/*
 * drivers/ata/pata_arasan_cf.c
 *
 * Arasan Compact Flash host controller source file
 *
 * Copyright (C) 2011 ST Microelectronics
 * Viresh Kumar <vireshk@kernel.org>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

/*
 * The Arasan CompactFlash Device Controller IP core has three basic modes of
 * operation: PC card ATA using I/O mode, PC card ATA using memory mode, PC card
 * ATA using true IDE modes. This driver supports only True IDE mode currently.
 *
 * Arasan CF Controller shares global irq register with Arasan XD Controller.
 *
 * Tested on arch/arm/mach-spear13xx
 */

#include <linux/ata.h>
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/libata.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/pata_arasan_cf_data.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/workqueue.h>

#define DRIVER_NAME     "arasan_cf"
#define TIMEOUT         msecs_to_jiffies(3000)

/* Registers */
/* CompactFlash Interface Status */
#define CFI_STS                 0x000
        #define STS_CHG                         (1)
        #define BIN_AUDIO_OUT                   (1 << 1)
        #define CARD_DETECT1                    (1 << 2)
        #define CARD_DETECT2                    (1 << 3)
        #define INP_ACK                         (1 << 4)
        #define CARD_READY                      (1 << 5)
        #define IO_READY                        (1 << 6)
        #define B16_IO_PORT_SEL                 (1 << 7)
/* IRQ */
#define IRQ_STS                 0x004
/* Interrupt Enable */
#define IRQ_EN                  0x008
        #define CARD_DETECT_IRQ                 (1)
        #define STATUS_CHNG_IRQ                 (1 << 1)
        #define MEM_MODE_IRQ                    (1 << 2)
        #define IO_MODE_IRQ                     (1 << 3)
        #define TRUE_IDE_MODE_IRQ               (1 << 8)
        #define PIO_XFER_ERR_IRQ                (1 << 9)
        #define BUF_AVAIL_IRQ                   (1 << 10)
        #define XFER_DONE_IRQ                   (1 << 11)
        #define IGNORED_IRQS    (STATUS_CHNG_IRQ | MEM_MODE_IRQ | IO_MODE_IRQ |\
                                        TRUE_IDE_MODE_IRQ)
        #define TRUE_IDE_IRQS   (CARD_DETECT_IRQ | PIO_XFER_ERR_IRQ |\
                                        BUF_AVAIL_IRQ | XFER_DONE_IRQ)
/* Operation Mode */
#define OP_MODE                 0x00C
        #define CARD_MODE_MASK                  (0x3)
        #define MEM_MODE                        (0x0)
        #define IO_MODE                         (0x1)
        #define TRUE_IDE_MODE                   (0x2)

        #define CARD_TYPE_MASK                  (1 << 2)
        #define CF_CARD                         (0)
        #define CF_PLUS_CARD                    (1 << 2)

        #define CARD_RESET                      (1 << 3)
        #define CFHOST_ENB                      (1 << 4)
        #define OUTPUTS_TRISTATE                (1 << 5)
        #define ULTRA_DMA_ENB                   (1 << 8)
        #define MULTI_WORD_DMA_ENB              (1 << 9)
        #define DRQ_BLOCK_SIZE_MASK             (0x3 << 11)
        #define DRQ_BLOCK_SIZE_512              (0)
        #define DRQ_BLOCK_SIZE_1024             (1 << 11)
        #define DRQ_BLOCK_SIZE_2048             (2 << 11)
        #define DRQ_BLOCK_SIZE_4096             (3 << 11)
/* CF Interface Clock Configuration */
#define CLK_CFG                 0x010
        #define CF_IF_CLK_MASK                  (0XF)
/* CF Timing Mode Configuration */
#define TM_CFG                  0x014
        #define MEM_MODE_TIMING_MASK            (0x3)
        #define MEM_MODE_TIMING_250NS           (0x0)
        #define MEM_MODE_TIMING_120NS           (0x1)
        #define MEM_MODE_TIMING_100NS           (0x2)
        #define MEM_MODE_TIMING_80NS            (0x3)

        #define IO_MODE_TIMING_MASK             (0x3 << 2)
        #define IO_MODE_TIMING_250NS            (0x0 << 2)
        #define IO_MODE_TIMING_120NS            (0x1 << 2)
        #define IO_MODE_TIMING_100NS            (0x2 << 2)
        #define IO_MODE_TIMING_80NS             (0x3 << 2)

        #define TRUEIDE_PIO_TIMING_MASK         (0x7 << 4)
        #define TRUEIDE_PIO_TIMING_SHIFT        4

