net: add ENC28J60 support

ENC28J60 is a stand-alone Ethernet controller with SPI Interface
and integrated 10BASE-T PHY.

This driver was ported from linux-3.15.

The most notable barebox driver version changes:
  * add device tree support;
  * drop netif_msg_*() debug level checking;
  * use IF_ENABLED for checking CONFIG_ENC28J60_WRITEVERIFY;
  * add mii_bus support.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 1012 insertions, 0 deletions

diff --git a/drivers/net/enc28j60.c b/drivers/net/enc28j60.c
new file mode 100644
index 0000000000..76b3df63f6
--- /dev/null
+++ b/drivers/net/enc28j60.c
@@ -0,0 +1,1012 @@
+/*
+ * Microchip ENC28J60 ethernet driver (MAC + PHY)
+ *
+ * This code was ported from linux-3.15 kernel by Antony Pavlov.
+ *
+ * Copyright (C) 2007 Eurek srl
+ * Author: Claudio Lanconelli <lanconelli.claudio@eptar.com>
+ * based on enc28j60.c written by David Anders for 2.4 kernel version
+ *
+ * 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.
+ *
+ */
+
+#include <common.h>
+#include <net.h>
+#include <malloc.h>
+#include <init.h>
+#include <driver.h>
+#include <spi/spi.h>
+#include <xfuncs.h>
+#include <errno.h>
+
+#include "enc28j60_hw.h"
+
+#define DRV_NAME	"enc28j60"
+
+#define SPI_OPLEN	1
+
+#define ENC28J60_MSG_DEFAULT	\
+	(NETIF_MSG_PROBE | NETIF_MSG_IFUP | NETIF_MSG_IFDOWN | NETIF_MSG_LINK)
+
+/* Buffer size required for the largest SPI transfer (i.e., reading a
+ * frame). */
+#define SPI_TRANSFER_BUF_LEN	(4 + MAX_FRAMELEN)
+
+/* Driver local data */
+struct enc28j60_net {
+	struct eth_device edev;
+	struct spi_device *spi;
+	u8 bank;		/* current register bank selected */
+	u16 next_pk_ptr;	/* next packet pointer within FIFO */
+	u16 max_pk_counter;	/* statistics: max packet counter */
+	u16 tx_retry_count;
+	bool hw_enable;
+	bool full_duplex;
+	int rxfilter;
+	u8 spi_transfer_buf[SPI_TRANSFER_BUF_LEN];
+	/* store MAC address here while hardware is in the reset state */
+	u8 hwaddr[ETH_ALEN];
+	struct mii_bus miibus;
+};
+
+/*
+ * SPI read buffer
+ * wait for the SPI transfer and copy received data to destination
+ */
+static int
+spi_read_buf(struct enc28j60_net *priv, int len, u8 *data)
+{
+	u8 *rx_buf = priv->spi_transfer_buf + 4;
+	u8 *tx_buf = priv->spi_transfer_buf;
+	struct spi_transfer t = {
+		.tx_buf = tx_buf,
+		.rx_buf = rx_buf,
+		.len = SPI_OPLEN + len,
+	};
+	struct spi_message msg;
+	int ret;
+
+	tx_buf[0] = ENC28J60_READ_BUF_MEM;
+	tx_buf[1] = tx_buf[2] = tx_buf[3] = 0;	/* don't care */
+
+	spi_message_init(&msg);
+	spi_message_add_tail(&t, &msg);
+	ret = spi_sync(priv->spi, &msg);
+	if (ret == 0) {
+		memcpy(data, &rx_buf[SPI_OPLEN], len);
+		ret = msg.status;
+	}
+	if (ret)
+		dev_err(&priv->edev.dev,
+			"%s() failed: ret = %d\n", __func__, ret);
+
+	return ret;
+}
+
+/*
+ * SPI write buffer
+ */
+static int spi_write_buf(struct enc28j60_net *priv, int len,
+			 const u8 *data)
+{
+	int ret;
+
+	if (len > SPI_TRANSFER_BUF_LEN - 1 || len <= 0)
+		ret = -EINVAL;
+	else {
+		priv->spi_transfer_buf[0] = ENC28J60_WRITE_BUF_MEM;
+		memcpy(&priv->spi_transfer_buf[1], data, len);
+		ret = spi_write(priv->spi, priv->spi_transfer_buf, len + 1);
+		if (ret)
+			dev_err(&priv->edev.dev,
+				"%s() failed: ret = %d\n", __func__, ret);
+	}
+	return ret;
+}
+
+/*
+ * basic SPI read operation
+ */
+static u8 spi_read_op(struct enc28j60_net *priv, u8 op,
+			   u8 addr)
+{
+	u8 tx_buf[2];
+	u8 rx_buf[4];
+	u8 val = 0;
+	int ret;
+	int slen = SPI_OPLEN;
+
+	/* do dummy read if needed */
+	if (addr & SPRD_MASK)
+		slen++;
+
+	tx_buf[0] = op | (addr & ADDR_MASK);
+	ret = spi_write_then_read(priv->spi, tx_buf, 1, rx_buf, slen);
+	if (ret)
