[PATCH v2 2/4] net: dsa: add new DSA switch driver for the SMSC-LAN9303

[Juergen Borleis <jbe@pengutronix.de>]

The SMSC/Microchip LAN9303 is an ethernet switch device with one CPU port
and two external ethernet ports with built-in phys.

This driver uses the DSA framework, but is currently only capable of
separating the two external ports. There is no offload support yet.

Signed-off-by: Juergen Borleis <jbe@pengutronix.de>
---
 drivers/net/dsa/lan9303-core.c | 884 +++++++++++++++++++++++++++++++++++++++++
 drivers/net/dsa/lan9303.h      |  24 ++
 2 files changed, 908 insertions(+)
 create mode 100644 drivers/net/dsa/lan9303-core.c
 create mode 100644 drivers/net/dsa/lan9303.h

diff --git a/drivers/net/dsa/lan9303-core.c b/drivers/net/dsa/lan9303-core.c
new file mode 100644
index 0000000000000..f790294f1a0fe
--- /dev/null
+++ b/drivers/net/dsa/lan9303-core.c
@@ -0,0 +1,884 @@
+/*
+ * Copyright (C) 2017 Pengutronix, Juergen Borleis <kernel@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/gpio/consumer.h>
+#include <linux/regmap.h>
+#include <linux/mutex.h>
+#include <linux/mii.h>
+
+#include "lan9303.h"
+
+#define LAN9303_CHIP_REV 0x14
+# define LAN9303_CHIP_ID 0x9303
+#define LAN9303_IRQ_CFG 0x15
+# define LAN9303_IRQ_CFG_IRQ_ENABLE BIT(8)
+# define LAN9303_IRQ_CFG_IRQ_POL BIT(4)
+# define LAN9303_IRQ_CFG_IRQ_TYPE BIT(0)
+#define LAN9303_INT_STS 0x16
+# define LAN9303_INT_STS_PHY_INT2 BIT(27)
+# define LAN9303_INT_STS_PHY_INT1 BIT(26)
+#define LAN9303_INT_EN 0x17
+# define LAN9303_INT_EN_PHY_INT2_EN BIT(27)
+# define LAN9303_INT_EN_PHY_INT1_EN BIT(26)
+#define LAN9303_HW_CFG 0x1D
+# define LAN9303_HW_CFG_READY BIT(27)
+# define LAN9303_HW_CFG_AMDX_EN_PORT2 BIT(26)
+# define LAN9303_HW_CFG_AMDX_EN_PORT1 BIT(25)
+#define LAN9303_PMI_DATA 0x29
+#define LAN9303_PMI_ACCESS 0x2A
+# define LAN9303_PMI_ACCESS_PHY_ADDR(x) (((x) & 0x1f) << 11)
+# define LAN9303_PMI_ACCESS_MIIRINDA(x) (((x) & 0x1f) << 6)
+# define LAN9303_PMI_ACCESS_MII_BUSY BIT(0)
+# define LAN9303_PMI_ACCESS_MII_WRITE BIT(1)
+#define LAN9303_MANUAL_FC_1 0x68
+#define LAN9303_MANUAL_FC_2 0x69
+#define LAN9303_MANUAL_FC_0 0x6a
+#define LAN9303_SWITCH_CSR_DATA 0x6b
+#define LAN9303_SWITCH_CSR_CMD 0x6c
+#define LAN9303_SWITCH_CSR_CMD_BUSY BIT(31)
+#define LAN9303_SWITCH_CSR_CMD_RW BIT(30)
+#define LAN9303_SWITCH_CSR_CMD_LANES (BIT(19) | BIT(18) | BIT(17) | BIT(16))
+#define LAN9303_VIRT_PHY_BASE 0x70
+#define LAN9303_VIRT_SPECIAL_CTRL 0x77
+
+#define LAN9303_SW_DEV_ID 0x0000
+#define LAN9303_SW_RESET 0x0001
+#define LAN9303_SW_RESET_RESET BIT(0)
+#define LAN9303_SW_IMR 0x0004
+#define LAN9303_SW_IPR 0x0005
+#define LAN9303_MAC_VER_ID_0 0x0400
+#define LAN9303_MAC_RX_CFG_0 0x0401
+# define LAN9303_MAC_RX_CFG_X_REJECT_MAC_TYPES BIT(1)
+# define LAN9303_MAC_RX_CFG_X_RX_ENABLE BIT(0)
+#define LAN9303_MAC_RX_UNDSZE_CNT_0 0x0410
+#define LAN9303_MAC_RX_64_CNT_0 0x0411
+#define LAN9303_MAC_RX_127_CNT_0 0x0412
+#define LAN9303_MAC_RX_255_CNT_0 0x413
