net: nuvoton : Add NPCM7xx EMAC driver

NPCM750 provides identical ethernet MAC controllers for WAN/LAN applications.

Signed-off-by: Jim Liu <JJLIU0@nuvoton.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>

3 files changed, 751 insertions, 0 deletions

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 0070ff7..52dc9e4 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -523,6 +523,11 @@ config MT7628_ETH
 	  The MediaTek MT7628 ethernet interface is used on MT7628 and
 	  MT7688 based boards.
 
+config NET_NPCM750
+	bool "Nuvoton NPCM750 Ethernet MAC"
+	help
+	  support NPCM750 EMAC
+
 config NET_OCTEON
 	bool "MIPS Octeon ethernet support"
 	depends on ARCH_OCTEON
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 9536af1..054ec68 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -65,6 +65,7 @@ obj-$(CONFIG_MVMDIO) += mvmdio.o
 obj-$(CONFIG_MVNETA) += mvneta.o
 obj-$(CONFIG_MVPP2) += mvpp2.o
 obj-$(CONFIG_NETCONSOLE) += netconsole.o
+obj-$(CONFIG_NET_NPCM750) += npcm750_eth.o
 obj-$(CONFIG_NET_OCTEON) += octeon/
 obj-$(CONFIG_NET_OCTEONTX) += octeontx/
 obj-$(CONFIG_NET_OCTEONTX2) += octeontx2/
diff --git a/drivers/net/npcm750_eth.c b/drivers/net/npcm750_eth.c
new file mode 100644
index 0000000..409d5cc
--- /dev/null
+++ b/drivers/net/npcm750_eth.c
@@ -0,0 +1,745 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2021 Nuvoton Technology Corp.
+ */
+
+#include <common.h>
+#include <cpu_func.h>
+#include <dm.h>
+#include <errno.h>
+#include <miiphy.h>
+#include <malloc.h>
+#include <net.h>
+#include <regmap.h>
+#include <serial.h>
+#include <syscon.h>
+#include <asm/io.h>
+#include <linux/err.h>
+#include <linux/iopoll.h>
+
+#define MAC_ADDR_SIZE		6
+#define CONFIG_TX_DESCR_NUM	32
+#define CONFIG_RX_DESCR_NUM	32
+
+#define TX_TOTAL_BUFSIZE	\
+		((CONFIG_TX_DESCR_NUM + 1) * PKTSIZE_ALIGN + PKTALIGN)
+#define RX_TOTAL_BUFSIZE	\
+		((CONFIG_RX_DESCR_NUM + 1) * PKTSIZE_ALIGN + PKTALIGN)
+
+#define CONFIG_MDIO_TIMEOUT (3 * CONFIG_SYS_HZ)
+
+struct npcm750_rxbd {
+	unsigned int sl;
+	unsigned int buffer;
+	unsigned int reserved;
+	unsigned int next;
+} __aligned(ARCH_DMA_MINALIGN);
+
+struct npcm750_txbd {
+	unsigned int mode;
+	unsigned int buffer;
+	unsigned int sl;
+	unsigned int next;
+} __aligned(ARCH_DMA_MINALIGN);
+
+struct emc_regs {
+	u32 camcmr;		/* 0x00 */
+	u32 camen;		/* 0x04 */
+	u32 cam0m;		/* 0x08 */
+	u32 cam0l;		/* 0x0c */
+	u32 cam1m;		/* 0x10 */
+	u32 cam1l;		/* 0x14 */
+	u32 cam2m;		/* 0x18 */
+	u32 cam2l;		/* 0x1c */
+	u32 cam3m;		/* 0x20 */
+	u32 cam3l;		/* 0x24 */
+	u32 cam4m;		/* 0x28 */
+	u32 cam4l;		/* 0x2c */
+	u32 cam5m;		/* 0x30 */
