/*
 * Driver for the MMC / SD / SDIO IP found in:
 *
 * TC6393XB, TC6391XB, TC6387XB, T7L66XB, ASIC3, SH-Mobile SoCs
 *
 * Copyright (C) 2015-17 Renesas Electronics Corporation
 * Copyright (C) 2016-17 Sang Engineering, Wolfram Sang
 * Copyright (C) 2017 Horms Solutions, Simon Horman
 * Copyright (C) 2011 Guennadi Liakhovetski
 * Copyright (C) 2007 Ian Molton
 * Copyright (C) 2004 Ian Molton
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This driver draws mainly on scattered spec sheets, Reverse engineering
 * of the toshiba e800  SD driver and some parts of the 2.4 ASIC3 driver (4 bit
 * support). (Further 4 bit support from a later datasheet).
 *
 * TODO:
 *   Investigate using a workqueue for PIO transfers
 *   Eliminate FIXMEs
 *   Better Power management
 *   Handle MMC errors better
 *   double buffer support
 *
 */

#include <linux/delay.h>
#include <linux/device.h>
#include <linux/highmem.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/mfd/tmio.h>
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/mmc/mmc.h>
#include <linux/mmc/slot-gpio.h>
#include <linux/module.h>
#include <linux/pagemap.h>
#include <linux/platform_device.h>
#include <linux/pm_qos.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>
#include <linux/mmc/sdio.h>
#include <linux/scatterlist.h>
#include <linux/spinlock.h>
#include <linux/swiotlb.h>
#include <linux/workqueue.h>

#include "tmio_mmc.h"

static inline void tmio_mmc_start_dma(struct tmio_mmc_host *host,
                                      struct mmc_data *data)
{
        if (host->dma_ops)
                host->dma_ops->start(host, data);
}

static inline void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
{
        if (host->dma_ops)
                host->dma_ops->enable(host, enable);
}

static inline void tmio_mmc_request_dma(struct tmio_mmc_host *host,
                                        struct tmio_mmc_data *pdata)
{
        if (host->dma_ops) {
                host->dma_ops->request(host, pdata);
        } else {
                host->chan_tx = NULL;
                host->chan_rx = NULL;
        }
}

static inline void tmio_mmc_release_dma(struct tmio_mmc_host *host)
{
        if (host->dma_ops)
                host->dma_ops->release(host);
}

static inline void tmio_mmc_abort_dma(struct tmio_mmc_host *host)
{
        if (host->dma_ops)
                host->dma_ops->abort(host);
}

static inline void tmio_mmc_dataend_dma(struct tmio_mmc_host *host)
{
        if (host->dma_ops)
                host->dma_ops->dataend(host);
}

void tmio_mmc_enable_mmc_irqs(struct tmio_mmc_host *host, u32 i)
{
        host->sdcard_irq_mask &= ~(i & TMIO_MASK_IRQ);
        sd_ctrl_write32_as_16_and_16(host, CTL_IRQ_MASK, host->sdcard_irq_mask);
}
EXPORT_SYMBOL_GPL(tmio_mmc_enable_mmc_irqs);

void tmio_mmc_disable_mmc_irqs(struct tmio_mmc_host *host, u32 i)
{
        host->sdcard_irq_mask |= (i & TMIO_MASK_IRQ);
        sd_ctrl_write32_as_16_and_16(host, CTL_IRQ_MASK, host->sdcard_irq_mask);
}
EXPORT_SYMBOL_GPL(tmio_mmc_disable_mmc_irqs);

static void tmio_mmc_ack_mmc_irqs(struct tmio_mmc_host *host, u32 i)
{
        sd_ctrl_write32_as_16_and_16(host, CTL_STATUS, ~i);
}

static void tmio_mmc_init_sg(struct tmio_mmc_host *host, struct mmc_data *data)
{
        host->sg_len = data->sg_len;
        host->sg_ptr = data->sg;
        host->sg_orig = data->sg;
        host->sg_off = 0;
}

static int tmio_mmc_next_sg(struct tmio_mmc_host *host)
{
        host->sg_ptr = sg_next(host->sg_ptr);
        host->sg_off = 0;
        return --host->sg_len;
}

#define CMDREQ_TIMEOUT  5000

static void tmio_mmc_enable_sdio_irq(struct mmc_host *mmc, int enable)
{
        struct tmio_mmc_host *host = mmc_priv(mmc);

        if (enable && !host->sdio_irq_enabled) {
                u16 sdio_status;

                /* Keep device active while SDIO irq is enabled */
                pm_runtime_get_sync(mmc_dev(mmc));

                host->sdio_irq_enabled = true;
                host->sdio_irq_mask = TMIO_SDIO_MASK_ALL & ~TMIO_SDIO_STAT_IOIRQ;

                /* Clear obsolete interrupts before enabling */
                sdio_status = sd_ctrl_read16(host, CTL_SDIO_STATUS) & ~TMIO_SDIO_MASK_ALL;
                if (host->pdata->flags & TMIO_MMC_SDIO_STATUS_SETBITS)
                        sdio_status |= TMIO_SDIO_SETBITS_MASK;
                sd_ctrl_write16(host, CTL_SDIO_STATUS, sdio_status);

                sd_ctrl_write16(host, CTL_SDIO_IRQ_MASK, host->sdio_irq_mask);
        } else if (!enable && host->sdio_irq_enabled) {
                host->sdio_irq_mask = TMIO_SDIO_MASK_ALL;
                sd_ctrl_write16(host, CTL_SDIO_IRQ_MASK, host->sdio_irq_mask);

                host->sdio_irq_enabled = false;
                pm_runtime_mark_last_busy(mmc_dev(mmc));
                pm_runtime_put_autosuspend(mmc_dev(mmc));
        }
}

static void tmio_mmc_clk_start(struct tmio_mmc_host *host)
{
        sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, CLK_CTL_SCLKEN |
                sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));