+#define LAN9303_MAC_RX_511_CNT_0 0x0414
+#define LAN9303_MAC_RX_1023_CNT_0 0x0415
+#define LAN9303_MAC_RX_MAX_CNT_0 0x0416
+#define LAN9303_MAC_RX_OVRSZE_CNT_0 0x0417
+#define LAN9303_MAC_RX_PKTOK_CNT_0 0x0418
+#define LAN9303_MAC_RX_CRCERR_CNT_0 0x0419
+#define LAN9303_MAC_RX_MULCST_CNT_0 0x041a
+#define LAN9303_MAC_RX_BRDCST_CNT_0 0x041b
+#define LAN9303_MAC_RX_PAUSE_CNT_0 0x041c
+#define LAN9303_MAC_RX_FRAG_CNT_0 0x041d
+#define LAN9303_MAC_RX_JABB_CNT_0 0x041e
+#define LAN9303_MAC_RX_ALIGN_CNT_0 0x041f
+#define LAN9303_MAC_RX_PKTLEN_CNT_0 0x0420
+#define LAN9303_MAC_RX_GOODPKTLEN_CNT_0 0x0421
+#define LAN9303_MAC_RX_SYMBL_CNT_0 0x0422
+#define LAN9303_MAC_RX_CTLFRM_CNT_0 0x0423
+
+#define LAN9303_MAC_TX_CFG_0 0x0440
+# define LAN9303_MAC_TX_CFG_X_TX_IFG_CONFIG_DEFAULT (21 << 2)
+# define LAN9303_MAC_TX_CFG_X_TX_PAD_ENABLE BIT(1)
+# define LAN9303_MAC_TX_CFG_X_TX_ENABLE BIT(0)
+#define LAN9303_MAC_TX_DEFER_CNT_0 0x0451
+#define LAN9303_MAC_TX_PAUSE_CNT_0 0x0452
+#define LAN9303_MAC_TX_PKTOK_CNT_0 0x0453
+#define LAN9303_MAC_TX_64_CNT_0 0x0454
+#define LAN9303_MAC_TX_127_CNT_0 0x0455
+#define LAN9303_MAC_TX_255_CNT_0 0x0456
+#define LAN9303_MAC_TX_511_CNT_0 0x0457
+#define LAN9303_MAC_TX_1023_CNT_0 0x0458
+#define LAN9303_MAC_TX_MAX_CNT_0 0x0459
+#define LAN9303_MAC_TX_UNDSZE_CNT_0 0x045a
+#define LAN9303_MAC_TX_PKTLEN_CNT_0 0x045c
+#define LAN9303_MAC_TX_BRDCST_CNT_0 0x045d
+#define LAN9303_MAC_TX_MULCST_CNT_0 0x045e
+#define LAN9303_MAC_TX_LATECOL_0 0x045f
+#define LAN9303_MAC_TX_EXCOL_CNT_0 0x0460
+#define LAN9303_MAC_TX_SNGLECOL_CNT_0 0x0461
+#define LAN9303_MAC_TX_MULTICOL_CNT_0 0x0462
+#define LAN9303_MAC_TX_TOTALCOL_CNT_0 0x0463
+
+#define LAN9303_MAC_VER_ID_1 0x0800
+#define LAN9303_MAC_RX_CFG_1 0x0801
+#define LAN9303_MAC_TX_CFG_1 0x0840
+#define LAN9303_MAC_VER_ID_2 0x0c00
+#define LAN9303_MAC_RX_CFG_2 0x0c01
+#define LAN9303_MAC_TX_CFG_2 0x0c40
+#define LAN9303_SWE_ALR_CMD 0x1800
+#define LAN9303_SWE_VLAN_CMD 0x180b
+# define LAN9303_SWE_VLAN_CMD_RNW BIT(5)
+# define LAN9303_SWE_VLAN_CMD_PVIDNVLAN BIT(4)
+#define LAN9303_SWE_VLAN_WR_DATA 0x180c
+#define LAN9303_SWE_VLAN_RD_DATA 0x180e
+# define LAN9303_SWE_VLAN_MEMBER_PORT2 BIT(17)
+# define LAN9303_SWE_VLAN_UNTAG_PORT2 BIT(16)
+# define LAN9303_SWE_VLAN_MEMBER_PORT1 BIT(15)
+# define LAN9303_SWE_VLAN_UNTAG_PORT1 BIT(14)
+# define LAN9303_SWE_VLAN_MEMBER_PORT0 BIT(13)
+# define LAN9303_SWE_VLAN_UNTAG_PORT0 BIT(12)
+#define LAN9303_SWE_VLAN_CMD_STS 0x1810
+#define LAN9303_SWE_GLB_INGRESS_CFG 0x1840
+#define LAN9303_SWE_PORT_STATE 0x1843
+# define LAN9303_SWE_PORT_STATE_FORWARDING_PORT2 (0)
+# define LAN9303_SWE_PORT_STATE_LEARNING_PORT2 BIT(5)
+# define LAN9303_SWE_PORT_STATE_BLOCKING_PORT2 BIT(4)
+# define LAN9303_SWE_PORT_STATE_FORWARDING_PORT1 (0)
+# define LAN9303_SWE_PORT_STATE_LEARNING_PORT1 BIT(3)
+# define LAN9303_SWE_PORT_STATE_BLOCKING_PORT1 BIT(2)
+# define LAN9303_SWE_PORT_STATE_FORWARDING_PORT0 (0)
+# define LAN9303_SWE_PORT_STATE_LEARNING_PORT0 BIT(1)
