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viotape.c

/* -*- linux-c -*-
 *  drivers/char/viotape.c
 *
 *  iSeries Virtual Tape
 *
 *  Authors: Dave Boutcher <boutcher@us.ibm.com>
 *           Ryan Arnold <ryanarn@us.ibm.com>
 *           Colin Devilbiss <devilbis@us.ibm.com>
 *           Stephen Rothwell <sfr@au1.ibm.com>
 *
 * (C) Copyright 2000-2004 IBM Corporation
 *
 * 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 of the
 * License, or (at your option) anyu later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * This routine provides access to tape drives owned and managed by an OS/400
 * partition running on the same box as this Linux partition.
 *
 * All tape operations are performed by sending messages back and forth to
 * the OS/400 partition.  The format of the messages is defined in
 * iseries/vio.h
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/spinlock.h>
#include <linux/mtio.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/major.h>
#include <linux/completion.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>

#include <asm/uaccess.h>
#include <asm/ioctls.h>
#include <asm/firmware.h>
#include <asm/vio.h>
#include <asm/iseries/vio.h>
#include <asm/iseries/hv_lp_event.h>
#include <asm/iseries/hv_call_event.h>
#include <asm/iseries/hv_lp_config.h>

#define VIOTAPE_VERSION       "1.2"
#define VIOTAPE_MAXREQ        1

#define VIOTAPE_KERN_WARN     KERN_WARNING "viotape: "
#define VIOTAPE_KERN_INFO     KERN_INFO "viotape: "

static int viotape_numdev;

/*
 * The minor number follows the conventions of the SCSI tape drives.  The
 * rewind and mode are encoded in the minor #.  We use this struct to break
 * them out
 */
struct viot_devinfo_struct {
      int devno;
      int mode;
      int rewind;
};

#define VIOTAPOP_RESET          0
#define VIOTAPOP_FSF            1
#define VIOTAPOP_BSF            2
#define VIOTAPOP_FSR            3
#define VIOTAPOP_BSR            4
#define VIOTAPOP_WEOF           5
#define VIOTAPOP_REW            6
#define VIOTAPOP_NOP            7
#define VIOTAPOP_EOM            8
#define VIOTAPOP_ERASE          9
#define VIOTAPOP_SETBLK        10
#define VIOTAPOP_SETDENSITY    11
#define VIOTAPOP_SETPOS        12
#define VIOTAPOP_GETPOS        13
#define VIOTAPOP_SETPART       14
#define VIOTAPOP_UNLOAD        15

enum viotaperc {
      viotape_InvalidRange = 0x0601,
      viotape_InvalidToken = 0x0602,
      viotape_DMAError = 0x0603,
      viotape_UseError = 0x0604,
      viotape_ReleaseError = 0x0605,
      viotape_InvalidTape = 0x0606,
      viotape_InvalidOp = 0x0607,
      viotape_TapeErr = 0x0608,

      viotape_AllocTimedOut = 0x0640,
      viotape_BOTEnc = 0x0641,
      viotape_BlankTape = 0x0642,
      viotape_BufferEmpty = 0x0643,
      viotape_CleanCartFound = 0x0644,
      viotape_CmdNotAllowed = 0x0645,
      viotape_CmdNotSupported = 0x0646,
      viotape_DataCheck = 0x0647,
      viotape_DecompressErr = 0x0648,
      viotape_DeviceTimeout = 0x0649,
      viotape_DeviceUnavail = 0x064a,
      viotape_DeviceBusy = 0x064b,
      viotape_EndOfMedia = 0x064c,
      viotape_EndOfTape = 0x064d,
      viotape_EquipCheck = 0x064e,
      viotape_InsufficientRs = 0x064f,
      viotape_InvalidLogBlk = 0x0650,
      viotape_LengthError = 0x0651,
      viotape_LibDoorOpen = 0x0652,
      viotape_LoadFailure = 0x0653,
      viotape_NotCapable = 0x0654,
      viotape_NotOperational = 0x0655,
      viotape_NotReady = 0x0656,
      viotape_OpCancelled = 0x0657,
      viotape_PhyLinkErr = 0x0658,
      viotape_RdyNotBOT = 0x0659,
      viotape_TapeMark = 0x065a,
      viotape_WriteProt = 0x065b
};

