/*
 * Renesas R-Car SATA driver
 *
 * Author: Vladimir Barinov <source@cogentembedded.com>
 * Copyright (C) 2013 Cogent Embedded, Inc.
 * Copyright (C) 2013 Renesas Solutions Corp.
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/ata.h>
#include <linux/libata.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/err.h>

#define DRV_NAME "sata_rcar"

/* SH-Navi2G/ATAPI-ATA compatible task registers */
#define DATA_REG                        0x100
#define SDEVCON_REG                     0x138

/* SH-Navi2G/ATAPI module compatible control registers */
#define ATAPI_CONTROL1_REG              0x180
#define ATAPI_STATUS_REG                0x184
#define ATAPI_INT_ENABLE_REG            0x188
#define ATAPI_DTB_ADR_REG               0x198
#define ATAPI_DMA_START_ADR_REG         0x19C
#define ATAPI_DMA_TRANS_CNT_REG         0x1A0
#define ATAPI_CONTROL2_REG              0x1A4
#define ATAPI_SIG_ST_REG                0x1B0
#define ATAPI_BYTE_SWAP_REG             0x1BC

/* ATAPI control 1 register (ATAPI_CONTROL1) bits */
#define ATAPI_CONTROL1_ISM              BIT(16)
#define ATAPI_CONTROL1_DTA32M           BIT(11)
#define ATAPI_CONTROL1_RESET            BIT(7)
#define ATAPI_CONTROL1_DESE             BIT(3)
#define ATAPI_CONTROL1_RW               BIT(2)
#define ATAPI_CONTROL1_STOP             BIT(1)
#define ATAPI_CONTROL1_START            BIT(0)

/* ATAPI status register (ATAPI_STATUS) bits */
#define ATAPI_STATUS_SATAINT            BIT(11)
#define ATAPI_STATUS_DNEND              BIT(6)
#define ATAPI_STATUS_DEVTRM             BIT(5)
#define ATAPI_STATUS_DEVINT             BIT(4)
#define ATAPI_STATUS_ERR                BIT(2)
#define ATAPI_STATUS_NEND               BIT(1)
#define ATAPI_STATUS_ACT                BIT(0)

/* Interrupt enable register (ATAPI_INT_ENABLE) bits */
#define ATAPI_INT_ENABLE_SATAINT        BIT(11)
#define ATAPI_INT_ENABLE_DNEND          BIT(6)
#define ATAPI_INT_ENABLE_DEVTRM         BIT(5)
#define ATAPI_INT_ENABLE_DEVINT         BIT(4)
#define ATAPI_INT_ENABLE_ERR            BIT(2)
#define ATAPI_INT_ENABLE_NEND           BIT(1)
#define ATAPI_INT_ENABLE_ACT            BIT(0)

/* Access control registers for physical layer control register */
#define SATAPHYADDR_REG                 0x200
#define SATAPHYWDATA_REG                0x204
#define SATAPHYACCEN_REG                0x208
#define SATAPHYRESET_REG                0x20C
#define SATAPHYRDATA_REG                0x210
#define SATAPHYACK_REG                  0x214

/* Physical layer control address command register (SATAPHYADDR) bits */
#define SATAPHYADDR_PHYRATEMODE         BIT(10)
#define SATAPHYADDR_PHYCMD_READ         BIT(9)
#define SATAPHYADDR_PHYCMD_WRITE        BIT(8)

/* Physical layer control enable register (SATAPHYACCEN) bits */
#define SATAPHYACCEN_PHYLANE            BIT(0)

/* Physical layer control reset register (SATAPHYRESET) bits */
#define SATAPHYRESET_PHYRST             BIT(1)
#define SATAPHYRESET_PHYSRES            BIT(0)

/* Physical layer control acknowledge register (SATAPHYACK) bits */
#define SATAPHYACK_PHYACK               BIT(0)

/* Serial-ATA HOST control registers */
#define BISTCONF_REG                    0x102C
#define SDATA_REG                       0x1100
#define SSDEVCON_REG                    0x1204

#define SCRSSTS_REG                     0x1400
#define SCRSERR_REG                     0x1404
#define SCRSCON_REG                     0x1408
#define SCRSACT_REG                     0x140C

