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ide-scsi.c

/*
 * linux/drivers/scsi/ide-scsi.c    Version 0.9       Jul   4, 1999
 *
 * Copyright (C) 1996 - 1999 Gadi Oxman <gadio@netvision.net.il>
 */

/*
 * Emulation of a SCSI host adapter for IDE ATAPI devices.
 *
 * With this driver, one can use the Linux SCSI drivers instead of the
 * native IDE ATAPI drivers.
 *
 * Ver 0.1   Dec  3 96   Initial version.
 * Ver 0.2   Jan 26 97   Fixed bug in cleanup_module() and added emulation
 *                        of MODE_SENSE_6/MODE_SELECT_6 for cdroms. Thanks
 *                        to Janos Farkas for pointing this out.
 *                       Avoid using bitfields in structures for m68k.
 *                       Added Scatter/Gather and DMA support.
 * Ver 0.4   Dec  7 97   Add support for ATAPI PD/CD drives.
 *                       Use variable timeout for each command.
 * Ver 0.5   Jan  2 98   Fix previous PD/CD support.
 *                       Allow disabling of SCSI-6 to SCSI-10 transformation.
 * Ver 0.6   Jan 27 98   Allow disabling of SCSI command translation layer
 *                        for access through /dev/sg.
 *                       Fix MODE_SENSE_6/MODE_SELECT_6/INQUIRY translation.
 * Ver 0.7   Dec 04 98   Ignore commands where lun != 0 to avoid multiple
 *                        detection of devices with CONFIG_SCSI_MULTI_LUN
 * Ver 0.8   Feb 05 99   Optical media need translation too. Reverse 0.7.
 * Ver 0.9   Jul 04 99   Fix a bug in SG_SET_TRANSFORM.
 * Ver 0.91  Jun 10 02   Fix "off by one" error in transforms
 * Ver 0.92  Dec 31 02   Implement new SCSI mid level API
 */

#define IDESCSI_VERSION "0.92"

#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/ioport.h>
#include <linux/blkdev.h>
#include <linux/errno.h>
#include <linux/hdreg.h>
#include <linux/slab.h>
#include <linux/ide.h>
#include <linux/scatterlist.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/bitops.h>

#include <asm/io.h>
#include <asm/uaccess.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_tcq.h>
#include <scsi/sg.h>

#define IDESCSI_DEBUG_LOG           0

typedef struct idescsi_pc_s {
      u8 c[12];                     /* Actual packet bytes */
      int request_transfer;               /* Bytes to transfer */
      int actually_transferred;           /* Bytes actually transferred */
      int buffer_size;              /* Size of our data buffer */
      struct request *rq;                 /* The corresponding request */
      u8 *buffer;                   /* Data buffer */
      u8 *current_position;               /* Pointer into the above buffer */
      struct scatterlist *sg;             /* Scatter gather table */
      unsigned int sg_cnt;                /* Number of entries in sg */
      int b_count;                        /* Bytes transferred from current entry */
      struct scsi_cmnd *scsi_cmd;         /* SCSI command */
      void (*done)(struct scsi_cmnd *);   /* Scsi completion routine */
      unsigned long flags;                /* Status/Action flags */
      unsigned long timeout;              /* Command timeout */
} idescsi_pc_t;

/*
 *    Packet command status bits.
 */
#define PC_DMA_IN_PROGRESS          0     /* 1 while DMA in progress */
#define PC_WRITING                  1     /* Data direction */
#define PC_TIMEDOUT                 3     /* command timed out */
#define PC_DMA_OK             4     /* Use DMA */

/*
 *    SCSI command transformation layer
 */
#define IDESCSI_SG_TRANSFORM        1     /* /dev/sg transformation */

/*
 *    Log flags
 */
#define IDESCSI_LOG_CMD             0     /* Log SCSI commands */

typedef struct ide_scsi_obj {
      ide_drive_t       *drive;
      ide_driver_t            *driver;
      struct gendisk          *disk;
      struct Scsi_Host  *host;

      idescsi_pc_t *pc;             /* Current packet command */
      unsigned long flags;                /* Status/Action flags */
      unsigned long transform;            /* SCSI cmd translation layer */
      unsigned long log;                  /* log flags */
} idescsi_scsi_t;

static DEFINE_MUTEX(idescsi_ref_mutex);
static int idescsi_nocd;                  /* Set by module param to skip cd */

#define ide_scsi_g(disk) \
      container_of((disk)->private_data, struct ide_scsi_obj, driver)

static struct ide_scsi_obj *ide_scsi_get(struct gendisk *disk)
{
      struct ide_scsi_obj *scsi = NULL;

      mutex_lock(&idescsi_ref_mutex);
      scsi = ide_scsi_g(disk);
      if (scsi)
            scsi_host_get(scsi->host);
      mutex_unlock(&idescsi_ref_mutex);
      return scsi;
}

static void ide_scsi_put(struct ide_scsi_obj *scsi)
{
      mutex_lock(&idescsi_ref_mutex);
      scsi_host_put(scsi->host);
      mutex_unlock(&idescsi_ref_mutex);
}

static inline idescsi_scsi_t *scsihost_to_idescsi(struct Scsi_Host *host)
{
      return (idescsi_scsi_t*) (&host[1]);
}

static inline idescsi_scsi_t *drive_to_idescsi(ide_drive_t *ide_drive)
{
      return scsihost_to_idescsi(ide_drive->driver_data);
}