static const struct vio_error_entry viotape_err_table[] = {
      { viotape_InvalidRange, EIO, "Internal error" },
      { viotape_InvalidToken, EIO, "Internal error" },
      { viotape_DMAError, EIO, "DMA error" },
      { viotape_UseError, EIO, "Internal error" },
      { viotape_ReleaseError, EIO, "Internal error" },
      { viotape_InvalidTape, EIO, "Invalid tape device" },
      { viotape_InvalidOp, EIO, "Invalid operation" },
      { viotape_TapeErr, EIO, "Tape error" },
      { viotape_AllocTimedOut, EBUSY, "Allocate timed out" },
      { viotape_BOTEnc, EIO, "Beginning of tape encountered" },
      { viotape_BlankTape, EIO, "Blank tape" },
      { viotape_BufferEmpty, EIO, "Buffer empty" },
      { viotape_CleanCartFound, ENOMEDIUM, "Cleaning cartridge found" },
      { viotape_CmdNotAllowed, EIO, "Command not allowed" },
      { viotape_CmdNotSupported, EIO, "Command not supported" },
      { viotape_DataCheck, EIO, "Data check" },
      { viotape_DecompressErr, EIO, "Decompression error" },
      { viotape_DeviceTimeout, EBUSY, "Device timeout" },
      { viotape_DeviceUnavail, EIO, "Device unavailable" },
      { viotape_DeviceBusy, EBUSY, "Device busy" },
      { viotape_EndOfMedia, ENOSPC, "End of media" },
      { viotape_EndOfTape, ENOSPC, "End of tape" },
      { viotape_EquipCheck, EIO, "Equipment check" },
      { viotape_InsufficientRs, EOVERFLOW, "Insufficient tape resources" },
      { viotape_InvalidLogBlk, EIO, "Invalid logical block location" },
      { viotape_LengthError, EOVERFLOW, "Length error" },
      { viotape_LibDoorOpen, EBUSY, "Door open" },
      { viotape_LoadFailure, ENOMEDIUM, "Load failure" },
      { viotape_NotCapable, EIO, "Not capable" },
      { viotape_NotOperational, EIO, "Not operational" },
      { viotape_NotReady, EIO, "Not ready" },
      { viotape_OpCancelled, EIO, "Operation cancelled" },
      { viotape_PhyLinkErr, EIO, "Physical link error" },
      { viotape_RdyNotBOT, EIO, "Ready but not beginning of tape" },
      { viotape_TapeMark, EIO, "Tape mark" },
      { viotape_WriteProt, EROFS, "Write protection error" },
      { 0, 0, NULL },
};

/* Maximum number of tapes we support */
#define VIOTAPE_MAX_TAPE      HVMAXARCHITECTEDVIRTUALTAPES
#define MAX_PARTITIONS        4

/* defines for current tape state */
#define VIOT_IDLE       0
#define VIOT_READING          1
#define VIOT_WRITING          2

/* Our info on the tapes */
static struct {
      const char *rsrcname;
      const char *type;
      const char *model;
} viotape_unitinfo[VIOTAPE_MAX_TAPE];

static struct mtget viomtget[VIOTAPE_MAX_TAPE];

static struct class *tape_class;

static struct device *tape_device[VIOTAPE_MAX_TAPE];

/*
 * maintain the current state of each tape (and partition)
 * so that we know when to write EOF marks.
 */
static struct {
      unsigned char     cur_part;
      unsigned char     part_stat_rwi[MAX_PARTITIONS];
} state[VIOTAPE_MAX_TAPE];

/* We single-thread */
static struct semaphore reqSem;

/*
 * When we send a request, we use this struct to get the response back
 * from the interrupt handler
 */
struct op_struct {
      void              *buffer;
      dma_addr_t        dmaaddr;
      size_t                  count;
      int               rc;
      int               non_blocking;
      struct completion com;
      struct device           *dev;
      struct op_struct  *next;
};

static spinlock_t op_struct_list_lock;
static struct op_struct *op_struct_list;

/* forward declaration to resolve interdependence */
static int chg_state(int index, unsigned char new_state, struct file *file);