+	u32 cam5l;		/* 0x34 */
+	u32 cam6m;		/* 0x38 */
+	u32 cam6l;		/* 0x3c */
+	u32 cam7m;		/* 0x40 */
+	u32 cam7l;		/* 0x44 */
+	u32 cam8m;		/* 0x48 */
+	u32 cam8l;		/* 0x4c */
+	u32 cam9m;		/* 0x50 */
+	u32 cam9l;		/* 0x54 */
+	u32 cam10m;		/* 0x58 */
+	u32 cam10l;		/* 0x5c */
+	u32 cam11m;		/* 0x60 */
+	u32 cam11l;		/* 0x64 */
+	u32 cam12m;		/* 0x68 */
+	u32 cam12l;		/* 0x6c */
+	u32 cam13m;		/* 0x70 */
+	u32 cam13l;		/* 0x74 */
+	u32 cam14m;		/* 0x78 */
+	u32 cam14l;		/* 0x7c */
+	u32 cam15m;		/* 0x80 */
+	u32 cam15l;		/* 0x84 */
+	u32 txdlsa;		/* 0x88 */
+	u32 rxdlsa;		/* 0x8c */
+	u32 mcmdr;		/* 0x90 */
+	u32 miid;		/* 0x94 */
+	u32 miida;		/* 0x98 */
+	u32 fftcr;		/* 0x9c */
+	u32 tsdr;		/* 0xa0 */
+	u32 rsdr;		/* 0xa4 */
+	u32 dmarfc;		/* 0xa8 */
+	u32 mien;		/* 0xac */
+	u32 mista;		/* 0xb0 */
+	u32 mgsta;		/* 0xb4 */
+	u32 mpcnt;		/* 0xb8 */
+	u32 mrpc;		/* 0xbc */
+	u32 mrpcc;		/* 0xc0 */
+	u32 mrepc;		/* 0xc4 */
+	u32 dmarfs;		/* 0xc8 */
+	u32 ctxdsa;		/* 0xcc */
+	u32 ctxbsa;		/* 0xd0 */
+	u32 crxdsa;		/* 0xd4 */
+	u32 crxbsa;		/* 0xd8 */
+};
+
+struct npcm750_eth_dev {
+	struct npcm750_txbd tdesc[CONFIG_TX_DESCR_NUM] __aligned(ARCH_DMA_MINALIGN);
+	struct npcm750_rxbd rdesc[CONFIG_RX_DESCR_NUM] __aligned(ARCH_DMA_MINALIGN);
+	u8 txbuffs[TX_TOTAL_BUFSIZE] __aligned(ARCH_DMA_MINALIGN);
+	u8 rxbuffs[RX_TOTAL_BUFSIZE] __aligned(ARCH_DMA_MINALIGN);
+	struct emc_regs *emc_regs_p;
+	struct phy_device *phydev;
+	struct mii_dev *bus;
+	struct npcm750_txbd *curr_txd;
+	struct npcm750_rxbd *curr_rxd;
+	u32 interface;
+	u32 max_speed;
+	u32 idx;
+	struct regmap *gcr_regmap;
+};
+
+struct npcm750_eth_pdata {
+	struct eth_pdata eth_pdata;
+};
+
+/* mac controller bit */
+#define MCMDR_RXON		BIT(0)
+#define MCMDR_ACP		BIT(3)
+#define MCMDR_SPCRC		BIT(5)
+#define MCMDR_TXON		BIT(8)
+#define MCMDR_NDEF		BIT(9)
+#define MCMDR_FDUP		BIT(18)
+#define MCMDR_ENMDC		BIT(19)
+#define MCMDR_OPMOD		BIT(20)
+#define MCMDR_SWR		BIT(24)
+
+/* cam command regiser */
+#define CAMCMR_AUP		0x01
+#define CAMCMR_AMP		BIT(1)
+#define CAMCMR_ABP		BIT(2)
+#define CAMCMR_CCAM		BIT(3)
+#define CAMCMR_ECMP		BIT(4)
+#define CAM0EN			0x01
+
+/* mac mii controller bit */
+#define MDCON			BIT(19)
+#define PHYAD			BIT(8)
+#define PHYWR			BIT(16)
+#define PHYBUSY			BIT(17)
+#define PHYPRESP		BIT(18)
+#define CAM_ENTRY_SIZE	0x08
+
+/* rx and tx status */
+#define TXDS_TXCP		BIT(19)
+#define RXDS_CRCE		BIT(17)
+#define RXDS_PTLE		BIT(19)
+#define RXDS_RXGD		BIT(20)
+#define RXDS_ALIE		BIT(21)
+#define RXDS_RP			BIT(22)
+
+/* mac interrupt status*/
+#define MISTA_RXINTR		BIT(0)
+#define MISTA_CRCE		BIT(1)
+#define MISTA_RXOV		BIT(2)
