cpu/mpc5xxx/fec.c

/*
 * (C) Copyright 2003
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * This file is based on mpc4200fec.c,
 * (C) Copyright Motorola, Inc., 2000
 */

#include <common.h>
#include <mpc5xxx.h>
#include <malloc.h>
#include <net.h>
#include <miiphy.h>
#include "sdma.h"
#include "fec.h"

#define DEBUG	0x8

#if (CONFIG_COMMANDS & CFG_CMD_NET) && defined(CONFIG_NET_MULTI) && \
	defined(CONFIG_MPC5XXX_FEC)

#if (DEBUG & 0x60)
static void tfifo_print(mpc5xxx_fec_priv *fec);
static void rfifo_print(mpc5xxx_fec_priv *fec);
#endif /* DEBUG */

#if (DEBUG & 0x40)
static uint32 local_crc32(char *string, unsigned int crc_value, int len);
#endif

/********************************************************************/
static int mpc5xxx_fec_rbd_init(mpc5xxx_fec_priv *fec)
{
	int ix;
	char *data;

	/*
	 * the receive ring is located right after the transmit one
	 */
	for (ix = 0; ix < FEC_RBD_NUM; ix++) {
		data = (char *)malloc(FEC_MAX_PKT_SIZE);
		if (data == NULL) {
			printf ("RBD INIT FAILED\n");
			return -1;
		}
		fec->rbdBase[ix].status = FEC_RBD_EMPTY;
		fec->rbdBase[ix].dataLength = 0;
		fec->rbdBase[ix].dataPointer = (uint32)data;
	}

	/*
	 * have the last RBD to close the ring
	 */
	fec->rbdBase[ix - 1].status |= FEC_RBD_WRAP;
	fec->rbdIndex = 0;

	return 0;
}

/********************************************************************/
static void mpc5xxx_fec_tbd_init(mpc5xxx_fec_priv *fec)
{
	int ix;

	for (ix = 0; ix < FEC_TBD_NUM; ix++) {
		fec->tbdBase[ix].status = 0;
	}

	/*
	 * Have the last TBD to close the ring
	 */
	fec->tbdBase[ix - 1].status |= FEC_TBD_WRAP;

	/*
	 * Initialize some indices
	 */
	fec->tbdIndex = 0;
	fec->usedTbdIndex = 0;
	fec->cleanTbdNum = FEC_TBD_NUM;
}

/********************************************************************/
static void mpc5xxx_fec_rbd_clean(mpc5xxx_fec_priv *fec, FEC_RBD * pRbd)
{
	/*
	 * Reset buffer descriptor as empty
	 */
	if ((fec->rbdIndex) == (FEC_RBD_NUM - 1))
		pRbd->status = (FEC_RBD_WRAP | FEC_RBD_EMPTY);
	else
		pRbd->status = FEC_RBD_EMPTY;

	pRbd->dataLength = 0;

	/*
	 * Now, we have an empty RxBD, restart the SmartDMA receive task
	 */
	SDMA_TASK_ENABLE(FEC_RECV_TASK_NO);

	/*
	 * Increment BD count
	 */
	fec->rbdIndex = (fec->rbdIndex + 1) % FEC_RBD_NUM;
}

/********************************************************************/
static void mpc5xxx_fec_tbd_scrub(mpc5xxx_fec_priv *fec)
{
	FEC_TBD *pUsedTbd;

#if (DEBUG & 0x1)
	printf ("tbd_scrub: fec->cleanTbdNum = %d, fec->usedTbdIndex = %d\n",
		fec->cleanTbdNum, fec->usedTbdIndex);
#endif

	/*
	 * process all the consumed TBDs
	 */
	while (fec->cleanTbdNum < FEC_TBD_NUM) {
		pUsedTbd = &fec->tbdBase[fec->usedTbdIndex];
		if (pUsedTbd->status & FEC_TBD_READY) {
#if (DEBUG & 0x20)
			printf("Cannot clean TBD %d, in use\n", fec->cleanTbdNum);
#endif
			return;
		}

		/*
		 * clean this buffer descriptor
		 */
		if (fec->usedTbdIndex == (FEC_TBD_NUM - 1))
			pUsedTbd->status = FEC_TBD_WRAP;
		else
			pUsedTbd->status = 0;

		/*
		 * update some indeces for a correct handling of the TBD ring
		 */
		fec->cleanTbdNum++;
		fec->usedTbdIndex = (fec->usedTbdIndex + 1) % FEC_TBD_NUM;
	}
}

