// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2018 Russell King, Deep Blue Solutions Ltd.
 *
 * Partly derived from CP110 comphy driver by Antoine Tenart
 * <antoine.tenart@bootlin.com>
 */
#include <linux/delay.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/phy/phy.h>
#include <linux/phy.h>
#include <linux/platform_device.h>

#define MAX_A38X_COMPHY	6
#define MAX_A38X_PORTS	3

#define COMPHY_CFG1		0x00
#define  COMPHY_CFG1_GEN_TX(x)		((x) << 26)
#define  COMPHY_CFG1_GEN_TX_MSK		COMPHY_CFG1_GEN_TX(15)
#define  COMPHY_CFG1_GEN_RX(x)		((x) << 22)
#define  COMPHY_CFG1_GEN_RX_MSK		COMPHY_CFG1_GEN_RX(15)
#define  GEN_SGMII_1_25GBPS		6
#define  GEN_SGMII_3_125GBPS		8

#define COMPHY_STAT1		0x18
#define  COMPHY_STAT1_PLL_RDY_TX	BIT(3)
#define  COMPHY_STAT1_PLL_RDY_RX	BIT(2)

#define COMPHY_SELECTOR		0xfc

struct a38x_comphy;

struct a38x_comphy_lane {
	void __iomem *base;
	struct a38x_comphy *priv;
	unsigned int n;

	int port;
};

struct a38x_comphy {
	void __iomem *base;
	void __iomem *conf;
	struct device *dev;
	struct a38x_comphy_lane lane[MAX_A38X_COMPHY];
};

/*
 * Map serdes lanes and gbe ports to serdes mux configuration values:
 * row index = serdes lane,
 * column index = gbe port number.
 */
static const u8 gbe_mux[MAX_A38X_COMPHY][MAX_A38X_PORTS] = {
	{ 3, 0, 0 },
	{ 4, 5, 0 },
	{ 0, 4, 0 },
	{ 0, 0, 4 },
	{ 0, 3, 0 },
	{ 0, 0, 3 },
};

static void a38x_set_conf(struct a38x_comphy_lane *lane, bool enable)
{
	struct a38x_comphy *priv = lane->priv;
	u32 conf;

	if (priv->conf) {
		conf = readl_relaxed(priv->conf);
		if (enable)
			conf |= BIT(lane->port);
		else
			conf &= ~BIT(lane->port);
		writel(conf, priv->conf);
	}
}

static void a38x_comphy_set_reg(struct a38x_comphy_lane *lane,
				unsigned int offset, u32 mask, u32 value)
{
	u32 val;

	val = readl_relaxed(lane->base + offset) & ~mask;
	writel(val | value, lane->base + offset);
}

static void a38x_comphy_set_speed(struct a38x_comphy_lane *lane,
				  unsigned int gen_tx, unsigned int gen_rx)
{
	a38x_comphy_set_reg(lane, COMPHY_CFG1,
			    COMPHY_CFG1_GEN_TX_MSK | COMPHY_CFG1_GEN_RX_MSK,
			    COMPHY_CFG1_GEN_TX(gen_tx) |
		            COMPHY_CFG1_GEN_RX(gen_rx));
}

static int a38x_comphy_poll(struct a38x_comphy_lane *lane,
			    unsigned int offset, u32 mask, u32 value)
{
	u32 val;
	int ret;

	ret = readl_relaxed_poll_timeout_atomic(lane->base + offset, val,
						(val & mask) == value,
						1000, 150000);

	if (ret)
		dev_err(lane->priv->dev,
			"comphy%u: timed out waiting for status\n", lane->n);

	return ret;
}

/*
 * We only support changing the speed for comphys configured for GBE.
 * Since that is all we do, we only poll for PLL ready status.
 */
static int a38x_comphy_set_mode(struct phy *phy, enum phy_mode mode, int sub)
{
	struct a38x_comphy_lane *lane = phy_get_drvdata(phy);
	unsigned int gen;
	int ret;

	if (mode != PHY_MODE_ETHERNET)
		return -EINVAL;

	switch (sub) {
	case PHY_INTERFACE_MODE_SGMII:
	case PHY_INTERFACE_MODE_1000BASEX:
		gen = GEN_SGMII_1_25GBPS;
		break;

