[PATCH] USB: more device IDs for Option card driver

[linux-2.6] / drivers / usb / storage / sddr09.c

/* Driver for SanDisk SDDR-09 SmartMedia reader
 *
 * $Id: sddr09.c,v 1.24 2002/04/22 03:39:43 mdharm Exp $
 *   (c) 2000, 2001 Robert Baruch (autophile@starband.net)
 *   (c) 2002 Andries Brouwer (aeb@cwi.nl)
 * Developed with the assistance of:
 *   (c) 2002 Alan Stern <stern@rowland.org>
 *
 * The SanDisk SDDR-09 SmartMedia reader uses the Shuttle EUSB-01 chip.
 * This chip is a programmable USB controller. In the SDDR-09, it has
 * been programmed to obey a certain limited set of SCSI commands.
 * This driver translates the "real" SCSI commands to the SDDR-09 SCSI
 * commands.
 *
 * 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.
 */

/*
 * Known vendor commands: 12 bytes, first byte is opcode
 *
 * E7: read scatter gather
 * E8: read
 * E9: write
 * EA: erase
 * EB: reset
 * EC: read status
 * ED: read ID
 * EE: write CIS (?)
 * EF: compute checksum (?)
 */

#include <linux/sched.h>
#include <linux/errno.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 "sddr09.h"


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

/* #define US_DEBUGP printk */

/*
 * First some stuff that does not belong here:
 * data on SmartMedia and other cards, completely
 * unrelated to this driver.
 * Similar stuff occurs in <linux/mtd/nand_ids.h>.
 */

struct nand_flash_dev {
        int model_id;
        int chipshift;          /* 1<<cs bytes total capacity */
        char pageshift;         /* 1<<ps bytes in a page */
        char blockshift;        /* 1<<bs pages in an erase block */
        char zoneshift;         /* 1<<zs blocks in a zone */
                                /* # of logical blocks is 125/128 of this */
        char pageadrlen;        /* length of an address in bytes - 1 */
};

/*
 * NAND Flash Manufacturer ID Codes
 */
#define NAND_MFR_AMD            0x01
#define NAND_MFR_NATSEMI        0x8f
#define NAND_MFR_TOSHIBA        0x98
#define NAND_MFR_SAMSUNG        0xec

static inline char *nand_flash_manufacturer(int manuf_id) {
        switch(manuf_id) {
        case NAND_MFR_AMD:
                return "AMD";
        case NAND_MFR_NATSEMI:
                return "NATSEMI";
        case NAND_MFR_TOSHIBA:
                return "Toshiba";
        case NAND_MFR_SAMSUNG:
                return "Samsung";
        default:
                return "unknown";
        }
}

/*
 * It looks like it is unnecessary to attach manufacturer to the
 * remaining data: SSFDC prescribes manufacturer-independent id codes.
 *
 * 256 MB NAND flash has a 5-byte ID with 2nd byte 0xaa, 0xba, 0xca or 0xda.
 */

static struct nand_flash_dev nand_flash_ids[] = {
        /* NAND flash */
        { 0x6e, 20, 8, 4, 8, 2},        /* 1 MB */
        { 0xe8, 20, 8, 4, 8, 2},        /* 1 MB */
        { 0xec, 20, 8, 4, 8, 2},        /* 1 MB */
        { 0x64, 21, 8, 4, 9, 2},        /* 2 MB */
        { 0xea, 21, 8, 4, 9, 2},        /* 2 MB */
        { 0x6b, 22, 9, 4, 9, 2},        /* 4 MB */
        { 0xe3, 22, 9, 4, 9, 2},        /* 4 MB */
        { 0xe5, 22, 9, 4, 9, 2},        /* 4 MB */
        { 0xe6, 23, 9, 4, 10, 2},       /* 8 MB */
        { 0x73, 24, 9, 5, 10, 2},       /* 16 MB */
        { 0x75, 25, 9, 5, 10, 2},       /* 32 MB */
        { 0x76, 26, 9, 5, 10, 3},       /* 64 MB */
        { 0x79, 27, 9, 5, 10, 3},       /* 128 MB */

        /* MASK ROM */
        { 0x5d, 21, 9, 4, 8, 2},        /* 2 MB */
        { 0xd5, 22, 9, 4, 9, 2},        /* 4 MB */
        { 0xd6, 23, 9, 4, 10, 2},       /* 8 MB */
        { 0x57, 24, 9, 4, 11, 2},       /* 16 MB */
        { 0x58, 25, 9, 4, 12, 2},       /* 32 MB */
        { 0,}
};

#define SIZE(a) (sizeof(a)/sizeof((a)[0]))

static struct nand_flash_dev *
nand_find_id(unsigned char id) {
        int i;

        for (i = 0; i < SIZE(nand_flash_ids); i++)
                if (nand_flash_ids[i].model_id == id)
                        return &(nand_flash_ids[i]);
        return NULL;
}

/*
 * ECC computation.
 */
static unsigned char parity[256];
static unsigned char ecc2[256];

static void nand_init_ecc(void) {
        int i, j, a;

        parity[0] = 0;
        for (i = 1; i < 256; i++)
                parity[i] = (parity[i&(i-1)] ^ 1);

        for (i = 0; i < 256; i++) {
                a = 0;
                for (j = 0; j < 8; j++) {
                        if (i & (1<<j)) {
                                if ((j & 1) == 0)
                                        a ^= 0x04;
                                if ((j & 2) == 0)
                                        a ^= 0x10;
                                if ((j & 4) == 0)
                                        a ^= 0x40;
                        }
                }
                ecc2[i] = ~(a ^ (a<<1) ^ (parity[i] ? 0xa8 : 0));
        }
}

/* compute 3-byte ecc on 256 bytes */
static void nand_compute_ecc(unsigned char *data, unsigned char *ecc) {
        int i, j, a;
        unsigned char par, bit, bits[8];

        par = 0;
        for (j = 0; j < 8; j++)
                bits[j] = 0;

        /* collect 16 checksum bits */
        for (i = 0; i < 256; i++) {
                par ^= data[i];
                bit = parity[data[i]];
                for (j = 0; j < 8; j++)
                        if ((i & (1<<j)) == 0)
                                bits[j] ^= bit;
        }

