ClabureDB: Classified Bug-Reports Database

   /*
    *        IDE I/O functions
    *
    *        Basic PIO and command management functionality.
    *
    * This code was split off from ide.c. See ide.c for history and original
    * copyrights.
    *
    * 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.
   *
   * For the avoidance of doubt the "preferred form" of this code is one which
   * is in an open non patent encumbered format. Where cryptographic key signing
   * forms part of the process of creating an executable the information
   * including keys needed to generate an equivalently functional executable
   * are deemed to be part of the source code.
   */
   
   
  #include <linux/module.h>
  #include <linux/types.h>
  #include <linux/string.h>
  #include <linux/kernel.h>
  #include <linux/timer.h>
  #include <linux/mm.h>
  #include <linux/interrupt.h>
  #include <linux/major.h>
  #include <linux/errno.h>
  #include <linux/genhd.h>
  #include <linux/blkpg.h>
  #include <linux/slab.h>
  #include <linux/init.h>
  #include <linux/pci.h>
  #include <linux/delay.h>
  #include <linux/ide.h>
  #include <linux/hdreg.h>
  #include <linux/completion.h>
  #include <linux/reboot.h>
  #include <linux/cdrom.h>
  #include <linux/seq_file.h>
  #include <linux/device.h>
  #include <linux/kmod.h>
  #include <linux/scatterlist.h>
  #include <linux/bitops.h>
  
  #include <asm/byteorder.h>
  #include <asm/irq.h>
  #include <asm/uaccess.h>
  #include <asm/io.h>
  
  static int __ide_end_request(ide_drive_t *drive, struct request *rq,
                               int uptodate, unsigned int nr_bytes, int dequeue)
  {
          int ret = 1;
          int error = 0;
  
          if (uptodate <= 0)
                  error = uptodate ? uptodate : -EIO;
  
          /*
           * if failfast is set on a request, override number of sectors and
           * complete the whole request right now
           */
          if (blk_noretry_request(rq) && error)
                  nr_bytes = rq->hard_nr_sectors << 9;
  
          if (!blk_fs_request(rq) && error && !rq->errors)
                  rq->errors = -EIO;
  
          /*
           * decide whether to reenable DMA -- 3 is a random magic for now,
           * if we DMA timeout more than 3 times, just stay in PIO
           */
          if ((drive->dev_flags & IDE_DFLAG_DMA_PIO_RETRY) &&
              drive->retry_pio <= 3) {
                  drive->dev_flags &= ~IDE_DFLAG_DMA_PIO_RETRY;
                  ide_dma_on(drive);
          }
  
          if (!__blk_end_request(rq, error, nr_bytes)) {
                  if (dequeue)
                          HWGROUP(drive)->rq = NULL;
                  ret = 0;
          }
  
          return ret;
  }
  
  /**
   *        ide_end_request                -        complete an IDE I/O
   *        @drive: IDE device for the I/O
   *        @uptodate:
  *        @nr_sectors: number of sectors completed
  *
  *        This is our end_request wrapper function. We complete the I/O
  *        update random number input and dequeue the request, which if
  *        it was tagged may be out of order.
  */
 
 int ide_end_request (ide_drive_t *drive, int uptodate, int nr_sectors)
 {
         unsigned int nr_bytes = nr_sectors << 9;
         struct request *rq;
         unsigned long flags;
         int ret = 1;
 
         /*
          * room for locking improvements here, the calls below don't
          * need the queue lock held at all
          */
         spin_lock_irqsave(&ide_lock, flags);
         rq = HWGROUP(drive)->rq;
 
         if (!nr_bytes) {
                 if (blk_pc_request(rq))
                         nr_bytes = rq->data_len;
                 else
                         nr_bytes = rq->hard_cur_sectors << 9;
         }
 
         ret = __ide_end_request(drive, rq, uptodate, nr_bytes, 1);
 
         spin_unlock_irqrestore(&ide_lock, flags);
         return ret;
 }
 EXPORT_SYMBOL(ide_end_request);
 
 static void ide_complete_power_step(ide_drive_t *drive, struct request *rq)
 {
         struct request_pm_state *pm = rq->data;
 
 #ifdef DEBUG_PM
         printk(KERN_INFO "%s: complete_power_step(step: %d)\n",
                 drive->name, pm->pm_step);
 #endif
         if (drive->media != ide_disk)
                 return;
 
         switch (pm->pm_step) {
         case IDE_PM_FLUSH_CACHE:        /* Suspend step 1 (flush cache) */
                 if (pm->pm_state == PM_EVENT_FREEZE)
                         pm->pm_step = IDE_PM_COMPLETED;
                 else
                         pm->pm_step = IDE_PM_STANDBY;
                 break;
         case IDE_PM_STANDBY:                /* Suspend step 2 (standby) */
                 pm->pm_step = IDE_PM_COMPLETED;
                 break;
         case IDE_PM_RESTORE_PIO:        /* Resume step 1 (restore PIO) */
                 pm->pm_step = IDE_PM_IDLE;
                 break;
         case IDE_PM_IDLE:                /* Resume step 2 (idle)*/
                 pm->pm_step = IDE_PM_RESTORE_DMA;
                 break;
         }
 }
 
 static ide_startstop_t ide_start_power_step(ide_drive_t *drive, struct request *rq)
 {
         struct request_pm_state *pm = rq->data;
         ide_task_t *args = rq->special;
 
         memset(args, 0, sizeof(*args));
 
         switch (pm->pm_step) {
         case IDE_PM_FLUSH_CACHE:        /* Suspend step 1 (flush cache) */
                 if (drive->media != ide_disk)
                         break;
                 /* Not supported? Switch to next step now. */
                 if (ata_id_flush_enabled(drive->id) == 0 ||
                     (drive->dev_flags & IDE_DFLAG_WCACHE) == 0) {
                         ide_complete_power_step(drive, rq);
                         return ide_stopped;
                 }
                 if (ata_id_flush_ext_enabled(drive->id))
                         args->tf.command = ATA_CMD_FLUSH_EXT;
                 else
                         args->tf.command = ATA_CMD_FLUSH;
                 goto out_do_tf;
         case IDE_PM_STANDBY:                /* Suspend step 2 (standby) */
                 args->tf.command = ATA_CMD_STANDBYNOW1;
                 goto out_do_tf;
         case IDE_PM_RESTORE_PIO:        /* Resume step 1 (restore PIO) */
                 ide_set_max_pio(drive);
                 /*
                  * skip IDE_PM_IDLE for ATAPI devices
                  */
                 if (drive->media != ide_disk)
                         pm->pm_step = IDE_PM_RESTORE_DMA;
                 else
                         ide_complete_power_step(drive, rq);
                 return ide_stopped;
         case IDE_PM_IDLE:                /* Resume step 2 (idle) */
                 args->tf.command = ATA_CMD_IDLEIMMEDIATE;
                 goto out_do_tf;
         case IDE_PM_RESTORE_DMA:        /* Resume step 3 (restore DMA) */
                 /*
                  * Right now, all we do is call ide_set_dma(drive),
                  * we could be smarter and check for current xfer_speed
                  * in struct drive etc...
                  */
                 if (drive->hwif->dma_ops == NULL)
                         break;
                 /*
                  * TODO: respect IDE_DFLAG_USING_DMA
                  */
                 ide_set_dma(drive);
                 break;
         }
 
         pm->pm_step = IDE_PM_COMPLETED;
         return ide_stopped;
 
 out_do_tf:
         args->tf_flags         = IDE_TFLAG_TF | IDE_TFLAG_DEVICE;
         args->data_phase = TASKFILE_NO_DATA;
         return do_rw_taskfile(drive, args);
 }
 
