/*
 * davinci_mmc.c - TI DaVinci MMC/SD/SDIO driver
 *
 * Copyright (C) 2006 Texas Instruments.
 *       Original author: Purushotam Kumar
 * Copyright (C) 2009 David Brownell
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/cpufreq.h>
#include <linux/mmc/host.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/mmc/mmc.h>

#include <mach/mmc.h>
#include <mach/edma.h>

/*
 * Register Definitions
 */
#define DAVINCI_MMCCTL       0x00 /* Control Register                  */
#define DAVINCI_MMCCLK       0x04 /* Memory Clock Control Register     */
#define DAVINCI_MMCST0       0x08 /* Status Register 0                 */
#define DAVINCI_MMCST1       0x0C /* Status Register 1                 */
#define DAVINCI_MMCIM        0x10 /* Interrupt Mask Register           */
#define DAVINCI_MMCTOR       0x14 /* Response Time-Out Register        */
#define DAVINCI_MMCTOD       0x18 /* Data Read Time-Out Register       */
#define DAVINCI_MMCBLEN      0x1C /* Block Length Register             */
#define DAVINCI_MMCNBLK      0x20 /* Number of Blocks Register         */
#define DAVINCI_MMCNBLC      0x24 /* Number of Blocks Counter Register */
#define DAVINCI_MMCDRR       0x28 /* Data Receive Register             */
#define DAVINCI_MMCDXR       0x2C /* Data Transmit Register            */
#define DAVINCI_MMCCMD       0x30 /* Command Register                  */
#define DAVINCI_MMCARGHL     0x34 /* Argument Register                 */
#define DAVINCI_MMCRSP01     0x38 /* Response Register 0 and 1         */
#define DAVINCI_MMCRSP23     0x3C /* Response Register 0 and 1         */
#define DAVINCI_MMCRSP45     0x40 /* Response Register 0 and 1         */
#define DAVINCI_MMCRSP67     0x44 /* Response Register 0 and 1         */
#define DAVINCI_MMCDRSP      0x48 /* Data Response Register            */
#define DAVINCI_MMCETOK      0x4C
#define DAVINCI_MMCCIDX      0x50 /* Command Index Register            */
#define DAVINCI_MMCCKC       0x54
#define DAVINCI_MMCTORC      0x58
#define DAVINCI_MMCTODC      0x5C
#define DAVINCI_MMCBLNC      0x60
#define DAVINCI_SDIOCTL      0x64
#define DAVINCI_SDIOST0      0x68
#define DAVINCI_SDIOIEN      0x6C
#define DAVINCI_SDIOIST      0x70
#define DAVINCI_MMCFIFOCTL   0x74 /* FIFO Control Register             */

/* DAVINCI_MMCCTL definitions */
#define MMCCTL_DATRST         (1 << 0)
#define MMCCTL_CMDRST         (1 << 1)
#define MMCCTL_WIDTH_8_BIT    (1 << 8)
#define MMCCTL_WIDTH_4_BIT    (1 << 2)
#define MMCCTL_DATEG_DISABLED (0 << 6)
#define MMCCTL_DATEG_RISING   (1 << 6)
#define MMCCTL_DATEG_FALLING  (2 << 6)
#define MMCCTL_DATEG_BOTH     (3 << 6)
#define MMCCTL_PERMDR_LE      (0 << 9)
#define MMCCTL_PERMDR_BE      (1 << 9)
#define MMCCTL_PERMDX_LE      (0 << 10)
#define MMCCTL_PERMDX_BE      (1 << 10)

/* DAVINCI_MMCCLK definitions */
#define MMCCLK_CLKEN          (1 << 8)
#define MMCCLK_CLKRT_MASK     (0xFF << 0)

/* IRQ bit definitions, for DAVINCI_MMCST0 and DAVINCI_MMCIM */
#define MMCST0_DATDNE         BIT(0)    /* data done */
#define MMCST0_BSYDNE         BIT(1)    /* busy done */
#define MMCST0_RSPDNE         BIT(2)    /* command done */
#define MMCST0_TOUTRD         BIT(3)    /* data read timeout */
#define MMCST0_TOUTRS         BIT(4)    /* command response timeout */
#define MMCST0_CRCWR          BIT(5)    /* data write CRC error */
#define MMCST0_CRCRD          BIT(6)    /* data read CRC error */
#define MMCST0_CRCRS          BIT(7)    /* command response CRC error */
#define MMCST0_DXRDY          BIT(9)    /* data transmit ready (fifo empty) */
#define MMCST0_DRRDY          BIT(10)   /* data receive ready (data in fifo)*/
#define MMCST0_DATED          BIT(11)   /* DAT3 edge detect */
#define MMCST0_TRNDNE         BIT(12)   /* transfer done */

/* DAVINCI_MMCST1 definitions */
#define MMCST1_BUSY           (1 << 0)

/* DAVINCI_MMCCMD definitions */
#define MMCCMD_CMD_MASK       (0x3F << 0)
#define MMCCMD_PPLEN          (1 << 7)
#define MMCCMD_BSYEXP         (1 << 8)
#define MMCCMD_RSPFMT_MASK    (3 << 9)
#define MMCCMD_RSPFMT_NONE    (0 << 9)
#define MMCCMD_RSPFMT_R1456   (1 << 9)
#define MMCCMD_RSPFMT_R2      (2 << 9)
#define MMCCMD_RSPFMT_R3      (3 << 9)
#define MMCCMD_DTRW           (1 << 11)
#define MMCCMD_STRMTP         (1 << 12)
#define MMCCMD_WDATX          (1 << 13)
#define MMCCMD_INITCK         (1 << 14)
#define MMCCMD_DCLR           (1 << 15)
#define MMCCMD_DMATRIG        (1 << 16)

/* DAVINCI_MMCFIFOCTL definitions */
#define MMCFIFOCTL_FIFORST    (1 << 0)
#define MMCFIFOCTL_FIFODIR_WR (1 << 1)
#define MMCFIFOCTL_FIFODIR_RD (0 << 1)
#define MMCFIFOCTL_FIFOLEV    (1 << 2) /* 0 = 128 bits, 1 = 256 bits */
#define MMCFIFOCTL_ACCWD_4    (0 << 3) /* access width of 4 bytes    */
#define MMCFIFOCTL_ACCWD_3    (1 << 3) /* access width of 3 bytes    */
#define MMCFIFOCTL_ACCWD_2    (2 << 3) /* access width of 2 bytes    */
#define MMCFIFOCTL_ACCWD_1    (3 << 3) /* access width of 1 byte     */

/* DAVINCI_SDIOST0 definitions */
#define SDIOST0_DAT1_HI       BIT(0)

/* DAVINCI_SDIOIEN definitions */
#define SDIOIEN_IOINTEN       BIT(0)

/* DAVINCI_SDIOIST definitions */
#define SDIOIST_IOINT         BIT(0)

/* MMCSD Init clock in Hz in opendrain mode */
#define MMCSD_INIT_CLOCK                200000

