/*
 *  ahci.c - AHCI SATA support
 *
 *  Copyright 2004 Red Hat, Inc.
 *
 *  The contents of this file are subject to the Open
 *  Software License version 1.1 that can be found at
 *  http://www.opensource.org/licenses/osl-1.1.txt and is included herein
 *  by reference.
 *
 *  Alternatively, the contents of this file may be used under the terms
 *  of the GNU General Public License version 2 (the "GPL") as distributed
 *  in the kernel source COPYING file, in which case the provisions of
 *  the GPL are applicable instead of the above.  If you wish to allow
 *  the use of your version of this file only under the terms of the
 *  GPL and not to allow others to use your version of this file under
 *  the OSL, indicate your decision by deleting the provisions above and
 *  replace them with the notice and other provisions required by the GPL.
 *  If you do not delete the provisions above, a recipient may use your
 *  version of this file under either the OSL or the GPL.
 *
 * Version 1.0 of the AHCI specification:
 * http://www.intel.com/technology/serialata/pdf/rev1_0.pdf
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include "scsi.h"
#include <scsi/scsi_host.h>
#include <linux/libata.h>
#include <asm/io.h>

#define DRV_NAME        "ahci"
#define DRV_VERSION     "1.00"

enum {
        AHCI_PCI_BAR            = 5,
        AHCI_MAX_SG             = 168, /* hardware max is 64K */
        AHCI_DMA_BOUNDARY       = 0xffffffff,
        AHCI_USE_CLUSTERING     = 0,
        AHCI_CMD_SLOT_SZ        = 32 * 32,
        AHCI_RX_FIS_SZ          = 256,
        AHCI_CMD_TBL_HDR        = 0x80,
        AHCI_CMD_TBL_SZ         = AHCI_CMD_TBL_HDR + (AHCI_MAX_SG * 16),
        AHCI_PORT_PRIV_DMA_SZ   = AHCI_CMD_SLOT_SZ + AHCI_CMD_TBL_SZ +
                                  AHCI_RX_FIS_SZ,
        AHCI_IRQ_ON_SG          = (1 << 31),
        AHCI_CMD_ATAPI          = (1 << 5),
        AHCI_CMD_WRITE          = (1 << 6),

        RX_FIS_D2H_REG          = 0x40, /* offset of D2H Register FIS data */

        board_ahci              = 0,

        /* global controller registers */
        HOST_CAP                = 0x00, /* host capabilities */
        HOST_CTL                = 0x04, /* global host control */
        HOST_IRQ_STAT           = 0x08, /* interrupt status */
        HOST_PORTS_IMPL         = 0x0c, /* bitmap of implemented ports */
        HOST_VERSION            = 0x10, /* AHCI spec. version compliancy */

        /* HOST_CTL bits */
        HOST_RESET              = (1 << 0),  /* reset controller; self-clear */
        HOST_IRQ_EN             = (1 << 1),  /* global IRQ enable */
        HOST_AHCI_EN            = (1 << 31), /* AHCI enabled */

        /* HOST_CAP bits */
        HOST_CAP_64             = (1 << 31), /* PCI DAC (64-bit DMA) support */

        /* registers for each SATA port */
        PORT_LST_ADDR           = 0x00, /* command list DMA addr */
        PORT_LST_ADDR_HI        = 0x04, /* command list DMA addr hi */
        PORT_FIS_ADDR           = 0x08, /* FIS rx buf addr */
        PORT_FIS_ADDR_HI        = 0x0c, /* FIS rx buf addr hi */
        PORT_IRQ_STAT           = 0x10, /* interrupt status */
        PORT_IRQ_MASK           = 0x14, /* interrupt enable/disable mask */
        PORT_CMD                = 0x18, /* port command */
        PORT_TFDATA             = 0x20, /* taskfile data */
        PORT_SIG                = 0x24, /* device TF signature */
        PORT_CMD_ISSUE          = 0x38, /* command issue */
        PORT_SCR                = 0x28, /* SATA phy register block */
        PORT_SCR_STAT           = 0x28, /* SATA phy register: SStatus */
        PORT_SCR_CTL            = 0x2c, /* SATA phy register: SControl */
        PORT_SCR_ERR            = 0x30, /* SATA phy register: SError */
        PORT_SCR_ACT            = 0x34, /* SATA phy register: SActive */

        /* PORT_IRQ_{STAT,MASK} bits */
        PORT_IRQ_COLD_PRES      = (1 << 31), /* cold presence detect */
        PORT_IRQ_TF_ERR         = (1 << 30), /* task file error */
        PORT_IRQ_HBUS_ERR       = (1 << 29), /* host bus fatal error */
        PORT_IRQ_HBUS_DATA_ERR  = (1 << 28), /* host bus data error */
        PORT_IRQ_IF_ERR         = (1 << 27), /* interface fatal error */
        PORT_IRQ_IF_NONFATAL    = (1 << 26), /* interface non-fatal error */
        PORT_IRQ_OVERFLOW       = (1 << 24), /* xfer exhausted available S/G */
        PORT_IRQ_BAD_PMP        = (1 << 23), /* incorrect port multiplier */