/********************************************************************/
static void mpc5xxx_fec_set_hwaddr(mpc5xxx_fec_priv *fec, char *mac)
{
	uint8 currByte;			/* byte for which to compute the CRC */
	int byte;			/* loop - counter */
	int bit;			/* loop - counter */
	uint32 crc = 0xffffffff;	/* initial value */

	/*
	 * The algorithm used is the following:
	 * we loop on each of the six bytes of the provided address,
	 * and we compute the CRC by left-shifting the previous
	 * value by one position, so that each bit in the current
	 * byte of the address may contribute the calculation. If
	 * the latter and the MSB in the CRC are different, then
	 * the CRC value so computed is also ex-ored with the
	 * "polynomium generator". The current byte of the address
	 * is also shifted right by one bit at each iteration.
	 * This is because the CRC generatore in hardware is implemented
	 * as a shift-register with as many ex-ores as the radixes
	 * in the polynomium. This suggests that we represent the
	 * polynomiumm itself as a 32-bit constant.
	 */
	for (byte = 0; byte < 6; byte++) {
		currByte = mac[byte];
		for (bit = 0; bit < 8; bit++) {
			if ((currByte & 0x01) ^ (crc & 0x01)) {
				crc >>= 1;
				crc = crc ^ 0xedb88320;
			} else {
				crc >>= 1;
			}
			currByte >>= 1;
		}
	}

	crc = crc >> 26;

	/*
	 * Set individual hash table register
	 */
	if (crc >= 32) {
		fec->eth->iaddr1 = (1 << (crc - 32));
		fec->eth->iaddr2 = 0;
	} else {
		fec->eth->iaddr1 = 0;
		fec->eth->iaddr2 = (1 << crc);
	}

	/*
	 * Set physical address
	 */
	fec->eth->paddr1 = (mac[0] << 24) + (mac[1] << 16) + (mac[2] << 8) + mac[3];
	fec->eth->paddr2 = (mac[4] << 24) + (mac[5] << 16) + 0x8808;
}

/********************************************************************/
static int mpc5xxx_fec_init(struct eth_device *dev, bd_t * bis)
{
	mpc5xxx_fec_priv *fec = (mpc5xxx_fec_priv *)dev->priv;
	struct mpc5xxx_sdma *sdma = (struct mpc5xxx_sdma *)MPC5XXX_SDMA;
	const uint8 phyAddr = 0;	/* Only one PHY */

#if (DEBUG & 0x1)
	printf ("mpc5xxx_fec_init... Begin\n");
#endif

	/*
	 * Initialize RxBD/TxBD rings
	 */
	mpc5xxx_fec_rbd_init(fec);
	mpc5xxx_fec_tbd_init(fec);

	/*
	 * Initialize GPIO pins
	 */
	if (fec->xcv_type == SEVENWIRE) {
		/*  10MBit with 7-wire operation */
		*(vu_long *)MPC5XXX_GPS_PORT_CONFIG |= 0x00020000;
	} else {
		/* 100MBit with MD operation */
		*(vu_long *)MPC5XXX_GPS_PORT_CONFIG |= 0x00050000;
	}

	/*
	 * Clear FEC-Lite interrupt event register(IEVENT)
	 */
	fec->eth->ievent = 0xffffffff;

	/*
	 * Set interrupt mask register
	 */
	fec->eth->imask = 0x00000000;

	/*
	 * Set FEC-Lite receive control register(R_CNTRL):
	 */
	if (fec->xcv_type == SEVENWIRE) {
		/*
		 * Frame length=1518; 7-wire mode
		 */
		fec->eth->r_cntrl = 0x05ee0020;	/*0x05ee0000;FIXME */
	} else {
		/*
		 * Frame length=1518; MII mode;
		 */
		fec->eth->r_cntrl = 0x05ee0024;	/*0x05ee0004;FIXME */
	}

	if (fec->xcv_type == SEVENWIRE) {
		/*
		 * Set FEC-Lite transmit control register(X_CNTRL):
		 */
		/*fec->eth->x_cntrl = 0x00000002; */  /* half-duplex, heartbeat */
		fec->eth->x_cntrl = 0x00000000;	/* half-duplex, heartbeat disabled */
	} else {
		/*fec->eth->x_cntrl = 0x00000006; */  /* full-duplex, heartbeat */
		fec->eth->x_cntrl = 0x00000004;	/* full-duplex, heartbeat disabled */

