// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2024 Nuvoton Technology Corp.
 *
 * Author: Shan-Chun Hung <shanchun1218@gmail.com>
 */

#include <linux/align.h>
#include <linux/array_size.h>
#include <linux/bits.h>
#include <linux/build_bug.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/dev_printk.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/math.h>
#include <linux/mfd/syscon.h>
#include <linux/minmax.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/reset.h>
#include <linux/sizes.h>
#include <linux/types.h>

#include "sdhci-pltfm.h"
#include "sdhci.h"

#define MA35_SYS_MISCFCR0	0x070
#define MA35_SDHCI_MSHCCTL	0x508
#define MA35_SDHCI_MBIUCTL	0x510

#define MA35_SDHCI_CMD_CONFLICT_CHK	BIT(0)
#define MA35_SDHCI_INCR_MSK		GENMASK(3, 0)
#define MA35_SDHCI_INCR16		BIT(3)
#define MA35_SDHCI_INCR8		BIT(2)

struct ma35_priv {
	struct reset_control	*rst;
	struct pinctrl		*pinctrl;
	struct pinctrl_state	*pins_uhs;
	struct pinctrl_state	*pins_default;
};

struct ma35_restore_data {
	u32	reg;
	u32	width;
};

static const struct ma35_restore_data restore_data[] = {
	{ SDHCI_CLOCK_CONTROL,		sizeof(u32)},
	{ SDHCI_BLOCK_SIZE,		sizeof(u32)},
	{ SDHCI_INT_ENABLE,		sizeof(u32)},
	{ SDHCI_SIGNAL_ENABLE,		sizeof(u32)},
	{ SDHCI_AUTO_CMD_STATUS,	sizeof(u32)},
	{ SDHCI_HOST_CONTROL,		sizeof(u32)},
	{ SDHCI_TIMEOUT_CONTROL,	sizeof(u8) },
	{ MA35_SDHCI_MSHCCTL,		sizeof(u16)},
	{ MA35_SDHCI_MBIUCTL,		sizeof(u16)},
};

/*
 * If DMA addr spans 128MB boundary, we split the DMA transfer into two
 * so that each DMA transfer doesn't exceed the boundary.
 */
static void ma35_adma_write_desc(struct sdhci_host *host, void **desc, dma_addr_t addr, int len,
				 unsigned int cmd)
{
	int tmplen, offset;

	if (likely(!len || (ALIGN(addr, SZ_128M) == ALIGN(addr + len - 1, SZ_128M)))) {
		sdhci_adma_write_desc(host, desc, addr, len, cmd);
		return;
	}

	offset = addr & (SZ_128M - 1);
	tmplen = SZ_128M - offset;
	sdhci_adma_write_desc(host, desc, addr, tmplen, cmd);

	addr += tmplen;
	len -= tmplen;
	sdhci_adma_write_desc(host, desc, addr, len, cmd);
}

static void ma35_set_clock(struct sdhci_host *host, unsigned int clock)
{
	u32 ctl;

	/*
	 * If the clock frequency exceeds MMC_HIGH_52_MAX_DTR,
	 * disable command conflict check.
	 */
	ctl = sdhci_readw(host, MA35_SDHCI_MSHCCTL);
	if (clock > MMC_HIGH_52_MAX_DTR)
		ctl &= ~MA35_SDHCI_CMD_CONFLICT_CHK;
	else
		ctl |= MA35_SDHCI_CMD_CONFLICT_CHK;
	sdhci_writew(host, ctl, MA35_SDHCI_MSHCCTL);

	sdhci_set_clock(host, clock);
}

static int ma35_start_signal_voltage_switch(struct mmc_host *mmc, struct mmc_ios *ios)
{
	struct sdhci_host *host = mmc_priv(mmc);
	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
	struct ma35_priv *priv = sdhci_pltfm_priv(pltfm_host);

