/*
 * drivers/ata/sata_dwc_460ex.c
 *
 * Synopsys DesignWare Cores (DWC) SATA host driver
 *
 * Author: Mark Miesfeld <mmiesfeld@amcc.com>
 *
 * Ported from 2.6.19.2 to 2.6.25/26 by Stefan Roese <sr@denx.de>
 * Copyright 2008 DENX Software Engineering
 *
 * Based on versions provided by AMCC and Synopsys which are:
 *          Copyright 2006 Applied Micro Circuits Corporation
 *          COPYRIGHT (C) 2005  SYNOPSYS, INC.  ALL RIGHTS RESERVED
 *
 * 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.
 */

#ifdef CONFIG_SATA_DWC_DEBUG
#define DEBUG
#endif

#ifdef CONFIG_SATA_DWC_VDEBUG
#define VERBOSE_DEBUG
#define DEBUG_NCQ
#endif

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/libata.h>
#include <linux/slab.h>
#include "libata.h"

#include <scsi/scsi_host.h>
#include <scsi/scsi_cmnd.h>

/* These two are defined in "libata.h" */
#undef  DRV_NAME
#undef  DRV_VERSION

#define DRV_NAME        "sata-dwc"
#define DRV_VERSION     "1.3"

/* SATA DMA driver Globals */
#define DMA_NUM_CHANS           1
#define DMA_NUM_CHAN_REGS       8

/* SATA DMA Register definitions */
#define AHB_DMA_BRST_DFLT       64      /* 16 data items burst length*/

struct dmareg {
        u32 low;                /* Low bits 0-31 */
        u32 high;               /* High bits 32-63 */
};

/* DMA Per Channel registers */
struct dma_chan_regs {
        struct dmareg sar;      /* Source Address */
        struct dmareg dar;      /* Destination address */
        struct dmareg llp;      /* Linked List Pointer */
        struct dmareg ctl;      /* Control */
        struct dmareg sstat;    /* Source Status not implemented in core */
        struct dmareg dstat;    /* Destination Status not implemented in core*/
        struct dmareg sstatar;  /* Source Status Address not impl in core */
        struct dmareg dstatar;  /* Destination Status Address not implemente */
        struct dmareg cfg;      /* Config */
        struct dmareg sgr;      /* Source Gather */
        struct dmareg dsr;      /* Destination Scatter */
};

/* Generic Interrupt Registers */
struct dma_interrupt_regs {
        struct dmareg tfr;      /* Transfer Interrupt */
        struct dmareg block;    /* Block Interrupt */
        struct dmareg srctran;  /* Source Transfer Interrupt */
        struct dmareg dsttran;  /* Dest Transfer Interrupt */
        struct dmareg error;    /* Error */
};

struct ahb_dma_regs {
        struct dma_chan_regs    chan_regs[DMA_NUM_CHAN_REGS];
        struct dma_interrupt_regs interrupt_raw;        /* Raw Interrupt */
        struct dma_interrupt_regs interrupt_status;     /* Interrupt Status */
        struct dma_interrupt_regs interrupt_mask;       /* Interrupt Mask */
        struct dma_interrupt_regs interrupt_clear;      /* Interrupt Clear */
        struct dmareg           statusInt;      /* Interrupt combined*/
        struct dmareg           rq_srcreg;      /* Src Trans Req */
        struct dmareg           rq_dstreg;      /* Dst Trans Req */
        struct dmareg           rq_sgl_srcreg;  /* Sngl Src Trans Req*/
        struct dmareg           rq_sgl_dstreg;  /* Sngl Dst Trans Req*/
        struct dmareg           rq_lst_srcreg;  /* Last Src Trans Req*/
        struct dmareg           rq_lst_dstreg;  /* Last Dst Trans Req*/
        struct dmareg           dma_cfg;                /* DMA Config */
        struct dmareg           dma_chan_en;            /* DMA Channel Enable*/
        struct dmareg           dma_id;                 /* DMA ID */
        struct dmareg           dma_test;               /* DMA Test */
        struct dmareg           res1;                   /* reserved */
        struct dmareg           res2;                   /* reserved */
        /*
         * DMA Comp Params
         * Param 6 = dma_param[0], Param 5 = dma_param[1],
         * Param 4 = dma_param[2] ...
         */
        struct dmareg           dma_params[6];
};

/* Data structure for linked list item */
struct lli {
        u32             sar;            /* Source Address */
        u32             dar;            /* Destination address */
        u32             llp;            /* Linked List Pointer */
        struct dmareg   ctl;            /* Control */
        struct dmareg   dstat;          /* Destination Status */
};

enum {
        SATA_DWC_DMAC_LLI_SZ =  (sizeof(struct lli)),
        SATA_DWC_DMAC_LLI_NUM = 256,
        SATA_DWC_DMAC_LLI_TBL_SZ = (SATA_DWC_DMAC_LLI_SZ * \
                                        SATA_DWC_DMAC_LLI_NUM),
        SATA_DWC_DMAC_TWIDTH_BYTES = 4,
        SATA_DWC_DMAC_CTRL_TSIZE_MAX = (0x00000800 * \
                                                SATA_DWC_DMAC_TWIDTH_BYTES),
};

/* DMA Register Operation Bits */
enum {
        DMA_EN  =               0x00000001, /* Enable AHB DMA */
        DMA_CTL_LLP_SRCEN =     0x10000000, /* Blk chain enable Src */
        DMA_CTL_LLP_DSTEN =     0x08000000, /* Blk chain enable Dst */
};

#define DMA_CTL_BLK_TS(size)    ((size) & 0x000000FFF)  /* Blk Transfer size */
#define DMA_CHANNEL(ch)         (0x00000001 << (ch))    /* Select channel */
        /* Enable channel */
#define DMA_ENABLE_CHAN(ch)     ((0x00000001 << (ch)) |                 \
                                 ((0x000000001 << (ch)) << 8))
        /* Disable channel */
#define DMA_DISABLE_CHAN(ch)    (0x00000000 | ((0x000000001 << (ch)) << 8))
        /* Transfer Type & Flow Controller */
#define DMA_CTL_TTFC(type)      (((type) & 0x7) << 20)
#define DMA_CTL_SMS(num)        (((num) & 0x3) << 25) /* Src Master Select */
#define DMA_CTL_DMS(num)        (((num) & 0x3) << 23)/* Dst Master Select */
        /* Src Burst Transaction Length */
#define DMA_CTL_SRC_MSIZE(size) (((size) & 0x7) << 14)
        /* Dst Burst Transaction Length */
#define DMA_CTL_DST_MSIZE(size) (((size) & 0x7) << 11)
        /* Source Transfer Width */
#define DMA_CTL_SRC_TRWID(size) (((size) & 0x7) << 4)
        /* Destination Transfer Width */
#define DMA_CTL_DST_TRWID(size) (((size) & 0x7) << 1)

/* Assign HW handshaking interface (x) to destination / source peripheral */
#define DMA_CFG_HW_HS_DEST(int_num) (((int_num) & 0xF) << 11)
#define DMA_CFG_HW_HS_SRC(int_num) (((int_num) & 0xF) << 7)
#define DMA_CFG_HW_CH_PRIOR(int_num) (((int_num) & 0xF) << 5)
#define DMA_LLP_LMS(addr, master) (((addr) & 0xfffffffc) | (master))

/*
 * This define is used to set block chaining disabled in the control low
 * register.  It is already in little endian format so it can be &'d dirctly.
 * It is essentially: cpu_to_le32(~(DMA_CTL_LLP_SRCEN | DMA_CTL_LLP_DSTEN))
 */
enum {
        DMA_CTL_LLP_DISABLE_LE32 = 0xffffffe7,
        DMA_CTL_TTFC_P2M_DMAC = 0x00000002, /* Per to mem, DMAC cntr */
        DMA_CTL_TTFC_M2P_PER =  0x00000003, /* Mem to per, peripheral cntr */
        DMA_CTL_SINC_INC =      0x00000000, /* Source Address Increment */
        DMA_CTL_SINC_DEC =      0x00000200,
        DMA_CTL_SINC_NOCHANGE = 0x00000400,
        DMA_CTL_DINC_INC =      0x00000000, /* Destination Address Increment */
        DMA_CTL_DINC_DEC =      0x00000080,
        DMA_CTL_DINC_NOCHANGE = 0x00000100,
        DMA_CTL_INT_EN =        0x00000001, /* Interrupt Enable */

/* Channel Configuration Register high bits */
        DMA_CFG_FCMOD_REQ =     0x00000001, /* Flow Control - request based */
        DMA_CFG_PROTCTL =       (0x00000003 << 2),/* Protection Control */

/* Channel Configuration Register low bits */
        DMA_CFG_RELD_DST =      0x80000000, /* Reload Dest / Src Addr */
        DMA_CFG_RELD_SRC =      0x40000000,
        DMA_CFG_HS_SELSRC =     0x00000800, /* Software handshake Src/ Dest */
        DMA_CFG_HS_SELDST =     0x00000400,
        DMA_CFG_FIFOEMPTY =     (0x00000001 << 9), /* FIFO Empty bit */

/* Channel Linked List Pointer Register */
        DMA_LLP_AHBMASTER1 =    0,      /* List Master Select */
        DMA_LLP_AHBMASTER2 =    1,