	case PHY_INTERFACE_MODE_2500BASEX:
		gen = GEN_SGMII_3_125GBPS;
		break;

	default:
		return -EINVAL;
	}

	a38x_set_conf(lane, false);

	a38x_comphy_set_speed(lane, gen, gen);

	ret = a38x_comphy_poll(lane, COMPHY_STAT1,
			       COMPHY_STAT1_PLL_RDY_TX |
			       COMPHY_STAT1_PLL_RDY_RX,
			       COMPHY_STAT1_PLL_RDY_TX |
			       COMPHY_STAT1_PLL_RDY_RX);

	if (ret == 0)
		a38x_set_conf(lane, true);

	return ret;
}

static const struct phy_ops a38x_comphy_ops = {
	.set_mode	= a38x_comphy_set_mode,
	.owner		= THIS_MODULE,
};

static struct phy *a38x_comphy_xlate(struct device *dev,
				     const struct of_phandle_args *args)
{
	struct a38x_comphy_lane *lane;
	struct phy *phy;
	u32 val;

	if (WARN_ON(args->args[0] >= MAX_A38X_PORTS))
		return ERR_PTR(-EINVAL);

	phy = of_phy_simple_xlate(dev, args);
	if (IS_ERR(phy))
		return phy;

	lane = phy_get_drvdata(phy);
	if (lane->port >= 0)
		return ERR_PTR(-EBUSY);

	lane->port = args->args[0];

	val = readl_relaxed(lane->priv->base + COMPHY_SELECTOR);
	val = (val >> (4 * lane->n)) & 0xf;

	if (!gbe_mux[lane->n][lane->port] ||
	    val != gbe_mux[lane->n][lane->port]) {
		dev_warn(lane->priv->dev,
			 "comphy%u: not configured for GBE\n", lane->n);
		phy = ERR_PTR(-EINVAL);
	}

	return phy;
}

static int a38x_comphy_probe(struct platform_device *pdev)
{
	struct phy_provider *provider;
	struct device_node *child;
	struct a38x_comphy *priv;
	struct resource *res;
	void __iomem *base;

	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(base))
		return PTR_ERR(base);

	priv->dev = &pdev->dev;
	priv->base = base;

	/* Optional */
	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "conf");
	if (res) {
		priv->conf = devm_ioremap_resource(&pdev->dev, res);
		if (IS_ERR(priv->conf))
			return PTR_ERR(priv->conf);
	}

	for_each_available_child_of_node(pdev->dev.of_node, child) {
		struct phy *phy;
		int ret;
		u32 val;

		ret = of_property_read_u32(child, "reg", &val);
		if (ret < 0) {
			dev_err(&pdev->dev, "missing 'reg' property (%d)\n",
				ret);
			continue;
		}

		if (val >= MAX_A38X_COMPHY || priv->lane[val].base) {
			dev_err(&pdev->dev, "invalid 'reg' property\n");
			continue;
		}

		phy = devm_phy_create(&pdev->dev, child, &a38x_comphy_ops);
		if (IS_ERR(phy)) {
			of_node_put(child);
			return PTR_ERR(phy);
		}

		priv->lane[val].base = base + 0x28 * val;
		priv->lane[val].priv = priv;
		priv->lane[val].n = val;
		priv->lane[val].port = -1;
		phy_set_drvdata(phy, &priv->lane[val]);
	}

	dev_set_drvdata(&pdev->dev, priv);

	provider = devm_of_phy_provider_register(&pdev->dev, a38x_comphy_xlate);

	return PTR_ERR_OR_ZERO(provider);
}

static const struct of_device_id a38x_comphy_of_match_table[] = {
	{ .compatible = "marvell,armada-380-comphy" },
	{ },
};
MODULE_DEVICE_TABLE(of, a38x_comphy_of_match_table);

static struct platform_driver a38x_comphy_driver = {
	.probe	= a38x_comphy_probe,
	.driver	= {
		.name = "armada-38x-comphy",
		.of_match_table = a38x_comphy_of_match_table,
	},
};
module_platform_driver(a38x_comphy_driver);

MODULE_AUTHOR("Russell King <rmk+kernel@armlinux.org.uk>");
MODULE_DESCRIPTION("Common PHY driver for Armada 38x SoCs");
MODULE_LICENSE("GPL v2");