linux/drivers/net/ethernet/davicom/dm9051.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2022 Davicom Semiconductor,Inc.
 * Davicom DM9051 SPI Fast Ethernet Linux driver
 */

#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/interrupt.h>
#include <linux/iopoll.h>
#include <linux/irq.h>
#include <linux/mii.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/phy.h>
#include <linux/regmap.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/spi/spi.h>
#include <linux/types.h>

#include "dm9051.h"

#define DRVNAME_9051	"dm9051"

/**
 * struct rx_ctl_mach - rx activities record
 * @status_err_counter: rx status error counter
 * @large_err_counter: rx get large packet length error counter
 * @rx_err_counter: receive packet error counter
 * @tx_err_counter: transmit packet error counter
 * @fifo_rst_counter: reset operation counter
 *
 * To keep track for the driver operation statistics
 */
struct rx_ctl_mach {
	u16				status_err_counter;
	u16				large_err_counter;
	u16				rx_err_counter;
	u16				tx_err_counter;
	u16				fifo_rst_counter;
};

/**
 * struct dm9051_rxctrl - dm9051 driver rx control
 * @hash_table: Multicast hash-table data
 * @rcr_all: KS_RXCR1 register setting
 *
 * The settings needs to control the receive filtering
 * such as the multicast hash-filter and the receive register settings
 */
struct dm9051_rxctrl {
	u16				hash_table[4];
	u8				rcr_all;
};

/**
 * struct dm9051_rxhdr - rx packet data header
 * @headbyte: lead byte equal to 0x01 notifies a valid packet
 * @status: status bits for the received packet
 * @rxlen: packet length
 *
 * The Rx packed, entered into the FIFO memory, start with these
 * four bytes which is the Rx header, followed by the ethernet
 * packet data and ends with an appended 4-byte CRC data.
 * Both Rx packet and CRC data are for check purpose and finally
 * are dropped by this driver
 */
struct dm9051_rxhdr {
	u8				headbyte;
	u8				status;
	__le16				rxlen;
};

/**
 * struct board_info - maintain the saved data
 * @spidev: spi device structure
 * @ndev: net device structure
 * @mdiobus: mii bus structure
 * @phydev: phy device structure
 * @txq: tx queue structure
 * @regmap_dm: regmap for register read/write
 * @regmap_dmbulk: extra regmap for bulk read/write
 * @rxctrl_work: Work queue for updating RX mode and multicast lists
 * @tx_work: Work queue for tx packets
 * @pause: ethtool pause parameter structure
 * @spi_lockm: between threads lock structure
 * @reg_mutex: regmap access lock structure
 * @bc: rx control statistics structure
 * @rxhdr: rx header structure
 * @rctl: rx control setting structure
 * @msg_enable: message level value
 * @imr_all: to store operating imr value for register DM9051_IMR
 * @lcr_all: to store operating rcr value for register DM9051_LMCR
 *
 * The saved data variables, keep up to date for retrieval back to use
 */
struct board_info {
	u32				msg_enable;
	struct spi_device		*spidev;
	struct net_device		*ndev;
	struct mii_bus			*mdiobus;
	struct phy_device		*phydev;
	struct sk_buff_head		txq;
	struct regmap			*regmap_dm;
	struct regmap			*regmap_dmbulk;
	struct work_struct		rxctrl_work;
	struct work_struct		tx_work;
	struct ethtool_pauseparam	pause;
	struct mutex			spi_lockm;
	struct mutex			reg_mutex;
	struct rx_ctl_mach		bc;
	struct dm9051_rxhdr		rxhdr;
	struct dm9051_rxctrl		rctl;
	u8				imr_all;
	u8				lcr_all;
};

static int dm9051_set_reg(struct board_info *db, unsigned int reg, unsigned int val)
{
	int ret;

	ret = regmap_write(db->regmap_dm, reg, val);
	if (ret < 0)
		netif_err(db, drv, db->ndev, "%s: error %d set reg %02x\n",
			  __func__, ret, reg);
	return ret;
}

static int dm9051_update_bits(struct board_info *db, unsigned int reg, unsigned int mask,
			      unsigned int val)
{
	int ret;

	ret = regmap_update_bits(db->regmap_dm, reg, mask, val);
	if (ret < 0)
		netif_err(db, drv, db->ndev, "%s: error %d update bits reg %02x\n",
			  __func__, ret, reg);
	return ret;
}

/* skb buffer exhausted, just discard the received data
 */
static int dm9051_dumpblk(struct board_info *db, u8 reg, size_t count)
{
	struct net_device *ndev = db->ndev;
	unsigned int rb;
	int ret;