+# define LAN9303_SWE_PORT_STATE_BLOCKING_PORT0 BIT(0)
+#define LAN9303_SWE_PORT_MIRROR 0x1846
+# define LAN9303_SWE_PORT_MIRROR_SNIFF_ALL BIT(8)
+# define LAN9303_SWE_PORT_MIRROR_SNIFFER_PORT2 BIT(7)
+# define LAN9303_SWE_PORT_MIRROR_SNIFFER_PORT1 BIT(6)
+# define LAN9303_SWE_PORT_MIRROR_SNIFFER_PORT0 BIT(5)
+# define LAN9303_SWE_PORT_MIRROR_MIRRORED_PORT2 BIT(4)
+# define LAN9303_SWE_PORT_MIRROR_MIRRORED_PORT1 BIT(3)
+# define LAN9303_SWE_PORT_MIRROR_MIRRORED_PORT0 BIT(2)
+# define LAN9303_SWE_PORT_MIRROR_ENABLE_RX_MIRRORING BIT(1)
+# define LAN9303_SWE_PORT_MIRROR_ENABLE_TX_MIRRORING BIT(0)
+#define LAN9303_SWE_INGRESS_PORT_TYPE 0x1847
+#define LAN9303_BM_CFG 0x1c00
+#define LAN9303_BM_EGRSS_PORT_TYPE 0x1c0c
+# define LAN9303_BM_EGRSS_PORT_TYPE_SPECIAL_TAG_PORT2 (BIT(17) | BIT(16))
+# define LAN9303_BM_EGRSS_PORT_TYPE_SPECIAL_TAG_PORT1 (BIT(9) | BIT(8))
+# define LAN9303_BM_EGRSS_PORT_TYPE_SPECIAL_TAG_PORT0 (BIT(1) | BIT(0))
+
+#define LAN9303_PORT_0_OFFSET 0x400
+#define LAN9303_PORT_1_OFFSET 0x800
+#define LAN9303_PORT_2_OFFSET 0xc00
+
+/* the built-in PHYs are of type LAN911X */
+#define MII_LAN911X_SPECIAL_MODES 0x12
+#define MII_LAN911X_SPECIAL_CONTROL_STATUS 0x1f
+
+static const struct regmap_range lan9303_valid_regs[] = {
+	regmap_reg_range(0x14, 0x17), /* misc, interrupt */
+	regmap_reg_range(0x19, 0x19), /* endian test */
+	regmap_reg_range(0x1d, 0x1d), /* hardware config */
+	regmap_reg_range(0x23, 0x24), /* general purpose timer */
+	regmap_reg_range(0x27, 0x27), /* counter */
+	regmap_reg_range(0x29, 0x2a), /* PMI index regs */
+	regmap_reg_range(0x68, 0x6a), /* flow control */
+	regmap_reg_range(0x6b, 0x6c), /* switch fabric indirect regs */
+	regmap_reg_range(0x6d, 0x6f), /* misc */
+	regmap_reg_range(0x70, 0x77), /* virtual phy */
+	regmap_reg_range(0x78, 0x7a), /* GPIO */
+	regmap_reg_range(0x7c, 0x7e), /* MAC & reset */
+	regmap_reg_range(0x80, 0xb7), /* switch fabric direct regs (wr only) */
+};
+
+static const struct regmap_range lan9303_reserved_ranges[] = {
+	regmap_reg_range(0x00, 0x13),
+	regmap_reg_range(0x18, 0x18),
+	regmap_reg_range(0x1a, 0x1c),
+	regmap_reg_range(0x1e, 0x22),
+	regmap_reg_range(0x25, 0x26),
+	regmap_reg_range(0x28, 0x28),
+	regmap_reg_range(0x2b, 0x67),
+	regmap_reg_range(0x7b, 0x7b),
+	regmap_reg_range(0x7f, 0x7f),
+	regmap_reg_range(0xb8, 0xff),
+};
+
+const struct regmap_access_table lan9303_register_set = {
+	.yes_ranges = lan9303_valid_regs,
+	.n_yes_ranges = ARRAY_SIZE(lan9303_valid_regs),
+	.no_ranges = lan9303_reserved_ranges,
+	.n_no_ranges = ARRAY_SIZE(lan9303_reserved_ranges),
+};
+
+static int lan9303_read(struct regmap *regmap, unsigned int offset, u32 *reg)
+{
+	int ret, i;
+
+	/* we can lose arbitration for the I2C case, because the device
+	 * tries to detect and read an external EEPROM after reset and acts as
+	 * a master on the shared I2C bus itself. This conflicts with our
+	 * attempts to access the device as a slave at the same moment.