		/*
		 * Set MII_SPEED = (1/(mii_speed * 2)) * System Clock(25Mhz)
		 * and do not drop the Preamble.
		 */
		fec->eth->mii_speed = (0x5 << 1);	/* No MII for 7-wire mode */
	}

	/*
	 * Set Opcode/Pause Duration Register
	 */
	fec->eth->op_pause = 0x00010020;	/*FIXME0xffff0020; */

	/*
	 * Set Rx FIFO alarm and granularity value
	 */
	fec->eth->rfifo_cntrl = 0x0c000000;
	fec->eth->rfifo_alarm = 0x0000030c;
#if (DEBUG & 0x22)
	if (fec->eth->rfifo_status & 0x00700000 ) {
		printf("mpc5xxx_fec_init() RFIFO error\n");
	}
#endif

	/*
	 * Set Tx FIFO granularity value
	 */
	fec->eth->tfifo_cntrl = 0x0c000000;
#if (DEBUG & 0x2)
	printf("tfifo_status: 0x%08x\n", fec->eth->tfifo_status);
	printf("tfifo_alarm: 0x%08x\n", fec->eth->tfifo_alarm);
#endif

	/*
	 * Set transmit fifo watermark register(X_WMRK), default = 64
	 */
	fec->eth->tfifo_alarm = 0x00000080;
	fec->eth->x_wmrk = 0x2;

	/*
	 * Set individual address filter for unicast address
	 * and set physical address registers.
	 */
	mpc5xxx_fec_set_hwaddr(fec, dev->enetaddr);

	/*
	 * Set multicast address filter
	 */
	fec->eth->gaddr1 = 0x00000000;
	fec->eth->gaddr2 = 0x00000000;

	/*
	 * Turn ON cheater FSM: ????
	 */
	fec->eth->xmit_fsm = 0x03000000;

#if defined(CONFIG_MPC5200)
	/*
	 * Turn off COMM bus prefetch in the MGT5200 BestComm. It doesn't
	 * work w/ the current receive task.
	 */
	 sdma->PtdCntrl |= 0x00000001;
#endif

	/*
	 * Set priority of different initiators
	 */
	sdma->IPR0 = 7;		/* always */
	sdma->IPR3 = 6;		/* Eth RX */
	sdma->IPR4 = 5;		/* Eth Tx */

	/*
	 * Clear SmartDMA task interrupt pending bits
	 */
	SDMA_CLEAR_IEVENT(FEC_RECV_TASK_NO);

	/*
	 * Set SmartDMA intMask register to enable SmartDMA task interrupts
	 */
	SDMA_INT_ENABLE(FEC_RECV_TASK_NO);

	/*
	 * Initialize SmartDMA parameters stored in SRAM
	 */
	*(int *)FEC_TBD_BASE = (int)fec->tbdBase;
	*(int *)FEC_RBD_BASE = (int)fec->rbdBase;
	*(int *)FEC_TBD_NEXT = (int)fec->tbdBase;
	*(int *)FEC_RBD_NEXT = (int)fec->rbdBase;

	if (fec->xcv_type != SEVENWIRE) {
		/*
		 * Initialize PHY(LXT971A):
		 *
		 *   Generally, on power up, the LXT971A reads its configuration
		 *   pins to check for forced operation, If not cofigured for
		 *   forced operation, it uses auto-negotiation/parallel detection
		 *   to automatically determine line operating conditions.
		 *   If the PHY device on the other side of the link supports
		 *   auto-negotiation, the LXT971A auto-negotiates with it
		 *   using Fast Link Pulse(FLP) Bursts. If the PHY partner does not
		 *   support auto-negotiation, the LXT971A automatically detects
		 *   the presence of either link pulses(10Mbps PHY) or Idle
		 *   symbols(100Mbps) and sets its operating conditions accordingly.
		 *
		 *   When auto-negotiation is controlled by software, the following
		 *   steps are recommended.
		 *
		 * Note:
		 *   The physical address is dependent on hardware configuration.
		 *
		 */
		int timeout = 1;
		uint16 phyStatus;