	/* no skb buffer,
	 * both reg and &rb must be noinc,
	 * read once one byte via regmap_read
	 */
	do {
		ret = regmap_read(db->regmap_dm, reg, &rb);
		if (ret < 0) {
			netif_err(db, drv, ndev, "%s: error %d dumping read reg %02x\n",
				  __func__, ret, reg);
			break;
		}
	} while (--count);

	return ret;
}

static int dm9051_set_regs(struct board_info *db, unsigned int reg, const void *val,
			   size_t val_count)
{
	int ret;

	ret = regmap_bulk_write(db->regmap_dmbulk, reg, val, val_count);
	if (ret < 0)
		netif_err(db, drv, db->ndev, "%s: error %d bulk writing regs %02x\n",
			  __func__, ret, reg);
	return ret;
}

static int dm9051_get_regs(struct board_info *db, unsigned int reg, void *val,
			   size_t val_count)
{
	int ret;

	ret = regmap_bulk_read(db->regmap_dmbulk, reg, val, val_count);
	if (ret < 0)
		netif_err(db, drv, db->ndev, "%s: error %d bulk reading regs %02x\n",
			  __func__, ret, reg);
	return ret;
}

static int dm9051_write_mem(struct board_info *db, unsigned int reg, const void *buff,
			    size_t len)
{
	int ret;

	ret = regmap_noinc_write(db->regmap_dm, reg, buff, len);
	if (ret < 0)
		netif_err(db, drv, db->ndev, "%s: error %d noinc writing regs %02x\n",
			  __func__, ret, reg);
	return ret;
}

static int dm9051_read_mem(struct board_info *db, unsigned int reg, void *buff,
			   size_t len)
{
	int ret;

	ret = regmap_noinc_read(db->regmap_dm, reg, buff, len);
	if (ret < 0)
		netif_err(db, drv, db->ndev, "%s: error %d noinc reading regs %02x\n",
			  __func__, ret, reg);
	return ret;
}

/* waiting tx-end rather than tx-req
 * got faster
 */
static int dm9051_nsr_poll(struct board_info *db)
{
	unsigned int mval;
	int ret;

	ret = regmap_read_poll_timeout(db->regmap_dm, DM9051_NSR, mval,
				       mval & (NSR_TX2END | NSR_TX1END), 1, 20);
	if (ret == -ETIMEDOUT)
		netdev_err(db->ndev, "timeout in checking for tx end\n");
	return ret;
}

static int dm9051_epcr_poll(struct board_info *db)
{
	unsigned int mval;
	int ret;

	ret = regmap_read_poll_timeout(db->regmap_dm, DM9051_EPCR, mval,
				       !(mval & EPCR_ERRE), 100, 10000);
	if (ret == -ETIMEDOUT)
		netdev_err(db->ndev, "eeprom/phy in processing get timeout\n");
	return ret;
}

static int dm9051_irq_flag(struct board_info *db)
{
	struct spi_device *spi = db->spidev;
	int irq_type = irq_get_trigger_type(spi->irq);

	if (irq_type)
		return irq_type;

	return IRQF_TRIGGER_LOW;
}

static unsigned int dm9051_intcr_value(struct board_info *db)
{
	return (dm9051_irq_flag(db) == IRQF_TRIGGER_LOW) ?
		INTCR_POL_LOW : INTCR_POL_HIGH;
}

static int dm9051_set_fcr(struct board_info *db)
{
	u8 fcr = 0;

	if (db->pause.rx_pause)
		fcr |= FCR_BKPM | FCR_FLCE;
	if (db->pause.tx_pause)
		fcr |= FCR_TXPEN;

	return dm9051_set_reg(db, DM9051_FCR, fcr);
}

static int dm9051_set_recv(struct board_info *db)
{
	int ret;

	ret = dm9051_set_regs(db, DM9051_MAR, db->rctl.hash_table, sizeof(db->rctl.hash_table));
	if (ret)
		return ret;

	return dm9051_set_reg(db, DM9051_RCR, db->rctl.rcr_all); /* enable rx */
}

static int dm9051_core_reset(struct board_info *db)
{
	int ret;

	db->bc.fifo_rst_counter++;

	ret = regmap_write(db->regmap_dm, DM9051_NCR, NCR_RST); /* NCR reset */
	if (ret)
		return ret;
	ret = regmap_write(db->regmap_dm, DM9051_MBNDRY, MBNDRY_BYTE); /* MemBound */
	if (ret)
		return ret;
	ret = regmap_write(db->regmap_dm, DM9051_PPCR, PPCR_PAUSE_COUNT); /* Pause Count */
	if (ret)
		return ret;
	ret = regmap_write(db->regmap_dm, DM9051_LMCR, db->lcr_all); /* LEDMode1 */
	if (ret)
		return ret;

	return dm9051_set_reg(db, DM9051_INTCR, dm9051_intcr_value(db));
}

static int dm9051_update_fcr(struct board_info *db)
{
	u8 fcr = 0;

	if (db->pause.rx_pause)
		fcr |= FCR_BKPM | FCR_FLCE;
	if (db->pause.tx_pause)
		fcr |= FCR_TXPEN;