+		dev_err(&priv->edev.dev,
+			"%s() failed: ret = %d\n", __func__, ret);
+	else
+		val = rx_buf[slen - 1];
+
+	return val;
+}
+
+/*
+ * basic SPI write operation
+ */
+static int spi_write_op(struct enc28j60_net *priv, u8 op,
+			u8 addr, u8 val)
+{
+	int ret;
+
+	priv->spi_transfer_buf[0] = op | (addr & ADDR_MASK);
+	priv->spi_transfer_buf[1] = val;
+	ret = spi_write(priv->spi, priv->spi_transfer_buf, 2);
+	if (ret)
+		dev_err(&priv->edev.dev,
+			"%s() failed: ret = %d\n", __func__, ret);
+
+	return ret;
+}
+
+static void enc28j60_soft_reset(struct enc28j60_net *priv)
+{
+	dev_dbg(&priv->edev.dev, "%s() enter\n", __func__);
+
+	spi_write_op(priv, ENC28J60_SOFT_RESET, 0, ENC28J60_SOFT_RESET);
+	/* Errata workaround #1, CLKRDY check is unreliable,
+	 * delay at least 1 mS instead */
+	udelay(2000);
+}
+
+/*
+ * select the current register bank if necessary
+ */
+static void enc28j60_set_bank(struct enc28j60_net *priv, u8 addr)
+{
+	u8 b = (addr & BANK_MASK) >> 5;
+
+	/* These registers (EIE, EIR, ESTAT, ECON2, ECON1)
+	 * are present in all banks, no need to switch bank
+	 */
+	if (addr >= EIE && addr <= ECON1)
+		return;
+
+	/* Clear or set each bank selection bit as needed */
+	if ((b & ECON1_BSEL0) != (priv->bank & ECON1_BSEL0)) {
+		if (b & ECON1_BSEL0)
+			spi_write_op(priv, ENC28J60_BIT_FIELD_SET, ECON1,
+					ECON1_BSEL0);
+		else
+			spi_write_op(priv, ENC28J60_BIT_FIELD_CLR, ECON1,
+					ECON1_BSEL0);
+	}
+	if ((b & ECON1_BSEL1) != (priv->bank & ECON1_BSEL1)) {
+		if (b & ECON1_BSEL1)
+			spi_write_op(priv, ENC28J60_BIT_FIELD_SET, ECON1,
+					ECON1_BSEL1);
+		else
+			spi_write_op(priv, ENC28J60_BIT_FIELD_CLR, ECON1,
+					ECON1_BSEL1);
+	}
+	priv->bank = b;
+}
+
+/*
+ * Register access routines through the SPI bus.
+ * Some registers can be accessed through the bit field clear and
+ * bit field set to avoid a read modify write cycle.
+ */
+
+/*
+ * Register bit field Set
+ */
+static void enc28j60_reg_bfset(struct enc28j60_net *priv,
+				      u8 addr, u8 mask)
+{
+	enc28j60_set_bank(priv, addr);
+	spi_write_op(priv, ENC28J60_BIT_FIELD_SET, addr, mask);
+}
+
+/*
+ * Register bit field Clear
+ */
+static void enc28j60_reg_bfclr(struct enc28j60_net *priv,
+				      u8 addr, u8 mask)
+{
+	enc28j60_set_bank(priv, addr);
+	spi_write_op(priv, ENC28J60_BIT_FIELD_CLR, addr, mask);
+}
+
+/*
+ * Register byte read
+ */
+static int enc28j60_regb_read(struct enc28j60_net *priv,
+				     u8 address)
+{
+	enc28j60_set_bank(priv, address);
+	return spi_read_op(priv, ENC28J60_READ_CTRL_REG, address);
+}
+
+/*
+ * Register word read
+ */
+static int enc28j60_regw_read(struct enc28j60_net *priv,
+				     u8 address)
+{
+	int rl, rh;
+
+	enc28j60_set_bank(priv, address);
+	rl = spi_read_op(priv, ENC28J60_READ_CTRL_REG, address);
+	rh = spi_read_op(priv, ENC28J60_READ_CTRL_REG, address + 1);
+
+	return (rh << 8) | rl;
+}
+
+/*
+ * Register byte write
+ */
+static void enc28j60_regb_write(struct enc28j60_net *priv,
+				       u8 address, u8 data)
+{
+	enc28j60_set_bank(priv, address);
+	spi_write_op(priv, ENC28J60_WRITE_CTRL_REG, address, data);
+}
+
+/*
+ * Register word write
+ */
+static void enc28j60_regw_write(struct enc28j60_net *priv,
+				       u8 address, u16 data)
+{
+	enc28j60_set_bank(priv, address);
+	spi_write_op(priv, ENC28J60_WRITE_CTRL_REG, address, (u8) data);
+	spi_write_op(priv, ENC28J60_WRITE_CTRL_REG, address + 1,
+		     (u8) (data >> 8));
+}
+
+/*
+ * Buffer memory read
+ * Select the starting address and execute a SPI buffer read
+ */
+static void enc28j60_mem_read(struct enc28j60_net *priv,
+				     u16 addr, int len, u8 *data)
+{
+	enc28j60_regw_write(priv, ERDPTL, addr);
