path: root/sys/dev/ata/ata-usb.c

/*-
 * Copyright (c) 2006 - 2008 Søren Schmidt <sos@FreeBSD.org>
 * All rights reserved.
 *
 * Copyright (c) 2006 Hans Petter Selasky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer,
 *    without modification, immediately at the beginning of the file.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include "usbdevs.h"
#include <dev/usb/usb.h>
#include <dev/usb/usb_mfunc.h>
#include <dev/usb/usb_error.h>

#include <dev/usb/usb_core.h>
#include <dev/usb/usb_util.h>
#include <dev/usb/usb_busdma.h>
#include <dev/usb/usb_request.h>
#include <dev/usb/usb_debug.h>
#include <dev/usb/usb_process.h>
#include <dev/usb/usb_transfer.h>

#include <sys/ata.h>
#include <sys/bio.h>
#include <sys/sema.h>
#include <sys/taskqueue.h>
#include <vm/uma.h>

#include <dev/ata/ata-all.h>
#include <ata_if.h>

#define	ATAUSB_BULK_SIZE (1<<17)

/* Command Block Wrapper */
struct bbb_cbw {
	uint8_t	signature[4];
#define	CBWSIGNATURE		0x43425355

	uint8_t	tag[4];
	uint8_t	transfer_length[4];
	uint8_t	flags;
#define	CBWFLAGS_OUT  		0x00
#define	CBWFLAGS_IN  		0x80

	uint8_t	lun;
	uint8_t	length;
#define	CBWCDBLENGTH     	16

	uint8_t	cdb[CBWCDBLENGTH];
} __packed;

/* Command Status Wrapper */
struct bbb_csw {
	uint8_t	signature[4];
#define	CSWSIGNATURE     	0x53425355

	uint8_t	tag[4];
	uint8_t	residue[4];
	uint8_t	status;
#define	CSWSTATUS_GOOD   	0x0
#define	CSWSTATUS_FAILED 	0x1
#define	CSWSTATUS_PHASE  	0x2
} __packed;

/* USB-ATA 'controller' softc */
struct atausb2_softc {
	struct bbb_cbw cbw;
	struct bbb_csw csw;
	struct mtx locked_mtx;

	struct ata_channel *locked_ch;
	struct ata_channel *restart_ch;
	struct ata_request *ata_request;

#define	ATAUSB_T_BBB_RESET1        0
#define	ATAUSB_T_BBB_RESET2        1
#define	ATAUSB_T_BBB_RESET3        2
#define	ATAUSB_T_BBB_COMMAND       3
#define	ATAUSB_T_BBB_DATA_READ     4
#define	ATAUSB_T_BBB_DATA_RD_CS    5
#define	ATAUSB_T_BBB_DATA_WRITE    6
#define	ATAUSB_T_BBB_DATA_WR_CS    7
#define	ATAUSB_T_BBB_STATUS        8
#define	ATAUSB_T_BBB_MAX           9

#define	ATAUSB_T_MAX ATAUSB_T_BBB_MAX

	struct usb2_xfer *xfer[ATAUSB_T_MAX];
	caddr_t	ata_data;
	device_t dev;

	uint32_t timeout;
	uint32_t ata_donecount;
	uint32_t ata_bytecount;

	uint8_t	last_xfer_no;
	uint8_t	usb2_speed;
	uint8_t	intr_stalled;
	uint8_t	maxlun;
	uint8_t	iface_no;
	uint8_t	status_try;
};

static const int atausbdebug = 0;

/* prototypes */

static device_probe_t atausb2_probe;
static device_attach_t atausb2_attach;
static device_detach_t atausb2_detach;

static usb2_callback_t atausb2_t_bbb_reset1_callback;
static usb2_callback_t atausb2_t_bbb_reset2_callback;
static usb2_callback_t atausb2_t_bbb_reset3_callback;
static usb2_callback_t atausb2_t_bbb_command_callback;
static usb2_callback_t atausb2_t_bbb_data_read_callback;
static usb2_callback_t atausb2_t_bbb_data_rd_cs_callback;
static usb2_callback_t atausb2_t_bbb_data_write_callback;
static usb2_callback_t atausb2_t_bbb_data_wr_cs_callback;
static usb2_callback_t atausb2_t_bbb_status_callback;
static usb2_callback_t atausb2_tr_error;

static void atausb2_cancel_request(struct atausb2_softc *sc);
static void atausb2_transfer_start(struct atausb2_softc *sc, uint8_t xfer_no);
static void atausb2_t_bbb_data_clear_stall_callback(struct usb2_xfer *xfer, uint8_t next_xfer, uint8_t stall_xfer);
static int ata_usbchannel_begin_transaction(struct ata_request *request);
static int ata_usbchannel_end_transaction(struct ata_request *request);

static device_probe_t ata_usbchannel_probe;
static device_attach_t ata_usbchannel_attach;
static device_detach_t ata_usbchannel_detach;

static ata_setmode_t ata_usbchannel_setmode;
static ata_locking_t ata_usbchannel_locking;