        SATA_DWC_MAX_PORTS = 1,

        SATA_DWC_SCR_OFFSET = 0x24,
        SATA_DWC_REG_OFFSET = 0x64,
};

/* DWC SATA Registers */
struct sata_dwc_regs {
        u32 fptagr;             /* 1st party DMA tag */
        u32 fpbor;              /* 1st party DMA buffer offset */
        u32 fptcr;              /* 1st party DMA Xfr count */
        u32 dmacr;              /* DMA Control */
        u32 dbtsr;              /* DMA Burst Transac size */
        u32 intpr;              /* Interrupt Pending */
        u32 intmr;              /* Interrupt Mask */
        u32 errmr;              /* Error Mask */
        u32 llcr;               /* Link Layer Control */
        u32 phycr;              /* PHY Control */
        u32 physr;              /* PHY Status */
        u32 rxbistpd;           /* Recvd BIST pattern def register */
        u32 rxbistpd1;          /* Recvd BIST data dword1 */
        u32 rxbistpd2;          /* Recvd BIST pattern data dword2 */
        u32 txbistpd;           /* Trans BIST pattern def register */
        u32 txbistpd1;          /* Trans BIST data dword1 */
        u32 txbistpd2;          /* Trans BIST data dword2 */
        u32 bistcr;             /* BIST Control Register */
        u32 bistfctr;           /* BIST FIS Count Register */
        u32 bistsr;             /* BIST Status Register */
        u32 bistdecr;           /* BIST Dword Error count register */
        u32 res[15];            /* Reserved locations */
        u32 testr;              /* Test Register */
        u32 versionr;           /* Version Register */
        u32 idr;                /* ID Register */
        u32 unimpl[192];        /* Unimplemented */
        u32 dmadr[256]; /* FIFO Locations in DMA Mode */
};

enum {
        SCR_SCONTROL_DET_ENABLE =       0x00000001,
        SCR_SSTATUS_DET_PRESENT =       0x00000001,
        SCR_SERROR_DIAG_X       =       0x04000000,
/* DWC SATA Register Operations */
        SATA_DWC_TXFIFO_DEPTH   =       0x01FF,
        SATA_DWC_RXFIFO_DEPTH   =       0x01FF,
        SATA_DWC_DMACR_TMOD_TXCHEN =    0x00000004,
        SATA_DWC_DMACR_TXCHEN   = (0x00000001 | SATA_DWC_DMACR_TMOD_TXCHEN),
        SATA_DWC_DMACR_RXCHEN   = (0x00000002 | SATA_DWC_DMACR_TMOD_TXCHEN),
        SATA_DWC_DMACR_TXRXCH_CLEAR =   SATA_DWC_DMACR_TMOD_TXCHEN,
        SATA_DWC_INTPR_DMAT     =       0x00000001,
        SATA_DWC_INTPR_NEWFP    =       0x00000002,
        SATA_DWC_INTPR_PMABRT   =       0x00000004,
        SATA_DWC_INTPR_ERR      =       0x00000008,
        SATA_DWC_INTPR_NEWBIST  =       0x00000010,
        SATA_DWC_INTPR_IPF      =       0x10000000,
        SATA_DWC_INTMR_DMATM    =       0x00000001,
        SATA_DWC_INTMR_NEWFPM   =       0x00000002,
        SATA_DWC_INTMR_PMABRTM  =       0x00000004,
        SATA_DWC_INTMR_ERRM     =       0x00000008,
        SATA_DWC_INTMR_NEWBISTM =       0x00000010,
        SATA_DWC_LLCR_SCRAMEN   =       0x00000001,
        SATA_DWC_LLCR_DESCRAMEN =       0x00000002,
        SATA_DWC_LLCR_RPDEN     =       0x00000004,
/* This is all error bits, zero's are reserved fields. */
        SATA_DWC_SERROR_ERR_BITS =      0x0FFF0F03
};

#define SATA_DWC_SCR0_SPD_GET(v)        (((v) >> 4) & 0x0000000F)
#define SATA_DWC_DMACR_TX_CLEAR(v)      (((v) & ~SATA_DWC_DMACR_TXCHEN) |\
                                                 SATA_DWC_DMACR_TMOD_TXCHEN)
#define SATA_DWC_DMACR_RX_CLEAR(v)      (((v) & ~SATA_DWC_DMACR_RXCHEN) |\
                                                 SATA_DWC_DMACR_TMOD_TXCHEN)
#define SATA_DWC_DBTSR_MWR(size)        (((size)/4) & SATA_DWC_TXFIFO_DEPTH)
#define SATA_DWC_DBTSR_MRD(size)        ((((size)/4) & SATA_DWC_RXFIFO_DEPTH)\
                                                 << 16)
struct sata_dwc_device {
        struct device           *dev;           /* generic device struct */
        struct ata_probe_ent    *pe;            /* ptr to probe-ent */
        struct ata_host         *host;
        u8                      *reg_base;
        struct sata_dwc_regs    *sata_dwc_regs; /* DW Synopsys SATA specific */
        int                     irq_dma;
};

#define SATA_DWC_QCMD_MAX       32

struct sata_dwc_device_port {
        struct sata_dwc_device  *hsdev;
        int                     cmd_issued[SATA_DWC_QCMD_MAX];
        struct lli              *llit[SATA_DWC_QCMD_MAX];  /* DMA LLI table */
        dma_addr_t              llit_dma[SATA_DWC_QCMD_MAX];
        u32                     dma_chan[SATA_DWC_QCMD_MAX];
        int                     dma_pending[SATA_DWC_QCMD_MAX];
};

/*
 * Commonly used DWC SATA driver Macros
 */
#define HSDEV_FROM_HOST(host)  ((struct sata_dwc_device *)\
                                        (host)->private_data)
#define HSDEV_FROM_AP(ap)  ((struct sata_dwc_device *)\
                                        (ap)->host->private_data)
#define HSDEVP_FROM_AP(ap)   ((struct sata_dwc_device_port *)\
                                        (ap)->private_data)
#define HSDEV_FROM_QC(qc)       ((struct sata_dwc_device *)\
                                        (qc)->ap->host->private_data)
#define HSDEV_FROM_HSDEVP(p)    ((struct sata_dwc_device *)\
                                                (hsdevp)->hsdev)

enum {
        SATA_DWC_CMD_ISSUED_NOT         = 0,
        SATA_DWC_CMD_ISSUED_PEND        = 1,
        SATA_DWC_CMD_ISSUED_EXEC        = 2,
        SATA_DWC_CMD_ISSUED_NODATA      = 3,

        SATA_DWC_DMA_PENDING_NONE       = 0,
        SATA_DWC_DMA_PENDING_TX         = 1,
        SATA_DWC_DMA_PENDING_RX         = 2,
};

struct sata_dwc_host_priv {
        void    __iomem  *scr_addr_sstatus;
        u32     sata_dwc_sactive_issued ;
        u32     sata_dwc_sactive_queued ;
        u32     dma_interrupt_count;
        struct  ahb_dma_regs    *sata_dma_regs;
        struct  device  *dwc_dev;
        int     dma_channel;
};
struct sata_dwc_host_priv host_pvt;
/*
 * Prototypes
 */
static void sata_dwc_bmdma_start_by_tag(struct ata_queued_cmd *qc, u8 tag);
static int sata_dwc_qc_complete(struct ata_port *ap, struct ata_queued_cmd *qc,
                                u32 check_status);
static void sata_dwc_dma_xfer_complete(struct ata_port *ap, u32 check_status);
static void sata_dwc_port_stop(struct ata_port *ap);
static void sata_dwc_clear_dmacr(struct sata_dwc_device_port *hsdevp, u8 tag);
static int dma_dwc_init(struct sata_dwc_device *hsdev, int irq);
static void dma_dwc_exit(struct sata_dwc_device *hsdev);
static int dma_dwc_xfer_setup(struct scatterlist *sg, int num_elems,
                              struct lli *lli, dma_addr_t dma_lli,
                              void __iomem *addr, int dir);
static void dma_dwc_xfer_start(int dma_ch);

static const char *get_prot_descript(u8 protocol)
{
        switch ((enum ata_tf_protocols)protocol) {
        case ATA_PROT_NODATA:
                return "ATA no data";
        case ATA_PROT_PIO:
                return "ATA PIO";
        case ATA_PROT_DMA:
                return "ATA DMA";
        case ATA_PROT_NCQ:
                return "ATA NCQ";
        case ATAPI_PROT_NODATA:
                return "ATAPI no data";
        case ATAPI_PROT_PIO:
                return "ATAPI PIO";
        case ATAPI_PROT_DMA:
                return "ATAPI DMA";
        default:
                return "unknown";
        }
}

static const char *get_dma_dir_descript(int dma_dir)
{
        switch ((enum dma_data_direction)dma_dir) {
        case DMA_BIDIRECTIONAL:
                return "bidirectional";
        case DMA_TO_DEVICE:
                return "to device";
        case DMA_FROM_DEVICE:
                return "from device";
        default:
                return "none";
        }
}

static void sata_dwc_tf_dump(struct ata_taskfile *tf)
{
        dev_vdbg(host_pvt.dwc_dev, "taskfile cmd: 0x%02x protocol: %s flags:"
                "0x%lx device: %x\n", tf->command,
                get_prot_descript(tf->protocol), tf->flags, tf->device);
        dev_vdbg(host_pvt.dwc_dev, "feature: 0x%02x nsect: 0x%x lbal: 0x%x "
                "lbam: 0x%x lbah: 0x%x\n", tf->feature, tf->nsect, tf->lbal,
                 tf->lbam, tf->lbah);
        dev_vdbg(host_pvt.dwc_dev, "hob_feature: 0x%02x hob_nsect: 0x%x "
                "hob_lbal: 0x%x hob_lbam: 0x%x hob_lbah: 0x%x\n",
                tf->hob_feature, tf->hob_nsect, tf->hob_lbal, tf->hob_lbam,
                tf->hob_lbah);
}

