path: root/drivers/enc28j60.c

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <config.h>
#include <common.h>
#ifdef CONFIG_ENC28J60
#include <net.h>
#include <asm/arch/hardware.h>
#include <asm/arch/spi.h>

/*
 * Control Registers in Bank 0
 */

#define CTL_REG_ERDPTL	 0x00
#define CTL_REG_ERDPTH	 0x01
#define CTL_REG_EWRPTL	 0x02
#define CTL_REG_EWRPTH	 0x03
#define CTL_REG_ETXSTL	 0x04
#define CTL_REG_ETXSTH	 0x05
#define CTL_REG_ETXNDL	 0x06
#define CTL_REG_ETXNDH	 0x07
#define CTL_REG_ERXSTL	 0x08
#define CTL_REG_ERXSTH	 0x09
#define CTL_REG_ERXNDL	 0x0A
#define CTL_REG_ERXNDH	 0x0B
#define CTL_REG_ERXRDPTL 0x0C
#define CTL_REG_ERXRDPTH 0x0D
#define CTL_REG_ERXWRPTL 0x0E
#define CTL_REG_ERXWRPTH 0x0F
#define CTL_REG_EDMASTL  0x10
#define CTL_REG_EDMASTH  0x11
#define CTL_REG_EDMANDL  0x12
#define CTL_REG_EDMANDH  0x13
#define CTL_REG_EDMADSTL 0x14
#define CTL_REG_EDMADSTH 0x15
#define CTL_REG_EDMACSL  0x16
#define CTL_REG_EDMACSH  0x17
/* these are common in all banks */
#define CTL_REG_EIE	 0x1B
#define CTL_REG_EIR	 0x1C
#define CTL_REG_ESTAT	 0x1D
#define CTL_REG_ECON2	 0x1E
#define CTL_REG_ECON1	 0x1F

/*
 * Control Registers in Bank 1
 */

#define CTL_REG_EHT0	0x00
#define CTL_REG_EHT1	0x01
#define CTL_REG_EHT2	0x02
#define CTL_REG_EHT3	0x03
#define CTL_REG_EHT4	0x04
#define CTL_REG_EHT5	0x05
#define CTL_REG_EHT6	0x06
#define CTL_REG_EHT7	0x07
#define CTL_REG_EPMM0	0x08
#define CTL_REG_EPMM1	0x09
#define CTL_REG_EPMM2	0x0A
#define CTL_REG_EPMM3	0x0B
#define CTL_REG_EPMM4	0x0C
#define CTL_REG_EPMM5	0x0D
#define CTL_REG_EPMM6	0x0E
#define CTL_REG_EPMM7	0x0F
#define CTL_REG_EPMCSL	0x10
#define CTL_REG_EPMCSH	0x11
#define CTL_REG_EPMOL	0x14
#define CTL_REG_EPMOH	0x15
#define CTL_REG_EWOLIE	0x16
#define CTL_REG_EWOLIR	0x17
#define CTL_REG_ERXFCON 0x18
#define CTL_REG_EPKTCNT 0x19

/*
 * Control Registers in Bank 2
 */

#define CTL_REG_MACON1	 0x00
#define CTL_REG_MACON2	 0x01
#define CTL_REG_MACON3	 0x02
#define CTL_REG_MACON4	 0x03
#define CTL_REG_MABBIPG  0x04
#define CTL_REG_MAIPGL	 0x06
#define CTL_REG_MAIPGH	 0x07
#define CTL_REG_MACLCON1 0x08
#define CTL_REG_MACLCON2 0x09
#define CTL_REG_MAMXFLL  0x0A
#define CTL_REG_MAMXFLH  0x0B
#define CTL_REG_MAPHSUP  0x0D
#define CTL_REG_MICON	 0x11
#define CTL_REG_MICMD	 0x12
#define CTL_REG_MIREGADR 0x14
#define CTL_REG_MIWRL	 0x16
#define CTL_REG_MIWRH	 0x17
#define CTL_REG_MIRDL	 0x18
#define CTL_REG_MIRDH	 0x19