+#define MISTA_PTLE		BIT(3)
+#define MISTA_RXGD		BIT(4)
+#define MISTA_ALIE		BIT(5)
+#define MISTA_RP		BIT(6)
+#define MISTA_MMP		BIT(7)
+#define MISTA_DFOI		BIT(8)
+#define MISTA_DENI		BIT(9)
+#define MISTA_RDU		BIT(10)
+#define MISTA_RXBERR		BIT(11)
+#define MISTA_CFR		BIT(14)
+#define MISTA_TXINTR		BIT(16)
+#define MISTA_TXEMP		BIT(17)
+#define MISTA_TXCP		BIT(18)
+#define MISTA_EXDEF		BIT(19)
+#define MISTA_NCS		BIT(20)
+#define MISTA_TXABT		BIT(21)
+#define MISTA_LC		BIT(22)
+#define MISTA_TDU		BIT(23)
+#define MISTA_TXBERR		BIT(24)
+
+#define ENSTART			0x01
+#define ENRXINTR		BIT(0)
+#define ENCRCE			BIT(1)
+#define EMRXOV			BIT(2)
+#define ENPTLE			BIT(3)
+#define ENRXGD			BIT(4)
+#define ENALIE			BIT(5)
+#define ENRP			BIT(6)
+#define ENMMP			BIT(7)
+#define ENDFO			BIT(8)
+#define ENDENI			BIT(9)
+#define ENRDU			BIT(10)
+#define ENRXBERR		BIT(11)
+#define ENCFR			BIT(14)
+#define ENTXINTR		BIT(16)
+#define ENTXEMP			BIT(17)
+#define ENTXCP			BIT(18)
+#define ENTXDEF			BIT(19)
+#define ENNCS			BIT(20)
+#define ENTXABT			BIT(21)
+#define ENLC			BIT(22)
+#define ENTDU			BIT(23)
+#define ENTXBERR		BIT(24)
+
+#define RX_STAT_RBC     0xffff
+#define RX_STAT_RXINTR  BIT(16)
+#define RX_STAT_CRCE    BIT(17)
+#define RX_STAT_PTLE    BIT(19)
+#define RX_STAT_RXGD    BIT(20)
+#define RX_STAT_ALIE    BIT(21)
+#define RX_STAT_RP      BIT(22)
+#define RX_STAT_OWNER   (BIT(30) | BIT(31))
+
+#define TX_STAT_TBC     0xffff
+#define TX_STAT_TXINTR  BIT(16)
+#define TX_STAT_DEF     BIT(17)
+#define TX_STAT_TXCP    BIT(19)
+#define TX_STAT_EXDEF   BIT(20)
+#define TX_STAT_NCS     BIT(21)
+#define TX_STAT_TXBT    BIT(22)
+#define TX_STAT_LC      BIT(23)
+#define TX_STAT_TXHA    BIT(24)
+#define TX_STAT_PAU     BIT(25)
+#define TX_STAT_SQE     BIT(26)
+
+/* rx and tx owner bit */
+#define RX_OWEN_DMA		BIT(31)
+#define RX_OWEN_CPU		0x00       //bit 30 & bit 31
+#define TX_OWEN_DMA		BIT(31)
+#define TX_OWEN_CPU		(~(BIT(31)))
+
+/* tx frame desc controller bit */
+#define MACTXINTEN		0x04
+#define CRCMODE			0x02
+#define PADDINGMODE		0x01
+
+/* fftcr controller bit */
+#define RXTHD			0x03
+#define TXTHD			(BIT(8) | BIT(9))
+#define BLENGTH			BIT(21)
+
+/* global setting for driver */
+#define RX_DESC_SIZE	128
+#define TX_DESC_SIZE	64
+#define MAX_RBUFF_SZ	0x600
+#define MAX_TBUFF_SZ	0x600
+#define TX_TIMEOUT	50
+#define DELAY		1000
+#define CAM0		0x0
+#define RX_POLL_SIZE	(RX_DESC_SIZE / 2)
+#define MII_TIMEOUT	100
+#define GCR_INTCR	0x3c
+#define INTCR_R1EN	BIT(5)
+
+enum MIIDA_MDCCR_T {
+	MIIDA_MDCCR_4       = 0x00,
+	MIIDA_MDCCR_6       = 0x01,
+	MIIDA_MDCCR_8       = 0x02,
+	MIIDA_MDCCR_12      = 0x03,