	return dm9051_update_bits(db, DM9051_FCR, FCR_RXTX_BITS, fcr);
}

static int dm9051_disable_interrupt(struct board_info *db)
{
	return dm9051_set_reg(db, DM9051_IMR, IMR_PAR); /* disable int */
}

static int dm9051_enable_interrupt(struct board_info *db)
{
	return dm9051_set_reg(db, DM9051_IMR, db->imr_all); /* enable int */
}

static int dm9051_stop_mrcmd(struct board_info *db)
{
	return dm9051_set_reg(db, DM9051_ISR, ISR_STOP_MRCMD); /* to stop mrcmd */
}

static int dm9051_clear_interrupt(struct board_info *db)
{
	return dm9051_update_bits(db, DM9051_ISR, ISR_CLR_INT, ISR_CLR_INT);
}

static int dm9051_eeprom_read(struct board_info *db, int offset, u8 *to)
{
	int ret;

	ret = regmap_write(db->regmap_dm, DM9051_EPAR, offset);
	if (ret)
		return ret;

	ret = regmap_write(db->regmap_dm, DM9051_EPCR, EPCR_ERPRR);
	if (ret)
		return ret;

	ret = dm9051_epcr_poll(db);
	if (ret)
		return ret;

	ret = regmap_write(db->regmap_dm, DM9051_EPCR, 0);
	if (ret)
		return ret;

	return regmap_bulk_read(db->regmap_dmbulk, DM9051_EPDRL, to, 2);
}

static int dm9051_eeprom_write(struct board_info *db, int offset, u8 *data)
{
	int ret;

	ret = regmap_write(db->regmap_dm, DM9051_EPAR, offset);
	if (ret)
		return ret;

	ret = regmap_bulk_write(db->regmap_dmbulk, DM9051_EPDRL, data, 2);
	if (ret < 0)
		return ret;

	ret = regmap_write(db->regmap_dm, DM9051_EPCR, EPCR_WEP | EPCR_ERPRW);
	if (ret)
		return ret;

	ret = dm9051_epcr_poll(db);
	if (ret)
		return ret;

	return regmap_write(db->regmap_dm, DM9051_EPCR, 0);
}

static int dm9051_phyread(void *context, unsigned int reg, unsigned int *val)
{
	struct board_info *db = context;
	int ret;

	ret = regmap_write(db->regmap_dm, DM9051_EPAR, DM9051_PHY | reg);
	if (ret)
		return ret;

	ret = regmap_write(db->regmap_dm, DM9051_EPCR, EPCR_ERPRR | EPCR_EPOS);
	if (ret)
		return ret;

	ret = dm9051_epcr_poll(db);
	if (ret)
		return ret;

	ret = regmap_write(db->regmap_dm, DM9051_EPCR, 0);
	if (ret)
		return ret;

	/* this is a 4 bytes data, clear to zero since following regmap_bulk_read
	 * only fill lower 2 bytes
	 */
	*val = 0;
	return regmap_bulk_read(db->regmap_dmbulk, DM9051_EPDRL, val, 2);
}

static int dm9051_phywrite(void *context, unsigned int reg, unsigned int val)
{
	struct board_info *db = context;
	int ret;

	ret = regmap_write(db->regmap_dm, DM9051_EPAR, DM9051_PHY | reg);
	if (ret)
		return ret;

	ret = regmap_bulk_write(db->regmap_dmbulk, DM9051_EPDRL, &val, 2);
	if (ret < 0)
		return ret;

	ret = regmap_write(db->regmap_dm, DM9051_EPCR, EPCR_EPOS | EPCR_ERPRW);
	if (ret)
		return ret;

	ret = dm9051_epcr_poll(db);
	if (ret)
		return ret;

	return regmap_write(db->regmap_dm, DM9051_EPCR, 0);
}

static int dm9051_mdio_read(struct mii_bus *bus, int addr, int regnum)
{
	struct board_info *db = bus->priv;
	unsigned int val = 0xffff;
	int ret;

	if (addr == DM9051_PHY_ADDR) {
		ret = dm9051_phyread(db, regnum, &val);
		if (ret)
			return ret;
	}

	return val;
}

static int dm9051_mdio_write(struct mii_bus *bus, int addr, int regnum, u16 val)
{
	struct board_info *db = bus->priv;

	if (addr == DM9051_PHY_ADDR)
		return dm9051_phywrite(db, regnum, val);

	return -ENODEV;
}

static void dm9051_reg_lock_mutex(void *dbcontext)
{
	struct board_info *db = dbcontext;

	mutex_lock(&db->reg_mutex);
}

static void dm9051_reg_unlock_mutex(void *dbcontext)
{
	struct board_info *db = dbcontext;

