tmio_mmc_pio.c

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/*
 * linux/drivers/mmc/host/tmio_mmc_pio.c
 *
 * 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.
 *
 * Driver for the MMC / SD / SDIO IP found in:
 *
 * TC6393XB, TC6391XB, TC6387XB, T7L66XB, ASIC3, SH-Mobile SoCs
 *
 * 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
 *   SDIO support
 *   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/host.h>
#include <linux/mmc/mmc.h>
#include <linux/mmc/slot-gpio.h>
#include <linux/mmc/tmio.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/scatterlist.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>

#include "tmio_mmc.h"

void tmio_mmc_enable_mmc_irqs(struct tmio_mmc_host *host, u32 i)
{
    host->sdcard_irq_mask &= ~(i & TMIO_MASK_IRQ);
    sd_ctrl_write32(host, CTL_IRQ_MASK, host->sdcard_irq_mask);
}

void tmio_mmc_disable_mmc_irqs(struct tmio_mmc_host *host, u32 i)
{
    host->sdcard_irq_mask |= (i & TMIO_MASK_IRQ);
    sd_ctrl_write32(host, CTL_IRQ_MASK, host->sdcard_irq_mask);
}

static void tmio_mmc_ack_mmc_irqs(struct tmio_mmc_host *host, u32 i)
{
    sd_ctrl_write32(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;
}

#ifdef CONFIG_MMC_DEBUG

#define STATUS_TO_TEXT(a, status, i) \
    do { \
        if (status & TMIO_STAT_##a) { \
            if (i++) \
                printk(" | "); \
            printk(#a); \
        } \
    } while (0)

static void pr_debug_status(u32 status)
{
    int i = 0;
    pr_debug("status: %08x = ", status);
    STATUS_TO_TEXT(CARD_REMOVE, status, i);
    STATUS_TO_TEXT(CARD_INSERT, status, i);
    STATUS_TO_TEXT(SIGSTATE, status, i);
    STATUS_TO_TEXT(WRPROTECT, status, i);
    STATUS_TO_TEXT(CARD_REMOVE_A, status, i);
    STATUS_TO_TEXT(CARD_INSERT_A, status, i);
    STATUS_TO_TEXT(SIGSTATE_A, status, i);
    STATUS_TO_TEXT(CMD_IDX_ERR, status, i);
    STATUS_TO_TEXT(STOPBIT_ERR, status, i);
    STATUS_TO_TEXT(ILL_FUNC, status, i);
    STATUS_TO_TEXT(CMD_BUSY, status, i);
    STATUS_TO_TEXT(CMDRESPEND, status, i);
    STATUS_TO_TEXT(DATAEND, status, i);
    STATUS_TO_TEXT(CRCFAIL, status, i);
    STATUS_TO_TEXT(DATATIMEOUT, status, i);
    STATUS_TO_TEXT(CMDTIMEOUT, status, i);
    STATUS_TO_TEXT(RXOVERFLOW, status, i);
    STATUS_TO_TEXT(TXUNDERRUN, status, i);
    STATUS_TO_TEXT(RXRDY, status, i);
    STATUS_TO_TEXT(TXRQ, status, i);
    STATUS_TO_TEXT(ILL_ACCESS, status, i);
    printk("\n");
}

#else
#define pr_debug_status(s)  do { } while (0)
#endif

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_mask = TMIO_SDIO_MASK_ALL &
                    ~TMIO_SDIO_STAT_IOIRQ;
        sd_ctrl_write16(host, CTL_TRANSACTION_CTL, 0x0001);
        sd_ctrl_write16(host, CTL_SDIO_IRQ_MASK, host->sdio_irq_mask);
    } else {
        host->sdio_irq_mask = TMIO_SDIO_MASK_ALL;
        sd_ctrl_write16(host, CTL_SDIO_IRQ_MASK, host->sdio_irq_mask);
        sd_ctrl_write16(host, CTL_TRANSACTION_CTL, 0x0000);
    }
}

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

    if (new_clock) {
        for (clock = host->mmc->f_min, clk = 0x80000080;
            new_clock >= (clock<<1); clk >>= 1)
            clock <<= 1;
        clk |= 0x100;
    }

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

    sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, clk & 0x1ff);
}

static void tmio_mmc_clk_stop(struct tmio_mmc_host *host)
{
    struct resource *res = platform_get_resource(host->pdev, IORESOURCE_MEM, 0);