        #define TRUEIDE_MWORD_DMA_TIMING_MASK   (0x7 << 7)
        #define TRUEIDE_MWORD_DMA_TIMING_SHIFT  7

        #define ULTRA_DMA_TIMING_MASK           (0x7 << 10)
        #define ULTRA_DMA_TIMING_SHIFT          10
/* CF Transfer Address */
#define XFER_ADDR               0x014
        #define XFER_ADDR_MASK                  (0x7FF)
        #define MAX_XFER_COUNT                  0x20000u
/* Transfer Control */
#define XFER_CTR                0x01C
        #define XFER_COUNT_MASK                 (0x3FFFF)
        #define ADDR_INC_DISABLE                (1 << 24)
        #define XFER_WIDTH_MASK                 (1 << 25)
        #define XFER_WIDTH_8B                   (0)
        #define XFER_WIDTH_16B                  (1 << 25)

        #define MEM_TYPE_MASK                   (1 << 26)
        #define MEM_TYPE_COMMON                 (0)
        #define MEM_TYPE_ATTRIBUTE              (1 << 26)

        #define MEM_IO_XFER_MASK                (1 << 27)
        #define MEM_XFER                        (0)
        #define IO_XFER                         (1 << 27)

        #define DMA_XFER_MODE                   (1 << 28)

        #define AHB_BUS_NORMAL_PIO_OPRTN        (~(1 << 29))
        #define XFER_DIR_MASK                   (1 << 30)
        #define XFER_READ                       (0)
        #define XFER_WRITE                      (1 << 30)

        #define XFER_START                      (1 << 31)
/* Write Data Port */
#define WRITE_PORT              0x024
/* Read Data Port */
#define READ_PORT               0x028
/* ATA Data Port */
#define ATA_DATA_PORT           0x030
        #define ATA_DATA_PORT_MASK              (0xFFFF)
/* ATA Error/Features */
#define ATA_ERR_FTR             0x034
/* ATA Sector Count */
#define ATA_SC                  0x038
/* ATA Sector Number */
#define ATA_SN                  0x03C
/* ATA Cylinder Low */
#define ATA_CL                  0x040
/* ATA Cylinder High */
#define ATA_CH                  0x044
/* ATA Select Card/Head */
#define ATA_SH                  0x048
/* ATA Status-Command */
#define ATA_STS_CMD             0x04C
/* ATA Alternate Status/Device Control */
#define ATA_ASTS_DCTR           0x050
/* Extended Write Data Port 0x200-0x3FC */
#define EXT_WRITE_PORT          0x200
/* Extended Read Data Port 0x400-0x5FC */
#define EXT_READ_PORT           0x400
        #define FIFO_SIZE       0x200u
/* Global Interrupt Status */
#define GIRQ_STS                0x800
/* Global Interrupt Status enable */
#define GIRQ_STS_EN             0x804
/* Global Interrupt Signal enable */
#define GIRQ_SGN_EN             0x808
        #define GIRQ_CF         (1)
        #define GIRQ_XD         (1 << 1)

/* Compact Flash Controller Dev Structure */
struct arasan_cf_dev {
        /* pointer to ata_host structure */
        struct ata_host *host;
        /* clk structure */
        struct clk *clk;

        /* physical base address of controller */
        dma_addr_t pbase;
        /* virtual base address of controller */
        void __iomem *vbase;
        /* irq number*/
        int irq;

        /* status to be updated to framework regarding DMA transfer */
        u8 dma_status;
        /* Card is present or Not */
        u8 card_present;

        /* dma specific */
        /* Completion for transfer complete interrupt from controller */
        struct completion cf_completion;
        /* Completion for DMA transfer complete. */
        struct completion dma_completion;
        /* Dma channel allocated */
        struct dma_chan *dma_chan;
        /* Mask for DMA transfers */
        dma_cap_mask_t mask;
        /* DMA transfer work */
        struct work_struct work;
        /* DMA delayed finish work */
        struct delayed_work dwork;
        /* qc to be transferred using DMA */
        struct ata_queued_cmd *qc;
};

static struct scsi_host_template arasan_cf_sht = {
        ATA_BASE_SHT(DRIVER_NAME),
        .dma_boundary = 0xFFFFFFFFUL,
};

static void cf_dumpregs(struct arasan_cf_dev *acdev)
{
        struct device *dev = acdev->host->dev;