        /* put 4+4+4 = 12 bits in the ecc */
        a = (bits[3] << 6) + (bits[2] << 4) + (bits[1] << 2) + bits[0];
        ecc[0] = ~(a ^ (a<<1) ^ (parity[par] ? 0xaa : 0));

        a = (bits[7] << 6) + (bits[6] << 4) + (bits[5] << 2) + bits[4];
        ecc[1] = ~(a ^ (a<<1) ^ (parity[par] ? 0xaa : 0));

        ecc[2] = ecc2[par];
}

static int nand_compare_ecc(unsigned char *data, unsigned char *ecc) {
        return (data[0] == ecc[0] && data[1] == ecc[1] && data[2] == ecc[2]);
}

static void nand_store_ecc(unsigned char *data, unsigned char *ecc) {
        memcpy(data, ecc, 3);
}

/*
 * The actual driver starts here.
 */

/*
 * On my 16MB card, control blocks have size 64 (16 real control bytes,
 * and 48 junk bytes). In reality of course the card uses 16 control bytes,
 * so the reader makes up the remaining 48. Don't know whether these numbers
 * depend on the card. For now a constant.
 */
#define CONTROL_SHIFT 6

/*
 * On my Combo CF/SM reader, the SM reader has LUN 1.
 * (and things fail with LUN 0).
 * It seems LUN is irrelevant for others.
 */
#define LUN     1
#define LUNBITS (LUN << 5)

/*
 * LBA and PBA are unsigned ints. Special values.
 */
#define UNDEF    0xffffffff
#define SPARE    0xfffffffe
#define UNUSABLE 0xfffffffd

static int erase_bad_lba_entries = 0;

/* send vendor interface command (0x41) */
/* called for requests 0, 1, 8 */
static int
sddr09_send_command(struct us_data *us,
                    unsigned char request,
                    unsigned char direction,
                    unsigned char *xfer_data,
                    unsigned int xfer_len) {
        unsigned int pipe;
        unsigned char requesttype = (0x41 | direction);
        int rc;

        // Get the receive or send control pipe number

        if (direction == USB_DIR_IN)
                pipe = us->recv_ctrl_pipe;
        else
                pipe = us->send_ctrl_pipe;

        rc = usb_stor_ctrl_transfer(us, pipe, request, requesttype,
                                   0, 0, xfer_data, xfer_len);
        return (rc == USB_STOR_XFER_GOOD ? USB_STOR_TRANSPORT_GOOD :
                        USB_STOR_TRANSPORT_ERROR);
}

static int
sddr09_send_scsi_command(struct us_data *us,
                         unsigned char *command,
                         unsigned int command_len) {
        return sddr09_send_command(us, 0, USB_DIR_OUT, command, command_len);
}

#if 0
/*
 * Test Unit Ready Command: 12 bytes.
 * byte 0: opcode: 00
 */
static int
sddr09_test_unit_ready(struct us_data *us) {
        unsigned char *command = us->iobuf;
        int result;

        memset(command, 0, 6);
        command[1] = LUNBITS;

        result = sddr09_send_scsi_command(us, command, 6);

        US_DEBUGP("sddr09_test_unit_ready returns %d\n", result);

        return result;
}
#endif

/*
 * Request Sense Command: 12 bytes.
 * byte 0: opcode: 03
 * byte 4: data length
 */
static int
sddr09_request_sense(struct us_data *us, unsigned char *sensebuf, int buflen) {
        unsigned char *command = us->iobuf;
        int result;

        memset(command, 0, 12);
        command[0] = 0x03;
        command[1] = LUNBITS;
        command[4] = buflen;

        result = sddr09_send_scsi_command(us, command, 12);
        if (result != USB_STOR_TRANSPORT_GOOD) {
                US_DEBUGP("request sense failed\n");
                return result;
        }

        result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
                        sensebuf, buflen, NULL);
        if (result != USB_STOR_XFER_GOOD) {
                US_DEBUGP("request sense bulk in failed\n");
                return USB_STOR_TRANSPORT_ERROR;
        } else {
                US_DEBUGP("request sense worked\n");
                return USB_STOR_TRANSPORT_GOOD;
        }
}

/*
 * Read Command: 12 bytes.
 * byte 0: opcode: E8
 * byte 1: last two bits: 00: read data, 01: read blockwise control,
 *                      10: read both, 11: read pagewise control.
 *       It turns out we need values 20, 21, 22, 23 here (LUN 1).
 * bytes 2-5: address (interpretation depends on byte 1, see below)
 * bytes 10-11: count (idem)
 *
 * A page has 512 data bytes and 64 control bytes (16 control and 48 junk).
 * A read data command gets data in 512-byte pages.
 * A read control command gets control in 64-byte chunks.
 * A read both command gets data+control in 576-byte chunks.
 *
 * Blocks are groups of 32 pages, and read blockwise control jumps to the
 * next block, while read pagewise control jumps to the next page after
 * reading a group of 64 control bytes.
 * [Here 512 = 1<<pageshift, 32 = 1<<blockshift, 64 is constant?]
 *
 * (1 MB and 2 MB cards are a bit different, but I have only a 16 MB card.)
 */

static int
sddr09_readX(struct us_data *us, int x, unsigned long fromaddress,
             int nr_of_pages, int bulklen, unsigned char *buf,
             int use_sg) {

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

        command[0] = 0xE8;
        command[1] = LUNBITS | x;
        command[2] = MSB_of(fromaddress>>16);
        command[3] = LSB_of(fromaddress>>16); 
        command[4] = MSB_of(fromaddress & 0xFFFF);
        command[5] = LSB_of(fromaddress & 0xFFFF); 
        command[6] = 0;
        command[7] = 0;
        command[8] = 0;
        command[9] = 0;
        command[10] = MSB_of(nr_of_pages);
        command[11] = LSB_of(nr_of_pages);

        result = sddr09_send_scsi_command(us, command, 12);

        if (result != USB_STOR_TRANSPORT_GOOD) {
                US_DEBUGP("Result for send_control in sddr09_read2%d %d\n",
                          x, result);
                return result;
        }

        result = usb_stor_bulk_transfer_sg(us, us->recv_bulk_pipe,
                                       buf, bulklen, use_sg, NULL);

        if (result != USB_STOR_XFER_GOOD) {
                US_DEBUGP("Result for bulk_transfer in sddr09_read2%d %d\n",
                          x, result);
                return USB_STOR_TRANSPORT_ERROR;
        }
        return USB_STOR_TRANSPORT_GOOD;
}

