/*
 * Exynos Specific Extensions for Synopsys DW Multimedia Card Interface driver
 *
 * Copyright (C) 2012, Samsung Electronics Co., Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/mmc/host.h>
#include <linux/mmc/dw_mmc.h>
#include <linux/mmc/mmc.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/slab.h>

#include "dw_mmc.h"
#include "dw_mmc-pltfm.h"

#define NUM_PINS(x)			(x + 2)

#define SDMMC_CLKSEL			0x09C
#define SDMMC_CLKSEL_CCLK_SAMPLE(x)	(((x) & 7) << 0)
#define SDMMC_CLKSEL_CCLK_DRIVE(x)	(((x) & 7) << 16)
#define SDMMC_CLKSEL_CCLK_DIVIDER(x)	(((x) & 7) << 24)
#define SDMMC_CLKSEL_GET_DRV_WD3(x)	(((x) >> 16) & 0x7)
#define SDMMC_CLKSEL_TIMING(x, y, z)	(SDMMC_CLKSEL_CCLK_SAMPLE(x) |	\
					SDMMC_CLKSEL_CCLK_DRIVE(y) |	\
					SDMMC_CLKSEL_CCLK_DIVIDER(z))
#define SDMMC_CLKSEL_WAKEUP_INT		BIT(11)

#define EXYNOS4210_FIXED_CIU_CLK_DIV	2
#define EXYNOS4412_FIXED_CIU_CLK_DIV	4

/* Block number in eMMC */
#define DWMCI_BLOCK_NUM		0xFFFFFFFF

#define SDMMC_EMMCP_BASE	0x1000
#define SDMMC_MPSECURITY	(SDMMC_EMMCP_BASE + 0x0010)
#define SDMMC_MPSBEGIN0		(SDMMC_EMMCP_BASE + 0x0200)
#define SDMMC_MPSEND0		(SDMMC_EMMCP_BASE + 0x0204)
#define SDMMC_MPSCTRL0		(SDMMC_EMMCP_BASE + 0x020C)

/* SMU control bits */
#define DWMCI_MPSCTRL_SECURE_READ_BIT		BIT(7)
#define DWMCI_MPSCTRL_SECURE_WRITE_BIT		BIT(6)
#define DWMCI_MPSCTRL_NON_SECURE_READ_BIT	BIT(5)
#define DWMCI_MPSCTRL_NON_SECURE_WRITE_BIT	BIT(4)
#define DWMCI_MPSCTRL_USE_FUSE_KEY		BIT(3)
#define DWMCI_MPSCTRL_ECB_MODE			BIT(2)
#define DWMCI_MPSCTRL_ENCRYPTION		BIT(1)
#define DWMCI_MPSCTRL_VALID			BIT(0)

#define EXYNOS_CCLKIN_MIN	50000000	/* unit: HZ */

/* Variations in Exynos specific dw-mshc controller */
enum dw_mci_exynos_type {
	DW_MCI_TYPE_EXYNOS4210,
	DW_MCI_TYPE_EXYNOS4412,
	DW_MCI_TYPE_EXYNOS5250,
	DW_MCI_TYPE_EXYNOS5420,
	DW_MCI_TYPE_EXYNOS5420_SMU,
};

/* Exynos implementation specific driver private data */
struct dw_mci_exynos_priv_data {
	enum dw_mci_exynos_type		ctrl_type;
	u8				ciu_div;
	u32				sdr_timing;
	u32				ddr_timing;
	u32				cur_speed;
};

static struct dw_mci_exynos_compatible {
	char				*compatible;
	enum dw_mci_exynos_type		ctrl_type;
} exynos_compat[] = {
	{
		.compatible	= "samsung,exynos4210-dw-mshc",
		.ctrl_type	= DW_MCI_TYPE_EXYNOS4210,
	}, {
		.compatible	= "samsung,exynos4412-dw-mshc",
		.ctrl_type	= DW_MCI_TYPE_EXYNOS4412,
	}, {
		.compatible	= "samsung,exynos5250-dw-mshc",
		.ctrl_type	= DW_MCI_TYPE_EXYNOS5250,
	}, {
		.compatible	= "samsung,exynos5420-dw-mshc",
		.ctrl_type	= DW_MCI_TYPE_EXYNOS5420,
	}, {
		.compatible	= "samsung,exynos5420-dw-mshc-smu",
		.ctrl_type	= DW_MCI_TYPE_EXYNOS5420_SMU,
	},
};

