[SCSI] bnx2fc: Add driver documentation

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / ata / pata_octeon_cf.c

/*
 * Driver for the Octeon bootbus compact flash.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2005 - 2009 Cavium Networks
 * Copyright (C) 2008 Wind River Systems
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/libata.h>
#include <linux/irq.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/workqueue.h>
#include <scsi/scsi_host.h>

#include <asm/octeon/octeon.h>

/*
 * The Octeon bootbus compact flash interface is connected in at least
 * 3 different configurations on various evaluation boards:
 *
 * -- 8  bits no irq, no DMA
 * -- 16 bits no irq, no DMA
 * -- 16 bits True IDE mode with DMA, but no irq.
 *
 * In the last case the DMA engine can generate an interrupt when the
 * transfer is complete.  For the first two cases only PIO is supported.
 *
 */

#define DRV_NAME        "pata_octeon_cf"
#define DRV_VERSION     "2.1"


struct octeon_cf_port {
        struct workqueue_struct *wq;
        struct delayed_work delayed_finish;
        struct ata_port *ap;
        int dma_finished;
};

static struct scsi_host_template octeon_cf_sht = {
        ATA_PIO_SHT(DRV_NAME),
};

/**
 * Convert nanosecond based time to setting used in the
 * boot bus timing register, based on timing multiple
 */
static unsigned int ns_to_tim_reg(unsigned int tim_mult, unsigned int nsecs)
{
        unsigned int val;

        /*
         * Compute # of eclock periods to get desired duration in
         * nanoseconds.
         */
        val = DIV_ROUND_UP(nsecs * (octeon_get_io_clock_rate() / 1000000),
                          1000 * tim_mult);

        return val;
}

static void octeon_cf_set_boot_reg_cfg(int cs)
{
        union cvmx_mio_boot_reg_cfgx reg_cfg;
        reg_cfg.u64 = cvmx_read_csr(CVMX_MIO_BOOT_REG_CFGX(cs));
        reg_cfg.s.dmack = 0;    /* Don't assert DMACK on access */
        reg_cfg.s.tim_mult = 2; /* Timing mutiplier 2x */
        reg_cfg.s.rd_dly = 0;   /* Sample on falling edge of BOOT_OE */
        reg_cfg.s.sam = 0;      /* Don't combine write and output enable */
        reg_cfg.s.we_ext = 0;   /* No write enable extension */
        reg_cfg.s.oe_ext = 0;   /* No read enable extension */
        reg_cfg.s.en = 1;       /* Enable this region */
        reg_cfg.s.orbit = 0;    /* Don't combine with previous region */
        reg_cfg.s.ale = 0;      /* Don't do address multiplexing */
        cvmx_write_csr(CVMX_MIO_BOOT_REG_CFGX(cs), reg_cfg.u64);
}

/**
 * Called after libata determines the needed PIO mode. This
 * function programs the Octeon bootbus regions to support the
 * timing requirements of the PIO mode.
 *
 * @ap:     ATA port information
 * @dev:    ATA device
 */
static void octeon_cf_set_piomode(struct ata_port *ap, struct ata_device *dev)
{
        struct octeon_cf_data *ocd = ap->dev->platform_data;
        union cvmx_mio_boot_reg_timx reg_tim;
        int cs = ocd->base_region;
        int T;
        struct ata_timing timing;

        int use_iordy;
        int trh;
        int pause;
        /* These names are timing parameters from the ATA spec */
        int t1;
        int t2;
        int t2i;

        T = (int)(2000000000000LL / octeon_get_clock_rate());

        if (ata_timing_compute(dev, dev->pio_mode, &timing, T, T))
                BUG();

        t1 = timing.setup;
        if (t1)
                t1--;
        t2 = timing.active;
        if (t2)
                t2--;
        t2i = timing.act8b;
        if (t2i)
                t2i--;

        trh = ns_to_tim_reg(2, 20);
        if (trh)
                trh--;

        pause = timing.cycle - timing.active - timing.setup - trh;
        if (pause)
                pause--;

        octeon_cf_set_boot_reg_cfg(cs);
        if (ocd->dma_engine >= 0)
                /* True IDE mode, program both chip selects.  */
                octeon_cf_set_boot_reg_cfg(cs + 1);


        use_iordy = ata_pio_need_iordy(dev);

