// SPDX-License-Identifier: GPL-2.0
//
// Secure Digital Host Controller
//
// Copyright (C) 2018 Spreadtrum, Inc.
// Author: Chunyan Zhang <chunyan.zhang@unisoc.com>

#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>

#include "sdhci-pltfm.h"

/* SDHCI_ARGUMENT2 register high 16bit */
#define SDHCI_SPRD_ARG2_STUFF		GENMASK(31, 16)

#define SDHCI_SPRD_REG_32_DLL_DLY_OFFSET	0x208
#define  SDHCIBSPRD_IT_WR_DLY_INV		BIT(5)
#define  SDHCI_SPRD_BIT_CMD_DLY_INV		BIT(13)
#define  SDHCI_SPRD_BIT_POSRD_DLY_INV		BIT(21)
#define  SDHCI_SPRD_BIT_NEGRD_DLY_INV		BIT(29)

#define SDHCI_SPRD_REG_32_BUSY_POSI		0x250
#define  SDHCI_SPRD_BIT_OUTR_CLK_AUTO_EN	BIT(25)
#define  SDHCI_SPRD_BIT_INNR_CLK_AUTO_EN	BIT(24)

#define SDHCI_SPRD_REG_DEBOUNCE		0x28C
#define  SDHCI_SPRD_BIT_DLL_BAK		BIT(0)
#define  SDHCI_SPRD_BIT_DLL_VAL		BIT(1)

#define  SDHCI_SPRD_INT_SIGNAL_MASK	0x1B7F410B

/* SDHCI_HOST_CONTROL2 */
#define  SDHCI_SPRD_CTRL_HS200		0x0005
#define  SDHCI_SPRD_CTRL_HS400		0x0006

/*
 * According to the standard specification, BIT(3) of SDHCI_SOFTWARE_RESET is
 * reserved, and only used on Spreadtrum's design, the hardware cannot work
 * if this bit is cleared.
 * 1 : normal work
 * 0 : hardware reset
 */
#define  SDHCI_HW_RESET_CARD		BIT(3)

#define SDHCI_SPRD_MAX_CUR		0xFFFFFF
#define SDHCI_SPRD_CLK_MAX_DIV		1023

#define SDHCI_SPRD_CLK_DEF_RATE		26000000

struct sdhci_sprd_host {
	u32 version;
	struct clk *clk_sdio;
	struct clk *clk_enable;
	u32 base_rate;
	int flags; /* backup of host attribute */
};

#define TO_SPRD_HOST(host) sdhci_pltfm_priv(sdhci_priv(host))

static void sdhci_sprd_init_config(struct sdhci_host *host)
{
	u16 val;

	/* set dll backup mode */
	val = sdhci_readl(host, SDHCI_SPRD_REG_DEBOUNCE);
	val |= SDHCI_SPRD_BIT_DLL_BAK | SDHCI_SPRD_BIT_DLL_VAL;
	sdhci_writel(host, val, SDHCI_SPRD_REG_DEBOUNCE);
}

static inline u32 sdhci_sprd_readl(struct sdhci_host *host, int reg)
{
	if (unlikely(reg == SDHCI_MAX_CURRENT))
		return SDHCI_SPRD_MAX_CUR;

	return readl_relaxed(host->ioaddr + reg);
}

static inline void sdhci_sprd_writel(struct sdhci_host *host, u32 val, int reg)
{
	/* SDHCI_MAX_CURRENT is reserved on Spreadtrum's platform */
	if (unlikely(reg == SDHCI_MAX_CURRENT))
		return;

	if (unlikely(reg == SDHCI_SIGNAL_ENABLE || reg == SDHCI_INT_ENABLE))
		val = val & SDHCI_SPRD_INT_SIGNAL_MASK;

	writel_relaxed(val, host->ioaddr + reg);
}

static inline void sdhci_sprd_writew(struct sdhci_host *host, u16 val, int reg)
{
	/* SDHCI_BLOCK_COUNT is Read Only on Spreadtrum's platform */
	if (unlikely(reg == SDHCI_BLOCK_COUNT))
		return;