+
+	if (IS_ENABLED(CONFIG_ENC28J60_WRITEVERIFY)) {
+		u16 reg;
+		reg = enc28j60_regw_read(priv, ERDPTL);
+		if (reg != addr)
+			dev_err(&priv->edev.dev, "%s() error writing ERDPT "
+				"(0x%04x - 0x%04x)\n", __func__, reg, addr);
+	}
+
+	spi_read_buf(priv, len, data);
+}
+
+/*
+ * Write packet to enc28j60 TX buffer memory
+ */
+static void
+enc28j60_packet_write(struct enc28j60_net *priv, int len, const u8 *data)
+{
+	/* Set the write pointer to start of transmit buffer area */
+	enc28j60_regw_write(priv, EWRPTL, TXSTART_INIT);
+
+	if (IS_ENABLED(CONFIG_ENC28J60_WRITEVERIFY)) {
+		u16 reg;
+		reg = enc28j60_regw_read(priv, EWRPTL);
+		if (reg != TXSTART_INIT)
+			dev_err(&priv->edev.dev,
+				"%s() ERWPT:0x%04x != 0x%04x\n",
+				__func__, reg, TXSTART_INIT);
+	}
+	/* Set the TXND pointer to correspond to the packet size given */
+	enc28j60_regw_write(priv, ETXNDL, TXSTART_INIT + len);
+	/* write per-packet control byte */
+	spi_write_op(priv, ENC28J60_WRITE_BUF_MEM, 0, 0x00);
+	dev_dbg(&priv->edev.dev,
+		"%s() after control byte ERWPT:0x%04x\n",
+		__func__, enc28j60_regw_read(priv, EWRPTL));
+	/* copy the packet into the transmit buffer */
+	spi_write_buf(priv, len, data);
+	dev_dbg(&priv->edev.dev,
+		"%s() after write packet ERWPT:0x%04x, len=%d\n",
+		 __func__, enc28j60_regw_read(priv, EWRPTL), len);
+}
+
+static int poll_ready(struct enc28j60_net *priv, u8 reg, u8 mask, u8 val)
+{
+	if ((enc28j60_regb_read(priv, reg) & mask) == val) {
+		return 0;
+	}
+
+	/* 20 msec timeout read */
+	mdelay(20);
+
+	if ((enc28j60_regb_read(priv, reg) & mask) != val) {
+		dev_err(&priv->spi->dev, "reg %02x ready timeout!\n", reg);
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+/*
+ * Wait until the PHY operation is complete.
+ */
+static int wait_phy_ready(struct enc28j60_net *priv)
+{
+	return poll_ready(priv, MISTAT, MISTAT_BUSY, 0) ? 0 : 1;
+}
+
+/*
+ * PHY register read
+ * PHY registers are not accessed directly, but through the MII
+ */
+static u16 enc28j60_phy_read(struct enc28j60_net *priv, u8 address)
+{
+	u16 ret;
+
+	/* set the PHY register address */
+	enc28j60_regb_write(priv, MIREGADR, address);
+	/* start the register read operation */
+	enc28j60_regb_write(priv, MICMD, MICMD_MIIRD);
+	/* wait until the PHY read completes */
+	wait_phy_ready(priv);
+	/* quit reading */
+	enc28j60_regb_write(priv, MICMD, 0x00);
+	/* return the data */
+	ret = enc28j60_regw_read(priv, MIRDL);
+
+	return ret;
+}
+
+static int enc28j60_phy_write(struct enc28j60_net *priv, u8 address, u16 data)
+{
+	int ret;
+
+	/* set the PHY register address */
+	enc28j60_regb_write(priv, MIREGADR, address);
+	/* write the PHY data */
+	enc28j60_regw_write(priv, MIWRL, data);
+	/* wait until the PHY write completes and return */
+	ret = wait_phy_ready(priv);
+
+	return ret;
+}
+
+/*
+ * MII-interface related functions
+ */
+static int enc28j60_miibus_read(struct mii_bus *bus, int phy_addr, int reg_addr)
+{
+	struct enc28j60_net *priv = (struct enc28j60_net *)bus->priv;
+
+	if (phy_addr == 0) {
+		return enc28j60_phy_read(priv, reg_addr);
+	}
+
+	return 0xffff;
+}
+
+static int enc28j60_miibus_write(struct mii_bus *bus, int phy_addr,
+	int reg_addr, u16 data)
+{
+	struct enc28j60_net *priv = (struct enc28j60_net *)bus->priv;
+
+	if (phy_addr == 0) {
+		enc28j60_phy_write(priv, reg_addr, data);
+	}
+
+	return 0;
+}
+
+static int enc28j60_get_ethaddr(struct eth_device *edev, unsigned char *m)
+{
+	struct enc28j60_net *priv = edev->priv;
+
+	memcpy(m, priv->hwaddr, ETH_ALEN);
+
+	dev_dbg(&edev->dev, "getting MAC address\n");
+
+	return 0;
+}
+
+/*
+ * Program the hardware MAC address from dev->dev_addr.