/* procfs support */
static int proc_viotape_show(struct seq_file *m, void *v)
{
      int i;

      seq_printf(m, "viotape driver version " VIOTAPE_VERSION "\n");
      for (i = 0; i < viotape_numdev; i++) {
            seq_printf(m, "viotape device %d is iSeries resource %10.10s"
                        "type %4.4s, model %3.3s\n",
                        i, viotape_unitinfo[i].rsrcname,
                        viotape_unitinfo[i].type,
                        viotape_unitinfo[i].model);
      }
      return 0;
}

static int proc_viotape_open(struct inode *inode, struct file *file)
{
      return single_open(file, proc_viotape_show, NULL);
}

static const struct file_operations proc_viotape_operations = {
      .open       = proc_viotape_open,
      .read       = seq_read,
      .llseek           = seq_lseek,
      .release    = single_release,
};

/* Decode the device minor number into its parts */
void get_dev_info(struct inode *ino, struct viot_devinfo_struct *devi)
{
      devi->devno = iminor(ino) & 0x1F;
      devi->mode = (iminor(ino) & 0x60) >> 5;
      /* if bit is set in the minor, do _not_ rewind automatically */
      devi->rewind = (iminor(ino) & 0x80) == 0;
}

/* This is called only from the exit and init paths, so no need for locking */
static void clear_op_struct_pool(void)
{
      while (op_struct_list) {
            struct op_struct *toFree = op_struct_list;
            op_struct_list = op_struct_list->next;
            kfree(toFree);
      }
}

/* Likewise, this is only called from the init path */
static int add_op_structs(int structs)
{
      int i;

      for (i = 0; i < structs; ++i) {
            struct op_struct *new_struct =
                  kmalloc(sizeof(*new_struct), GFP_KERNEL);
            if (!new_struct) {
                  clear_op_struct_pool();
                  return -ENOMEM;
            }
            new_struct->next = op_struct_list;
            op_struct_list = new_struct;
      }
      return 0;
}

/* Allocate an op structure from our pool */
static struct op_struct *get_op_struct(void)
{
      struct op_struct *retval;
      unsigned long flags;

      spin_lock_irqsave(&op_struct_list_lock, flags);
      retval = op_struct_list;
      if (retval)
            op_struct_list = retval->next;
      spin_unlock_irqrestore(&op_struct_list_lock, flags);
      if (retval) {
            memset(retval, 0, sizeof(*retval));
            init_completion(&retval->com);
      }

      return retval;
}

/* Return an op structure to our pool */
static void free_op_struct(struct op_struct *op_struct)
{
      unsigned long flags;

      spin_lock_irqsave(&op_struct_list_lock, flags);
      op_struct->next = op_struct_list;
      op_struct_list = op_struct;
      spin_unlock_irqrestore(&op_struct_list_lock, flags);
}

/* Map our tape return codes to errno values */
int tape_rc_to_errno(int tape_rc, char *operation, int tapeno)
{
      const struct vio_error_entry *err;

      if (tape_rc == 0)
            return 0;

      err = vio_lookup_rc(viotape_err_table, tape_rc);
      printk(VIOTAPE_KERN_WARN "error(%s) 0x%04x on Device %d (%-10s): %s\n",
                  operation, tape_rc, tapeno,
                  viotape_unitinfo[tapeno].rsrcname, err->msg);
      return -err->errno;
}

/* Write */
static ssize_t viotap_write(struct file *file, const char *buf,
            size_t count, loff_t * ppos)
{
      HvLpEvent_Rc hvrc;
      unsigned short flags = file->f_flags;
      int noblock = ((flags & O_NONBLOCK) != 0);
      ssize_t ret;
      struct viot_devinfo_struct devi;
      struct op_struct *op = get_op_struct();

      if (op == NULL)
            return -ENOMEM;

      get_dev_info(file->f_path.dentry->d_inode, &devi);

      /*
       * We need to make sure we can send a request.  We use
       * a semaphore to keep track of # requests in use.  If
       * we are non-blocking, make sure we don't block on the
       * semaphore
       */
      if (noblock) {
            if (down_trylock(&reqSem)) {
                  ret = -EWOULDBLOCK;
                  goto free_op;
            }
      } else
            down(&reqSem);

