// SPDX-License-Identifier: GPL-2.0-only
/*
 * Rockchip PCIe PHY driver
 *
 * Copyright (C) 2016 Shawn Lin <shawn.lin@rock-chips.com>
 * Copyright (C) 2016 ROCKCHIP, Inc.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/hw_bitfield.h>
#include <linux/io.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/reset.h>


#define PHY_MAX_LANE_NUM      4
#define PHY_CFG_DATA_MASK     GENMASK(10, 7)
#define PHY_CFG_ADDR_MASK     GENMASK(6, 1)
#define PHY_CFG_WR_ENABLE     1
#define PHY_CFG_WR_DISABLE    0
#define PHY_CFG_WR_MASK       BIT(0)
#define PHY_CFG_PLL_LOCK      0x10
#define PHY_CFG_CLK_TEST      0x10
#define PHY_CFG_CLK_SCC       0x12
#define PHY_CFG_SEPE_RATE     BIT(3)
#define PHY_CFG_PLL_100M      BIT(3)
#define PHY_PLL_LOCKED        BIT(9)
#define PHY_PLL_OUTPUT        BIT(10)
#define PHY_LANE_A_STATUS     0x30
#define PHY_LANE_B_STATUS     0x31
#define PHY_LANE_C_STATUS     0x32
#define PHY_LANE_D_STATUS     0x33
#define PHY_LANE_RX_DET_SHIFT 11
#define PHY_LANE_RX_DET_TH    0x1
#define PHY_LANE_IDLE_OFF     0x1
#define PHY_LANE_IDLE_MASK    BIT(3)

struct rockchip_pcie_data {
	unsigned int pcie_conf;
	unsigned int pcie_status;
	unsigned int pcie_laneoff;
};

struct rockchip_pcie_phy {
	const struct rockchip_pcie_data *phy_data;
	struct regmap *reg_base;
	struct phy_pcie_instance {
		struct phy *phy;
		u32 index;
	} phys[PHY_MAX_LANE_NUM];
	struct mutex pcie_mutex;
	struct reset_control *phy_rst;
	struct clk *clk_pciephy_ref;
	int pwr_cnt;
	int init_cnt;
};

static struct rockchip_pcie_phy *to_pcie_phy(struct phy_pcie_instance *inst)
{
	return container_of(inst, struct rockchip_pcie_phy,
					phys[inst->index]);
}

static struct phy *rockchip_pcie_phy_of_xlate(struct device *dev,
					      const struct of_phandle_args *args)
{
	struct rockchip_pcie_phy *rk_phy = dev_get_drvdata(dev);

	if (args->args_count == 0)
		return rk_phy->phys[0].phy;

	if (WARN_ON(args->args[0] >= PHY_MAX_LANE_NUM))
		return ERR_PTR(-ENODEV);

	return rk_phy->phys[args->args[0]].phy;
}


static inline void phy_wr_cfg(struct rockchip_pcie_phy *rk_phy,
			      u32 addr, u32 data)
{
	regmap_write(rk_phy->reg_base, rk_phy->phy_data->pcie_conf,
		     FIELD_PREP_WM16(PHY_CFG_DATA_MASK, data) |
		     FIELD_PREP_WM16(PHY_CFG_ADDR_MASK, addr));
	udelay(1);
	regmap_write(rk_phy->reg_base, rk_phy->phy_data->pcie_conf,
		     FIELD_PREP_WM16(PHY_CFG_WR_MASK, PHY_CFG_WR_ENABLE));
	udelay(1);
	regmap_write(rk_phy->reg_base, rk_phy->phy_data->pcie_conf,
		     FIELD_PREP_WM16(PHY_CFG_WR_MASK, PHY_CFG_WR_DISABLE));
}

static int rockchip_pcie_phy_power_off(struct phy *phy)
{
	struct phy_pcie_instance *inst = phy_get_drvdata(phy);
	struct rockchip_pcie_phy *rk_phy = to_pcie_phy(inst);
	int err = 0;

	guard(mutex)(&rk_phy->pcie_mutex);

