nbuf.c

eCos操作系统源码

//==========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
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//==========================================================================

#include <cyg/devs/eth/nbuf.h>
/*
 * Functions to manipulate the network buffers.
 */

#include <cyg/hal/hal_intr.h>
#include <cyg/infra/cyg_type.h>

#include <cyg/devs/eth/if_mcf5272.h>
#include <cyg/devs/eth/nbuf.h>
#include <cyg/infra/cyg_ass.h>

/*******************************************************************************
nbuf_init() - Initalize the networ buffers.

INPUT: pBuf - Pointer to the network buffer data.
*/
void
nbuf_init (buf_info_t* pBuf)
{
	uint_t i = 0;
    uint8 *buf = (uint8*)&(pBuf->RxBuffer);
    buf = (uint8*)((((uint32)buf+15)/16)*16);

    /* Initialize RxNBUF and TxNBUF */
    pBuf->RxNBUF = (NBUF*)((((uint32)(&pBuf->nrxbuf[0])+3)/4)*4);
    pBuf->TxNBUF = (NBUF*)((((uint32)(&pBuf->ntxbuf[0])+3)/4)*4);

	/* Initialize receive descriptor ring */
	for (i = 0; i < NUM_RXBDS; i++)
	{
		pBuf->RxNBUF[i].status = RX_BD_E;
		pBuf->RxNBUF[i].length = 0;
		pBuf->RxNBUF[i].data = buf;
        buf += RX_BUFFER_SIZE;
	}
	/* Set the Wrap bit on the last one in the ring */
	pBuf->RxNBUF[NUM_RXBDS - 1].status |= RX_BD_W;

	/* Initialize transmit descriptor ring */
	for (i = 0; i < NUM_TXBDS; i++)
	{
		pBuf->TxNBUF[i].length = 0;
		pBuf->TxNBUF[i].data = 0L;
        pBuf->TxNBUF[i].status = 0;
	}
	/* Set the Wrap bit on the last one in the ring */
	pBuf->TxNBUF[NUM_TXBDS - 1].status |= TX_BD_W;

	/* Initialize the buffer descriptor indexes */
	pBuf->iTxbd = pBuf->iRxbd = 0;

    /* Intiaize the transmit key queue to zero. */
    pBuf->tq_front = pBuf->tq_rear = 0;

    // Initalize the nubmer of transmit buffer descriptors used to zero.

    pBuf->num_busy_bd = 0;
}