xref: /kernel/linux/linux-6.6/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 - 2012 Cavium Inc.
 * Copyright (C) 2008 Wind River Systems
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/libata.h>
#include <linux/hrtimer.h>
#include <linux/slab.h>
#include <linux/irq.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <scsi/scsi_host.h>
#include <trace/events/libata.h>
#include <asm/byteorder.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	"2.2"

/* Poll interval in nS. */
#define OCTEON_CF_BUSY_POLL_INTERVAL 500000

#define DMA_CFG 0
#define DMA_TIM 0x20
#define DMA_INT 0x38
#define DMA_INT_EN 0x50

struct octeon_cf_port {
	struct hrtimer delayed_finish;
	struct ata_port *ap;
	int dma_finished;
	void		*c0;
	unsigned int cs0;
	unsigned int cs1;
	bool is_true_ide;
	u64 dma_base;
};

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

static int enable_dma;
module_param(enable_dma, int, 0444);
MODULE_PARM_DESC(enable_dma,
		 "Enable use of DMA on interfaces that support it (0=no dma [default], 1=use dma)");

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

static void octeon_cf_set_boot_reg_cfg(int cs, unsigned int multiplier)
{
	union cvmx_mio_boot_reg_cfgx reg_cfg;
	unsigned int tim_mult;

	switch (multiplier) {
	case 8:
		tim_mult = 3;
		break;
	case 4:
		tim_mult = 0;
		break;
	case 2:
		tim_mult = 2;
		break;
	default:
		tim_mult = 1;
		break;
	}

	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 = tim_mult;	/* Timing mutiplier */
	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_port *cf_port = ap->private_data;
	union cvmx_mio_boot_reg_timx reg_tim;
	int T;
	struct ata_timing timing;

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

	/*
	 * A divisor value of four will overflow the timing fields at
	 * clock rates greater than 800MHz
	 */
	if (octeon_get_io_clock_rate() <= 800000000)
		div = 4;
	else
		div = 8;
	T = (int)((1000000000000LL * div) / octeon_get_io_clock_rate());

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

	t2 = timing.active;
	if (t2)
		t2--;

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

	pause = (int)timing.cycle - (int)timing.active -
		(int)timing.setup - trh;
	if (pause < 0)
		pause = 0;
	if (pause)
		pause--;

	octeon_cf_set_boot_reg_cfg(cf_port->cs0, div);
	if (cf_port->is_true_ide)
		/* True IDE mode, program both chip selects.  */
		octeon_cf_set_boot_reg_cfg(cf_port->cs1, div);


	use_iordy = ata_pio_need_iordy(dev);

	reg_tim.u64 = cvmx_read_csr(CVMX_MIO_BOOT_REG_TIMX(cf_port->cs0));
	/* 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(div, 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(cf_port->cs0), reg_tim.u64);
	if (cf_port->is_true_ide)
		/* True IDE mode, program both chip selects.  */
		cvmx_write_csr(CVMX_MIO_BOOT_REG_TIMX(cf_port->cs1),
			       reg_tim.u64);
}

static void octeon_cf_set_dmamode(struct ata_port *ap, struct ata_device *dev)
{
	struct octeon_cf_port *cf_port = ap->private_data;
	union cvmx_mio_boot_pin_defs pin_defs;
	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;
	int c;

	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_io_clock_rate() / 1000000); /* Tz */

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

	pin_defs.u64 = cvmx_read_csr(CVMX_MIO_BOOT_PIN_DEFS);

	/* DMA channel number. */
	c = (cf_port->dma_base & 8) >> 3;

	/* Invert the polarity if the default is 0*/
	dma_tim.s.dmack_pi = (pin_defs.u64 & (1ull << (11 + c))) ? 0 : 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);

	ata_dev_dbg(dev, "ns to ticks (mult %d) of %d is: %d\n", tim_mult, 60,
		 ns_to_tim_reg(tim_mult, 60));
	ata_dev_dbg(dev, "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(cf_port->dma_base + DMA_TIM, dma_tim.u64);
}

/*
 * Handle an 8 bit I/O request.
 *
 * @qc:         Queued command
 * @buffer:     Data buffer
 * @buflen:     Length of the buffer.
 * @rw:         True to write.
 */
static unsigned int octeon_cf_data_xfer8(struct ata_queued_cmd *qc,
					 unsigned char *buffer,
					 unsigned int buflen,
					 int rw)
{
	struct ata_port *ap		= qc->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.
 *
 * @qc:         Queued command
 * @buffer:     Data buffer
 * @buflen:     Length of the buffer.
 * @rw:         True to write.
 */
static unsigned int octeon_cf_data_xfer16(struct ata_queued_cmd *qc,
					  unsigned char *buffer,
					  unsigned int buflen,
					  int rw)
{
	struct ata_port *ap		= qc->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->error = 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->status = 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;