#define SATAINTSTAT_REG                 0x1508
#define SATAINTMASK_REG                 0x150C

/* SATA INT status register (SATAINTSTAT) bits */
#define SATAINTSTAT_SERR                BIT(3)
#define SATAINTSTAT_ATA                 BIT(0)

/* SATA INT mask register (SATAINTSTAT) bits */
#define SATAINTMASK_SERRMSK             BIT(3)
#define SATAINTMASK_ERRMSK              BIT(2)
#define SATAINTMASK_ERRCRTMSK           BIT(1)
#define SATAINTMASK_ATAMSK              BIT(0)

#define SATA_RCAR_INT_MASK              (SATAINTMASK_SERRMSK | \
                                         SATAINTMASK_ATAMSK)

/* Physical Layer Control Registers */
#define SATAPCTLR1_REG                  0x43
#define SATAPCTLR2_REG                  0x52
#define SATAPCTLR3_REG                  0x5A
#define SATAPCTLR4_REG                  0x60

/* Descriptor table word 0 bit (when DTA32M = 1) */
#define SATA_RCAR_DTEND                 BIT(0)

struct sata_rcar_priv {
        void __iomem *base;
        struct clk *clk;
};

static void sata_rcar_phy_initialize(struct sata_rcar_priv *priv)
{
        /* idle state */
        iowrite32(0, priv->base + SATAPHYADDR_REG);
        /* reset */
        iowrite32(SATAPHYRESET_PHYRST, priv->base + SATAPHYRESET_REG);
        udelay(10);
        /* deassert reset */
        iowrite32(0, priv->base + SATAPHYRESET_REG);
}

static void sata_rcar_phy_write(struct sata_rcar_priv *priv, u16 reg, u32 val,
                                int group)
{
        int timeout;

        /* deassert reset */
        iowrite32(0, priv->base + SATAPHYRESET_REG);
        /* lane 1 */
        iowrite32(SATAPHYACCEN_PHYLANE, priv->base + SATAPHYACCEN_REG);
        /* write phy register value */
        iowrite32(val, priv->base + SATAPHYWDATA_REG);
        /* set register group */
        if (group)
                reg |= SATAPHYADDR_PHYRATEMODE;
        /* write command */
        iowrite32(SATAPHYADDR_PHYCMD_WRITE | reg, priv->base + SATAPHYADDR_REG);
        /* wait for ack */
        for (timeout = 0; timeout < 100; timeout++) {
                val = ioread32(priv->base + SATAPHYACK_REG);
                if (val & SATAPHYACK_PHYACK)
                        break;
        }
        if (timeout >= 100)
                pr_err("%s timeout\n", __func__);
        /* idle state */
        iowrite32(0, priv->base + SATAPHYADDR_REG);
}

static void sata_rcar_freeze(struct ata_port *ap)
{
        struct sata_rcar_priv *priv = ap->host->private_data;

        /* mask */
        iowrite32(0x7ff, priv->base + SATAINTMASK_REG);

        ata_sff_freeze(ap);
}

static void sata_rcar_thaw(struct ata_port *ap)
{
        struct sata_rcar_priv *priv = ap->host->private_data;

        /* ack */
        iowrite32(~SATA_RCAR_INT_MASK, priv->base + SATAINTSTAT_REG);

        ata_sff_thaw(ap);

        /* unmask */
        iowrite32(0x7ff & ~SATA_RCAR_INT_MASK, priv->base + SATAINTMASK_REG);
}

static void sata_rcar_ioread16_rep(void __iomem *reg, void *buffer, int count)
{
        u16 *ptr = buffer;

        while (count--) {
                u16 data = ioread32(reg);