/*
 * Control Registers in Bank 3
 */

#define CTL_REG_MAADR1	0x00
#define CTL_REG_MAADR0	0x01
#define CTL_REG_MAADR3	0x02
#define CTL_REG_MAADR2	0x03
#define CTL_REG_MAADR5	0x04
#define CTL_REG_MAADR4	0x05
#define CTL_REG_EBSTSD	0x06
#define CTL_REG_EBSTCON 0x07
#define CTL_REG_EBSTCSL 0x08
#define CTL_REG_EBSTCSH 0x09
#define CTL_REG_MISTAT	0x0A
#define CTL_REG_EREVID	0x12
#define CTL_REG_ECOCON	0x15
#define CTL_REG_EFLOCON 0x17
#define CTL_REG_EPAUSL	0x18
#define CTL_REG_EPAUSH	0x19


/*
 * PHY Register
 */

#define PHY_REG_PHID1 0x02
#define PHY_REG_PHID2 0x03
/* taken from the Linux driver */
#define PHY_REG_PHCON1 0x00
#define PHY_REG_PHCON2 0x10
#define PHY_REG_PHLCON 0x14

/*
 * Receive Filter Register (ERXFCON) bits
 */

#define ENC_RFR_UCEN  0x80
#define ENC_RFR_ANDOR 0x40
#define ENC_RFR_CRCEN 0x20
#define ENC_RFR_PMEN  0x10
#define ENC_RFR_MPEN  0x08
#define ENC_RFR_HTEN  0x04
#define ENC_RFR_MCEN  0x02
#define ENC_RFR_BCEN  0x01

/*
 * ECON1 Register Bits
 */

#define ENC_ECON1_TXRST  0x80
#define ENC_ECON1_RXRST  0x40
#define ENC_ECON1_DMAST  0x20
#define ENC_ECON1_CSUMEN 0x10
#define ENC_ECON1_TXRTS  0x08
#define ENC_ECON1_RXEN	 0x04
#define ENC_ECON1_BSEL1  0x02
#define ENC_ECON1_BSEL0  0x01

/*
 * ECON2 Register Bits
 */
#define ENC_ECON2_AUTOINC 0x80
#define ENC_ECON2_PKTDEC  0x40
#define ENC_ECON2_PWRSV   0x20
#define ENC_ECON2_VRPS	  0x08

/*
 * EIR Register Bits
 */
#define ENC_EIR_PKTIF  0x40
#define ENC_EIR_DMAIF  0x20
#define ENC_EIR_LINKIF 0x10
#define ENC_EIR_TXIF   0x08
#define ENC_EIR_WOLIF  0x04
#define ENC_EIR_TXERIF 0x02
#define ENC_EIR_RXERIF 0x01

/*
 * ESTAT Register Bits
 */

#define ENC_ESTAT_INT	  0x80
#define ENC_ESTAT_LATECOL 0x10
#define ENC_ESTAT_RXBUSY  0x04
#define ENC_ESTAT_TXABRT  0x02
#define ENC_ESTAT_CLKRDY  0x01

/*
 * EIE Register Bits
 */

#define ENC_EIE_INTIE  0x80
#define ENC_EIE_PKTIE  0x40
#define ENC_EIE_DMAIE  0x20
#define ENC_EIE_LINKIE 0x10
#define ENC_EIE_TXIE   0x08
#define ENC_EIE_WOLIE  0x04
#define ENC_EIE_TXERIE 0x02
#define ENC_EIE_RXERIE 0x01

/*
 * MACON1 Register Bits
 */
#define ENC_MACON1_LOOPBK  0x10
#define ENC_MACON1_TXPAUS  0x08
#define ENC_MACON1_RXPAUS  0x04
#define ENC_MACON1_PASSALL 0x02
#define ENC_MACON1_MARXEN  0x01


/*
 * MACON2 Register Bits
 */
#define ENC_MACON2_MARST   0x80
#define ENC_MACON2_RNDRST  0x40
#define ENC_MACON2_MARXRST 0x08
#define ENC_MACON2_RFUNRST 0x04
#define ENC_MACON2_MATXRST 0x02
#define ENC_MACON2_TFUNRST 0x01

/*
 * MACON3 Register Bits
 */
#define ENC_MACON3_PADCFG2 0x80
#define ENC_MACON3_PADCFG1 0x40
#define ENC_MACON3_PADCFG0 0x20
#define ENC_MACON3_TXCRCEN 0x10
#define ENC_MACON3_PHDRLEN 0x08
#define ENC_MACON3_HFRMEN  0x04
#define ENC_MACON3_FRMLNEN 0x02
#define ENC_MACON3_FULDPX  0x01