	__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);
	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);
	}
	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);
	}
	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 = 0;

	if (tf->flags & ATA_TFLAG_DEVICE)
		blob = tf->device;

	blob |= (tf->command << 8);
	__raw_writew(blob, base + 6);

	ata_wait_idle(ap);
}

static void octeon_cf_ata_port_noaction(struct ata_port *ap)
{
}

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;
	/* issue r/w command */
	qc->cursg = qc->sg;
	cf_port->dma_finished = 0;
	ap->ops->sff_exec_command(ap, &qc->tf);
}

/*
 * 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_port *cf_port = qc->ap->private_data;
	union cvmx_mio_boot_dma_cfgx mio_boot_dma_cfg;
	union cvmx_mio_boot_dma_intx mio_boot_dma_int;
	struct scatterlist *sg;

	/* 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(cf_port->dma_base + DMA_INT, mio_boot_dma_int.u64);

	/* Enable the interrupt.  */
	cvmx_write_csr(cf_port->dma_base + DMA_INT_EN, mio_boot_dma_int.u64);

	/* Set the direction of the DMA */
	mio_boot_dma_cfg.u64 = 0;
#ifdef __LITTLE_ENDIAN
	mio_boot_dma_cfg.s.endian = 1;
#endif
	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);

	cvmx_write_csr(cf_port->dma_base + DMA_CFG, 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_port *cf_port = ap->private_data;
	union cvmx_mio_boot_dma_cfgx dma_cfg;
	union cvmx_mio_boot_dma_intx dma_int;
	u8 status;

	trace_ata_bmdma_stop(ap, &qc->tf, qc->tag);

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

	dma_cfg.u64 = cvmx_read_csr(cf_port->dma_base + DMA_CFG);
	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(cf_port->dma_base + DMA_CFG, dma_cfg.u64);

	/* Disable the interrupt.  */
	dma_int.u64 = 0;
	cvmx_write_csr(cf_port->dma_base + DMA_INT_EN, dma_int.u64);

	/* Clear the DMA complete status */
	dma_int.s.done = 1;
	cvmx_write_csr(cf_port->dma_base + DMA_INT, 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);

	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;

		ap = host->ports[i];
		cf_port = ap->private_data;

		dma_int.u64 = cvmx_read_csr(cf_port->dma_base + DMA_INT);
		dma_cfg.u64 = cvmx_read_csr(cf_port->dma_base + DMA_CFG);

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

		if (!qc || (qc->tf.flags & ATA_TFLAG_POLLING))
			continue;

		if (dma_int.s.done && !dma_cfg.s.en) {
			if (!sg_is_last(qc->cursg)) {
				qc->cursg = sg_next(qc->cursg);
				handled = 1;
				trace_ata_bmdma_start(ap, &qc->tf, qc->tag);
				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(cf_port->dma_base + DMA_INT,
				       dma_int.u64);
			hrtimer_start_range_ns(&cf_port->delayed_finish,
					       ns_to_ktime(OCTEON_CF_BUSY_POLL_INTERVAL),
					       OCTEON_CF_BUSY_POLL_INTERVAL / 5,
					       HRTIMER_MODE_REL);
			handled = 1;
		} else {
			handled |= octeon_cf_dma_finished(ap, qc);
		}
	}
	spin_unlock_irqrestore(&host->lock, flags);
	return IRQ_RETVAL(handled);
}

static enum hrtimer_restart octeon_cf_delayed_finish(struct hrtimer *hrt)
{
	struct octeon_cf_port *cf_port = container_of(hrt,
						      struct octeon_cf_port,
						      delayed_finish);
	struct ata_port *ap = cf_port->ap;
	struct ata_host *host = ap->host;
	struct ata_queued_cmd *qc;
	unsigned long flags;
	u8 status;
	enum hrtimer_restart rv = HRTIMER_NORESTART;

	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. */
		hrtimer_forward_now(hrt,
				    ns_to_ktime(OCTEON_CF_BUSY_POLL_INTERVAL));
		rv = HRTIMER_RESTART;
		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);
	return rv;
}

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);

		trace_ata_tf_load(ap, &qc->tf);
		ap->ops->sff_tf_load(ap, &qc->tf);  /* load tf registers */
		trace_ata_bmdma_setup(ap, &qc->tf, qc->tag);
		octeon_cf_dma_setup(qc);	    /* set up dma */
		trace_ata_bmdma_start(ap, &qc->tf, qc->tag);
		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_ata_port_noaction,
	.sff_irq_clear		= octeon_cf_ata_port_noaction,
	.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 octeon_cf_probe(struct platform_device *pdev)
{
	struct resource *res_cs0, *res_cs1;

	bool is_16bit;
	u64 reg;
	struct device_node *node;
	void __iomem *cs0;
	void __iomem *cs1 = NULL;
	struct ata_host *host;
	struct ata_port *ap;
	int irq = 0;
	irq_handler_t irq_handler = NULL;
	void __iomem *base;
	struct octeon_cf_port *cf_port;
	u32 bus_width;
	int rv;

	node = pdev->dev.of_node;
	if (node == NULL)
		return -EINVAL;