                *ptr++ = data;
        }
}

static void sata_rcar_iowrite16_rep(void __iomem *reg, void *buffer, int count)
{
        const u16 *ptr = buffer;

        while (count--)
                iowrite32(*ptr++, reg);
}

static u8 sata_rcar_check_status(struct ata_port *ap)
{
        return ioread32(ap->ioaddr.status_addr);
}

static u8 sata_rcar_check_altstatus(struct ata_port *ap)
{
        return ioread32(ap->ioaddr.altstatus_addr);
}

static void sata_rcar_set_devctl(struct ata_port *ap, u8 ctl)
{
        iowrite32(ctl, ap->ioaddr.ctl_addr);
}

static void sata_rcar_dev_select(struct ata_port *ap, unsigned int device)
{
        iowrite32(ATA_DEVICE_OBS, ap->ioaddr.device_addr);
        ata_sff_pause(ap);      /* needed; also flushes, for mmio */
}

static unsigned int sata_rcar_ata_devchk(struct ata_port *ap,
                                         unsigned int device)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;
        u8 nsect, lbal;

        sata_rcar_dev_select(ap, device);

        iowrite32(0x55, ioaddr->nsect_addr);
        iowrite32(0xaa, ioaddr->lbal_addr);

        iowrite32(0xaa, ioaddr->nsect_addr);
        iowrite32(0x55, ioaddr->lbal_addr);

        iowrite32(0x55, ioaddr->nsect_addr);
        iowrite32(0xaa, ioaddr->lbal_addr);

        nsect = ioread32(ioaddr->nsect_addr);
        lbal  = ioread32(ioaddr->lbal_addr);

        if (nsect == 0x55 && lbal == 0xaa)
                return 1;       /* found a device */

        return 0;               /* nothing found */
}

static int sata_rcar_wait_after_reset(struct ata_link *link,
                                      unsigned long deadline)
{
        struct ata_port *ap = link->ap;

        ata_msleep(ap, ATA_WAIT_AFTER_RESET);

        return ata_sff_wait_ready(link, deadline);
}

static int sata_rcar_bus_softreset(struct ata_port *ap, unsigned long deadline)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;

        DPRINTK("ata%u: bus reset via SRST\n", ap->print_id);

        /* software reset.  causes dev0 to be selected */
        iowrite32(ap->ctl, ioaddr->ctl_addr);
        udelay(20);
        iowrite32(ap->ctl | ATA_SRST, ioaddr->ctl_addr);
        udelay(20);
        iowrite32(ap->ctl, ioaddr->ctl_addr);
        ap->last_ctl = ap->ctl;

        /* wait the port to become ready */
        return sata_rcar_wait_after_reset(&ap->link, deadline);
}

static int sata_rcar_softreset(struct ata_link *link, unsigned int *classes,
                               unsigned long deadline)
{
        struct ata_port *ap = link->ap;
        unsigned int devmask = 0;
        int rc;
        u8 err;

        /* determine if device 0 is present */
        if (sata_rcar_ata_devchk(ap, 0))
                devmask |= 1 << 0;

        /* issue bus reset */
        DPRINTK("about to softreset, devmask=%x\n", devmask);
        rc = sata_rcar_bus_softreset(ap, deadline);
        /* if link is occupied, -ENODEV too is an error */
        if (rc && (rc != -ENODEV || sata_scr_valid(link))) {
                ata_link_err(link, "SRST failed (errno=%d)\n", rc);
                return rc;
        }

        /* determine by signature whether we have ATA or ATAPI devices */
        classes[0] = ata_sff_dev_classify(&link->device[0], devmask, &err);

        DPRINTK("classes[0]=%u\n", classes[0]);
        return 0;
}

static void sata_rcar_tf_load(struct ata_port *ap,
                              const struct ata_taskfile *tf)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;
        unsigned int is_addr = tf->flags & ATA_TFLAG_ISADDR;

        if (tf->ctl != ap->last_ctl) {
                iowrite32(tf->ctl, ioaddr->ctl_addr);
                ap->last_ctl = tf->ctl;
                ata_wait_idle(ap);
        }

        if (is_addr && (tf->flags & ATA_TFLAG_LBA48)) {
                iowrite32(tf->hob_feature, ioaddr->feature_addr);
                iowrite32(tf->hob_nsect, ioaddr->nsect_addr);
                iowrite32(tf->hob_lbal, ioaddr->lbal_addr);
                iowrite32(tf->hob_lbam, ioaddr->lbam_addr);
                iowrite32(tf->hob_lbah, ioaddr->lbah_addr);
                VPRINTK("hob: feat 0x%X nsect 0x%X, lba 0x%X 0x%X 0x%X\n",
                        tf->hob_feature,
                        tf->hob_nsect,
                        tf->hob_lbal,
                        tf->hob_lbam,
                        tf->hob_lbah);
        }

