/*
 * Atmel MultiMedia Card Interface driver
 *
 * Copyright (C) 2004-2008 Atmel Corporation
 *
 * 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.
 */
#include <linux/blkdev.h>
#include <linux/clk.h>
#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/platform_device.h>
#include <linux/scatterlist.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/types.h>
#include <linux/platform_data/atmel.h>

#include <linux/mmc/host.h>
#include <linux/mmc/sdio.h>

#include <mach/atmel-mci.h>
#include <linux/atmel-mci.h>
#include <linux/atmel_pdc.h>

#include <asm/io.h>
#include <asm/unaligned.h>

#include "atmel-mci-regs.h"

#define ATMCI_DATA_ERROR_FLAGS  (ATMCI_DCRCE | ATMCI_DTOE | ATMCI_OVRE | ATMCI_UNRE)
#define ATMCI_DMA_THRESHOLD     16

enum {
        EVENT_CMD_RDY = 0,
        EVENT_XFER_COMPLETE,
        EVENT_NOTBUSY,
        EVENT_DATA_ERROR,
};

enum atmel_mci_state {
        STATE_IDLE = 0,
        STATE_SENDING_CMD,
        STATE_DATA_XFER,
        STATE_WAITING_NOTBUSY,
        STATE_SENDING_STOP,
        STATE_END_REQUEST,
};

enum atmci_xfer_dir {
        XFER_RECEIVE = 0,
        XFER_TRANSMIT,
};

enum atmci_pdc_buf {
        PDC_FIRST_BUF = 0,
        PDC_SECOND_BUF,
};

struct atmel_mci_caps {
        bool    has_dma_conf_reg;
        bool    has_pdc;
        bool    has_cfg_reg;
        bool    has_cstor_reg;
        bool    has_highspeed;
        bool    has_rwproof;
        bool    has_odd_clk_div;
        bool    has_bad_data_ordering;
        bool    need_reset_after_xfer;
        bool    need_blksz_mul_4;
        bool    need_notbusy_for_read_ops;
};

struct atmel_mci_dma {
        struct dma_chan                 *chan;
        struct dma_async_tx_descriptor  *data_desc;
};

/**
 * struct atmel_mci - MMC controller state shared between all slots
 * @lock: Spinlock protecting the queue and associated data.
 * @regs: Pointer to MMIO registers.
 * @sg: Scatterlist entry currently being processed by PIO or PDC code.
 * @pio_offset: Offset into the current scatterlist entry.
 * @buffer: Buffer used if we don't have the r/w proof capability. We
 *      don't have the time to switch pdc buffers so we have to use only
 *      one buffer for the full transaction.
 * @buf_size: size of the buffer.
 * @phys_buf_addr: buffer address needed for pdc.
 * @cur_slot: The slot which is currently using the controller.
 * @mrq: The request currently being processed on @cur_slot,
 *      or NULL if the controller is idle.
 * @cmd: The command currently being sent to the card, or NULL.
 * @data: The data currently being transferred, or NULL if no data
 *      transfer is in progress.
 * @data_size: just data->blocks * data->blksz.
 * @dma: DMA client state.
 * @data_chan: DMA channel being used for the current data transfer.
 * @cmd_status: Snapshot of SR taken upon completion of the current
 *      command. Only valid when EVENT_CMD_COMPLETE is pending.
 * @data_status: Snapshot of SR taken upon completion of the current
 *      data transfer. Only valid when EVENT_DATA_COMPLETE or
 *      EVENT_DATA_ERROR is pending.
 * @stop_cmdr: Value to be loaded into CMDR when the stop command is
 *      to be sent.
 * @tasklet: Tasklet running the request state machine.
 * @pending_events: Bitmask of events flagged by the interrupt handler
 *      to be processed by the tasklet.
 * @completed_events: Bitmask of events which the state machine has
 *      processed.
 * @state: Tasklet state.
 * @queue: List of slots waiting for access to the controller.
 * @need_clock_update: Update the clock rate before the next request.
 * @need_reset: Reset controller before next request.
 * @timer: Timer to balance the data timeout error flag which cannot rise.
 * @mode_reg: Value of the MR register.
 * @cfg_reg: Value of the CFG register.
 * @bus_hz: The rate of @mck in Hz. This forms the basis for MMC bus
 *      rate and timeout calculations.
 * @mapbase: Physical address of the MMIO registers.
 * @mck: The peripheral bus clock hooked up to the MMC controller.
 * @pdev: Platform device associated with the MMC controller.
 * @slot: Slots sharing this MMC controller.
 * @caps: MCI capabilities depending on MCI version.
 * @prepare_data: function to setup MCI before data transfer which
 * depends on MCI capabilities.
 * @submit_data: function to start data transfer which depends on MCI
 * capabilities.
 * @stop_transfer: function to stop data transfer which depends on MCI
 * capabilities.
 *
 * Locking
 * =======
 *
 * @lock is a softirq-safe spinlock protecting @queue as well as
 * @cur_slot, @mrq and @state. These must always be updated
 * at the same time while holding @lock.
 *
 * @lock also protects mode_reg and need_clock_update since these are
 * used to synchronize mode register updates with the queue
 * processing.
 *
 * The @mrq field of struct atmel_mci_slot is also protected by @lock,
 * and must always be written at the same time as the slot is added to
 * @queue.
 *
 * @pending_events and @completed_events are accessed using atomic bit
 * operations, so they don't need any locking.
 *
 * None of the fields touched by the interrupt handler need any
 * locking. However, ordering is important: Before EVENT_DATA_ERROR or
 * EVENT_DATA_COMPLETE is set in @pending_events, all data-related
 * interrupts must be disabled and @data_status updated with a
 * snapshot of SR. Similarly, before EVENT_CMD_COMPLETE is set, the
 * CMDRDY interrupt must be disabled and @cmd_status updated with a
 * snapshot of SR, and before EVENT_XFER_COMPLETE can be set, the
 * bytes_xfered field of @data must be written. This is ensured by
 * using barriers.
 */
struct atmel_mci {
        spinlock_t              lock;
        void __iomem            *regs;

        struct scatterlist      *sg;
        unsigned int            sg_len;
        unsigned int            pio_offset;
        unsigned int            *buffer;
        unsigned int            buf_size;
        dma_addr_t              buf_phys_addr;

        struct atmel_mci_slot   *cur_slot;
        struct mmc_request      *mrq;
        struct mmc_command      *cmd;
        struct mmc_data         *data;
        unsigned int            data_size;

        struct atmel_mci_dma    dma;
        struct dma_chan         *data_chan;
        struct dma_slave_config dma_conf;

        u32                     cmd_status;
        u32                     data_status;
        u32                     stop_cmdr;

        struct tasklet_struct   tasklet;
        unsigned long           pending_events;
        unsigned long           completed_events;
        enum atmel_mci_state    state;
        struct list_head        queue;

        bool                    need_clock_update;
        bool                    need_reset;
        struct timer_list       timer;
        u32                     mode_reg;
        u32                     cfg_reg;
        unsigned long           bus_hz;
        unsigned long           mapbase;
        struct clk              *mck;
        struct platform_device  *pdev;

        struct atmel_mci_slot   *slot[ATMCI_MAX_NR_SLOTS];

        struct atmel_mci_caps   caps;

        u32 (*prepare_data)(struct atmel_mci *host, struct mmc_data *data);
        void (*submit_data)(struct atmel_mci *host, struct mmc_data *data);
        void (*stop_transfer)(struct atmel_mci *host);
};

/**
 * struct atmel_mci_slot - MMC slot state
 * @mmc: The mmc_host representing this slot.
 * @host: The MMC controller this slot is using.
 * @sdc_reg: Value of SDCR to be written before using this slot.
 * @sdio_irq: SDIO irq mask for this slot.
 * @mrq: mmc_request currently being processed or waiting to be
 *      processed, or NULL when the slot is idle.
 * @queue_node: List node for placing this node in the @queue list of
 *      &struct atmel_mci.
 * @clock: Clock rate configured by set_ios(). Protected by host->lock.
 * @flags: Random state bits associated with the slot.
 * @detect_pin: GPIO pin used for card detection, or negative if not
 *      available.
 * @wp_pin: GPIO pin used for card write protect sending, or negative
 *      if not available.
 * @detect_is_active_high: The state of the detect pin when it is active.
 * @detect_timer: Timer used for debouncing @detect_pin interrupts.
 */
struct atmel_mci_slot {
        struct mmc_host         *mmc;
        struct atmel_mci        *host;

        u32                     sdc_reg;
        u32                     sdio_irq;

        struct mmc_request      *mrq;
        struct list_head        queue_node;

        unsigned int            clock;
        unsigned long           flags;
#define ATMCI_CARD_PRESENT      0
#define ATMCI_CARD_NEED_INIT    1
#define ATMCI_SHUTDOWN          2
#define ATMCI_SUSPENDED         3

        int                     detect_pin;
        int                     wp_pin;
        bool                    detect_is_active_high;

        struct timer_list       detect_timer;
};

#define atmci_test_and_clear_pending(host, event)               \
        test_and_clear_bit(event, &host->pending_events)
#define atmci_set_completed(host, event)                        \
        set_bit(event, &host->completed_events)
#define atmci_set_pending(host, event)                          \
        set_bit(event, &host->pending_events)

/*
 * The debugfs stuff below is mostly optimized away when
 * CONFIG_DEBUG_FS is not set.
 */
static int atmci_req_show(struct seq_file *s, void *v)
{
        struct atmel_mci_slot   *slot = s->private;
        struct mmc_request      *mrq;
        struct mmc_command      *cmd;
        struct mmc_command      *stop;
        struct mmc_data         *data;