+ */
+static int enc28j60_set_ethaddr(struct eth_device *edev,
+					unsigned char *mac_addr)
+{
+	int ret;
+	struct enc28j60_net *priv = edev->priv;
+
+	if (!priv->hw_enable) {
+		dev_dbg(&edev->dev, "%s(): Setting MAC address\n", __func__);
+		/* NOTE: MAC address in ENC28J60 is byte-backward */
+		enc28j60_regb_write(priv, MAADR5, mac_addr[0]);
+		enc28j60_regb_write(priv, MAADR4, mac_addr[1]);
+		enc28j60_regb_write(priv, MAADR3, mac_addr[2]);
+		enc28j60_regb_write(priv, MAADR2, mac_addr[3]);
+		enc28j60_regb_write(priv, MAADR1, mac_addr[4]);
+		enc28j60_regb_write(priv, MAADR0, mac_addr[5]);
+		ret = 0;
+		memcpy(priv->hwaddr, mac_addr, ETH_ALEN);
+	} else {
+		dev_err(&edev->dev, "%s() Hardware must be disabled to set "
+			"Mac address\n", __func__);
+		ret = -EBUSY;
+	}
+
+	return ret;
+}
+
+/*
+ * Debug routine to dump useful register contents
+ */
+static inline void enc28j60_dump_regs(struct enc28j60_net *priv, const char *msg)
+{
+	dev_dbg(&priv->edev.dev, " %s\n"
+		"HwRevID: 0x%02x\n"
+		"Cntrl: ECON1 ECON2 ESTAT  EIR  EIE\n"
+		"       0x%02x  0x%02x  0x%02x  0x%02x  0x%02x\n"
+		"MAC  : MACON1 MACON3 MACON4\n"
+		"       0x%02x   0x%02x   0x%02x\n"
+		"Rx   : ERXST  ERXND  ERXWRPT ERXRDPT ERXFCON EPKTCNT MAMXFL\n"
+		"       0x%04x 0x%04x 0x%04x  0x%04x  "
+		"0x%02x    0x%02x    0x%04x\n"
+		"Tx   : ETXST  ETXND  MACLCON1 MACLCON2 MAPHSUP\n"
+		"       0x%04x 0x%04x 0x%02x     0x%02x     0x%02x\n",
+		msg, enc28j60_regb_read(priv, EREVID),
+		enc28j60_regb_read(priv, ECON1), enc28j60_regb_read(priv, ECON2),
+		enc28j60_regb_read(priv, ESTAT), enc28j60_regb_read(priv, EIR),
+		enc28j60_regb_read(priv, EIE), enc28j60_regb_read(priv, MACON1),
+		enc28j60_regb_read(priv, MACON3), enc28j60_regb_read(priv, MACON4),
+		enc28j60_regw_read(priv, ERXSTL), enc28j60_regw_read(priv, ERXNDL),
+		enc28j60_regw_read(priv, ERXWRPTL),
+		enc28j60_regw_read(priv, ERXRDPTL),
+		enc28j60_regb_read(priv, ERXFCON),
+		enc28j60_regb_read(priv, EPKTCNT),
+		enc28j60_regw_read(priv, MAMXFLL), enc28j60_regw_read(priv, ETXSTL),
+		enc28j60_regw_read(priv, ETXNDL),
+		enc28j60_regb_read(priv, MACLCON1),
+		enc28j60_regb_read(priv, MACLCON2),
+		enc28j60_regb_read(priv, MAPHSUP));
+}
+
+/*
+ * ERXRDPT need to be set always at odd addresses, refer to errata datasheet
+ */
+static u16 erxrdpt_workaround(u16 next_packet_ptr, u16 start, u16 end)
+{
+	u16 erxrdpt;
+
+	if ((next_packet_ptr - 1 < start) || (next_packet_ptr - 1 > end))
+		erxrdpt = end;
+	else
+		erxrdpt = next_packet_ptr - 1;
+
+	return erxrdpt;
+}
+
+/*
+ * Calculate wrap around when reading beyond the end of the RX buffer
+ */
+static u16 rx_packet_start(u16 ptr)
+{
+	if (ptr + RSV_SIZE > RXEND_INIT)
+		return (ptr + RSV_SIZE) - (RXEND_INIT - RXSTART_INIT + 1);
+	else
+		return ptr + RSV_SIZE;
+}
+
+static void enc28j60_rxfifo_init(struct enc28j60_net *priv, u16 start, u16 end)
+{
+	u16 erxrdpt;
+
+	if (start > 0x1FFF || end > 0x1FFF || start > end) {
+		dev_err(&priv->edev.dev,
+			"%s(%d, %d) RXFIFO bad parameters!\n",
+			__func__, start, end);
+		return;
+	}
+
+	/* set receive buffer start + end */
+	priv->next_pk_ptr = start;
+	enc28j60_regw_write(priv, ERXSTL, start);
+	erxrdpt = erxrdpt_workaround(priv->next_pk_ptr, start, end);
+	enc28j60_regw_write(priv, ERXRDPTL, erxrdpt);
+	enc28j60_regw_write(priv, ERXNDL, end);
+}
+
+static void enc28j60_txfifo_init(struct enc28j60_net *priv, u16 start, u16 end)
+{
+	if (start > 0x1FFF || end > 0x1FFF || start > end) {
+		dev_err(&priv->edev.dev,
+			"%s(%d, %d) TXFIFO bad parameters!\n",
+			__func__, start, end);
+		return;
+	}
+	/* set transmit buffer start + end */
+	enc28j60_regw_write(priv, ETXSTL, start);
+	enc28j60_regw_write(priv, ETXNDL, end);
+}
+
+/*
+ * Low power mode shrinks power consumption about 100x, so we'd like
+ * the chip to be in that mode whenever it's inactive.  (However, we
+ * can't stay in lowpower mode during suspend with WOL active.)