 /**
  *        ide_end_dequeued_request        -        complete an IDE I/O
  *        @drive: IDE device for the I/O
  *        @uptodate:
  *        @nr_sectors: number of sectors completed
  *
  *        Complete an I/O that is no longer on the request queue. This
  *        typically occurs when we pull the request and issue a REQUEST_SENSE.
  *        We must still finish the old request but we must not tamper with the
  *        queue in the meantime.
  *
  *        NOTE: This path does not handle barrier, but barrier is not supported
  *        on ide-cd anyway.
  */
 
 int ide_end_dequeued_request(ide_drive_t *drive, struct request *rq,
                              int uptodate, int nr_sectors)
 {
         unsigned long flags;
         int ret;
 
         spin_lock_irqsave(&ide_lock, flags);
         BUG_ON(!blk_rq_started(rq));
         ret = __ide_end_request(drive, rq, uptodate, nr_sectors << 9, 0);
         spin_unlock_irqrestore(&ide_lock, flags);
 
         return ret;
 }
 EXPORT_SYMBOL_GPL(ide_end_dequeued_request);
 
 
 /**
  *        ide_complete_pm_request - end the current Power Management request
  *        @drive: target drive
  *        @rq: request
  *
  *        This function cleans up the current PM request and stops the queue
  *        if necessary.
  */
 static void ide_complete_pm_request (ide_drive_t *drive, struct request *rq)
 {
         unsigned long flags;
 
 #ifdef DEBUG_PM
         printk("%s: completing PM request, %s\n", drive->name,
                blk_pm_suspend_request(rq) ? "suspend" : "resume");
 #endif
         spin_lock_irqsave(&ide_lock, flags);
         if (blk_pm_suspend_request(rq)) {
                 blk_stop_queue(drive->queue);
         } else {
                 drive->dev_flags &= ~IDE_DFLAG_BLOCKED;
                 blk_start_queue(drive->queue);
         }
         HWGROUP(drive)->rq = NULL;
         if (__blk_end_request(rq, 0, 0))
                 BUG();
         spin_unlock_irqrestore(&ide_lock, flags);
 }
 
 /**
  *        ide_end_drive_cmd        -        end an explicit drive command
  *        @drive: command 
  *        @stat: status bits
  *        @err: error bits
  *
  *        Clean up after success/failure of an explicit drive command.
  *        These get thrown onto the queue so they are synchronized with
  *        real I/O operations on the drive.
  *
  *        In LBA48 mode we have to read the register set twice to get
  *        all the extra information out.
  */
  
 void ide_end_drive_cmd (ide_drive_t *drive, u8 stat, u8 err)
 {
         unsigned long flags;
         struct request *rq;
 
         spin_lock_irqsave(&ide_lock, flags);
         rq = HWGROUP(drive)->rq;
         spin_unlock_irqrestore(&ide_lock, flags);
 
         if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE) {
                 ide_task_t *task = (ide_task_t *)rq->special;
 
                 if (rq->errors == 0)
                         rq->errors = !OK_STAT(stat, ATA_DRDY, BAD_STAT);
 
                 if (task) {
                         struct ide_taskfile *tf = &task->tf;
 
                         tf->error = err;
                         tf->status = stat;
 
                         drive->hwif->tp_ops->tf_read(drive, task);
 
                         if (task->tf_flags & IDE_TFLAG_DYN)
                                 kfree(task);
                 }
         } else if (blk_pm_request(rq)) {
                 struct request_pm_state *pm = rq->data;
 
                 ide_complete_power_step(drive, rq);
                 if (pm->pm_step == IDE_PM_COMPLETED)
                         ide_complete_pm_request(drive, rq);
                 return;
         }
 
         spin_lock_irqsave(&ide_lock, flags);
         HWGROUP(drive)->rq = NULL;
         rq->errors = err;
         if (unlikely(__blk_end_request(rq, (rq->errors ? -EIO : 0),
                                        blk_rq_bytes(rq))))
                 BUG();
         spin_unlock_irqrestore(&ide_lock, flags);
 }
 
 EXPORT_SYMBOL(ide_end_drive_cmd);
 
 static void ide_kill_rq(ide_drive_t *drive, struct request *rq)
 {
         if (rq->rq_disk) {
                 ide_driver_t *drv;
 
                 drv = *(ide_driver_t **)rq->rq_disk->private_data;
                 drv->end_request(drive, 0, 0);
         } else
                 ide_end_request(drive, 0, 0);
 }
 
 static ide_startstop_t ide_ata_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
 {
         ide_hwif_t *hwif = drive->hwif;
 
         if ((stat & ATA_BUSY) ||
             ((stat & ATA_DF) && (drive->dev_flags & IDE_DFLAG_NOWERR) == 0)) {
                 /* other bits are useless when BUSY */
                 rq->errors |= ERROR_RESET;
         } else if (stat & ATA_ERR) {
                 /* err has different meaning on cdrom and tape */
                 if (err == ATA_ABORTED) {
                         if ((drive->dev_flags & IDE_DFLAG_LBA) &&
                             /* some newer drives don't support ATA_CMD_INIT_DEV_PARAMS */
                             hwif->tp_ops->read_status(hwif) == ATA_CMD_INIT_DEV_PARAMS)
                                 return ide_stopped;
                 } else if ((err & BAD_CRC) == BAD_CRC) {
                         /* UDMA crc error, just retry the operation */
                         drive->crc_count++;
                 } else if (err & (ATA_BBK | ATA_UNC)) {
                         /* retries won't help these */
                         rq->errors = ERROR_MAX;
                 } else if (err & ATA_TRK0NF) {
                         /* help it find track zero */
                         rq->errors |= ERROR_RECAL;
                 }
         }
 
         if ((stat & ATA_DRQ) && rq_data_dir(rq) == READ &&
             (hwif->host_flags & IDE_HFLAG_ERROR_STOPS_FIFO) == 0) {
                 int nsect = drive->mult_count ? drive->mult_count : 1;
 
                 ide_pad_transfer(drive, READ, nsect * SECTOR_SIZE);
         }
 
         if (rq->errors >= ERROR_MAX || blk_noretry_request(rq)) {
                 ide_kill_rq(drive, rq);
                 return ide_stopped;
         }
 
         if (hwif->tp_ops->read_status(hwif) & (ATA_BUSY | ATA_DRQ))
                 rq->errors |= ERROR_RESET;
 
         if ((rq->errors & ERROR_RESET) == ERROR_RESET) {
                 ++rq->errors;
                 return ide_do_reset(drive);
         }
 
         if ((rq->errors & ERROR_RECAL) == ERROR_RECAL)
                 drive->special.b.recalibrate = 1;
 