	mutex_unlock(&db->reg_mutex);
}

static struct regmap_config regconfigdm = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = 0xff,
	.reg_stride = 1,
	.cache_type = REGCACHE_NONE,
	.read_flag_mask = 0,
	.write_flag_mask = DM_SPI_WR,
	.val_format_endian = REGMAP_ENDIAN_LITTLE,
	.lock = dm9051_reg_lock_mutex,
	.unlock = dm9051_reg_unlock_mutex,
};

static struct regmap_config regconfigdmbulk = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = 0xff,
	.reg_stride = 1,
	.cache_type = REGCACHE_NONE,
	.read_flag_mask = 0,
	.write_flag_mask = DM_SPI_WR,
	.val_format_endian = REGMAP_ENDIAN_LITTLE,
	.lock = dm9051_reg_lock_mutex,
	.unlock = dm9051_reg_unlock_mutex,
	.use_single_read = true,
	.use_single_write = true,
};

static int dm9051_map_init(struct spi_device *spi, struct board_info *db)
{
	/* create two regmap instances,
	 * split read/write and bulk_read/bulk_write to individual regmap
	 * to resolve regmap execution confliction problem
	 */
	regconfigdm.lock_arg = db;
	db->regmap_dm = devm_regmap_init_spi(db->spidev, &regconfigdm);
	if (IS_ERR(db->regmap_dm))
		return PTR_ERR(db->regmap_dm);

	regconfigdmbulk.lock_arg = db;
	db->regmap_dmbulk = devm_regmap_init_spi(db->spidev, &regconfigdmbulk);
	if (IS_ERR(db->regmap_dmbulk))
		return PTR_ERR(db->regmap_dmbulk);

	return 0;
}

static int dm9051_map_chipid(struct board_info *db)
{
	struct device *dev = &db->spidev->dev;
	unsigned short wid;
	u8 buff[6];
	int ret;

	ret = dm9051_get_regs(db, DM9051_VIDL, buff, sizeof(buff));
	if (ret < 0)
		return ret;

	wid = get_unaligned_le16(buff + 2);
	if (wid != DM9051_ID) {
		dev_err(dev, "chipid error as %04x !\n", wid);
		return -ENODEV;
	}

	dev_info(dev, "chip %04x found\n", wid);
	return 0;
}

/* Read DM9051_PAR registers which is the mac address loaded from EEPROM while power-on
 */
static int dm9051_map_etherdev_par(struct net_device *ndev, struct board_info *db)
{
	u8 addr[ETH_ALEN];
	int ret;

	ret = dm9051_get_regs(db, DM9051_PAR, addr, sizeof(addr));
	if (ret < 0)
		return ret;

	if (!is_valid_ether_addr(addr)) {
		eth_hw_addr_random(ndev);

		ret = dm9051_set_regs(db, DM9051_PAR, ndev->dev_addr, sizeof(ndev->dev_addr));
		if (ret < 0)
			return ret;

		dev_dbg(&db->spidev->dev, "Use random MAC address\n");
		return 0;
	}

	eth_hw_addr_set(ndev, addr);
	return 0;
}

/* ethtool-ops
 */
static void dm9051_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
{
	strscpy(info->driver, DRVNAME_9051, sizeof(info->driver));
}

static void dm9051_set_msglevel(struct net_device *ndev, u32 value)
{
	struct board_info *db = to_dm9051_board(ndev);

	db->msg_enable = value;
}

static u32 dm9051_get_msglevel(struct net_device *ndev)
{
	struct board_info *db = to_dm9051_board(ndev);

	return db->msg_enable;
}

static int dm9051_get_eeprom_len(struct net_device *dev)
{
	return 128;
}

static int dm9051_get_eeprom(struct net_device *ndev,
			     struct ethtool_eeprom *ee, u8 *data)
{
	struct board_info *db = to_dm9051_board(ndev);
	int offset = ee->offset;
	int len = ee->len;
	int i, ret;

	if ((len | offset) & 1)
		return -EINVAL;

	ee->magic = DM_EEPROM_MAGIC;

	for (i = 0; i < len; i += 2) {
		ret = dm9051_eeprom_read(db, (offset + i) / 2, data + i);
		if (ret)
			break;
	}
	return ret;
}

static int dm9051_set_eeprom(struct net_device *ndev,
			     struct ethtool_eeprom *ee, u8 *data)
{
	struct board_info *db = to_dm9051_board(ndev);
	int offset = ee->offset;
	int len = ee->len;
	int i, ret;

	if ((len | offset) & 1)
		return -EINVAL;

	if (ee->magic != DM_EEPROM_MAGIC)
		return -EINVAL;

	for (i = 0; i < len; i += 2) {
		ret = dm9051_eeprom_write(db, (offset + i) / 2, data + i);
		if (ret)
			break;
	}
	return ret;
}

static void dm9051_get_pauseparam(struct net_device *ndev,
				  struct ethtool_pauseparam *pause)
{
	struct board_info *db = to_dm9051_board(ndev);