+	 */
+	for (i = 0; i < 5; i++) {
+		ret = regmap_read(regmap, offset, reg);
+		if (!ret)
+			return 0;
+		if (ret != -EAGAIN)
+			break;
+		msleep(500);
+	}
+
+	return -EIO;
+}
+
+static int lan9303_virt_phy_reg_read(struct lan9303 *chip, int regnum)
+{
+	int ret;
+	u32 val;
+
+	if (regnum > MII_EXPANSION) {
+		if (regnum == MII_LAN911X_SPECIAL_CONTROL_STATUS)
+			regnum = 7; /* map to LAN9303_VIRT_SPECIAL_CTRL */
+		else
+			return -EINVAL;
+	}
+
+	ret = lan9303_read(chip->regmap, LAN9303_VIRT_PHY_BASE + regnum, &val);
+	if (ret)
+		return ret;
+
+	return val & 0xffff;
+}
+
+static int lan9303_virt_phy_reg_write(struct lan9303 *chip, int regnum, u16 val)
+{
+	if (regnum > MII_EXPANSION) {
+		if (regnum == MII_LAN911X_SPECIAL_CONTROL_STATUS)
+			regnum = 7; /* map to LAN9303_VIRT_SPECIAL_CTRL */
+		else
+			return -EINVAL;
+	}
+
+	return regmap_write(chip->regmap, LAN9303_VIRT_PHY_BASE + regnum, val);
+}
+
+static int lan9303_port_phy_reg_wait_for_completion(struct lan9303 *chip)
+{
+	int ret, i;
+	u32 reg;
+
+	for (i = 0; i < 25; i++) {
+		ret = lan9303_read(chip->regmap, LAN9303_PMI_ACCESS, &reg);
+		if (ret) {
+			dev_err(chip->dev,
+				"Failed to read pmi access status: %d\n", ret);
+			return ret;
+		}
+		if (!(reg & LAN9303_PMI_ACCESS_MII_BUSY))
+			return 0;
+		msleep(1);
+	}
+
+	return -EIO;
+}
+
+static int lan9303_port_phy_reg_read(struct lan9303 *chip, int addr, int regnum)
+{
+	int ret;
+	u32 val;
+
+	val = LAN9303_PMI_ACCESS_PHY_ADDR(addr);
+	val |= LAN9303_PMI_ACCESS_MIIRINDA(regnum);
+
+	mutex_lock(&chip->indirect_mutex);
+
+	ret = lan9303_port_phy_reg_wait_for_completion(chip);
+	if (ret)
+		goto on_error;
+
+	/* start the MII read cycle */
+	ret = regmap_write(chip->regmap, LAN9303_PMI_ACCESS, val);
+	if (ret)
+		goto on_error;
+
+	ret = lan9303_port_phy_reg_wait_for_completion(chip);
+	if (ret)
+		goto on_error;
+
+	/* read the result of this operation */
+	ret = lan9303_read(chip->regmap, LAN9303_PMI_DATA, &val);
+	if (ret)
+		goto on_error;
+
+	mutex_unlock(&chip->indirect_mutex);
+
+	return val & 0xffff;
+
+on_error:
+	mutex_unlock(&chip->indirect_mutex);
+	return ret;
+}
+
+static int lan9303_phy_reg_write(struct lan9303 *chip, int addr, int regnum,
+				 unsigned int val)
+{
+	int ret;
+	u32 reg;
+
+	reg = LAN9303_PMI_ACCESS_PHY_ADDR(addr);
+	reg |= LAN9303_PMI_ACCESS_MIIRINDA(regnum);
+	reg |= LAN9303_PMI_ACCESS_MII_WRITE;
+
+	mutex_lock(&chip->indirect_mutex);
+
+	ret = lan9303_port_phy_reg_wait_for_completion(chip);
+	if (ret)
+		goto on_error;
+
+	/* write the data first... */
+	ret = regmap_write(chip->regmap, LAN9303_PMI_DATA, val);
+	if (ret)
+		goto on_error;
+
+	/* ...then start the MII write cycle */
+	ret = regmap_write(chip->regmap, LAN9303_PMI_ACCESS, reg);
+
+on_error:
+	mutex_unlock(&chip->indirect_mutex);
+	return ret;
+}
+
+static int lan9303_switch_wait_for_completion(struct lan9303 *chip)
+{
+	int ret, i;
+	u32 reg;
+
+	for (i = 0; i < 25; i++) {
+		ret = lan9303_read(chip->regmap, LAN9303_SWITCH_CSR_CMD, &reg);
+		if (ret) {
+			dev_err(chip->dev,
+				"Failed to read csr command status: %d\n", ret);
+			return ret;
+		}
+		if (!(reg & LAN9303_SWITCH_CSR_CMD_BUSY))
+			return 0;
+		msleep(1);
+	}
+
+	return -EIO;
+}
+
+static int lan9303_write_switch_reg(struct lan9303 *chip, u16 regnum, u32 val)
+{
+	u32 reg;
+	int ret;
+
+	reg = regnum;
+	reg |= LAN9303_SWITCH_CSR_CMD_LANES;
+	reg |= LAN9303_SWITCH_CSR_CMD_BUSY;
+
+	mutex_lock(&chip->indirect_mutex);
+
+	ret = lan9303_switch_wait_for_completion(chip);
+	if (ret)
+		goto on_error;
+
+	ret = regmap_write(chip->regmap, LAN9303_SWITCH_CSR_DATA, val);
+	if (ret) {
+		dev_err(chip->dev, "Failed to write csr data reg: %d\n", ret);
+		goto on_error;
+	}
+
+	/* trigger write */
+	ret = regmap_write(chip->regmap, LAN9303_SWITCH_CSR_CMD, reg);
+	if (ret)
+		dev_err(chip->dev, "Failed to write csr command reg: %d\n",
+			ret);
+
+on_error:
+	mutex_unlock(&chip->indirect_mutex);
+	return ret;
+}
+
+static int lan9303_read_switch_reg(struct lan9303 *chip, u16 regnum, u32 *val)
+{
+	u32 reg;
+	int ret;
+
+	reg = regnum;
+	reg |= LAN9303_SWITCH_CSR_CMD_LANES;
+	reg |= LAN9303_SWITCH_CSR_CMD_RW;
+	reg |= LAN9303_SWITCH_CSR_CMD_BUSY;
+
+	mutex_lock(&chip->indirect_mutex);
+
+	ret = lan9303_switch_wait_for_completion(chip);
+	if (ret)
+		goto on_error;
+
+	/* trigger read */
+	ret = regmap_write(chip->regmap, LAN9303_SWITCH_CSR_CMD, reg);
+	if (ret) {
+		dev_err(chip->dev, "Failed to write csr command reg: %d\n",
+			ret);
+		goto on_error;
+	}
+
+	ret = lan9303_switch_wait_for_completion(chip);
+	if (ret)
+		goto on_error;
+
+	ret = lan9303_read(chip->regmap, LAN9303_SWITCH_CSR_DATA, val);
+	if (ret)
+		dev_err(chip->dev, "Failed to read csr data reg: %d\n", ret);
+on_error:
+	mutex_unlock(&chip->indirect_mutex);
+	return ret;
+}
+
+static int lan9303_detect_phy_setup(struct lan9303 *chip)
+{
+	int reg;
+
+	/* depending on the 'phy_addr_sel_strap' setting, the three phys are
+	 * using IDs 0-1-2 or IDs 1-2-3. We cannot read back the
+	 * 'phy_addr_sel_strap' setting directly, so we need a test, which
+	 * configuration is active:
+	 * Special reg 18 of phy 3 reads as 0x0000, if 'phy_addr_sel_strap' is 0
+	 * and the IDs are 0-1-2, else it contains something different from
+	 * 0x0000, which means 'phy_addr_sel_strap' is 1 and the IDs are 1-2-3.
