/*
 *  sata_qstor.c - Pacific Digital Corporation QStor SATA
 *
 *  Maintained by:  Mark Lord <mlord@pobox.com>
 *
 *  Copyright 2005 Pacific Digital Corporation.
 *  (OSL/GPL code release authorized by Jalil Fadavi).
 *
 *
 *  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, or (at your option)
 *  any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *
 *  libata documentation is available via 'make {ps|pdf}docs',
 *  as Documentation/driver-api/libata.rst
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/gfp.h>
#include <linux/pci.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <scsi/scsi_host.h>
#include <linux/libata.h>

#define DRV_NAME        "sata_qstor"
#define DRV_VERSION     "0.09"

enum {
        QS_MMIO_BAR             = 4,

        QS_PORTS                = 4,
        QS_MAX_PRD              = LIBATA_MAX_PRD,
        QS_CPB_ORDER            = 6,
        QS_CPB_BYTES            = (1 << QS_CPB_ORDER),
        QS_PRD_BYTES            = QS_MAX_PRD * 16,
        QS_PKT_BYTES            = QS_CPB_BYTES + QS_PRD_BYTES,

        /* global register offsets */
        QS_HCF_CNFG3            = 0x0003, /* host configuration offset */
        QS_HID_HPHY             = 0x0004, /* host physical interface info */
        QS_HCT_CTRL             = 0x00e4, /* global interrupt mask offset */
        QS_HST_SFF              = 0x0100, /* host status fifo offset */
        QS_HVS_SERD3            = 0x0393, /* PHY enable offset */

        /* global control bits */
        QS_HPHY_64BIT           = (1 << 1), /* 64-bit bus detected */
        QS_CNFG3_GSRST          = 0x01,     /* global chip reset */
        QS_SERD3_PHY_ENA        = 0xf0,     /* PHY detection ENAble*/

        /* per-channel register offsets */
        QS_CCF_CPBA             = 0x0710, /* chan CPB base address */
        QS_CCF_CSEP             = 0x0718, /* chan CPB separation factor */
        QS_CFC_HUFT             = 0x0800, /* host upstream fifo threshold */
        QS_CFC_HDFT             = 0x0804, /* host downstream fifo threshold */
        QS_CFC_DUFT             = 0x0808, /* dev upstream fifo threshold */
        QS_CFC_DDFT             = 0x080c, /* dev downstream fifo threshold */
        QS_CCT_CTR0             = 0x0900, /* chan control-0 offset */
        QS_CCT_CTR1             = 0x0901, /* chan control-1 offset */
        QS_CCT_CFF              = 0x0a00, /* chan command fifo offset */

        /* channel control bits */
        QS_CTR0_REG             = (1 << 1),   /* register mode (vs. pkt mode) */
        QS_CTR0_CLER            = (1 << 2),   /* clear channel errors */
        QS_CTR1_RDEV            = (1 << 1),   /* sata phy/comms reset */
        QS_CTR1_RCHN            = (1 << 4),   /* reset channel logic */
        QS_CCF_RUN_PKT          = 0x107,      /* RUN a new dma PKT */

        /* pkt sub-field headers */
        QS_HCB_HDR              = 0x01,   /* Host Control Block header */
        QS_DCB_HDR              = 0x02,   /* Device Control Block header */

        /* pkt HCB flag bits */
        QS_HF_DIRO              = (1 << 0),   /* data DIRection Out */
        QS_HF_DAT               = (1 << 3),   /* DATa pkt */
        QS_HF_IEN               = (1 << 4),   /* Interrupt ENable */
        QS_HF_VLD               = (1 << 5),   /* VaLiD pkt */

        /* pkt DCB flag bits */
        QS_DF_PORD              = (1 << 2),   /* Pio OR Dma */
        QS_DF_ELBA              = (1 << 3),   /* Extended LBA (lba48) */