	*pause = db->pause;
}

static int dm9051_set_pauseparam(struct net_device *ndev,
				 struct ethtool_pauseparam *pause)
{
	struct board_info *db = to_dm9051_board(ndev);

	db->pause = *pause;

	if (pause->autoneg == AUTONEG_DISABLE)
		return dm9051_update_fcr(db);

	phy_set_sym_pause(db->phydev, pause->rx_pause, pause->tx_pause,
			  pause->autoneg);
	phy_start_aneg(db->phydev);
	return 0;
}

static const struct ethtool_ops dm9051_ethtool_ops = {
	.get_drvinfo = dm9051_get_drvinfo,
	.get_link_ksettings = phy_ethtool_get_link_ksettings,
	.set_link_ksettings = phy_ethtool_set_link_ksettings,
	.get_msglevel = dm9051_get_msglevel,
	.set_msglevel = dm9051_set_msglevel,
	.nway_reset = phy_ethtool_nway_reset,
	.get_link = ethtool_op_get_link,
	.get_eeprom_len = dm9051_get_eeprom_len,
	.get_eeprom = dm9051_get_eeprom,
	.set_eeprom = dm9051_set_eeprom,
	.get_pauseparam = dm9051_get_pauseparam,
	.set_pauseparam = dm9051_set_pauseparam,
};

static int dm9051_all_start(struct board_info *db)
{
	int ret;

	/* GPR power on of the internal phy
	 */
	ret = dm9051_set_reg(db, DM9051_GPR, 0);
	if (ret)
		return ret;

	/* dm9051 chip registers could not be accessed within 1 ms
	 * after GPR power on, delay 1 ms is essential
	 */
	msleep(1);

	ret = dm9051_core_reset(db);
	if (ret)
		return ret;

	return dm9051_enable_interrupt(db);
}

static int dm9051_all_stop(struct board_info *db)
{
	int ret;

	/* GPR power off of the internal phy,
	 * The internal phy still could be accessed after this GPR power off control
	 */
	ret = dm9051_set_reg(db, DM9051_GPR, GPR_PHY_OFF);
	if (ret)
		return ret;

	return dm9051_set_reg(db, DM9051_RCR, RCR_RX_DISABLE);
}

/* fifo reset while rx error found
 */
static int dm9051_all_restart(struct board_info *db)
{
	struct net_device *ndev = db->ndev;
	int ret;

	ret = dm9051_core_reset(db);
	if (ret)
		return ret;

	ret = dm9051_enable_interrupt(db);
	if (ret)
		return ret;

	netdev_dbg(ndev, " rxstatus_Er & rxlen_Er %d, RST_c %d\n",
		   db->bc.status_err_counter + db->bc.large_err_counter,
		   db->bc.fifo_rst_counter);

	ret = dm9051_set_recv(db);
	if (ret)
		return ret;

	return dm9051_set_fcr(db);
}

/* read packets from the fifo memory
 * return value,
 *  > 0 - read packet number, caller can repeat the rx operation
 *    0 - no error, caller need stop further rx operation
 *  -EBUSY - read data error, caller escape from rx operation
 */
static int dm9051_loop_rx(struct board_info *db)
{
	struct net_device *ndev = db->ndev;
	unsigned int rxbyte;
	int ret, rxlen;
	struct sk_buff *skb;
	u8 *rdptr;
	int scanrr = 0;

	do {
		ret = dm9051_read_mem(db, DM_SPI_MRCMDX, &rxbyte, 2);
		if (ret)
			return ret;

		if ((rxbyte & GENMASK(7, 0)) != DM9051_PKT_RDY)
			break; /* exhaust-empty */

		ret = dm9051_read_mem(db, DM_SPI_MRCMD, &db->rxhdr, DM_RXHDR_SIZE);
		if (ret)
			return ret;

		ret = dm9051_stop_mrcmd(db);
		if (ret)
			return ret;

		rxlen = le16_to_cpu(db->rxhdr.rxlen);
		if (db->rxhdr.status & RSR_ERR_BITS || rxlen > DM9051_PKT_MAX) {
			netdev_dbg(ndev, "rxhdr-byte (%02x)\n",
				   db->rxhdr.headbyte);

			if (db->rxhdr.status & RSR_ERR_BITS) {
				db->bc.status_err_counter++;
				netdev_dbg(ndev, "check rxstatus-error (%02x)\n",
					   db->rxhdr.status);
			} else {
				db->bc.large_err_counter++;
				netdev_dbg(ndev, "check rxlen large-error (%d > %d)\n",
					   rxlen, DM9051_PKT_MAX);
			}
			return dm9051_all_restart(db);
		}

		skb = dev_alloc_skb(rxlen);
		if (!skb) {
			ret = dm9051_dumpblk(db, DM_SPI_MRCMD, rxlen);
			if (ret)
				return ret;
			return scanrr;
		}