	regmap_write(rk_phy->reg_base, rk_phy->phy_data->pcie_laneoff,
		     FIELD_PREP_WM16(PHY_LANE_IDLE_MASK,
				     PHY_LANE_IDLE_OFF) << inst->index);

	if (--rk_phy->pwr_cnt) {
		return 0;
	}

	err = reset_control_assert(rk_phy->phy_rst);
	if (err) {
		dev_err(&phy->dev, "assert phy_rst err %d\n", err);
		rk_phy->pwr_cnt++;
		regmap_write(rk_phy->reg_base, rk_phy->phy_data->pcie_laneoff,
			     FIELD_PREP_WM16(PHY_LANE_IDLE_MASK,
					     !PHY_LANE_IDLE_OFF) << inst->index);
		return err;
	}

	return err;
}

static int rockchip_pcie_phy_power_on(struct phy *phy)
{
	struct phy_pcie_instance *inst = phy_get_drvdata(phy);
	struct rockchip_pcie_phy *rk_phy = to_pcie_phy(inst);
	int err = 0;
	u32 status;

	guard(mutex)(&rk_phy->pcie_mutex);

	regmap_write(rk_phy->reg_base, rk_phy->phy_data->pcie_laneoff,
		     FIELD_PREP_WM16(PHY_LANE_IDLE_MASK,
				     !PHY_LANE_IDLE_OFF) << inst->index);

	if (rk_phy->pwr_cnt++) {
		return 0;
	}

	err = reset_control_deassert(rk_phy->phy_rst);
	if (err) {
		dev_err(&phy->dev, "deassert phy_rst err %d\n", err);
		rk_phy->pwr_cnt--;
		return err;
	}

	regmap_write(rk_phy->reg_base, rk_phy->phy_data->pcie_conf,
		     FIELD_PREP_WM16(PHY_CFG_ADDR_MASK, PHY_CFG_PLL_LOCK));

	/*
	 * No documented timeout value for phy operation below,
	 * so we make it large enough here. And we use loop-break
	 * method which should not be harmful.
	 */
	err = regmap_read_poll_timeout(rk_phy->reg_base,
				       rk_phy->phy_data->pcie_status,
				       status,
				       status & PHY_PLL_LOCKED,
				       200, 100000);
	if (err) {
		dev_err(&phy->dev, "pll lock timeout!\n");
		goto err_pll_lock;
	}

	phy_wr_cfg(rk_phy, PHY_CFG_CLK_TEST, PHY_CFG_SEPE_RATE);
	phy_wr_cfg(rk_phy, PHY_CFG_CLK_SCC, PHY_CFG_PLL_100M);

	err = regmap_read_poll_timeout(rk_phy->reg_base,
				       rk_phy->phy_data->pcie_status,
				       status,
				       !(status & PHY_PLL_OUTPUT),
				       200, 100000);
	if (err) {
		dev_err(&phy->dev, "pll output enable timeout!\n");
		goto err_pll_lock;
	}

	regmap_write(rk_phy->reg_base, rk_phy->phy_data->pcie_conf,
		     FIELD_PREP_WM16(PHY_CFG_ADDR_MASK, PHY_CFG_PLL_LOCK));

	err = regmap_read_poll_timeout(rk_phy->reg_base,
				       rk_phy->phy_data->pcie_status,
				       status,
				       status & PHY_PLL_LOCKED,
				       200, 100000);
	if (err) {
		dev_err(&phy->dev, "pll relock timeout!\n");
		goto err_pll_lock;
	}

	return err;

err_pll_lock:
	reset_control_assert(rk_phy->phy_rst);
	rk_phy->pwr_cnt--;
	return err;
}

static int rockchip_pcie_phy_init(struct phy *phy)
{
	struct phy_pcie_instance *inst = phy_get_drvdata(phy);
	struct rockchip_pcie_phy *rk_phy = to_pcie_phy(inst);
	int err = 0;

	guard(mutex)(&rk_phy->pcie_mutex);

	if (rk_phy->init_cnt++) {
		return 0;
	}

	err = reset_control_assert(rk_phy->phy_rst);
	if (err) {
		dev_err(&phy->dev, "assert phy_rst err %d\n", err);
		rk_phy->init_cnt--;
		return err;
	}

