drivers/ethernet/eth_enc28j60.c - third_party/github/zephyrproject-rtos/zephyr - Git at Google

 /* ENC28J60 Stand-alone Ethernet Controller with SPI
  *
  * Copyright (c) 2016 Intel Corporation
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include <net/ip/net_driver_ethernet.h>
 #include <zephyr.h>
 #include <string.h>
 #include <errno.h>
 #include <gpio.h>
 #include <spi.h>
 #include <eth.h>

 #include "eth_enc28j60_priv.h"

 #define D10D24S 11
 #define MAX_BUFFER_LENGTH 100

 static int eth_net_tx(struct net_buf *buf);
 static void enc28j60_fiber_main(int arg1, int unused);

 static int eth_enc28j60_soft_reset(struct device *dev)
 {
 	struct eth_enc28j60_runtime *context = dev->driver_data;
 	uint8_t tx_buf[2] = {ENC28J60_SPI_SC, 0xFF};

 	return spi_write(context->spi, tx_buf, 2);
 }

 static void eth_enc28j60_set_bank(struct device *dev, uint16_t reg_addr)
 {
 	struct eth_enc28j60_runtime *context = dev->driver_data;
 	uint8_t tx_buf[2];

 	nano_fiber_sem_take(&context->spi_sem, TICKS_UNLIMITED);

 	tx_buf[0] = ENC28J60_SPI_RCR | ENC28J60_REG_ECON1;
 	tx_buf[1] = 0x0;

 	spi_transceive(context->spi, tx_buf, 2, tx_buf, 2);

 	tx_buf[0] = ENC28J60_SPI_WCR | ENC28J60_REG_ECON1;
 	tx_buf[1] = (tx_buf[1] & 0xFC) | ((reg_addr >> 8) & 0x0F);

 	spi_write(context->spi, tx_buf, 2);

 	nano_fiber_sem_give(&context->spi_sem);
 }

 static void eth_enc28j60_write_reg(struct device *dev, uint16_t reg_addr,
 				   uint8_t value)
 {
 	struct eth_enc28j60_runtime *context = dev->driver_data;
 	uint8_t tx_buf[2];

 	nano_fiber_sem_take(&context->spi_sem, TICKS_UNLIMITED);

 	tx_buf[0] = ENC28J60_SPI_WCR | (reg_addr & 0xFF);
 	tx_buf[1] = value;

 	spi_write(context->spi, tx_buf, 2);

 	nano_fiber_sem_give(&context->spi_sem);
 }

 static void eth_enc28j60_read_reg(struct device *dev, uint16_t reg_addr,
 				  uint8_t *value)
 {
 	struct eth_enc28j60_runtime *context = dev->driver_data;
 	uint8_t tx_size = 2;
 	uint8_t tx_buf[3];

 	nano_fiber_sem_take(&context->spi_sem, TICKS_UNLIMITED);

 	if (reg_addr & 0xF000) {
 		tx_size = 3;
 	}

 	tx_buf[0] = ENC28J60_SPI_RCR | (reg_addr & 0xFF);
 	tx_buf[1] = 0x0;

 	spi_transceive(context->spi, tx_buf, tx_size, tx_buf, tx_size);

 	*value = tx_buf[tx_size - 1];

 	nano_fiber_sem_give(&context->spi_sem);
 }

 static void eth_enc28j60_set_eth_reg(struct device *dev, uint16_t reg_addr,
 				     uint8_t value)
 {
 	struct eth_enc28j60_runtime *context = dev->driver_data;
 	uint8_t tx_buf[2];

 	nano_fiber_sem_take(&context->spi_sem, TICKS_UNLIMITED);

 	tx_buf[0] = ENC28J60_SPI_BFS | (reg_addr & 0xFF);
 	tx_buf[1] = value;

 	spi_write(context->spi, tx_buf, 2);

 	nano_fiber_sem_give(&context->spi_sem);
 }


 static void eth_enc28j60_clear_eth_reg(struct device *dev, uint16_t reg_addr,
 				       uint8_t value)
 {
 	struct eth_enc28j60_runtime *context = dev->driver_data;
 	uint8_t tx_buf[2];

 	nano_fiber_sem_take(&context->spi_sem, TICKS_UNLIMITED);

 	tx_buf[0] = ENC28J60_SPI_BFC | (reg_addr & 0xFF);
 	tx_buf[1] = value;

 	spi_write(context->spi, tx_buf, 2);

 	nano_fiber_sem_give(&context->spi_sem);
 }

 static void eth_enc28j60_write_mem(struct device *dev, uint8_t *data_buffer,
 				   uint8_t buf_len)
 {
 	struct eth_enc28j60_runtime *context = dev->driver_data;
 	uint8_t tx_buf[MAX_BUFFER_LENGTH + 1];
 	uint8_t *index_buf;
 	uint16_t num_segments;
 	uint16_t num_remanents;

 	index_buf = data_buffer;
 	num_segments = buf_len / MAX_BUFFER_LENGTH;
 	num_remanents = buf_len - MAX_BUFFER_LENGTH * num_segments;

 	nano_fiber_sem_take(&context->spi_sem, TICKS_UNLIMITED);

 	tx_buf[0] = ENC28J60_SPI_WBM;

 	for (int i = 0; i < num_segments;
 	     ++i, index_buf += i * MAX_BUFFER_LENGTH) {

 		memcpy(tx_buf + 1, index_buf, MAX_BUFFER_LENGTH);

 		spi_write(context->spi, tx_buf, MAX_BUFFER_LENGTH + 1);