		rdptr = skb_put(skb, rxlen - 4);
		ret = dm9051_read_mem(db, DM_SPI_MRCMD, rdptr, rxlen);
		if (ret) {
			db->bc.rx_err_counter++;
			dev_kfree_skb(skb);
			return ret;
		}

		ret = dm9051_stop_mrcmd(db);
		if (ret) {
			dev_kfree_skb(skb);
			return ret;
		}

		skb->protocol = eth_type_trans(skb, db->ndev);
		if (db->ndev->features & NETIF_F_RXCSUM)
			skb_checksum_none_assert(skb);
		netif_rx(skb);
		db->ndev->stats.rx_bytes += rxlen;
		db->ndev->stats.rx_packets++;
		scanrr++;
	} while (!ret);

	return scanrr;
}

/* transmit a packet,
 * return value,
 *   0 - succeed
 *  -ETIMEDOUT - timeout error
 */
static int dm9051_single_tx(struct board_info *db, u8 *buff, unsigned int len)
{
	int ret;

	ret = dm9051_nsr_poll(db);
	if (ret)
		return ret;

	ret = dm9051_write_mem(db, DM_SPI_MWCMD, buff, len);
	if (ret)
		return ret;

	ret = dm9051_set_regs(db, DM9051_TXPLL, &len, 2);
	if (ret < 0)
		return ret;

	return dm9051_set_reg(db, DM9051_TCR, TCR_TXREQ);
}

static int dm9051_loop_tx(struct board_info *db)
{
	struct net_device *ndev = db->ndev;
	int ntx = 0;
	int ret;

	while (!skb_queue_empty(&db->txq)) {
		struct sk_buff *skb;
		unsigned int len;

		skb = skb_dequeue(&db->txq);
		if (skb) {
			ntx++;
			ret = dm9051_single_tx(db, skb->data, skb->len);
			len = skb->len;
			dev_kfree_skb(skb);
			if (ret < 0) {
				db->bc.tx_err_counter++;
				return 0;
			}
			ndev->stats.tx_bytes += len;
			ndev->stats.tx_packets++;
		}

		if (netif_queue_stopped(ndev) &&
		    (skb_queue_len(&db->txq) < DM9051_TX_QUE_LO_WATER))
			netif_wake_queue(ndev);
	}

	return ntx;
}

static irqreturn_t dm9051_rx_threaded_irq(int irq, void *pw)
{
	struct board_info *db = pw;
	int result, result_tx;

	mutex_lock(&db->spi_lockm);

	result = dm9051_disable_interrupt(db);
	if (result)
		goto out_unlock;

	result = dm9051_clear_interrupt(db);
	if (result)
		goto out_unlock;

	do {
		result = dm9051_loop_rx(db); /* threaded irq rx */
		if (result < 0)
			goto out_unlock;
		result_tx = dm9051_loop_tx(db); /* more tx better performance */
		if (result_tx < 0)
			goto out_unlock;
	} while (result > 0);

	dm9051_enable_interrupt(db);

	/* To exit and has mutex unlock while rx or tx error
	 */
out_unlock:
	mutex_unlock(&db->spi_lockm);

	return IRQ_HANDLED;
}

static void dm9051_tx_delay(struct work_struct *work)
{
	struct board_info *db = container_of(work, struct board_info, tx_work);
	int result;

	mutex_lock(&db->spi_lockm);

	result = dm9051_loop_tx(db);
	if (result < 0)
		netdev_err(db->ndev, "transmit packet error\n");

	mutex_unlock(&db->spi_lockm);
}

static void dm9051_rxctl_delay(struct work_struct *work)
{
	struct board_info *db = container_of(work, struct board_info, rxctrl_work);
	struct net_device *ndev = db->ndev;
	int result;

	mutex_lock(&db->spi_lockm);

	result = dm9051_set_regs(db, DM9051_PAR, ndev->dev_addr, sizeof(ndev->dev_addr));
	if (result < 0)
		goto out_unlock;

	dm9051_set_recv(db);

	/* To has mutex unlock and return from this function if regmap function fail
	 */
out_unlock:
	mutex_unlock(&db->spi_lockm);
}

/* Open network device
 * Called when the network device is marked active, such as a user executing
 * 'ifconfig up' on the device
 */
static int dm9051_open(struct net_device *ndev)
{
	struct board_info *db = to_dm9051_board(ndev);
	struct spi_device *spi = db->spidev;
	int ret;

	db->imr_all = IMR_PAR | IMR_PRM;
	db->lcr_all = LMCR_MODE1;
	db->rctl.rcr_all = RCR_DIS_LONG | RCR_DIS_CRC | RCR_RXEN;
	memset(db->rctl.hash_table, 0, sizeof(db->rctl.hash_table));

	ndev->irq = spi->irq; /* by dts */
	ret = request_threaded_irq(spi->irq, NULL, dm9051_rx_threaded_irq,
				   dm9051_irq_flag(db) | IRQF_ONESHOT,
				   ndev->name, db);
	if (ret < 0) {
		netdev_err(ndev, "failed to get irq\n");
		return ret;
	}

	phy_support_sym_pause(db->phydev);
	phy_start(db->phydev);

