/*
 * drivers/mmc/host/sdhci-msm.c - Qualcomm SDHCI Platform driver
 *
 * Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/regulator/consumer.h>
#include <linux/delay.h>
#include <linux/mmc/mmc.h>
#include <linux/slab.h>

#include "sdhci-pltfm.h"

#define CORE_HC_MODE            0x78
#define HC_MODE_EN              0x1
#define CORE_POWER              0x0
#define CORE_SW_RST             BIT(7)

#define MAX_PHASES              16
#define CORE_DLL_LOCK           BIT(7)
#define CORE_DLL_EN             BIT(16)
#define CORE_CDR_EN             BIT(17)
#define CORE_CK_OUT_EN          BIT(18)
#define CORE_CDR_EXT_EN         BIT(19)
#define CORE_DLL_PDN            BIT(29)
#define CORE_DLL_RST            BIT(30)
#define CORE_DLL_CONFIG         0x100
#define CORE_DLL_STATUS         0x108

#define CORE_VENDOR_SPEC        0x10c
#define CORE_CLK_PWRSAVE        BIT(1)

#define CDR_SELEXT_SHIFT        20
#define CDR_SELEXT_MASK         (0xf << CDR_SELEXT_SHIFT)
#define CMUX_SHIFT_PHASE_SHIFT  24
#define CMUX_SHIFT_PHASE_MASK   (7 << CMUX_SHIFT_PHASE_SHIFT)

static const u32 tuning_block_64[] = {
        0x00ff0fff, 0xccc3ccff, 0xffcc3cc3, 0xeffefffe,
        0xddffdfff, 0xfbfffbff, 0xff7fffbf, 0xefbdf777,
        0xf0fff0ff, 0x3cccfc0f, 0xcfcc33cc, 0xeeffefff,
        0xfdfffdff, 0xffbfffdf, 0xfff7ffbb, 0xde7b7ff7
};

static const u32 tuning_block_128[] = {
        0xff00ffff, 0x0000ffff, 0xccccffff, 0xcccc33cc,
        0xcc3333cc, 0xffffcccc, 0xffffeeff, 0xffeeeeff,
        0xffddffff, 0xddddffff, 0xbbffffff, 0xbbffffff,
        0xffffffbb, 0xffffff77, 0x77ff7777, 0xffeeddbb,
        0x00ffffff, 0x00ffffff, 0xccffff00, 0xcc33cccc,
        0x3333cccc, 0xffcccccc, 0xffeeffff, 0xeeeeffff,
        0xddffffff, 0xddffffff, 0xffffffdd, 0xffffffbb,
        0xffffbbbb, 0xffff77ff, 0xff7777ff, 0xeeddbb77
};

struct sdhci_msm_host {
        struct platform_device *pdev;
        void __iomem *core_mem; /* MSM SDCC mapped address */
        struct clk *clk;        /* main SD/MMC bus clock */
        struct clk *pclk;       /* SDHC peripheral bus clock */
        struct clk *bus_clk;    /* SDHC bus voter clock */
        struct mmc_host *mmc;
        struct sdhci_pltfm_data sdhci_msm_pdata;
};

/* Platform specific tuning */
static inline int msm_dll_poll_ck_out_en(struct sdhci_host *host, u8 poll)
{
        u32 wait_cnt = 50;
        u8 ck_out_en;
        struct mmc_host *mmc = host->mmc;

