sddr55.c

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/* Driver for SanDisk SDDR-55 SmartMedia reader
 *
 * SDDR55 driver v0.1:
 *
 * First release
 *
 * Current development and maintenance by:
 *   (c) 2002 Simon Munton
 *
 * 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/jiffies.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/slab.h>

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

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

MODULE_DESCRIPTION("Driver for SanDisk SDDR-55 SmartMedia reader");
MODULE_AUTHOR("Simon Munton");
MODULE_LICENSE("GPL");

/*
 * The table of devices
 */
#define UNUSUAL_DEV(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax, \
            vendorName, productName, useProtocol, useTransport, \
            initFunction, flags) \
{ USB_DEVICE_VER(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax), \
  .driver_info = (flags) }

static struct usb_device_id sddr55_usb_ids[] = {
#   include "unusual_sddr55.h"
    { }     /* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, sddr55_usb_ids);

#undef UNUSUAL_DEV

/*
 * The flags table
 */
#define UNUSUAL_DEV(idVendor, idProduct, bcdDeviceMin, bcdDeviceMax, \
            vendor_name, product_name, use_protocol, use_transport, \
            init_function, Flags) \
{ \
    .vendorName = vendor_name,  \
    .productName = product_name,    \
    .useProtocol = use_protocol,    \
    .useTransport = use_transport,  \
    .initFunction = init_function,  \
}

static struct us_unusual_dev sddr55_unusual_dev_list[] = {
#   include "unusual_sddr55.h"
    { }     /* Terminating entry */
};

#undef UNUSUAL_DEV


#define short_pack(lsb,msb) ( ((u16)(lsb)) | ( ((u16)(msb))<<8 ) )
#define LSB_of(s) ((s)&0xFF)
#define MSB_of(s) ((s)>>8)
#define PAGESIZE  512

#define set_sense_info(sk, asc, ascq)   \
    do {                \
    info->sense_data[2] = sk;   \
    info->sense_data[12] = asc; \
    info->sense_data[13] = ascq;    \
    } while (0)


struct sddr55_card_info {
    unsigned long   capacity;   /* Size of card in bytes */
    int     max_log_blks;   /* maximum number of logical blocks */
    int     pageshift;  /* log2 of pagesize */
    int     smallpageshift; /* 1 if pagesize == 256 */
    int     blocksize;  /* Size of block in pages */
    int     blockshift; /* log2 of blocksize */
    int     blockmask;  /* 2^blockshift - 1 */
    int     read_only;  /* non zero if card is write protected */
    int     force_read_only;    /* non zero if we find a map error*/
    int     *lba_to_pba;    /* logical to physical map */
    int     *pba_to_lba;    /* physical to logical map */
    int     fatal_error;    /* set if we detect something nasty */
    unsigned long   last_access;    /* number of jiffies since we last talked to device */
    unsigned char   sense_data[18];
};


#define NOT_ALLOCATED       0xffffffff
#define BAD_BLOCK       0xffff
#define CIS_BLOCK       0x400
#define UNUSED_BLOCK        0x3ff

static int
sddr55_bulk_transport(struct us_data *us, int direction,
              unsigned char *data, unsigned int len) {
    struct sddr55_card_info *info = (struct sddr55_card_info *)us->extra;
    unsigned int pipe = (direction == DMA_FROM_DEVICE) ?
            us->recv_bulk_pipe : us->send_bulk_pipe;

    if (!len)
        return USB_STOR_XFER_GOOD;
    info->last_access = jiffies;
    return usb_stor_bulk_transfer_buf(us, pipe, data, len, NULL);
}

/* check if card inserted, if there is, update read_only status
 * return non zero if no card
 */

static int sddr55_status(struct us_data *us)
{
    int result;
    unsigned char *command = us->iobuf;
    unsigned char *status = us->iobuf;
    struct sddr55_card_info *info = (struct sddr55_card_info *)us->extra;

    /* send command */
    memset(command, 0, 8);
    command[5] = 0xB0;
    command[7] = 0x80;
    result = sddr55_bulk_transport(us,
        DMA_TO_DEVICE, command, 8);

    US_DEBUGP("Result for send_command in status %d\n",
        result);

    if (result != USB_STOR_XFER_GOOD) {
        set_sense_info (4, 0, 0);   /* hardware error */
        return USB_STOR_TRANSPORT_ERROR;
    }

    result = sddr55_bulk_transport(us,
        DMA_FROM_DEVICE, status,    4);