/*
 *    Per ATAPI device status bits.
 */
#define IDESCSI_DRQ_INTERRUPT       0     /* DRQ interrupt device */

/*
 *    ide-scsi requests.
 */
#define IDESCSI_PC_RQ               90

static void idescsi_discard_data (ide_drive_t *drive, unsigned int bcount)
{
      while (bcount--)
            (void) HWIF(drive)->INB(IDE_DATA_REG);
}

static void idescsi_output_zeros (ide_drive_t *drive, unsigned int bcount)
{
      while (bcount--)
            HWIF(drive)->OUTB(0, IDE_DATA_REG);
}

/*
 *    PIO data transfer routines using the scatter gather table.
 */
static void idescsi_input_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsigned int bcount)
{
      int count;
      char *buf;

      while (bcount) {
            count = min(pc->sg->length - pc->b_count, bcount);
            if (PageHighMem(sg_page(pc->sg))) {
                  unsigned long flags;

                  local_irq_save(flags);
                  buf = kmap_atomic(sg_page(pc->sg), KM_IRQ0) +
                              pc->sg->offset;
                  drive->hwif->atapi_input_bytes(drive,
                                    buf + pc->b_count, count);
                  kunmap_atomic(buf - pc->sg->offset, KM_IRQ0);
                  local_irq_restore(flags);
            } else {
                  buf = sg_virt(pc->sg);
                  drive->hwif->atapi_input_bytes(drive,
                                    buf + pc->b_count, count);
            }
            bcount -= count; pc->b_count += count;
            if (pc->b_count == pc->sg->length) {
                  if (!--pc->sg_cnt)
                        break;
                  pc->sg = sg_next(pc->sg);
                  pc->b_count = 0;
            }
      }

      if (bcount) {
            printk (KERN_ERR "ide-scsi: scatter gather table too small, discarding data\n");
            idescsi_discard_data (drive, bcount);
      }
}

static void idescsi_output_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsigned int bcount)
{
      int count;
      char *buf;

      while (bcount) {
            count = min(pc->sg->length - pc->b_count, bcount);
            if (PageHighMem(sg_page(pc->sg))) {
                  unsigned long flags;

                  local_irq_save(flags);
                  buf = kmap_atomic(sg_page(pc->sg), KM_IRQ0) +
                                    pc->sg->offset;
                  drive->hwif->atapi_output_bytes(drive,
                                    buf + pc->b_count, count);
                  kunmap_atomic(buf - pc->sg->offset, KM_IRQ0);
                  local_irq_restore(flags);
            } else {
                  buf = sg_virt(pc->sg);
                  drive->hwif->atapi_output_bytes(drive,
                                    buf + pc->b_count, count);
            }
            bcount -= count; pc->b_count += count;
            if (pc->b_count == pc->sg->length) {
                  if (!--pc->sg_cnt)
                        break;
                  pc->sg = sg_next(pc->sg);
                  pc->b_count = 0;
            }
      }

      if (bcount) {
            printk (KERN_ERR "ide-scsi: scatter gather table too small, padding with zeros\n");
            idescsi_output_zeros (drive, bcount);
      }
}

static void ide_scsi_hex_dump(u8 *data, int len)
{
      print_hex_dump(KERN_CONT, "", DUMP_PREFIX_NONE, 16, 1, data, len, 0);
}

static int idescsi_check_condition(ide_drive_t *drive, struct request *failed_command)
{
      idescsi_scsi_t *scsi = drive_to_idescsi(drive);
      idescsi_pc_t   *pc;
      struct request *rq;
      u8             *buf;

      /* stuff a sense request in front of our current request */
      pc = kzalloc(sizeof(idescsi_pc_t), GFP_ATOMIC);
      rq = kmalloc(sizeof(struct request), GFP_ATOMIC);
      buf = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_ATOMIC);
      if (!pc || !rq || !buf) {
            kfree(buf);
            kfree(rq);
            kfree(pc);
            return -ENOMEM;
      }
      ide_init_drive_cmd(rq);
      rq->special = (char *) pc;
      pc->rq = rq;
      pc->buffer = buf;
      pc->c[0] = REQUEST_SENSE;
      pc->c[4] = pc->request_transfer = pc->buffer_size = SCSI_SENSE_BUFFERSIZE;
      rq->cmd_type = REQ_TYPE_SENSE;
      pc->timeout = jiffies + WAIT_READY;
      /* NOTE! Save the failed packet command in "rq->buffer" */
      rq->buffer = (void *) failed_command->special;
      pc->scsi_cmd = ((idescsi_pc_t *) failed_command->special)->scsi_cmd;
      if (test_bit(IDESCSI_LOG_CMD, &scsi->log)) {
            printk ("ide-scsi: %s: queue cmd = ", drive->name);
            ide_scsi_hex_dump(pc->c, 6);
      }
      rq->rq_disk = scsi->disk;
      return ide_do_drive_cmd(drive, rq, ide_preempt);
}

static int idescsi_end_request(ide_drive_t *, int, int);

