tpqic02.c

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/* $Id: tpqic02.c,v 1.10 1997/01/26 07:13:20 davem Exp $
 *
 * Driver for tape drive support for Linux-i386
 *
 * Copyright (c) 1992--1996 by H. H. Bergman. All rights reserved.
 * Current e-mail address: [e-mail]
 *
 * Distribution of this program in executable form is only allowed if
 * all of the corresponding source files are made available through the same
 * medium at no extra cost.
 *
 * I will not accept any responsibility for damage caused directly or
 * indirectly by this program, or code derived from this program.
 *
 * Use this code at your own risk. Don't blame me if it destroys your data!
 * Make sure you have a backup before you try this code.
 *
 * If you make changes to my code and redistribute it in source or binary
 * form you must make it clear to even casual users of your code that you
 * have modified my code, clearly point out what the changes exactly are
 * (preferably in the form of a context diff file), how to undo your changes,
 * where the original can be obtained, and that complaints/requests about the
 * modified code should be directed to you instead of me.
 *
 * This driver was partially inspired by the 'wt' driver in the 386BSD
 * source distribution, which carries the following copyright notice:
 *
 *  Copyright (c) 1991 The Regents of the University of California.
 *  All rights reserved.
 *
 * You are not allowed to change this line nor the text above.
 *
 * 2001/02/26	Minor s/suser/capable/
 *
 * 1996/10/10   Emerald changes
 *
 * 1996/05/21	Misc changes+merges+cleanups + I/O reservations
 *
 * 1996/05/20	Module support patches submitted by Brian McCauley.
 *
 * 1994/05/03	Initial attempt at Mountain support for the Mountain 7150.
 * Based on patches provided by Erik Jacobson. Still incomplete, I suppose.
 *
 * 1994/02/07	Archive changes & some cleanups by Eddy Olk.
 *
 * 1994/01/19	Speed measuring stuff moved from aperf.h to delay.h.
 *		BogoMips (tm) introduced by Linus.
 *
 * 1993/01/25	Kernel udelay. Eof fixups.
 * 
 * 1992/09/19	Some changes based on patches by Eddy Olk to support
 * 		Archive SC402/SC499R controller cards.
 *
 * 1992/05/27	First release.
 *
 * 1992/05/26	Initial version. Copyright H. H. Bergman 1992
 */

/* After the legalese, now the important bits:
 * 
 * This is a driver for the Wangtek 5150 tape drive with 
 * a QIC-02 controller for ISA-PC type computers.
 * Hopefully it will work with other QIC-02 tape drives as well.
 *
 * Make sure your setup matches the configuration parameters.
 * Also, be careful to avoid IO conflicts with other devices!
 */


/*
#define TDEBUG
*/

#define REALLY_SLOW_IO		/* it sure is ... */

#include <linux/module.h>

#include <linux/config.h>

#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/errno.h>
#include <linux/mtio.h>
#include <linux/fcntl.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/tpqic02.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <linux/devfs_fs_kernel.h>

#include <asm/dma.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/uaccess.h>

/* check existence of required configuration parameters */
#if !defined(QIC02_CMD_PORT) || !defined(QIC02_TAPE_IRQ) || !defined(QIC02_TAPE_DMA)
# error qic02_tape configuration error
#endif


#define TPQIC02_NAME	"tpqic02"

/* Linux outb() commands have (value,port) as parameters.
 * One might expect (port,value) instead, so beware!
 */

#ifdef CONFIG_QIC02_DYNCONF
/* This holds the dynamic configuration info for the interface
 * card+drive info if runtime configuration has been selected.
 */

static struct mtconfiginfo qic02_tape_dynconf =	/* user settable */
{ 0, 0, BOGUS_IRQ, 0, 0, TPQD_DEFAULT_FLAGS, };
static struct qic02_ccb qic02_tape_ccb;	/* private stuff */

#else

unsigned long qic02_tape_debug = TPQD_DEFAULT_FLAGS;

# if ((QIC02_TAPE_IFC!=WANGTEK) && (QIC02_TAPE_IFC!=ARCHIVE) && (QIC02_TAPE_IFC!=MOUNTAIN))
#  error No valid interface card specified
# endif
#endif				/* CONFIG_QIC02_DYNCONF */

static volatile int ctlbits;	/* control reg bits for tape interface */

static wait_queue_head_t qic02_tape_transfer;	/* sync rw with interrupts */

static volatile struct mtget ioctl_status;	/* current generic status */

static volatile struct tpstatus tperror;	/* last drive status */

static char rcs_revision[] = "$Revision: 1.10 $";
static char rcs_date[] = "$Date: 1997/01/26 07:13:20 $";

