NET: add ENC28J60 driver using SPI framework

V3: further refinements:
- use priv member instead of container method
- allow setting of MAC address by write_hwaddr method
- avoid shutting down link between commands

Signed-off-by: Reinhard Meyer <u-boot@emk-elektronik.de>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>

1 files changed, 978 insertions, 0 deletions

diff --git a/drivers/net/enc28j60.c b/drivers/net/enc28j60.c
new file mode 100644
index 0000000..6c161b6
--- /dev/null
+++ b/drivers/net/enc28j60.c
@@ -0,0 +1,978 @@
+/*
+ * (C) Copyright 2010
+ * Reinhard Meyer, EMK Elektronik, reinhard.meyer@emk-elektronik.de
+ * Martin Krause, Martin.Krause@tqs.de
+ * reworked original 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 <common.h>
+#include <net.h>
+#include <spi.h>
+#include <malloc.h>
+#include <netdev.h>
+#include <miiphy.h>
+#include "enc28j60.h"
+
+/*
+ * IMPORTANT: spi_claim_bus() and spi_release_bus()
+ * are called at begin and end of each of the following functions:
+ * enc_miiphy_read(), enc_miiphy_write(), enc_write_hwaddr(),
+ * enc_init(), enc_recv(), enc_send(), enc_halt()
+ * ALL other functions assume that the bus has already been claimed!
+ * Since NetReceive() might call enc_send() in return, the bus must be
+ * released, NetReceive() called and claimed again.
+ */
+
+/*
+ * Controller memory layout.
+ * We only allow 1 frame for transmission and reserve the rest
+ * for reception to handle as many broadcast packets as possible.
+ * Also use the memory from 0x0000 for receiver buffer. See errata pt. 5
+ * 0x0000 - 0x19ff 6656 bytes receive buffer
+ * 0x1a00 - 0x1fff 1536 bytes transmit buffer =
+ * control(1)+frame(1518)+status(7)+reserve(10).
+ */
+#define ENC_RX_BUF_START	0x0000
+#define ENC_RX_BUF_END		0x19ff
+#define ENC_TX_BUF_START	0x1a00
+#define ENC_TX_BUF_END		0x1fff
+#define ENC_MAX_FRM_LEN		1518
+#define RX_RESET_COUNTER	1000
+
+/*
+ * For non data transfer functions, like phy read/write, set hwaddr, init
+ * we do not need a full, time consuming init including link ready wait.
+ * This enum helps to bring the chip through the minimum necessary inits.
+ */
+enum enc_initstate {none=0, setupdone, linkready};
+typedef struct enc_device {
+	struct eth_device	*dev;	/* back pointer */
+	struct spi_slave	*slave;
+	int			rx_reset_counter;
+	u16			next_pointer;
+	u8			bank;	/* current bank in enc28j60 */
+	enum enc_initstate	initstate;
+} enc_dev_t;
+
+/*
+ * enc_bset:		set bits in a common register
+ * enc_bclr:		clear bits in a common register
+ *
+ * making the reg parameter u8 will give a compile time warning if the
+ * functions are called with a register not accessible in all Banks
+ */
+static void enc_bset(enc_dev_t *enc, const u8 reg, const u8 data)
+{
+	u8 dout[2];
+
+	dout[0] = CMD_BFS(reg);
+	dout[1] = data;
+	spi_xfer(enc->slave, 2 * 8, dout, NULL,
+		SPI_XFER_BEGIN | SPI_XFER_END);
+}
+
+static void enc_bclr(enc_dev_t *enc, const u8 reg, const u8 data)