/*
 * One scatterlist dma "segment" is at most MAX_CCNT rw_threshold units,
 * and we handle up to MAX_NR_SG segments.  MMC_BLOCK_BOUNCE kicks in only
 * for drivers with max_segs == 1, making the segments bigger (64KB)
 * than the page or two that's otherwise typical. nr_sg (passed from
 * platform data) == 16 gives at least the same throughput boost, using
 * EDMA transfer linkage instead of spending CPU time copying pages.
 */
#define MAX_CCNT        ((1 << 16) - 1)

#define MAX_NR_SG       16

static unsigned rw_threshold = 32;
module_param(rw_threshold, uint, S_IRUGO);
MODULE_PARM_DESC(rw_threshold,
                "Read/Write threshold. Default = 32");

static unsigned poll_threshold = 128;
module_param(poll_threshold, uint, S_IRUGO);
MODULE_PARM_DESC(poll_threshold,
                 "Polling transaction size threshold. Default = 128");

static unsigned poll_loopcount = 32;
module_param(poll_loopcount, uint, S_IRUGO);
MODULE_PARM_DESC(poll_loopcount,
                 "Maximum polling loop count. Default = 32");

static unsigned __initdata use_dma = 1;
module_param(use_dma, uint, 0);
MODULE_PARM_DESC(use_dma, "Whether to use DMA or not. Default = 1");

struct mmc_davinci_host {
        struct mmc_command *cmd;
        struct mmc_data *data;
        struct mmc_host *mmc;
        struct clk *clk;
        unsigned int mmc_input_clk;
        void __iomem *base;
        struct resource *mem_res;
        int mmc_irq, sdio_irq;
        unsigned char bus_mode;

#define DAVINCI_MMC_DATADIR_NONE        0
#define DAVINCI_MMC_DATADIR_READ        1
#define DAVINCI_MMC_DATADIR_WRITE       2
        unsigned char data_dir;
        unsigned char suspended;

        /* buffer is used during PIO of one scatterlist segment, and
         * is updated along with buffer_bytes_left.  bytes_left applies
         * to all N blocks of the PIO transfer.
         */
        u8 *buffer;
        u32 buffer_bytes_left;
        u32 bytes_left;

        u32 rxdma, txdma;
        bool use_dma;
        bool do_dma;
        bool sdio_int;
        bool active_request;

        /* Scatterlist DMA uses one or more parameter RAM entries:
         * the main one (associated with rxdma or txdma) plus zero or
         * more links.  The entries for a given transfer differ only
         * by memory buffer (address, length) and link field.
         */
        struct edmacc_param     tx_template;
        struct edmacc_param     rx_template;
        unsigned                n_link;
        u32                     links[MAX_NR_SG - 1];

        /* For PIO we walk scatterlists one segment at a time. */
        unsigned int            sg_len;
        struct scatterlist *sg;

        /* Version of the MMC/SD controller */
        u8 version;
        /* for ns in one cycle calculation */
        unsigned ns_in_one_cycle;
        /* Number of sg segments */
        u8 nr_sg;
#ifdef CONFIG_CPU_FREQ
        struct notifier_block   freq_transition;
#endif
};

static irqreturn_t mmc_davinci_irq(int irq, void *dev_id);

/* PIO only */
static void mmc_davinci_sg_to_buf(struct mmc_davinci_host *host)
{
        host->buffer_bytes_left = sg_dma_len(host->sg);
        host->buffer = sg_virt(host->sg);
        if (host->buffer_bytes_left > host->bytes_left)
                host->buffer_bytes_left = host->bytes_left;
}

static void davinci_fifo_data_trans(struct mmc_davinci_host *host,
                                        unsigned int n)
{
        u8 *p;
        unsigned int i;

        if (host->buffer_bytes_left == 0) {
                host->sg = sg_next(host->data->sg);
                mmc_davinci_sg_to_buf(host);
        }

        p = host->buffer;
        if (n > host->buffer_bytes_left)
                n = host->buffer_bytes_left;
        host->buffer_bytes_left -= n;
        host->bytes_left -= n;

        /* NOTE:  we never transfer more than rw_threshold bytes
         * to/from the fifo here; there's no I/O overlap.
         * This also assumes that access width( i.e. ACCWD) is 4 bytes
         */
        if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE) {
                for (i = 0; i < (n >> 2); i++) {
                        writel(*((u32 *)p), host->base + DAVINCI_MMCDXR);
                        p = p + 4;
                }
                if (n & 3) {
                        iowrite8_rep(host->base + DAVINCI_MMCDXR, p, (n & 3));
                        p = p + (n & 3);
                }
        } else {
                for (i = 0; i < (n >> 2); i++) {
                        *((u32 *)p) = readl(host->base + DAVINCI_MMCDRR);
                        p  = p + 4;
                }
                if (n & 3) {
                        ioread8_rep(host->base + DAVINCI_MMCDRR, p, (n & 3));
                        p = p + (n & 3);
                }
        }
        host->buffer = p;
}

static void mmc_davinci_start_command(struct mmc_davinci_host *host,
                struct mmc_command *cmd)
{
        u32 cmd_reg = 0;
        u32 im_val;

        dev_dbg(mmc_dev(host->mmc), "CMD%d, arg 0x%08x%s\n",
                cmd->opcode, cmd->arg,
                ({ char *s;
                switch (mmc_resp_type(cmd)) {
                case MMC_RSP_R1:
                        s = ", R1/R5/R6/R7 response";
                        break;
                case MMC_RSP_R1B:
                        s = ", R1b response";
                        break;
                case MMC_RSP_R2:
                        s = ", R2 response";
                        break;
                case MMC_RSP_R3:
                        s = ", R3/R4 response";
                        break;
                default:
                        s = ", (R? response)";
                        break;
                }; s; }));
        host->cmd = cmd;

        switch (mmc_resp_type(cmd)) {
        case MMC_RSP_R1B:
                /* There's some spec confusion about when R1B is
                 * allowed, but if the card doesn't issue a BUSY
                 * then it's harmless for us to allow it.
                 */
                cmd_reg |= MMCCMD_BSYEXP;
                /* FALLTHROUGH */
        case MMC_RSP_R1:                /* 48 bits, CRC */
                cmd_reg |= MMCCMD_RSPFMT_R1456;
                break;
        case MMC_RSP_R2:                /* 136 bits, CRC */
                cmd_reg |= MMCCMD_RSPFMT_R2;
                break;
        case MMC_RSP_R3:                /* 48 bits, no CRC */
                cmd_reg |= MMCCMD_RSPFMT_R3;
                break;
        default:
                cmd_reg |= MMCCMD_RSPFMT_NONE;
                dev_dbg(mmc_dev(host->mmc), "unknown resp_type %04x\n",
                        mmc_resp_type(cmd));
                break;
        }

        /* Set command index */
        cmd_reg |= cmd->opcode;