         ++rq->errors;
 
         return ide_stopped;
 }
 
 static ide_startstop_t ide_atapi_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
 {
         ide_hwif_t *hwif = drive->hwif;
 
         if ((stat & ATA_BUSY) ||
             ((stat & ATA_DF) && (drive->dev_flags & IDE_DFLAG_NOWERR) == 0)) {
                 /* other bits are useless when BUSY */
                 rq->errors |= ERROR_RESET;
         } else {
                 /* add decoding error stuff */
         }
 
         if (hwif->tp_ops->read_status(hwif) & (ATA_BUSY | ATA_DRQ))
                 /* force an abort */
                 hwif->tp_ops->exec_command(hwif, ATA_CMD_IDLEIMMEDIATE);
 
         if (rq->errors >= ERROR_MAX) {
                 ide_kill_rq(drive, rq);
         } else {
                 if ((rq->errors & ERROR_RESET) == ERROR_RESET) {
                         ++rq->errors;
                         return ide_do_reset(drive);
                 }
                 ++rq->errors;
         }
 
         return ide_stopped;
 }
 
 ide_startstop_t
 __ide_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
 {
         if (drive->media == ide_disk)
                 return ide_ata_error(drive, rq, stat, err);
         return ide_atapi_error(drive, rq, stat, err);
 }
 
 EXPORT_SYMBOL_GPL(__ide_error);
 
 /**
  *        ide_error        -        handle an error on the IDE
  *        @drive: drive the error occurred on
  *        @msg: message to report
  *        @stat: status bits
  *
  *        ide_error() takes action based on the error returned by the drive.
  *        For normal I/O that may well include retries. We deal with
  *        both new-style (taskfile) and old style command handling here.
  *        In the case of taskfile command handling there is work left to
  *        do
  */
  
 ide_startstop_t ide_error (ide_drive_t *drive, const char *msg, u8 stat)
 {
         struct request *rq;
         u8 err;
 
         err = ide_dump_status(drive, msg, stat);
 
         if ((rq = HWGROUP(drive)->rq) == NULL)
                 return ide_stopped;
 
         /* retry only "normal" I/O: */
         if (!blk_fs_request(rq)) {
                 rq->errors = 1;
                 ide_end_drive_cmd(drive, stat, err);
                 return ide_stopped;
         }
 
         if (rq->rq_disk) {
                 ide_driver_t *drv;
 
                 drv = *(ide_driver_t **)rq->rq_disk->private_data;
                 return drv->error(drive, rq, stat, err);
         } else
                 return __ide_error(drive, rq, stat, err);
 }
 
 EXPORT_SYMBOL_GPL(ide_error);
 
 static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 {
         tf->nsect   = drive->sect;
         tf->lbal    = drive->sect;
         tf->lbam    = drive->cyl;
         tf->lbah    = drive->cyl >> 8;
         tf->device  = (drive->head - 1) | drive->select;
         tf->command = ATA_CMD_INIT_DEV_PARAMS;
 }
 
 static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 {
         tf->nsect   = drive->sect;
         tf->command = ATA_CMD_RESTORE;
 }
 
 static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 {
         tf->nsect   = drive->mult_req;
         tf->command = ATA_CMD_SET_MULTI;
 }
 
 static ide_startstop_t ide_disk_special(ide_drive_t *drive)
 {
         special_t *s = &drive->special;
         ide_task_t args;
 
         memset(&args, 0, sizeof(ide_task_t));
         args.data_phase = TASKFILE_NO_DATA;
 
         if (s->b.set_geometry) {
                 s->b.set_geometry = 0;
                 ide_tf_set_specify_cmd(drive, &args.tf);
         } else if (s->b.recalibrate) {
                 s->b.recalibrate = 0;
                 ide_tf_set_restore_cmd(drive, &args.tf);
         } else if (s->b.set_multmode) {
                 s->b.set_multmode = 0;
                 ide_tf_set_setmult_cmd(drive, &args.tf);
         } else if (s->all) {
                 int special = s->all;
                 s->all = 0;
                 printk(KERN_ERR "%s: bad special flag: 0x%02x\n", drive->name, special);
                 return ide_stopped;
         }
 
         args.tf_flags = IDE_TFLAG_TF | IDE_TFLAG_DEVICE |
                         IDE_TFLAG_CUSTOM_HANDLER;
 
         do_rw_taskfile(drive, &args);
 
         return ide_started;
 }
 
 /**
  *        do_special                -        issue some special commands
  *        @drive: drive the command is for
  *
  *        do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS,
  *        ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive.
  *
  *        It used to do much more, but has been scaled back.
  */
 
 static ide_startstop_t do_special (ide_drive_t *drive)
 {
         special_t *s = &drive->special;
 
 #ifdef DEBUG
         printk("%s: do_special: 0x%02x\n", drive->name, s->all);
 #endif
         if (drive->media == ide_disk)
                 return ide_disk_special(drive);
 
         s->all = 0;
         drive->mult_req = 0;
         return ide_stopped;
 }
 
 void ide_map_sg(ide_drive_t *drive, struct request *rq)
 {
         ide_hwif_t *hwif = drive->hwif;
         struct scatterlist *sg = hwif->sg_table;
 
         if (hwif->sg_mapped)        /* needed by ide-scsi */
                 return;
 
         if (rq->cmd_type != REQ_TYPE_ATA_TASKFILE) {
                 hwif->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
         } else {
                 sg_init_one(sg, rq->buffer, rq->nr_sectors * SECTOR_SIZE);
                 hwif->sg_nents = 1;
         }
 }
 
 EXPORT_SYMBOL_GPL(ide_map_sg);
 
 void ide_init_sg_cmd(ide_drive_t *drive, struct request *rq)
 {
         ide_hwif_t *hwif = drive->hwif;
 
         hwif->nsect = hwif->nleft = rq->nr_sectors;
         hwif->cursg_ofs = 0;
         hwif->cursg = NULL;
 }
 
 EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
 
 /**
  *        execute_drive_command        -        issue special drive command
  *        @drive: the drive to issue the command on
  *        @rq: the request structure holding the command
  *
  *        execute_drive_cmd() issues a special drive command,  usually 
  *        initiated by ioctl() from the external hdparm program. The
  *        command can be a drive command, drive task or taskfile 
  *        operation. Weirdly you can call it with NULL to wait for
  *        all commands to finish. Don't do this as that is due to change
  */
 
 static ide_startstop_t execute_drive_cmd (ide_drive_t *drive,
                 struct request *rq)
 {
         ide_hwif_t *hwif = HWIF(drive);
         ide_task_t *task = rq->special;
 
         if (task) {
                 hwif->data_phase = task->data_phase;
 
                 switch (hwif->data_phase) {
                 case TASKFILE_MULTI_OUT:
                 case TASKFILE_OUT:
                 case TASKFILE_MULTI_IN:
                 case TASKFILE_IN:
                         ide_init_sg_cmd(drive, rq);
                         ide_map_sg(drive, rq);
                 default:
                         break;
                 }
 
                 return do_rw_taskfile(drive, task);
         }
 
          /*
           * NULL is actually a valid way of waiting for
           * all current requests to be flushed from the queue.
           */
 #ifdef DEBUG
          printk("%s: DRIVE_CMD (null)\n", drive->name);
 #endif
         ide_end_drive_cmd(drive, hwif->tp_ops->read_status(hwif),
                           ide_read_error(drive));
 
          return ide_stopped;
 }
 
 int ide_devset_execute(ide_drive_t *drive, const struct ide_devset *setting,
                        int arg)
 {
         struct request_queue *q = drive->queue;
         struct request *rq;
         int ret = 0;
 
         if (!(setting->flags & DS_SYNC))
                 return setting->set(drive, arg);
 
         rq = blk_get_request(q, READ, __GFP_WAIT);
         rq->cmd_type = REQ_TYPE_SPECIAL;
         rq->cmd_len = 5;
         rq->cmd[0] = REQ_DEVSET_EXEC;
         *(int *)&rq->cmd[1] = arg;
         rq->special = setting->set;
 
         if (blk_execute_rq(q, NULL, rq, 0))
                 ret = rq->errors;
         blk_put_request(rq);
 
         return ret;
 }
 EXPORT_SYMBOL_GPL(ide_devset_execute);
 
 static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
 {
         u8 cmd = rq->cmd[0];
 
         if (cmd == REQ_PARK_HEADS || cmd == REQ_UNPARK_HEADS) {
                 ide_task_t task;
                 struct ide_taskfile *tf = &task.tf;
 
                 memset(&task, 0, sizeof(task));
                 if (cmd == REQ_PARK_HEADS) {
                         drive->sleep = *(unsigned long *)rq->special;
                         drive->dev_flags |= IDE_DFLAG_SLEEPING;
                         tf->command = ATA_CMD_IDLEIMMEDIATE;
                         tf->feature = 0x44;
                         tf->lbal = 0x4c;
                         tf->lbam = 0x4e;
                         tf->lbah = 0x55;
                         task.tf_flags |= IDE_TFLAG_CUSTOM_HANDLER;
                 } else                /* cmd == REQ_UNPARK_HEADS */
                         tf->command = ATA_CMD_CHK_POWER;
 
                 task.tf_flags |= IDE_TFLAG_TF | IDE_TFLAG_DEVICE;
                 task.rq = rq;
                 drive->hwif->data_phase = task.data_phase = TASKFILE_NO_DATA;
                 return do_rw_taskfile(drive, &task);
         }
 
         switch (cmd) {
         case REQ_DEVSET_EXEC:
         {
                 int err, (*setfunc)(ide_drive_t *, int) = rq->special;
 
                 err = setfunc(drive, *(int *)&rq->cmd[1]);
                 if (err)
                         rq->errors = err;
                 else
                         err = 1;
                 ide_end_request(drive, err, 0);
                 return ide_stopped;
         }
         case REQ_DRIVE_RESET:
                 return ide_do_reset(drive);
         default:
                 blk_dump_rq_flags(rq, "ide_special_rq - bad request");
                 ide_end_request(drive, 0, 0);
                 return ide_stopped;
         }
 }
 
 static void ide_check_pm_state(ide_drive_t *drive, struct request *rq)
 {
         struct request_pm_state *pm = rq->data;
 
         if (blk_pm_suspend_request(rq) &&
             pm->pm_step == IDE_PM_START_SUSPEND)
                 /* Mark drive blocked when starting the suspend sequence. */
                 drive->dev_flags |= IDE_DFLAG_BLOCKED;
         else if (blk_pm_resume_request(rq) &&
                  pm->pm_step == IDE_PM_START_RESUME) {
                 /* 
                  * The first thing we do on wakeup is to wait for BSY bit to
                  * go away (with a looong timeout) as a drive on this hwif may
                  * just be POSTing itself.
                  * We do that before even selecting as the "other" device on
                  * the bus may be broken enough to walk on our toes at this
                  * point.
                  */
                 ide_hwif_t *hwif = drive->hwif;
                 int rc;
 #ifdef DEBUG_PM
                 printk("%s: Wakeup request inited, waiting for !BSY...\n", drive->name);
 #endif
                 rc = ide_wait_not_busy(hwif, 35000);
                 if (rc)
                         printk(KERN_WARNING "%s: bus not ready on wakeup\n", drive->name);
                 SELECT_DRIVE(drive);
                 hwif->tp_ops->set_irq(hwif, 1);
                 rc = ide_wait_not_busy(hwif, 100000);
                 if (rc)
                         printk(KERN_WARNING "%s: drive not ready on wakeup\n", drive->name);
         }
 }
 
 /**
  *        start_request        -        start of I/O and command issuing for IDE
  *
  *        start_request() initiates handling of a new I/O request. It
  *        accepts commands and I/O (read/write) requests.
  *
  *        FIXME: this function needs a rename
  */
  
 static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
 {
         ide_startstop_t startstop;
 
         BUG_ON(!blk_rq_started(rq));
 
 #ifdef DEBUG
         printk("%s: start_request: current=0x%08lx\n",
                 HWIF(drive)->name, (unsigned long) rq);
 #endif
 
         /* bail early if we've exceeded max_failures */
         if (drive->max_failures && (drive->failures > drive->max_failures)) {
                 rq->cmd_flags |= REQ_FAILED;
                 goto kill_rq;
         }
 
         if (blk_pm_request(rq))
                 ide_check_pm_state(drive, rq);
 
         SELECT_DRIVE(drive);
         if (ide_wait_stat(&startstop, drive, drive->ready_stat,
                           ATA_BUSY | ATA_DRQ, WAIT_READY)) {
                 printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
                 return startstop;
         }
         if (!drive->special.all) {
                 ide_driver_t *drv;
 
