[TG3]: Set minimal hw interrupt mitigation.

[linux-2.6/verdex.git] / drivers / usb / storage / shuttle_usbat.c

/* Driver for SCM Microsystems USB-ATAPI cable
 *
 * $Id: shuttle_usbat.c,v 1.17 2002/04/22 03:39:43 mdharm Exp $
 *
 * Current development and maintenance by:
 *   (c) 2000, 2001 Robert Baruch (autophile@starband.net)
 *   (c) 2004, 2005 Daniel Drake <dsd@gentoo.org>
 *
 * Developed with the assistance of:
 *   (c) 2002 Alan Stern <stern@rowland.org>
 *
 * Flash support based on earlier work by:
 *   (c) 2002 Thomas Kreiling <usbdev@sm04.de>
 *
 * Many originally ATAPI devices were slightly modified to meet the USB
 * market by using some kind of translation from ATAPI to USB on the host,
 * and the peripheral would translate from USB back to ATAPI.
 *
 * SCM Microsystems (www.scmmicro.com) makes a device, sold to OEM's only, 
 * which does the USB-to-ATAPI conversion.  By obtaining the data sheet on
 * their device under nondisclosure agreement, I have been able to write
 * this driver for Linux.
 *
 * The chip used in the device can also be used for EPP and ISA translation
 * as well. This driver is only guaranteed to work with the ATAPI
 * translation.
 *
 * See the Kconfig help text for a list of devices known to be supported by
 * 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/sched.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/cdrom.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>

#include "usb.h"
#include "transport.h"
#include "protocol.h"
#include "debug.h"
#include "shuttle_usbat.h"

#define short_pack(LSB,MSB) ( ((u16)(LSB)) | ( ((u16)(MSB))<<8 ) )
#define LSB_of(s) ((s)&0xFF)
#define MSB_of(s) ((s)>>8)

static int transferred = 0;

static int usbat_flash_transport(struct scsi_cmnd * srb, struct us_data *us);
static int usbat_hp8200e_transport(struct scsi_cmnd *srb, struct us_data *us);

/*
 * Convenience function to produce an ATAPI read/write sectors command
 * Use cmd=0x20 for read, cmd=0x30 for write
 */
static void usbat_pack_atapi_sector_cmd(unsigned char *buf,
                                        unsigned char thistime,
                                        u32 sector, unsigned char cmd)
{
        buf[0] = 0;
        buf[1] = thistime;
        buf[2] = sector & 0xFF;
        buf[3] = (sector >>  8) & 0xFF;
        buf[4] = (sector >> 16) & 0xFF;
        buf[5] = 0xE0 | ((sector >> 24) & 0x0F);
        buf[6] = cmd;
}

/*
 * Convenience function to get the device type (flash or hp8200)
 */
static int usbat_get_device_type(struct us_data *us)
{
        return ((struct usbat_info*)us->extra)->devicetype;
}

/*
 * Read a register from the device
 */
static int usbat_read(struct us_data *us,
                      unsigned char access,
                      unsigned char reg,
                      unsigned char *content)
{
        return usb_stor_ctrl_transfer(us,
                us->recv_ctrl_pipe,
                access | USBAT_CMD_READ_REG,
                0xC0,
                (u16)reg,
                0,
                content,
                1);
}

/*
 * Write to a register on the device
 */
static int usbat_write(struct us_data *us,
                       unsigned char access,
                       unsigned char reg,
                       unsigned char content)
{
        return usb_stor_ctrl_transfer(us,
                us->send_ctrl_pipe,
                access | USBAT_CMD_WRITE_REG,
                0x40,
                short_pack(reg, content),
                0,
                NULL,
                0);
}

/*
 * Convenience function to perform a bulk read
 */
static int usbat_bulk_read(struct us_data *us,
                                                         unsigned char *data,
                                                         unsigned int len)
{
        if (len == 0)
                return USB_STOR_XFER_GOOD;

        US_DEBUGP("usbat_bulk_read: len = %d\n", len);
        return usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe, data, len, NULL);
}

/*
 * Convenience function to perform a bulk write
 */
static int usbat_bulk_write(struct us_data *us,
                                                        unsigned char *data,
                                                        unsigned int len)
{
        if (len == 0)
                return USB_STOR_XFER_GOOD;

        US_DEBUGP("usbat_bulk_write:  len = %d\n", len);
        return usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe, data, len, NULL);
}

/*
 * Some USBAT-specific commands can only be executed over a command transport
 * This transport allows one (len=8) or two (len=16) vendor-specific commands
 * to be executed.
 */
static int usbat_execute_command(struct us_data *us,
                                                                 unsigned char *commands,
                                                                 unsigned int len)
{
        return usb_stor_ctrl_transfer(us, us->send_ctrl_pipe,
                                                                  USBAT_CMD_EXEC_CMD, 0x40, 0, 0,
                                                                  commands, len);
}

/*
 * Read the status register
 */
static int usbat_get_status(struct us_data *us, unsigned char *status)
{
        int rc;
        rc = usbat_read(us, USBAT_ATA, USBAT_ATA_STATUS, status);

        US_DEBUGP("usbat_get_status: 0x%02X\n", (unsigned short) (*status));
        return rc;
}

/*
 * Check the device status
 */
static int usbat_check_status(struct us_data *us)
{
        unsigned char *reply = us->iobuf;
        int rc;

        if (!us)
                return USB_STOR_TRANSPORT_ERROR;

        rc = usbat_get_status(us, reply);
        if (rc != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_FAILED;

        if (*reply & 0x01 && *reply != 0x51) // error/check condition (0x51 is ok)
                return USB_STOR_TRANSPORT_FAILED;

        if (*reply & 0x20) // device fault
                return USB_STOR_TRANSPORT_FAILED;

        return USB_STOR_TRANSPORT_GOOD;
}

/*
 * Stores critical information in internal registers in prepartion for the execution
 * of a conditional usbat_read_blocks or usbat_write_blocks call.
 */
static int usbat_set_shuttle_features(struct us_data *us,
                                      unsigned char external_trigger,
                                      unsigned char epp_control,
                                      unsigned char mask_byte,
                                      unsigned char test_pattern,
                                      unsigned char subcountH,
                                      unsigned char subcountL)
{
        unsigned char *command = us->iobuf;

        command[0] = 0x40;
        command[1] = USBAT_CMD_SET_FEAT;

        // The only bit relevant to ATA access is bit 6
        // which defines 8 bit data access (set) or 16 bit (unset)
        command[2] = epp_control;

        // If FCQ is set in the qualifier (defined in R/W cmd), then bits U0, U1,
        // ET1 and ET2 define an external event to be checked for on event of a
        // _read_blocks or _write_blocks operation. The read/write will not take
        // place unless the defined trigger signal is active.
        command[3] = external_trigger;

        // The resultant byte of the mask operation (see mask_byte) is compared for
        // equivalence with this test pattern. If equal, the read/write will take
        // place.
        command[4] = test_pattern;