/*
 * Read Data
 *
 * fromaddress counts data shorts:
 * increasing it by 256 shifts the bytestream by 512 bytes;
 * the last 8 bits are ignored.
 *
 * nr_of_pages counts pages of size (1 << pageshift).
 */
static int
sddr09_read20(struct us_data *us, unsigned long fromaddress,
              int nr_of_pages, int pageshift, unsigned char *buf, int use_sg) {
        int bulklen = nr_of_pages << pageshift;

        /* The last 8 bits of fromaddress are ignored. */
        return sddr09_readX(us, 0, fromaddress, nr_of_pages, bulklen,
                            buf, use_sg);
}

/*
 * Read Blockwise Control
 *
 * fromaddress gives the starting position (as in read data;
 * the last 8 bits are ignored); increasing it by 32*256 shifts
 * the output stream by 64 bytes.
 *
 * count counts control groups of size (1 << controlshift).
 * For me, controlshift = 6. Is this constant?
 *
 * After getting one control group, jump to the next block
 * (fromaddress += 8192).
 */
static int
sddr09_read21(struct us_data *us, unsigned long fromaddress,
              int count, int controlshift, unsigned char *buf, int use_sg) {

        int bulklen = (count << controlshift);
        return sddr09_readX(us, 1, fromaddress, count, bulklen,
                            buf, use_sg);
}

/*
 * Read both Data and Control
 *
 * fromaddress counts data shorts, ignoring control:
 * increasing it by 256 shifts the bytestream by 576 = 512+64 bytes;
 * the last 8 bits are ignored.
 *
 * nr_of_pages counts pages of size (1 << pageshift) + (1 << controlshift).
 */
static int
sddr09_read22(struct us_data *us, unsigned long fromaddress,
              int nr_of_pages, int pageshift, unsigned char *buf, int use_sg) {

        int bulklen = (nr_of_pages << pageshift) + (nr_of_pages << CONTROL_SHIFT);
        US_DEBUGP("sddr09_read22: reading %d pages, %d bytes\n",
                  nr_of_pages, bulklen);
        return sddr09_readX(us, 2, fromaddress, nr_of_pages, bulklen,
                            buf, use_sg);
}

#if 0
/*
 * Read Pagewise Control
 *
 * fromaddress gives the starting position (as in read data;
 * the last 8 bits are ignored); increasing it by 256 shifts
 * the output stream by 64 bytes.
 *
 * count counts control groups of size (1 << controlshift).
 * For me, controlshift = 6. Is this constant?
 *
 * After getting one control group, jump to the next page
 * (fromaddress += 256).
 */
static int
sddr09_read23(struct us_data *us, unsigned long fromaddress,
              int count, int controlshift, unsigned char *buf, int use_sg) {

        int bulklen = (count << controlshift);
        return sddr09_readX(us, 3, fromaddress, count, bulklen,
                            buf, use_sg);
}
#endif

/*
 * Erase Command: 12 bytes.
 * byte 0: opcode: EA
 * bytes 6-9: erase address (big-endian, counting shorts, sector aligned).
 * 
 * Always precisely one block is erased; bytes 2-5 and 10-11 are ignored.
 * The byte address being erased is 2*Eaddress.
 * The CIS cannot be erased.
 */
static int
sddr09_erase(struct us_data *us, unsigned long Eaddress) {
        unsigned char *command = us->iobuf;
        int result;

        US_DEBUGP("sddr09_erase: erase address %lu\n", Eaddress);

        memset(command, 0, 12);
        command[0] = 0xEA;
        command[1] = LUNBITS;
        command[6] = MSB_of(Eaddress>>16);
        command[7] = LSB_of(Eaddress>>16);
        command[8] = MSB_of(Eaddress & 0xFFFF);
        command[9] = LSB_of(Eaddress & 0xFFFF);

        result = sddr09_send_scsi_command(us, command, 12);

        if (result != USB_STOR_TRANSPORT_GOOD)
                US_DEBUGP("Result for send_control in sddr09_erase %d\n",
                          result);

        return result;
}

/*
 * Write CIS Command: 12 bytes.
 * byte 0: opcode: EE
 * bytes 2-5: write address in shorts
 * bytes 10-11: sector count
 *
 * This writes at the indicated address. Don't know how it differs
 * from E9. Maybe it does not erase? However, it will also write to
 * the CIS.
 *
 * When two such commands on the same page follow each other directly,
 * the second one is not done.
 */

/*
 * Write Command: 12 bytes.
 * byte 0: opcode: E9
 * bytes 2-5: write address (big-endian, counting shorts, sector aligned).
 * bytes 6-9: erase address (big-endian, counting shorts, sector aligned).
 * bytes 10-11: sector count (big-endian, in 512-byte sectors).
 *
 * If write address equals erase address, the erase is done first,
 * otherwise the write is done first. When erase address equals zero
 * no erase is done?
 */
static int
sddr09_writeX(struct us_data *us,
              unsigned long Waddress, unsigned long Eaddress,
              int nr_of_pages, int bulklen, unsigned char *buf, int use_sg) {

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

        command[0] = 0xE9;
        command[1] = LUNBITS;

        command[2] = MSB_of(Waddress>>16);
        command[3] = LSB_of(Waddress>>16);
        command[4] = MSB_of(Waddress & 0xFFFF);
        command[5] = LSB_of(Waddress & 0xFFFF);

        command[6] = MSB_of(Eaddress>>16);
        command[7] = LSB_of(Eaddress>>16);
        command[8] = MSB_of(Eaddress & 0xFFFF);
        command[9] = LSB_of(Eaddress & 0xFFFF);

        command[10] = MSB_of(nr_of_pages);
        command[11] = LSB_of(nr_of_pages);

        result = sddr09_send_scsi_command(us, command, 12);

        if (result != USB_STOR_TRANSPORT_GOOD) {
                US_DEBUGP("Result for send_control in sddr09_writeX %d\n",
                          result);
                return result;
        }

        result = usb_stor_bulk_transfer_sg(us, us->send_bulk_pipe,
                                       buf, bulklen, use_sg, NULL);

        if (result != USB_STOR_XFER_GOOD) {
                US_DEBUGP("Result for bulk_transfer in sddr09_writeX %d\n",
                          result);
                return USB_STOR_TRANSPORT_ERROR;
        }
        return USB_STOR_TRANSPORT_GOOD;
}