	cf_port = devm_kzalloc(&pdev->dev, sizeof(*cf_port), GFP_KERNEL);
	if (!cf_port)
		return -ENOMEM;

	cf_port->is_true_ide = of_property_read_bool(node, "cavium,true-ide");

	if (of_property_read_u32(node, "cavium,bus-width", &bus_width) == 0)
		is_16bit = (bus_width == 16);
	else
		is_16bit = false;

	rv = of_property_read_reg(node, 0, &reg, NULL);
	if (rv < 0)
		return rv;
	cf_port->cs0 = upper_32_bits(reg);

	if (cf_port->is_true_ide) {
		struct device_node *dma_node;
		dma_node = of_parse_phandle(node,
					    "cavium,dma-engine-handle", 0);
		if (dma_node) {
			struct platform_device *dma_dev;
			dma_dev = of_find_device_by_node(dma_node);
			if (dma_dev) {
				struct resource *res_dma;
				int i;
				res_dma = platform_get_resource(dma_dev, IORESOURCE_MEM, 0);
				if (!res_dma) {
					put_device(&dma_dev->dev);
					of_node_put(dma_node);
					return -EINVAL;
				}
				cf_port->dma_base = (u64)devm_ioremap(&pdev->dev, res_dma->start,
									 resource_size(res_dma));
				if (!cf_port->dma_base) {
					put_device(&dma_dev->dev);
					of_node_put(dma_node);
					return -EINVAL;
				}

				i = platform_get_irq(dma_dev, 0);
				if (i > 0) {
					irq = i;
					irq_handler = octeon_cf_interrupt;
				}
				put_device(&dma_dev->dev);
			}
			of_node_put(dma_node);
		}
		res_cs1 = platform_get_resource(pdev, IORESOURCE_MEM, 1);
		if (!res_cs1)
			return -EINVAL;

		cs1 = devm_ioremap(&pdev->dev, res_cs1->start,
					   resource_size(res_cs1));
		if (!cs1)
			return -EINVAL;

		rv = of_property_read_reg(node, 1, &reg, NULL);
		if (rv < 0)
			return rv;
		cf_port->cs1 = upper_32_bits(reg);
	}

	res_cs0 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res_cs0)
		return -EINVAL;

	cs0 = devm_ioremap(&pdev->dev, res_cs0->start,
				   resource_size(res_cs0));
	if (!cs0)
		return -ENOMEM;

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

	ap = host->ports[0];
	ap->private_data = cf_port;
	pdev->dev.platform_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;

	if (!is_16bit) {
		base = cs0 + 0x800;
		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 (cf_port->is_true_ide) {
		base = cs0;
		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	= enable_dma ? ATA_MWDMA4 : 0;

		/* True IDE mode needs a timer to poll for not-busy.  */
		hrtimer_init(&cf_port->delayed_finish, CLOCK_MONOTONIC,
			     HRTIMER_MODE_REL);
		cf_port->delayed_finish.function = octeon_cf_delayed_finish;
	} else {
		/* 16 bit but not True IDE */
		base = cs0 + 0x800;
		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;
	}
	cf_port->c0 = ap->ioaddr.ctl_addr;

	rv = dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
	if (rv)
		return rv;

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

	dev_info(&pdev->dev, "version " DRV_VERSION" %d bit%s.\n",
		 is_16bit ? 16 : 8,
		 cf_port->is_true_ide ? ", True IDE" : "");

	return ata_host_activate(host, irq, irq_handler,
				 IRQF_SHARED, &octeon_cf_sht);
}

static void octeon_cf_shutdown(struct device *dev)
{
	union cvmx_mio_boot_dma_cfgx dma_cfg;
	union cvmx_mio_boot_dma_intx dma_int;

	struct octeon_cf_port *cf_port = dev_get_platdata(dev);

	if (cf_port->dma_base) {
		/* Stop and clear the dma engine.  */
		dma_cfg.u64 = 0;
		dma_cfg.s.size = -1;
		cvmx_write_csr(cf_port->dma_base + DMA_CFG, dma_cfg.u64);

		/* Disable the interrupt.  */
		dma_int.u64 = 0;
		cvmx_write_csr(cf_port->dma_base + DMA_INT_EN, dma_int.u64);

		/* Clear the DMA complete status */
		dma_int.s.done = 1;
		cvmx_write_csr(cf_port->dma_base + DMA_INT, dma_int.u64);

		__raw_writeb(0, cf_port->c0);
		udelay(20);
		__raw_writeb(ATA_SRST, cf_port->c0);
		udelay(20);
		__raw_writeb(0, cf_port->c0);
		mdelay(100);
	}
}

static const struct of_device_id octeon_cf_match[] = {
	{ .compatible = "cavium,ebt3000-compact-flash", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, octeon_cf_match);

static struct platform_driver octeon_cf_driver = {
	.probe		= octeon_cf_probe,
	.driver		= {
		.name	= DRV_NAME,
		.of_match_table = octeon_cf_match,
		.shutdown = octeon_cf_shutdown
	},
};

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);