+	MIIDA_MDCCR_16      = 0x04,
+	MIIDA_MDCCR_20      = 0x05,
+	MIIDA_MDCCR_24      = 0x06,
+	MIIDA_MDCCR_28      = 0x07,
+	MIIDA_MDCCR_30      = 0x08,
+	MIIDA_MDCCR_32      = 0x09,
+	MIIDA_MDCCR_36      = 0x0A,
+	MIIDA_MDCCR_40      = 0x0B,
+	MIIDA_MDCCR_44      = 0x0C,
+	MIIDA_MDCCR_48      = 0x0D,
+	MIIDA_MDCCR_54      = 0x0E,
+	MIIDA_MDCCR_60      = 0x0F,
+};
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static int npcm750_mdio_read(struct mii_dev *bus, int addr, int devad, int regs)
+{
+	struct npcm750_eth_dev *priv = (struct npcm750_eth_dev *)bus->priv;
+	struct emc_regs *reg = priv->emc_regs_p;
+	u32 start, val;
+	int timeout = CONFIG_MDIO_TIMEOUT;
+
+	val = (addr << 0x08) | regs | PHYBUSY | (MIIDA_MDCCR_60 << 20);
+	writel(val, &reg->miida);
+
+	start = get_timer(0);
+	while (get_timer(start) < timeout) {
+		if (!(readl(&reg->miida) & PHYBUSY)) {
+			val = readl(&reg->miid);
+			return val;
+		}
+		udelay(10);
+	};
+	return -ETIMEDOUT;
+}
+
+static int npcm750_mdio_write(struct mii_dev *bus, int addr, int devad, int regs,
+			      u16 val)
+{
+	struct npcm750_eth_dev *priv = (struct npcm750_eth_dev *)bus->priv;
+	struct emc_regs *reg = priv->emc_regs_p;
+	ulong start;
+	int ret = -ETIMEDOUT, timeout = CONFIG_MDIO_TIMEOUT;
+
+	writel(val, &reg->miid);
+	writel((addr << 0x08) | regs | PHYBUSY | PHYWR | (MIIDA_MDCCR_60 << 20), &reg->miida);
+
+	start = get_timer(0);
+	while (get_timer(start) < timeout) {
+		if (!(readl(&reg->miida) & PHYBUSY)) {
+			ret = 0;
+			break;
+		}
+		udelay(10);
+	};
+	return ret;
+}
+
+static int npcm750_mdio_reset(struct mii_dev *bus)
+{
+	return 0;
+}
+
+static int npcm750_mdio_init(const char *name, struct npcm750_eth_dev *priv)
+{
+	struct emc_regs *reg = priv->emc_regs_p;
+	struct mii_dev *bus = mdio_alloc();
+
+	if (!bus) {
+		printf("Failed to allocate MDIO bus\n");
+		return -ENOMEM;
+	}
+
+	bus->read = npcm750_mdio_read;
+	bus->write = npcm750_mdio_write;
+	snprintf(bus->name, sizeof(bus->name), "%s", name);
+	bus->reset = npcm750_mdio_reset;
+
+	bus->priv = (void *)priv;
+
+	writel(readl(&reg->mcmdr) | MCMDR_ENMDC, &reg->mcmdr);
+	return mdio_register(bus);
+}
+
+static void npcm750_tx_descs_init(struct npcm750_eth_dev *priv)
+{
+	struct emc_regs *reg = priv->emc_regs_p;
+	struct npcm750_txbd *desc_table_p = &priv->tdesc[0];
+	struct npcm750_txbd *desc_p;
+	u8 *txbuffs = &priv->txbuffs[0];
+	u32 idx;
+
+	writel((u32)desc_table_p, &reg->txdlsa);
+	priv->curr_txd = desc_table_p;
+
+	for (idx = 0; idx < CONFIG_TX_DESCR_NUM; idx++) {
+		desc_p = &desc_table_p[idx];
+		desc_p->buffer = (u32)&txbuffs[idx * PKTSIZE_ALIGN];
+		desc_p->sl = 0;