        // This value is logically ANDed with the status register field specified
        // in the read/write command.
        command[5] = mask_byte;

        // If ALQ is set in the qualifier, this field contains the address of the
        // registers where the byte count should be read for transferring the data.
        // If ALQ is not set, then this field contains the number of bytes to be
        // transferred.
        command[6] = subcountL;
        command[7] = subcountH;

        return usbat_execute_command(us, command, 8);
}

/*
 * Block, waiting for an ATA device to become not busy or to report
 * an error condition.
 */
static int usbat_wait_not_busy(struct us_data *us, int minutes)
{
        int i;
        int result;
        unsigned char *status = us->iobuf;

        /* Synchronizing cache on a CDR could take a heck of a long time,
         * but probably not more than 10 minutes or so. On the other hand,
         * doing a full blank on a CDRW at speed 1 will take about 75
         * minutes!
         */

        for (i=0; i<1200+minutes*60; i++) {

                result = usbat_get_status(us, status);

                if (result!=USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;
                if (*status & 0x01) { // check condition
                        result = usbat_read(us, USBAT_ATA, 0x10, status);
                        return USB_STOR_TRANSPORT_FAILED;
                }
                if (*status & 0x20) // device fault
                        return USB_STOR_TRANSPORT_FAILED;

                if ((*status & 0x80)==0x00) { // not busy
                        US_DEBUGP("Waited not busy for %d steps\n", i);
                        return USB_STOR_TRANSPORT_GOOD;
                }

                if (i<500)
                        msleep(10); // 5 seconds
                else if (i<700)
                        msleep(50); // 10 seconds
                else if (i<1200)
                        msleep(100); // 50 seconds
                else
                        msleep(1000); // X minutes
        }

        US_DEBUGP("Waited not busy for %d minutes, timing out.\n",
                minutes);
        return USB_STOR_TRANSPORT_FAILED;
}

/*
 * Read block data from the data register
 */
static int usbat_read_block(struct us_data *us,
                            unsigned char *content,
                            unsigned short len)
{
        int result;
        unsigned char *command = us->iobuf;

        if (!len)
                return USB_STOR_TRANSPORT_GOOD;

        command[0] = 0xC0;
        command[1] = USBAT_ATA | USBAT_CMD_READ_BLOCK;
        command[2] = USBAT_ATA_DATA;
        command[3] = 0;
        command[4] = 0;
        command[5] = 0;
        command[6] = LSB_of(len);
        command[7] = MSB_of(len);

        result = usbat_execute_command(us, command, 8);
        if (result != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        result = usbat_bulk_read(us, content, len);
        return (result == USB_STOR_XFER_GOOD ?
                        USB_STOR_TRANSPORT_GOOD : USB_STOR_TRANSPORT_ERROR);
}

/*
 * Write block data via the data register
 */
static int usbat_write_block(struct us_data *us,
                             unsigned char access,
                             unsigned char *content,
                             unsigned short len,
                             int minutes)
{
        int result;
        unsigned char *command = us->iobuf;

        if (!len)
                return USB_STOR_TRANSPORT_GOOD;

        command[0] = 0x40;
        command[1] = access | USBAT_CMD_WRITE_BLOCK;
        command[2] = USBAT_ATA_DATA;
        command[3] = 0;
        command[4] = 0;
        command[5] = 0;
        command[6] = LSB_of(len);
        command[7] = MSB_of(len);

        result = usbat_execute_command(us, command, 8);

        if (result != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        result = usbat_bulk_write(us, content, len);
        if (result != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        return usbat_wait_not_busy(us, minutes);
}

/*
 * Process read and write requests
 */
static int usbat_hp8200e_rw_block_test(struct us_data *us,
                                       unsigned char access,
                                       unsigned char *registers,
                                       unsigned char *data_out,
                                       unsigned short num_registers,
                                       unsigned char data_reg,
                                       unsigned char status_reg,
                                       unsigned char timeout,
                                       unsigned char qualifier,
                                       int direction,
                                       unsigned char *content,
                                       unsigned short len,
                                       int use_sg,
                                       int minutes)
{
        int result;
        unsigned int pipe = (direction == DMA_FROM_DEVICE) ?
                        us->recv_bulk_pipe : us->send_bulk_pipe;

        unsigned char *command = us->iobuf;
        int i, j;
        int cmdlen;
        unsigned char *data = us->iobuf;
        unsigned char *status = us->iobuf;

        BUG_ON(num_registers > US_IOBUF_SIZE/2);

        for (i=0; i<20; i++) {

                /*
                 * The first time we send the full command, which consists
                 * of downloading the SCSI command followed by downloading
                 * the data via a write-and-test.  Any other time we only
                 * send the command to download the data -- the SCSI command
                 * is still 'active' in some sense in the device.
                 * 
                 * We're only going to try sending the data 10 times. After
                 * that, we just return a failure.
                 */

                if (i==0) {
                        cmdlen = 16;
                        // Write to multiple registers
                        // Not really sure the 0x07, 0x17, 0xfc, 0xe7 is necessary here,
                        // but that's what came out of the trace every single time.
                        command[0] = 0x40;
                        command[1] = access | USBAT_CMD_WRITE_REGS;
                        command[2] = 0x07;
                        command[3] = 0x17;
                        command[4] = 0xFC;
                        command[5] = 0xE7;
                        command[6] = LSB_of(num_registers*2);
                        command[7] = MSB_of(num_registers*2);
                } else
                        cmdlen = 8;

                // Conditionally read or write blocks
                command[cmdlen-8] = (direction==DMA_TO_DEVICE ? 0x40 : 0xC0);
                command[cmdlen-7] = access |
                                (direction==DMA_TO_DEVICE ?
                                 USBAT_CMD_COND_WRITE_BLOCK : USBAT_CMD_COND_READ_BLOCK);
                command[cmdlen-6] = data_reg;
                command[cmdlen-5] = status_reg;
                command[cmdlen-4] = timeout;
                command[cmdlen-3] = qualifier;
                command[cmdlen-2] = LSB_of(len);
                command[cmdlen-1] = MSB_of(len);

                result = usbat_execute_command(us, command, cmdlen);

                if (result != USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;

                if (i==0) {

                        for (j=0; j<num_registers; j++) {
                                data[j<<1] = registers[j];
                                data[1+(j<<1)] = data_out[j];
                        }

                        result = usbat_bulk_write(us, data, num_registers*2);
                        if (result != USB_STOR_XFER_GOOD)
                                return USB_STOR_TRANSPORT_ERROR;

                }


                //US_DEBUGP("Transfer %s %d bytes, sg buffers %d\n",
                //      direction == DMA_TO_DEVICE ? "out" : "in",
                //      len, use_sg);

                result = usb_stor_bulk_transfer_sg(us,
                        pipe, content, len, use_sg, NULL);