/* erase address, write same address */
static int
sddr09_write_inplace(struct us_data *us, unsigned long address,
                     int nr_of_pages, int pageshift, unsigned char *buf,
                     int use_sg) {
        int bulklen = (nr_of_pages << pageshift) + (nr_of_pages << CONTROL_SHIFT);
        return sddr09_writeX(us, address, address, nr_of_pages, bulklen,
                             buf, use_sg);
}

#if 0
/*
 * Read Scatter Gather Command: 3+4n bytes.
 * byte 0: opcode E7
 * byte 2: n
 * bytes 4i-1,4i,4i+1: page address
 * byte 4i+2: page count
 * (i=1..n)
 *
 * This reads several pages from the card to a single memory buffer.
 * The last two bits of byte 1 have the same meaning as for E8.
 */
static int
sddr09_read_sg_test_only(struct us_data *us) {
        unsigned char *command = us->iobuf;
        int result, bulklen, nsg, ct;
        unsigned char *buf;
        unsigned long address;

        nsg = bulklen = 0;
        command[0] = 0xE7;
        command[1] = LUNBITS;
        command[2] = 0;
        address = 040000; ct = 1;
        nsg++;
        bulklen += (ct << 9);
        command[4*nsg+2] = ct;
        command[4*nsg+1] = ((address >> 9) & 0xFF);
        command[4*nsg+0] = ((address >> 17) & 0xFF);
        command[4*nsg-1] = ((address >> 25) & 0xFF);

        address = 0340000; ct = 1;
        nsg++;
        bulklen += (ct << 9);
        command[4*nsg+2] = ct;
        command[4*nsg+1] = ((address >> 9) & 0xFF);
        command[4*nsg+0] = ((address >> 17) & 0xFF);
        command[4*nsg-1] = ((address >> 25) & 0xFF);

        address = 01000000; ct = 2;
        nsg++;
        bulklen += (ct << 9);
        command[4*nsg+2] = ct;
        command[4*nsg+1] = ((address >> 9) & 0xFF);
        command[4*nsg+0] = ((address >> 17) & 0xFF);
        command[4*nsg-1] = ((address >> 25) & 0xFF);

        command[2] = nsg;

        result = sddr09_send_scsi_command(us, command, 4*nsg+3);

        if (result != USB_STOR_TRANSPORT_GOOD) {
                US_DEBUGP("Result for send_control in sddr09_read_sg %d\n",
                          result);
                return result;
        }

        buf = (unsigned char *) kmalloc(bulklen, GFP_NOIO);
        if (!buf)
                return USB_STOR_TRANSPORT_ERROR;

        result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
                                       buf, bulklen, NULL);
        kfree(buf);
        if (result != USB_STOR_XFER_GOOD) {
                US_DEBUGP("Result for bulk_transfer in sddr09_read_sg %d\n",
                          result);
                return USB_STOR_TRANSPORT_ERROR;
        }

        return USB_STOR_TRANSPORT_GOOD;
}
#endif

/*
 * Read Status Command: 12 bytes.
 * byte 0: opcode: EC
 *
 * Returns 64 bytes, all zero except for the first.
 * bit 0: 1: Error
 * bit 5: 1: Suspended
 * bit 6: 1: Ready
 * bit 7: 1: Not write-protected
 */

static int
sddr09_read_status(struct us_data *us, unsigned char *status) {

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

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

        memset(command, 0, 12);
        command[0] = 0xEC;
        command[1] = LUNBITS;

        result = sddr09_send_scsi_command(us, command, 12);
        if (result != USB_STOR_TRANSPORT_GOOD)
                return result;

        result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
                                       data, 64, NULL);
        *status = data[0];
        return (result == USB_STOR_XFER_GOOD ?
                        USB_STOR_TRANSPORT_GOOD : USB_STOR_TRANSPORT_ERROR);
}

static int
sddr09_read_data(struct us_data *us,
                 unsigned long address,
                 unsigned int sectors) {

        struct sddr09_card_info *info = (struct sddr09_card_info *) us->extra;
        unsigned char *buffer;
        unsigned int lba, maxlba, pba;
        unsigned int page, pages;
        unsigned int len, index, offset;
        int result;

        // 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(sectors, (unsigned int) info->blocksize) * info->pagesize;
        buffer = kmalloc(len, GFP_NOIO);
        if (buffer == NULL) {
                printk("sddr09_read_data: Out of memory\n");
                return USB_STOR_TRANSPORT_ERROR;
        }

        // Figure out the initial LBA and page
        lba = address >> info->blockshift;
        page = (address & info->blockmask);
        maxlba = info->capacity >> (info->pageshift + info->blockshift);

        // This could be made much more efficient by checking for
        // contiguous LBA's. Another exercise left to the student.

        result = USB_STOR_TRANSPORT_GOOD;
        index = offset = 0;

        while (sectors > 0) {

                /* Find number of pages we can read in this block */
                pages = min(sectors, info->blocksize - page);
                len = pages << info->pageshift;

                /* Not overflowing capacity? */
                if (lba >= maxlba) {
                        US_DEBUGP("Error: Requested lba %u exceeds "
                                  "maximum %u\n", lba, maxlba);
                        result = USB_STOR_TRANSPORT_ERROR;
                        break;
                }

                /* Find where this lba lives on disk */
                pba = info->lba_to_pba[lba];

                if (pba == UNDEF) {     /* this lba was never written */

                        US_DEBUGP("Read %d zero pages (LBA %d) page %d\n",
                                  pages, lba, page);

                        /* This is not really an error. It just means
                           that the block has never been written.
                           Instead of returning USB_STOR_TRANSPORT_ERROR
                           it is better to return all zero data. */

                        memset(buffer, 0, len);

                } else {
                        US_DEBUGP("Read %d pages, from PBA %d"
                                  " (LBA %d) page %d\n",
                                  pages, pba, lba, page);

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

                        result = sddr09_read20(us, address>>1,
                                        pages, info->pageshift, buffer, 0);
                        if (result != USB_STOR_TRANSPORT_GOOD)
                                break;
                }