      /* Allocate a DMA buffer */
      op->dev = tape_device[devi.devno];
      op->buffer = dma_alloc_coherent(op->dev, count, &op->dmaaddr,
                  GFP_ATOMIC);

      if (op->buffer == NULL) {
            printk(VIOTAPE_KERN_WARN
                        "error allocating dma buffer for len %ld\n",
                        count);
            ret = -EFAULT;
            goto up_sem;
      }

      /* Copy the data into the buffer */
      if (copy_from_user(op->buffer, buf, count)) {
            printk(VIOTAPE_KERN_WARN "tape: error on copy from user\n");
            ret = -EFAULT;
            goto free_dma;
      }

      op->non_blocking = noblock;
      init_completion(&op->com);
      op->count = count;

      hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
                  HvLpEvent_Type_VirtualIo,
                  viomajorsubtype_tape | viotapewrite,
                  HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
                  viopath_sourceinst(viopath_hostLp),
                  viopath_targetinst(viopath_hostLp),
                  (u64)(unsigned long)op, VIOVERSION << 16,
                  ((u64)devi.devno << 48) | op->dmaaddr, count, 0, 0);
      if (hvrc != HvLpEvent_Rc_Good) {
            printk(VIOTAPE_KERN_WARN "hv error on op %d\n",
                        (int)hvrc);
            ret = -EIO;
            goto free_dma;
      }

      if (noblock)
            return count;

      wait_for_completion(&op->com);

      if (op->rc)
            ret = tape_rc_to_errno(op->rc, "write", devi.devno);
      else {
            chg_state(devi.devno, VIOT_WRITING, file);
            ret = op->count;
      }

free_dma:
      dma_free_coherent(op->dev, count, op->buffer, op->dmaaddr);
up_sem:
      up(&reqSem);
free_op:
      free_op_struct(op);
      return ret;
}

/* read */
static ssize_t viotap_read(struct file *file, char *buf, size_t count,
            loff_t *ptr)
{
      HvLpEvent_Rc hvrc;
      unsigned short flags = file->f_flags;
      struct op_struct *op = get_op_struct();
      int noblock = ((flags & O_NONBLOCK) != 0);
      ssize_t ret;
      struct viot_devinfo_struct devi;

      if (op == NULL)
            return -ENOMEM;

      get_dev_info(file->f_path.dentry->d_inode, &devi);

      /*
       * We need to make sure we can send a request.  We use
       * a semaphore to keep track of # requests in use.  If
       * we are non-blocking, make sure we don't block on the
       * semaphore
       */
      if (noblock) {
            if (down_trylock(&reqSem)) {
                  ret = -EWOULDBLOCK;
                  goto free_op;
            }
      } else
            down(&reqSem);

      chg_state(devi.devno, VIOT_READING, file);

      /* Allocate a DMA buffer */
      op->dev = tape_device[devi.devno];
      op->buffer = dma_alloc_coherent(op->dev, count, &op->dmaaddr,
                  GFP_ATOMIC);
      if (op->buffer == NULL) {
            ret = -EFAULT;
            goto up_sem;
      }

      op->count = count;
      init_completion(&op->com);

      hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
                  HvLpEvent_Type_VirtualIo,
                  viomajorsubtype_tape | viotaperead,
                  HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
                  viopath_sourceinst(viopath_hostLp),
                  viopath_targetinst(viopath_hostLp),
                  (u64)(unsigned long)op, VIOVERSION << 16,
                  ((u64)devi.devno << 48) | op->dmaaddr, count, 0, 0);
      if (hvrc != HvLpEvent_Rc_Good) {
            printk(VIOTAPE_KERN_WARN "tape hv error on op %d\n",
                        (int)hvrc);
            ret = -EIO;
            goto free_dma;
      }

      wait_for_completion(&op->com);

      if (op->rc)
            ret = tape_rc_to_errno(op->rc, "read", devi.devno);
      else {
            ret = op->count;
            if (ret && copy_to_user(buf, op->buffer, ret)) {
                  printk(VIOTAPE_KERN_WARN "error on copy_to_user\n");
                  ret = -EFAULT;
            }
      }

free_dma:
      dma_free_coherent(op->dev, count, op->buffer, op->dmaaddr);
up_sem:
      up(&reqSem);
free_op:
      free_op_struct(op);
      return ret;
}