+{
+	u8 dout[2];
+
+	dout[0] = CMD_BFC(reg);
+	dout[1] = data;
+	spi_xfer(enc->slave, 2 * 8, dout, NULL,
+		SPI_XFER_BEGIN | SPI_XFER_END);
+}
+
+/*
+ * high byte of the register contains bank number:
+ * 0: no bank switch necessary
+ * 1: switch to bank 0
+ * 2: switch to bank 1
+ * 3: switch to bank 2
+ * 4: switch to bank 3
+ */
+static void enc_set_bank(enc_dev_t *enc, const u16 reg)
+{
+	u8 newbank = reg >> 8;
+
+	if (newbank == 0 || newbank == enc->bank)
+		return;
+	switch (newbank) {
+	case 1:
+		enc_bclr(enc, CTL_REG_ECON1,
+			ENC_ECON1_BSEL0 | ENC_ECON1_BSEL1);
+		break;
+	case 2:
+		enc_bset(enc, CTL_REG_ECON1, ENC_ECON1_BSEL0);
+		enc_bclr(enc, CTL_REG_ECON1, ENC_ECON1_BSEL1);
+		break;
+	case 3:
+		enc_bclr(enc, CTL_REG_ECON1, ENC_ECON1_BSEL0);
+		enc_bset(enc, CTL_REG_ECON1, ENC_ECON1_BSEL1);
+		break;
+	case 4:
+		enc_bset(enc, CTL_REG_ECON1,
+			ENC_ECON1_BSEL0 | ENC_ECON1_BSEL1);
+		break;
+	}
+	enc->bank = newbank;
+}
+
+/*
+ * local functions to access SPI
+ *
+ * reg: register inside ENC28J60
+ * data: 8/16 bits to write
+ * c: number of retries
+ *
+ * enc_r8:		read 8 bits
+ * enc_r16:		read 16 bits
+ * enc_w8:		write 8 bits
+ * enc_w16:		write 16 bits
+ * enc_w8_retry:	write 8 bits, verify and retry
+ * enc_rbuf:		read from ENC28J60 into buffer
+ * enc_wbuf:		write from buffer into ENC28J60
+ */
+
+/*
+ * MAC and MII registers need a 3 byte SPI transfer to read,
+ * all other registers need a 2 byte SPI transfer.
+ */
+static int enc_reg2nbytes(const u16 reg)
+{
+	/* check if MAC or MII register */
+	return ((reg >= CTL_REG_MACON1 && reg <= CTL_REG_MIRDH) ||
+		(reg >= CTL_REG_MAADR1 && reg <= CTL_REG_MAADR4) ||
+		(reg == CTL_REG_MISTAT)) ? 3 : 2;
+}
+
+/*
+ * Read a byte register
+ */
+static u8 enc_r8(enc_dev_t *enc, const u16 reg)
+{
+	u8 dout[3];
+	u8 din[3];
+	int nbytes = enc_reg2nbytes(reg);
+
+	enc_set_bank(enc, reg);
+	dout[0] = CMD_RCR(reg);
+	spi_xfer(enc->slave, nbytes * 8, dout, din,
+		SPI_XFER_BEGIN | SPI_XFER_END);
+	return din[nbytes-1];
+}
+
+/*
+ * Read a L/H register pair and return a word.
+ * Must be called with the L register's address.
+ */
+static u16 enc_r16(enc_dev_t *enc, const u16 reg)
+{
+	u8 dout[3];
+	u8 din[3];
+	u16 result;
+	int nbytes = enc_reg2nbytes(reg);
+
+	enc_set_bank(enc, reg);
+	dout[0] = CMD_RCR(reg);
+	spi_xfer(enc->slave, nbytes * 8, dout, din,
+		SPI_XFER_BEGIN | SPI_XFER_END);
+	result = din[nbytes-1];
+	dout[0]++; /* next register */
+	spi_xfer(enc->slave, nbytes * 8, dout, din,
+		SPI_XFER_BEGIN | SPI_XFER_END);
+	result |= din[nbytes-1] << 8;
+	return result;
+}
+
+/*
+ * Write a byte register
+ */
+static void enc_w8(enc_dev_t *enc, const u16 reg, const u8 data)
+{
+	u8 dout[2];
+
+	enc_set_bank(enc, reg);
+	dout[0] = CMD_WCR(reg);
+	dout[1] = data;
+	spi_xfer(enc->slave, 2 * 8, dout, NULL,
+		SPI_XFER_BEGIN | SPI_XFER_END);
+}
+
+/*
+ * Write a L/H register pair.
+ * Must be called with the L register's address.