        dev_dbg(dev, ": =========== REGISTER DUMP ===========");
        dev_dbg(dev, ": CFI_STS: %x", readl(acdev->vbase + CFI_STS));
        dev_dbg(dev, ": IRQ_STS: %x", readl(acdev->vbase + IRQ_STS));
        dev_dbg(dev, ": IRQ_EN: %x", readl(acdev->vbase + IRQ_EN));
        dev_dbg(dev, ": OP_MODE: %x", readl(acdev->vbase + OP_MODE));
        dev_dbg(dev, ": CLK_CFG: %x", readl(acdev->vbase + CLK_CFG));
        dev_dbg(dev, ": TM_CFG: %x", readl(acdev->vbase + TM_CFG));
        dev_dbg(dev, ": XFER_CTR: %x", readl(acdev->vbase + XFER_CTR));
        dev_dbg(dev, ": GIRQ_STS: %x", readl(acdev->vbase + GIRQ_STS));
        dev_dbg(dev, ": GIRQ_STS_EN: %x", readl(acdev->vbase + GIRQ_STS_EN));
        dev_dbg(dev, ": GIRQ_SGN_EN: %x", readl(acdev->vbase + GIRQ_SGN_EN));
        dev_dbg(dev, ": =====================================");
}

/* Enable/Disable global interrupts shared between CF and XD ctrlr. */
static void cf_ginterrupt_enable(struct arasan_cf_dev *acdev, bool enable)
{
        /* enable should be 0 or 1 */
        writel(enable, acdev->vbase + GIRQ_STS_EN);
        writel(enable, acdev->vbase + GIRQ_SGN_EN);
}

/* Enable/Disable CF interrupts */
static inline void
cf_interrupt_enable(struct arasan_cf_dev *acdev, u32 mask, bool enable)
{
        u32 val = readl(acdev->vbase + IRQ_EN);
        /* clear & enable/disable irqs */
        if (enable) {
                writel(mask, acdev->vbase + IRQ_STS);
                writel(val | mask, acdev->vbase + IRQ_EN);
        } else
                writel(val & ~mask, acdev->vbase + IRQ_EN);
}

static inline void cf_card_reset(struct arasan_cf_dev *acdev)
{
        u32 val = readl(acdev->vbase + OP_MODE);

        writel(val | CARD_RESET, acdev->vbase + OP_MODE);
        udelay(200);
        writel(val & ~CARD_RESET, acdev->vbase + OP_MODE);
}

static inline void cf_ctrl_reset(struct arasan_cf_dev *acdev)
{
        writel(readl(acdev->vbase + OP_MODE) & ~CFHOST_ENB,
                        acdev->vbase + OP_MODE);
        writel(readl(acdev->vbase + OP_MODE) | CFHOST_ENB,
                        acdev->vbase + OP_MODE);
}

static void cf_card_detect(struct arasan_cf_dev *acdev, bool hotplugged)
{
        struct ata_port *ap = acdev->host->ports[0];
        struct ata_eh_info *ehi = &ap->link.eh_info;
        u32 val = readl(acdev->vbase + CFI_STS);

        /* Both CD1 & CD2 should be low if card inserted completely */
        if (!(val & (CARD_DETECT1 | CARD_DETECT2))) {
                if (acdev->card_present)
                        return;
                acdev->card_present = 1;
                cf_card_reset(acdev);
        } else {
                if (!acdev->card_present)
                        return;
                acdev->card_present = 0;
        }

        if (hotplugged) {
                ata_ehi_hotplugged(ehi);
                ata_port_freeze(ap);
        }
}

static int cf_init(struct arasan_cf_dev *acdev)
{
        struct arasan_cf_pdata *pdata = dev_get_platdata(acdev->host->dev);
        unsigned int if_clk;
        unsigned long flags;
        int ret = 0;

        ret = clk_prepare_enable(acdev->clk);
        if (ret) {
                dev_dbg(acdev->host->dev, "clock enable failed");
                return ret;
        }

        ret = clk_set_rate(acdev->clk, 166000000);
        if (ret) {
                dev_warn(acdev->host->dev, "clock set rate failed");
                clk_disable_unprepare(acdev->clk);
                return ret;
        }

        spin_lock_irqsave(&acdev->host->lock, flags);
        /* configure CF interface clock */
        /* TODO: read from device tree */
        if_clk = CF_IF_CLK_166M;
        if (pdata && pdata->cf_if_clk <= CF_IF_CLK_200M)
                if_clk = pdata->cf_if_clk;

        writel(if_clk, acdev->vbase + CLK_CFG);

        writel(TRUE_IDE_MODE | CFHOST_ENB, acdev->vbase + OP_MODE);
        cf_interrupt_enable(acdev, CARD_DETECT_IRQ, 1);
        cf_ginterrupt_enable(acdev, 1);
        spin_unlock_irqrestore(&acdev->host->lock, flags);

        return ret;
}

static void cf_exit(struct arasan_cf_dev *acdev)
{
        unsigned long flags;