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

                page = 0;
                lba++;
                sectors -= pages;
        }

        kfree(buffer);
        return result;
}

static unsigned int
sddr09_find_unused_pba(struct sddr09_card_info *info, unsigned int lba) {
        static unsigned int lastpba = 1;
        int zonestart, end, i;

        zonestart = (lba/1000) << 10;
        end = info->capacity >> (info->blockshift + info->pageshift);
        end -= zonestart;
        if (end > 1024)
                end = 1024;

        for (i = lastpba+1; i < end; i++) {
                if (info->pba_to_lba[zonestart+i] == UNDEF) {
                        lastpba = i;
                        return zonestart+i;
                }
        }
        for (i = 0; i <= lastpba; i++) {
                if (info->pba_to_lba[zonestart+i] == UNDEF) {
                        lastpba = i;
                        return zonestart+i;
                }
        }
        return 0;
}

static int
sddr09_write_lba(struct us_data *us, unsigned int lba,
                 unsigned int page, unsigned int pages,
                 unsigned char *ptr, unsigned char *blockbuffer) {

        struct sddr09_card_info *info = (struct sddr09_card_info *) us->extra;
        unsigned long address;
        unsigned int pba, lbap;
        unsigned int pagelen;
        unsigned char *bptr, *cptr, *xptr;
        unsigned char ecc[3];
        int i, result, isnew;

        lbap = ((lba % 1000) << 1) | 0x1000;
        if (parity[MSB_of(lbap) ^ LSB_of(lbap)])
                lbap ^= 1;
        pba = info->lba_to_pba[lba];
        isnew = 0;

        if (pba == UNDEF) {
                pba = sddr09_find_unused_pba(info, lba);
                if (!pba) {
                        printk("sddr09_write_lba: Out of unused blocks\n");
                        return USB_STOR_TRANSPORT_ERROR;
                }
                info->pba_to_lba[pba] = lba;
                info->lba_to_pba[lba] = pba;
                isnew = 1;
        }

        if (pba == 1) {
                /* Maybe it is impossible to write to PBA 1.
                   Fake success, but don't do anything. */
                printk("sddr09: avoid writing to pba 1\n");
                return USB_STOR_TRANSPORT_GOOD;
        }

        pagelen = (1 << info->pageshift) + (1 << CONTROL_SHIFT);

        /* read old contents */
        address = (pba << (info->pageshift + info->blockshift));
        result = sddr09_read22(us, address>>1, info->blocksize,
                               info->pageshift, blockbuffer, 0);
        if (result != USB_STOR_TRANSPORT_GOOD)
                return result;

        /* check old contents and fill lba */
        for (i = 0; i < info->blocksize; i++) {
                bptr = blockbuffer + i*pagelen;
                cptr = bptr + info->pagesize;
                nand_compute_ecc(bptr, ecc);
                if (!nand_compare_ecc(cptr+13, ecc)) {
                        US_DEBUGP("Warning: bad ecc in page %d- of pba %d\n",
                                  i, pba);
                        nand_store_ecc(cptr+13, ecc);
                }
                nand_compute_ecc(bptr+(info->pagesize / 2), ecc);
                if (!nand_compare_ecc(cptr+8, ecc)) {
                        US_DEBUGP("Warning: bad ecc in page %d+ of pba %d\n",
                                  i, pba);
                        nand_store_ecc(cptr+8, ecc);
                }
                cptr[6] = cptr[11] = MSB_of(lbap);
                cptr[7] = cptr[12] = LSB_of(lbap);
        }

        /* copy in new stuff and compute ECC */
        xptr = ptr;
        for (i = page; i < page+pages; i++) {
                bptr = blockbuffer + i*pagelen;
                cptr = bptr + info->pagesize;
                memcpy(bptr, xptr, info->pagesize);
                xptr += info->pagesize;
                nand_compute_ecc(bptr, ecc);
                nand_store_ecc(cptr+13, ecc);
                nand_compute_ecc(bptr+(info->pagesize / 2), ecc);
                nand_store_ecc(cptr+8, ecc);
        }

        US_DEBUGP("Rewrite PBA %d (LBA %d)\n", pba, lba);

        result = sddr09_write_inplace(us, address>>1, info->blocksize,
                                      info->pageshift, blockbuffer, 0);

        US_DEBUGP("sddr09_write_inplace returns %d\n", result);

#if 0
        {
                unsigned char status = 0;
                int result2 = sddr09_read_status(us, &status);
                if (result2 != USB_STOR_TRANSPORT_GOOD)
                        US_DEBUGP("sddr09_write_inplace: cannot read status\n");
                else if (status != 0xc0)
                        US_DEBUGP("sddr09_write_inplace: status after write: 0x%x\n",
                                  status);
        }
#endif

#if 0
        {
                int result2 = sddr09_test_unit_ready(us);
        }
#endif

        return result;
}

static int
sddr09_write_data(struct us_data *us,
                  unsigned long address,
                  unsigned int sectors) {

        struct sddr09_card_info *info = (struct sddr09_card_info *) us->extra;
        unsigned int lba, page, pages;
        unsigned int pagelen, blocklen;
        unsigned char *blockbuffer;
        unsigned char *buffer;
        unsigned int len, index, offset;
        int result;

        // blockbuffer is used for reading in the old data, overwriting
        // with the new data, and performing ECC calculations

        /* TODO: instead of doing kmalloc/kfree for each write,
           add a bufferpointer to the info structure */

        pagelen = (1 << info->pageshift) + (1 << CONTROL_SHIFT);
        blocklen = (pagelen << info->blockshift);
        blockbuffer = kmalloc(blocklen, GFP_NOIO);
        if (!blockbuffer) {
                printk("sddr09_write_data: Out of memory\n");
                return USB_STOR_TRANSPORT_ERROR;
        }

        // Since we don't write the user data directly to the device,
        // 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(sectors, (unsigned int) info->blocksize) * info->pagesize;
        buffer = kmalloc(len, GFP_NOIO);
        if (buffer == NULL) {
                printk("sddr09_write_data: Out of memory\n");
                kfree(blockbuffer);
                return USB_STOR_TRANSPORT_ERROR;
        }

        // Figure out the initial LBA and page
        lba = address >> info->blockshift;
        page = (address & info->blockmask);

        result = USB_STOR_TRANSPORT_GOOD;
        index = offset = 0;

        while (sectors > 0) {

                // Write as many sectors as possible in this block

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

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

                result = sddr09_write_lba(us, lba, page, pages,
                                buffer, blockbuffer);
                if (result != USB_STOR_TRANSPORT_GOOD)
                        break;

                page = 0;
                lba++;
                sectors -= pages;
        }

        kfree(buffer);
        kfree(blockbuffer);

        return result;
}

static int
sddr09_read_control(struct us_data *us,
                unsigned long address,
                unsigned int blocks,
                unsigned char *content,
                int use_sg) {