        reg_tim.u64 = cvmx_read_csr(CVMX_MIO_BOOT_REG_TIMX(cs));
        /* Disable page mode */
        reg_tim.s.pagem = 0;
        /* Enable dynamic timing */
        reg_tim.s.waitm = use_iordy;
        /* Pages are disabled */
        reg_tim.s.pages = 0;
        /* We don't use multiplexed address mode */
        reg_tim.s.ale = 0;
        /* Not used */
        reg_tim.s.page = 0;
        /* Time after IORDY to coninue to assert the data */
        reg_tim.s.wait = 0;
        /* Time to wait to complete the cycle. */
        reg_tim.s.pause = pause;
        /* How long to hold after a write to de-assert CE. */
        reg_tim.s.wr_hld = trh;
        /* How long to wait after a read to de-assert CE. */
        reg_tim.s.rd_hld = trh;
        /* How long write enable is asserted */
        reg_tim.s.we = t2;
        /* How long read enable is asserted */
        reg_tim.s.oe = t2;
        /* Time after CE that read/write starts */
        reg_tim.s.ce = ns_to_tim_reg(2, 5);
        /* Time before CE that address is valid */
        reg_tim.s.adr = 0;

        /* Program the bootbus region timing for the data port chip select. */
        cvmx_write_csr(CVMX_MIO_BOOT_REG_TIMX(cs), reg_tim.u64);
        if (ocd->dma_engine >= 0)
                /* True IDE mode, program both chip selects.  */
                cvmx_write_csr(CVMX_MIO_BOOT_REG_TIMX(cs + 1), reg_tim.u64);
}

static void octeon_cf_set_dmamode(struct ata_port *ap, struct ata_device *dev)
{
        struct octeon_cf_data *ocd = dev->link->ap->dev->platform_data;
        union cvmx_mio_boot_dma_timx dma_tim;
        unsigned int oe_a;
        unsigned int oe_n;
        unsigned int dma_ackh;
        unsigned int dma_arq;
        unsigned int pause;
        unsigned int T0, Tkr, Td;
        unsigned int tim_mult;

        const struct ata_timing *timing;

        timing = ata_timing_find_mode(dev->dma_mode);
        T0      = timing->cycle;
        Td      = timing->active;
        Tkr     = timing->recover;
        dma_ackh = timing->dmack_hold;

        dma_tim.u64 = 0;
        /* dma_tim.s.tim_mult = 0 --> 4x */
        tim_mult = 4;

        /* not spec'ed, value in eclocks, not affected by tim_mult */
        dma_arq = 8;
        pause = 25 - dma_arq * 1000 /
                (octeon_get_clock_rate() / 1000000); /* Tz */

        oe_a = Td;
        /* Tkr from cf spec, lengthened to meet T0 */
        oe_n = max(T0 - oe_a, Tkr);

        dma_tim.s.dmack_pi = 1;

        dma_tim.s.oe_n = ns_to_tim_reg(tim_mult, oe_n);
        dma_tim.s.oe_a = ns_to_tim_reg(tim_mult, oe_a);

        /*
         * This is tI, C.F. spec. says 0, but Sony CF card requires
         * more, we use 20 nS.
         */
        dma_tim.s.dmack_s = ns_to_tim_reg(tim_mult, 20);
        dma_tim.s.dmack_h = ns_to_tim_reg(tim_mult, dma_ackh);

        dma_tim.s.dmarq = dma_arq;
        dma_tim.s.pause = ns_to_tim_reg(tim_mult, pause);

        dma_tim.s.rd_dly = 0;   /* Sample right on edge */

        /*  writes only */
        dma_tim.s.we_n = ns_to_tim_reg(tim_mult, oe_n);
        dma_tim.s.we_a = ns_to_tim_reg(tim_mult, oe_a);

        pr_debug("ns to ticks (mult %d) of %d is: %d\n", tim_mult, 60,
                 ns_to_tim_reg(tim_mult, 60));
        pr_debug("oe_n: %d, oe_a: %d, dmack_s: %d, dmack_h: "
                 "%d, dmarq: %d, pause: %d\n",
                 dma_tim.s.oe_n, dma_tim.s.oe_a, dma_tim.s.dmack_s,
                 dma_tim.s.dmack_h, dma_tim.s.dmarq, dma_tim.s.pause);

        cvmx_write_csr(CVMX_MIO_BOOT_DMA_TIMX(ocd->dma_engine),
                       dma_tim.u64);