        if (is_addr) {
                iowrite32(tf->feature, ioaddr->feature_addr);
                iowrite32(tf->nsect, ioaddr->nsect_addr);
                iowrite32(tf->lbal, ioaddr->lbal_addr);
                iowrite32(tf->lbam, ioaddr->lbam_addr);
                iowrite32(tf->lbah, ioaddr->lbah_addr);
                VPRINTK("feat 0x%X nsect 0x%X lba 0x%X 0x%X 0x%X\n",
                        tf->feature,
                        tf->nsect,
                        tf->lbal,
                        tf->lbam,
                        tf->lbah);
        }

        if (tf->flags & ATA_TFLAG_DEVICE) {
                iowrite32(tf->device, ioaddr->device_addr);
                VPRINTK("device 0x%X\n", tf->device);
        }

        ata_wait_idle(ap);
}

static void sata_rcar_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;

        tf->command = sata_rcar_check_status(ap);
        tf->feature = ioread32(ioaddr->error_addr);
        tf->nsect = ioread32(ioaddr->nsect_addr);
        tf->lbal = ioread32(ioaddr->lbal_addr);
        tf->lbam = ioread32(ioaddr->lbam_addr);
        tf->lbah = ioread32(ioaddr->lbah_addr);
        tf->device = ioread32(ioaddr->device_addr);

        if (tf->flags & ATA_TFLAG_LBA48) {
                iowrite32(tf->ctl | ATA_HOB, ioaddr->ctl_addr);
                tf->hob_feature = ioread32(ioaddr->error_addr);
                tf->hob_nsect = ioread32(ioaddr->nsect_addr);
                tf->hob_lbal = ioread32(ioaddr->lbal_addr);
                tf->hob_lbam = ioread32(ioaddr->lbam_addr);
                tf->hob_lbah = ioread32(ioaddr->lbah_addr);
                iowrite32(tf->ctl, ioaddr->ctl_addr);
                ap->last_ctl = tf->ctl;
        }
}

static void sata_rcar_exec_command(struct ata_port *ap,
                                   const struct ata_taskfile *tf)
{
        DPRINTK("ata%u: cmd 0x%X\n", ap->print_id, tf->command);

        iowrite32(tf->command, ap->ioaddr.command_addr);
        ata_sff_pause(ap);
}

static unsigned int sata_rcar_data_xfer(struct ata_device *dev,
                                              unsigned char *buf,
                                              unsigned int buflen, int rw)
{
        struct ata_port *ap = dev->link->ap;
        void __iomem *data_addr = ap->ioaddr.data_addr;
        unsigned int words = buflen >> 1;

        /* Transfer multiple of 2 bytes */
        if (rw == READ)
                sata_rcar_ioread16_rep(data_addr, buf, words);
        else
                sata_rcar_iowrite16_rep(data_addr, buf, words);

        /* Transfer trailing byte, if any. */
        if (unlikely(buflen & 0x01)) {
                unsigned char pad[2] = { };

                /* Point buf to the tail of buffer */
                buf += buflen - 1;

                /*
                 * Use io*16_rep() accessors here as well to avoid pointlessly
                 * swapping bytes to and from on the big endian machines...
                 */
                if (rw == READ) {
                        sata_rcar_ioread16_rep(data_addr, pad, 1);
                        *buf = pad[0];
                } else {
                        pad[0] = *buf;
                        sata_rcar_iowrite16_rep(data_addr, pad, 1);
                }
                words++;
        }

        return words << 1;
}

static void sata_rcar_drain_fifo(struct ata_queued_cmd *qc)
{
        int count;
        struct ata_port *ap;

        /* We only need to flush incoming data when a command was running */
        if (qc == NULL || qc->dma_dir == DMA_TO_DEVICE)
                return;

        ap = qc->ap;
        /* Drain up to 64K of data before we give up this recovery method */
        for (count = 0; (ap->ops->sff_check_status(ap) & ATA_DRQ) &&
                        count < 65536; count += 2)
                ioread32(ap->ioaddr.data_addr);