        US_DEBUGP("Read control address %lu, blocks %d\n",
                address, blocks);

        return sddr09_read21(us, address, blocks,
                             CONTROL_SHIFT, content, use_sg);
}

/*
 * Read Device ID Command: 12 bytes.
 * byte 0: opcode: ED
 *
 * Returns 2 bytes: Manufacturer ID and Device ID.
 * On more recent cards 3 bytes: the third byte is an option code A5
 * signifying that the secret command to read an 128-bit ID is available.
 * On still more recent cards 4 bytes: the fourth byte C0 means that
 * a second read ID cmd is available.
 */
static int
sddr09_read_deviceID(struct us_data *us, unsigned char *deviceID) {
        unsigned char *command = us->iobuf;
        unsigned char *content = us->iobuf;
        int result, i;

        memset(command, 0, 12);
        command[0] = 0xED;
        command[1] = LUNBITS;

        result = sddr09_send_scsi_command(us, command, 12);
        if (result != USB_STOR_TRANSPORT_GOOD)
                return result;

        result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
                        content, 64, NULL);

        for (i = 0; i < 4; i++)
                deviceID[i] = content[i];

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

static int
sddr09_get_wp(struct us_data *us, struct sddr09_card_info *info) {
        int result;
        unsigned char status;

        result = sddr09_read_status(us, &status);
        if (result != USB_STOR_TRANSPORT_GOOD) {
                US_DEBUGP("sddr09_get_wp: read_status fails\n");
                return result;
        }
        US_DEBUGP("sddr09_get_wp: status 0x%02X", status);
        if ((status & 0x80) == 0) {
                info->flags |= SDDR09_WP;       /* write protected */
                US_DEBUGP(" WP");
        }
        if (status & 0x40)
                US_DEBUGP(" Ready");
        if (status & LUNBITS)
                US_DEBUGP(" Suspended");
        if (status & 0x1)
                US_DEBUGP(" Error");
        US_DEBUGP("\n");
        return USB_STOR_TRANSPORT_GOOD;
}

#if 0
/*
 * Reset Command: 12 bytes.
 * byte 0: opcode: EB
 */
static int
sddr09_reset(struct us_data *us) {

        unsigned char *command = us->iobuf;

        memset(command, 0, 12);
        command[0] = 0xEB;
        command[1] = LUNBITS;

        return sddr09_send_scsi_command(us, command, 12);
}
#endif

static struct nand_flash_dev *
sddr09_get_cardinfo(struct us_data *us, unsigned char flags) {
        struct nand_flash_dev *cardinfo;
        unsigned char deviceID[4];
        char blurbtxt[256];
        int result;

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

        result = sddr09_read_deviceID(us, deviceID);

        if (result != USB_STOR_TRANSPORT_GOOD) {
                US_DEBUGP("Result of read_deviceID is %d\n", result);
                printk("sddr09: could not read card info\n");
                return NULL;
        }

        sprintf(blurbtxt, "sddr09: Found Flash card, ID = %02X %02X %02X %02X",
                deviceID[0], deviceID[1], deviceID[2], deviceID[3]);

        /* Byte 0 is the manufacturer */
        sprintf(blurbtxt + strlen(blurbtxt),
                ": Manuf. %s",
                nand_flash_manufacturer(deviceID[0]));

        /* Byte 1 is the device type */
        cardinfo = nand_find_id(deviceID[1]);
        if (cardinfo) {
                /* MB or MiB? It is neither. A 16 MB card has
                   17301504 raw bytes, of which 16384000 are
                   usable for user data. */
                sprintf(blurbtxt + strlen(blurbtxt),
                        ", %d MB", 1<<(cardinfo->chipshift - 20));
        } else {
                sprintf(blurbtxt + strlen(blurbtxt),
                        ", type unrecognized");
        }

        /* Byte 2 is code to signal availability of 128-bit ID */
        if (deviceID[2] == 0xa5) {
                sprintf(blurbtxt + strlen(blurbtxt),
                        ", 128-bit ID");
        }

        /* Byte 3 announces the availability of another read ID command */
        if (deviceID[3] == 0xc0) {
                sprintf(blurbtxt + strlen(blurbtxt),
                        ", extra cmd");
        }

        if (flags & SDDR09_WP)
                sprintf(blurbtxt + strlen(blurbtxt),
                        ", WP");

        printk("%s\n", blurbtxt);

        return cardinfo;
}

static int
sddr09_read_map(struct us_data *us) {

        struct sddr09_card_info *info = (struct sddr09_card_info *) us->extra;
        int numblocks, alloc_len, alloc_blocks;
        int i, j, result;
        unsigned char *buffer, *buffer_end, *ptr;
        unsigned int lba, lbact;

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

        // size of a block is 1 << (blockshift + pageshift) bytes
        // divide into the total capacity to get the number of blocks

        numblocks = info->capacity >> (info->blockshift + info->pageshift);

        // read 64 bytes for every block (actually 1 << CONTROL_SHIFT)
        // but only use a 64 KB buffer
        // buffer size used must be a multiple of (1 << CONTROL_SHIFT)
#define SDDR09_READ_MAP_BUFSZ 65536

        alloc_blocks = min(numblocks, SDDR09_READ_MAP_BUFSZ >> CONTROL_SHIFT);
        alloc_len = (alloc_blocks << CONTROL_SHIFT);
        buffer = kmalloc(alloc_len, GFP_NOIO);
        if (buffer == NULL) {
                printk("sddr09_read_map: out of memory\n");
                result = -1;
                goto done;
        }
        buffer_end = buffer + alloc_len;

#undef SDDR09_READ_MAP_BUFSZ

        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) {
                printk("sddr09_read_map: out of memory\n");
                result = -1;
                goto done;
        }

        for (i = 0; i < numblocks; i++)
                info->lba_to_pba[i] = info->pba_to_lba[i] = UNDEF;

        /*
         * Define lba-pba translation table
         */

        ptr = buffer_end;
        for (i = 0; i < numblocks; i++) {
                ptr += (1 << CONTROL_SHIFT);
                if (ptr >= buffer_end) {
                        unsigned long address;