/*
 * Function: get_burst_length_encode
 * arguments: datalength: length in bytes of data
 * returns value to be programmed in register corresponding to data length
 * This value is effectively the log(base 2) of the length
 */
static  int get_burst_length_encode(int datalength)
{
        int items = datalength >> 2;    /* div by 4 to get lword count */

        if (items >= 64)
                return 5;

        if (items >= 32)
                return 4;

        if (items >= 16)
                return 3;

        if (items >= 8)
                return 2;

        if (items >= 4)
                return 1;

        return 0;
}

static  void clear_chan_interrupts(int c)
{
        out_le32(&(host_pvt.sata_dma_regs->interrupt_clear.tfr.low),
                 DMA_CHANNEL(c));
        out_le32(&(host_pvt.sata_dma_regs->interrupt_clear.block.low),
                 DMA_CHANNEL(c));
        out_le32(&(host_pvt.sata_dma_regs->interrupt_clear.srctran.low),
                 DMA_CHANNEL(c));
        out_le32(&(host_pvt.sata_dma_regs->interrupt_clear.dsttran.low),
                 DMA_CHANNEL(c));
        out_le32(&(host_pvt.sata_dma_regs->interrupt_clear.error.low),
                 DMA_CHANNEL(c));
}

/*
 * Function: dma_request_channel
 * arguments: None
 * returns channel number if available else -1
 * This function assigns the next available DMA channel from the list to the
 * requester
 */
static int dma_request_channel(void)
{
        /* Check if the channel is not currently in use */
        if (!(in_le32(&(host_pvt.sata_dma_regs->dma_chan_en.low)) &
                DMA_CHANNEL(host_pvt.dma_channel)))
                return host_pvt.dma_channel;
        dev_err(host_pvt.dwc_dev, "%s Channel %d is currently in use\n",
                __func__, host_pvt.dma_channel);
        return -1;
}

/*
 * Function: dma_dwc_interrupt
 * arguments: irq, dev_id, pt_regs
 * returns channel number if available else -1
 * Interrupt Handler for DW AHB SATA DMA
 */
static irqreturn_t dma_dwc_interrupt(int irq, void *hsdev_instance)
{
        int chan;
        u32 tfr_reg, err_reg;
        unsigned long flags;
        struct sata_dwc_device *hsdev =
                (struct sata_dwc_device *)hsdev_instance;
        struct ata_host *host = (struct ata_host *)hsdev->host;
        struct ata_port *ap;
        struct sata_dwc_device_port *hsdevp;
        u8 tag = 0;
        unsigned int port = 0;

        spin_lock_irqsave(&host->lock, flags);
        ap = host->ports[port];
        hsdevp = HSDEVP_FROM_AP(ap);
        tag = ap->link.active_tag;

        tfr_reg = in_le32(&(host_pvt.sata_dma_regs->interrupt_status.tfr\
                        .low));
        err_reg = in_le32(&(host_pvt.sata_dma_regs->interrupt_status.error\
                        .low));

        dev_dbg(ap->dev, "eot=0x%08x err=0x%08x pending=%d active port=%d\n",
                tfr_reg, err_reg, hsdevp->dma_pending[tag], port);

        chan = host_pvt.dma_channel;
        if (chan >= 0) {
                /* Check for end-of-transfer interrupt. */
                if (tfr_reg & DMA_CHANNEL(chan)) {
                        /*
                         * Each DMA command produces 2 interrupts.  Only
                         * complete the command after both interrupts have been
                         * seen. (See sata_dwc_isr())
                         */
                        host_pvt.dma_interrupt_count++;
                        sata_dwc_clear_dmacr(hsdevp, tag);

                        if (hsdevp->dma_pending[tag] ==
                            SATA_DWC_DMA_PENDING_NONE) {
                                dev_err(ap->dev, "DMA not pending eot=0x%08x "
                                        "err=0x%08x tag=0x%02x pending=%d\n",
                                        tfr_reg, err_reg, tag,
                                        hsdevp->dma_pending[tag]);
                        }

                        if ((host_pvt.dma_interrupt_count % 2) == 0)
                                sata_dwc_dma_xfer_complete(ap, 1);

                        /* Clear the interrupt */
                        out_le32(&(host_pvt.sata_dma_regs->interrupt_clear\
                                .tfr.low),
                                 DMA_CHANNEL(chan));
                }

                /* Check for error interrupt. */
                if (err_reg & DMA_CHANNEL(chan)) {
                        /* TODO Need error handler ! */
                        dev_err(ap->dev, "error interrupt err_reg=0x%08x\n",
                                err_reg);

                        /* Clear the interrupt. */
                        out_le32(&(host_pvt.sata_dma_regs->interrupt_clear\
                                .error.low),
                                 DMA_CHANNEL(chan));
                }
        }
        spin_unlock_irqrestore(&host->lock, flags);
        return IRQ_HANDLED;
}

/*
 * Function: dma_request_interrupts
 * arguments: hsdev
 * returns status
 * This function registers ISR for a particular DMA channel interrupt
 */
static int dma_request_interrupts(struct sata_dwc_device *hsdev, int irq)
{
        int retval = 0;
        int chan = host_pvt.dma_channel;

        if (chan >= 0) {
                /* Unmask error interrupt */
                out_le32(&(host_pvt.sata_dma_regs)->interrupt_mask.error.low,
                         DMA_ENABLE_CHAN(chan));

                /* Unmask end-of-transfer interrupt */
                out_le32(&(host_pvt.sata_dma_regs)->interrupt_mask.tfr.low,
                         DMA_ENABLE_CHAN(chan));
        }

        retval = request_irq(irq, dma_dwc_interrupt, 0, "SATA DMA", hsdev);
        if (retval) {
                dev_err(host_pvt.dwc_dev, "%s: could not get IRQ %d\n",
                __func__, irq);
                return -ENODEV;
        }

        /* Mark this interrupt as requested */
        hsdev->irq_dma = irq;
        return 0;
}

/*
 * Function: map_sg_to_lli
 * The Synopsis driver has a comment proposing that better performance
 * is possible by only enabling interrupts on the last item in the linked list.
 * However, it seems that could be a problem if an error happened on one of the
 * first items.  The transfer would halt, but no error interrupt would occur.
 * Currently this function sets interrupts enabled for each linked list item:
 * DMA_CTL_INT_EN.
 */
static int map_sg_to_lli(struct scatterlist *sg, int num_elems,
                        struct lli *lli, dma_addr_t dma_lli,
                        void __iomem *dmadr_addr, int dir)
{
        int i, idx = 0;
        int fis_len = 0;
        dma_addr_t next_llp;
        int bl;
        int sms_val, dms_val;

        sms_val = 0;
        dms_val = 1 + host_pvt.dma_channel;
        dev_dbg(host_pvt.dwc_dev, "%s: sg=%p nelem=%d lli=%p dma_lli=0x%08x"
                " dmadr=0x%08x\n", __func__, sg, num_elems, lli, (u32)dma_lli,
                (u32)dmadr_addr);

        bl = get_burst_length_encode(AHB_DMA_BRST_DFLT);

        for (i = 0; i < num_elems; i++, sg++) {
                u32 addr, offset;
                u32 sg_len, len;

                addr = (u32) sg_dma_address(sg);
                sg_len = sg_dma_len(sg);

                dev_dbg(host_pvt.dwc_dev, "%s: elem=%d sg_addr=0x%x sg_len"
                        "=%d\n", __func__, i, addr, sg_len);

                while (sg_len) {
                        if (idx >= SATA_DWC_DMAC_LLI_NUM) {
                                /* The LLI table is not large enough. */
                                dev_err(host_pvt.dwc_dev, "LLI table overrun "
                                "(idx=%d)\n", idx);
                                break;
                        }
                        len = (sg_len > SATA_DWC_DMAC_CTRL_TSIZE_MAX) ?
                                SATA_DWC_DMAC_CTRL_TSIZE_MAX : sg_len;

                        offset = addr & 0xffff;
                        if ((offset + sg_len) > 0x10000)
                                len = 0x10000 - offset;

                        /*
                         * Make sure a LLI block is not created that will span
                         * 8K max FIS boundary.  If the block spans such a FIS
                         * boundary, there is a chance that a DMA burst will
                         * cross that boundary -- this results in an error in
                         * the host controller.
                         */
                        if (fis_len + len > 8192) {
                                dev_dbg(host_pvt.dwc_dev, "SPLITTING: fis_len="
                                        "%d(0x%x) len=%d(0x%x)\n", fis_len,
                                         fis_len, len, len);
                                len = 8192 - fis_len;
                                fis_len = 0;
                        } else {
                                fis_len += len;
                        }
                        if (fis_len == 8192)
                                fis_len = 0;