	/* flow control parameters init */
	db->pause.rx_pause = true;
	db->pause.tx_pause = true;
	db->pause.autoneg = AUTONEG_DISABLE;

	if (db->phydev->autoneg)
		db->pause.autoneg = AUTONEG_ENABLE;

	ret = dm9051_all_start(db);
	if (ret) {
		phy_stop(db->phydev);
		free_irq(spi->irq, db);
		return ret;
	}

	netif_wake_queue(ndev);

	return 0;
}

/* Close network device
 * Called to close down a network device which has been active. Cancel any
 * work, shutdown the RX and TX process and then place the chip into a low
 * power state while it is not being used
 */
static int dm9051_stop(struct net_device *ndev)
{
	struct board_info *db = to_dm9051_board(ndev);
	int ret;

	ret = dm9051_all_stop(db);
	if (ret)
		return ret;

	flush_work(&db->tx_work);
	flush_work(&db->rxctrl_work);

	phy_stop(db->phydev);

	free_irq(db->spidev->irq, db);

	netif_stop_queue(ndev);

	skb_queue_purge(&db->txq);

	return 0;
}

/* event: play a schedule starter in condition
 */
static netdev_tx_t dm9051_start_xmit(struct sk_buff *skb, struct net_device *ndev)
{
	struct board_info *db = to_dm9051_board(ndev);

	skb_queue_tail(&db->txq, skb);
	if (skb_queue_len(&db->txq) > DM9051_TX_QUE_HI_WATER)
		netif_stop_queue(ndev); /* enforce limit queue size */

	schedule_work(&db->tx_work);

	return NETDEV_TX_OK;
}

/* event: play with a schedule starter
 */
static void dm9051_set_rx_mode(struct net_device *ndev)
{
	struct board_info *db = to_dm9051_board(ndev);
	struct dm9051_rxctrl rxctrl;
	struct netdev_hw_addr *ha;
	u8 rcr = RCR_DIS_LONG | RCR_DIS_CRC | RCR_RXEN;
	u32 hash_val;

	memset(&rxctrl, 0, sizeof(rxctrl));

	/* rx control */
	if (ndev->flags & IFF_PROMISC) {
		rcr |= RCR_PRMSC;
		netdev_dbg(ndev, "set_multicast rcr |= RCR_PRMSC, rcr= %02x\n", rcr);
	}

	if (ndev->flags & IFF_ALLMULTI) {
		rcr |= RCR_ALL;
		netdev_dbg(ndev, "set_multicast rcr |= RCR_ALLMULTI, rcr= %02x\n", rcr);
	}

	rxctrl.rcr_all = rcr;

	/* broadcast address */
	rxctrl.hash_table[0] = 0;
	rxctrl.hash_table[1] = 0;
	rxctrl.hash_table[2] = 0;
	rxctrl.hash_table[3] = 0x8000;

	/* the multicast address in Hash Table : 64 bits */
	netdev_for_each_mc_addr(ha, ndev) {
		hash_val = ether_crc_le(ETH_ALEN, ha->addr) & GENMASK(5, 0);
		rxctrl.hash_table[hash_val / 16] |= BIT(0) << (hash_val % 16);
	}

	/* schedule work to do the actual set of the data if needed */

	if (memcmp(&db->rctl, &rxctrl, sizeof(rxctrl))) {
		memcpy(&db->rctl, &rxctrl, sizeof(rxctrl));
		schedule_work(&db->rxctrl_work);
	}
}

/* event: write into the mac registers and eeprom directly
 */
static int dm9051_set_mac_address(struct net_device *ndev, void *p)
{
	struct board_info *db = to_dm9051_board(ndev);
	int ret;

	ret = eth_prepare_mac_addr_change(ndev, p);
	if (ret < 0)
		return ret;

	eth_commit_mac_addr_change(ndev, p);
	return dm9051_set_regs(db, DM9051_PAR, ndev->dev_addr, sizeof(ndev->dev_addr));
}

static const struct net_device_ops dm9051_netdev_ops = {
	.ndo_open = dm9051_open,
	.ndo_stop = dm9051_stop,
	.ndo_start_xmit = dm9051_start_xmit,
	.ndo_set_rx_mode = dm9051_set_rx_mode,
	.ndo_validate_addr = eth_validate_addr,
	.ndo_set_mac_address = dm9051_set_mac_address,
};