	writew_relaxed(val, host->ioaddr + reg);
}

static inline void sdhci_sprd_writeb(struct sdhci_host *host, u8 val, int reg)
{
	/*
	 * Since BIT(3) of SDHCI_SOFTWARE_RESET is reserved according to the
	 * standard specification, sdhci_reset() write this register directly
	 * without checking other reserved bits, that will clear BIT(3) which
	 * is defined as hardware reset on Spreadtrum's platform and clearing
	 * it by mistake will lead the card not work. So here we need to work
	 * around it.
	 */
	if (unlikely(reg == SDHCI_SOFTWARE_RESET)) {
		if (readb_relaxed(host->ioaddr + reg) & SDHCI_HW_RESET_CARD)
			val |= SDHCI_HW_RESET_CARD;
	}

	writeb_relaxed(val, host->ioaddr + reg);
}

static inline void sdhci_sprd_sd_clk_off(struct sdhci_host *host)
{
	u16 ctrl = sdhci_readw(host, SDHCI_CLOCK_CONTROL);

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

static inline void
sdhci_sprd_set_dll_invert(struct sdhci_host *host, u32 mask, bool en)
{
	u32 dll_dly_offset;

	dll_dly_offset = sdhci_readl(host, SDHCI_SPRD_REG_32_DLL_DLY_OFFSET);
	if (en)
		dll_dly_offset |= mask;
	else
		dll_dly_offset &= ~mask;
	sdhci_writel(host, dll_dly_offset, SDHCI_SPRD_REG_32_DLL_DLY_OFFSET);
}

static inline u32 sdhci_sprd_calc_div(u32 base_clk, u32 clk)
{
	u32 div;

	/* select 2x clock source */
	if (base_clk <= clk * 2)
		return 0;

	div = (u32) (base_clk / (clk * 2));

	if ((base_clk / div) > (clk * 2))
		div++;

	if (div > SDHCI_SPRD_CLK_MAX_DIV)
		div = SDHCI_SPRD_CLK_MAX_DIV;

	if (div % 2)
		div = (div + 1) / 2;
	else
		div = div / 2;

	return div;
}

static inline void _sdhci_sprd_set_clock(struct sdhci_host *host,
					unsigned int clk)
{
	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);
	u32 div, val, mask;

	div = sdhci_sprd_calc_div(sprd_host->base_rate, clk);

	clk |= ((div & 0x300) >> 2) | ((div & 0xFF) << 8);
	sdhci_enable_clk(host, clk);

	/* enable auto gate sdhc_enable_auto_gate */
	val = sdhci_readl(host, SDHCI_SPRD_REG_32_BUSY_POSI);
	mask = SDHCI_SPRD_BIT_OUTR_CLK_AUTO_EN |
	       SDHCI_SPRD_BIT_INNR_CLK_AUTO_EN;
	if (mask != (val & mask)) {
		val |= mask;
		sdhci_writel(host, val, SDHCI_SPRD_REG_32_BUSY_POSI);
	}
}

static void sdhci_sprd_set_clock(struct sdhci_host *host, unsigned int clock)
{
	bool en = false;

	if (clock == 0) {
		sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
	} else if (clock != host->clock) {
		sdhci_sprd_sd_clk_off(host);
		_sdhci_sprd_set_clock(host, clock);

		if (clock <= 400000)
			en = true;
		sdhci_sprd_set_dll_invert(host, SDHCI_SPRD_BIT_CMD_DLY_INV |
					  SDHCI_SPRD_BIT_POSRD_DLY_INV, en);
	} else {
		_sdhci_sprd_set_clock(host, clock);
	}
}

static unsigned int sdhci_sprd_get_max_clock(struct sdhci_host *host)
{
	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);

	return clk_round_rate(sprd_host->clk_sdio, ULONG_MAX);
}

static unsigned int sdhci_sprd_get_min_clock(struct sdhci_host *host)
{
	return 400000;
}

static void sdhci_sprd_set_uhs_signaling(struct sdhci_host *host,
					 unsigned int timing)
{
	u16 ctrl_2;

	if (timing == host->timing)
		return;

	ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
	/* Select Bus Speed Mode for host */
	ctrl_2 &= ~SDHCI_CTRL_UHS_MASK;
	switch (timing) {
	case MMC_TIMING_UHS_SDR12:
		ctrl_2 |= SDHCI_CTRL_UHS_SDR12;
		break;
	case MMC_TIMING_MMC_HS:
	case MMC_TIMING_SD_HS:
	case MMC_TIMING_UHS_SDR25:
		ctrl_2 |= SDHCI_CTRL_UHS_SDR25;
		break;
	case MMC_TIMING_UHS_SDR50:
		ctrl_2 |= SDHCI_CTRL_UHS_SDR50;
		break;
	case MMC_TIMING_UHS_SDR104:
		ctrl_2 |= SDHCI_CTRL_UHS_SDR104;
		break;
	case MMC_TIMING_UHS_DDR50:
	case MMC_TIMING_MMC_DDR52:
		ctrl_2 |= SDHCI_CTRL_UHS_DDR50;
		break;
	case MMC_TIMING_MMC_HS200:
		ctrl_2 |= SDHCI_SPRD_CTRL_HS200;
		break;
	case MMC_TIMING_MMC_HS400:
		ctrl_2 |= SDHCI_SPRD_CTRL_HS400;
		break;
	default:
		break;
	}

	sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
}

static void sdhci_sprd_hw_reset(struct sdhci_host *host)
{
	int val;

	/*
	 * Note: don't use sdhci_writeb() API here since it is redirected to
	 * sdhci_sprd_writeb() in which we have a workaround for
	 * SDHCI_SOFTWARE_RESET which would make bit SDHCI_HW_RESET_CARD can
	 * not be cleared.
	 */
	val = readb_relaxed(host->ioaddr + SDHCI_SOFTWARE_RESET);
	val &= ~SDHCI_HW_RESET_CARD;
	writeb_relaxed(val, host->ioaddr + SDHCI_SOFTWARE_RESET);
	/* wait for 10 us */
	usleep_range(10, 20);

	val |= SDHCI_HW_RESET_CARD;
	writeb_relaxed(val, host->ioaddr + SDHCI_SOFTWARE_RESET);
	usleep_range(300, 500);
}

static struct sdhci_ops sdhci_sprd_ops = {
	.read_l = sdhci_sprd_readl,
	.write_l = sdhci_sprd_writel,
	.write_b = sdhci_sprd_writeb,
	.set_clock = sdhci_sprd_set_clock,
	.get_max_clock = sdhci_sprd_get_max_clock,
	.get_min_clock = sdhci_sprd_get_min_clock,
	.set_bus_width = sdhci_set_bus_width,
	.reset = sdhci_reset,
	.set_uhs_signaling = sdhci_sprd_set_uhs_signaling,
	.hw_reset = sdhci_sprd_hw_reset,
};

static void sdhci_sprd_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
	struct sdhci_host *host = mmc_priv(mmc);
	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);

	host->flags |= sprd_host->flags & SDHCI_AUTO_CMD23;

	/*
	 * From version 4.10 onward, ARGUMENT2 register is also as 32-bit
	 * block count register which doesn't support stuff bits of
	 * CMD23 argument on Spreadtrum's sd host controller.
	 */
	if (host->version >= SDHCI_SPEC_410 &&
	    mrq->sbc && (mrq->sbc->arg & SDHCI_SPRD_ARG2_STUFF) &&
	    (host->flags & SDHCI_AUTO_CMD23))
		host->flags &= ~SDHCI_AUTO_CMD23;

	sdhci_request(mmc, mrq);
}

static const struct sdhci_pltfm_data sdhci_sprd_pdata = {
	.quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK,
	.quirks2 = SDHCI_QUIRK2_BROKEN_HS200 |
		   SDHCI_QUIRK2_USE_32BIT_BLK_CNT,
	.ops = &sdhci_sprd_ops,
};

static int sdhci_sprd_probe(struct platform_device *pdev)
{
	struct sdhci_host *host;
	struct sdhci_sprd_host *sprd_host;
	struct clk *clk;
	int ret = 0;

	host = sdhci_pltfm_init(pdev, &sdhci_sprd_pdata, sizeof(*sprd_host));
	if (IS_ERR(host))
		return PTR_ERR(host);

	host->dma_mask = DMA_BIT_MASK(64);
	pdev->dev.dma_mask = &host->dma_mask;
	host->mmc_host_ops.request = sdhci_sprd_request;

	host->mmc->caps = MMC_CAP_SD_HIGHSPEED | MMC_CAP_MMC_HIGHSPEED |
		MMC_CAP_ERASE | MMC_CAP_CMD23;
	ret = mmc_of_parse(host->mmc);
	if (ret)
		goto pltfm_free;

	sprd_host = TO_SPRD_HOST(host);