        PORT_IRQ_PHYRDY         = (1 << 22), /* PhyRdy changed */
        PORT_IRQ_DEV_ILCK       = (1 << 7), /* device interlock */
        PORT_IRQ_CONNECT        = (1 << 6), /* port connect change status */
        PORT_IRQ_SG_DONE        = (1 << 5), /* descriptor processed */
        PORT_IRQ_UNK_FIS        = (1 << 4), /* unknown FIS rx'd */
        PORT_IRQ_SDB_FIS        = (1 << 3), /* Set Device Bits FIS rx'd */
        PORT_IRQ_DMAS_FIS       = (1 << 2), /* DMA Setup FIS rx'd */
        PORT_IRQ_PIOS_FIS       = (1 << 1), /* PIO Setup FIS rx'd */
        PORT_IRQ_D2H_REG_FIS    = (1 << 0), /* D2H Register FIS rx'd */

        PORT_IRQ_FATAL          = PORT_IRQ_TF_ERR |
                                  PORT_IRQ_HBUS_ERR |
                                  PORT_IRQ_HBUS_DATA_ERR |
                                  PORT_IRQ_IF_ERR,
        DEF_PORT_IRQ            = PORT_IRQ_FATAL | PORT_IRQ_PHYRDY |
                                  PORT_IRQ_CONNECT | PORT_IRQ_SG_DONE |
                                  PORT_IRQ_UNK_FIS | PORT_IRQ_SDB_FIS |
                                  PORT_IRQ_DMAS_FIS | PORT_IRQ_PIOS_FIS |
                                  PORT_IRQ_D2H_REG_FIS,

        /* PORT_CMD bits */
        PORT_CMD_LIST_ON        = (1 << 15), /* cmd list DMA engine running */
        PORT_CMD_FIS_ON         = (1 << 14), /* FIS DMA engine running */
        PORT_CMD_FIS_RX         = (1 << 4), /* Enable FIS receive DMA engine */
        PORT_CMD_POWER_ON       = (1 << 2), /* Power up device */
        PORT_CMD_SPIN_UP        = (1 << 1), /* Spin up device */
        PORT_CMD_START          = (1 << 0), /* Enable port DMA engine */

        PORT_CMD_ICC_ACTIVE     = (0x1 << 28), /* Put i/f in active state */
        PORT_CMD_ICC_PARTIAL    = (0x2 << 28), /* Put i/f in partial state */
        PORT_CMD_ICC_SLUMBER    = (0x6 << 28), /* Put i/f in slumber state */
};

struct ahci_cmd_hdr {
        u32                     opts;
        u32                     status;
        u32                     tbl_addr;
        u32                     tbl_addr_hi;
        u32                     reserved[4];
};

struct ahci_sg {
        u32                     addr;
        u32                     addr_hi;
        u32                     reserved;
        u32                     flags_size;
};

struct ahci_host_priv {
        unsigned long           flags;
        u32                     cap;    /* cache of HOST_CAP register */
        u32                     port_map; /* cache of HOST_PORTS_IMPL reg */
};

struct ahci_port_priv {
        struct ahci_cmd_hdr     *cmd_slot;
        dma_addr_t              cmd_slot_dma;
        void                    *cmd_tbl;
        dma_addr_t              cmd_tbl_dma;
        struct ahci_sg          *cmd_tbl_sg;
        void                    *rx_fis;
        dma_addr_t              rx_fis_dma;
};

static u32 ahci_scr_read (struct ata_port *ap, unsigned int sc_reg);
static void ahci_scr_write (struct ata_port *ap, unsigned int sc_reg, u32 val);
static int ahci_init_one (struct pci_dev *pdev, const struct pci_device_id *ent);
static int ahci_qc_issue(struct ata_queued_cmd *qc);
static irqreturn_t ahci_interrupt (int irq, void *dev_instance, struct pt_regs *regs);
static void ahci_phy_reset(struct ata_port *ap);
static void ahci_irq_clear(struct ata_port *ap);
static void ahci_eng_timeout(struct ata_port *ap);
static int ahci_port_start(struct ata_port *ap);
static void ahci_port_stop(struct ata_port *ap);
static void ahci_host_stop(struct ata_host_set *host_set);
static void ahci_tf_read(struct ata_port *ap, struct ata_taskfile *tf);
static void ahci_qc_prep(struct ata_queued_cmd *qc);
static u8 ahci_check_status(struct ata_port *ap);
static u8 ahci_check_err(struct ata_port *ap);
static inline int ahci_host_intr(struct ata_port *ap, struct ata_queued_cmd *qc);

static Scsi_Host_Template ahci_sht = {
        .module                 = THIS_MODULE,
        .name                   = DRV_NAME,
        .ioctl                  = ata_scsi_ioctl,
        .detect                 = ata_scsi_detect,
        .release                = ata_scsi_release,
        .queuecommand           = ata_scsi_queuecmd,
        .eh_strategy_handler    = ata_scsi_error,
        .can_queue              = ATA_DEF_QUEUE,
        .this_id                = ATA_SHT_THIS_ID,
        .sg_tablesize           = AHCI_MAX_SG,
        .max_sectors            = ATA_MAX_SECTORS,
        .cmd_per_lun            = ATA_SHT_CMD_PER_LUN,
        .use_new_eh_code        = ATA_SHT_NEW_EH_CODE,
        .emulated               = ATA_SHT_EMULATED,
        .use_clustering         = AHCI_USE_CLUSTERING,
        .proc_name              = DRV_NAME,
        .bios_param             = ata_std_bios_param,
};

static struct ata_port_operations ahci_ops = {
        .port_disable           = ata_port_disable,