        /* Enable EDMA transfer triggers */
        if (host->do_dma)
                cmd_reg |= MMCCMD_DMATRIG;

        if (host->version == MMC_CTLR_VERSION_2 && host->data != NULL &&
                        host->data_dir == DAVINCI_MMC_DATADIR_READ)
                cmd_reg |= MMCCMD_DMATRIG;

        /* Setting whether command involves data transfer or not */
        if (cmd->data)
                cmd_reg |= MMCCMD_WDATX;

        /* Setting whether stream or block transfer */
        if (cmd->flags & MMC_DATA_STREAM)
                cmd_reg |= MMCCMD_STRMTP;

        /* Setting whether data read or write */
        if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE)
                cmd_reg |= MMCCMD_DTRW;

        if (host->bus_mode == MMC_BUSMODE_PUSHPULL)
                cmd_reg |= MMCCMD_PPLEN;

        /* set Command timeout */
        writel(0x1FFF, host->base + DAVINCI_MMCTOR);

        /* Enable interrupt (calculate here, defer until FIFO is stuffed). */
        im_val =  MMCST0_RSPDNE | MMCST0_CRCRS | MMCST0_TOUTRS;
        if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE) {
                im_val |= MMCST0_DATDNE | MMCST0_CRCWR;

                if (!host->do_dma)
                        im_val |= MMCST0_DXRDY;
        } else if (host->data_dir == DAVINCI_MMC_DATADIR_READ) {
                im_val |= MMCST0_DATDNE | MMCST0_CRCRD | MMCST0_TOUTRD;

                if (!host->do_dma)
                        im_val |= MMCST0_DRRDY;
        }

        /*
         * Before non-DMA WRITE commands the controller needs priming:
         * FIFO should be populated with 32 bytes i.e. whatever is the FIFO size
         */
        if (!host->do_dma && (host->data_dir == DAVINCI_MMC_DATADIR_WRITE))
                davinci_fifo_data_trans(host, rw_threshold);

        writel(cmd->arg, host->base + DAVINCI_MMCARGHL);
        writel(cmd_reg,  host->base + DAVINCI_MMCCMD);

        host->active_request = true;

        if (!host->do_dma && host->bytes_left <= poll_threshold) {
                u32 count = poll_loopcount;

                while (host->active_request && count--) {
                        mmc_davinci_irq(0, host);
                        cpu_relax();
                }
        }

        if (host->active_request)
                writel(im_val, host->base + DAVINCI_MMCIM);
}

/*----------------------------------------------------------------------*/

/* DMA infrastructure */

static void davinci_abort_dma(struct mmc_davinci_host *host)
{
        int sync_dev;

        if (host->data_dir == DAVINCI_MMC_DATADIR_READ)
                sync_dev = host->rxdma;
        else
                sync_dev = host->txdma;

        edma_stop(sync_dev);
        edma_clean_channel(sync_dev);
}

static void
mmc_davinci_xfer_done(struct mmc_davinci_host *host, struct mmc_data *data);

static void mmc_davinci_dma_cb(unsigned channel, u16 ch_status, void *data)
{
        if (DMA_COMPLETE != ch_status) {
                struct mmc_davinci_host *host = data;

                /* Currently means:  DMA Event Missed, or "null" transfer
                 * request was seen.  In the future, TC errors (like bad
                 * addresses) might be presented too.
                 */
                dev_warn(mmc_dev(host->mmc), "DMA %s error\n",
                        (host->data->flags & MMC_DATA_WRITE)
                                ? "write" : "read");
                host->data->error = -EIO;
                mmc_davinci_xfer_done(host, host->data);
        }
}

/* Set up tx or rx template, to be modified and updated later */
static void __init mmc_davinci_dma_setup(struct mmc_davinci_host *host,
                bool tx, struct edmacc_param *template)
{
        unsigned        sync_dev;
        const u16       acnt = 4;
        const u16       bcnt = rw_threshold >> 2;
        const u16       ccnt = 0;
        u32             src_port = 0;
        u32             dst_port = 0;
        s16             src_bidx, dst_bidx;
        s16             src_cidx, dst_cidx;

        /*
         * A-B Sync transfer:  each DMA request is for one "frame" of
         * rw_threshold bytes, broken into "acnt"-size chunks repeated
         * "bcnt" times.  Each segment needs "ccnt" such frames; since
         * we tell the block layer our mmc->max_seg_size limit, we can
         * trust (later) that it's within bounds.
         *
         * The FIFOs are read/written in 4-byte chunks (acnt == 4) and
         * EDMA will optimize memory operations to use larger bursts.
         */
        if (tx) {
                sync_dev = host->txdma;

                /* src_prt, ccnt, and link to be set up later */
                src_bidx = acnt;
                src_cidx = acnt * bcnt;

                dst_port = host->mem_res->start + DAVINCI_MMCDXR;
                dst_bidx = 0;
                dst_cidx = 0;
        } else {
                sync_dev = host->rxdma;

                src_port = host->mem_res->start + DAVINCI_MMCDRR;
                src_bidx = 0;
                src_cidx = 0;

                /* dst_prt, ccnt, and link to be set up later */
                dst_bidx = acnt;
                dst_cidx = acnt * bcnt;
        }

        /*
         * We can't use FIFO mode for the FIFOs because MMC FIFO addresses
         * are not 256-bit (32-byte) aligned.  So we use INCR, and the W8BIT
         * parameter is ignored.
         */
        edma_set_src(sync_dev, src_port, INCR, W8BIT);
        edma_set_dest(sync_dev, dst_port, INCR, W8BIT);

        edma_set_src_index(sync_dev, src_bidx, src_cidx);
        edma_set_dest_index(sync_dev, dst_bidx, dst_cidx);

        edma_set_transfer_params(sync_dev, acnt, bcnt, ccnt, 8, ABSYNC);

        edma_read_slot(sync_dev, template);

        /* don't bother with irqs or chaining */
        template->opt |= EDMA_CHAN_SLOT(sync_dev) << 12;
}

static void mmc_davinci_send_dma_request(struct mmc_davinci_host *host,
                struct mmc_data *data)
{
        struct edmacc_param     *template;
        int                     channel, slot;
        unsigned                link;
        struct scatterlist      *sg;
        unsigned                sg_len;
        unsigned                bytes_left = host->bytes_left;
        const unsigned          shift = ffs(rw_threshold) - 1;

        if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE) {
                template = &host->tx_template;
                channel = host->txdma;
        } else {
                template = &host->rx_template;
                channel = host->rxdma;
        }