        /* Can become DEBUG later */
        if (count)
                ata_port_dbg(ap, "drained %d bytes to clear DRQ\n", count);
}

static int sata_rcar_scr_read(struct ata_link *link, unsigned int sc_reg,
                              u32 *val)
{
        if (sc_reg > SCR_ACTIVE)
                return -EINVAL;

        *val = ioread32(link->ap->ioaddr.scr_addr + (sc_reg << 2));
        return 0;
}

static int sata_rcar_scr_write(struct ata_link *link, unsigned int sc_reg,
                               u32 val)
{
        if (sc_reg > SCR_ACTIVE)
                return -EINVAL;

        iowrite32(val, link->ap->ioaddr.scr_addr + (sc_reg << 2));
        return 0;
}

static void sata_rcar_bmdma_fill_sg(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        struct ata_bmdma_prd *prd = ap->bmdma_prd;
        struct scatterlist *sg;
        unsigned int si, pi;

        pi = 0;
        for_each_sg(qc->sg, sg, qc->n_elem, si) {
                u32 addr, sg_len, len;

                /*
                 * Note: h/w doesn't support 64-bit, so we unconditionally
                 * truncate dma_addr_t to u32.
                 */
                addr = (u32)sg_dma_address(sg);
                sg_len = sg_dma_len(sg);

                /* H/w transfer count is only 29 bits long, let's be careful */
                while (sg_len) {
                        len = sg_len;
                        if (len > 0x1ffffffe)
                                len = 0x1ffffffe;

                        prd[pi].addr = cpu_to_le32(addr);
                        prd[pi].flags_len = cpu_to_le32(len);
                        VPRINTK("PRD[%u] = (0x%X, 0x%X)\n", pi, addr, len);

                        pi++;
                        sg_len -= len;
                        addr += len;
                }
        }

        /* end-of-table flag */
        prd[pi - 1].addr |= cpu_to_le32(SATA_RCAR_DTEND);
}

static void sata_rcar_qc_prep(struct ata_queued_cmd *qc)
{
        if (!(qc->flags & ATA_QCFLAG_DMAMAP))
                return;

        sata_rcar_bmdma_fill_sg(qc);
}

static void sata_rcar_bmdma_setup(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        unsigned int rw = qc->tf.flags & ATA_TFLAG_WRITE;
        u32 dmactl;
        struct sata_rcar_priv *priv = ap->host->private_data;

        /* load PRD table addr. */
        mb();   /* make sure PRD table writes are visible to controller */
        iowrite32(ap->bmdma_prd_dma, priv->base + ATAPI_DTB_ADR_REG);

        /* specify data direction, triple-check start bit is clear */
        dmactl = ioread32(priv->base + ATAPI_CONTROL1_REG);
        dmactl &= ~(ATAPI_CONTROL1_RW | ATAPI_CONTROL1_STOP);
        if (dmactl & ATAPI_CONTROL1_START) {
                dmactl &= ~ATAPI_CONTROL1_START;
                dmactl |= ATAPI_CONTROL1_STOP;
        }
        if (!rw)
                dmactl |= ATAPI_CONTROL1_RW;
        iowrite32(dmactl, priv->base + ATAPI_CONTROL1_REG);

        /* issue r/w command */
        ap->ops->sff_exec_command(ap, &qc->tf);
}

static void sata_rcar_bmdma_start(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        u32 dmactl;
        struct sata_rcar_priv *priv = ap->host->private_data;

        /* start host DMA transaction */
        dmactl = ioread32(priv->base + ATAPI_CONTROL1_REG);
        dmactl &= ~ATAPI_CONTROL1_STOP;
        dmactl |= ATAPI_CONTROL1_START;
        iowrite32(dmactl, priv->base + ATAPI_CONTROL1_REG);
}

static void sata_rcar_bmdma_stop(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        struct sata_rcar_priv *priv = ap->host->private_data;
        u32 dmactl;

        /* force termination of DMA transfer if active */
        dmactl = ioread32(priv->base + ATAPI_CONTROL1_REG);
        if (dmactl & ATAPI_CONTROL1_START) {
                dmactl &= ~ATAPI_CONTROL1_START;
                dmactl |= ATAPI_CONTROL1_STOP;
                iowrite32(dmactl, priv->base + ATAPI_CONTROL1_REG);
        }

