net: dsa: add support for Atheros AR9331 built-in switch

Provide basic support for Atheros AR9331 built-in switch. So far it
works as port multiplexer without any hardware offloading support.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 869 insertions, 0 deletions

diff --git a/drivers/net/dsa/Kconfig b/drivers/net/dsa/Kconfig
index c7667645f04a..cbd74a72d0a1 100644
--- a/drivers/net/dsa/Kconfig
+++ b/drivers/net/dsa/Kconfig
@@ -54,6 +54,8 @@ source "drivers/net/dsa/mv88e6xxx/Kconfig"
 
 source "drivers/net/dsa/ocelot/Kconfig"
 
+source "drivers/net/dsa/qca/Kconfig"
+
 source "drivers/net/dsa/sja1105/Kconfig"
 
 config NET_DSA_QCA8K
diff --git a/drivers/net/dsa/Makefile b/drivers/net/dsa/Makefile
index 9d384a32b3a2..4a943ccc2ca4 100644
--- a/drivers/net/dsa/Makefile
+++ b/drivers/net/dsa/Makefile
@@ -21,4 +21,5 @@ obj-y				+= b53/
 obj-y				+= microchip/
 obj-y				+= mv88e6xxx/
 obj-y				+= ocelot/
+obj-y				+= qca/
 obj-y				+= sja1105/
diff --git a/drivers/net/dsa/qca/Kconfig b/drivers/net/dsa/qca/Kconfig
new file mode 100644
index 000000000000..e3c8d715a18f
--- /dev/null
+++ b/drivers/net/dsa/qca/Kconfig
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config NET_DSA_AR9331
+	tristate "Qualcomm Atheros AR9331 Ethernet switch support"
+	depends on NET_DSA
+	select NET_DSA_TAG_AR9331
+	select REGMAP
+	---help---
+	  This enables support for the Qualcomm Atheros AR9331 built-in Ethernet
+	  switch.
diff --git a/drivers/net/dsa/qca/Makefile b/drivers/net/dsa/qca/Makefile
new file mode 100644
index 000000000000..274022319066
--- /dev/null
+++ b/drivers/net/dsa/qca/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_NET_DSA_AR9331)	+= ar9331.o
diff --git a/drivers/net/dsa/qca/ar9331.c b/drivers/net/dsa/qca/ar9331.c
new file mode 100644
index 000000000000..0d1a7cd85fe8
--- /dev/null
+++ b/drivers/net/dsa/qca/ar9331.c
@@ -0,0 +1,855 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2019 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
+/*
+ *                   +----------------------+
+ * GMAC1----RGMII----|--MAC0                |
+ *      \---MDIO1----|--REGs                |----MDIO3----\
+ *                   |                      |             |  +------+
+ *                   |                      |             +--|      |
+ *                   |                 MAC1-|----RMII--M-----| PHY0 |-o P0
+ *                   |                      |          |  |  +------+
+ *                   |                      |          |  +--|      |
+ *                   |                 MAC2-|----RMII--------| PHY1 |-o P1
+ *                   |                      |          |  |  +------+
+ *                   |                      |          |  +--|      |
+ *                   |                 MAC3-|----RMII--------| PHY2 |-o P2
+ *                   |                      |          |  |  +------+
+ *                   |                      |          |  +--|      |
+ *                   |                 MAC4-|----RMII--------| PHY3 |-o P3
+ *                   |                      |          |  |  +------+
+ *                   |                      |          |  +--|      |
+ *                   |                 MAC5-|--+-RMII--M-----|-PHY4-|-o P4
+ *                   |                      |  |       |     +------+
+ *                   +----------------------+  |       \--CFG_SW_PHY_SWAP
+ * GMAC0---------------RMII--------------------/        \-CFG_SW_PHY_ADDR_SWAP
+ *      \---MDIO0--NC
+ *
+ * GMAC0 and MAC5 are connected together and use same PHY. Depending on
+ * configuration it can be PHY4 (default) or PHY0. Only GMAC0 or MAC5 can be
+ * used at same time. If GMAC0 is used (default) then MAC5 should be disabled.
+ *
+ * CFG_SW_PHY_SWAP - swap connections of PHY0 and PHY4. If this bit is not set
+ * PHY4 is connected to GMAC0/MAC5 bundle and PHY0 is connected to MAC1. If this
+ * bit is set, PHY4 is connected to MAC1 and PHY0 is connected to GMAC0/MAC5
+ * bundle.