        /* PCI device IDs */
        board_2068_idx          = 0,    /* QStor 4-port SATA/RAID */
};

enum {
        QS_DMA_BOUNDARY         = ~0UL
};

typedef enum { qs_state_mmio, qs_state_pkt } qs_state_t;

struct qs_port_priv {
        u8                      *pkt;
        dma_addr_t              pkt_dma;
        qs_state_t              state;
};

static int qs_scr_read(struct ata_link *link, unsigned int sc_reg, u32 *val);
static int qs_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val);
static int qs_ata_init_one(struct pci_dev *pdev, const struct pci_device_id *ent);
static int qs_port_start(struct ata_port *ap);
static void qs_host_stop(struct ata_host *host);
static void qs_qc_prep(struct ata_queued_cmd *qc);
static unsigned int qs_qc_issue(struct ata_queued_cmd *qc);
static int qs_check_atapi_dma(struct ata_queued_cmd *qc);
static void qs_freeze(struct ata_port *ap);
static void qs_thaw(struct ata_port *ap);
static int qs_prereset(struct ata_link *link, unsigned long deadline);
static void qs_error_handler(struct ata_port *ap);

static struct scsi_host_template qs_ata_sht = {
        ATA_BASE_SHT(DRV_NAME),
        .sg_tablesize           = QS_MAX_PRD,
        .dma_boundary           = QS_DMA_BOUNDARY,
};

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

        .check_atapi_dma        = qs_check_atapi_dma,
        .qc_prep                = qs_qc_prep,
        .qc_issue               = qs_qc_issue,

        .freeze                 = qs_freeze,
        .thaw                   = qs_thaw,
        .prereset               = qs_prereset,
        .softreset              = ATA_OP_NULL,
        .error_handler          = qs_error_handler,
        .lost_interrupt         = ATA_OP_NULL,

        .scr_read               = qs_scr_read,
        .scr_write              = qs_scr_write,

        .port_start             = qs_port_start,
        .host_stop              = qs_host_stop,
};

static const struct ata_port_info qs_port_info[] = {
        /* board_2068_idx */
        {
                .flags          = ATA_FLAG_SATA | ATA_FLAG_PIO_POLLING,
                .pio_mask       = ATA_PIO4_ONLY,
                .udma_mask      = ATA_UDMA6,
                .port_ops       = &qs_ata_ops,
        },
};

static const struct pci_device_id qs_ata_pci_tbl[] = {
        { PCI_VDEVICE(PDC, 0x2068), board_2068_idx },

        { }     /* terminate list */
};

static struct pci_driver qs_ata_pci_driver = {
        .name                   = DRV_NAME,
        .id_table               = qs_ata_pci_tbl,
        .probe                  = qs_ata_init_one,
        .remove                 = ata_pci_remove_one,
};

static void __iomem *qs_mmio_base(struct ata_host *host)
{
        return host->iomap[QS_MMIO_BAR];
}

static int qs_check_atapi_dma(struct ata_queued_cmd *qc)
{
        return 1;       /* ATAPI DMA not supported */
}

static inline void qs_enter_reg_mode(struct ata_port *ap)
{
        u8 __iomem *chan = qs_mmio_base(ap->host) + (ap->port_no * 0x4000);
        struct qs_port_priv *pp = ap->private_data;

        pp->state = qs_state_mmio;
        writeb(QS_CTR0_REG, chan + QS_CCT_CTR0);
        readb(chan + QS_CCT_CTR0);        /* flush */
}

static inline void qs_reset_channel_logic(struct ata_port *ap)
{
        u8 __iomem *chan = qs_mmio_base(ap->host) + (ap->port_no * 0x4000);

        writeb(QS_CTR1_RCHN, chan + QS_CCT_CTR1);
        readb(chan + QS_CCT_CTR0);        /* flush */
        qs_enter_reg_mode(ap);
}

static void qs_freeze(struct ata_port *ap)
{
        u8 __iomem *mmio_base = qs_mmio_base(ap->host);

        writeb(0, mmio_base + QS_HCT_CTRL); /* disable host interrupts */
        qs_enter_reg_mode(ap);
}

static void qs_thaw(struct ata_port *ap)
{
        u8 __iomem *mmio_base = qs_mmio_base(ap->host);

        qs_enter_reg_mode(ap);
        writeb(1, mmio_base + QS_HCT_CTRL); /* enable host interrupts */
}

