1 files changed, 1215 insertions, 0 deletions

diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c
new file mode 100644
index 000000000000..d2c3d2fa082e
--- /dev/null
+++ b/drivers/usb/storage/transport.c
@@ -0,0 +1,1215 @@
+/* Driver for USB Mass Storage compliant devices
+ *
+ * $Id: transport.c,v 1.47 2002/04/22 03:39:43 mdharm Exp $
+ *
+ * Current development and maintenance by:
+ *   (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
+ *
+ * Developed with the assistance of:
+ *   (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org)
+ *   (c) 2000 Stephen J. Gowdy (SGowdy@lbl.gov)
+ *   (c) 2002 Alan Stern <stern@rowland.org>
+ *
+ * Initial work by:
+ *   (c) 1999 Michael Gee (michael@linuxspecific.com)
+ *
+ * This driver is based on the 'USB Mass Storage Class' document. This
+ * describes in detail the protocol used to communicate with such
+ * devices.  Clearly, the designers had SCSI and ATAPI commands in
+ * mind when they created this document.  The commands are all very
+ * similar to commands in the SCSI-II and ATAPI specifications.
+ *
+ * It is important to note that in a number of cases this class
+ * exhibits class-specific exemptions from the USB specification.
+ * Notably the usage of NAK, STALL and ACK differs from the norm, in
+ * that they are used to communicate wait, failed and OK on commands.
+ *
+ * Also, for certain devices, the interrupt endpoint is used to convey
+ * status of a command.
+ *
+ * Please see http://www.one-eyed-alien.net/~mdharm/linux-usb for more
+ * information about this driver.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/config.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+
+#include "usb.h"
+#include "transport.h"
+#include "protocol.h"
+#include "scsiglue.h"
+#include "debug.h"
+
+
+/***********************************************************************
+ * Data transfer routines
+ ***********************************************************************/
+
+/*
+ * This is subtle, so pay attention:
+ * ---------------------------------
+ * We're very concerned about races with a command abort.  Hanging this code
+ * is a sure fire way to hang the kernel.  (Note that this discussion applies
+ * only to transactions resulting from a scsi queued-command, since only
+ * these transactions are subject to a scsi abort.  Other transactions, such
+ * as those occurring during device-specific initialization, must be handled
+ * by a separate code path.)
+ *
+ * The abort function (usb_storage_command_abort() in scsiglue.c) first
+ * sets the machine state and the ABORTING bit in us->flags to prevent
+ * new URBs from being submitted.  It then calls usb_stor_stop_transport()
+ * below, which atomically tests-and-clears the URB_ACTIVE bit in us->flags
+ * to see if the current_urb needs to be stopped.  Likewise, the SG_ACTIVE
+ * bit is tested to see if the current_sg scatter-gather request needs to be
+ * stopped.  The timeout callback routine does much the same thing.
+ *
+ * When a disconnect occurs, the DISCONNECTING bit in us->flags is set to
+ * prevent new URBs from being submitted, and usb_stor_stop_transport() is
+ * called to stop any ongoing requests.
+ *
+ * The submit function first verifies that the submitting is allowed
+ * (neither ABORTING nor DISCONNECTING bits are set) and that the submit
+ * completes without errors, and only then sets the URB_ACTIVE bit.  This
+ * prevents the stop_transport() function from trying to cancel the URB
+ * while the submit call is underway.  Next, the submit function must test
+ * the flags to see if an abort or disconnect occurred during the submission
+ * or before the URB_ACTIVE bit was set.  If so, it's essential to cancel
+ * the URB if it hasn't been cancelled already (i.e., if the URB_ACTIVE bit
+ * is still set).  Either way, the function must then wait for the URB to
+ * finish.  Note that because the URB_ASYNC_UNLINK flag is set, the URB can
+ * still be in progress even after a call to usb_unlink_urb() returns.
+ *
+ * The idea is that (1) once the ABORTING or DISCONNECTING bit is set,
+ * either the stop_transport() function or the submitting function
+ * is guaranteed to call usb_unlink_urb() for an active URB,
+ * and (2) test_and_clear_bit() prevents usb_unlink_urb() from being
+ * called more than once or from being called during usb_submit_urb().
+ */
+
+/* This is the completion handler which will wake us up when an URB
+ * completes.
+ */
+static void usb_stor_blocking_completion(struct urb *urb, struct pt_regs *regs)
+{
+        struct completion *urb_done_ptr = (struct completion *)urb->context;
+
+        complete(urb_done_ptr);
+}
+ 
+/* This is the timeout handler which will cancel an URB when its timeout
+ * expires.
+ */
+static void timeout_handler(unsigned long us_)
+{
+        struct us_data *us = (struct us_data *) us_;
+
+        if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->flags)) {
+                US_DEBUGP("Timeout -- cancelling URB\n");
+                usb_unlink_urb(us->current_urb);
+        }
+}
+
+/* This is the common part of the URB message submission code
+ *
+ * All URBs from the usb-storage driver involved in handling a queued scsi
+ * command _must_ pass through this function (or something like it) for the
+ * abort mechanisms to work properly.
