viotape.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,130 行 · 第 1/2 页

/* -*- linux-c -*-
 *  drivers/char/viotape.c
 *
 *  iSeries Virtual Tape
 *
 *  Authors: Dave Boutcher <[e-mail]>
 *           Ryan Arnold <[e-mail]>
 *           Colin Devilbiss <[e-mail]>
 *           Stephen Rothwell <[e-mail]>
 *
 * (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 <linux/proc_fs.h>
#include <linux/seq_file.h>

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

#include <asm/vio.h>
#include <asm/iSeries/vio.h>
#include <asm/iSeries/HvLpEvent.h>
#include <asm/iSeries/HvCallEvent.h>
#include <asm/iSeries/HvLpConfig.h>

#define VIOTAPE_VERSION		"1.2"
#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_simple *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;
	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 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 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_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_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;
	}