        /* We know sg_len and ccnt will never be out of range because
         * we told the mmc layer which in turn tells the block layer
         * to ensure that it only hands us one scatterlist segment
         * per EDMA PARAM entry.  Update the PARAM
         * entries needed for each segment of this scatterlist.
         */
        for (slot = channel, link = 0, sg = data->sg, sg_len = host->sg_len;
                        sg_len-- != 0 && bytes_left;
                        sg = sg_next(sg), slot = host->links[link++]) {
                u32             buf = sg_dma_address(sg);
                unsigned        count = sg_dma_len(sg);

                template->link_bcntrld = sg_len
                                ? (EDMA_CHAN_SLOT(host->links[link]) << 5)
                                : 0xffff;

                if (count > bytes_left)
                        count = bytes_left;
                bytes_left -= count;

                if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE)
                        template->src = buf;
                else
                        template->dst = buf;
                template->ccnt = count >> shift;

                edma_write_slot(slot, template);
        }

        if (host->version == MMC_CTLR_VERSION_2)
                edma_clear_event(channel);

        edma_start(channel);
}

static int mmc_davinci_start_dma_transfer(struct mmc_davinci_host *host,
                struct mmc_data *data)
{
        int i;
        int mask = rw_threshold - 1;

        host->sg_len = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
                                ((data->flags & MMC_DATA_WRITE)
                                ? DMA_TO_DEVICE
                                : DMA_FROM_DEVICE));

        /* no individual DMA segment should need a partial FIFO */
        for (i = 0; i < host->sg_len; i++) {
                if (sg_dma_len(data->sg + i) & mask) {
                        dma_unmap_sg(mmc_dev(host->mmc),
                                        data->sg, data->sg_len,
                                        (data->flags & MMC_DATA_WRITE)
                                        ? DMA_TO_DEVICE
                                        : DMA_FROM_DEVICE);
                        return -1;
                }
        }

        host->do_dma = 1;
        mmc_davinci_send_dma_request(host, data);

        return 0;
}

static void __init_or_module
davinci_release_dma_channels(struct mmc_davinci_host *host)
{
        unsigned        i;

        if (!host->use_dma)
                return;

        for (i = 0; i < host->n_link; i++)
                edma_free_slot(host->links[i]);

        edma_free_channel(host->txdma);
        edma_free_channel(host->rxdma);
}

static int __init davinci_acquire_dma_channels(struct mmc_davinci_host *host)
{
        u32 link_size;
        int r, i;

        /* Acquire master DMA write channel */
        r = edma_alloc_channel(host->txdma, mmc_davinci_dma_cb, host,
                        EVENTQ_DEFAULT);
        if (r < 0) {
                dev_warn(mmc_dev(host->mmc), "alloc %s channel err %d\n",
                                "tx", r);
                return r;
        }
        mmc_davinci_dma_setup(host, true, &host->tx_template);

        /* Acquire master DMA read channel */
        r = edma_alloc_channel(host->rxdma, mmc_davinci_dma_cb, host,
                        EVENTQ_DEFAULT);
        if (r < 0) {
                dev_warn(mmc_dev(host->mmc), "alloc %s channel err %d\n",
                                "rx", r);
                goto free_master_write;
        }
        mmc_davinci_dma_setup(host, false, &host->rx_template);

        /* Allocate parameter RAM slots, which will later be bound to a
         * channel as needed to handle a scatterlist.
         */
        link_size = min_t(unsigned, host->nr_sg, ARRAY_SIZE(host->links));
        for (i = 0; i < link_size; i++) {
                r = edma_alloc_slot(EDMA_CTLR(host->txdma), EDMA_SLOT_ANY);
                if (r < 0) {
                        dev_dbg(mmc_dev(host->mmc), "dma PaRAM alloc --> %d\n",
                                r);
                        break;
                }
                host->links[i] = r;
        }
        host->n_link = i;

        return 0;

free_master_write:
        edma_free_channel(host->txdma);

        return r;
}

/*----------------------------------------------------------------------*/

static void
mmc_davinci_prepare_data(struct mmc_davinci_host *host, struct mmc_request *req)
{
        int fifo_lev = (rw_threshold == 32) ? MMCFIFOCTL_FIFOLEV : 0;
        int timeout;
        struct mmc_data *data = req->data;

        if (host->version == MMC_CTLR_VERSION_2)
                fifo_lev = (rw_threshold == 64) ? MMCFIFOCTL_FIFOLEV : 0;

        host->data = data;
        if (data == NULL) {
                host->data_dir = DAVINCI_MMC_DATADIR_NONE;
                writel(0, host->base + DAVINCI_MMCBLEN);
                writel(0, host->base + DAVINCI_MMCNBLK);
                return;
        }

        dev_dbg(mmc_dev(host->mmc), "%s %s, %d blocks of %d bytes\n",
                (data->flags & MMC_DATA_STREAM) ? "stream" : "block",
                (data->flags & MMC_DATA_WRITE) ? "write" : "read",
                data->blocks, data->blksz);
        dev_dbg(mmc_dev(host->mmc), "  DTO %d cycles + %d ns\n",
                data->timeout_clks, data->timeout_ns);
        timeout = data->timeout_clks +
                (data->timeout_ns / host->ns_in_one_cycle);
        if (timeout > 0xffff)
                timeout = 0xffff;

        writel(timeout, host->base + DAVINCI_MMCTOD);
        writel(data->blocks, host->base + DAVINCI_MMCNBLK);
        writel(data->blksz, host->base + DAVINCI_MMCBLEN);

        /* Configure the FIFO */
        switch (data->flags & MMC_DATA_WRITE) {
        case MMC_DATA_WRITE:
                host->data_dir = DAVINCI_MMC_DATADIR_WRITE;
                writel(fifo_lev | MMCFIFOCTL_FIFODIR_WR | MMCFIFOCTL_FIFORST,
                        host->base + DAVINCI_MMCFIFOCTL);
                writel(fifo_lev | MMCFIFOCTL_FIFODIR_WR,
                        host->base + DAVINCI_MMCFIFOCTL);
                break;

        default:
                host->data_dir = DAVINCI_MMC_DATADIR_READ;
                writel(fifo_lev | MMCFIFOCTL_FIFODIR_RD | MMCFIFOCTL_FIFORST,
                        host->base + DAVINCI_MMCFIFOCTL);
                writel(fifo_lev | MMCFIFOCTL_FIFODIR_RD,
                        host->base + DAVINCI_MMCFIFOCTL);
                break;
        }

        host->buffer = NULL;
        host->bytes_left = data->blocks * data->blksz;

        /* For now we try to use DMA whenever we won't need partial FIFO
         * reads or writes, either for the whole transfer (as tested here)
         * or for any individual scatterlist segment (tested when we call
         * start_dma_transfer).
         *
         * While we *could* change that, unusual block sizes are rarely
         * used.  The occasional fallback to PIO should't hurt.
         */
        if (host->use_dma && (host->bytes_left & (rw_threshold - 1)) == 0
                        && mmc_davinci_start_dma_transfer(host, data) == 0) {
                /* zero this to ensure we take no PIO paths */
                host->bytes_left = 0;
        } else {
                /* Revert to CPU Copy */
                host->sg_len = data->sg_len;
                host->sg = host->data->sg;
                mmc_davinci_sg_to_buf(host);
        }
}

static void mmc_davinci_request(struct mmc_host *mmc, struct mmc_request *req)
{
        struct mmc_davinci_host *host = mmc_priv(mmc);
        unsigned long timeout = jiffies + msecs_to_jiffies(900);
        u32 mmcst1 = 0;