                /*
                 * If we get a stall on the bulk download, we'll retry
                 * the bulk download -- but not the SCSI command because
                 * in some sense the SCSI command is still 'active' and
                 * waiting for the data. Don't ask me why this should be;
                 * I'm only following what the Windoze driver did.
                 *
                 * Note that a stall for the test-and-read/write command means
                 * that the test failed. In this case we're testing to make
                 * sure that the device is error-free
                 * (i.e. bit 0 -- CHK -- of status is 0). The most likely
                 * hypothesis is that the USBAT chip somehow knows what
                 * the device will accept, but doesn't give the device any
                 * data until all data is received. Thus, the device would
                 * still be waiting for the first byte of data if a stall
                 * occurs, even if the stall implies that some data was
                 * transferred.
                 */

                if (result == USB_STOR_XFER_SHORT ||
                                result == USB_STOR_XFER_STALLED) {

                        /*
                         * If we're reading and we stalled, then clear
                         * the bulk output pipe only the first time.
                         */

                        if (direction==DMA_FROM_DEVICE && i==0) {
                                if (usb_stor_clear_halt(us,
                                                us->send_bulk_pipe) < 0)
                                        return USB_STOR_TRANSPORT_ERROR;
                        }

                        /*
                         * Read status: is the device angry, or just busy?
                         */

                        result = usbat_read(us, USBAT_ATA, 
                                direction==DMA_TO_DEVICE ?
                                        USBAT_ATA_STATUS : USBAT_ATA_ALTSTATUS,
                                status);

                        if (result!=USB_STOR_XFER_GOOD)
                                return USB_STOR_TRANSPORT_ERROR;
                        if (*status & 0x01) // check condition
                                return USB_STOR_TRANSPORT_FAILED;
                        if (*status & 0x20) // device fault
                                return USB_STOR_TRANSPORT_FAILED;

                        US_DEBUGP("Redoing %s\n",
                          direction==DMA_TO_DEVICE ? "write" : "read");

                } else if (result != USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;
                else
                        return usbat_wait_not_busy(us, minutes);

        }

        US_DEBUGP("Bummer! %s bulk data 20 times failed.\n",
                direction==DMA_TO_DEVICE ? "Writing" : "Reading");

        return USB_STOR_TRANSPORT_FAILED;
}

/*
 * Write to multiple registers:
 * Allows us to write specific data to any registers. The data to be written
 * gets packed in this sequence: reg0, data0, reg1, data1, ..., regN, dataN
 * which gets sent through bulk out.
 * Not designed for large transfers of data!
 */
static int usbat_multiple_write(struct us_data *us,
                                unsigned char *registers,
                                unsigned char *data_out,
                                unsigned short num_registers)
{
        int i, result;
        unsigned char *data = us->iobuf;
        unsigned char *command = us->iobuf;

        BUG_ON(num_registers > US_IOBUF_SIZE/2);

        // Write to multiple registers, ATA access
        command[0] = 0x40;
        command[1] = USBAT_ATA | USBAT_CMD_WRITE_REGS;

        // No relevance
        command[2] = 0;
        command[3] = 0;
        command[4] = 0;
        command[5] = 0;

        // Number of bytes to be transferred (incl. addresses and data)
        command[6] = LSB_of(num_registers*2);
        command[7] = MSB_of(num_registers*2);

        // The setup command
        result = usbat_execute_command(us, command, 8);
        if (result != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        // Create the reg/data, reg/data sequence
        for (i=0; i<num_registers; i++) {
                data[i<<1] = registers[i];
                data[1+(i<<1)] = data_out[i];
        }

        // Send the data
        result = usbat_bulk_write(us, data, num_registers*2);
        if (result != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        if (usbat_get_device_type(us) == USBAT_DEV_HP8200)
                return usbat_wait_not_busy(us, 0);
        else
                return USB_STOR_TRANSPORT_GOOD;
}

/*
 * Conditionally read blocks from device:
 * Allows us to read blocks from a specific data register, based upon the
 * condition that a status register can be successfully masked with a status
 * qualifier. If this condition is not initially met, the read will wait
 * up until a maximum amount of time has elapsed, as specified by timeout.
 * The read will start when the condition is met, otherwise the command aborts.
 *
 * The qualifier defined here is not the value that is masked, it defines
 * conditions for the write to take place. The actual masked qualifier (and
 * other related details) are defined beforehand with _set_shuttle_features().
 */
static int usbat_read_blocks(struct us_data *us,
                                                         unsigned char *buffer,
                                                         int len)
{
        int result;
        unsigned char *command = us->iobuf;

        command[0] = 0xC0;
        command[1] = USBAT_ATA | USBAT_CMD_COND_READ_BLOCK;
        command[2] = USBAT_ATA_DATA;
        command[3] = USBAT_ATA_STATUS;
        command[4] = 0xFD; // Timeout (ms);
        command[5] = USBAT_QUAL_FCQ;
        command[6] = LSB_of(len);
        command[7] = MSB_of(len);

        // Multiple block read setup command
        result = usbat_execute_command(us, command, 8);
        if (result != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_FAILED;
        
        // Read the blocks we just asked for
        result = usbat_bulk_read(us, buffer, len);
        if (result != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_FAILED;

        return USB_STOR_TRANSPORT_GOOD;
}

/*
 * Conditionally write blocks to device:
 * Allows us to write blocks to a specific data register, based upon the
 * condition that a status register can be successfully masked with a status
 * qualifier. If this condition is not initially met, the write will wait
 * up until a maximum amount of time has elapsed, as specified by timeout.
 * The read will start when the condition is met, otherwise the command aborts.
 *
 * The qualifier defined here is not the value that is masked, it defines
 * conditions for the write to take place. The actual masked qualifier (and
 * other related details) are defined beforehand with _set_shuttle_features().
 */
static int usbat_write_blocks(struct us_data *us,
                                                          unsigned char *buffer,
                                                          int len)
{
        int result;
        unsigned char *command = us->iobuf;

        command[0] = 0x40;
        command[1] = USBAT_ATA | USBAT_CMD_COND_WRITE_BLOCK;
        command[2] = USBAT_ATA_DATA;
        command[3] = USBAT_ATA_STATUS;
        command[4] = 0xFD; // Timeout (ms)
        command[5] = USBAT_QUAL_FCQ;
        command[6] = LSB_of(len);
        command[7] = MSB_of(len);

        // Multiple block write setup command
        result = usbat_execute_command(us, command, 8);
        if (result != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_FAILED;
        
        // Write the data
        result = usbat_bulk_write(us, buffer, len);
        if (result != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_FAILED;

        return USB_STOR_TRANSPORT_GOOD;
}

/*
 * Read the User IO register
 */
static int usbat_read_user_io(struct us_data *us, unsigned char *data_flags)
{
        int result;

        result = usb_stor_ctrl_transfer(us,
                us->recv_ctrl_pipe,
                USBAT_CMD_UIO,
                0xC0,
                0,
                0,
                data_flags,
                USBAT_UIO_READ);

