net: dsa: microchip: add DSA support for microchip LAN937x

Basic DSA driver support for lan937x and the device will be
configured through SPI interface.
It adds the lan937x_dev_ops in ksz_common.c file and tries to reuse the
functionality of ksz9477 series switch.

drivers/net/dsa/microchip/ path is already part of MAINTAINERS &
the new files come under this path. Hence no update needed to the
MAINTAINERS

Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 154 insertions, 0 deletions

diff --git a/drivers/net/dsa/microchip/lan937x_main.c b/drivers/net/dsa/microchip/lan937x_main.c
new file mode 100644
index 000000000000..e167a0c1ff85
--- /dev/null
+++ b/drivers/net/dsa/microchip/lan937x_main.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Microchip LAN937X switch driver main logic
+ * Copyright (C) 2019-2022 Microchip Technology Inc.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/iopoll.h>
+#include <linux/phy.h>
+#include <linux/of_net.h>
+#include <linux/if_bridge.h>
+#include <linux/math.h>
+#include <net/dsa.h>
+#include <net/switchdev.h>
+
+#include "lan937x_reg.h"
+#include "ksz_common.h"
+#include "lan937x.h"
+
+static int lan937x_cfg(struct ksz_device *dev, u32 addr, u8 bits, bool set)
+{
+	return regmap_update_bits(dev->regmap[0], addr, bits, set ? bits : 0);
+}
+
+static int lan937x_port_cfg(struct ksz_device *dev, int port, int offset,
+			    u8 bits, bool set)
+{
+	return regmap_update_bits(dev->regmap[0], PORT_CTRL_ADDR(port, offset),
+				  bits, set ? bits : 0);
+}
+
+int lan937x_reset_switch(struct ksz_device *dev)
+{
+	u32 data32;
+	int ret;
+
+	/* reset switch */
+	ret = lan937x_cfg(dev, REG_SW_OPERATION, SW_RESET, true);
+	if (ret < 0)
+		return ret;
+
+	/* Enable Auto Aging */
+	ret = lan937x_cfg(dev, REG_SW_LUE_CTRL_1, SW_LINK_AUTO_AGING, true);
+	if (ret < 0)
+		return ret;
+
+	/* disable interrupts */
+	ret = ksz_write32(dev, REG_SW_INT_MASK__4, SWITCH_INT_MASK);
+	if (ret < 0)
+		return ret;
+
+	ret = ksz_write32(dev, REG_SW_PORT_INT_MASK__4, 0xFF);
+	if (ret < 0)
+		return ret;
+
+	return ksz_read32(dev, REG_SW_PORT_INT_STATUS__4, &data32);
+}
+
+void lan937x_port_setup(struct ksz_device *dev, int port, bool cpu_port)
+{
+	struct dsa_switch *ds = dev->ds;
+	u8 member;
+
+	/* enable tag tail for host port */
+	if (cpu_port)
+		lan937x_port_cfg(dev, port, REG_PORT_CTRL_0,
+				 PORT_TAIL_TAG_ENABLE, true);
+
+	/* disable frame check length field */
+	lan937x_port_cfg(dev, port, REG_PORT_MAC_CTRL_0, PORT_CHECK_LENGTH,
+			 false);
+
+	/* set back pressure for half duplex */
+	lan937x_port_cfg(dev, port, REG_PORT_MAC_CTRL_1, PORT_BACK_PRESSURE,
+			 true);
+
+	/* enable 802.1p priority */
+	lan937x_port_cfg(dev, port, P_PRIO_CTRL, PORT_802_1P_PRIO_ENABLE, true);
+
+	if (!dev->info->internal_phy[port])
+		lan937x_port_cfg(dev, port, REG_PORT_XMII_CTRL_0,
+				 PORT_MII_TX_FLOW_CTRL | PORT_MII_RX_FLOW_CTRL,
+				 true);
+
+	if (cpu_port)
+		member = dsa_user_ports(ds);
+	else
+		member = BIT(dsa_upstream_port(ds, port));
+
+	dev->dev_ops->cfg_port_member(dev, port, member);
+}
+
+void lan937x_config_cpu_port(struct dsa_switch *ds)
+{
+	struct ksz_device *dev = ds->priv;
+	struct dsa_port *dp;
+
+	dsa_switch_for_each_cpu_port(dp, ds) {
+		if (dev->info->cpu_ports & (1 << dp->index)) {
+			dev->cpu_port = dp->index;
+
+			/* enable cpu port */
+			lan937x_port_setup(dev, dp->index, true);
+		}
+	}
+
+	dsa_switch_for_each_user_port(dp, ds) {
+		ksz_port_stp_state_set(ds, dp->index, BR_STATE_DISABLED);
+	}
+}
+
+int lan937x_setup(struct dsa_switch *ds)
+{
+	struct ksz_device *dev = ds->priv;
+
+	/* The VLAN aware is a global setting. Mixed vlan
+	 * filterings are not supported.
+	 */
+	ds->vlan_filtering_is_global = true;
+
+	/* Enable aggressive back off for half duplex & UNH mode */
+	lan937x_cfg(dev, REG_SW_MAC_CTRL_0,
+		    (SW_PAUSE_UNH_MODE | SW_NEW_BACKOFF | SW_AGGR_BACKOFF),
+		    true);
+
+	/* If NO_EXC_COLLISION_DROP bit is set, the switch will not drop
+	 * packets when 16 or more collisions occur
+	 */
+	lan937x_cfg(dev, REG_SW_MAC_CTRL_1, NO_EXC_COLLISION_DROP, true);
+
+	/* enable global MIB counter freeze function */
+	lan937x_cfg(dev, REG_SW_MAC_CTRL_6, SW_MIB_COUNTER_FREEZE, true);
+
+	/* disable CLK125 & CLK25, 1: disable, 0: enable */
+	lan937x_cfg(dev, REG_SW_GLOBAL_OUTPUT_CTRL__1,
+		    (SW_CLK125_ENB | SW_CLK25_ENB), true);
+
+	return 0;
+}
+
+int lan937x_switch_init(struct ksz_device *dev)
+{
+	dev->port_mask = (1 << dev->info->port_cnt) - 1;
+
+	return 0;
+}
+
+void lan937x_switch_exit(struct ksz_device *dev)
+{
+	lan937x_reset_switch(dev);
+}
+
+MODULE_AUTHOR("Arun Ramadoss <arun.ramadoss@microchip.com>");
+MODULE_DESCRIPTION("Microchip LAN937x Series Switch DSA Driver");
+MODULE_LICENSE("GPL");