/* ioctl */
static int viotap_ioctl(struct inode *inode, struct file *file,
            unsigned int cmd, unsigned long arg)
{
      HvLpEvent_Rc hvrc;
      int ret;
      struct viot_devinfo_struct devi;
      struct mtop mtc;
      u32 myOp;
      struct op_struct *op = get_op_struct();

      if (op == NULL)
            return -ENOMEM;

      get_dev_info(file->f_path.dentry->d_inode, &devi);

      down(&reqSem);

      ret = -EINVAL;

      switch (cmd) {
      case MTIOCTOP:
            ret = -EFAULT;
            /*
             * inode is null if and only if we (the kernel)
             * made the request
             */
            if (inode == NULL)
                  memcpy(&mtc, (void *) arg, sizeof(struct mtop));
            else if (copy_from_user((char *)&mtc, (char *)arg,
                              sizeof(struct mtop)))
                  goto free_op;

            ret = -EIO;
            switch (mtc.mt_op) {
            case MTRESET:
                  myOp = VIOTAPOP_RESET;
                  break;
            case MTFSF:
                  myOp = VIOTAPOP_FSF;
                  break;
            case MTBSF:
                  myOp = VIOTAPOP_BSF;
                  break;
            case MTFSR:
                  myOp = VIOTAPOP_FSR;
                  break;
            case MTBSR:
                  myOp = VIOTAPOP_BSR;
                  break;
            case MTWEOF:
                  myOp = VIOTAPOP_WEOF;
                  break;
            case MTREW:
                  myOp = VIOTAPOP_REW;
                  break;
            case MTNOP:
                  myOp = VIOTAPOP_NOP;
                  break;
            case MTEOM:
                  myOp = VIOTAPOP_EOM;
                  break;
            case MTERASE:
                  myOp = VIOTAPOP_ERASE;
                  break;
            case MTSETBLK:
                  myOp = VIOTAPOP_SETBLK;
                  break;
            case MTSETDENSITY:
                  myOp = VIOTAPOP_SETDENSITY;
                  break;
            case MTTELL:
                  myOp = VIOTAPOP_GETPOS;
                  break;
            case MTSEEK:
                  myOp = VIOTAPOP_SETPOS;
                  break;
            case MTSETPART:
                  myOp = VIOTAPOP_SETPART;
                  break;
            case MTOFFL:
                  myOp = VIOTAPOP_UNLOAD;
                  break;
            default:
                  printk(VIOTAPE_KERN_WARN "MTIOCTOP called "
                              "with invalid op 0x%x\n", mtc.mt_op);
                  goto free_op;
            }

            /*
             * if we moved the head, we are no longer
             * reading or writing
             */
            switch (mtc.mt_op) {
            case MTFSF:
            case MTBSF:
            case MTFSR:
            case MTBSR:
            case MTTELL:
            case MTSEEK:
            case MTREW:
                  chg_state(devi.devno, VIOT_IDLE, file);
            }

            init_completion(&op->com);
            hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
                        HvLpEvent_Type_VirtualIo,
                        viomajorsubtype_tape | viotapeop,
                        HvLpEvent_AckInd_DoAck,
                        HvLpEvent_AckType_ImmediateAck,
                        viopath_sourceinst(viopath_hostLp),
                        viopath_targetinst(viopath_hostLp),
                        (u64)(unsigned long)op,
                        VIOVERSION << 16,
                        ((u64)devi.devno << 48), 0,
                        (((u64)myOp) << 32) | mtc.mt_count, 0);
            if (hvrc != HvLpEvent_Rc_Good) {
                  printk(VIOTAPE_KERN_WARN "hv error on op %d\n",
                              (int)hvrc);
                  goto free_op;
            }
            wait_for_completion(&op->com);
            ret = tape_rc_to_errno(op->rc, "tape operation", devi.devno);
            goto free_op;

      case MTIOCGET:
            ret = -EIO;
            init_completion(&op->com);
            hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
                        HvLpEvent_Type_VirtualIo,
                        viomajorsubtype_tape | viotapegetstatus,
                        HvLpEvent_AckInd_DoAck,
                        HvLpEvent_AckType_ImmediateAck,
                        viopath_sourceinst(viopath_hostLp),
                        viopath_targetinst(viopath_hostLp),
                        (u64)(unsigned long)op, VIOVERSION << 16,
                        ((u64)devi.devno << 48), 0, 0, 0);
            if (hvrc != HvLpEvent_Rc_Good) {
                  printk(VIOTAPE_KERN_WARN "hv error on op %d\n",
                              (int)hvrc);
                  goto free_op;
            }
            wait_for_completion(&op->com);