+		desc_p->mode = 0;
+		desc_p->mode = TX_OWEN_CPU | PADDINGMODE | CRCMODE | MACTXINTEN;
+		if (idx < (CONFIG_TX_DESCR_NUM - 1))
+			desc_p->next = (u32)&desc_table_p[idx + 1];
+		else
+			desc_p->next = (u32)&priv->tdesc[0];
+	}
+	flush_dcache_range((ulong)&desc_table_p[0],
+			   (ulong)&desc_table_p[CONFIG_TX_DESCR_NUM]);
+}
+
+static void npcm750_rx_descs_init(struct npcm750_eth_dev *priv)
+{
+	struct emc_regs *reg = priv->emc_regs_p;
+	struct npcm750_rxbd *desc_table_p = &priv->rdesc[0];
+	struct npcm750_rxbd *desc_p;
+	u8 *rxbuffs = &priv->rxbuffs[0];
+	u32 idx;
+
+	flush_dcache_range((ulong)priv->rxbuffs[0],
+			   (ulong)priv->rxbuffs[CONFIG_RX_DESCR_NUM]);
+
+	writel((u32)desc_table_p, &reg->rxdlsa);
+	priv->curr_rxd = desc_table_p;
+
+	for (idx = 0; idx < CONFIG_RX_DESCR_NUM; idx++) {
+		desc_p = &desc_table_p[idx];
+		desc_p->sl = RX_OWEN_DMA;
+		desc_p->buffer = (u32)&rxbuffs[idx * PKTSIZE_ALIGN];
+		if (idx < (CONFIG_RX_DESCR_NUM - 1))
+			desc_p->next = (u32)&desc_table_p[idx + 1];
+		else
+			desc_p->next = (u32)&priv->rdesc[0];
+	}
+	flush_dcache_range((ulong)&desc_table_p[0],
+			   (ulong)&desc_table_p[CONFIG_RX_DESCR_NUM]);
+}
+
+static void npcm750_set_fifo_threshold(struct npcm750_eth_dev *priv)
+{
+	struct emc_regs *reg = priv->emc_regs_p;
+	unsigned int val;
+
+	val = RXTHD | TXTHD | BLENGTH;
+	writel(val, &reg->fftcr);
+}
+
+static void npcm750_set_global_maccmd(struct npcm750_eth_dev *priv)
+{
+	struct emc_regs *reg = priv->emc_regs_p;
+	unsigned int val;
+
+	val = readl(&reg->mcmdr);
+	val |= MCMDR_SPCRC | MCMDR_ENMDC | MCMDR_ACP | MCMDR_NDEF;
+	writel(val, &reg->mcmdr);
+}
+
+static void npcm750_set_cam(struct npcm750_eth_dev *priv,
+			    unsigned int x, unsigned char *pval)
+{
+	struct emc_regs *reg = priv->emc_regs_p;
+	unsigned int msw, lsw;
+
+	msw = (pval[0] << 24) | (pval[1] << 16) | (pval[2] << 8) | pval[3];
+	lsw = (pval[4] << 24) | (pval[5] << 16);
+
+	writel(lsw, &reg->cam0l + x * CAM_ENTRY_SIZE);
+	writel(msw, &reg->cam0m + x * CAM_ENTRY_SIZE);
+	writel(readl(&reg->camen) | CAM0EN, &reg->camen);
+	writel(CAMCMR_ECMP | CAMCMR_ABP | CAMCMR_AUP, &reg->camcmr);
+}
+
+static void npcm750_adjust_link(struct emc_regs *reg,
+				struct phy_device *phydev)
+{
+	u32 val = readl(&reg->mcmdr);
+
+	if (!phydev->link) {
+		printf("%s: No link.\n", phydev->dev->name);
+		return;
+	}
+
+	if (phydev->speed == 100)
+		val |= MCMDR_OPMOD;
+	else
+		val &= ~MCMDR_OPMOD;
+
+	if (phydev->duplex)
+		val |= MCMDR_FDUP;
+	else
+		val &= ~MCMDR_FDUP;
+
+	writel(val, &reg->mcmdr);
+
+	debug("Speed: %d, %s duplex%s\n", phydev->speed,
+	      (phydev->duplex) ? "full" : "half",