                        /*
                         * Set DMA addresses and lower half of control register
                         * based on direction.
                         */
                        if (dir == DMA_FROM_DEVICE) {
                                lli[idx].dar = cpu_to_le32(addr);
                                lli[idx].sar = cpu_to_le32((u32)dmadr_addr);

                                lli[idx].ctl.low = cpu_to_le32(
                                        DMA_CTL_TTFC(DMA_CTL_TTFC_P2M_DMAC) |
                                        DMA_CTL_SMS(sms_val) |
                                        DMA_CTL_DMS(dms_val) |
                                        DMA_CTL_SRC_MSIZE(bl) |
                                        DMA_CTL_DST_MSIZE(bl) |
                                        DMA_CTL_SINC_NOCHANGE |
                                        DMA_CTL_SRC_TRWID(2) |
                                        DMA_CTL_DST_TRWID(2) |
                                        DMA_CTL_INT_EN |
                                        DMA_CTL_LLP_SRCEN |
                                        DMA_CTL_LLP_DSTEN);
                        } else {        /* DMA_TO_DEVICE */
                                lli[idx].sar = cpu_to_le32(addr);
                                lli[idx].dar = cpu_to_le32((u32)dmadr_addr);

                                lli[idx].ctl.low = cpu_to_le32(
                                        DMA_CTL_TTFC(DMA_CTL_TTFC_M2P_PER) |
                                        DMA_CTL_SMS(dms_val) |
                                        DMA_CTL_DMS(sms_val) |
                                        DMA_CTL_SRC_MSIZE(bl) |
                                        DMA_CTL_DST_MSIZE(bl) |
                                        DMA_CTL_DINC_NOCHANGE |
                                        DMA_CTL_SRC_TRWID(2) |
                                        DMA_CTL_DST_TRWID(2) |
                                        DMA_CTL_INT_EN |
                                        DMA_CTL_LLP_SRCEN |
                                        DMA_CTL_LLP_DSTEN);
                        }

                        dev_dbg(host_pvt.dwc_dev, "%s setting ctl.high len: "
                                "0x%08x val: 0x%08x\n", __func__,
                                len, DMA_CTL_BLK_TS(len / 4));

                        /* Program the LLI CTL high register */
                        lli[idx].ctl.high = cpu_to_le32(DMA_CTL_BLK_TS\
                                                (len / 4));

                        /* Program the next pointer.  The next pointer must be
                         * the physical address, not the virtual address.
                         */
                        next_llp = (dma_lli + ((idx + 1) * sizeof(struct \
                                                        lli)));

                        /* The last 2 bits encode the list master select. */
                        next_llp = DMA_LLP_LMS(next_llp, DMA_LLP_AHBMASTER2);

                        lli[idx].llp = cpu_to_le32(next_llp);
                        idx++;
                        sg_len -= len;
                        addr += len;
                }
        }

        /*
         * The last next ptr has to be zero and the last control low register
         * has to have LLP_SRC_EN and LLP_DST_EN (linked list pointer source
         * and destination enable) set back to 0 (disabled.) This is what tells
         * the core that this is the last item in the linked list.
         */
        if (idx) {
                lli[idx-1].llp = 0x00000000;
                lli[idx-1].ctl.low &= DMA_CTL_LLP_DISABLE_LE32;

                /* Flush cache to memory */
                dma_cache_sync(NULL, lli, (sizeof(struct lli) * idx),
                               DMA_BIDIRECTIONAL);
        }

        return idx;
}

/*
 * Function: dma_dwc_xfer_start
 * arguments: Channel number
 * Return : None
 * Enables the DMA channel
 */
static void dma_dwc_xfer_start(int dma_ch)
{
        /* Enable the DMA channel */
        out_le32(&(host_pvt.sata_dma_regs->dma_chan_en.low),
                 in_le32(&(host_pvt.sata_dma_regs->dma_chan_en.low)) |
                 DMA_ENABLE_CHAN(dma_ch));
}

static int dma_dwc_xfer_setup(struct scatterlist *sg, int num_elems,
                              struct lli *lli, dma_addr_t dma_lli,
                              void __iomem *addr, int dir)
{
        int dma_ch;
        int num_lli;
        /* Acquire DMA channel */
        dma_ch = dma_request_channel();
        if (dma_ch == -1) {
                dev_err(host_pvt.dwc_dev, "%s: dma channel unavailable\n",
                         __func__);
                return -EAGAIN;
        }

        /* Convert SG list to linked list of items (LLIs) for AHB DMA */
        num_lli = map_sg_to_lli(sg, num_elems, lli, dma_lli, addr, dir);

        dev_dbg(host_pvt.dwc_dev, "%s sg: 0x%p, count: %d lli: %p dma_lli:"
                " 0x%0xlx addr: %p lli count: %d\n", __func__, sg, num_elems,
                 lli, (u32)dma_lli, addr, num_lli);

        clear_chan_interrupts(dma_ch);

        /* Program the CFG register. */
        out_le32(&(host_pvt.sata_dma_regs->chan_regs[dma_ch].cfg.high),
                 DMA_CFG_HW_HS_SRC(dma_ch) | DMA_CFG_HW_HS_DEST(dma_ch) |
                 DMA_CFG_PROTCTL | DMA_CFG_FCMOD_REQ);
        out_le32(&(host_pvt.sata_dma_regs->chan_regs[dma_ch].cfg.low),
                 DMA_CFG_HW_CH_PRIOR(dma_ch));

        /* Program the address of the linked list */
        out_le32(&(host_pvt.sata_dma_regs->chan_regs[dma_ch].llp.low),
                 DMA_LLP_LMS(dma_lli, DMA_LLP_AHBMASTER2));

        /* Program the CTL register with src enable / dst enable */
        out_le32(&(host_pvt.sata_dma_regs->chan_regs[dma_ch].ctl.low),
                 DMA_CTL_LLP_SRCEN | DMA_CTL_LLP_DSTEN);
        return dma_ch;
}

/*
 * Function: dma_dwc_exit
 * arguments: None
 * returns status
 * This function exits the SATA DMA driver
 */
static void dma_dwc_exit(struct sata_dwc_device *hsdev)
{
        dev_dbg(host_pvt.dwc_dev, "%s:\n", __func__);
        if (host_pvt.sata_dma_regs) {
                iounmap(host_pvt.sata_dma_regs);
                host_pvt.sata_dma_regs = NULL;
        }

        if (hsdev->irq_dma) {
                free_irq(hsdev->irq_dma, hsdev);
                hsdev->irq_dma = 0;
        }
}

/*
 * Function: dma_dwc_init
 * arguments: hsdev
 * returns status
 * This function initializes the SATA DMA driver
 */
static int dma_dwc_init(struct sata_dwc_device *hsdev, int irq)
{
        int err;

        err = dma_request_interrupts(hsdev, irq);
        if (err) {
                dev_err(host_pvt.dwc_dev, "%s: dma_request_interrupts returns"
                        " %d\n", __func__, err);
                goto error_out;
        }

        /* Enabe DMA */
        out_le32(&(host_pvt.sata_dma_regs->dma_cfg.low), DMA_EN);

        dev_notice(host_pvt.dwc_dev, "DMA initialized\n");
        dev_dbg(host_pvt.dwc_dev, "SATA DMA registers=0x%p\n", host_pvt.\
                sata_dma_regs);

        return 0;

error_out:
        dma_dwc_exit(hsdev);

        return err;
}

static int sata_dwc_scr_read(struct ata_link *link, unsigned int scr, u32 *val)
{
        if (scr > SCR_NOTIFICATION) {
                dev_err(link->ap->dev, "%s: Incorrect SCR offset 0x%02x\n",
                        __func__, scr);
                return -EINVAL;
        }

        *val = in_le32((void *)link->ap->ioaddr.scr_addr + (scr * 4));
        dev_dbg(link->ap->dev, "%s: id=%d reg=%d val=val=0x%08x\n",
                __func__, link->ap->print_id, scr, *val);

        return 0;
}

static int sata_dwc_scr_write(struct ata_link *link, unsigned int scr, u32 val)
{
        dev_dbg(link->ap->dev, "%s: id=%d reg=%d val=val=0x%08x\n",
                __func__, link->ap->print_id, scr, val);
        if (scr > SCR_NOTIFICATION) {
                dev_err(link->ap->dev, "%s: Incorrect SCR offset 0x%02x\n",
                         __func__, scr);
                return -EINVAL;
        }
        out_le32((void *)link->ap->ioaddr.scr_addr + (scr * 4), val);

        return 0;
}

static u32 core_scr_read(unsigned int scr)
{
        return in_le32((void __iomem *)(host_pvt.scr_addr_sstatus) +\
                        (scr * 4));
}

static void core_scr_write(unsigned int scr, u32 val)
{
        out_le32((void __iomem *)(host_pvt.scr_addr_sstatus) + (scr * 4),
                val);
}

static void clear_serror(void)
{
        u32 val;
        val = core_scr_read(SCR_ERROR);
        core_scr_write(SCR_ERROR, val);

}

static void clear_interrupt_bit(struct sata_dwc_device *hsdev, u32 bit)
{
        out_le32(&hsdev->sata_dwc_regs->intpr,
                 in_le32(&hsdev->sata_dwc_regs->intpr));
}

static u32 qcmd_tag_to_mask(u8 tag)
{
        return 0x00000001 << (tag & 0x1f);
}