+ */
+static int usb_stor_msg_common(struct us_data *us, int timeout)
+{
+        struct completion urb_done;
+        struct timer_list to_timer;
+        int status;
+
+        /* don't submit URBs during abort/disconnect processing */
+        if (us->flags & ABORTING_OR_DISCONNECTING)
+                return -EIO;
+
+        /* set up data structures for the wakeup system */
+        init_completion(&urb_done);
+
+        /* fill the common fields in the URB */
+        us->current_urb->context = &urb_done;
+        us->current_urb->actual_length = 0;
+        us->current_urb->error_count = 0;
+        us->current_urb->status = 0;
+
+        /* we assume that if transfer_buffer isn't us->iobuf then it
+         * hasn't been mapped for DMA.  Yes, this is clunky, but it's
+         * easier than always having the caller tell us whether the
+         * transfer buffer has already been mapped. */
+        us->current_urb->transfer_flags =
+                        URB_ASYNC_UNLINK | URB_NO_SETUP_DMA_MAP;
+        if (us->current_urb->transfer_buffer == us->iobuf)
+                us->current_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+        us->current_urb->transfer_dma = us->iobuf_dma;
+        us->current_urb->setup_dma = us->cr_dma;
+
+        /* submit the URB */
+        status = usb_submit_urb(us->current_urb, GFP_NOIO);
+        if (status) {
+                /* something went wrong */
+                return status;
+        }
+
+        /* since the URB has been submitted successfully, it's now okay
+         * to cancel it */
+        set_bit(US_FLIDX_URB_ACTIVE, &us->flags);
+
+        /* did an abort/disconnect occur during the submission? */
+        if (us->flags & ABORTING_OR_DISCONNECTING) {
+
+                /* cancel the URB, if it hasn't been cancelled already */
+                if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->flags)) {
+                        US_DEBUGP("-- cancelling URB\n");
+                        usb_unlink_urb(us->current_urb);
+                }
+        }
+ 
+        /* submit the timeout timer, if a timeout was requested */
+        if (timeout > 0) {
+                init_timer(&to_timer);
+                to_timer.expires = jiffies + timeout;
+                to_timer.function = timeout_handler;
+                to_timer.data = (unsigned long) us;
+                add_timer(&to_timer);
+        }
+
+        /* wait for the completion of the URB */
+        wait_for_completion(&urb_done);
+        clear_bit(US_FLIDX_URB_ACTIVE, &us->flags);
+ 
+        /* clean up the timeout timer */
+        if (timeout > 0)
+                del_timer_sync(&to_timer);
+
+        /* return the URB status */
+        return us->current_urb->status;
+}
+
+/*
+ * Transfer one control message, with timeouts, and allowing early
+ * termination.  Return codes are usual -Exxx, *not* USB_STOR_XFER_xxx.
+ */
+int usb_stor_control_msg(struct us_data *us, unsigned int pipe,
+                 u8 request, u8 requesttype, u16 value, u16 index, 
+                 void *data, u16 size, int timeout)
+{
+        int status;
+
+        US_DEBUGP("%s: rq=%02x rqtype=%02x value=%04x index=%02x len=%u\n",
+                        __FUNCTION__, request, requesttype,
+                        value, index, size);
+
+        /* fill in the devrequest structure */
+        us->cr->bRequestType = requesttype;
+        us->cr->bRequest = request;
+        us->cr->wValue = cpu_to_le16(value);
+        us->cr->wIndex = cpu_to_le16(index);
+        us->cr->wLength = cpu_to_le16(size);
+
+        /* fill and submit the URB */
+        usb_fill_control_urb(us->current_urb, us->pusb_dev, pipe, 
+                         (unsigned char*) us->cr, data, size, 
+                         usb_stor_blocking_completion, NULL);
+        status = usb_stor_msg_common(us, timeout);
+
+        /* return the actual length of the data transferred if no error */
+        if (status == 0)
+                status = us->current_urb->actual_length;
+        return status;
+}
+
+/* This is a version of usb_clear_halt() that allows early termination and
+ * doesn't read the status from the device -- this is because some devices
+ * crash their internal firmware when the status is requested after a halt.
+ *
+ * A definitive list of these 'bad' devices is too difficult to maintain or
+ * make complete enough to be useful.  This problem was first observed on the
+ * Hagiwara FlashGate DUAL unit.  However, bus traces reveal that neither
+ * MacOS nor Windows checks the status after clearing a halt.
+ *
+ * Since many vendors in this space limit their testing to interoperability
+ * with these two OSes, specification violations like this one are common.
+ */
+int usb_stor_clear_halt(struct us_data *us, unsigned int pipe)
+{
+        int result;
+        int endp = usb_pipeendpoint(pipe);
+
+        if (usb_pipein (pipe))
+                endp |= USB_DIR_IN;
+
+        result = usb_stor_control_msg(us, us->send_ctrl_pipe,
+                USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT,
+                USB_ENDPOINT_HALT, endp,
+                NULL, 0, 3*HZ);
+
+        /* reset the endpoint toggle */
+        usb_settoggle(us->pusb_dev, usb_pipeendpoint(pipe),
+                usb_pipeout(pipe), 0);
+
+        US_DEBUGP("%s: result = %d\n", __FUNCTION__, result);
+        return result;
+}
+
+
+/*
+ * Interpret the results of a URB transfer
+ *
+ * This function prints appropriate debugging messages, clears halts on
+ * non-control endpoints, and translates the status to the corresponding
+ * USB_STOR_XFER_xxx return code.
+ */
+static int interpret_urb_result(struct us_data *us, unsigned int pipe,
+                unsigned int length, int result, unsigned int partial)
+{
+        US_DEBUGP("Status code %d; transferred %u/%u\n",
+                        result, partial, length);
+        switch (result) {
+
+        /* no error code; did we send all the data? */
+        case 0:
+                if (partial != length) {
+                        US_DEBUGP("-- short transfer\n");
+                        return USB_STOR_XFER_SHORT;
+                }
+
+                US_DEBUGP("-- transfer complete\n");
+                return USB_STOR_XFER_GOOD;
+
+        /* stalled */
+        case -EPIPE:
+                /* for control endpoints, (used by CB[I]) a stall indicates
+                 * a failed command */
+                if (usb_pipecontrol(pipe)) {
+                        US_DEBUGP("-- stall on control pipe\n");
+                        return USB_STOR_XFER_STALLED;
+                }
+
+                /* for other sorts of endpoint, clear the stall */
+                US_DEBUGP("clearing endpoint halt for pipe 0x%x\n", pipe);
+                if (usb_stor_clear_halt(us, pipe) < 0)
+                        return USB_STOR_XFER_ERROR;
+                return USB_STOR_XFER_STALLED;
+
+        /* timeout or excessively long NAK */
+        case -ETIMEDOUT:
+                US_DEBUGP("-- timeout or NAK\n");
+                return USB_STOR_XFER_ERROR;
+
+        /* babble - the device tried to send more than we wanted to read */
+        case -EOVERFLOW:
+                US_DEBUGP("-- babble\n");
+                return USB_STOR_XFER_LONG;
+
+        /* the transfer was cancelled by abort, disconnect, or timeout */
+        case -ECONNRESET:
+                US_DEBUGP("-- transfer cancelled\n");
+                return USB_STOR_XFER_ERROR;
+
+        /* short scatter-gather read transfer */
+        case -EREMOTEIO:
+                US_DEBUGP("-- short read transfer\n");
+                return USB_STOR_XFER_SHORT;
+
+        /* abort or disconnect in progress */
+        case -EIO:
+                US_DEBUGP("-- abort or disconnect in progress\n");
+                return USB_STOR_XFER_ERROR;
+
+        /* the catch-all error case */
+        default:
+                US_DEBUGP("-- unknown error\n");
+                return USB_STOR_XFER_ERROR;
+        }
+}
+
+/*
+ * Transfer one control message, without timeouts, but allowing early
+ * termination.  Return codes are USB_STOR_XFER_xxx.