        /* Poll for CK_OUT_EN bit.  max. poll time = 50us */
        ck_out_en = !!(readl_relaxed(host->ioaddr + CORE_DLL_CONFIG) &
                        CORE_CK_OUT_EN);

        while (ck_out_en != poll) {
                if (--wait_cnt == 0) {
                        dev_err(mmc_dev(mmc), "%s: CK_OUT_EN bit is not %d\n",
                               mmc_hostname(mmc), poll);
                        return -ETIMEDOUT;
                }
                udelay(1);

                ck_out_en = !!(readl_relaxed(host->ioaddr + CORE_DLL_CONFIG) &
                                CORE_CK_OUT_EN);
        }

        return 0;
}

static int msm_config_cm_dll_phase(struct sdhci_host *host, u8 phase)
{
        int rc;
        static const u8 grey_coded_phase_table[] = {
                0x0, 0x1, 0x3, 0x2, 0x6, 0x7, 0x5, 0x4,
                0xc, 0xd, 0xf, 0xe, 0xa, 0xb, 0x9, 0x8
        };
        unsigned long flags;
        u32 config;
        struct mmc_host *mmc = host->mmc;

        spin_lock_irqsave(&host->lock, flags);

        config = readl_relaxed(host->ioaddr + CORE_DLL_CONFIG);
        config &= ~(CORE_CDR_EN | CORE_CK_OUT_EN);
        config |= (CORE_CDR_EXT_EN | CORE_DLL_EN);
        writel_relaxed(config, host->ioaddr + CORE_DLL_CONFIG);

        /* Wait until CK_OUT_EN bit of DLL_CONFIG register becomes '0' */
        rc = msm_dll_poll_ck_out_en(host, 0);
        if (rc)
                goto err_out;

        /*
         * Write the selected DLL clock output phase (0 ... 15)
         * to CDR_SELEXT bit field of DLL_CONFIG register.
         */
        config = readl_relaxed(host->ioaddr + CORE_DLL_CONFIG);
        config &= ~CDR_SELEXT_MASK;
        config |= grey_coded_phase_table[phase] << CDR_SELEXT_SHIFT;
        writel_relaxed(config, host->ioaddr + CORE_DLL_CONFIG);

        /* Set CK_OUT_EN bit of DLL_CONFIG register to 1. */
        writel_relaxed((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
                        | CORE_CK_OUT_EN), host->ioaddr + CORE_DLL_CONFIG);

        /* Wait until CK_OUT_EN bit of DLL_CONFIG register becomes '1' */
        rc = msm_dll_poll_ck_out_en(host, 1);
        if (rc)
                goto err_out;

        config = readl_relaxed(host->ioaddr + CORE_DLL_CONFIG);
        config |= CORE_CDR_EN;
        config &= ~CORE_CDR_EXT_EN;
        writel_relaxed(config, host->ioaddr + CORE_DLL_CONFIG);
        goto out;

err_out:
        dev_err(mmc_dev(mmc), "%s: Failed to set DLL phase: %d\n",
               mmc_hostname(mmc), phase);
out:
        spin_unlock_irqrestore(&host->lock, flags);
        return rc;
}

/*
 * Find out the greatest range of consecuitive selected
 * DLL clock output phases that can be used as sampling
 * setting for SD3.0 UHS-I card read operation (in SDR104
 * timing mode) or for eMMC4.5 card read operation (in HS200
 * timing mode).
 * Select the 3/4 of the range and configure the DLL with the
 * selected DLL clock output phase.
 */

static int msm_find_most_appropriate_phase(struct sdhci_host *host,
                                           u8 *phase_table, u8 total_phases)
{
        int ret;
        u8 ranges[MAX_PHASES][MAX_PHASES] = { {0}, {0} };
        u8 phases_per_row[MAX_PHASES] = { 0 };
        int row_index = 0, col_index = 0, selected_row_index = 0, curr_max = 0;
        int i, cnt, phase_0_raw_index = 0, phase_15_raw_index = 0;
        bool phase_0_found = false, phase_15_found = false;
        struct mmc_host *mmc = host->mmc;

        if (!total_phases || (total_phases > MAX_PHASES)) {
                dev_err(mmc_dev(mmc), "%s: Invalid argument: total_phases=%d\n",
                       mmc_hostname(mmc), total_phases);
                return -EINVAL;
        }

        for (cnt = 0; cnt < total_phases; cnt++) {
                ranges[row_index][col_index] = phase_table[cnt];
                phases_per_row[row_index] += 1;
                col_index++;

                if ((cnt + 1) == total_phases) {
                        continue;
                /* check if next phase in phase_table is consecutive or not */
                } else if ((phase_table[cnt] + 1) != phase_table[cnt + 1]) {
                        row_index++;
                        col_index = 0;
                }
        }

        if (row_index >= MAX_PHASES)
                return -EINVAL;