        spin_lock_irqsave(&acdev->host->lock, flags);
        cf_ginterrupt_enable(acdev, 0);
        cf_interrupt_enable(acdev, TRUE_IDE_IRQS, 0);
        cf_card_reset(acdev);
        writel(readl(acdev->vbase + OP_MODE) & ~CFHOST_ENB,
                        acdev->vbase + OP_MODE);
        spin_unlock_irqrestore(&acdev->host->lock, flags);
        clk_disable_unprepare(acdev->clk);
}

static void dma_callback(void *dev)
{
        struct arasan_cf_dev *acdev = dev;

        complete(&acdev->dma_completion);
}

static inline void dma_complete(struct arasan_cf_dev *acdev)
{
        struct ata_queued_cmd *qc = acdev->qc;
        unsigned long flags;

        acdev->qc = NULL;
        ata_sff_interrupt(acdev->irq, acdev->host);

        spin_lock_irqsave(&acdev->host->lock, flags);
        if (unlikely(qc->err_mask) && ata_is_dma(qc->tf.protocol))
                ata_ehi_push_desc(&qc->ap->link.eh_info, "DMA Failed: Timeout");
        spin_unlock_irqrestore(&acdev->host->lock, flags);
}

static inline int wait4buf(struct arasan_cf_dev *acdev)
{
        if (!wait_for_completion_timeout(&acdev->cf_completion, TIMEOUT)) {
                u32 rw = acdev->qc->tf.flags & ATA_TFLAG_WRITE;

                dev_err(acdev->host->dev, "%s TimeOut", rw ? "write" : "read");
                return -ETIMEDOUT;
        }

        /* Check if PIO Error interrupt has occurred */
        if (acdev->dma_status & ATA_DMA_ERR)
                return -EAGAIN;

        return 0;
}

static int
dma_xfer(struct arasan_cf_dev *acdev, dma_addr_t src, dma_addr_t dest, u32 len)
{
        struct dma_async_tx_descriptor *tx;
        struct dma_chan *chan = acdev->dma_chan;
        dma_cookie_t cookie;
        unsigned long flags = DMA_PREP_INTERRUPT;
        int ret = 0;

        tx = chan->device->device_prep_dma_memcpy(chan, dest, src, len, flags);
        if (!tx) {
                dev_err(acdev->host->dev, "device_prep_dma_memcpy failed\n");
                return -EAGAIN;
        }

        tx->callback = dma_callback;
        tx->callback_param = acdev;
        cookie = tx->tx_submit(tx);

        ret = dma_submit_error(cookie);
        if (ret) {
                dev_err(acdev->host->dev, "dma_submit_error\n");
                return ret;
        }

        chan->device->device_issue_pending(chan);

        /* Wait for DMA to complete */
        if (!wait_for_completion_timeout(&acdev->dma_completion, TIMEOUT)) {
                dmaengine_terminate_all(chan);
                dev_err(acdev->host->dev, "wait_for_completion_timeout\n");
                return -ETIMEDOUT;
        }

        return ret;
}

static int sg_xfer(struct arasan_cf_dev *acdev, struct scatterlist *sg)
{
        dma_addr_t dest = 0, src = 0;
        u32 xfer_cnt, sglen, dma_len, xfer_ctr;
        u32 write = acdev->qc->tf.flags & ATA_TFLAG_WRITE;
        unsigned long flags;
        int ret = 0;

        sglen = sg_dma_len(sg);
        if (write) {
                src = sg_dma_address(sg);
                dest = acdev->pbase + EXT_WRITE_PORT;
        } else {
                dest = sg_dma_address(sg);
                src = acdev->pbase + EXT_READ_PORT;
        }

        /*
         * For each sg:
         * MAX_XFER_COUNT data will be transferred before we get transfer
         * complete interrupt. Between after FIFO_SIZE data
         * buffer available interrupt will be generated. At this time we will
         * fill FIFO again: max FIFO_SIZE data.
         */
        while (sglen) {
                xfer_cnt = min(sglen, MAX_XFER_COUNT);
                spin_lock_irqsave(&acdev->host->lock, flags);
                xfer_ctr = readl(acdev->vbase + XFER_CTR) &
                        ~XFER_COUNT_MASK;
                writel(xfer_ctr | xfer_cnt | XFER_START,
                                acdev->vbase + XFER_CTR);
                spin_unlock_irqrestore(&acdev->host->lock, flags);

                /* continue dma xfers until current sg is completed */
                while (xfer_cnt) {
                        /* wait for read to complete */
                        if (!write) {
                                ret = wait4buf(acdev);
                                if (ret)
                                        goto fail;
                        }