+ *
+ * CFG_SW_PHY_ADDR_SWAP - swap addresses of PHY0 and PHY4
+ *
+ * CFG_SW_PHY_SWAP and CFG_SW_PHY_ADDR_SWAP are part of SoC specific register
+ * set and not related to switch internal registers.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/of_mdio.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <net/dsa.h>
+
+#define AR9331_SW_NAME				"ar9331_switch"
+#define AR9331_SW_PORTS				6
+
+/* dummy reg to change page */
+#define AR9331_SW_REG_PAGE			0x40000
+
+/* Global Interrupt */
+#define AR9331_SW_REG_GINT			0x10
+#define AR9331_SW_REG_GINT_MASK			0x14
+#define AR9331_SW_GINT_PHY_INT			BIT(2)
+
+#define AR9331_SW_REG_FLOOD_MASK		0x2c
+#define AR9331_SW_FLOOD_MASK_BROAD_TO_CPU	BIT(26)
+
+#define AR9331_SW_REG_GLOBAL_CTRL		0x30
+#define AR9331_SW_GLOBAL_CTRL_MFS_M		GENMASK(13, 0)
+
+#define AR9331_SW_REG_MDIO_CTRL			0x98
+#define AR9331_SW_MDIO_CTRL_BUSY		BIT(31)
+#define AR9331_SW_MDIO_CTRL_MASTER_EN		BIT(30)
+#define AR9331_SW_MDIO_CTRL_CMD_READ		BIT(27)
+#define AR9331_SW_MDIO_CTRL_PHY_ADDR_M		GENMASK(25, 21)
+#define AR9331_SW_MDIO_CTRL_REG_ADDR_M		GENMASK(20, 16)
+#define AR9331_SW_MDIO_CTRL_DATA_M		GENMASK(16, 0)
+
+#define AR9331_SW_REG_PORT_STATUS(_port)	(0x100 + (_port) * 0x100)
+
+/* FLOW_LINK_EN - enable mac flow control config auto-neg with phy.
+ * If not set, mac can be config by software.
+ */
+#define AR9331_SW_PORT_STATUS_FLOW_LINK_EN	BIT(12)
+
+/* LINK_EN - If set, MAC is configured from PHY link status.
+ * If not set, MAC should be configured by software.
+ */
+#define AR9331_SW_PORT_STATUS_LINK_EN		BIT(9)
+#define AR9331_SW_PORT_STATUS_DUPLEX_MODE	BIT(6)
+#define AR9331_SW_PORT_STATUS_RX_FLOW_EN	BIT(5)
+#define AR9331_SW_PORT_STATUS_TX_FLOW_EN	BIT(4)
+#define AR9331_SW_PORT_STATUS_RXMAC		BIT(3)
+#define AR9331_SW_PORT_STATUS_TXMAC		BIT(2)
+#define AR9331_SW_PORT_STATUS_SPEED_M		GENMASK(1, 0)
+#define AR9331_SW_PORT_STATUS_SPEED_1000	2
+#define AR9331_SW_PORT_STATUS_SPEED_100		1
+#define AR9331_SW_PORT_STATUS_SPEED_10		0
+
+#define AR9331_SW_PORT_STATUS_MAC_MASK \
+	(AR9331_SW_PORT_STATUS_TXMAC | AR9331_SW_PORT_STATUS_RXMAC)
+
+#define AR9331_SW_PORT_STATUS_LINK_MASK \
+	(AR9331_SW_PORT_STATUS_LINK_EN | AR9331_SW_PORT_STATUS_FLOW_LINK_EN | \
+	 AR9331_SW_PORT_STATUS_DUPLEX_MODE | \
+	 AR9331_SW_PORT_STATUS_RX_FLOW_EN | AR9331_SW_PORT_STATUS_TX_FLOW_EN | \
+	 AR9331_SW_PORT_STATUS_SPEED_M)
+
+/* Phy bypass mode
+ * ------------------------------------------------------------------------
+ * Bit:   | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 |11 |12 |13 |14 |15 |
+ *
+ * real   | start |   OP  | PhyAddr           |  Reg Addr         |  TA   |
+ * atheros| start |   OP  | 2'b00 |PhyAdd[2:0]|  Reg Addr[4:0]    |  TA   |
+ *
+ *
+ * Bit:   |16 |17 |18 |19 |20 |21 |22 |23 |24 |25 |26 |27 |28 |29 |30 |31 |
+ * real   |  Data                                                         |
+ * atheros|  Data                                                         |
+ *
+ * ------------------------------------------------------------------------
+ * Page address mode
+ * ------------------------------------------------------------------------
+ * Bit:   | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 |11 |12 |13 |14 |15 |
+ * real   | start |   OP  | PhyAddr           |  Reg Addr         |  TA   |
+ * atheros| start |   OP  | 2'b11 |                          8'b0 |  TA   |
+ *
+ * Bit:   |16 |17 |18 |19 |20 |21 |22 |23 |24 |25 |26 |27 |28 |29 |30 |31 |
+ * real   |  Data                                                         |
+ * atheros|                       | Page [9:0]                            |
+ */
+/* In case of Page Address mode, Bit[18:9] of 32 bit register address should be
+ * written to bits[9:0] of mdio data register.