static ide_startstop_t
idescsi_atapi_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
{
      if (HWIF(drive)->INB(IDE_STATUS_REG) & (BUSY_STAT|DRQ_STAT))
            /* force an abort */
            HWIF(drive)->OUTB(WIN_IDLEIMMEDIATE,IDE_COMMAND_REG);

      rq->errors++;

      idescsi_end_request(drive, 0, 0);

      return ide_stopped;
}

static ide_startstop_t
idescsi_atapi_abort(ide_drive_t *drive, struct request *rq)
{
#if IDESCSI_DEBUG_LOG
      printk(KERN_WARNING "idescsi_atapi_abort called for %lu\n",
                  ((idescsi_pc_t *) rq->special)->scsi_cmd->serial_number);
#endif
      rq->errors |= ERROR_MAX;

      idescsi_end_request(drive, 0, 0);

      return ide_stopped;
}

static int idescsi_end_request (ide_drive_t *drive, int uptodate, int nrsecs)
{
      idescsi_scsi_t *scsi = drive_to_idescsi(drive);
      struct request *rq = HWGROUP(drive)->rq;
      idescsi_pc_t *pc = (idescsi_pc_t *) rq->special;
      int log = test_bit(IDESCSI_LOG_CMD, &scsi->log);
      struct Scsi_Host *host;
      int errors = rq->errors;
      unsigned long flags;

      if (!blk_special_request(rq) && !blk_sense_request(rq)) {
            ide_end_request(drive, uptodate, nrsecs);
            return 0;
      }
      ide_end_drive_cmd (drive, 0, 0);
      if (blk_sense_request(rq)) {
            idescsi_pc_t *opc = (idescsi_pc_t *) rq->buffer;
            if (log) {
                  printk ("ide-scsi: %s: wrap up check %lu, rst = ", drive->name, opc->scsi_cmd->serial_number);
                  ide_scsi_hex_dump(pc->buffer, 16);
            }
            memcpy((void *) opc->scsi_cmd->sense_buffer, pc->buffer, SCSI_SENSE_BUFFERSIZE);
            kfree(pc->buffer);
            kfree(pc);
            kfree(rq);
            pc = opc;
            rq = pc->rq;
            pc->scsi_cmd->result = (CHECK_CONDITION << 1) |
                              ((test_bit(PC_TIMEDOUT, &pc->flags)?DID_TIME_OUT:DID_OK) << 16);
      } else if (test_bit(PC_TIMEDOUT, &pc->flags)) {
            if (log)
                  printk (KERN_WARNING "ide-scsi: %s: timed out for %lu\n",
                              drive->name, pc->scsi_cmd->serial_number);
            pc->scsi_cmd->result = DID_TIME_OUT << 16;
      } else if (errors >= ERROR_MAX) {
            pc->scsi_cmd->result = DID_ERROR << 16;
            if (log)
                  printk ("ide-scsi: %s: I/O error for %lu\n", drive->name, pc->scsi_cmd->serial_number);
      } else if (errors) {
            if (log)
                  printk ("ide-scsi: %s: check condition for %lu\n", drive->name, pc->scsi_cmd->serial_number);
            if (!idescsi_check_condition(drive, rq))
                  /* we started a request sense, so we'll be back, exit for now */
                  return 0;
            pc->scsi_cmd->result = (CHECK_CONDITION << 1) | (DID_OK << 16);
      } else {
            pc->scsi_cmd->result = DID_OK << 16;
      }
      host = pc->scsi_cmd->device->host;
      spin_lock_irqsave(host->host_lock, flags);
      pc->done(pc->scsi_cmd);
      spin_unlock_irqrestore(host->host_lock, flags);
      kfree(pc);
      kfree(rq);
      scsi->pc = NULL;
      return 0;
}

static inline unsigned long get_timeout(idescsi_pc_t *pc)
{
      return max_t(unsigned long, WAIT_CMD, pc->timeout - jiffies);
}

static int idescsi_expiry(ide_drive_t *drive)
{
      idescsi_scsi_t *scsi = drive_to_idescsi(drive);
      idescsi_pc_t   *pc   = scsi->pc;

#if IDESCSI_DEBUG_LOG
      printk(KERN_WARNING "idescsi_expiry called for %lu at %lu\n", pc->scsi_cmd->serial_number, jiffies);
#endif
      set_bit(PC_TIMEDOUT, &pc->flags);

      return 0;                           /* we do not want the ide subsystem to retry */
}

/*
 *    Our interrupt handler.
 */
static ide_startstop_t idescsi_pc_intr (ide_drive_t *drive)
{
      idescsi_scsi_t *scsi = drive_to_idescsi(drive);
      idescsi_pc_t *pc=scsi->pc;
      struct request *rq = pc->rq;
      atapi_bcount_t bcount;
      atapi_status_t status;
      atapi_ireason_t ireason;
      atapi_feature_t feature;

      unsigned int temp;