        .check_status           = ahci_check_status,
        .check_altstatus        = ahci_check_status,
        .check_err              = ahci_check_err,
        .dev_select             = ata_noop_dev_select,

        .tf_read                = ahci_tf_read,

        .phy_reset              = ahci_phy_reset,

        .qc_prep                = ahci_qc_prep,
        .qc_issue               = ahci_qc_issue,

        .eng_timeout            = ahci_eng_timeout,

        .irq_handler            = ahci_interrupt,
        .irq_clear              = ahci_irq_clear,

        .scr_read               = ahci_scr_read,
        .scr_write              = ahci_scr_write,

        .port_start             = ahci_port_start,
        .port_stop              = ahci_port_stop,
        .host_stop              = ahci_host_stop,
};

static struct ata_port_info ahci_port_info[] = {
        /* board_ahci */
        {
                .sht            = &ahci_sht,
                .host_flags     = ATA_FLAG_SATA | ATA_FLAG_NO_LEGACY |
                                  ATA_FLAG_SATA_RESET | ATA_FLAG_MMIO |
                                  ATA_FLAG_PIO_DMA,
                .pio_mask       = 0x03, /* pio3-4 */
                .udma_mask      = 0x7f, /* udma0-6 ; FIXME */
                .port_ops       = &ahci_ops,
        },
};

static struct pci_device_id ahci_pci_tbl[] = {
        { PCI_VENDOR_ID_INTEL, 0x2652, PCI_ANY_ID, PCI_ANY_ID, 0, 0,
          board_ahci }, /* ICH6 */
        { PCI_VENDOR_ID_INTEL, 0x2653, PCI_ANY_ID, PCI_ANY_ID, 0, 0,
          board_ahci }, /* ICH6M */
        { PCI_VENDOR_ID_INTEL, 0x27c1, PCI_ANY_ID, PCI_ANY_ID, 0, 0,
          board_ahci }, /* ICH7 */
        { PCI_VENDOR_ID_INTEL, 0x27c5, PCI_ANY_ID, PCI_ANY_ID, 0, 0,
          board_ahci }, /* ICH7M */
        { PCI_VENDOR_ID_INTEL, 0x27c3, PCI_ANY_ID, PCI_ANY_ID, 0, 0,
          board_ahci }, /* ICH7R */
        { PCI_VENDOR_ID_AL, 0x5288, PCI_ANY_ID, PCI_ANY_ID, 0, 0,
          board_ahci }, /* ULi M5288 */
        { }     /* terminate list */
};


static struct pci_driver ahci_pci_driver = {
        .name                   = DRV_NAME,
        .id_table               = ahci_pci_tbl,
        .probe                  = ahci_init_one,
        .remove                 = ata_pci_remove_one,
};


static inline unsigned long ahci_port_base_ul (unsigned long base, unsigned int port)
{
        return base + 0x100 + (port * 0x80);
}

static inline void *ahci_port_base (void *base, unsigned int port)
{
        return (void *) ahci_port_base_ul((unsigned long)base, port);
}

static void ahci_host_stop(struct ata_host_set *host_set)
{
        struct ahci_host_priv *hpriv = host_set->private_data;
        kfree(hpriv);
}

static int ahci_port_start(struct ata_port *ap)
{
        struct device *dev = ap->host_set->dev;
        struct ahci_host_priv *hpriv = ap->host_set->private_data;
        struct ahci_port_priv *pp;
        int rc;
        void *mem, *mmio = ap->host_set->mmio_base;
        void *port_mmio = ahci_port_base(mmio, ap->port_no);
        dma_addr_t mem_dma;

        rc = ata_port_start(ap);
        if (rc)
                return rc;

        pp = kmalloc(sizeof(*pp), GFP_KERNEL);
        if (!pp) {
                rc = -ENOMEM;
                goto err_out;
        }
        memset(pp, 0, sizeof(*pp));

        mem = dma_alloc_coherent(dev, AHCI_PORT_PRIV_DMA_SZ, &mem_dma, GFP_KERNEL);
        if (!mem) {
                rc = -ENOMEM;
                goto err_out_kfree;
        }
        memset(mem, 0, AHCI_PORT_PRIV_DMA_SZ);

        /*
         * First item in chunk of DMA memory: 32-slot command table,
         * 32 bytes each in size
         */
        pp->cmd_slot = mem;
        pp->cmd_slot_dma = mem_dma;

        mem += AHCI_CMD_SLOT_SZ;
        mem_dma += AHCI_CMD_SLOT_SZ;