/*
 * USB frontend part
 */

struct usb2_config atausb2_config[ATAUSB_T_BBB_MAX] = {

	[ATAUSB_T_BBB_RESET1] = {
		.type = UE_CONTROL,
		.endpoint = 0x00,	/* Control pipe */
		.direction = UE_DIR_ANY,
		.mh.bufsize = sizeof(struct usb2_device_request),
		.mh.flags = {},
		.mh.callback = &atausb2_t_bbb_reset1_callback,
		.mh.timeout = 5000,	/* 5 seconds */
		.mh.interval = 500,	/* 500 milliseconds */
	},

	[ATAUSB_T_BBB_RESET2] = {
		.type = UE_CONTROL,
		.endpoint = 0x00,	/* Control pipe */
		.direction = UE_DIR_ANY,
		.mh.bufsize = sizeof(struct usb2_device_request),
		.mh.flags = {},
		.mh.callback = &atausb2_t_bbb_reset2_callback,
		.mh.timeout = 5000,	/* 5 seconds */
		.mh.interval = 50,	/* 50 milliseconds */
	},

	[ATAUSB_T_BBB_RESET3] = {
		.type = UE_CONTROL,
		.endpoint = 0x00,	/* Control pipe */
		.direction = UE_DIR_ANY,
		.mh.bufsize = sizeof(struct usb2_device_request),
		.mh.flags = {},
		.mh.callback = &atausb2_t_bbb_reset3_callback,
		.mh.timeout = 5000,	/* 5 seconds */
		.mh.interval = 50,	/* 50 milliseconds */
	},

	[ATAUSB_T_BBB_COMMAND] = {
		.type = UE_BULK,
		.endpoint = UE_ADDR_ANY,
		.direction = UE_DIR_OUT,
		.mh.bufsize = sizeof(struct bbb_cbw),
		.mh.flags = {},
		.mh.callback = &atausb2_t_bbb_command_callback,
		.mh.timeout = 5000,	/* 5 seconds */
	},

	[ATAUSB_T_BBB_DATA_READ] = {
		.type = UE_BULK,
		.endpoint = UE_ADDR_ANY,
		.direction = UE_DIR_IN,
		.mh.bufsize = ATAUSB_BULK_SIZE,
		.mh.flags = {.proxy_buffer = 1,.short_xfer_ok = 1,},
		.mh.callback = &atausb2_t_bbb_data_read_callback,
		.mh.timeout = 0,	/* overwritten later */
	},

	[ATAUSB_T_BBB_DATA_RD_CS] = {
		.type = UE_CONTROL,
		.endpoint = 0x00,	/* Control pipe */
		.direction = UE_DIR_ANY,
		.mh.bufsize = sizeof(struct usb2_device_request),
		.mh.flags = {},
		.mh.callback = &atausb2_t_bbb_data_rd_cs_callback,
		.mh.timeout = 5000,	/* 5 seconds */
	},

	[ATAUSB_T_BBB_DATA_WRITE] = {
		.type = UE_BULK,
		.endpoint = UE_ADDR_ANY,
		.direction = UE_DIR_OUT,
		.mh.bufsize = ATAUSB_BULK_SIZE,
		.mh.flags = {.proxy_buffer = 1,.short_xfer_ok = 1,},
		.mh.callback = &atausb2_t_bbb_data_write_callback,
		.mh.timeout = 0,	/* overwritten later */
	},

	[ATAUSB_T_BBB_DATA_WR_CS] = {
		.type = UE_CONTROL,
		.endpoint = 0x00,	/* Control pipe */
		.direction = UE_DIR_ANY,
		.mh.bufsize = sizeof(struct usb2_device_request),
		.mh.flags = {},
		.mh.callback = &atausb2_t_bbb_data_wr_cs_callback,
		.mh.timeout = 5000,	/* 5 seconds */
	},