 	}
 	memcpy(tx_buf + 1, index_buf, num_remanents);

 	spi_write(context->spi, tx_buf, num_remanents + 1);

 	nano_fiber_sem_give(&context->spi_sem);
 }

 static void eth_enc28j60_read_mem(struct device *dev, uint8_t *data_buffer,
 				  uint8_t buf_len)
 {
 	struct eth_enc28j60_runtime *context = dev->driver_data;
 	uint8_t *index_buf;
 	uint8_t tx_buf[MAX_BUFFER_LENGTH + 1];
 	uint16_t num_segments;
 	uint16_t num_remanents;

 	index_buf = data_buffer;
 	num_segments = buf_len / MAX_BUFFER_LENGTH;
 	num_remanents = buf_len - MAX_BUFFER_LENGTH * num_segments;

 	nano_fiber_sem_take(&context->spi_sem, TICKS_UNLIMITED);

 	tx_buf[0] = ENC28J60_SPI_RBM;

 	for (int i = 0; i < num_segments;
 	     ++i, index_buf += i * MAX_BUFFER_LENGTH) {

 		spi_transceive(context->spi, tx_buf, MAX_BUFFER_LENGTH + 1,
 			       tx_buf, MAX_BUFFER_LENGTH + 1);

 		memcpy(index_buf, tx_buf + 1, MAX_BUFFER_LENGTH);
 	}

 	spi_transceive(context->spi, tx_buf, num_remanents + 1,
 		       tx_buf, num_remanents + 1);

 	memcpy(index_buf, tx_buf + 1, num_remanents);

 	nano_fiber_sem_give(&context->spi_sem);
 }

 static void eth_enc28j60_write_phy(struct device *dev, uint16_t reg_addr,
 				   int16_t data)
 {
 	uint8_t data_mistat;

 	eth_enc28j60_set_bank(dev, ENC28J60_REG_MIREGADR);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_MIREGADR, reg_addr);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_MIWRL, data & 0xFF);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_MIWRH, data >> 8);
 	eth_enc28j60_set_bank(dev, ENC28J60_REG_MISTAT);

 	do {
 		/* wait 10.24 useconds */
 		sys_thread_busy_wait(D10D24S);
 		eth_enc28j60_read_reg(dev, ENC28J60_REG_MISTAT,
 				      &data_mistat);
 	} while ((data_mistat & ENC28J60_BIT_MISTAT_BUSY));
 }

 static void eth_enc28j60_gpio_callback(struct device *dev,
 				       struct gpio_callback *cb,
 				       uint32_t pins)
 {
 	struct eth_enc28j60_runtime *context =
 		CONTAINER_OF(cb, struct eth_enc28j60_runtime, gpio_cb);

 	nano_fiber_sem_give(&context->int_sem);
 }

 static void eth_enc28j60_init_buffers(struct device *dev)
 {
 	uint8_t data_estat;

 	/* Reception buffers initialization */
 	eth_enc28j60_set_bank(dev, ENC28J60_REG_ERXSTL);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXSTL,
 			       ENC28J60_RXSTART & 0xFF);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXSTH,
 			       ENC28J60_RXSTART >> 8);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXRDPTL,
 			       ENC28J60_RXSTART & 0xFF);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXRDPTH,
 			       ENC28J60_RXSTART >> 8);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXNDL,
 			       ENC28J60_RXEND & 0xFF);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXNDH,
 			       ENC28J60_RXEND >> 8);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXSTL,
 			       ENC28J60_TXSTART & 0xFF);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXSTH,
 			       ENC28J60_TXSTART >> 8);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXNDL,
 			       ENC28J60_TXEND & 0xFF);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXNDH,
 			       ENC28J60_TXEND >> 8);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERDPTL,
 			       ENC28J60_RXSTART & 0xFF);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERDPTH,
 			       ENC28J60_RXSTART >> 8);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_EWRPTL,
 			       ENC28J60_TXSTART & 0xFF);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_EWRPTH,
 			       ENC28J60_TXSTART >> 8);

 	eth_enc28j60_set_bank(dev, ENC28J60_REG_ERXFCON);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXFCON,
 			       ENC28J60_RECEIVE_FILTERS);

 	/* Waiting for OST */
 	do {
 		/* wait 10.24 useconds */
 		sys_thread_busy_wait(D10D24S);
 		eth_enc28j60_read_reg(dev, ENC28J60_REG_ESTAT, &data_estat);
 	} while (!(data_estat & ENC28J60_BIT_ESTAT_CLKRDY));
 }

 static void eth_enc28j60_init_mac(struct device *dev)
 {
 	const struct eth_enc28j60_config *config = dev->config->config_info;
 	uint8_t data_macon;
 	uint8_t mac_address[6];

 	eth_enc28j60_set_bank(dev, ENC28J60_REG_MACON1);

 	/* Set MARXEN to enable MAC to receive frames */
 	eth_enc28j60_read_reg(dev, ENC28J60_REG_MACON1, &data_macon);
 	data_macon |= ENC28J60_BIT_MACON1_MARXEN | ENC28J60_BIT_MACON1_RXPAUS
 		      | ENC28J60_BIT_MACON1_TXPAUS;
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_MACON1, data_macon);

 	data_macon = ENC28J60_MAC_CONFIG;

 	if (config->full_duplex) {
 		data_macon |= ENC28J60_BIT_MACON3_FULDPX;
 	}

 	eth_enc28j60_write_reg(dev, ENC28J60_REG_MACON3, data_macon);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_MAIPGL, ENC28J60_MAC_NBBIPGL);

 	if (config->full_duplex) {
 		eth_enc28j60_write_reg(dev, ENC28J60_REG_MAIPGH,
 				       ENC28J60_MAC_NBBIPGH);
 		eth_enc28j60_write_reg(dev, ENC28J60_REG_MABBIPG,
 				       ENC28J60_MAC_BBIPG_FD);
 	} else {
 		eth_enc28j60_write_reg(dev, ENC28J60_REG_MABBIPG,
 				       ENC28J60_MAC_BBIPG_HD);
 		eth_enc28j60_write_reg(dev, ENC28J60_REG_MACON4, 1 << 6);
 	}