static void dm9051_operation_clear(struct board_info *db)
{
	db->bc.status_err_counter = 0;
	db->bc.large_err_counter = 0;
	db->bc.rx_err_counter = 0;
	db->bc.tx_err_counter = 0;
	db->bc.fifo_rst_counter = 0;
}

static int dm9051_mdio_register(struct board_info *db)
{
	struct spi_device *spi = db->spidev;
	int ret;

	db->mdiobus = devm_mdiobus_alloc(&spi->dev);
	if (!db->mdiobus)
		return -ENOMEM;

	db->mdiobus->priv = db;
	db->mdiobus->read = dm9051_mdio_read;
	db->mdiobus->write = dm9051_mdio_write;
	db->mdiobus->name = "dm9051-mdiobus";
	db->mdiobus->phy_mask = (u32)~BIT(1);
	db->mdiobus->parent = &spi->dev;
	snprintf(db->mdiobus->id, MII_BUS_ID_SIZE,
		 "dm9051-%s.%u", dev_name(&spi->dev), spi_get_chipselect(spi, 0));

	ret = devm_mdiobus_register(&spi->dev, db->mdiobus);
	if (ret)
		dev_err(&spi->dev, "Could not register MDIO bus\n");

	return ret;
}

static void dm9051_handle_link_change(struct net_device *ndev)
{
	struct board_info *db = to_dm9051_board(ndev);

	phy_print_status(db->phydev);

	/* only write pause settings to mac. since mac and phy are integrated
	 * together, such as link state, speed and duplex are sync already
	 */
	if (db->phydev->link) {
		if (db->phydev->pause) {
			db->pause.rx_pause = true;
			db->pause.tx_pause = true;
		}
		dm9051_update_fcr(db);
	}
}

/* phy connect as poll mode
 */
static int dm9051_phy_connect(struct board_info *db)
{
	char phy_id[MII_BUS_ID_SIZE + 3];

	snprintf(phy_id, sizeof(phy_id), PHY_ID_FMT,
		 db->mdiobus->id, DM9051_PHY_ADDR);

	db->phydev = phy_connect(db->ndev, phy_id, dm9051_handle_link_change,
				 PHY_INTERFACE_MODE_MII);
	if (IS_ERR(db->phydev))
		return PTR_ERR_OR_ZERO(db->phydev);
	return 0;
}

static int dm9051_probe(struct spi_device *spi)
{
	struct device *dev = &spi->dev;
	struct net_device *ndev;
	struct board_info *db;
	int ret;

	ndev = devm_alloc_etherdev(dev, sizeof(struct board_info));
	if (!ndev)
		return -ENOMEM;

	SET_NETDEV_DEV(ndev, dev);
	dev_set_drvdata(dev, ndev);

	db = netdev_priv(ndev);

	db->msg_enable = 0;
	db->spidev = spi;
	db->ndev = ndev;

	ndev->netdev_ops = &dm9051_netdev_ops;
	ndev->ethtool_ops = &dm9051_ethtool_ops;

	mutex_init(&db->spi_lockm);
	mutex_init(&db->reg_mutex);

	INIT_WORK(&db->rxctrl_work, dm9051_rxctl_delay);
	INIT_WORK(&db->tx_work, dm9051_tx_delay);

	ret = dm9051_map_init(spi, db);
	if (ret)
		return ret;

	ret = dm9051_map_chipid(db);
	if (ret)
		return ret;

	ret = dm9051_map_etherdev_par(ndev, db);
	if (ret < 0)
		return ret;

	ret = dm9051_mdio_register(db);
	if (ret)
		return ret;

	ret = dm9051_phy_connect(db);
	if (ret)
		return ret;

	dm9051_operation_clear(db);
	skb_queue_head_init(&db->txq);

	ret = devm_register_netdev(dev, ndev);
	if (ret) {
		phy_disconnect(db->phydev);
		return dev_err_probe(dev, ret, "device register failed");
	}

	return 0;
}

static void dm9051_drv_remove(struct spi_device *spi)
{
	struct device *dev = &spi->dev;
	struct net_device *ndev = dev_get_drvdata(dev);
	struct board_info *db = to_dm9051_board(ndev);

	phy_disconnect(db->phydev);
}

static const struct of_device_id dm9051_match_table[] = {
	{ .compatible = "davicom,dm9051" },
	{}
};

static const struct spi_device_id dm9051_id_table[] = {
	{ "dm9051", 0 },
	{}
};

static struct spi_driver dm9051_driver = {
	.driver = {
		.name = DRVNAME_9051,
		.of_match_table = dm9051_match_table,
	},
	.probe = dm9051_probe,
	.remove = dm9051_drv_remove,
	.id_table = dm9051_id_table,
};
module_spi_driver(dm9051_driver);

MODULE_AUTHOR("Joseph CHANG <joseph_chang@davicom.com.tw>");
MODULE_DESCRIPTION("Davicom DM9051 network SPI driver");
MODULE_LICENSE("GPL");