+	 */
+	reg = lan9303_port_phy_reg_read(chip, 3, MII_LAN911X_SPECIAL_MODES);
+	if (reg < 0) {
+		dev_err(chip->dev, "Failed to detect phy config: %d\n", reg);
+		return reg;
+	}
+
+	if (reg != 0)
+		chip->phy_addr_sel_strap = 1;
+	else
+		chip->phy_addr_sel_strap = 0;
+
+	dev_dbg(chip->dev, "Phy setup '%s' detected\n",
+		chip->phy_addr_sel_strap ? "1-2-3" : "0-1-2");
+
+	return 0;
+}
+
+#define LAN9303_MAC_RX_CFG_OFFS (LAN9303_MAC_RX_CFG_0 - LAN9303_PORT_0_OFFSET)
+#define LAN9303_MAC_TX_CFG_OFFS (LAN9303_MAC_TX_CFG_0 - LAN9303_PORT_0_OFFSET)
+
+static int lan9303_disable_packet_processing(struct lan9303 *chip,
+					     unsigned int port)
+{
+	int ret;
+
+	/* disable RX, but keep register reset default values else */
+	ret = lan9303_write_switch_reg(chip, LAN9303_MAC_RX_CFG_OFFS + port,
+				       LAN9303_MAC_RX_CFG_X_REJECT_MAC_TYPES);
+	if (ret)
+		return ret;
+
+	/* disable TX, but keep register reset default values else */
+	return lan9303_write_switch_reg(chip, LAN9303_MAC_TX_CFG_OFFS + port,
+				LAN9303_MAC_TX_CFG_X_TX_IFG_CONFIG_DEFAULT |
+				LAN9303_MAC_TX_CFG_X_TX_PAD_ENABLE);
+}
+
+static int lan9303_enable_packet_processing(struct lan9303 *chip,
+					    unsigned int port)
+{
+	int ret;
+
+	/* enable RX and keep register reset default values else */
+	ret = lan9303_write_switch_reg(chip, LAN9303_MAC_RX_CFG_OFFS + port,
+				       LAN9303_MAC_RX_CFG_X_REJECT_MAC_TYPES |
+				       LAN9303_MAC_RX_CFG_X_RX_ENABLE);
+	if (ret)
+		return ret;
+
+	/* enable TX and keep register reset default values else */
+	return lan9303_write_switch_reg(chip, LAN9303_MAC_TX_CFG_OFFS + port,
+				LAN9303_MAC_TX_CFG_X_TX_IFG_CONFIG_DEFAULT |
+				LAN9303_MAC_TX_CFG_X_TX_PAD_ENABLE |
+				LAN9303_MAC_TX_CFG_X_TX_ENABLE);
+}
+
+/* We want a special working switch:
+ * - do not forward packets between port 1 and 2
+ * - forward everything from port 1 to port 0
+ * - forward everything from port 2 to port 0
+ * - forward special tagged packets from port 0 to port 1 *or* port 2
+ */
+static int lan9303_separate_ports(struct lan9303 *chip)
+{
+	int ret;
+
+	ret = lan9303_write_switch_reg(chip, LAN9303_SWE_PORT_MIRROR,
+				LAN9303_SWE_PORT_MIRROR_SNIFFER_PORT0 |
+				LAN9303_SWE_PORT_MIRROR_MIRRORED_PORT1 |
+				LAN9303_SWE_PORT_MIRROR_MIRRORED_PORT2 |
+				LAN9303_SWE_PORT_MIRROR_ENABLE_RX_MIRRORING |
+				LAN9303_SWE_PORT_MIRROR_SNIFF_ALL);
+	if (ret)
+		return ret;
+
+	/* enable defining the destination port via special VLAN tagging
+	 * for port 0
+	 */
+	ret = lan9303_write_switch_reg(chip, LAN9303_SWE_INGRESS_PORT_TYPE,
+				       0x03);
+	if (ret)
+		return ret;
+
+	/* tag incoming packets at port 1 and 2 on their way to port 0 to be
+	 * able to discover their source port
+	 */
+	ret = lan9303_write_switch_reg(chip, LAN9303_BM_EGRSS_PORT_TYPE,
+			LAN9303_BM_EGRSS_PORT_TYPE_SPECIAL_TAG_PORT0);
+	if (ret)
+		return ret;
+
+	/* prevent port 1 and 2 from forwarding packets by their own */
+	return lan9303_write_switch_reg(chip, LAN9303_SWE_PORT_STATE,
+				LAN9303_SWE_PORT_STATE_FORWARDING_PORT0 |
+				LAN9303_SWE_PORT_STATE_BLOCKING_PORT1 |
+				LAN9303_SWE_PORT_STATE_BLOCKING_PORT2);
+}
+
+static int lan9303_handle_reset(struct lan9303 *chip)
+{
+	if (!chip->reset_gpio)
+		return 0;
+
+	if (chip->reset_duration != 0)
+		msleep(chip->reset_duration);
+
+	/* release (deassert) reset and activate the device */
+	gpiod_set_value_cansleep(chip->reset_gpio, 0);
+
+	return 0;
+}
+
+/* stop processing packets for all ports */
+static int lan9303_disable_processing(struct lan9303 *chip)
+{
+	int ret;
+
+	ret = lan9303_disable_packet_processing(chip, LAN9303_PORT_0_OFFSET);