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

        qs_reset_channel_logic(ap);
        return ata_sff_prereset(link, deadline);
}

static int qs_scr_read(struct ata_link *link, unsigned int sc_reg, u32 *val)
{
        if (sc_reg > SCR_CONTROL)
                return -EINVAL;
        *val = readl(link->ap->ioaddr.scr_addr + (sc_reg * 8));
        return 0;
}

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

static int qs_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val)
{
        if (sc_reg > SCR_CONTROL)
                return -EINVAL;
        writel(val, link->ap->ioaddr.scr_addr + (sc_reg * 8));
        return 0;
}

static unsigned int qs_fill_sg(struct ata_queued_cmd *qc)
{
        struct scatterlist *sg;
        struct ata_port *ap = qc->ap;
        struct qs_port_priv *pp = ap->private_data;
        u8 *prd = pp->pkt + QS_CPB_BYTES;
        unsigned int si;

        for_each_sg(qc->sg, sg, qc->n_elem, si) {
                u64 addr;
                u32 len;

                addr = sg_dma_address(sg);
                *(__le64 *)prd = cpu_to_le64(addr);
                prd += sizeof(u64);

                len = sg_dma_len(sg);
                *(__le32 *)prd = cpu_to_le32(len);
                prd += sizeof(u64);

                VPRINTK("PRD[%u] = (0x%llX, 0x%X)\n", si,
                                        (unsigned long long)addr, len);
        }

        return si;
}

static void qs_qc_prep(struct ata_queued_cmd *qc)
{
        struct qs_port_priv *pp = qc->ap->private_data;
        u8 dflags = QS_DF_PORD, *buf = pp->pkt;
        u8 hflags = QS_HF_DAT | QS_HF_IEN | QS_HF_VLD;
        u64 addr;
        unsigned int nelem;

        VPRINTK("ENTER\n");

        qs_enter_reg_mode(qc->ap);
        if (qc->tf.protocol != ATA_PROT_DMA)
                return;

        nelem = qs_fill_sg(qc);

        if ((qc->tf.flags & ATA_TFLAG_WRITE))
                hflags |= QS_HF_DIRO;
        if ((qc->tf.flags & ATA_TFLAG_LBA48))
                dflags |= QS_DF_ELBA;

        /* host control block (HCB) */
        buf[ 0] = QS_HCB_HDR;
        buf[ 1] = hflags;
        *(__le32 *)(&buf[ 4]) = cpu_to_le32(qc->nbytes);
        *(__le32 *)(&buf[ 8]) = cpu_to_le32(nelem);
        addr = ((u64)pp->pkt_dma) + QS_CPB_BYTES;
        *(__le64 *)(&buf[16]) = cpu_to_le64(addr);

        /* device control block (DCB) */
        buf[24] = QS_DCB_HDR;
        buf[28] = dflags;

        /* frame information structure (FIS) */
        ata_tf_to_fis(&qc->tf, 0, 1, &buf[32]);
}

static inline void qs_packet_start(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        u8 __iomem *chan = qs_mmio_base(ap->host) + (ap->port_no * 0x4000);

