1 files changed, 489 insertions, 0 deletions

diff --git a/drivers/net/dsa/realtek-smi.c b/drivers/net/dsa/realtek-smi.c
new file mode 100644
index 000000000000..b4b839a1d095
--- /dev/null
+++ b/drivers/net/dsa/realtek-smi.c
@@ -0,0 +1,489 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Realtek Simple Management Interface (SMI) driver
+ * It can be discussed how "simple" this interface is.
+ *
+ * The SMI protocol piggy-backs the MDIO MDC and MDIO signals levels
+ * but the protocol is not MDIO at all. Instead it is a Realtek
+ * pecularity that need to bit-bang the lines in a special way to
+ * communicate with the switch.
+ *
+ * ASICs we intend to support with this driver:
+ *
+ * RTL8366   - The original version, apparently
+ * RTL8369   - Similar enough to have the same datsheet as RTL8366
+ * RTL8366RB - Probably reads out "RTL8366 revision B", has a quite
+ *             different register layout from the other two
+ * RTL8366S  - Is this "RTL8366 super"?
+ * RTL8367   - Has an OpenWRT driver as well
+ * RTL8368S  - Seems to be an alternative name for RTL8366RB
+ * RTL8370   - Also uses SMI
+ *
+ * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
+ * Copyright (C) 2010 Antti Seppälä <a.seppala@gmail.com>
+ * Copyright (C) 2010 Roman Yeryomin <roman@advem.lv>
+ * Copyright (C) 2011 Colin Leitner <colin.leitner@googlemail.com>
+ * Copyright (C) 2009-2010 Gabor Juhos <juhosg@openwrt.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/spinlock.h>
+#include <linux/skbuff.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_mdio.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/bitops.h>
+#include <linux/if_bridge.h>
+
+#include "realtek-smi.h"
+
+#define REALTEK_SMI_ACK_RETRY_COUNT		5
+#define REALTEK_SMI_HW_STOP_DELAY		25	/* msecs */
+#define REALTEK_SMI_HW_START_DELAY		100	/* msecs */
+
+static inline void realtek_smi_clk_delay(struct realtek_smi *smi)
+{
+	ndelay(smi->clk_delay);
+}
+
+static void realtek_smi_start(struct realtek_smi *smi)
+{
+	/* Set GPIO pins to output mode, with initial state:
+	 * SCK = 0, SDA = 1
+	 */
+	gpiod_direction_output(smi->mdc, 0);
+	gpiod_direction_output(smi->mdio, 1);
+	realtek_smi_clk_delay(smi);
+
+	/* CLK 1: 0 -> 1, 1 -> 0 */
+	gpiod_set_value(smi->mdc, 1);
+	realtek_smi_clk_delay(smi);
+	gpiod_set_value(smi->mdc, 0);
+	realtek_smi_clk_delay(smi);
+
+	/* CLK 2: */
+	gpiod_set_value(smi->mdc, 1);
+	realtek_smi_clk_delay(smi);
+	gpiod_set_value(smi->mdio, 0);
+	realtek_smi_clk_delay(smi);
+	gpiod_set_value(smi->mdc, 0);
+	realtek_smi_clk_delay(smi);
+	gpiod_set_value(smi->mdio, 1);
+}
+
+static void realtek_smi_stop(struct realtek_smi *smi)
+{
+	realtek_smi_clk_delay(smi);
+	gpiod_set_value(smi->mdio, 0);
+	gpiod_set_value(smi->mdc, 1);
+	realtek_smi_clk_delay(smi);
+	gpiod_set_value(smi->mdio, 1);
+	realtek_smi_clk_delay(smi);
+	gpiod_set_value(smi->mdc, 1);
+	realtek_smi_clk_delay(smi);
+	gpiod_set_value(smi->mdc, 0);
+	realtek_smi_clk_delay(smi);
+	gpiod_set_value(smi->mdc, 1);
+
+	/* Add a click */