#if IDESCSI_DEBUG_LOG
      printk (KERN_INFO "ide-scsi: Reached idescsi_pc_intr interrupt handler\n");
#endif /* IDESCSI_DEBUG_LOG */

      if (test_bit(PC_TIMEDOUT, &pc->flags)){
#if IDESCSI_DEBUG_LOG
            printk(KERN_WARNING "idescsi_pc_intr: got timed out packet  %lu at %lu\n",
                        pc->scsi_cmd->serial_number, jiffies);
#endif
            /* end this request now - scsi should retry it*/
            idescsi_end_request (drive, 1, 0);
            return ide_stopped;
      }
      if (test_and_clear_bit (PC_DMA_IN_PROGRESS, &pc->flags)) {
#if IDESCSI_DEBUG_LOG
            printk ("ide-scsi: %s: DMA complete\n", drive->name);
#endif /* IDESCSI_DEBUG_LOG */
            pc->actually_transferred=pc->request_transfer;
            (void) HWIF(drive)->ide_dma_end(drive);
      }

      feature.all = 0;
      /* Clear the interrupt */
      status.all = HWIF(drive)->INB(IDE_STATUS_REG);

      if (!status.b.drq) {
            /* No more interrupts */
            if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
                  printk (KERN_INFO "Packet command completed, %d bytes transferred\n", pc->actually_transferred);
            local_irq_enable_in_hardirq();
            if (status.b.check)
                  rq->errors++;
            idescsi_end_request (drive, 1, 0);
            return ide_stopped;
      }
      bcount.b.low      = HWIF(drive)->INB(IDE_BCOUNTL_REG);
      bcount.b.high     = HWIF(drive)->INB(IDE_BCOUNTH_REG);
      ireason.all = HWIF(drive)->INB(IDE_IREASON_REG);

      if (ireason.b.cod) {
            printk(KERN_ERR "ide-scsi: CoD != 0 in idescsi_pc_intr\n");
            return ide_do_reset (drive);
      }
      if (ireason.b.io) {
            temp = pc->actually_transferred + bcount.all;
            if (temp > pc->request_transfer) {
                  if (temp > pc->buffer_size) {
                        printk(KERN_ERR "ide-scsi: The scsi wants to "
                              "send us more data than expected "
                              "- discarding data\n");
                        temp = pc->buffer_size - pc->actually_transferred;
                        if (temp) {
                              clear_bit(PC_WRITING, &pc->flags);
                              if (pc->sg)
                                    idescsi_input_buffers(drive, pc, temp);
                              else
                                    drive->hwif->atapi_input_bytes(drive, pc->current_position, temp);
                              printk(KERN_ERR "ide-scsi: transferred %d of %d bytes\n", temp, bcount.all);
                        }
                        pc->actually_transferred += temp;
                        pc->current_position += temp;
                        idescsi_discard_data(drive, bcount.all - temp);
                        ide_set_handler(drive, &idescsi_pc_intr, get_timeout(pc), idescsi_expiry);
                        return ide_started;
                  }
#if IDESCSI_DEBUG_LOG
                  printk (KERN_NOTICE "ide-scsi: The scsi wants to send us more data than expected - allowing transfer\n");
#endif /* IDESCSI_DEBUG_LOG */
            }
      }
      if (ireason.b.io) {
            clear_bit(PC_WRITING, &pc->flags);
            if (pc->sg)
                  idescsi_input_buffers(drive, pc, bcount.all);
            else
                  HWIF(drive)->atapi_input_bytes(drive, pc->current_position, bcount.all);
      } else {
            set_bit(PC_WRITING, &pc->flags);
            if (pc->sg)
                  idescsi_output_buffers (drive, pc, bcount.all);
            else
                  HWIF(drive)->atapi_output_bytes(drive, pc->current_position, bcount.all);
      }
      /* Update the current position */
      pc->actually_transferred += bcount.all;
      pc->current_position += bcount.all;

      /* And set the interrupt handler again */
      ide_set_handler(drive, &idescsi_pc_intr, get_timeout(pc), idescsi_expiry);
      return ide_started;
}

static ide_startstop_t idescsi_transfer_pc(ide_drive_t *drive)
{
      ide_hwif_t *hwif = drive->hwif;
      idescsi_scsi_t *scsi = drive_to_idescsi(drive);
      idescsi_pc_t *pc = scsi->pc;
      atapi_ireason_t ireason;
      ide_startstop_t startstop;

      if (ide_wait_stat(&startstop,drive,DRQ_STAT,BUSY_STAT,WAIT_READY)) {
            printk(KERN_ERR "ide-scsi: Strange, packet command "
                  "initiated yet DRQ isn't asserted\n");
            return startstop;
      }
      ireason.all = HWIF(drive)->INB(IDE_IREASON_REG);
      if (!ireason.b.cod || ireason.b.io) {
            printk(KERN_ERR "ide-scsi: (IO,CoD) != (0,1) while "
                        "issuing a packet command\n");
            return ide_do_reset (drive);
      }
      BUG_ON(HWGROUP(drive)->handler != NULL);
      /* Set the interrupt routine */
      ide_set_handler(drive, &idescsi_pc_intr, get_timeout(pc), idescsi_expiry);
      /* Send the actual packet */
      drive->hwif->atapi_output_bytes(drive, scsi->pc->c, 12);
      if (test_bit (PC_DMA_OK, &pc->flags)) {
            set_bit (PC_DMA_IN_PROGRESS, &pc->flags);
            hwif->dma_start(drive);
      }
      return ide_started;
}