	[ATAUSB_T_BBB_STATUS] = {
		.type = UE_BULK,
		.endpoint = UE_ADDR_ANY,
		.direction = UE_DIR_IN,
		.mh.bufsize = sizeof(struct bbb_csw),
		.mh.flags = {.short_xfer_ok = 1,},
		.mh.callback = &atausb2_t_bbb_status_callback,
		.mh.timeout = 5000,	/* ms */
	},
};

static devclass_t atausb2_devclass;

static device_method_t atausb2_methods[] = {
	DEVMETHOD(device_probe, atausb2_probe),
	DEVMETHOD(device_attach, atausb2_attach),
	DEVMETHOD(device_detach, atausb2_detach),
	{0, 0}
};

static driver_t atausb2_driver = {
	.name = "atausb",
	.methods = atausb2_methods,
	.size = sizeof(struct atausb2_softc),
};

DRIVER_MODULE(atausb, ushub, atausb2_driver, atausb2_devclass, 0, 0);
MODULE_DEPEND(atausb, usb, 1, 1, 1);
MODULE_VERSION(atausb, 1);

static int
atausb2_probe(device_t dev)
{
	struct usb2_attach_arg *uaa = device_get_ivars(dev);
	struct usb2_interface_descriptor *id;

	if (uaa->usb2_mode != USB_MODE_HOST) {
		return (ENXIO);
	}
	if (uaa->use_generic == 0) {
		/* give other drivers a try first */
		return (ENXIO);
	}
	id = usb2_get_interface_descriptor(uaa->iface);
	if ((!id) || (id->bInterfaceClass != UICLASS_MASS)) {
		return (ENXIO);
	}
	switch (id->bInterfaceSubClass) {
	case UISUBCLASS_QIC157:
	case UISUBCLASS_RBC:
	case UISUBCLASS_SCSI:
	case UISUBCLASS_SFF8020I:
	case UISUBCLASS_SFF8070I:
	case UISUBCLASS_UFI:
		switch (id->bInterfaceProtocol) {
		case UIPROTO_MASS_CBI:
		case UIPROTO_MASS_CBI_I:
		case UIPROTO_MASS_BBB:
		case UIPROTO_MASS_BBB_OLD:
			return (0);
		default:
			return (0);
		}
		break;
	default:
		return (0);
	}
}

static int
atausb2_attach(device_t dev)
{
	struct atausb2_softc *sc = device_get_softc(dev);
	struct usb2_attach_arg *uaa = device_get_ivars(dev);
	struct usb2_interface_descriptor *id;
	const char *proto, *subclass;
	struct usb2_device_request request;
	device_t child;
	uint16_t i;
	uint8_t maxlun;
	uint8_t has_intr;
	int err;

	device_set_usb2_desc(dev);

	sc->dev = dev;
	sc->maxlun = 0;
	sc->locked_ch = NULL;
	sc->restart_ch = NULL;
	sc->usb2_speed = usb2_get_speed(uaa->device);
	mtx_init(&sc->locked_mtx, "ATAUSB lock", NULL, (MTX_DEF | MTX_RECURSE));

	id = usb2_get_interface_descriptor(uaa->iface);
	switch (id->bInterfaceProtocol) {
	case UIPROTO_MASS_BBB:
	case UIPROTO_MASS_BBB_OLD:
		proto = "Bulk-Only";
		break;
	case UIPROTO_MASS_CBI:
		proto = "CBI";
		break;
	case UIPROTO_MASS_CBI_I:
		proto = "CBI with CCI";
		break;
	default:
		proto = "Unknown";
	}

	switch (id->bInterfaceSubClass) {
	case UISUBCLASS_RBC:
		subclass = "RBC";
		break;
	case UISUBCLASS_QIC157:
	case UISUBCLASS_SFF8020I:
	case UISUBCLASS_SFF8070I:
		subclass = "ATAPI";
		break;
	case UISUBCLASS_SCSI:
		subclass = "SCSI";
		break;
	case UISUBCLASS_UFI:
		subclass = "UFI";
		break;
	default:
		subclass = "Unknown";
	}

	has_intr = (id->bInterfaceProtocol == UIPROTO_MASS_CBI_I);
	sc->iface_no = id->bInterfaceNumber;

	device_printf(dev, "using %s over %s\n", subclass, proto);
	if (strcmp(proto, "Bulk-Only") ||
	    (strcmp(subclass, "ATAPI") && strcmp(subclass, "SCSI"))) {
		goto detach;
	}
	err = usb2_transfer_setup(uaa->device, &uaa->info.bIfaceIndex,
	    sc->xfer, atausb2_config, ATAUSB_T_BBB_MAX, sc,
	    &sc->locked_mtx);