+ */
+static void enc_w16(enc_dev_t *enc, const u16 reg, const u16 data)
+{
+	u8 dout[2];
+
+	enc_set_bank(enc, reg);
+	dout[0] = CMD_WCR(reg);
+	dout[1] = data;
+	spi_xfer(enc->slave, 2 * 8, dout, NULL,
+		SPI_XFER_BEGIN | SPI_XFER_END);
+	dout[0]++; /* next register */
+	dout[1] = data >> 8;
+	spi_xfer(enc->slave, 2 * 8, dout, NULL,
+		SPI_XFER_BEGIN | SPI_XFER_END);
+}
+
+/*
+ * Write a byte register, verify and retry
+ */
+static void enc_w8_retry(enc_dev_t *enc, const u16 reg, const u8 data, const int c)
+{
+	u8 dout[2];
+	u8 readback;
+	int i;
+
+	enc_set_bank(enc, reg);
+	for (i = 0; i < c; i++) {
+		dout[0] = CMD_WCR(reg);
+		dout[1] = data;
+		spi_xfer(enc->slave, 2 * 8, dout, NULL,
+			SPI_XFER_BEGIN | SPI_XFER_END);
+		readback = enc_r8(enc, reg);
+		if (readback == data)
+			break;
+		/* wait 1ms */
+		udelay(1000);
+	}
+	if (i == c) {
+		printf("%s: write reg 0x%03x failed\n", enc->dev->name, reg);
+	}
+}
+
+/*
+ * Read ENC RAM into buffer
+ */
+static void enc_rbuf(enc_dev_t *enc, const u16 length, u8 *buf)
+{
+	u8 dout[1];
+
+	dout[0] = CMD_RBM;
+	spi_xfer(enc->slave, 8, dout, NULL, SPI_XFER_BEGIN);
+	spi_xfer(enc->slave, length * 8, NULL, buf, SPI_XFER_END);
+#ifdef DEBUG
+	puts("Rx:\n");
+	print_buffer(0, buf, 1, length, 0);
+#endif
+}
+
+/*
+ * Write buffer into ENC RAM
+ */
+static void enc_wbuf(enc_dev_t *enc, const u16 length, const u8 *buf, const u8 control)
+{
+	u8 dout[2];
+	dout[0] = CMD_WBM;
+	dout[1] = control;
+	spi_xfer(enc->slave, 2 * 8, dout, NULL, SPI_XFER_BEGIN);
+	spi_xfer(enc->slave, length * 8, buf, NULL, SPI_XFER_END);
+#ifdef DEBUG
+	puts("Tx:\n");
+	print_buffer(0, buf, 1, length, 0);
+#endif
+}
+
+/*
+ * Try to claim the SPI bus.
+ * Print error message on failure.
+ */
+static int enc_claim_bus(enc_dev_t *enc)
+{
+	int rc = spi_claim_bus(enc->slave);
+	if (rc)
+		printf("%s: failed to claim SPI bus\n", enc->dev->name);
+	return rc;
+}
+
+/*
+ * Release previously claimed SPI bus.
+ * This function is mainly for symmetry to enc_claim_bus().
+ * Let the toolchain decide to inline it...
+ */
+static void enc_release_bus(enc_dev_t *enc)
+{
+	spi_release_bus(enc->slave);
+}
+
+/*
+ * Read PHY register
+ */
+static u16 phy_read(enc_dev_t *enc, const u8 addr)
+{
+	uint64_t etime;
+	u8 status;
+
+	enc_w8(enc, CTL_REG_MIREGADR, addr);
+	enc_w8(enc, CTL_REG_MICMD, ENC_MICMD_MIIRD);
+	/* 1 second timeout - only happens on hardware problem */
+	etime = get_ticks() + get_tbclk();
+	/* poll MISTAT.BUSY bit until operation is complete */
+	do
+	{
+		status = enc_r8(enc, CTL_REG_MISTAT);
+	} while (get_ticks() <= etime && (status & ENC_MISTAT_BUSY));
+	if (status & ENC_MISTAT_BUSY) {
+		printf("%s: timeout reading phy\n", enc->dev->name);
+		return 0;
+	}
+	enc_w8(enc, CTL_REG_MICMD, 0);
+	return enc_r16(enc, CTL_REG_MIRDL);
+}
+
+/*
+ * Write PHY register
+ */
+static void phy_write(enc_dev_t *enc, const u8 addr, const u16 data)
+{
+	uint64_t etime;
+	u8 status;
+
+	enc_w8(enc, CTL_REG_MIREGADR, addr);
+	enc_w16(enc, CTL_REG_MIWRL, data);
+	/* 1 second timeout - only happens on hardware problem */
+	etime = get_ticks() + get_tbclk();
+	/* poll MISTAT.BUSY bit until operation is complete */
+	do
+	{
+		status = enc_r8(enc, CTL_REG_MISTAT);
+	} while (get_ticks() <= etime && (status & ENC_MISTAT_BUSY));
+	if (status & ENC_MISTAT_BUSY) {
+		printf("%s: timeout writing phy\n", enc->dev->name);
+		return;
+	}
+}
+
+/*
+ * Verify link status, wait if necessary
+ *
+ * Note: with a 10 MBit/s only PHY there is no autonegotiation possible,
+ * half/full duplex is a pure setup matter. For the time being, this driver
+ * will setup in half duplex mode only.