        /* Check if phase-0 is present in first valid window? */
        if (!ranges[0][0]) {
                phase_0_found = true;
                phase_0_raw_index = 0;
                /* Check if cycle exist between 2 valid windows */
                for (cnt = 1; cnt <= row_index; cnt++) {
                        if (phases_per_row[cnt]) {
                                for (i = 0; i < phases_per_row[cnt]; i++) {
                                        if (ranges[cnt][i] == 15) {
                                                phase_15_found = true;
                                                phase_15_raw_index = cnt;
                                                break;
                                        }
                                }
                        }
                }
        }

        /* If 2 valid windows form cycle then merge them as single window */
        if (phase_0_found && phase_15_found) {
                /* number of phases in raw where phase 0 is present */
                u8 phases_0 = phases_per_row[phase_0_raw_index];
                /* number of phases in raw where phase 15 is present */
                u8 phases_15 = phases_per_row[phase_15_raw_index];

                if (phases_0 + phases_15 >= MAX_PHASES)
                        /*
                         * If there are more than 1 phase windows then total
                         * number of phases in both the windows should not be
                         * more than or equal to MAX_PHASES.
                         */
                        return -EINVAL;

                /* Merge 2 cyclic windows */
                i = phases_15;
                for (cnt = 0; cnt < phases_0; cnt++) {
                        ranges[phase_15_raw_index][i] =
                            ranges[phase_0_raw_index][cnt];
                        if (++i >= MAX_PHASES)
                                break;
                }

                phases_per_row[phase_0_raw_index] = 0;
                phases_per_row[phase_15_raw_index] = phases_15 + phases_0;
        }

        for (cnt = 0; cnt <= row_index; cnt++) {
                if (phases_per_row[cnt] > curr_max) {
                        curr_max = phases_per_row[cnt];
                        selected_row_index = cnt;
                }
        }

        i = (curr_max * 3) / 4;
        if (i)
                i--;

        ret = ranges[selected_row_index][i];

        if (ret >= MAX_PHASES) {
                ret = -EINVAL;
                dev_err(mmc_dev(mmc), "%s: Invalid phase selected=%d\n",
                       mmc_hostname(mmc), ret);
        }

        return ret;
}

static inline void msm_cm_dll_set_freq(struct sdhci_host *host)
{
        u32 mclk_freq = 0, config;

        /* Program the MCLK value to MCLK_FREQ bit field */
        if (host->clock <= 112000000)
                mclk_freq = 0;
        else if (host->clock <= 125000000)
                mclk_freq = 1;
        else if (host->clock <= 137000000)
                mclk_freq = 2;
        else if (host->clock <= 150000000)
                mclk_freq = 3;
        else if (host->clock <= 162000000)
                mclk_freq = 4;
        else if (host->clock <= 175000000)
                mclk_freq = 5;
        else if (host->clock <= 187000000)
                mclk_freq = 6;
        else if (host->clock <= 200000000)
                mclk_freq = 7;

        config = readl_relaxed(host->ioaddr + CORE_DLL_CONFIG);
        config &= ~CMUX_SHIFT_PHASE_MASK;
        config |= mclk_freq << CMUX_SHIFT_PHASE_SHIFT;
        writel_relaxed(config, host->ioaddr + CORE_DLL_CONFIG);
}

/* Initialize the DLL (Programmable Delay Line) */
static int msm_init_cm_dll(struct sdhci_host *host)
{
        struct mmc_host *mmc = host->mmc;
        int wait_cnt = 50;
        unsigned long flags;

        spin_lock_irqsave(&host->lock, flags);