+ */
+#define AR9331_SW_ADDR_PAGE			GENMASK(18, 9)
+
+/* ------------------------------------------------------------------------
+ * Normal register access mode
+ * ------------------------------------------------------------------------
+ * Bit:   | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 |11 |12 |13 |14 |15 |
+ * real   | start |   OP  | PhyAddr           |  Reg Addr         |  TA   |
+ * atheros| start |   OP  | 2'b10 |  low_addr[7:0]                |  TA   |
+ *
+ * Bit:   |16 |17 |18 |19 |20 |21 |22 |23 |24 |25 |26 |27 |28 |29 |30 |31 |
+ * real   |  Data                                                         |
+ * atheros|  Data                                                         |
+ * ------------------------------------------------------------------------
+ */
+#define AR9331_SW_LOW_ADDR_PHY			GENMASK(8, 6)
+#define AR9331_SW_LOW_ADDR_REG			GENMASK(5, 1)
+
+#define AR9331_SW_MDIO_PHY_MODE_M		GENMASK(4, 3)
+#define AR9331_SW_MDIO_PHY_MODE_PAGE		3
+#define AR9331_SW_MDIO_PHY_MODE_REG		2
+#define AR9331_SW_MDIO_PHY_MODE_BYPASS		0
+#define AR9331_SW_MDIO_PHY_ADDR_M		GENMASK(2, 0)
+
+/* Empirical determined values */
+#define AR9331_SW_MDIO_POLL_SLEEP_US		1
+#define AR9331_SW_MDIO_POLL_TIMEOUT_US		20
+
+struct ar9331_sw_priv {
+	struct device *dev;
+	struct dsa_switch ds;
+	struct dsa_switch_ops ops;
+	struct irq_domain *irqdomain;
+	struct mii_bus *mbus; /* mdio master */
+	struct mii_bus *sbus; /* mdio slave */
+	struct regmap *regmap;
+	struct reset_control *sw_reset;
+};
+
+/* Warning: switch reset will reset last AR9331_SW_MDIO_PHY_MODE_PAGE request
+ * If some kind of optimization is used, the request should be repeated.
+ */
+static int ar9331_sw_reset(struct ar9331_sw_priv *priv)
+{
+	int ret;
+
+	ret = reset_control_assert(priv->sw_reset);
+	if (ret)
+		goto error;
+
+	/* AR9331 doc do not provide any information about proper reset
+	 * sequence. The AR8136 (the closes switch to the AR9331) doc says:
+	 * reset duration should be greater than 10ms. So, let's use this value
+	 * for now.
+	 */
+	usleep_range(10000, 15000);
+	ret = reset_control_deassert(priv->sw_reset);
+	if (ret)
+		goto error;
+	/* There is no information on how long should we wait after reset.
+	 * AR8136 has an EEPROM and there is an Interrupt for EEPROM load
+	 * status. AR9331 has no EEPROM support.
+	 * For now, do not wait. In case AR8136 will be needed, the after
+	 * reset delay can be added as well.
+	 */
+
+	return 0;
+error:
+	dev_err_ratelimited(priv->dev, "%s: %i\n", __func__, ret);
+	return ret;
+}
+
+static int ar9331_sw_mbus_write(struct mii_bus *mbus, int port, int regnum,
+				u16 data)
+{
+	struct ar9331_sw_priv *priv = mbus->priv;
+	struct regmap *regmap = priv->regmap;
+	u32 val;
+	int ret;
+
+	ret = regmap_write(regmap, AR9331_SW_REG_MDIO_CTRL,
+			   AR9331_SW_MDIO_CTRL_BUSY |
+			   AR9331_SW_MDIO_CTRL_MASTER_EN |
+			   FIELD_PREP(AR9331_SW_MDIO_CTRL_PHY_ADDR_M, port) |
+			   FIELD_PREP(AR9331_SW_MDIO_CTRL_REG_ADDR_M, regnum) |
+			   FIELD_PREP(AR9331_SW_MDIO_CTRL_DATA_M, data));
+	if (ret)
+		goto error;
+
+	ret = regmap_read_poll_timeout(regmap, AR9331_SW_REG_MDIO_CTRL, val,
+				       !(val & AR9331_SW_MDIO_CTRL_BUSY),
+				       AR9331_SW_MDIO_POLL_SLEEP_US,