        /*
         * Second item: Received-FIS area
         */
        pp->rx_fis = mem;
        pp->rx_fis_dma = mem_dma;

        mem += AHCI_RX_FIS_SZ;
        mem_dma += AHCI_RX_FIS_SZ;

        /*
         * Third item: data area for storing a single command
         * and its scatter-gather table
         */
        pp->cmd_tbl = mem;
        pp->cmd_tbl_dma = mem_dma;

        pp->cmd_tbl_sg = mem + AHCI_CMD_TBL_HDR;

        ap->private_data = pp;

        if (hpriv->cap & HOST_CAP_64)
                writel((pp->cmd_slot_dma >> 16) >> 16, port_mmio + PORT_LST_ADDR_HI);
        writel(pp->cmd_slot_dma & 0xffffffff, port_mmio + PORT_LST_ADDR);
        readl(port_mmio + PORT_LST_ADDR); /* flush */

        if (hpriv->cap & HOST_CAP_64)
                writel((pp->rx_fis_dma >> 16) >> 16, port_mmio + PORT_FIS_ADDR_HI);
        writel(pp->rx_fis_dma & 0xffffffff, port_mmio + PORT_FIS_ADDR);
        readl(port_mmio + PORT_FIS_ADDR); /* flush */

        writel(PORT_CMD_ICC_ACTIVE | PORT_CMD_FIS_RX |
               PORT_CMD_POWER_ON | PORT_CMD_SPIN_UP |
               PORT_CMD_START, port_mmio + PORT_CMD);
        readl(port_mmio + PORT_CMD); /* flush */

        return 0;

err_out_kfree:
        kfree(pp);
err_out:
        ata_port_stop(ap);
        return rc;
}


static void ahci_port_stop(struct ata_port *ap)
{
        struct device *dev = ap->host_set->dev;
        struct ahci_port_priv *pp = ap->private_data;
        void *mmio = ap->host_set->mmio_base;
        void *port_mmio = ahci_port_base(mmio, ap->port_no);
        u32 tmp;

        tmp = readl(port_mmio + PORT_CMD);
        tmp &= ~(PORT_CMD_START | PORT_CMD_FIS_RX);
        writel(tmp, port_mmio + PORT_CMD);
        readl(port_mmio + PORT_CMD); /* flush */

        /* spec says 500 msecs for each PORT_CMD_{START,FIS_RX} bit, so
         * this is slightly incorrect.
         */
        msleep(500);

        ap->private_data = NULL;
        dma_free_coherent(dev, AHCI_PORT_PRIV_DMA_SZ,
                          pp->cmd_slot, pp->cmd_slot_dma);
        kfree(pp);
        ata_port_stop(ap);
}

static u32 ahci_scr_read (struct ata_port *ap, unsigned int sc_reg_in)
{
        unsigned int sc_reg;

        switch (sc_reg_in) {
        case SCR_STATUS:        sc_reg = 0; break;
        case SCR_CONTROL:       sc_reg = 1; break;
        case SCR_ERROR:         sc_reg = 2; break;
        case SCR_ACTIVE:        sc_reg = 3; break;
        default:
                return 0xffffffffU;
        }

        return readl((void *) ap->ioaddr.scr_addr + (sc_reg * 4));
}


static void ahci_scr_write (struct ata_port *ap, unsigned int sc_reg_in,
                               u32 val)
{
        unsigned int sc_reg;

        switch (sc_reg_in) {
        case SCR_STATUS:        sc_reg = 0; break;
        case SCR_CONTROL:       sc_reg = 1; break;
        case SCR_ERROR:         sc_reg = 2; break;
        case SCR_ACTIVE:        sc_reg = 3; break;
        default:
                return;
        }

        writel(val, (void *) ap->ioaddr.scr_addr + (sc_reg * 4));
}

static void ahci_phy_reset(struct ata_port *ap)
{
        void __iomem *port_mmio = (void __iomem *) ap->ioaddr.cmd_addr;
        struct ata_taskfile tf;
        struct ata_device *dev = &ap->device[0];
        u32 tmp;

        __sata_phy_reset(ap);

        if (ap->flags & ATA_FLAG_PORT_DISABLED)
                return;

        tmp = readl(port_mmio + PORT_SIG);
        tf.lbah         = (tmp >> 24)   & 0xff;
        tf.lbam         = (tmp >> 16)   & 0xff;
        tf.lbal         = (tmp >> 8)    & 0xff;
        tf.nsect        = (tmp)         & 0xff;

        dev->class = ata_dev_classify(&tf);
        if (!ata_dev_present(dev))
                ata_port_disable(ap);
}

static u8 ahci_check_status(struct ata_port *ap)
{
        void *mmio = (void *) ap->ioaddr.cmd_addr;

        return readl(mmio + PORT_TFDATA) & 0xFF;
}

static u8 ahci_check_err(struct ata_port *ap)
{
        void *mmio = (void *) ap->ioaddr.cmd_addr;

        return (readl(mmio + PORT_TFDATA) >> 8) & 0xFF;
}

static void ahci_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
{
        struct ahci_port_priv *pp = ap->private_data;
        u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;

        ata_tf_from_fis(d2h_fis, tf);
}

static void ahci_fill_sg(struct ata_queued_cmd *qc)
{
        struct ahci_port_priv *pp = qc->ap->private_data;
        unsigned int i;