 	/* Configure MAC address */
 	mac_address[0] = MICROCHIP_OUI_B0;
 	mac_address[1] = MICROCHIP_OUI_B1;
 	mac_address[2] = MICROCHIP_OUI_B2;
 	mac_address[3] = CONFIG_ETH_ENC28J60_0_MAC3;
 	mac_address[4] = CONFIG_ETH_ENC28J60_0_MAC4;
 	mac_address[5] = CONFIG_ETH_ENC28J60_0_MAC5;
 	net_set_mac(mac_address, sizeof(mac_address));

 	eth_enc28j60_set_bank(dev, ENC28J60_REG_MAADR0);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_MAADR0,
 			       CONFIG_ETH_ENC28J60_0_MAC5);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_MAADR1,
 			       CONFIG_ETH_ENC28J60_0_MAC4);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_MAADR2,
 			       CONFIG_ETH_ENC28J60_0_MAC3);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_MAADR3, MICROCHIP_OUI_B2);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_MAADR4, MICROCHIP_OUI_B1);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_MAADR5, MICROCHIP_OUI_B0);
 }

 static void eth_enc28j60_init_phy(struct device *dev)
 {
 	const struct eth_enc28j60_config *config = dev->config->config_info;

 	if (config->full_duplex) {
 		eth_enc28j60_write_phy(dev, ENC28J60_PHY_PHCON1,
 				       ENC28J60_BIT_PHCON1_PDPXMD);
 		eth_enc28j60_write_phy(dev, ENC28J60_PHY_PHCON2, 0x0);
 	} else {
 		eth_enc28j60_write_phy(dev, ENC28J60_PHY_PHCON1, 0x0);
 		eth_enc28j60_write_phy(dev, ENC28J60_PHY_PHCON2,
 				       ENC28J60_BIT_PHCON2_HDLDIS);
 	}
 }

 static int eth_enc28j60_init(struct device *dev)
 {
 	const struct eth_enc28j60_config *config = dev->config->config_info;
 	struct eth_enc28j60_runtime *context = dev->driver_data;
 	struct spi_config spi_cfg;

 	nano_sem_init(&context->spi_sem);
 	nano_fiber_sem_give(&context->spi_sem);

 	context->gpio = device_get_binding((char *)config->gpio_port);
 	if (!context->gpio) {
 		return -EINVAL;
 	}

 	context->spi = device_get_binding((char *)config->spi_port);
 	if (!context->spi) {
 		return -EINVAL;
 	}

 	/* Initialize GPIO */
 	if (gpio_pin_configure(context->gpio, config->gpio_pin,
 			       (GPIO_DIR_IN | GPIO_INT | GPIO_INT_EDGE
 			       | GPIO_INT_ACTIVE_LOW | GPIO_INT_DEBOUNCE))) {
 		return -EINVAL;
 	}

 	gpio_init_callback(&(context->gpio_cb), eth_enc28j60_gpio_callback,
 			   BIT(config->gpio_pin));

 	if (gpio_add_callback(context->gpio, &(context->gpio_cb))) {
 		return -EINVAL;
 	}

 	if (gpio_pin_enable_callback(context->gpio, config->gpio_pin)) {
 		return -EINVAL;
 	}

 	/* Initialize SPI:
 	 * Mode: 0/0; Size: 8 bits; MSB
 	 */
 	spi_cfg.config = 8 << 4;
 	spi_cfg.max_sys_freq = config->spi_freq;

 	if (spi_configure(context->spi, &spi_cfg) < 0) {
 		return -EIO;
 	}

 	if (spi_slave_select(context->spi, config->spi_slave) < 0) {
 		return -EIO;
 	}

 	if (eth_enc28j60_soft_reset(dev)) {
 		return -EIO;
 	}

 	/* Errata B7/2 */
 	sys_thread_busy_wait(D10D24S);

 	eth_enc28j60_init_buffers(dev);
 	eth_enc28j60_init_mac(dev);
 	eth_enc28j60_init_phy(dev);

 	/* Enable interruptions */
 	eth_enc28j60_set_eth_reg(dev, ENC28J60_REG_EIE, ENC28J60_BIT_EIE_INTIE);
 	eth_enc28j60_set_eth_reg(dev, ENC28J60_REG_EIE, ENC28J60_BIT_EIE_PKTIE);

 	/* Enable Reception */
 	eth_enc28j60_set_eth_reg(dev, ENC28J60_REG_ECON1,
 				 ENC28J60_BIT_ECON1_RXEN);

 	/* Register tx callback into IP stack */
 	net_driver_ethernet_register_tx(eth_net_tx);

 	/* Initialize semaphores */
 	nano_sem_init(&context->tx_sem);
 	nano_sem_init(&context->int_sem);
 	nano_sem_give(&context->tx_sem);

 	/* Start interruption-poll fiber */
 	fiber_start(context->fiber_stack, ENC28J60_FIBER_STACK_SIZE,
 		    enc28j60_fiber_main, (int)dev, 0,
 		    ENC28J60_FIBER_PRIORITY, 0);

 	return 0;
 }

 static int eth_enc28j60_tx(struct device *dev, uint8_t *buf, uint16_t len)
 {
 	struct eth_enc28j60_runtime *context = dev->driver_data;
 	uint16_t tx_bufaddr = ENC28J60_TXSTART;
 	uint8_t per_packet_control;
 	uint16_t tx_bufaddr_end;
 	uint8_t tx_end;

 	nano_fiber_sem_take(&context->tx_sem, TICKS_UNLIMITED);

 	/* Latest errata sheet: DS80349C
 	* always reset transmit logic (Errata Issue 12)
 	* the Microchip TCP/IP stack implementation used to first check
 	* whether TXERIF is set and only then reset the transmit logic
 	* but this has been changed in later versions; possibly they
 	* have a reason for this; they don't mention this in the errata
 	* sheet
 	*/
 	eth_enc28j60_set_eth_reg(dev, ENC28J60_REG_ECON1,
 				 ENC28J60_BIT_ECON1_TXRST);
 	eth_enc28j60_clear_eth_reg(dev, ENC28J60_REG_ECON1,
 				   ENC28J60_BIT_ECON1_TXRST);

 	/* Write the buffer content into the transmission buffer */
 	eth_enc28j60_set_bank(dev, ENC28J60_REG_ETXSTL);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_EWRPTL, tx_bufaddr & 0xFF);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_EWRPTH, tx_bufaddr >> 8);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXSTL, tx_bufaddr & 0xFF);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXSTH, tx_bufaddr >> 8);

 	/* Write the data into the buffer */
 	per_packet_control = ENC28J60_PPCTL_BYTE;
 	eth_enc28j60_write_mem(dev, &per_packet_control, 1);
 	eth_enc28j60_write_mem(dev, buf, len);

 	tx_bufaddr_end = tx_bufaddr + len;
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXNDL,
 			       tx_bufaddr_end & 0xFF);
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXNDH, tx_bufaddr_end >> 8);