+	      (phydev->port == PORT_FIBRE) ? ", fiber mode" : "");
+}
+
+static int npcm750_phy_init(struct npcm750_eth_dev *priv, void *dev)
+{
+	struct phy_device *phydev;
+	int ret;
+	u32 address = 0x0;
+
+	phydev = phy_connect(priv->bus, address, dev, priv->interface);
+	if (!phydev)
+		return -ENODEV;
+
+	if (priv->max_speed) {
+		ret = phy_set_supported(phydev, priv->max_speed);
+		if (ret)
+			return ret;
+	}
+	phydev->advertising = phydev->supported;
+
+	priv->phydev = phydev;
+	phy_config(phydev);
+	return 0;
+}
+
+static int npcm750_eth_start(struct udevice *dev)
+{
+	struct eth_pdata *pdata = dev_get_plat(dev);
+	struct npcm750_eth_dev *priv = dev_get_priv(dev);
+	struct emc_regs *reg = priv->emc_regs_p;
+	u8 *enetaddr = pdata->enetaddr;
+	int ret;
+
+	writel(readl(&reg->mcmdr) & ~MCMDR_TXON  & ~MCMDR_RXON, &reg->mcmdr);
+
+	writel(readl(&reg->mcmdr) | MCMDR_SWR, &reg->mcmdr);
+	do {
+		ret = readl(&reg->mcmdr);
+	} while (ret & MCMDR_SWR);
+
+	npcm750_rx_descs_init(priv);
+	npcm750_tx_descs_init(priv);
+
+	npcm750_set_cam(priv, priv->idx, enetaddr);
+	npcm750_set_global_maccmd(priv);
+	npcm750_set_fifo_threshold(priv);
+
+	/* Start up the PHY */
+	ret = phy_startup(priv->phydev);
+	if (ret) {
+		printf("Could not initialize PHY\n");
+		return ret;
+	}
+
+	npcm750_adjust_link(reg, priv->phydev);
+	writel(readl(&reg->mcmdr) | MCMDR_TXON | MCMDR_RXON, &reg->mcmdr);
+
+	return 0;
+}
+
+static int npcm750_eth_send(struct udevice *dev, void *packet, int length)
+{
+	struct npcm750_eth_dev *priv = dev_get_priv(dev);
+	struct emc_regs *reg = priv->emc_regs_p;
+	struct npcm750_txbd *desc_p;
+	struct npcm750_txbd *next_desc_p;
+
+	desc_p = priv->curr_txd;
+
+	invalidate_dcache_range((ulong)desc_p, (ulong)(desc_p + 1));
+	/* Check if the descriptor is owned by CPU */
+	if (desc_p->mode & TX_OWEN_DMA) {
+		next_desc_p = (struct npcm750_txbd *)desc_p->next;
+
+		while ((next_desc_p != desc_p) && (next_desc_p->mode & TX_OWEN_DMA))
+			next_desc_p = (struct npcm750_txbd *)next_desc_p->next;
+
+		if (next_desc_p == desc_p) {
+			struct emc_regs *reg = priv->emc_regs_p;
+
+			writel(0, &reg->tsdr);
+			serial_printf("TX: overflow and exit\n");
+			return -EPERM;
+		}
+
+		desc_p = next_desc_p;
+	}
+
+	memcpy((void *)desc_p->buffer, packet, length);
+	flush_dcache_range((ulong)desc_p->buffer,
+			   (ulong)desc_p->buffer + roundup(length, ARCH_DMA_MINALIGN));
+	desc_p->sl = 0;
+	desc_p->sl = length & TX_STAT_TBC;
+	desc_p->mode = TX_OWEN_DMA | PADDINGMODE | CRCMODE;
+	flush_dcache_range((ulong)desc_p, (ulong)(desc_p + 1));
+
+	if (!(readl(&reg->mcmdr) & MCMDR_TXON))