/*
 * MICMD Register Bits
 */
#define ENC_MICMD_MIISCAN 0x02
#define ENC_MICMD_MIIRD   0x01

/*
 * MISTAT Register Bits
 */
#define ENC_MISTAT_NVALID 0x04
#define ENC_MISTAT_SCAN   0x02
#define ENC_MISTAT_BUSY   0x01

/*
 * PHID1 and PHID2 values
 */
#define ENC_PHID1_VALUE 0x0083
#define ENC_PHID2_VALUE 0x1400
#define ENC_PHID2_MASK	0xFC00


#define ENC_SPI_SLAVE_CS 0x00010000	/* pin P1.16 */
#define ENC_RESET	 0x00020000	/* pin P1.17 */

#define FAILSAFE_VALUE 5000

/*
 * Controller memory layout:
 *
 * 0x0000 - 0x17ff  6k bytes receive buffer
 * 0x1800 - 0x1fff  2k bytes transmit buffer
 */
/* Use the lower memory for receiver buffer. See errata pt. 5 */
#define ENC_RX_BUF_START 0x0000
#define ENC_TX_BUF_START 0x1800
/* taken from the Linux driver */
#define ENC_RX_BUF_END   0x17ff
#define ENC_TX_BUF_END   0x1fff

/* maximum frame length */
#define ENC_MAX_FRM_LEN 1518

#define enc_enable() PUT32(IO1CLR, ENC_SPI_SLAVE_CS)
#define enc_disable() PUT32(IO1SET, ENC_SPI_SLAVE_CS)
#define enc_cfg_spi() spi_set_cfg(0, 0, 0); spi_set_clock(8);


static unsigned char encReadReg (unsigned char regNo);
static void encWriteReg (unsigned char regNo, unsigned char data);
static void encWriteRegRetry (unsigned char regNo, unsigned char data, int c);
static void encReadBuff (unsigned short length, unsigned char *pBuff);
static void encWriteBuff (unsigned short length, unsigned char *pBuff);
static void encBitSet (unsigned char regNo, unsigned char data);
static void encBitClr (unsigned char regNo, unsigned char data);
static void encReset (void);
static void encInit (unsigned char *pEthAddr);
static unsigned short phyRead (unsigned char addr);
static void phyWrite(unsigned char, unsigned short);
static void encPoll (void);
static void encRx (void);

#define m_nic_read(reg) encReadReg(reg)
#define m_nic_write(reg, data) encWriteReg(reg, data)
#define m_nic_write_retry(reg, data, count) encWriteRegRetry(reg, data, count)
#define m_nic_read_data(len, buf) encReadBuff((len), (buf))
#define m_nic_write_data(len, buf) encWriteBuff((len), (buf))

/* bit field set */
#define m_nic_bfs(reg, data) encBitSet(reg, data)

/* bit field clear */
#define m_nic_bfc(reg, data) encBitClr(reg, data)

static unsigned char bank = 0;	/* current bank in enc28j60 */
static unsigned char next_pointer_lsb;
static unsigned char next_pointer_msb;

static unsigned char buffer[ENC_MAX_FRM_LEN];
static int rxResetCounter = 0;

#define RX_RESET_COUNTER 1000;

/*-----------------------------------------------------------------------------
 * Always returns 0
 */
int eth_init (bd_t * bis)
{
	unsigned char estatVal;

	/* configure GPIO */
	(*((volatile unsigned long *) IO1DIR)) |= ENC_SPI_SLAVE_CS;
	(*((volatile unsigned long *) IO1DIR)) |= ENC_RESET;

	/* CS and RESET active low */
	PUT32 (IO1SET, ENC_SPI_SLAVE_CS);
	PUT32 (IO1SET, ENC_RESET);

	spi_init ();

	/* taken from the Linux driver - dangerous stuff here! */
	/* Wait for CLKRDY to become set (i.e., check that we can communicate with
	   the ENC) */
	do
	{
		estatVal = m_nic_read(CTL_REG_ESTAT);
	} while ((estatVal & 0x08) || (~estatVal & ENC_ESTAT_CLKRDY));

	/* initialize controller */
	encReset ();
	encInit (bis->bi_enetaddr);

	m_nic_bfs (CTL_REG_ECON1, ENC_ECON1_RXEN);	/* enable receive */

	return 0;
}

int eth_send (volatile void *packet, int length)
{
	/* check frame length, etc. */
	/* TODO: */