+ */
+int usb_stor_ctrl_transfer(struct us_data *us, unsigned int pipe,
+                u8 request, u8 requesttype, u16 value, u16 index,
+                void *data, u16 size)
+{
+        int result;
+
+        US_DEBUGP("%s: rq=%02x rqtype=%02x value=%04x index=%02x len=%u\n",
+                        __FUNCTION__, request, requesttype,
+                        value, index, size);
+
+        /* fill in the devrequest structure */
+        us->cr->bRequestType = requesttype;
+        us->cr->bRequest = request;
+        us->cr->wValue = cpu_to_le16(value);
+        us->cr->wIndex = cpu_to_le16(index);
+        us->cr->wLength = cpu_to_le16(size);
+
+        /* fill and submit the URB */
+        usb_fill_control_urb(us->current_urb, us->pusb_dev, pipe, 
+                         (unsigned char*) us->cr, data, size, 
+                         usb_stor_blocking_completion, NULL);
+        result = usb_stor_msg_common(us, 0);
+
+        return interpret_urb_result(us, pipe, size, result,
+                        us->current_urb->actual_length);
+}
+
+/*
+ * Receive one interrupt buffer, without timeouts, but allowing early
+ * termination.  Return codes are USB_STOR_XFER_xxx.
+ *
+ * This routine always uses us->recv_intr_pipe as the pipe and
+ * us->ep_bInterval as the interrupt interval.
+ */
+static int usb_stor_intr_transfer(struct us_data *us, void *buf,
+                                  unsigned int length)
+{
+        int result;
+        unsigned int pipe = us->recv_intr_pipe;
+        unsigned int maxp;
+
+        US_DEBUGP("%s: xfer %u bytes\n", __FUNCTION__, length);
+
+        /* calculate the max packet size */
+        maxp = usb_maxpacket(us->pusb_dev, pipe, usb_pipeout(pipe));
+        if (maxp > length)
+                maxp = length;
+
+        /* fill and submit the URB */
+        usb_fill_int_urb(us->current_urb, us->pusb_dev, pipe, buf,
+                        maxp, usb_stor_blocking_completion, NULL,
+                        us->ep_bInterval);
+        result = usb_stor_msg_common(us, 0);
+
+        return interpret_urb_result(us, pipe, length, result,
+                        us->current_urb->actual_length);
+}
+
+/*
+ * Transfer one buffer via bulk pipe, without timeouts, but allowing early
+ * termination.  Return codes are USB_STOR_XFER_xxx.  If the bulk pipe
+ * stalls during the transfer, the halt is automatically cleared.
+ */
+int usb_stor_bulk_transfer_buf(struct us_data *us, unsigned int pipe,
+        void *buf, unsigned int length, unsigned int *act_len)
+{
+        int result;
+
+        US_DEBUGP("%s: xfer %u bytes\n", __FUNCTION__, length);
+
+        /* fill and submit the URB */
+        usb_fill_bulk_urb(us->current_urb, us->pusb_dev, pipe, buf, length,
+                      usb_stor_blocking_completion, NULL);
+        result = usb_stor_msg_common(us, 0);
+
+        /* store the actual length of the data transferred */
+        if (act_len)
+                *act_len = us->current_urb->actual_length;
+        return interpret_urb_result(us, pipe, length, result, 
+                        us->current_urb->actual_length);
+}
+
+/*
+ * Transfer a scatter-gather list via bulk transfer
+ *
+ * This function does basically the same thing as usb_stor_bulk_transfer_buf()
+ * above, but it uses the usbcore scatter-gather library.
+ */
+static int usb_stor_bulk_transfer_sglist(struct us_data *us, unsigned int pipe,
+                struct scatterlist *sg, int num_sg, unsigned int length,
+                unsigned int *act_len)
+{
+        int result;
+
+        /* don't submit s-g requests during abort/disconnect processing */
+        if (us->flags & ABORTING_OR_DISCONNECTING)
+                return USB_STOR_XFER_ERROR;
+
+        /* initialize the scatter-gather request block */
+        US_DEBUGP("%s: xfer %u bytes, %d entries\n", __FUNCTION__,
+                        length, num_sg);
+        result = usb_sg_init(&us->current_sg, us->pusb_dev, pipe, 0,
+                        sg, num_sg, length, SLAB_NOIO);
+        if (result) {
+                US_DEBUGP("usb_sg_init returned %d\n", result);
+                return USB_STOR_XFER_ERROR;
+        }
+
+        /* since the block has been initialized successfully, it's now
+         * okay to cancel it */
+        set_bit(US_FLIDX_SG_ACTIVE, &us->flags);
+
+        /* did an abort/disconnect occur during the submission? */
+        if (us->flags & ABORTING_OR_DISCONNECTING) {
+
+                /* cancel the request, if it hasn't been cancelled already */
+                if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->flags)) {
+                        US_DEBUGP("-- cancelling sg request\n");
+                        usb_sg_cancel(&us->current_sg);
+                }
+        }
+
+        /* wait for the completion of the transfer */
+        usb_sg_wait(&us->current_sg);
+        clear_bit(US_FLIDX_SG_ACTIVE, &us->flags);
+
+        result = us->current_sg.status;
+        if (act_len)
+                *act_len = us->current_sg.bytes;
+        return interpret_urb_result(us, pipe, length, result,
+                        us->current_sg.bytes);
+}
+
+/*
+ * Transfer an entire SCSI command's worth of data payload over the bulk
+ * pipe.