/* See ahci.c */
static void sata_dwc_error_intr(struct ata_port *ap,
                                struct sata_dwc_device *hsdev, uint intpr)
{
        struct sata_dwc_device_port *hsdevp = HSDEVP_FROM_AP(ap);
        struct ata_eh_info *ehi = &ap->link.eh_info;
        unsigned int err_mask = 0, action = 0;
        struct ata_queued_cmd *qc;
        u32 serror;
        u8 status, tag;
        u32 err_reg;

        ata_ehi_clear_desc(ehi);

        serror = core_scr_read(SCR_ERROR);
        status = ap->ops->sff_check_status(ap);

        err_reg = in_le32(&(host_pvt.sata_dma_regs->interrupt_status.error.\
                        low));
        tag = ap->link.active_tag;

        dev_err(ap->dev, "%s SCR_ERROR=0x%08x intpr=0x%08x status=0x%08x "
                "dma_intp=%d pending=%d issued=%d dma_err_status=0x%08x\n",
                __func__, serror, intpr, status, host_pvt.dma_interrupt_count,
                hsdevp->dma_pending[tag], hsdevp->cmd_issued[tag], err_reg);

        /* Clear error register and interrupt bit */
        clear_serror();
        clear_interrupt_bit(hsdev, SATA_DWC_INTPR_ERR);

        /* This is the only error happening now.  TODO check for exact error */

        err_mask |= AC_ERR_HOST_BUS;
        action |= ATA_EH_RESET;

        /* Pass this on to EH */
        ehi->serror |= serror;
        ehi->action |= action;

        qc = ata_qc_from_tag(ap, tag);
        if (qc)
                qc->err_mask |= err_mask;
        else
                ehi->err_mask |= err_mask;

        ata_port_abort(ap);
}

/*
 * Function : sata_dwc_isr
 * arguments : irq, void *dev_instance, struct pt_regs *regs
 * Return value : irqreturn_t - status of IRQ
 * This Interrupt handler called via port ops registered function.
 * .irq_handler = sata_dwc_isr
 */
static irqreturn_t sata_dwc_isr(int irq, void *dev_instance)
{
        struct ata_host *host = (struct ata_host *)dev_instance;
        struct sata_dwc_device *hsdev = HSDEV_FROM_HOST(host);
        struct ata_port *ap;
        struct ata_queued_cmd *qc;
        unsigned long flags;
        u8 status, tag;
        int handled, num_processed, port = 0;
        uint intpr, sactive, sactive2, tag_mask;
        struct sata_dwc_device_port *hsdevp;
        host_pvt.sata_dwc_sactive_issued = 0;

        spin_lock_irqsave(&host->lock, flags);

        /* Read the interrupt register */
        intpr = in_le32(&hsdev->sata_dwc_regs->intpr);

        ap = host->ports[port];
        hsdevp = HSDEVP_FROM_AP(ap);

        dev_dbg(ap->dev, "%s intpr=0x%08x active_tag=%d\n", __func__, intpr,
                ap->link.active_tag);

        /* Check for error interrupt */
        if (intpr & SATA_DWC_INTPR_ERR) {
                sata_dwc_error_intr(ap, hsdev, intpr);
                handled = 1;
                goto DONE;
        }

        /* Check for DMA SETUP FIS (FP DMA) interrupt */
        if (intpr & SATA_DWC_INTPR_NEWFP) {
                clear_interrupt_bit(hsdev, SATA_DWC_INTPR_NEWFP);

                tag = (u8)(in_le32(&hsdev->sata_dwc_regs->fptagr));
                dev_dbg(ap->dev, "%s: NEWFP tag=%d\n", __func__, tag);
                if (hsdevp->cmd_issued[tag] != SATA_DWC_CMD_ISSUED_PEND)
                        dev_warn(ap->dev, "CMD tag=%d not pending?\n", tag);

                host_pvt.sata_dwc_sactive_issued |= qcmd_tag_to_mask(tag);

                qc = ata_qc_from_tag(ap, tag);
                /*
                 * Start FP DMA for NCQ command.  At this point the tag is the
                 * active tag.  It is the tag that matches the command about to
                 * be completed.
                 */
                qc->ap->link.active_tag = tag;
                sata_dwc_bmdma_start_by_tag(qc, tag);

                handled = 1;
                goto DONE;
        }
        sactive = core_scr_read(SCR_ACTIVE);
        tag_mask = (host_pvt.sata_dwc_sactive_issued | sactive) ^ sactive;

        /* If no sactive issued and tag_mask is zero then this is not NCQ */
        if (host_pvt.sata_dwc_sactive_issued == 0 && tag_mask == 0) {
                if (ap->link.active_tag == ATA_TAG_POISON)
                        tag = 0;
                else
                        tag = ap->link.active_tag;
                qc = ata_qc_from_tag(ap, tag);

                /* DEV interrupt w/ no active qc? */
                if (unlikely(!qc || (qc->tf.flags & ATA_TFLAG_POLLING))) {

                        dev_err(ap->dev, "%s interrupt with no active qc "
                                "qc=%p\n", __func__, qc);
                        ap->ops->sff_check_status(ap);
                        handled = 1;
                        goto DONE;
                }
                status = ap->ops->sff_check_status(ap);

                qc->ap->link.active_tag = tag;
                hsdevp->cmd_issued[tag] = SATA_DWC_CMD_ISSUED_NOT;

                if (status & ATA_ERR) {
                        dev_dbg(ap->dev, "interrupt ATA_ERR (0x%x)\n", status);
                        sata_dwc_qc_complete(ap, qc, 1);
                        handled = 1;
                        goto DONE;
                }

                dev_dbg(ap->dev, "%s non-NCQ cmd interrupt, protocol: %s\n",
                        __func__, get_prot_descript(qc->tf.protocol));
DRVSTILLBUSY:
                if (ata_is_dma(qc->tf.protocol)) {
                        /*
                         * Each DMA transaction produces 2 interrupts. The DMAC
                         * transfer complete interrupt and the SATA controller
                         * operation done interrupt. The command should be
                         * completed only after both interrupts are seen.
                         */
                        host_pvt.dma_interrupt_count++;
                        if (hsdevp->dma_pending[tag] == \
                                        SATA_DWC_DMA_PENDING_NONE) {
                                dev_err(ap->dev, "%s: DMA not pending "
                                        "intpr=0x%08x status=0x%08x pending"
                                        "=%d\n", __func__, intpr, status,
                                        hsdevp->dma_pending[tag]);
                        }

                        if ((host_pvt.dma_interrupt_count % 2) == 0)
                                sata_dwc_dma_xfer_complete(ap, 1);
                } else if (ata_is_pio(qc->tf.protocol)) {
                        ata_sff_hsm_move(ap, qc, status, 0);
                        handled = 1;
                        goto DONE;
                } else {
                        if (unlikely(sata_dwc_qc_complete(ap, qc, 1)))
                                goto DRVSTILLBUSY;
                }

                handled = 1;
                goto DONE;
        }

        /*
         * This is a NCQ command. At this point we need to figure out for which
         * tags we have gotten a completion interrupt.  One interrupt may serve
         * as completion for more than one operation when commands are queued
         * (NCQ).  We need to process each completed command.
         */

         /* process completed commands */
        sactive = core_scr_read(SCR_ACTIVE);
        tag_mask = (host_pvt.sata_dwc_sactive_issued | sactive) ^ sactive;

        if (sactive != 0 || (host_pvt.sata_dwc_sactive_issued) > 1 || \
                                                        tag_mask > 1) {
                dev_dbg(ap->dev, "%s NCQ:sactive=0x%08x  sactive_issued=0x%08x"
                        "tag_mask=0x%08x\n", __func__, sactive,
                        host_pvt.sata_dwc_sactive_issued, tag_mask);
        }

        if ((tag_mask | (host_pvt.sata_dwc_sactive_issued)) != \
                                        (host_pvt.sata_dwc_sactive_issued)) {
                dev_warn(ap->dev, "Bad tag mask?  sactive=0x%08x "
                         "(host_pvt.sata_dwc_sactive_issued)=0x%08x  tag_mask"
                         "=0x%08x\n", sactive, host_pvt.sata_dwc_sactive_issued,
                          tag_mask);
        }

        /* read just to clear ... not bad if currently still busy */
        status = ap->ops->sff_check_status(ap);
        dev_dbg(ap->dev, "%s ATA status register=0x%x\n", __func__, status);

        tag = 0;
        num_processed = 0;
        while (tag_mask) {
                num_processed++;
                while (!(tag_mask & 0x00000001)) {
                        tag++;
                        tag_mask <<= 1;
                }

                tag_mask &= (~0x00000001);
                qc = ata_qc_from_tag(ap, tag);

                /* To be picked up by completion functions */
                qc->ap->link.active_tag = tag;
                hsdevp->cmd_issued[tag] = SATA_DWC_CMD_ISSUED_NOT;

                /* Let libata/scsi layers handle error */
                if (status & ATA_ERR) {
                        dev_dbg(ap->dev, "%s ATA_ERR (0x%x)\n", __func__,
                                status);
                        sata_dwc_qc_complete(ap, qc, 1);
                        handled = 1;
                        goto DONE;
                }