+ */
+static void enc28j60_lowpower(struct enc28j60_net *priv, bool is_low)
+{
+	dev_dbg(&priv->spi->dev, "%s power...\n", is_low ? "low" : "high");
+
+	if (is_low) {
+		enc28j60_reg_bfclr(priv, ECON1, ECON1_RXEN);
+		poll_ready(priv, ESTAT, ESTAT_RXBUSY, 0);
+		poll_ready(priv, ECON1, ECON1_TXRTS, 0);
+		/* ECON2_VRPS was set during initialization */
+		enc28j60_reg_bfset(priv, ECON2, ECON2_PWRSV);
+	} else {
+		enc28j60_reg_bfclr(priv, ECON2, ECON2_PWRSV);
+		poll_ready(priv, ESTAT, ESTAT_CLKRDY, ESTAT_CLKRDY);
+		/* caller sets ECON1_RXEN */
+	}
+}
+
+static int enc28j60_hw_init(struct enc28j60_net *priv)
+{
+	u8 reg;
+
+	dev_dbg(&priv->edev.dev, "%s() - %s\n", __func__,
+		priv->full_duplex ? "FullDuplex" : "HalfDuplex");
+
+	/* first reset the chip */
+	enc28j60_soft_reset(priv);
+	/* Clear ECON1 */
+	spi_write_op(priv, ENC28J60_WRITE_CTRL_REG, ECON1, 0x00);
+	priv->bank = 0;
+	priv->hw_enable = false;
+	priv->tx_retry_count = 0;
+	priv->max_pk_counter = 0;
+
+	/* enable address auto increment and voltage regulator powersave */
+	enc28j60_regb_write(priv, ECON2, ECON2_AUTOINC | ECON2_VRPS);
+
+	enc28j60_rxfifo_init(priv, RXSTART_INIT, RXEND_INIT);
+	enc28j60_txfifo_init(priv, TXSTART_INIT, TXEND_INIT);
+
+	/*
+	 * Check the RevID.
+	 * If it's 0x00 or 0xFF probably the enc28j60 is not mounted or
+	 * damaged
+	 */
+	reg = enc28j60_regb_read(priv, EREVID);
+
+	dev_dbg(&priv->edev.dev, "chip RevID: 0x%02x\n", reg);
+
+	if (reg == 0x00 || reg == 0xff) {
+		dev_err(&priv->edev.dev,
+			"%s() Invalid RevId %d\n", __func__, reg);
+		return 0;
+	}
+
+	/* default filter mode: (unicast OR broadcast) AND crc valid */
+	enc28j60_regb_write(priv, ERXFCON,
+			    ERXFCON_UCEN | ERXFCON_CRCEN | ERXFCON_BCEN);
+
+	/* enable MAC receive */
+	enc28j60_regb_write(priv, MACON1,
+			    MACON1_MARXEN | MACON1_TXPAUS | MACON1_RXPAUS);
+
+	/* enable automatic padding and CRC operations */
+	if (priv->full_duplex) {
+		enc28j60_regb_write(priv, MACON3,
+				    MACON3_PADCFG0 | MACON3_TXCRCEN |
+				    MACON3_FRMLNEN | MACON3_FULDPX);
+		/* set inter-frame gap (non-back-to-back) */
+		enc28j60_regb_write(priv, MAIPGL, 0x12);
+		/* set inter-frame gap (back-to-back) */
+		enc28j60_regb_write(priv, MABBIPG, 0x15);
+	} else {
+		enc28j60_regb_write(priv, MACON3,
+				    MACON3_PADCFG0 | MACON3_TXCRCEN |
+				    MACON3_FRMLNEN);
+		enc28j60_regb_write(priv, MACON4, 1 << 6);	/* DEFER bit */
+		/* set inter-frame gap (non-back-to-back) */
+		enc28j60_regw_write(priv, MAIPGL, 0x0C12);
+		/* set inter-frame gap (back-to-back) */
+		enc28j60_regb_write(priv, MABBIPG, 0x12);
+	}
+	/*
+	 * MACLCON1 (default)
+	 * MACLCON2 (default)
+	 * Set the maximum packet size which the controller will accept
+	 */
+	enc28j60_regw_write(priv, MAMXFLL, MAX_FRAMELEN);
+
+	/* Configure LEDs */
+	if (!enc28j60_phy_write(priv, PHLCON, ENC28J60_LAMPS_MODE))
+		return 0;
+
+	if (priv->full_duplex) {
+		if (!enc28j60_phy_write(priv, PHCON1, PHCON1_PDPXMD))
+			return 0;
+		if (!enc28j60_phy_write(priv, PHCON2, 0x00))