static inline int idescsi_set_direction(idescsi_pc_t *pc)
{
      switch (pc->c[0]) {
            case READ_6: case READ_10: case READ_12:
                  clear_bit(PC_WRITING, &pc->flags);
                  return 0;
            case WRITE_6: case WRITE_10: case WRITE_12:
                  set_bit(PC_WRITING, &pc->flags);
                  return 0;
            default:
                  return 1;
      }
}

static int idescsi_map_sg(ide_drive_t *drive, idescsi_pc_t *pc)
{
      ide_hwif_t *hwif = drive->hwif;
      struct scatterlist *sg, *scsi_sg;
      int segments;

      if (!pc->request_transfer || pc->request_transfer % 1024)
            return 1;

      if (idescsi_set_direction(pc))
            return 1;

      sg = hwif->sg_table;
      scsi_sg = scsi_sglist(pc->scsi_cmd);
      segments = scsi_sg_count(pc->scsi_cmd);

      if (segments > hwif->sg_max_nents)
            return 1;

      hwif->sg_nents = segments;
      memcpy(sg, scsi_sg, sizeof(*sg) * segments);

      return 0;
}

/*
 *    Issue a packet command
 */
static ide_startstop_t idescsi_issue_pc (ide_drive_t *drive, idescsi_pc_t *pc)
{
      idescsi_scsi_t *scsi = drive_to_idescsi(drive);
      ide_hwif_t *hwif = drive->hwif;
      atapi_feature_t feature;
      atapi_bcount_t bcount;

      scsi->pc=pc;                                          /* Set the current packet command */
      pc->actually_transferred=0;                           /* We haven't transferred any data yet */
      pc->current_position=pc->buffer;
      bcount.all = min(pc->request_transfer, 63 * 1024);          /* Request to transfer the entire buffer at once */

      feature.all = 0;
      if (drive->using_dma && !idescsi_map_sg(drive, pc)) {
            hwif->sg_mapped = 1;
            feature.b.dma = !hwif->dma_setup(drive);
            hwif->sg_mapped = 0;
      }

      SELECT_DRIVE(drive);
      if (IDE_CONTROL_REG)
            HWIF(drive)->OUTB(drive->ctl, IDE_CONTROL_REG);

      HWIF(drive)->OUTB(feature.all, IDE_FEATURE_REG);
      HWIF(drive)->OUTB(bcount.b.high, IDE_BCOUNTH_REG);
      HWIF(drive)->OUTB(bcount.b.low, IDE_BCOUNTL_REG);

      if (feature.b.dma)
            set_bit(PC_DMA_OK, &pc->flags);

      if (test_bit(IDESCSI_DRQ_INTERRUPT, &scsi->flags)) {
            BUG_ON(HWGROUP(drive)->handler != NULL);
            ide_set_handler(drive, &idescsi_transfer_pc,
                        get_timeout(pc), idescsi_expiry);
            /* Issue the packet command */
            HWIF(drive)->OUTB(WIN_PACKETCMD, IDE_COMMAND_REG);
            return ide_started;
      } else {
            /* Issue the packet command */
            HWIF(drive)->OUTB(WIN_PACKETCMD, IDE_COMMAND_REG);
            return idescsi_transfer_pc(drive);
      }
}

/*
 *    idescsi_do_request is our request handling function.
 */
static ide_startstop_t idescsi_do_request (ide_drive_t *drive, struct request *rq, sector_t block)
{
#if IDESCSI_DEBUG_LOG
      printk (KERN_INFO "dev: %s, cmd: %x, errors: %d\n", rq->rq_disk->disk_name,rq->cmd[0],rq->errors);
      printk (KERN_INFO "sector: %ld, nr_sectors: %ld, current_nr_sectors: %d\n",rq->sector,rq->nr_sectors,rq->current_nr_sectors);
#endif /* IDESCSI_DEBUG_LOG */

      if (blk_sense_request(rq) || blk_special_request(rq)) {
            return idescsi_issue_pc (drive, (idescsi_pc_t *) rq->special);
      }
      blk_dump_rq_flags(rq, "ide-scsi: unsup command");
      idescsi_end_request (drive, 0, 0);
      return ide_stopped;
}

#ifdef CONFIG_IDE_PROC_FS
static void idescsi_add_settings(ide_drive_t *drive)
{
      idescsi_scsi_t *scsi = drive_to_idescsi(drive);

/*
 *                drive setting name      read/write  data type   min   max   mul_factor  div_factor  data pointer            set function
 */
      ide_add_setting(drive,  "bios_cyl", SETTING_RW, TYPE_INT,   0,    1023, 1,          1,          &drive->bios_cyl, NULL);
      ide_add_setting(drive,  "bios_head",      SETTING_RW, TYPE_BYTE,  0,    255,  1,          1,          &drive->bios_head,      NULL);
      ide_add_setting(drive,  "bios_sect",      SETTING_RW, TYPE_BYTE,  0,    63,   1,          1,          &drive->bios_sect,      NULL);
      ide_add_setting(drive,  "transform",      SETTING_RW, TYPE_INT,   0,    3,    1,          1,          &scsi->transform, NULL);
      ide_add_setting(drive,  "log",            SETTING_RW, TYPE_INT,   0,    1,    1,          1,          &scsi->log,       NULL);
}
#else
static inline void idescsi_add_settings(ide_drive_t *drive) { ; }
#endif