static int dw_mci_exynos_priv_init(struct dw_mci *host)
{
	struct dw_mci_exynos_priv_data *priv = host->priv;

	if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS5420_SMU) {
		mci_writel(host, MPSBEGIN0, 0);
		mci_writel(host, MPSEND0, DWMCI_BLOCK_NUM);
		mci_writel(host, MPSCTRL0, DWMCI_MPSCTRL_SECURE_WRITE_BIT |
			   DWMCI_MPSCTRL_NON_SECURE_READ_BIT |
			   DWMCI_MPSCTRL_VALID |
			   DWMCI_MPSCTRL_NON_SECURE_WRITE_BIT);
	}

	return 0;
}

static int dw_mci_exynos_setup_clock(struct dw_mci *host)
{
	struct dw_mci_exynos_priv_data *priv = host->priv;
	unsigned long rate = clk_get_rate(host->ciu_clk);

	host->bus_hz = rate / (priv->ciu_div + 1);
	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int dw_mci_exynos_suspend(struct device *dev)
{
	struct dw_mci *host = dev_get_drvdata(dev);

	return dw_mci_suspend(host);
}

static int dw_mci_exynos_resume(struct device *dev)
{
	struct dw_mci *host = dev_get_drvdata(dev);

	dw_mci_exynos_priv_init(host);
	return dw_mci_resume(host);
}

/**
 * dw_mci_exynos_resume_noirq - Exynos-specific resume code
 *
 * On exynos5420 there is a silicon errata that will sometimes leave the
 * WAKEUP_INT bit in the CLKSEL register asserted.  This bit is 1 to indicate
 * that it fired and we can clear it by writing a 1 back.  Clear it to prevent
 * interrupts from going off constantly.
 *
 * We run this code on all exynos variants because it doesn't hurt.
 */

static int dw_mci_exynos_resume_noirq(struct device *dev)
{
	struct dw_mci *host = dev_get_drvdata(dev);
	u32 clksel;

	clksel = mci_readl(host, CLKSEL);
	if (clksel & SDMMC_CLKSEL_WAKEUP_INT)
		mci_writel(host, CLKSEL, clksel);

	return 0;
}
#else
#define dw_mci_exynos_suspend		NULL
#define dw_mci_exynos_resume		NULL
#define dw_mci_exynos_resume_noirq	NULL
#endif /* CONFIG_PM_SLEEP */

static void dw_mci_exynos_prepare_command(struct dw_mci *host, u32 *cmdr)
{
	/*
	 * Exynos4412 and Exynos5250 extends the use of CMD register with the
	 * use of bit 29 (which is reserved on standard MSHC controllers) for
	 * optionally bypassing the HOLD register for command and data. The
	 * HOLD register should be bypassed in case there is no phase shift
	 * applied on CMD/DATA that is sent to the card.
	 */
	if (SDMMC_CLKSEL_GET_DRV_WD3(mci_readl(host, CLKSEL)))
		*cmdr |= SDMMC_CMD_USE_HOLD_REG;
}

static void dw_mci_exynos_set_ios(struct dw_mci *host, struct mmc_ios *ios)
{
	struct dw_mci_exynos_priv_data *priv = host->priv;
	unsigned int wanted = ios->clock;
	unsigned long actual;
	u8 div = priv->ciu_div + 1;

	if (ios->timing == MMC_TIMING_UHS_DDR50) {
		mci_writel(host, CLKSEL, priv->ddr_timing);
		/* Should be double rate for DDR mode */
		if (ios->bus_width == MMC_BUS_WIDTH_8)
			wanted <<= 1;
	} else {
		mci_writel(host, CLKSEL, priv->sdr_timing);
	}

	/* Don't care if wanted clock is zero */
	if (!wanted)
		return;