+				       AR9331_SW_MDIO_POLL_TIMEOUT_US);
+	if (ret)
+		goto error;
+
+	return 0;
+error:
+	dev_err_ratelimited(priv->dev, "PHY write error: %i\n", ret);
+	return ret;
+}
+
+static int ar9331_sw_mbus_read(struct mii_bus *mbus, int port, int regnum)
+{
+	struct ar9331_sw_priv *priv = mbus->priv;
+	struct regmap *regmap = priv->regmap;
+	u32 val;
+	int ret;
+
+	ret = regmap_write(regmap, AR9331_SW_REG_MDIO_CTRL,
+			   AR9331_SW_MDIO_CTRL_BUSY |
+			   AR9331_SW_MDIO_CTRL_MASTER_EN |
+			   AR9331_SW_MDIO_CTRL_CMD_READ |
+			   FIELD_PREP(AR9331_SW_MDIO_CTRL_PHY_ADDR_M, port) |
+			   FIELD_PREP(AR9331_SW_MDIO_CTRL_REG_ADDR_M, regnum));
+	if (ret)
+		goto error;
+
+	ret = regmap_read_poll_timeout(regmap, AR9331_SW_REG_MDIO_CTRL, val,
+				       !(val & AR9331_SW_MDIO_CTRL_BUSY),
+				       AR9331_SW_MDIO_POLL_SLEEP_US,
+				       AR9331_SW_MDIO_POLL_TIMEOUT_US);
+	if (ret)
+		goto error;
+
+	ret = regmap_read(regmap, AR9331_SW_REG_MDIO_CTRL, &val);
+	if (ret)
+		goto error;
+
+	return FIELD_GET(AR9331_SW_MDIO_CTRL_DATA_M, val);
+
+error:
+	dev_err_ratelimited(priv->dev, "PHY read error: %i\n", ret);
+	return ret;
+}
+
+static int ar9331_sw_mbus_init(struct ar9331_sw_priv *priv)
+{
+	struct device *dev = priv->dev;
+	static struct mii_bus *mbus;
+	struct device_node *np, *mnp;
+	int ret;
+
+	np = dev->of_node;
+
+	mbus = devm_mdiobus_alloc(dev);
+	if (!mbus)
+		return -ENOMEM;
+
+	mbus->name = np->full_name;
+	snprintf(mbus->id, MII_BUS_ID_SIZE, "%pOF", np);
+
+	mbus->read = ar9331_sw_mbus_read;
+	mbus->write = ar9331_sw_mbus_write;
+	mbus->priv = priv;
+	mbus->parent = dev;
+
+	mnp = of_get_child_by_name(np, "mdio");
+	if (!mnp)
+		return -ENODEV;
+
+	ret = of_mdiobus_register(mbus, mnp);
+	of_node_put(mnp);
+	if (ret)
+		return ret;
+
+	priv->mbus = mbus;
+
+	return 0;
+}
+
+static int ar9331_sw_setup(struct dsa_switch *ds)
+{
+	struct ar9331_sw_priv *priv = (struct ar9331_sw_priv *)ds->priv;
+	struct regmap *regmap = priv->regmap;
+	int ret;
+
+	ret = ar9331_sw_reset(priv);
+	if (ret)
+		return ret;
+
+	/* Reset will set proper defaults. CPU - Port0 will be enabled and
+	 * configured. All other ports (ports 1 - 5) are disabled
+	 */
+	ret = ar9331_sw_mbus_init(priv);
+	if (ret)
+		return ret;
+
+	/* Do not drop broadcast frames */
+	ret = regmap_write_bits(regmap, AR9331_SW_REG_FLOOD_MASK,
+				AR9331_SW_FLOOD_MASK_BROAD_TO_CPU,
+				AR9331_SW_FLOOD_MASK_BROAD_TO_CPU);
+	if (ret)
+		goto error;
+
+	/* Set max frame size to the maximum supported value */
+	ret = regmap_write_bits(regmap, AR9331_SW_REG_GLOBAL_CTRL,
+				AR9331_SW_GLOBAL_CTRL_MFS_M,
+				AR9331_SW_GLOBAL_CTRL_MFS_M);
+	if (ret)
+		goto error;
+
+	return 0;
+error:
+	dev_err_ratelimited(priv->dev, "%s: %i\n", __func__, ret);
+	return ret;
+}
+
+static void ar9331_sw_port_disable(struct dsa_switch *ds, int port)
+{
+	struct ar9331_sw_priv *priv = (struct ar9331_sw_priv *)ds->priv;
+	struct regmap *regmap = priv->regmap;
+	int ret;
+
+	ret = regmap_write(regmap, AR9331_SW_REG_PORT_STATUS(port), 0);
+	if (ret)
+		dev_err_ratelimited(priv->dev, "%s: %i\n", __func__, ret);
+}
+
+static enum dsa_tag_protocol ar9331_sw_get_tag_protocol(struct dsa_switch *ds,
+							int port)
+{
+	return DSA_TAG_PROTO_AR9331;
