// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2022 Schneider Electric
 *
 * Clément Léger <clement.leger@bootlin.com>
 */

#include <linux/clk.h>
#include <linux/device.h>
#include <linux/mdio.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/pcs-rzn1-miic.h>
#include <linux/phylink.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <dt-bindings/net/pcs-rzn1-miic.h>

#define MIIC_PRCMD			0x0
#define MIIC_ESID_CODE			0x4

#define MIIC_MODCTRL			0x20
#define MIIC_MODCTRL_SW_MODE		GENMASK(4, 0)

#define MIIC_CONVCTRL(port)		(0x100 + (port) * 4)

#define MIIC_CONVCTRL_CONV_SPEED	GENMASK(1, 0)
#define CONV_MODE_10MBPS		0
#define CONV_MODE_100MBPS		1
#define CONV_MODE_1000MBPS		2

#define MIIC_CONVCTRL_CONV_MODE		GENMASK(3, 2)
#define CONV_MODE_MII			0
#define CONV_MODE_RMII			1
#define CONV_MODE_RGMII			2

#define MIIC_CONVCTRL_FULLD		BIT(8)
#define MIIC_CONVCTRL_RGMII_LINK	BIT(12)
#define MIIC_CONVCTRL_RGMII_DUPLEX	BIT(13)
#define MIIC_CONVCTRL_RGMII_SPEED	GENMASK(15, 14)

#define MIIC_CONVRST			0x114
#define MIIC_CONVRST_PHYIF_RST(port)	BIT(port)
#define MIIC_CONVRST_PHYIF_RST_MASK	GENMASK(4, 0)

#define MIIC_SWCTRL			0x304
#define MIIC_SWDUPC			0x308

#define MIIC_MAX_NR_PORTS		5

#define MIIC_MODCTRL_CONF_CONV_NUM	6
#define MIIC_MODCTRL_CONF_NONE		-1

/**
 * struct modctrl_match - Matching table entry for  convctrl configuration
 *			  See section 8.2.1 of manual.
 * @mode_cfg: Configuration value for convctrl
 * @conv: Configuration of ethernet port muxes. First index is SWITCH_PORTIN,
 *	  then index 1 - 5 are CONV1 - CONV5.
 */
struct modctrl_match {
	u32 mode_cfg;
	u8 conv[MIIC_MODCTRL_CONF_CONV_NUM];
};

static struct modctrl_match modctrl_match_table[] = {
	{0x0, {MIIC_RTOS_PORT, MIIC_GMAC1_PORT, MIIC_SWITCH_PORTD,
	       MIIC_SWITCH_PORTC, MIIC_SERCOS_PORTB, MIIC_SERCOS_PORTA}},
	{0x1, {MIIC_RTOS_PORT, MIIC_GMAC1_PORT, MIIC_SWITCH_PORTD,
	       MIIC_SWITCH_PORTC, MIIC_ETHERCAT_PORTB, MIIC_ETHERCAT_PORTA}},
	{0x2, {MIIC_RTOS_PORT, MIIC_GMAC1_PORT, MIIC_SWITCH_PORTD,
	       MIIC_ETHERCAT_PORTC, MIIC_ETHERCAT_PORTB, MIIC_ETHERCAT_PORTA}},
	{0x3, {MIIC_RTOS_PORT, MIIC_GMAC1_PORT, MIIC_SWITCH_PORTD,
	       MIIC_SWITCH_PORTC, MIIC_SWITCH_PORTB, MIIC_SWITCH_PORTA}},

	{0x8, {MIIC_RTOS_PORT, MIIC_GMAC1_PORT, MIIC_SWITCH_PORTD,
	       MIIC_SWITCH_PORTC, MIIC_SERCOS_PORTB, MIIC_SERCOS_PORTA}},
	{0x9, {MIIC_RTOS_PORT, MIIC_GMAC1_PORT, MIIC_SWITCH_PORTD,
	       MIIC_SWITCH_PORTC, MIIC_ETHERCAT_PORTB, MIIC_ETHERCAT_PORTA}},
	{0xA, {MIIC_RTOS_PORT, MIIC_GMAC1_PORT, MIIC_SWITCH_PORTD,
	       MIIC_ETHERCAT_PORTC, MIIC_ETHERCAT_PORTB, MIIC_ETHERCAT_PORTA}},
	{0xB, {MIIC_RTOS_PORT, MIIC_GMAC1_PORT, MIIC_SWITCH_PORTD,
	       MIIC_SWITCH_PORTC, MIIC_SWITCH_PORTB, MIIC_SWITCH_PORTA}},