        /*
         * Make sure that clock is always enabled when DLL
         * tuning is in progress. Keeping PWRSAVE ON may
         * turn off the clock.
         */
        writel_relaxed((readl_relaxed(host->ioaddr + CORE_VENDOR_SPEC)
                        & ~CORE_CLK_PWRSAVE), host->ioaddr + CORE_VENDOR_SPEC);

        /* Write 1 to DLL_RST bit of DLL_CONFIG register */
        writel_relaxed((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
                        | CORE_DLL_RST), host->ioaddr + CORE_DLL_CONFIG);

        /* Write 1 to DLL_PDN bit of DLL_CONFIG register */
        writel_relaxed((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
                        | CORE_DLL_PDN), host->ioaddr + CORE_DLL_CONFIG);
        msm_cm_dll_set_freq(host);

        /* Write 0 to DLL_RST bit of DLL_CONFIG register */
        writel_relaxed((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
                        & ~CORE_DLL_RST), host->ioaddr + CORE_DLL_CONFIG);

        /* Write 0 to DLL_PDN bit of DLL_CONFIG register */
        writel_relaxed((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
                        & ~CORE_DLL_PDN), host->ioaddr + CORE_DLL_CONFIG);

        /* Set DLL_EN bit to 1. */
        writel_relaxed((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
                        | CORE_DLL_EN), host->ioaddr + CORE_DLL_CONFIG);

        /* Set CK_OUT_EN bit to 1. */
        writel_relaxed((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
                        | CORE_CK_OUT_EN), host->ioaddr + CORE_DLL_CONFIG);

        /* Wait until DLL_LOCK bit of DLL_STATUS register becomes '1' */
        while (!(readl_relaxed(host->ioaddr + CORE_DLL_STATUS) &
                 CORE_DLL_LOCK)) {
                /* max. wait for 50us sec for LOCK bit to be set */
                if (--wait_cnt == 0) {
                        dev_err(mmc_dev(mmc), "%s: DLL failed to LOCK\n",
                               mmc_hostname(mmc));
                        spin_unlock_irqrestore(&host->lock, flags);
                        return -ETIMEDOUT;
                }
                udelay(1);
        }

        spin_unlock_irqrestore(&host->lock, flags);
        return 0;
}

static int sdhci_msm_execute_tuning(struct sdhci_host *host, u32 opcode)
{
        int tuning_seq_cnt = 3;
        u8 phase, *data_buf, tuned_phases[16], tuned_phase_cnt = 0;
        const u32 *tuning_block_pattern = tuning_block_64;
        int size = sizeof(tuning_block_64);     /* Pattern size in bytes */
        int rc;
        struct mmc_host *mmc = host->mmc;
        struct mmc_ios ios = host->mmc->ios;

        /*
         * Tuning is required for SDR104, HS200 and HS400 cards and
         * if clock frequency is greater than 100MHz in these modes.
         */
        if (host->clock <= 100 * 1000 * 1000 ||
            !((ios.timing == MMC_TIMING_MMC_HS200) ||
              (ios.timing == MMC_TIMING_UHS_SDR104)))
                return 0;

        if ((opcode == MMC_SEND_TUNING_BLOCK_HS200) &&
            (mmc->ios.bus_width == MMC_BUS_WIDTH_8)) {
                tuning_block_pattern = tuning_block_128;
                size = sizeof(tuning_block_128);
        }

        data_buf = kmalloc(size, GFP_KERNEL);
        if (!data_buf)
                return -ENOMEM;

retry:
        /* First of all reset the tuning block */
        rc = msm_init_cm_dll(host);
        if (rc)
                goto out;

        phase = 0;
        do {
                struct mmc_command cmd = { 0 };
                struct mmc_data data = { 0 };
                struct mmc_request mrq = {
                        .cmd = &cmd,
                        .data = &data
                };
                struct scatterlist sg;

                /* Set the phase in delay line hw block */
                rc = msm_config_cm_dll_phase(host, phase);
                if (rc)
                        goto out;