    /* expect to get short transfer if no card fitted */
    if (result == USB_STOR_XFER_SHORT || result == USB_STOR_XFER_STALLED) {
        /* had a short transfer, no card inserted, free map memory */
        kfree(info->lba_to_pba);
        kfree(info->pba_to_lba);
        info->lba_to_pba = NULL;
        info->pba_to_lba = NULL;

        info->fatal_error = 0;
        info->force_read_only = 0;

        set_sense_info (2, 0x3a, 0);    /* not ready, medium not present */
        return USB_STOR_TRANSPORT_FAILED;
    }

    if (result != USB_STOR_XFER_GOOD) {
        set_sense_info (4, 0, 0);   /* hardware error */
        return USB_STOR_TRANSPORT_FAILED;
    }
    
    /* check write protect status */
    info->read_only = (status[0] & 0x20);

    /* now read status */
    result = sddr55_bulk_transport(us,
        DMA_FROM_DEVICE, status,    2);

    if (result != USB_STOR_XFER_GOOD) {
        set_sense_info (4, 0, 0);   /* hardware error */
    }

    return (result == USB_STOR_XFER_GOOD ?
            USB_STOR_TRANSPORT_GOOD : USB_STOR_TRANSPORT_FAILED);
}


static int sddr55_read_data(struct us_data *us,
        unsigned int lba,
        unsigned int page,
        unsigned short sectors) {

    int result = USB_STOR_TRANSPORT_GOOD;
    unsigned char *command = us->iobuf;
    unsigned char *status = us->iobuf;
    struct sddr55_card_info *info = (struct sddr55_card_info *)us->extra;
    unsigned char *buffer;

    unsigned int pba;
    unsigned long address;

    unsigned short pages;
    unsigned int len, offset;
    struct scatterlist *sg;

    // 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 = min((unsigned int) sectors, (unsigned int) info->blocksize >>
            info->smallpageshift) * PAGESIZE;
    buffer = kmalloc(len, GFP_NOIO);
    if (buffer == NULL)
        return USB_STOR_TRANSPORT_ERROR; /* out of memory */
    offset = 0;
    sg = NULL;

    while (sectors>0) {

        /* have we got to end? */
        if (lba >= info->max_log_blks)
            break;

        pba = info->lba_to_pba[lba];

        // Read as many sectors as possible in this block

        pages = min((unsigned int) sectors << info->smallpageshift,
                info->blocksize - page);
        len = pages << info->pageshift;

        US_DEBUGP("Read %02X pages, from PBA %04X"
            " (LBA %04X) page %02X\n",
            pages, pba, lba, page);

        if (pba == NOT_ALLOCATED) {
            /* no pba for this lba, fill with zeroes */
            memset (buffer, 0, len);
        } else {

            address = (pba << info->blockshift) + page;

            command[0] = 0;
            command[1] = LSB_of(address>>16);
            command[2] = LSB_of(address>>8);
            command[3] = LSB_of(address);

            command[4] = 0;
            command[5] = 0xB0;
            command[6] = LSB_of(pages << (1 - info->smallpageshift));
            command[7] = 0x85;

            /* send command */
            result = sddr55_bulk_transport(us,
                DMA_TO_DEVICE, command, 8);

            US_DEBUGP("Result for send_command in read_data %d\n",
                result);

            if (result != USB_STOR_XFER_GOOD) {
                result = USB_STOR_TRANSPORT_ERROR;
                goto leave;
            }

            /* read data */
            result = sddr55_bulk_transport(us,
                DMA_FROM_DEVICE, buffer, len);

            if (result != USB_STOR_XFER_GOOD) {
                result = USB_STOR_TRANSPORT_ERROR;
                goto leave;
            }

            /* now read status */
            result = sddr55_bulk_transport(us,
                DMA_FROM_DEVICE, status, 2);

            if (result != USB_STOR_XFER_GOOD) {
                result = USB_STOR_TRANSPORT_ERROR;
                goto leave;
            }

            /* check status for error */
            if (status[0] == 0xff && status[1] == 0x4) {
                set_sense_info (3, 0x11, 0);
                result = USB_STOR_TRANSPORT_FAILED;
                goto leave;
            }
        }