+ */
+static int enc_phy_link_wait(enc_dev_t *enc)
+{
+	u16 status;
+	int duplex;
+	uint64_t etime;
+
+#ifdef CONFIG_ENC_SILENTLINK
+	/* check if we have a link, then just return */
+	status = phy_read(enc, PHY_REG_PHSTAT1);
+	if (status & ENC_PHSTAT1_LLSTAT)
+		return 0;
+#endif
+
+	/* wait for link with 1 second timeout */
+	etime = get_ticks() + get_tbclk();
+	while (get_ticks() <= etime) {
+		status = phy_read(enc, PHY_REG_PHSTAT1);
+		if (status & ENC_PHSTAT1_LLSTAT) {
+			/* now we have a link */
+			status = phy_read(enc, PHY_REG_PHSTAT2);
+			duplex = (status & ENC_PHSTAT2_DPXSTAT) ? 1 : 0;
+			printf("%s: link up, 10Mbps %s-duplex\n",
+				enc->dev->name, duplex ? "full" : "half");
+			return 0;
+		}
+		udelay(1000);
+	}
+
+	/* timeout occured */
+	printf("%s: link down\n", enc->dev->name);
+	return 1;
+}
+
+/*
+ * This function resets the receiver only.
+ */
+static void enc_reset_rx(enc_dev_t *enc)
+{
+	u8 econ1;
+
+	econ1 = enc_r8(enc, CTL_REG_ECON1);
+	if ((econ1 & ENC_ECON1_RXRST) == 0) {
+		enc_bset(enc, CTL_REG_ECON1, ENC_ECON1_RXRST);
+		enc->rx_reset_counter = RX_RESET_COUNTER;
+	}
+}
+
+/*
+ * Reset receiver and reenable it.
+ */
+static void enc_reset_rx_call(enc_dev_t *enc)
+{
+	enc_bclr(enc, CTL_REG_ECON1, ENC_ECON1_RXRST);
+	enc_bset(enc, CTL_REG_ECON1, ENC_ECON1_RXEN);
+}
+
+/*
+ * Copy a packet from the receive ring and forward it to
+ * the protocol stack.
+ */
+static void enc_receive(enc_dev_t *enc)
+{
+	u8 *packet = (u8 *)NetRxPackets[0];
+	u16 pkt_len;
+	u16 copy_len;
+	u16 status;
+	u8 eir_reg;
+	u8 pkt_cnt = 0;
+	u16 rxbuf_rdpt;
+	u8 hbuf[6];
+
+	enc_w16(enc, CTL_REG_ERDPTL, enc->next_pointer);
+	do {
+		enc_rbuf(enc, 6, hbuf);
+		enc->next_pointer = hbuf[0] | (hbuf[1] << 8);
+		pkt_len = hbuf[2] | (hbuf[3] << 8);
+		status = hbuf[4] | (hbuf[5] << 8);
+		debug("next_pointer=$%04x pkt_len=%u status=$%04x\n",
+			enc->next_pointer, pkt_len, status);
+		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;
+		/* check if next pointer is resonable */
+		if (enc->next_pointer >= ENC_TX_BUF_START)
+			copy_len = 0;
+		if (copy_len > 0) {
+			enc_rbuf(enc, copy_len, packet);
+		}
+		/* advance read pointer to next pointer */
+		enc_w16(enc, CTL_REG_ERDPTL, enc->next_pointer);
+		/* decrease packet counter */
+		enc_bset(enc, CTL_REG_ECON2, ENC_ECON2_PKTDEC);
+		/*
+		 * Only odd values should be written to ERXRDPTL,
+		 * see errata B4 pt.13
+		 */
+		rxbuf_rdpt = enc->next_pointer - 1;
+		if ((rxbuf_rdpt < enc_r16(enc, CTL_REG_ERXSTL)) ||
+			(rxbuf_rdpt > enc_r16(enc, CTL_REG_ERXNDL))) {
+			enc_w16(enc, CTL_REG_ERXRDPTL,
+				enc_r16(enc, CTL_REG_ERXNDL));
+		} else {
+			enc_w16(enc, CTL_REG_ERXRDPTL, rxbuf_rdpt);
+		}
+		/* read pktcnt */
+		pkt_cnt = enc_r8(enc, CTL_REG_EPKTCNT);
+		if (copy_len == 0) {
+			eir_reg = enc_r8(enc, CTL_REG_EIR);
+			enc_reset_rx(enc);
+			printf("%s: receive copy_len=0\n", enc->dev->name);
+			continue;
+		}
+		/*
+		 * Because NetReceive() might call enc_send(), we need to
+		 * release the SPI bus, call NetReceive(), reclaim the bus
+		 */
+		enc_release_bus(enc);
+		NetReceive(packet, pkt_len);
+		if (enc_claim_bus(enc))
+			return;
+		eir_reg = enc_r8(enc, CTL_REG_EIR);
+	} while (pkt_cnt);
+	/* Use EPKTCNT not EIR.PKTIF flag, see errata pt. 6 */
+}
+
+/*
+ * Poll for completely received packets.
