// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2016, NVIDIA CORPORATION.
 * Copyright (c) 2019, Ahmad Fatoum, Pengutronix
 *
 * Portions based on U-Boot's rtl8169.c and dwc_eth_qos.
 */

#include <common.h>
#include <init.h>
#include <gpio.h>
#include <of_gpio.h>
#include <linux/clk.h>
#include <net.h>
#include <linux/reset.h>

#include "designware_eqos.h"

/* These registers are Tegra186-specific */
#define EQOS_TEGRA186_REGS_BASE 0x8800
struct eqos_tegra186_regs {
	uint32_t sdmemcomppadctrl;			/* 0x8800 */
	uint32_t auto_cal_config;			/* 0x8804 */
	uint32_t unused_8808;				/* 0x8808 */
	uint32_t auto_cal_status;			/* 0x880c */
};

#define EQOS_SDMEMCOMPPADCTRL_PAD_E_INPUT_OR_E_PWRD	BIT(31)

#define EQOS_AUTO_CAL_CONFIG_START			BIT(31)
#define EQOS_AUTO_CAL_CONFIG_ENABLE			BIT(29)

#define EQOS_AUTO_CAL_STATUS_ACTIVE			BIT(31)

struct eqos_tegra186 {
	struct clk_bulk_data *clks;
	int num_clks;
	struct reset_control	*rst;
	struct eqos_tegra186_regs __iomem *tegra186_regs;
	int phy_reset_gpio;
};

static inline struct eqos_tegra186 *to_tegra186(struct eqos *eqos)
{
	return eqos->priv;
}

enum { CLK_SLAVE_BUS, CLK_MASTER_BUS, CLK_RX, CLK_PTP_REF, CLK_TX };
static const struct clk_bulk_data tegra186_clks[] = {
	[CLK_SLAVE_BUS]  = { .id = "slave_bus" },
	[CLK_MASTER_BUS] = { .id = "master_bus" },
	[CLK_RX]         = { .id = "rx" },
	[CLK_PTP_REF]    = { .id = "ptp_ref" },
	[CLK_TX]         = { .id = "tx" },
};

static int eqos_clks_set_rate_tegra186(struct eqos_tegra186 *priv)
{
	return clk_set_rate(priv->clks[CLK_PTP_REF].clk, 125 * 1000 * 1000);
}

static int eqos_reset_tegra186(struct eqos_tegra186 *priv, bool reset)
{
	int ret;

	if (reset) {
		reset_control_assert(priv->rst);
		gpio_set_value(priv->phy_reset_gpio, 1);
		return 0;
	}

	gpio_set_value(priv->phy_reset_gpio, 1);

	udelay(2);

	gpio_set_value(priv->phy_reset_gpio, 0);

	ret = reset_control_assert(priv->rst);
	if (ret < 0)
		return ret;

	udelay(2);

	return reset_control_deassert(priv->rst);
}

static int eqos_calibrate_pads_tegra186(struct eqos *eqos)
{
	struct eqos_tegra186 *priv = to_tegra186(eqos);
	u32 active;
	int ret;

	setbits_le32(&priv->tegra186_regs->sdmemcomppadctrl,
		     EQOS_SDMEMCOMPPADCTRL_PAD_E_INPUT_OR_E_PWRD);

	udelay(1);

	setbits_le32(&priv->tegra186_regs->auto_cal_config,
		     EQOS_AUTO_CAL_CONFIG_START | EQOS_AUTO_CAL_CONFIG_ENABLE);

	ret = readl_poll_timeout(&priv->tegra186_regs->auto_cal_status, active,
				 active & EQOS_AUTO_CAL_STATUS_ACTIVE,
				 10000);
	if (ret) {
		eqos_err(eqos, "calibrate didn't start\n");
		goto failed;
	}

	ret = readl_poll_timeout(&priv->tegra186_regs->auto_cal_status, active,
				 !(active & EQOS_AUTO_CAL_STATUS_ACTIVE),
				 10000);
	if (ret) {
		eqos_err(eqos, "calibrate didn't finish\n");
		goto failed;
	}

failed:
	clrbits_le32(&priv->tegra186_regs->sdmemcomppadctrl,
		     EQOS_SDMEMCOMPPADCTRL_PAD_E_INPUT_OR_E_PWRD);

	return ret;
}

static int eqos_calibrate_link_tegra186(struct eqos *eqos, unsigned speed)
{
	struct eqos_tegra186 *priv = to_tegra186(eqos);
	int ret = 0;
	unsigned long rate;
	bool calibrate;

	switch (speed) {
	case SPEED_1000:
		rate = 125 * 1000 * 1000;
		calibrate = true;
		break;
	case SPEED_100:
		rate = 25 * 1000 * 1000;
		calibrate = true;
		break;
	case SPEED_10:
		rate = 2.5 * 1000 * 1000;
		calibrate = false;
		break;
	default:
		return -EINVAL;
	}

	if (calibrate) {
		ret = eqos_calibrate_pads_tegra186(eqos);
		if (ret)
			return ret;
	} else {
		clrbits_le32(&priv->tegra186_regs->auto_cal_config,
			     EQOS_AUTO_CAL_CONFIG_ENABLE);
	}

	ret = clk_set_rate(priv->clks[CLK_TX].clk, rate);
	if (ret < 0) {
		eqos_err(eqos, "clk_set_rate(tx_clk, %lu) failed: %d\n", rate, ret);
		return ret;
	}

	return 0;
}

static unsigned long eqos_get_csr_clk_rate_tegra186(struct eqos *eqos)
{
	return clk_get_rate(to_tegra186(eqos)->clks[CLK_SLAVE_BUS].clk);
}

static int eqos_set_ethaddr_tegra186(struct eth_device *edev, const unsigned char *mac)
{
	struct eqos *eqos = edev->priv;