        // Store the data in the transfer buffer
        usb_stor_access_xfer_buf(buffer, len, us->srb,
                &sg, &offset, TO_XFER_BUF);

        page = 0;
        lba++;
        sectors -= pages >> info->smallpageshift;
    }

    result = USB_STOR_TRANSPORT_GOOD;

leave:
    kfree(buffer);

    return result;
}

static int sddr55_write_data(struct us_data *us,
        unsigned int lba,
        unsigned int page,
        unsigned short sectors) {

    int result = USB_STOR_TRANSPORT_GOOD;
    unsigned char *command = us->iobuf;
    unsigned char *status = us->iobuf;
    struct sddr55_card_info *info = (struct sddr55_card_info *)us->extra;
    unsigned char *buffer;

    unsigned int pba;
    unsigned int new_pba;
    unsigned long address;

    unsigned short pages;
    int i;
    unsigned int len, offset;
    struct scatterlist *sg;

    /* check if we are allowed to write */
    if (info->read_only || info->force_read_only) {
        set_sense_info (7, 0x27, 0);    /* read only */
        return USB_STOR_TRANSPORT_FAILED;
    }

    // Since we only write 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 = min((unsigned int) sectors, (unsigned int) info->blocksize >>
            info->smallpageshift) * PAGESIZE;
    buffer = kmalloc(len, GFP_NOIO);
    if (buffer == NULL)
        return USB_STOR_TRANSPORT_ERROR;
    offset = 0;
    sg = NULL;

    while (sectors > 0) {

        /* have we got to end? */
        if (lba >= info->max_log_blks)
            break;

        pba = info->lba_to_pba[lba];

        // Write as many sectors as possible in this block

        pages = min((unsigned int) sectors << info->smallpageshift,
                info->blocksize - page);
        len = pages << info->pageshift;

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

        US_DEBUGP("Write %02X pages, to PBA %04X"
            " (LBA %04X) page %02X\n",
            pages, pba, lba, page);
            
        command[4] = 0;

        if (pba == NOT_ALLOCATED) {
            /* no pba allocated for this lba, find a free pba to use */

            int max_pba = (info->max_log_blks / 250 ) * 256;
            int found_count = 0;
            int found_pba = -1;

            /* set pba to first block in zone lba is in */
            pba = (lba / 1000) * 1024;

            US_DEBUGP("No PBA for LBA %04X\n",lba);

            if (max_pba > 1024)
                max_pba = 1024;

            /*
             * Scan through the map looking for an unused block
             * leave 16 unused blocks at start (or as many as
             * possible) since the sddr55 seems to reuse a used
             * block when it shouldn't if we don't leave space.
             */
            for (i = 0; i < max_pba; i++, pba++) {
                if (info->pba_to_lba[pba] == UNUSED_BLOCK) {
                    found_pba = pba;
                    if (found_count++ > 16)
                        break;
                }
            }

            pba = found_pba;

            if (pba == -1) {
                /* oh dear */
                US_DEBUGP("Couldn't find unallocated block\n");

                set_sense_info (3, 0x31, 0);    /* medium error */
                result = USB_STOR_TRANSPORT_FAILED;
                goto leave;
            }

            US_DEBUGP("Allocating PBA %04X for LBA %04X\n", pba, lba);

            /* set writing to unallocated block flag */
            command[4] = 0x40;
        }

        address = (pba << info->blockshift) + page;

        command[1] = LSB_of(address>>16);
        command[2] = LSB_of(address>>8); 
        command[3] = LSB_of(address);

        /* set the lba into the command, modulo 1000 */
        command[0] = LSB_of(lba % 1000);
        command[6] = MSB_of(lba % 1000);

        command[4] |= LSB_of(pages >> info->smallpageshift);
        command[5] = 0xB0;
        command[7] = 0x86;

        /* send command */
        result = sddr55_bulk_transport(us,
            DMA_TO_DEVICE, command, 8);

        if (result != USB_STOR_XFER_GOOD) {
            US_DEBUGP("Result for send_command in write_data %d\n",
            result);

            /* set_sense_info is superfluous here? */
            set_sense_info (3, 0x3, 0);/* peripheral write error */
            result = USB_STOR_TRANSPORT_FAILED;
            goto leave;
        }

        /* send the data */
        result = sddr55_bulk_transport(us,
            DMA_TO_DEVICE, buffer, len);

        if (result != USB_STOR_XFER_GOOD) {
            US_DEBUGP("Result for send_data in write_data %d\n",
                  result);