        /* Card may still be sending BUSY after a previous operation,
         * typically some kind of write.  If so, we can't proceed yet.
         */
        while (time_before(jiffies, timeout)) {
                mmcst1  = readl(host->base + DAVINCI_MMCST1);
                if (!(mmcst1 & MMCST1_BUSY))
                        break;
                cpu_relax();
        }
        if (mmcst1 & MMCST1_BUSY) {
                dev_err(mmc_dev(host->mmc), "still BUSY? bad ... \n");
                req->cmd->error = -ETIMEDOUT;
                mmc_request_done(mmc, req);
                return;
        }

        host->do_dma = 0;
        mmc_davinci_prepare_data(host, req);
        mmc_davinci_start_command(host, req->cmd);
}

static unsigned int calculate_freq_for_card(struct mmc_davinci_host *host,
        unsigned int mmc_req_freq)
{
        unsigned int mmc_freq = 0, mmc_pclk = 0, mmc_push_pull_divisor = 0;

        mmc_pclk = host->mmc_input_clk;
        if (mmc_req_freq && mmc_pclk > (2 * mmc_req_freq))
                mmc_push_pull_divisor = ((unsigned int)mmc_pclk
                                / (2 * mmc_req_freq)) - 1;
        else
                mmc_push_pull_divisor = 0;

        mmc_freq = (unsigned int)mmc_pclk
                / (2 * (mmc_push_pull_divisor + 1));

        if (mmc_freq > mmc_req_freq)
                mmc_push_pull_divisor = mmc_push_pull_divisor + 1;
        /* Convert ns to clock cycles */
        if (mmc_req_freq <= 400000)
                host->ns_in_one_cycle = (1000000) / (((mmc_pclk
                                / (2 * (mmc_push_pull_divisor + 1)))/1000));
        else
                host->ns_in_one_cycle = (1000000) / (((mmc_pclk
                                / (2 * (mmc_push_pull_divisor + 1)))/1000000));

        return mmc_push_pull_divisor;
}

static void calculate_clk_divider(struct mmc_host *mmc, struct mmc_ios *ios)
{
        unsigned int open_drain_freq = 0, mmc_pclk = 0;
        unsigned int mmc_push_pull_freq = 0;
        struct mmc_davinci_host *host = mmc_priv(mmc);

        if (ios->bus_mode == MMC_BUSMODE_OPENDRAIN) {
                u32 temp;

                /* Ignoring the init clock value passed for fixing the inter
                 * operability with different cards.
                 */
                open_drain_freq = ((unsigned int)mmc_pclk
                                / (2 * MMCSD_INIT_CLOCK)) - 1;

                if (open_drain_freq > 0xFF)
                        open_drain_freq = 0xFF;

                temp = readl(host->base + DAVINCI_MMCCLK) & ~MMCCLK_CLKRT_MASK;
                temp |= open_drain_freq;
                writel(temp, host->base + DAVINCI_MMCCLK);

                /* Convert ns to clock cycles */
                host->ns_in_one_cycle = (1000000) / (MMCSD_INIT_CLOCK/1000);
        } else {
                u32 temp;
                mmc_push_pull_freq = calculate_freq_for_card(host, ios->clock);

                if (mmc_push_pull_freq > 0xFF)
                        mmc_push_pull_freq = 0xFF;

                temp = readl(host->base + DAVINCI_MMCCLK) & ~MMCCLK_CLKEN;
                writel(temp, host->base + DAVINCI_MMCCLK);

                udelay(10);

                temp = readl(host->base + DAVINCI_MMCCLK) & ~MMCCLK_CLKRT_MASK;
                temp |= mmc_push_pull_freq;
                writel(temp, host->base + DAVINCI_MMCCLK);

                writel(temp | MMCCLK_CLKEN, host->base + DAVINCI_MMCCLK);

                udelay(10);
        }
}

static void mmc_davinci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
        struct mmc_davinci_host *host = mmc_priv(mmc);
        struct platform_device *pdev = to_platform_device(mmc->parent);
        struct davinci_mmc_config *config = pdev->dev.platform_data;

        dev_dbg(mmc_dev(host->mmc),
                "clock %dHz busmode %d powermode %d Vdd %04x\n",
                ios->clock, ios->bus_mode, ios->power_mode,
                ios->vdd);

        switch (ios->power_mode) {
        case MMC_POWER_OFF:
                if (config && config->set_power)
                        config->set_power(pdev->id, false);
                break;
        case MMC_POWER_UP:
                if (config && config->set_power)
                        config->set_power(pdev->id, true);
                break;
        }

        switch (ios->bus_width) {
        case MMC_BUS_WIDTH_8:
                dev_dbg(mmc_dev(host->mmc), "Enabling 8 bit mode\n");
                writel((readl(host->base + DAVINCI_MMCCTL) &
                        ~MMCCTL_WIDTH_4_BIT) | MMCCTL_WIDTH_8_BIT,
                        host->base + DAVINCI_MMCCTL);
                break;
        case MMC_BUS_WIDTH_4:
                dev_dbg(mmc_dev(host->mmc), "Enabling 4 bit mode\n");
                if (host->version == MMC_CTLR_VERSION_2)
                        writel((readl(host->base + DAVINCI_MMCCTL) &
                                ~MMCCTL_WIDTH_8_BIT) | MMCCTL_WIDTH_4_BIT,
                                host->base + DAVINCI_MMCCTL);
                else
                        writel(readl(host->base + DAVINCI_MMCCTL) |
                                MMCCTL_WIDTH_4_BIT,
                                host->base + DAVINCI_MMCCTL);
                break;
        case MMC_BUS_WIDTH_1:
                dev_dbg(mmc_dev(host->mmc), "Enabling 1 bit mode\n");
                if (host->version == MMC_CTLR_VERSION_2)
                        writel(readl(host->base + DAVINCI_MMCCTL) &
                                ~(MMCCTL_WIDTH_8_BIT | MMCCTL_WIDTH_4_BIT),
                                host->base + DAVINCI_MMCCTL);
                else
                        writel(readl(host->base + DAVINCI_MMCCTL) &
                                ~MMCCTL_WIDTH_4_BIT,
                                host->base + DAVINCI_MMCCTL);
                break;
        }

        calculate_clk_divider(mmc, ios);

        host->bus_mode = ios->bus_mode;
        if (ios->power_mode == MMC_POWER_UP) {
                unsigned long timeout = jiffies + msecs_to_jiffies(50);
                bool lose = true;

                /* Send clock cycles, poll completion */
                writel(0, host->base + DAVINCI_MMCARGHL);
                writel(MMCCMD_INITCK, host->base + DAVINCI_MMCCMD);
                while (time_before(jiffies, timeout)) {
                        u32 tmp = readl(host->base + DAVINCI_MMCST0);

                        if (tmp & MMCST0_RSPDNE) {
                                lose = false;
                                break;
                        }
                        cpu_relax();
                }
                if (lose)
                        dev_warn(mmc_dev(host->mmc), "powerup timeout\n");
        }