+	if (ret)
+		return ret;
+	ret = lan9303_disable_packet_processing(chip, LAN9303_PORT_1_OFFSET);
+	if (ret)
+		return ret;
+	return lan9303_disable_packet_processing(chip, LAN9303_PORT_2_OFFSET);
+}
+
+static int lan9303_check_device(struct lan9303 *chip)
+{
+	int ret;
+	u32 reg;
+
+	ret = lan9303_read(chip->regmap, LAN9303_CHIP_REV, &reg);
+	if (ret) {
+		dev_err(chip->dev, "failed to read chip revision register: %d\n",
+			ret);
+		if (!chip->reset_gpio) {
+			dev_dbg(chip->dev,
+				"hint: maybe failed due to missing reset GPIO\n");
+		}
+		return ret;
+	}
+
+	if ((reg >> 16) != LAN9303_CHIP_ID) {
+		dev_err(chip->dev, "expecting LAN9303 chip, but found: %X\n",
+			reg >> 16);
+		return ret;
+	}
+
+	/* The default state of the LAN9303 device is to forward packets between
+	 * all ports (if not configured differently by an external EEPROM).
+	 * The initial state of a DSA device must be forwarding packets only
+	 * between the external and the internal ports and no forwarding
+	 * between the external ports. In preparation we stop packet handling
+	 * at all for now until the LAN9303 device is re-programmed accordingly.
+	 */
+	ret = lan9303_disable_processing(chip);
+	if (ret)
+		dev_warn(chip->dev, "failed to disable switching %d\n", ret);
+
+	dev_info(chip->dev, "Found LAN9303 rev. %u\n", reg & 0xffff);
+
+	ret = lan9303_detect_phy_setup(chip);
+	if (ret) {
+		dev_err(chip->dev,
+			"failed to discover phy bootstrap setup: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+/* ---------------------------- DSA -----------------------------------*/
+
+static enum dsa_tag_protocol lan9303_get_tag_protocol(struct dsa_switch *ds)
+{
+	return DSA_TAG_PROTO_LAN9303;
+}
+
+static int lan9303_setup(struct dsa_switch *ds)
+{
+	struct lan9303 *chip = ds_to_lan9303(ds);
+	int ret;
+
+	/* Make sure that port 0 is the cpu port */
+	if (!dsa_is_cpu_port(ds, 0)) {
+		dev_err(chip->dev, "port 0 is not the CPU port\n");
+		return -EINVAL;
+	}
+
+	ret = lan9303_separate_ports(chip);
+	if (ret)
+		dev_err(chip->dev, "failed to separate ports %d\n", ret);
+
+	ret = lan9303_enable_packet_processing(chip, LAN9303_PORT_0_OFFSET);
+	if (ret)
+		dev_err(chip->dev, "failed to re-enable switching %d\n", ret);
+
+	return 0;
+}
+
+struct lan9303_mib_desc {
+	unsigned int offset; /* offset of first MAC */
+	const char *name;
+};
+
+static const struct lan9303_mib_desc lan9303_mib[] = {
+	{ .offset = LAN9303_MAC_RX_BRDCST_CNT_0, .name = "RxBroad", },
+	{ .offset = LAN9303_MAC_RX_PAUSE_CNT_0, .name = "RxPause", },
+	{ .offset = LAN9303_MAC_RX_MULCST_CNT_0, .name = "RxMulti", },
+	{ .offset = LAN9303_MAC_RX_PKTOK_CNT_0, .name = "RxOk", },
+	{ .offset = LAN9303_MAC_RX_CRCERR_CNT_0, .name = "RxCrcErr", },
+	{ .offset = LAN9303_MAC_RX_ALIGN_CNT_0, .name = "RxAlignErr", },
+	{ .offset = LAN9303_MAC_RX_JABB_CNT_0, .name = "RxJabber", },
+	{ .offset = LAN9303_MAC_RX_FRAG_CNT_0, .name = "RxFragment", },
+	{ .offset = LAN9303_MAC_RX_64_CNT_0, .name = "Rx64Byte", },
+	{ .offset = LAN9303_MAC_RX_127_CNT_0, .name = "Rx128Byte", },
+	{ .offset = LAN9303_MAC_RX_255_CNT_0, .name = "Rx256Byte", },
+	{ .offset = LAN9303_MAC_RX_511_CNT_0, .name = "Rx512Byte", },
+	{ .offset = LAN9303_MAC_RX_1023_CNT_0, .name = "Rx1024Byte", },
+	{ .offset = LAN9303_MAC_RX_MAX_CNT_0, .name = "RxMaxByte", },
+	{ .offset = LAN9303_MAC_RX_PKTLEN_CNT_0, .name = "RxByteCnt", },
+	{ .offset = LAN9303_MAC_RX_SYMBL_CNT_0, .name = "RxSymbolCnt", },
+	{ .offset = LAN9303_MAC_RX_CTLFRM_CNT_0, .name = "RxCfs", },
+	{ .offset = LAN9303_MAC_RX_OVRSZE_CNT_0, .name = "RxOverFlow", },