		/*
		 * Reset PHY, then delay 300ns
		 */
		miiphy_write(phyAddr, 0x0, 0x8000);
		udelay(1000);

		if (fec->xcv_type == MII10) {
			/*
			 * Force 10Base-T, FDX operation
			 */
			printf("Forcing 10 Mbps ethernet link... ");
			miiphy_read(phyAddr, 0x1, &phyStatus);
			/*
			miiphy_write(fec, phyAddr, 0x0, 0x0100);
			*/
			miiphy_write(phyAddr, 0x0, 0x0180);

			timeout = 20;
			do {	/* wait for link status to go down */
				udelay(10000);
				if ((timeout--) == 0) {
#if (DEBUG & 0x2)
					printf("hmmm, should not have waited...");
#endif
					break;
				}
				miiphy_read(phyAddr, 0x1, &phyStatus);
#if (DEBUG & 0x2)
				printf("=");
#endif
			} while ((phyStatus & 0x0004));	/* !link up */

			timeout = 1000;
			do {	/* wait for link status to come back up */
				udelay(10000);
				if ((timeout--) == 0) {
					printf("failed. Link is down.\n");
					break;
				}
				miiphy_read(phyAddr, 0x1, &phyStatus);
#if (DEBUG & 0x2)
				printf("+");
#endif
			} while (!(phyStatus & 0x0004));	/* !link up */

			printf ("done.\n");
		} else {	/* MII100 */
			/*
			 * Set the auto-negotiation advertisement register bits
			 */
			miiphy_write(phyAddr, 0x4, 0x01e1);

			/*
			 * Set MDIO bit 0.12 = 1(&& bit 0.9=1?) to enable auto-negotiation
			 */
			miiphy_write(phyAddr, 0x0, 0x1200);

			/*
			 * Wait for AN completion
			 */
			timeout = 5000;
			do {
				udelay(1000);

				if ((timeout--) == 0) {
#if (DEBUG & 0x2)
					printf("PHY auto neg 0 failed...\n");
#endif
					return -1;
				}

				if (miiphy_read(phyAddr, 0x1, &phyStatus) != 0) {
#if (DEBUG & 0x2)
					printf("PHY auto neg 1 failed 0x%04x...\n", phyStatus);
#endif
					return -1;
				}
			} while ((phyStatus & 0x0020) != 0x0020);

#if (DEBUG & 0x2)
			printf("PHY auto neg complete! \n");
#endif
		}

	}

	/*
	 * Enable FEC-Lite controller
	 */
	fec->eth->ecntrl |= 0x00000006;

	if (fec->xcv_type != SEVENWIRE) {
#if (DEBUG & 0x2)
		uint16 phyStatus, i;
		uint8 phyAddr = 0;

		for (i = 0; i < 9; i++) {
			miiphy_read(phyAddr, i, &phyStatus);
			printf("Mii reg %d: 0x%04x\n", i, phyStatus);
		}
		for (i = 16; i < 21; i++) {
			miiphy_read(phyAddr, i, &phyStatus);
			printf("Mii reg %d: 0x%04x\n", i, phyStatus);
		}
#endif
	}
	/*
	 * Enable SmartDMA receive task
	 */
	SDMA_TASK_ENABLE(FEC_RECV_TASK_NO);

#if (DEBUG & 0x1)
	printf("mpc5xxx_fec_init... Done \n");
#endif

	return 0;
}

/********************************************************************/
static void mpc5xxx_fec_halt(struct eth_device *dev)
{
	mpc5xxx_fec_priv *fec = (mpc5xxx_fec_priv *)dev->priv;
	struct mpc5xxx_sdma *sdma = (struct mpc5xxx_sdma *)MPC5XXX_SDMA;
	int counter = 0xffff;

#if (DEBUG & 0x2)
	if (fec->xcv_type != SEVENWIRE) {
		uint16 phyStatus, i;
		uint8 phyAddr = 0;

		for (i = 0; i < 9; i++) {
			miiphy_read(phyAddr, i, &phyStatus);
			printf("Mii reg %d: 0x%04x\n", i, phyStatus);
		}
		for (i = 16; i < 21; i++) {
			miiphy_read(phyAddr, i, &phyStatus);
			printf ("Mii reg %d: 0x%04x\n", i, phyStatus);
		}
	}
#endif


	/*
	 * mask FEC chip interrupts
	 */
	fec->eth->imask = 0;

	/*
	 * issue graceful stop command to the FEC transmitter if necessary
	 */
	fec->eth->x_cntrl |= 0x00000001;

	/*
	 * wait for graceful stop to register
	 */
	while ((counter--) && (!(fec->eth->ievent & 0x10000000))) ;