/*
 *    Driver initialization.
 */
static void idescsi_setup (ide_drive_t *drive, idescsi_scsi_t *scsi)
{
      if (drive->id && (drive->id->config & 0x0060) == 0x20)
            set_bit (IDESCSI_DRQ_INTERRUPT, &scsi->flags);
      clear_bit(IDESCSI_SG_TRANSFORM, &scsi->transform);
#if IDESCSI_DEBUG_LOG
      set_bit(IDESCSI_LOG_CMD, &scsi->log);
#endif /* IDESCSI_DEBUG_LOG */
      idescsi_add_settings(drive);
}

static void ide_scsi_remove(ide_drive_t *drive)
{
      struct Scsi_Host *scsihost = drive->driver_data;
      struct ide_scsi_obj *scsi = scsihost_to_idescsi(scsihost);
      struct gendisk *g = scsi->disk;

      scsi_remove_host(scsihost);
      ide_proc_unregister_driver(drive, scsi->driver);

      ide_unregister_region(g);

      drive->driver_data = NULL;
      g->private_data = NULL;
      put_disk(g);

      ide_scsi_put(scsi);
}

static int ide_scsi_probe(ide_drive_t *);

#ifdef CONFIG_IDE_PROC_FS
static ide_proc_entry_t idescsi_proc[] = {
      { "capacity", S_IFREG|S_IRUGO, proc_ide_read_capacity, NULL },
      { NULL, 0, NULL, NULL }
};
#endif

static ide_driver_t idescsi_driver = {
      .gen_driver = {
            .owner            = THIS_MODULE,
            .name       = "ide-scsi",
            .bus        = &ide_bus_type,
      },
      .probe                  = ide_scsi_probe,
      .remove                 = ide_scsi_remove,
      .version          = IDESCSI_VERSION,
      .media                  = ide_scsi,
      .supports_dsc_overlap   = 0,
      .do_request       = idescsi_do_request,
      .end_request            = idescsi_end_request,
      .error                  = idescsi_atapi_error,
      .abort                  = idescsi_atapi_abort,
#ifdef CONFIG_IDE_PROC_FS
      .proc             = idescsi_proc,
#endif
};

static int idescsi_ide_open(struct inode *inode, struct file *filp)
{
      struct gendisk *disk = inode->i_bdev->bd_disk;
      struct ide_scsi_obj *scsi;

      if (!(scsi = ide_scsi_get(disk)))
            return -ENXIO;

      return 0;
}

static int idescsi_ide_release(struct inode *inode, struct file *filp)
{
      struct gendisk *disk = inode->i_bdev->bd_disk;
      struct ide_scsi_obj *scsi = ide_scsi_g(disk);

      ide_scsi_put(scsi);

      return 0;
}

static int idescsi_ide_ioctl(struct inode *inode, struct file *file,
                  unsigned int cmd, unsigned long arg)
{
      struct block_device *bdev = inode->i_bdev;
      struct ide_scsi_obj *scsi = ide_scsi_g(bdev->bd_disk);
      return generic_ide_ioctl(scsi->drive, file, bdev, cmd, arg);
}

static struct block_device_operations idescsi_ops = {
      .owner            = THIS_MODULE,
      .open       = idescsi_ide_open,
      .release    = idescsi_ide_release,
      .ioctl            = idescsi_ide_ioctl,
};

static int idescsi_slave_configure(struct scsi_device * sdp)
{
      /* Configure detected device */
      sdp->use_10_for_rw = 1;
      sdp->use_10_for_ms = 1;
      scsi_adjust_queue_depth(sdp, MSG_SIMPLE_TAG, sdp->host->cmd_per_lun);
      return 0;
}

static const char *idescsi_info (struct Scsi_Host *host)
{
      return "SCSI host adapter emulation for IDE ATAPI devices";
}

static int idescsi_ioctl (struct scsi_device *dev, int cmd, void __user *arg)
{
      idescsi_scsi_t *scsi = scsihost_to_idescsi(dev->host);

      if (cmd == SG_SET_TRANSFORM) {
            if (arg)
                  set_bit(IDESCSI_SG_TRANSFORM, &scsi->transform);
            else
                  clear_bit(IDESCSI_SG_TRANSFORM, &scsi->transform);
            return 0;
      } else if (cmd == SG_GET_TRANSFORM)
            return put_user(test_bit(IDESCSI_SG_TRANSFORM, &scsi->transform), (int __user *) arg);
      return -EINVAL;
}

static int idescsi_queue (struct scsi_cmnd *cmd,
            void (*done)(struct scsi_cmnd *))
{
      struct Scsi_Host *host = cmd->device->host;
      idescsi_scsi_t *scsi = scsihost_to_idescsi(host);
      ide_drive_t *drive = scsi->drive;
      struct request *rq = NULL;
      idescsi_pc_t *pc = NULL;