                        /* read/write FIFO in chunk of FIFO_SIZE */
                        dma_len = min(xfer_cnt, FIFO_SIZE);
                        ret = dma_xfer(acdev, src, dest, dma_len);
                        if (ret) {
                                dev_err(acdev->host->dev, "dma failed");
                                goto fail;
                        }

                        if (write)
                                src += dma_len;
                        else
                                dest += dma_len;

                        sglen -= dma_len;
                        xfer_cnt -= dma_len;

                        /* wait for write to complete */
                        if (write) {
                                ret = wait4buf(acdev);
                                if (ret)
                                        goto fail;
                        }
                }
        }

fail:
        spin_lock_irqsave(&acdev->host->lock, flags);
        writel(readl(acdev->vbase + XFER_CTR) & ~XFER_START,
                        acdev->vbase + XFER_CTR);
        spin_unlock_irqrestore(&acdev->host->lock, flags);

        return ret;
}

/*
 * This routine uses External DMA controller to read/write data to FIFO of CF
 * controller. There are two xfer related interrupt supported by CF controller:
 * - buf_avail: This interrupt is generated as soon as we have buffer of 512
 *      bytes available for reading or empty buffer available for writing.
 * - xfer_done: This interrupt is generated on transfer of "xfer_size" amount of
 *      data to/from FIFO. xfer_size is programmed in XFER_CTR register.
 *
 * Max buffer size = FIFO_SIZE = 512 Bytes.
 * Max xfer_size = MAX_XFER_COUNT = 256 KB.
 */
static void data_xfer(struct work_struct *work)
{
        struct arasan_cf_dev *acdev = container_of(work, struct arasan_cf_dev,
                        work);
        struct ata_queued_cmd *qc = acdev->qc;
        struct scatterlist *sg;
        unsigned long flags;
        u32 temp;
        int ret = 0;

        /* request dma channels */
        /* dma_request_channel may sleep, so calling from process context */
        acdev->dma_chan = dma_request_chan(acdev->host->dev, "data");
        if (IS_ERR(acdev->dma_chan)) {
                dev_err(acdev->host->dev, "Unable to get dma_chan\n");
                acdev->dma_chan = NULL;
                goto chan_request_fail;
        }

        for_each_sg(qc->sg, sg, qc->n_elem, temp) {
                ret = sg_xfer(acdev, sg);
                if (ret)
                        break;
        }

        dma_release_channel(acdev->dma_chan);
        acdev->dma_chan = NULL;

        /* data xferred successfully */
        if (!ret) {
                u32 status;

                spin_lock_irqsave(&acdev->host->lock, flags);
                status = ioread8(qc->ap->ioaddr.altstatus_addr);
                spin_unlock_irqrestore(&acdev->host->lock, flags);
                if (status & (ATA_BUSY | ATA_DRQ)) {
                        ata_sff_queue_delayed_work(&acdev->dwork, 1);
                        return;
                }

                goto sff_intr;
        }

        cf_dumpregs(acdev);

chan_request_fail:
        spin_lock_irqsave(&acdev->host->lock, flags);
        /* error when transferring data to/from memory */
        qc->err_mask |= AC_ERR_HOST_BUS;
        qc->ap->hsm_task_state = HSM_ST_ERR;

        cf_ctrl_reset(acdev);
        spin_unlock_irqrestore(&acdev->host->lock, flags);
sff_intr:
        dma_complete(acdev);
}

static void delayed_finish(struct work_struct *work)
{
        struct arasan_cf_dev *acdev = container_of(work, struct arasan_cf_dev,
                        dwork.work);
        struct ata_queued_cmd *qc = acdev->qc;
        unsigned long flags;
        u8 status;

        spin_lock_irqsave(&acdev->host->lock, flags);
        status = ioread8(qc->ap->ioaddr.altstatus_addr);
        spin_unlock_irqrestore(&acdev->host->lock, flags);

        if (status & (ATA_BUSY | ATA_DRQ))
                ata_sff_queue_delayed_work(&acdev->dwork, 1);
        else
                dma_complete(acdev);
}

static irqreturn_t arasan_cf_interrupt(int irq, void *dev)
{
        struct arasan_cf_dev *acdev = ((struct ata_host *)dev)->private_data;
        unsigned long flags;
        u32 irqsts;

        irqsts = readl(acdev->vbase + GIRQ_STS);
        if (!(irqsts & GIRQ_CF))
                return IRQ_NONE;

        spin_lock_irqsave(&acdev->host->lock, flags);
        irqsts = readl(acdev->vbase + IRQ_STS);
        writel(irqsts, acdev->vbase + IRQ_STS);         /* clear irqs */
        writel(GIRQ_CF, acdev->vbase + GIRQ_STS);       /* clear girqs */

