Moved, renamed, and deleted files

The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.

1 files changed, 862 insertions, 0 deletions

diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
new file mode 100644
index 00000000..8ec8a6e6
--- /dev/null
+++ b/drivers/usb/storage/uas.c
@@ -0,0 +1,862 @@
+/*
+ * USB Attached SCSI
+ * Note that this is not the same as the USB Mass Storage driver
+ *
+ * Copyright Matthew Wilcox for Intel Corp, 2010
+ * Copyright Sarah Sharp for Intel Corp, 2010
+ *
+ * Distributed under the terms of the GNU GPL, version two.
+ */
+
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/usb/hcd.h>
+#include <linux/usb/storage.h>
+#include <linux/usb/uas.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_dbg.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_tcq.h>
+
+/*
+ * The r00-r01c specs define this version of the SENSE IU data structure.
+ * It's still in use by several different firmware releases.
+ */
+struct sense_iu_old {
+	__u8 iu_id;
+	__u8 rsvd1;
+	__be16 tag;
+	__be16 len;
+	__u8 status;
+	__u8 service_response;
+	__u8 sense[SCSI_SENSE_BUFFERSIZE];
+};
+
+struct uas_dev_info {
+	struct usb_interface *intf;
+	struct usb_device *udev;
+	int qdepth;
+	unsigned cmd_pipe, status_pipe, data_in_pipe, data_out_pipe;
+	unsigned use_streams:1;
+	unsigned uas_sense_old:1;
+	struct scsi_cmnd *cmnd;
+	struct urb *status_urb; /* used only if stream support is available */
+};
+
+enum {
+	ALLOC_STATUS_URB	= (1 << 0),
+	SUBMIT_STATUS_URB	= (1 << 1),
+	ALLOC_DATA_IN_URB	= (1 << 2),
+	SUBMIT_DATA_IN_URB	= (1 << 3),
+	ALLOC_DATA_OUT_URB	= (1 << 4),
+	SUBMIT_DATA_OUT_URB	= (1 << 5),
+	ALLOC_CMD_URB		= (1 << 6),
+	SUBMIT_CMD_URB		= (1 << 7),
+	COMPLETED_DATA_IN	= (1 << 8),
+	COMPLETED_DATA_OUT	= (1 << 9),
+	DATA_COMPLETES_CMD	= (1 << 10),
+};
+
+/* Overrides scsi_pointer */
+struct uas_cmd_info {
+	unsigned int state;
+	unsigned int stream;
+	struct urb *cmd_urb;
+	/* status_urb is used only if stream support isn't available */
+	struct urb *status_urb;
+	struct urb *data_in_urb;
+	struct urb *data_out_urb;
+	struct list_head list;
+};
+
+/* I hate forward declarations, but I actually have a loop */
+static int uas_submit_urbs(struct scsi_cmnd *cmnd,
+				struct uas_dev_info *devinfo, gfp_t gfp);
+static void uas_do_work(struct work_struct *work);
+
+static DECLARE_WORK(uas_work, uas_do_work);
+static DEFINE_SPINLOCK(uas_work_lock);
+static LIST_HEAD(uas_work_list);
+
+static void uas_do_work(struct work_struct *work)
+{
+	struct uas_cmd_info *cmdinfo;
+	struct uas_cmd_info *temp;
+	struct list_head list;
+	int err;
+
+	spin_lock_irq(&uas_work_lock);
+	list_replace_init(&uas_work_list, &list);
+	spin_unlock_irq(&uas_work_lock);
+
+	list_for_each_entry_safe(cmdinfo, temp, &list, list) {
+		struct scsi_pointer *scp = (void *)cmdinfo;
+		struct scsi_cmnd *cmnd = container_of(scp,
+							struct scsi_cmnd, SCp);
+		err = uas_submit_urbs(cmnd, cmnd->device->hostdata, GFP_NOIO);
+		if (err) {
+			list_del(&cmdinfo->list);
+			spin_lock_irq(&uas_work_lock);