	{0x10, {MIIC_GMAC2_PORT, MIIC_GMAC1_PORT, MIIC_SWITCH_PORTD,
		MIIC_SWITCH_PORTC, MIIC_SERCOS_PORTB, MIIC_SERCOS_PORTA}},
	{0x11, {MIIC_GMAC2_PORT, MIIC_GMAC1_PORT, MIIC_SWITCH_PORTD,
		MIIC_SWITCH_PORTC, MIIC_ETHERCAT_PORTB, MIIC_ETHERCAT_PORTA}},
	{0x12, {MIIC_GMAC2_PORT, MIIC_GMAC1_PORT, MIIC_SWITCH_PORTD,
		MIIC_ETHERCAT_PORTC, MIIC_ETHERCAT_PORTB, MIIC_ETHERCAT_PORTA}},
	{0x13, {MIIC_GMAC2_PORT, MIIC_GMAC1_PORT, MIIC_SWITCH_PORTD,
		MIIC_SWITCH_PORTC, MIIC_SWITCH_PORTB, MIIC_SWITCH_PORTA}}
};

static const char * const conf_to_string[] = {
	[MIIC_GMAC1_PORT]	= "GMAC1_PORT",
	[MIIC_GMAC2_PORT]	= "GMAC2_PORT",
	[MIIC_RTOS_PORT]	= "RTOS_PORT",
	[MIIC_SERCOS_PORTA]	= "SERCOS_PORTA",
	[MIIC_SERCOS_PORTB]	= "SERCOS_PORTB",
	[MIIC_ETHERCAT_PORTA]	= "ETHERCAT_PORTA",
	[MIIC_ETHERCAT_PORTB]	= "ETHERCAT_PORTB",
	[MIIC_ETHERCAT_PORTC]	= "ETHERCAT_PORTC",
	[MIIC_SWITCH_PORTA]	= "SWITCH_PORTA",
	[MIIC_SWITCH_PORTB]	= "SWITCH_PORTB",
	[MIIC_SWITCH_PORTC]	= "SWITCH_PORTC",
	[MIIC_SWITCH_PORTD]	= "SWITCH_PORTD",
	[MIIC_HSR_PORTA]	= "HSR_PORTA",
	[MIIC_HSR_PORTB]	= "HSR_PORTB",
};

static const char *index_to_string[MIIC_MODCTRL_CONF_CONV_NUM] = {
	"SWITCH_PORTIN",
	"CONV1",
	"CONV2",
	"CONV3",
	"CONV4",
	"CONV5",
};

/**
 * struct miic - MII converter structure
 * @base: base address of the MII converter
 * @dev: Device associated to the MII converter
 * @lock: Lock used for read-modify-write access
 */
struct miic {
	void __iomem *base;
	struct device *dev;
	spinlock_t lock;
};

/**
 * struct miic_port - Per port MII converter struct
 * @miic: backiling to MII converter structure
 * @pcs: PCS structure associated to the port
 * @port: port number
 * @interface: interface mode of the port
 */
struct miic_port {
	struct miic *miic;
	struct phylink_pcs pcs;
	int port;
	phy_interface_t interface;
};

static struct miic_port *phylink_pcs_to_miic_port(struct phylink_pcs *pcs)
{
	return container_of(pcs, struct miic_port, pcs);
}

static void miic_reg_writel(struct miic *miic, int offset, u32 value)
{
	writel(value, miic->base + offset);
}

static u32 miic_reg_readl(struct miic *miic, int offset)
{
	return readl(miic->base + offset);
}

static void miic_reg_rmw(struct miic *miic, int offset, u32 mask, u32 val)
{
	u32 reg;

	spin_lock(&miic->lock);

	reg = miic_reg_readl(miic, offset);
	reg &= ~mask;
	reg |= val;
	miic_reg_writel(miic, offset, reg);

	spin_unlock(&miic->lock);
}

static void miic_converter_enable(struct miic *miic, int port, int enable)
{
	u32 val = 0;