+ */
+static void enc_poll(enc_dev_t *enc)
+{
+	u8 eir_reg;
+	u8 estat_reg;
+	u8 pkt_cnt;
+
+#ifdef CONFIG_USE_IRQ
+	/* clear global interrupt enable bit in enc28j60 */
+	enc_bclr(enc, CTL_REG_EIE, ENC_EIE_INTIE);
+#endif
+	estat_reg = enc_r8(enc, CTL_REG_ESTAT);
+	eir_reg = enc_r8(enc, CTL_REG_EIR);
+	if (eir_reg & ENC_EIR_TXIF) {
+		/* clear TXIF bit in EIR */
+		enc_bclr(enc, CTL_REG_EIR, ENC_EIR_TXIF);
+	}
+	/* We have to use pktcnt and not pktif bit, see errata pt. 6 */
+	pkt_cnt = enc_r8(enc, CTL_REG_EPKTCNT);
+	if (pkt_cnt > 0) {
+		if ((eir_reg & ENC_EIR_PKTIF) == 0) {
+			debug("enc_poll: pkt cnt > 0, but pktif not set\n");
+		}
+		enc_receive(enc);
+		/*
+		 * clear PKTIF bit in EIR, this should not need to be done
+		 * but it seems like we get problems if we do not
+		 */
+		enc_bclr(enc, CTL_REG_EIR, ENC_EIR_PKTIF);
+	}
+	if (eir_reg & ENC_EIR_RXERIF) {
+		printf("%s: rx error\n", enc->dev->name);
+		enc_bclr(enc, CTL_REG_EIR, ENC_EIR_RXERIF);
+	}
+	if (eir_reg & ENC_EIR_TXERIF) {
+		printf("%s: tx error\n", enc->dev->name);
+		enc_bclr(enc, CTL_REG_EIR, ENC_EIR_TXERIF);
+	}
+#ifdef CONFIG_USE_IRQ
+	/* set global interrupt enable bit in enc28j60 */
+	enc_bset(enc, CTL_REG_EIE, ENC_EIE_INTIE);
+#endif
+}
+
+/*
+ * Completely Reset the ENC
+ */
+static void enc_reset(enc_dev_t *enc)
+{
+	u8 dout[1];
+
+	dout[0] = CMD_SRC;
+	spi_xfer(enc->slave, 8, dout, NULL,
+		SPI_XFER_BEGIN | SPI_XFER_END);
+	/* sleep 1 ms. See errata pt. 2 */
+	udelay(1000);
+}
+
+/*
+ * Initialisation data for most of the ENC registers
+ */
+static const u16 enc_initdata[] = {
+	/*
+	 * 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.
+	 */
+	CTL_REG_ERXSTL, ENC_RX_BUF_START,
+	CTL_REG_ERXSTH, ENC_RX_BUF_START >> 8,
+	CTL_REG_ERXNDL, ENC_RX_BUF_END,
+	CTL_REG_ERXNDH, ENC_RX_BUF_END >> 8,
+	CTL_REG_ERDPTL, ENC_RX_BUF_START,
+	CTL_REG_ERDPTH, ENC_RX_BUF_START >> 8,
+	/*
+	 * Set the filter to receive only good-CRC, unicast and broadcast
+	 * frames.
+	 * Note: some DHCP servers return their answers as broadcasts!
+	 * So its unwise to remove broadcast from this. This driver
+	 * might incur receiver overruns with packet loss on a broadcast
+	 * flooded network.