+			list_add_tail(&cmdinfo->list, &uas_work_list);
+			spin_unlock_irq(&uas_work_lock);
+			schedule_work(&uas_work);
+		}
+	}
+}
+
+static void uas_sense(struct urb *urb, struct scsi_cmnd *cmnd)
+{
+	struct sense_iu *sense_iu = urb->transfer_buffer;
+	struct scsi_device *sdev = cmnd->device;
+	struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
+
+	if (urb->actual_length > 16) {
+		unsigned len = be16_to_cpup(&sense_iu->len);
+		if (len + 16 != urb->actual_length) {
+			int newlen = min(len + 16, urb->actual_length) - 16;
+			if (newlen < 0)
+				newlen = 0;
+			sdev_printk(KERN_INFO, sdev, "%s: urb length %d "
+				"disagrees with IU sense data length %d, "
+				"using %d bytes of sense data\n", __func__,
+					urb->actual_length, len, newlen);
+			len = newlen;
+		}
+		memcpy(cmnd->sense_buffer, sense_iu->sense, len);
+	}
+
+	cmnd->result = sense_iu->status;
+	if (!(cmdinfo->state & DATA_COMPLETES_CMD))
+		cmnd->scsi_done(cmnd);
+}
+
+static void uas_sense_old(struct urb *urb, struct scsi_cmnd *cmnd)
+{
+	struct sense_iu_old *sense_iu = urb->transfer_buffer;
+	struct scsi_device *sdev = cmnd->device;
+	struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
+
+	if (urb->actual_length > 8) {
+		unsigned len = be16_to_cpup(&sense_iu->len) - 2;
+		if (len + 8 != urb->actual_length) {
+			int newlen = min(len + 8, urb->actual_length) - 8;
+			if (newlen < 0)
+				newlen = 0;
+			sdev_printk(KERN_INFO, sdev, "%s: urb length %d "
+				"disagrees with IU sense data length %d, "
+				"using %d bytes of sense data\n", __func__,
+					urb->actual_length, len, newlen);
+			len = newlen;
+		}
+		memcpy(cmnd->sense_buffer, sense_iu->sense, len);
+	}
+
+	cmnd->result = sense_iu->status;
+	if (!(cmdinfo->state & DATA_COMPLETES_CMD))
+		cmnd->scsi_done(cmnd);
+}
+
+static void uas_xfer_data(struct urb *urb, struct scsi_cmnd *cmnd,
+							unsigned direction)
+{
+	struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
+	int err;
+
+	cmdinfo->state = direction;
+	err = uas_submit_urbs(cmnd, cmnd->device->hostdata, GFP_ATOMIC);
+	if (err) {
+		spin_lock(&uas_work_lock);
+		list_add_tail(&cmdinfo->list, &uas_work_list);
+		spin_unlock(&uas_work_lock);
+		schedule_work(&uas_work);
+	}
+}
+
+static void uas_stat_cmplt(struct urb *urb)
+{
+	struct iu *iu = urb->transfer_buffer;
+	struct Scsi_Host *shost = urb->context;
+	struct uas_dev_info *devinfo = (void *)shost->hostdata[0];
+	struct scsi_cmnd *cmnd;
+	struct uas_cmd_info *cmdinfo;
+	u16 tag;
+	int ret;
+
+	if (urb->status) {
+		dev_err(&urb->dev->dev, "URB BAD STATUS %d\n", urb->status);
+		if (devinfo->use_streams)
+			usb_free_urb(urb);
+		return;
+	}
+
+	tag = be16_to_cpup(&iu->tag) - 1;
+	if (tag == 0)
+		cmnd = devinfo->cmnd;
+	else
+		cmnd = scsi_host_find_tag(shost, tag - 1);
+	if (!cmnd) {
+		if (devinfo->use_streams) {
+			usb_free_urb(urb);
+			return;
+		}
+		ret = usb_submit_urb(urb, GFP_ATOMIC);
+		if (ret)
+			dev_err(&urb->dev->dev, "failed submit status urb\n");
+		return;
+	}
+	cmdinfo = (void *)&cmnd->SCp;
+
+	switch (iu->iu_id) {
+	case IU_ID_STATUS:
+		if (devinfo->cmnd == cmnd)
+			devinfo->cmnd = NULL;
+
+		if (!(cmdinfo->state & COMPLETED_DATA_IN) &&
+				cmdinfo->data_in_urb) {
+		       if (devinfo->use_streams) {
+			       cmdinfo->state |= DATA_COMPLETES_CMD;
+			       usb_unlink_urb(cmdinfo->data_in_urb);
+		       } else {
+			       usb_free_urb(cmdinfo->data_in_urb);
+		       }
+		}
+		if (!(cmdinfo->state & COMPLETED_DATA_OUT) &&
+				cmdinfo->data_out_urb) {
+			if (devinfo->use_streams) {
+				cmdinfo->state |= DATA_COMPLETES_CMD;
+				usb_unlink_urb(cmdinfo->data_in_urb);
+			} else {
+				usb_free_urb(cmdinfo->data_out_urb);
+			}
+		}
+
+		if (urb->actual_length < 16)
+			devinfo->uas_sense_old = 1;
+		if (devinfo->uas_sense_old)
+			uas_sense_old(urb, cmnd);
+		else
+			uas_sense(urb, cmnd);
+		break;
+	case IU_ID_READ_READY:
+		uas_xfer_data(urb, cmnd, SUBMIT_DATA_IN_URB);
+		break;
+	case IU_ID_WRITE_READY:
+		uas_xfer_data(urb, cmnd, SUBMIT_DATA_OUT_URB);
+		break;
+	default:
+		scmd_printk(KERN_ERR, cmnd,
+			"Bogus IU (%d) received on status pipe\n", iu->iu_id);
+	}
+
+	if (devinfo->use_streams) {
+		usb_free_urb(urb);
+		return;
+	}
+
+	ret = usb_submit_urb(urb, GFP_ATOMIC);
+	if (ret)
+		dev_err(&urb->dev->dev, "failed submit status urb\n");
+}
+
+static void uas_data_out_cmplt(struct urb *urb)
+{
+	struct scsi_cmnd *cmnd = urb->context;
+	struct scsi_data_buffer *sdb = scsi_out(cmnd);
+	struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
+
+	cmdinfo->state |= COMPLETED_DATA_OUT;
+
+	sdb->resid = sdb->length - urb->actual_length;
+	usb_free_urb(urb);
+
+	if (cmdinfo->state & DATA_COMPLETES_CMD)
+		cmnd->scsi_done(cmnd);
+}
+
+static void uas_data_in_cmplt(struct urb *urb)
+{
+	struct scsi_cmnd *cmnd = urb->context;
+	struct scsi_data_buffer *sdb = scsi_in(cmnd);
+	struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
+
+	cmdinfo->state |= COMPLETED_DATA_IN;
+
+	sdb->resid = sdb->length - urb->actual_length;
+	usb_free_urb(urb);
+
+	if (cmdinfo->state & DATA_COMPLETES_CMD)
+		cmnd->scsi_done(cmnd);
+}
+
+static struct urb *uas_alloc_data_urb(struct uas_dev_info *devinfo, gfp_t gfp,
+		unsigned int pipe, struct scsi_cmnd *cmnd,
+		enum dma_data_direction dir)
+{
+	struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
+	struct usb_device *udev = devinfo->udev;
+	struct urb *urb = usb_alloc_urb(0, gfp);
+	struct scsi_data_buffer *sdb;
+	usb_complete_t complete_fn;
+	u16 stream_id = cmdinfo->stream;
+
+	if (!urb)
+		goto out;
+	if (dir == DMA_FROM_DEVICE) {
+		sdb = scsi_in(cmnd);
+		complete_fn = uas_data_in_cmplt;
+	} else {
+		sdb = scsi_out(cmnd);
+		complete_fn = uas_data_out_cmplt;
+	}
+	usb_fill_bulk_urb(urb, udev, pipe, NULL, sdb->length,
+			complete_fn, cmnd);
+	urb->stream_id = stream_id;
+	urb->num_sgs = udev->bus->sg_tablesize ? sdb->table.nents : 0;
+	urb->sg = sdb->table.sgl;
+ out:
+	return urb;
+}
+
+static struct urb *uas_alloc_sense_urb(struct uas_dev_info *devinfo, gfp_t gfp,
+		struct Scsi_Host *shost, u16 stream_id)
+{
+	struct usb_device *udev = devinfo->udev;