+ *
+ * Note that this uses usb_stor_bulk_transfer_buf() and
+ * usb_stor_bulk_transfer_sglist() to achieve its goals --
+ * this function simply determines whether we're going to use
+ * scatter-gather or not, and acts appropriately.
+ */
+int usb_stor_bulk_transfer_sg(struct us_data* us, unsigned int pipe,
+                void *buf, unsigned int length_left, int use_sg, int *residual)
+{
+        int result;
+        unsigned int partial;
+
+        /* are we scatter-gathering? */
+        if (use_sg) {
+                /* use the usb core scatter-gather primitives */
+                result = usb_stor_bulk_transfer_sglist(us, pipe,
+                                (struct scatterlist *) buf, use_sg,
+                                length_left, &partial);
+                length_left -= partial;
+        } else {
+                /* no scatter-gather, just make the request */
+                result = usb_stor_bulk_transfer_buf(us, pipe, buf, 
+                                length_left, &partial);
+                length_left -= partial;
+        }
+
+        /* store the residual and return the error code */
+        if (residual)
+                *residual = length_left;
+        return result;
+}
+
+/***********************************************************************
+ * Transport routines
+ ***********************************************************************/
+
+/* Invoke the transport and basic error-handling/recovery methods
+ *
+ * This is used by the protocol layers to actually send the message to
+ * the device and receive the response.
+ */
+void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
+{
+        int need_auto_sense;
+        int result;
+
+        /* send the command to the transport layer */
+        srb->resid = 0;
+        result = us->transport(srb, us);
+
+        /* if the command gets aborted by the higher layers, we need to
+         * short-circuit all other processing
+         */
+        if (test_bit(US_FLIDX_TIMED_OUT, &us->flags)) {
+                US_DEBUGP("-- command was aborted\n");
+                goto Handle_Abort;
+        }
+
+        /* if there is a transport error, reset and don't auto-sense */
+        if (result == USB_STOR_TRANSPORT_ERROR) {
+                US_DEBUGP("-- transport indicates error, resetting\n");
+                us->transport_reset(us);
+                srb->result = DID_ERROR << 16;
+                return;
+        }
+
+        /* if the transport provided its own sense data, don't auto-sense */
+        if (result == USB_STOR_TRANSPORT_NO_SENSE) {
+                srb->result = SAM_STAT_CHECK_CONDITION;
+                return;
+        }
+
+        srb->result = SAM_STAT_GOOD;
+
+        /* Determine if we need to auto-sense
+         *
+         * I normally don't use a flag like this, but it's almost impossible
+         * to understand what's going on here if I don't.
+         */
+        need_auto_sense = 0;
+
+        /*
+         * If we're running the CB transport, which is incapable
+         * of determining status on its own, we will auto-sense
+         * unless the operation involved a data-in transfer.  Devices
+         * can signal most data-in errors by stalling the bulk-in pipe.
+         */
+        if ((us->protocol == US_PR_CB || us->protocol == US_PR_DPCM_USB) &&
+                        srb->sc_data_direction != DMA_FROM_DEVICE) {
+                US_DEBUGP("-- CB transport device requiring auto-sense\n");
+                need_auto_sense = 1;
+        }
+
+        /*
+         * If we have a failure, we're going to do a REQUEST_SENSE 
+         * automatically.  Note that we differentiate between a command
+         * "failure" and an "error" in the transport mechanism.
+         */
+        if (result == USB_STOR_TRANSPORT_FAILED) {
+                US_DEBUGP("-- transport indicates command failure\n");
+                need_auto_sense = 1;
+        }
+
+        /*
+         * A short transfer on a command where we don't expect it
+         * is unusual, but it doesn't mean we need to auto-sense.