        /* FIXME on power OFF, reset things ... */
}

static void
mmc_davinci_xfer_done(struct mmc_davinci_host *host, struct mmc_data *data)
{
        host->data = NULL;

        if (host->mmc->caps & MMC_CAP_SDIO_IRQ) {
                /*
                 * SDIO Interrupt Detection work-around as suggested by
                 * Davinci Errata (TMS320DM355 Silicon Revision 1.1 Errata
                 * 2.1.6): Signal SDIO interrupt only if it is enabled by core
                 */
                if (host->sdio_int && !(readl(host->base + DAVINCI_SDIOST0) &
                                        SDIOST0_DAT1_HI)) {
                        writel(SDIOIST_IOINT, host->base + DAVINCI_SDIOIST);
                        mmc_signal_sdio_irq(host->mmc);
                }
        }

        if (host->do_dma) {
                davinci_abort_dma(host);

                dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
                             (data->flags & MMC_DATA_WRITE)
                             ? DMA_TO_DEVICE
                             : DMA_FROM_DEVICE);
                host->do_dma = false;
        }
        host->data_dir = DAVINCI_MMC_DATADIR_NONE;

        if (!data->stop || (host->cmd && host->cmd->error)) {
                mmc_request_done(host->mmc, data->mrq);
                writel(0, host->base + DAVINCI_MMCIM);
                host->active_request = false;
        } else
                mmc_davinci_start_command(host, data->stop);
}

static void mmc_davinci_cmd_done(struct mmc_davinci_host *host,
                                 struct mmc_command *cmd)
{
        host->cmd = NULL;

        if (cmd->flags & MMC_RSP_PRESENT) {
                if (cmd->flags & MMC_RSP_136) {
                        /* response type 2 */
                        cmd->resp[3] = readl(host->base + DAVINCI_MMCRSP01);
                        cmd->resp[2] = readl(host->base + DAVINCI_MMCRSP23);
                        cmd->resp[1] = readl(host->base + DAVINCI_MMCRSP45);
                        cmd->resp[0] = readl(host->base + DAVINCI_MMCRSP67);
                } else {
                        /* response types 1, 1b, 3, 4, 5, 6 */
                        cmd->resp[0] = readl(host->base + DAVINCI_MMCRSP67);
                }
        }

        if (host->data == NULL || cmd->error) {
                if (cmd->error == -ETIMEDOUT)
                        cmd->mrq->cmd->retries = 0;
                mmc_request_done(host->mmc, cmd->mrq);
                writel(0, host->base + DAVINCI_MMCIM);
                host->active_request = false;
        }
}

static inline void mmc_davinci_reset_ctrl(struct mmc_davinci_host *host,
                                                                int val)
{
        u32 temp;

        temp = readl(host->base + DAVINCI_MMCCTL);
        if (val)        /* reset */
                temp |= MMCCTL_CMDRST | MMCCTL_DATRST;
        else            /* enable */
                temp &= ~(MMCCTL_CMDRST | MMCCTL_DATRST);

        writel(temp, host->base + DAVINCI_MMCCTL);
        udelay(10);
}

static void
davinci_abort_data(struct mmc_davinci_host *host, struct mmc_data *data)
{
        mmc_davinci_reset_ctrl(host, 1);
        mmc_davinci_reset_ctrl(host, 0);
}

static irqreturn_t mmc_davinci_sdio_irq(int irq, void *dev_id)
{
        struct mmc_davinci_host *host = dev_id;
        unsigned int status;

        status = readl(host->base + DAVINCI_SDIOIST);
        if (status & SDIOIST_IOINT) {
                dev_dbg(mmc_dev(host->mmc),
                        "SDIO interrupt status %x\n", status);
                writel(status | SDIOIST_IOINT, host->base + DAVINCI_SDIOIST);
                mmc_signal_sdio_irq(host->mmc);
        }
        return IRQ_HANDLED;
}

static irqreturn_t mmc_davinci_irq(int irq, void *dev_id)
{
        struct mmc_davinci_host *host = (struct mmc_davinci_host *)dev_id;
        unsigned int status, qstatus;
        int end_command = 0;
        int end_transfer = 0;
        struct mmc_data *data = host->data;

        if (host->cmd == NULL && host->data == NULL) {
                status = readl(host->base + DAVINCI_MMCST0);
                dev_dbg(mmc_dev(host->mmc),
                        "Spurious interrupt 0x%04x\n", status);
                /* Disable the interrupt from mmcsd */
                writel(0, host->base + DAVINCI_MMCIM);
                return IRQ_NONE;
        }

        status = readl(host->base + DAVINCI_MMCST0);
        qstatus = status;

        /* handle FIFO first when using PIO for data.
         * bytes_left will decrease to zero as I/O progress and status will
         * read zero over iteration because this controller status
         * register(MMCST0) reports any status only once and it is cleared
         * by read. So, it is not unbouned loop even in the case of
         * non-dma.
         */
        if (host->bytes_left && (status & (MMCST0_DXRDY | MMCST0_DRRDY))) {
                unsigned long im_val;

                /*
                 * If interrupts fire during the following loop, they will be
                 * handled by the handler, but the PIC will still buffer these.
                 * As a result, the handler will be called again to serve these
                 * needlessly. In order to avoid these spurious interrupts,
                 * keep interrupts masked during the loop.
                 */
                im_val = readl(host->base + DAVINCI_MMCIM);
                writel(0, host->base + DAVINCI_MMCIM);

                do {
                        davinci_fifo_data_trans(host, rw_threshold);
                        status = readl(host->base + DAVINCI_MMCST0);
                        qstatus |= status;
                } while (host->bytes_left &&
                         (status & (MMCST0_DXRDY | MMCST0_DRRDY)));

                /*
                 * If an interrupt is pending, it is assumed it will fire when
                 * it is unmasked. This assumption is also taken when the MMCIM
                 * is first set. Otherwise, writing to MMCIM after reading the
                 * status is race-prone.
                 */
                writel(im_val, host->base + DAVINCI_MMCIM);
        }

        if (qstatus & MMCST0_DATDNE) {
                /* All blocks sent/received, and CRC checks passed */
                if (data != NULL) {
                        if ((host->do_dma == 0) && (host->bytes_left > 0)) {
                                /* if datasize < rw_threshold
                                 * no RX ints are generated
                                 */
                                davinci_fifo_data_trans(host, host->bytes_left);
                        }
                        end_transfer = 1;
                        data->bytes_xfered = data->blocks * data->blksz;
                } else {
                        dev_err(mmc_dev(host->mmc),
                                        "DATDNE with no host->data\n");
                }
        }

        if (qstatus & MMCST0_TOUTRD) {
                /* Read data timeout */
                data->error = -ETIMEDOUT;
                end_transfer = 1;

                dev_dbg(mmc_dev(host->mmc),
                        "read data timeout, status %x\n",
                        qstatus);

                davinci_abort_data(host, data);
        }

        if (qstatus & (MMCST0_CRCWR | MMCST0_CRCRD)) {
                /* Data CRC error */
                data->error = -EILSEQ;
                end_transfer = 1;