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

                data.blksz = size;
                data.blocks = 1;
                data.flags = MMC_DATA_READ;
                data.timeout_ns = NSEC_PER_SEC; /* 1 second */

                data.sg = &sg;
                data.sg_len = 1;
                sg_init_one(&sg, data_buf, size);
                memset(data_buf, 0, size);
                mmc_wait_for_req(mmc, &mrq);

                if (!cmd.error && !data.error &&
                    !memcmp(data_buf, tuning_block_pattern, size)) {
                        /* Tuning is successful at this tuning point */
                        tuned_phases[tuned_phase_cnt++] = phase;
                        dev_dbg(mmc_dev(mmc), "%s: Found good phase = %d\n",
                                 mmc_hostname(mmc), phase);
                }
        } while (++phase < ARRAY_SIZE(tuned_phases));

        if (tuned_phase_cnt) {
                rc = msm_find_most_appropriate_phase(host, tuned_phases,
                                                     tuned_phase_cnt);
                if (rc < 0)
                        goto out;
                else
                        phase = rc;

                /*
                 * Finally set the selected phase in delay
                 * line hw block.
                 */
                rc = msm_config_cm_dll_phase(host, phase);
                if (rc)
                        goto out;
                dev_dbg(mmc_dev(mmc), "%s: Setting the tuning phase to %d\n",
                         mmc_hostname(mmc), phase);
        } else {
                if (--tuning_seq_cnt)
                        goto retry;
                /* Tuning failed */
                dev_dbg(mmc_dev(mmc), "%s: No tuning point found\n",
                       mmc_hostname(mmc));
                rc = -EIO;
        }

out:
        kfree(data_buf);
        return rc;
}

static const struct of_device_id sdhci_msm_dt_match[] = {
        { .compatible = "qcom,sdhci-msm-v4" },
        {},
};

MODULE_DEVICE_TABLE(of, sdhci_msm_dt_match);

static struct sdhci_ops sdhci_msm_ops = {
        .platform_execute_tuning = sdhci_msm_execute_tuning,
        .reset = sdhci_reset,
        .set_clock = sdhci_set_clock,
        .set_bus_width = sdhci_set_bus_width,
        .set_uhs_signaling = sdhci_set_uhs_signaling,
};

static int sdhci_msm_probe(struct platform_device *pdev)
{
        struct sdhci_host *host;
        struct sdhci_pltfm_host *pltfm_host;
        struct sdhci_msm_host *msm_host;
        struct resource *core_memres;
        int ret;
        u16 host_version;

        msm_host = devm_kzalloc(&pdev->dev, sizeof(*msm_host), GFP_KERNEL);
        if (!msm_host)
                return -ENOMEM;

        msm_host->sdhci_msm_pdata.ops = &sdhci_msm_ops;
        host = sdhci_pltfm_init(pdev, &msm_host->sdhci_msm_pdata, 0);
        if (IS_ERR(host))
                return PTR_ERR(host);

        pltfm_host = sdhci_priv(host);
        pltfm_host->priv = msm_host;
        msm_host->mmc = host->mmc;
        msm_host->pdev = pdev;

        ret = mmc_of_parse(host->mmc);
        if (ret)
                goto pltfm_free;

        sdhci_get_of_property(pdev);

        /* Setup SDCC bus voter clock. */
        msm_host->bus_clk = devm_clk_get(&pdev->dev, "bus");
        if (!IS_ERR(msm_host->bus_clk)) {
                /* Vote for max. clk rate for max. performance */
                ret = clk_set_rate(msm_host->bus_clk, INT_MAX);
                if (ret)
                        goto pltfm_free;
                ret = clk_prepare_enable(msm_host->bus_clk);
                if (ret)
                        goto pltfm_free;
        }