	/* skip reset first time */
	sc->last_xfer_no = ATAUSB_T_BBB_COMMAND;

	if (err) {
		device_printf(sc->dev, "could not setup required "
		    "transfers, %s\n", usb2_errstr(err));
		goto detach;
	}
	/* get number of devices so we can add matching channels */
	request.bmRequestType = UT_READ_CLASS_INTERFACE;
	request.bRequest = 0xfe;	/* GET_MAX_LUN; */
	USETW(request.wValue, 0);
	USETW(request.wIndex, sc->iface_no);
	USETW(request.wLength, sizeof(maxlun));
	err = usb2_do_request(uaa->device, &Giant, &request, &maxlun);

	if (err) {
		if (bootverbose) {
			device_printf(sc->dev, "get maxlun not supported %s\n",
			    usb2_errstr(err));
		}
	} else {
		sc->maxlun = maxlun;
		if (bootverbose) {
			device_printf(sc->dev, "maxlun=%d\n", sc->maxlun);
		}
	}

	/* ata channels are children to this USB control device */
	for (i = 0; i <= sc->maxlun; i++) {
		if ((child = device_add_child(sc->dev, "ata",
		    devclass_find_free_unit(ata_devclass, 2))) == NULL) {
			device_printf(sc->dev, "failed to add ata child device\n");
		} else
		    device_set_ivars(child, (void *)(intptr_t)i);
	}
	bus_generic_attach(sc->dev);

	return (0);

detach:
	atausb2_detach(dev);
	return (ENXIO);
}

static int
atausb2_detach(device_t dev)
{
	struct atausb2_softc *sc = device_get_softc(dev);
	device_t *children;
	int nchildren, i;

	/* teardown our statemachine */

	usb2_transfer_unsetup(sc->xfer, ATAUSB_T_MAX);

	/* detach & delete all children, if any */

	if (!device_get_children(dev, &children, &nchildren)) {
		for (i = 0; i < nchildren; i++) {
			device_delete_child(dev, children[i]);
		}
		free(children, M_TEMP);
	}
	mtx_destroy(&sc->locked_mtx);
	return (0);
}

static void
atausb2_transfer_start(struct atausb2_softc *sc, uint8_t xfer_no)
{
	if (atausbdebug) {
		device_printf(sc->dev, "BBB transfer %d\n", xfer_no);
	}
	if (sc->xfer[xfer_no]) {
		sc->last_xfer_no = xfer_no;
		usb2_transfer_start(sc->xfer[xfer_no]);
	} else {
		atausb2_cancel_request(sc);
	}
}

static void
atausb2_t_bbb_reset1_callback(struct usb2_xfer *xfer)
{
	struct atausb2_softc *sc = xfer->priv_sc;
	struct usb2_device_request req;

	switch (USB_GET_STATE(xfer)) {
	case USB_ST_TRANSFERRED:
		atausb2_transfer_start(sc, ATAUSB_T_BBB_RESET2);
		return;

	case USB_ST_SETUP:
		req.bmRequestType = UT_WRITE_CLASS_INTERFACE;
		req.bRequest = 0xff;	/* bulk-only reset */
		USETW(req.wValue, 0);
		req.wIndex[0] = sc->iface_no;
		req.wIndex[1] = 0;
		USETW(req.wLength, 0);

		usb2_copy_in(xfer->frbuffers, 0, &req, sizeof(req));

		xfer->frlengths[0] = sizeof(req);
		xfer->nframes = 1;
		usb2_start_hardware(xfer);
		return;

	default:			/* Error */
		atausb2_tr_error(xfer);
		return;

	}
}

static void
atausb2_t_bbb_reset2_callback(struct usb2_xfer *xfer)
{
	atausb2_t_bbb_data_clear_stall_callback(xfer, ATAUSB_T_BBB_RESET3,
	    ATAUSB_T_BBB_DATA_READ);
}

static void
atausb2_t_bbb_reset3_callback(struct usb2_xfer *xfer)
{
	atausb2_t_bbb_data_clear_stall_callback(xfer, ATAUSB_T_BBB_COMMAND,
	    ATAUSB_T_BBB_DATA_WRITE);
}

static void
atausb2_t_bbb_data_clear_stall_callback(struct usb2_xfer *xfer,
    uint8_t next_xfer,
    uint8_t stall_xfer)
{
	struct atausb2_softc *sc = xfer->priv_sc;

	switch (USB_GET_STATE(xfer)) {
	case USB_ST_TRANSFERRED:
tr_transferred:
		atausb2_transfer_start(sc, next_xfer);
		return;

	case USB_ST_SETUP:
		if (usb2_clear_stall_callback(xfer, sc->xfer[stall_xfer])) {
			goto tr_transferred;
		}
		return;

	default:			/* Error */
		atausb2_tr_error(xfer);
		return;