        /* one-PIO-cycle guaranteed wait, per spec, for HDMA1:0 transition */
        ata_sff_dma_pause(ap);
}

static u8 sata_rcar_bmdma_status(struct ata_port *ap)
{
        struct sata_rcar_priv *priv = ap->host->private_data;
        u32 status;
        u8 host_stat = 0;

        status = ioread32(priv->base + ATAPI_STATUS_REG);
        if (status & ATAPI_STATUS_DEVINT)
                host_stat |= ATA_DMA_INTR;
        if (status & ATAPI_STATUS_ACT)
                host_stat |= ATA_DMA_ACTIVE;

        return host_stat;
}

static struct scsi_host_template sata_rcar_sht = {
        ATA_BMDMA_SHT(DRV_NAME),
};

static struct ata_port_operations sata_rcar_port_ops = {
        .inherits               = &ata_bmdma_port_ops,

        .freeze                 = sata_rcar_freeze,
        .thaw                   = sata_rcar_thaw,
        .softreset              = sata_rcar_softreset,

        .scr_read               = sata_rcar_scr_read,
        .scr_write              = sata_rcar_scr_write,

        .sff_dev_select         = sata_rcar_dev_select,
        .sff_set_devctl         = sata_rcar_set_devctl,
        .sff_check_status       = sata_rcar_check_status,
        .sff_check_altstatus    = sata_rcar_check_altstatus,
        .sff_tf_load            = sata_rcar_tf_load,
        .sff_tf_read            = sata_rcar_tf_read,
        .sff_exec_command       = sata_rcar_exec_command,
        .sff_data_xfer          = sata_rcar_data_xfer,
        .sff_drain_fifo         = sata_rcar_drain_fifo,

        .qc_prep                = sata_rcar_qc_prep,

        .bmdma_setup            = sata_rcar_bmdma_setup,
        .bmdma_start            = sata_rcar_bmdma_start,
        .bmdma_stop             = sata_rcar_bmdma_stop,
        .bmdma_status           = sata_rcar_bmdma_status,
};

static void sata_rcar_serr_interrupt(struct ata_port *ap)
{
        struct sata_rcar_priv *priv = ap->host->private_data;
        struct ata_eh_info *ehi = &ap->link.eh_info;
        int freeze = 0;
        u32 serror;

        serror = ioread32(priv->base + SCRSERR_REG);
        if (!serror)
                return;

        DPRINTK("SError @host_intr: 0x%x\n", serror);

        /* first, analyze and record host port events */
        ata_ehi_clear_desc(ehi);

        if (serror & (SERR_DEV_XCHG | SERR_PHYRDY_CHG)) {
                /* Setup a soft-reset EH action */
                ata_ehi_hotplugged(ehi);
                ata_ehi_push_desc(ehi, "%s", "hotplug");

                freeze = serror & SERR_COMM_WAKE ? 0 : 1;
        }

        /* freeze or abort */
        if (freeze)
                ata_port_freeze(ap);
        else
                ata_port_abort(ap);
}

static void sata_rcar_ata_interrupt(struct ata_port *ap)
{
        struct ata_queued_cmd *qc;
        int handled = 0;

        qc = ata_qc_from_tag(ap, ap->link.active_tag);
        if (qc)
                handled |= ata_bmdma_port_intr(ap, qc);

        /* be sure to clear ATA interrupt */
        if (!handled)
                sata_rcar_check_status(ap);
}

static irqreturn_t sata_rcar_interrupt(int irq, void *dev_instance)
{
        struct ata_host *host = dev_instance;
        struct sata_rcar_priv *priv = host->private_data;
        struct ata_port *ap;
        unsigned int handled = 0;
        u32 sataintstat;
        unsigned long flags;

        spin_lock_irqsave(&host->lock, flags);

        sataintstat = ioread32(priv->base + SATAINTSTAT_REG);
        sataintstat &= SATA_RCAR_INT_MASK;
        if (!sataintstat)
                goto done;
        /* ack */
        iowrite32(~sataintstat & 0x7ff, priv->base + SATAINTSTAT_REG);