            /* set_sense_info is superfluous here? */
            set_sense_info (3, 0x3, 0);/* peripheral write error */
            result = USB_STOR_TRANSPORT_FAILED;
            goto leave;
        }

        /* now read status */
        result = sddr55_bulk_transport(us, DMA_FROM_DEVICE, status, 6);

        if (result != USB_STOR_XFER_GOOD) {
            US_DEBUGP("Result for get_status in write_data %d\n",
                  result);

            /* set_sense_info is superfluous here? */
            set_sense_info (3, 0x3, 0);/* peripheral write error */
            result = USB_STOR_TRANSPORT_FAILED;
            goto leave;
        }

        new_pba = (status[3] + (status[4] << 8) + (status[5] << 16))
                          >> info->blockshift;

        /* check status for error */
        if (status[0] == 0xff && status[1] == 0x4) {
            info->pba_to_lba[new_pba] = BAD_BLOCK;

            set_sense_info (3, 0x0c, 0);
            result = USB_STOR_TRANSPORT_FAILED;
            goto leave;
        }

        US_DEBUGP("Updating maps for LBA %04X: old PBA %04X, new PBA %04X\n",
            lba, pba, new_pba);

        /* update the lba<->pba maps, note new_pba might be the same as pba */
        info->lba_to_pba[lba] = new_pba;
        info->pba_to_lba[pba] = UNUSED_BLOCK;

        /* check that new_pba wasn't already being used */
        if (info->pba_to_lba[new_pba] != UNUSED_BLOCK) {
            printk(KERN_ERR "sddr55 error: new PBA %04X already in use for LBA %04X\n",
                new_pba, info->pba_to_lba[new_pba]);
            info->fatal_error = 1;
            set_sense_info (3, 0x31, 0);
            result = USB_STOR_TRANSPORT_FAILED;
            goto leave;
        }

        /* update the pba<->lba maps for new_pba */
        info->pba_to_lba[new_pba] = lba % 1000;

        page = 0;
        lba++;
        sectors -= pages >> info->smallpageshift;
    }
    result = USB_STOR_TRANSPORT_GOOD;

 leave:
    kfree(buffer);
    return result;
}

static int sddr55_read_deviceID(struct us_data *us,
        unsigned char *manufacturerID,
        unsigned char *deviceID) {

    int result;
    unsigned char *command = us->iobuf;
    unsigned char *content = us->iobuf;

    memset(command, 0, 8);
    command[5] = 0xB0;
    command[7] = 0x84;
    result = sddr55_bulk_transport(us, DMA_TO_DEVICE, command, 8);

    US_DEBUGP("Result of send_control for device ID is %d\n",
        result);

    if (result != USB_STOR_XFER_GOOD)
        return USB_STOR_TRANSPORT_ERROR;

    result = sddr55_bulk_transport(us,
        DMA_FROM_DEVICE, content, 4);

    if (result != USB_STOR_XFER_GOOD)
        return USB_STOR_TRANSPORT_ERROR;

    *manufacturerID = content[0];
    *deviceID = content[1];

    if (content[0] != 0xff) {
            result = sddr55_bulk_transport(us,
            DMA_FROM_DEVICE, content, 2);
    }

    return USB_STOR_TRANSPORT_GOOD;
}


static int sddr55_reset(struct us_data *us)
{
    return 0;
}


static unsigned long sddr55_get_capacity(struct us_data *us) {

    unsigned char uninitialized_var(manufacturerID);
    unsigned char uninitialized_var(deviceID);
    int result;
    struct sddr55_card_info *info = (struct sddr55_card_info *)us->extra;

    US_DEBUGP("Reading capacity...\n");

    result = sddr55_read_deviceID(us,
        &manufacturerID,
        &deviceID);

    US_DEBUGP("Result of read_deviceID is %d\n",
        result);

    if (result != USB_STOR_XFER_GOOD)
        return 0;