                 /*
                  * We reset the drive so we need to issue a SETFEATURES.
                  * Do it _after_ do_special() restored device parameters.
                  */
                 if (drive->current_speed == 0xff)
                         ide_config_drive_speed(drive, drive->desired_speed);
 
                 if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
                         return execute_drive_cmd(drive, rq);
                 else if (blk_pm_request(rq)) {
                         struct request_pm_state *pm = rq->data;
 #ifdef DEBUG_PM
                         printk("%s: start_power_step(step: %d)\n",
                                 drive->name, pm->pm_step);
 #endif
                         startstop = ide_start_power_step(drive, rq);
                         if (startstop == ide_stopped &&
                             pm->pm_step == IDE_PM_COMPLETED)
                                 ide_complete_pm_request(drive, rq);
                         return startstop;
                 } else if (!rq->rq_disk && blk_special_request(rq))
                         /*
                          * TODO: Once all ULDs have been modified to
                          * check for specific op codes rather than
                          * blindly accepting any special request, the
                          * check for ->rq_disk above may be replaced
                          * by a more suitable mechanism or even
                          * dropped entirely.
                          */
                         return ide_special_rq(drive, rq);
 
                 drv = *(ide_driver_t **)rq->rq_disk->private_data;
 
                 return drv->do_request(drive, rq, rq->sector);
         }
         return do_special(drive);
 kill_rq:
         ide_kill_rq(drive, rq);
         return ide_stopped;
 }
 
 /**
  *        ide_stall_queue                -        pause an IDE device
  *        @drive: drive to stall
  *        @timeout: time to stall for (jiffies)
  *
  *        ide_stall_queue() can be used by a drive to give excess bandwidth back
  *        to the hwgroup by sleeping for timeout jiffies.
  */
  
 void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
 {
         if (timeout > WAIT_WORSTCASE)
                 timeout = WAIT_WORSTCASE;
         drive->sleep = timeout + jiffies;
         drive->dev_flags |= IDE_DFLAG_SLEEPING;
 }
 
 EXPORT_SYMBOL(ide_stall_queue);
 
 #define WAKEUP(drive)        ((drive)->service_start + 2 * (drive)->service_time)
 
 /**
  *        choose_drive                -        select a drive to service
  *        @hwgroup: hardware group to select on
  *
  *        choose_drive() selects the next drive which will be serviced.
  *        This is necessary because the IDE layer can't issue commands
  *        to both drives on the same cable, unlike SCSI.
  */
  
 static inline ide_drive_t *choose_drive (ide_hwgroup_t *hwgroup)
 {
         ide_drive_t *drive, *best;
 
 repeat:        
         best = NULL;
         drive = hwgroup->drive;
 
         /*
          * drive is doing pre-flush, ordered write, post-flush sequence. even
          * though that is 3 requests, it must be seen as a single transaction.
          * we must not preempt this drive until that is complete
          */
         if (blk_queue_flushing(drive->queue)) {
                 /*
                  * small race where queue could get replugged during
                  * the 3-request flush cycle, just yank the plug since
                  * we want it to finish asap
                  */
                 blk_remove_plug(drive->queue);
                 return drive;
         }
 
         do {
                 u8 dev_s = !!(drive->dev_flags & IDE_DFLAG_SLEEPING);
                 u8 best_s = (best && !!(best->dev_flags & IDE_DFLAG_SLEEPING));
 
                 if ((dev_s == 0 || time_after_eq(jiffies, drive->sleep)) &&
                     !elv_queue_empty(drive->queue)) {
                         if (best == NULL ||
                             (dev_s && (best_s == 0 || time_before(drive->sleep, best->sleep))) ||
                             (best_s == 0 && time_before(WAKEUP(drive), WAKEUP(best)))) {
                                 if (!blk_queue_plugged(drive->queue))
                                         best = drive;
                         }
                 }
         } while ((drive = drive->next) != hwgroup->drive);
 
         if (best && (best->dev_flags & IDE_DFLAG_NICE1) &&
             (best->dev_flags & IDE_DFLAG_SLEEPING) == 0 &&
             best != hwgroup->drive && best->service_time > WAIT_MIN_SLEEP) {
                 long t = (signed long)(WAKEUP(best) - jiffies);
                 if (t >= WAIT_MIN_SLEEP) {
                 /*
                  * We *may* have some time to spare, but first let's see if
                  * someone can potentially benefit from our nice mood today..
                  */
                         drive = best->next;
                         do {
                                 if ((drive->dev_flags & IDE_DFLAG_SLEEPING) == 0
                                  && time_before(jiffies - best->service_time, WAKEUP(drive))
                                  && time_before(WAKEUP(drive), jiffies + t))
                                 {
                                         ide_stall_queue(best, min_t(long, t, 10 * WAIT_MIN_SLEEP));
                                         goto repeat;
                                 }
                         } while ((drive = drive->next) != best);
                 }
         }
         return best;
 }
 
 /*
  * Issue a new request to a drive from hwgroup
  * Caller must have already done spin_lock_irqsave(&ide_lock, ..);
  *
  * A hwgroup is a serialized group of IDE interfaces.  Usually there is
  * exactly one hwif (interface) per hwgroup, but buggy controllers (eg. CMD640)
  * may have both interfaces in a single hwgroup to "serialize" access.
  * Or possibly multiple ISA interfaces can share a common IRQ by being grouped
  * together into one hwgroup for serialized access.
  *
  * Note also that several hwgroups can end up sharing a single IRQ,
  * possibly along with many other devices.  This is especially common in
  * PCI-based systems with off-board IDE controller cards.
  *
  * The IDE driver uses the single global ide_lock spinlock to protect
  * access to the request queues, and to protect the hwgroup->busy flag.
  *
  * The first thread into the driver for a particular hwgroup sets the
  * hwgroup->busy flag to indicate that this hwgroup is now active,
  * and then initiates processing of the top request from the request queue.
  *
  * Other threads attempting entry notice the busy setting, and will simply
  * queue their new requests and exit immediately.  Note that hwgroup->busy
  * remains set even when the driver is merely awaiting the next interrupt.
  * Thus, the meaning is "this hwgroup is busy processing a request".
  *
  * When processing of a request completes, the completing thread or IRQ-handler
  * will start the next request from the queue.  If no more work remains,
  * the driver will clear the hwgroup->busy flag and exit.
  *
  * The ide_lock (spinlock) is used to protect all access to the
  * hwgroup->busy flag, but is otherwise not needed for most processing in
  * the driver.  This makes the driver much more friendlier to shared IRQs
  * than previous designs, while remaining 100% (?) SMP safe and capable.
  */
 static void ide_do_request (ide_hwgroup_t *hwgroup, int masked_irq)
 {
         ide_drive_t        *drive;
         ide_hwif_t        *hwif;
         struct request        *rq;
         ide_startstop_t        startstop;
         int             loops = 0;
 