+	struct urb *urb = usb_alloc_urb(0, gfp);
+	struct sense_iu *iu;
+
+	if (!urb)
+		goto out;
+
+	iu = kzalloc(sizeof(*iu), gfp);
+	if (!iu)
+		goto free;
+
+	usb_fill_bulk_urb(urb, udev, devinfo->status_pipe, iu, sizeof(*iu),
+						uas_stat_cmplt, shost);
+	urb->stream_id = stream_id;
+	urb->transfer_flags |= URB_FREE_BUFFER;
+ out:
+	return urb;
+ free:
+	usb_free_urb(urb);
+	return NULL;
+}
+
+static struct urb *uas_alloc_cmd_urb(struct uas_dev_info *devinfo, gfp_t gfp,
+					struct scsi_cmnd *cmnd, u16 stream_id)
+{
+	struct usb_device *udev = devinfo->udev;
+	struct scsi_device *sdev = cmnd->device;
+	struct urb *urb = usb_alloc_urb(0, gfp);
+	struct command_iu *iu;
+	int len;
+
+	if (!urb)
+		goto out;
+
+	len = cmnd->cmd_len - 16;
+	if (len < 0)
+		len = 0;
+	len = ALIGN(len, 4);
+	iu = kzalloc(sizeof(*iu) + len, gfp);
+	if (!iu)
+		goto free;
+
+	iu->iu_id = IU_ID_COMMAND;
+	if (blk_rq_tagged(cmnd->request))
+		iu->tag = cpu_to_be16(cmnd->request->tag + 2);
+	else
+		iu->tag = cpu_to_be16(1);
+	iu->prio_attr = UAS_SIMPLE_TAG;
+	iu->len = len;
+	int_to_scsilun(sdev->lun, &iu->lun);
+	memcpy(iu->cdb, cmnd->cmnd, cmnd->cmd_len);
+
+	usb_fill_bulk_urb(urb, udev, devinfo->cmd_pipe, iu, sizeof(*iu) + len,
+							usb_free_urb, NULL);
+	urb->transfer_flags |= URB_FREE_BUFFER;
+ out:
+	return urb;
+ free:
+	usb_free_urb(urb);
+	return NULL;
+}
+
+/*
+ * Why should I request the Status IU before sending the Command IU?  Spec
+ * says to, but also says the device may receive them in any order.  Seems
+ * daft to me.
+ */
+
+static int uas_submit_urbs(struct scsi_cmnd *cmnd,
+					struct uas_dev_info *devinfo, gfp_t gfp)
+{
+	struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
+
+	if (cmdinfo->state & ALLOC_STATUS_URB) {
+		cmdinfo->status_urb = uas_alloc_sense_urb(devinfo, gfp,
+				cmnd->device->host, cmdinfo->stream);
+		if (!cmdinfo->status_urb)
+			return SCSI_MLQUEUE_DEVICE_BUSY;
+		cmdinfo->state &= ~ALLOC_STATUS_URB;
+	}
+
+	if (cmdinfo->state & SUBMIT_STATUS_URB) {
+		if (usb_submit_urb(cmdinfo->status_urb, gfp)) {
+			scmd_printk(KERN_INFO, cmnd,
+					"sense urb submission failure\n");
+			return SCSI_MLQUEUE_DEVICE_BUSY;
+		}
+		cmdinfo->state &= ~SUBMIT_STATUS_URB;
+	}
+
+	if (cmdinfo->state & ALLOC_DATA_IN_URB) {
+		cmdinfo->data_in_urb = uas_alloc_data_urb(devinfo, gfp,
+					devinfo->data_in_pipe, cmnd,
+					DMA_FROM_DEVICE);
+		if (!cmdinfo->data_in_urb)
+			return SCSI_MLQUEUE_DEVICE_BUSY;
+		cmdinfo->state &= ~ALLOC_DATA_IN_URB;
+	}
+
+	if (cmdinfo->state & SUBMIT_DATA_IN_URB) {
+		if (usb_submit_urb(cmdinfo->data_in_urb, gfp)) {
+			scmd_printk(KERN_INFO, cmnd,
+					"data in urb submission failure\n");
+			return SCSI_MLQUEUE_DEVICE_BUSY;
+		}
+		cmdinfo->state &= ~SUBMIT_DATA_IN_URB;
+	}
+
+	if (cmdinfo->state & ALLOC_DATA_OUT_URB) {
+		cmdinfo->data_out_urb = uas_alloc_data_urb(devinfo, gfp,
+					devinfo->data_out_pipe, cmnd,
+					DMA_TO_DEVICE);
+		if (!cmdinfo->data_out_urb)
+			return SCSI_MLQUEUE_DEVICE_BUSY;
+		cmdinfo->state &= ~ALLOC_DATA_OUT_URB;
+	}
+