+         */
+        if ((srb->resid > 0) &&
+            !((srb->cmnd[0] == REQUEST_SENSE) ||
+              (srb->cmnd[0] == INQUIRY) ||
+              (srb->cmnd[0] == MODE_SENSE) ||
+              (srb->cmnd[0] == LOG_SENSE) ||
+              (srb->cmnd[0] == MODE_SENSE_10))) {
+                US_DEBUGP("-- unexpectedly short transfer\n");
+        }
+
+        /* Now, if we need to do the auto-sense, let's do it */
+        if (need_auto_sense) {
+                int temp_result;
+                void* old_request_buffer;
+                unsigned short old_sg;
+                unsigned old_request_bufflen;
+                unsigned char old_sc_data_direction;
+                unsigned char old_cmd_len;
+                unsigned char old_cmnd[MAX_COMMAND_SIZE];
+                unsigned long old_serial_number;
+                int old_resid;
+
+                US_DEBUGP("Issuing auto-REQUEST_SENSE\n");
+
+                /* save the old command */
+                memcpy(old_cmnd, srb->cmnd, MAX_COMMAND_SIZE);
+                old_cmd_len = srb->cmd_len;
+
+                /* set the command and the LUN */
+                memset(srb->cmnd, 0, MAX_COMMAND_SIZE);
+                srb->cmnd[0] = REQUEST_SENSE;
+                srb->cmnd[1] = old_cmnd[1] & 0xE0;
+                srb->cmnd[4] = 18;
+
+                /* FIXME: we must do the protocol translation here */
+                if (us->subclass == US_SC_RBC || us->subclass == US_SC_SCSI)
+                        srb->cmd_len = 6;
+                else
+                        srb->cmd_len = 12;
+
+                /* set the transfer direction */
+                old_sc_data_direction = srb->sc_data_direction;
+                srb->sc_data_direction = DMA_FROM_DEVICE;
+
+                /* use the new buffer we have */
+                old_request_buffer = srb->request_buffer;
+                srb->request_buffer = srb->sense_buffer;
+
+                /* set the buffer length for transfer */
+                old_request_bufflen = srb->request_bufflen;
+                srb->request_bufflen = 18;
+
+                /* set up for no scatter-gather use */
+                old_sg = srb->use_sg;
+                srb->use_sg = 0;
+
+                /* change the serial number -- toggle the high bit*/
+                old_serial_number = srb->serial_number;
+                srb->serial_number ^= 0x80000000;
+
+                /* issue the auto-sense command */
+                old_resid = srb->resid;
+                srb->resid = 0;
+                temp_result = us->transport(us->srb, us);
+
+                /* let's clean up right away */
+                srb->resid = old_resid;
+                srb->request_buffer = old_request_buffer;
+                srb->request_bufflen = old_request_bufflen;
+                srb->use_sg = old_sg;
+                srb->serial_number = old_serial_number;
+                srb->sc_data_direction = old_sc_data_direction;
+                srb->cmd_len = old_cmd_len;
+                memcpy(srb->cmnd, old_cmnd, MAX_COMMAND_SIZE);
+
+                if (test_bit(US_FLIDX_TIMED_OUT, &us->flags)) {
+                        US_DEBUGP("-- auto-sense aborted\n");
+                        goto Handle_Abort;
+                }
+                if (temp_result != USB_STOR_TRANSPORT_GOOD) {
+                        US_DEBUGP("-- auto-sense failure\n");
+
+                        /* we skip the reset if this happens to be a
+                         * multi-target device, since failure of an
+                         * auto-sense is perfectly valid
+                         */
+                        if (!(us->flags & US_FL_SCM_MULT_TARG))
+                                us->transport_reset(us);
+                        srb->result = DID_ERROR << 16;
+                        return;
+                }
+
+                US_DEBUGP("-- Result from auto-sense is %d\n", temp_result);
+                US_DEBUGP("-- code: 0x%x, key: 0x%x, ASC: 0x%x, ASCQ: 0x%x\n",
+                          srb->sense_buffer[0],
+                          srb->sense_buffer[2] & 0xf,
+                          srb->sense_buffer[12], 
+                          srb->sense_buffer[13]);
+#ifdef CONFIG_USB_STORAGE_DEBUG
+                usb_stor_show_sense(
+                          srb->sense_buffer[2] & 0xf,
+                          srb->sense_buffer[12], 
+                          srb->sense_buffer[13]);
+#endif
+
+                /* set the result so the higher layers expect this data */
+                srb->result = SAM_STAT_CHECK_CONDITION;
+
+                /* If things are really okay, then let's show that.  Zero
+                 * out the sense buffer so the higher layers won't realize
+                 * we did an unsolicited auto-sense. */
+                if (result == USB_STOR_TRANSPORT_GOOD &&
+                        /* Filemark 0, ignore EOM, ILI 0, no sense */
+                                (srb->sense_buffer[2] & 0xaf) == 0 &&
+                        /* No ASC or ASCQ */
+                                srb->sense_buffer[12] == 0 &&
+                                srb->sense_buffer[13] == 0) {
+                        srb->result = SAM_STAT_GOOD;
+                        srb->sense_buffer[0] = 0x0;
+                }
+        }
+
+        /* Did we transfer less than the minimum amount required? */
+        if (srb->result == SAM_STAT_GOOD &&
+                        srb->request_bufflen - srb->resid < srb->underflow)
+                srb->result = (DID_ERROR << 16) | (SUGGEST_RETRY << 24);
+
+        return;
+
+        /* abort processing: the bulk-only transport requires a reset
+         * following an abort */
+  Handle_Abort:
+        srb->result = DID_ABORT << 16;
+        if (us->protocol == US_PR_BULK)
+                us->transport_reset(us);
+}
+
+/* Stop the current URB transfer */
+void usb_stor_stop_transport(struct us_data *us)
+{
+        US_DEBUGP("%s called\n", __FUNCTION__);
+
+        /* If the state machine is blocked waiting for an URB,
+         * let's wake it up.  The test_and_clear_bit() call
+         * guarantees that if a URB has just been submitted,
+         * it won't be cancelled more than once. */
+        if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->flags)) {
+                US_DEBUGP("-- cancelling URB\n");
+                usb_unlink_urb(us->current_urb);
+        }
+
+        /* If we are waiting for a scatter-gather operation, cancel it. */
+        if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->flags)) {
+                US_DEBUGP("-- cancelling sg request\n");
+                usb_sg_cancel(&us->current_sg);
+        }
+}
+
+/*
+ * Control/Bulk/Interrupt transport
+ */
+
+int usb_stor_CBI_transport(struct scsi_cmnd *srb, struct us_data *us)
+{
+        unsigned int transfer_length = srb->request_bufflen;
+        unsigned int pipe = 0;
+        int result;
+
+        /* COMMAND STAGE */
+        /* let's send the command via the control pipe */
+        result = usb_stor_ctrl_transfer(us, us->send_ctrl_pipe,
+                                      US_CBI_ADSC, 
+                                      USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0, 
+                                      us->ifnum, srb->cmnd, srb->cmd_len);
+
+        /* check the return code for the command */
+        US_DEBUGP("Call to usb_stor_ctrl_transfer() returned %d\n", result);
+
+        /* if we stalled the command, it means command failed */
+        if (result == USB_STOR_XFER_STALLED) {
+                return USB_STOR_TRANSPORT_FAILED;
+        }
+
+        /* Uh oh... serious problem here */
+        if (result != USB_STOR_XFER_GOOD) {
+                return USB_STOR_TRANSPORT_ERROR;
+        }
+
+        /* DATA STAGE */
+        /* transfer the data payload for this command, if one exists*/
+        if (transfer_length) {
+                pipe = srb->sc_data_direction == DMA_FROM_DEVICE ? 