         /* caller must own ide_lock */
         BUG_ON(!irqs_disabled());
 
         while (!hwgroup->busy) {
                 hwgroup->busy = 1;
                 /* for atari only */
                 ide_get_lock(ide_intr, hwgroup);
                 drive = choose_drive(hwgroup);
                 if (drive == NULL) {
                         int sleeping = 0;
                         unsigned long sleep = 0; /* shut up, gcc */
                         hwgroup->rq = NULL;
                         drive = hwgroup->drive;
                         do {
                                 if ((drive->dev_flags & IDE_DFLAG_SLEEPING) &&
                                     (sleeping == 0 ||
                                      time_before(drive->sleep, sleep))) {
                                         sleeping = 1;
                                         sleep = drive->sleep;
                                 }
                         } while ((drive = drive->next) != hwgroup->drive);
                         if (sleeping) {
                 /*
                  * Take a short snooze, and then wake up this hwgroup again.
                  * This gives other hwgroups on the same a chance to
                  * play fairly with us, just in case there are big differences
                  * in relative throughputs.. don't want to hog the cpu too much.
                  */
                                 if (time_before(sleep, jiffies + WAIT_MIN_SLEEP))
                                        sleep = jiffies + WAIT_MIN_SLEEP;
#if 1
                                if (timer_pending(&hwgroup->timer))
                                        printk(KERN_CRIT "ide_set_handler: timer already active\n");
#endif
                                /* so that ide_timer_expiry knows what to do */
                                hwgroup->sleeping = 1;
                                hwgroup->req_gen_timer = hwgroup->req_gen;
                                mod_timer(&hwgroup->timer, sleep);
                                /* we purposely leave hwgroup->busy==1
                                 * while sleeping */
                        } else {
                                /* Ugly, but how can we sleep for the lock
                                 * otherwise? perhaps from tq_disk?
                                 */

                                /* for atari only */
                                ide_release_lock();
                                hwgroup->busy = 0;
                        }

                        /* no more work for this hwgroup (for now) */
                        return;
                }
        again:
                hwif = HWIF(drive);
                if (hwgroup->hwif->sharing_irq && hwif != hwgroup->hwif) {
                        /*
                         * set nIEN for previous hwif, drives in the
                         * quirk_list may not like intr setups/cleanups
                         */
                        if (drive->quirk_list != 1)
                                hwif->tp_ops->set_irq(hwif, 0);
                }
                hwgroup->hwif = hwif;
                hwgroup->drive = drive;
                drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
                drive->service_start = jiffies;

                if (blk_queue_plugged(drive->queue)) {
                        printk(KERN_ERR "ide: huh? queue was plugged!\n");
                        break;
                }

                /*
                 * we know that the queue isn't empty, but this can happen
                 * if the q->prep_rq_fn() decides to kill a request
                 */
                rq = elv_next_request(drive->queue);
                if (!rq) {
                        hwgroup->busy = 0;
                        break;
                }

                /*
                 * Sanity: don't accept a request that isn't a PM request
                 * if we are currently power managed. This is very important as
                 * blk_stop_queue() doesn't prevent the elv_next_request()
                 * above to return us whatever is in the queue. Since we call
                 * ide_do_request() ourselves, we end up taking requests while
                 * the queue is blocked...
                 * 
                 * We let requests forced at head of queue with ide-preempt
                 * though. I hope that doesn't happen too much, hopefully not
                 * unless the subdriver triggers such a thing in its own PM
                 * state machine.
                 *
                 * We count how many times we loop here to make sure we service
                 * all drives in the hwgroup without looping for ever
                 */
                if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
                    blk_pm_request(rq) == 0 &&
                    (rq->cmd_flags & REQ_PREEMPT) == 0) {
                        drive = drive->next ? drive->next : hwgroup->drive;
                        if (loops++ < 4 && !blk_queue_plugged(drive->queue))
                                goto again;
                        /* We clear busy, there should be no pending ATA command at this point. */
                        hwgroup->busy = 0;
                        break;
                }

                hwgroup->rq = rq;

                /*
                 * Some systems have trouble with IDE IRQs arriving while
                 * the driver is still setting things up.  So, here we disable
                 * the IRQ used by this interface while the request is being started.
                 * This may look bad at first, but pretty much the same thing
                 * happens anyway when any interrupt comes in, IDE or otherwise
                 *  -- the kernel masks the IRQ while it is being handled.
                 */
                if (masked_irq != IDE_NO_IRQ && hwif->irq != masked_irq)
                        disable_irq_nosync(hwif->irq);
                spin_unlock(&ide_lock);
                local_irq_enable_in_hardirq();
                        /* allow other IRQs while we start this request */
                startstop = start_request(drive, rq);
                spin_lock_irq(&ide_lock);
                if (masked_irq != IDE_NO_IRQ && hwif->irq != masked_irq)
                        enable_irq(hwif->irq);
                if (startstop == ide_stopped)
                        hwgroup->busy = 0;
        }
}

/*
 * Passes the stuff to ide_do_request
 */
void do_ide_request(struct request_queue *q)
{
        ide_drive_t *drive = q->queuedata;

        ide_do_request(HWGROUP(drive), IDE_NO_IRQ);
}

/*
 * un-busy the hwgroup etc, and clear any pending DMA status. we want to
 * retry the current request in pio mode instead of risking tossing it
 * all away
 */
static ide_startstop_t ide_dma_timeout_retry(ide_drive_t *drive, int error)
{
        ide_hwif_t *hwif = HWIF(drive);
        struct request *rq;
        ide_startstop_t ret = ide_stopped;

        /*
         * end current dma transaction
         */

        if (error < 0) {
                printk(KERN_WARNING "%s: DMA timeout error\n", drive->name);
                (void)hwif->dma_ops->dma_end(drive);
                ret = ide_error(drive, "dma timeout error",
                                hwif->tp_ops->read_status(hwif));
        } else {
                printk(KERN_WARNING "%s: DMA timeout retry\n", drive->name);
                hwif->dma_ops->dma_timeout(drive);
        }

        /*
         * disable dma for now, but remember that we did so because of
         * a timeout -- we'll reenable after we finish this next request
         * (or rather the first chunk of it) in pio.
         */
        drive->dev_flags |= IDE_DFLAG_DMA_PIO_RETRY;
        drive->retry_pio++;
        ide_dma_off_quietly(drive);

        /*
         * un-busy drive etc (hwgroup->busy is cleared on return) and
         * make sure request is sane
         */
        rq = HWGROUP(drive)->rq;

        if (!rq)
                goto out;

        HWGROUP(drive)->rq = NULL;

        rq->errors = 0;

        if (!rq->bio)
                goto out;

        rq->sector = rq->bio->bi_sector;
        rq->current_nr_sectors = bio_iovec(rq->bio)->bv_len >> 9;
        rq->hard_cur_sectors = rq->current_nr_sectors;
        rq->buffer = bio_data(rq->bio);
out:
        return ret;
}