        /* HW engineers overrode docs: no sleep needed on R-Car2+ */
        if (!(host->pdata->flags & TMIO_MMC_MIN_RCAR2))
                usleep_range(10000, 11000);

        if (host->pdata->flags & TMIO_MMC_HAVE_HIGH_REG) {
                sd_ctrl_write16(host, CTL_CLK_AND_WAIT_CTL, 0x0100);
                usleep_range(10000, 11000);
        }
}

static void tmio_mmc_clk_stop(struct tmio_mmc_host *host)
{
        if (host->pdata->flags & TMIO_MMC_HAVE_HIGH_REG) {
                sd_ctrl_write16(host, CTL_CLK_AND_WAIT_CTL, 0x0000);
                usleep_range(10000, 11000);
        }

        sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~CLK_CTL_SCLKEN &
                sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));

        /* HW engineers overrode docs: no sleep needed on R-Car2+ */
        if (!(host->pdata->flags & TMIO_MMC_MIN_RCAR2))
                usleep_range(10000, 11000);
}

static void tmio_mmc_set_clock(struct tmio_mmc_host *host,
                               unsigned int new_clock)
{
        u32 clk = 0, clock;

        if (new_clock == 0) {
                tmio_mmc_clk_stop(host);
                return;
        }

        if (host->clk_update)
                clock = host->clk_update(host, new_clock) / 512;
        else
                clock = host->mmc->f_min;

        for (clk = 0x80000080; new_clock >= (clock << 1); clk >>= 1)
                clock <<= 1;

        /* 1/1 clock is option */
        if ((host->pdata->flags & TMIO_MMC_CLK_ACTUAL) && ((clk >> 22) & 0x1))
                clk |= 0xff;

        if (host->set_clk_div)
                host->set_clk_div(host->pdev, (clk >> 22) & 1);

        sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~CLK_CTL_SCLKEN &
                        sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
        sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, clk & CLK_CTL_DIV_MASK);
        if (!(host->pdata->flags & TMIO_MMC_MIN_RCAR2))
                usleep_range(10000, 11000);

        tmio_mmc_clk_start(host);
}

static void tmio_mmc_reset(struct tmio_mmc_host *host)
{
        /* FIXME - should we set stop clock reg here */
        sd_ctrl_write16(host, CTL_RESET_SD, 0x0000);
        if (host->pdata->flags & TMIO_MMC_HAVE_HIGH_REG)
                sd_ctrl_write16(host, CTL_RESET_SDIO, 0x0000);
        usleep_range(10000, 11000);
        sd_ctrl_write16(host, CTL_RESET_SD, 0x0001);
        if (host->pdata->flags & TMIO_MMC_HAVE_HIGH_REG)
                sd_ctrl_write16(host, CTL_RESET_SDIO, 0x0001);
        usleep_range(10000, 11000);

        if (host->pdata->flags & TMIO_MMC_SDIO_IRQ) {
                sd_ctrl_write16(host, CTL_SDIO_IRQ_MASK, host->sdio_irq_mask);
                sd_ctrl_write16(host, CTL_TRANSACTION_CTL, 0x0001);
        }

}

static void tmio_mmc_reset_work(struct work_struct *work)
{
        struct tmio_mmc_host *host = container_of(work, struct tmio_mmc_host,
                                                  delayed_reset_work.work);
        struct mmc_request *mrq;
        unsigned long flags;

        spin_lock_irqsave(&host->lock, flags);
        mrq = host->mrq;

        /*
         * is request already finished? Since we use a non-blocking
         * cancel_delayed_work(), it can happen, that a .set_ios() call preempts
         * us, so, have to check for IS_ERR(host->mrq)
         */
        if (IS_ERR_OR_NULL(mrq) ||
            time_is_after_jiffies(host->last_req_ts +
                                  msecs_to_jiffies(CMDREQ_TIMEOUT))) {
                spin_unlock_irqrestore(&host->lock, flags);
                return;
        }

        dev_warn(&host->pdev->dev,
                 "timeout waiting for hardware interrupt (CMD%u)\n",
                 mrq->cmd->opcode);

        if (host->data)
                host->data->error = -ETIMEDOUT;
        else if (host->cmd)
                host->cmd->error = -ETIMEDOUT;
        else
                mrq->cmd->error = -ETIMEDOUT;

        host->cmd = NULL;
        host->data = NULL;
        host->force_pio = false;

        spin_unlock_irqrestore(&host->lock, flags);

        tmio_mmc_reset(host);

        /* Ready for new calls */
        host->mrq = NULL;

        tmio_mmc_abort_dma(host);
        mmc_request_done(host->mmc, mrq);
}

/* These are the bitmasks the tmio chip requires to implement the MMC response
 * types. Note that R1 and R6 are the same in this scheme. */
#define APP_CMD        0x0040
#define RESP_NONE      0x0300
#define RESP_R1        0x0400
#define RESP_R1B       0x0500
#define RESP_R2        0x0600
#define RESP_R3        0x0700
#define DATA_PRESENT   0x0800
#define TRANSFER_READ  0x1000
#define TRANSFER_MULTI 0x2000
#define SECURITY_CMD   0x4000
#define NO_CMD12_ISSUE 0x4000 /* TMIO_MMC_HAVE_CMD12_CTRL */

static int tmio_mmc_start_command(struct tmio_mmc_host *host,
                                  struct mmc_command *cmd)
{
        struct mmc_data *data = host->data;
        int c = cmd->opcode;
        u32 irq_mask = TMIO_MASK_CMD;

        switch (mmc_resp_type(cmd)) {
        case MMC_RSP_NONE: c |= RESP_NONE; break;
        case MMC_RSP_R1:
        case MMC_RSP_R1_NO_CRC:
                           c |= RESP_R1;   break;
        case MMC_RSP_R1B:  c |= RESP_R1B;  break;
        case MMC_RSP_R2:   c |= RESP_R2;   break;
        case MMC_RSP_R3:   c |= RESP_R3;   break;
        default:
                pr_debug("Unknown response type %d\n", mmc_resp_type(cmd));
                return -EINVAL;
        }

        host->cmd = cmd;

/* FIXME - this seems to be ok commented out but the spec suggest this bit
 *         should be set when issuing app commands.
 *      if(cmd->flags & MMC_FLAG_ACMD)
 *              c |= APP_CMD;
 */
        if (data) {
                c |= DATA_PRESENT;
                if (data->blocks > 1) {
                        sd_ctrl_write16(host, CTL_STOP_INTERNAL_ACTION, TMIO_STOP_SEC);
                        c |= TRANSFER_MULTI;