}

/**
 * Handle an 8 bit I/O request.
 *
 * @dev:        Device to access
 * @buffer:     Data buffer
 * @buflen:     Length of the buffer.
 * @rw:         True to write.
 */
static unsigned int octeon_cf_data_xfer8(struct ata_device *dev,
                                         unsigned char *buffer,
                                         unsigned int buflen,
                                         int rw)
{
        struct ata_port *ap             = dev->link->ap;
        void __iomem *data_addr         = ap->ioaddr.data_addr;
        unsigned long words;
        int count;

        words = buflen;
        if (rw) {
                count = 16;
                while (words--) {
                        iowrite8(*buffer, data_addr);
                        buffer++;
                        /*
                         * Every 16 writes do a read so the bootbus
                         * FIFO doesn't fill up.
                         */
                        if (--count == 0) {
                                ioread8(ap->ioaddr.altstatus_addr);
                                count = 16;
                        }
                }
        } else {
                ioread8_rep(data_addr, buffer, words);
        }
        return buflen;
}

/**
 * Handle a 16 bit I/O request.
 *
 * @dev:        Device to access
 * @buffer:     Data buffer
 * @buflen:     Length of the buffer.
 * @rw:         True to write.
 */
static unsigned int octeon_cf_data_xfer16(struct ata_device *dev,
                                          unsigned char *buffer,
                                          unsigned int buflen,
                                          int rw)
{
        struct ata_port *ap             = dev->link->ap;
        void __iomem *data_addr         = ap->ioaddr.data_addr;
        unsigned long words;
        int count;

        words = buflen / 2;
        if (rw) {
                count = 16;
                while (words--) {
                        iowrite16(*(uint16_t *)buffer, data_addr);
                        buffer += sizeof(uint16_t);
                        /*
                         * Every 16 writes do a read so the bootbus
                         * FIFO doesn't fill up.
                         */
                        if (--count == 0) {
                                ioread8(ap->ioaddr.altstatus_addr);
                                count = 16;
                        }
                }
        } else {
                while (words--) {
                        *(uint16_t *)buffer = ioread16(data_addr);
                        buffer += sizeof(uint16_t);
                }
        }
        /* Transfer trailing 1 byte, if any. */
        if (unlikely(buflen & 0x01)) {
                __le16 align_buf[1] = { 0 };

                if (rw == READ) {
                        align_buf[0] = cpu_to_le16(ioread16(data_addr));
                        memcpy(buffer, align_buf, 1);
                } else {
                        memcpy(align_buf, buffer, 1);
                        iowrite16(le16_to_cpu(align_buf[0]), data_addr);
                }
                words++;
        }
        return buflen;
}

/**
 * Read the taskfile for 16bit non-True IDE only.
 */
static void octeon_cf_tf_read16(struct ata_port *ap, struct ata_taskfile *tf)
{
        u16 blob;
        /* The base of the registers is at ioaddr.data_addr. */
        void __iomem *base = ap->ioaddr.data_addr;

        blob = __raw_readw(base + 0xc);
        tf->feature = blob >> 8;

        blob = __raw_readw(base + 2);
        tf->nsect = blob & 0xff;
        tf->lbal = blob >> 8;

        blob = __raw_readw(base + 4);
        tf->lbam = blob & 0xff;
        tf->lbah = blob >> 8;

        blob = __raw_readw(base + 6);
        tf->device = blob & 0xff;
        tf->command = blob >> 8;

        if (tf->flags & ATA_TFLAG_LBA48) {
                if (likely(ap->ioaddr.ctl_addr)) {
                        iowrite8(tf->ctl | ATA_HOB, ap->ioaddr.ctl_addr);

                        blob = __raw_readw(base + 0xc);
                        tf->hob_feature = blob >> 8;

                        blob = __raw_readw(base + 2);
                        tf->hob_nsect = blob & 0xff;
                        tf->hob_lbal = blob >> 8;

                        blob = __raw_readw(base + 4);
                        tf->hob_lbam = blob & 0xff;
                        tf->hob_lbah = blob >> 8;

