nbuf.h

完整的Bell实验室的嵌入式文件系统TFS

/*********************************************************************
 *
 * Copyright:
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 *  You are hereby granted a copyright license to use, modify, and
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 *  retained without alteration in any modified and/or redistributed
 *  versions, and that such modified versions are clearly identified
 *  as such. No licenses are granted by implication, estoppel or
 *  otherwise under any patents or trademarks of Motorola, Inc. This 
 *  software is provided on an "AS IS" basis and without warranty.
 *
 *  To the maximum extent permitted by applicable law, MOTOROLA 
 *  DISCLAIMS ALL WARRANTIES WHETHER EXPRESS OR IMPLIED, INCLUDING 
 *  IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
 *  PURPOSE AND ANY WARRANTY AGAINST INFRINGEMENT WITH REGARD TO THE 
 *  SOFTWARE (INCLUDING ANY MODIFIED VERSIONS THEREOF) AND ANY 
 *  ACCOMPANYING WRITTEN MATERIALS.
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 *  To the maximum extent permitted by applicable law, IN NO EVENT
 *  SHALL MOTOROLA BE LIABLE FOR ANY DAMAGES WHATSOEVER (INCLUDING 
 *  WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS PROFITS, BUSINESS 
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 *  Motorola assumes no responsibility for the maintenance and support
 *  of this software
 ********************************************************************/

/*
 * File:        nbuf.h
 * Purpose:     Definitions for Network Buffer Allocation.
 *
 * Notes:       These routines implement a static buffer scheme.
 *              The buffer descriptors are as specified by the 
 *              MPC860T/MCF5272 FEC.
 *
 */

#ifndef _NBUF_H
#define _NBUF_H

/********************************************************************/

#define Rx  1
#define Tx  0

/*
 * Buffer sizes in bytes -- The following values were chosen based 
 * on TFTP maximum packet sizes.  These sizes may need to be 
 * increased to implement other protocols.
 */
#define RX_BUFFER_SIZE 576  /* must be divisible by 16 */
#define TX_BUFFER_SIZE 576

/* Number of Receive and Transmit Buffers and Buffer Descriptors */
#define NUM_RXBDS 8
#define NUM_TXBDS 8

/* Buffer Descriptor Format */
typedef struct
{
    uint16 status;  /* control and status */
    uint16 length;  /* transfer length */
    uint8  *data;   /* buffer address */
} NBUF;

/********************************************************************/

/*
 * Bit level Buffer Descriptor definitions
 */

#define TX_BD_R         0x8000
#define TX_BD_INUSE     0x4000
#define TX_BD_TO1       0x4000
#define TX_BD_W         0x2000
#define TX_BD_TO2       0x1000
#define TX_BD_L         0x0800
#define TX_BD_TC        0x0400
#define TX_BD_DEF       0x0200
#define TX_BD_HB        0x0100
#define TX_BD_LC        0x0080
#define TX_BD_RL        0x0040
#define TX_BD_UN        0x0002
#define TX_BD_CSL       0x0001

#define RX_BD_E         0x8000
#define RX_BD_INUSE     0x4000
#define RX_BD_R01       0x4000
#define RX_BD_W         0x2000
#define RX_BD_R02       0x1000
#define RX_BD_L         0x0800
#define RX_BD_M         0x0100
#define RX_BD_BC        0x0080
#define RX_BD_MC        0x0040
#define RX_BD_LG        0x0020
#define RX_BD_NO        0x0010
#define RX_BD_SH        0x0008
#define RX_BD_CR        0x0004
#define RX_BD_OV        0x0002
#define RX_BD_TR        0x0001

/*******************************************************************/

/*
 * Functions to manipulate the network buffers.
 */
void
nbuf_init (void);

uint32
nbuf_get_start(uint8);

NBUF *
nbuf_rx_allocate (void);

NBUF *
nbuf_tx_allocate (void);

void
nbuf_rx_release (NBUF *);

void
nbuf_tx_release (NBUF *);

int
nbuf_rx_next_ready(void);

void
nbuf_tx_swap(NBUF **, NBUF **);

/********************************************************************/

#endif  /* _NBUF_H */