 	/* Signal ENC28J60 to send the buffer */
 	eth_enc28j60_set_eth_reg(dev, ENC28J60_REG_ECON1,
 				 ENC28J60_BIT_ECON1_TXRTS);

 	do {
 		/* wait 10.24 useconds */
 		sys_thread_busy_wait(D10D24S);
 		eth_enc28j60_read_reg(dev, ENC28J60_REG_EIR, &tx_end);
 		tx_end &= ENC28J60_BIT_EIR_TXIF;
 	} while (!tx_end);

 	eth_enc28j60_read_reg(dev, ENC28J60_REG_EIR, &tx_end);

 	nano_sem_give(&context->tx_sem);

 	if (tx_end & ENC28J60_BIT_ESTAT_TXABRT)	{
 		return -1;
 	}

 	return 0;
 }

 static int eth_enc28j60_rx(struct device *dev)
 {
 	struct eth_enc28j60_runtime *context = dev->driver_data;
 	uint8_t econ1_bkup;
 	uint8_t counter;

 	/* Errata 6. The Receive Packet Pending Interrupt Flag (EIR.PKTIF)
 	 * does not reliably/accurately report the status of pending packet.
 	 * Use EPKTCNT register instead.
 	*/

 	/* Backup ECON1 register in case the rx interrupted a tx process */
 	eth_enc28j60_read_reg(dev, ENC28J60_REG_ECON1, &econ1_bkup);

 	do {
 		uint8_t *reception_buf = NULL;
 		uint16_t frm_len = 0;
 		uint16_t next_packet;
 		struct net_buf *buf;
 		uint8_t np[2];

 		/* Read address for next packet */
 		eth_enc28j60_read_mem(dev, np, 2);
 		next_packet = np[0] | (uint16_t)np[1] << 8;

 		/* Errata 14. Even values in ERXRDPT
 		 * may corrupt receive buffer.
 		 */
 		if (next_packet == 0) {
 			next_packet = ENC28J60_RXEND;
 		} else if (!(next_packet & 0x01)) {
 			next_packet--;
 		}

 		/* Read reception status vector */
 		eth_enc28j60_read_mem(dev, context->rx_rsv, 4);

 		/* Get the frame length from the rx status vector */
 		frm_len = (context->rx_rsv[1] << 8) | context->rx_rsv[0];

 		if (frm_len > (UIP_BUFSIZE)) {
 			goto done;
 		}
 		/* Get the frame from the buffer */
 		buf = ip_buf_get_reserve_rx(0);

 		reception_buf = net_buf_add(buf, frm_len);

 		if (reception_buf == NULL) {
 			frm_len = 0;
 			goto done;
 		}

 		eth_enc28j60_read_mem(dev, reception_buf, frm_len);
 		uip_len(buf) = frm_len;

 		/* Register the buffer frame with the IP stack */
 		net_driver_ethernet_recv(buf);
 done:
 		/* Free buffer memory and decrement rx counter */
 		eth_enc28j60_set_bank(dev, ENC28J60_REG_ERXRDPTL);
 		eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXRDPTL,
 				       next_packet & 0xFF);
 		eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXRDPTH,
 				       next_packet >> 8);
 		eth_enc28j60_set_eth_reg(dev, ENC28J60_REG_ECON2,
 					 ENC28J60_BIT_ECON2_PKTDEC);

 		/* Call receive callback */
 		if (context->receive_callback) {
 			context->receive_callback(reception_buf, frm_len);
 		}

 		/* Check if there are frames to clean from the buffer */
 		eth_enc28j60_read_reg(dev, ENC28J60_REG_EPKTCNT, &counter);
 	} while (counter);

 	/* Recover ECON1 register */
 	eth_enc28j60_write_reg(dev, ENC28J60_REG_ECON1, econ1_bkup);

 	return 0;
 }

 void eth_enc28j60_reg_cb(struct device *dev,
 			 void (*cb)(uint8_t *buffer, uint16_t len))
 {
 	struct eth_enc28j60_runtime *context = dev->driver_data;

 	context->receive_callback = cb;
 }

 static void enc28j60_fiber_main(int arg1, int unused)
 {
 	struct device *dev = (struct device *)arg1;
 	struct eth_enc28j60_runtime *context;
 	uint8_t int_stat;

 	ARG_UNUSED(unused);

 	context = dev->driver_data;

 	while (1) {
 		nano_fiber_sem_take(&context->int_sem, TICKS_UNLIMITED);
 		eth_enc28j60_read_reg(dev, ENC28J60_REG_EIR, &int_stat);

 		if (int_stat & ENC28J60_BIT_EIR_PKTIF) {
 			eth_enc28j60_rx(dev);
 			/* Clear rx interruption flag */
 			eth_enc28j60_clear_eth_reg(dev, ENC28J60_REG_EIR,
 						   ENC28J60_BIT_EIR_PKTIF
 						   | ENC28J60_BIT_EIR_RXERIF);
 		}
 	}
 }

 static struct eth_driver_api api_funcs = {
 	.send = eth_enc28j60_tx,
 	.register_callback = eth_enc28j60_reg_cb,
 };

 #ifdef CONFIG_ETH_ENC28J60_0
 static struct eth_enc28j60_runtime eth_enc28j60_0_runtime = {
 	.receive_callback = NULL,
 };

 static const struct eth_enc28j60_config eth_enc28j60_0_config = {
 	.gpio_port = CONFIG_ETH_ENC28J60_0_GPIO_PORT_NAME,
 	.gpio_pin = CONFIG_ETH_ENC28J60_0_GPIO_PIN,
 	.spi_port = CONFIG_ETH_ENC28J60_0_SPI_PORT_NAME,
 	.spi_freq  = CONFIG_ETH_ENC28J60_0_SPI_BUS_FREQ,
 	.spi_slave = CONFIG_ETH_ENC28J60_0_SLAVE,
 	.full_duplex = CONFIG_ETH_EN28J60_0_FULL_DUPLEX,
 };