	return err;
}

static int rockchip_pcie_phy_exit(struct phy *phy)
{
	struct phy_pcie_instance *inst = phy_get_drvdata(phy);
	struct rockchip_pcie_phy *rk_phy = to_pcie_phy(inst);

	guard(mutex)(&rk_phy->pcie_mutex);

	if (--rk_phy->init_cnt)
		goto err_init_cnt;

err_init_cnt:
	return 0;
}

static const struct phy_ops ops = {
	.init		= rockchip_pcie_phy_init,
	.exit		= rockchip_pcie_phy_exit,
	.power_on	= rockchip_pcie_phy_power_on,
	.power_off	= rockchip_pcie_phy_power_off,
	.owner		= THIS_MODULE,
};

static const struct rockchip_pcie_data rk3399_pcie_data = {
	.pcie_conf = 0xe220,
	.pcie_status = 0xe2a4,
	.pcie_laneoff = 0xe214,
};

static const struct of_device_id rockchip_pcie_phy_dt_ids[] = {
	{
		.compatible = "rockchip,rk3399-pcie-phy",
		.data = &rk3399_pcie_data,
	},
	{}
};

MODULE_DEVICE_TABLE(of, rockchip_pcie_phy_dt_ids);

static int rockchip_pcie_phy_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct rockchip_pcie_phy *rk_phy;
	struct phy_provider *phy_provider;
	struct regmap *grf;
	int i;
	u32 phy_num;

	grf = syscon_node_to_regmap(dev->parent->of_node);
	if (IS_ERR(grf)) {
		dev_err(dev, "Cannot find GRF syscon\n");
		return PTR_ERR(grf);
	}

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

	rk_phy->phy_data = device_get_match_data(&pdev->dev);
	if (!rk_phy->phy_data)
		return -EINVAL;

	rk_phy->reg_base = grf;

	mutex_init(&rk_phy->pcie_mutex);

	rk_phy->phy_rst = devm_reset_control_get(dev, "phy");
	if (IS_ERR(rk_phy->phy_rst))
		return dev_err_probe(&pdev->dev, PTR_ERR(rk_phy->phy_rst),
				     "missing phy property for reset controller\n");

	rk_phy->clk_pciephy_ref = devm_clk_get_enabled(dev, "refclk");
	if (IS_ERR(rk_phy->clk_pciephy_ref))
		return dev_err_probe(&pdev->dev, PTR_ERR(rk_phy->clk_pciephy_ref),
				     "failed to get phyclk\n");

	/* parse #phy-cells to see if it's legacy PHY model */
	if (of_property_read_u32(dev->of_node, "#phy-cells", &phy_num))
		return -ENOENT;

	phy_num = (phy_num == 0) ? 1 : PHY_MAX_LANE_NUM;
	dev_dbg(dev, "phy number is %d\n", phy_num);

	for (i = 0; i < phy_num; i++) {
		rk_phy->phys[i].phy = devm_phy_create(dev, dev->of_node, &ops);
		if (IS_ERR(rk_phy->phys[i].phy)) {
			dev_err(dev, "failed to create PHY%d\n", i);
			return PTR_ERR(rk_phy->phys[i].phy);
		}
		rk_phy->phys[i].index = i;
		phy_set_drvdata(rk_phy->phys[i].phy, &rk_phy->phys[i]);
	}

	platform_set_drvdata(pdev, rk_phy);
	phy_provider = devm_of_phy_provider_register(dev,
					rockchip_pcie_phy_of_xlate);

	return PTR_ERR_OR_ZERO(phy_provider);
}

static struct platform_driver rockchip_pcie_driver = {
	.probe		= rockchip_pcie_phy_probe,
	.driver		= {
		.name	= "rockchip-pcie-phy",
		.of_match_table = rockchip_pcie_phy_dt_ids,
	},
};

module_platform_driver(rockchip_pcie_driver);

MODULE_AUTHOR("Shawn Lin <shawn.lin@rock-chips.com>");
MODULE_DESCRIPTION("Rockchip PCIe PHY driver");
MODULE_LICENSE("GPL v2");