[U-Boot] [PATCH v2] net: Add MT76xx ethernet driver

[Stefan Roese <sr@denx.de>]

This patch adds ethernet support for the Mediatek MT76xx SoC, including
a minimum setup of the integrated switch. This driver is loosly based on
the driver version included in this MediaTek github repository:

https://github.com/MediaTek-Labs/linkit-smart-uboot.git

Tested on the MT7688 LinkIt smart-gateway and on the
Gardena-smart-gateway.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Cc: Joe Hershberger <joe.hershberger@ni.com>
---
v2:
- Use wait_for_bit_le32() in more places
- Use syscon / regmap to access the system-controller registers
  needed in this driver instead of finding and mapping this
  area

 drivers/net/Kconfig      |   7 +
 drivers/net/Makefile     |   1 +
 drivers/net/mt76xx-eth.c | 638 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 646 insertions(+)
 create mode 100644 drivers/net/mt76xx-eth.c

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 5441da47d1..ed73f21a59 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -227,6 +227,13 @@ config MACB_ZYNQ
 	  The Cadence MACB ethernet interface was used on Zynq platform.
 	  Say Y to enable support for the MACB/GEM in Zynq chip.
 
+config MT76XX_ETH
+	bool "MediaTek MT76xx Ethernet Interface"
+	depends on ARCH_MT7620
+	help
+	  The MediaTek MT76xx ethernet interface is used on MT7688
+	  based boards.
+
 config PCH_GBE
 	bool "Intel Platform Controller Hub EG20T GMAC driver"
 	depends on DM_ETH && DM_PCI
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 48a2878071..05189514b7 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_LPC32XX_ETH) += lpc32xx_eth.o
 obj-$(CONFIG_MACB) += macb.o
 obj-$(CONFIG_MCFFEC) += mcffec.o mcfmii.o
 obj-$(CONFIG_MPC8XX_FEC) += mpc8xx_fec.o
+obj-$(CONFIG_MT76XX_ETH) += mt76xx-eth.o
 obj-$(CONFIG_MVGBE) += mvgbe.o
 obj-$(CONFIG_MVNETA) += mvneta.o
 obj-$(CONFIG_MVPP2) += mvpp2.o
diff --git a/drivers/net/mt76xx-eth.c b/drivers/net/mt76xx-eth.c
new file mode 100644
index 0000000000..a623a475af
--- /dev/null
+++ b/drivers/net/mt76xx-eth.c
@@ -0,0 +1,638 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * MediaTek ethernet IP driver for U-Boot
+ *
+ * Copyright (C) 2018 Stefan Roese <sr@denx.de>
+ *
+ * This code is mostly based on the code extracted from this MediaTek
+ * github repository:
+ *
+ * https://github.com/MediaTek-Labs/linkit-smart-uboot.git
+ *
+ * I was not able to find a specific license or other developers
+ * copyrights here, so I can't add them here.