            /* Operation is complete - grab the error code */
            ret = tape_rc_to_errno(op->rc, "get status", devi.devno);
            free_op_struct(op);
            up(&reqSem);

            if ((ret == 0) && copy_to_user((void *)arg,
                              &viomtget[devi.devno],
                              sizeof(viomtget[0])))
                  ret = -EFAULT;
            return ret;
      case MTIOCPOS:
            printk(VIOTAPE_KERN_WARN "Got an (unsupported) MTIOCPOS\n");
            break;
      default:
            printk(VIOTAPE_KERN_WARN "got an unsupported ioctl 0x%0x\n",
                        cmd);
            break;
      }

free_op:
      free_op_struct(op);
      up(&reqSem);
      return ret;
}

static int viotap_open(struct inode *inode, struct file *file)
{
      HvLpEvent_Rc hvrc;
      struct viot_devinfo_struct devi;
      int ret;
      struct op_struct *op = get_op_struct();

      if (op == NULL)
            return -ENOMEM;

      get_dev_info(file->f_path.dentry->d_inode, &devi);

      /* Note: We currently only support one mode! */
      if ((devi.devno >= viotape_numdev) || (devi.mode)) {
            ret = -ENODEV;
            goto free_op;
      }

      init_completion(&op->com);

      hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
                  HvLpEvent_Type_VirtualIo,
                  viomajorsubtype_tape | viotapeopen,
                  HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
                  viopath_sourceinst(viopath_hostLp),
                  viopath_targetinst(viopath_hostLp),
                  (u64)(unsigned long)op, VIOVERSION << 16,
                  ((u64)devi.devno << 48), 0, 0, 0);
      if (hvrc != 0) {
            printk(VIOTAPE_KERN_WARN "bad rc on signalLpEvent %d\n",
                        (int) hvrc);
            ret = -EIO;
            goto free_op;
      }

      wait_for_completion(&op->com);
      ret = tape_rc_to_errno(op->rc, "open", devi.devno);

free_op:
      free_op_struct(op);
      return ret;
}


static int viotap_release(struct inode *inode, struct file *file)
{
      HvLpEvent_Rc hvrc;
      struct viot_devinfo_struct devi;
      int ret = 0;
      struct op_struct *op = get_op_struct();

      if (op == NULL)
            return -ENOMEM;
      init_completion(&op->com);

      get_dev_info(file->f_path.dentry->d_inode, &devi);

      if (devi.devno >= viotape_numdev) {
            ret = -ENODEV;
            goto free_op;
      }

      chg_state(devi.devno, VIOT_IDLE, file);

      if (devi.rewind) {
            hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
                        HvLpEvent_Type_VirtualIo,
                        viomajorsubtype_tape | viotapeop,
                        HvLpEvent_AckInd_DoAck,
                        HvLpEvent_AckType_ImmediateAck,
                        viopath_sourceinst(viopath_hostLp),
                        viopath_targetinst(viopath_hostLp),
                        (u64)(unsigned long)op, VIOVERSION << 16,
                        ((u64)devi.devno << 48), 0,
                        ((u64)VIOTAPOP_REW) << 32, 0);
            wait_for_completion(&op->com);

            tape_rc_to_errno(op->rc, "rewind", devi.devno);
      }

      hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
                  HvLpEvent_Type_VirtualIo,
                  viomajorsubtype_tape | viotapeclose,
                  HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
                  viopath_sourceinst(viopath_hostLp),
                  viopath_targetinst(viopath_hostLp),
                  (u64)(unsigned long)op, VIOVERSION << 16,
                  ((u64)devi.devno << 48), 0, 0, 0);
      if (hvrc != 0) {
            printk(VIOTAPE_KERN_WARN "bad rc on signalLpEvent %d\n",
                        (int) hvrc);
            ret = -EIO;
            goto free_op;
      }

      wait_for_completion(&op->com);

      if (op->rc)
            printk(VIOTAPE_KERN_WARN "close failed\n");

free_op:
      free_op_struct(op);
      return ret;
}

const struct file_operations viotap_fops = {
      .owner =    THIS_MODULE,
      .read =           viotap_read,
      .write =    viotap_write,
      .ioctl =    viotap_ioctl,
      .open =           viotap_open,
      .release =  viotap_release,
};