                /* NOTE:  this controller uses CRCWR to report both CRC
                 * errors and timeouts (on writes).  MMCDRSP values are
                 * only weakly documented, but 0x9f was clearly a timeout
                 * case and the two three-bit patterns in various SD specs
                 * (101, 010) aren't part of it ...
                 */
                if (qstatus & MMCST0_CRCWR) {
                        u32 temp = readb(host->base + DAVINCI_MMCDRSP);

                        if (temp == 0x9f)
                                data->error = -ETIMEDOUT;
                }
                dev_dbg(mmc_dev(host->mmc), "data %s %s error\n",
                        (qstatus & MMCST0_CRCWR) ? "write" : "read",
                        (data->error == -ETIMEDOUT) ? "timeout" : "CRC");

                davinci_abort_data(host, data);
        }

        if (qstatus & MMCST0_TOUTRS) {
                /* Command timeout */
                if (host->cmd) {
                        dev_dbg(mmc_dev(host->mmc),
                                "CMD%d timeout, status %x\n",
                                host->cmd->opcode, qstatus);
                        host->cmd->error = -ETIMEDOUT;
                        if (data) {
                                end_transfer = 1;
                                davinci_abort_data(host, data);
                        } else
                                end_command = 1;
                }
        }

        if (qstatus & MMCST0_CRCRS) {
                /* Command CRC error */
                dev_dbg(mmc_dev(host->mmc), "Command CRC error\n");
                if (host->cmd) {
                        host->cmd->error = -EILSEQ;
                        end_command = 1;
                }
        }

        if (qstatus & MMCST0_RSPDNE) {
                /* End of command phase */
                end_command = (int) host->cmd;
        }

        if (end_command)
                mmc_davinci_cmd_done(host, host->cmd);
        if (end_transfer)
                mmc_davinci_xfer_done(host, data);
        return IRQ_HANDLED;
}

static int mmc_davinci_get_cd(struct mmc_host *mmc)
{
        struct platform_device *pdev = to_platform_device(mmc->parent);
        struct davinci_mmc_config *config = pdev->dev.platform_data;

        if (!config || !config->get_cd)
                return -ENOSYS;
        return config->get_cd(pdev->id);
}

static int mmc_davinci_get_ro(struct mmc_host *mmc)
{
        struct platform_device *pdev = to_platform_device(mmc->parent);
        struct davinci_mmc_config *config = pdev->dev.platform_data;

        if (!config || !config->get_ro)
                return -ENOSYS;
        return config->get_ro(pdev->id);
}

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

        if (enable) {
                if (!(readl(host->base + DAVINCI_SDIOST0) & SDIOST0_DAT1_HI)) {
                        writel(SDIOIST_IOINT, host->base + DAVINCI_SDIOIST);
                        mmc_signal_sdio_irq(host->mmc);
                } else {
                        host->sdio_int = true;
                        writel(readl(host->base + DAVINCI_SDIOIEN) |
                               SDIOIEN_IOINTEN, host->base + DAVINCI_SDIOIEN);
                }
        } else {
                host->sdio_int = false;
                writel(readl(host->base + DAVINCI_SDIOIEN) & ~SDIOIEN_IOINTEN,
                       host->base + DAVINCI_SDIOIEN);
        }
}

static struct mmc_host_ops mmc_davinci_ops = {
        .request        = mmc_davinci_request,
        .set_ios        = mmc_davinci_set_ios,
        .get_cd         = mmc_davinci_get_cd,
        .get_ro         = mmc_davinci_get_ro,
        .enable_sdio_irq = mmc_davinci_enable_sdio_irq,
};

/*----------------------------------------------------------------------*/

#ifdef CONFIG_CPU_FREQ
static int mmc_davinci_cpufreq_transition(struct notifier_block *nb,
                                     unsigned long val, void *data)
{
        struct mmc_davinci_host *host;
        unsigned int mmc_pclk;
        struct mmc_host *mmc;
        unsigned long flags;

        host = container_of(nb, struct mmc_davinci_host, freq_transition);
        mmc = host->mmc;
        mmc_pclk = clk_get_rate(host->clk);

        if (val == CPUFREQ_POSTCHANGE) {
                spin_lock_irqsave(&mmc->lock, flags);
                host->mmc_input_clk = mmc_pclk;
                calculate_clk_divider(mmc, &mmc->ios);
                spin_unlock_irqrestore(&mmc->lock, flags);
        }

        return 0;
}

static inline int mmc_davinci_cpufreq_register(struct mmc_davinci_host *host)
{
        host->freq_transition.notifier_call = mmc_davinci_cpufreq_transition;

        return cpufreq_register_notifier(&host->freq_transition,
                                         CPUFREQ_TRANSITION_NOTIFIER);
}

static inline void mmc_davinci_cpufreq_deregister(struct mmc_davinci_host *host)
{
        cpufreq_unregister_notifier(&host->freq_transition,
                                    CPUFREQ_TRANSITION_NOTIFIER);
}
#else
static inline int mmc_davinci_cpufreq_register(struct mmc_davinci_host *host)
{
        return 0;
}

static inline void mmc_davinci_cpufreq_deregister(struct mmc_davinci_host *host)
{
}
#endif
static void __init init_mmcsd_host(struct mmc_davinci_host *host)
{

        mmc_davinci_reset_ctrl(host, 1);

        writel(0, host->base + DAVINCI_MMCCLK);
        writel(MMCCLK_CLKEN, host->base + DAVINCI_MMCCLK);

        writel(0x1FFF, host->base + DAVINCI_MMCTOR);
        writel(0xFFFF, host->base + DAVINCI_MMCTOD);

        mmc_davinci_reset_ctrl(host, 0);
}

static int __init davinci_mmcsd_probe(struct platform_device *pdev)
{
        struct davinci_mmc_config *pdata = pdev->dev.platform_data;
        struct mmc_davinci_host *host = NULL;
        struct mmc_host *mmc = NULL;
        struct resource *r, *mem = NULL;
        int ret = 0, irq = 0;
        size_t mem_size;

        /* REVISIT:  when we're fully converted, fail if pdata is NULL */

        ret = -ENODEV;
        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        irq = platform_get_irq(pdev, 0);
        if (!r || irq == NO_IRQ)
                goto out;

        ret = -EBUSY;
        mem_size = resource_size(r);
        mem = request_mem_region(r->start, mem_size, pdev->name);
        if (!mem)
                goto out;

        ret = -ENOMEM;
        mmc = mmc_alloc_host(sizeof(struct mmc_davinci_host), &pdev->dev);
        if (!mmc)
                goto out;

        host = mmc_priv(mmc);
        host->mmc = mmc;        /* Important */

        r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
        if (!r)
                goto out;
        host->rxdma = r->start;

        r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
        if (!r)
                goto out;
        host->txdma = r->start;

        host->mem_res = mem;
        host->base = ioremap(mem->start, mem_size);
        if (!host->base)
                goto out;

        ret = -ENXIO;
        host->clk = clk_get(&pdev->dev, "MMCSDCLK");
        if (IS_ERR(host->clk)) {
                ret = PTR_ERR(host->clk);
                goto out;
        }
        clk_enable(host->clk);
        host->mmc_input_clk = clk_get_rate(host->clk);

        init_mmcsd_host(host);

        if (pdata->nr_sg)
                host->nr_sg = pdata->nr_sg - 1;

        if (host->nr_sg > MAX_NR_SG || !host->nr_sg)
                host->nr_sg = MAX_NR_SG;

        host->use_dma = use_dma;
        host->mmc_irq = irq;
        host->sdio_irq = platform_get_irq(pdev, 1);

        if (host->use_dma && davinci_acquire_dma_channels(host) != 0)
                host->use_dma = 0;