+                                us->recv_bulk_pipe : us->send_bulk_pipe;
+                result = usb_stor_bulk_transfer_sg(us, pipe,
+                                        srb->request_buffer, transfer_length,
+                                        srb->use_sg, &srb->resid);
+                US_DEBUGP("CBI data stage result is 0x%x\n", result);
+
+                /* if we stalled the data transfer it means command failed */
+                if (result == USB_STOR_XFER_STALLED)
+                        return USB_STOR_TRANSPORT_FAILED;
+                if (result > USB_STOR_XFER_STALLED)
+                        return USB_STOR_TRANSPORT_ERROR;
+        }
+
+        /* STATUS STAGE */
+        result = usb_stor_intr_transfer(us, us->iobuf, 2);
+        US_DEBUGP("Got interrupt data (0x%x, 0x%x)\n", 
+                        us->iobuf[0], us->iobuf[1]);
+        if (result != USB_STOR_XFER_GOOD)
+                return USB_STOR_TRANSPORT_ERROR;
+
+        /* UFI gives us ASC and ASCQ, like a request sense
+         *
+         * REQUEST_SENSE and INQUIRY don't affect the sense data on UFI
+         * devices, so we ignore the information for those commands.  Note
+         * that this means we could be ignoring a real error on these
+         * commands, but that can't be helped.
+         */
+        if (us->subclass == US_SC_UFI) {
+                if (srb->cmnd[0] == REQUEST_SENSE ||
+                    srb->cmnd[0] == INQUIRY)
+                        return USB_STOR_TRANSPORT_GOOD;
+                if (us->iobuf[0])
+                        goto Failed;
+                return USB_STOR_TRANSPORT_GOOD;
+        }
+
+        /* If not UFI, we interpret the data as a result code 
+         * The first byte should always be a 0x0.
+         *
+         * Some bogus devices don't follow that rule.  They stuff the ASC
+         * into the first byte -- so if it's non-zero, call it a failure.
+         */
+        if (us->iobuf[0]) {
+                US_DEBUGP("CBI IRQ data showed reserved bType 0x%x\n",
+                                us->iobuf[0]);
+                goto Failed;
+
+        }
+
+        /* The second byte & 0x0F should be 0x0 for good, otherwise error */
+        switch (us->iobuf[1] & 0x0F) {
+                case 0x00: 
+                        return USB_STOR_TRANSPORT_GOOD;
+                case 0x01: 
+                        goto Failed;
+        }
+        return USB_STOR_TRANSPORT_ERROR;
+
+        /* the CBI spec requires that the bulk pipe must be cleared
+         * following any data-in/out command failure (section 2.4.3.1.3)
+         */
+  Failed:
+        if (pipe)
+                usb_stor_clear_halt(us, pipe);
+        return USB_STOR_TRANSPORT_FAILED;
+}
+
+/*
+ * Control/Bulk transport
+ */
+int usb_stor_CB_transport(struct scsi_cmnd *srb, struct us_data *us)
+{
+        unsigned int transfer_length = srb->request_bufflen;
+        int result;
+
+        /* COMMAND STAGE */
+        /* let's send the command via the control pipe */
+        result = usb_stor_ctrl_transfer(us, us->send_ctrl_pipe,
+                                      US_CBI_ADSC, 
+                                      USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0, 
+                                      us->ifnum, srb->cmnd, srb->cmd_len);
+
+        /* check the return code for the command */
+        US_DEBUGP("Call to usb_stor_ctrl_transfer() returned %d\n", result);
+
+        /* if we stalled the command, it means command failed */
+        if (result == USB_STOR_XFER_STALLED) {
+                return USB_STOR_TRANSPORT_FAILED;
+        }
+
+        /* Uh oh... serious problem here */
+        if (result != USB_STOR_XFER_GOOD) {
+                return USB_STOR_TRANSPORT_ERROR;
+        }
+
+        /* DATA STAGE */
+        /* transfer the data payload for this command, if one exists*/
+        if (transfer_length) {
+                unsigned int pipe = srb->sc_data_direction == DMA_FROM_DEVICE ? 
+                                us->recv_bulk_pipe : us->send_bulk_pipe;
+                result = usb_stor_bulk_transfer_sg(us, pipe,
+                                        srb->request_buffer, transfer_length,
+                                        srb->use_sg, &srb->resid);
+                US_DEBUGP("CB data stage result is 0x%x\n", result);
+
+                /* if we stalled the data transfer it means command failed */
+                if (result == USB_STOR_XFER_STALLED)
+                        return USB_STOR_TRANSPORT_FAILED;
+                if (result > USB_STOR_XFER_STALLED)
+                        return USB_STOR_TRANSPORT_ERROR;
+        }
+
+        /* STATUS STAGE */
+        /* NOTE: CB does not have a status stage.  Silly, I know.  So
+         * we have to catch this at a higher level.
+         */
+        return USB_STOR_TRANSPORT_GOOD;
+}
+
+/*
+ * Bulk only transport
+ */
+
+/* Determine what the maximum LUN supported is */
+int usb_stor_Bulk_max_lun(struct us_data *us)
+{
+        int result;
+
+        /* issue the command */
+        result = usb_stor_control_msg(us, us->recv_ctrl_pipe,
+                                 US_BULK_GET_MAX_LUN, 
+                                 USB_DIR_IN | USB_TYPE_CLASS | 
+                                 USB_RECIP_INTERFACE,
+                                 0, us->ifnum, us->iobuf, 1, HZ);
+
+        US_DEBUGP("GetMaxLUN command result is %d, data is %d\n", 
+                  result, us->iobuf[0]);
+
+        /* if we have a successful request, return the result */
+        if (result > 0)
+                return us->iobuf[0];
+
+        /* 
+         * Some devices (i.e. Iomega Zip100) need this -- apparently
+         * the bulk pipes get STALLed when the GetMaxLUN request is
+         * processed.   This is, in theory, harmless to all other devices
+         * (regardless of if they stall or not).