                        /*
                         * Disable auto CMD12 at IO_RW_EXTENDED and
                         * SET_BLOCK_COUNT when doing multiple block transfer
                         */
                        if ((host->pdata->flags & TMIO_MMC_HAVE_CMD12_CTRL) &&
                            (cmd->opcode == SD_IO_RW_EXTENDED || host->mrq->sbc))
                                c |= NO_CMD12_ISSUE;
                }
                if (data->flags & MMC_DATA_READ)
                        c |= TRANSFER_READ;
        }

        if (!host->native_hotplug)
                irq_mask &= ~(TMIO_STAT_CARD_REMOVE | TMIO_STAT_CARD_INSERT);
        tmio_mmc_enable_mmc_irqs(host, irq_mask);

        /* Fire off the command */
        sd_ctrl_write32_as_16_and_16(host, CTL_ARG_REG, cmd->arg);
        sd_ctrl_write16(host, CTL_SD_CMD, c);

        return 0;
}

static void tmio_mmc_transfer_data(struct tmio_mmc_host *host,
                                   unsigned short *buf,
                                   unsigned int count)
{
        int is_read = host->data->flags & MMC_DATA_READ;
        u8  *buf8;

        /*
         * Transfer the data
         */
        if (host->pdata->flags & TMIO_MMC_32BIT_DATA_PORT) {
                u32 data = 0;
                u32 *buf32 = (u32 *)buf;

                if (is_read)
                        sd_ctrl_read32_rep(host, CTL_SD_DATA_PORT, buf32,
                                           count >> 2);
                else
                        sd_ctrl_write32_rep(host, CTL_SD_DATA_PORT, buf32,
                                            count >> 2);

                /* if count was multiple of 4 */
                if (!(count & 0x3))
                        return;

                buf32 += count >> 2;
                count %= 4;

                if (is_read) {
                        sd_ctrl_read32_rep(host, CTL_SD_DATA_PORT, &data, 1);
                        memcpy(buf32, &data, count);
                } else {
                        memcpy(&data, buf32, count);
                        sd_ctrl_write32_rep(host, CTL_SD_DATA_PORT, &data, 1);
                }

                return;
        }

        if (is_read)
                sd_ctrl_read16_rep(host, CTL_SD_DATA_PORT, buf, count >> 1);
        else
                sd_ctrl_write16_rep(host, CTL_SD_DATA_PORT, buf, count >> 1);

        /* if count was even number */
        if (!(count & 0x1))
                return;

        /* if count was odd number */
        buf8 = (u8 *)(buf + (count >> 1));

        /*
         * FIXME
         *
         * driver and this function are assuming that
         * it is used as little endian
         */
        if (is_read)
                *buf8 = sd_ctrl_read16(host, CTL_SD_DATA_PORT) & 0xff;
        else
                sd_ctrl_write16(host, CTL_SD_DATA_PORT, *buf8);
}

/*
 * This chip always returns (at least?) as much data as you ask for.
 * I'm unsure what happens if you ask for less than a block. This should be
 * looked into to ensure that a funny length read doesn't hose the controller.
 */
static void tmio_mmc_pio_irq(struct tmio_mmc_host *host)
{
        struct mmc_data *data = host->data;
        void *sg_virt;
        unsigned short *buf;
        unsigned int count;
        unsigned long flags;

        if ((host->chan_tx || host->chan_rx) && !host->force_pio) {
                pr_err("PIO IRQ in DMA mode!\n");
                return;
        } else if (!data) {
                pr_debug("Spurious PIO IRQ\n");
                return;
        }

        sg_virt = tmio_mmc_kmap_atomic(host->sg_ptr, &flags);
        buf = (unsigned short *)(sg_virt + host->sg_off);

        count = host->sg_ptr->length - host->sg_off;
        if (count > data->blksz)
                count = data->blksz;

        pr_debug("count: %08x offset: %08x flags %08x\n",
                 count, host->sg_off, data->flags);

        /* Transfer the data */
        tmio_mmc_transfer_data(host, buf, count);

        host->sg_off += count;

        tmio_mmc_kunmap_atomic(host->sg_ptr, &flags, sg_virt);

        if (host->sg_off == host->sg_ptr->length)
                tmio_mmc_next_sg(host);
}

static void tmio_mmc_check_bounce_buffer(struct tmio_mmc_host *host)
{
        if (host->sg_ptr == &host->bounce_sg) {
                unsigned long flags;
                void *sg_vaddr = tmio_mmc_kmap_atomic(host->sg_orig, &flags);

                memcpy(sg_vaddr, host->bounce_buf, host->bounce_sg.length);
                tmio_mmc_kunmap_atomic(host->sg_orig, &flags, sg_vaddr);
        }
}

/* needs to be called with host->lock held */
void tmio_mmc_do_data_irq(struct tmio_mmc_host *host)
{
        struct mmc_data *data = host->data;
        struct mmc_command *stop;

        host->data = NULL;

        if (!data) {
                dev_warn(&host->pdev->dev, "Spurious data end IRQ\n");
                return;
        }
        stop = data->stop;

        /* FIXME - return correct transfer count on errors */
        if (!data->error)
                data->bytes_xfered = data->blocks * data->blksz;
        else
                data->bytes_xfered = 0;

        pr_debug("Completed data request\n");

        /*
         * FIXME: other drivers allow an optional stop command of any given type
         *        which we dont do, as the chip can auto generate them.
         *        Perhaps we can be smarter about when to use auto CMD12 and
         *        only issue the auto request when we know this is the desired
         *        stop command, allowing fallback to the stop command the
         *        upper layers expect. For now, we do what works.
         */

        if (data->flags & MMC_DATA_READ) {
                if (host->chan_rx && !host->force_pio)
                        tmio_mmc_check_bounce_buffer(host);
                dev_dbg(&host->pdev->dev, "Complete Rx request %p\n",
                        host->mrq);
        } else {
                dev_dbg(&host->pdev->dev, "Complete Tx request %p\n",
                        host->mrq);
        }

        if (stop && !host->mrq->sbc) {
                if (stop->opcode != MMC_STOP_TRANSMISSION || stop->arg)
                        dev_err(&host->pdev->dev, "unsupported stop: CMD%u,0x%x. We did CMD12,0\n",
                                stop->opcode, stop->arg);