/* Handle interrupt events for tape */
static void vioHandleTapeEvent(struct HvLpEvent *event)
{
      int tapeminor;
      struct op_struct *op;
      struct viotapelpevent *tevent = (struct viotapelpevent *)event;

      if (event == NULL) {
            /* Notification that a partition went away! */
            if (!viopath_isactive(viopath_hostLp)) {
                  /* TODO! Clean up */
            }
            return;
      }

      tapeminor = event->xSubtype & VIOMINOR_SUBTYPE_MASK;
      op = (struct op_struct *)event->xCorrelationToken;
      switch (tapeminor) {
      case viotapeopen:
      case viotapeclose:
            op->rc = tevent->sub_type_result;
            complete(&op->com);
            break;
      case viotaperead:
            op->rc = tevent->sub_type_result;
            op->count = tevent->len;
            complete(&op->com);
            break;
      case viotapewrite:
            if (op->non_blocking) {
                  dma_free_coherent(op->dev, op->count,
                              op->buffer, op->dmaaddr);
                  free_op_struct(op);
                  up(&reqSem);
            } else {
                  op->rc = tevent->sub_type_result;
                  op->count = tevent->len;
                  complete(&op->com);
            }
            break;
      case viotapeop:
      case viotapegetpos:
      case viotapesetpos:
      case viotapegetstatus:
            if (op) {
                  op->count = tevent->u.op.count;
                  op->rc = tevent->sub_type_result;
                  if (!op->non_blocking)
                        complete(&op->com);
            }
            break;
      default:
            printk(VIOTAPE_KERN_WARN "weird ack\n");
      }
}

static int viotape_probe(struct vio_dev *vdev, const struct vio_device_id *id)
{
      int i = vdev->unit_address;
      int j;
      struct device_node *node = vdev->dev.archdata.of_node;

      if (i > VIOTAPE_MAX_TAPE)
            return -ENODEV;
      if (!node)
            return -ENODEV;

      if (i >= viotape_numdev)
            viotape_numdev = i + 1;

      tape_device[i] = &vdev->dev;
      viotape_unitinfo[i].rsrcname = of_get_property(node,
                              "linux,vio_rsrcname", NULL);
      viotape_unitinfo[i].type = of_get_property(node, "linux,vio_type",
                              NULL);
      viotape_unitinfo[i].model = of_get_property(node, "linux,vio_model",
                              NULL);

      state[i].cur_part = 0;
      for (j = 0; j < MAX_PARTITIONS; ++j)
            state[i].part_stat_rwi[j] = VIOT_IDLE;
      device_create(tape_class, NULL, MKDEV(VIOTAPE_MAJOR, i),
                  "iseries!vt%d", i);
      device_create(tape_class, NULL, MKDEV(VIOTAPE_MAJOR, i | 0x80),
                  "iseries!nvt%d", i);
      printk(VIOTAPE_KERN_INFO "tape iseries/vt%d is iSeries "
                  "resource %10.10s type %4.4s, model %3.3s\n",
                  i, viotape_unitinfo[i].rsrcname,
                  viotape_unitinfo[i].type, viotape_unitinfo[i].model);
      return 0;
}

static int viotape_remove(struct vio_dev *vdev)
{
      int i = vdev->unit_address;

      device_destroy(tape_class, MKDEV(VIOTAPE_MAJOR, i | 0x80));
      device_destroy(tape_class, MKDEV(VIOTAPE_MAJOR, i));
      return 0;
}