        US_DEBUGP("usbat_read_user_io: UIO register reads %02X\n", (unsigned short) (*data_flags));

        return result;
}

/*
 * Write to the User IO register
 */
static int usbat_write_user_io(struct us_data *us,
                               unsigned char enable_flags,
                               unsigned char data_flags)
{
        return usb_stor_ctrl_transfer(us,
                us->send_ctrl_pipe,
                USBAT_CMD_UIO,
                0x40,
                short_pack(enable_flags, data_flags),
                0,
                NULL,
                USBAT_UIO_WRITE);
}

/*
 * Reset the device
 * Often needed on media change.
 */
static int usbat_device_reset(struct us_data *us)
{
        int rc;

        // Reset peripheral, enable peripheral control signals
        // (bring reset signal up)
        rc = usbat_write_user_io(us,
                                                         USBAT_UIO_DRVRST | USBAT_UIO_OE1 | USBAT_UIO_OE0,
                                                         USBAT_UIO_EPAD | USBAT_UIO_1);
        if (rc != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;
                        
        // Enable peripheral control signals
        // (bring reset signal down)
        rc = usbat_write_user_io(us,
                                                         USBAT_UIO_OE1  | USBAT_UIO_OE0,
                                                         USBAT_UIO_EPAD | USBAT_UIO_1);
        if (rc != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        return USB_STOR_TRANSPORT_GOOD;
}

/*
 * Enable card detect
 */
static int usbat_device_enable_cdt(struct us_data *us)
{
        int rc;

        // Enable peripheral control signals and card detect
        rc = usbat_write_user_io(us,
                                                         USBAT_UIO_ACKD | USBAT_UIO_OE1  | USBAT_UIO_OE0,
                                                         USBAT_UIO_EPAD | USBAT_UIO_1);
        if (rc != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        return USB_STOR_TRANSPORT_GOOD;
}

/*
 * Determine if media is present.
 */
static int usbat_flash_check_media_present(unsigned char *uio)
{
        if (*uio & USBAT_UIO_UI0) {
                US_DEBUGP("usbat_flash_check_media_present: no media detected\n");
                return USBAT_FLASH_MEDIA_NONE;
        }

        return USBAT_FLASH_MEDIA_CF;
}

/*
 * Determine if media has changed since last operation
 */
static int usbat_flash_check_media_changed(unsigned char *uio)
{
        if (*uio & USBAT_UIO_0) {
                US_DEBUGP("usbat_flash_check_media_changed: media change detected\n");
                return USBAT_FLASH_MEDIA_CHANGED;
        }

        return USBAT_FLASH_MEDIA_SAME;
}

/*
 * Check for media change / no media and handle the situation appropriately
 */
static int usbat_flash_check_media(struct us_data *us,
                                   struct usbat_info *info)
{
        int rc;
        unsigned char *uio = us->iobuf;

        rc = usbat_read_user_io(us, uio);
        if (rc != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        // Check for media existence
        rc = usbat_flash_check_media_present(uio);
        if (rc == USBAT_FLASH_MEDIA_NONE) {
                info->sense_key = 0x02;
                info->sense_asc = 0x3A;
                info->sense_ascq = 0x00;
                return USB_STOR_TRANSPORT_FAILED;
        }

        // Check for media change
        rc = usbat_flash_check_media_changed(uio);
        if (rc == USBAT_FLASH_MEDIA_CHANGED) {

                // Reset and re-enable card detect
                rc = usbat_device_reset(us);
                if (rc != USB_STOR_TRANSPORT_GOOD)
                        return rc;
                rc = usbat_device_enable_cdt(us);
                if (rc != USB_STOR_TRANSPORT_GOOD)
                        return rc;

                msleep(50);

                rc = usbat_read_user_io(us, uio);
                if (rc != USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;
                
                info->sense_key = UNIT_ATTENTION;
                info->sense_asc = 0x28;
                info->sense_ascq = 0x00;
                return USB_STOR_TRANSPORT_FAILED;
        }

        return USB_STOR_TRANSPORT_GOOD;
}

/*
 * Determine whether we are controlling a flash-based reader/writer,
 * or a HP8200-based CD drive.
 * Sets transport functions as appropriate.
 */
static int usbat_identify_device(struct us_data *us,
                                 struct usbat_info *info)
{
        int rc;
        unsigned char status;

        if (!us || !info)
                return USB_STOR_TRANSPORT_ERROR;

        rc = usbat_device_reset(us);
        if (rc != USB_STOR_TRANSPORT_GOOD)
                return rc;

        /*
         * By examining the device signature after a reset, we can identify
         * whether the device supports the ATAPI packet interface.
         * The flash-devices do not support this, whereas the HP CDRW's obviously
         * do.
         *
         * This method is not ideal, but works because no other devices have been
         * produced based on the USBAT/USBAT02.
         *
         * Section 9.1 of the ATAPI-4 spec states (amongst other things) that
         * after a device reset, a Cylinder low of 0x14 indicates that the device
         * does support packet commands.
         */
        rc = usbat_read(us, USBAT_ATA, USBAT_ATA_LBA_ME, &status);
        if (rc != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        US_DEBUGP("usbat_identify_device: Cylinder low is %02X\n", status);

        if (status == 0x14) {
                // Device is HP 8200
                US_DEBUGP("usbat_identify_device: Detected HP8200 CDRW\n");
                info->devicetype = USBAT_DEV_HP8200;
        } else {
                // Device is a CompactFlash reader/writer
                US_DEBUGP("usbat_identify_device: Detected Flash reader/writer\n");
                info->devicetype = USBAT_DEV_FLASH;
        }

        return USB_STOR_TRANSPORT_GOOD;
}

/*
 * Set the transport function based on the device type
 */
static int usbat_set_transport(struct us_data *us,
                               struct usbat_info *info)
{
        int rc;

        if (!info->devicetype) {
                rc = usbat_identify_device(us, info);
                if (rc != USB_STOR_TRANSPORT_GOOD) {
                        US_DEBUGP("usbat_set_transport: Could not identify device\n");
                        return 1;
                }
        }

        if (usbat_get_device_type(us) == USBAT_DEV_HP8200)
                us->transport = usbat_hp8200e_transport;
        else if (usbat_get_device_type(us) == USBAT_DEV_FLASH)
                us->transport = usbat_flash_transport;

        return 0;
}

/*
 * Read the media capacity
 */
static int usbat_flash_get_sector_count(struct us_data *us,
                                        struct usbat_info *info)
{
        unsigned char registers[3] = {
                USBAT_ATA_SECCNT,
                USBAT_ATA_DEVICE,
                USBAT_ATA_CMD,
        };
        unsigned char  command[3] = { 0x01, 0xA0, 0xEC };
        unsigned char *reply;
        unsigned char status;
        int rc;

        if (!us || !info)
                return USB_STOR_TRANSPORT_ERROR;

        reply = kmalloc(512, GFP_NOIO);
        if (!reply)
                return USB_STOR_TRANSPORT_ERROR;