+	if (cmdinfo->state & SUBMIT_DATA_OUT_URB) {
+		if (usb_submit_urb(cmdinfo->data_out_urb, gfp)) {
+			scmd_printk(KERN_INFO, cmnd,
+					"data out urb submission failure\n");
+			return SCSI_MLQUEUE_DEVICE_BUSY;
+		}
+		cmdinfo->state &= ~SUBMIT_DATA_OUT_URB;
+	}
+
+	if (cmdinfo->state & ALLOC_CMD_URB) {
+		cmdinfo->cmd_urb = uas_alloc_cmd_urb(devinfo, gfp, cmnd,
+							cmdinfo->stream);
+		if (!cmdinfo->cmd_urb)
+			return SCSI_MLQUEUE_DEVICE_BUSY;
+		cmdinfo->state &= ~ALLOC_CMD_URB;
+	}
+
+	if (cmdinfo->state & SUBMIT_CMD_URB) {
+		if (usb_submit_urb(cmdinfo->cmd_urb, gfp)) {
+			scmd_printk(KERN_INFO, cmnd,
+					"cmd urb submission failure\n");
+			return SCSI_MLQUEUE_DEVICE_BUSY;
+		}
+		cmdinfo->state &= ~SUBMIT_CMD_URB;
+	}
+
+	return 0;
+}
+
+static int uas_queuecommand_lck(struct scsi_cmnd *cmnd,
+					void (*done)(struct scsi_cmnd *))
+{
+	struct scsi_device *sdev = cmnd->device;
+	struct uas_dev_info *devinfo = sdev->hostdata;
+	struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
+	int err;
+
+	BUILD_BUG_ON(sizeof(struct uas_cmd_info) > sizeof(struct scsi_pointer));
+
+	if (devinfo->cmnd)
+		return SCSI_MLQUEUE_DEVICE_BUSY;
+
+	if (blk_rq_tagged(cmnd->request)) {
+		cmdinfo->stream = cmnd->request->tag + 2;
+	} else {
+		devinfo->cmnd = cmnd;
+		cmdinfo->stream = 1;
+	}
+
+	cmnd->scsi_done = done;
+
+	cmdinfo->state = ALLOC_STATUS_URB | SUBMIT_STATUS_URB |
+			ALLOC_CMD_URB | SUBMIT_CMD_URB;
+
+	switch (cmnd->sc_data_direction) {
+	case DMA_FROM_DEVICE:
+		cmdinfo->state |= ALLOC_DATA_IN_URB | SUBMIT_DATA_IN_URB;
+		break;
+	case DMA_BIDIRECTIONAL:
+		cmdinfo->state |= ALLOC_DATA_IN_URB | SUBMIT_DATA_IN_URB;
+	case DMA_TO_DEVICE:
+		cmdinfo->state |= ALLOC_DATA_OUT_URB | SUBMIT_DATA_OUT_URB;
+	case DMA_NONE:
+		break;
+	}
+
+	if (!devinfo->use_streams) {
+		cmdinfo->state &= ~(SUBMIT_DATA_IN_URB | SUBMIT_DATA_OUT_URB |
+				ALLOC_STATUS_URB | SUBMIT_STATUS_URB);
+		cmdinfo->stream = 0;
+	}
+
+	err = uas_submit_urbs(cmnd, devinfo, GFP_ATOMIC);
+	if (err) {
+		/* If we did nothing, give up now */
+		if (cmdinfo->state & SUBMIT_STATUS_URB) {
+			usb_free_urb(cmdinfo->status_urb);
+			return SCSI_MLQUEUE_DEVICE_BUSY;
+		}
+		spin_lock(&uas_work_lock);
+		list_add_tail(&cmdinfo->list, &uas_work_list);
+		spin_unlock(&uas_work_lock);
+		schedule_work(&uas_work);
+	}
+
+	return 0;
+}
+
+static DEF_SCSI_QCMD(uas_queuecommand)
+
+static int uas_eh_abort_handler(struct scsi_cmnd *cmnd)
+{
+	struct scsi_device *sdev = cmnd->device;
+	sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
+							cmnd->request->tag);
+
+/* XXX: Send ABORT TASK Task Management command */
+	return FAILED;
+}
+
+static int uas_eh_device_reset_handler(struct scsi_cmnd *cmnd)
+{
+	struct scsi_device *sdev = cmnd->device;
+	sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
+							cmnd->request->tag);
+
+/* XXX: Send LOGICAL UNIT RESET Task Management command */
+	return FAILED;
+}
+
+static int uas_eh_target_reset_handler(struct scsi_cmnd *cmnd)
+{
+	struct scsi_device *sdev = cmnd->device;
+	sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