+}
+
+static void ar9331_sw_phylink_validate(struct dsa_switch *ds, int port,
+				       unsigned long *supported,
+				       struct phylink_link_state *state)
+{
+	__ETHTOOL_DECLARE_LINK_MODE_MASK(mask) = { 0, };
+
+	switch (port) {
+	case 0:
+		if (state->interface != PHY_INTERFACE_MODE_GMII)
+			goto unsupported;
+
+		phylink_set(mask, 1000baseT_Full);
+		phylink_set(mask, 1000baseT_Half);
+		break;
+	case 1:
+	case 2:
+	case 3:
+	case 4:
+	case 5:
+		if (state->interface != PHY_INTERFACE_MODE_INTERNAL)
+			goto unsupported;
+		break;
+	default:
+		bitmap_zero(supported, __ETHTOOL_LINK_MODE_MASK_NBITS);
+		dev_err(ds->dev, "Unsupported port: %i\n", port);
+		return;
+	}
+
+	phylink_set_port_modes(mask);
+	phylink_set(mask, Pause);
+	phylink_set(mask, Asym_Pause);
+
+	phylink_set(mask, 10baseT_Half);
+	phylink_set(mask, 10baseT_Full);
+	phylink_set(mask, 100baseT_Half);
+	phylink_set(mask, 100baseT_Full);
+
+	bitmap_and(supported, supported, mask,
+		   __ETHTOOL_LINK_MODE_MASK_NBITS);
+	bitmap_and(state->advertising, state->advertising, mask,
+		   __ETHTOOL_LINK_MODE_MASK_NBITS);
+
+	return;
+
+unsupported:
+	bitmap_zero(supported, __ETHTOOL_LINK_MODE_MASK_NBITS);
+	dev_err(ds->dev, "Unsupported interface: %d, port: %d\n",
+		state->interface, port);
+}
+
+static void ar9331_sw_phylink_mac_config(struct dsa_switch *ds, int port,
+					 unsigned int mode,
+					 const struct phylink_link_state *state)
+{
+	struct ar9331_sw_priv *priv = (struct ar9331_sw_priv *)ds->priv;
+	struct regmap *regmap = priv->regmap;
+	int ret;
+	u32 val;
+
+	switch (state->speed) {
+	case SPEED_1000:
+		val = AR9331_SW_PORT_STATUS_SPEED_1000;
+		break;
+	case SPEED_100:
+		val = AR9331_SW_PORT_STATUS_SPEED_100;
+		break;
+	case SPEED_10:
+		val = AR9331_SW_PORT_STATUS_SPEED_10;
+		break;
+	default:
+		return;
+	}
+
+	if (state->duplex)
+		val |= AR9331_SW_PORT_STATUS_DUPLEX_MODE;
+
+	if (state->pause & MLO_PAUSE_TX)
+		val |= AR9331_SW_PORT_STATUS_TX_FLOW_EN;
+
+	if (state->pause & MLO_PAUSE_RX)
+		val |= AR9331_SW_PORT_STATUS_RX_FLOW_EN;
+
+	ret = regmap_update_bits(regmap, AR9331_SW_REG_PORT_STATUS(port),
+				 AR9331_SW_PORT_STATUS_LINK_MASK, val);
+	if (ret)
+		dev_err_ratelimited(priv->dev, "%s: %i\n", __func__, ret);
+}
+
+static void ar9331_sw_phylink_mac_link_down(struct dsa_switch *ds, int port,
+					    unsigned int mode,
+					    phy_interface_t interface)
+{
+	struct ar9331_sw_priv *priv = (struct ar9331_sw_priv *)ds->priv;
+	struct regmap *regmap = priv->regmap;
+	int ret;
+
+	ret = regmap_update_bits(regmap, AR9331_SW_REG_PORT_STATUS(port),
+				 AR9331_SW_PORT_STATUS_MAC_MASK, 0);
+	if (ret)
+		dev_err_ratelimited(priv->dev, "%s: %i\n", __func__, ret);
+}
+
+static void ar9331_sw_phylink_mac_link_up(struct dsa_switch *ds, int port,
+					  unsigned int mode,
+					  phy_interface_t interface,
+					  struct phy_device *phydev)
+{
+	struct ar9331_sw_priv *priv = (struct ar9331_sw_priv *)ds->priv;
+	struct regmap *regmap = priv->regmap;
+	int ret;
+
+	ret = regmap_update_bits(regmap, AR9331_SW_REG_PORT_STATUS(port),
+				 AR9331_SW_PORT_STATUS_MAC_MASK,
+				 AR9331_SW_PORT_STATUS_MAC_MASK);
+	if (ret)
+		dev_err_ratelimited(priv->dev, "%s: %i\n", __func__, ret);
+}
+