+			return 0;
+	} else {
+		if (!enc28j60_phy_write(priv, PHCON1, 0x00))
+			return 0;
+		if (!enc28j60_phy_write(priv, PHCON2, PHCON2_HDLDIS))
+			return 0;
+	}
+
+	enc28j60_dump_regs(priv, "Hw initialized.");
+
+	return 1;
+}
+
+static void enc28j60_hw_enable(struct enc28j60_net *priv)
+{
+	dev_dbg(&priv->edev.dev, "%s()\n", __func__);
+
+	/* enable receive logic */
+	enc28j60_reg_bfset(priv, ECON1, ECON1_RXEN);
+	priv->hw_enable = true;
+}
+
+static void enc28j60_hw_disable(struct enc28j60_net *priv)
+{
+	/* disable interrutps and packet reception */
+	enc28j60_regb_write(priv, EIE, 0x00);
+	enc28j60_reg_bfclr(priv, ECON1, ECON1_RXEN);
+	priv->hw_enable = false;
+}
+
+/*
+ * Receive Status vector
+ */
+static inline void enc28j60_dump_rsv(struct enc28j60_net *priv, const char *msg,
+			      u16 pk_ptr, int len, u16 sts)
+{
+	struct device_d *dev = &priv->edev.dev;
+
+	dev_dbg(dev, "%s - NextPk: 0x%04x - RSV:\n",
+		msg, pk_ptr);
+	dev_dbg(dev, "ByteCount: %d, DribbleNibble: %d\n", len,
+		 RSV_GETBIT(sts, RSV_DRIBBLENIBBLE));
+	dev_dbg(dev, "RxOK: %d, CRCErr:%d, LenChkErr: %d,"
+		 " LenOutOfRange: %d\n", RSV_GETBIT(sts, RSV_RXOK),
+		 RSV_GETBIT(sts, RSV_CRCERROR),
+		 RSV_GETBIT(sts, RSV_LENCHECKERR),
+		 RSV_GETBIT(sts, RSV_LENOUTOFRANGE));
+	dev_dbg(dev, "Multicast: %d, Broadcast: %d, "
+		 "LongDropEvent: %d, CarrierEvent: %d\n",
+		 RSV_GETBIT(sts, RSV_RXMULTICAST),
+		 RSV_GETBIT(sts, RSV_RXBROADCAST),
+		 RSV_GETBIT(sts, RSV_RXLONGEVDROPEV),
+		 RSV_GETBIT(sts, RSV_CARRIEREV));
+	dev_dbg(dev, "ControlFrame: %d, PauseFrame: %d,"
+		 " UnknownOp: %d, VLanTagFrame: %d\n",
+		 RSV_GETBIT(sts, RSV_RXCONTROLFRAME),
+		 RSV_GETBIT(sts, RSV_RXPAUSEFRAME),
+		 RSV_GETBIT(sts, RSV_RXUNKNOWNOPCODE),
+		 RSV_GETBIT(sts, RSV_RXTYPEVLAN));
+}
+
+/*
+ * Hardware transmit function.
+ * Fill the buffer memory and send the contents of the transmit buffer
+ * onto the network
+ */
+static int enc28j60_eth_send(struct eth_device *edev, void *packet,
+				int packet_length)
+{
+	struct enc28j60_net *priv = edev->priv;
+
+	dev_dbg(&edev->dev, "Tx Packet Len:%d\n", packet_length);
+
+	enc28j60_packet_write(priv, packet_length, packet);
+
+	/* readback and verify written data */
+	if (IS_ENABLED(CONFIG_ENC28J60_WRITEVERIFY)) {
+		int test_len, k;
+		u8 test_buf[64]; /* limit the test to the first 64 bytes */
+		int okflag;
+
+		test_len = packet_length;
+		if (test_len > sizeof(test_buf))
+			test_len = sizeof(test_buf);
+
+		/* + 1 to skip control byte */
+		enc28j60_mem_read(priv, TXSTART_INIT + 1, test_len, test_buf);
+		okflag = 1;
+		for (k = 0; k < test_len; k++) {
+			if (((u8 *)packet)[k] != test_buf[k]) {
+				dev_dbg(&edev->dev,
+					 "Error, %d location differ: "
+					 "0x%02x-0x%02x\n", k,
+					 ((u8 *)packet)[k], test_buf[k]);
+				okflag = 0;
+			}
+		}
+		if (!okflag)
+			dev_dbg(&edev->dev, "Tx write buffer verify ERROR!\n");
+	}
+
+	/* set TX request flag */
+	enc28j60_reg_bfset(priv, ECON1, ECON1_TXRTS);
+
+	return 0;
+}
+
+/*
+ * Hardware receive function.