        /* Make sure we get a consistent snapshot */
        spin_lock_bh(&slot->host->lock);
        mrq = slot->mrq;

        if (mrq) {
                cmd = mrq->cmd;
                data = mrq->data;
                stop = mrq->stop;

                if (cmd)
                        seq_printf(s,
                                "CMD%u(0x%x) flg %x rsp %x %x %x %x err %d\n",
                                cmd->opcode, cmd->arg, cmd->flags,
                                cmd->resp[0], cmd->resp[1], cmd->resp[2],
                                cmd->resp[3], cmd->error);
                if (data)
                        seq_printf(s, "DATA %u / %u * %u flg %x err %d\n",
                                data->bytes_xfered, data->blocks,
                                data->blksz, data->flags, data->error);
                if (stop)
                        seq_printf(s,
                                "CMD%u(0x%x) flg %x rsp %x %x %x %x err %d\n",
                                stop->opcode, stop->arg, stop->flags,
                                stop->resp[0], stop->resp[1], stop->resp[2],
                                stop->resp[3], stop->error);
        }

        spin_unlock_bh(&slot->host->lock);

        return 0;
}

static int atmci_req_open(struct inode *inode, struct file *file)
{
        return single_open(file, atmci_req_show, inode->i_private);
}

static const struct file_operations atmci_req_fops = {
        .owner          = THIS_MODULE,
        .open           = atmci_req_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static void atmci_show_status_reg(struct seq_file *s,
                const char *regname, u32 value)
{
        static const char       *sr_bit[] = {
                [0]     = "CMDRDY",
                [1]     = "RXRDY",
                [2]     = "TXRDY",
                [3]     = "BLKE",
                [4]     = "DTIP",
                [5]     = "NOTBUSY",
                [6]     = "ENDRX",
                [7]     = "ENDTX",
                [8]     = "SDIOIRQA",
                [9]     = "SDIOIRQB",
                [12]    = "SDIOWAIT",
                [14]    = "RXBUFF",
                [15]    = "TXBUFE",
                [16]    = "RINDE",
                [17]    = "RDIRE",
                [18]    = "RCRCE",
                [19]    = "RENDE",
                [20]    = "RTOE",
                [21]    = "DCRCE",
                [22]    = "DTOE",
                [23]    = "CSTOE",
                [24]    = "BLKOVRE",
                [25]    = "DMADONE",
                [26]    = "FIFOEMPTY",
                [27]    = "XFRDONE",
                [30]    = "OVRE",
                [31]    = "UNRE",
        };
        unsigned int            i;

        seq_printf(s, "%s:\t0x%08x", regname, value);
        for (i = 0; i < ARRAY_SIZE(sr_bit); i++) {
                if (value & (1 << i)) {
                        if (sr_bit[i])
                                seq_printf(s, " %s", sr_bit[i]);
                        else
                                seq_puts(s, " UNKNOWN");
                }
        }
        seq_putc(s, '\n');
}

static int atmci_regs_show(struct seq_file *s, void *v)
{
        struct atmel_mci        *host = s->private;
        u32                     *buf;

        buf = kmalloc(ATMCI_REGS_SIZE, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        /*
         * Grab a more or less consistent snapshot. Note that we're
         * not disabling interrupts, so IMR and SR may not be
         * consistent.
         */
        spin_lock_bh(&host->lock);
        clk_enable(host->mck);
        memcpy_fromio(buf, host->regs, ATMCI_REGS_SIZE);
        clk_disable(host->mck);
        spin_unlock_bh(&host->lock);

        seq_printf(s, "MR:\t0x%08x%s%s ",
                        buf[ATMCI_MR / 4],
                        buf[ATMCI_MR / 4] & ATMCI_MR_RDPROOF ? " RDPROOF" : "",
                        buf[ATMCI_MR / 4] & ATMCI_MR_WRPROOF ? " WRPROOF" : "");
        if (host->caps.has_odd_clk_div)
                seq_printf(s, "{CLKDIV,CLKODD}=%u\n",
                                ((buf[ATMCI_MR / 4] & 0xff) << 1)
                                | ((buf[ATMCI_MR / 4] >> 16) & 1));
        else
                seq_printf(s, "CLKDIV=%u\n",
                                (buf[ATMCI_MR / 4] & 0xff));
        seq_printf(s, "DTOR:\t0x%08x\n", buf[ATMCI_DTOR / 4]);
        seq_printf(s, "SDCR:\t0x%08x\n", buf[ATMCI_SDCR / 4]);
        seq_printf(s, "ARGR:\t0x%08x\n", buf[ATMCI_ARGR / 4]);
        seq_printf(s, "BLKR:\t0x%08x BCNT=%u BLKLEN=%u\n",
                        buf[ATMCI_BLKR / 4],
                        buf[ATMCI_BLKR / 4] & 0xffff,
                        (buf[ATMCI_BLKR / 4] >> 16) & 0xffff);
        if (host->caps.has_cstor_reg)
                seq_printf(s, "CSTOR:\t0x%08x\n", buf[ATMCI_CSTOR / 4]);

        /* Don't read RSPR and RDR; it will consume the data there */

        atmci_show_status_reg(s, "SR", buf[ATMCI_SR / 4]);
        atmci_show_status_reg(s, "IMR", buf[ATMCI_IMR / 4]);

        if (host->caps.has_dma_conf_reg) {
                u32 val;

                val = buf[ATMCI_DMA / 4];
                seq_printf(s, "DMA:\t0x%08x OFFSET=%u CHKSIZE=%u%s\n",
                                val, val & 3,
                                ((val >> 4) & 3) ?
                                        1 << (((val >> 4) & 3) + 1) : 1,
                                val & ATMCI_DMAEN ? " DMAEN" : "");
        }
        if (host->caps.has_cfg_reg) {
                u32 val;

                val = buf[ATMCI_CFG / 4];
                seq_printf(s, "CFG:\t0x%08x%s%s%s%s\n",
                                val,
                                val & ATMCI_CFG_FIFOMODE_1DATA ? " FIFOMODE_ONE_DATA" : "",
                                val & ATMCI_CFG_FERRCTRL_COR ? " FERRCTRL_CLEAR_ON_READ" : "",
                                val & ATMCI_CFG_HSMODE ? " HSMODE" : "",
                                val & ATMCI_CFG_LSYNC ? " LSYNC" : "");
        }

        kfree(buf);

        return 0;
}

static int atmci_regs_open(struct inode *inode, struct file *file)
{
        return single_open(file, atmci_regs_show, inode->i_private);
}

static const struct file_operations atmci_regs_fops = {
        .owner          = THIS_MODULE,
        .open           = atmci_regs_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static void atmci_init_debugfs(struct atmel_mci_slot *slot)
{
        struct mmc_host         *mmc = slot->mmc;
        struct atmel_mci        *host = slot->host;
        struct dentry           *root;
        struct dentry           *node;

        root = mmc->debugfs_root;
        if (!root)
                return;

        node = debugfs_create_file("regs", S_IRUSR, root, host,
                        &atmci_regs_fops);
        if (IS_ERR(node))
                return;
        if (!node)
                goto err;

        node = debugfs_create_file("req", S_IRUSR, root, slot, &atmci_req_fops);
        if (!node)
                goto err;

        node = debugfs_create_u32("state", S_IRUSR, root, (u32 *)&host->state);
        if (!node)
                goto err;

        node = debugfs_create_x32("pending_events", S_IRUSR, root,
                                     (u32 *)&host->pending_events);
        if (!node)
                goto err;

        node = debugfs_create_x32("completed_events", S_IRUSR, root,
                                     (u32 *)&host->completed_events);
        if (!node)
                goto err;

        return;

err:
        dev_err(&mmc->class_dev, "failed to initialize debugfs for slot\n");
}

#if defined(CONFIG_OF)
static const struct of_device_id atmci_dt_ids[] = {
        { .compatible = "atmel,hsmci" },
        { /* sentinel */ }
};

MODULE_DEVICE_TABLE(of, atmci_dt_ids);

static struct mci_platform_data*
atmci_of_init(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct device_node *cnp;
        struct mci_platform_data *pdata;
        u32 slot_id;

        if (!np) {
                dev_err(&pdev->dev, "device node not found\n");
                return ERR_PTR(-EINVAL);
        }

        pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
        if (!pdata) {
                dev_err(&pdev->dev, "could not allocate memory for pdata\n");
                return ERR_PTR(-ENOMEM);
        }

        for_each_child_of_node(np, cnp) {
                if (of_property_read_u32(cnp, "reg", &slot_id)) {
                        dev_warn(&pdev->dev, "reg property is missing for %s\n",
                                 cnp->full_name);
                        continue;
                }

                if (slot_id >= ATMCI_MAX_NR_SLOTS) {
                        dev_warn(&pdev->dev, "can't have more than %d slots\n",
                                 ATMCI_MAX_NR_SLOTS);
                        break;
                }

                if (of_property_read_u32(cnp, "bus-width",
                                         &pdata->slot[slot_id].bus_width))
                        pdata->slot[slot_id].bus_width = 1;

                pdata->slot[slot_id].detect_pin =
                        of_get_named_gpio(cnp, "cd-gpios", 0);

                pdata->slot[slot_id].detect_is_active_high =
                        of_property_read_bool(cnp, "cd-inverted");

                pdata->slot[slot_id].wp_pin =
                        of_get_named_gpio(cnp, "wp-gpios", 0);
        }

        return pdata;
}
#else /* CONFIG_OF */
static inline struct mci_platform_data*
atmci_of_init(struct platform_device *dev)
{
        return ERR_PTR(-EINVAL);
}
#endif

static inline unsigned int atmci_get_version(struct atmel_mci *host)
{
        return atmci_readl(host, ATMCI_VERSION) & 0x00000fff;
}

static void atmci_timeout_timer(unsigned long data)
{
        struct atmel_mci *host;

        host = (struct atmel_mci *)data;

        dev_dbg(&host->pdev->dev, "software timeout\n");

        if (host->mrq->cmd->data) {
                host->mrq->cmd->data->error = -ETIMEDOUT;
                host->data = NULL;
        } else {
                host->mrq->cmd->error = -ETIMEDOUT;
                host->cmd = NULL;
        }
        host->need_reset = 1;
        host->state = STATE_END_REQUEST;
        smp_wmb();
        tasklet_schedule(&host->tasklet);
}

static inline unsigned int atmci_ns_to_clocks(struct atmel_mci *host,
                                        unsigned int ns)
{
        /*
         * It is easier here to use us instead of ns for the timeout,
         * it prevents from overflows during calculation.
         */
        unsigned int us = DIV_ROUND_UP(ns, 1000);

        /* Maximum clock frequency is host->bus_hz/2 */
        return us * (DIV_ROUND_UP(host->bus_hz, 2000000));
}

static void atmci_set_timeout(struct atmel_mci *host,
                struct atmel_mci_slot *slot, struct mmc_data *data)
{
        static unsigned dtomul_to_shift[] = {
                0, 4, 7, 8, 10, 12, 16, 20
        };
        unsigned        timeout;
        unsigned        dtocyc;
        unsigned        dtomul;

        timeout = atmci_ns_to_clocks(host, data->timeout_ns)
                + data->timeout_clks;

        for (dtomul = 0; dtomul < 8; dtomul++) {
                unsigned shift = dtomul_to_shift[dtomul];
                dtocyc = (timeout + (1 << shift) - 1) >> shift;
                if (dtocyc < 15)
                        break;
        }

        if (dtomul >= 8) {
                dtomul = 7;
                dtocyc = 15;
        }

        dev_vdbg(&slot->mmc->class_dev, "setting timeout to %u cycles\n",
                        dtocyc << dtomul_to_shift[dtomul]);
        atmci_writel(host, ATMCI_DTOR, (ATMCI_DTOMUL(dtomul) | ATMCI_DTOCYC(dtocyc)));
}

/*
 * Return mask with command flags to be enabled for this command.
 */
static u32 atmci_prepare_command(struct mmc_host *mmc,
                                 struct mmc_command *cmd)
{
        struct mmc_data *data;
        u32             cmdr;

        cmd->error = -EINPROGRESS;

        cmdr = ATMCI_CMDR_CMDNB(cmd->opcode);

        if (cmd->flags & MMC_RSP_PRESENT) {
                if (cmd->flags & MMC_RSP_136)
                        cmdr |= ATMCI_CMDR_RSPTYP_136BIT;
                else
                        cmdr |= ATMCI_CMDR_RSPTYP_48BIT;
        }