    /* implicit BUG_ON(!res) */
    if (resource_size(res) > 0x100) {
        sd_ctrl_write16(host, CTL_CLK_AND_WAIT_CTL, 0x0000);
        msleep(10);
    }

    sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~0x0100 &
        sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
    msleep(10);
}

static void tmio_mmc_clk_start(struct tmio_mmc_host *host)
{
    struct resource *res = platform_get_resource(host->pdev, IORESOURCE_MEM, 0);

    sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, 0x0100 |
        sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
    msleep(10);

    /* implicit BUG_ON(!res) */
    if (resource_size(res) > 0x100) {
        sd_ctrl_write16(host, CTL_CLK_AND_WAIT_CTL, 0x0100);
        msleep(10);
    }
}

static void tmio_mmc_reset(struct tmio_mmc_host *host)
{
    struct resource *res = platform_get_resource(host->pdev, IORESOURCE_MEM, 0);

    /* FIXME - should we set stop clock reg here */
    sd_ctrl_write16(host, CTL_RESET_SD, 0x0000);
    /* implicit BUG_ON(!res) */
    if (resource_size(res) > 0x100)
        sd_ctrl_write16(host, CTL_RESET_SDIO, 0x0000);
    msleep(10);
    sd_ctrl_write16(host, CTL_RESET_SD, 0x0001);
    if (resource_size(res) > 0x100)
        sd_ctrl_write16(host, CTL_RESET_SDIO, 0x0001);
    msleep(10);
}

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(2000))) {
        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);
}

/* called with host->lock held, interrupts disabled */
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;
    }

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

    cancel_delayed_work(&host->delayed_reset_work);

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

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

    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);
}

/* 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

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;

    /* CMD12 is handled by hardware */
    if (cmd->opcode == MMC_STOP_TRANSMISSION && !cmd->arg) {
        sd_ctrl_write16(host, CTL_STOP_INTERNAL_ACTION, 0x001);
        return 0;
    }

    switch (mmc_resp_type(cmd)) {
    case MMC_RSP_NONE: c |= RESP_NONE; break;
    case MMC_RSP_R1:   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, 0x100);
            c |= TRANSFER_MULTI;
        }
        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(host, CTL_ARG_REG, cmd->arg);
    sd_ctrl_write16(host, CTL_SD_CMD, c);

    return 0;
}

/*
 * 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 */
    if (data->flags & MMC_DATA_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);

    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);

    return;
}

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) {
        if (stop->opcode == MMC_STOP_TRANSMISSION && !stop->arg)
            sd_ctrl_write16(host, CTL_STOP_INTERNAL_ACTION, 0x000);
        else
            BUG();
    }

    schedule_work(&host->done);
}

static void tmio_mmc_data_irq(struct tmio_mmc_host *host)
{
    struct mmc_data *data;
    spin_lock(&host->lock);
    data = host->data;

    if (!data)
        goto out;

    if (host->chan_tx && (data->flags & MMC_DATA_WRITE) && !host->force_pio) {
        /*
         * 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 (!(sd_ctrl_read32(host, CTL_STATUS) & TMIO_STAT_CMD_BUSY)) {
            tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_DATAEND);
            tasklet_schedule(&host->dma_complete);
        }
    } else if (host->chan_rx && (data->flags & MMC_DATA_READ) && !host->force_pio) {
        tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_DATAEND);
        tasklet_schedule(&host->dma_complete);
    } 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;
    }

    host->cmd = NULL;

    /* 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_read32(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)
        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) {
        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 void tmio_mmc_card_irq_status(struct tmio_mmc_host *host,
                       int *ireg, int *status)
{
    *status = sd_ctrl_read32(host, CTL_STATUS);
    *ireg = *status & TMIO_MASK_IRQ & ~host->sdcard_irq_mask;

    pr_debug_status(*status);
    pr_debug_status(*ireg);
}

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;
}

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

    tmio_mmc_card_irq_status(host, &ireg, &status);
    __tmio_mmc_card_detect_irq(host, ireg, status);

    return IRQ_HANDLED;
}
EXPORT_SYMBOL(tmio_mmc_card_detect_irq);

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);
        return true;
    }

    return false;
}

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

    tmio_mmc_card_irq_status(host, &ireg, &status);
    __tmio_mmc_sdcard_irq(host, ireg, status);

    return IRQ_HANDLED;
}
EXPORT_SYMBOL(tmio_mmc_sdcard_irq);

irqreturn_t tmio_mmc_sdio_irq(int irq, void *devid)
{
    struct tmio_mmc_host *host = devid;
    struct mmc_host *mmc = host->mmc;
    struct tmio_mmc_data *pdata = host->pdata;
    unsigned int ireg, status;