	/* switch to bank 0 */
	m_nic_bfc (CTL_REG_ECON1, (ENC_ECON1_BSEL1 | ENC_ECON1_BSEL0));

	/* set EWRPT */
	m_nic_write (CTL_REG_EWRPTL, (ENC_TX_BUF_START & 0xff));
	m_nic_write (CTL_REG_EWRPTH, (ENC_TX_BUF_START >> 8));

	/* set ETXND */
	m_nic_write (CTL_REG_ETXNDL, (length + ENC_TX_BUF_START) & 0xFF);
	m_nic_write (CTL_REG_ETXNDH, (length + ENC_TX_BUF_START) >> 8);

	/* set ETXST */
	m_nic_write (CTL_REG_ETXSTL, ENC_TX_BUF_START & 0xFF);
	m_nic_write (CTL_REG_ETXSTH, ENC_TX_BUF_START >> 8);

	/* write packet */
	m_nic_write_data (length, (unsigned char *) packet);

	/* taken from the Linux driver */
	/* Verify that the internal transmit logic has not been altered by excessive
	   collisions.  See Errata B4 12 and 14.
	 */
	if (m_nic_read(CTL_REG_EIR) & ENC_EIR_TXERIF) {
		m_nic_bfs(CTL_REG_ECON1, ENC_ECON1_TXRST);
		m_nic_bfc(CTL_REG_ECON1, ENC_ECON1_TXRST);
	}
	m_nic_bfc(CTL_REG_EIR, (ENC_EIR_TXERIF | ENC_EIR_TXIF));

	/* set ECON1.TXRTS */
	m_nic_bfs (CTL_REG_ECON1, ENC_ECON1_TXRTS);

	return 0;
}


/*****************************************************************************
 * This function resets the receiver only. This function may be called from
 * interrupt-context.
 */
static void encReceiverReset (void)
{
	unsigned char econ1;

	econ1 = m_nic_read (CTL_REG_ECON1);
	if ((econ1 & ENC_ECON1_RXRST) == 0) {
		m_nic_bfs (CTL_REG_ECON1, ENC_ECON1_RXRST);
		rxResetCounter = RX_RESET_COUNTER;
	}
}

/*****************************************************************************
 * receiver reset timer
 */
static void encReceiverResetCallback (void)
{
	m_nic_bfc (CTL_REG_ECON1, ENC_ECON1_RXRST);
	m_nic_bfs (CTL_REG_ECON1, ENC_ECON1_RXEN);	/* enable receive */
}

/*-----------------------------------------------------------------------------
 * Check for received packets. Call NetReceive for each packet. The return
 * value is ignored by the caller.
 */
int eth_rx (void)
{
	if (rxResetCounter > 0 && --rxResetCounter == 0) {
		encReceiverResetCallback ();
	}

	encPoll ();

	return 0;
}

void eth_halt (void)
{
	m_nic_bfc (CTL_REG_ECON1, ENC_ECON1_RXEN);	/* disable receive */
}

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

static void encPoll (void)
{
	unsigned char eir_reg;
	volatile unsigned char estat_reg;
	unsigned char pkt_cnt;

#ifdef CONFIG_USE_IRQ
	/* clear global interrupt enable bit in enc28j60 */
	m_nic_bfc (CTL_REG_EIE, ENC_EIE_INTIE);
#endif
	estat_reg = m_nic_read (CTL_REG_ESTAT);

	eir_reg = m_nic_read (CTL_REG_EIR);

	if (eir_reg & ENC_EIR_TXIF) {
		/* clear TXIF bit in EIR */
		m_nic_bfc (CTL_REG_EIR, ENC_EIR_TXIF);
	}

	/* We have to use pktcnt and not pktif bit, see errata pt. 6 */

	/* move to bank 1 */
	m_nic_bfc (CTL_REG_ECON1, ENC_ECON1_BSEL1);
	m_nic_bfs (CTL_REG_ECON1, ENC_ECON1_BSEL0);

	/* read pktcnt */
	pkt_cnt = m_nic_read (CTL_REG_EPKTCNT);

	if (pkt_cnt > 0) {
		if ((eir_reg & ENC_EIR_PKTIF) == 0) {
			/*printf("encPoll: pkt cnt > 0, but pktif not set\n"); */
		}
		encRx ();
		/* clear PKTIF bit in EIR, this should not need to be done but it
		   seems like we get problems if we do not */
		m_nic_bfc (CTL_REG_EIR, ENC_EIR_PKTIF);
	}

	if (eir_reg & ENC_EIR_RXERIF) {
		printf ("encPoll: rx error\n");
		m_nic_bfc (CTL_REG_EIR, ENC_EIR_RXERIF);
	}
	if (eir_reg & ENC_EIR_TXERIF) {
		printf ("encPoll: tx error\n");
		m_nic_bfc (CTL_REG_EIR, ENC_EIR_TXERIF);
	}

