// SPDX-License-Identifier: GPL-2.0+
/*
 * Driver for SanDisk SDDR-55 SmartMedia reader
 *
 * SDDR55 driver v0.1:
 *
 * First release
 *
 * Current development and maintenance by:
 *   (c) 2002 Simon Munton
 */

#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"
#include "scsiglue.h"

#define DRV_NAME "ums-sddr55"

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);

        usb_stor_dbg(us, "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;

                usb_stor_dbg(us, "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);

                        usb_stor_dbg(us, "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);

                usb_stor_dbg(us, "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;

                        usb_stor_dbg(us, "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 */
                                usb_stor_dbg(us, "Couldn't find unallocated block\n");

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

                        usb_stor_dbg(us, "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) {
                        usb_stor_dbg(us, "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) {
                        usb_stor_dbg(us, "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) {
                        usb_stor_dbg(us, "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;
                }

                usb_stor_dbg(us, "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);

        usb_stor_dbg(us, "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;

        usb_stor_dbg(us, "Reading capacity...\n");

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

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

        if (result != USB_STOR_XFER_GOOD)
                return 0;

        usb_stor_dbg(us, "Device ID = %02X\n", deviceID);
        usb_stor_dbg(us, "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;
                /* fall through */
        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_array(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_array(numblocks, sizeof(int), GFP_NOIO);
        info->pba_to_lba = kmalloc_array(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))
                        usb_stor_dbg(us, "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) {
                usb_stor_dbg(us, "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 ) {
                        usb_stor_dbg(us, "Dummy up request for mode page 1\n");
                        return USB_STOR_TRANSPORT_GOOD;

                } else if ( (srb->cmnd[2] & 0x3F) == 0x3F ) {
                        usb_stor_dbg(us, "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) {

                usb_stor_dbg(us, "%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) {

                        usb_stor_dbg(us, "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) {
                        usb_stor_dbg(us, "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 {
                        usb_stor_dbg(us, "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 struct scsi_host_template sddr55_host_template;

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,
                        &sddr55_host_template);
        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 =         DRV_NAME,
        .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_stor_driver(sddr55_driver, sddr55_host_template, DRV_NAME);