	SDMA_INT_DISABLE (FEC_RECV_TASK_NO);

	/*
	 * Disable SmartDMA tasks
	 */
	SDMA_TASK_DISABLE (FEC_XMIT_TASK_NO);
	SDMA_TASK_DISABLE (FEC_RECV_TASK_NO);

#if defined(CONFIG_MPC5200)
	/*
	 * Turn on COMM bus prefetch in the MGT5200 BestComm after we're
	 * done. It doesn't work w/ the current receive task.
	 */
	 sdma->PtdCntrl &= ~0x00000001;
#endif

	/*
	 * Disable the Ethernet Controller
	 */
	fec->eth->ecntrl &= 0xfffffffd;

	/*
	 * Clear FIFO status registers
	 */
	fec->eth->rfifo_status &= 0x00700000;
	fec->eth->tfifo_status &= 0x00700000;

	fec->eth->reset_cntrl = 0x01000000;

	/*
	 * Issue a reset command to the FEC chip
	 */
	fec->eth->ecntrl |= 0x1;

	/*
	 * wait at least 16 clock cycles
	 */
	udelay(10);

#if (DEBUG & 0x3)
	printf("Ethernet task stopped\n");
#endif
}

#if (DEBUG & 0x60)
/********************************************************************/

static void tfifo_print(mpc5xxx_fec_priv *fec)
{
	uint16 phyAddr = 0;
	uint16 phyStatus;

	if ((fec->eth->tfifo_lrf_ptr != fec->eth->tfifo_lwf_ptr)
		|| (fec->eth->tfifo_rdptr != fec->eth->tfifo_wrptr)) {

		miiphy_read(phyAddr, 0x1, &phyStatus);
		printf("\nphyStatus: 0x%04x\n", phyStatus);
		printf("ecntrl:   0x%08x\n", fec->eth->ecntrl);
		printf("ievent:   0x%08x\n", fec->eth->ievent);
		printf("x_status: 0x%08x\n", fec->eth->x_status);
		printf("tfifo: status  0x%08x\n", fec->eth->tfifo_status);

		printf("       control 0x%08x\n", fec->eth->tfifo_cntrl);
		printf("       lrfp    0x%08x\n", fec->eth->tfifo_lrf_ptr);
		printf("       lwfp    0x%08x\n", fec->eth->tfifo_lwf_ptr);
		printf("       alarm   0x%08x\n", fec->eth->tfifo_alarm);
		printf("       readptr 0x%08x\n", fec->eth->tfifo_rdptr);
		printf("       writptr 0x%08x\n", fec->eth->tfifo_wrptr);
	}
}

static void rfifo_print(mpc5xxx_fec_priv *fec)
{
	uint16 phyAddr = 0;
	uint16 phyStatus;

	if ((fec->eth->rfifo_lrf_ptr != fec->eth->rfifo_lwf_ptr)
		|| (fec->eth->rfifo_rdptr != fec->eth->rfifo_wrptr)) {

		miiphy_read(phyAddr, 0x1, &phyStatus);
		printf("\nphyStatus: 0x%04x\n", phyStatus);
		printf("ecntrl:   0x%08x\n", fec->eth->ecntrl);
		printf("ievent:   0x%08x\n", fec->eth->ievent);
		printf("x_status: 0x%08x\n", fec->eth->x_status);
		printf("rfifo: status  0x%08x\n", fec->eth->rfifo_status);

		printf("       control 0x%08x\n", fec->eth->rfifo_cntrl);
		printf("       lrfp    0x%08x\n", fec->eth->rfifo_lrf_ptr);
		printf("       lwfp    0x%08x\n", fec->eth->rfifo_lwf_ptr);
		printf("       alarm   0x%08x\n", fec->eth->rfifo_alarm);
		printf("       readptr 0x%08x\n", fec->eth->rfifo_rdptr);
		printf("       writptr 0x%08x\n", fec->eth->rfifo_wrptr);
	}
}
#endif /* DEBUG */

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

static int mpc5xxx_fec_send(struct eth_device *dev, volatile void *eth_data,
		int data_length)
{
	/*
	 * This routine transmits one frame.  This routine only accepts
	 * 6-byte Ethernet addresses.
	 */
	mpc5xxx_fec_priv *fec = (mpc5xxx_fec_priv *)dev->priv;
	FEC_TBD *pTbd;

#if (DEBUG & 0x20)
	printf("tbd status: 0x%04x\n", fec->tbdBase[0].status);
	tfifo_print(fec);
#endif