+static const struct dsa_switch_ops ar9331_sw_ops = {
+	.get_tag_protocol	= ar9331_sw_get_tag_protocol,
+	.setup			= ar9331_sw_setup,
+	.port_disable		= ar9331_sw_port_disable,
+	.phylink_validate	= ar9331_sw_phylink_validate,
+	.phylink_mac_config	= ar9331_sw_phylink_mac_config,
+	.phylink_mac_link_down	= ar9331_sw_phylink_mac_link_down,
+	.phylink_mac_link_up	= ar9331_sw_phylink_mac_link_up,
+};
+
+static irqreturn_t ar9331_sw_irq(int irq, void *data)
+{
+	struct ar9331_sw_priv *priv = data;
+	struct regmap *regmap = priv->regmap;
+	u32 stat;
+	int ret;
+
+	ret = regmap_read(regmap, AR9331_SW_REG_GINT, &stat);
+	if (ret) {
+		dev_err(priv->dev, "can't read interrupt status\n");
+		return IRQ_NONE;
+	}
+
+	if (!stat)
+		return IRQ_NONE;
+
+	if (stat & AR9331_SW_GINT_PHY_INT) {
+		int child_irq;
+
+		child_irq = irq_find_mapping(priv->irqdomain, 0);
+		handle_nested_irq(child_irq);
+	}
+
+	ret = regmap_write(regmap, AR9331_SW_REG_GINT, stat);
+	if (ret) {
+		dev_err(priv->dev, "can't write interrupt status\n");
+		return IRQ_NONE;
+	}
+
+	return IRQ_HANDLED;
+}
+
+static void ar9331_sw_mask_irq(struct irq_data *d)
+{
+	struct ar9331_sw_priv *priv = irq_data_get_irq_chip_data(d);
+	struct regmap *regmap = priv->regmap;
+	int ret;
+
+	ret = regmap_update_bits(regmap, AR9331_SW_REG_GINT_MASK,
+				 AR9331_SW_GINT_PHY_INT, 0);
+	if (ret)
+		dev_err(priv->dev, "could not mask IRQ\n");
+}
+
+static void ar9331_sw_unmask_irq(struct irq_data *d)
+{
+	struct ar9331_sw_priv *priv = irq_data_get_irq_chip_data(d);
+	struct regmap *regmap = priv->regmap;
+	int ret;
+
+	ret = regmap_update_bits(regmap, AR9331_SW_REG_GINT_MASK,
+				 AR9331_SW_GINT_PHY_INT,
+				 AR9331_SW_GINT_PHY_INT);
+	if (ret)
+		dev_err(priv->dev, "could not unmask IRQ\n");
+}
+
+static struct irq_chip ar9331_sw_irq_chip = {
+	.name = AR9331_SW_NAME,
+	.irq_mask = ar9331_sw_mask_irq,
+	.irq_unmask = ar9331_sw_unmask_irq,
+};
+
+static int ar9331_sw_irq_map(struct irq_domain *domain, unsigned int irq,
+			     irq_hw_number_t hwirq)
+{
+	irq_set_chip_data(irq, domain->host_data);
+	irq_set_chip_and_handler(irq, &ar9331_sw_irq_chip, handle_simple_irq);
+	irq_set_nested_thread(irq, 1);
+	irq_set_noprobe(irq);
+
+	return 0;
+}
+
+static void ar9331_sw_irq_unmap(struct irq_domain *d, unsigned int irq)
+{
+	irq_set_nested_thread(irq, 0);
+	irq_set_chip_and_handler(irq, NULL, NULL);
+	irq_set_chip_data(irq, NULL);
+}
+
+static const struct irq_domain_ops ar9331_sw_irqdomain_ops = {
+	.map = ar9331_sw_irq_map,
+	.unmap = ar9331_sw_irq_unmap,
+	.xlate = irq_domain_xlate_onecell,
+};
+
+static int ar9331_sw_irq_init(struct ar9331_sw_priv *priv)
+{
+	struct device_node *np = priv->dev->of_node;
+	struct device *dev = priv->dev;
+	int ret, irq;
+
+	irq = of_irq_get(np, 0);
+	if (irq <= 0) {
+		dev_err(dev, "failed to get parent IRQ\n");
+		return irq ? irq : -EINVAL;
+	}
+
+	ret = devm_request_threaded_irq(dev, irq, NULL, ar9331_sw_irq,
+					IRQF_ONESHOT, AR9331_SW_NAME, priv);
+	if (ret) {
+		dev_err(dev, "unable to request irq: %d\n", ret);
+		return ret;
+	}
+
+	priv->irqdomain = irq_domain_add_linear(np, 1, &ar9331_sw_irqdomain_ops,
+						priv);
+	if (!priv->irqdomain) {
+		dev_err(dev, "failed to create IRQ domain\n");
+		return -EINVAL;