                        iowrite8(tf->ctl, ap->ioaddr.ctl_addr);
                        ap->last_ctl = tf->ctl;
                } else {
                        WARN_ON(1);
                }
        }
}

static u8 octeon_cf_check_status16(struct ata_port *ap)
{
        u16 blob;
        void __iomem *base = ap->ioaddr.data_addr;

        blob = __raw_readw(base + 6);
        return blob >> 8;
}

static int octeon_cf_softreset16(struct ata_link *link, unsigned int *classes,
                                 unsigned long deadline)
{
        struct ata_port *ap = link->ap;
        void __iomem *base = ap->ioaddr.data_addr;
        int rc;
        u8 err;

        DPRINTK("about to softreset\n");
        __raw_writew(ap->ctl, base + 0xe);
        udelay(20);
        __raw_writew(ap->ctl | ATA_SRST, base + 0xe);
        udelay(20);
        __raw_writew(ap->ctl, base + 0xe);

        rc = ata_sff_wait_after_reset(link, 1, deadline);
        if (rc) {
                ata_link_err(link, "SRST failed (errno=%d)\n", rc);
                return rc;
        }

        /* determine by signature whether we have ATA or ATAPI devices */
        classes[0] = ata_sff_dev_classify(&link->device[0], 1, &err);
        DPRINTK("EXIT, classes[0]=%u [1]=%u\n", classes[0], classes[1]);
        return 0;
}

/**
 * Load the taskfile for 16bit non-True IDE only.  The device_addr is
 * not loaded, we do this as part of octeon_cf_exec_command16.
 */
static void octeon_cf_tf_load16(struct ata_port *ap,
                                const struct ata_taskfile *tf)
{
        unsigned int is_addr = tf->flags & ATA_TFLAG_ISADDR;
        /* The base of the registers is at ioaddr.data_addr. */
        void __iomem *base = ap->ioaddr.data_addr;

        if (tf->ctl != ap->last_ctl) {
                iowrite8(tf->ctl, ap->ioaddr.ctl_addr);
                ap->last_ctl = tf->ctl;
                ata_wait_idle(ap);
        }
        if (is_addr && (tf->flags & ATA_TFLAG_LBA48)) {
                __raw_writew(tf->hob_feature << 8, base + 0xc);
                __raw_writew(tf->hob_nsect | tf->hob_lbal << 8, base + 2);
                __raw_writew(tf->hob_lbam | tf->hob_lbah << 8, base + 4);
                VPRINTK("hob: feat 0x%X nsect 0x%X, lba 0x%X 0x%X 0x%X\n",
                        tf->hob_feature,
                        tf->hob_nsect,
                        tf->hob_lbal,
                        tf->hob_lbam,
                        tf->hob_lbah);
        }
        if (is_addr) {
                __raw_writew(tf->feature << 8, base + 0xc);
                __raw_writew(tf->nsect | tf->lbal << 8, base + 2);
                __raw_writew(tf->lbam | tf->lbah << 8, base + 4);
                VPRINTK("feat 0x%X nsect 0x%X, lba 0x%X 0x%X 0x%X\n",
                        tf->feature,
                        tf->nsect,
                        tf->lbal,
                        tf->lbam,
                        tf->lbah);
        }
        ata_wait_idle(ap);
}


static void octeon_cf_dev_select(struct ata_port *ap, unsigned int device)
{
/*  There is only one device, do nothing. */
        return;
}

/*
 * Issue ATA command to host controller.  The device_addr is also sent
 * as it must be written in a combined write with the command.
 */
static void octeon_cf_exec_command16(struct ata_port *ap,
                                const struct ata_taskfile *tf)
{
        /* The base of the registers is at ioaddr.data_addr. */
        void __iomem *base = ap->ioaddr.data_addr;
        u16 blob;

        if (tf->flags & ATA_TFLAG_DEVICE) {
                VPRINTK("device 0x%X\n", tf->device);
                blob = tf->device;
        } else {
                blob = 0;
        }

        DPRINTK("ata%u: cmd 0x%X\n", ap->print_id, tf->command);
        blob |= (tf->command << 8);
        __raw_writew(blob, base + 6);


        ata_wait_idle(ap);
}

static void octeon_cf_irq_on(struct ata_port *ap)
{
}

static void octeon_cf_irq_clear(struct ata_port *ap)
{
        return;
}

static void octeon_cf_dma_setup(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        struct octeon_cf_port *cf_port;

        cf_port = ap->private_data;
        DPRINTK("ENTER\n");
        /* issue r/w command */
        qc->cursg = qc->sg;
        cf_port->dma_finished = 0;
        ap->ops->sff_exec_command(ap, &qc->tf);
        DPRINTK("EXIT\n");
}