	}
}

static void
atausb2_t_bbb_command_callback(struct usb2_xfer *xfer)
{
	struct atausb2_softc *sc = xfer->priv_sc;
	struct ata_request *request = sc->ata_request;
	struct ata_channel *ch;
	uint32_t tag;

	switch (USB_GET_STATE(xfer)) {
	case USB_ST_TRANSFERRED:
		atausb2_transfer_start
		    (sc, ((request->flags & ATA_R_READ) ? ATAUSB_T_BBB_DATA_READ :
		    (request->flags & ATA_R_WRITE) ? ATAUSB_T_BBB_DATA_WRITE :
		    ATAUSB_T_BBB_STATUS));
		return;

	case USB_ST_SETUP:

		sc->status_try = 0;

		if (request) {
			ch = device_get_softc(request->parent);

			sc->timeout = (request->timeout * 1000) + 5000;

			tag = UGETDW(sc->cbw.tag) + 1;

			USETDW(sc->cbw.signature, CBWSIGNATURE);
			USETDW(sc->cbw.tag, tag);
			USETDW(sc->cbw.transfer_length, request->bytecount);
			sc->cbw.flags = (request->flags & ATA_R_READ) ? CBWFLAGS_IN : CBWFLAGS_OUT;
			sc->cbw.lun = ch->unit;
			sc->cbw.length = 16;
			bzero(sc->cbw.cdb, 16);
			bcopy(request->u.atapi.ccb, sc->cbw.cdb, 12);	/* XXX SOS */

			usb2_copy_in(xfer->frbuffers, 0, &sc->cbw, sizeof(sc->cbw));

			xfer->frlengths[0] = sizeof(sc->cbw);
			usb2_start_hardware(xfer);
		}
		return;

	default:			/* Error */
		atausb2_tr_error(xfer);
		return;

	}
}

static void
atausb2_t_bbb_data_read_callback(struct usb2_xfer *xfer)
{
	struct atausb2_softc *sc = xfer->priv_sc;
	uint32_t max_bulk = xfer->max_data_length;

	switch (USB_GET_STATE(xfer)) {
	case USB_ST_TRANSFERRED:

		usb2_copy_out(xfer->frbuffers, 0,
		    sc->ata_data, xfer->actlen);

		sc->ata_bytecount -= xfer->actlen;
		sc->ata_data += xfer->actlen;
		sc->ata_donecount += xfer->actlen;

		if (xfer->actlen < xfer->sumlen) {
			/* short transfer */
			sc->ata_bytecount = 0;
		}
	case USB_ST_SETUP:

		if (atausbdebug > 1) {
			device_printf(sc->dev, "%s: max_bulk=%d, ata_bytecount=%d\n",
			    __FUNCTION__, max_bulk, sc->ata_bytecount);
		}
		if (sc->ata_bytecount == 0) {
			atausb2_transfer_start(sc, ATAUSB_T_BBB_STATUS);
			return;
		}
		if (max_bulk > sc->ata_bytecount) {
			max_bulk = sc->ata_bytecount;
		}
		xfer->timeout = sc->timeout;
		xfer->frlengths[0] = max_bulk;

		usb2_start_hardware(xfer);
		return;

	default:			/* Error */
		if (xfer->error == USB_ERR_CANCELLED) {
			atausb2_tr_error(xfer);
		} else {
			atausb2_transfer_start(sc, ATAUSB_T_BBB_DATA_RD_CS);
		}
		return;

	}
}

static void
atausb2_t_bbb_data_rd_cs_callback(struct usb2_xfer *xfer)
{
	atausb2_t_bbb_data_clear_stall_callback(xfer, ATAUSB_T_BBB_STATUS,
	    ATAUSB_T_BBB_DATA_READ);
}

static void
atausb2_t_bbb_data_write_callback(struct usb2_xfer *xfer)
{
	struct atausb2_softc *sc = xfer->priv_sc;
	uint32_t max_bulk = xfer->max_data_length;

	switch (USB_GET_STATE(xfer)) {
	case USB_ST_TRANSFERRED:

		sc->ata_bytecount -= xfer->actlen;
		sc->ata_data += xfer->actlen;
		sc->ata_donecount += xfer->actlen;

	case USB_ST_SETUP:

		if (atausbdebug > 1) {
			device_printf(sc->dev, "%s: max_bulk=%d, ata_bytecount=%d\n",
			    __FUNCTION__, max_bulk, sc->ata_bytecount);
		}
		if (sc->ata_bytecount == 0) {
			atausb2_transfer_start(sc, ATAUSB_T_BBB_STATUS);
			return;
		}
		if (max_bulk > sc->ata_bytecount) {
			max_bulk = sc->ata_bytecount;
		}
		xfer->timeout = sc->timeout;
		xfer->frlengths[0] = max_bulk;

		usb2_copy_in(xfer->frbuffers, 0,
		    sc->ata_data, max_bulk);

		usb2_start_hardware(xfer);
		return;

	default:			/* Error */
		if (xfer->error == USB_ERR_CANCELLED) {
			atausb2_tr_error(xfer);
		} else {
			atausb2_transfer_start(sc, ATAUSB_T_BBB_DATA_WR_CS);
		}
		return;