+	{ .offset = LAN9303_MAC_TX_UNDSZE_CNT_0, .name = "TxShort", },
+	{ .offset = LAN9303_MAC_TX_BRDCST_CNT_0, .name = "TxBroad", },
+	{ .offset = LAN9303_MAC_TX_PAUSE_CNT_0, .name = "TxPause", },
+	{ .offset = LAN9303_MAC_TX_MULCST_CNT_0, .name = "TxMulti", },
+	{ .offset = LAN9303_MAC_RX_UNDSZE_CNT_0, .name = "TxUnderRun", },
+	{ .offset = LAN9303_MAC_TX_64_CNT_0, .name = "Tx64Byte", },
+	{ .offset = LAN9303_MAC_TX_127_CNT_0, .name = "Tx128Byte", },
+	{ .offset = LAN9303_MAC_TX_255_CNT_0, .name = "Tx256Byte", },
+	{ .offset = LAN9303_MAC_TX_511_CNT_0, .name = "Tx512Byte", },
+	{ .offset = LAN9303_MAC_TX_1023_CNT_0, .name = "Tx1024Byte", },
+	{ .offset = LAN9303_MAC_TX_MAX_CNT_0, .name = "TxMaxByte", },
+	{ .offset = LAN9303_MAC_TX_PKTLEN_CNT_0, .name = "TxByteCnt", },
+	{ .offset = LAN9303_MAC_TX_PKTOK_CNT_0, .name = "TxOk", },
+	{ .offset = LAN9303_MAC_TX_TOTALCOL_CNT_0, .name = "TxCollision", },
+	{ .offset = LAN9303_MAC_TX_MULTICOL_CNT_0, .name = "TxMultiCol", },
+	{ .offset = LAN9303_MAC_TX_SNGLECOL_CNT_0, .name = "TxSingleCol", },
+	{ .offset = LAN9303_MAC_TX_EXCOL_CNT_0, .name = "TxExcCol", },
+	{ .offset = LAN9303_MAC_TX_DEFER_CNT_0, .name = "TxDefer", },
+	{ .offset = LAN9303_MAC_TX_LATECOL_0, .name = "TxLateCol", },
+};
+
+static void lan9303_get_strings(struct dsa_switch *ds, int port, uint8_t *data)
+{
+	unsigned int u;
+
+	for (u = 0; u < ARRAY_SIZE(lan9303_mib); u++) {
+		strncpy(data + u * ETH_GSTRING_LEN, lan9303_mib[u].name,
+			ETH_GSTRING_LEN);
+	}
+}
+
+static void lan9303_get_ethtool_stats(struct dsa_switch *ds, int port,
+				      uint64_t *data)
+{
+	struct lan9303 *chip = ds_to_lan9303(ds);
+	u32 reg;
+	unsigned int u, poff;
+	int ret;
+
+	poff = port * 0x400;
+
+	for (u = 0; u < ARRAY_SIZE(lan9303_mib); u++) {
+		ret = lan9303_read_switch_reg(chip,
+					      lan9303_mib[u].offset + poff,
+					      &reg);
+		if (ret)
+			dev_warn(chip->dev, "Reading status reg %u failed\n",
+				 lan9303_mib[u].offset + poff);
+		data[u] = reg;
+	}
+}
+
+static int lan9303_get_sset_count(struct dsa_switch *ds)
+{
+	return ARRAY_SIZE(lan9303_mib);
+}
+
+static int lan9303_phy_read(struct dsa_switch *ds, int phy, int regnum)
+{
+	struct lan9303 *chip = ds_to_lan9303(ds);
+	int phy_base = chip->phy_addr_sel_strap;
+
+	if (phy == phy_base)
+		return lan9303_virt_phy_reg_read(chip, regnum);
+	if (phy > phy_base + 2)
+		return -ENODEV;
+
+	return lan9303_port_phy_reg_read(chip, phy, regnum);
+}
+
+static int lan9303_phy_write(struct dsa_switch *ds, int phy, int regnum,
+			     u16 val)
+{
+	struct lan9303 *chip = ds_to_lan9303(ds);
+	int phy_base = chip->phy_addr_sel_strap;
+
+	if (phy == phy_base)
+		return lan9303_virt_phy_reg_write(chip, regnum, val);
+	if (phy > phy_base + 2)
+		return -ENODEV;
+
+	return lan9303_phy_reg_write(chip, phy, regnum, val);
+}
+
+static int lan9303_port_enable(struct dsa_switch *ds, int port,
+			       struct phy_device *phy)
+{
+	struct lan9303 *chip = ds_to_lan9303(ds);
+
+	/* enable internal packet processing */
+	switch (port) {
+	case 1:
+		return lan9303_enable_packet_processing(chip,
+							LAN9303_PORT_1_OFFSET);
+	case 2:
+		return lan9303_enable_packet_processing(chip,
+							LAN9303_PORT_2_OFFSET);
+	default:
+		dev_dbg(chip->dev,
+			"Error: request to power up invalid port %d\n", port);
+	}
+
+	return -ENODEV;
+}
+
+static void lan9303_port_disable(struct dsa_switch *ds, int port,
+				 struct phy_device *phy)
+{
+	struct lan9303 *chip = ds_to_lan9303(ds);
+
+	/* disable internal packet processing */
+	switch (port) {
+	case 1:
+		lan9303_disable_packet_processing(chip, LAN9303_PORT_1_OFFSET);