        // ATAPI command : IDENTIFY DEVICE
        rc = usbat_multiple_write(us, registers, command, 3);
        if (rc != USB_STOR_XFER_GOOD) {
                US_DEBUGP("usbat_flash_get_sector_count: Gah! identify_device failed\n");
                rc = USB_STOR_TRANSPORT_ERROR;
                goto leave;
        }

        // Read device status
        if (usbat_get_status(us, &status) != USB_STOR_XFER_GOOD) {
                rc = USB_STOR_TRANSPORT_ERROR;
                goto leave;
        }

        msleep(100);

        // Read the device identification data
        rc = usbat_read_block(us, reply, 512);
        if (rc != USB_STOR_TRANSPORT_GOOD)
                goto leave;

        info->sectors = ((u32)(reply[117]) << 24) |
                ((u32)(reply[116]) << 16) |
                ((u32)(reply[115]) <<  8) |
                ((u32)(reply[114])      );

        rc = USB_STOR_TRANSPORT_GOOD;

 leave:
        kfree(reply);
        return rc;
}

/*
 * Read data from device
 */
static int usbat_flash_read_data(struct us_data *us,
                                                                 struct usbat_info *info,
                                                                 u32 sector,
                                                                 u32 sectors)
{
        unsigned char registers[7] = {
                USBAT_ATA_FEATURES,
                USBAT_ATA_SECCNT,
                USBAT_ATA_SECNUM,
                USBAT_ATA_LBA_ME,
                USBAT_ATA_LBA_HI,
                USBAT_ATA_DEVICE,
                USBAT_ATA_STATUS,
        };
        unsigned char command[7];
        unsigned char *buffer;
        unsigned char  thistime;
        unsigned int totallen, alloclen;
        int len, result;
        unsigned int sg_idx = 0, sg_offset = 0;

        result = usbat_flash_check_media(us, info);
        if (result != USB_STOR_TRANSPORT_GOOD)
                return result;

        // we're working in LBA mode.  according to the ATA spec,
        // we can support up to 28-bit addressing.  I don't know if Jumpshot
        // supports beyond 24-bit addressing.  It's kind of hard to test
        // since it requires > 8GB CF card.

        if (sector > 0x0FFFFFFF)
                return USB_STOR_TRANSPORT_ERROR;

        totallen = sectors * info->ssize;

        // Since we don't read more than 64 KB at a time, we have to create
        // a bounce buffer and move the data a piece at a time between the
        // bounce buffer and the actual transfer buffer.

        alloclen = min(totallen, 65536u);
        buffer = kmalloc(alloclen, GFP_NOIO);
        if (buffer == NULL)
                return USB_STOR_TRANSPORT_ERROR;

        do {
                // loop, never allocate or transfer more than 64k at once
                // (min(128k, 255*info->ssize) is the real limit)
                len = min(totallen, alloclen);
                thistime = (len / info->ssize) & 0xff;
 
                // ATAPI command 0x20 (READ SECTORS)
                usbat_pack_atapi_sector_cmd(command, thistime, sector, 0x20);

                // Write/execute ATAPI read command
                result = usbat_multiple_write(us, registers, command, 7);
                if (result != USB_STOR_TRANSPORT_GOOD)
                        goto leave;

                // Read the data we just requested
                result = usbat_read_blocks(us, buffer, len);
                if (result != USB_STOR_TRANSPORT_GOOD)
                        goto leave;
         
                US_DEBUGP("usbat_flash_read_data:  %d bytes\n", len);
        
                // Store the data in the transfer buffer
                usb_stor_access_xfer_buf(buffer, len, us->srb,
                                         &sg_idx, &sg_offset, TO_XFER_BUF);

                sector += thistime;
                totallen -= len;
        } while (totallen > 0);

        kfree(buffer);
        return USB_STOR_TRANSPORT_GOOD;

leave:
        kfree(buffer);
        return USB_STOR_TRANSPORT_ERROR;
}

/*
 * Write data to device
 */
static int usbat_flash_write_data(struct us_data *us,
                                                                  struct usbat_info *info,
                                                                  u32 sector,
                                                                  u32 sectors)
{
        unsigned char registers[7] = {
                USBAT_ATA_FEATURES,
                USBAT_ATA_SECCNT,
                USBAT_ATA_SECNUM,
                USBAT_ATA_LBA_ME,
                USBAT_ATA_LBA_HI,
                USBAT_ATA_DEVICE,
                USBAT_ATA_STATUS,
        };
        unsigned char command[7];
        unsigned char *buffer;
        unsigned char  thistime;
        unsigned int totallen, alloclen;
        int len, result;
        unsigned int sg_idx = 0, sg_offset = 0;

        result = usbat_flash_check_media(us, info);
        if (result != USB_STOR_TRANSPORT_GOOD)
                return result;

        // we're working in LBA mode.  according to the ATA spec,
        // we can support up to 28-bit addressing.  I don't know if Jumpshot
        // supports beyond 24-bit addressing.  It's kind of hard to test
        // since it requires > 8GB CF card.

        if (sector > 0x0FFFFFFF)
                return USB_STOR_TRANSPORT_ERROR;

        totallen = sectors * info->ssize;

        // Since we don't write more than 64 KB at a time, we have to create
        // a bounce buffer and move the data a piece at a time between the
        // bounce buffer and the actual transfer buffer.

        alloclen = min(totallen, 65536u);
        buffer = kmalloc(alloclen, GFP_NOIO);
        if (buffer == NULL)
                return USB_STOR_TRANSPORT_ERROR;

        do {
                // loop, never allocate or transfer more than 64k at once
                // (min(128k, 255*info->ssize) is the real limit)
                len = min(totallen, alloclen);
                thistime = (len / info->ssize) & 0xff;

                // Get the data from the transfer buffer
                usb_stor_access_xfer_buf(buffer, len, us->srb,
                                         &sg_idx, &sg_offset, FROM_XFER_BUF);

                // ATAPI command 0x30 (WRITE SECTORS)
                usbat_pack_atapi_sector_cmd(command, thistime, sector, 0x30);           

                // Write/execute ATAPI write command
                result = usbat_multiple_write(us, registers, command, 7);
                if (result != USB_STOR_TRANSPORT_GOOD)
                        goto leave;

                // Write the data
                result = usbat_write_blocks(us, buffer, len);
                if (result != USB_STOR_TRANSPORT_GOOD)
                        goto leave;

                sector += thistime;
                totallen -= len;
        } while (totallen > 0);

        kfree(buffer);
        return result;

leave:
        kfree(buffer);
        return USB_STOR_TRANSPORT_ERROR;
}

/*
 * Squeeze a potentially huge (> 65535 byte) read10 command into
 * a little ( <= 65535 byte) ATAPI pipe
 */
static int usbat_hp8200e_handle_read10(struct us_data *us,
                                       unsigned char *registers,
                                       unsigned char *data,
                                       struct scsi_cmnd *srb)
{
        int result = USB_STOR_TRANSPORT_GOOD;
        unsigned char *buffer;
        unsigned int len;
        unsigned int sector;
        unsigned int sg_segment = 0;
        unsigned int sg_offset = 0;