        VPRINTK("ENTER, ap %p\n", ap);

        writeb(QS_CTR0_CLER, chan + QS_CCT_CTR0);
        wmb();                             /* flush PRDs and pkt to memory */
        writel(QS_CCF_RUN_PKT, chan + QS_CCT_CFF);
        readl(chan + QS_CCT_CFF);          /* flush */
}

static unsigned int qs_qc_issue(struct ata_queued_cmd *qc)
{
        struct qs_port_priv *pp = qc->ap->private_data;

        switch (qc->tf.protocol) {
        case ATA_PROT_DMA:
                pp->state = qs_state_pkt;
                qs_packet_start(qc);
                return 0;

        case ATAPI_PROT_DMA:
                BUG();
                break;

        default:
                break;
        }

        pp->state = qs_state_mmio;
        return ata_sff_qc_issue(qc);
}

static void qs_do_or_die(struct ata_queued_cmd *qc, u8 status)
{
        qc->err_mask |= ac_err_mask(status);

        if (!qc->err_mask) {
                ata_qc_complete(qc);
        } else {
                struct ata_port    *ap  = qc->ap;
                struct ata_eh_info *ehi = &ap->link.eh_info;

                ata_ehi_clear_desc(ehi);
                ata_ehi_push_desc(ehi, "status 0x%02X", status);

                if (qc->err_mask == AC_ERR_DEV)
                        ata_port_abort(ap);
                else
                        ata_port_freeze(ap);
        }
}

static inline unsigned int qs_intr_pkt(struct ata_host *host)
{
        unsigned int handled = 0;
        u8 sFFE;
        u8 __iomem *mmio_base = qs_mmio_base(host);

        do {
                u32 sff0 = readl(mmio_base + QS_HST_SFF);
                u32 sff1 = readl(mmio_base + QS_HST_SFF + 4);
                u8 sEVLD = (sff1 >> 30) & 0x01; /* valid flag */
                sFFE  = sff1 >> 31;             /* empty flag */

                if (sEVLD) {
                        u8 sDST = sff0 >> 16;   /* dev status */
                        u8 sHST = sff1 & 0x3f;  /* host status */
                        unsigned int port_no = (sff1 >> 8) & 0x03;
                        struct ata_port *ap = host->ports[port_no];
                        struct qs_port_priv *pp = ap->private_data;
                        struct ata_queued_cmd *qc;

                        DPRINTK("SFF=%08x%08x: sCHAN=%u sHST=%d sDST=%02x\n",
                                        sff1, sff0, port_no, sHST, sDST);
                        handled = 1;
                        if (!pp || pp->state != qs_state_pkt)
                                continue;
                        qc = ata_qc_from_tag(ap, ap->link.active_tag);
                        if (qc && (!(qc->tf.flags & ATA_TFLAG_POLLING))) {
                                switch (sHST) {
                                case 0: /* successful CPB */
                                case 3: /* device error */
                                        qs_enter_reg_mode(qc->ap);
                                        qs_do_or_die(qc, sDST);
                                        break;
                                default:
                                        break;
                                }
                        }
                }
        } while (!sFFE);
        return handled;
}

static inline unsigned int qs_intr_mmio(struct ata_host *host)
{
        unsigned int handled = 0, port_no;

        for (port_no = 0; port_no < host->n_ports; ++port_no) {
                struct ata_port *ap = host->ports[port_no];
                struct qs_port_priv *pp = ap->private_data;
                struct ata_queued_cmd *qc;

                qc = ata_qc_from_tag(ap, ap->link.active_tag);
                if (!qc) {
                        /*
                         * The qstor hardware generates spurious
                         * interrupts from time to time when switching
                         * in and out of packet mode.  There's no
                         * obvious way to know if we're here now due
                         * to that, so just ack the irq and pretend we
                         * knew it was ours.. (ugh).  This does not
                         * affect packet mode.
                         */
                        ata_sff_check_status(ap);
                        handled = 1;
                        continue;
                }

                if (!pp || pp->state != qs_state_mmio)
                        continue;
                if (!(qc->tf.flags & ATA_TFLAG_POLLING))
                        handled |= ata_sff_port_intr(ap, qc);
        }
        return handled;
}

static irqreturn_t qs_intr(int irq, void *dev_instance)
{
        struct ata_host *host = dev_instance;
        unsigned int handled = 0;
        unsigned long flags;