	if (enable)
		val = MIIC_CONVRST_PHYIF_RST(port);

	miic_reg_rmw(miic, MIIC_CONVRST, MIIC_CONVRST_PHYIF_RST(port), val);
}

static int miic_config(struct phylink_pcs *pcs, unsigned int neg_mode,
		       phy_interface_t interface,
		       const unsigned long *advertising, bool permit)
{
	struct miic_port *miic_port = phylink_pcs_to_miic_port(pcs);
	struct miic *miic = miic_port->miic;
	u32 speed, conv_mode, val, mask;
	int port = miic_port->port;

	switch (interface) {
	case PHY_INTERFACE_MODE_RMII:
		conv_mode = CONV_MODE_RMII;
		speed = CONV_MODE_100MBPS;
		break;
	case PHY_INTERFACE_MODE_RGMII:
	case PHY_INTERFACE_MODE_RGMII_ID:
	case PHY_INTERFACE_MODE_RGMII_TXID:
	case PHY_INTERFACE_MODE_RGMII_RXID:
		conv_mode = CONV_MODE_RGMII;
		speed = CONV_MODE_1000MBPS;
		break;
	case PHY_INTERFACE_MODE_MII:
		conv_mode = CONV_MODE_MII;
		/* When in MII mode, speed should be set to 0 (which is actually
		 * CONV_MODE_10MBPS)
		 */
		speed = CONV_MODE_10MBPS;
		break;
	default:
		return -EOPNOTSUPP;
	}

	val = FIELD_PREP(MIIC_CONVCTRL_CONV_MODE, conv_mode);
	mask = MIIC_CONVCTRL_CONV_MODE;

	/* Update speed only if we are going to change the interface because
	 * the link might already be up and it would break it if the speed is
	 * changed.
	 */
	if (interface != miic_port->interface) {
		val |= FIELD_PREP(MIIC_CONVCTRL_CONV_SPEED, speed);
		mask |= MIIC_CONVCTRL_CONV_SPEED;
		miic_port->interface = interface;
	}

	miic_reg_rmw(miic, MIIC_CONVCTRL(port), mask, val);
	miic_converter_enable(miic, miic_port->port, 1);

	return 0;
}

static void miic_link_up(struct phylink_pcs *pcs, unsigned int neg_mode,
			 phy_interface_t interface, int speed, int duplex)
{
	struct miic_port *miic_port = phylink_pcs_to_miic_port(pcs);
	struct miic *miic = miic_port->miic;
	u32 conv_speed = 0, val = 0;
	int port = miic_port->port;

	if (duplex == DUPLEX_FULL)
		val |= MIIC_CONVCTRL_FULLD;

	/* No speed in MII through-mode */
	if (interface != PHY_INTERFACE_MODE_MII) {
		switch (speed) {
		case SPEED_1000:
			conv_speed = CONV_MODE_1000MBPS;
			break;
		case SPEED_100:
			conv_speed = CONV_MODE_100MBPS;
			break;
		case SPEED_10:
			conv_speed = CONV_MODE_10MBPS;
			break;
		default:
			return;
		}
	}

	val |= FIELD_PREP(MIIC_CONVCTRL_CONV_SPEED, conv_speed);

	miic_reg_rmw(miic, MIIC_CONVCTRL(port),
		     (MIIC_CONVCTRL_CONV_SPEED | MIIC_CONVCTRL_FULLD), val);
}

static int miic_validate(struct phylink_pcs *pcs, unsigned long *supported,
			 const struct phylink_link_state *state)
{
	if (phy_interface_mode_is_rgmii(state->interface) ||
	    state->interface == PHY_INTERFACE_MODE_RMII ||
	    state->interface == PHY_INTERFACE_MODE_MII)
		return 1;

	return -EINVAL;
}

static int miic_pre_init(struct phylink_pcs *pcs)
{
	struct miic_port *miic_port = phylink_pcs_to_miic_port(pcs);
	struct miic *miic = miic_port->miic;
	u32 val, mask;