        /*
         * This should really be MAXLAT_5 for CMD2 and ACMD41, but
         * it's too difficult to determine whether this is an ACMD or
         * not. Better make it 64.
         */
        cmdr |= ATMCI_CMDR_MAXLAT_64CYC;

        if (mmc->ios.bus_mode == MMC_BUSMODE_OPENDRAIN)
                cmdr |= ATMCI_CMDR_OPDCMD;

        data = cmd->data;
        if (data) {
                cmdr |= ATMCI_CMDR_START_XFER;

                if (cmd->opcode == SD_IO_RW_EXTENDED) {
                        cmdr |= ATMCI_CMDR_SDIO_BLOCK;
                } else {
                        if (data->flags & MMC_DATA_STREAM)
                                cmdr |= ATMCI_CMDR_STREAM;
                        else if (data->blocks > 1)
                                cmdr |= ATMCI_CMDR_MULTI_BLOCK;
                        else
                                cmdr |= ATMCI_CMDR_BLOCK;
                }

                if (data->flags & MMC_DATA_READ)
                        cmdr |= ATMCI_CMDR_TRDIR_READ;
        }

        return cmdr;
}

static void atmci_send_command(struct atmel_mci *host,
                struct mmc_command *cmd, u32 cmd_flags)
{
        WARN_ON(host->cmd);
        host->cmd = cmd;

        dev_vdbg(&host->pdev->dev,
                        "start command: ARGR=0x%08x CMDR=0x%08x\n",
                        cmd->arg, cmd_flags);

        atmci_writel(host, ATMCI_ARGR, cmd->arg);
        atmci_writel(host, ATMCI_CMDR, cmd_flags);
}

static void atmci_send_stop_cmd(struct atmel_mci *host, struct mmc_data *data)
{
        dev_dbg(&host->pdev->dev, "send stop command\n");
        atmci_send_command(host, data->stop, host->stop_cmdr);
        atmci_writel(host, ATMCI_IER, ATMCI_CMDRDY);
}

/*
 * Configure given PDC buffer taking care of alignement issues.
 * Update host->data_size and host->sg.
 */
static void atmci_pdc_set_single_buf(struct atmel_mci *host,
        enum atmci_xfer_dir dir, enum atmci_pdc_buf buf_nb)
{
        u32 pointer_reg, counter_reg;
        unsigned int buf_size;

        if (dir == XFER_RECEIVE) {
                pointer_reg = ATMEL_PDC_RPR;
                counter_reg = ATMEL_PDC_RCR;
        } else {
                pointer_reg = ATMEL_PDC_TPR;
                counter_reg = ATMEL_PDC_TCR;
        }

        if (buf_nb == PDC_SECOND_BUF) {
                pointer_reg += ATMEL_PDC_SCND_BUF_OFF;
                counter_reg += ATMEL_PDC_SCND_BUF_OFF;
        }

        if (!host->caps.has_rwproof) {
                buf_size = host->buf_size;
                atmci_writel(host, pointer_reg, host->buf_phys_addr);
        } else {
                buf_size = sg_dma_len(host->sg);
                atmci_writel(host, pointer_reg, sg_dma_address(host->sg));
        }

        if (host->data_size <= buf_size) {
                if (host->data_size & 0x3) {
                        /* If size is different from modulo 4, transfer bytes */
                        atmci_writel(host, counter_reg, host->data_size);
                        atmci_writel(host, ATMCI_MR, host->mode_reg | ATMCI_MR_PDCFBYTE);
                } else {
                        /* Else transfer 32-bits words */
                        atmci_writel(host, counter_reg, host->data_size / 4);
                }
                host->data_size = 0;
        } else {
                /* We assume the size of a page is 32-bits aligned */
                atmci_writel(host, counter_reg, sg_dma_len(host->sg) / 4);
                host->data_size -= sg_dma_len(host->sg);
                if (host->data_size)
                        host->sg = sg_next(host->sg);
        }
}

/*
 * Configure PDC buffer according to the data size ie configuring one or two
 * buffers. Don't use this function if you want to configure only the second
 * buffer. In this case, use atmci_pdc_set_single_buf.
 */
static void atmci_pdc_set_both_buf(struct atmel_mci *host, int dir)
{
        atmci_pdc_set_single_buf(host, dir, PDC_FIRST_BUF);
        if (host->data_size)
                atmci_pdc_set_single_buf(host, dir, PDC_SECOND_BUF);
}

/*
 * Unmap sg lists, called when transfer is finished.
 */
static void atmci_pdc_cleanup(struct atmel_mci *host)
{
        struct mmc_data         *data = host->data;

        if (data)
                dma_unmap_sg(&host->pdev->dev,
                                data->sg, data->sg_len,
                                ((data->flags & MMC_DATA_WRITE)
                                 ? DMA_TO_DEVICE : DMA_FROM_DEVICE));
}

/*
 * Disable PDC transfers. Update pending flags to EVENT_XFER_COMPLETE after
 * having received ATMCI_TXBUFE or ATMCI_RXBUFF interrupt. Enable ATMCI_NOTBUSY
 * interrupt needed for both transfer directions.
 */
static void atmci_pdc_complete(struct atmel_mci *host)
{
        int transfer_size = host->data->blocks * host->data->blksz;
        int i;

        atmci_writel(host, ATMEL_PDC_PTCR, ATMEL_PDC_RXTDIS | ATMEL_PDC_TXTDIS);

        if ((!host->caps.has_rwproof)
            && (host->data->flags & MMC_DATA_READ)) {
                if (host->caps.has_bad_data_ordering)
                        for (i = 0; i < transfer_size; i++)
                                host->buffer[i] = swab32(host->buffer[i]);
                sg_copy_from_buffer(host->data->sg, host->data->sg_len,
                                    host->buffer, transfer_size);
        }

        atmci_pdc_cleanup(host);

        /*
         * If the card was removed, data will be NULL. No point trying
         * to send the stop command or waiting for NBUSY in this case.
         */
        if (host->data) {
                dev_dbg(&host->pdev->dev,
                        "(%s) set pending xfer complete\n", __func__);
                atmci_set_pending(host, EVENT_XFER_COMPLETE);
                tasklet_schedule(&host->tasklet);
        }
}

static void atmci_dma_cleanup(struct atmel_mci *host)
{
        struct mmc_data                 *data = host->data;

        if (data)
                dma_unmap_sg(host->dma.chan->device->dev,
                                data->sg, data->sg_len,
                                ((data->flags & MMC_DATA_WRITE)
                                 ? DMA_TO_DEVICE : DMA_FROM_DEVICE));
}

/*
 * This function is called by the DMA driver from tasklet context.
 */
static void atmci_dma_complete(void *arg)
{
        struct atmel_mci        *host = arg;
        struct mmc_data         *data = host->data;

        dev_vdbg(&host->pdev->dev, "DMA complete\n");

        if (host->caps.has_dma_conf_reg)
                /* Disable DMA hardware handshaking on MCI */
                atmci_writel(host, ATMCI_DMA, atmci_readl(host, ATMCI_DMA) & ~ATMCI_DMAEN);

        atmci_dma_cleanup(host);

        /*
         * If the card was removed, data will be NULL. No point trying
         * to send the stop command or waiting for NBUSY in this case.
         */
        if (data) {
                dev_dbg(&host->pdev->dev,
                        "(%s) set pending xfer complete\n", __func__);
                atmci_set_pending(host, EVENT_XFER_COMPLETE);
                tasklet_schedule(&host->tasklet);

                /*
                 * Regardless of what the documentation says, we have
                 * to wait for NOTBUSY even after block read
                 * operations.
                 *
                 * When the DMA transfer is complete, the controller
                 * may still be reading the CRC from the card, i.e.
                 * the data transfer is still in progress and we
                 * haven't seen all the potential error bits yet.
                 *
                 * The interrupt handler will schedule a different
                 * tasklet to finish things up when the data transfer
                 * is completely done.
                 *
                 * We may not complete the mmc request here anyway
                 * because the mmc layer may call back and cause us to
                 * violate the "don't submit new operations from the
                 * completion callback" rule of the dma engine
                 * framework.
                 */
                atmci_writel(host, ATMCI_IER, ATMCI_NOTBUSY);
        }
}

/*
 * Returns a mask of interrupt flags to be enabled after the whole
 * request has been prepared.
 */
static u32 atmci_prepare_data(struct atmel_mci *host, struct mmc_data *data)
{
        u32 iflags;

        data->error = -EINPROGRESS;

        host->sg = data->sg;
        host->sg_len = data->sg_len;
        host->data = data;
        host->data_chan = NULL;

        iflags = ATMCI_DATA_ERROR_FLAGS;

        /*
         * Errata: MMC data write operation with less than 12
         * bytes is impossible.
         *
         * Errata: MCI Transmit Data Register (TDR) FIFO
         * corruption when length is not multiple of 4.
         */
        if (data->blocks * data->blksz < 12
                        || (data->blocks * data->blksz) & 3)
                host->need_reset = true;

        host->pio_offset = 0;
        if (data->flags & MMC_DATA_READ)
                iflags |= ATMCI_RXRDY;
        else
                iflags |= ATMCI_TXRDY;

        return iflags;
}

/*
 * Set interrupt flags and set block length into the MCI mode register even
 * if this value is also accessible in the MCI block register. It seems to be
 * necessary before the High Speed MCI version. It also map sg and configure
 * PDC registers.
 */
static u32
atmci_prepare_data_pdc(struct atmel_mci *host, struct mmc_data *data)
{
        u32 iflags, tmp;
        unsigned int sg_len;
        enum dma_data_direction dir;
        int i;

        data->error = -EINPROGRESS;

        host->data = data;
        host->sg = data->sg;
        iflags = ATMCI_DATA_ERROR_FLAGS;

        /* Enable pdc mode */
        atmci_writel(host, ATMCI_MR, host->mode_reg | ATMCI_MR_PDCMODE);

        if (data->flags & MMC_DATA_READ) {
                dir = DMA_FROM_DEVICE;
                iflags |= ATMCI_ENDRX | ATMCI_RXBUFF;
        } else {
                dir = DMA_TO_DEVICE;
                iflags |= ATMCI_ENDTX | ATMCI_TXBUFE | ATMCI_BLKE;
        }

        /* Set BLKLEN */
        tmp = atmci_readl(host, ATMCI_MR);
        tmp &= 0x0000ffff;
        tmp |= ATMCI_BLKLEN(data->blksz);
        atmci_writel(host, ATMCI_MR, tmp);

        /* Configure PDC */
        host->data_size = data->blocks * data->blksz;
        sg_len = dma_map_sg(&host->pdev->dev, data->sg, data->sg_len, dir);

        if ((!host->caps.has_rwproof)
            && (host->data->flags & MMC_DATA_WRITE)) {
                sg_copy_to_buffer(host->data->sg, host->data->sg_len,
                                  host->buffer, host->data_size);
                if (host->caps.has_bad_data_ordering)
                        for (i = 0; i < host->data_size; i++)
                                host->buffer[i] = swab32(host->buffer[i]);
        }

        if (host->data_size)
                atmci_pdc_set_both_buf(host,
                        ((dir == DMA_FROM_DEVICE) ? XFER_RECEIVE : XFER_TRANSMIT));

        return iflags;
}

static u32
atmci_prepare_data_dma(struct atmel_mci *host, struct mmc_data *data)
{
        struct dma_chan                 *chan;
        struct dma_async_tx_descriptor  *desc;
        struct scatterlist              *sg;
        unsigned int                    i;
        enum dma_data_direction         direction;
        enum dma_transfer_direction     slave_dirn;
        unsigned int                    sglen;
        u32                             maxburst;
        u32 iflags;

        data->error = -EINPROGRESS;