/**
 *        ide_timer_expiry        -        handle lack of an IDE interrupt
 *        @data: timer callback magic (hwgroup)
 *
 *        An IDE command has timed out before the expected drive return
 *        occurred. At this point we attempt to clean up the current
 *        mess. If the current handler includes an expiry handler then
 *        we invoke the expiry handler, and providing it is happy the
 *        work is done. If that fails we apply generic recovery rules
 *        invoking the handler and checking the drive DMA status. We
 *        have an excessively incestuous relationship with the DMA
 *        logic that wants cleaning up.
 */
 
void ide_timer_expiry (unsigned long data)
{
        ide_hwgroup_t        *hwgroup = (ide_hwgroup_t *) data;
        ide_handler_t        *handler;
        ide_expiry_t        *expiry;
        unsigned long        flags;
        unsigned long        wait = -1;

        spin_lock_irqsave(&ide_lock, flags);

        if (((handler = hwgroup->handler) == NULL) ||
            (hwgroup->req_gen != hwgroup->req_gen_timer)) {
                /*
                 * Either a marginal timeout occurred
                 * (got the interrupt just as timer expired),
                 * or we were "sleeping" to give other devices a chance.
                 * Either way, we don't really want to complain about anything.
                 */
                if (hwgroup->sleeping) {
                        hwgroup->sleeping = 0;
                        hwgroup->busy = 0;
                }
        } else {
                ide_drive_t *drive = hwgroup->drive;
                if (!drive) {
                        printk(KERN_ERR "ide_timer_expiry: hwgroup->drive was NULL\n");
                        hwgroup->handler = NULL;
                } else {
                        ide_hwif_t *hwif;
                        ide_startstop_t startstop = ide_stopped;
                        if (!hwgroup->busy) {
                                hwgroup->busy = 1;        /* paranoia */
                                printk(KERN_ERR "%s: ide_timer_expiry: hwgroup->busy was 0 ??\n", drive->name);
                        }
                        if ((expiry = hwgroup->expiry) != NULL) {
                                /* continue */
                                if ((wait = expiry(drive)) > 0) {
                                        /* reset timer */
                                        hwgroup->timer.expires  = jiffies + wait;
                                        hwgroup->req_gen_timer = hwgroup->req_gen;
                                        add_timer(&hwgroup->timer);
                                        spin_unlock_irqrestore(&ide_lock, flags);
                                        return;
                                }
                        }
                        hwgroup->handler = NULL;
                        /*
                         * We need to simulate a real interrupt when invoking
                         * the handler() function, which means we need to
                         * globally mask the specific IRQ:
                         */
                        spin_unlock(&ide_lock);
                        hwif  = HWIF(drive);
                        /* disable_irq_nosync ?? */
                        disable_irq(hwif->irq);
                        /* local CPU only,
                         * as if we were handling an interrupt */
                        local_irq_disable();
                        if (hwgroup->polling) {
                                startstop = handler(drive);
                        } else if (drive_is_ready(drive)) {
                                if (drive->waiting_for_dma)
                                        hwif->dma_ops->dma_lost_irq(drive);
                                (void)ide_ack_intr(hwif);
                                printk(KERN_WARNING "%s: lost interrupt\n", drive->name);
                                startstop = handler(drive);
                        } else {
                                if (drive->waiting_for_dma) {
                                        startstop = ide_dma_timeout_retry(drive, wait);
                                } else
                                        startstop =
                                        ide_error(drive, "irq timeout",
                                                  hwif->tp_ops->read_status(hwif));
                        }
                        drive->service_time = jiffies - drive->service_start;
                        spin_lock_irq(&ide_lock);
                        enable_irq(hwif->irq);
                        if (startstop == ide_stopped)
                                hwgroup->busy = 0;
                }
        }
        ide_do_request(hwgroup, IDE_NO_IRQ);
        spin_unlock_irqrestore(&ide_lock, flags);
}

/**
 *        unexpected_intr                -        handle an unexpected IDE interrupt
 *        @irq: interrupt line
 *        @hwgroup: hwgroup being processed
 *
 *        There's nothing really useful we can do with an unexpected interrupt,
 *        other than reading the status register (to clear it), and logging it.
 *        There should be no way that an irq can happen before we're ready for it,
 *        so we needn't worry much about losing an "important" interrupt here.
 *
 *        On laptops (and "green" PCs), an unexpected interrupt occurs whenever
 *        the drive enters "idle", "standby", or "sleep" mode, so if the status
 *        looks "good", we just ignore the interrupt completely.
 *
 *        This routine assumes __cli() is in effect when called.
 *
 *        If an unexpected interrupt happens on irq15 while we are handling irq14
 *        and if the two interfaces are "serialized" (CMD640), then it looks like
 *        we could screw up by interfering with a new request being set up for 
 *        irq15.
 *
 *        In reality, this is a non-issue.  The new command is not sent unless 
 *        the drive is ready to accept one, in which case we know the drive is
 *        not trying to interrupt us.  And ide_set_handler() is always invoked
 *        before completing the issuance of any new drive command, so we will not
 *        be accidentally invoked as a result of any valid command completion
 *        interrupt.
 *
 *        Note that we must walk the entire hwgroup here. We know which hwif
 *        is doing the current command, but we don't know which hwif burped
 *        mysteriously.
 */
 
static void unexpected_intr (int irq, ide_hwgroup_t *hwgroup)
{
        u8 stat;
        ide_hwif_t *hwif = hwgroup->hwif;

        /*
         * handle the unexpected interrupt
         */
        do {
                if (hwif->irq == irq) {
                        stat = hwif->tp_ops->read_status(hwif);

                        if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
                                /* Try to not flood the console with msgs */
                                static unsigned long last_msgtime, count;
                                ++count;
                                if (time_after(jiffies, last_msgtime + HZ)) {
                                        last_msgtime = jiffies;
                                        printk(KERN_ERR "%s%s: unexpected interrupt, "
                                                "status=0x%02x, count=%ld\n",
                                                hwif->name,
                                                (hwif->next==hwgroup->hwif) ? "" : "(?)", stat, count);
                                }
                        }
                }
        } while ((hwif = hwif->next) != hwgroup->hwif);
}