        /* REVISIT:  someday, support IRQ-driven card detection.  */
        mmc->caps |= MMC_CAP_NEEDS_POLL;
        mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY;

        if (pdata && (pdata->wires == 4 || pdata->wires == 0))
                mmc->caps |= MMC_CAP_4_BIT_DATA;

        if (pdata && (pdata->wires == 8))
                mmc->caps |= (MMC_CAP_4_BIT_DATA | MMC_CAP_8_BIT_DATA);

        host->version = pdata->version;

        mmc->ops = &mmc_davinci_ops;
        mmc->f_min = 312500;
        mmc->f_max = 25000000;
        if (pdata && pdata->max_freq)
                mmc->f_max = pdata->max_freq;
        if (pdata && pdata->caps)
                mmc->caps |= pdata->caps;
        mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;

        /* With no iommu coalescing pages, each phys_seg is a hw_seg.
         * Each hw_seg uses one EDMA parameter RAM slot, always one
         * channel and then usually some linked slots.
         */
        mmc->max_segs           = 1 + host->n_link;

        /* EDMA limit per hw segment (one or two MBytes) */
        mmc->max_seg_size       = MAX_CCNT * rw_threshold;

        /* MMC/SD controller limits for multiblock requests */
        mmc->max_blk_size       = 4095;  /* BLEN is 12 bits */
        mmc->max_blk_count      = 65535; /* NBLK is 16 bits */
        mmc->max_req_size       = mmc->max_blk_size * mmc->max_blk_count;

        dev_dbg(mmc_dev(host->mmc), "max_segs=%d\n", mmc->max_segs);
        dev_dbg(mmc_dev(host->mmc), "max_blk_size=%d\n", mmc->max_blk_size);
        dev_dbg(mmc_dev(host->mmc), "max_req_size=%d\n", mmc->max_req_size);
        dev_dbg(mmc_dev(host->mmc), "max_seg_size=%d\n", mmc->max_seg_size);

        platform_set_drvdata(pdev, host);

        ret = mmc_davinci_cpufreq_register(host);
        if (ret) {
                dev_err(&pdev->dev, "failed to register cpufreq\n");
                goto cpu_freq_fail;
        }

        ret = mmc_add_host(mmc);
        if (ret < 0)
                goto out;

        ret = request_irq(irq, mmc_davinci_irq, 0, mmc_hostname(mmc), host);
        if (ret)
                goto out;

        if (host->sdio_irq >= 0) {
                ret = request_irq(host->sdio_irq, mmc_davinci_sdio_irq, 0,
                                  mmc_hostname(mmc), host);
                if (!ret)
                        mmc->caps |= MMC_CAP_SDIO_IRQ;
        }

        rename_region(mem, mmc_hostname(mmc));

        dev_info(mmc_dev(host->mmc), "Using %s, %d-bit mode\n",
                host->use_dma ? "DMA" : "PIO",
                (mmc->caps & MMC_CAP_4_BIT_DATA) ? 4 : 1);

        return 0;

out:
        mmc_davinci_cpufreq_deregister(host);
cpu_freq_fail:
        if (host) {
                davinci_release_dma_channels(host);

                if (host->clk) {
                        clk_disable(host->clk);
                        clk_put(host->clk);
                }

                if (host->base)
                        iounmap(host->base);
        }

        if (mmc)
                mmc_free_host(mmc);

        if (mem)
                release_resource(mem);

        dev_dbg(&pdev->dev, "probe err %d\n", ret);

        return ret;
}

static int __exit davinci_mmcsd_remove(struct platform_device *pdev)
{
        struct mmc_davinci_host *host = platform_get_drvdata(pdev);

        platform_set_drvdata(pdev, NULL);
        if (host) {
                mmc_davinci_cpufreq_deregister(host);

                mmc_remove_host(host->mmc);
                free_irq(host->mmc_irq, host);
                if (host->mmc->caps & MMC_CAP_SDIO_IRQ)
                        free_irq(host->sdio_irq, host);

                davinci_release_dma_channels(host);

                clk_disable(host->clk);
                clk_put(host->clk);

                iounmap(host->base);

                release_resource(host->mem_res);

                mmc_free_host(host->mmc);
        }

        return 0;
}

#ifdef CONFIG_PM
static int davinci_mmcsd_suspend(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct mmc_davinci_host *host = platform_get_drvdata(pdev);
        int ret;

        ret = mmc_suspend_host(host->mmc);
        if (!ret) {
                writel(0, host->base + DAVINCI_MMCIM);
                mmc_davinci_reset_ctrl(host, 1);
                clk_disable(host->clk);
                host->suspended = 1;
        } else {
                host->suspended = 0;
        }

        return ret;
}

static int davinci_mmcsd_resume(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct mmc_davinci_host *host = platform_get_drvdata(pdev);
        int ret;

        if (!host->suspended)
                return 0;

        clk_enable(host->clk);

        mmc_davinci_reset_ctrl(host, 0);
        ret = mmc_resume_host(host->mmc);
        if (!ret)
                host->suspended = 0;

        return ret;
}

static const struct dev_pm_ops davinci_mmcsd_pm = {
        .suspend        = davinci_mmcsd_suspend,
        .resume         = davinci_mmcsd_resume,
};

#define davinci_mmcsd_pm_ops (&davinci_mmcsd_pm)
#else
#define davinci_mmcsd_pm_ops NULL
#endif

static struct platform_driver davinci_mmcsd_driver = {
        .driver         = {
                .name   = "davinci_mmc",
                .owner  = THIS_MODULE,
                .pm     = davinci_mmcsd_pm_ops,
        },
        .remove         = __exit_p(davinci_mmcsd_remove),
};

static int __init davinci_mmcsd_init(void)
{
        return platform_driver_probe(&davinci_mmcsd_driver,
                                     davinci_mmcsd_probe);
}
module_init(davinci_mmcsd_init);

static void __exit davinci_mmcsd_exit(void)
{
        platform_driver_unregister(&davinci_mmcsd_driver);
}
module_exit(davinci_mmcsd_exit);

MODULE_AUTHOR("Texas Instruments India");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("MMC/SD driver for Davinci MMC controller");
MODULE_ALIAS("platform:davinci_mmc");