 DEVICE_AND_API_INIT(eth_enc28j60_0, CONFIG_ETH_ENC28J60_0_NAME,
 		    &eth_enc28j60_init, &eth_enc28j60_0_runtime,
 		    &eth_enc28j60_0_config, SECONDARY,
 		    CONFIG_ETH_ENC28J60_0_INIT_PRIORITY, &api_funcs);

 static int eth_net_tx(struct net_buf *buf)
 {
 	return eth_enc28j60_tx(DEVICE_GET(eth_enc28j60_0),
 			       uip_buf(buf), uip_len(buf));
 }

 #endif /* CONFIG_ETH_ENC28J60_0 */
	/* ENC28J60 Stand-alone Ethernet Controller with SPI
	*
	* Copyright (c) 2016 Intel Corporation
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include <net/ip/net_driver_ethernet.h>
	#include <zephyr.h>
	#include <string.h>
	#include <errno.h>
	#include <gpio.h>
	#include <spi.h>
	#include <eth.h>

	#include "eth_enc28j60_priv.h"

	#define D10D24S 11
	#define MAX_BUFFER_LENGTH 100

	static int eth_net_tx(struct net_buf *buf);
	static void enc28j60_fiber_main(int arg1, int unused);

	static int eth_enc28j60_soft_reset(struct device *dev)
	{
	struct eth_enc28j60_runtime *context = dev->driver_data;
	uint8_t tx_buf[2] = {ENC28J60_SPI_SC, 0xFF};

	return spi_write(context->spi, tx_buf, 2);
	}

	static void eth_enc28j60_set_bank(struct device *dev, uint16_t reg_addr)
	{
	struct eth_enc28j60_runtime *context = dev->driver_data;
	uint8_t tx_buf[2];

	nano_fiber_sem_take(&context->spi_sem, TICKS_UNLIMITED);

	tx_buf[0] = ENC28J60_SPI_RCR \| ENC28J60_REG_ECON1;
	tx_buf[1] = 0x0;

	spi_transceive(context->spi, tx_buf, 2, tx_buf, 2);

	tx_buf[0] = ENC28J60_SPI_WCR \| ENC28J60_REG_ECON1;
	tx_buf[1] = (tx_buf[1] & 0xFC) \| ((reg_addr >> 8) & 0x0F);

	spi_write(context->spi, tx_buf, 2);

	nano_fiber_sem_give(&context->spi_sem);
	}

	static void eth_enc28j60_write_reg(struct device *dev, uint16_t reg_addr,
	uint8_t value)
	{
	struct eth_enc28j60_runtime *context = dev->driver_data;
	uint8_t tx_buf[2];

	nano_fiber_sem_take(&context->spi_sem, TICKS_UNLIMITED);

	tx_buf[0] = ENC28J60_SPI_WCR \| (reg_addr & 0xFF);
	tx_buf[1] = value;

	spi_write(context->spi, tx_buf, 2);

	nano_fiber_sem_give(&context->spi_sem);
	}

	static void eth_enc28j60_read_reg(struct device *dev, uint16_t reg_addr,
	uint8_t *value)
	{
	struct eth_enc28j60_runtime *context = dev->driver_data;
	uint8_t tx_size = 2;
	uint8_t tx_buf[3];

	nano_fiber_sem_take(&context->spi_sem, TICKS_UNLIMITED);

	if (reg_addr & 0xF000) {
	tx_size = 3;
	}

	tx_buf[0] = ENC28J60_SPI_RCR \| (reg_addr & 0xFF);
	tx_buf[1] = 0x0;

	spi_transceive(context->spi, tx_buf, tx_size, tx_buf, tx_size);

	*value = tx_buf[tx_size - 1];

	nano_fiber_sem_give(&context->spi_sem);
	}

	static void eth_enc28j60_set_eth_reg(struct device *dev, uint16_t reg_addr,
	uint8_t value)
	{
	struct eth_enc28j60_runtime *context = dev->driver_data;
	uint8_t tx_buf[2];

	nano_fiber_sem_take(&context->spi_sem, TICKS_UNLIMITED);

	tx_buf[0] = ENC28J60_SPI_BFS \| (reg_addr & 0xFF);
	tx_buf[1] = value;

	spi_write(context->spi, tx_buf, 2);

	nano_fiber_sem_give(&context->spi_sem);
	}


	static void eth_enc28j60_clear_eth_reg(struct device *dev, uint16_t reg_addr,
	uint8_t value)
	{
	struct eth_enc28j60_runtime *context = dev->driver_data;
	uint8_t tx_buf[2];

	nano_fiber_sem_take(&context->spi_sem, TICKS_UNLIMITED);

	tx_buf[0] = ENC28J60_SPI_BFC \| (reg_addr & 0xFF);
	tx_buf[1] = value;

	spi_write(context->spi, tx_buf, 2);

	nano_fiber_sem_give(&context->spi_sem);
	}

	static void eth_enc28j60_write_mem(struct device dev, uint8_t data_buffer,
	uint8_t buf_len)
	{
	struct eth_enc28j60_runtime *context = dev->driver_data;
	uint8_t tx_buf[MAX_BUFFER_LENGTH + 1];
	uint8_t *index_buf;
	uint16_t num_segments;
	uint16_t num_remanents;

	index_buf = data_buffer;
	num_segments = buf_len / MAX_BUFFER_LENGTH;
	num_remanents = buf_len - MAX_BUFFER_LENGTH * num_segments;

	nano_fiber_sem_take(&context->spi_sem, TICKS_UNLIMITED);

	tx_buf[0] = ENC28J60_SPI_WBM;

	for (int i = 0; i < num_segments;
	++i, index_buf += i * MAX_BUFFER_LENGTH) {

	memcpy(tx_buf + 1, index_buf, MAX_BUFFER_LENGTH);

	spi_write(context->spi, tx_buf, MAX_BUFFER_LENGTH + 1);

