension->ControlLock,
        !           110:                 &OldIrql
        !           111:                 );
        !           112: 
        !           113:             KeSynchronizeExecution(
        !           114:                 Extension->Interrupt,
        !           115:                 SerialPurgeInterruptBuff,
        !           116:                 Extension
        !           117:                 );
        !           118: 
        !           119:             KeReleaseSpinLock(
        !           120:                 &Extension->ControlLock,
        !           121:                 OldIrql
        !           122:                 );
        !           123: 
        !           124:         }
        !           125: 
        !           126:         Extension->CurrentPurgeIrp->IoStatus.Status = STATUS_SUCCESS;
        !           127:         Extension->CurrentPurgeIrp->IoStatus.Information = 0;
        !           128: 
        !           129:         SerialGetNextIrp(
        !           130:             &Extension->CurrentPurgeIrp,
        !           131:             &Extension->PurgeQueue,
        !           132:             &NewIrp,
        !           133:             TRUE
        !           134:             );
        !           135: 
        !           136:     } while (NewIrp);
        !           137: 
        !           138:     return STATUS_SUCCESS;
        !           139: 
        !           140: }
        !           141: 
        !           142: BOOLEAN
        !           143: SerialPurgeInterruptBuff(
        !           144:     IN PVOID Context
        !           145:     )
        !           146: 
        !           147: /*++
        !           148: 
        !           149: Routine Description:
        !           150: 
        !           151:     This routine simply resets the interrupt (typeahead) buffer.
        !           152: 
        !           153:     NOTE: This routine is being called from KeSynchronizeExecution.
        !           154: 
        !           155: Arguments:
        !           156: 
        !           157:     Context - Really a pointer to the device extension.
        !           158: 
        !           159: Return Value:
        !           160: 
        !           161:     Always false.
        !           162: 
        !           163: --*/
        !           164: 
        !           165: {
        !           166: 
        !           167:     PSERIAL_DEVICE_EXTENSION Extension = Context;
        !           168: 
        !           169:     //
        !           170:     // The typeahead buffer is by definition empty if there
        !           171:     // currently is a read owned by the isr.
        !           172:     //
        !           173: 
        !           174: 
        !           175:     if (Extension->ReadBufferBase == Extension->InterruptReadBuffer) {
        !           176: 
        !           177:         Extension->CurrentCharSlot = Extension->InterruptReadBuffer;
        !           178:         Extension->FirstReadableChar = Extension->InterruptReadBuffer;
        !           179:         Extension->LastCharSlot = Extension->InterruptReadBuffer +
        !           180:                                       (Extension->BufferSize - 1);
        !           181:         Extension->CharsInInterruptBuffer = 0;
        !           182: 
        !           183:         SerialHandleReducedIntBuffer(Extension);
        !           184: 
        !           185:     }
        !           186: 
        !           187:     return FALSE;
        !           188: 
        !           189: }

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