                        address = i << (info->pageshift + info->blockshift);
                        result = sddr09_read_control(
                                us, address>>1,
                                min(alloc_blocks, numblocks - i),
                                buffer, 0);
                        if (result != USB_STOR_TRANSPORT_GOOD) {
                                result = -1;
                                goto done;
                        }
                        ptr = buffer;
                }

                if (i == 0 || i == 1) {
                        info->pba_to_lba[i] = UNUSABLE;
                        continue;
                }

                /* special PBAs have control field 0^16 */
                for (j = 0; j < 16; j++)
                        if (ptr[j] != 0)
                                goto nonz;
                info->pba_to_lba[i] = UNUSABLE;
                printk("sddr09: PBA %d has no logical mapping\n", i);
                continue;

        nonz:
                /* unwritten PBAs have control field FF^16 */
                for (j = 0; j < 16; j++)
                        if (ptr[j] != 0xff)
                                goto nonff;
                continue;

        nonff:
                /* normal PBAs start with six FFs */
                if (j < 6) {
                        printk("sddr09: PBA %d has no logical mapping: "
                               "reserved area = %02X%02X%02X%02X "
                               "data status %02X block status %02X\n",
                               i, ptr[0], ptr[1], ptr[2], ptr[3],
                               ptr[4], ptr[5]);
                        info->pba_to_lba[i] = UNUSABLE;
                        continue;
                }

                if ((ptr[6] >> 4) != 0x01) {
                        printk("sddr09: PBA %d has invalid address field "
                               "%02X%02X/%02X%02X\n",
                               i, ptr[6], ptr[7], ptr[11], ptr[12]);
                        info->pba_to_lba[i] = UNUSABLE;
                        continue;
                }

                /* check even parity */
                if (parity[ptr[6] ^ ptr[7]]) {
                        printk("sddr09: Bad parity in LBA for block %d"
                               " (%02X %02X)\n", i, ptr[6], ptr[7]);
                        info->pba_to_lba[i] = UNUSABLE;
                        continue;
                }

                lba = short_pack(ptr[7], ptr[6]);
                lba = (lba & 0x07FF) >> 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. This allows for 24 bad
                 * or special physical blocks per zone.
                 */

                if (lba >= 1000) {
                        printk("sddr09: Bad low LBA %d for block %d\n",
                               lba, i);
                        goto possibly_erase;
                }

                lba += 1000*(i/0x400);

                if (info->lba_to_pba[lba] != UNDEF) {
                        printk("sddr09: LBA %d seen for PBA %d and %d\n",
                               lba, info->lba_to_pba[lba], i);
                        goto possibly_erase;
                }

                info->pba_to_lba[i] = lba;
                info->lba_to_pba[lba] = i;
                continue;

        possibly_erase:
                if (erase_bad_lba_entries) {
                        unsigned long address;

                        address = (i << (info->pageshift + info->blockshift));
                        sddr09_erase(us, address>>1);
                        info->pba_to_lba[i] = UNDEF;
                } else
                        info->pba_to_lba[i] = UNUSABLE;
        }

        /*
         * Approximate capacity. This is not entirely correct yet,
         * since a zone with less than 1000 usable pages leads to
         * missing LBAs. Especially if it is the last zone, some
         * LBAs can be past capacity.
         */
        lbact = 0;
        for (i = 0; i < numblocks; i += 1024) {
                int ct = 0;

                for (j = 0; j < 1024 && i+j < numblocks; j++) {
                        if (info->pba_to_lba[i+j] != UNUSABLE) {
                                if (ct >= 1000)
                                        info->pba_to_lba[i+j] = SPARE;
                                else
                                        ct++;
                        }
                }
                lbact += ct;
        }
        info->lbact = lbact;
        US_DEBUGP("Found %d LBA's\n", lbact);
        result = 0;

 done:
        if (result != 0) {
                kfree(info->lba_to_pba);
                kfree(info->pba_to_lba);
                info->lba_to_pba = NULL;
                info->pba_to_lba = NULL;
        }
        kfree(buffer);
        return result;
}

static void
sddr09_card_info_destructor(void *extra) {
        struct sddr09_card_info *info = (struct sddr09_card_info *)extra;

        if (!info)
                return;

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

static void
sddr09_init_card_info(struct us_data *us) {
        if (!us->extra) {
                us->extra = kmalloc(sizeof(struct sddr09_card_info), GFP_NOIO);
                if (us->extra) {
                        memset(us->extra, 0, sizeof(struct sddr09_card_info));
                        us->extra_destructor = sddr09_card_info_destructor;
                }
        }
}

/*
 * This is needed at a very early stage. If this is not listed in the
 * unusual devices list but called from here then LUN 0 of the combo reader
 * is not recognized. But I do not know what precisely these calls do.
 */
int
sddr09_init(struct us_data *us) {
        int result;
        unsigned char *data = us->iobuf;

        result = sddr09_send_command(us, 0x01, USB_DIR_IN, data, 2);
        if (result != USB_STOR_TRANSPORT_GOOD) {
                US_DEBUGP("sddr09_init: send_command fails\n");
                return result;
        }

        US_DEBUGP("SDDR09init: %02X %02X\n", data[0], data[1]);
        // get 07 02

        result = sddr09_send_command(us, 0x08, USB_DIR_IN, data, 2);
        if (result != USB_STOR_TRANSPORT_GOOD) {
                US_DEBUGP("sddr09_init: 2nd send_command fails\n");
                return result;
        }

        US_DEBUGP("SDDR09init: %02X %02X\n", data[0], data[1]);
        // get 07 00

        result = sddr09_request_sense(us, data, 18);
        if (result == USB_STOR_TRANSPORT_GOOD && data[2] != 0) {
                int j;
                for (j=0; j<18; j++)
                        printk(" %02X", data[j]);
                printk("\n");
                // get 70 00 00 00 00 00 00 * 00 00 00 00 00 00
                // 70: current command
                // sense key 0, sense code 0, extd sense code 0
                // additional transfer length * = sizeof(data) - 7
                // Or: 70 00 06 00 00 00 00 0b 00 00 00 00 28 00 00 00 00 00
                // sense key 06, sense code 28: unit attention,
                // not ready to ready transition
        }