    US_DEBUGP("Device ID = %02X\n", deviceID);
    US_DEBUGP("Manuf  ID = %02X\n", manufacturerID);

    info->pageshift = 9;
    info->smallpageshift = 0;
    info->blocksize = 16;
    info->blockshift = 4;
    info->blockmask = 15;

    switch (deviceID) {

    case 0x6e: // 1MB
    case 0xe8:
    case 0xec:
        info->pageshift = 8;
        info->smallpageshift = 1;
        return 0x00100000;

    case 0xea: // 2MB
    case 0x64:
        info->pageshift = 8;
        info->smallpageshift = 1;
    case 0x5d: // 5d is a ROM card with pagesize 512.
        return 0x00200000;

    case 0xe3: // 4MB
    case 0xe5:
    case 0x6b:
    case 0xd5:
        return 0x00400000;

    case 0xe6: // 8MB
    case 0xd6:
        return 0x00800000;

    case 0x73: // 16MB
        info->blocksize = 32;
        info->blockshift = 5;
        info->blockmask = 31;
        return 0x01000000;

    case 0x75: // 32MB
        info->blocksize = 32;
        info->blockshift = 5;
        info->blockmask = 31;
        return 0x02000000;

    case 0x76: // 64MB
        info->blocksize = 32;
        info->blockshift = 5;
        info->blockmask = 31;
        return 0x04000000;

    case 0x79: // 128MB
        info->blocksize = 32;
        info->blockshift = 5;
        info->blockmask = 31;
        return 0x08000000;

    default: // unknown
        return 0;

    }
}

static int sddr55_read_map(struct us_data *us) {

    struct sddr55_card_info *info = (struct sddr55_card_info *)(us->extra);
    int numblocks;
    unsigned char *buffer;
    unsigned char *command = us->iobuf;
    int i;
    unsigned short lba;
    unsigned short max_lba;
    int result;

    if (!info->capacity)
        return -1;

    numblocks = info->capacity >> (info->blockshift + info->pageshift);
    
    buffer = kmalloc( numblocks * 2, GFP_NOIO );
    
    if (!buffer)
        return -1;

    memset(command, 0, 8);
    command[5] = 0xB0;
    command[6] = numblocks * 2 / 256;
    command[7] = 0x8A;

    result = sddr55_bulk_transport(us, DMA_TO_DEVICE, command, 8);

    if ( result != USB_STOR_XFER_GOOD) {
        kfree (buffer);
        return -1;
    }

    result = sddr55_bulk_transport(us, DMA_FROM_DEVICE, buffer, numblocks * 2);

    if ( result != USB_STOR_XFER_GOOD) {
        kfree (buffer);
        return -1;
    }

    result = sddr55_bulk_transport(us, DMA_FROM_DEVICE, command, 2);

    if ( result != USB_STOR_XFER_GOOD) {
        kfree (buffer);
        return -1;
    }

    kfree(info->lba_to_pba);
    kfree(info->pba_to_lba);
    info->lba_to_pba = kmalloc(numblocks*sizeof(int), GFP_NOIO);
    info->pba_to_lba = kmalloc(numblocks*sizeof(int), GFP_NOIO);

    if (info->lba_to_pba == NULL || info->pba_to_lba == NULL) {
        kfree(info->lba_to_pba);
        kfree(info->pba_to_lba);
        info->lba_to_pba = NULL;
        info->pba_to_lba = NULL;
        kfree(buffer);
        return -1;
    }

    memset(info->lba_to_pba, 0xff, numblocks*sizeof(int));
    memset(info->pba_to_lba, 0xff, numblocks*sizeof(int));

    /* set maximum lba */
    max_lba = info->max_log_blks;
    if (max_lba > 1000)
        max_lba = 1000;

    // Each block is 64 bytes of control data, so block i is located in
    // scatterlist block i*64/128k = i*(2^6)*(2^-17) = i*(2^-11)

    for (i=0; i<numblocks; i++) {
        int zone = i / 1024;

        lba = short_pack(buffer[i * 2], buffer[i * 2 + 1]);

            /* Every 1024 physical blocks ("zone"), the LBA numbers
             * go back to zero, but are within a higher
             * block of LBA's. Also, there is a maximum of
             * 1000 LBA's per zone. In other words, in PBA
             * 1024-2047 you will find LBA 0-999 which are
             * really LBA 1000-1999. Yes, this wastes 24
             * physical blocks per zone. Go figure. 
             * These devices can have blocks go bad, so there
             * are 24 spare blocks to use when blocks do go bad.
             */