+	realtek_smi_clk_delay(smi);
+	gpiod_set_value(smi->mdc, 0);
+	realtek_smi_clk_delay(smi);
+	gpiod_set_value(smi->mdc, 1);
+
+	/* Set GPIO pins to input mode */
+	gpiod_direction_input(smi->mdio);
+	gpiod_direction_input(smi->mdc);
+}
+
+static void realtek_smi_write_bits(struct realtek_smi *smi, u32 data, u32 len)
+{
+	for (; len > 0; len--) {
+		realtek_smi_clk_delay(smi);
+
+		/* Prepare data */
+		gpiod_set_value(smi->mdio, !!(data & (1 << (len - 1))));
+		realtek_smi_clk_delay(smi);
+
+		/* Clocking */
+		gpiod_set_value(smi->mdc, 1);
+		realtek_smi_clk_delay(smi);
+		gpiod_set_value(smi->mdc, 0);
+	}
+}
+
+static void realtek_smi_read_bits(struct realtek_smi *smi, u32 len, u32 *data)
+{
+	gpiod_direction_input(smi->mdio);
+
+	for (*data = 0; len > 0; len--) {
+		u32 u;
+
+		realtek_smi_clk_delay(smi);
+
+		/* Clocking */
+		gpiod_set_value(smi->mdc, 1);
+		realtek_smi_clk_delay(smi);
+		u = !!gpiod_get_value(smi->mdio);
+		gpiod_set_value(smi->mdc, 0);
+
+		*data |= (u << (len - 1));
+	}
+
+	gpiod_direction_output(smi->mdio, 0);
+}
+
+static int realtek_smi_wait_for_ack(struct realtek_smi *smi)
+{
+	int retry_cnt;
+
+	retry_cnt = 0;
+	do {
+		u32 ack;
+
+		realtek_smi_read_bits(smi, 1, &ack);
+		if (ack == 0)
+			break;
+
+		if (++retry_cnt > REALTEK_SMI_ACK_RETRY_COUNT) {
+			dev_err(smi->dev, "ACK timeout\n");
+			return -ETIMEDOUT;
+		}
+	} while (1);
+
+	return 0;
+}
+
+static int realtek_smi_write_byte(struct realtek_smi *smi, u8 data)
+{
+	realtek_smi_write_bits(smi, data, 8);
+	return realtek_smi_wait_for_ack(smi);
+}
+
+static int realtek_smi_write_byte_noack(struct realtek_smi *smi, u8 data)
+{
+	realtek_smi_write_bits(smi, data, 8);
+	return 0;
+}
+
+static int realtek_smi_read_byte0(struct realtek_smi *smi, u8 *data)
+{
+	u32 t;
+
+	/* Read data */
+	realtek_smi_read_bits(smi, 8, &t);
+	*data = (t & 0xff);
+
+	/* Send an ACK */
+	realtek_smi_write_bits(smi, 0x00, 1);
+
+	return 0;
+}
+
+static int realtek_smi_read_byte1(struct realtek_smi *smi, u8 *data)
+{
+	u32 t;
+
+	/* Read data */
+	realtek_smi_read_bits(smi, 8, &t);
+	*data = (t & 0xff);
+
+	/* Send an ACK */
+	realtek_smi_write_bits(smi, 0x01, 1);
+
+	return 0;
+}
+
+static int realtek_smi_read_reg(struct realtek_smi *smi, u32 addr, u32 *data)
+{
+	unsigned long flags;
+	u8 lo = 0;
+	u8 hi = 0;
+	int ret;
+
+	spin_lock_irqsave(&smi->lock, flags);
+
+	realtek_smi_start(smi);
+
+	/* Send READ command */
+	ret = realtek_smi_write_byte(smi, smi->cmd_read);
+	if (ret)
+		goto out;
+
+	/* Set ADDR[7:0] */
+	ret = realtek_smi_write_byte(smi, addr & 0xff);
+	if (ret)
+		goto out;
+
+	/* Set ADDR[15:8] */
+	ret = realtek_smi_write_byte(smi, addr >> 8);
+	if (ret)
+		goto out;
+
+	/* Read DATA[7:0] */
+	realtek_smi_read_byte0(smi, &lo);
+	/* Read DATA[15:8] */
+	realtek_smi_read_byte1(smi, &hi);
+
+	*data = ((u32)lo) | (((u32)hi) << 8);
+
+	ret = 0;
+
+ out:
+	realtek_smi_stop(smi);
+	spin_unlock_irqrestore(&smi->lock, flags);
+
+	return ret;
+}
+
+static int realtek_smi_write_reg(struct realtek_smi *smi,