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <malloc.h>
+#include <miiphy.h>
+#include <net.h>
+#include <regmap.h>
+#include <syscon.h>
+#include <wait_bit.h>
+#include <asm/io.h>
+#include <linux/err.h>
+
+/* System controller register */
+#define MT76XX_RSTCTRL_REG	0x34
+#define RSTCTRL_EPHY_RST	BIT(24)
+
+#define MT76XX_AGPIO_CFG_REG	0x3c
+#define MT7628_EPHY_GPIO_AIO_EN	GENMASK(20, 17)
+#define MT7628_EPHY_P0_DIS	BIT(16)
+
+#define MT76XX_GPIO2_MODE_REG	0x64
+
+/* Ethernet frame engine register */
+#define PDMA_RELATED		0x0800
+
+#define TX_BASE_PTR0		(PDMA_RELATED + 0x000)
+#define TX_MAX_CNT0		(PDMA_RELATED + 0x004)
+#define TX_CTX_IDX0		(PDMA_RELATED + 0x008)
+#define TX_DTX_IDX0		(PDMA_RELATED + 0x00c)
+
+#define RX_BASE_PTR0		(PDMA_RELATED + 0x100)
+#define RX_MAX_CNT0		(PDMA_RELATED + 0x104)
+#define RX_CALC_IDX0		(PDMA_RELATED + 0x108)
+
+#define PDMA_GLO_CFG		(PDMA_RELATED + 0x204)
+#define PDMA_RST_IDX		(PDMA_RELATED + 0x208)
+#define DLY_INT_CFG		(PDMA_RELATED + 0x20c)
+
+#define SDM_RELATED		0x0c00
+
+#define SDM_MAC_ADRL		(SDM_RELATED + 0x0c)	/* MAC address LSB */
+#define SDM_MAC_ADRH		(SDM_RELATED + 0x10)	/* MAC Address MSB */
+
+#define RST_DTX_IDX0		BIT(0)
+#define RST_DRX_IDX0		BIT(16)
+
+#define TX_DMA_EN		BIT(0)
+#define TX_DMA_BUSY		BIT(1)
+#define RX_DMA_EN		BIT(2)
+#define RX_DMA_BUSY		BIT(3)
+#define TX_WB_DDONE		BIT(6)
+
+/* Ethernet switch register */
+#define MT76XX_SWITCH_FCT0	0x0008
+#define MT76XX_SWITCH_PFC1	0x0014
+#define MT76XX_SWITCH_FPA	0x0084
+#define MT76XX_SWITCH_SOCPC	0x008c
+#define MT76XX_SWITCH_POC0	0x0090
+#define MT76XX_SWITCH_POC2	0x0098
+#define MT76XX_SWITCH_SGC	0x009c
+#define MT76XX_SWITCH_PCR0	0x00c0
+#define MT76XX_SWITCH_PCR1	0x00c4
+#define MT76XX_SWITCH_FPA1	0x00c8
+#define MT76XX_SWITCH_FCT2	0x00cc
+#define MT76XX_SWITCH_SGC2	0x00e4
+#define MT76XX_SWITCH_BMU_CTRL	0x0110
+
+/* rxd2 */
+#define RX_DMA_DONE		BIT(31)
+#define RX_DMA_LSO		BIT(30)
+#define RX_DMA_PLEN0(_x)	(((_x) & 0x3fff) << 16)
+#define RX_DMA_GET_PLEN0(_x)	(((_x) >> 16) & 0x3fff)
+#define RX_DMA_TAG		BIT(15)
+/* rxd3 */
+#define RX_DMA_TPID(_x)		(((_x) >> 16) & 0xffff)
+#define RX_DMA_VID(_x)		((_x) & 0xffff)
+/* rxd4 */
+#define RX_DMA_L4VALID		BIT(30)
+
+struct fe_rx_dma {
+	unsigned int rxd1;
+	unsigned int rxd2;
+	unsigned int rxd3;
+	unsigned int rxd4;
+} __packed __aligned(4);
+
+#define TX_DMA_BUF_LEN		0x3fff
+#define TX_DMA_PLEN0_MASK	(TX_DMA_BUF_LEN << 16)
+#define TX_DMA_PLEN0(_x)	(((_x) & TX_DMA_BUF_LEN) << 16)
+#define TX_DMA_PLEN1(_x)	((_x) & TX_DMA_BUF_LEN)
+#define TX_DMA_GET_PLEN0(_x)    (((_x) >> 16) & TX_DMA_BUF_LEN)
+#define TX_DMA_GET_PLEN1(_x)    ((_x) & TX_DMA_BUF_LEN)
+#define TX_DMA_LS1		BIT(14)
+#define TX_DMA_LS0		BIT(30)
+#define TX_DMA_DONE		BIT(31)
+
+#define TX_DMA_INS_VLAN_MT7621	BIT(16)