      if (!drive) {
            scmd_printk (KERN_ERR, cmd, "drive not present\n");
            goto abort;
      }
      scsi = drive_to_idescsi(drive);
      pc = kmalloc (sizeof (idescsi_pc_t), GFP_ATOMIC);
      rq = kmalloc (sizeof (struct request), GFP_ATOMIC);
      if (rq == NULL || pc == NULL) {
            printk (KERN_ERR "ide-scsi: %s: out of memory\n", drive->name);
            goto abort;
      }

      memset (pc->c, 0, 12);
      pc->flags = 0;
      pc->rq = rq;
      memcpy (pc->c, cmd->cmnd, cmd->cmd_len);
      pc->buffer = NULL;
      pc->sg = scsi_sglist(cmd);
      pc->sg_cnt = scsi_sg_count(cmd);
      pc->b_count = 0;
      pc->request_transfer = pc->buffer_size = scsi_bufflen(cmd);
      pc->scsi_cmd = cmd;
      pc->done = done;
      pc->timeout = jiffies + cmd->timeout_per_command;

      if (test_bit(IDESCSI_LOG_CMD, &scsi->log)) {
            printk ("ide-scsi: %s: que %lu, cmd = ", drive->name, cmd->serial_number);
            ide_scsi_hex_dump(cmd->cmnd, cmd->cmd_len);
            if (memcmp(pc->c, cmd->cmnd, cmd->cmd_len)) {
                  printk ("ide-scsi: %s: que %lu, tsl = ", drive->name, cmd->serial_number);
                  ide_scsi_hex_dump(pc->c, 12);
            }
      }

      ide_init_drive_cmd (rq);
      rq->special = (char *) pc;
      rq->cmd_type = REQ_TYPE_SPECIAL;
      spin_unlock_irq(host->host_lock);
      rq->rq_disk = scsi->disk;
      (void) ide_do_drive_cmd (drive, rq, ide_end);
      spin_lock_irq(host->host_lock);
      return 0;
abort:
      kfree (pc);
      kfree (rq);
      cmd->result = DID_ERROR << 16;
      done(cmd);
      return 0;
}

static int idescsi_eh_abort (struct scsi_cmnd *cmd)
{
      idescsi_scsi_t *scsi  = scsihost_to_idescsi(cmd->device->host);
      ide_drive_t    *drive = scsi->drive;
      int         busy;
      int             ret   = FAILED;

      /* In idescsi_eh_abort we try to gently pry our command from the ide subsystem */

      if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
            printk (KERN_WARNING "ide-scsi: abort called for %lu\n", cmd->serial_number);

      if (!drive) {
            printk (KERN_WARNING "ide-scsi: Drive not set in idescsi_eh_abort\n");
            WARN_ON(1);
            goto no_drive;
      }

      /* First give it some more time, how much is "right" is hard to say :-( */

      busy = ide_wait_not_busy(HWIF(drive), 100);     /* FIXME - uses mdelay which causes latency? */
      if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
            printk (KERN_WARNING "ide-scsi: drive did%s become ready\n", busy?" not":"");

      spin_lock_irq(&ide_lock);

      /* If there is no pc running we're done (our interrupt took care of it) */
      if (!scsi->pc) {
            ret = SUCCESS;
            goto ide_unlock;
      }

      /* It's somewhere in flight. Does ide subsystem agree? */
      if (scsi->pc->scsi_cmd->serial_number == cmd->serial_number && !busy &&
          elv_queue_empty(drive->queue) && HWGROUP(drive)->rq != scsi->pc->rq) {
            /*
             * FIXME - not sure this condition can ever occur
             */
            printk (KERN_ERR "ide-scsi: cmd aborted!\n");

            if (blk_sense_request(scsi->pc->rq))
                  kfree(scsi->pc->buffer);
            kfree(scsi->pc->rq);
            kfree(scsi->pc);
            scsi->pc = NULL;

            ret = SUCCESS;
      }

ide_unlock:
      spin_unlock_irq(&ide_lock);
no_drive:
      if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
            printk (KERN_WARNING "ide-scsi: abort returns %s\n", ret == SUCCESS?"success":"failed");

      return ret;
}

static int idescsi_eh_reset (struct scsi_cmnd *cmd)
{
      struct request *req;
      idescsi_scsi_t *scsi  = scsihost_to_idescsi(cmd->device->host);
      ide_drive_t    *drive = scsi->drive;
      int             ready = 0;
      int             ret   = SUCCESS;

      /* In idescsi_eh_reset we forcefully remove the command from the ide subsystem and reset the device. */

      if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
            printk (KERN_WARNING "ide-scsi: reset called for %lu\n", cmd->serial_number);

      if (!drive) {
            printk (KERN_WARNING "ide-scsi: Drive not set in idescsi_eh_reset\n");
            WARN_ON(1);
            return FAILED;
      }

      spin_lock_irq(cmd->device->host->host_lock);
      spin_lock(&ide_lock);

      if (!scsi->pc || (req = scsi->pc->rq) != HWGROUP(drive)->rq || !HWGROUP(drive)->handler) {
            printk (KERN_WARNING "ide-scsi: No active request in idescsi_eh_reset\n");
            spin_unlock(&ide_lock);
            spin_unlock_irq(cmd->device->host->host_lock);
            return FAILED;
      }