        VPRINTK("ENTER\n");

        spin_lock_irqsave(&host->lock, flags);
        handled  = qs_intr_pkt(host) | qs_intr_mmio(host);
        spin_unlock_irqrestore(&host->lock, flags);

        VPRINTK("EXIT\n");

        return IRQ_RETVAL(handled);
}

static void qs_ata_setup_port(struct ata_ioports *port, void __iomem *base)
{
        port->cmd_addr          =
        port->data_addr         = base + 0x400;
        port->error_addr        =
        port->feature_addr      = base + 0x408; /* hob_feature = 0x409 */
        port->nsect_addr        = base + 0x410; /* hob_nsect   = 0x411 */
        port->lbal_addr         = base + 0x418; /* hob_lbal    = 0x419 */
        port->lbam_addr         = base + 0x420; /* hob_lbam    = 0x421 */
        port->lbah_addr         = base + 0x428; /* hob_lbah    = 0x429 */
        port->device_addr       = base + 0x430;
        port->status_addr       =
        port->command_addr      = base + 0x438;
        port->altstatus_addr    =
        port->ctl_addr          = base + 0x440;
        port->scr_addr          = base + 0xc00;
}

static int qs_port_start(struct ata_port *ap)
{
        struct device *dev = ap->host->dev;
        struct qs_port_priv *pp;
        void __iomem *mmio_base = qs_mmio_base(ap->host);
        void __iomem *chan = mmio_base + (ap->port_no * 0x4000);
        u64 addr;

        pp = devm_kzalloc(dev, sizeof(*pp), GFP_KERNEL);
        if (!pp)
                return -ENOMEM;
        pp->pkt = dmam_alloc_coherent(dev, QS_PKT_BYTES, &pp->pkt_dma,
                                      GFP_KERNEL);
        if (!pp->pkt)
                return -ENOMEM;
        memset(pp->pkt, 0, QS_PKT_BYTES);
        ap->private_data = pp;

        qs_enter_reg_mode(ap);
        addr = (u64)pp->pkt_dma;
        writel((u32) addr,        chan + QS_CCF_CPBA);
        writel((u32)(addr >> 32), chan + QS_CCF_CPBA + 4);
        return 0;
}

static void qs_host_stop(struct ata_host *host)
{
        void __iomem *mmio_base = qs_mmio_base(host);

        writeb(0, mmio_base + QS_HCT_CTRL); /* disable host interrupts */
        writeb(QS_CNFG3_GSRST, mmio_base + QS_HCF_CNFG3); /* global reset */
}

static void qs_host_init(struct ata_host *host, unsigned int chip_id)
{
        void __iomem *mmio_base = host->iomap[QS_MMIO_BAR];
        unsigned int port_no;

        writeb(0, mmio_base + QS_HCT_CTRL); /* disable host interrupts */
        writeb(QS_CNFG3_GSRST, mmio_base + QS_HCF_CNFG3); /* global reset */

        /* reset each channel in turn */
        for (port_no = 0; port_no < host->n_ports; ++port_no) {
                u8 __iomem *chan = mmio_base + (port_no * 0x4000);
                writeb(QS_CTR1_RDEV|QS_CTR1_RCHN, chan + QS_CCT_CTR1);
                writeb(QS_CTR0_REG, chan + QS_CCT_CTR0);
                readb(chan + QS_CCT_CTR0);        /* flush */
        }
        writeb(QS_SERD3_PHY_ENA, mmio_base + QS_HVS_SERD3); /* enable phy */

        for (port_no = 0; port_no < host->n_ports; ++port_no) {
                u8 __iomem *chan = mmio_base + (port_no * 0x4000);
                /* set FIFO depths to same settings as Windows driver */
                writew(32, chan + QS_CFC_HUFT);
                writew(32, chan + QS_CFC_HDFT);
                writew(10, chan + QS_CFC_DUFT);
                writew( 8, chan + QS_CFC_DDFT);
                /* set CPB size in bytes, as a power of two */
                writeb(QS_CPB_ORDER,    chan + QS_CCF_CSEP);
        }
        writeb(1, mmio_base + QS_HCT_CTRL); /* enable host interrupts */
}