/**
 * Start a DMA transfer that was already setup
 *
 * @qc:     Information about the DMA
 */
static void octeon_cf_dma_start(struct ata_queued_cmd *qc)
{
        struct octeon_cf_data *ocd = qc->ap->dev->platform_data;
        union cvmx_mio_boot_dma_cfgx mio_boot_dma_cfg;
        union cvmx_mio_boot_dma_intx mio_boot_dma_int;
        struct scatterlist *sg;

        VPRINTK("%d scatterlists\n", qc->n_elem);

        /* Get the scatter list entry we need to DMA into */
        sg = qc->cursg;
        BUG_ON(!sg);

        /*
         * Clear the DMA complete status.
         */
        mio_boot_dma_int.u64 = 0;
        mio_boot_dma_int.s.done = 1;
        cvmx_write_csr(CVMX_MIO_BOOT_DMA_INTX(ocd->dma_engine),
                       mio_boot_dma_int.u64);

        /* Enable the interrupt.  */
        cvmx_write_csr(CVMX_MIO_BOOT_DMA_INT_ENX(ocd->dma_engine),
                       mio_boot_dma_int.u64);

        /* Set the direction of the DMA */
        mio_boot_dma_cfg.u64 = 0;
        mio_boot_dma_cfg.s.en = 1;
        mio_boot_dma_cfg.s.rw = ((qc->tf.flags & ATA_TFLAG_WRITE) != 0);

        /*
         * Don't stop the DMA if the device deasserts DMARQ. Many
         * compact flashes deassert DMARQ for a short time between
         * sectors. Instead of stopping and restarting the DMA, we'll
         * let the hardware do it. If the DMA is really stopped early
         * due to an error condition, a later timeout will force us to
         * stop.
         */
        mio_boot_dma_cfg.s.clr = 0;

        /* Size is specified in 16bit words and minus one notation */
        mio_boot_dma_cfg.s.size = sg_dma_len(sg) / 2 - 1;

        /* We need to swap the high and low bytes of every 16 bits */
        mio_boot_dma_cfg.s.swap8 = 1;

        mio_boot_dma_cfg.s.adr = sg_dma_address(sg);

        VPRINTK("%s %d bytes address=%p\n",
                (mio_boot_dma_cfg.s.rw) ? "write" : "read", sg->length,
                (void *)(unsigned long)mio_boot_dma_cfg.s.adr);

        cvmx_write_csr(CVMX_MIO_BOOT_DMA_CFGX(ocd->dma_engine),
                       mio_boot_dma_cfg.u64);
}

/**
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 *
 */
static unsigned int octeon_cf_dma_finished(struct ata_port *ap,
                                        struct ata_queued_cmd *qc)
{
        struct ata_eh_info *ehi = &ap->link.eh_info;
        struct octeon_cf_data *ocd = ap->dev->platform_data;
        union cvmx_mio_boot_dma_cfgx dma_cfg;
        union cvmx_mio_boot_dma_intx dma_int;
        struct octeon_cf_port *cf_port;
        u8 status;

        VPRINTK("ata%u: protocol %d task_state %d\n",
                ap->print_id, qc->tf.protocol, ap->hsm_task_state);


        if (ap->hsm_task_state != HSM_ST_LAST)
                return 0;

        cf_port = ap->private_data;

        dma_cfg.u64 = cvmx_read_csr(CVMX_MIO_BOOT_DMA_CFGX(ocd->dma_engine));
        if (dma_cfg.s.size != 0xfffff) {
                /* Error, the transfer was not complete.  */
                qc->err_mask |= AC_ERR_HOST_BUS;
                ap->hsm_task_state = HSM_ST_ERR;
        }

        /* Stop and clear the dma engine.  */
        dma_cfg.u64 = 0;
        dma_cfg.s.size = -1;
        cvmx_write_csr(CVMX_MIO_BOOT_DMA_CFGX(ocd->dma_engine), dma_cfg.u64);