+	 */
+	CTL_REG_ERXFCON, ENC_RFR_BCEN | ENC_RFR_UCEN | ENC_RFR_CRCEN,
+
+	/* enable MAC to receive frames */
+	CTL_REG_MACON1,
+		ENC_MACON1_MARXEN | ENC_MACON1_TXPAUS | ENC_MACON1_RXPAUS,
+
+	/* configure pad, tx-crc and duplex */
+	CTL_REG_MACON3,
+		ENC_MACON3_PADCFG0 | ENC_MACON3_TXCRCEN |
+		ENC_MACON3_FRMLNEN,
+
+	/* Allow infinite deferals if the medium is continously busy */
+	CTL_REG_MACON4, ENC_MACON4_DEFER,
+
+	/* Late collisions occur beyond 63 bytes */
+	CTL_REG_MACLCON2, 63,
+
+	/*
+	 * Set (low byte) Non-Back-to_Back Inter-Packet Gap.
+	 * Recommended 0x12
+	 */
+	CTL_REG_MAIPGL, 0x12,
+
+	/*
+	 * Set (high byte) Non-Back-to_Back Inter-Packet Gap.
+	 * Recommended 0x0c for half-duplex. Nothing for full-duplex
+	 */
+	CTL_REG_MAIPGH, 0x0C,
+
+	/* set maximum frame length */
+	CTL_REG_MAMXFLL, ENC_MAX_FRM_LEN,
+	CTL_REG_MAMXFLH, ENC_MAX_FRM_LEN >> 8,
+
+	/*
+	 * Set MAC back-to-back inter-packet gap.
+	 * Recommended 0x12 for half duplex
+	 * and 0x15 for full duplex.
+	 */
+	CTL_REG_MABBIPG, 0x12,
+
+	/* end of table */
+	0xffff
+};
+
+/*
+ * Wait for the XTAL oscillator to become ready
+ */
+static int enc_clock_wait(enc_dev_t *enc)
+{
+	uint64_t etime;
+
+	/* one second timeout */
+	etime = get_ticks() + get_tbclk();
+
+	/*
+	 * Wait for CLKRDY to become set (i.e., check that we can
+	 * communicate with the ENC)
+	 */
+	do
+	{
+		if (enc_r8(enc, CTL_REG_ESTAT) & ENC_ESTAT_CLKRDY)
+			return 0;
+	} while (get_ticks() <= etime);
+
+	printf("%s: timeout waiting for CLKRDY\n", enc->dev->name);
+	return -1;
+}
+
+/*
+ * Write the MAC address into the ENC
+ */
+static int enc_write_macaddr(enc_dev_t *enc)
+{
+	unsigned char *p = enc->dev->enetaddr;
+
+	enc_w8_retry(enc, CTL_REG_MAADR5, *p++, 5);
+	enc_w8_retry(enc, CTL_REG_MAADR4, *p++, 5);
+	enc_w8_retry(enc, CTL_REG_MAADR3, *p++, 5);
+	enc_w8_retry(enc, CTL_REG_MAADR2, *p++, 5);
+	enc_w8_retry(enc, CTL_REG_MAADR1, *p++, 5);
+	enc_w8_retry(enc, CTL_REG_MAADR0, *p, 5);
+	return 0;
+}
+
+/*
+ * Setup most of the ENC registers
+ */
+static int enc_setup(enc_dev_t *enc)
+{
+	u16 phid1 = 0;
+	u16 phid2 = 0;
+	const u16 *tp;
+
+	/* reset enc struct values */
+	enc->next_pointer = ENC_RX_BUF_START;
+	enc->rx_reset_counter = RX_RESET_COUNTER;
+	enc->bank = 0xff;	/* invalidate current bank in enc28j60 */
+
+	/* verify PHY identification */
+	phid1 = phy_read(enc, PHY_REG_PHID1);
+	phid2 = phy_read(enc, PHY_REG_PHID2) & ENC_PHID2_MASK;
+	if (phid1 != ENC_PHID1_VALUE || phid2 != ENC_PHID2_VALUE) {
+		printf("%s: failed to identify PHY. Found %04x:%04x\n",
+			enc->dev->name, phid1, phid2);
+		return -1;
+	}
+
+	/* now program registers */
+	for (tp = enc_initdata; *tp != 0xffff; tp += 2)
+		enc_w8_retry(enc, tp[0], tp[1], 10);
+
+	/*
+	 * Prevent automatic loopback of data beeing transmitted by setting
+	 * ENC_PHCON2_HDLDIS
+	 */
+	phy_write(enc, PHY_REG_PHCON2, (1<<8));
+
+	/*
+	 * LEDs configuration
+	 * LEDA: LACFG = 0100 -> display link status
+	 * LEDB: LBCFG = 0111 -> display TX & RX activity
+	 * STRCH = 1 -> LED pulses
+	 */
+	phy_write(enc, PHY_REG_PHLCON, 0x0472);
+
+	/* Reset PDPXMD-bit => half duplex */
+	phy_write(enc, PHY_REG_PHCON1, 0);
+
+#ifdef CONFIG_USE_IRQ
+	/* enable interrupts */
+	enc_bset(enc, CTL_REG_EIE, ENC_EIE_PKTIE);
+	enc_bset(enc, CTL_REG_EIE, ENC_EIE_TXIE);
+	enc_bset(enc, CTL_REG_EIE, ENC_EIE_RXERIE);
+	enc_bset(enc, CTL_REG_EIE, ENC_EIE_TXERIE);
+	enc_bset(enc, CTL_REG_EIE, ENC_EIE_INTIE);
+#endif
+
+	return 0;
+}
+
+/*
+ * Check if ENC has been initialized.