	}
}

static void
atausb2_t_bbb_data_wr_cs_callback(struct usb2_xfer *xfer)
{
	atausb2_t_bbb_data_clear_stall_callback(xfer, ATAUSB_T_BBB_STATUS,
	    ATAUSB_T_BBB_DATA_WRITE);
}

static void
atausb2_t_bbb_status_callback(struct usb2_xfer *xfer)
{
	struct atausb2_softc *sc = xfer->priv_sc;
	struct ata_request *request = sc->ata_request;
	uint32_t residue;

	switch (USB_GET_STATE(xfer)) {
	case USB_ST_TRANSFERRED:

		if (xfer->actlen < sizeof(sc->csw)) {
			bzero(&sc->csw, sizeof(sc->csw));
		}
		usb2_copy_out(xfer->frbuffers, 0, &sc->csw, xfer->actlen);

		if (request->flags & (ATA_R_READ | ATA_R_WRITE)) {
			request->donecount = sc->ata_donecount;
		}
		residue = UGETDW(sc->csw.residue);

		if (!residue) {
			residue = (request->bytecount - request->donecount);
		}
		if (residue > request->bytecount) {
			if (atausbdebug) {
				device_printf(sc->dev, "truncating residue from %d "
				    "to %d bytes\n", residue,
				    request->bytecount);
			}
			residue = request->bytecount;
		}
		/* check CSW and handle eventual error */
		if (UGETDW(sc->csw.signature) != CSWSIGNATURE) {
			if (atausbdebug) {
				device_printf(sc->dev, "bad CSW signature 0x%08x != 0x%08x\n",
				    UGETDW(sc->csw.signature), CSWSIGNATURE);
			}
			goto tr_error;
		} else if (UGETDW(sc->csw.tag) != UGETDW(sc->cbw.tag)) {
			if (atausbdebug) {
				device_printf(sc->dev, "bad CSW tag %d != %d\n",
				    UGETDW(sc->csw.tag), UGETDW(sc->cbw.tag));
			}
			goto tr_error;
		} else if (sc->csw.status > CSWSTATUS_PHASE) {
			if (atausbdebug) {
				device_printf(sc->dev, "bad CSW status %d > %d\n",
				    sc->csw.status, CSWSTATUS_PHASE);
			}
			goto tr_error;
		} else if (sc->csw.status == CSWSTATUS_PHASE) {
			if (atausbdebug) {
				device_printf(sc->dev, "phase error residue = %d\n", residue);
			}
			goto tr_error;
		} else if (request->donecount > request->bytecount) {
			if (atausbdebug) {
				device_printf(sc->dev, "buffer overrun %d > %d\n",
				    request->donecount, request->bytecount);
			}
			goto tr_error;
		} else if (sc->csw.status == CSWSTATUS_FAILED) {
			if (atausbdebug) {
				device_printf(sc->dev, "CSWSTATUS_FAILED\n");
			}
			request->error = ATA_E_ATAPI_SENSE_MASK;
		}
		sc->last_xfer_no = ATAUSB_T_BBB_COMMAND;

		sc->ata_request = NULL;

		/* drop the USB transfer lock while doing the ATA interrupt */
		mtx_unlock(&sc->locked_mtx);

		ata_interrupt(device_get_softc(request->parent));

		mtx_lock(&sc->locked_mtx);
		return;

	case USB_ST_SETUP:
		xfer->frlengths[0] = xfer->max_data_length;
		usb2_start_hardware(xfer);
		return;

	default:
tr_error:
		if ((xfer->error == USB_ERR_CANCELLED) ||
		    (sc->status_try)) {
			atausb2_tr_error(xfer);
		} else {
			sc->status_try = 1;
			atausb2_transfer_start(sc, ATAUSB_T_BBB_DATA_RD_CS);
		}
		return;