        US_DEBUGP("handle_read10: transfersize %d\n",
                srb->transfersize);

        if (srb->request_bufflen < 0x10000) {

                result = usbat_hp8200e_rw_block_test(us, USBAT_ATA, 
                        registers, data, 19,
                        USBAT_ATA_DATA, USBAT_ATA_STATUS, 0xFD,
                        (USBAT_QUAL_FCQ | USBAT_QUAL_ALQ),
                        DMA_FROM_DEVICE,
                        srb->request_buffer, 
                        srb->request_bufflen, srb->use_sg, 1);

                return result;
        }

        /*
         * Since we're requesting more data than we can handle in
         * a single read command (max is 64k-1), we will perform
         * multiple reads, but each read must be in multiples of
         * a sector.  Luckily the sector size is in srb->transfersize
         * (see linux/drivers/scsi/sr.c).
         */

        if (data[7+0] == GPCMD_READ_CD) {
                len = short_pack(data[7+9], data[7+8]);
                len <<= 16;
                len |= data[7+7];
                US_DEBUGP("handle_read10: GPCMD_READ_CD: len %d\n", len);
                srb->transfersize = srb->request_bufflen/len;
        }

        if (!srb->transfersize)  {
                srb->transfersize = 2048; /* A guess */
                US_DEBUGP("handle_read10: transfersize 0, forcing %d\n",
                        srb->transfersize);
        }

        // Since we only read in one block at a time, we have to create
        // a bounce buffer and move the data a piece at a time between the
        // bounce buffer and the actual transfer buffer.

        len = (65535/srb->transfersize) * srb->transfersize;
        US_DEBUGP("Max read is %d bytes\n", len);
        len = min(len, srb->request_bufflen);
        buffer = kmalloc(len, GFP_NOIO);
        if (buffer == NULL) // bloody hell!
                return USB_STOR_TRANSPORT_FAILED;
        sector = short_pack(data[7+3], data[7+2]);
        sector <<= 16;
        sector |= short_pack(data[7+5], data[7+4]);
        transferred = 0;

        sg_segment = 0; // for keeping track of where we are in
        sg_offset = 0;  // the scatter/gather list

        while (transferred != srb->request_bufflen) {

                if (len > srb->request_bufflen - transferred)
                        len = srb->request_bufflen - transferred;

                data[3] = len&0xFF;       // (cylL) = expected length (L)
                data[4] = (len>>8)&0xFF;  // (cylH) = expected length (H)

                // Fix up the SCSI command sector and num sectors

                data[7+2] = MSB_of(sector>>16); // SCSI command sector
                data[7+3] = LSB_of(sector>>16);
                data[7+4] = MSB_of(sector&0xFFFF);
                data[7+5] = LSB_of(sector&0xFFFF);
                if (data[7+0] == GPCMD_READ_CD)
                        data[7+6] = 0;
                data[7+7] = MSB_of(len / srb->transfersize); // SCSI command
                data[7+8] = LSB_of(len / srb->transfersize); // num sectors

                result = usbat_hp8200e_rw_block_test(us, USBAT_ATA, 
                        registers, data, 19,
                        USBAT_ATA_DATA, USBAT_ATA_STATUS, 0xFD, 
                        (USBAT_QUAL_FCQ | USBAT_QUAL_ALQ),
                        DMA_FROM_DEVICE,
                        buffer,
                        len, 0, 1);

                if (result != USB_STOR_TRANSPORT_GOOD)
                        break;

                // Store the data in the transfer buffer
                usb_stor_access_xfer_buf(buffer, len, srb,
                                 &sg_segment, &sg_offset, TO_XFER_BUF);

                // Update the amount transferred and the sector number

                transferred += len;
                sector += len / srb->transfersize;

        } // while transferred != srb->request_bufflen

        kfree(buffer);
        return result;
}

static int usbat_select_and_test_registers(struct us_data *us)
{
        int selector;
        unsigned char *status = us->iobuf;
        unsigned char max_selector = 0xB0;
        if (usbat_get_device_type(us) == USBAT_DEV_FLASH)
                max_selector = 0xA0;

        // try device = master, then device = slave.

        for (selector = 0xA0; selector <= max_selector; selector += 0x10) {

                if (usbat_get_device_type(us) == USBAT_DEV_HP8200 &&
                        usbat_write(us, USBAT_ATA, USBAT_ATA_DEVICE, selector) != 
                                USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;

                if (usbat_read(us, USBAT_ATA, USBAT_ATA_STATUS, status) != 
                                USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;

                if (usbat_read(us, USBAT_ATA, USBAT_ATA_DEVICE, status) != 
                                USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;

                if (usbat_read(us, USBAT_ATA, USBAT_ATA_LBA_ME, status) != 
                                USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;

                if (usbat_read(us, USBAT_ATA, USBAT_ATA_LBA_HI, status) != 
                                USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;

                if (usbat_write(us, USBAT_ATA, USBAT_ATA_LBA_ME, 0x55) != 
                                USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;

                if (usbat_write(us, USBAT_ATA, USBAT_ATA_LBA_HI, 0xAA) != 
                                USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;

                if (usbat_read(us, USBAT_ATA, USBAT_ATA_LBA_ME, status) != 
                                USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;

                if (usbat_read(us, USBAT_ATA, USBAT_ATA_LBA_ME, status) != 
                                USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;
        }

        return USB_STOR_TRANSPORT_GOOD;
}

/*
 * Initialize the USBAT processor and the storage device
 */
int init_usbat(struct us_data *us)
{
        int rc;
        struct usbat_info *info;
        unsigned char subcountH = USBAT_ATA_LBA_HI;
        unsigned char subcountL = USBAT_ATA_LBA_ME;
        unsigned char *status = us->iobuf;

        us->extra = kmalloc(sizeof(struct usbat_info), GFP_NOIO);
        if (!us->extra) {
                US_DEBUGP("init_usbat: Gah! Can't allocate storage for usbat info struct!\n");
                return 1;
        }
        memset(us->extra, 0, sizeof(struct usbat_info));
        info = (struct usbat_info *) (us->extra);

        // Enable peripheral control signals
        rc = usbat_write_user_io(us,
                                 USBAT_UIO_OE1 | USBAT_UIO_OE0,
                                 USBAT_UIO_EPAD | USBAT_UIO_1);
        if (rc != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        US_DEBUGP("INIT 1\n");

        msleep(2000);

        rc = usbat_read_user_io(us, status);
        if (rc != USB_STOR_TRANSPORT_GOOD)
                return rc;

        US_DEBUGP("INIT 2\n");

        rc = usbat_read_user_io(us, status);
        if (rc != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        rc = usbat_read_user_io(us, status);
        if (rc != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        US_DEBUGP("INIT 3\n");

        // At this point, we need to detect which device we are using
        if (usbat_set_transport(us, info))
                return USB_STOR_TRANSPORT_ERROR;

