[PATCH] ppc64: iSeries virtual tape driver

From: Stephen Rothwell <sfr@canb.auug.org.au>

This patch adds the driver for the PPC64 iSeries virtual tape.

drivers/char/Makefile

@@ -44,6 +44,7 @@ obj-$(CONFIG_HVC_CONSOLE)	+= hvc_console.o
 obj-$(CONFIG_RAW_DRIVER)	+= raw.o
 obj-$(CONFIG_SGI_L1_SERIAL)	+= sn_serial.o
 obj-$(CONFIG_VIOCONS) += viocons.o
+obj-$(CONFIG_VIOTAPE)		+= viotape.o
 
 obj-$(CONFIG_PRINTER) += lp.o
 obj-$(CONFIG_TIPAR) += tipar.o

drivers/char/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/config.h>
+#include <linux/version.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/devfs_fs_kernel.h>
+#include <linux/major.h>
+#include <linux/completion.h>
+
+#include <asm/uaccess.h>
+#include <asm/ioctls.h>
+
+#include <asm/iSeries/vio.h>
+#include <asm/iSeries/HvLpEvent.h>
+#include <asm/iSeries/HvCallEvent.h>
+#include <asm/iSeries/HvLpConfig.h>
+
+#define VIOTAPE_VERSION		"1.1"
+#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	8
+#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_simple *tape_class;
+
+/*
+ * maintain the current state of each tape (and partition)
+ * so that we know when to write EOF marks.
+ */
+static struct {
+	unsigned char	cur_part;
+	int		dev_handle;
+	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 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);
+
+/* 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_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->buffer = dma_alloc_coherent(iSeries_vio_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(iSeries_vio_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_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->buffer = dma_alloc_coherent(iSeries_vio_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(iSeries_vio_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_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_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_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;
+}
+
+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(iSeries_vio_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 "wierd ack\n");
+	}
+}
+
+
+int __init viotap_init(void)
+{
+	int ret;
+	char tapename[32];
+	int i;
+
+	printk(VIOTAPE_KERN_INFO "driver version " VIOTAPE_VERSION "\n");
+
+	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;
+		}
+	}
+
+	printk(VIOTAPE_KERN_INFO "init - open path to hosting (%d)\n",
+			viopath_hostLp);
+	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;
+	}
+
+	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_simple_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;
+	}
+
+	for (i = 0; i < viotape_numdev; i++) {
+		int j;
+
+		state[i].cur_part = 0;
+		for (j = 0; j < MAX_PARTITIONS; ++j)
+			state[i].part_stat_rwi[j] = VIOT_IDLE;
+		class_simple_device_add(tape_class, MKDEV(VIOTAPE_MAJOR, i),
+				NULL, "iseries!vt%d", i);
+		class_simple_device_add(tape_class,
+				MKDEV(VIOTAPE_MAJOR, i | 0x80),
+				NULL, "iseries!nvt%d", i);
+		devfs_mk_cdev(MKDEV(VIOTAPE_MAJOR, i),
+				S_IFCHR | S_IRUSR | S_IWUSR,
+				"iseries/vt%d", i);
+		devfs_mk_cdev(MKDEV(VIOTAPE_MAJOR, i | 0x80),
+				S_IFCHR | S_IRUSR | S_IWUSR,
+				"iseries/nvt%d", i);
+		sprintf(tapename, "iseries/vt%d", i);
+		state[i].dev_handle = devfs_register_tape(tapename);
+		printk(VIOTAPE_KERN_INFO "tape %s is iSeries "
+				"resource %10.10s type %4.4s, model %3.3s\n",
+				tapename, viotape_unitinfo[i].rsrcname,
+				viotape_unitinfo[i].type,
+				viotape_unitinfo[i].model);
+	}
+
+	return 0;
+
+unreg_class:
+	class_simple_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 i, ret;
+
+	for (i = 0; i < viotape_numdev; ++i) {
+		devfs_remove("iseries/nvt%d", i);
+		devfs_remove("iseries/vt%d", i);
+		devfs_unregister_tape(state[i].dev_handle);
+		class_simple_device_remove(MKDEV(VIOTAPE_MAJOR, i | 0x80));
+		class_simple_device_remove(MKDEV(VIOTAPE_MAJOR, i));
+	}
+	class_simple_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);

include/linux/major.h

@@ -163,4 +163,6 @@
 #define IBM_TTY3270_MAJOR	227
 #define IBM_FS3270_MAJOR	228
 
+#define VIOTAPE_MAJOR		230
+
 #endif