+ * If not, try to initialize it.
+ * Remember initialized state in struct.
+ */
+static int enc_initcheck(enc_dev_t *enc, const enum enc_initstate requiredstate)
+{
+	if (enc->initstate >= requiredstate)
+		return 0;
+
+	if (enc->initstate < setupdone) {
+		/* Initialize the ENC only */
+		enc_reset(enc);
+		/* if any of functions fails, skip the rest and return an error */
+		if (enc_clock_wait(enc) || enc_setup(enc) || enc_write_macaddr(enc)) {
+			return -1;
+		}
+		enc->initstate = setupdone;
+	}
+	/* if that's all we need, return here */
+	if (enc->initstate >= requiredstate)
+		return 0;
+
+	/* now wait for link ready condition */
+	if (enc_phy_link_wait(enc)) {
+		return -1;
+	}
+	enc->initstate = linkready;
+	return 0;
+}
+
+#if defined(CONFIG_CMD_MII)
+/*
+ * Read a PHY register.
+ *
+ * This function is registered with miiphy_register().
+ */
+int enc_miiphy_read(const char *devname, u8 phy_adr, u8 reg, u16 *value)
+{
+	struct eth_device *dev = eth_get_dev_by_name(devname);
+	enc_dev_t *enc;
+
+	if (!dev || phy_adr != 0)
+		return -1;
+
+	enc = dev->priv;
+	if (enc_claim_bus(enc))
+		return -1;
+	if (enc_initcheck(enc, setupdone)) {
+		enc_release_bus(enc);
+		return -1;
+	}
+	*value = phy_read(enc, reg);
+	enc_release_bus(enc);
+	return 0;
+}
+
+/*
+ * Write a PHY register.
+ *
+ * This function is registered with miiphy_register().
+ */
+int enc_miiphy_write(const char *devname, u8 phy_adr, u8 reg, u16 value)
+{
+	struct eth_device *dev = eth_get_dev_by_name(devname);
+	enc_dev_t *enc;
+
+	if (!dev || phy_adr != 0)
+		return -1;
+
+	enc = dev->priv;
+	if (enc_claim_bus(enc))
+		return -1;
+	if (enc_initcheck(enc, setupdone)) {
+		enc_release_bus(enc);
+		return -1;
+	}
+	phy_write(enc, reg, value);
+	enc_release_bus(enc);
+	return 0;
+}
+#endif
+
+/*
+ * Write hardware (MAC) address.
+ *
+ * This function entered into eth_device structure.
+ */
+static int enc_write_hwaddr(struct eth_device *dev)
+{
+	enc_dev_t *enc = dev->priv;
+
+	if (enc_claim_bus(enc))
+		return -1;
+	if (enc_initcheck(enc, setupdone)) {
+		enc_release_bus(enc);
+		return -1;
+	}
+	enc_release_bus(enc);
+	return 0;
+}
+
+/*
+ * Initialize ENC28J60 for use.
+ *
+ * This function entered into eth_device structure.
+ */
+static int enc_init(struct eth_device *dev, bd_t *bis)
+{
+	enc_dev_t *enc = dev->priv;
+
+	if (enc_claim_bus(enc))
+		return -1;
+	if (enc_initcheck(enc, linkready)) {
+		enc_release_bus(enc);
+		return -1;
+	}
+	/* enable receive */
+	enc_bset(enc, CTL_REG_ECON1, ENC_ECON1_RXEN);
+	enc_release_bus(enc);
+	return 0;
+}
+
+/*
+ * Check for received packets.
+ *
+ * This function entered into eth_device structure.