        // test unit ready

        return USB_STOR_TRANSPORT_GOOD;         /* not result */
}

/*
 * Transport for the Sandisk SDDR-09
 */
int sddr09_transport(struct scsi_cmnd *srb, struct us_data *us)
{
        static unsigned char sensekey = 0, sensecode = 0;
        static unsigned char havefakesense = 0;
        int result, i;
        unsigned char *ptr = us->iobuf;
        unsigned long capacity;
        unsigned int page, pages;

        struct sddr09_card_info *info;

        static unsigned char inquiry_response[8] = {
                0x00, 0x80, 0x00, 0x02, 0x1F, 0x00, 0x00, 0x00
        };

        /* note: no block descriptor support */
        static unsigned char mode_page_01[19] = {
                0x00, 0x0F, 0x00, 0x0, 0x0, 0x0, 0x00,
                0x01, 0x0A,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
        };

        info = (struct sddr09_card_info *)us->extra;
        if (!info) {
                nand_init_ecc();
                sddr09_init_card_info(us);
                info = (struct sddr09_card_info *)us->extra;
                if (!info)
                        return USB_STOR_TRANSPORT_ERROR;
        }

        if (srb->cmnd[0] == REQUEST_SENSE && havefakesense) {
                /* for a faked command, we have to follow with a faked sense */
                memset(ptr, 0, 18);
                ptr[0] = 0x70;
                ptr[2] = sensekey;
                ptr[7] = 11;
                ptr[12] = sensecode;
                usb_stor_set_xfer_buf(ptr, 18, srb);
                sensekey = sensecode = havefakesense = 0;
                return USB_STOR_TRANSPORT_GOOD;
        }

        havefakesense = 1;

        /* Dummy up a response for INQUIRY since SDDR09 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;
        }

        if (srb->cmnd[0] == READ_CAPACITY) {
                struct nand_flash_dev *cardinfo;

                sddr09_get_wp(us, info);        /* read WP bit */

                cardinfo = sddr09_get_cardinfo(us, info->flags);
                if (!cardinfo) {
                        /* probably no media */
                init_error:
                        sensekey = 0x02;        /* not ready */
                        sensecode = 0x3a;       /* medium not present */
                        return USB_STOR_TRANSPORT_FAILED;
                }

                info->capacity = (1 << cardinfo->chipshift);
                info->pageshift = cardinfo->pageshift;
                info->pagesize = (1 << info->pageshift);
                info->blockshift = cardinfo->blockshift;
                info->blocksize = (1 << info->blockshift);
                info->blockmask = info->blocksize - 1;

                // map initialization, must follow get_cardinfo()
                if (sddr09_read_map(us)) {
                        /* probably out of memory */
                        goto init_error;
                }

                // Report capacity

                capacity = (info->lbact << info->blockshift) - 1;

                ((__be32 *) ptr)[0] = cpu_to_be32(capacity);

                // Report page size

                ((__be32 *) ptr)[1] = cpu_to_be32(info->pagesize);
                usb_stor_set_xfer_buf(ptr, 8, srb);

                return USB_STOR_TRANSPORT_GOOD;
        }

        if (srb->cmnd[0] == MODE_SENSE_10) {
                int modepage = (srb->cmnd[2] & 0x3F);

                /* They ask for the Read/Write error recovery page,
                   or for all pages. */
                /* %% We should check DBD %% */
                if (modepage == 0x01 || modepage == 0x3F) {
                        US_DEBUGP("SDDR09: Dummy up request for "
                                  "mode page 0x%x\n", modepage);

                        memcpy(ptr, mode_page_01, sizeof(mode_page_01));
                        ((__be16*)ptr)[0] = cpu_to_be16(sizeof(mode_page_01) - 2);
                        ptr[3] = (info->flags & SDDR09_WP) ? 0x80 : 0;
                        usb_stor_set_xfer_buf(ptr, sizeof(mode_page_01), srb);
                        return USB_STOR_TRANSPORT_GOOD;
                }

                sensekey = 0x05;        /* illegal request */
                sensecode = 0x24;       /* invalid field in CDB */
                return USB_STOR_TRANSPORT_FAILED;
        }

        if (srb->cmnd[0] == ALLOW_MEDIUM_REMOVAL)
                return USB_STOR_TRANSPORT_GOOD;

        havefakesense = 0;

        if (srb->cmnd[0] == READ_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]);

                US_DEBUGP("READ_10: read page %d pagect %d\n",
                          page, pages);

                return sddr09_read_data(us, page, pages);
        }

        if (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]);

                US_DEBUGP("WRITE_10: write page %d pagect %d\n",
                          page, pages);

                return sddr09_write_data(us, page, pages);
        }

        /* catch-all for all other commands, except
         * pass TEST_UNIT_READY and REQUEST_SENSE through
         */
        if (srb->cmnd[0] != TEST_UNIT_READY &&
            srb->cmnd[0] != REQUEST_SENSE) {
                sensekey = 0x05;        /* illegal request */
                sensecode = 0x20;       /* invalid command */
                havefakesense = 1;
                return USB_STOR_TRANSPORT_FAILED;
        }

        for (; srb->cmd_len<12; srb->cmd_len++)
                srb->cmnd[srb->cmd_len] = 0;

        srb->cmnd[1] = LUNBITS;

        ptr[0] = 0;
        for (i=0; i<12; i++)
                sprintf(ptr+strlen(ptr), "%02X ", srb->cmnd[i]);

        US_DEBUGP("SDDR09: Send control for command %s\n", ptr);

        result = sddr09_send_scsi_command(us, srb->cmnd, 12);
        if (result != USB_STOR_TRANSPORT_GOOD) {
                US_DEBUGP("sddr09_transport: sddr09_send_scsi_command "
                          "returns %d\n", result);
                return result;
        }

        if (srb->request_bufflen == 0)
                return USB_STOR_TRANSPORT_GOOD;

        if (srb->sc_data_direction == DMA_TO_DEVICE ||
            srb->sc_data_direction == DMA_FROM_DEVICE) {
                unsigned int pipe = (srb->sc_data_direction == DMA_TO_DEVICE)
                                ? us->send_bulk_pipe : us->recv_bulk_pipe;

                US_DEBUGP("SDDR09: %s %d bytes\n",
                          (srb->sc_data_direction == DMA_TO_DEVICE) ?
                          "sending" : "receiving",
                          srb->request_bufflen);

                result = usb_stor_bulk_transfer_sg(us, pipe,
                                        srb->request_buffer,
                                        srb->request_bufflen,
                                        srb->use_sg, &srb->resid);

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

        return USB_STOR_TRANSPORT_GOOD;
}