+		writel(readl(&reg->mcmdr) | MCMDR_TXON, &reg->mcmdr);
+	priv->curr_txd = (struct npcm750_txbd *)priv->curr_txd->next;
+
+	writel(0, &reg->tsdr);
+	return 0;
+}
+
+static int npcm750_eth_recv(struct udevice *dev, int flags, uchar **packetp)
+{
+	struct npcm750_eth_dev *priv = dev_get_priv(dev);
+	struct npcm750_rxbd *desc_p;
+	struct npcm750_rxbd *next_desc_p;
+	int length = -1;
+
+	desc_p = priv->curr_rxd;
+	invalidate_dcache_range((ulong)desc_p, (ulong)(desc_p + 1));
+
+	if ((desc_p->sl & RX_STAT_OWNER) == RX_OWEN_DMA) {
+		next_desc_p = (struct npcm750_rxbd *)desc_p->next;
+		while ((next_desc_p != desc_p) &&
+		       ((next_desc_p->sl & RX_STAT_OWNER) == RX_OWEN_CPU)) {
+			next_desc_p = (struct npcm750_rxbd *)next_desc_p->next;
+		}
+
+		if (next_desc_p == desc_p) {
+			struct emc_regs *reg = priv->emc_regs_p;
+
+			writel(0, &reg->rsdr);
+			serial_printf("RX: overflow and exit\n");
+			return -EPERM;
+		}
+		desc_p = next_desc_p;
+	}
+
+	/* Check if the descriptor is owned by CPU */
+	if ((desc_p->sl & RX_STAT_OWNER) == RX_OWEN_CPU) {
+		if (desc_p->sl & RX_STAT_RXGD) {
+			length = desc_p->sl & RX_STAT_RBC;
+			invalidate_dcache_range((ulong)desc_p->buffer,
+						(ulong)(desc_p->buffer + roundup(length,
+						ARCH_DMA_MINALIGN)));
+			*packetp = (u8 *)(u32)desc_p->buffer;
+			priv->curr_rxd = desc_p;
+		}
+	}
+	return length;
+}
+
+static int npcm750_eth_free_pkt(struct udevice *dev, uchar *packet, int length)
+{
+	struct npcm750_eth_dev *priv = dev_get_priv(dev);
+	struct emc_regs *reg = priv->emc_regs_p;
+	struct npcm750_rxbd *desc_p = priv->curr_rxd;
+
+	/*
+	 * Make the current descriptor valid again and go to
+	 * the next one
+	 */
+	desc_p->sl |= RX_OWEN_DMA;
+	flush_dcache_range((ulong)desc_p, (ulong)(desc_p + 1));
+	priv->curr_rxd = (struct npcm750_rxbd *)priv->curr_rxd->next;
+	writel(0, &reg->rsdr);
+
+	return 0;
+}
+
+static void npcm750_eth_stop(struct udevice *dev)
+{
+	struct npcm750_eth_dev *priv = dev_get_priv(dev);
+	struct emc_regs *reg = priv->emc_regs_p;
+
+	writel(readl(&reg->mcmdr) & ~MCMDR_TXON, &reg->mcmdr);
+	writel(readl(&reg->mcmdr) & ~MCMDR_RXON, &reg->mcmdr);
+	priv->curr_txd = (struct npcm750_txbd *)readl(&reg->txdlsa);
+	priv->curr_rxd = (struct npcm750_rxbd *)readl(&reg->rxdlsa);
+	phy_shutdown(priv->phydev);
+}
+
+static int npcm750_eth_write_hwaddr(struct udevice *dev)
+{
+	struct eth_pdata *pdata = dev_get_plat(dev);
+	struct npcm750_eth_dev *priv = dev_get_priv(dev);
+
+	npcm750_set_cam(priv, CAM0, pdata->enetaddr);
+	return 0;
+}
+
+static int npcm750_eth_bind(struct udevice *dev)
+{
+	return 0;
+}
+
+static int npcm750_eth_probe(struct udevice *dev)