+		lan9303_phy_reg_write(chip, chip->phy_addr_sel_strap + 1,
+				      MII_BMCR, BMCR_PDOWN);
+		break;
+	case 2:
+		lan9303_disable_packet_processing(chip, LAN9303_PORT_2_OFFSET);
+		lan9303_phy_reg_write(chip, chip->phy_addr_sel_strap + 2,
+				      MII_BMCR, BMCR_PDOWN);
+		break;
+	default:
+		dev_dbg(chip->dev,
+			"Error: request to power down invalid port %d\n", port);
+	}
+}
+
+static struct dsa_switch_ops lan9303_switch_ops = {
+	.get_tag_protocol = lan9303_get_tag_protocol,
+	.setup = lan9303_setup,
+	.get_strings = lan9303_get_strings,
+	.phy_read = lan9303_phy_read,
+	.phy_write = lan9303_phy_write,
+	.get_ethtool_stats = lan9303_get_ethtool_stats,
+	.get_sset_count = lan9303_get_sset_count,
+	.port_enable = lan9303_port_enable,
+	.port_disable = lan9303_port_disable,
+};
+
+static int lan9303_register_switch(struct lan9303 *chip)
+{
+	chip->ds = dsa_switch_alloc(chip->dev, DSA_MAX_PORTS);
+	if (!chip->ds)
+		return -ENOMEM;
+
+	chip->ds->priv = chip;
+	chip->ds->ops = &lan9303_switch_ops;
+	chip->ds->phys_mii_mask = chip->phy_addr_sel_strap ? 0xe : 0x7;
+
+	return dsa_register_switch(chip->ds, chip->dev);
+}
+
+static void lan9303_probe_reset_gpio(struct lan9303 *chip,
+				     struct device_node *np)
+{
+	chip->reset_gpio = devm_gpiod_get_optional(chip->dev, "reset",
+						   GPIOD_OUT_LOW);
+
+	if (!chip->reset_gpio) {
+		dev_dbg(chip->dev, "No reset GPIO defined\n");
+		return;
+	}
+
+	chip->reset_duration = 200;
+
+	if (np) {
+		of_property_read_u32(np, "reset-duration",
+				     &chip->reset_duration);
+	} else {
+		dev_dbg(chip->dev, "reset duration defaults to 200 ms\n");
+	}
+
+	/* A sane reset duration should not be longer than 1s */
+	if (chip->reset_duration > 1000)
+		chip->reset_duration = 1000;
+}
+
+int lan9303_probe(struct lan9303 *chip, struct device_node *np)
+{
+	int ret;
+
+	mutex_init(&chip->indirect_mutex);
+
+	lan9303_probe_reset_gpio(chip, np);
+
+	ret = lan9303_handle_reset(chip);
+	if (ret)
+		return ret;
+
+	ret = lan9303_check_device(chip);
+	if (ret)
+		return ret;
+
+	ret = lan9303_register_switch(chip);
+	if (ret) {
+		dev_dbg(chip->dev, "Failed to register switch: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+int lan9303_remove(struct lan9303 *chip)
+{
+	int rc;
+
+	rc = lan9303_disable_processing(chip);
+	if (rc != 0)
+		dev_warn(chip->dev, "shutting down failed\n");
+
+	dsa_unregister_switch(chip->ds);
+
+	/* assert reset to the whole device to prevent it from doing anything */
+	gpiod_set_value_cansleep(chip->reset_gpio, 1);
+	gpiod_unexport(chip->reset_gpio);
+
+	return 0;
+}
+
+MODULE_AUTHOR("Juergen Borleis <kernel@pengutronix.de>");
+MODULE_DESCRIPTION("Driver for SMSC/Microchip LAN9303 three port ethernet switch");
+MODULE_LICENSE("GPL");
diff --git a/drivers/net/dsa/lan9303.h b/drivers/net/dsa/lan9303.h
new file mode 100644
index 0000000000000..79ab7ed7483d8
--- /dev/null
+++ b/drivers/net/dsa/lan9303.h
@@ -0,0 +1,24 @@
+#include <linux/regmap.h>
+#include <linux/device.h>
+#include <net/dsa.h>
+
+struct lan9303 {
+	struct device *dev;
+	struct regmap *regmap;
+	struct regmap_irq_chip_data *irq_data;
+	struct gpio_desc *reset_gpio;
+	u32 reset_duration; /* in [ms] */
+	bool phy_addr_sel_strap;
+	struct dsa_switch *ds;
+	struct mutex indirect_mutex; /* protect indexed register access */
+};
+
+extern const struct regmap_access_table lan9303_register_set;
+
+static inline struct lan9303 *ds_to_lan9303(struct dsa_switch *ds)
+{
+	return (struct lan9303 *)ds->priv;
+}
+
+int lan9303_probe(struct lan9303 *chip, struct device_node *np);
+int lan9303_remove(struct lan9303 *chip);
-- 
2.11.0