	/*
	 * Clear Tx BD ring at first
	 */
	mpc5xxx_fec_tbd_scrub(fec);

	/*
	 * Check for valid length of data.
	 */
	if ((data_length > 1500) || (data_length <= 0)) {
		return -1;
	}

	/*
	 * Check the number of vacant TxBDs.
	 */
	if (fec->cleanTbdNum < 1) {
#if (DEBUG & 0x20)
		printf("No available TxBDs ...\n");
#endif
		return -1;
	}

	/*
	 * Get the first TxBD to send the mac header
	 */
	pTbd = &fec->tbdBase[fec->tbdIndex];
	pTbd->dataLength = data_length;
	pTbd->dataPointer = (uint32)eth_data;
	pTbd->status |= FEC_TBD_READY;
	fec->tbdIndex = (fec->tbdIndex + 1) % FEC_TBD_NUM;

#if (DEBUG & 0x100)
	printf("SDMA_TASK_ENABLE, fec->tbdIndex = %d \n", fec->tbdIndex);
#endif

	/*
	 * Kick the MII i/f
	 */
	if (fec->xcv_type != SEVENWIRE) {
		uint16 phyStatus;
		miiphy_read(0, 0x1, &phyStatus);
	}

	/*
	 * Enable SmartDMA transmit task
	 */

#if (DEBUG & 0x20)
	tfifo_print(fec);
#endif
	SDMA_TASK_ENABLE (FEC_XMIT_TASK_NO);
#if (DEBUG & 0x20)
	tfifo_print(fec);
#endif
#if (DEBUG & 0x8)
	printf( "+" );
#endif

	fec->cleanTbdNum -= 1;

#if (DEBUG & 0x129) && (DEBUG & 0x80000000)
	printf ("smartDMA ethernet Tx task enabled\n");
#endif
	/*
	 * wait until frame is sent .
	 */
	while (pTbd->status & FEC_TBD_READY) {
		udelay(10);
#if (DEBUG & 0x8)
		printf ("TDB status = %04x\n", pTbd->status);
#endif
	}

	return 0;
}


/********************************************************************/
static int mpc5xxx_fec_recv(struct eth_device *dev)
{
	/*
	 * This command pulls one frame from the card
	 */
	mpc5xxx_fec_priv *fec = (mpc5xxx_fec_priv *)dev->priv;
	FEC_RBD *pRbd = &fec->rbdBase[fec->rbdIndex];
	unsigned long ievent;
	int frame_length;
	char *frame;

#if (DEBUG & 0x1)
	printf ("mpc5xxx_fec_recv %d Start...\n", fec->rbdIndex);
#endif
#if (DEBUG & 0x8)
	printf( "-" );
#endif

	/*
	 * Check if any critical events have happened
	 */
	ievent = fec->eth->ievent;
	fec->eth->ievent = ievent;
	if (ievent & 0x20060000) {
		/* BABT, Rx/Tx FIFO errors */
		mpc5xxx_fec_halt(dev);
		mpc5xxx_fec_init(dev, NULL);
		return 0;
	}
	if (ievent & 0x80000000) {
		/* Heartbeat error */
		fec->eth->x_cntrl |= 0x00000001;
	}
	if (ievent & 0x10000000) {
		/* Graceful stop complete */
		if (fec->eth->x_cntrl & 0x00000001) {
			mpc5xxx_fec_halt(dev);
			fec->eth->x_cntrl &= ~0x00000001;
			mpc5xxx_fec_init(dev, NULL);
		}
	}

	/*
	 * Do we have data in Rx FIFO?
	 */
	if ((pRbd->status & FEC_RBD_EMPTY) || !(pRbd->status & FEC_RBD_LAST)){
		return 0;
	}

	/*
	 * Pass the packet up only if reception was Ok
	 */
	if ((pRbd->dataLength <= 14) || (pRbd->status & FEC_RBD_ERR)) {
		mpc5xxx_fec_rbd_clean(fec, pRbd);
#if (DEBUG & 0x8)
		printf( "X0" );
#endif
		return 0;
	}

	/*
	 * Get buffer address and size
	 */
	frame = (char *)pRbd->dataPointer;
	frame_length = pRbd->dataLength;

	/*
	 * Pass the buffer to upper layers
	 */
	NetReceive(frame, frame_length);