	switch (ios->signal_voltage) {
	case MMC_SIGNAL_VOLTAGE_180:
		if (!IS_ERR(priv->pinctrl) && !IS_ERR(priv->pins_uhs))
			pinctrl_select_state(priv->pinctrl, priv->pins_uhs);
		break;
	case MMC_SIGNAL_VOLTAGE_330:
		if (!IS_ERR(priv->pinctrl) && !IS_ERR(priv->pins_default))
			pinctrl_select_state(priv->pinctrl, priv->pins_default);
		break;
	default:
		dev_err(mmc_dev(host->mmc), "Unsupported signal voltage!\n");
		return -EINVAL;
	}

	return sdhci_start_signal_voltage_switch(mmc, ios);
}

static void ma35_voltage_switch(struct sdhci_host *host)
{
	/* Wait for 5ms after set 1.8V signal enable bit */
	fsleep(5000);
}

static int ma35_execute_tuning(struct mmc_host *mmc, u32 opcode)
{
	struct sdhci_host *host = mmc_priv(mmc);
	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
	struct ma35_priv *priv = sdhci_pltfm_priv(pltfm_host);
	int idx;
	u32 regs[ARRAY_SIZE(restore_data)] = {};

	/*
	 * Limitations require a reset of SD/eMMC before tuning and
	 * saving the registers before resetting, then restoring
	 * after the reset.
	 */
	for (idx = 0; idx < ARRAY_SIZE(restore_data); idx++) {
		if (restore_data[idx].width == sizeof(u32))
			regs[idx] = sdhci_readl(host, restore_data[idx].reg);
		else if (restore_data[idx].width == sizeof(u16))
			regs[idx] = sdhci_readw(host, restore_data[idx].reg);
		else if (restore_data[idx].width == sizeof(u8))
			regs[idx] = sdhci_readb(host, restore_data[idx].reg);
	}

	reset_control_assert(priv->rst);
	reset_control_deassert(priv->rst);

	for (idx = 0; idx < ARRAY_SIZE(restore_data); idx++) {
		if (restore_data[idx].width == sizeof(u32))
			sdhci_writel(host, regs[idx], restore_data[idx].reg);
		else if (restore_data[idx].width == sizeof(u16))
			sdhci_writew(host, regs[idx], restore_data[idx].reg);
		else if (restore_data[idx].width == sizeof(u8))
			sdhci_writeb(host, regs[idx], restore_data[idx].reg);
	}

	return sdhci_execute_tuning(mmc, opcode);
}

static const struct sdhci_ops sdhci_ma35_ops = {
	.set_clock		= ma35_set_clock,
	.set_bus_width		= sdhci_set_bus_width,
	.set_uhs_signaling	= sdhci_set_uhs_signaling,
	.get_max_clock		= sdhci_pltfm_clk_get_max_clock,
	.reset			= sdhci_reset,
	.adma_write_desc	= ma35_adma_write_desc,
	.voltage_switch		= ma35_voltage_switch,
};

static const struct sdhci_pltfm_data sdhci_ma35_pdata = {
	.ops = &sdhci_ma35_ops,
	.quirks = SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
	.quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN | SDHCI_QUIRK2_BROKEN_DDR50 |
		   SDHCI_QUIRK2_ACMD23_BROKEN,
};

static int ma35_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct sdhci_pltfm_host *pltfm_host;
	struct sdhci_host *host;
	struct ma35_priv *priv;
	int err;
	u32 extra, ctl;

	host = sdhci_pltfm_init(pdev, &sdhci_ma35_pdata, sizeof(struct ma35_priv));
	if (IS_ERR(host))
		return PTR_ERR(host);