      /* kill current request */
      blkdev_dequeue_request(req);
      end_that_request_last(req, 0);
      if (blk_sense_request(req))
            kfree(scsi->pc->buffer);
      kfree(scsi->pc);
      scsi->pc = NULL;
      kfree(req);

      /* now nuke the drive queue */
      while ((req = elv_next_request(drive->queue))) {
            blkdev_dequeue_request(req);
            end_that_request_last(req, 0);
      }

      HWGROUP(drive)->rq = NULL;
      HWGROUP(drive)->handler = NULL;
      HWGROUP(drive)->busy = 1;           /* will set this to zero when ide reset finished */
      spin_unlock(&ide_lock);

      ide_do_reset(drive);

      /* ide_do_reset starts a polling handler which restarts itself every 50ms until the reset finishes */

      do {
            spin_unlock_irq(cmd->device->host->host_lock);
            msleep(50);
            spin_lock_irq(cmd->device->host->host_lock);
      } while ( HWGROUP(drive)->handler );

      ready = drive_is_ready(drive);
      HWGROUP(drive)->busy--;
      if (!ready) {
            printk (KERN_ERR "ide-scsi: reset failed!\n");
            ret = FAILED;
      }

      spin_unlock_irq(cmd->device->host->host_lock);
      return ret;
}

static int idescsi_bios(struct scsi_device *sdev, struct block_device *bdev,
            sector_t capacity, int *parm)
{
      idescsi_scsi_t *idescsi = scsihost_to_idescsi(sdev->host);
      ide_drive_t *drive = idescsi->drive;

      if (drive->bios_cyl && drive->bios_head && drive->bios_sect) {
            parm[0] = drive->bios_head;
            parm[1] = drive->bios_sect;
            parm[2] = drive->bios_cyl;
      }
      return 0;
}

static struct scsi_host_template idescsi_template = {
      .module                 = THIS_MODULE,
      .name             = "idescsi",
      .info             = idescsi_info,
      .slave_configure        = idescsi_slave_configure,
      .ioctl                  = idescsi_ioctl,
      .queuecommand           = idescsi_queue,
      .eh_abort_handler = idescsi_eh_abort,
      .eh_host_reset_handler  = idescsi_eh_reset,
      .bios_param       = idescsi_bios,
      .can_queue        = 40,
      .this_id          = -1,
      .sg_tablesize           = 256,
      .cmd_per_lun            = 5,
      .max_sectors            = 128,
      .use_clustering         = DISABLE_CLUSTERING,
      .emulated         = 1,
      .proc_name        = "ide-scsi",
};

static int ide_scsi_probe(ide_drive_t *drive)
{
      idescsi_scsi_t *idescsi;
      struct Scsi_Host *host;
      struct gendisk *g;
      static int warned;
      int err = -ENOMEM;

      if (!warned && drive->media == ide_cdrom) {
            printk(KERN_WARNING "ide-scsi is deprecated for cd burning! Use ide-cd and give dev=/dev/hdX as device\n");
            warned = 1;
      }

      if (idescsi_nocd && drive->media == ide_cdrom)
            return -ENODEV;

      if (!strstr("ide-scsi", drive->driver_req) ||
          !drive->present ||
          drive->media == ide_disk ||
          !(host = scsi_host_alloc(&idescsi_template,sizeof(idescsi_scsi_t))))
            return -ENODEV;

      g = alloc_disk(1 << PARTN_BITS);
      if (!g)
            goto out_host_put;

      ide_init_disk(g, drive);

      host->max_id = 1;

#if IDESCSI_DEBUG_LOG
      if (drive->id->last_lun)
            printk(KERN_NOTICE "%s: id->last_lun=%u\n", drive->name, drive->id->last_lun);
#endif
      if ((drive->id->last_lun & 0x7) != 7)
            host->max_lun = (drive->id->last_lun & 0x7) + 1;
      else
            host->max_lun = 1;

      drive->driver_data = host;
      idescsi = scsihost_to_idescsi(host);
      idescsi->drive = drive;
      idescsi->driver = &idescsi_driver;
      idescsi->host = host;
      idescsi->disk = g;
      g->private_data = &idescsi->driver;
      ide_proc_register_driver(drive, &idescsi_driver);
      err = 0;
      idescsi_setup(drive, idescsi);
      g->fops = &idescsi_ops;
      ide_register_region(g);
      err = scsi_add_host(host, &drive->gendev);
      if (!err) {
            scsi_scan_host(host);
            return 0;
      }
      /* fall through on error */
      ide_unregister_region(g);
      ide_proc_unregister_driver(drive, &idescsi_driver);

      put_disk(g);
out_host_put:
      scsi_host_put(host);
      return err;
}

static int __init init_idescsi_module(void)
{
      return driver_register(&idescsi_driver.gen_driver);
}

static void __exit exit_idescsi_module(void)
{
      driver_unregister(&idescsi_driver.gen_driver);
}

module_param(idescsi_nocd, int, 0600);
MODULE_PARM_DESC(idescsi_nocd, "Disable handling of CD-ROMs so they may be driven by ide-cd");
module_init(init_idescsi_module);
module_exit(exit_idescsi_module);
MODULE_LICENSE("GPL");

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