+#define TX_DMA_INS_VLAN		BIT(7)
+#define TX_DMA_INS_PPPOE	BIT(12)
+#define TX_DMA_QN(_x)		((_x) << 16)
+#define TX_DMA_PN(_x)		((_x) << 24)
+#define TX_DMA_QN_MASK		TX_DMA_QN(0x7)
+#define TX_DMA_PN_MASK		TX_DMA_PN(0x7)
+#define TX_DMA_UDF		BIT(20)
+#define TX_DMA_CHKSUM		(0x7 << 29)
+#define TX_DMA_TSO		BIT(28)
+
+struct fe_tx_dma {
+	unsigned int txd1;
+	unsigned int txd2;
+	unsigned int txd3;
+	unsigned int txd4;
+} __packed __aligned(4);
+
+#define NUM_RX_DESC		256
+#define NUM_TX_DESC		4
+
+#define PADDING_LENGTH		60
+
+#define MTK_QDMA_PAGE_SIZE	2048
+
+#define CONFIG_MDIO_TIMEOUT	100
+#define CONFIG_DMA_STOP_TIMEOUT	100
+#define CONFIG_TX_DMA_TIMEOUT	100
+
+#define LINK_DELAY_TIME		500		/* 500 ms */
+#define LINK_TIMEOUT		10000		/* 10 seconds */
+
+struct mt76xx_eth_dev {
+	void __iomem *base;		/* frame engine base address */
+	void __iomem *eth_sw_base;	/* switch base address */
+	struct regmap *sysctrl_regmap;	/* system-controller reg-map */
+
+	struct mii_dev *bus;
+
+	struct fe_tx_dma *tx_ring;
+	struct fe_rx_dma *rx_ring;
+
+	u8 *rx_buf[NUM_RX_DESC];
+
+	/* Point to the next RXD DMA wants to use in RXD Ring0 */
+	int rx_dma_idx;
+	/* Point to the next TXD in TXD Ring0 CPU wants to use */
+	int tx_dma_idx;
+};
+
+static int mdio_wait_read(struct mt76xx_eth_dev *priv, u32 mask, bool mask_set)
+{
+	void __iomem *base = priv->eth_sw_base;
+	int ret;
+
+	ret = wait_for_bit_le32(base + MT76XX_SWITCH_PCR1, mask, mask_set,
+				CONFIG_MDIO_TIMEOUT, false);
+	if (ret) {
+		printf("MDIO operation timeout!\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int mii_mgr_read(struct mt76xx_eth_dev *priv,
+			u32 phy_addr, u32 phy_register, u32 *read_data)
+{
+	void __iomem *base = priv->eth_sw_base;
+	u32 status = 0;
+	u32 ret;
+
+	*read_data = 0xffff;
+	/* Make sure previous read operation is complete */
+	ret = mdio_wait_read(priv, BIT(1), false);
+	if (ret)
+		return ret;
+
+	writel(BIT(14) | (phy_register << 8) | phy_addr,
+	       base + MT76XX_SWITCH_PCR0);
+
+	/* Make sure previous read operation is complete */
+	ret = mdio_wait_read(priv, BIT(1), true);
+	if (ret)
+		return ret;
+
+	status = readl(base + MT76XX_SWITCH_PCR1);
+	*read_data = (u32)(status >> 16);
+
+	return 0;
+}
+
+static int mii_mgr_write(struct mt76xx_eth_dev *priv,
+			 u32 phy_addr, u32 phy_register, u32 write_data)
+{
+	void __iomem *base = priv->eth_sw_base;
+	u32 data;
+	int ret;
+
+	/* Make sure previous write operation is complete */
+	ret = mdio_wait_read(priv, BIT(0), false);
+	if (ret)
+		return ret;
+
+	data = (write_data & 0xffff) << 16;
+	data |= (phy_register << 8) | phy_addr;
+	data |= BIT(13);
+	writel(data, base + MT76XX_SWITCH_PCR0);
+
+	return mdio_wait_read(priv, BIT(0), true);
+}
+
+static int mt76xx_mdio_read(struct mii_dev *bus, int addr, int devad, int reg)
+{
+	u32 val;
+	int ret;