	/* Start RX clock if required */
	if (pcs->rxc_always_on) {
		/* In MII through mode, the clock signals will be driven by the
		 * external PHY, which might not be initialized yet. Set RMII
		 * as default mode to ensure that a reference clock signal is
		 * generated.
		 */
		miic_port->interface = PHY_INTERFACE_MODE_RMII;

		val = FIELD_PREP(MIIC_CONVCTRL_CONV_MODE, CONV_MODE_RMII) |
		      FIELD_PREP(MIIC_CONVCTRL_CONV_SPEED, CONV_MODE_100MBPS);
		mask = MIIC_CONVCTRL_CONV_MODE | MIIC_CONVCTRL_CONV_SPEED;

		miic_reg_rmw(miic, MIIC_CONVCTRL(miic_port->port), mask, val);

		miic_converter_enable(miic, miic_port->port, 1);
	}

	return 0;
}

static const struct phylink_pcs_ops miic_phylink_ops = {
	.pcs_validate = miic_validate,
	.pcs_config = miic_config,
	.pcs_link_up = miic_link_up,
	.pcs_pre_init = miic_pre_init,
};

struct phylink_pcs *miic_create(struct device *dev, struct device_node *np)
{
	struct platform_device *pdev;
	struct miic_port *miic_port;
	struct device_node *pcs_np;
	struct miic *miic;
	u32 port;

	if (!of_device_is_available(np))
		return ERR_PTR(-ENODEV);

	if (of_property_read_u32(np, "reg", &port))
		return ERR_PTR(-EINVAL);

	if (port > MIIC_MAX_NR_PORTS || port < 1)
		return ERR_PTR(-EINVAL);

	/* The PCS pdev is attached to the parent node */
	pcs_np = of_get_parent(np);
	if (!pcs_np)
		return ERR_PTR(-ENODEV);

	if (!of_device_is_available(pcs_np)) {
		of_node_put(pcs_np);
		return ERR_PTR(-ENODEV);
	}

	pdev = of_find_device_by_node(pcs_np);
	of_node_put(pcs_np);
	if (!pdev || !platform_get_drvdata(pdev)) {
		if (pdev)
			put_device(&pdev->dev);
		return ERR_PTR(-EPROBE_DEFER);
	}

	miic_port = kzalloc(sizeof(*miic_port), GFP_KERNEL);
	if (!miic_port) {
		put_device(&pdev->dev);
		return ERR_PTR(-ENOMEM);
	}

	miic = platform_get_drvdata(pdev);
	device_link_add(dev, miic->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
	put_device(&pdev->dev);

	miic_port->miic = miic;
	miic_port->port = port - 1;
	miic_port->pcs.ops = &miic_phylink_ops;
	miic_port->pcs.neg_mode = true;

	return &miic_port->pcs;
}
EXPORT_SYMBOL(miic_create);

void miic_destroy(struct phylink_pcs *pcs)
{
	struct miic_port *miic_port = phylink_pcs_to_miic_port(pcs);

	miic_converter_enable(miic_port->miic, miic_port->port, 0);
	kfree(miic_port);
}
EXPORT_SYMBOL(miic_destroy);

static int miic_init_hw(struct miic *miic, u32 cfg_mode)
{
	int port;

	/* Unlock write access to accessory registers (cf datasheet). If this
	 * is going to be used in conjunction with the Cortex-M3, this sequence
	 * will have to be moved in register write
	 */
	miic_reg_writel(miic, MIIC_PRCMD, 0x00A5);
	miic_reg_writel(miic, MIIC_PRCMD, 0x0001);
	miic_reg_writel(miic, MIIC_PRCMD, 0xFFFE);
	miic_reg_writel(miic, MIIC_PRCMD, 0x0001);

	miic_reg_writel(miic, MIIC_MODCTRL,
			FIELD_PREP(MIIC_MODCTRL_SW_MODE, cfg_mode));

	for (port = 0; port < MIIC_MAX_NR_PORTS; port++) {
		miic_converter_enable(miic, port, 0);
		/* Disable speed/duplex control from these registers, datasheet
		 * says switch registers should be used to setup switch port
		 * speed and duplex.
		 */
		miic_reg_writel(miic, MIIC_SWCTRL, 0x0);
		miic_reg_writel(miic, MIIC_SWDUPC, 0x0);
	}