        US_DEBUGP("INIT 4\n");

        if (usbat_get_device_type(us) == USBAT_DEV_HP8200) {
                msleep(250);

                // Write 0x80 to ISA port 0x3F
                rc = usbat_write(us, USBAT_ISA, 0x3F, 0x80);
                if (rc != USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;

                US_DEBUGP("INIT 5\n");

                // Read ISA port 0x27
                rc = usbat_read(us, USBAT_ISA, 0x27, status);
                if (rc != USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;

                US_DEBUGP("INIT 6\n");

                rc = usbat_read_user_io(us, status);
                if (rc != USB_STOR_XFER_GOOD)
                        return USB_STOR_TRANSPORT_ERROR;

                US_DEBUGP("INIT 7\n");
        }

        rc = usbat_select_and_test_registers(us);
        if (rc != USB_STOR_TRANSPORT_GOOD)
                return rc;

        US_DEBUGP("INIT 8\n");

        rc = usbat_read_user_io(us, status);
        if (rc != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        US_DEBUGP("INIT 9\n");

        // Enable peripheral control signals and card detect
        rc = usbat_device_enable_cdt(us);
        if (rc != USB_STOR_TRANSPORT_GOOD)
                return rc;

        US_DEBUGP("INIT 10\n");

        rc = usbat_read_user_io(us, status);
        if (rc != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        US_DEBUGP("INIT 11\n");

        msleep(1400);

        rc = usbat_read_user_io(us, status);
        if (rc != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        US_DEBUGP("INIT 12\n");

        rc = usbat_select_and_test_registers(us);
        if (rc != USB_STOR_TRANSPORT_GOOD)
                return rc;

        US_DEBUGP("INIT 13\n");

        if (usbat_get_device_type(us) == USBAT_DEV_FLASH) { 
                subcountH = 0x02;
                subcountL = 0x00;
        }
        rc = usbat_set_shuttle_features(us, (USBAT_FEAT_ETEN | USBAT_FEAT_ET2 | USBAT_FEAT_ET1),
                                                                        0x00, 0x88, 0x08, subcountH, subcountL);
        if (rc != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;

        US_DEBUGP("INIT 14\n");

        return USB_STOR_TRANSPORT_GOOD;
}

/*
 * Transport for the HP 8200e
 */
static int usbat_hp8200e_transport(struct scsi_cmnd *srb, struct us_data *us)
{
        int result;
        unsigned char *status = us->iobuf;
        unsigned char registers[32];
        unsigned char data[32];
        unsigned int len;
        int i;
        char string[64];

        len = srb->request_bufflen;

        /* Send A0 (ATA PACKET COMMAND).
           Note: I guess we're never going to get any of the ATA
           commands... just ATA Packet Commands.
         */

        registers[0] = USBAT_ATA_FEATURES;
        registers[1] = USBAT_ATA_SECCNT;
        registers[2] = USBAT_ATA_SECNUM;
        registers[3] = USBAT_ATA_LBA_ME;
        registers[4] = USBAT_ATA_LBA_HI;
        registers[5] = USBAT_ATA_DEVICE;
        registers[6] = USBAT_ATA_CMD;
        data[0] = 0x00;
        data[1] = 0x00;
        data[2] = 0x00;
        data[3] = len&0xFF;             // (cylL) = expected length (L)
        data[4] = (len>>8)&0xFF;        // (cylH) = expected length (H)
        data[5] = 0xB0;                 // (device sel) = slave
        data[6] = 0xA0;                 // (command) = ATA PACKET COMMAND

        for (i=7; i<19; i++) {
                registers[i] = 0x10;
                data[i] = (i-7 >= srb->cmd_len) ? 0 : srb->cmnd[i-7];
        }

        result = usbat_get_status(us, status);
        US_DEBUGP("Status = %02X\n", *status);
        if (result != USB_STOR_XFER_GOOD)
                return USB_STOR_TRANSPORT_ERROR;
        if (srb->cmnd[0] == TEST_UNIT_READY)
                transferred = 0;

        if (srb->sc_data_direction == DMA_TO_DEVICE) {

                result = usbat_hp8200e_rw_block_test(us, USBAT_ATA, 
                        registers, data, 19,
                        USBAT_ATA_DATA, USBAT_ATA_STATUS, 0xFD,
                        (USBAT_QUAL_FCQ | USBAT_QUAL_ALQ),
                        DMA_TO_DEVICE,
                        srb->request_buffer, 
                        len, srb->use_sg, 10);

                if (result == USB_STOR_TRANSPORT_GOOD) {
                        transferred += len;
                        US_DEBUGP("Wrote %08X bytes\n", transferred);
                }

                return result;

        } else if (srb->cmnd[0] == READ_10 ||
                   srb->cmnd[0] == GPCMD_READ_CD) {

                return usbat_hp8200e_handle_read10(us, registers, data, srb);

        }

        if (len > 0xFFFF) {
                US_DEBUGP("Error: len = %08X... what do I do now?\n",
                        len);
                return USB_STOR_TRANSPORT_ERROR;
        }

        if ( (result = usbat_multiple_write(us, 
                        registers, data, 7)) != USB_STOR_TRANSPORT_GOOD) {
                return result;
        }

        // Write the 12-byte command header.

        // If the command is BLANK then set the timer for 75 minutes.
        // Otherwise set it for 10 minutes.

        // NOTE: THE 8200 DOCUMENTATION STATES THAT BLANKING A CDRW
        // AT SPEED 4 IS UNRELIABLE!!!

        if ( (result = usbat_write_block(us, 
                        USBAT_ATA, srb->cmnd, 12,
                        srb->cmnd[0]==GPCMD_BLANK ? 75 : 10)) !=
                                USB_STOR_TRANSPORT_GOOD) {
                return result;
        }

        // If there is response data to be read in 
        // then do it here.

        if (len != 0 && (srb->sc_data_direction == DMA_FROM_DEVICE)) {

                // How many bytes to read in? Check cylL register

                if (usbat_read(us, USBAT_ATA, USBAT_ATA_LBA_ME, status) != 
                        USB_STOR_XFER_GOOD) {
                        return USB_STOR_TRANSPORT_ERROR;
                }

                if (len > 0xFF) { // need to read cylH also
                        len = *status;
                        if (usbat_read(us, USBAT_ATA, USBAT_ATA_LBA_HI, status) !=
                                    USB_STOR_XFER_GOOD) {
                                return USB_STOR_TRANSPORT_ERROR;
                        }
                        len += ((unsigned int) *status)<<8;
                }
                else
                        len = *status;


                result = usbat_read_block(us, srb->request_buffer, len);