	}
	memcpy(tx_buf + 1, index_buf, num_remanents);

	spi_write(context->spi, tx_buf, num_remanents + 1);

	nano_fiber_sem_give(&context->spi_sem);
	}

	static void eth_enc28j60_read_mem(struct device dev, uint8_t data_buffer,
	uint8_t buf_len)
	{
	struct eth_enc28j60_runtime *context = dev->driver_data;
	uint8_t *index_buf;
	uint8_t tx_buf[MAX_BUFFER_LENGTH + 1];
	uint16_t num_segments;
	uint16_t num_remanents;

	index_buf = data_buffer;
	num_segments = buf_len / MAX_BUFFER_LENGTH;
	num_remanents = buf_len - MAX_BUFFER_LENGTH * num_segments;

	nano_fiber_sem_take(&context->spi_sem, TICKS_UNLIMITED);

	tx_buf[0] = ENC28J60_SPI_RBM;

	for (int i = 0; i < num_segments;
	++i, index_buf += i * MAX_BUFFER_LENGTH) {

	spi_transceive(context->spi, tx_buf, MAX_BUFFER_LENGTH + 1,
	tx_buf, MAX_BUFFER_LENGTH + 1);

	memcpy(index_buf, tx_buf + 1, MAX_BUFFER_LENGTH);
	}

	spi_transceive(context->spi, tx_buf, num_remanents + 1,
	tx_buf, num_remanents + 1);

	memcpy(index_buf, tx_buf + 1, num_remanents);

	nano_fiber_sem_give(&context->spi_sem);
	}

	static void eth_enc28j60_write_phy(struct device *dev, uint16_t reg_addr,
	int16_t data)
	{
	uint8_t data_mistat;

	eth_enc28j60_set_bank(dev, ENC28J60_REG_MIREGADR);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_MIREGADR, reg_addr);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_MIWRL, data & 0xFF);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_MIWRH, data >> 8);
	eth_enc28j60_set_bank(dev, ENC28J60_REG_MISTAT);

	do {
	/* wait 10.24 useconds */
	sys_thread_busy_wait(D10D24S);
	eth_enc28j60_read_reg(dev, ENC28J60_REG_MISTAT,
	&data_mistat);
	} while ((data_mistat & ENC28J60_BIT_MISTAT_BUSY));
	}

	static void eth_enc28j60_gpio_callback(struct device *dev,
	struct gpio_callback *cb,
	uint32_t pins)
	{
	struct eth_enc28j60_runtime *context =
	CONTAINER_OF(cb, struct eth_enc28j60_runtime, gpio_cb);

	nano_fiber_sem_give(&context->int_sem);
	}

	static void eth_enc28j60_init_buffers(struct device *dev)
	{
	uint8_t data_estat;

	/* Reception buffers initialization */
	eth_enc28j60_set_bank(dev, ENC28J60_REG_ERXSTL);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXSTL,
	ENC28J60_RXSTART & 0xFF);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXSTH,
	ENC28J60_RXSTART >> 8);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXRDPTL,
	ENC28J60_RXSTART & 0xFF);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXRDPTH,
	ENC28J60_RXSTART >> 8);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXNDL,
	ENC28J60_RXEND & 0xFF);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXNDH,
	ENC28J60_RXEND >> 8);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXSTL,
	ENC28J60_TXSTART & 0xFF);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXSTH,
	ENC28J60_TXSTART >> 8);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXNDL,
	ENC28J60_TXEND & 0xFF);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXNDH,
	ENC28J60_TXEND >> 8);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERDPTL,
	ENC28J60_RXSTART & 0xFF);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERDPTH,
	ENC28J60_RXSTART >> 8);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_EWRPTL,
	ENC28J60_TXSTART & 0xFF);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_EWRPTH,
	ENC28J60_TXSTART >> 8);

	eth_enc28j60_set_bank(dev, ENC28J60_REG_ERXFCON);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXFCON,
	ENC28J60_RECEIVE_FILTERS);

	/* Waiting for OST */
	do {
	/* wait 10.24 useconds */
	sys_thread_busy_wait(D10D24S);
	eth_enc28j60_read_reg(dev, ENC28J60_REG_ESTAT, &data_estat);
	} while (!(data_estat & ENC28J60_BIT_ESTAT_CLKRDY));
	}

	static void eth_enc28j60_init_mac(struct device *dev)
	{
	const struct eth_enc28j60_config *config = dev->config->config_info;
	uint8_t data_macon;
	uint8_t mac_address[6];

	eth_enc28j60_set_bank(dev, ENC28J60_REG_MACON1);

	/* Set MARXEN to enable MAC to receive frames */
	eth_enc28j60_read_reg(dev, ENC28J60_REG_MACON1, &data_macon);
	data_macon \|= ENC28J60_BIT_MACON1_MARXEN \| ENC28J60_BIT_MACON1_RXPAUS
	\| ENC28J60_BIT_MACON1_TXPAUS;
	eth_enc28j60_write_reg(dev, ENC28J60_REG_MACON1, data_macon);

	data_macon = ENC28J60_MAC_CONFIG;

	if (config->full_duplex) {
	data_macon \|= ENC28J60_BIT_MACON3_FULDPX;
	}

	eth_enc28j60_write_reg(dev, ENC28J60_REG_MACON3, data_macon);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_MAIPGL, ENC28J60_MAC_NBBIPGL);

	if (config->full_duplex) {
	eth_enc28j60_write_reg(dev, ENC28J60_REG_MAIPGH,
	ENC28J60_MAC_NBBIPGH);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_MABBIPG,
	ENC28J60_MAC_BBIPG_FD);
	} else {
	eth_enc28j60_write_reg(dev, ENC28J60_REG_MABBIPG,
	ENC28J60_MAC_BBIPG_HD);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_MACON4, 1 << 6);
	}