+         */
+        if (result == -EPIPE) {
+                usb_stor_clear_halt(us, us->recv_bulk_pipe);
+                usb_stor_clear_halt(us, us->send_bulk_pipe);
+        }
+
+        /*
+         * Some devices don't like GetMaxLUN.  They may STALL the control
+         * pipe, they may return a zero-length result, they may do nothing at
+         * all and timeout, or they may fail in even more bizarrely creative
+         * ways.  In these cases the best approach is to use the default
+         * value: only one LUN.
+         */
+        return 0;
+}
+
+int usb_stor_Bulk_transport(struct scsi_cmnd *srb, struct us_data *us)
+{
+        struct bulk_cb_wrap *bcb = (struct bulk_cb_wrap *) us->iobuf;
+        struct bulk_cs_wrap *bcs = (struct bulk_cs_wrap *) us->iobuf;
+        unsigned int transfer_length = srb->request_bufflen;
+        unsigned int residue;
+        int result;
+        int fake_sense = 0;
+        unsigned int cswlen;
+        unsigned int cbwlen = US_BULK_CB_WRAP_LEN;
+
+        /* Take care of BULK32 devices; set extra byte to 0 */
+        if ( unlikely(us->flags & US_FL_BULK32)) {
+                cbwlen = 32;
+                us->iobuf[31] = 0;
+        }
+
+        /* set up the command wrapper */
+        bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
+        bcb->DataTransferLength = cpu_to_le32(transfer_length);
+        bcb->Flags = srb->sc_data_direction == DMA_FROM_DEVICE ? 1 << 7 : 0;
+        bcb->Tag = srb->serial_number;
+        bcb->Lun = srb->device->lun;
+        if (us->flags & US_FL_SCM_MULT_TARG)
+                bcb->Lun |= srb->device->id << 4;
+        bcb->Length = srb->cmd_len;
+
+        /* copy the command payload */
+        memset(bcb->CDB, 0, sizeof(bcb->CDB));
+        memcpy(bcb->CDB, srb->cmnd, bcb->Length);
+
+        /* send it to out endpoint */
+        US_DEBUGP("Bulk Command S 0x%x T 0x%x L %d F %d Trg %d LUN %d CL %d\n",
+                        le32_to_cpu(bcb->Signature), bcb->Tag,
+                        le32_to_cpu(bcb->DataTransferLength), bcb->Flags,
+                        (bcb->Lun >> 4), (bcb->Lun & 0x0F), 
+                        bcb->Length);
+        result = usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe,
+                                bcb, cbwlen, NULL);
+        US_DEBUGP("Bulk command transfer result=%d\n", result);
+        if (result != USB_STOR_XFER_GOOD)
+                return USB_STOR_TRANSPORT_ERROR;
+
+        /* DATA STAGE */
+        /* send/receive data payload, if there is any */
+
+        /* Some USB-IDE converter chips need a 100us delay between the
+         * command phase and the data phase.  Some devices need a little
+         * more than that, probably because of clock rate inaccuracies. */
+        if (unlikely(us->flags & US_FL_GO_SLOW))
+                udelay(110);
+
+        if (transfer_length) {
+                unsigned int pipe = srb->sc_data_direction == DMA_FROM_DEVICE ? 
+                                us->recv_bulk_pipe : us->send_bulk_pipe;
+                result = usb_stor_bulk_transfer_sg(us, pipe,
+                                        srb->request_buffer, transfer_length,
+                                        srb->use_sg, &srb->resid);
+                US_DEBUGP("Bulk data transfer result 0x%x\n", result);
+                if (result == USB_STOR_XFER_ERROR)
+                        return USB_STOR_TRANSPORT_ERROR;
+
+                /* If the device tried to send back more data than the
+                 * amount requested, the spec requires us to transfer
+                 * the CSW anyway.  Since there's no point retrying the
+                 * the command, we'll return fake sense data indicating
+                 * Illegal Request, Invalid Field in CDB.
+                 */
+                if (result == USB_STOR_XFER_LONG)
+                        fake_sense = 1;
+        }
+
+        /* See flow chart on pg 15 of the Bulk Only Transport spec for
+         * an explanation of how this code works.
+         */
+
+        /* get CSW for device status */
+        US_DEBUGP("Attempting to get CSW...\n");
+        result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
+                                bcs, US_BULK_CS_WRAP_LEN, &cswlen);
+
+        /* Some broken devices add unnecessary zero-length packets to the
+         * end of their data transfers.  Such packets show up as 0-length
+         * CSWs.  If we encounter such a thing, try to read the CSW again.
+         */
+        if (result == USB_STOR_XFER_SHORT && cswlen == 0) {
+                US_DEBUGP("Received 0-length CSW; retrying...\n");
+                result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
+                                bcs, US_BULK_CS_WRAP_LEN, &cswlen);
+        }
+
+        /* did the attempt to read the CSW fail? */
+        if (result == USB_STOR_XFER_STALLED) {
+
+                /* get the status again */
+                US_DEBUGP("Attempting to get CSW (2nd try)...\n");
+                result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
+                                bcs, US_BULK_CS_WRAP_LEN, NULL);
+        }
+
+        /* if we still have a failure at this point, we're in trouble */
+        US_DEBUGP("Bulk status result = %d\n", result);
+        if (result != USB_STOR_XFER_GOOD)
+                return USB_STOR_TRANSPORT_ERROR;
+
+        /* check bulk status */
+        residue = le32_to_cpu(bcs->Residue);
+        US_DEBUGP("Bulk Status S 0x%x T 0x%x R %u Stat 0x%x\n",
+                        le32_to_cpu(bcs->Signature), bcs->Tag, 
+                        residue, bcs->Status);
+        if (bcs->Tag != srb->serial_number || bcs->Status > US_BULK_STAT_PHASE) {
+                US_DEBUGP("Bulk logical error\n");
+                return USB_STOR_TRANSPORT_ERROR;
+        }
+
+        /* Some broken devices report odd signatures, so we do not check them
+         * for validity against the spec. We store the first one we see,
+         * and check subsequent transfers for validity against this signature.