        /* Disable the interrupt.  */
        dma_int.u64 = 0;
        cvmx_write_csr(CVMX_MIO_BOOT_DMA_INT_ENX(ocd->dma_engine), dma_int.u64);

        /* Clear the DMA complete status */
        dma_int.s.done = 1;
        cvmx_write_csr(CVMX_MIO_BOOT_DMA_INTX(ocd->dma_engine), dma_int.u64);

        status = ap->ops->sff_check_status(ap);

        ata_sff_hsm_move(ap, qc, status, 0);

        if (unlikely(qc->err_mask) && (qc->tf.protocol == ATA_PROT_DMA))
                ata_ehi_push_desc(ehi, "DMA stat 0x%x", status);

        return 1;
}

/*
 * Check if any queued commands have more DMAs, if so start the next
 * transfer, else do end of transfer handling.
 */
static irqreturn_t octeon_cf_interrupt(int irq, void *dev_instance)
{
        struct ata_host *host = dev_instance;
        struct octeon_cf_port *cf_port;
        int i;
        unsigned int handled = 0;
        unsigned long flags;

        spin_lock_irqsave(&host->lock, flags);

        DPRINTK("ENTER\n");
        for (i = 0; i < host->n_ports; i++) {
                u8 status;
                struct ata_port *ap;
                struct ata_queued_cmd *qc;
                union cvmx_mio_boot_dma_intx dma_int;
                union cvmx_mio_boot_dma_cfgx dma_cfg;
                struct octeon_cf_data *ocd;

                ap = host->ports[i];
                ocd = ap->dev->platform_data;
                cf_port = ap->private_data;
                dma_int.u64 =
                        cvmx_read_csr(CVMX_MIO_BOOT_DMA_INTX(ocd->dma_engine));
                dma_cfg.u64 =
                        cvmx_read_csr(CVMX_MIO_BOOT_DMA_CFGX(ocd->dma_engine));

                qc = ata_qc_from_tag(ap, ap->link.active_tag);

                if (qc && !(qc->tf.flags & ATA_TFLAG_POLLING)) {
                        if (dma_int.s.done && !dma_cfg.s.en) {
                                if (!sg_is_last(qc->cursg)) {
                                        qc->cursg = sg_next(qc->cursg);
                                        handled = 1;
                                        octeon_cf_dma_start(qc);
                                        continue;
                                } else {
                                        cf_port->dma_finished = 1;
                                }
                        }
                        if (!cf_port->dma_finished)
                                continue;
                        status = ioread8(ap->ioaddr.altstatus_addr);
                        if (status & (ATA_BUSY | ATA_DRQ)) {
                                /*
                                 * We are busy, try to handle it
                                 * later.  This is the DMA finished
                                 * interrupt, and it could take a
                                 * little while for the card to be
                                 * ready for more commands.
                                 */
                                /* Clear DMA irq. */
                                dma_int.u64 = 0;
                                dma_int.s.done = 1;
                                cvmx_write_csr(CVMX_MIO_BOOT_DMA_INTX(ocd->dma_engine),
                                               dma_int.u64);

                                queue_delayed_work(cf_port->wq,
                                                   &cf_port->delayed_finish, 1);
                                handled = 1;
                        } else {
                                handled |= octeon_cf_dma_finished(ap, qc);
                        }
                }
        }
        spin_unlock_irqrestore(&host->lock, flags);
        DPRINTK("EXIT\n");
        return IRQ_RETVAL(handled);
}

static void octeon_cf_delayed_finish(struct work_struct *work)
{
        struct octeon_cf_port *cf_port = container_of(work,
                                                      struct octeon_cf_port,
                                                      delayed_finish.work);
        struct ata_port *ap = cf_port->ap;
        struct ata_host *host = ap->host;
        struct ata_queued_cmd *qc;
        unsigned long flags;
        u8 status;

        spin_lock_irqsave(&host->lock, flags);