+
+	ret = mii_mgr_read(bus->priv, addr, reg, &val);
+	if (ret)
+		return ret;
+
+	return val;
+}
+
+static int mt76xx_mdio_write(struct mii_dev *bus, int addr, int devad, int reg,
+			     u16 value)
+{
+	return mii_mgr_write(bus->priv, addr, reg, value);
+}
+
+static void mt7628_ephy_init(struct mt76xx_eth_dev *priv)
+{
+	int i;
+
+	mii_mgr_write(priv, 0, 31, 0x2000);	/* change G2 page */
+	mii_mgr_write(priv, 0, 26, 0x0000);
+
+	for (i = 0; i < 5; i++) {
+		mii_mgr_write(priv, i, 31, 0x8000);	/* change L0 page */
+		mii_mgr_write(priv, i,  0, 0x3100);
+
+		/* EEE disable */
+		mii_mgr_write(priv, i, 30, 0xa000);
+		mii_mgr_write(priv, i, 31, 0xa000);	/* change L2 page */
+		mii_mgr_write(priv, i, 16, 0x0606);
+		mii_mgr_write(priv, i, 23, 0x0f0e);
+		mii_mgr_write(priv, i, 24, 0x1610);
+		mii_mgr_write(priv, i, 30, 0x1f15);
+		mii_mgr_write(priv, i, 28, 0x6111);
+	}
+
+	/* 100Base AOI setting */
+	mii_mgr_write(priv, 0, 31, 0x5000);	/* change G5 page */
+	mii_mgr_write(priv, 0, 19, 0x004a);
+	mii_mgr_write(priv, 0, 20, 0x015a);
+	mii_mgr_write(priv, 0, 21, 0x00ee);
+	mii_mgr_write(priv, 0, 22, 0x0033);
+	mii_mgr_write(priv, 0, 23, 0x020a);
+	mii_mgr_write(priv, 0, 24, 0x0000);
+	mii_mgr_write(priv, 0, 25, 0x024a);
+	mii_mgr_write(priv, 0, 26, 0x035a);
+	mii_mgr_write(priv, 0, 27, 0x02ee);
+	mii_mgr_write(priv, 0, 28, 0x0233);
+	mii_mgr_write(priv, 0, 29, 0x000a);
+	mii_mgr_write(priv, 0, 30, 0x0000);
+
+	/* Fix EPHY idle state abnormal behavior */
+	mii_mgr_write(priv, 0, 31, 0x4000);	/* change G4 page */
+	mii_mgr_write(priv, 0, 29, 0x000d);
+	mii_mgr_write(priv, 0, 30, 0x0500);
+}
+
+static void rt305x_esw_init(struct mt76xx_eth_dev *priv)
+{
+	void __iomem *base = priv->eth_sw_base;
+
+	/*
+	 * FC_RLS_TH=200, FC_SET_TH=160
+	 * DROP_RLS=120, DROP_SET_TH=80
+	 */
+	writel(0xc8a07850, base + MT76XX_SWITCH_FCT0);
+	writel(0x00000000, base + MT76XX_SWITCH_SGC2);
+	writel(0x00405555, base + MT76XX_SWITCH_PFC1);
+	writel(0x00007f7f, base + MT76XX_SWITCH_POC0);
+	writel(0x00007f7f, base + MT76XX_SWITCH_POC2);	/* disable VLAN */
+	writel(0x0002500c, base + MT76XX_SWITCH_FCT2);
+	/* hashing algorithm=XOR48, aging interval=300sec */
+	writel(0x0008a301, base + MT76XX_SWITCH_SGC);
+	writel(0x02404040, base + MT76XX_SWITCH_SOCPC);
+
+	/* Ext PHY Addr=0x1f */
+	writel(0x3f502b28, base + MT76XX_SWITCH_FPA1);
+	writel(0x00000000, base + MT76XX_SWITCH_FPA);
+	/* 1us cycle number=125 (FE's clock=125Mhz) */
+	writel(0x7d000000, base + MT76XX_SWITCH_BMU_CTRL);
+
+	/* Configure analog GPIO setup */
+	regmap_update_bits(priv->sysctrl_regmap, MT76XX_AGPIO_CFG_REG,
+			   MT7628_EPHY_P0_DIS, MT7628_EPHY_GPIO_AIO_EN);
+
+	/* Reset PHY */
+	regmap_update_bits(priv->sysctrl_regmap, MT76XX_RSTCTRL_REG,
+			   0, RSTCTRL_EPHY_RST);
+	regmap_update_bits(priv->sysctrl_regmap, MT76XX_RSTCTRL_REG,