        WARN_ON(host->data);
        host->sg = NULL;
        host->data = data;

        iflags = ATMCI_DATA_ERROR_FLAGS;

        /*
         * We don't do DMA on "complex" transfers, i.e. with
         * non-word-aligned buffers or lengths. Also, we don't bother

         * with all the DMA setup overhead for short transfers.
         */
        if (data->blocks * data->blksz < ATMCI_DMA_THRESHOLD)
                return atmci_prepare_data(host, data);
        if (data->blksz & 3)
                return atmci_prepare_data(host, data);

        for_each_sg(data->sg, sg, data->sg_len, i) {
                if (sg->offset & 3 || sg->length & 3)
                        return atmci_prepare_data(host, data);
        }

        /* If we don't have a channel, we can't do DMA */
        chan = host->dma.chan;
        if (chan)
                host->data_chan = chan;

        if (!chan)
                return -ENODEV;

        if (data->flags & MMC_DATA_READ) {
                direction = DMA_FROM_DEVICE;
                host->dma_conf.direction = slave_dirn = DMA_DEV_TO_MEM;
                maxburst = atmci_convert_chksize(host->dma_conf.src_maxburst);
        } else {
                direction = DMA_TO_DEVICE;
                host->dma_conf.direction = slave_dirn = DMA_MEM_TO_DEV;
                maxburst = atmci_convert_chksize(host->dma_conf.dst_maxburst);
        }

        if (host->caps.has_dma_conf_reg)
                atmci_writel(host, ATMCI_DMA, ATMCI_DMA_CHKSIZE(maxburst) |
                        ATMCI_DMAEN);

        sglen = dma_map_sg(chan->device->dev, data->sg,
                        data->sg_len, direction);

        dmaengine_slave_config(chan, &host->dma_conf);
        desc = dmaengine_prep_slave_sg(chan,
                        data->sg, sglen, slave_dirn,
                        DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
        if (!desc)
                goto unmap_exit;

        host->dma.data_desc = desc;
        desc->callback = atmci_dma_complete;
        desc->callback_param = host;

        return iflags;
unmap_exit:
        dma_unmap_sg(chan->device->dev, data->sg, data->sg_len, direction);
        return -ENOMEM;
}

static void
atmci_submit_data(struct atmel_mci *host, struct mmc_data *data)
{
        return;
}

/*
 * Start PDC according to transfer direction.
 */
static void
atmci_submit_data_pdc(struct atmel_mci *host, struct mmc_data *data)
{
        if (data->flags & MMC_DATA_READ)
                atmci_writel(host, ATMEL_PDC_PTCR, ATMEL_PDC_RXTEN);
        else
                atmci_writel(host, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN);
}

static void
atmci_submit_data_dma(struct atmel_mci *host, struct mmc_data *data)
{
        struct dma_chan                 *chan = host->data_chan;
        struct dma_async_tx_descriptor  *desc = host->dma.data_desc;

        if (chan) {
                dmaengine_submit(desc);
                dma_async_issue_pending(chan);
        }
}

static void atmci_stop_transfer(struct atmel_mci *host)
{
        dev_dbg(&host->pdev->dev,
                "(%s) set pending xfer complete\n", __func__);
        atmci_set_pending(host, EVENT_XFER_COMPLETE);
        atmci_writel(host, ATMCI_IER, ATMCI_NOTBUSY);
}

/*
 * Stop data transfer because error(s) occurred.
 */
static void atmci_stop_transfer_pdc(struct atmel_mci *host)
{
        atmci_writel(host, ATMEL_PDC_PTCR, ATMEL_PDC_RXTDIS | ATMEL_PDC_TXTDIS);
}

static void atmci_stop_transfer_dma(struct atmel_mci *host)
{
        struct dma_chan *chan = host->data_chan;

        if (chan) {
                dmaengine_terminate_all(chan);
                atmci_dma_cleanup(host);
        } else {
                /* Data transfer was stopped by the interrupt handler */
                dev_dbg(&host->pdev->dev,
                        "(%s) set pending xfer complete\n", __func__);
                atmci_set_pending(host, EVENT_XFER_COMPLETE);
                atmci_writel(host, ATMCI_IER, ATMCI_NOTBUSY);
        }
}

/*
 * Start a request: prepare data if needed, prepare the command and activate
 * interrupts.
 */
static void atmci_start_request(struct atmel_mci *host,
                struct atmel_mci_slot *slot)
{
        struct mmc_request      *mrq;
        struct mmc_command      *cmd;
        struct mmc_data         *data;
        u32                     iflags;
        u32                     cmdflags;

        mrq = slot->mrq;
        host->cur_slot = slot;
        host->mrq = mrq;

        host->pending_events = 0;
        host->completed_events = 0;
        host->cmd_status = 0;
        host->data_status = 0;

        dev_dbg(&host->pdev->dev, "start request: cmd %u\n", mrq->cmd->opcode);

        if (host->need_reset || host->caps.need_reset_after_xfer) {
                iflags = atmci_readl(host, ATMCI_IMR);
                iflags &= (ATMCI_SDIOIRQA | ATMCI_SDIOIRQB);
                atmci_writel(host, ATMCI_CR, ATMCI_CR_SWRST);
                atmci_writel(host, ATMCI_CR, ATMCI_CR_MCIEN);
                atmci_writel(host, ATMCI_MR, host->mode_reg);
                if (host->caps.has_cfg_reg)
                        atmci_writel(host, ATMCI_CFG, host->cfg_reg);
                atmci_writel(host, ATMCI_IER, iflags);
                host->need_reset = false;
        }
        atmci_writel(host, ATMCI_SDCR, slot->sdc_reg);

        iflags = atmci_readl(host, ATMCI_IMR);
        if (iflags & ~(ATMCI_SDIOIRQA | ATMCI_SDIOIRQB))
                dev_dbg(&slot->mmc->class_dev, "WARNING: IMR=0x%08x\n",
                                iflags);

        if (unlikely(test_and_clear_bit(ATMCI_CARD_NEED_INIT, &slot->flags))) {
                /* Send init sequence (74 clock cycles) */
                atmci_writel(host, ATMCI_CMDR, ATMCI_CMDR_SPCMD_INIT);
                while (!(atmci_readl(host, ATMCI_SR) & ATMCI_CMDRDY))
                        cpu_relax();
        }
        iflags = 0;
        data = mrq->data;
        if (data) {
                atmci_set_timeout(host, slot, data);

                /* Must set block count/size before sending command */
                atmci_writel(host, ATMCI_BLKR, ATMCI_BCNT(data->blocks)
                                | ATMCI_BLKLEN(data->blksz));
                dev_vdbg(&slot->mmc->class_dev, "BLKR=0x%08x\n",
                        ATMCI_BCNT(data->blocks) | ATMCI_BLKLEN(data->blksz));

                iflags |= host->prepare_data(host, data);
        }

        iflags |= ATMCI_CMDRDY;
        cmd = mrq->cmd;
        cmdflags = atmci_prepare_command(slot->mmc, cmd);
        atmci_send_command(host, cmd, cmdflags);

        if (data)
                host->submit_data(host, data);

        if (mrq->stop) {
                host->stop_cmdr = atmci_prepare_command(slot->mmc, mrq->stop);
                host->stop_cmdr |= ATMCI_CMDR_STOP_XFER;
                if (!(data->flags & MMC_DATA_WRITE))
                        host->stop_cmdr |= ATMCI_CMDR_TRDIR_READ;
                if (data->flags & MMC_DATA_STREAM)
                        host->stop_cmdr |= ATMCI_CMDR_STREAM;
                else
                        host->stop_cmdr |= ATMCI_CMDR_MULTI_BLOCK;
        }

        /*
         * We could have enabled interrupts earlier, but I suspect
         * that would open up a nice can of interesting race
         * conditions (e.g. command and data complete, but stop not
         * prepared yet.)
         */
        atmci_writel(host, ATMCI_IER, iflags);

        mod_timer(&host->timer, jiffies +  msecs_to_jiffies(2000));
}

static void atmci_queue_request(struct atmel_mci *host,
                struct atmel_mci_slot *slot, struct mmc_request *mrq)
{
        dev_vdbg(&slot->mmc->class_dev, "queue request: state=%d\n",
                        host->state);

        spin_lock_bh(&host->lock);
        slot->mrq = mrq;
        if (host->state == STATE_IDLE) {
                host->state = STATE_SENDING_CMD;
                atmci_start_request(host, slot);
        } else {
                dev_dbg(&host->pdev->dev, "queue request\n");
                list_add_tail(&slot->queue_node, &host->queue);
        }
        spin_unlock_bh(&host->lock);
}

static void atmci_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
        struct atmel_mci_slot   *slot = mmc_priv(mmc);
        struct atmel_mci        *host = slot->host;
        struct mmc_data         *data;

        WARN_ON(slot->mrq);
        dev_dbg(&host->pdev->dev, "MRQ: cmd %u\n", mrq->cmd->opcode);

        /*
         * We may "know" the card is gone even though there's still an
         * electrical connection. If so, we really need to communicate
         * this to the MMC core since there won't be any more
         * interrupts as the card is completely removed. Otherwise,
         * the MMC core might believe the card is still there even
         * though the card was just removed very slowly.
         */
        if (!test_bit(ATMCI_CARD_PRESENT, &slot->flags)) {
                mrq->cmd->error = -ENOMEDIUM;
                mmc_request_done(mmc, mrq);
                return;
        }

        /* We don't support multiple blocks of weird lengths. */
        data = mrq->data;
        if (data && data->blocks > 1 && data->blksz & 3) {
                mrq->cmd->error = -EINVAL;
                mmc_request_done(mmc, mrq);
        }

        atmci_queue_request(host, slot, mrq);
}

static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
        struct atmel_mci_slot   *slot = mmc_priv(mmc);
        struct atmel_mci        *host = slot->host;
        unsigned int            i;

        slot->sdc_reg &= ~ATMCI_SDCBUS_MASK;
        switch (ios->bus_width) {
        case MMC_BUS_WIDTH_1:
                slot->sdc_reg |= ATMCI_SDCBUS_1BIT;
                break;
        case MMC_BUS_WIDTH_4:
                slot->sdc_reg |= ATMCI_SDCBUS_4BIT;
                break;
        }

        if (ios->clock) {
                unsigned int clock_min = ~0U;
                u32 clkdiv;

                spin_lock_bh(&host->lock);
                if (!host->mode_reg) {
                        clk_enable(host->mck);
                        atmci_writel(host, ATMCI_CR, ATMCI_CR_SWRST);
                        atmci_writel(host, ATMCI_CR, ATMCI_CR_MCIEN);
                        if (host->caps.has_cfg_reg)
                                atmci_writel(host, ATMCI_CFG, host->cfg_reg);
                }

                /*
                 * Use mirror of ios->clock to prevent race with mmc
                 * core ios update when finding the minimum.
                 */
                slot->clock = ios->clock;
                for (i = 0; i < ATMCI_MAX_NR_SLOTS; i++) {
                        if (host->slot[i] && host->slot[i]->clock
                                        && host->slot[i]->clock < clock_min)
                                clock_min = host->slot[i]->clock;
                }