+	}
+
+	irq_set_parent(irq_create_mapping(priv->irqdomain, 0), irq);
+
+	return 0;
+}
+
+static int __ar9331_mdio_write(struct mii_bus *sbus, u8 mode, u16 reg, u16 val)
+{
+	u8 r, p;
+
+	p = FIELD_PREP(AR9331_SW_MDIO_PHY_MODE_M, mode) |
+		FIELD_GET(AR9331_SW_LOW_ADDR_PHY, reg);
+	r = FIELD_GET(AR9331_SW_LOW_ADDR_REG, reg);
+
+	return mdiobus_write(sbus, p, r, val);
+}
+
+static int __ar9331_mdio_read(struct mii_bus *sbus, u16 reg)
+{
+	u8 r, p;
+
+	p = FIELD_PREP(AR9331_SW_MDIO_PHY_MODE_M, AR9331_SW_MDIO_PHY_MODE_REG) |
+		FIELD_GET(AR9331_SW_LOW_ADDR_PHY, reg);
+	r = FIELD_GET(AR9331_SW_LOW_ADDR_REG, reg);
+
+	return mdiobus_read(sbus, p, r);
+}
+
+static int ar9331_mdio_read(void *ctx, const void *reg_buf, size_t reg_len,
+			    void *val_buf, size_t val_len)
+{
+	struct ar9331_sw_priv *priv = ctx;
+	struct mii_bus *sbus = priv->sbus;
+	u32 reg = *(u32 *)reg_buf;
+	int ret;
+
+	if (reg == AR9331_SW_REG_PAGE) {
+		/* We cannot read the page selector register from hardware and
+		 * we cache its value in regmap. Return all bits set here,
+		 * that regmap will always write the page on first use.
+		 */
+		*(u32 *)val_buf = GENMASK(9, 0);
+		return 0;
+	}
+
+	ret = __ar9331_mdio_read(sbus, reg);
+	if (ret < 0)
+		goto error;
+
+	*(u32 *)val_buf = ret;
+	ret = __ar9331_mdio_read(sbus, reg + 2);
+	if (ret < 0)
+		goto error;
+
+	*(u32 *)val_buf |= ret << 16;
+
+	return 0;
+error:
+	dev_err_ratelimited(&sbus->dev, "Bus error. Failed to read register.\n");
+	return ret;
+}
+
+static int ar9331_mdio_write(void *ctx, u32 reg, u32 val)
+{
+	struct ar9331_sw_priv *priv = (struct ar9331_sw_priv *)ctx;
+	struct mii_bus *sbus = priv->sbus;
+	int ret;
+
+	if (reg == AR9331_SW_REG_PAGE) {
+		ret = __ar9331_mdio_write(sbus, AR9331_SW_MDIO_PHY_MODE_PAGE,
+					  0, val);
+		if (ret < 0)
+			goto error;
+
+		return 0;
+	}
+
+	ret = __ar9331_mdio_write(sbus, AR9331_SW_MDIO_PHY_MODE_REG, reg, val);
+	if (ret < 0)
+		goto error;
+
+	ret = __ar9331_mdio_write(sbus, AR9331_SW_MDIO_PHY_MODE_REG, reg + 2,
+				  val >> 16);
+	if (ret < 0)
+		goto error;
+
+	return 0;
+error:
+	dev_err_ratelimited(&sbus->dev, "Bus error. Failed to write register.\n");
+	return ret;
+}
+
+static int ar9331_sw_bus_write(void *context, const void *data, size_t count)
+{
+	u32 reg = *(u32 *)data;
+	u32 val = *((u32 *)data + 1);
+
+	return ar9331_mdio_write(context, reg, val);
+}
+
+static const struct regmap_range ar9331_valid_regs[] = {
+	regmap_reg_range(0x0, 0x0),
+	regmap_reg_range(0x10, 0x14),
+	regmap_reg_range(0x20, 0x24),
+	regmap_reg_range(0x2c, 0x30),
+	regmap_reg_range(0x40, 0x44),
+	regmap_reg_range(0x50, 0x78),
+	regmap_reg_range(0x80, 0x98),
+
+	regmap_reg_range(0x100, 0x120),
+	regmap_reg_range(0x200, 0x220),
+	regmap_reg_range(0x300, 0x320),
+	regmap_reg_range(0x400, 0x420),
+	regmap_reg_range(0x500, 0x520),
+	regmap_reg_range(0x600, 0x620),
+
+	regmap_reg_range(0x20000, 0x200a4),
+	regmap_reg_range(0x20100, 0x201a4),
+	regmap_reg_range(0x20200, 0x202a4),
+	regmap_reg_range(0x20300, 0x203a4),
+	regmap_reg_range(0x20400, 0x204a4),
+	regmap_reg_range(0x20500, 0x205a4),
+
+	/* dummy page selector reg */
+	regmap_reg_range(AR9331_SW_REG_PAGE, AR9331_SW_REG_PAGE),
+};
+
+static const struct regmap_range ar9331_nonvolatile_regs[] = {