            /* SDDR55 returns 0xffff for a bad block, and 0x400 for the 
             * CIS block. (Is this true for cards 8MB or less??)
             * Record these in the physical to logical map
             */ 

        info->pba_to_lba[i] = lba;

        if (lba >= max_lba) {
            continue;
        }
        
        if (info->lba_to_pba[lba + zone * 1000] != NOT_ALLOCATED &&
            !info->force_read_only) {
            printk(KERN_WARNING
                   "sddr55: map inconsistency at LBA %04X\n",
                   lba + zone * 1000);
            info->force_read_only = 1;
        }

        if (lba<0x10 || (lba>=0x3E0 && lba<0x3EF))
            US_DEBUGP("LBA %04X <-> PBA %04X\n", lba, i);

        info->lba_to_pba[lba + zone * 1000] = i;
    }

    kfree(buffer);
    return 0;
}


static void sddr55_card_info_destructor(void *extra) {
    struct sddr55_card_info *info = (struct sddr55_card_info *)extra;

    if (!extra)
        return;

    kfree(info->lba_to_pba);
    kfree(info->pba_to_lba);
}


/*
 * Transport for the Sandisk SDDR-55
 */
static int sddr55_transport(struct scsi_cmnd *srb, struct us_data *us)
{
    int result;
    static unsigned char inquiry_response[8] = {
        0x00, 0x80, 0x00, 0x02, 0x1F, 0x00, 0x00, 0x00
    };
    // write-protected for now, no block descriptor support
    static unsigned char mode_page_01[20] = {
        0x0, 0x12, 0x00, 0x80, 0x0, 0x0, 0x0, 0x0,
        0x01, 0x0A,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
    };
    unsigned char *ptr = us->iobuf;
    unsigned long capacity;
    unsigned int lba;
    unsigned int pba;
    unsigned int page;
    unsigned short pages;
    struct sddr55_card_info *info;

    if (!us->extra) {
        us->extra = kzalloc(
            sizeof(struct sddr55_card_info), GFP_NOIO);
        if (!us->extra)
            return USB_STOR_TRANSPORT_ERROR;
        us->extra_destructor = sddr55_card_info_destructor;
    }

    info = (struct sddr55_card_info *)(us->extra);

    if (srb->cmnd[0] == REQUEST_SENSE) {
        US_DEBUGP("SDDR55: request sense %02x/%02x/%02x\n", info->sense_data[2], info->sense_data[12], info->sense_data[13]);

        memcpy (ptr, info->sense_data, sizeof info->sense_data);
        ptr[0] = 0x70;
        ptr[7] = 11;
        usb_stor_set_xfer_buf (ptr, sizeof info->sense_data, srb);
        memset (info->sense_data, 0, sizeof info->sense_data);

        return USB_STOR_TRANSPORT_GOOD;
    }

    memset (info->sense_data, 0, sizeof info->sense_data);

    /* Dummy up a response for INQUIRY since SDDR55 doesn't
       respond to INQUIRY commands */

    if (srb->cmnd[0] == INQUIRY) {
        memcpy(ptr, inquiry_response, 8);
        fill_inquiry_response(us, ptr, 36);
        return USB_STOR_TRANSPORT_GOOD;
    }

    /* only check card status if the map isn't allocated, ie no card seen yet
     * or if it's been over half a second since we last accessed it
     */
    if (info->lba_to_pba == NULL || time_after(jiffies, info->last_access + HZ/2)) {

        /* check to see if a card is fitted */
        result = sddr55_status (us);
        if (result) {
            result = sddr55_status (us);
            if (!result) {
            set_sense_info (6, 0x28, 0);    /* new media, set unit attention, not ready to ready */
            }
            return USB_STOR_TRANSPORT_FAILED;
        }
    }

    /* if we detected a problem with the map when writing,
       don't allow any more access */
    if (info->fatal_error) {

        set_sense_info (3, 0x31, 0);
        return USB_STOR_TRANSPORT_FAILED;
    }

    if (srb->cmnd[0] == READ_CAPACITY) {

        capacity = sddr55_get_capacity(us);

        if (!capacity) {
            set_sense_info (3, 0x30, 0); /* incompatible medium */
            return USB_STOR_TRANSPORT_FAILED;
        }

        info->capacity = capacity;

        /* figure out the maximum logical block number, allowing for
         * the fact that only 250 out of every 256 are used */
        info->max_log_blks = ((info->capacity >> (info->pageshift + info->blockshift)) / 256) * 250;

        /* Last page in the card, adjust as we only use 250 out of
         * every 256 pages */
        capacity = (capacity / 256) * 250;

        capacity /= PAGESIZE;
        capacity--;