                /* Calculate clock divider */
                if (host->caps.has_odd_clk_div) {
                        clkdiv = DIV_ROUND_UP(host->bus_hz, clock_min) - 2;
                        if (clkdiv > 511) {
                                dev_warn(&mmc->class_dev,
                                         "clock %u too slow; using %lu\n",
                                         clock_min, host->bus_hz / (511 + 2));
                                clkdiv = 511;
                        }
                        host->mode_reg = ATMCI_MR_CLKDIV(clkdiv >> 1)
                                         | ATMCI_MR_CLKODD(clkdiv & 1);
                } else {
                        clkdiv = DIV_ROUND_UP(host->bus_hz, 2 * clock_min) - 1;
                        if (clkdiv > 255) {
                                dev_warn(&mmc->class_dev,
                                         "clock %u too slow; using %lu\n",
                                         clock_min, host->bus_hz / (2 * 256));
                                clkdiv = 255;
                        }
                        host->mode_reg = ATMCI_MR_CLKDIV(clkdiv);
                }

                /*
                 * WRPROOF and RDPROOF prevent overruns/underruns by
                 * stopping the clock when the FIFO is full/empty.
                 * This state is not expected to last for long.
                 */
                if (host->caps.has_rwproof)
                        host->mode_reg |= (ATMCI_MR_WRPROOF | ATMCI_MR_RDPROOF);

                if (host->caps.has_cfg_reg) {
                        /* setup High Speed mode in relation with card capacity */
                        if (ios->timing == MMC_TIMING_SD_HS)
                                host->cfg_reg |= ATMCI_CFG_HSMODE;
                        else
                                host->cfg_reg &= ~ATMCI_CFG_HSMODE;
                }

                if (list_empty(&host->queue)) {
                        atmci_writel(host, ATMCI_MR, host->mode_reg);
                        if (host->caps.has_cfg_reg)
                                atmci_writel(host, ATMCI_CFG, host->cfg_reg);
                } else {
                        host->need_clock_update = true;
                }

                spin_unlock_bh(&host->lock);
        } else {
                bool any_slot_active = false;

                spin_lock_bh(&host->lock);
                slot->clock = 0;
                for (i = 0; i < ATMCI_MAX_NR_SLOTS; i++) {
                        if (host->slot[i] && host->slot[i]->clock) {
                                any_slot_active = true;
                                break;
                        }
                }
                if (!any_slot_active) {
                        atmci_writel(host, ATMCI_CR, ATMCI_CR_MCIDIS);
                        if (host->mode_reg) {
                                atmci_readl(host, ATMCI_MR);
                                clk_disable(host->mck);
                        }
                        host->mode_reg = 0;
                }
                spin_unlock_bh(&host->lock);
        }

        switch (ios->power_mode) {
        case MMC_POWER_UP:
                set_bit(ATMCI_CARD_NEED_INIT, &slot->flags);
                break;
        default:
                /*
                 * TODO: None of the currently available AVR32-based
                 * boards allow MMC power to be turned off. Implement
                 * power control when this can be tested properly.
                 *
                 * We also need to hook this into the clock management
                 * somehow so that newly inserted cards aren't
                 * subjected to a fast clock before we have a chance
                 * to figure out what the maximum rate is. Currently,
                 * there's no way to avoid this, and there never will
                 * be for boards that don't support power control.
                 */
                break;
        }
}

static int atmci_get_ro(struct mmc_host *mmc)
{
        int                     read_only = -ENOSYS;
        struct atmel_mci_slot   *slot = mmc_priv(mmc);

        if (gpio_is_valid(slot->wp_pin)) {
                read_only = gpio_get_value(slot->wp_pin);
                dev_dbg(&mmc->class_dev, "card is %s\n",
                                read_only ? "read-only" : "read-write");
        }

        return read_only;
}

static int atmci_get_cd(struct mmc_host *mmc)
{
        int                     present = -ENOSYS;
        struct atmel_mci_slot   *slot = mmc_priv(mmc);

        if (gpio_is_valid(slot->detect_pin)) {
                present = !(gpio_get_value(slot->detect_pin) ^
                            slot->detect_is_active_high);
                dev_dbg(&mmc->class_dev, "card is %spresent\n",
                                present ? "" : "not ");
        }

        return present;
}

static void atmci_enable_sdio_irq(struct mmc_host *mmc, int enable)
{
        struct atmel_mci_slot   *slot = mmc_priv(mmc);
        struct atmel_mci        *host = slot->host;

        if (enable)
                atmci_writel(host, ATMCI_IER, slot->sdio_irq);
        else
                atmci_writel(host, ATMCI_IDR, slot->sdio_irq);
}

static const struct mmc_host_ops atmci_ops = {
        .request        = atmci_request,
        .set_ios        = atmci_set_ios,
        .get_ro         = atmci_get_ro,
        .get_cd         = atmci_get_cd,
        .enable_sdio_irq = atmci_enable_sdio_irq,
};

/* Called with host->lock held */
static void atmci_request_end(struct atmel_mci *host, struct mmc_request *mrq)
        __releases(&host->lock)
        __acquires(&host->lock)
{
        struct atmel_mci_slot   *slot = NULL;
        struct mmc_host         *prev_mmc = host->cur_slot->mmc;

        WARN_ON(host->cmd || host->data);

        /*
         * Update the MMC clock rate if necessary. This may be
         * necessary if set_ios() is called when a different slot is
         * busy transferring data.
         */
        if (host->need_clock_update) {
                atmci_writel(host, ATMCI_MR, host->mode_reg);
                if (host->caps.has_cfg_reg)
                        atmci_writel(host, ATMCI_CFG, host->cfg_reg);
        }

        host->cur_slot->mrq = NULL;
        host->mrq = NULL;
        if (!list_empty(&host->queue)) {
                slot = list_entry(host->queue.next,
                                struct atmel_mci_slot, queue_node);
                list_del(&slot->queue_node);
                dev_vdbg(&host->pdev->dev, "list not empty: %s is next\n",
                                mmc_hostname(slot->mmc));
                host->state = STATE_SENDING_CMD;
                atmci_start_request(host, slot);
        } else {
                dev_vdbg(&host->pdev->dev, "list empty\n");
                host->state = STATE_IDLE;
        }

        del_timer(&host->timer);

        spin_unlock(&host->lock);
        mmc_request_done(prev_mmc, mrq);
        spin_lock(&host->lock);
}

static void atmci_command_complete(struct atmel_mci *host,
                        struct mmc_command *cmd)
{
        u32             status = host->cmd_status;

        /* Read the response from the card (up to 16 bytes) */
        cmd->resp[0] = atmci_readl(host, ATMCI_RSPR);
        cmd->resp[1] = atmci_readl(host, ATMCI_RSPR);
        cmd->resp[2] = atmci_readl(host, ATMCI_RSPR);
        cmd->resp[3] = atmci_readl(host, ATMCI_RSPR);

        if (status & ATMCI_RTOE)
                cmd->error = -ETIMEDOUT;
        else if ((cmd->flags & MMC_RSP_CRC) && (status & ATMCI_RCRCE))
                cmd->error = -EILSEQ;
        else if (status & (ATMCI_RINDE | ATMCI_RDIRE | ATMCI_RENDE))
                cmd->error = -EIO;
        else if (host->mrq->data && (host->mrq->data->blksz & 3)) {
                if (host->caps.need_blksz_mul_4) {
                        cmd->error = -EINVAL;
                        host->need_reset = 1;
                }
        } else
                cmd->error = 0;
}

static void atmci_detect_change(unsigned long data)
{
        struct atmel_mci_slot   *slot = (struct atmel_mci_slot *)data;
        bool                    present;
        bool                    present_old;

        /*
         * atmci_cleanup_slot() sets the ATMCI_SHUTDOWN flag before
         * freeing the interrupt. We must not re-enable the interrupt
         * if it has been freed, and if we're shutting down, it
         * doesn't really matter whether the card is present or not.
         */
        smp_rmb();
        if (test_bit(ATMCI_SHUTDOWN, &slot->flags))
                return;

        enable_irq(gpio_to_irq(slot->detect_pin));
        present = !(gpio_get_value(slot->detect_pin) ^
                    slot->detect_is_active_high);
        present_old = test_bit(ATMCI_CARD_PRESENT, &slot->flags);

        dev_vdbg(&slot->mmc->class_dev, "detect change: %d (was %d)\n",
                        present, present_old);

        if (present != present_old) {
                struct atmel_mci        *host = slot->host;
                struct mmc_request      *mrq;

                dev_dbg(&slot->mmc->class_dev, "card %s\n",
                        present ? "inserted" : "removed");

                spin_lock(&host->lock);

                if (!present)
                        clear_bit(ATMCI_CARD_PRESENT, &slot->flags);
                else
                        set_bit(ATMCI_CARD_PRESENT, &slot->flags);

                /* Clean up queue if present */
                mrq = slot->mrq;
                if (mrq) {
                        if (mrq == host->mrq) {
                                /*
                                 * Reset controller to terminate any ongoing
                                 * commands or data transfers.
                                 */
                                atmci_writel(host, ATMCI_CR, ATMCI_CR_SWRST);
                                atmci_writel(host, ATMCI_CR, ATMCI_CR_MCIEN);
                                atmci_writel(host, ATMCI_MR, host->mode_reg);
                                if (host->caps.has_cfg_reg)
                                        atmci_writel(host, ATMCI_CFG, host->cfg_reg);

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

                                switch (host->state) {
                                case STATE_IDLE:
                                        break;
                                case STATE_SENDING_CMD:
                                        mrq->cmd->error = -ENOMEDIUM;
                                        if (mrq->data)
                                                host->stop_transfer(host);
                                        break;
                                case STATE_DATA_XFER:
                                        mrq->data->error = -ENOMEDIUM;
                                        host->stop_transfer(host);
                                        break;
                                case STATE_WAITING_NOTBUSY:
                                        mrq->data->error = -ENOMEDIUM;
                                        break;
                                case STATE_SENDING_STOP:
                                        mrq->stop->error = -ENOMEDIUM;
                                        break;
                                case STATE_END_REQUEST:
                                        break;
                                }

                                atmci_request_end(host, mrq);
                        } else {
                                list_del(&slot->queue_node);
                                mrq->cmd->error = -ENOMEDIUM;
                                if (mrq->data)
                                        mrq->data->error = -ENOMEDIUM;
                                if (mrq->stop)
                                        mrq->stop->error = -ENOMEDIUM;