        /* handle only relevant interrupts */
        irqsts &= ~IGNORED_IRQS;

        if (irqsts & CARD_DETECT_IRQ) {
                cf_card_detect(acdev, 1);
                spin_unlock_irqrestore(&acdev->host->lock, flags);
                return IRQ_HANDLED;
        }

        if (irqsts & PIO_XFER_ERR_IRQ) {
                acdev->dma_status = ATA_DMA_ERR;
                writel(readl(acdev->vbase + XFER_CTR) & ~XFER_START,
                                acdev->vbase + XFER_CTR);
                spin_unlock_irqrestore(&acdev->host->lock, flags);
                complete(&acdev->cf_completion);
                dev_err(acdev->host->dev, "pio xfer err irq\n");
                return IRQ_HANDLED;
        }

        spin_unlock_irqrestore(&acdev->host->lock, flags);

        if (irqsts & BUF_AVAIL_IRQ) {
                complete(&acdev->cf_completion);
                return IRQ_HANDLED;
        }

        if (irqsts & XFER_DONE_IRQ) {
                struct ata_queued_cmd *qc = acdev->qc;

                /* Send Complete only for write */
                if (qc->tf.flags & ATA_TFLAG_WRITE)
                        complete(&acdev->cf_completion);
        }

        return IRQ_HANDLED;
}

static void arasan_cf_freeze(struct ata_port *ap)
{
        struct arasan_cf_dev *acdev = ap->host->private_data;

        /* stop transfer and reset controller */
        writel(readl(acdev->vbase + XFER_CTR) & ~XFER_START,
                        acdev->vbase + XFER_CTR);
        cf_ctrl_reset(acdev);
        acdev->dma_status = ATA_DMA_ERR;

        ata_sff_dma_pause(ap);
        ata_sff_freeze(ap);
}

static void arasan_cf_error_handler(struct ata_port *ap)
{
        struct arasan_cf_dev *acdev = ap->host->private_data;

        /*
         * DMA transfers using an external DMA controller may be scheduled.
         * Abort them before handling error. Refer data_xfer() for further
         * details.
         */
        cancel_work_sync(&acdev->work);
        cancel_delayed_work_sync(&acdev->dwork);
        return ata_sff_error_handler(ap);
}

static void arasan_cf_dma_start(struct arasan_cf_dev *acdev)
{
        struct ata_queued_cmd *qc = acdev->qc;
        struct ata_port *ap = qc->ap;
        struct ata_taskfile *tf = &qc->tf;
        u32 xfer_ctr = readl(acdev->vbase + XFER_CTR) & ~XFER_DIR_MASK;
        u32 write = tf->flags & ATA_TFLAG_WRITE;

        xfer_ctr |= write ? XFER_WRITE : XFER_READ;
        writel(xfer_ctr, acdev->vbase + XFER_CTR);

        ap->ops->sff_exec_command(ap, tf);
        ata_sff_queue_work(&acdev->work);
}

static unsigned int arasan_cf_qc_issue(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        struct arasan_cf_dev *acdev = ap->host->private_data;

        /* defer PIO handling to sff_qc_issue */
        if (!ata_is_dma(qc->tf.protocol))
                return ata_sff_qc_issue(qc);

        /* select the device */
        ata_wait_idle(ap);
        ata_sff_dev_select(ap, qc->dev->devno);
        ata_wait_idle(ap);

        /* start the command */
        switch (qc->tf.protocol) {
        case ATA_PROT_DMA:
                WARN_ON_ONCE(qc->tf.flags & ATA_TFLAG_POLLING);

                ap->ops->sff_tf_load(ap, &qc->tf);
                acdev->dma_status = 0;
                acdev->qc = qc;
                arasan_cf_dma_start(acdev);
                ap->hsm_task_state = HSM_ST_LAST;
                break;

        default:
                WARN_ON(1);
                return AC_ERR_SYSTEM;
        }

        return 0;
}

static void arasan_cf_set_piomode(struct ata_port *ap, struct ata_device *adev)
{
        struct arasan_cf_dev *acdev = ap->host->private_data;
        u8 pio = adev->pio_mode - XFER_PIO_0;
        unsigned long flags;
        u32 val;