	/* Extra adma table cnt for cross 128M boundary handling. */
	extra = DIV_ROUND_UP_ULL(dma_get_required_mask(dev), SZ_128M);
	extra = min(extra, SDHCI_MAX_SEGS);

	host->adma_table_cnt += extra;
	pltfm_host = sdhci_priv(host);
	priv = sdhci_pltfm_priv(pltfm_host);

	pltfm_host->clk = devm_clk_get_optional_enabled(dev, NULL);
	if (IS_ERR(pltfm_host->clk)) {
		err = dev_err_probe(dev, PTR_ERR(pltfm_host->clk), "failed to get clk\n");
		goto err_sdhci;
	}

	err = mmc_of_parse(host->mmc);
	if (err)
		goto err_sdhci;

	priv->rst = devm_reset_control_get_exclusive(dev, NULL);
	if (IS_ERR(priv->rst)) {
		err = dev_err_probe(dev, PTR_ERR(priv->rst), "failed to get reset control\n");
		goto err_sdhci;
	}

	sdhci_get_of_property(pdev);

	priv->pinctrl = devm_pinctrl_get(dev);
	if (!IS_ERR(priv->pinctrl)) {
		priv->pins_default = pinctrl_lookup_state(priv->pinctrl, "default");
		priv->pins_uhs = pinctrl_lookup_state(priv->pinctrl, "state_uhs");
		pinctrl_select_state(priv->pinctrl, priv->pins_default);
	}

	if (!(host->quirks2 & SDHCI_QUIRK2_NO_1_8_V)) {
		struct regmap	*regmap;
		u32		reg;

		regmap = syscon_regmap_lookup_by_phandle(dev_of_node(dev), "nuvoton,sys");
		if (!IS_ERR(regmap)) {
			/* Enable SDHCI voltage stable for 1.8V */
			regmap_read(regmap, MA35_SYS_MISCFCR0, &reg);
			reg |= BIT(17);
			regmap_write(regmap, MA35_SYS_MISCFCR0, reg);
		}

		host->mmc_host_ops.start_signal_voltage_switch =
					ma35_start_signal_voltage_switch;
	}

	host->mmc_host_ops.execute_tuning = ma35_execute_tuning;

	err = sdhci_add_host(host);
	if (err)
		goto err_sdhci;

	/*
	 * Split data into chunks of 16 or 8 bytes for transmission.
	 * Each chunk transfer is guaranteed to be uninterrupted on the bus.
	 * This likely corresponds to the AHB bus DMA burst size.
	 */
	ctl = sdhci_readw(host, MA35_SDHCI_MBIUCTL);
	ctl &= ~MA35_SDHCI_INCR_MSK;
	ctl |= MA35_SDHCI_INCR16 | MA35_SDHCI_INCR8;
	sdhci_writew(host, ctl, MA35_SDHCI_MBIUCTL);

	return 0;

err_sdhci:
	sdhci_pltfm_free(pdev);
	return err;
}

static void ma35_disable_card_clk(struct sdhci_host *host)
{
	u16 ctrl;

	ctrl = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
	if (ctrl & SDHCI_CLOCK_CARD_EN) {
		ctrl &= ~SDHCI_CLOCK_CARD_EN;
		sdhci_writew(host, ctrl, SDHCI_CLOCK_CONTROL);
	}
}

static void ma35_remove(struct platform_device *pdev)
{
	struct sdhci_host *host = platform_get_drvdata(pdev);

	sdhci_remove_host(host, 0);
	ma35_disable_card_clk(host);
	sdhci_pltfm_free(pdev);
}

static const struct of_device_id sdhci_ma35_dt_ids[] = {
	{ .compatible = "nuvoton,ma35d1-sdhci" },
	{}
};

static struct platform_driver sdhci_ma35_driver = {
	.driver	= {
		.name	= "sdhci-ma35",
		.of_match_table = sdhci_ma35_dt_ids,
	},
	.probe	= ma35_probe,
	.remove = ma35_remove,
};
module_platform_driver(sdhci_ma35_driver);

MODULE_DESCRIPTION("SDHCI platform driver for Nuvoton MA35");
MODULE_AUTHOR("Shan-Chun Hung <shanchun1218@gmail.com>");
MODULE_LICENSE("GPL");