        /* Setup main peripheral bus clock */
        msm_host->pclk = devm_clk_get(&pdev->dev, "iface");
        if (IS_ERR(msm_host->pclk)) {
                ret = PTR_ERR(msm_host->pclk);
                dev_err(&pdev->dev, "Perpheral clk setup failed (%d)\n", ret);
                goto bus_clk_disable;
        }

        ret = clk_prepare_enable(msm_host->pclk);
        if (ret)
                goto bus_clk_disable;

        /* Setup SDC MMC clock */
        msm_host->clk = devm_clk_get(&pdev->dev, "core");
        if (IS_ERR(msm_host->clk)) {
                ret = PTR_ERR(msm_host->clk);
                dev_err(&pdev->dev, "SDC MMC clk setup failed (%d)\n", ret);
                goto pclk_disable;
        }

        ret = clk_prepare_enable(msm_host->clk);
        if (ret)
                goto pclk_disable;

        core_memres = platform_get_resource(pdev, IORESOURCE_MEM, 1);
        msm_host->core_mem = devm_ioremap_resource(&pdev->dev, core_memres);

        if (IS_ERR(msm_host->core_mem)) {
                dev_err(&pdev->dev, "Failed to remap registers\n");
                ret = PTR_ERR(msm_host->core_mem);
                goto clk_disable;
        }

        /* Reset the core and Enable SDHC mode */
        writel_relaxed(readl_relaxed(msm_host->core_mem + CORE_POWER) |
                       CORE_SW_RST, msm_host->core_mem + CORE_POWER);

        /* SW reset can take upto 10HCLK + 15MCLK cycles. (min 40us) */
        usleep_range(1000, 5000);
        if (readl(msm_host->core_mem + CORE_POWER) & CORE_SW_RST) {
                dev_err(&pdev->dev, "Stuck in reset\n");
                ret = -ETIMEDOUT;
                goto clk_disable;
        }

        /* Set HC_MODE_EN bit in HC_MODE register */
        writel_relaxed(HC_MODE_EN, (msm_host->core_mem + CORE_HC_MODE));

        host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;
        host->quirks |= SDHCI_QUIRK_SINGLE_POWER_WRITE;

        host_version = readw_relaxed((host->ioaddr + SDHCI_HOST_VERSION));
        dev_dbg(&pdev->dev, "Host Version: 0x%x Vendor Version 0x%x\n",
                host_version, ((host_version & SDHCI_VENDOR_VER_MASK) >>
                               SDHCI_VENDOR_VER_SHIFT));

        ret = sdhci_add_host(host);
        if (ret)
                goto clk_disable;

        return 0;

clk_disable:
        clk_disable_unprepare(msm_host->clk);
pclk_disable:
        clk_disable_unprepare(msm_host->pclk);
bus_clk_disable:
        if (!IS_ERR(msm_host->bus_clk))
                clk_disable_unprepare(msm_host->bus_clk);
pltfm_free:
        sdhci_pltfm_free(pdev);
        return ret;
}

static int sdhci_msm_remove(struct platform_device *pdev)
{
        struct sdhci_host *host = platform_get_drvdata(pdev);
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
        struct sdhci_msm_host *msm_host = pltfm_host->priv;
        int dead = (readl_relaxed(host->ioaddr + SDHCI_INT_STATUS) ==
                    0xffffffff);

        sdhci_remove_host(host, dead);
        sdhci_pltfm_free(pdev);
        clk_disable_unprepare(msm_host->clk);
        clk_disable_unprepare(msm_host->pclk);
        if (!IS_ERR(msm_host->bus_clk))
                clk_disable_unprepare(msm_host->bus_clk);
        return 0;
}

static struct platform_driver sdhci_msm_driver = {
        .probe = sdhci_msm_probe,
        .remove = sdhci_msm_remove,
        .driver = {
                   .name = "sdhci_msm",
                   .owner = THIS_MODULE,
                   .of_match_table = sdhci_msm_dt_match,
        },
};

module_platform_driver(sdhci_msm_driver);

MODULE_DESCRIPTION("Qualcomm Secure Digital Host Controller Interface driver");
MODULE_LICENSE("GPL v2");