                /* Debug-print the first 32 bytes of the transfer */

                if (!srb->use_sg) {
                        string[0] = 0;
                        for (i=0; i<len && i<32; i++) {
                                sprintf(string+strlen(string), "%02X ",
                                  ((unsigned char *)srb->request_buffer)[i]);
                                if ((i%16)==15) {
                                        US_DEBUGP("%s\n", string);
                                        string[0] = 0;
                                }
                        }
                        if (string[0]!=0)
                                US_DEBUGP("%s\n", string);
                }
        }

        return result;
}

/*
 * Transport for USBAT02-based CompactFlash and similar storage devices
 */
static int usbat_flash_transport(struct scsi_cmnd * srb, struct us_data *us)
{
        int rc;
        struct usbat_info *info = (struct usbat_info *) (us->extra);
        unsigned long block, blocks;
        unsigned char *ptr = us->iobuf;
        static unsigned char inquiry_response[36] = {
                0x00, 0x80, 0x00, 0x01, 0x1F, 0x00, 0x00, 0x00
        };

        if (srb->cmnd[0] == INQUIRY) {
                US_DEBUGP("usbat_flash_transport: INQUIRY. Returning bogus response.\n");
                memcpy(ptr, inquiry_response, sizeof(inquiry_response));
                fill_inquiry_response(us, ptr, 36);
                return USB_STOR_TRANSPORT_GOOD;
        }

        if (srb->cmnd[0] == READ_CAPACITY) {
                rc = usbat_flash_check_media(us, info);
                if (rc != USB_STOR_TRANSPORT_GOOD)
                        return rc;

                rc = usbat_flash_get_sector_count(us, info);
                if (rc != USB_STOR_TRANSPORT_GOOD)
                        return rc;

                info->ssize = 0x200;  // hard coded 512 byte sectors as per ATA spec
                US_DEBUGP("usbat_flash_transport: READ_CAPACITY: %ld sectors, %ld bytes per sector\n",
                          info->sectors, info->ssize);

                // build the reply
                // note: must return the sector number of the last sector,
                // *not* the total number of sectors
                ((__be32 *) ptr)[0] = cpu_to_be32(info->sectors - 1);
                ((__be32 *) ptr)[1] = cpu_to_be32(info->ssize);
                usb_stor_set_xfer_buf(ptr, 8, srb);

                return USB_STOR_TRANSPORT_GOOD;
        }

        if (srb->cmnd[0] == MODE_SELECT_10) {
                US_DEBUGP("usbat_flash_transport:  Gah! MODE_SELECT_10.\n");
                return USB_STOR_TRANSPORT_ERROR;
        }

        if (srb->cmnd[0] == READ_10) {
                block = ((u32)(srb->cmnd[2]) << 24) | ((u32)(srb->cmnd[3]) << 16) |
                                ((u32)(srb->cmnd[4]) <<  8) | ((u32)(srb->cmnd[5]));

                blocks = ((u32)(srb->cmnd[7]) << 8) | ((u32)(srb->cmnd[8]));

                US_DEBUGP("usbat_flash_transport:  READ_10: read block 0x%04lx  count %ld\n", block, blocks);
                return usbat_flash_read_data(us, info, block, blocks);
        }

        if (srb->cmnd[0] == READ_12) {
                // I don't think we'll ever see a READ_12 but support it anyway...
                block = ((u32)(srb->cmnd[2]) << 24) | ((u32)(srb->cmnd[3]) << 16) |
                        ((u32)(srb->cmnd[4]) <<  8) | ((u32)(srb->cmnd[5]));

                blocks = ((u32)(srb->cmnd[6]) << 24) | ((u32)(srb->cmnd[7]) << 16) |
                         ((u32)(srb->cmnd[8]) <<  8) | ((u32)(srb->cmnd[9]));

                US_DEBUGP("usbat_flash_transport: READ_12: read block 0x%04lx  count %ld\n", block, blocks);
                return usbat_flash_read_data(us, info, block, blocks);
        }

        if (srb->cmnd[0] == WRITE_10) {
                block = ((u32)(srb->cmnd[2]) << 24) | ((u32)(srb->cmnd[3]) << 16) |
                        ((u32)(srb->cmnd[4]) <<  8) | ((u32)(srb->cmnd[5]));

                blocks = ((u32)(srb->cmnd[7]) << 8) | ((u32)(srb->cmnd[8]));

                US_DEBUGP("usbat_flash_transport: WRITE_10: write block 0x%04lx  count %ld\n", block, blocks);
                return usbat_flash_write_data(us, info, block, blocks);
        }

        if (srb->cmnd[0] == WRITE_12) {
                // I don't think we'll ever see a WRITE_12 but support it anyway...
                block = ((u32)(srb->cmnd[2]) << 24) | ((u32)(srb->cmnd[3]) << 16) |
                        ((u32)(srb->cmnd[4]) <<  8) | ((u32)(srb->cmnd[5]));

                blocks = ((u32)(srb->cmnd[6]) << 24) | ((u32)(srb->cmnd[7]) << 16) |
                         ((u32)(srb->cmnd[8]) <<  8) | ((u32)(srb->cmnd[9]));

                US_DEBUGP("usbat_flash_transport: WRITE_12: write block 0x%04lx  count %ld\n", block, blocks);
                return usbat_flash_write_data(us, info, block, blocks);
        }


        if (srb->cmnd[0] == TEST_UNIT_READY) {
                US_DEBUGP("usbat_flash_transport: TEST_UNIT_READY.\n");

                rc = usbat_flash_check_media(us, info);
                if (rc != USB_STOR_TRANSPORT_GOOD)
                        return rc;

                return usbat_check_status(us);
        }

        if (srb->cmnd[0] == REQUEST_SENSE) {
                US_DEBUGP("usbat_flash_transport: REQUEST_SENSE.\n");

                memset(ptr, 0, 18);
                ptr[0] = 0xF0;
                ptr[2] = info->sense_key;
                ptr[7] = 11;
                ptr[12] = info->sense_asc;
                ptr[13] = info->sense_ascq;
                usb_stor_set_xfer_buf(ptr, 18, srb);

                return USB_STOR_TRANSPORT_GOOD;
        }

        if (srb->cmnd[0] == ALLOW_MEDIUM_REMOVAL) {
                // sure.  whatever.  not like we can stop the user from popping
                // the media out of the device (no locking doors, etc)
                return USB_STOR_TRANSPORT_GOOD;
        }

        US_DEBUGP("usbat_flash_transport: Gah! Unknown command: %d (0x%x)\n",
                          srb->cmnd[0], srb->cmnd[0]);
        info->sense_key = 0x05;
        info->sense_asc = 0x20;
        info->sense_ascq = 0x00;
        return USB_STOR_TRANSPORT_FAILED;
}

/*
 * Default transport function. Attempts to detect which transport function
 * should be called, makes it the new default, and calls it.
 *
 * This function should never be called. Our usbat_init() function detects the
 * device type and changes the us->transport ptr to the transport function
 * relevant to the device.
 * However, we'll support this impossible(?) case anyway.
 */
int usbat_transport(struct scsi_cmnd *srb, struct us_data *us)
{
        struct usbat_info *info = (struct usbat_info*) (us->extra);

        if (usbat_set_transport(us, info))
                return USB_STOR_TRANSPORT_ERROR;

        return us->transport(srb, us);  
}