#ifdef CONFIG_USE_IRQ
	/* set global interrupt enable bit in enc28j60 */
	m_nic_bfs (CTL_REG_EIE, ENC_EIE_INTIE);
#endif
}

static void encRx (void)
{
	unsigned short pkt_len;
	unsigned short copy_len;
	unsigned short status;
	unsigned char eir_reg;
	unsigned char pkt_cnt = 0;
	unsigned short rxbuf_rdpt;

	/* switch to bank 0 */
	m_nic_bfc (CTL_REG_ECON1, (ENC_ECON1_BSEL1 | ENC_ECON1_BSEL0));

	m_nic_write (CTL_REG_ERDPTL, next_pointer_lsb);
	m_nic_write (CTL_REG_ERDPTH, next_pointer_msb);

	do {
		m_nic_read_data (6, buffer);
		next_pointer_lsb = buffer[0];
		next_pointer_msb = buffer[1];
		pkt_len = buffer[2];
		pkt_len |= (unsigned short) buffer[3] << 8;
		status = buffer[4];
		status |= (unsigned short) buffer[5] << 8;

		if (pkt_len <= ENC_MAX_FRM_LEN)
			copy_len = pkt_len;
		else
			copy_len = 0;

		if ((status & (1L << 7)) == 0) /* check Received Ok bit */
			copy_len = 0;

		/* taken from the Linux driver */
		/* check if next pointer is resonable */
		if ((((unsigned int)next_pointer_msb << 8) |
			(unsigned int)next_pointer_lsb) >= ENC_TX_BUF_START)
			copy_len = 0;

		if (copy_len > 0) {
			m_nic_read_data (copy_len, buffer);
		}

		/* advance read pointer to next pointer */
		m_nic_write (CTL_REG_ERDPTL, next_pointer_lsb);
		m_nic_write (CTL_REG_ERDPTH, next_pointer_msb);

		/* decrease packet counter */
		m_nic_bfs (CTL_REG_ECON2, ENC_ECON2_PKTDEC);

		/* taken from the Linux driver */
		/* Only odd values should be written to ERXRDPTL, see errata B4 pt.13 */		rxbuf_rdpt = (next_pointer_msb << 8 | next_pointer_lsb) - 1;
		if ((rxbuf_rdpt < (m_nic_read(CTL_REG_ERXSTH) << 8 |
				m_nic_read(CTL_REG_ERXSTL))) || (rxbuf_rdpt >
				(m_nic_read(CTL_REG_ERXNDH) << 8 |
				m_nic_read(CTL_REG_ERXNDL)))) {
			m_nic_write(CTL_REG_ERXRDPTL, m_nic_read(CTL_REG_ERXNDL));
			m_nic_write(CTL_REG_ERXRDPTH, m_nic_read(CTL_REG_ERXNDH));
		} else {
			m_nic_write(CTL_REG_ERXRDPTL, rxbuf_rdpt & 0xFF);
			m_nic_write(CTL_REG_ERXRDPTH, rxbuf_rdpt >> 8);
		}

		/* move to bank 1 */
		m_nic_bfc (CTL_REG_ECON1, ENC_ECON1_BSEL1);
		m_nic_bfs (CTL_REG_ECON1, ENC_ECON1_BSEL0);

		/* read pktcnt */
		pkt_cnt = m_nic_read (CTL_REG_EPKTCNT);

		/* switch to bank 0 */
		m_nic_bfc (CTL_REG_ECON1,
			   (ENC_ECON1_BSEL1 | ENC_ECON1_BSEL0));

		if (copy_len == 0) {
			eir_reg = m_nic_read (CTL_REG_EIR);
			encReceiverReset ();
			printf ("eth_rx: copy_len=0\n");
			continue;
		}

