nbuf.h

MCS-51的一个Free小型操作系统,在KeilC中下编译工作

/*
 * Network buffer code based on the MCF523x examples from Freescale.
 *
 * Freescale explicitly grants the redistribution and modification
 * of these source files. The complete licensing information is
 * available in the file LICENSE_FREESCALE.TXT.
 *
 * Modifications Copyright (c) 2006 Christian Walter <[e-mail]>
 *
 * File: $Id: nbuf.h,v 1.3 2006/09/24 22:50:23 wolti Exp $
 */

#ifndef _NBUF_H
#define _NBUF_H

/* ------------------------ Defines --------------------------------------- */

#ifdef __GNUC__
#define ATTR_FECMEM             \
    __attribute__((section(".nbuf"),aligned(16)))
#endif

#define NBUF_RX                 ( 1 )
#define NBUF_TX                 ( 0 )

/* We set the receiver buffers to the maximum size the FEC supports ( See
 * MCF5235 reference manual 19.2.5.1.2 - Driver/DMA Operation with Receive
 * BDs). This gives us the benefit that any frame fits into one buffer. A
 * maximum size of 2047 is guaranteed by the FEC and 2048 is therefore a
 * safe value.
 * Note: The value MUST be dividable by 16!
 */
#define RX_BUFFER_SIZE          ( 2048 )

/* Size of the transmit buffers. If you set this value to small all frames
 * greater than this size will be dropped. The value 1520 was choosen because
 * it is bigger than the FEC MTU (1518) and is dividable by 16.
 * Note: The value MUST be dividable by 16! */
#define TX_BUFFER_SIZE          ( 1520 )

/* Number of Receive and Transmit Buffers and Buffer Descriptors */
#define NUM_RXBDS               ( 2 )
#define NUM_TXBDS               ( 2 )

/* ------------------------ Defines ( Buffer Descriptor Flags )------------ */

#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 )

/* ------------------------ Type definitions ------------------------------ */
typedef struct
{
    uint16          status;     /* control and status */
    uint16          length;     /* transfer length */
    uint8          *data;       /* buffer address */
} nbuf_t;

/* ------------------------ Prototypes ------------------------------------ */

void            nbuf_init( void );
uint32          nbuf_get_start( uint8 );
nbuf_t         *nbuf_rx_allocate( void );
nbuf_t         *nbuf_tx_allocate( void );
void            nbuf_rx_release( nbuf_t * );
void            nbuf_tx_release( nbuf_t * );
int             nbuf_rx_next_ready( void );

#endif