/*
 * The QStor understands 64-bit buses, and uses 64-bit fields
 * for DMA pointers regardless of bus width.  We just have to
 * make sure our DMA masks are set appropriately for whatever
 * bridge lies between us and the QStor, and then the DMA mapping
 * code will ensure we only ever "see" appropriate buffer addresses.
 * If we're 32-bit limited somewhere, then our 64-bit fields will
 * just end up with zeros in the upper 32-bits, without any special
 * logic required outside of this routine (below).
 */
static int qs_set_dma_masks(struct pci_dev *pdev, void __iomem *mmio_base)
{
        u32 bus_info = readl(mmio_base + QS_HID_HPHY);
        int rc, have_64bit_bus = (bus_info & QS_HPHY_64BIT);

        if (have_64bit_bus &&
            !dma_set_mask(&pdev->dev, DMA_BIT_MASK(64))) {
                rc = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(64));
                if (rc) {
                        rc = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
                        if (rc) {
                                dev_err(&pdev->dev,
                                        "64-bit DMA enable failed\n");
                                return rc;
                        }
                }
        } else {
                rc = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
                if (rc) {
                        dev_err(&pdev->dev, "32-bit DMA enable failed\n");
                        return rc;
                }
                rc = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
                if (rc) {
                        dev_err(&pdev->dev,
                                "32-bit consistent DMA enable failed\n");
                        return rc;
                }
        }
        return 0;
}

static int qs_ata_init_one(struct pci_dev *pdev,
                                const struct pci_device_id *ent)
{
        unsigned int board_idx = (unsigned int) ent->driver_data;
        const struct ata_port_info *ppi[] = { &qs_port_info[board_idx], NULL };
        struct ata_host *host;
        int rc, port_no;

        ata_print_version_once(&pdev->dev, DRV_VERSION);

        /* alloc host */
        host = ata_host_alloc_pinfo(&pdev->dev, ppi, QS_PORTS);
        if (!host)
                return -ENOMEM;

        /* acquire resources and fill host */
        rc = pcim_enable_device(pdev);
        if (rc)
                return rc;

        if ((pci_resource_flags(pdev, QS_MMIO_BAR) & IORESOURCE_MEM) == 0)
                return -ENODEV;

        rc = pcim_iomap_regions(pdev, 1 << QS_MMIO_BAR, DRV_NAME);
        if (rc)
                return rc;
        host->iomap = pcim_iomap_table(pdev);

        rc = qs_set_dma_masks(pdev, host->iomap[QS_MMIO_BAR]);
        if (rc)
                return rc;

        for (port_no = 0; port_no < host->n_ports; ++port_no) {
                struct ata_port *ap = host->ports[port_no];
                unsigned int offset = port_no * 0x4000;
                void __iomem *chan = host->iomap[QS_MMIO_BAR] + offset;

                qs_ata_setup_port(&ap->ioaddr, chan);

                ata_port_pbar_desc(ap, QS_MMIO_BAR, -1, "mmio");
                ata_port_pbar_desc(ap, QS_MMIO_BAR, offset, "port");
        }

        /* initialize adapter */
        qs_host_init(host, board_idx);

        pci_set_master(pdev);
        return ata_host_activate(host, pdev->irq, qs_intr, IRQF_SHARED,
                                 &qs_ata_sht);
}

module_pci_driver(qs_ata_pci_driver);

MODULE_AUTHOR("Mark Lord");
MODULE_DESCRIPTION("Pacific Digital Corporation QStor SATA low-level driver");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pci, qs_ata_pci_tbl);
MODULE_VERSION(DRV_VERSION);