	}
}

static void
atausb2_cancel_request(struct atausb2_softc *sc)
{
	struct ata_request *request;

	mtx_assert(&sc->locked_mtx, MA_OWNED);

	request = sc->ata_request;
	sc->ata_request = NULL;
	sc->last_xfer_no = ATAUSB_T_BBB_RESET1;

	if (request) {
		request->error = ATA_E_ATAPI_SENSE_MASK;

		mtx_unlock(&sc->locked_mtx);

		ata_interrupt(device_get_softc(request->parent));

		mtx_lock(&sc->locked_mtx);
	}
}

static void
atausb2_tr_error(struct usb2_xfer *xfer)
{
	struct atausb2_softc *sc = xfer->priv_sc;

	if (xfer->error != USB_ERR_CANCELLED) {

		if (atausbdebug) {
			device_printf(sc->dev, "transfer failed, %s, in state %d "
			    "-> BULK reset\n", usb2_errstr(xfer->error),
			    sc->last_xfer_no);
		}
	}
	atausb2_cancel_request(sc);
}

/*
 * ATA backend part
 */
struct atapi_inquiry {
	uint8_t	device_type;
	uint8_t	device_modifier;
	uint8_t	version;
	uint8_t	response_format;
	uint8_t	length;
	uint8_t	reserved[2];
	uint8_t	flags;
	uint8_t	vendor[8];
	uint8_t	product[16];
	uint8_t	revision[4];
	/* uint8_t    crap[60]; */
} __packed;

static int
ata_usbchannel_begin_transaction(struct ata_request *request)
{
	struct atausb2_softc *sc =
	device_get_softc(device_get_parent(request->parent));
	int error;

	if (atausbdebug > 1) {
		device_printf(request->dev, "begin_transaction %s\n",
		    ata_cmd2str(request));
	}
	mtx_lock(&sc->locked_mtx);

	/* sanity, just in case */
	if (sc->ata_request) {
		device_printf(request->dev, "begin is busy, "
		    "state = %d\n", sc->last_xfer_no);
		request->result = EBUSY;
		error = ATA_OP_FINISHED;
		goto done;
	}
	/*
	 * XXX SOS convert the request into the format used, only BBB for
	 * now
	 */

	/* ATA/ATAPI IDENTIFY needs special treatment */
	if (!(request->flags & ATA_R_ATAPI)) {
		if (request->u.ata.command != ATA_ATAPI_IDENTIFY) {
			device_printf(request->dev, "%s unsupported\n",
			    ata_cmd2str(request));
			request->result = EIO;
			error = ATA_OP_FINISHED;
			goto done;
		}
		request->flags |= ATA_R_ATAPI;
		bzero(request->u.atapi.ccb, 16);
		request->u.atapi.ccb[0] = ATAPI_INQUIRY;
		request->u.atapi.ccb[4] = 255;	/* sizeof(struct
						 * atapi_inquiry); */
		request->data += 256;	/* arbitrary offset into ata_param */
		request->bytecount = 255;	/* sizeof(struct
						 * atapi_inquiry); */
	}
	if (sc->xfer[sc->last_xfer_no]) {

		sc->ata_request = request;
		sc->ata_bytecount = request->bytecount;
		sc->ata_data = request->data;
		sc->ata_donecount = 0;

		usb2_transfer_start(sc->xfer[sc->last_xfer_no]);
		error = ATA_OP_CONTINUES;
	} else {
		request->result = EIO;
		error = ATA_OP_FINISHED;
	}

done:
	mtx_unlock(&sc->locked_mtx);
	return (error);
}

static int
ata_usbchannel_end_transaction(struct ata_request *request)
{
	if (atausbdebug > 1) {
		device_printf(request->dev, "end_transaction %s\n",
		    ata_cmd2str(request));
	}
	/*
	 * XXX SOS convert the request from the format used, only BBB for
	 * now
	 */

	/* ATA/ATAPI IDENTIFY needs special treatment */
	if ((request->flags & ATA_R_ATAPI) &&
	    (request->u.atapi.ccb[0] == ATAPI_INQUIRY)) {
		struct ata_device *atadev = device_get_softc(request->dev);
		struct atapi_inquiry *inquiry = (struct atapi_inquiry *)request->data;
		uint16_t *ptr;

		/* convert inquiry data into simple ata_param like format */
		atadev->param.config = ATA_PROTO_ATAPI | ATA_PROTO_ATAPI_12;
		atadev->param.config |= (inquiry->device_type & 0x1f) << 8;
		bzero(atadev->param.model, sizeof(atadev->param.model));
		strncpy(atadev->param.model, inquiry->vendor, 8);
		strcpy(atadev->param.model, "  ");
		strncpy(atadev->param.model, inquiry->product, 16);
		ptr = (uint16_t *)(atadev->param.model + sizeof(atadev->param.model));
		while (--ptr >= (uint16_t *)atadev->param.model) {
			*ptr = ntohs(*ptr);
		}
		strncpy(atadev->param.revision, inquiry->revision, 4);
		ptr = (uint16_t *)(atadev->param.revision + sizeof(atadev->param.revision));
		while (--ptr >= (uint16_t *)atadev->param.revision) {
			*ptr = ntohs(*ptr);
		}
		request->result = 0;
	}
	return (ATA_OP_FINISHED);
}

static int
ata_usbchannel_probe(device_t dev)
{
	char buffer[32];

	snprintf(buffer, sizeof(buffer), "USB lun %d",
	    (int)(intptr_t)device_get_ivars(dev));
	device_set_desc_copy(dev, buffer);

	return (0);
}

static int
ata_usbchannel_attach(device_t dev)
{
	struct ata_channel *ch = device_get_softc(dev);

	if (ch->attached)
		return (0);
	ch->attached = 1;