	/*
	 * This function may be called before start() or after stop(). At that
	 * time, on at least some configurations of the EQoS HW, all clocks to
	 * the EQoS HW block will be stopped, and a reset signal applied. If
	 * any register access is attempted in this state, bus timeouts or CPU
	 * hangs may occur. This check prevents that.
	 *
	 * A simple solution to this problem would be to not implement
	 * write_hwaddr(), since start() always writes the MAC address into HW
	 * anyway. However, it is desirable to implement write_hwaddr() to
	 * support the case of SW that runs subsequent to U-Boot which expects
	 * the MAC address to already be programmed into the EQoS registers,
	 * which must happen irrespective of whether the U-Boot user (or
	 * scripts) actually made use of the EQoS device, and hence
	 * irrespective of whether start() was ever called.
	 *
	 * Note that this requirement by subsequent SW is not valid for
	 * Tegra186, and is likely not valid for any non-PCI instantiation of
	 * the EQoS HW block. This function is implemented solely as
	 * future-proofing with the expectation the driver will eventually be
	 * ported to some system where the expectation above is true.
	 */

	if (!edev->active) {
		memcpy(eqos->macaddr, mac, 6);
		return 0;
	}

	return eqos_set_ethaddr(edev, mac);
}

static int eqos_init_tegra186(struct device *dev, struct eqos *eqos)
{
	struct eqos_tegra186 *priv = to_tegra186(eqos);
	int phy_reset;
	int ret;

	priv->tegra186_regs = IOMEM(eqos->regs + EQOS_TEGRA186_REGS_BASE);

	priv->rst = reset_control_get(dev, "eqos");
	if (IS_ERR(priv->rst)) {
		dev_err(dev, "reset_get_by_name(rst) failed: %pe\n", priv->rst);
		return PTR_ERR(priv->rst);
	}

	phy_reset = of_get_named_gpio(dev->of_node, "phy-reset-gpios", 0);
	if (gpio_is_valid(phy_reset)) {
		ret = gpio_request(phy_reset, "phy-reset");
		if (ret)
			goto release_res;

		priv->phy_reset_gpio = phy_reset;
	}

	priv->clks = xmemdup(tegra186_clks, sizeof(tegra186_clks));
	priv->num_clks = ARRAY_SIZE(tegra186_clks);

	ret = clk_bulk_enable(priv->num_clks, priv->clks);
	if (ret < 0) {
		eqos_err(eqos, "clk_bulk_enable() failed: %s\n", strerror(-ret));
		goto release_res;
	}

	ret = eqos_clks_set_rate_tegra186(priv);
	if (ret < 0) {
		eqos_err(eqos, "clks_set_rate() failed: %s\n", strerror(-ret));
		goto err_stop_clks;
	}

	eqos_reset_tegra186(priv, false);
	if (ret < 0) {
		eqos_err(eqos, "reset(0) failed: %s\n", strerror(-ret));
		goto err_stop_clks;
	}

	return 0;

err_stop_clks:
	clk_bulk_disable(priv->num_clks, priv->clks);
release_res:
	reset_control_put(priv->rst);

	return ret;
}

static void eqos_adjust_link_tegra186(struct eth_device *edev)
{
	struct eqos *eqos = edev->priv;
	unsigned speed = edev->phydev->speed;
	int ret;

	eqos_adjust_link(edev);

	ret = eqos_calibrate_link_tegra186(eqos, speed);
	if (ret < 0) {
		eqos_err(eqos, "eqos_calibrate_link_tegra186() failed: %d\n", ret);
		return;
	}
}

static const struct eqos_ops tegra186_ops = {
	.init = eqos_init_tegra186,
	.get_ethaddr = eqos_get_ethaddr,
	.set_ethaddr = eqos_set_ethaddr_tegra186,
	.adjust_link = eqos_adjust_link_tegra186,
	.get_csr_clk_rate = eqos_get_csr_clk_rate_tegra186,

	.clk_csr = EQOS_MDIO_ADDR_CR_20_35,
	.config_mac = EQOS_MAC_RXQ_CTRL0_RXQ0EN_ENABLED_DCB,
};

static int eqos_probe_tegra186(struct device *dev)
{
	return eqos_probe(dev, &tegra186_ops, xzalloc(sizeof(struct eqos_tegra186)));
}

static void eqos_remove_tegra186(struct device *dev)
{
	struct eqos_tegra186 *priv = to_tegra186(dev->priv);

	eqos_remove(dev);

	eqos_reset_tegra186(priv, true);

	clk_bulk_disable(priv->num_clks, priv->clks);

	clk_bulk_put(priv->num_clks, priv->clks);

	gpio_free(priv->phy_reset_gpio);
	reset_control_put(priv->rst);
}

static const struct of_device_id eqos_tegra186_ids[] = {
	{ .compatible = "nvidia,tegra186-eqos" },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, eqos_tegra186_ids);

static struct driver eqos_tegra186_driver = {
	.name = "eqos-tegra186",
	.probe = eqos_probe_tegra186,
	.remove	= eqos_remove_tegra186,
	.of_compatible = DRV_OF_COMPAT(eqos_tegra186_ids),
};
device_platform_driver(eqos_tegra186_driver);