	/*
	 * Reset buffer descriptor as empty
	 */
	mpc5xxx_fec_rbd_clean(fec, pRbd);

	return frame_length;
}


/********************************************************************/
int mpc5xxx_fec_initialize(bd_t * bis)
{
	mpc5xxx_fec_priv *fec;
	struct eth_device *dev;

	fec = (mpc5xxx_fec_priv *)malloc(sizeof(*fec));
	dev = (struct eth_device *)malloc(sizeof(*dev));

	fec->eth = (ethernet_regs *)MPC5XXX_FEC;
	fec->tbdBase = (FEC_TBD *)FEC_BD_BASE;
	fec->rbdBase = (FEC_RBD *)(FEC_BD_BASE + FEC_TBD_NUM * sizeof(FEC_TBD));
#ifdef CONFIG_ICECUBE
	fec->xcv_type = MII100;
#endif

	dev->priv = (void *)fec;
	dev->iobase = MPC5XXX_FEC;
	dev->init = mpc5xxx_fec_init;
	dev->halt = mpc5xxx_fec_halt;
	dev->send = mpc5xxx_fec_send;
	dev->recv = mpc5xxx_fec_recv;

	eth_register(dev);

	return 1;
}

/* MII-interface related functions */
/********************************************************************/
int miiphy_read(uint8 phyAddr, uint8 regAddr, uint16 * retVal)
{
	ethernet_regs *eth = (ethernet_regs *)MPC5XXX_FEC;
	uint32 reg;		/* convenient holder for the PHY register */
	uint32 phy;		/* convenient holder for the PHY */
	int timeout = 0xffff;

	/*
	 * reading from any PHY's register is done by properly
	 * programming the FEC's MII data register.
	 */
	reg = regAddr << FEC_MII_DATA_RA_SHIFT;
	phy = phyAddr << FEC_MII_DATA_PA_SHIFT;

	eth->mii_data = (FEC_MII_DATA_ST | FEC_MII_DATA_OP_RD | FEC_MII_DATA_TA | phy | reg);

	/*
	 * wait for the related interrupt
	 */
	while ((timeout--) && (!(eth->ievent & 0x00800000))) ;

	if (timeout == 0) {
#if (DEBUG & 0x2)
		printf ("Read MDIO failed...\n");
#endif
		return -1;
	}

	/*
	 * clear mii interrupt bit
	 */
	eth->ievent = 0x00800000;

	/*
	 * it's now safe to read the PHY's register
	 */
	*retVal = (uint16) eth->mii_data;

	return 0;
}

/********************************************************************/
int miiphy_write(uint8 phyAddr, uint8 regAddr, uint16 data)
{
	ethernet_regs *eth = (ethernet_regs *)MPC5XXX_FEC;
	uint32 reg;		/* convenient holder for the PHY register */
	uint32 phy;		/* convenient holder for the PHY */
	int timeout = 0xffff;

	reg = regAddr << FEC_MII_DATA_RA_SHIFT;
	phy = phyAddr << FEC_MII_DATA_PA_SHIFT;

	eth->mii_data = (FEC_MII_DATA_ST | FEC_MII_DATA_OP_WR |
			FEC_MII_DATA_TA | phy | reg | data);

	/*
	 * wait for the MII interrupt
	 */
	while ((timeout--) && (!(eth->ievent & 0x00800000))) ;

	if (timeout == 0) {
#if (DEBUG & 0x2)
		printf ("Write MDIO failed...\n");
#endif
		return -1;
	}

	/*
	 * clear MII interrupt bit
	 */
	eth->ievent = 0x00800000;

	return 0;
}

#if (DEBUG & 0x40)
static uint32 local_crc32(char *string, unsigned int crc_value, int len)
{
	int i;
	char c;
	unsigned int crc, count;

	/*
	 * crc32 algorithm
	 */
	/*
	 * crc = 0xffffffff; * The initialized value should be 0xffffffff
	 */
	crc = crc_value;

	for (i = len; --i >= 0;) {
		c = *string++;
		for (count = 0; count < 8; count++) {
			if ((c & 0x01) ^ (crc & 0x01)) {
				crc >>= 1;
				crc = crc ^ 0xedb88320;
			} else {
				crc >>= 1;
			}
			c >>= 1;
		}
	}

	/*
	 * In big endian system, do byte swaping for crc value
	 */
	 /**/ return crc;
}
#endif	/* DEBUG */

#endif /* CONFIG_MPC5XXX_FEC */