+				 u32 addr, u32 data, bool ack)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&smi->lock, flags);
+
+	realtek_smi_start(smi);
+
+	/* Send WRITE command */
+	ret = realtek_smi_write_byte(smi, smi->cmd_write);
+	if (ret)
+		goto out;
+
+	/* Set ADDR[7:0] */
+	ret = realtek_smi_write_byte(smi, addr & 0xff);
+	if (ret)
+		goto out;
+
+	/* Set ADDR[15:8] */
+	ret = realtek_smi_write_byte(smi, addr >> 8);
+	if (ret)
+		goto out;
+
+	/* Write DATA[7:0] */
+	ret = realtek_smi_write_byte(smi, data & 0xff);
+	if (ret)
+		goto out;
+
+	/* Write DATA[15:8] */
+	if (ack)
+		ret = realtek_smi_write_byte(smi, data >> 8);
+	else
+		ret = realtek_smi_write_byte_noack(smi, data >> 8);
+	if (ret)
+		goto out;
+
+	ret = 0;
+
+ out:
+	realtek_smi_stop(smi);
+	spin_unlock_irqrestore(&smi->lock, flags);
+
+	return ret;
+}
+
+/* There is one single case when we need to use this accessor and that
+ * is when issueing soft reset. Since the device reset as soon as we write
+ * that bit, no ACK will come back for natural reasons.
+ */
+int realtek_smi_write_reg_noack(struct realtek_smi *smi, u32 addr,
+				u32 data)
+{
+	return realtek_smi_write_reg(smi, addr, data, false);
+}
+EXPORT_SYMBOL_GPL(realtek_smi_write_reg_noack);
+
+/* Regmap accessors */
+
+static int realtek_smi_write(void *ctx, u32 reg, u32 val)
+{
+	struct realtek_smi *smi = ctx;
+
+	return realtek_smi_write_reg(smi, reg, val, true);
+}
+
+static int realtek_smi_read(void *ctx, u32 reg, u32 *val)
+{
+	struct realtek_smi *smi = ctx;
+
+	return realtek_smi_read_reg(smi, reg, val);
+}
+
+static const struct regmap_config realtek_smi_mdio_regmap_config = {
+	.reg_bits = 10, /* A4..A0 R4..R0 */
+	.val_bits = 16,
+	.reg_stride = 1,
+	/* PHY regs are at 0x8000 */
+	.max_register = 0xffff,
+	.reg_format_endian = REGMAP_ENDIAN_BIG,
+	.reg_read = realtek_smi_read,
+	.reg_write = realtek_smi_write,
+	.cache_type = REGCACHE_NONE,
+};
+
+static int realtek_smi_mdio_read(struct mii_bus *bus, int addr, int regnum)
+{
+	struct realtek_smi *smi = bus->priv;
+
+	return smi->ops->phy_read(smi, addr, regnum);
+}
+
+static int realtek_smi_mdio_write(struct mii_bus *bus, int addr, int regnum,
+				  u16 val)
+{
+	struct realtek_smi *smi = bus->priv;
+
+	return smi->ops->phy_write(smi, addr, regnum, val);
+}
+
+int realtek_smi_setup_mdio(struct realtek_smi *smi)
+{
+	struct device_node *mdio_np;
+	int ret;
+
+	mdio_np = of_find_compatible_node(smi->dev->of_node, NULL,
+					  "realtek,smi-mdio");
+	if (!mdio_np) {
+		dev_err(smi->dev, "no MDIO bus node\n");
+		return -ENODEV;
+	}
+
+	smi->slave_mii_bus = devm_mdiobus_alloc(smi->dev);
+	if (!smi->slave_mii_bus)
+		return -ENOMEM;
+	smi->slave_mii_bus->priv = smi;
+	smi->slave_mii_bus->name = "SMI slave MII";
+	smi->slave_mii_bus->read = realtek_smi_mdio_read;
+	smi->slave_mii_bus->write = realtek_smi_mdio_write;
+	snprintf(smi->slave_mii_bus->id, MII_BUS_ID_SIZE, "SMI-%d",
+		 smi->ds->index);
+	smi->slave_mii_bus->dev.of_node = mdio_np;
+	smi->slave_mii_bus->parent = smi->dev;
+	smi->ds->slave_mii_bus = smi->slave_mii_bus;