+							cmnd->request->tag);
+
+/* XXX: Can we reset just the one USB interface?
+ * Would calling usb_set_interface() have the right effect?
+ */
+	return FAILED;
+}
+
+static int uas_eh_bus_reset_handler(struct scsi_cmnd *cmnd)
+{
+	struct scsi_device *sdev = cmnd->device;
+	struct uas_dev_info *devinfo = sdev->hostdata;
+	struct usb_device *udev = devinfo->udev;
+
+	sdev_printk(KERN_INFO, sdev, "%s tag %d\n", __func__,
+							cmnd->request->tag);
+
+	if (usb_reset_device(udev))
+		return SUCCESS;
+
+	return FAILED;
+}
+
+static int uas_slave_alloc(struct scsi_device *sdev)
+{
+	sdev->hostdata = (void *)sdev->host->hostdata[0];
+	return 0;
+}
+
+static int uas_slave_configure(struct scsi_device *sdev)
+{
+	struct uas_dev_info *devinfo = sdev->hostdata;
+	scsi_set_tag_type(sdev, MSG_ORDERED_TAG);
+	scsi_activate_tcq(sdev, devinfo->qdepth - 2);
+	return 0;
+}
+
+static struct scsi_host_template uas_host_template = {
+	.module = THIS_MODULE,
+	.name = "uas",
+	.queuecommand = uas_queuecommand,
+	.slave_alloc = uas_slave_alloc,
+	.slave_configure = uas_slave_configure,
+	.eh_abort_handler = uas_eh_abort_handler,
+	.eh_device_reset_handler = uas_eh_device_reset_handler,
+	.eh_target_reset_handler = uas_eh_target_reset_handler,
+	.eh_bus_reset_handler = uas_eh_bus_reset_handler,
+	.can_queue = 65536,	/* Is there a limit on the _host_ ? */
+	.this_id = -1,
+	.sg_tablesize = SG_NONE,
+	.cmd_per_lun = 1,	/* until we override it */
+	.skip_settle_delay = 1,
+	.ordered_tag = 1,
+};
+
+static struct usb_device_id uas_usb_ids[] = {
+	{ USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_BULK) },
+	{ USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_UAS) },
+	/* 0xaa is a prototype device I happen to have access to */
+	{ USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, 0xaa) },
+	{ }
+};
+MODULE_DEVICE_TABLE(usb, uas_usb_ids);
+
+static int uas_is_interface(struct usb_host_interface *intf)
+{
+	return (intf->desc.bInterfaceClass == USB_CLASS_MASS_STORAGE &&
+		intf->desc.bInterfaceSubClass == USB_SC_SCSI &&
+		intf->desc.bInterfaceProtocol == USB_PR_UAS);
+}
+
+static int uas_isnt_supported(struct usb_device *udev)
+{
+	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+
+	dev_warn(&udev->dev, "The driver for the USB controller %s does not "
+			"support scatter-gather which is\n",
+			hcd->driver->description);
+	dev_warn(&udev->dev, "required by the UAS driver. Please try an"
+			"alternative USB controller if you wish to use UAS.\n");
+	return -ENODEV;
+}
+
+static int uas_switch_interface(struct usb_device *udev,
+						struct usb_interface *intf)
+{
+	int i;
+	int sg_supported = udev->bus->sg_tablesize != 0;
+
+	for (i = 0; i < intf->num_altsetting; i++) {
+		struct usb_host_interface *alt = &intf->altsetting[i];
+
+		if (uas_is_interface(alt)) {
+			if (!sg_supported)
+				return uas_isnt_supported(udev);
+			return usb_set_interface(udev,
+						alt->desc.bInterfaceNumber,
+						alt->desc.bAlternateSetting);
+		}
+	}
+
+	return -ENODEV;
+}
+