        /*
         * If the port is not waiting for completion, it must have
         * handled it previously.  The hsm_task_state is
         * protected by host->lock.
         */
        if (ap->hsm_task_state != HSM_ST_LAST || !cf_port->dma_finished)
                goto out;

        status = ioread8(ap->ioaddr.altstatus_addr);
        if (status & (ATA_BUSY | ATA_DRQ)) {
                /* Still busy, try again. */
                queue_delayed_work(cf_port->wq,
                                   &cf_port->delayed_finish, 1);
                goto out;
        }
        qc = ata_qc_from_tag(ap, ap->link.active_tag);
        if (qc && !(qc->tf.flags & ATA_TFLAG_POLLING))
                octeon_cf_dma_finished(ap, qc);
out:
        spin_unlock_irqrestore(&host->lock, flags);
}

static void octeon_cf_dev_config(struct ata_device *dev)
{
        /*
         * A maximum of 2^20 - 1 16 bit transfers are possible with
         * the bootbus DMA.  So we need to throttle max_sectors to
         * (2^12 - 1 == 4095) to assure that this can never happen.
         */
        dev->max_sectors = min(dev->max_sectors, 4095U);
}

/*
 * We don't do ATAPI DMA so return 0.
 */
static int octeon_cf_check_atapi_dma(struct ata_queued_cmd *qc)
{
        return 0;
}

static unsigned int octeon_cf_qc_issue(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;

        switch (qc->tf.protocol) {
        case ATA_PROT_DMA:
                WARN_ON(qc->tf.flags & ATA_TFLAG_POLLING);

                ap->ops->sff_tf_load(ap, &qc->tf);  /* load tf registers */
                octeon_cf_dma_setup(qc);            /* set up dma */
                octeon_cf_dma_start(qc);            /* initiate dma */
                ap->hsm_task_state = HSM_ST_LAST;
                break;

        case ATAPI_PROT_DMA:
                dev_err(ap->dev, "Error, ATAPI not supported\n");
                BUG();

        default:
                return ata_sff_qc_issue(qc);
        }

        return 0;
}

static struct ata_port_operations octeon_cf_ops = {
        .inherits               = &ata_sff_port_ops,
        .check_atapi_dma        = octeon_cf_check_atapi_dma,
        .qc_prep                = ata_noop_qc_prep,
        .qc_issue               = octeon_cf_qc_issue,
        .sff_dev_select         = octeon_cf_dev_select,
        .sff_irq_on             = octeon_cf_irq_on,
        .sff_irq_clear          = octeon_cf_irq_clear,
        .cable_detect           = ata_cable_40wire,
        .set_piomode            = octeon_cf_set_piomode,
        .set_dmamode            = octeon_cf_set_dmamode,
        .dev_config             = octeon_cf_dev_config,
};

static int __devinit octeon_cf_probe(struct platform_device *pdev)
{
        struct resource *res_cs0, *res_cs1;

        void __iomem *cs0;
        void __iomem *cs1 = NULL;
        struct ata_host *host;
        struct ata_port *ap;
        struct octeon_cf_data *ocd;
        int irq = 0;
        irq_handler_t irq_handler = NULL;
        void __iomem *base;
        struct octeon_cf_port *cf_port;
        char version[32];

        res_cs0 = platform_get_resource(pdev, IORESOURCE_MEM, 0);

        if (!res_cs0)
                return -EINVAL;

        ocd = pdev->dev.platform_data;

        cs0 = devm_ioremap_nocache(&pdev->dev, res_cs0->start,
                                   resource_size(res_cs0));

        if (!cs0)
                return -ENOMEM;

        /* Determine from availability of DMA if True IDE mode or not */
        if (ocd->dma_engine >= 0) {
                res_cs1 = platform_get_resource(pdev, IORESOURCE_MEM, 1);
                if (!res_cs1)
                        return -EINVAL;

                cs1 = devm_ioremap_nocache(&pdev->dev, res_cs1->start,
                                           resource_size(res_cs1));

                if (!cs1)
                        return -ENOMEM;
        }

        cf_port = kzalloc(sizeof(*cf_port), GFP_KERNEL);
        if (!cf_port)
                return -ENOMEM;