/**
 * viotape_device_table: Used by vio.c to match devices that we
 * support.
 */
static struct vio_device_id viotape_device_table[] __devinitdata = {
      { "byte", "IBM,iSeries-viotape" },
      { "", "" }
};
MODULE_DEVICE_TABLE(vio, viotape_device_table);

static struct vio_driver viotape_driver = {
      .id_table = viotape_device_table,
      .probe = viotape_probe,
      .remove = viotape_remove,
      .driver = {
            .name = "viotape",
            .owner = THIS_MODULE,
      }
};


int __init viotap_init(void)
{
      int ret;
      struct proc_dir_entry *e;

      if (!firmware_has_feature(FW_FEATURE_ISERIES))
            return -ENODEV;

      op_struct_list = NULL;
      if ((ret = add_op_structs(VIOTAPE_MAXREQ)) < 0) {
            printk(VIOTAPE_KERN_WARN "couldn't allocate op structs\n");
            return ret;
      }
      spin_lock_init(&op_struct_list_lock);

      sema_init(&reqSem, VIOTAPE_MAXREQ);

      if (viopath_hostLp == HvLpIndexInvalid) {
            vio_set_hostlp();
            if (viopath_hostLp == HvLpIndexInvalid) {
                  ret = -ENODEV;
                  goto clear_op;
            }
      }

      ret = viopath_open(viopath_hostLp, viomajorsubtype_tape,
                  VIOTAPE_MAXREQ + 2);
      if (ret) {
            printk(VIOTAPE_KERN_WARN
                        "error on viopath_open to hostlp %d\n", ret);
            ret = -EIO;
            goto clear_op;
      }

      printk(VIOTAPE_KERN_INFO "vers " VIOTAPE_VERSION
                  ", hosting partition %d\n", viopath_hostLp);

      vio_setHandler(viomajorsubtype_tape, vioHandleTapeEvent);

      ret = register_chrdev(VIOTAPE_MAJOR, "viotape", &viotap_fops);
      if (ret < 0) {
            printk(VIOTAPE_KERN_WARN "Error registering viotape device\n");
            goto clear_handler;
      }

      tape_class = class_create(THIS_MODULE, "tape");
      if (IS_ERR(tape_class)) {
            printk(VIOTAPE_KERN_WARN "Unable to allocat class\n");
            ret = PTR_ERR(tape_class);
            goto unreg_chrdev;
      }

      ret = vio_register_driver(&viotape_driver);
      if (ret)
            goto unreg_class;

      e = create_proc_entry("iSeries/viotape", S_IFREG|S_IRUGO, NULL);
      if (e) {
            e->owner = THIS_MODULE;
            e->proc_fops = &proc_viotape_operations;
      }

      return 0;

unreg_class:
      class_destroy(tape_class);
unreg_chrdev:
      unregister_chrdev(VIOTAPE_MAJOR, "viotape");
clear_handler:
      vio_clearHandler(viomajorsubtype_tape);
      viopath_close(viopath_hostLp, viomajorsubtype_tape, VIOTAPE_MAXREQ + 2);
clear_op:
      clear_op_struct_pool();
      return ret;
}

/* Give a new state to the tape object */
static int chg_state(int index, unsigned char new_state, struct file *file)
{
      unsigned char *cur_state =
          &state[index].part_stat_rwi[state[index].cur_part];
      int rc = 0;

      /* if the same state, don't bother */
      if (*cur_state == new_state)
            return 0;

      /* write an EOF if changing from writing to some other state */
      if (*cur_state == VIOT_WRITING) {
            struct mtop write_eof = { MTWEOF, 1 };

            rc = viotap_ioctl(NULL, file, MTIOCTOP,
                          (unsigned long)&write_eof);
      }
      *cur_state = new_state;
      return rc;
}

/* Cleanup */
static void __exit viotap_exit(void)
{
      remove_proc_entry("iSeries/viotape", NULL);
      vio_unregister_driver(&viotape_driver);
      class_destroy(tape_class);
      unregister_chrdev(VIOTAPE_MAJOR, "viotape");
      viopath_close(viopath_hostLp, viomajorsubtype_tape, VIOTAPE_MAXREQ + 2);
      vio_clearHandler(viomajorsubtype_tape);
      clear_op_struct_pool();
}

MODULE_LICENSE("GPL");
module_init(viotap_init);
module_exit(viotap_exit);

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