	/* Configure MAC address */
	mac_address[0] = MICROCHIP_OUI_B0;
	mac_address[1] = MICROCHIP_OUI_B1;
	mac_address[2] = MICROCHIP_OUI_B2;
	mac_address[3] = CONFIG_ETH_ENC28J60_0_MAC3;
	mac_address[4] = CONFIG_ETH_ENC28J60_0_MAC4;
	mac_address[5] = CONFIG_ETH_ENC28J60_0_MAC5;
	net_set_mac(mac_address, sizeof(mac_address));

	eth_enc28j60_set_bank(dev, ENC28J60_REG_MAADR0);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_MAADR0,
	CONFIG_ETH_ENC28J60_0_MAC5);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_MAADR1,
	CONFIG_ETH_ENC28J60_0_MAC4);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_MAADR2,
	CONFIG_ETH_ENC28J60_0_MAC3);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_MAADR3, MICROCHIP_OUI_B2);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_MAADR4, MICROCHIP_OUI_B1);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_MAADR5, MICROCHIP_OUI_B0);
	}

	static void eth_enc28j60_init_phy(struct device *dev)
	{
	const struct eth_enc28j60_config *config = dev->config->config_info;

	if (config->full_duplex) {
	eth_enc28j60_write_phy(dev, ENC28J60_PHY_PHCON1,
	ENC28J60_BIT_PHCON1_PDPXMD);
	eth_enc28j60_write_phy(dev, ENC28J60_PHY_PHCON2, 0x0);
	} else {
	eth_enc28j60_write_phy(dev, ENC28J60_PHY_PHCON1, 0x0);
	eth_enc28j60_write_phy(dev, ENC28J60_PHY_PHCON2,
	ENC28J60_BIT_PHCON2_HDLDIS);
	}
	}

	static int eth_enc28j60_init(struct device *dev)
	{
	const struct eth_enc28j60_config *config = dev->config->config_info;
	struct eth_enc28j60_runtime *context = dev->driver_data;
	struct spi_config spi_cfg;

	nano_sem_init(&context->spi_sem);
	nano_fiber_sem_give(&context->spi_sem);

	context->gpio = device_get_binding((char *)config->gpio_port);
	if (!context->gpio) {
	return -EINVAL;
	}

	context->spi = device_get_binding((char *)config->spi_port);
	if (!context->spi) {
	return -EINVAL;
	}

	/* Initialize GPIO */
	if (gpio_pin_configure(context->gpio, config->gpio_pin,
	(GPIO_DIR_IN \| GPIO_INT \| GPIO_INT_EDGE
	\| GPIO_INT_ACTIVE_LOW \| GPIO_INT_DEBOUNCE))) {
	return -EINVAL;
	}

	gpio_init_callback(&(context->gpio_cb), eth_enc28j60_gpio_callback,
	BIT(config->gpio_pin));

	if (gpio_add_callback(context->gpio, &(context->gpio_cb))) {
	return -EINVAL;
	}

	if (gpio_pin_enable_callback(context->gpio, config->gpio_pin)) {
	return -EINVAL;
	}

	/* Initialize SPI:
	* Mode: 0/0; Size: 8 bits; MSB
	*/
	spi_cfg.config = 8 << 4;
	spi_cfg.max_sys_freq = config->spi_freq;

	if (spi_configure(context->spi, &spi_cfg) < 0) {
	return -EIO;
	}

	if (spi_slave_select(context->spi, config->spi_slave) < 0) {
	return -EIO;
	}

	if (eth_enc28j60_soft_reset(dev)) {
	return -EIO;
	}

	/* Errata B7/2 */
	sys_thread_busy_wait(D10D24S);

	eth_enc28j60_init_buffers(dev);
	eth_enc28j60_init_mac(dev);
	eth_enc28j60_init_phy(dev);

	/* Enable interruptions */
	eth_enc28j60_set_eth_reg(dev, ENC28J60_REG_EIE, ENC28J60_BIT_EIE_INTIE);
	eth_enc28j60_set_eth_reg(dev, ENC28J60_REG_EIE, ENC28J60_BIT_EIE_PKTIE);

	/* Enable Reception */
	eth_enc28j60_set_eth_reg(dev, ENC28J60_REG_ECON1,
	ENC28J60_BIT_ECON1_RXEN);

	/* Register tx callback into IP stack */
	net_driver_ethernet_register_tx(eth_net_tx);

	/* Initialize semaphores */
	nano_sem_init(&context->tx_sem);
	nano_sem_init(&context->int_sem);
	nano_sem_give(&context->tx_sem);

	/* Start interruption-poll fiber */
	fiber_start(context->fiber_stack, ENC28J60_FIBER_STACK_SIZE,
	enc28j60_fiber_main, (int)dev, 0,
	ENC28J60_FIBER_PRIORITY, 0);

	return 0;
	}

	static int eth_enc28j60_tx(struct device dev, uint8_t buf, uint16_t len)
	{
	struct eth_enc28j60_runtime *context = dev->driver_data;
	uint16_t tx_bufaddr = ENC28J60_TXSTART;
	uint8_t per_packet_control;
	uint16_t tx_bufaddr_end;
	uint8_t tx_end;

	nano_fiber_sem_take(&context->tx_sem, TICKS_UNLIMITED);

	/* Latest errata sheet: DS80349C
	* always reset transmit logic (Errata Issue 12)
	* the Microchip TCP/IP stack implementation used to first check
	* whether TXERIF is set and only then reset the transmit logic
	* but this has been changed in later versions; possibly they
	* have a reason for this; they don't mention this in the errata
	* sheet
	*/
	eth_enc28j60_set_eth_reg(dev, ENC28J60_REG_ECON1,
	ENC28J60_BIT_ECON1_TXRST);
	eth_enc28j60_clear_eth_reg(dev, ENC28J60_REG_ECON1,
	ENC28J60_BIT_ECON1_TXRST);

	/* Write the buffer content into the transmission buffer */
	eth_enc28j60_set_bank(dev, ENC28J60_REG_ETXSTL);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_EWRPTL, tx_bufaddr & 0xFF);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_EWRPTH, tx_bufaddr >> 8);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXSTL, tx_bufaddr & 0xFF);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXSTH, tx_bufaddr >> 8);

	/* Write the data into the buffer */
	per_packet_control = ENC28J60_PPCTL_BYTE;
	eth_enc28j60_write_mem(dev, &per_packet_control, 1);
	eth_enc28j60_write_mem(dev, buf, len);

	tx_bufaddr_end = tx_bufaddr + len;
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXNDL,
	tx_bufaddr_end & 0xFF);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ETXNDH, tx_bufaddr_end >> 8);

