text: /* -*- 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
  
  struct viotapelpevent {
  	struct HvLpEvent event;
  	u32 reserved;
  	u16 version;
  	u16 sub_type_result;
  	u16 tape;
  	u16 flags;
  	u32 token;
  	u64 len;
  	union {
  		struct {
  			u32 tape_op;
  			u32 count;
  		} op;
  		struct {
  			u32 type;
  			u32 resid;
  			u32 dsreg;
  			u32 gstat;
  			u32 erreg;
  			u32 file_no;
  			u32 block_no;
  		} get_status;
  		struct {
  			u32 block_no;
  		} get_pos;
  	} u;
  };
  
  enum viotapesubtype {
  	viotapeopen = 0x0001,
  	viotapeclose = 0x0002,
  	viotaperead = 0x0003,
  	viotapewrite = 0x0004,
  	viotapegetinfo = 0x0005,
  	viotapeop = 0x0006,
  	viotapegetpos = 0x0007,
  	viotapesetpos = 0x0008,
  	viotapegetstatus = 0x0009
  };
  
  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 */
  struct tape_descr {
  	char rsrcname[10];
  	char type[4];
  	char model[3];
  };
  
  static struct tape_descr *viotape_unitinfo;
  static dma_addr_t viotape_unitinfo_token;
  
  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;
  }
  
  /* Get info on all tapes from OS/400 */
  static int get_viotape_info(void)
  {
  	HvLpEvent_Rc hvrc;
  	int i;
  	size_t len = sizeof(*viotape_unitinfo) * VIOTAPE_MAX_TAPE;
  	struct op_struct *op = get_op_struct();
  
  	if (op == NULL)
  		return -ENOMEM;
  
  	viotape_unitinfo = dma_alloc_coherent(iSeries_vio_dev, len,
  		&viotape_unitinfo_token, GFP_ATOMIC);
  	if (viotape_unitinfo == NULL) {
  		free_op_struct(op);
  		return -ENOMEM;
  	}
  
  	memset(viotape_unitinfo, 0, len);
  
  	hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
  			HvLpEvent_Type_VirtualIo,
  			viomajorsubtype_tape | viotapegetinfo,
  			HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
  			viopath_sourceinst(viopath_hostLp),
  			viopath_targetinst(viopath_hostLp),
  			(u64) (unsigned long) op, VIOVERSION << 16,
  			viotape_unitinfo_token, len, 0, 0);
  	if (hvrc != HvLpEvent_Rc_Good) {
  		printk(VIOTAPE_KERN_WARN "hv error on op %d\n",
  				(int)hvrc);
  		free_op_struct(op);
  		return -EIO;
  	}
  
  	wait_for_completion(&op->com);
  
  	free_op_struct(op);
  
  	for (i = 0;
  	     ((i < VIOTAPE_MAX_TAPE) && (viotape_unitinfo[i].rsrcname[0]));
  	     i++)
  		viotape_numdev++;
  	return 0;
  }
  
  
  /* 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 viotapegetinfo:
  	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;
  
  	if (i >= viotape_numdev)
  		return -ENODEV;
  
  	tape_device[i] = &vdev->dev;
  
  	state[i].cur_part = 0;
  	for (j = 0; j < MAX_PARTITIONS; ++j)
  		state[i].part_stat_rwi[j] = VIOT_IDLE;
  	class_device_create(tape_class, NULL, MKDEV(VIOTAPE_MAJOR, i), NULL,
  			"iseries!vt%d", i);
  	class_device_create(tape_class, NULL, MKDEV(VIOTAPE_MAJOR, i | 0x80),
  			NULL, "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;
  
  	class_device_destroy(tape_class, MKDEV(VIOTAPE_MAJOR, i | 0x80));
  	class_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;
  	}
  
  	if ((ret = get_viotape_info()) < 0) {
  		printk(VIOTAPE_KERN_WARN "Unable to obtain virtual device information");
  		goto unreg_class;
  	}
  
  	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)
  {
  	int ret;
  
  	remove_proc_entry("iSeries/viotape", NULL);
  	vio_unregister_driver(&viotape_driver);
  	class_destroy(tape_class);
  	ret = unregister_chrdev(VIOTAPE_MAJOR, "viotape");
  	if (ret < 0)
  		printk(VIOTAPE_KERN_WARN "Error unregistering device: %d\n",
  				ret);
  	if (viotape_unitinfo)
  		dma_free_coherent(iSeries_vio_dev,
  				sizeof(viotape_unitinfo[0]) * VIOTAPE_MAX_TAPE,
  				viotape_unitinfo, viotape_unitinfo_token);
  	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);
  