                /* fill in response from auto CMD12 */
                stop->resp[0] = sd_ctrl_read16_and_16_as_32(host, CTL_RESPONSE);

                sd_ctrl_write16(host, CTL_STOP_INTERNAL_ACTION, 0);
        }

        schedule_work(&host->done);
}
EXPORT_SYMBOL_GPL(tmio_mmc_do_data_irq);

static void tmio_mmc_data_irq(struct tmio_mmc_host *host, unsigned int stat)
{
        struct mmc_data *data;

        spin_lock(&host->lock);
        data = host->data;

        if (!data)
                goto out;

        if (stat & TMIO_STAT_CRCFAIL || stat & TMIO_STAT_STOPBIT_ERR ||
            stat & TMIO_STAT_TXUNDERRUN)
                data->error = -EILSEQ;
        if (host->chan_tx && (data->flags & MMC_DATA_WRITE) && !host->force_pio) {
                u32 status = sd_ctrl_read16_and_16_as_32(host, CTL_STATUS);
                bool done = false;

                /*
                 * Has all data been written out yet? Testing on SuperH showed,
                 * that in most cases the first interrupt comes already with the
                 * BUSY status bit clear, but on some operations, like mount or
                 * in the beginning of a write / sync / umount, there is one
                 * DATAEND interrupt with the BUSY bit set, in this cases
                 * waiting for one more interrupt fixes the problem.
                 */
                if (host->pdata->flags & TMIO_MMC_HAS_IDLE_WAIT) {
                        if (status & TMIO_STAT_SCLKDIVEN)
                                done = true;
                } else {
                        if (!(status & TMIO_STAT_CMD_BUSY))
                                done = true;
                }

                if (done) {
                        tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_DATAEND);
                        tmio_mmc_dataend_dma(host);
                }
        } else if (host->chan_rx && (data->flags & MMC_DATA_READ) && !host->force_pio) {
                tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_DATAEND);
                tmio_mmc_dataend_dma(host);
        } else {
                tmio_mmc_do_data_irq(host);
                tmio_mmc_disable_mmc_irqs(host, TMIO_MASK_READOP | TMIO_MASK_WRITEOP);
        }
out:
        spin_unlock(&host->lock);
}

static void tmio_mmc_cmd_irq(struct tmio_mmc_host *host, unsigned int stat)
{
        struct mmc_command *cmd = host->cmd;
        int i, addr;

        spin_lock(&host->lock);

        if (!host->cmd) {
                pr_debug("Spurious CMD irq\n");
                goto out;
        }

        /* This controller is sicker than the PXA one. Not only do we need to
         * drop the top 8 bits of the first response word, we also need to
         * modify the order of the response for short response command types.
         */

        for (i = 3, addr = CTL_RESPONSE ; i >= 0 ; i--, addr += 4)
                cmd->resp[i] = sd_ctrl_read16_and_16_as_32(host, addr);

        if (cmd->flags &  MMC_RSP_136) {
                cmd->resp[0] = (cmd->resp[0] << 8) | (cmd->resp[1] >> 24);
                cmd->resp[1] = (cmd->resp[1] << 8) | (cmd->resp[2] >> 24);
                cmd->resp[2] = (cmd->resp[2] << 8) | (cmd->resp[3] >> 24);
                cmd->resp[3] <<= 8;
        } else if (cmd->flags & MMC_RSP_R3) {
                cmd->resp[0] = cmd->resp[3];
        }

        if (stat & TMIO_STAT_CMDTIMEOUT)
                cmd->error = -ETIMEDOUT;
        else if ((stat & TMIO_STAT_CRCFAIL && cmd->flags & MMC_RSP_CRC) ||
                 stat & TMIO_STAT_STOPBIT_ERR ||
                 stat & TMIO_STAT_CMD_IDX_ERR)
                cmd->error = -EILSEQ;

        /* If there is data to handle we enable data IRQs here, and
         * we will ultimatley finish the request in the data_end handler.
         * If theres no data or we encountered an error, finish now.
         */
        if (host->data && (!cmd->error || cmd->error == -EILSEQ)) {
                if (host->data->flags & MMC_DATA_READ) {
                        if (host->force_pio || !host->chan_rx)
                                tmio_mmc_enable_mmc_irqs(host, TMIO_MASK_READOP);
                        else
                                tasklet_schedule(&host->dma_issue);
                } else {
                        if (host->force_pio || !host->chan_tx)
                                tmio_mmc_enable_mmc_irqs(host, TMIO_MASK_WRITEOP);
                        else
                                tasklet_schedule(&host->dma_issue);
                }
        } else {
                schedule_work(&host->done);
        }

out:
        spin_unlock(&host->lock);
}

static bool __tmio_mmc_card_detect_irq(struct tmio_mmc_host *host,
                                       int ireg, int status)
{
        struct mmc_host *mmc = host->mmc;

        /* Card insert / remove attempts */
        if (ireg & (TMIO_STAT_CARD_INSERT | TMIO_STAT_CARD_REMOVE)) {
                tmio_mmc_ack_mmc_irqs(host, TMIO_STAT_CARD_INSERT |
                        TMIO_STAT_CARD_REMOVE);
                if ((((ireg & TMIO_STAT_CARD_REMOVE) && mmc->card) ||
                     ((ireg & TMIO_STAT_CARD_INSERT) && !mmc->card)) &&
                    !work_pending(&mmc->detect.work))
                        mmc_detect_change(host->mmc, msecs_to_jiffies(100));
                return true;
        }

        return false;
}

static bool __tmio_mmc_sdcard_irq(struct tmio_mmc_host *host, int ireg,
                                  int status)
{
        /* Command completion */
        if (ireg & (TMIO_STAT_CMDRESPEND | TMIO_STAT_CMDTIMEOUT)) {
                tmio_mmc_ack_mmc_irqs(host, TMIO_STAT_CMDRESPEND |
                                      TMIO_STAT_CMDTIMEOUT);
                tmio_mmc_cmd_irq(host, status);
                return true;
        }