+ * Read the buffer memory, update the FIFO pointer to free the buffer,
+ * check the status vector and decrement the packet counter.
+ */
+static void enc28j60_hw_rx(struct eth_device *edev)
+{
+	struct enc28j60_net *priv = edev->priv;
+	u16 erxrdpt, next_packet, rxstat;
+	u8 rsv[RSV_SIZE];
+	int len;
+
+	dev_dbg(&edev->dev, "RX pk_addr:0x%04x\n", priv->next_pk_ptr);
+
+	if (unlikely(priv->next_pk_ptr > RXEND_INIT)) {
+		dev_err(&edev->dev, "%s() Invalid packet address!! 0x%04x\n",
+			__func__, priv->next_pk_ptr);
+
+		/* packet address corrupted: reset RX logic */
+		enc28j60_reg_bfclr(priv, ECON1, ECON1_RXEN);
+		enc28j60_reg_bfset(priv, ECON1, ECON1_RXRST);
+		enc28j60_reg_bfclr(priv, ECON1, ECON1_RXRST);
+		enc28j60_rxfifo_init(priv, RXSTART_INIT, RXEND_INIT);
+		enc28j60_reg_bfclr(priv, EIR, EIR_RXERIF);
+		enc28j60_reg_bfset(priv, ECON1, ECON1_RXEN);
+
+		return;
+	}
+
+	/* Read next packet pointer and rx status vector */
+	enc28j60_mem_read(priv, priv->next_pk_ptr, sizeof(rsv), rsv);
+
+	next_packet = rsv[1];
+	next_packet <<= 8;
+	next_packet |= rsv[0];
+
+	len = rsv[3];
+	len <<= 8;
+	len |= rsv[2];
+
+	rxstat = rsv[5];
+	rxstat <<= 8;
+	rxstat |= rsv[4];
+
+	enc28j60_dump_rsv(priv, __func__, next_packet, len, rxstat);
+
+	if (!RSV_GETBIT(rxstat, RSV_RXOK) || len > MAX_FRAMELEN) {
+		dev_err(&edev->dev, "Rx Error (%04x)\n", rxstat);
+	} else {
+		/* copy the packet from the receive buffer */
+		enc28j60_mem_read(priv,
+			rx_packet_start(priv->next_pk_ptr),
+			len, NetRxPackets[0]);
+
+		net_receive(edev, NetRxPackets[0], len);
+	}
+
+	/*
+	 * Move the RX read pointer to the start of the next
+	 * received packet.
+	 * This frees the memory we just read out
+	 */
+	erxrdpt = erxrdpt_workaround(next_packet, RXSTART_INIT, RXEND_INIT);
+	dev_dbg(&edev->dev, ": %s() ERXRDPT:0x%04x\n", __func__, erxrdpt);
+
+	enc28j60_regw_write(priv, ERXRDPTL, erxrdpt);
+
+	if (IS_ENABLED(CONFIG_ENC28J60_WRITEVERIFY)) {
+		u16 reg;
+		reg = enc28j60_regw_read(priv, ERXRDPTL);
+		if (reg != erxrdpt)
+			dev_dbg(&edev->dev, "%s() ERXRDPT verify "
+				"error (0x%04x - 0x%04x)\n", __func__,
+				reg, erxrdpt);
+	}
+
+	priv->next_pk_ptr = next_packet;
+
+	/* we are done with this packet, decrement the packet counter */
+	enc28j60_reg_bfset(priv, ECON2, ECON2_PKTDEC);
+}
+
+/*
+ * Access the PHY to determine link status
+ */
+static void enc28j60_check_link_status(struct eth_device *edev)
+{
+	struct enc28j60_net *priv = edev->priv;
+	u16 reg;
+	int duplex;
+
+	reg = enc28j60_phy_read(priv, PHSTAT2);
+	dev_dbg(&edev->dev, "%s() PHSTAT1: %04x, PHSTAT2: %04x\n", __func__,
+			enc28j60_phy_read(priv, PHSTAT1), reg);
+	duplex = reg & PHSTAT2_DPXSTAT;
+
+	if (reg & PHSTAT2_LSTAT) {
+		dev_dbg(&edev->dev, "link up - %s\n",
+			duplex ? "Full duplex" : "Half duplex");
+	} else {
+		dev_dbg(&edev->dev, "link down\n");
+	}
+}
+
+static int enc28j60_eth_rx(struct eth_device *edev)
+{
+	struct enc28j60_net *priv = edev->priv;
+	int pk_counter;
+
+	pk_counter = enc28j60_regb_read(priv, EPKTCNT);
+	if (pk_counter)
+		dev_dbg(&edev->dev, "intRX, pk_cnt: %d\n", pk_counter);
+
+	if (pk_counter > priv->max_pk_counter) {
+		priv->max_pk_counter = pk_counter;
+		if (priv->max_pk_counter > 1)
+			dev_dbg(&edev->dev,
+				"RX max_pk_cnt: %d\n", priv->max_pk_counter);
+	}
+
+	while (pk_counter-- > 0)
+		enc28j60_hw_rx(edev);
+
+	return 0;
+}
+
+static int enc28j60_init_dev(struct eth_device *edev)
+{
+	/* empty */
+
+	return 0;
+}
+
+/*
+ * Open/initialize the board. This is called (in the current kernel)
+ * sometime after booting when the 'ifconfig' program is run.