	/* initialize the softc basics */
	ch->dev = dev;
	ch->unit = (intptr_t)device_get_ivars(dev);
	ch->state = ATA_IDLE;
	ch->hw.begin_transaction = ata_usbchannel_begin_transaction;
	ch->hw.end_transaction = ata_usbchannel_end_transaction;
	ch->hw.status = NULL;
	ch->hw.command = NULL;
	bzero(&ch->state_mtx, sizeof(struct mtx));
	mtx_init(&ch->state_mtx, "ATA state lock", NULL, MTX_DEF);
	bzero(&ch->queue_mtx, sizeof(struct mtx));
	mtx_init(&ch->queue_mtx, "ATA queue lock", NULL, MTX_DEF);
	TAILQ_INIT(&ch->ata_queue);

	/* XXX SOS reset the controller HW, the channel and device(s) */
	/* ATA_RESET(dev); */

	/* probe and attach device on this channel */
	ch->devices = ATA_ATAPI_MASTER;
	if (!ata_delayed_attach) {
		ata_identify(dev);
	}
	return (0);
}

static int
ata_usbchannel_detach(device_t dev)
{
	struct ata_channel *ch = device_get_softc(dev);
	device_t *children;
	int nchildren, i;

	if (!ch->attached)
		return (0);
	ch->attached = 0;

	/* detach & delete all children */
	if (!device_get_children(dev, &children, &nchildren)) {
		for (i = 0; i < nchildren; i++)
			if (children[i])
				device_delete_child(dev, children[i]);
		free(children, M_TEMP);
	}
	mtx_destroy(&ch->state_mtx);
	mtx_destroy(&ch->queue_mtx);
	return (0);
}

static void
ata_usbchannel_setmode(device_t parent, device_t dev)
{
	struct atausb2_softc *sc = device_get_softc(GRANDPARENT(dev));
	struct ata_device *atadev = device_get_softc(dev);

	if (sc->usb2_speed == USB_SPEED_HIGH)
		atadev->mode = ATA_USB2;
	else
		atadev->mode = ATA_USB1;
}

static int
ata_usbchannel_locking(device_t dev, int flags)
{
	struct atausb2_softc *sc = device_get_softc(device_get_parent(dev));
	struct ata_channel *ch = device_get_softc(dev);
	int res = -1;

	mtx_lock(&sc->locked_mtx);
	switch (flags) {
	case ATA_LF_LOCK:
		if (sc->locked_ch == NULL)
			sc->locked_ch = ch;
		if (sc->locked_ch != ch)
			sc->restart_ch = ch;
		break;

	case ATA_LF_UNLOCK:
		if (sc->locked_ch == ch) {
			sc->locked_ch = NULL;
			if (sc->restart_ch) {
				ch = sc->restart_ch;
				sc->restart_ch = NULL;
				mtx_unlock(&sc->locked_mtx);
				ata_start(ch->dev);
				return (res);
			}
		}
		break;

	case ATA_LF_WHICH:
		break;
	}
	if (sc->locked_ch) {
		res = sc->locked_ch->unit;
	}
	mtx_unlock(&sc->locked_mtx);
	return (res);
}

static device_method_t ata_usbchannel_methods[] = {
	/* device interface */
	DEVMETHOD(device_probe, ata_usbchannel_probe),
	DEVMETHOD(device_attach, ata_usbchannel_attach),
	DEVMETHOD(device_detach, ata_usbchannel_detach),

	/* ATA methods */
	DEVMETHOD(ata_setmode, ata_usbchannel_setmode),
	DEVMETHOD(ata_locking, ata_usbchannel_locking),
	/* DEVMETHOD(ata_reset,            ata_usbchannel_reset), */

	{0, 0}
};

static driver_t ata_usbchannel_driver = {
	"ata",
	ata_usbchannel_methods,
	sizeof(struct ata_channel),
};

DRIVER_MODULE(ata, atausb, ata_usbchannel_driver, ata_devclass, 0, 0);
MODULE_DEPEND(atausb, ata, 1, 1, 1);