        /* Data transfer */
        if (ireg & (TMIO_STAT_RXRDY | TMIO_STAT_TXRQ)) {
                tmio_mmc_ack_mmc_irqs(host, TMIO_STAT_RXRDY | TMIO_STAT_TXRQ);
                tmio_mmc_pio_irq(host);
                return true;
        }

        /* Data transfer completion */
        if (ireg & TMIO_STAT_DATAEND) {
                tmio_mmc_ack_mmc_irqs(host, TMIO_STAT_DATAEND);
                tmio_mmc_data_irq(host, status);
                return true;
        }

        return false;
}

static void __tmio_mmc_sdio_irq(struct tmio_mmc_host *host)
{
        struct mmc_host *mmc = host->mmc;
        struct tmio_mmc_data *pdata = host->pdata;
        unsigned int ireg, status;
        unsigned int sdio_status;

        if (!(pdata->flags & TMIO_MMC_SDIO_IRQ))
                return;

        status = sd_ctrl_read16(host, CTL_SDIO_STATUS);
        ireg = status & TMIO_SDIO_MASK_ALL & ~host->sdio_irq_mask;

        sdio_status = status & ~TMIO_SDIO_MASK_ALL;
        if (pdata->flags & TMIO_MMC_SDIO_STATUS_SETBITS)
                sdio_status |= TMIO_SDIO_SETBITS_MASK;

        sd_ctrl_write16(host, CTL_SDIO_STATUS, sdio_status);

        if (mmc->caps & MMC_CAP_SDIO_IRQ && ireg & TMIO_SDIO_STAT_IOIRQ)
                mmc_signal_sdio_irq(mmc);
}

irqreturn_t tmio_mmc_irq(int irq, void *devid)
{
        struct tmio_mmc_host *host = devid;
        unsigned int ireg, status;

        status = sd_ctrl_read16_and_16_as_32(host, CTL_STATUS);
        ireg = status & TMIO_MASK_IRQ & ~host->sdcard_irq_mask;

        /* Clear the status except the interrupt status */
        sd_ctrl_write32_as_16_and_16(host, CTL_STATUS, TMIO_MASK_IRQ);

        if (__tmio_mmc_card_detect_irq(host, ireg, status))
                return IRQ_HANDLED;
        if (__tmio_mmc_sdcard_irq(host, ireg, status))
                return IRQ_HANDLED;

        __tmio_mmc_sdio_irq(host);

        return IRQ_HANDLED;
}
EXPORT_SYMBOL_GPL(tmio_mmc_irq);

static int tmio_mmc_start_data(struct tmio_mmc_host *host,
                               struct mmc_data *data)
{
        struct tmio_mmc_data *pdata = host->pdata;

        pr_debug("setup data transfer: blocksize %08x  nr_blocks %d\n",
                 data->blksz, data->blocks);

        /* Some hardware cannot perform 2 byte requests in 4/8 bit mode */
        if (host->mmc->ios.bus_width == MMC_BUS_WIDTH_4 ||
            host->mmc->ios.bus_width == MMC_BUS_WIDTH_8) {
                int blksz_2bytes = pdata->flags & TMIO_MMC_BLKSZ_2BYTES;

                if (data->blksz < 2 || (data->blksz < 4 && !blksz_2bytes)) {
                        pr_err("%s: %d byte block unsupported in 4/8 bit mode\n",
                               mmc_hostname(host->mmc), data->blksz);
                        return -EINVAL;
                }
        }

        tmio_mmc_init_sg(host, data);
        host->data = data;

        /* Set transfer length / blocksize */
        sd_ctrl_write16(host, CTL_SD_XFER_LEN, data->blksz);
        sd_ctrl_write16(host, CTL_XFER_BLK_COUNT, data->blocks);

        tmio_mmc_start_dma(host, data);

        return 0;
}

static void tmio_mmc_hw_reset(struct mmc_host *mmc)
{
        struct tmio_mmc_host *host = mmc_priv(mmc);

        if (host->hw_reset)
                host->hw_reset(host);
}

static int tmio_mmc_execute_tuning(struct mmc_host *mmc, u32 opcode)
{
        struct tmio_mmc_host *host = mmc_priv(mmc);
        int i, ret = 0;

        if (!host->init_tuning || !host->select_tuning)
                /* Tuning is not supported */
                goto out;

        host->tap_num = host->init_tuning(host);
        if (!host->tap_num)
                /* Tuning is not supported */
                goto out;

        if (host->tap_num * 2 >= sizeof(host->taps) * BITS_PER_BYTE) {
                dev_warn_once(&host->pdev->dev,
                        "Too many taps, skipping tuning. Please consider updating size of taps field of tmio_mmc_host\n");
                goto out;
        }

        bitmap_zero(host->taps, host->tap_num * 2);

        /* Issue CMD19 twice for each tap */
        for (i = 0; i < 2 * host->tap_num; i++) {
                if (host->prepare_tuning)
                        host->prepare_tuning(host, i % host->tap_num);

                ret = mmc_send_tuning(mmc, opcode, NULL);
                if (ret && ret != -EILSEQ)
                        goto out;
                if (ret == 0)
                        set_bit(i, host->taps);

                mdelay(1);
        }

        ret = host->select_tuning(host);

out:
        if (ret < 0) {
                dev_warn(&host->pdev->dev, "Tuning procedure failed\n");
                tmio_mmc_hw_reset(mmc);
        }

        return ret;
}

static void tmio_process_mrq(struct tmio_mmc_host *host,
                             struct mmc_request *mrq)
{
        struct mmc_command *cmd;
        int ret;

        if (mrq->sbc && host->cmd != mrq->sbc) {
                cmd = mrq->sbc;
        } else {
                cmd = mrq->cmd;
                if (mrq->data) {
                        ret = tmio_mmc_start_data(host, mrq->data);
                        if (ret)
                                goto fail;
                }
        }

        ret = tmio_mmc_start_command(host, cmd);
        if (ret)
                goto fail;

        schedule_delayed_work(&host->delayed_reset_work,
                              msecs_to_jiffies(CMDREQ_TIMEOUT));
        return;

fail:
        host->force_pio = false;
        host->mrq = NULL;
        mrq->cmd->error = ret;
        mmc_request_done(host->mmc, mrq);
}