	return 0;
}

static bool miic_modctrl_match(s8 table_val[MIIC_MODCTRL_CONF_CONV_NUM],
			       s8 dt_val[MIIC_MODCTRL_CONF_CONV_NUM])
{
	int i;

	for (i = 0; i < MIIC_MODCTRL_CONF_CONV_NUM; i++) {
		if (dt_val[i] == MIIC_MODCTRL_CONF_NONE)
			continue;

		if (dt_val[i] != table_val[i])
			return false;
	}

	return true;
}

static void miic_dump_conf(struct device *dev,
			   s8 conf[MIIC_MODCTRL_CONF_CONV_NUM])
{
	const char *conf_name;
	int i;

	for (i = 0; i < MIIC_MODCTRL_CONF_CONV_NUM; i++) {
		if (conf[i] != MIIC_MODCTRL_CONF_NONE)
			conf_name = conf_to_string[conf[i]];
		else
			conf_name = "NONE";

		dev_err(dev, "%s: %s\n", index_to_string[i], conf_name);
	}
}

static int miic_match_dt_conf(struct device *dev,
			      s8 dt_val[MIIC_MODCTRL_CONF_CONV_NUM],
			      u32 *mode_cfg)
{
	struct modctrl_match *table_entry;
	int i;

	for (i = 0; i < ARRAY_SIZE(modctrl_match_table); i++) {
		table_entry = &modctrl_match_table[i];

		if (miic_modctrl_match(table_entry->conv, dt_val)) {
			*mode_cfg = table_entry->mode_cfg;
			return 0;
		}
	}

	dev_err(dev, "Failed to apply requested configuration\n");
	miic_dump_conf(dev, dt_val);

	return -EINVAL;
}

static int miic_parse_dt(struct device *dev, u32 *mode_cfg)
{
	s8 dt_val[MIIC_MODCTRL_CONF_CONV_NUM];
	struct device_node *np = dev->of_node;
	struct device_node *conv;
	u32 conf;
	int port;

	memset(dt_val, MIIC_MODCTRL_CONF_NONE, sizeof(dt_val));

	if (of_property_read_u32(np, "renesas,miic-switch-portin", &conf) == 0)
		dt_val[0] = conf;

	for_each_child_of_node(np, conv) {
		if (of_property_read_u32(conv, "reg", &port))
			continue;

		if (!of_device_is_available(conv))
			continue;

		if (of_property_read_u32(conv, "renesas,miic-input", &conf) == 0)
			dt_val[port] = conf;
	}

	return miic_match_dt_conf(dev, dt_val, mode_cfg);
}

static int miic_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct miic *miic;
	u32 mode_cfg;
	int ret;

	ret = miic_parse_dt(dev, &mode_cfg);
	if (ret < 0)
		return ret;

	miic = devm_kzalloc(dev, sizeof(*miic), GFP_KERNEL);
	if (!miic)
		return -ENOMEM;

	spin_lock_init(&miic->lock);
	miic->dev = dev;
	miic->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(miic->base))
		return PTR_ERR(miic->base);

	ret = devm_pm_runtime_enable(dev);
	if (ret < 0)
		return ret;

	ret = pm_runtime_resume_and_get(dev);
	if (ret < 0)
		return ret;

	ret = miic_init_hw(miic, mode_cfg);
	if (ret)
		goto disable_runtime_pm;

	/* miic_create() relies on that fact that data are attached to the
	 * platform device to determine if the driver is ready so this needs to
	 * be the last thing to be done after everything is initialized
	 * properly.
	 */
	platform_set_drvdata(pdev, miic);

	return 0;

disable_runtime_pm:
	pm_runtime_put(dev);

	return ret;
}

static void miic_remove(struct platform_device *pdev)
{
	pm_runtime_put(&pdev->dev);
}

static const struct of_device_id miic_of_mtable[] = {
	{ .compatible = "renesas,rzn1-miic" },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, miic_of_mtable);

static struct platform_driver miic_driver = {
	.driver = {
		.name	 = "rzn1_miic",
		.suppress_bind_attrs = true,
		.of_match_table = miic_of_mtable,
	},
	.probe = miic_probe,
	.remove_new = miic_remove,
};
module_platform_driver(miic_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Renesas MII converter PCS driver");
MODULE_AUTHOR("Clément Léger <clement.leger@bootlin.com>");