                /* Process completed command */
                dev_dbg(ap->dev, "%s NCQ command, protocol: %s\n", __func__,
                        get_prot_descript(qc->tf.protocol));
                if (ata_is_dma(qc->tf.protocol)) {
                        host_pvt.dma_interrupt_count++;
                        if (hsdevp->dma_pending[tag] == \
                                        SATA_DWC_DMA_PENDING_NONE)
                                dev_warn(ap->dev, "%s: DMA not pending?\n",
                                        __func__);
                        if ((host_pvt.dma_interrupt_count % 2) == 0)
                                sata_dwc_dma_xfer_complete(ap, 1);
                } else {
                        if (unlikely(sata_dwc_qc_complete(ap, qc, 1)))
                                goto STILLBUSY;
                }
                continue;

STILLBUSY:
                ap->stats.idle_irq++;
                dev_warn(ap->dev, "STILL BUSY IRQ ata%d: irq trap\n",
                        ap->print_id);
        } /* while tag_mask */

        /*
         * Check to see if any commands completed while we were processing our
         * initial set of completed commands (read status clears interrupts,
         * so we might miss a completed command interrupt if one came in while
         * we were processing --we read status as part of processing a completed
         * command).
         */
        sactive2 = core_scr_read(SCR_ACTIVE);
        if (sactive2 != sactive) {
                dev_dbg(ap->dev, "More completed - sactive=0x%x sactive2"
                        "=0x%x\n", sactive, sactive2);
        }
        handled = 1;

DONE:
        spin_unlock_irqrestore(&host->lock, flags);
        return IRQ_RETVAL(handled);
}

static void sata_dwc_clear_dmacr(struct sata_dwc_device_port *hsdevp, u8 tag)
{
        struct sata_dwc_device *hsdev = HSDEV_FROM_HSDEVP(hsdevp);

        if (hsdevp->dma_pending[tag] == SATA_DWC_DMA_PENDING_RX) {
                out_le32(&(hsdev->sata_dwc_regs->dmacr),
                         SATA_DWC_DMACR_RX_CLEAR(
                                 in_le32(&(hsdev->sata_dwc_regs->dmacr))));
        } else if (hsdevp->dma_pending[tag] == SATA_DWC_DMA_PENDING_TX) {
                out_le32(&(hsdev->sata_dwc_regs->dmacr),
                         SATA_DWC_DMACR_TX_CLEAR(
                                 in_le32(&(hsdev->sata_dwc_regs->dmacr))));
        } else {
                /*
                 * This should not happen, it indicates the driver is out of
                 * sync.  If it does happen, clear dmacr anyway.
                 */
                dev_err(host_pvt.dwc_dev, "%s DMA protocol RX and"
                        "TX DMA not pending tag=0x%02x pending=%d"
                        " dmacr: 0x%08x\n", __func__, tag,
                        hsdevp->dma_pending[tag],
                        in_le32(&(hsdev->sata_dwc_regs->dmacr)));
                out_le32(&(hsdev->sata_dwc_regs->dmacr),
                        SATA_DWC_DMACR_TXRXCH_CLEAR);
        }
}

static void sata_dwc_dma_xfer_complete(struct ata_port *ap, u32 check_status)
{
        struct ata_queued_cmd *qc;
        struct sata_dwc_device_port *hsdevp = HSDEVP_FROM_AP(ap);
        struct sata_dwc_device *hsdev = HSDEV_FROM_AP(ap);
        u8 tag = 0;

        tag = ap->link.active_tag;
        qc = ata_qc_from_tag(ap, tag);
        if (!qc) {
                dev_err(ap->dev, "failed to get qc");
                return;
        }

#ifdef DEBUG_NCQ
        if (tag > 0) {
                dev_info(ap->dev, "%s tag=%u cmd=0x%02x dma dir=%s proto=%s "
                         "dmacr=0x%08x\n", __func__, qc->tag, qc->tf.command,
                         get_dma_dir_descript(qc->dma_dir),
                         get_prot_descript(qc->tf.protocol),
                         in_le32(&(hsdev->sata_dwc_regs->dmacr)));
        }
#endif

        if (ata_is_dma(qc->tf.protocol)) {
                if (hsdevp->dma_pending[tag] == SATA_DWC_DMA_PENDING_NONE) {
                        dev_err(ap->dev, "%s DMA protocol RX and TX DMA not "
                                "pending dmacr: 0x%08x\n", __func__,
                                in_le32(&(hsdev->sata_dwc_regs->dmacr)));
                }

                hsdevp->dma_pending[tag] = SATA_DWC_DMA_PENDING_NONE;
                sata_dwc_qc_complete(ap, qc, check_status);
                ap->link.active_tag = ATA_TAG_POISON;
        } else {
                sata_dwc_qc_complete(ap, qc, check_status);
        }
}

static int sata_dwc_qc_complete(struct ata_port *ap, struct ata_queued_cmd *qc,
                                u32 check_status)
{
        u8 status = 0;
        u32 mask = 0x0;
        u8 tag = qc->tag;
        struct sata_dwc_device_port *hsdevp = HSDEVP_FROM_AP(ap);
        host_pvt.sata_dwc_sactive_queued = 0;
        dev_dbg(ap->dev, "%s checkstatus? %x\n", __func__, check_status);

        if (hsdevp->dma_pending[tag] == SATA_DWC_DMA_PENDING_TX)
                dev_err(ap->dev, "TX DMA PENDING\n");
        else if (hsdevp->dma_pending[tag] == SATA_DWC_DMA_PENDING_RX)
                dev_err(ap->dev, "RX DMA PENDING\n");
        dev_dbg(ap->dev, "QC complete cmd=0x%02x status=0x%02x ata%u:"
                " protocol=%d\n", qc->tf.command, status, ap->print_id,
                 qc->tf.protocol);

        /* clear active bit */
        mask = (~(qcmd_tag_to_mask(tag)));
        host_pvt.sata_dwc_sactive_queued = (host_pvt.sata_dwc_sactive_queued) \
                                                & mask;
        host_pvt.sata_dwc_sactive_issued = (host_pvt.sata_dwc_sactive_issued) \
                                                & mask;
        ata_qc_complete(qc);
        return 0;
}

static void sata_dwc_enable_interrupts(struct sata_dwc_device *hsdev)
{
        /* Enable selective interrupts by setting the interrupt maskregister*/
        out_le32(&hsdev->sata_dwc_regs->intmr,
                 SATA_DWC_INTMR_ERRM |
                 SATA_DWC_INTMR_NEWFPM |
                 SATA_DWC_INTMR_PMABRTM |
                 SATA_DWC_INTMR_DMATM);
        /*
         * Unmask the error bits that should trigger an error interrupt by
         * setting the error mask register.
         */
        out_le32(&hsdev->sata_dwc_regs->errmr, SATA_DWC_SERROR_ERR_BITS);

        dev_dbg(host_pvt.dwc_dev, "%s: INTMR = 0x%08x, ERRMR = 0x%08x\n",
                 __func__, in_le32(&hsdev->sata_dwc_regs->intmr),
                in_le32(&hsdev->sata_dwc_regs->errmr));
}

static void sata_dwc_setup_port(struct ata_ioports *port, unsigned long base)
{
        port->cmd_addr = (void *)base + 0x00;
        port->data_addr = (void *)base + 0x00;

        port->error_addr = (void *)base + 0x04;
        port->feature_addr = (void *)base + 0x04;

        port->nsect_addr = (void *)base + 0x08;

        port->lbal_addr = (void *)base + 0x0c;
        port->lbam_addr = (void *)base + 0x10;
        port->lbah_addr = (void *)base + 0x14;

        port->device_addr = (void *)base + 0x18;
        port->command_addr = (void *)base + 0x1c;
        port->status_addr = (void *)base + 0x1c;

        port->altstatus_addr = (void *)base + 0x20;
        port->ctl_addr = (void *)base + 0x20;
}

/*
 * Function : sata_dwc_port_start
 * arguments : struct ata_ioports *port
 * Return value : returns 0 if success, error code otherwise
 * This function allocates the scatter gather LLI table for AHB DMA
 */
static int sata_dwc_port_start(struct ata_port *ap)
{
        int err = 0;
        struct sata_dwc_device *hsdev;
        struct sata_dwc_device_port *hsdevp = NULL;
        struct device *pdev;
        int i;

        hsdev = HSDEV_FROM_AP(ap);

        dev_dbg(ap->dev, "%s: port_no=%d\n", __func__, ap->port_no);

        hsdev->host = ap->host;
        pdev = ap->host->dev;
        if (!pdev) {
                dev_err(ap->dev, "%s: no ap->host->dev\n", __func__);
                err = -ENODEV;
                goto CLEANUP;
        }

        /* Allocate Port Struct */
        hsdevp = kzalloc(sizeof(*hsdevp), GFP_KERNEL);
        if (!hsdevp) {
                dev_err(ap->dev, "%s: kmalloc failed for hsdevp\n", __func__);
                err = -ENOMEM;
                goto CLEANUP;
        }
        hsdevp->hsdev = hsdev;

        for (i = 0; i < SATA_DWC_QCMD_MAX; i++)
                hsdevp->cmd_issued[i] = SATA_DWC_CMD_ISSUED_NOT;

        ap->bmdma_prd = 0;      /* set these so libata doesn't use them */
        ap->bmdma_prd_dma = 0;