        ap = host->ports[0];

        if (sataintstat & SATAINTSTAT_ATA)
                sata_rcar_ata_interrupt(ap);

        if (sataintstat & SATAINTSTAT_SERR)
                sata_rcar_serr_interrupt(ap);

        handled = 1;
done:
        spin_unlock_irqrestore(&host->lock, flags);

        return IRQ_RETVAL(handled);
}

static void sata_rcar_setup_port(struct ata_host *host)
{
        struct ata_port *ap = host->ports[0];
        struct ata_ioports *ioaddr = &ap->ioaddr;
        struct sata_rcar_priv *priv = host->private_data;

        ap->ops         = &sata_rcar_port_ops;
        ap->pio_mask    = ATA_PIO4;
        ap->udma_mask   = ATA_UDMA6;
        ap->flags       |= ATA_FLAG_SATA;

        ioaddr->cmd_addr = priv->base + SDATA_REG;
        ioaddr->ctl_addr = priv->base + SSDEVCON_REG;
        ioaddr->scr_addr = priv->base + SCRSSTS_REG;
        ioaddr->altstatus_addr = ioaddr->ctl_addr;

        ioaddr->data_addr       = ioaddr->cmd_addr + (ATA_REG_DATA << 2);
        ioaddr->error_addr      = ioaddr->cmd_addr + (ATA_REG_ERR << 2);
        ioaddr->feature_addr    = ioaddr->cmd_addr + (ATA_REG_FEATURE << 2);
        ioaddr->nsect_addr      = ioaddr->cmd_addr + (ATA_REG_NSECT << 2);
        ioaddr->lbal_addr       = ioaddr->cmd_addr + (ATA_REG_LBAL << 2);
        ioaddr->lbam_addr       = ioaddr->cmd_addr + (ATA_REG_LBAM << 2);
        ioaddr->lbah_addr       = ioaddr->cmd_addr + (ATA_REG_LBAH << 2);
        ioaddr->device_addr     = ioaddr->cmd_addr + (ATA_REG_DEVICE << 2);
        ioaddr->status_addr     = ioaddr->cmd_addr + (ATA_REG_STATUS << 2);
        ioaddr->command_addr    = ioaddr->cmd_addr + (ATA_REG_CMD << 2);
}

static void sata_rcar_init_controller(struct ata_host *host)
{
        struct sata_rcar_priv *priv = host->private_data;
        u32 val;

        /* reset and setup phy */
        sata_rcar_phy_initialize(priv);
        sata_rcar_phy_write(priv, SATAPCTLR1_REG, 0x00200188, 0);
        sata_rcar_phy_write(priv, SATAPCTLR1_REG, 0x00200188, 1);
        sata_rcar_phy_write(priv, SATAPCTLR3_REG, 0x0000A061, 0);
        sata_rcar_phy_write(priv, SATAPCTLR2_REG, 0x20000000, 0);
        sata_rcar_phy_write(priv, SATAPCTLR2_REG, 0x20000000, 1);
        sata_rcar_phy_write(priv, SATAPCTLR4_REG, 0x28E80000, 0);

        /* SATA-IP reset state */
        val = ioread32(priv->base + ATAPI_CONTROL1_REG);
        val |= ATAPI_CONTROL1_RESET;
        iowrite32(val, priv->base + ATAPI_CONTROL1_REG);

        /* ISM mode, PRD mode, DTEND flag at bit 0 */
        val = ioread32(priv->base + ATAPI_CONTROL1_REG);
        val |= ATAPI_CONTROL1_ISM;
        val |= ATAPI_CONTROL1_DESE;
        val |= ATAPI_CONTROL1_DTA32M;
        iowrite32(val, priv->base + ATAPI_CONTROL1_REG);

        /* Release the SATA-IP from the reset state */
        val = ioread32(priv->base + ATAPI_CONTROL1_REG);
        val &= ~ATAPI_CONTROL1_RESET;
        iowrite32(val, priv->base + ATAPI_CONTROL1_REG);