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

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

    sd_ctrl_write16(host, CTL_SDIO_STATUS, status & ~TMIO_SDIO_MASK_ALL);

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

    return IRQ_HANDLED;
}
EXPORT_SYMBOL(tmio_mmc_sdio_irq);

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

    pr_debug("MMC IRQ begin\n");

    tmio_mmc_card_irq_status(host, &ireg, &status);
    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(irq, devid);

    return IRQ_HANDLED;
}
EXPORT_SYMBOL(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 bit mode */
    if (host->mmc->ios.bus_width == MMC_BUS_WIDTH_4) {
        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 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;
}

/* 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;
    int ret;

    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);

    if (mrq->data) {
        ret = tmio_mmc_start_data(host, mrq->data);
        if (ret)
            goto fail;
    }

    ret = tmio_mmc_start_command(host, mrq->cmd);
    if (!ret) {
        schedule_delayed_work(&host->delayed_reset_work,
                      msecs_to_jiffies(2000));
        return;
    }

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

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

    if (!pdata->clk_enable)
        return -ENOTSUPP;

    ret = pdata->clk_enable(host->pdev, &mmc->f_max);
    if (!ret)
        mmc->f_min = mmc->f_max / 512;

    return ret;
}

static void tmio_mmc_set_power(struct tmio_mmc_host *host, struct mmc_ios *ios)
{
    struct mmc_host *mmc = host->mmc;

    if (host->set_pwr)
        host->set_pwr(host->pdev, ios->power_mode != MMC_POWER_OFF);
    if (!IS_ERR(mmc->supply.vmmc))
        /* Errors ignored... */
        mmc_regulator_set_ocr(mmc, mmc->supply.vmmc,
                      ios->power_mode ? ios->vdd : 0);
}

/* 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);

    /*
     * host->power toggles between false and true in both cases - either
     * or not the controller can be runtime-suspended during inactivity.
     * But if the controller has to be kept on, the runtime-pm usage_count
     * is kept positive, so no suspending actually takes place.
     */
    if (ios->power_mode == MMC_POWER_ON && ios->clock) {
        if (!host->power) {
            tmio_mmc_clk_update(mmc);
            pm_runtime_get_sync(dev);
            host->power = true;
        }
        tmio_mmc_set_clock(host, ios->clock);
        /* power up SD bus */
        tmio_mmc_set_power(host, ios);
        /* start bus clock */
        tmio_mmc_clk_start(host);
    } else if (ios->power_mode != MMC_POWER_UP) {
        if (ios->power_mode == MMC_POWER_OFF)
            tmio_mmc_set_power(host, ios);
        if (host->power) {
            struct tmio_mmc_data *pdata = host->pdata;
            tmio_mmc_clk_stop(host);
            host->power = false;
            pm_runtime_put(dev);
            if (pdata->clk_disable)
                pdata->clk_disable(host->pdev);
        }
    }

    if (host->power) {
        switch (ios->bus_width) {
        case MMC_BUS_WIDTH_1:
            sd_ctrl_write16(host, CTL_SD_MEM_CARD_OPT, 0x80e0);
        break;
        case MMC_BUS_WIDTH_4:
            sd_ctrl_write16(host, CTL_SD_MEM_CARD_OPT, 0x00e0);
        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;

    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;

    return !((pdata->flags & TMIO_MMC_WRPROTECT_DISABLE) ||
         (sd_ctrl_read32(host, CTL_STATUS) & TMIO_STAT_WRPROTECT));
}

static int tmio_mmc_get_cd(struct mmc_host *mmc)
{
    struct tmio_mmc_host *host = mmc_priv(mmc);
    struct tmio_mmc_data *pdata = host->pdata;
    int ret = mmc_gpio_get_cd(mmc);
    if (ret >= 0)
        return ret;

    if (!pdata->get_cd)
        return -ENOSYS;
    else
        return pdata->get_cd(host->pdev);
}

static const 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     = tmio_mmc_get_cd,
    .enable_sdio_irq = tmio_mmc_enable_sdio_irq,
};