                                spin_unlock(&host->lock);
                                mmc_request_done(slot->mmc, mrq);
                                spin_lock(&host->lock);
                        }
                }
                spin_unlock(&host->lock);

                mmc_detect_change(slot->mmc, 0);
        }
}

static void atmci_tasklet_func(unsigned long priv)
{
        struct atmel_mci        *host = (struct atmel_mci *)priv;
        struct mmc_request      *mrq = host->mrq;
        struct mmc_data         *data = host->data;
        enum atmel_mci_state    state = host->state;
        enum atmel_mci_state    prev_state;
        u32                     status;

        spin_lock(&host->lock);

        state = host->state;

        dev_vdbg(&host->pdev->dev,
                "tasklet: state %u pending/completed/mask %lx/%lx/%x\n",
                state, host->pending_events, host->completed_events,
                atmci_readl(host, ATMCI_IMR));

        do {
                prev_state = state;
                dev_dbg(&host->pdev->dev, "FSM: state=%d\n", state);

                switch (state) {
                case STATE_IDLE:
                        break;

                case STATE_SENDING_CMD:
                        /*
                         * Command has been sent, we are waiting for command
                         * ready. Then we have three next states possible:
                         * END_REQUEST by default, WAITING_NOTBUSY if it's a
                         * command needing it or DATA_XFER if there is data.
                         */
                        dev_dbg(&host->pdev->dev, "FSM: cmd ready?\n");
                        if (!atmci_test_and_clear_pending(host,
                                                EVENT_CMD_RDY))
                                break;

                        dev_dbg(&host->pdev->dev, "set completed cmd ready\n");
                        host->cmd = NULL;
                        atmci_set_completed(host, EVENT_CMD_RDY);
                        atmci_command_complete(host, mrq->cmd);
                        if (mrq->data) {
                                dev_dbg(&host->pdev->dev,
                                        "command with data transfer");
                                /*
                                 * If there is a command error don't start
                                 * data transfer.
                                 */
                                if (mrq->cmd->error) {
                                        host->stop_transfer(host);
                                        host->data = NULL;
                                        atmci_writel(host, ATMCI_IDR,
                                                     ATMCI_TXRDY | ATMCI_RXRDY
                                                     | ATMCI_DATA_ERROR_FLAGS);
                                        state = STATE_END_REQUEST;
                                } else
                                        state = STATE_DATA_XFER;
                        } else if ((!mrq->data) && (mrq->cmd->flags & MMC_RSP_BUSY)) {
                                dev_dbg(&host->pdev->dev,
                                        "command response need waiting notbusy");
                                atmci_writel(host, ATMCI_IER, ATMCI_NOTBUSY);
                                state = STATE_WAITING_NOTBUSY;
                        } else
                                state = STATE_END_REQUEST;

                        break;

                case STATE_DATA_XFER:
                        if (atmci_test_and_clear_pending(host,
                                                EVENT_DATA_ERROR)) {
                                dev_dbg(&host->pdev->dev, "set completed data error\n");
                                atmci_set_completed(host, EVENT_DATA_ERROR);
                                state = STATE_END_REQUEST;
                                break;
                        }

                        /*
                         * A data transfer is in progress. The event expected
                         * to move to the next state depends of data transfer
                         * type (PDC or DMA). Once transfer done we can move
                         * to the next step which is WAITING_NOTBUSY in write
                         * case and directly SENDING_STOP in read case.
                         */
                        dev_dbg(&host->pdev->dev, "FSM: xfer complete?\n");
                        if (!atmci_test_and_clear_pending(host,
                                                EVENT_XFER_COMPLETE))
                                break;

                        dev_dbg(&host->pdev->dev,
                                "(%s) set completed xfer complete\n",
                                __func__);
                        atmci_set_completed(host, EVENT_XFER_COMPLETE);

                        if (host->caps.need_notbusy_for_read_ops ||
                           (host->data->flags & MMC_DATA_WRITE)) {
                                atmci_writel(host, ATMCI_IER, ATMCI_NOTBUSY);
                                state = STATE_WAITING_NOTBUSY;
                        } else if (host->mrq->stop) {
                                atmci_writel(host, ATMCI_IER, ATMCI_CMDRDY);
                                atmci_send_stop_cmd(host, data);
                                state = STATE_SENDING_STOP;
                        } else {
                                host->data = NULL;
                                data->bytes_xfered = data->blocks * data->blksz;
                                data->error = 0;
                                state = STATE_END_REQUEST;
                        }
                        break;

                case STATE_WAITING_NOTBUSY:
                        /*
                         * We can be in the state for two reasons: a command
                         * requiring waiting not busy signal (stop command
                         * included) or a write operation. In the latest case,
                         * we need to send a stop command.
                         */
                        dev_dbg(&host->pdev->dev, "FSM: not busy?\n");
                        if (!atmci_test_and_clear_pending(host,
                                                EVENT_NOTBUSY))
                                break;

                        dev_dbg(&host->pdev->dev, "set completed not busy\n");
                        atmci_set_completed(host, EVENT_NOTBUSY);

                        if (host->data) {
                                /*
                                 * For some commands such as CMD53, even if
                                 * there is data transfer, there is no stop
                                 * command to send.
                                 */
                                if (host->mrq->stop) {
                                        atmci_writel(host, ATMCI_IER,
                                                     ATMCI_CMDRDY);
                                        atmci_send_stop_cmd(host, data);
                                        state = STATE_SENDING_STOP;
                                } else {
                                        host->data = NULL;
                                        data->bytes_xfered = data->blocks
                                                             * data->blksz;
                                        data->error = 0;
                                        state = STATE_END_REQUEST;
                                }
                        } else
                                state = STATE_END_REQUEST;
                        break;

                case STATE_SENDING_STOP:
                        /*
                         * In this state, it is important to set host->data to
                         * NULL (which is tested in the waiting notbusy state)
                         * in order to go to the end request state instead of
                         * sending stop again.
                         */
                        dev_dbg(&host->pdev->dev, "FSM: cmd ready?\n");
                        if (!atmci_test_and_clear_pending(host,
                                                EVENT_CMD_RDY))
                                break;

                        dev_dbg(&host->pdev->dev, "FSM: cmd ready\n");
                        host->cmd = NULL;
                        data->bytes_xfered = data->blocks * data->blksz;
                        data->error = 0;
                        atmci_command_complete(host, mrq->stop);
                        if (mrq->stop->error) {
                                host->stop_transfer(host);
                                atmci_writel(host, ATMCI_IDR,
                                             ATMCI_TXRDY | ATMCI_RXRDY
                                             | ATMCI_DATA_ERROR_FLAGS);
                                state = STATE_END_REQUEST;
                        } else {
                                atmci_writel(host, ATMCI_IER, ATMCI_NOTBUSY);
                                state = STATE_WAITING_NOTBUSY;
                        }
                        host->data = NULL;
                        break;

                case STATE_END_REQUEST:
                        atmci_writel(host, ATMCI_IDR, ATMCI_TXRDY | ATMCI_RXRDY
                                           | ATMCI_DATA_ERROR_FLAGS);
                        status = host->data_status;
                        if (unlikely(status)) {
                                host->stop_transfer(host);
                                host->data = NULL;
                                if (status & ATMCI_DTOE) {
                                        data->error = -ETIMEDOUT;
                                } else if (status & ATMCI_DCRCE) {
                                        data->error = -EILSEQ;
                                } else {
                                        data->error = -EIO;
                                }
                        }

                        atmci_request_end(host, host->mrq);
                        state = STATE_IDLE;
                        break;
                }
        } while (state != prev_state);

        host->state = state;

        spin_unlock(&host->lock);
}

static void atmci_read_data_pio(struct atmel_mci *host)
{
        struct scatterlist      *sg = host->sg;
        void                    *buf = sg_virt(sg);
        unsigned int            offset = host->pio_offset;
        struct mmc_data         *data = host->data;
        u32                     value;
        u32                     status;
        unsigned int            nbytes = 0;

        do {
                value = atmci_readl(host, ATMCI_RDR);
                if (likely(offset + 4 <= sg->length)) {
                        put_unaligned(value, (u32 *)(buf + offset));

                        offset += 4;
                        nbytes += 4;

                        if (offset == sg->length) {
                                flush_dcache_page(sg_page(sg));
                                host->sg = sg = sg_next(sg);
                                host->sg_len--;
                                if (!sg || !host->sg_len)
                                        goto done;

                                offset = 0;
                                buf = sg_virt(sg);
                        }
                } else {
                        unsigned int remaining = sg->length - offset;
                        memcpy(buf + offset, &value, remaining);
                        nbytes += remaining;

                        flush_dcache_page(sg_page(sg));
                        host->sg = sg = sg_next(sg);
                        host->sg_len--;
                        if (!sg || !host->sg_len)
                                goto done;

                        offset = 4 - remaining;
                        buf = sg_virt(sg);
                        memcpy(buf, (u8 *)&value + remaining, offset);
                        nbytes += offset;
                }

                status = atmci_readl(host, ATMCI_SR);
                if (status & ATMCI_DATA_ERROR_FLAGS) {
                        atmci_writel(host, ATMCI_IDR, (ATMCI_NOTBUSY | ATMCI_RXRDY
                                                | ATMCI_DATA_ERROR_FLAGS));
                        host->data_status = status;
                        data->bytes_xfered += nbytes;
                        return;
                }
        } while (status & ATMCI_RXRDY);

        host->pio_offset = offset;
        data->bytes_xfered += nbytes;

        return;

done:
        atmci_writel(host, ATMCI_IDR, ATMCI_RXRDY);
        atmci_writel(host, ATMCI_IER, ATMCI_NOTBUSY);
        data->bytes_xfered += nbytes;
        smp_wmb();
        atmci_set_pending(host, EVENT_XFER_COMPLETE);
}

static void atmci_write_data_pio(struct atmel_mci *host)
{
        struct scatterlist      *sg = host->sg;
        void                    *buf = sg_virt(sg);
        unsigned int            offset = host->pio_offset;
        struct mmc_data         *data = host->data;
        u32                     value;
        u32                     status;
        unsigned int            nbytes = 0;

        do {
                if (likely(offset + 4 <= sg->length)) {
                        value = get_unaligned((u32 *)(buf + offset));
                        atmci_writel(host, ATMCI_TDR, value);

                        offset += 4;
                        nbytes += 4;
                        if (offset == sg->length) {
                                host->sg = sg = sg_next(sg);
                                host->sg_len--;
                                if (!sg || !host->sg_len)
                                        goto done;

                                offset = 0;
                                buf = sg_virt(sg);
                        }
                } else {
                        unsigned int remaining = sg->length - offset;

                        value = 0;
                        memcpy(&value, buf + offset, remaining);
                        nbytes += remaining;

                        host->sg = sg = sg_next(sg);
                        host->sg_len--;
                        if (!sg || !host->sg_len) {
                                atmci_writel(host, ATMCI_TDR, value);
                                goto done;
                        }