+			   RSTCTRL_EPHY_RST, 0);
+	mdelay(10);
+
+	/* Set P0 EPHY LED mode */
+	regmap_update_bits(priv->sysctrl_regmap, MT76XX_GPIO2_MODE_REG,
+			   0x0ffc0ffc, 0x05540554);
+	mdelay(10);
+
+	mt7628_ephy_init(priv);
+}
+
+static void eth_dma_start(struct mt76xx_eth_dev *priv)
+{
+	void __iomem *base = priv->base;
+
+	setbits_le32(base + PDMA_GLO_CFG, TX_WB_DDONE | RX_DMA_EN | TX_DMA_EN);
+}
+
+static void eth_dma_stop(struct mt76xx_eth_dev *priv)
+{
+	void __iomem *base = priv->base;
+	int ret;
+
+	clrbits_le32(base + PDMA_GLO_CFG, TX_WB_DDONE | RX_DMA_EN | TX_DMA_EN);
+
+	/* Wait for DMA to stop */
+	ret = wait_for_bit_le32(base + PDMA_GLO_CFG,
+				RX_DMA_BUSY | TX_DMA_BUSY, false,
+				CONFIG_DMA_STOP_TIMEOUT, false);
+	if (ret)
+		printf("DMA stop timeout error!\n");
+}
+
+static int mt76xx_eth_write_hwaddr(struct udevice *dev)
+{
+	struct mt76xx_eth_dev *priv = dev_get_priv(dev);
+	void __iomem *base = priv->base;
+	u8 *addr = ((struct eth_pdata *)dev_get_platdata(dev))->enetaddr;
+	u32 val;
+	u16 tmp;
+
+	/* Set MAC address. */
+	tmp = (u16)addr[0];
+	val = (tmp << 8) | addr[1];
+
+	writel(val, base + SDM_MAC_ADRH);
+
+	tmp = (u16)addr[2];
+	val = (tmp << 8) | addr[3];
+	val = val << 16;
+	tmp = (u16)addr[4];
+	val |= (tmp << 8) | addr[5];
+	writel(val, base + SDM_MAC_ADRL);
+
+	return 0;
+}
+
+static int mt76xx_eth_send(struct udevice *dev, void *packet, int length)
+{
+	struct mt76xx_eth_dev *priv = dev_get_priv(dev);
+	void __iomem *base = priv->base;
+	int ret;
+	int idx;
+	int i;
+
+	idx = priv->tx_dma_idx;
+
+	/* Pad message to a minimum length */
+	if (length < PADDING_LENGTH) {
+		char *p = (char *)packet;
+
+		for (i = 0; i < PADDING_LENGTH - length; i++)
+			p[length + i] = 0;
+		length = PADDING_LENGTH;
+	}
+
+	/* Check if buffer is ready for next TX DMA */
+	ret = wait_for_bit_le32(&priv->tx_ring[idx].txd2, TX_DMA_DONE, true,
+				CONFIG_TX_DMA_TIMEOUT, false);
+	if (ret) {
+		printf("TX: DMA still busy on buffer %d\n", idx);
+		return ret;
+	}
+
+	flush_dcache_range((u32)packet, (u32)packet + length);
+
+	priv->tx_ring[idx].txd1 = CPHYSADDR(packet);
+	priv->tx_ring[idx].txd2 |= TX_DMA_PLEN0(length);
+	priv->tx_ring[idx].txd2 &= ~TX_DMA_DONE;
+
+	idx = (idx + 1) % NUM_TX_DESC;
+
+	/* Make sure the writes exceuted at this place */
+	wmb();
+	writel(idx, base + TX_CTX_IDX0);
+
+	priv->tx_dma_idx = idx;
+
+	return 0;
+}
+
+static int mt76xx_eth_recv(struct udevice *dev, int flags, uchar **packetp)
+{
+	struct mt76xx_eth_dev *priv = dev_get_priv(dev);
+	void __iomem *base = priv->base;
+	u32 rxd_info;
+	int length;
+	int idx;
+
+	idx = priv->rx_dma_idx;
+
+	rxd_info = priv->rx_ring[idx].rxd2;
+	if ((rxd_info & RX_DMA_DONE) == 0)
+		return -EAGAIN;
+
+	length = RX_DMA_GET_PLEN0(priv->rx_ring[idx].rxd2);
+	if (length == 0 || length > MTK_QDMA_PAGE_SIZE) {