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

    mmc_regulator_get_supply(mmc);

    if (!mmc->ocr_avail)
        mmc->ocr_avail = pdata->ocr_mask ? : MMC_VDD_32_33 | MMC_VDD_33_34;
    else if (pdata->ocr_mask)
        dev_warn(mmc_dev(mmc), "Platform OCR mask is ignored\n");
}

int __devinit tmio_mmc_host_probe(struct tmio_mmc_host **host,
                  struct platform_device *pdev,
                  struct tmio_mmc_data *pdata)
{
    struct tmio_mmc_host *_host;
    struct mmc_host *mmc;
    struct resource *res_ctl;
    int ret;
    u32 irq_mask = TMIO_MASK_CMD;

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

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

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

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

    /* SD control register space size is 0x200, 0x400 for bus_shift=1 */
    _host->bus_shift = resource_size(res_ctl) >> 10;

    _host->ctl = ioremap(res_ctl->start, resource_size(res_ctl));
    if (!_host->ctl) {
        ret = -ENOMEM;
        goto host_free;
    }

    mmc->ops = &tmio_mmc_ops;
    mmc->caps = MMC_CAP_4_BIT_DATA | pdata->capabilities;
    mmc->caps2 = pdata->capabilities2;
    mmc->max_segs = 32;
    mmc->max_blk_size = 512;
    mmc->max_blk_count = (PAGE_CACHE_SIZE / mmc->max_blk_size) *
        mmc->max_segs;
    mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count;
    mmc->max_seg_size = mmc->max_req_size;
    tmio_mmc_init_ocr(_host);

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

    _host->power = false;
    pm_runtime_enable(&pdev->dev);
    ret = pm_runtime_resume(&pdev->dev);
    if (ret < 0)
        goto pm_disable;

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

    /*
     * There are 4 different scenarios for the card detection:
     *  1) an external gpio irq handles the cd (best for power savings)
     *  2) internal sdhi irq handles the cd
     *  3) a worker thread polls the sdhi - indicated by MMC_CAP_NEEDS_POLL
     *  4) the medium is non-removable - indicated by MMC_CAP_NONREMOVABLE
     *
     *  While we increment the runtime PM counter for all scenarios when
     *  the mmc core activates us by calling an appropriate set_ios(), we
     *  must additionally ensure that in case 2) the tmio mmc hardware stays
     *  powered on during runtime for the card detection to work.
     */
    if (_host->native_hotplug)
        pm_runtime_get_noresume(&pdev->dev);

    tmio_mmc_clk_stop(_host);
    tmio_mmc_reset(_host);

    _host->sdcard_irq_mask = sd_ctrl_read32(_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;

    if (pdata->flags & TMIO_MMC_SDIO_IRQ)
        tmio_mmc_enable_sdio_irq(mmc, 0);

    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 */
    tmio_mmc_request_dma(_host, pdata);

    ret = mmc_add_host(mmc);
    if (pdata->clk_disable)
        pdata->clk_disable(pdev);
    if (ret < 0) {
        tmio_mmc_host_remove(_host);
        return ret;
    }

    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);
        if (ret < 0) {
            tmio_mmc_host_remove(_host);
            return ret;
        }
    }

    *host = _host;

    return 0;

pm_disable:
    pm_runtime_disable(&pdev->dev);
    iounmap(_host->ctl);
host_free:
    mmc_free_host(mmc);

    return ret;
}
EXPORT_SYMBOL(tmio_mmc_host_probe);

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

    if (pdata->flags & TMIO_MMC_USE_GPIO_CD)
        /*
         * This means we can miss a card-eject, but this is anyway
         * possible, because of delayed processing of hotplug events.
         */
        mmc_gpio_free_cd(mmc);

    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);

    iounmap(host->ctl);
    mmc_free_host(mmc);
}
EXPORT_SYMBOL(tmio_mmc_host_remove);

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

    if (!ret)
        tmio_mmc_disable_mmc_irqs(host, TMIO_MASK_ALL);

    return ret;
}
EXPORT_SYMBOL(tmio_mmc_host_suspend);

int tmio_mmc_host_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_enable_dma(host, true);

    /* The MMC core will perform the complete set up */
    return mmc_resume_host(mmc);
}
EXPORT_SYMBOL(tmio_mmc_host_resume);

#endif  /* CONFIG_PM */

int tmio_mmc_host_runtime_suspend(struct device *dev)
{
    return 0;
}
EXPORT_SYMBOL(tmio_mmc_host_runtime_suspend);

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_enable_dma(host, true);

    return 0;
}
EXPORT_SYMBOL(tmio_mmc_host_runtime_resume);

MODULE_LICENSE("GPL v2");