+static void uas_configure_endpoints(struct uas_dev_info *devinfo)
+{
+	struct usb_host_endpoint *eps[4] = { };
+	struct usb_interface *intf = devinfo->intf;
+	struct usb_device *udev = devinfo->udev;
+	struct usb_host_endpoint *endpoint = intf->cur_altsetting->endpoint;
+	unsigned i, n_endpoints = intf->cur_altsetting->desc.bNumEndpoints;
+
+	devinfo->uas_sense_old = 0;
+	devinfo->cmnd = NULL;
+
+	for (i = 0; i < n_endpoints; i++) {
+		unsigned char *extra = endpoint[i].extra;
+		int len = endpoint[i].extralen;
+		while (len > 1) {
+			if (extra[1] == USB_DT_PIPE_USAGE) {
+				unsigned pipe_id = extra[2];
+				if (pipe_id > 0 && pipe_id < 5)
+					eps[pipe_id - 1] = &endpoint[i];
+				break;
+			}
+			len -= extra[0];
+			extra += extra[0];
+		}
+	}
+
+	/*
+	 * Assume that if we didn't find a control pipe descriptor, we're
+	 * using a device with old firmware that happens to be set up like
+	 * this.
+	 */
+	if (!eps[0]) {
+		devinfo->cmd_pipe = usb_sndbulkpipe(udev, 1);
+		devinfo->status_pipe = usb_rcvbulkpipe(udev, 1);
+		devinfo->data_in_pipe = usb_rcvbulkpipe(udev, 2);
+		devinfo->data_out_pipe = usb_sndbulkpipe(udev, 2);
+
+		eps[1] = usb_pipe_endpoint(udev, devinfo->status_pipe);
+		eps[2] = usb_pipe_endpoint(udev, devinfo->data_in_pipe);
+		eps[3] = usb_pipe_endpoint(udev, devinfo->data_out_pipe);
+	} else {
+		devinfo->cmd_pipe = usb_sndbulkpipe(udev,
+						eps[0]->desc.bEndpointAddress);
+		devinfo->status_pipe = usb_rcvbulkpipe(udev,
+						eps[1]->desc.bEndpointAddress);
+		devinfo->data_in_pipe = usb_rcvbulkpipe(udev,
+						eps[2]->desc.bEndpointAddress);
+		devinfo->data_out_pipe = usb_sndbulkpipe(udev,
+						eps[3]->desc.bEndpointAddress);
+	}
+
+	devinfo->qdepth = usb_alloc_streams(devinfo->intf, eps + 1, 3, 256,
+								GFP_KERNEL);
+	if (devinfo->qdepth < 0) {
+		devinfo->qdepth = 256;
+		devinfo->use_streams = 0;
+	} else {
+		devinfo->use_streams = 1;
+	}
+}
+
+static int uas_alloc_status_urb(struct uas_dev_info *devinfo,
+		struct Scsi_Host *shost)
+{
+	if (devinfo->use_streams) {
+		devinfo->status_urb = NULL;
+		return 0;
+	}
+
+	devinfo->status_urb = uas_alloc_sense_urb(devinfo, GFP_KERNEL,
+			shost, 0);
+	if (!devinfo->status_urb)
+		goto err_s_urb;
+
+	if (usb_submit_urb(devinfo->status_urb, GFP_KERNEL))
+		goto err_submit_urb;
+
+	return 0;
+err_submit_urb:
+	usb_free_urb(devinfo->status_urb);
+err_s_urb:
+	return -ENOMEM;
+}
+
+static void uas_free_streams(struct uas_dev_info *devinfo)
+{
+	struct usb_device *udev = devinfo->udev;
+	struct usb_host_endpoint *eps[3];
+
+	eps[0] = usb_pipe_endpoint(udev, devinfo->status_pipe);
+	eps[1] = usb_pipe_endpoint(udev, devinfo->data_in_pipe);
+	eps[2] = usb_pipe_endpoint(udev, devinfo->data_out_pipe);
+	usb_free_streams(devinfo->intf, eps, 3, GFP_KERNEL);
+}
+
+/*
+ * XXX: What I'd like to do here is register a SCSI host for each USB host in
+ * the system.  Follow usb-storage's design of registering a SCSI host for
+ * each USB device for the moment.  Can implement this by walking up the
+ * USB hierarchy until we find a USB host.