+		printf("%s: invalid length (%d bytes)\n", __func__, length);
+		return -EIO;
+	}
+
+	*packetp = priv->rx_buf[idx];
+	invalidate_dcache_range((u32)*packetp, (u32)*packetp + length);
+
+	priv->rx_ring[idx].rxd4 = 0;
+	priv->rx_ring[idx].rxd2 = RX_DMA_LSO;
+
+	/* Make sure the writes exceuted at this place */
+	wmb();
+
+	/* Move point to next RXD which wants to alloc */
+	writel(idx, base + RX_CALC_IDX0);
+
+	/* Update to Next packet point that was received */
+	idx = (idx + 1) % NUM_RX_DESC;
+
+	priv->rx_dma_idx = idx;
+
+	return length;
+}
+
+static int phy_link_up(struct mt76xx_eth_dev *priv)
+{
+	u32 val;
+
+	mii_mgr_read(priv, 0x00, MII_BMSR, &val);
+	return !!(val & BMSR_LSTATUS);
+}
+
+static int mt76xx_eth_start(struct udevice *dev)
+{
+	struct mt76xx_eth_dev *priv = dev_get_priv(dev);
+	void __iomem *base = priv->base;
+	uchar packet[MTK_QDMA_PAGE_SIZE];
+	uchar *packetp;
+	int i;
+
+	for (i = 0; i < NUM_RX_DESC; i++) {
+		memset((void *)&priv->rx_ring[i], 0, sizeof(priv->rx_ring[0]));
+		priv->rx_ring[i].rxd2 |= RX_DMA_LSO;
+		priv->rx_ring[i].rxd1 = CPHYSADDR(priv->rx_buf[i]);
+	}
+
+	for (i = 0; i < NUM_TX_DESC; i++) {
+		memset((void *)&priv->tx_ring[i], 0, sizeof(priv->tx_ring[0]));
+		priv->tx_ring[i].txd2 = TX_DMA_LS0 | TX_DMA_DONE;
+		priv->tx_ring[i].txd4 = TX_DMA_PN(1);
+	}
+
+	priv->rx_dma_idx = 0;
+	priv->tx_dma_idx = 0;
+
+	/* Make sure the writes exceuted at this place */
+	wmb();
+
+	/* disable delay interrupt */
+	writel(0, base + DLY_INT_CFG);
+
+	clrbits_le32(base + PDMA_GLO_CFG, 0xffff0000);
+
+	/* Tell the adapter where the TX/RX rings are located. */
+	writel(CPHYSADDR(&priv->rx_ring[0]), base + RX_BASE_PTR0);
+	writel(CPHYSADDR((u32)&priv->tx_ring[0]), base + TX_BASE_PTR0);
+
+	writel(NUM_RX_DESC, base + RX_MAX_CNT0);
+	writel(NUM_TX_DESC, base + TX_MAX_CNT0);
+
+	writel(priv->tx_dma_idx, base + TX_CTX_IDX0);
+	writel(RST_DTX_IDX0, base + PDMA_RST_IDX);
+
+	writel(NUM_RX_DESC - 1, base + RX_CALC_IDX0);
+	writel(RST_DRX_IDX0, base + PDMA_RST_IDX);
+
+	/* Make sure the writes exceuted at this place */
+	wmb();
+	eth_dma_start(priv);
+
+	/* Check if link is not up yet */
+	if (!phy_link_up(priv)) {
+		/* Wait for link to come up */
+
+		printf("Waiting for link to come up .");
+		for (i = 0; i < (LINK_TIMEOUT / LINK_DELAY_TIME); i++) {
+			mdelay(LINK_DELAY_TIME);
+			if (phy_link_up(priv)) {
+				mdelay(100);	/* Ensure all is ready */
+				break;
+			}
+
+			printf(".");
+		}
+
+		if (phy_link_up(priv))
+			printf(" done\n");
+		else
+			printf(" timeout! Trying anyways\n");
+	}
+
+	/*
+	 * The integrated switch seems to queue some received ethernet
+	 * packets in some FIFO. Lets read the already queued packets
+	 * out by using the reveice routine, so that these old messages
+	 * are dropped before the new xfer starts.