                        offset = 4 - remaining;
                        buf = sg_virt(sg);
                        memcpy((u8 *)&value + remaining, buf, offset);
                        atmci_writel(host, ATMCI_TDR, value);
                        nbytes += offset;
                }

                status = atmci_readl(host, ATMCI_SR);
                if (status & ATMCI_DATA_ERROR_FLAGS) {
                        atmci_writel(host, ATMCI_IDR, (ATMCI_NOTBUSY | ATMCI_TXRDY
                                                | ATMCI_DATA_ERROR_FLAGS));
                        host->data_status = status;
                        data->bytes_xfered += nbytes;
                        return;
                }
        } while (status & ATMCI_TXRDY);

        host->pio_offset = offset;
        data->bytes_xfered += nbytes;

        return;

done:
        atmci_writel(host, ATMCI_IDR, ATMCI_TXRDY);
        atmci_writel(host, ATMCI_IER, ATMCI_NOTBUSY);
        data->bytes_xfered += nbytes;
        smp_wmb();
        atmci_set_pending(host, EVENT_XFER_COMPLETE);
}

static void atmci_sdio_interrupt(struct atmel_mci *host, u32 status)
{
        int     i;

        for (i = 0; i < ATMCI_MAX_NR_SLOTS; i++) {
                struct atmel_mci_slot *slot = host->slot[i];
                if (slot && (status & slot->sdio_irq)) {
                        mmc_signal_sdio_irq(slot->mmc);
                }
        }
}


static irqreturn_t atmci_interrupt(int irq, void *dev_id)
{
        struct atmel_mci        *host = dev_id;
        u32                     status, mask, pending;
        unsigned int            pass_count = 0;

        do {
                status = atmci_readl(host, ATMCI_SR);
                mask = atmci_readl(host, ATMCI_IMR);
                pending = status & mask;
                if (!pending)
                        break;

                if (pending & ATMCI_DATA_ERROR_FLAGS) {
                        dev_dbg(&host->pdev->dev, "IRQ: data error\n");
                        atmci_writel(host, ATMCI_IDR, ATMCI_DATA_ERROR_FLAGS
                                        | ATMCI_RXRDY | ATMCI_TXRDY
                                        | ATMCI_ENDRX | ATMCI_ENDTX
                                        | ATMCI_RXBUFF | ATMCI_TXBUFE);

                        host->data_status = status;
                        dev_dbg(&host->pdev->dev, "set pending data error\n");
                        smp_wmb();
                        atmci_set_pending(host, EVENT_DATA_ERROR);
                        tasklet_schedule(&host->tasklet);
                }

                if (pending & ATMCI_TXBUFE) {
                        dev_dbg(&host->pdev->dev, "IRQ: tx buffer empty\n");
                        atmci_writel(host, ATMCI_IDR, ATMCI_TXBUFE);
                        atmci_writel(host, ATMCI_IDR, ATMCI_ENDTX);
                        /*
                         * We can receive this interruption before having configured
                         * the second pdc buffer, so we need to reconfigure first and
                         * second buffers again
                         */
                        if (host->data_size) {
                                atmci_pdc_set_both_buf(host, XFER_TRANSMIT);
                                atmci_writel(host, ATMCI_IER, ATMCI_ENDTX);
                                atmci_writel(host, ATMCI_IER, ATMCI_TXBUFE);
                        } else {
                                atmci_pdc_complete(host);

                        }
                } else if (pending & ATMCI_ENDTX) {
                        dev_dbg(&host->pdev->dev, "IRQ: end of tx buffer\n");
                        atmci_writel(host, ATMCI_IDR, ATMCI_ENDTX);

                        if (host->data_size) {
                                atmci_pdc_set_single_buf(host,
                                                XFER_TRANSMIT, PDC_SECOND_BUF);
                                atmci_writel(host, ATMCI_IER, ATMCI_ENDTX);
                        }
                }

                if (pending & ATMCI_RXBUFF) {
                        dev_dbg(&host->pdev->dev, "IRQ: rx buffer full\n");
                        atmci_writel(host, ATMCI_IDR, ATMCI_RXBUFF);
                        atmci_writel(host, ATMCI_IDR, ATMCI_ENDRX);
                        /*
                         * We can receive this interruption before having configured
                         * the second pdc buffer, so we need to reconfigure first and
                         * second buffers again
                         */
                        if (host->data_size) {
                                atmci_pdc_set_both_buf(host, XFER_RECEIVE);
                                atmci_writel(host, ATMCI_IER, ATMCI_ENDRX);
                                atmci_writel(host, ATMCI_IER, ATMCI_RXBUFF);
                        } else {
                                atmci_pdc_complete(host);
                        }
                } else if (pending & ATMCI_ENDRX) {
                        dev_dbg(&host->pdev->dev, "IRQ: end of rx buffer\n");
                        atmci_writel(host, ATMCI_IDR, ATMCI_ENDRX);

                        if (host->data_size) {
                                atmci_pdc_set_single_buf(host,
                                                XFER_RECEIVE, PDC_SECOND_BUF);
                                atmci_writel(host, ATMCI_IER, ATMCI_ENDRX);
                        }
                }

                /*
                 * First mci IPs, so mainly the ones having pdc, have some
                 * issues with the notbusy signal. You can't get it after
                 * data transmission if you have not sent a stop command.
                 * The appropriate workaround is to use the BLKE signal.
                 */
                if (pending & ATMCI_BLKE) {
                        dev_dbg(&host->pdev->dev, "IRQ: blke\n");
                        atmci_writel(host, ATMCI_IDR, ATMCI_BLKE);
                        smp_wmb();
                        dev_dbg(&host->pdev->dev, "set pending notbusy\n");
                        atmci_set_pending(host, EVENT_NOTBUSY);
                        tasklet_schedule(&host->tasklet);
                }

                if (pending & ATMCI_NOTBUSY) {
                        dev_dbg(&host->pdev->dev, "IRQ: not_busy\n");
                        atmci_writel(host, ATMCI_IDR, ATMCI_NOTBUSY);
                        smp_wmb();
                        dev_dbg(&host->pdev->dev, "set pending notbusy\n");
                        atmci_set_pending(host, EVENT_NOTBUSY);
                        tasklet_schedule(&host->tasklet);
                }

                if (pending & ATMCI_RXRDY)
                        atmci_read_data_pio(host);
                if (pending & ATMCI_TXRDY)
                        atmci_write_data_pio(host);

                if (pending & ATMCI_CMDRDY) {
                        dev_dbg(&host->pdev->dev, "IRQ: cmd ready\n");
                        atmci_writel(host, ATMCI_IDR, ATMCI_CMDRDY);
                        host->cmd_status = status;
                        smp_wmb();
                        dev_dbg(&host->pdev->dev, "set pending cmd rdy\n");
                        atmci_set_pending(host, EVENT_CMD_RDY);
                        tasklet_schedule(&host->tasklet);
                }

                if (pending & (ATMCI_SDIOIRQA | ATMCI_SDIOIRQB))
                        atmci_sdio_interrupt(host, status);

        } while (pass_count++ < 5);

        return pass_count ? IRQ_HANDLED : IRQ_NONE;
}

static irqreturn_t atmci_detect_interrupt(int irq, void *dev_id)
{
        struct atmel_mci_slot   *slot = dev_id;

        /*
         * Disable interrupts until the pin has stabilized and check
         * the state then. Use mod_timer() since we may be in the
         * middle of the timer routine when this interrupt triggers.
         */
        disable_irq_nosync(irq);
        mod_timer(&slot->detect_timer, jiffies + msecs_to_jiffies(20));

        return IRQ_HANDLED;
}

static int __init atmci_init_slot(struct atmel_mci *host,
                struct mci_slot_pdata *slot_data, unsigned int id,
                u32 sdc_reg, u32 sdio_irq)
{
        struct mmc_host                 *mmc;
        struct atmel_mci_slot           *slot;

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

        slot = mmc_priv(mmc);
        slot->mmc = mmc;
        slot->host = host;
        slot->detect_pin = slot_data->detect_pin;
        slot->wp_pin = slot_data->wp_pin;
        slot->detect_is_active_high = slot_data->detect_is_active_high;
        slot->sdc_reg = sdc_reg;
        slot->sdio_irq = sdio_irq;

        dev_dbg(&mmc->class_dev,
                "slot[%u]: bus_width=%u, detect_pin=%d, "
                "detect_is_active_high=%s, wp_pin=%d\n",
                id, slot_data->bus_width, slot_data->detect_pin,
                slot_data->detect_is_active_high ? "true" : "false",
                slot_data->wp_pin);

        mmc->ops = &atmci_ops;
        mmc->f_min = DIV_ROUND_UP(host->bus_hz, 512);
        mmc->f_max = host->bus_hz / 2;
        mmc->ocr_avail  = MMC_VDD_32_33 | MMC_VDD_33_34;
        if (sdio_irq)
                mmc->caps |= MMC_CAP_SDIO_IRQ;
        if (host->caps.has_highspeed)
                mmc->caps |= MMC_CAP_SD_HIGHSPEED;
        /*
         * Without the read/write proof capability, it is strongly suggested to
         * use only one bit for data to prevent fifo underruns and overruns
         * which will corrupt data.
         */
        if ((slot_data->bus_width >= 4) && host->caps.has_rwproof)
                mmc->caps |= MMC_CAP_4_BIT_DATA;

        if (atmci_get_version(host) < 0x200) {
                mmc->max_segs = 256;
                mmc->max_blk_size = 4095;
                mmc->max_blk_count = 256;
                mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count;
                mmc->max_seg_size = mmc->max_blk_size * mmc->max_segs;
        } else {
                mmc->max_segs = 64;
                mmc->max_req_size = 32768 * 512;
                mmc->max_blk_size = 32768;
                mmc->max_blk_count = 512;
        }

        /* Assume card is present initially */
        set_bit(ATMCI_CARD_PRESENT, &slot->flags);
        if (gpio_is_valid(slot->detect_pin)) {
                if (gpio_request(slot->detect_pin, "mmc_detect")) {
                        dev_dbg(&mmc->class_dev, "no detect pin available\n");
                        slot->detect_pin = -EBUSY;
                } else if (gpio_get_value(slot->detect_pin) ^
                                slot->detect_is_active_high) {
                        clear_bit(ATMCI_CARD_PRESENT, &slot->flags);
                }
        }

        if (!gpio_is_valid(slot->detect_pin))
                mmc->caps |= MMC_CAP_NEEDS_POLL;

        if (gpio_is_valid(slot->wp_pin)) {
                if (gpio_request(slot->wp_pin, "mmc_wp")) {
                        dev_dbg(&mmc->class_dev, "no WP pin available\n");
                        slot->wp_pin = -EBUSY;
                }
        }

        host->slot[id] = slot;
        mmc_add_host(mmc);

        if (gpio_is_valid(slot->detect_pin)) {
                int ret;

                setup_timer(&slot->detect_timer, atmci_detect_change,
                                (unsigned long)slot);

                ret = request_irq(gpio_to_irq(slot->detect_pin),
                                atmci_detect_interrupt,
                                IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
                                "mmc-detect", slot);
                if (ret) {
                        dev_dbg(&mmc->class_dev,
                                "could not request IRQ %d for detect pin\n",
                                gpio_to_irq(slot->detect_pin));
                        gpio_free(slot->detect_pin);
                        slot->detect_pin = -EBUSY;
                }
        }

        atmci_init_debugfs(slot);

        return 0;
}

static void __exit atmci_cleanup_slot(struct atmel_mci_slot *slot,
                unsigned int id)
{
        /* Debugfs stuff is cleaned up by mmc core */

        set_bit(ATMCI_SHUTDOWN, &slot->flags);
        smp_wmb();

        mmc_remove_host(slot->mmc);

        if (gpio_is_valid(slot->detect_pin)) {
                int pin = slot->detect_pin;

                free_irq(gpio_to_irq(pin), slot);
                del_timer_sync(&slot->detect_timer);
                gpio_free(pin);
        }
        if (gpio_is_valid(slot->wp_pin))
                gpio_free(slot->wp_pin);

        slot->host->slot[id] = NULL;
        mmc_free_host(slot->mmc);
}

static bool atmci_filter(struct dma_chan *chan, void *pdata)
{
        struct mci_platform_data *sl_pdata = pdata;
        struct mci_dma_data *sl;

        if (!sl_pdata)
                return false;

        sl = sl_pdata->dma_slave;
        if (sl && find_slave_dev(sl) == chan->device->dev) {
                chan->private = slave_data_ptr(sl);
                return true;
        } else {
                return false;
        }
}

static bool atmci_configure_dma(struct atmel_mci *host)
{
        struct mci_platform_data        *pdata;
        dma_cap_mask_t mask;

        if (host == NULL)
                return false;

        pdata = host->pdev->dev.platform_data;

        dma_cap_zero(mask);
        dma_cap_set(DMA_SLAVE, mask);

        host->dma.chan = dma_request_slave_channel_compat(mask, atmci_filter, pdata,
                                                          &host->pdev->dev, "rxtx");
        if (!host->dma.chan) {
                dev_warn(&host->pdev->dev, "no DMA channel available\n");
                return false;
        } else {
                dev_info(&host->pdev->dev,
                                        "using %s for DMA transfers\n",
                                        dma_chan_name(host->dma.chan));

                host->dma_conf.src_addr = host->mapbase + ATMCI_RDR;
                host->dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
                host->dma_conf.src_maxburst = 1;
                host->dma_conf.dst_addr = host->mapbase + ATMCI_TDR;
                host->dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
                host->dma_conf.dst_maxburst = 1;
                host->dma_conf.device_fc = false;
                return true;
        }
}