/* Process requests from the MMC layer */
static void tmio_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
        struct tmio_mmc_host *host = mmc_priv(mmc);
        unsigned long flags;

        spin_lock_irqsave(&host->lock, flags);

        if (host->mrq) {
                pr_debug("request not null\n");
                if (IS_ERR(host->mrq)) {
                        spin_unlock_irqrestore(&host->lock, flags);
                        mrq->cmd->error = -EAGAIN;
                        mmc_request_done(mmc, mrq);
                        return;
                }
        }

        host->last_req_ts = jiffies;
        wmb();
        host->mrq = mrq;

        spin_unlock_irqrestore(&host->lock, flags);

        tmio_process_mrq(host, mrq);
}

static void tmio_mmc_finish_request(struct tmio_mmc_host *host)
{
        struct mmc_request *mrq;
        unsigned long flags;

        spin_lock_irqsave(&host->lock, flags);

        mrq = host->mrq;
        if (IS_ERR_OR_NULL(mrq)) {
                spin_unlock_irqrestore(&host->lock, flags);
                return;
        }

        /* If not SET_BLOCK_COUNT, clear old data */
        if (host->cmd != mrq->sbc) {
                host->cmd = NULL;
                host->data = NULL;
                host->force_pio = false;
                host->mrq = NULL;
        }

        cancel_delayed_work(&host->delayed_reset_work);

        spin_unlock_irqrestore(&host->lock, flags);

        if (mrq->cmd->error || (mrq->data && mrq->data->error))
                tmio_mmc_abort_dma(host);

        if (host->check_scc_error)
                host->check_scc_error(host);

        /* If SET_BLOCK_COUNT, continue with main command */
        if (host->mrq) {
                tmio_process_mrq(host, mrq);
                return;
        }

        mmc_request_done(host->mmc, mrq);
}

static void tmio_mmc_done_work(struct work_struct *work)
{
        struct tmio_mmc_host *host = container_of(work, struct tmio_mmc_host,
                                                  done);
        tmio_mmc_finish_request(host);
}

static int tmio_mmc_clk_enable(struct tmio_mmc_host *host)
{
        if (!host->clk_enable)
                return -ENOTSUPP;

        return host->clk_enable(host);
}

static void tmio_mmc_clk_disable(struct tmio_mmc_host *host)
{
        if (host->clk_disable)
                host->clk_disable(host);
}

static void tmio_mmc_power_on(struct tmio_mmc_host *host, unsigned short vdd)
{
        struct mmc_host *mmc = host->mmc;
        int ret = 0;

        /* .set_ios() is returning void, so, no chance to report an error */

        if (host->set_pwr)
                host->set_pwr(host->pdev, 1);

        if (!IS_ERR(mmc->supply.vmmc)) {
                ret = mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
                /*
                 * Attention: empiric value. With a b43 WiFi SDIO card this
                 * delay proved necessary for reliable card-insertion probing.
                 * 100us were not enough. Is this the same 140us delay, as in
                 * tmio_mmc_set_ios()?
                 */
                udelay(200);
        }
        /*
         * It seems, VccQ should be switched on after Vcc, this is also what the
         * omap_hsmmc.c driver does.
         */
        if (!IS_ERR(mmc->supply.vqmmc) && !ret) {
                ret = regulator_enable(mmc->supply.vqmmc);
                udelay(200);
        }

        if (ret < 0)
                dev_dbg(&host->pdev->dev, "Regulators failed to power up: %d\n",
                        ret);
}

static void tmio_mmc_power_off(struct tmio_mmc_host *host)
{
        struct mmc_host *mmc = host->mmc;

        if (!IS_ERR(mmc->supply.vqmmc))
                regulator_disable(mmc->supply.vqmmc);

        if (!IS_ERR(mmc->supply.vmmc))
                mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0);

        if (host->set_pwr)
                host->set_pwr(host->pdev, 0);
}

static void tmio_mmc_set_bus_width(struct tmio_mmc_host *host,
                                   unsigned char bus_width)
{
        u16 reg = sd_ctrl_read16(host, CTL_SD_MEM_CARD_OPT)
                                & ~(CARD_OPT_WIDTH | CARD_OPT_WIDTH8);

        /* reg now applies to MMC_BUS_WIDTH_4 */
        if (bus_width == MMC_BUS_WIDTH_1)
                reg |= CARD_OPT_WIDTH;
        else if (bus_width == MMC_BUS_WIDTH_8)

                reg |= CARD_OPT_WIDTH8;

        sd_ctrl_write16(host, CTL_SD_MEM_CARD_OPT, reg);
}

/* Set MMC clock / power.
 * Note: This controller uses a simple divider scheme therefore it cannot
 * run a MMC card at full speed (20MHz). The max clock is 24MHz on SD, but as
 * MMC wont run that fast, it has to be clocked at 12MHz which is the next
 * slowest setting.
 */
static void tmio_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
        struct tmio_mmc_host *host = mmc_priv(mmc);
        struct device *dev = &host->pdev->dev;
        unsigned long flags;

        mutex_lock(&host->ios_lock);

        spin_lock_irqsave(&host->lock, flags);
        if (host->mrq) {
                if (IS_ERR(host->mrq)) {
                        dev_dbg(dev,
                                "%s.%d: concurrent .set_ios(), clk %u, mode %u\n",
                                current->comm, task_pid_nr(current),
                                ios->clock, ios->power_mode);
                        host->mrq = ERR_PTR(-EINTR);
                } else {
                        dev_dbg(dev,
                                "%s.%d: CMD%u active since %lu, now %lu!\n",
                                current->comm, task_pid_nr(current),
                                host->mrq->cmd->opcode, host->last_req_ts,
                                jiffies);
                }
                spin_unlock_irqrestore(&host->lock, flags);

                mutex_unlock(&host->ios_lock);
                return;
        }

        host->mrq = ERR_PTR(-EBUSY);

        spin_unlock_irqrestore(&host->lock, flags);

        switch (ios->power_mode) {
        case MMC_POWER_OFF:
                tmio_mmc_power_off(host);
                tmio_mmc_clk_stop(host);
                break;
        case MMC_POWER_UP:
                tmio_mmc_power_on(host, ios->vdd);
                tmio_mmc_set_clock(host, ios->clock);
                tmio_mmc_set_bus_width(host, ios->bus_width);
                break;
        case MMC_POWER_ON:
                tmio_mmc_set_clock(host, ios->clock);
                tmio_mmc_set_bus_width(host, ios->bus_width);
                break;
        }