+ */
+static int enc_recv(struct eth_device *dev)
+{
+	enc_dev_t *enc = dev->priv;
+
+	if (enc_claim_bus(enc))
+		return -1;
+	if (enc_initcheck(enc, linkready)) {
+		enc_release_bus(enc);
+		return -1;
+	}
+	/* Check for dead receiver */
+	if (enc->rx_reset_counter > 0)
+		enc->rx_reset_counter--;
+	else
+		enc_reset_rx_call(enc);
+	enc_poll(enc);
+	enc_release_bus(enc);
+	return 0;
+}
+
+/*
+ * Send a packet.
+ *
+ * This function entered into eth_device structure.
+ *
+ * Should we wait here until we have a Link? Or shall we leave that to
+ * protocol retries?
+ */
+static int enc_send(
+	struct eth_device *dev,
+	volatile void *packet,
+	int length)
+{
+	enc_dev_t *enc = dev->priv;
+
+	if (enc_claim_bus(enc))
+		return -1;
+	if (enc_initcheck(enc, linkready)) {
+		enc_release_bus(enc);
+		return -1;
+	}
+	/* setup transmit pointers */
+	enc_w16(enc, CTL_REG_EWRPTL, ENC_TX_BUF_START);
+	enc_w16(enc, CTL_REG_ETXNDL, length + ENC_TX_BUF_START);
+	enc_w16(enc, CTL_REG_ETXSTL, ENC_TX_BUF_START);
+	/* write packet to ENC */
+	enc_wbuf(enc, length, (u8 *) packet, 0x00);
+	/*
+	 * Check that the internal transmit logic has not been altered
+	 * by excessive collisions. Reset transmitter if so.
+	 * See Errata B4 12 and 14.
+	 */
+	if (enc_r8(enc, CTL_REG_EIR) & ENC_EIR_TXERIF) {
+		enc_bset(enc, CTL_REG_ECON1, ENC_ECON1_TXRST);
+		enc_bclr(enc, CTL_REG_ECON1, ENC_ECON1_TXRST);
+	}
+	enc_bclr(enc, CTL_REG_EIR, (ENC_EIR_TXERIF | ENC_EIR_TXIF));
+	/* start transmitting */
+	enc_bset(enc, CTL_REG_ECON1, ENC_ECON1_TXRTS);
+	enc_release_bus(enc);
+	return 0;
+}
+
+/*
+ * Finish use of ENC.
+ *
+ * This function entered into eth_device structure.
+ */
+static void enc_halt(struct eth_device *dev)
+{
+	enc_dev_t *enc = dev->priv;
+
+	if (enc_claim_bus(enc))
+		return;
+	/* Just disable receiver */
+	enc_bclr(enc, CTL_REG_ECON1, ENC_ECON1_RXEN);
+	enc_release_bus(enc);
+}
+
+/*
+ * This is the only exported function.
+ *
+ * It may be called several times with different bus:cs combinations.
+ */
+int enc28j60_initialize(unsigned int bus, unsigned int cs,
+	unsigned int max_hz, unsigned int mode)
+{
+	struct eth_device *dev;
+	enc_dev_t *enc;
+
+	/* try to allocate, check and clear eth_device object */
+	dev = malloc(sizeof(*dev));
+	if (!dev) {
+		return -1;
+	}
+	memset(dev, 0, sizeof(*dev));
+
+	/* try to allocate, check and clear enc_dev_t object */
+	enc = malloc(sizeof(*enc));
+	if (!enc) {
+		free(dev);
+		return -1;
+	}
+	memset(enc, 0, sizeof(*enc));
+
+	/* try to setup the SPI slave */
+	enc->slave = spi_setup_slave(bus, cs, max_hz, mode);
+	if (!enc->slave) {
+		printf("enc28j60: invalid SPI device %i:%i\n", bus, cs);
+		free(enc);
+		free(dev);
+		return -1;
+	}
+
+	enc->dev = dev;
+	/* now fill the eth_device object */
+	dev->priv = enc;
+	dev->init = enc_init;
+	dev->halt = enc_halt;
+	dev->send = enc_send;
+	dev->recv = enc_recv;
+	dev->write_hwaddr = enc_write_hwaddr;
+	sprintf(dev->name, "enc%i.%i", bus, cs);
+	eth_register(dev);
+#if defined(CONFIG_CMD_MII)
+	miiphy_register(dev->name, enc_miiphy_read, enc_miiphy_write);
+#endif
+	return 0;
+}