		NetReceive ((unsigned char *) buffer, pkt_len);

		eir_reg = m_nic_read (CTL_REG_EIR);
	} while (pkt_cnt);	/* Use EPKTCNT not EIR.PKTIF flag, see errata pt. 6 */
}

static void encWriteReg (unsigned char regNo, unsigned char data)
{
	spi_lock ();
	enc_cfg_spi ();
	enc_enable ();

	spi_write (0x40 | regNo);	/* write in regNo */
	spi_write (data);

	enc_disable ();
	enc_enable ();

	spi_write (0x1f);	/* write reg 0x1f */

	enc_disable ();
	spi_unlock ();
}

static void encWriteRegRetry (unsigned char regNo, unsigned char data, int c)
{
	unsigned char readback;
	int i;

	spi_lock ();

	for (i = 0; i < c; i++) {
		enc_cfg_spi ();
		enc_enable ();

		spi_write (0x40 | regNo);	/* write in regNo */
		spi_write (data);

		enc_disable ();
		enc_enable ();

		spi_write (0x1f);	/* write reg 0x1f */

		enc_disable ();

		spi_unlock ();	/* we must unlock spi first */

		readback = encReadReg (regNo);

		spi_lock ();

		if (readback == data)
			break;
	}
	spi_unlock ();

	if (i == c) {
		printf ("enc28j60: write reg %d failed\n", regNo);
	}
}

static unsigned char encReadReg (unsigned char regNo)
{
	unsigned char rxByte;

	spi_lock ();
	enc_cfg_spi ();
	enc_enable ();

	spi_write (0x1f);	/* read reg 0x1f */

	bank = spi_read () & 0x3;

	enc_disable ();
	enc_enable ();

	spi_write (regNo);
	rxByte = spi_read ();

	/* check if MAC or MII register */
	if (((bank == 2) && (regNo <= 0x1a)) ||
	    ((bank == 3) && (regNo <= 0x05 || regNo == 0x0a))) {
		/* ignore first byte and read another byte */
		rxByte = spi_read ();
	}

	enc_disable ();
	spi_unlock ();

	return rxByte;
}

static void encReadBuff (unsigned short length, unsigned char *pBuff)
{
	spi_lock ();
	enc_cfg_spi ();
	enc_enable ();

	spi_write (0x20 | 0x1a);	/* read buffer memory */

	while (length--) {
		if (pBuff != NULL)
			*pBuff++ = spi_read ();
		else
			spi_write (0);
	}

	enc_disable ();
	spi_unlock ();
}

static void encWriteBuff (unsigned short length, unsigned char *pBuff)
{
	spi_lock ();
	enc_cfg_spi ();
	enc_enable ();

	spi_write (0x60 | 0x1a);	/* write buffer memory */

	spi_write (0x00);	/* control byte */

	while (length--)
		spi_write (*pBuff++);

	enc_disable ();
	spi_unlock ();
}

static void encBitSet (unsigned char regNo, unsigned char data)
{
	spi_lock ();
	enc_cfg_spi ();
	enc_enable ();

	spi_write (0x80 | regNo);	/* bit field set */
	spi_write (data);

	enc_disable ();
	spi_unlock ();
}

static void encBitClr (unsigned char regNo, unsigned char data)
{
	spi_lock ();
	enc_cfg_spi ();
	enc_enable ();

	spi_write (0xA0 | regNo);	/* bit field clear */
	spi_write (data);

	enc_disable ();
	spi_unlock ();
}

static void encReset (void)
{
	spi_lock ();
	enc_cfg_spi ();
	enc_enable ();

	spi_write (0xff);	/* soft reset */

	enc_disable ();
	spi_unlock ();

	/* sleep 1 ms. See errata pt. 2 */
	udelay (1000);
}

static void encInit (unsigned char *pEthAddr)
{
	unsigned short phid1 = 0;
	unsigned short phid2 = 0;

	/* switch to bank 0 */
	m_nic_bfc (CTL_REG_ECON1, (ENC_ECON1_BSEL1 | ENC_ECON1_BSEL0));

	/*
	 * Setup the buffer space. The reset values are valid for the
	 * other pointers.
	 */
	/* We shall not write to ERXST, see errata pt. 5. Instead we
	   have to make sure that ENC_RX_BUS_START is 0. */
	m_nic_write_retry (CTL_REG_ERXSTL, (ENC_RX_BUF_START & 0xFF), 1);
	m_nic_write_retry (CTL_REG_ERXSTH, (ENC_RX_BUF_START >> 8), 1);