        VPRINTK("ENTER\n");

        /*
         * Next, the S/G list.
         */
        for (i = 0; i < qc->n_elem; i++) {
                u32 sg_len;
                dma_addr_t addr;

                addr = sg_dma_address(&qc->sg[i]);
                sg_len = sg_dma_len(&qc->sg[i]);

                pp->cmd_tbl_sg[i].addr = cpu_to_le32(addr & 0xffffffff);
                pp->cmd_tbl_sg[i].addr_hi = cpu_to_le32((addr >> 16) >> 16);
                pp->cmd_tbl_sg[i].flags_size = cpu_to_le32(sg_len - 1);
        }
}

static void ahci_qc_prep(struct ata_queued_cmd *qc)
{
        struct ahci_port_priv *pp = qc->ap->private_data;
        u32 opts;
        const u32 cmd_fis_len = 5; /* five dwords */

        /*
         * Fill in command slot information (currently only one slot,
         * slot 0, is currently since we don't do queueing)
         */

        opts = (qc->n_elem << 16) | cmd_fis_len;
        if (qc->tf.flags & ATA_TFLAG_WRITE)
                opts |= AHCI_CMD_WRITE;

        switch (qc->tf.protocol) {
        case ATA_PROT_ATAPI:
        case ATA_PROT_ATAPI_NODATA:
        case ATA_PROT_ATAPI_DMA:
                opts |= AHCI_CMD_ATAPI;
                break;

        default:
                /* do nothing */
                break;
        }

        pp->cmd_slot[0].opts = cpu_to_le32(opts);
        pp->cmd_slot[0].status = 0;
        pp->cmd_slot[0].tbl_addr = cpu_to_le32(pp->cmd_tbl_dma & 0xffffffff);
        pp->cmd_slot[0].tbl_addr_hi = cpu_to_le32((pp->cmd_tbl_dma >> 16) >> 16);

        /*
         * Fill in command table information.  First, the header,
         * a SATA Register - Host to Device command FIS.
         */
        ata_tf_to_fis(&qc->tf, pp->cmd_tbl, 0);

        if (!(qc->flags & ATA_QCFLAG_DMAMAP))
                return;

        ahci_fill_sg(qc);
}

static void ahci_intr_error(struct ata_port *ap, u32 irq_stat)
{
        void *mmio = ap->host_set->mmio_base;
        void *port_mmio = ahci_port_base(mmio, ap->port_no);
        u32 tmp;
        int work;

        /* stop DMA */
        tmp = readl(port_mmio + PORT_CMD);
        tmp &= ~PORT_CMD_START;
        writel(tmp, port_mmio + PORT_CMD);

        /* wait for engine to stop.  TODO: this could be
         * as long as 500 msec
         */
        work = 1000;
        while (work-- > 0) {
                tmp = readl(port_mmio + PORT_CMD);
                if ((tmp & PORT_CMD_LIST_ON) == 0)
                        break;
                udelay(10);
        }

        /* clear SATA phy error, if any */
        tmp = readl(port_mmio + PORT_SCR_ERR);
        writel(tmp, port_mmio + PORT_SCR_ERR);

        /* if DRQ/BSY is set, device needs to be reset.
         * if so, issue COMRESET
         */
        tmp = readl(port_mmio + PORT_TFDATA);
        if (tmp & (ATA_BUSY | ATA_DRQ)) {
                writel(0x301, port_mmio + PORT_SCR_CTL);
                readl(port_mmio + PORT_SCR_CTL); /* flush */
                udelay(10);
                writel(0x300, port_mmio + PORT_SCR_CTL);
                readl(port_mmio + PORT_SCR_CTL); /* flush */
        }

        /* re-start DMA */
        tmp = readl(port_mmio + PORT_CMD);
        tmp |= PORT_CMD_START;
        writel(tmp, port_mmio + PORT_CMD);
        readl(port_mmio + PORT_CMD); /* flush */

        printk(KERN_WARNING "ata%u: error occurred, port reset\n", ap->id);
}

static void ahci_eng_timeout(struct ata_port *ap)
{
        void *mmio = ap->host_set->mmio_base;
        void *port_mmio = ahci_port_base(mmio, ap->port_no);
        struct ata_queued_cmd *qc;

        DPRINTK("ENTER\n");

        ahci_intr_error(ap, readl(port_mmio + PORT_IRQ_STAT));

        qc = ata_qc_from_tag(ap, ap->active_tag);
        if (!qc) {
                printk(KERN_ERR "ata%u: BUG: timeout without command\n",
                       ap->id);
        } else {
                /* hack alert!  We cannot use the supplied completion
                 * function from inside the ->eh_strategy_handler() thread.
                 * libata is the only user of ->eh_strategy_handler() in
                 * any kernel, so the default scsi_done() assumes it is
                 * not being called from the SCSI EH.
                 */
                qc->scsidone = scsi_finish_command;
                ata_qc_complete(qc, ATA_ERR);
        }