/*
 * HSMCI (High Speed MCI) module is not fully compatible with MCI module.
 * HSMCI provides DMA support and a new config register but no more supports
 * PDC.
 */
static void __init atmci_get_cap(struct atmel_mci *host)
{
        unsigned int version;

        version = atmci_get_version(host);
        dev_info(&host->pdev->dev,
                        "version: 0x%x\n", version);

        host->caps.has_dma_conf_reg = 0;
        host->caps.has_pdc = ATMCI_PDC_CONNECTED;
        host->caps.has_cfg_reg = 0;
        host->caps.has_cstor_reg = 0;
        host->caps.has_highspeed = 0;
        host->caps.has_rwproof = 0;
        host->caps.has_odd_clk_div = 0;
        host->caps.has_bad_data_ordering = 1;
        host->caps.need_reset_after_xfer = 1;
        host->caps.need_blksz_mul_4 = 1;
        host->caps.need_notbusy_for_read_ops = 0;

        /* keep only major version number */
        switch (version & 0xf00) {
        case 0x500:
                host->caps.has_odd_clk_div = 1;
        case 0x400:
        case 0x300:
                host->caps.has_dma_conf_reg = 1;
                host->caps.has_pdc = 0;
                host->caps.has_cfg_reg = 1;
                host->caps.has_cstor_reg = 1;
                host->caps.has_highspeed = 1;
        case 0x200:
                host->caps.has_rwproof = 1;
                host->caps.need_blksz_mul_4 = 0;
                host->caps.need_notbusy_for_read_ops = 1;
        case 0x100:
                host->caps.has_bad_data_ordering = 0;
                host->caps.need_reset_after_xfer = 0;
        case 0x0:
                break;
        default:
                host->caps.has_pdc = 0;
                dev_warn(&host->pdev->dev,
                                "Unmanaged mci version, set minimum capabilities\n");
                break;
        }
}

static int __init atmci_probe(struct platform_device *pdev)
{
        struct mci_platform_data        *pdata;
        struct atmel_mci                *host;
        struct resource                 *regs;
        unsigned int                    nr_slots;
        int                             irq;
        int                             ret;

        regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!regs)
                return -ENXIO;
        pdata = pdev->dev.platform_data;
        if (!pdata) {
                pdata = atmci_of_init(pdev);
                if (IS_ERR(pdata)) {
                        dev_err(&pdev->dev, "platform data not available\n");
                        return PTR_ERR(pdata);
                }
        }

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;

        host = kzalloc(sizeof(struct atmel_mci), GFP_KERNEL);
        if (!host)
                return -ENOMEM;

        host->pdev = pdev;
        spin_lock_init(&host->lock);
        INIT_LIST_HEAD(&host->queue);

        host->mck = clk_get(&pdev->dev, "mci_clk");
        if (IS_ERR(host->mck)) {
                ret = PTR_ERR(host->mck);
                goto err_clk_get;
        }

        ret = -ENOMEM;
        host->regs = ioremap(regs->start, resource_size(regs));
        if (!host->regs)
                goto err_ioremap;

        clk_enable(host->mck);
        atmci_writel(host, ATMCI_CR, ATMCI_CR_SWRST);
        host->bus_hz = clk_get_rate(host->mck);
        clk_disable(host->mck);

        host->mapbase = regs->start;

        tasklet_init(&host->tasklet, atmci_tasklet_func, (unsigned long)host);

        ret = request_irq(irq, atmci_interrupt, 0, dev_name(&pdev->dev), host);
        if (ret)
                goto err_request_irq;

        /* Get MCI capabilities and set operations according to it */
        atmci_get_cap(host);
        if (atmci_configure_dma(host)) {
                host->prepare_data = &atmci_prepare_data_dma;
                host->submit_data = &atmci_submit_data_dma;
                host->stop_transfer = &atmci_stop_transfer_dma;
        } else if (host->caps.has_pdc) {
                dev_info(&pdev->dev, "using PDC\n");
                host->prepare_data = &atmci_prepare_data_pdc;
                host->submit_data = &atmci_submit_data_pdc;
                host->stop_transfer = &atmci_stop_transfer_pdc;
        } else {
                dev_info(&pdev->dev, "using PIO\n");
                host->prepare_data = &atmci_prepare_data;
                host->submit_data = &atmci_submit_data;
                host->stop_transfer = &atmci_stop_transfer;
        }

        platform_set_drvdata(pdev, host);

        setup_timer(&host->timer, atmci_timeout_timer, (unsigned long)host);

        /* We need at least one slot to succeed */
        nr_slots = 0;
        ret = -ENODEV;
        if (pdata->slot[0].bus_width) {
                ret = atmci_init_slot(host, &pdata->slot[0],
                                0, ATMCI_SDCSEL_SLOT_A, ATMCI_SDIOIRQA);
                if (!ret) {
                        nr_slots++;
                        host->buf_size = host->slot[0]->mmc->max_req_size;
                }
        }
        if (pdata->slot[1].bus_width) {
                ret = atmci_init_slot(host, &pdata->slot[1],
                                1, ATMCI_SDCSEL_SLOT_B, ATMCI_SDIOIRQB);
                if (!ret) {
                        nr_slots++;
                        if (host->slot[1]->mmc->max_req_size > host->buf_size)
                                host->buf_size =
                                        host->slot[1]->mmc->max_req_size;
                }
        }

        if (!nr_slots) {
                dev_err(&pdev->dev, "init failed: no slot defined\n");
                goto err_init_slot;
        }

        if (!host->caps.has_rwproof) {
                host->buffer = dma_alloc_coherent(&pdev->dev, host->buf_size,
                                                  &host->buf_phys_addr,
                                                  GFP_KERNEL);
                if (!host->buffer) {
                        ret = -ENOMEM;
                        dev_err(&pdev->dev, "buffer allocation failed\n");
                        goto err_init_slot;
                }
        }

        dev_info(&pdev->dev,
                        "Atmel MCI controller at 0x%08lx irq %d, %u slots\n",
                        host->mapbase, irq, nr_slots);

        return 0;

err_init_slot:
        if (host->dma.chan)
                dma_release_channel(host->dma.chan);
        free_irq(irq, host);
err_request_irq:
        iounmap(host->regs);
err_ioremap:
        clk_put(host->mck);
err_clk_get:
        kfree(host);
        return ret;
}

static int __exit atmci_remove(struct platform_device *pdev)
{
        struct atmel_mci        *host = platform_get_drvdata(pdev);
        unsigned int            i;

        if (host->buffer)
                dma_free_coherent(&pdev->dev, host->buf_size,
                                  host->buffer, host->buf_phys_addr);

        for (i = 0; i < ATMCI_MAX_NR_SLOTS; i++) {
                if (host->slot[i])
                        atmci_cleanup_slot(host->slot[i], i);
        }

        clk_enable(host->mck);
        atmci_writel(host, ATMCI_IDR, ~0UL);
        atmci_writel(host, ATMCI_CR, ATMCI_CR_MCIDIS);
        atmci_readl(host, ATMCI_SR);
        clk_disable(host->mck);

        if (host->dma.chan)
                dma_release_channel(host->dma.chan);

        free_irq(platform_get_irq(pdev, 0), host);
        iounmap(host->regs);

        clk_put(host->mck);
        kfree(host);

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int atmci_suspend(struct device *dev)
{
        struct atmel_mci *host = dev_get_drvdata(dev);
        int i;

         for (i = 0; i < ATMCI_MAX_NR_SLOTS; i++) {
                struct atmel_mci_slot *slot = host->slot[i];
                int ret;

                if (!slot)
                        continue;
                ret = mmc_suspend_host(slot->mmc);
                if (ret < 0) {
                        while (--i >= 0) {
                                slot = host->slot[i];
                                if (slot
                                && test_bit(ATMCI_SUSPENDED, &slot->flags)) {
                                        mmc_resume_host(host->slot[i]->mmc);
                                        clear_bit(ATMCI_SUSPENDED, &slot->flags);
                                }
                        }
                        return ret;
                } else {
                        set_bit(ATMCI_SUSPENDED, &slot->flags);
                }
        }

        return 0;
}

static int atmci_resume(struct device *dev)
{
        struct atmel_mci *host = dev_get_drvdata(dev);
        int i;
        int ret = 0;

        for (i = 0; i < ATMCI_MAX_NR_SLOTS; i++) {
                struct atmel_mci_slot *slot = host->slot[i];
                int err;

                slot = host->slot[i];
                if (!slot)
                        continue;
                if (!test_bit(ATMCI_SUSPENDED, &slot->flags))
                        continue;
                err = mmc_resume_host(slot->mmc);
                if (err < 0)
                        ret = err;
                else
                        clear_bit(ATMCI_SUSPENDED, &slot->flags);
        }

        return ret;
}
#endif

static SIMPLE_DEV_PM_OPS(atmci_pm, atmci_suspend, atmci_resume);

static struct platform_driver atmci_driver = {
        .remove         = __exit_p(atmci_remove),
        .driver         = {
                .name           = "atmel_mci",
                .pm             = &atmci_pm,
                .of_match_table = of_match_ptr(atmci_dt_ids),
        },
};

static int __init atmci_init(void)
{
        return platform_driver_probe(&atmci_driver, atmci_probe);
}

static void __exit atmci_exit(void)
{
        platform_driver_unregister(&atmci_driver);
}

late_initcall(atmci_init); /* try to load after dma driver when built-in */
module_exit(atmci_exit);

MODULE_DESCRIPTION("Atmel Multimedia Card Interface driver");
MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
MODULE_LICENSE("GPL v2");