        /*
         * DMA - Assign scatter gather LLI table. We can't use the libata
         * version since it's PRD is IDE PCI specific.
         */
        for (i = 0; i < SATA_DWC_QCMD_MAX; i++) {
                hsdevp->llit[i] = dma_alloc_coherent(pdev,
                                                     SATA_DWC_DMAC_LLI_TBL_SZ,
                                                     &(hsdevp->llit_dma[i]),
                                                     GFP_ATOMIC);
                if (!hsdevp->llit[i]) {
                        dev_err(ap->dev, "%s: dma_alloc_coherent failed\n",
                                 __func__);
                        err = -ENOMEM;
                        goto CLEANUP_ALLOC;
                }
        }

        if (ap->port_no == 0)  {
                dev_dbg(ap->dev, "%s: clearing TXCHEN, RXCHEN in DMAC\n",
                        __func__);
                out_le32(&hsdev->sata_dwc_regs->dmacr,
                         SATA_DWC_DMACR_TXRXCH_CLEAR);

                dev_dbg(ap->dev, "%s: setting burst size in DBTSR\n",
                         __func__);
                out_le32(&hsdev->sata_dwc_regs->dbtsr,
                         (SATA_DWC_DBTSR_MWR(AHB_DMA_BRST_DFLT) |
                          SATA_DWC_DBTSR_MRD(AHB_DMA_BRST_DFLT)));
        }

        /* Clear any error bits before libata starts issuing commands */
        clear_serror();
        ap->private_data = hsdevp;
        dev_dbg(ap->dev, "%s: done\n", __func__);
        return 0;

CLEANUP_ALLOC:
        kfree(hsdevp);
CLEANUP:
        dev_dbg(ap->dev, "%s: fail. ap->id = %d\n", __func__, ap->print_id);
        return err;
}

static void sata_dwc_port_stop(struct ata_port *ap)
{
        int i;
        struct sata_dwc_device *hsdev = HSDEV_FROM_AP(ap);
        struct sata_dwc_device_port *hsdevp = HSDEVP_FROM_AP(ap);

        dev_dbg(ap->dev, "%s: ap->id = %d\n", __func__, ap->print_id);

        if (hsdevp && hsdev) {
                /* deallocate LLI table */
                for (i = 0; i < SATA_DWC_QCMD_MAX; i++) {
                        dma_free_coherent(ap->host->dev,
                                          SATA_DWC_DMAC_LLI_TBL_SZ,
                                         hsdevp->llit[i], hsdevp->llit_dma[i]);
                }

                kfree(hsdevp);
        }
        ap->private_data = NULL;
}

/*
 * Function : sata_dwc_exec_command_by_tag
 * arguments : ata_port *ap, ata_taskfile *tf, u8 tag, u32 cmd_issued
 * Return value : None
 * This function keeps track of individual command tag ids and calls
 * ata_exec_command in libata
 */
static void sata_dwc_exec_command_by_tag(struct ata_port *ap,
                                         struct ata_taskfile *tf,
                                         u8 tag, u32 cmd_issued)
{
        unsigned long flags;
        struct sata_dwc_device_port *hsdevp = HSDEVP_FROM_AP(ap);

        dev_dbg(ap->dev, "%s cmd(0x%02x): %s tag=%d\n", __func__, tf->command,
                ata_get_cmd_descript(tf->command), tag);

        spin_lock_irqsave(&ap->host->lock, flags);
        hsdevp->cmd_issued[tag] = cmd_issued;
        spin_unlock_irqrestore(&ap->host->lock, flags);
        /*
         * Clear SError before executing a new command.
         * sata_dwc_scr_write and read can not be used here. Clearing the PM
         * managed SError register for the disk needs to be done before the
         * task file is loaded.
         */
        clear_serror();
        ata_sff_exec_command(ap, tf);
}

static void sata_dwc_bmdma_setup_by_tag(struct ata_queued_cmd *qc, u8 tag)
{
        sata_dwc_exec_command_by_tag(qc->ap, &qc->tf, tag,
                                     SATA_DWC_CMD_ISSUED_PEND);
}

static void sata_dwc_bmdma_setup(struct ata_queued_cmd *qc)
{
        u8 tag = qc->tag;

        if (ata_is_ncq(qc->tf.protocol)) {
                dev_dbg(qc->ap->dev, "%s: ap->link.sactive=0x%08x tag=%d\n",
                        __func__, qc->ap->link.sactive, tag);
        } else {
                tag = 0;
        }
        sata_dwc_bmdma_setup_by_tag(qc, tag);
}

static void sata_dwc_bmdma_start_by_tag(struct ata_queued_cmd *qc, u8 tag)
{
        int start_dma;
        u32 reg, dma_chan;
        struct sata_dwc_device *hsdev = HSDEV_FROM_QC(qc);
        struct ata_port *ap = qc->ap;
        struct sata_dwc_device_port *hsdevp = HSDEVP_FROM_AP(ap);
        int dir = qc->dma_dir;
        dma_chan = hsdevp->dma_chan[tag];

        if (hsdevp->cmd_issued[tag] != SATA_DWC_CMD_ISSUED_NOT) {
                start_dma = 1;
                if (dir == DMA_TO_DEVICE)
                        hsdevp->dma_pending[tag] = SATA_DWC_DMA_PENDING_TX;
                else
                        hsdevp->dma_pending[tag] = SATA_DWC_DMA_PENDING_RX;
        } else {
                dev_err(ap->dev, "%s: Command not pending cmd_issued=%d "
                        "(tag=%d) DMA NOT started\n", __func__,
                        hsdevp->cmd_issued[tag], tag);
                start_dma = 0;
        }

        dev_dbg(ap->dev, "%s qc=%p tag: %x cmd: 0x%02x dma_dir: %s "
                "start_dma? %x\n", __func__, qc, tag, qc->tf.command,
                get_dma_dir_descript(qc->dma_dir), start_dma);
        sata_dwc_tf_dump(&(qc->tf));

        if (start_dma) {
                reg = core_scr_read(SCR_ERROR);
                if (reg & SATA_DWC_SERROR_ERR_BITS) {
                        dev_err(ap->dev, "%s: ****** SError=0x%08x ******\n",
                                __func__, reg);
                }

                if (dir == DMA_TO_DEVICE)
                        out_le32(&hsdev->sata_dwc_regs->dmacr,
                                SATA_DWC_DMACR_TXCHEN);
                else
                        out_le32(&hsdev->sata_dwc_regs->dmacr,
                                SATA_DWC_DMACR_RXCHEN);

                /* Enable AHB DMA transfer on the specified channel */
                dma_dwc_xfer_start(dma_chan);
        }
}

static void sata_dwc_bmdma_start(struct ata_queued_cmd *qc)
{
        u8 tag = qc->tag;

        if (ata_is_ncq(qc->tf.protocol)) {
                dev_dbg(qc->ap->dev, "%s: ap->link.sactive=0x%08x tag=%d\n",
                        __func__, qc->ap->link.sactive, tag);
        } else {
                tag = 0;
        }
        dev_dbg(qc->ap->dev, "%s\n", __func__);
        sata_dwc_bmdma_start_by_tag(qc, tag);
}

/*
 * Function : sata_dwc_qc_prep_by_tag
 * arguments : ata_queued_cmd *qc, u8 tag
 * Return value : None
 * qc_prep for a particular queued command based on tag
 */
static void sata_dwc_qc_prep_by_tag(struct ata_queued_cmd *qc, u8 tag)
{
        struct scatterlist *sg = qc->sg;
        struct ata_port *ap = qc->ap;
        int dma_chan;
        struct sata_dwc_device *hsdev = HSDEV_FROM_AP(ap);
        struct sata_dwc_device_port *hsdevp = HSDEVP_FROM_AP(ap);

        dev_dbg(ap->dev, "%s: port=%d dma dir=%s n_elem=%d\n",
                __func__, ap->port_no, get_dma_dir_descript(qc->dma_dir),
                 qc->n_elem);

        dma_chan = dma_dwc_xfer_setup(sg, qc->n_elem, hsdevp->llit[tag],
                                      hsdevp->llit_dma[tag],
                                      (void *__iomem)(&hsdev->sata_dwc_regs->\
                                      dmadr), qc->dma_dir);
        if (dma_chan < 0) {
                dev_err(ap->dev, "%s: dma_dwc_xfer_setup returns err %d\n",
                        __func__, dma_chan);
                return;
        }
        hsdevp->dma_chan[tag] = dma_chan;
}

static unsigned int sata_dwc_qc_issue(struct ata_queued_cmd *qc)
{
        u32 sactive;
        u8 tag = qc->tag;
        struct ata_port *ap = qc->ap;

#ifdef DEBUG_NCQ
        if (qc->tag > 0 || ap->link.sactive > 1)
                dev_info(ap->dev, "%s ap id=%d cmd(0x%02x)=%s qc tag=%d "
                         "prot=%s ap active_tag=0x%08x ap sactive=0x%08x\n",
                         __func__, ap->print_id, qc->tf.command,
                         ata_get_cmd_descript(qc->tf.command),
                         qc->tag, get_prot_descript(qc->tf.protocol),
                         ap->link.active_tag, ap->link.sactive);
#endif

        if (!ata_is_ncq(qc->tf.protocol))
                tag = 0;
        sata_dwc_qc_prep_by_tag(qc, tag);

        if (ata_is_ncq(qc->tf.protocol)) {
                sactive = core_scr_read(SCR_ACTIVE);
                sactive |= (0x00000001 << tag);
                core_scr_write(SCR_ACTIVE, sactive);

                dev_dbg(qc->ap->dev, "%s: tag=%d ap->link.sactive = 0x%08x "
                        "sactive=0x%08x\n", __func__, tag, qc->ap->link.sactive,
                        sactive);

                ap->ops->sff_tf_load(ap, &qc->tf);
                sata_dwc_exec_command_by_tag(ap, &qc->tf, qc->tag,
                                             SATA_DWC_CMD_ISSUED_PEND);
        } else {
                ata_sff_qc_issue(qc);
        }
        return 0;
}