	/* Guaranteed minimum frequency for cclkin */
	if (wanted < EXYNOS_CCLKIN_MIN)
		wanted = EXYNOS_CCLKIN_MIN;

	if (wanted != priv->cur_speed) {
		int ret = clk_set_rate(host->ciu_clk, wanted * div);
		if (ret)
			dev_warn(host->dev,
				"failed to set clk-rate %u error: %d\n",
				 wanted * div, ret);
		actual = clk_get_rate(host->ciu_clk);
		host->bus_hz = actual / div;
		priv->cur_speed = wanted;
		host->current_speed = 0;
	}
}

static int dw_mci_exynos_parse_dt(struct dw_mci *host)
{
	struct dw_mci_exynos_priv_data *priv;
	struct device_node *np = host->dev->of_node;
	u32 timing[2];
	u32 div = 0;
	int idx;
	int ret;

	priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
	if (!priv) {
		dev_err(host->dev, "mem alloc failed for private data\n");
		return -ENOMEM;
	}

	for (idx = 0; idx < ARRAY_SIZE(exynos_compat); idx++) {
		if (of_device_is_compatible(np, exynos_compat[idx].compatible))
			priv->ctrl_type = exynos_compat[idx].ctrl_type;
	}

	if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS4412)
		priv->ciu_div = EXYNOS4412_FIXED_CIU_CLK_DIV - 1;
	else if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS4210)
		priv->ciu_div = EXYNOS4210_FIXED_CIU_CLK_DIV - 1;
	else {
		of_property_read_u32(np, "samsung,dw-mshc-ciu-div", &div);
		priv->ciu_div = div;
	}

	ret = of_property_read_u32_array(np,
			"samsung,dw-mshc-sdr-timing", timing, 2);
	if (ret)
		return ret;

	priv->sdr_timing = SDMMC_CLKSEL_TIMING(timing[0], timing[1], div);

	ret = of_property_read_u32_array(np,
			"samsung,dw-mshc-ddr-timing", timing, 2);
	if (ret)
		return ret;

	priv->ddr_timing = SDMMC_CLKSEL_TIMING(timing[0], timing[1], div);
	host->priv = priv;
	return 0;
}

static inline u8 dw_mci_exynos_get_clksmpl(struct dw_mci *host)
{
	return SDMMC_CLKSEL_CCLK_SAMPLE(mci_readl(host, CLKSEL));
}

static inline void dw_mci_exynos_set_clksmpl(struct dw_mci *host, u8 sample)
{
	u32 clksel;
	clksel = mci_readl(host, CLKSEL);
	clksel = (clksel & ~0x7) | SDMMC_CLKSEL_CCLK_SAMPLE(sample);
	mci_writel(host, CLKSEL, clksel);
}

static inline u8 dw_mci_exynos_move_next_clksmpl(struct dw_mci *host)
{
	u32 clksel;
	u8 sample;

	clksel = mci_readl(host, CLKSEL);
	sample = (clksel + 1) & 0x7;
	clksel = (clksel & ~0x7) | sample;
	mci_writel(host, CLKSEL, clksel);
	return sample;
}

static s8 dw_mci_exynos_get_best_clksmpl(u8 candiates)
{
	const u8 iter = 8;
	u8 __c;
	s8 i, loc = -1;

	for (i = 0; i < iter; i++) {
		__c = ror8(candiates, i);
		if ((__c & 0xc7) == 0xc7) {
			loc = i;
			goto out;
		}
	}

	for (i = 0; i < iter; i++) {
		__c = ror8(candiates, i);
		if ((__c & 0x83) == 0x83) {
			loc = i;
			goto out;
		}
	}

out:
	return loc;
}

static int dw_mci_exynos_execute_tuning(struct dw_mci_slot *slot, u32 opcode,
					struct dw_mci_tuning_data *tuning_data)
{
	struct dw_mci *host = slot->host;
	struct mmc_host *mmc = slot->mmc;
	const u8 *blk_pattern = tuning_data->blk_pattern;
	u8 *blk_test;
	unsigned int blksz = tuning_data->blksz;
	u8 start_smpl, smpl, candiates = 0;
	s8 found = -1;
	int ret = 0;

	blk_test = kmalloc(blksz, GFP_KERNEL);
	if (!blk_test)
		return -ENOMEM;

	start_smpl = dw_mci_exynos_get_clksmpl(host);

	do {
		struct mmc_request mrq = {NULL};
		struct mmc_command cmd = {0};
		struct mmc_command stop = {0};
		struct mmc_data data = {0};
		struct scatterlist sg;