+	regmap_reg_range(AR9331_SW_REG_PAGE, AR9331_SW_REG_PAGE),
+};
+
+static const struct regmap_range_cfg ar9331_regmap_range[] = {
+	{
+		.selector_reg = AR9331_SW_REG_PAGE,
+		.selector_mask = GENMASK(9, 0),
+		.selector_shift = 0,
+
+		.window_start = 0,
+		.window_len = 512,
+
+		.range_min = 0,
+		.range_max = AR9331_SW_REG_PAGE - 4,
+	},
+};
+
+static const struct regmap_access_table ar9331_register_set = {
+	.yes_ranges = ar9331_valid_regs,
+	.n_yes_ranges = ARRAY_SIZE(ar9331_valid_regs),
+};
+
+static const struct regmap_access_table ar9331_volatile_set = {
+	.no_ranges = ar9331_nonvolatile_regs,
+	.n_no_ranges = ARRAY_SIZE(ar9331_nonvolatile_regs),
+};
+
+static const struct regmap_config ar9331_mdio_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = AR9331_SW_REG_PAGE,
+
+	.ranges = ar9331_regmap_range,
+	.num_ranges = ARRAY_SIZE(ar9331_regmap_range),
+
+	.volatile_table = &ar9331_volatile_set,
+	.wr_table = &ar9331_register_set,
+	.rd_table = &ar9331_register_set,
+
+	.cache_type = REGCACHE_RBTREE,
+};
+
+static struct regmap_bus ar9331_sw_bus = {
+	.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
+	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
+	.read = ar9331_mdio_read,
+	.write = ar9331_sw_bus_write,
+	.max_raw_read = 4,
+	.max_raw_write = 4,
+};
+
+static int ar9331_sw_probe(struct mdio_device *mdiodev)
+{
+	struct ar9331_sw_priv *priv;
+	struct dsa_switch *ds;
+	int ret;
+
+	priv = devm_kzalloc(&mdiodev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->regmap = devm_regmap_init(&mdiodev->dev, &ar9331_sw_bus, priv,
+					&ar9331_mdio_regmap_config);
+	if (IS_ERR(priv->regmap)) {
+		ret = PTR_ERR(priv->regmap);
+		dev_err(&mdiodev->dev, "regmap init failed: %d\n", ret);
+		return ret;
+	}
+
+	priv->sw_reset = devm_reset_control_get(&mdiodev->dev, "switch");
+	if (IS_ERR(priv->sw_reset)) {
+		dev_err(&mdiodev->dev, "missing switch reset\n");
+		return PTR_ERR(priv->sw_reset);
+	}
+
+	priv->sbus = mdiodev->bus;
+	priv->dev = &mdiodev->dev;
+
+	ret = ar9331_sw_irq_init(priv);
+	if (ret)
+		return ret;
+
+	ds = &priv->ds;
+	ds->dev = &mdiodev->dev;
+	ds->num_ports = AR9331_SW_PORTS;
+	ds->priv = priv;
+	priv->ops = ar9331_sw_ops;
+	ds->ops = &priv->ops;
+	dev_set_drvdata(&mdiodev->dev, priv);
+
+	ret = dsa_register_switch(ds);
+	if (ret)
+		goto err_remove_irq;
+
+	return 0;
+
+err_remove_irq:
+	irq_domain_remove(priv->irqdomain);
+
+	return ret;
+}
+
+static void ar9331_sw_remove(struct mdio_device *mdiodev)
+{
+	struct ar9331_sw_priv *priv = dev_get_drvdata(&mdiodev->dev);
+
+	irq_domain_remove(priv->irqdomain);
+	mdiobus_unregister(priv->mbus);
+	dsa_unregister_switch(&priv->ds);
+
+	reset_control_assert(priv->sw_reset);
+}
+
+static const struct of_device_id ar9331_sw_of_match[] = {
+	{ .compatible = "qca,ar9331-switch" },
+	{ },
+};
+
+static struct mdio_driver ar9331_sw_mdio_driver = {
+	.probe = ar9331_sw_probe,
+	.remove = ar9331_sw_remove,
+	.mdiodrv.driver = {
+		.name = AR9331_SW_NAME,
+		.of_match_table = ar9331_sw_of_match,
+	},
+};
+
+mdio_module_driver(ar9331_sw_mdio_driver);
+
+MODULE_AUTHOR("Oleksij Rempel <kernel@pengutronix.de>");
+MODULE_DESCRIPTION("Driver for Atheros AR9331 switch");
+MODULE_LICENSE("GPL v2");