	/* Signal ENC28J60 to send the buffer */
	eth_enc28j60_set_eth_reg(dev, ENC28J60_REG_ECON1,
	ENC28J60_BIT_ECON1_TXRTS);

	do {
	/* wait 10.24 useconds */
	sys_thread_busy_wait(D10D24S);
	eth_enc28j60_read_reg(dev, ENC28J60_REG_EIR, &tx_end);
	tx_end &= ENC28J60_BIT_EIR_TXIF;
	} while (!tx_end);

	eth_enc28j60_read_reg(dev, ENC28J60_REG_EIR, &tx_end);

	nano_sem_give(&context->tx_sem);

	if (tx_end & ENC28J60_BIT_ESTAT_TXABRT) {
	return -1;
	}

	return 0;
	}

	static int eth_enc28j60_rx(struct device *dev)
	{
	struct eth_enc28j60_runtime *context = dev->driver_data;
	uint8_t econ1_bkup;
	uint8_t counter;

	/* Errata 6. The Receive Packet Pending Interrupt Flag (EIR.PKTIF)
	* does not reliably/accurately report the status of pending packet.
	* Use EPKTCNT register instead.
	*/

	/* Backup ECON1 register in case the rx interrupted a tx process */
	eth_enc28j60_read_reg(dev, ENC28J60_REG_ECON1, &econ1_bkup);

	do {
	uint8_t *reception_buf = NULL;
	uint16_t frm_len = 0;
	uint16_t next_packet;
	struct net_buf *buf;
	uint8_t np[2];

	/* Read address for next packet */
	eth_enc28j60_read_mem(dev, np, 2);
	next_packet = np[0] \| (uint16_t)np[1] << 8;

	/* Errata 14. Even values in ERXRDPT
	* may corrupt receive buffer.
	*/
	if (next_packet == 0) {
	next_packet = ENC28J60_RXEND;
	} else if (!(next_packet & 0x01)) {
	next_packet--;
	}

	/* Read reception status vector */
	eth_enc28j60_read_mem(dev, context->rx_rsv, 4);

	/* Get the frame length from the rx status vector */
	frm_len = (context->rx_rsv[1] << 8) \| context->rx_rsv[0];

	if (frm_len > (UIP_BUFSIZE)) {
	goto done;
	}
	/* Get the frame from the buffer */
	buf = ip_buf_get_reserve_rx(0);

	reception_buf = net_buf_add(buf, frm_len);

	if (reception_buf == NULL) {
	frm_len = 0;
	goto done;
	}

	eth_enc28j60_read_mem(dev, reception_buf, frm_len);
	uip_len(buf) = frm_len;

	/* Register the buffer frame with the IP stack */
	net_driver_ethernet_recv(buf);
	done:
	/* Free buffer memory and decrement rx counter */
	eth_enc28j60_set_bank(dev, ENC28J60_REG_ERXRDPTL);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXRDPTL,
	next_packet & 0xFF);
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ERXRDPTH,
	next_packet >> 8);
	eth_enc28j60_set_eth_reg(dev, ENC28J60_REG_ECON2,
	ENC28J60_BIT_ECON2_PKTDEC);

	/* Call receive callback */
	if (context->receive_callback) {
	context->receive_callback(reception_buf, frm_len);
	}

	/* Check if there are frames to clean from the buffer */
	eth_enc28j60_read_reg(dev, ENC28J60_REG_EPKTCNT, &counter);
	} while (counter);

	/* Recover ECON1 register */
	eth_enc28j60_write_reg(dev, ENC28J60_REG_ECON1, econ1_bkup);

	return 0;
	}

	void eth_enc28j60_reg_cb(struct device *dev,
	void (cb)(uint8_t buffer, uint16_t len))
	{
	struct eth_enc28j60_runtime *context = dev->driver_data;

	context->receive_callback = cb;
	}

	static void enc28j60_fiber_main(int arg1, int unused)
	{
	struct device dev = (struct device )arg1;
	struct eth_enc28j60_runtime *context;
	uint8_t int_stat;

	ARG_UNUSED(unused);

	context = dev->driver_data;

	while (1) {
	nano_fiber_sem_take(&context->int_sem, TICKS_UNLIMITED);
	eth_enc28j60_read_reg(dev, ENC28J60_REG_EIR, &int_stat);

	if (int_stat & ENC28J60_BIT_EIR_PKTIF) {
	eth_enc28j60_rx(dev);
	/* Clear rx interruption flag */
	eth_enc28j60_clear_eth_reg(dev, ENC28J60_REG_EIR,
	ENC28J60_BIT_EIR_PKTIF
	\| ENC28J60_BIT_EIR_RXERIF);
	}
	}
	}

	static struct eth_driver_api api_funcs = {
	.send = eth_enc28j60_tx,
	.register_callback = eth_enc28j60_reg_cb,
	};

	#ifdef CONFIG_ETH_ENC28J60_0
	static struct eth_enc28j60_runtime eth_enc28j60_0_runtime = {
	.receive_callback = NULL,
	};

	static const struct eth_enc28j60_config eth_enc28j60_0_config = {
	.gpio_port = CONFIG_ETH_ENC28J60_0_GPIO_PORT_NAME,
	.gpio_pin = CONFIG_ETH_ENC28J60_0_GPIO_PIN,
	.spi_port = CONFIG_ETH_ENC28J60_0_SPI_PORT_NAME,
	.spi_freq = CONFIG_ETH_ENC28J60_0_SPI_BUS_FREQ,
	.spi_slave = CONFIG_ETH_ENC28J60_0_SLAVE,
	.full_duplex = CONFIG_ETH_EN28J60_0_FULL_DUPLEX,
	};

	DEVICE_AND_API_INIT(eth_enc28j60_0, CONFIG_ETH_ENC28J60_0_NAME,
	&eth_enc28j60_init, &eth_enc28j60_0_runtime,
	&eth_enc28j60_0_config, SECONDARY,
	CONFIG_ETH_ENC28J60_0_INIT_PRIORITY, &api_funcs);

	static int eth_net_tx(struct net_buf *buf)
	{
	return eth_enc28j60_tx(DEVICE_GET(eth_enc28j60_0),
	uip_buf(buf), uip_len(buf));
	}

	#endif /* CONFIG_ETH_ENC28J60_0 */