+
+	ret = of_mdiobus_register(smi->slave_mii_bus, mdio_np);
+	if (ret) {
+		dev_err(smi->dev, "unable to register MDIO bus %s\n",
+			smi->slave_mii_bus->id);
+		of_node_put(mdio_np);
+	}
+
+	return 0;
+}
+
+static int realtek_smi_probe(struct platform_device *pdev)
+{
+	const struct realtek_smi_variant *var;
+	struct device *dev = &pdev->dev;
+	struct realtek_smi *smi;
+	struct device_node *np;
+	int ret;
+
+	var = of_device_get_match_data(dev);
+	np = dev->of_node;
+
+	smi = devm_kzalloc(dev, sizeof(*smi), GFP_KERNEL);
+	if (!smi)
+		return -ENOMEM;
+	smi->map = devm_regmap_init(dev, NULL, smi,
+				    &realtek_smi_mdio_regmap_config);
+	if (IS_ERR(smi->map)) {
+		ret = PTR_ERR(smi->map);
+		dev_err(dev, "regmap init failed: %d\n", ret);
+		return ret;
+	}
+
+	/* Link forward and backward */
+	smi->dev = dev;
+	smi->clk_delay = var->clk_delay;
+	smi->cmd_read = var->cmd_read;
+	smi->cmd_write = var->cmd_write;
+	smi->ops = var->ops;
+
+	dev_set_drvdata(dev, smi);
+	spin_lock_init(&smi->lock);
+
+	/* TODO: if power is software controlled, set up any regulators here */
+
+	/* Assert then deassert RESET */
+	smi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(smi->reset)) {
+		dev_err(dev, "failed to get RESET GPIO\n");
+		return PTR_ERR(smi->reset);
+	}
+	msleep(REALTEK_SMI_HW_STOP_DELAY);
+	gpiod_set_value(smi->reset, 0);
+	msleep(REALTEK_SMI_HW_START_DELAY);
+	dev_info(dev, "deasserted RESET\n");
+
+	/* Fetch MDIO pins */
+	smi->mdc = devm_gpiod_get_optional(dev, "mdc", GPIOD_OUT_LOW);
+	if (IS_ERR(smi->mdc))
+		return PTR_ERR(smi->mdc);
+	smi->mdio = devm_gpiod_get_optional(dev, "mdio", GPIOD_OUT_LOW);
+	if (IS_ERR(smi->mdio))
+		return PTR_ERR(smi->mdio);
+
+	smi->leds_disabled = of_property_read_bool(np, "realtek,disable-leds");
+
+	ret = smi->ops->detect(smi);
+	if (ret) {
+		dev_err(dev, "unable to detect switch\n");
+		return ret;
+	}
+
+	smi->ds = dsa_switch_alloc(dev, smi->num_ports);
+	if (!smi->ds)
+		return -ENOMEM;
+	smi->ds->priv = smi;
+
+	smi->ds->ops = var->ds_ops;
+	ret = dsa_register_switch(smi->ds);
+	if (ret) {
+		dev_err(dev, "unable to register switch ret = %d\n", ret);
+		return ret;
+	}
+	return 0;
+}
+
+static int realtek_smi_remove(struct platform_device *pdev)
+{
+	struct realtek_smi *smi = dev_get_drvdata(&pdev->dev);
+
+	dsa_unregister_switch(smi->ds);
+	gpiod_set_value(smi->reset, 1);
+
+	return 0;
+}
+
+static const struct of_device_id realtek_smi_of_match[] = {
+	{
+		.compatible = "realtek,rtl8366rb",
+		.data = &rtl8366rb_variant,
+	},
+	{
+		/* FIXME: add support for RTL8366S and more */
+		.compatible = "realtek,rtl8366s",
+		.data = NULL,
+	},
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, realtek_smi_of_match);
+
+static struct platform_driver realtek_smi_driver = {
+	.driver = {
+		.name = "realtek-smi",
+		.of_match_table = of_match_ptr(realtek_smi_of_match),
+	},
+	.probe  = realtek_smi_probe,
+	.remove = realtek_smi_remove,
+};
+module_platform_driver(realtek_smi_driver);
+
+MODULE_LICENSE("GPL");