}

static inline int ahci_host_intr(struct ata_port *ap, struct ata_queued_cmd *qc)
{
        void *mmio = ap->host_set->mmio_base;
        void *port_mmio = ahci_port_base(mmio, ap->port_no);
        u32 status, serr, ci;

        serr = readl(port_mmio + PORT_SCR_ERR);
        writel(serr, port_mmio + PORT_SCR_ERR);

        status = readl(port_mmio + PORT_IRQ_STAT);
        writel(status, port_mmio + PORT_IRQ_STAT);

        ci = readl(port_mmio + PORT_CMD_ISSUE);
        if (likely((ci & 0x1) == 0)) {
                if (qc) {
                        ata_qc_complete(qc, 0);
                        qc = NULL;
                }
        }

        if (status & PORT_IRQ_FATAL) {
                ahci_intr_error(ap, status);
                if (qc)
                        ata_qc_complete(qc, ATA_ERR);
        }

        return 1;
}

static void ahci_irq_clear(struct ata_port *ap)
{
        /* TODO */
}

static irqreturn_t ahci_interrupt (int irq, void *dev_instance, struct pt_regs *regs)
{
        struct ata_host_set *host_set = dev_instance;
        struct ahci_host_priv *hpriv;
        unsigned int i, handled = 0;
        void *mmio;
        u32 irq_stat, irq_ack = 0;

        VPRINTK("ENTER\n");

        hpriv = host_set->private_data;
        mmio = host_set->mmio_base;

        /* sigh.  0xffffffff is a valid return from h/w */
        irq_stat = readl(mmio + HOST_IRQ_STAT);
        irq_stat &= hpriv->port_map;
        if (!irq_stat)
                return IRQ_NONE;

        spin_lock(&host_set->lock);

        for (i = 0; i < host_set->n_ports; i++) {
                struct ata_port *ap;
                u32 tmp;

                VPRINTK("port %u\n", i);
                ap = host_set->ports[i];
                tmp = irq_stat & (1 << i);
                if (tmp && ap) {
                        struct ata_queued_cmd *qc;
                        qc = ata_qc_from_tag(ap, ap->active_tag);
                        if (ahci_host_intr(ap, qc))
                                irq_ack |= (1 << i);
                }
        }

        if (irq_ack) {
                writel(irq_ack, mmio + HOST_IRQ_STAT);
                handled = 1;
        }

        spin_unlock(&host_set->lock);

        VPRINTK("EXIT\n");

        return IRQ_RETVAL(handled);
}

static int ahci_qc_issue(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        void *port_mmio = (void *) ap->ioaddr.cmd_addr;

        writel(1, port_mmio + PORT_SCR_ACT);
        readl(port_mmio + PORT_SCR_ACT);        /* flush */

        writel(1, port_mmio + PORT_CMD_ISSUE);
        readl(port_mmio + PORT_CMD_ISSUE);      /* flush */

        return 0;
}

static void ahci_setup_port(struct ata_ioports *port, unsigned long base,
                            unsigned int port_idx)
{
        VPRINTK("ENTER, base==0x%lx, port_idx %u\n", base, port_idx);
        base = ahci_port_base_ul(base, port_idx);
        VPRINTK("base now==0x%lx\n", base);

        port->cmd_addr          = base;
        port->scr_addr          = base + PORT_SCR;

        VPRINTK("EXIT\n");
}

static int ahci_host_init(struct ata_probe_ent *probe_ent)
{
        struct ahci_host_priv *hpriv = probe_ent->private_data;
        struct pci_dev *pdev = to_pci_dev(probe_ent->dev);
        void __iomem *mmio = probe_ent->mmio_base;
        u32 tmp, cap_save;
        u16 tmp16;
        unsigned int i, j, using_dac;
        int rc;
        void __iomem *port_mmio;

        cap_save = readl(mmio + HOST_CAP);
        cap_save &= ( (1<<28) | (1<<17) );
        cap_save |= (1 << 27);

        /* global controller reset */
        tmp = readl(mmio + HOST_CTL);
        if ((tmp & HOST_RESET) == 0) {
                writel(tmp | HOST_RESET, mmio + HOST_CTL);
                readl(mmio + HOST_CTL); /* flush */
        }

        /* reset must complete within 1 second, or
         * the hardware should be considered fried.
         */
        ssleep(1);

        tmp = readl(mmio + HOST_CTL);
        if (tmp & HOST_RESET) {
                printk(KERN_ERR DRV_NAME "(%s): controller reset failed (0x%x)\n",
                        pci_name(pdev), tmp);
                return -EIO;
        }

        writel(HOST_AHCI_EN, mmio + HOST_CTL);
        (void) readl(mmio + HOST_CTL);  /* flush */
        writel(cap_save, mmio + HOST_CAP);
        writel(0xf, mmio + HOST_PORTS_IMPL);
        (void) readl(mmio + HOST_PORTS_IMPL);   /* flush */

        pci_read_config_word(pdev, 0x92, &tmp16);
        tmp16 |= 0xf;
        pci_write_config_word(pdev, 0x92, tmp16);

        hpriv->cap = readl(mmio + HOST_CAP);
        hpriv->port_map = readl(mmio + HOST_PORTS_IMPL);
        probe_ent->n_ports = (hpriv->cap & 0x1f) + 1;