        /* Arasan ctrl supports Mode0 -> Mode6 */
        if (pio > 6) {
                dev_err(ap->dev, "Unknown PIO mode\n");
                return;
        }

        spin_lock_irqsave(&acdev->host->lock, flags);
        val = readl(acdev->vbase + OP_MODE) &
                ~(ULTRA_DMA_ENB | MULTI_WORD_DMA_ENB | DRQ_BLOCK_SIZE_MASK);
        writel(val, acdev->vbase + OP_MODE);
        val = readl(acdev->vbase + TM_CFG) & ~TRUEIDE_PIO_TIMING_MASK;
        val |= pio << TRUEIDE_PIO_TIMING_SHIFT;
        writel(val, acdev->vbase + TM_CFG);

        cf_interrupt_enable(acdev, BUF_AVAIL_IRQ | XFER_DONE_IRQ, 0);
        cf_interrupt_enable(acdev, PIO_XFER_ERR_IRQ, 1);
        spin_unlock_irqrestore(&acdev->host->lock, flags);
}

static void arasan_cf_set_dmamode(struct ata_port *ap, struct ata_device *adev)
{
        struct arasan_cf_dev *acdev = ap->host->private_data;
        u32 opmode, tmcfg, dma_mode = adev->dma_mode;
        unsigned long flags;

        spin_lock_irqsave(&acdev->host->lock, flags);
        opmode = readl(acdev->vbase + OP_MODE) &
                ~(MULTI_WORD_DMA_ENB | ULTRA_DMA_ENB);
        tmcfg = readl(acdev->vbase + TM_CFG);

        if ((dma_mode >= XFER_UDMA_0) && (dma_mode <= XFER_UDMA_6)) {
                opmode |= ULTRA_DMA_ENB;
                tmcfg &= ~ULTRA_DMA_TIMING_MASK;
                tmcfg |= (dma_mode - XFER_UDMA_0) << ULTRA_DMA_TIMING_SHIFT;
        } else if ((dma_mode >= XFER_MW_DMA_0) && (dma_mode <= XFER_MW_DMA_4)) {
                opmode |= MULTI_WORD_DMA_ENB;
                tmcfg &= ~TRUEIDE_MWORD_DMA_TIMING_MASK;
                tmcfg |= (dma_mode - XFER_MW_DMA_0) <<
                        TRUEIDE_MWORD_DMA_TIMING_SHIFT;
        } else {
                dev_err(ap->dev, "Unknown DMA mode\n");
                spin_unlock_irqrestore(&acdev->host->lock, flags);
                return;
        }

        writel(opmode, acdev->vbase + OP_MODE);
        writel(tmcfg, acdev->vbase + TM_CFG);
        writel(DMA_XFER_MODE, acdev->vbase + XFER_CTR);

        cf_interrupt_enable(acdev, PIO_XFER_ERR_IRQ, 0);
        cf_interrupt_enable(acdev, BUF_AVAIL_IRQ | XFER_DONE_IRQ, 1);
        spin_unlock_irqrestore(&acdev->host->lock, flags);
}

static struct ata_port_operations arasan_cf_ops = {
        .inherits = &ata_sff_port_ops,
        .freeze = arasan_cf_freeze,
        .error_handler = arasan_cf_error_handler,
        .qc_issue = arasan_cf_qc_issue,
        .set_piomode = arasan_cf_set_piomode,
        .set_dmamode = arasan_cf_set_dmamode,
};

static int arasan_cf_probe(struct platform_device *pdev)
{
        struct arasan_cf_dev *acdev;
        struct arasan_cf_pdata *pdata = dev_get_platdata(&pdev->dev);
        struct ata_host *host;
        struct ata_port *ap;
        struct resource *res;
        u32 quirk;
        irq_handler_t irq_handler = NULL;
        int ret;

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

        if (!devm_request_mem_region(&pdev->dev, res->start, resource_size(res),
                                DRIVER_NAME)) {
                dev_warn(&pdev->dev, "Failed to get memory region resource\n");
                return -ENOENT;
        }

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

        if (pdata)
                quirk = pdata->quirk;
        else
                quirk = CF_BROKEN_UDMA; /* as it is on spear1340 */

        /* if irq is 0, support only PIO */
        acdev->irq = platform_get_irq(pdev, 0);
        if (acdev->irq)
                irq_handler = arasan_cf_interrupt;
        else
                quirk |= CF_BROKEN_MWDMA | CF_BROKEN_UDMA;

        acdev->pbase = res->start;
        acdev->vbase = devm_ioremap(&pdev->dev, res->start,
                        resource_size(res));
        if (!acdev->vbase) {
                dev_warn(&pdev->dev, "ioremap fail\n");
                return -ENOMEM;
        }

        acdev->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(acdev->clk)) {
                dev_warn(&pdev->dev, "Clock not found\n");
                return PTR_ERR(acdev->clk);
        }