	clk = devm_clk_get(&pdev->dev, "sdio");
	if (IS_ERR(clk)) {
		ret = PTR_ERR(clk);
		goto pltfm_free;
	}
	sprd_host->clk_sdio = clk;
	sprd_host->base_rate = clk_get_rate(sprd_host->clk_sdio);
	if (!sprd_host->base_rate)
		sprd_host->base_rate = SDHCI_SPRD_CLK_DEF_RATE;

	clk = devm_clk_get(&pdev->dev, "enable");
	if (IS_ERR(clk)) {
		ret = PTR_ERR(clk);
		goto pltfm_free;
	}
	sprd_host->clk_enable = clk;

	ret = clk_prepare_enable(sprd_host->clk_sdio);
	if (ret)
		goto pltfm_free;

	clk_prepare_enable(sprd_host->clk_enable);
	if (ret)
		goto clk_disable;

	sdhci_sprd_init_config(host);
	host->version = sdhci_readw(host, SDHCI_HOST_VERSION);
	sprd_host->version = ((host->version & SDHCI_VENDOR_VER_MASK) >>
			       SDHCI_VENDOR_VER_SHIFT);

	pm_runtime_get_noresume(&pdev->dev);
	pm_runtime_set_active(&pdev->dev);
	pm_runtime_enable(&pdev->dev);
	pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
	pm_runtime_use_autosuspend(&pdev->dev);
	pm_suspend_ignore_children(&pdev->dev, 1);

	sdhci_enable_v4_mode(host);

	ret = sdhci_setup_host(host);
	if (ret)
		goto pm_runtime_disable;

	sprd_host->flags = host->flags;

	ret = __sdhci_add_host(host);
	if (ret)
		goto err_cleanup_host;

	pm_runtime_mark_last_busy(&pdev->dev);
	pm_runtime_put_autosuspend(&pdev->dev);

	return 0;

err_cleanup_host:
	sdhci_cleanup_host(host);

pm_runtime_disable:
	pm_runtime_disable(&pdev->dev);
	pm_runtime_set_suspended(&pdev->dev);

	clk_disable_unprepare(sprd_host->clk_enable);

clk_disable:
	clk_disable_unprepare(sprd_host->clk_sdio);

pltfm_free:
	sdhci_pltfm_free(pdev);
	return ret;
}

static int sdhci_sprd_remove(struct platform_device *pdev)
{
	struct sdhci_host *host = platform_get_drvdata(pdev);
	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);
	struct mmc_host *mmc = host->mmc;

	mmc_remove_host(mmc);
	clk_disable_unprepare(sprd_host->clk_sdio);
	clk_disable_unprepare(sprd_host->clk_enable);

	mmc_free_host(mmc);

	return 0;
}

static const struct of_device_id sdhci_sprd_of_match[] = {
	{ .compatible = "sprd,sdhci-r11", },
	{ }
};
MODULE_DEVICE_TABLE(of, sdhci_sprd_of_match);

#ifdef CONFIG_PM
static int sdhci_sprd_runtime_suspend(struct device *dev)
{
	struct sdhci_host *host = dev_get_drvdata(dev);
	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);

	sdhci_runtime_suspend_host(host);

	clk_disable_unprepare(sprd_host->clk_sdio);
	clk_disable_unprepare(sprd_host->clk_enable);

	return 0;
}

static int sdhci_sprd_runtime_resume(struct device *dev)
{
	struct sdhci_host *host = dev_get_drvdata(dev);
	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);
	int ret;

	ret = clk_prepare_enable(sprd_host->clk_enable);
	if (ret)
		return ret;

	ret = clk_prepare_enable(sprd_host->clk_sdio);
	if (ret) {
		clk_disable_unprepare(sprd_host->clk_enable);
		return ret;
	}

	sdhci_runtime_resume_host(host);

	return 0;
}
#endif

static const struct dev_pm_ops sdhci_sprd_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
				pm_runtime_force_resume)
	SET_RUNTIME_PM_OPS(sdhci_sprd_runtime_suspend,
			   sdhci_sprd_runtime_resume, NULL)
};

static struct platform_driver sdhci_sprd_driver = {
	.probe = sdhci_sprd_probe,
	.remove = sdhci_sprd_remove,
	.driver = {
		.name = "sdhci_sprd_r11",
		.of_match_table = of_match_ptr(sdhci_sprd_of_match),
		.pm = &sdhci_sprd_pm_ops,
	},
};
module_platform_driver(sdhci_sprd_driver);

MODULE_DESCRIPTION("Spreadtrum sdio host controller r11 driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:sdhci-sprd-r11");