        VPRINTK("cap 0x%x  port_map 0x%x  n_ports %d\n",
                hpriv->cap, hpriv->port_map, probe_ent->n_ports);

        using_dac = hpriv->cap & HOST_CAP_64;
        if (using_dac &&
            !pci_set_dma_mask(pdev, DMA_64BIT_MASK)) {
                hpriv->flags |= HOST_CAP_64;
        } else {
                rc = pci_set_dma_mask(pdev, DMA_32BIT_MASK);
                if (rc) {
                        printk(KERN_ERR DRV_NAME "(%s): 32-bit DMA enable failed\n",
                                pci_name(pdev));
                        return rc;
                }
        }

        for (i = 0; i < probe_ent->n_ports; i++) {
#if 0 /* BIOSen initialize this incorrectly */
                if (!(hpriv->port_map & (1 << i)))
                        continue;
#endif

                port_mmio = ahci_port_base(mmio, i);
                VPRINTK("mmio %p  port_mmio %p\n", mmio, port_mmio);

                ahci_setup_port(&probe_ent->port[i],
                                (unsigned long) mmio, i);

                /* make sure port is not active */
                tmp = readl(port_mmio + PORT_CMD);
                VPRINTK("PORT_CMD 0x%x\n", tmp);
                if (tmp & (PORT_CMD_LIST_ON | PORT_CMD_FIS_ON |
                           PORT_CMD_FIS_RX | PORT_CMD_START)) {
                        tmp &= ~(PORT_CMD_LIST_ON | PORT_CMD_FIS_ON |
                                 PORT_CMD_FIS_RX | PORT_CMD_START);
                        writel(tmp, port_mmio + PORT_CMD);
                        readl(port_mmio + PORT_CMD); /* flush */

                        /* spec says 500 msecs for each bit, so
                         * this is slightly incorrect.
                         */
                        msleep(500);
                }

                writel(PORT_CMD_SPIN_UP, port_mmio + PORT_CMD);

                j = 0;
                while (j < 100) {
                        msleep(10);
                        tmp = readl(port_mmio + PORT_SCR_STAT);
                        if ((tmp & 0xf) == 0x3)
                                break;
                        j++;
                }

                tmp = readl(port_mmio + PORT_SCR_ERR);
                VPRINTK("PORT_SCR_ERR 0x%x\n", tmp);
                writel(tmp, port_mmio + PORT_SCR_ERR);

                /* ack any pending irq events for this port */
                tmp = readl(port_mmio + PORT_IRQ_STAT);
                VPRINTK("PORT_IRQ_STAT 0x%x\n", tmp);
                if (tmp)
                        writel(tmp, port_mmio + PORT_IRQ_STAT);

                writel(1 << i, mmio + HOST_IRQ_STAT);

                /* set irq mask (enables interrupts) */
                writel(DEF_PORT_IRQ, port_mmio + PORT_IRQ_MASK);
        }

        tmp = readl(mmio + HOST_CTL);
        VPRINTK("HOST_CTL 0x%x\n", tmp);
        writel(tmp | HOST_IRQ_EN, mmio + HOST_CTL);
        tmp = readl(mmio + HOST_CTL);
        VPRINTK("HOST_CTL 0x%x\n", tmp);

        pci_set_master(pdev);

        return 0;
}

/* move to PCI layer, integrate w/ MSI stuff */
static void pci_enable_intx(struct pci_dev *pdev)
{
        u16 pci_command;

        pci_read_config_word(pdev, PCI_COMMAND, &pci_command);
        if (pci_command & PCI_COMMAND_INTX_DISABLE) {
                pci_command &= ~PCI_COMMAND_INTX_DISABLE;
                pci_write_config_word(pdev, PCI_COMMAND, pci_command);
        }
}

static void ahci_print_info(struct ata_probe_ent *probe_ent)
{
        struct ahci_host_priv *hpriv = probe_ent->private_data;
        struct pci_dev *pdev = to_pci_dev(probe_ent->dev);
        void *mmio = probe_ent->mmio_base;
        u32 vers, cap, impl, speed;
        const char *speed_s;
        u16 cc;
        const char *scc_s;

        vers = readl(mmio + HOST_VERSION);
        cap = hpriv->cap;
        impl = hpriv->port_map;

        speed = (cap >> 20) & 0xf;
        if (speed == 1)
                speed_s = "1.5";
        else if (speed == 2)
                speed_s = "3";
        else
                speed_s = "?";

        pci_read_config_word(pdev, 0x0a, &cc);
        if (cc == 0x0101)
                scc_s = "IDE";
        else if (cc == 0x0106)
                scc_s = "SATA";
        else if (cc == 0x0104)
                scc_s = "RAID";
        else
                scc_s = "unknown";

        printk(KERN_INFO DRV_NAME "(%s) AHCI %02x%02x.%02x%02x "
                "%u slots %u ports %s Gbps 0x%x impl %s mode\n"
                ,
                pci_name(pdev),