+{
+	struct eth_pdata *pdata = dev_get_plat(dev);
+	struct npcm750_eth_dev *priv = dev_get_priv(dev);
+	u32 iobase = pdata->iobase;
+	int ret;
+
+	memset(priv, 0, sizeof(struct npcm750_eth_dev));
+	ret = dev_read_u32(dev, "id", &priv->idx);
+	if (ret) {
+		printf("failed to get id\n");
+		return -EINVAL;
+	}
+
+	priv->gcr_regmap = syscon_regmap_lookup_by_phandle(dev, "syscon-gcr");
+	if (IS_ERR(priv->gcr_regmap))
+		return -EINVAL;
+
+	priv->emc_regs_p = (struct emc_regs *)iobase;
+	priv->interface = pdata->phy_interface;
+	priv->max_speed = pdata->max_speed;
+
+	if (priv->idx == 0) {
+		/* Enable RMII for EMC1 module */
+		regmap_update_bits(priv->gcr_regmap, GCR_INTCR, INTCR_R1EN, INTCR_R1EN);
+	}
+
+	npcm750_mdio_init(dev->name, priv);
+	priv->bus = miiphy_get_dev_by_name(dev->name);
+
+	ret = npcm750_phy_init(priv, dev);
+
+	return ret;
+}
+
+static int npcm750_eth_remove(struct udevice *dev)
+{
+	struct npcm750_eth_dev *priv = dev_get_priv(dev);
+
+	free(priv->phydev);
+	mdio_unregister(priv->bus);
+	mdio_free(priv->bus);
+
+	return 0;
+}
+
+static const struct eth_ops npcm750_eth_ops = {
+	.start			= npcm750_eth_start,
+	.send			= npcm750_eth_send,
+	.recv			= npcm750_eth_recv,
+	.free_pkt		= npcm750_eth_free_pkt,
+	.stop			= npcm750_eth_stop,
+	.write_hwaddr	= npcm750_eth_write_hwaddr,
+};
+
+static int npcm750_eth_ofdata_to_platdata(struct udevice *dev)
+{
+	struct npcm750_eth_pdata *npcm750_pdata = dev_get_plat(dev);
+	struct eth_pdata *pdata = &npcm750_pdata->eth_pdata;
+	const char *phy_mode;
+	const fdt32_t *cell;
+	int ret = 0;
+
+	pdata->iobase = (phys_addr_t)dev_read_addr_ptr(dev);
+
+	pdata->phy_interface = -1;
+	phy_mode = fdt_getprop(gd->fdt_blob, dev_of_offset(dev), "phy-mode", NULL);
+	if (phy_mode)
+		pdata->phy_interface = phy_get_interface_by_name(phy_mode);
+	if (pdata->phy_interface == -1) {
+		printf("%s: Invalid PHY interface '%s'\n", __func__, phy_mode);
+		return -EINVAL;
+	}
+
+	pdata->max_speed = 0;
+	cell = fdt_getprop(gd->fdt_blob, dev_of_offset(dev), "max-speed", NULL);
+	if (cell)
+		pdata->max_speed = fdt32_to_cpu(*cell);
+
+	return ret;
+}
+
+static const struct udevice_id npcm750_eth_ids[] = {
+	{ .compatible = "nuvoton,npcm750-emc" },
+	{ }
+};
+
+U_BOOT_DRIVER(eth_npcm750) = {
+	.name	= "eth_npcm750",
+	.id	= UCLASS_ETH,
+	.of_match = npcm750_eth_ids,
+	.of_to_plat = npcm750_eth_ofdata_to_platdata,
+	.bind	= npcm750_eth_bind,
+	.probe	= npcm750_eth_probe,
+	.remove	= npcm750_eth_remove,
+	.ops	= &npcm750_eth_ops,
+	.priv_auto = sizeof(struct npcm750_eth_dev),
+	.plat_auto = sizeof(struct npcm750_eth_pdata),
+	.flags = DM_FLAG_ALLOC_PRIV_DMA,
+};