+         */
+        if (!us->bcs_signature) {
+                us->bcs_signature = bcs->Signature;
+                if (us->bcs_signature != cpu_to_le32(US_BULK_CS_SIGN))
+                        US_DEBUGP("Learnt BCS signature 0x%08X\n",
+                                        le32_to_cpu(us->bcs_signature));
+        } else if (bcs->Signature != us->bcs_signature) {
+                US_DEBUGP("Signature mismatch: got %08X, expecting %08X\n",
+                          le32_to_cpu(bcs->Signature),
+                          le32_to_cpu(us->bcs_signature));
+                return USB_STOR_TRANSPORT_ERROR;
+        }
+
+        /* try to compute the actual residue, based on how much data
+         * was really transferred and what the device tells us */
+        if (residue) {
+                if (!(us->flags & US_FL_IGNORE_RESIDUE)) {
+                        residue = min(residue, transfer_length);
+                        srb->resid = max(srb->resid, (int) residue);
+                }
+        }
+
+        /* based on the status code, we report good or bad */
+        switch (bcs->Status) {
+                case US_BULK_STAT_OK:
+                        /* device babbled -- return fake sense data */
+                        if (fake_sense) {
+                                memcpy(srb->sense_buffer, 
+                                       usb_stor_sense_invalidCDB, 
+                                       sizeof(usb_stor_sense_invalidCDB));
+                                return USB_STOR_TRANSPORT_NO_SENSE;
+                        }
+
+                        /* command good -- note that data could be short */
+                        return USB_STOR_TRANSPORT_GOOD;
+
+                case US_BULK_STAT_FAIL:
+                        /* command failed */
+                        return USB_STOR_TRANSPORT_FAILED;
+
+                case US_BULK_STAT_PHASE:
+                        /* phase error -- note that a transport reset will be
+                         * invoked by the invoke_transport() function
+                         */
+                        return USB_STOR_TRANSPORT_ERROR;
+        }
+
+        /* we should never get here, but if we do, we're in trouble */
+        return USB_STOR_TRANSPORT_ERROR;
+}
+
+/***********************************************************************
+ * Reset routines
+ ***********************************************************************/
+
+/* This is the common part of the device reset code.
+ *
+ * It's handy that every transport mechanism uses the control endpoint for
+ * resets.
+ *
+ * Basically, we send a reset with a 20-second timeout, so we don't get
+ * jammed attempting to do the reset.
+ */
+static int usb_stor_reset_common(struct us_data *us,
+                u8 request, u8 requesttype,
+                u16 value, u16 index, void *data, u16 size)
+{
+        int result;
+        int result2;
+        int rc = FAILED;
+
+        /* Let the SCSI layer know we are doing a reset, set the
+         * RESETTING bit, and clear the ABORTING bit so that the reset
+         * may proceed.
+         */
+        scsi_lock(us_to_host(us));
+        usb_stor_report_device_reset(us);
+        set_bit(US_FLIDX_RESETTING, &us->flags);
+        clear_bit(US_FLIDX_ABORTING, &us->flags);
+        scsi_unlock(us_to_host(us));
+
+        /* A 20-second timeout may seem rather long, but a LaCie
+         * StudioDrive USB2 device takes 16+ seconds to get going
+         * following a powerup or USB attach event.
+         */
+        result = usb_stor_control_msg(us, us->send_ctrl_pipe,
+                        request, requesttype, value, index, data, size,
+                        20*HZ);
+        if (result < 0) {
+                US_DEBUGP("Soft reset failed: %d\n", result);
+                goto Done;
+        }
+
+        /* Give the device some time to recover from the reset,
+         * but don't delay disconnect processing. */
+        wait_event_interruptible_timeout(us->delay_wait,
+                        test_bit(US_FLIDX_DISCONNECTING, &us->flags),
+                        HZ*6);
+        if (test_bit(US_FLIDX_DISCONNECTING, &us->flags)) {
+                US_DEBUGP("Reset interrupted by disconnect\n");
+                goto Done;
+        }
+
+        US_DEBUGP("Soft reset: clearing bulk-in endpoint halt\n");
+        result = usb_stor_clear_halt(us, us->recv_bulk_pipe);
+
+        US_DEBUGP("Soft reset: clearing bulk-out endpoint halt\n");
+        result2 = usb_stor_clear_halt(us, us->send_bulk_pipe);
+
+        /* return a result code based on the result of the control message */
+        if (result < 0 || result2 < 0) {
+                US_DEBUGP("Soft reset failed\n");
+                goto Done;
+        }
+        US_DEBUGP("Soft reset done\n");
+        rc = SUCCESS;
+
+  Done:
+        clear_bit(US_FLIDX_RESETTING, &us->flags);
+        return rc;
+}
+
+/* This issues a CB[I] Reset to the device in question
+ */
+#define CB_RESET_CMD_SIZE       12
+
+int usb_stor_CB_reset(struct us_data *us)
+{
+        US_DEBUGP("%s called\n", __FUNCTION__);
+
+        memset(us->iobuf, 0xFF, CB_RESET_CMD_SIZE);
+        us->iobuf[0] = SEND_DIAGNOSTIC;
+        us->iobuf[1] = 4;
+        return usb_stor_reset_common(us, US_CBI_ADSC, 
+                                 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
+                                 0, us->ifnum, us->iobuf, CB_RESET_CMD_SIZE);
+}
+
+/* This issues a Bulk-only Reset to the device in question, including
+ * clearing the subsequent endpoint halts that may occur.
+ */
+int usb_stor_Bulk_reset(struct us_data *us)
+{
+        US_DEBUGP("%s called\n", __FUNCTION__);
+
+        return usb_stor_reset_common(us, US_BULK_RESET_REQUEST, 
+                                 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
+                                 0, us->ifnum, NULL, 0);
+}