        /* ack and mask */
        iowrite32(0, priv->base + SATAINTSTAT_REG);
        iowrite32(0x7ff, priv->base + SATAINTMASK_REG);
        /* enable interrupts */
        iowrite32(ATAPI_INT_ENABLE_SATAINT, priv->base + ATAPI_INT_ENABLE_REG);
}

static int sata_rcar_probe(struct platform_device *pdev)
{
        struct ata_host *host;
        struct sata_rcar_priv *priv;
        struct resource *mem;
        int irq;
        int ret = 0;

        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (mem == NULL)
                return -EINVAL;

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

        priv = devm_kzalloc(&pdev->dev, sizeof(struct sata_rcar_priv),
                           GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        priv->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(priv->clk)) {
                dev_err(&pdev->dev, "failed to get access to sata clock\n");
                return PTR_ERR(priv->clk);
        }
        clk_enable(priv->clk);

        host = ata_host_alloc(&pdev->dev, 1);
        if (!host) {
                dev_err(&pdev->dev, "ata_host_alloc failed\n");
                ret = -ENOMEM;
                goto cleanup;
        }

        host->private_data = priv;

        priv->base = devm_ioremap_resource(&pdev->dev, mem);
        if (IS_ERR(priv->base)) {
                ret = PTR_ERR(priv->base);
                goto cleanup;
        }

        /* setup port */
        sata_rcar_setup_port(host);

        /* initialize host controller */
        sata_rcar_init_controller(host);

        ret = ata_host_activate(host, irq, sata_rcar_interrupt, 0,
                                &sata_rcar_sht);
        if (!ret)
                return 0;

cleanup:
        clk_disable(priv->clk);

        return ret;
}

static int sata_rcar_remove(struct platform_device *pdev)
{
        struct ata_host *host = dev_get_drvdata(&pdev->dev);
        struct sata_rcar_priv *priv = host->private_data;

        ata_host_detach(host);

        /* disable interrupts */
        iowrite32(0, priv->base + ATAPI_INT_ENABLE_REG);
        /* ack and mask */
        iowrite32(0, priv->base + SATAINTSTAT_REG);
        iowrite32(0x7ff, priv->base + SATAINTMASK_REG);

        clk_disable(priv->clk);

        return 0;
}

#ifdef CONFIG_PM
static int sata_rcar_suspend(struct device *dev)
{
        struct ata_host *host = dev_get_drvdata(dev);
        struct sata_rcar_priv *priv = host->private_data;
        int ret;

        ret = ata_host_suspend(host, PMSG_SUSPEND);
        if (!ret) {
                /* disable interrupts */
                iowrite32(0, priv->base + ATAPI_INT_ENABLE_REG);
                /* mask */
                iowrite32(0x7ff, priv->base + SATAINTMASK_REG);

                clk_disable(priv->clk);
        }

        return ret;
}

static int sata_rcar_resume(struct device *dev)
{
        struct ata_host *host = dev_get_drvdata(dev);
        struct sata_rcar_priv *priv = host->private_data;

        clk_enable(priv->clk);

        /* ack and mask */
        iowrite32(0, priv->base + SATAINTSTAT_REG);
        iowrite32(0x7ff, priv->base + SATAINTMASK_REG);
        /* enable interrupts */
        iowrite32(ATAPI_INT_ENABLE_SATAINT, priv->base + ATAPI_INT_ENABLE_REG);

        ata_host_resume(host);

        return 0;
}

static const struct dev_pm_ops sata_rcar_pm_ops = {
        .suspend        = sata_rcar_suspend,
        .resume         = sata_rcar_resume,
};
#endif

static struct of_device_id sata_rcar_match[] = {
        { .compatible = "renesas,rcar-sata", },
        {},
};
MODULE_DEVICE_TABLE(of, sata_rcar_match);

static struct platform_driver sata_rcar_driver = {
        .probe          = sata_rcar_probe,
        .remove         = sata_rcar_remove,
        .driver = {
                .name           = DRV_NAME,
                .owner          = THIS_MODULE,
                .of_match_table = sata_rcar_match,
#ifdef CONFIG_PM
                .pm             = &sata_rcar_pm_ops,
#endif
        },
};

module_platform_driver(sata_rcar_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Vladimir Barinov");
MODULE_DESCRIPTION("Renesas R-Car SATA controller low level driver");