/*
 * Function : sata_dwc_qc_prep
 * arguments : ata_queued_cmd *qc
 * Return value : None
 * qc_prep for a particular queued command
 */

static void sata_dwc_qc_prep(struct ata_queued_cmd *qc)
{
        if ((qc->dma_dir == DMA_NONE) || (qc->tf.protocol == ATA_PROT_PIO))
                return;

#ifdef DEBUG_NCQ
        if (qc->tag > 0)
                dev_info(qc->ap->dev, "%s: qc->tag=%d ap->active_tag=0x%08x\n",
                         __func__, qc->tag, qc->ap->link.active_tag);

        return ;
#endif
}

static void sata_dwc_error_handler(struct ata_port *ap)
{
        ata_sff_error_handler(ap);
}

int sata_dwc_hardreset(struct ata_link *link, unsigned int *class,
                        unsigned long deadline)
{
        struct sata_dwc_device *hsdev = HSDEV_FROM_AP(link->ap);
        int ret;

        ret = sata_sff_hardreset(link, class, deadline);

        sata_dwc_enable_interrupts(hsdev);

        /* Reconfigure the DMA control register */
        out_le32(&hsdev->sata_dwc_regs->dmacr,
                 SATA_DWC_DMACR_TXRXCH_CLEAR);

        /* Reconfigure the DMA Burst Transaction Size register */
        out_le32(&hsdev->sata_dwc_regs->dbtsr,
                 SATA_DWC_DBTSR_MWR(AHB_DMA_BRST_DFLT) |
                 SATA_DWC_DBTSR_MRD(AHB_DMA_BRST_DFLT));

        return ret;
}

/*
 * scsi mid-layer and libata interface structures
 */
static struct scsi_host_template sata_dwc_sht = {
        ATA_NCQ_SHT(DRV_NAME),
        /*
         * test-only: Currently this driver doesn't handle NCQ
         * correctly. We enable NCQ but set the queue depth to a
         * max of 1. This will get fixed in in a future release.
         */
        .sg_tablesize           = LIBATA_MAX_PRD,
        .can_queue              = ATA_DEF_QUEUE,        /* ATA_MAX_QUEUE */
        .dma_boundary           = ATA_DMA_BOUNDARY,
};

static struct ata_port_operations sata_dwc_ops = {
        .inherits               = &ata_sff_port_ops,

        .error_handler          = sata_dwc_error_handler,
        .hardreset              = sata_dwc_hardreset,

        .qc_prep                = sata_dwc_qc_prep,
        .qc_issue               = sata_dwc_qc_issue,

        .scr_read               = sata_dwc_scr_read,
        .scr_write              = sata_dwc_scr_write,

        .port_start             = sata_dwc_port_start,
        .port_stop              = sata_dwc_port_stop,

        .bmdma_setup            = sata_dwc_bmdma_setup,
        .bmdma_start            = sata_dwc_bmdma_start,
};

static const struct ata_port_info sata_dwc_port_info[] = {
        {
                .flags          = ATA_FLAG_SATA | ATA_FLAG_NCQ,
                .pio_mask       = ATA_PIO4,
                .udma_mask      = ATA_UDMA6,
                .port_ops       = &sata_dwc_ops,
        },
};

static int sata_dwc_probe(struct platform_device *ofdev)
{
        struct sata_dwc_device *hsdev;
        u32 idr, versionr;
        char *ver = (char *)&versionr;
        u8 *base = NULL;
        int err = 0;
        int irq, rc;
        struct ata_host *host;
        struct ata_port_info pi = sata_dwc_port_info[0];
        const struct ata_port_info *ppi[] = { &pi, NULL };
        struct device_node *np = ofdev->dev.of_node;
        u32 dma_chan;

        /* Allocate DWC SATA device */
        hsdev = kzalloc(sizeof(*hsdev), GFP_KERNEL);
        if (hsdev == NULL) {
                dev_err(&ofdev->dev, "kmalloc failed for hsdev\n");
                err = -ENOMEM;
                goto error;
        }

        if (of_property_read_u32(np, "dma-channel", &dma_chan)) {
                dev_warn(&ofdev->dev, "no dma-channel property set."
                         " Use channel 0\n");
                dma_chan = 0;
        }
        host_pvt.dma_channel = dma_chan;

        /* Ioremap SATA registers */
        base = of_iomap(ofdev->dev.of_node, 0);
        if (!base) {
                dev_err(&ofdev->dev, "ioremap failed for SATA register"
                        " address\n");
                err = -ENODEV;
                goto error_kmalloc;
        }
        hsdev->reg_base = base;
        dev_dbg(&ofdev->dev, "ioremap done for SATA register address\n");

        /* Synopsys DWC SATA specific Registers */
        hsdev->sata_dwc_regs = (void *__iomem)(base + SATA_DWC_REG_OFFSET);

        /* Allocate and fill host */
        host = ata_host_alloc_pinfo(&ofdev->dev, ppi, SATA_DWC_MAX_PORTS);
        if (!host) {
                dev_err(&ofdev->dev, "ata_host_alloc_pinfo failed\n");
                err = -ENOMEM;
                goto error_iomap;
        }

        host->private_data = hsdev;

        /* Setup port */
        host->ports[0]->ioaddr.cmd_addr = base;
        host->ports[0]->ioaddr.scr_addr = base + SATA_DWC_SCR_OFFSET;
        host_pvt.scr_addr_sstatus = base + SATA_DWC_SCR_OFFSET;
        sata_dwc_setup_port(&host->ports[0]->ioaddr, (unsigned long)base);

        /* Read the ID and Version Registers */
        idr = in_le32(&hsdev->sata_dwc_regs->idr);
        versionr = in_le32(&hsdev->sata_dwc_regs->versionr);
        dev_notice(&ofdev->dev, "id %d, controller version %c.%c%c\n",
                   idr, ver[0], ver[1], ver[2]);

        /* Get SATA DMA interrupt number */
        irq = irq_of_parse_and_map(ofdev->dev.of_node, 1);
        if (irq == NO_IRQ) {
                dev_err(&ofdev->dev, "no SATA DMA irq\n");
                err = -ENODEV;
                goto error_out;
        }

        /* Get physical SATA DMA register base address */
        host_pvt.sata_dma_regs = of_iomap(ofdev->dev.of_node, 1);
        if (!(host_pvt.sata_dma_regs)) {
                dev_err(&ofdev->dev, "ioremap failed for AHBDMA register"
                        " address\n");
                err = -ENODEV;
                goto error_out;
        }

        /* Save dev for later use in dev_xxx() routines */
        host_pvt.dwc_dev = &ofdev->dev;

        /* Initialize AHB DMAC */
        dma_dwc_init(hsdev, irq);

        /* Enable SATA Interrupts */
        sata_dwc_enable_interrupts(hsdev);

        /* Get SATA interrupt number */
        irq = irq_of_parse_and_map(ofdev->dev.of_node, 0);
        if (irq == NO_IRQ) {
                dev_err(&ofdev->dev, "no SATA DMA irq\n");
                err = -ENODEV;
                goto error_out;
        }

        /*
         * Now, register with libATA core, this will also initiate the
         * device discovery process, invoking our port_start() handler &
         * error_handler() to execute a dummy Softreset EH session
         */
        rc = ata_host_activate(host, irq, sata_dwc_isr, 0, &sata_dwc_sht);

        if (rc != 0)
                dev_err(&ofdev->dev, "failed to activate host");

        dev_set_drvdata(&ofdev->dev, host);
        return 0;

error_out:
        /* Free SATA DMA resources */
        dma_dwc_exit(hsdev);

error_iomap:
        iounmap(base);
error_kmalloc:
        kfree(hsdev);
error:
        return err;
}

static int sata_dwc_remove(struct platform_device *ofdev)
{
        struct device *dev = &ofdev->dev;
        struct ata_host *host = dev_get_drvdata(dev);
        struct sata_dwc_device *hsdev = host->private_data;

        ata_host_detach(host);
        dev_set_drvdata(dev, NULL);

        /* Free SATA DMA resources */
        dma_dwc_exit(hsdev);

        iounmap(hsdev->reg_base);
        kfree(hsdev);
        kfree(host);
        dev_dbg(&ofdev->dev, "done\n");
        return 0;
}

static const struct of_device_id sata_dwc_match[] = {
        { .compatible = "amcc,sata-460ex", },
        {}
};
MODULE_DEVICE_TABLE(of, sata_dwc_match);

static struct platform_driver sata_dwc_driver = {
        .driver = {
                .name = DRV_NAME,
                .owner = THIS_MODULE,
                .of_match_table = sata_dwc_match,
        },
        .probe = sata_dwc_probe,
        .remove = sata_dwc_remove,
};

module_platform_driver(sata_dwc_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mark Miesfeld <mmiesfeld@amcc.com>");
MODULE_DESCRIPTION("DesignWare Cores SATA controller low lever driver");
MODULE_VERSION(DRV_VERSION);