        ((__be32 *) ptr)[0] = cpu_to_be32(capacity);
        ((__be32 *) ptr)[1] = cpu_to_be32(PAGESIZE);
        usb_stor_set_xfer_buf(ptr, 8, srb);

        sddr55_read_map(us);

        return USB_STOR_TRANSPORT_GOOD;
    }

    if (srb->cmnd[0] == MODE_SENSE_10) {

        memcpy(ptr, mode_page_01, sizeof mode_page_01);
        ptr[3] = (info->read_only || info->force_read_only) ? 0x80 : 0;
        usb_stor_set_xfer_buf(ptr, sizeof(mode_page_01), srb);

        if ( (srb->cmnd[2] & 0x3F) == 0x01 ) {
            US_DEBUGP(
              "SDDR55: Dummy up request for mode page 1\n");
            return USB_STOR_TRANSPORT_GOOD;

        } else if ( (srb->cmnd[2] & 0x3F) == 0x3F ) {
            US_DEBUGP(
              "SDDR55: Dummy up request for all mode pages\n");
            return USB_STOR_TRANSPORT_GOOD;
        }

        set_sense_info (5, 0x24, 0);    /* invalid field in command */
        return USB_STOR_TRANSPORT_FAILED;
    }

    if (srb->cmnd[0] == ALLOW_MEDIUM_REMOVAL) {

        US_DEBUGP(
          "SDDR55: %s medium removal. Not that I can do"
          " anything about it...\n",
          (srb->cmnd[4]&0x03) ? "Prevent" : "Allow");

        return USB_STOR_TRANSPORT_GOOD;

    }

    if (srb->cmnd[0] == READ_10 || srb->cmnd[0] == WRITE_10) {

        page = short_pack(srb->cmnd[3], srb->cmnd[2]);
        page <<= 16;
        page |= short_pack(srb->cmnd[5], srb->cmnd[4]);
        pages = short_pack(srb->cmnd[8], srb->cmnd[7]);

        page <<= info->smallpageshift;

        // convert page to block and page-within-block

        lba = page >> info->blockshift;
        page = page & info->blockmask;

        // locate physical block corresponding to logical block

        if (lba >= info->max_log_blks) {

            US_DEBUGP("Error: Requested LBA %04X exceeds maximum "
              "block %04X\n", lba, info->max_log_blks-1);

            set_sense_info (5, 0x24, 0);    /* invalid field in command */

            return USB_STOR_TRANSPORT_FAILED;
        }

        pba = info->lba_to_pba[lba];

        if (srb->cmnd[0] == WRITE_10) {
            US_DEBUGP("WRITE_10: write block %04X (LBA %04X) page %01X"
                " pages %d\n",
                pba, lba, page, pages);

            return sddr55_write_data(us, lba, page, pages);
        } else {
            US_DEBUGP("READ_10: read block %04X (LBA %04X) page %01X"
                " pages %d\n",
                pba, lba, page, pages);

            return sddr55_read_data(us, lba, page, pages);
        }
    }


    if (srb->cmnd[0] == TEST_UNIT_READY) {
        return USB_STOR_TRANSPORT_GOOD;
    }

    if (srb->cmnd[0] == START_STOP) {
        return USB_STOR_TRANSPORT_GOOD;
    }

    set_sense_info (5, 0x20, 0);    /* illegal command */

    return USB_STOR_TRANSPORT_FAILED; // FIXME: sense buffer?
}


static int sddr55_probe(struct usb_interface *intf,
             const struct usb_device_id *id)
{
    struct us_data *us;
    int result;

    result = usb_stor_probe1(&us, intf, id,
            (id - sddr55_usb_ids) + sddr55_unusual_dev_list);
    if (result)
        return result;

    us->transport_name = "SDDR55";
    us->transport = sddr55_transport;
    us->transport_reset = sddr55_reset;
    us->max_lun = 0;

    result = usb_stor_probe2(us);
    return result;
}

static struct usb_driver sddr55_driver = {
    .name =     "ums-sddr55",
    .probe =    sddr55_probe,
    .disconnect =   usb_stor_disconnect,
    .suspend =  usb_stor_suspend,
    .resume =   usb_stor_resume,
    .reset_resume = usb_stor_reset_resume,
    .pre_reset =    usb_stor_pre_reset,
    .post_reset =   usb_stor_post_reset,
    .id_table = sddr55_usb_ids,
    .soft_unbind =  1,
    .no_dynamic_id = 1,
};

module_usb_driver(sddr55_driver);