        /* Let things settle. delay taken from winCE driver */
        udelay(140);
        if (PTR_ERR(host->mrq) == -EINTR)
                dev_dbg(&host->pdev->dev,
                        "%s.%d: IOS interrupted: clk %u, mode %u",
                        current->comm, task_pid_nr(current),
                        ios->clock, ios->power_mode);
        host->mrq = NULL;

        host->clk_cache = ios->clock;

        mutex_unlock(&host->ios_lock);
}

static int tmio_mmc_get_ro(struct mmc_host *mmc)
{
        struct tmio_mmc_host *host = mmc_priv(mmc);
        struct tmio_mmc_data *pdata = host->pdata;
        int ret = mmc_gpio_get_ro(mmc);

        if (ret >= 0)
                return ret;

        ret = !((pdata->flags & TMIO_MMC_WRPROTECT_DISABLE) ||
                (sd_ctrl_read16_and_16_as_32(host, CTL_STATUS) & TMIO_STAT_WRPROTECT));

        return ret;
}

static int tmio_multi_io_quirk(struct mmc_card *card,
                               unsigned int direction, int blk_size)
{
        struct tmio_mmc_host *host = mmc_priv(card->host);

        if (host->multi_io_quirk)
                return host->multi_io_quirk(card, direction, blk_size);

        return blk_size;
}

static struct mmc_host_ops tmio_mmc_ops = {
        .request        = tmio_mmc_request,
        .set_ios        = tmio_mmc_set_ios,
        .get_ro         = tmio_mmc_get_ro,
        .get_cd         = mmc_gpio_get_cd,
        .enable_sdio_irq = tmio_mmc_enable_sdio_irq,
        .multi_io_quirk = tmio_multi_io_quirk,
        .hw_reset       = tmio_mmc_hw_reset,
        .execute_tuning = tmio_mmc_execute_tuning,
};

static int tmio_mmc_init_ocr(struct tmio_mmc_host *host)
{
        struct tmio_mmc_data *pdata = host->pdata;
        struct mmc_host *mmc = host->mmc;
        int err;

        err = mmc_regulator_get_supply(mmc);
        if (err)
                return err;

        /* use ocr_mask if no regulator */
        if (!mmc->ocr_avail)
                mmc->ocr_avail =  pdata->ocr_mask;

        /*
         * try again.
         * There is possibility that regulator has not been probed
         */
        if (!mmc->ocr_avail)
                return -EPROBE_DEFER;

        return 0;
}

static void tmio_mmc_of_parse(struct platform_device *pdev,
                              struct tmio_mmc_data *pdata)
{
        const struct device_node *np = pdev->dev.of_node;

        if (!np)
                return;

        if (of_get_property(np, "toshiba,mmc-wrprotect-disable", NULL))
                pdata->flags |= TMIO_MMC_WRPROTECT_DISABLE;
}

struct tmio_mmc_host*
tmio_mmc_host_alloc(struct platform_device *pdev)
{
        struct tmio_mmc_host *host;
        struct mmc_host *mmc;

        mmc = mmc_alloc_host(sizeof(struct tmio_mmc_host), &pdev->dev);
        if (!mmc)
                return NULL;

        host = mmc_priv(mmc);
        host->mmc = mmc;
        host->pdev = pdev;

        return host;
}
EXPORT_SYMBOL_GPL(tmio_mmc_host_alloc);

void tmio_mmc_host_free(struct tmio_mmc_host *host)
{
        mmc_free_host(host->mmc);
}
EXPORT_SYMBOL_GPL(tmio_mmc_host_free);

int tmio_mmc_host_probe(struct tmio_mmc_host *_host,
                        struct tmio_mmc_data *pdata,
                        const struct tmio_mmc_dma_ops *dma_ops)
{
        struct platform_device *pdev = _host->pdev;
        struct mmc_host *mmc = _host->mmc;
        struct resource *res_ctl;
        int ret;
        u32 irq_mask = TMIO_MASK_CMD;

        tmio_mmc_of_parse(pdev, pdata);

        if (!(pdata->flags & TMIO_MMC_HAS_IDLE_WAIT))
                _host->write16_hook = NULL;

        res_ctl = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res_ctl)
                return -EINVAL;

        ret = mmc_of_parse(mmc);
        if (ret < 0)
                return ret;

        _host->pdata = pdata;
        platform_set_drvdata(pdev, mmc);

        _host->set_pwr = pdata->set_pwr;
        _host->set_clk_div = pdata->set_clk_div;

        ret = tmio_mmc_init_ocr(_host);
        if (ret < 0)
                return ret;

        _host->ctl = devm_ioremap(&pdev->dev,
                                  res_ctl->start, resource_size(res_ctl));
        if (!_host->ctl)
                return -ENOMEM;

        tmio_mmc_ops.card_busy = _host->card_busy;
        tmio_mmc_ops.start_signal_voltage_switch =
                _host->start_signal_voltage_switch;
        mmc->ops = &tmio_mmc_ops;

        mmc->caps |= MMC_CAP_4_BIT_DATA | pdata->capabilities;
        mmc->caps2 |= pdata->capabilities2;
        mmc->max_segs = pdata->max_segs ? : 32;
        mmc->max_blk_size = 512;
        mmc->max_blk_count = pdata->max_blk_count ? :
                (PAGE_SIZE / mmc->max_blk_size) * mmc->max_segs;
        mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count;
        /*
         * Since swiotlb has memory size limitation, this will calculate
         * the maximum size locally (because we don't have any APIs for it now)
         * and check the current max_req_size. And then, this will update
         * the max_req_size if needed as a workaround.
         */
        if (swiotlb_max_segment()) {
                unsigned int max_size = (1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;

                if (mmc->max_req_size > max_size)
                        mmc->max_req_size = max_size;
        }
        mmc->max_seg_size = mmc->max_req_size;