        /* allocate host */
        host = ata_host_alloc(&pdev->dev, 1);
        if (!host) {
                dev_warn(&pdev->dev, "alloc host fail\n");
                return -ENOMEM;
        }

        ap = host->ports[0];
        host->private_data = acdev;
        acdev->host = host;
        ap->ops = &arasan_cf_ops;
        ap->pio_mask = ATA_PIO6;
        ap->mwdma_mask = ATA_MWDMA4;
        ap->udma_mask = ATA_UDMA6;

        init_completion(&acdev->cf_completion);
        init_completion(&acdev->dma_completion);
        INIT_WORK(&acdev->work, data_xfer);
        INIT_DELAYED_WORK(&acdev->dwork, delayed_finish);
        dma_cap_set(DMA_MEMCPY, acdev->mask);

        /* Handle platform specific quirks */
        if (quirk) {
                if (quirk & CF_BROKEN_PIO) {
                        ap->ops->set_piomode = NULL;
                        ap->pio_mask = 0;
                }
                if (quirk & CF_BROKEN_MWDMA)
                        ap->mwdma_mask = 0;
                if (quirk & CF_BROKEN_UDMA)
                        ap->udma_mask = 0;
        }
        ap->flags |= ATA_FLAG_PIO_POLLING | ATA_FLAG_NO_ATAPI;

        ap->ioaddr.cmd_addr = acdev->vbase + ATA_DATA_PORT;
        ap->ioaddr.data_addr = acdev->vbase + ATA_DATA_PORT;
        ap->ioaddr.error_addr = acdev->vbase + ATA_ERR_FTR;
        ap->ioaddr.feature_addr = acdev->vbase + ATA_ERR_FTR;
        ap->ioaddr.nsect_addr = acdev->vbase + ATA_SC;
        ap->ioaddr.lbal_addr = acdev->vbase + ATA_SN;
        ap->ioaddr.lbam_addr = acdev->vbase + ATA_CL;
        ap->ioaddr.lbah_addr = acdev->vbase + ATA_CH;
        ap->ioaddr.device_addr = acdev->vbase + ATA_SH;
        ap->ioaddr.status_addr = acdev->vbase + ATA_STS_CMD;
        ap->ioaddr.command_addr = acdev->vbase + ATA_STS_CMD;
        ap->ioaddr.altstatus_addr = acdev->vbase + ATA_ASTS_DCTR;
        ap->ioaddr.ctl_addr = acdev->vbase + ATA_ASTS_DCTR;

        ata_port_desc(ap, "phy_addr %llx virt_addr %p",
                      (unsigned long long) res->start, acdev->vbase);

        ret = cf_init(acdev);
        if (ret)
                return ret;

        cf_card_detect(acdev, 0);

        ret = ata_host_activate(host, acdev->irq, irq_handler, 0,
                                &arasan_cf_sht);
        if (!ret)
                return 0;

        cf_exit(acdev);

        return ret;
}

static int arasan_cf_remove(struct platform_device *pdev)
{
        struct ata_host *host = platform_get_drvdata(pdev);
        struct arasan_cf_dev *acdev = host->ports[0]->private_data;

        ata_host_detach(host);
        cf_exit(acdev);

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int arasan_cf_suspend(struct device *dev)
{
        struct ata_host *host = dev_get_drvdata(dev);
        struct arasan_cf_dev *acdev = host->ports[0]->private_data;

        if (acdev->dma_chan)
                dmaengine_terminate_all(acdev->dma_chan);

        cf_exit(acdev);
        return ata_host_suspend(host, PMSG_SUSPEND);
}

static int arasan_cf_resume(struct device *dev)
{
        struct ata_host *host = dev_get_drvdata(dev);
        struct arasan_cf_dev *acdev = host->ports[0]->private_data;

        cf_init(acdev);
        ata_host_resume(host);

        return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(arasan_cf_pm_ops, arasan_cf_suspend, arasan_cf_resume);

#ifdef CONFIG_OF
static const struct of_device_id arasan_cf_id_table[] = {
        { .compatible = "arasan,cf-spear1340" },
        {}
};
MODULE_DEVICE_TABLE(of, arasan_cf_id_table);
#endif

static struct platform_driver arasan_cf_driver = {
        .probe          = arasan_cf_probe,
        .remove         = arasan_cf_remove,
        .driver         = {
                .name   = DRIVER_NAME,
                .pm     = &arasan_cf_pm_ops,
                .of_match_table = of_match_ptr(arasan_cf_id_table),
        },
};

module_platform_driver(arasan_cf_driver);

MODULE_AUTHOR("Viresh Kumar <vireshk@kernel.org>");
MODULE_DESCRIPTION("Arasan ATA Compact Flash driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRIVER_NAME);