	/* taken from the Linux driver */
	m_nic_write_retry (CTL_REG_ERXNDL, (ENC_RX_BUF_END & 0xFF), 1);
	m_nic_write_retry (CTL_REG_ERXNDH, (ENC_RX_BUF_END >> 8), 1);

	m_nic_write_retry (CTL_REG_ERDPTL, (ENC_RX_BUF_START & 0xFF), 1);
	m_nic_write_retry (CTL_REG_ERDPTH, (ENC_RX_BUF_START >> 8), 1);

	next_pointer_lsb = (ENC_RX_BUF_START & 0xFF);
	next_pointer_msb = (ENC_RX_BUF_START >> 8);

	/* verify identification */
	phid1 = phyRead (PHY_REG_PHID1);
	phid2 = phyRead (PHY_REG_PHID2);

	if (phid1 != ENC_PHID1_VALUE
	    || (phid2 & ENC_PHID2_MASK) != ENC_PHID2_VALUE) {
		printf ("ERROR: failed to identify controller\n");
		printf ("phid1 = %x, phid2 = %x\n",
			phid1, (phid2 & ENC_PHID2_MASK));
		printf ("should be phid1 = %x, phid2 = %x\n",
			ENC_PHID1_VALUE, ENC_PHID2_VALUE);
	}

	/*
	 * --- MAC Initialization ---
	 */

	/* Pull MAC out of Reset */

	/* switch to bank 2 */
	m_nic_bfc (CTL_REG_ECON1, ENC_ECON1_BSEL0);
	m_nic_bfs (CTL_REG_ECON1, ENC_ECON1_BSEL1);

	/* enable MAC to receive frames */
	/* added some bits from the Linux driver */
	m_nic_write_retry (CTL_REG_MACON1, (ENC_MACON1_MARXEN | ENC_MACON1_TXPAUS | ENC_MACON1_RXPAUS), 10);

	/* configure pad, tx-crc and duplex */
	/* added a bit from the Linux driver */
	m_nic_write_retry (CTL_REG_MACON3,
			   (ENC_MACON3_PADCFG0 | ENC_MACON3_TXCRCEN | ENC_MACON3_FRMLNEN),
			   10);

	/* added 4 new lines from the Linux driver */
	/* Allow infinite deferals if the medium is continously busy */
	m_nic_write_retry(CTL_REG_MACON4, (1<<6) /*ENC_MACON4_DEFER*/, 10);

	/* Late collisions occur beyond 63 bytes */
	m_nic_write_retry(CTL_REG_MACLCON2, 63, 10);

	/* Set (low byte) Non-Back-to_Back Inter-Packet Gap. Recommended 0x12 */
	m_nic_write_retry(CTL_REG_MAIPGL, 0x12, 10);

	/*
	* Set (high byte) Non-Back-to_Back Inter-Packet Gap. Recommended
	* 0x0c for half-duplex. Nothing for full-duplex
	*/
	m_nic_write_retry(CTL_REG_MAIPGH, 0x0C, 10);

	/* set maximum frame length */
	m_nic_write_retry (CTL_REG_MAMXFLL, (ENC_MAX_FRM_LEN & 0xff), 10);
	m_nic_write_retry (CTL_REG_MAMXFLH, (ENC_MAX_FRM_LEN >> 8), 10);

	/*
	 * Set MAC back-to-back inter-packet gap. Recommended 0x12 for half duplex
	 * and 0x15 for full duplex.
	 */
	m_nic_write_retry (CTL_REG_MABBIPG, 0x12, 10);

	/* set MAC address */

	/* switch to bank 3 */
	m_nic_bfs (CTL_REG_ECON1, (ENC_ECON1_BSEL0 | ENC_ECON1_BSEL1));

	m_nic_write_retry (CTL_REG_MAADR0, pEthAddr[5], 1);
	m_nic_write_retry (CTL_REG_MAADR1, pEthAddr[4], 1);
	m_nic_write_retry (CTL_REG_MAADR2, pEthAddr[3], 1);
	m_nic_write_retry (CTL_REG_MAADR3, pEthAddr[2], 1);
	m_nic_write_retry (CTL_REG_MAADR4, pEthAddr[1], 1);
	m_nic_write_retry (CTL_REG_MAADR5, pEthAddr[0], 1);

	/*
	* PHY Initialization taken from the Linux driver
	 */

	/* Prevent automatic loopback of data beeing transmitted by setting
	   ENC_PHCON2_HDLDIS */
	phyWrite(PHY_REG_PHCON2, (1<<8));