/**
 *        ide_intr        -        default IDE interrupt handler
 *        @irq: interrupt number
 *        @dev_id: hwif group
 *        @regs: unused weirdness from the kernel irq layer
 *
 *        This is the default IRQ handler for the IDE layer. You should
 *        not need to override it. If you do be aware it is subtle in
 *        places
 *
 *        hwgroup->hwif is the interface in the group currently performing
 *        a command. hwgroup->drive is the drive and hwgroup->handler is
 *        the IRQ handler to call. As we issue a command the handlers
 *        step through multiple states, reassigning the handler to the
 *        next step in the process. Unlike a smart SCSI controller IDE
 *        expects the main processor to sequence the various transfer
 *        stages. We also manage a poll timer to catch up with most
 *        timeout situations. There are still a few where the handlers
 *        don't ever decide to give up.
 *
 *        The handler eventually returns ide_stopped to indicate the
 *        request completed. At this point we issue the next request
 *        on the hwgroup and the process begins again.
 */
 
irqreturn_t ide_intr (int irq, void *dev_id)
{
        unsigned long flags;
        ide_hwgroup_t *hwgroup = (ide_hwgroup_t *)dev_id;
        ide_hwif_t *hwif;
        ide_drive_t *drive;
        ide_handler_t *handler;
        ide_startstop_t startstop;

        spin_lock_irqsave(&ide_lock, flags);
        hwif = hwgroup->hwif;

        if (!ide_ack_intr(hwif)) {
                spin_unlock_irqrestore(&ide_lock, flags);
                return IRQ_NONE;
        }

        if ((handler = hwgroup->handler) == NULL || hwgroup->polling) {
                /*
                 * Not expecting an interrupt from this drive.
                 * That means this could be:
                 *        (1) an interrupt from another PCI device
                 *        sharing the same PCI INT# as us.
                 * or        (2) a drive just entered sleep or standby mode,
                 *        and is interrupting to let us know.
                 * or        (3) a spurious interrupt of unknown origin.
                 *
                 * For PCI, we cannot tell the difference,
                 * so in that case we just ignore it and hope it goes away.
                 *
                 * FIXME: unexpected_intr should be hwif-> then we can
                 * remove all the ifdef PCI crap
                 */
#ifdef CONFIG_BLK_DEV_IDEPCI
                if (hwif->chipset != ide_pci)
#endif        /* CONFIG_BLK_DEV_IDEPCI */
                {
                        /*
                         * Probably not a shared PCI interrupt,
                         * so we can safely try to do something about it:
                         */
                        unexpected_intr(irq, hwgroup);
#ifdef CONFIG_BLK_DEV_IDEPCI
                } else {
                        /*
                         * Whack the status register, just in case
                         * we have a leftover pending IRQ.
                         */
                        (void)hwif->tp_ops->read_status(hwif);
#endif /* CONFIG_BLK_DEV_IDEPCI */
                }
                spin_unlock_irqrestore(&ide_lock, flags);
                return IRQ_NONE;
        }
        drive = hwgroup->drive;
        if (!drive) {
                /*
                 * This should NEVER happen, and there isn't much
                 * we could do about it here.
                 *
                 * [Note - this can occur if the drive is hot unplugged]
                 */
                spin_unlock_irqrestore(&ide_lock, flags);
                return IRQ_HANDLED;
        }
        if (!drive_is_ready(drive)) {
                /*
                 * This happens regularly when we share a PCI IRQ with
                 * another device.  Unfortunately, it can also happen
                 * with some buggy drives that trigger the IRQ before
                 * their status register is up to date.  Hopefully we have
                 * enough advance overhead that the latter isn't a problem.
                 */
                spin_unlock_irqrestore(&ide_lock, flags);
                return IRQ_NONE;
        }
        if (!hwgroup->busy) {
                hwgroup->busy = 1;        /* paranoia */
                printk(KERN_ERR "%s: ide_intr: hwgroup->busy was 0 ??\n", drive->name);
        }
        hwgroup->handler = NULL;
        hwgroup->req_gen++;
        del_timer(&hwgroup->timer);
        spin_unlock(&ide_lock);

        if (hwif->port_ops && hwif->port_ops->clear_irq)
                hwif->port_ops->clear_irq(drive);

        if (drive->dev_flags & IDE_DFLAG_UNMASK)
                local_irq_enable_in_hardirq();

        /* service this interrupt, may set handler for next interrupt */
        startstop = handler(drive);

        spin_lock_irq(&ide_lock);
        /*
         * Note that handler() may have set things up for another
         * interrupt to occur soon, but it cannot happen until
         * we exit from this routine, because it will be the
         * same irq as is currently being serviced here, and Linux
         * won't allow another of the same (on any CPU) until we return.
         */
        drive->service_time = jiffies - drive->service_start;
        if (startstop == ide_stopped) {
                if (hwgroup->handler == NULL) {        /* paranoia */
                        hwgroup->busy = 0;
                        ide_do_request(hwgroup, hwif->irq);
                } else {
                        printk(KERN_ERR "%s: ide_intr: huh? expected NULL handler "
                                "on exit\n", drive->name);
                }
        }
        spin_unlock_irqrestore(&ide_lock, flags);
        return IRQ_HANDLED;
}

/**
 *        ide_do_drive_cmd        -        issue IDE special command
 *        @drive: device to issue command
 *        @rq: request to issue
 *
 *        This function issues a special IDE device request
 *        onto the request queue.
 *
 *        the rq is queued at the head of the request queue, displacing
 *        the currently-being-processed request and this function
 *        returns immediately without waiting for the new rq to be
 *        completed.  This is VERY DANGEROUS, and is intended for
 *        careful use by the ATAPI tape/cdrom driver code.
 */

void ide_do_drive_cmd(ide_drive_t *drive, struct request *rq)
{
        unsigned long flags;
        ide_hwgroup_t *hwgroup = HWGROUP(drive);

        spin_lock_irqsave(&ide_lock, flags);
        hwgroup->rq = NULL;
        __elv_add_request(drive->queue, rq, ELEVATOR_INSERT_FRONT, 0);
        blk_start_queueing(drive->queue);
        spin_unlock_irqrestore(&ide_lock, flags);
}

EXPORT_SYMBOL(ide_do_drive_cmd);

void ide_pktcmd_tf_load(ide_drive_t *drive, u32 tf_flags, u16 bcount, u8 dma)
{
        ide_hwif_t *hwif = drive->hwif;
        ide_task_t task;

        memset(&task, 0, sizeof(task));
        task.tf_flags = IDE_TFLAG_OUT_LBAH | IDE_TFLAG_OUT_LBAM |
                        IDE_TFLAG_OUT_FEATURE | tf_flags;
        task.tf.feature = dma;                /* Use PIO/DMA */
        task.tf.lbam    = bcount & 0xff;
        task.tf.lbah    = (bcount >> 8) & 0xff;

        ide_tf_dump(drive->name, &task.tf);
        hwif->tp_ops->set_irq(hwif, 1);
        SELECT_MASK(drive, 0);
        hwif->tp_ops->tf_load(drive, &task);
}

EXPORT_SYMBOL_GPL(ide_pktcmd_tf_load);

void ide_pad_transfer(ide_drive_t *drive, int write, int len)
{
        ide_hwif_t *hwif = drive->hwif;
        u8 buf[4] = { 0 };

        while (len > 0) {
                if (write)
                        hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
                else
                        hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
                len -= 4;
        }
}
EXPORT_SYMBOL_GPL(ide_pad_transfer);