        /* allocate host */
        host = ata_host_alloc(&pdev->dev, 1);
        if (!host)
                goto free_cf_port;

        ap = host->ports[0];
        ap->private_data = cf_port;
        cf_port->ap = ap;
        ap->ops = &octeon_cf_ops;
        ap->pio_mask = ATA_PIO6;
        ap->flags |= ATA_FLAG_NO_ATAPI | ATA_FLAG_PIO_POLLING;

        base = cs0 + ocd->base_region_bias;
        if (!ocd->is16bit) {
                ap->ioaddr.cmd_addr     = base;
                ata_sff_std_ports(&ap->ioaddr);

                ap->ioaddr.altstatus_addr = base + 0xe;
                ap->ioaddr.ctl_addr     = base + 0xe;
                octeon_cf_ops.sff_data_xfer = octeon_cf_data_xfer8;
        } else if (cs1) {
                /* Presence of cs1 indicates True IDE mode.  */
                ap->ioaddr.cmd_addr     = base + (ATA_REG_CMD << 1) + 1;
                ap->ioaddr.data_addr    = base + (ATA_REG_DATA << 1);
                ap->ioaddr.error_addr   = base + (ATA_REG_ERR << 1) + 1;
                ap->ioaddr.feature_addr = base + (ATA_REG_FEATURE << 1) + 1;
                ap->ioaddr.nsect_addr   = base + (ATA_REG_NSECT << 1) + 1;
                ap->ioaddr.lbal_addr    = base + (ATA_REG_LBAL << 1) + 1;
                ap->ioaddr.lbam_addr    = base + (ATA_REG_LBAM << 1) + 1;
                ap->ioaddr.lbah_addr    = base + (ATA_REG_LBAH << 1) + 1;
                ap->ioaddr.device_addr  = base + (ATA_REG_DEVICE << 1) + 1;
                ap->ioaddr.status_addr  = base + (ATA_REG_STATUS << 1) + 1;
                ap->ioaddr.command_addr = base + (ATA_REG_CMD << 1) + 1;
                ap->ioaddr.altstatus_addr = cs1 + (6 << 1) + 1;
                ap->ioaddr.ctl_addr     = cs1 + (6 << 1) + 1;
                octeon_cf_ops.sff_data_xfer = octeon_cf_data_xfer16;

                ap->mwdma_mask  = ATA_MWDMA4;
                irq = platform_get_irq(pdev, 0);
                irq_handler = octeon_cf_interrupt;

                /* True IDE mode needs delayed work to poll for not-busy.  */
                cf_port->wq = create_singlethread_workqueue(DRV_NAME);
                if (!cf_port->wq)
                        goto free_cf_port;
                INIT_DELAYED_WORK(&cf_port->delayed_finish,
                                  octeon_cf_delayed_finish);

        } else {
                /* 16 bit but not True IDE */
                octeon_cf_ops.sff_data_xfer     = octeon_cf_data_xfer16;
                octeon_cf_ops.softreset         = octeon_cf_softreset16;
                octeon_cf_ops.sff_check_status  = octeon_cf_check_status16;
                octeon_cf_ops.sff_tf_read       = octeon_cf_tf_read16;
                octeon_cf_ops.sff_tf_load       = octeon_cf_tf_load16;
                octeon_cf_ops.sff_exec_command  = octeon_cf_exec_command16;

                ap->ioaddr.data_addr    = base + ATA_REG_DATA;
                ap->ioaddr.nsect_addr   = base + ATA_REG_NSECT;
                ap->ioaddr.lbal_addr    = base + ATA_REG_LBAL;
                ap->ioaddr.ctl_addr     = base + 0xe;
                ap->ioaddr.altstatus_addr = base + 0xe;
        }

        ata_port_desc(ap, "cmd %p ctl %p", base, ap->ioaddr.ctl_addr);


        snprintf(version, sizeof(version), "%s %d bit%s",
                 DRV_VERSION,
                 (ocd->is16bit) ? 16 : 8,
                 (cs1) ? ", True IDE" : "");
        ata_print_version_once(&pdev->dev, version);

        return ata_host_activate(host, irq, irq_handler, 0, &octeon_cf_sht);

free_cf_port:
        kfree(cf_port);
        return -ENOMEM;
}

static struct platform_driver octeon_cf_driver = {
        .probe          = octeon_cf_probe,
        .driver         = {
                .name   = DRV_NAME,
                .owner  = THIS_MODULE,
        },
};

static int __init octeon_cf_init(void)
{
        return platform_driver_register(&octeon_cf_driver);
}


MODULE_AUTHOR("David Daney <ddaney@caviumnetworks.com>");
MODULE_DESCRIPTION("low-level driver for Cavium OCTEON Compact Flash PATA");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
MODULE_ALIAS("platform:" DRV_NAME);

module_init(octeon_cf_init);