                (vers >> 24) & 0xff,
                (vers >> 16) & 0xff,
                (vers >> 8) & 0xff,
                vers & 0xff,

                ((cap >> 8) & 0x1f) + 1,
                (cap & 0x1f) + 1,
                speed_s,
                impl,
                scc_s);

        printk(KERN_INFO DRV_NAME "(%s) flags: "
                "%s%s%s%s%s%s"
                "%s%s%s%s%s%s%s\n"
                ,
                pci_name(pdev),

                cap & (1 << 31) ? "64bit " : "",
                cap & (1 << 30) ? "ncq " : "",
                cap & (1 << 28) ? "ilck " : "",
                cap & (1 << 27) ? "stag " : "",
                cap & (1 << 26) ? "pm " : "",
                cap & (1 << 25) ? "led " : "",

                cap & (1 << 24) ? "clo " : "",
                cap & (1 << 19) ? "nz " : "",
                cap & (1 << 18) ? "only " : "",
                cap & (1 << 17) ? "pmp " : "",
                cap & (1 << 15) ? "pio " : "",
                cap & (1 << 14) ? "slum " : "",
                cap & (1 << 13) ? "part " : ""
                );
}

static int ahci_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
{
        static int printed_version;
        struct ata_probe_ent *probe_ent = NULL;
        struct ahci_host_priv *hpriv;
        unsigned long base;
        void *mmio_base;
        unsigned int board_idx = (unsigned int) ent->driver_data;
        int pci_dev_busy = 0;
        int rc;

        VPRINTK("ENTER\n");

        if (!printed_version++)
                printk(KERN_DEBUG DRV_NAME " version " DRV_VERSION "\n");

        rc = pci_enable_device(pdev);
        if (rc)
                return rc;

        rc = pci_request_regions(pdev, DRV_NAME);
        if (rc) {
                pci_dev_busy = 1;
                goto err_out;
        }

        pci_enable_intx(pdev);

        probe_ent = kmalloc(sizeof(*probe_ent), GFP_KERNEL);
        if (probe_ent == NULL) {
                rc = -ENOMEM;
                goto err_out_regions;
        }

        memset(probe_ent, 0, sizeof(*probe_ent));
        probe_ent->dev = pci_dev_to_dev(pdev);
        INIT_LIST_HEAD(&probe_ent->node);

        mmio_base = ioremap(pci_resource_start(pdev, AHCI_PCI_BAR),
                            pci_resource_len(pdev, AHCI_PCI_BAR));
        if (mmio_base == NULL) {
                rc = -ENOMEM;
                goto err_out_free_ent;
        }
        base = (unsigned long) mmio_base;

        hpriv = kmalloc(sizeof(*hpriv), GFP_KERNEL);
        if (!hpriv) {
                rc = -ENOMEM;
                goto err_out_iounmap;
        }
        memset(hpriv, 0, sizeof(*hpriv));

        probe_ent->sht          = ahci_port_info[board_idx].sht;
        probe_ent->host_flags   = ahci_port_info[board_idx].host_flags;
        probe_ent->pio_mask     = ahci_port_info[board_idx].pio_mask;
        probe_ent->udma_mask    = ahci_port_info[board_idx].udma_mask;
        probe_ent->port_ops     = ahci_port_info[board_idx].port_ops;

        probe_ent->irq = pdev->irq;
        probe_ent->irq_flags = SA_SHIRQ;
        probe_ent->mmio_base = mmio_base;
        probe_ent->private_data = hpriv;

        /* initialize adapter */
        rc = ahci_host_init(probe_ent);
        if (rc)
                goto err_out_hpriv;

        ahci_print_info(probe_ent);

        ata_add_to_probe_list(probe_ent);

        return 0;

err_out_hpriv:
        kfree(hpriv);
err_out_iounmap:
        iounmap(mmio_base);
err_out_free_ent:
        kfree(probe_ent);
err_out_regions:
        pci_release_regions(pdev);
err_out:
        if (!pci_dev_busy)
                pci_disable_device(pdev);
        return rc;
}


static int __init ahci_init(void)
{
        int rc;

        rc = pci_module_init(&ahci_pci_driver);
        if (rc)
                return rc;

        rc = scsi_register_module(MODULE_SCSI_HA, &ahci_sht);
        if (rc) {
                rc = -ENODEV;
                goto err_out;
        }

        return 0;

err_out:
        pci_unregister_driver(&ahci_pci_driver);
        return rc;
}


static void __exit ahci_exit(void)
{
        scsi_unregister_module(MODULE_SCSI_HA, &ahci_sht);
        pci_unregister_driver(&ahci_pci_driver);
}


MODULE_AUTHOR("Jeff Garzik");
MODULE_DESCRIPTION("AHCI SATA low-level driver");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pci, ahci_pci_tbl);

module_init(ahci_init);
module_exit(ahci_exit);