+ */
+static int uas_probe(struct usb_interface *intf, const struct usb_device_id *id)
+{
+	int result;
+	struct Scsi_Host *shost;
+	struct uas_dev_info *devinfo;
+	struct usb_device *udev = interface_to_usbdev(intf);
+
+	if (uas_switch_interface(udev, intf))
+		return -ENODEV;
+
+	devinfo = kmalloc(sizeof(struct uas_dev_info), GFP_KERNEL);
+	if (!devinfo)
+		return -ENOMEM;
+
+	result = -ENOMEM;
+	shost = scsi_host_alloc(&uas_host_template, sizeof(void *));
+	if (!shost)
+		goto free;
+
+	shost->max_cmd_len = 16 + 252;
+	shost->max_id = 1;
+	shost->sg_tablesize = udev->bus->sg_tablesize;
+
+	devinfo->intf = intf;
+	devinfo->udev = udev;
+	uas_configure_endpoints(devinfo);
+
+	result = scsi_init_shared_tag_map(shost, devinfo->qdepth - 2);
+	if (result)
+		goto free;
+
+	result = scsi_add_host(shost, &intf->dev);
+	if (result)
+		goto deconfig_eps;
+
+	shost->hostdata[0] = (unsigned long)devinfo;
+
+	result = uas_alloc_status_urb(devinfo, shost);
+	if (result)
+		goto err_alloc_status;
+
+	scsi_scan_host(shost);
+	usb_set_intfdata(intf, shost);
+	return result;
+
+err_alloc_status:
+	scsi_remove_host(shost);
+	shost = NULL;
+deconfig_eps:
+	uas_free_streams(devinfo);
+ free:
+	kfree(devinfo);
+	if (shost)
+		scsi_host_put(shost);
+	return result;
+}
+
+static int uas_pre_reset(struct usb_interface *intf)
+{
+/* XXX: Need to return 1 if it's not our device in error handling */
+	return 0;
+}
+
+static int uas_post_reset(struct usb_interface *intf)
+{
+/* XXX: Need to return 1 if it's not our device in error handling */
+	return 0;
+}
+
+static void uas_disconnect(struct usb_interface *intf)
+{
+	struct Scsi_Host *shost = usb_get_intfdata(intf);
+	struct uas_dev_info *devinfo = (void *)shost->hostdata[0];
+
+	scsi_remove_host(shost);
+	usb_kill_urb(devinfo->status_urb);
+	usb_free_urb(devinfo->status_urb);
+	uas_free_streams(devinfo);
+	kfree(devinfo);
+}
+
+/*
+ * XXX: Should this plug into libusual so we can auto-upgrade devices from
+ * Bulk-Only to UAS?
+ */
+static struct usb_driver uas_driver = {
+	.name = "uas",
+	.probe = uas_probe,
+	.disconnect = uas_disconnect,
+	.pre_reset = uas_pre_reset,
+	.post_reset = uas_post_reset,
+	.id_table = uas_usb_ids,
+};
+
+module_usb_driver(uas_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Matthew Wilcox and Sarah Sharp");