        _host->native_hotplug = !(pdata->flags & TMIO_MMC_USE_GPIO_CD ||
                                  mmc->caps & MMC_CAP_NEEDS_POLL ||
                                  !mmc_card_is_removable(mmc));

        /*
         * On Gen2+, eMMC with NONREMOVABLE currently fails because native
         * hotplug gets disabled. It seems RuntimePM related yet we need further
         * research. Since we are planning a PM overhaul anyway, let's enforce
         * for now the device being active by enabling native hotplug always.
         */
        if (pdata->flags & TMIO_MMC_MIN_RCAR2)
                _host->native_hotplug = true;

        if (tmio_mmc_clk_enable(_host) < 0) {
                mmc->f_max = pdata->hclk;
                mmc->f_min = mmc->f_max / 512;
        }

        /*
         * Check the sanity of mmc->f_min to prevent tmio_mmc_set_clock() from
         * looping forever...
         */
        if (mmc->f_min == 0)
                return -EINVAL;

        /*
         * While using internal tmio hardware logic for card detection, we need
         * to ensure it stays powered for it to work.
         */
        if (_host->native_hotplug)
                pm_runtime_get_noresume(&pdev->dev);

        _host->sdio_irq_enabled = false;
        if (pdata->flags & TMIO_MMC_SDIO_IRQ)
                _host->sdio_irq_mask = TMIO_SDIO_MASK_ALL;

        tmio_mmc_clk_stop(_host);
        tmio_mmc_reset(_host);

        _host->sdcard_irq_mask = sd_ctrl_read16_and_16_as_32(_host, CTL_IRQ_MASK);
        tmio_mmc_disable_mmc_irqs(_host, TMIO_MASK_ALL);

        /* Unmask the IRQs we want to know about */
        if (!_host->chan_rx)
                irq_mask |= TMIO_MASK_READOP;
        if (!_host->chan_tx)
                irq_mask |= TMIO_MASK_WRITEOP;
        if (!_host->native_hotplug)
                irq_mask &= ~(TMIO_STAT_CARD_REMOVE | TMIO_STAT_CARD_INSERT);

        _host->sdcard_irq_mask &= ~irq_mask;

        spin_lock_init(&_host->lock);
        mutex_init(&_host->ios_lock);

        /* Init delayed work for request timeouts */
        INIT_DELAYED_WORK(&_host->delayed_reset_work, tmio_mmc_reset_work);
        INIT_WORK(&_host->done, tmio_mmc_done_work);

        /* See if we also get DMA */
        _host->dma_ops = dma_ops;
        tmio_mmc_request_dma(_host, pdata);

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

        ret = mmc_add_host(mmc);
        if (ret)
                goto remove_host;

        dev_pm_qos_expose_latency_limit(&pdev->dev, 100);

        if (pdata->flags & TMIO_MMC_USE_GPIO_CD) {
                ret = mmc_gpio_request_cd(mmc, pdata->cd_gpio, 0);
                if (ret)
                        goto remove_host;

                mmc_gpiod_request_cd_irq(mmc);
        }

        return 0;

remove_host:
        tmio_mmc_host_remove(_host);
        return ret;
}
EXPORT_SYMBOL_GPL(tmio_mmc_host_probe);

void tmio_mmc_host_remove(struct tmio_mmc_host *host)
{
        struct platform_device *pdev = host->pdev;
        struct mmc_host *mmc = host->mmc;

        if (host->pdata->flags & TMIO_MMC_SDIO_IRQ)
                sd_ctrl_write16(host, CTL_TRANSACTION_CTL, 0x0000);

        if (!host->native_hotplug)
                pm_runtime_get_sync(&pdev->dev);

        dev_pm_qos_hide_latency_limit(&pdev->dev);

        mmc_remove_host(mmc);
        cancel_work_sync(&host->done);
        cancel_delayed_work_sync(&host->delayed_reset_work);
        tmio_mmc_release_dma(host);

        pm_runtime_put_sync(&pdev->dev);
        pm_runtime_disable(&pdev->dev);

        tmio_mmc_clk_disable(host);
}
EXPORT_SYMBOL_GPL(tmio_mmc_host_remove);

#ifdef CONFIG_PM
int tmio_mmc_host_runtime_suspend(struct device *dev)
{
        struct mmc_host *mmc = dev_get_drvdata(dev);
        struct tmio_mmc_host *host = mmc_priv(mmc);

        tmio_mmc_disable_mmc_irqs(host, TMIO_MASK_ALL);

        if (host->clk_cache)
                tmio_mmc_clk_stop(host);

        tmio_mmc_clk_disable(host);

        return 0;
}
EXPORT_SYMBOL_GPL(tmio_mmc_host_runtime_suspend);

static bool tmio_mmc_can_retune(struct tmio_mmc_host *host)
{
        return host->tap_num && mmc_can_retune(host->mmc);
}

int tmio_mmc_host_runtime_resume(struct device *dev)
{
        struct mmc_host *mmc = dev_get_drvdata(dev);
        struct tmio_mmc_host *host = mmc_priv(mmc);

        tmio_mmc_reset(host);
        tmio_mmc_clk_enable(host);

        if (host->clk_cache)
                tmio_mmc_set_clock(host, host->clk_cache);

        tmio_mmc_enable_dma(host, true);

        if (tmio_mmc_can_retune(host) && host->select_tuning(host))
                dev_warn(&host->pdev->dev, "Tuning selection failed\n");

        return 0;
}
EXPORT_SYMBOL_GPL(tmio_mmc_host_runtime_resume);
#endif

MODULE_LICENSE("GPL v2");