		cmd.opcode = opcode;
		cmd.arg = 0;
		cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;

		stop.opcode = MMC_STOP_TRANSMISSION;
		stop.arg = 0;
		stop.flags = MMC_RSP_R1B | MMC_CMD_AC;

		data.blksz = blksz;
		data.blocks = 1;
		data.flags = MMC_DATA_READ;
		data.sg = &sg;
		data.sg_len = 1;

		sg_init_one(&sg, blk_test, blksz);
		mrq.cmd = &cmd;
		mrq.stop = &stop;
		mrq.data = &data;
		host->mrq = &mrq;

		mci_writel(host, TMOUT, ~0);
		smpl = dw_mci_exynos_move_next_clksmpl(host);

		mmc_wait_for_req(mmc, &mrq);

		if (!cmd.error && !data.error) {
			if (!memcmp(blk_pattern, blk_test, blksz))
				candiates |= (1 << smpl);
		} else {
			dev_dbg(host->dev,
				"Tuning error: cmd.error:%d, data.error:%d\n",
				cmd.error, data.error);
		}
	} while (start_smpl != smpl);

	found = dw_mci_exynos_get_best_clksmpl(candiates);
	if (found >= 0)
		dw_mci_exynos_set_clksmpl(host, found);
	else
		ret = -EIO;

	kfree(blk_test);
	return ret;
}

/* Common capabilities of Exynos4/Exynos5 SoC */
static unsigned long exynos_dwmmc_caps[4] = {
	MMC_CAP_UHS_DDR50 | MMC_CAP_1_8V_DDR |
		MMC_CAP_8_BIT_DATA | MMC_CAP_CMD23,
	MMC_CAP_CMD23,
	MMC_CAP_CMD23,
	MMC_CAP_CMD23,
};

static const struct dw_mci_drv_data exynos_drv_data = {
	.caps			= exynos_dwmmc_caps,
	.init			= dw_mci_exynos_priv_init,
	.setup_clock		= dw_mci_exynos_setup_clock,
	.prepare_command	= dw_mci_exynos_prepare_command,
	.set_ios		= dw_mci_exynos_set_ios,
	.parse_dt		= dw_mci_exynos_parse_dt,
	.execute_tuning		= dw_mci_exynos_execute_tuning,
};

static const struct of_device_id dw_mci_exynos_match[] = {
	{ .compatible = "samsung,exynos4412-dw-mshc",
			.data = &exynos_drv_data, },
	{ .compatible = "samsung,exynos5250-dw-mshc",
			.data = &exynos_drv_data, },
	{ .compatible = "samsung,exynos5420-dw-mshc",
			.data = &exynos_drv_data, },
	{ .compatible = "samsung,exynos5420-dw-mshc-smu",
			.data = &exynos_drv_data, },
	{},
};
MODULE_DEVICE_TABLE(of, dw_mci_exynos_match);

static int dw_mci_exynos_probe(struct platform_device *pdev)
{
	const struct dw_mci_drv_data *drv_data;
	const struct of_device_id *match;

	match = of_match_node(dw_mci_exynos_match, pdev->dev.of_node);
	drv_data = match->data;
	return dw_mci_pltfm_register(pdev, drv_data);
}

const struct dev_pm_ops dw_mci_exynos_pmops = {
	SET_SYSTEM_SLEEP_PM_OPS(dw_mci_exynos_suspend, dw_mci_exynos_resume)
	.resume_noirq = dw_mci_exynos_resume_noirq,
	.thaw_noirq = dw_mci_exynos_resume_noirq,
	.restore_noirq = dw_mci_exynos_resume_noirq,
};

static struct platform_driver dw_mci_exynos_pltfm_driver = {
	.probe		= dw_mci_exynos_probe,
	.remove		= __exit_p(dw_mci_pltfm_remove),
	.driver		= {
		.name		= "dwmmc_exynos",
		.of_match_table	= dw_mci_exynos_match,
		.pm		= &dw_mci_exynos_pmops,
	},
};

module_platform_driver(dw_mci_exynos_pltfm_driver);

MODULE_DESCRIPTION("Samsung Specific DW-MSHC Driver Extension");
MODULE_AUTHOR("Thomas Abraham <thomas.ab@samsung.com");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:dwmmc-exynos");