+ *
+ * This routine should set everything up anew at each open, even
+ * registers that "should" only need to be set once at boot, so that
+ * there is non-reboot way to recover if something goes wrong.
+ */
+static int enc28j60_eth_open(struct eth_device *edev)
+{
+	struct enc28j60_net *priv = edev->priv;
+	int ret;
+
+	dev_dbg(&edev->dev, "%s() enter\n", __func__);
+
+	/* Reset the hardware here (and take it out of low power mode) */
+	enc28j60_lowpower(priv, false);
+	enc28j60_hw_disable(priv);
+	if (!enc28j60_hw_init(priv)) {
+		dev_err(&edev->dev, "hw_init() failed\n");
+		return -EINVAL;
+	}
+
+	/* Update the MAC address after reset */
+	enc28j60_set_ethaddr(edev, priv->hwaddr);
+
+	enc28j60_hw_enable(priv);
+
+	/* Wait for link up after hardware reset */
+	mdelay(2000);
+
+	ret = phy_device_connect(edev, &priv->miibus, 0,
+				&enc28j60_check_link_status, 0,
+				PHY_INTERFACE_MODE_MII);
+
+	return ret;
+}
+
+static void enc28j60_eth_halt(struct eth_device *edev)
+{
+	struct enc28j60_net *priv = edev->priv;
+
+	dev_dbg(&edev->dev, "%s() enter\n", __func__);
+
+	enc28j60_hw_disable(priv);
+	enc28j60_lowpower(priv, true);
+}
+
+static int enc28j60_probe(struct device_d *dev)
+{
+	struct eth_device *edev;
+	struct enc28j60_net *priv;
+	int ret = 0;
+
+	priv = xzalloc(sizeof(*priv));
+
+	priv->spi = (struct spi_device *)dev->type_data;
+
+	edev = &priv->edev;
+	edev->priv = priv;
+	edev->init = enc28j60_init_dev;
+	edev->open = enc28j60_eth_open;
+	edev->send = enc28j60_eth_send;
+	edev->recv = enc28j60_eth_rx;
+	edev->get_ethaddr = enc28j60_get_ethaddr;
+	edev->set_ethaddr = enc28j60_set_ethaddr;
+	edev->halt = enc28j60_eth_halt;
+	edev->parent = dev;
+
+	/*
+	 * Here is a quote from ENC28J60 Data Sheet:
+	 *
+	 * The ENC28J60 does not support automatic duplex
+	 * negotiation. If it is connected to an automatic duplex
+	 * negotiation enabled network switch or Ethernet controller,
+	 * the ENC28J60 will be detected as a half-duplex device.
+	 *
+	 * So most people prefer to set up half-duplex mode.
+	 */
+	priv->full_duplex = 0;
+
+	ret = eth_register(edev);
+	if (ret)
+		goto eth_error_register;
+
+	if (!enc28j60_hw_init(priv)) {
+		dev_err(dev, DRV_NAME " chip not found\n");
+		ret = -EIO;
+		goto hw_error_register;
+	}
+
+	enc28j60_lowpower(priv, true);
+
+	priv->miibus.read = enc28j60_miibus_read;
+	priv->miibus.write = enc28j60_miibus_write;
+
+	priv->miibus.priv = priv;
+	priv->miibus.parent = dev;
+
+	ret = mdiobus_register(&priv->miibus);
+	if (ret)
+		goto mdio_error_register;
+
+	dev_info(dev, DRV_NAME " driver registered\n");
+
+	return 0;
+
+mdio_error_register:
+hw_error_register:
+	eth_unregister(edev);
+
+eth_error_register:
+	free(priv);
+
+	return ret;
+}
+
+static __maybe_unused struct of_device_id enc28j60_dt_ids[] = {
+	{
+		.compatible = "microchip,enc28j60",
+	}, {
+		/* sentinel */
+	}
+};
+
+static struct driver_d enc28j60_driver = {
+	.name = DRV_NAME,
+	.probe = enc28j60_probe,
+	.of_compatible = DRV_OF_COMPAT(enc28j60_dt_ids),
+};
+device_spi_driver(enc28j60_driver);