	/* LEDs configuration
	 * LEDA: LACFG = 0100 -> display link status
	 * LEDB: LBCFG = 0111 -> display TX & RX activity
	 * STRCH = 1 -> LED pulses
	 */
	phyWrite(PHY_REG_PHLCON, 0x0472);

	/* Reset PDPXMD-bit => half duplex */
	phyWrite(PHY_REG_PHCON1, 0);

	/*
	 * Receive settings
	 */

#ifdef CONFIG_USE_IRQ
	/* enable interrupts */
	m_nic_bfs (CTL_REG_EIE, ENC_EIE_PKTIE);
	m_nic_bfs (CTL_REG_EIE, ENC_EIE_TXIE);
	m_nic_bfs (CTL_REG_EIE, ENC_EIE_RXERIE);
	m_nic_bfs (CTL_REG_EIE, ENC_EIE_TXERIE);
	m_nic_bfs (CTL_REG_EIE, ENC_EIE_INTIE);
#endif
}

/*****************************************************************************
 *
 * Description:
 *    Read PHY registers.
 *
 *    NOTE! This function will change to Bank 2.
 *
 * Params:
 *    [in] addr address of the register to read
 *
 * Returns:
 *    The value in the register
 */
static unsigned short phyRead (unsigned char addr)
{
	unsigned short ret = 0;

	/* move to bank 2 */
	m_nic_bfc (CTL_REG_ECON1, ENC_ECON1_BSEL0);
	m_nic_bfs (CTL_REG_ECON1, ENC_ECON1_BSEL1);

	/* write address to MIREGADR */
	m_nic_write (CTL_REG_MIREGADR, addr);

	/* set MICMD.MIIRD */
	m_nic_write (CTL_REG_MICMD, ENC_MICMD_MIIRD);

	/* taken from the Linux driver */
	/* move to bank 3 */
	m_nic_bfs(CTL_REG_ECON1, ENC_ECON1_BSEL0);
	m_nic_bfs(CTL_REG_ECON1, ENC_ECON1_BSEL1);

	/* poll MISTAT.BUSY bit until operation is complete */
	while ((m_nic_read (CTL_REG_MISTAT) & ENC_MISTAT_BUSY) != 0) {
		static int cnt = 0;

		if (cnt++ >= 1000) {
			/* GJ - this seems extremely dangerous! */
			/* printf("#"); */
			cnt = 0;
		}
	}

	/* taken from the Linux driver */
	/* move to bank 2 */
	m_nic_bfc(CTL_REG_ECON1, ENC_ECON1_BSEL0);
	m_nic_bfs(CTL_REG_ECON1, ENC_ECON1_BSEL1);

	/* clear MICMD.MIIRD */
	m_nic_write (CTL_REG_MICMD, 0);

	ret = (m_nic_read (CTL_REG_MIRDH) << 8);
	ret |= (m_nic_read (CTL_REG_MIRDL) & 0xFF);

	return ret;
}

/*****************************************************************************
 *
 * Taken from the Linux driver.
 * Description:
 * Write PHY registers.
 *
 * NOTE! This function will change to Bank 3.
 *
 * Params:
 * [in] addr address of the register to write to
 * [in] data to be written
 *
 * Returns:
 *    None
 */
static void phyWrite(unsigned char addr, unsigned short data)
{
	/* move to bank 2 */
	m_nic_bfc(CTL_REG_ECON1, ENC_ECON1_BSEL0);
	m_nic_bfs(CTL_REG_ECON1, ENC_ECON1_BSEL1);

	/* write address to MIREGADR */
	m_nic_write(CTL_REG_MIREGADR, addr);

	m_nic_write(CTL_REG_MIWRL, data & 0xff);
	m_nic_write(CTL_REG_MIWRH, data >> 8);

	/* move to bank 3 */
	m_nic_bfs(CTL_REG_ECON1, ENC_ECON1_BSEL0);
	m_nic_bfs(CTL_REG_ECON1, ENC_ECON1_BSEL1);

	/* poll MISTAT.BUSY bit until operation is complete */
	while((m_nic_read(CTL_REG_MISTAT) & ENC_MISTAT_BUSY) != 0) {
		static int cnt = 0;

		if(cnt++ >= 1000) {
			cnt = 0;
		}
	}
}

#endif /* CONFIG_ENC28J60 */