+	 */
+	packetp = &packet[0];
+	while (mt76xx_eth_recv(dev, 0, &packetp) != -EAGAIN)
+		;
+
+	return 0;
+}
+
+static void mt76xx_eth_stop(struct udevice *dev)
+{
+	struct mt76xx_eth_dev *priv = dev_get_priv(dev);
+
+	eth_dma_stop(priv);
+}
+
+static int mt76xx_eth_probe(struct udevice *dev)
+{
+	struct mt76xx_eth_dev *priv = dev_get_priv(dev);
+	struct udevice *syscon;
+	struct mii_dev *bus;
+	int ret;
+	int i;
+
+	/* Save frame-engine base address for later use */
+	priv->base = dev_remap_addr_index(dev, 0);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	/* Save switch base address for later use */
+	priv->eth_sw_base = dev_remap_addr_index(dev, 1);
+	if (IS_ERR(priv->eth_sw_base))
+		return PTR_ERR(priv->eth_sw_base);
+
+	/* Get system controller regmap */
+	ret = uclass_get_device_by_phandle(UCLASS_SYSCON, dev,
+					   "syscon", &syscon);
+	if (ret) {
+		pr_err("unable to find syscon device\n");
+		return ret;
+	}
+
+	priv->sysctrl_regmap = syscon_get_regmap(syscon);
+	if (!priv->sysctrl_regmap) {
+		pr_err("unable to find regmap\n");
+		return -ENODEV;
+	}
+
+	/* Put rx and tx rings into KSEG1 area (uncached) */
+	priv->tx_ring = (struct fe_tx_dma *)
+		KSEG1ADDR(memalign(ARCH_DMA_MINALIGN,
+				   sizeof(*priv->tx_ring) * NUM_TX_DESC));
+	priv->rx_ring = (struct fe_rx_dma *)
+		KSEG1ADDR(memalign(ARCH_DMA_MINALIGN,
+				   sizeof(*priv->rx_ring) * NUM_RX_DESC));
+
+	for (i = 0; i < NUM_RX_DESC; i++)
+		priv->rx_buf[i] = memalign(PKTALIGN, MTK_QDMA_PAGE_SIZE);
+
+	bus = mdio_alloc();
+	if (!bus) {
+		printf("Failed to allocate MDIO bus\n");
+		return -ENOMEM;
+	}
+
+	bus->read = mt76xx_mdio_read;
+	bus->write = mt76xx_mdio_write;
+	snprintf(bus->name, sizeof(bus->name), dev->name);
+	bus->priv = (void *)priv;
+
+	ret = mdio_register(bus);
+	if (ret)
+		return ret;
+
+	/* Switch configuration */
+	rt305x_esw_init(priv);
+
+	return 0;
+}
+
+static const struct eth_ops mt76xx_eth_ops = {
+	.start		= mt76xx_eth_start,
+	.send		= mt76xx_eth_send,
+	.recv		= mt76xx_eth_recv,
+	.stop		= mt76xx_eth_stop,
+	.write_hwaddr	= mt76xx_eth_write_hwaddr,
+};
+
+static const struct udevice_id mt76xx_eth_ids[] = {
+	{ .compatible = "mediatek,mt7622-eth" },
+	{ }
+};
+
+U_BOOT_DRIVER(mt76xx_eth) = {
+	.name	= "mt76xx_eth",
+	.id	= UCLASS_ETH,
+	.of_match = mt76xx_eth_ids,
+	.probe	= mt76xx_eth_probe,
+	.ops	= &mt76xx_eth_ops,
+	.priv_auto_alloc_size = sizeof(struct mt76xx_eth_dev),
+	.platdata_auto_alloc_size = sizeof(struct eth_pdata),
+};
-- 
2.19.1