/* Flag bits for status and outstanding requests.
 * (Could all be put in one bit-field-struct.)
 * Some variables need `volatile' because they may be modified
 * by an interrupt.
 */
static volatile flag status_dead = YES;	/* device is legally dead until proven alive */
static flag status_zombie = YES;	/* it's `zombie' until irq/dma allocated */

static volatile flag status_bytes_wr = NO;	/* write FM at close or not */
static volatile flag status_bytes_rd = NO;	/* (rd|wr) used for rewinding */

static volatile unsigned long status_cmd_pending;	/* cmd in progress */
static volatile flag status_expect_int = NO;	/* ready for interrupts */
static volatile flag status_timer_on = NO;	/* using time-out */
static volatile int status_error;	/* int handler may detect error */
static volatile flag status_eof_detected = NO;	/* end of file */
static volatile flag status_eom_detected = NO;	/* end of recorded media */
static volatile flag status_eot_detected = NO;	/* end of tape */
static volatile flag doing_read = NO;
static volatile flag doing_write = NO;

static volatile unsigned long dma_bytes_todo;
static volatile unsigned long dma_bytes_done;
static volatile unsigned dma_mode;	/* !=0 also means DMA in use */
static flag need_rewind = YES;

static kdev_t current_tape_dev;
static int extra_blocks_left = BLOCKS_BEYOND_EW;

static struct timer_list tp_timer;

/* return_*_eof:
 *	NO:	not at EOF,
 *	YES:	tell app EOF was reached (return 0).
 *
 * return_*_eof==YES && reported_*_eof==NO  ==>
 *	return current buffer, next time(s) return EOF.
 *
 * return_*_eof==YES && reported_*_eof==YES  ==>
 *	at EOF and application knows it, so we can
 *	move on to the next file.
 *
 */
static flag return_read_eof = NO;	/* set to signal app EOF was reached */
static flag return_write_eof = NO;
static flag reported_read_eof = NO;	/* set when we've done that */
static flag reported_write_eof = NO;


/* This is for doing `mt seek <blocknr>' */
static char seek_addr_buf[AR_SEEK_BUF_SIZE];


/* In write mode, we have to write a File Mark after the last block written, 
 * when the tape device is closed. Tape repositioning and reading in write
 * mode is allowed as long as no actual writing has been done. After writing
 * the File Mark, repositioning and reading are allowed again.
 */
static int mode_access;		/* access mode: READ or WRITE */

static int qic02_get_resources(void);
static void qic02_release_resources(void);

/* This is a pointer to the actual kernel buffer where the interrupt routines
 * read from/write to. It is needed because the DMA channels 1 and 3 cannot
 * always access the user buffers. [The kernel buffer must reside in the
 * lower 16MBytes of system memory because of the DMA controller.] The user
 * must ensure that a large enough buffer is passed to the kernel, in order
 * to reduce tape repositioning wear and tear.
 */
static void *buffaddr;		/* virtual address of buffer */

/* This translates minor numbers to the corresponding recording format: */
static const char *format_names[] = {
	"not set",		/* for dumb drives unable to handle format selection */
	"11",			/* extinct */
	"24",
	"120",
	"150",
	"300",			/* untested. */
	"600"			/* untested. */
};


/* `exception_list' is needed for exception status reporting.
 * Exceptions 1..14 are defined by QIC-02 rev F.
 * The drive status is matched sequentially to each entry,
 * ignoring irrelevant bits, until a match is found. If no
 * match is found, exception number 0 is used. (That should of
 * course never happen...) The original table was based on the
 * "Exception Status Summary" in QIC-02 rev F, but some changes
 * were required to make it work with real-world drives.
 *
 * Exception 2 (CNI) is changed to also cover status 0x00e0 (mask USL),
 * Exception 4 (EOM) is changed to also cover status 0x8288 (mask EOR),
 * Exception 11 (FIL) is changed to also cover status 0x0089 (mask EOM).
 * Exception 15 (EOR) is added for seek-to-end-of-data (catch EOR),
 * Exception 16 (BOM) is added for beginning-of-media (catch BOM).
 *
 * Had to swap EXC_NDRV and EXC_NCART to ensure that extended EXC_NCART
 * (because of the incorrect Wangtek status code) doesn't catch the
 * EXC_NDRV first.
 */
static struct exception_list_type {
	unsigned short mask, code;
	const char *msg;
	/* EXC_nr attribute should match with tpqic02.h */
} exception_list[] = {
	{
	0, 0, "Unknown exception status code", /* extra: 0 */ },
	{
	~(0), TP_ST0 | TP_CNI | TP_USL | TP_WRP,
		    "Drive not online" /* 1 */ },
	    /* Drive presence goes before cartridge presence. */
	{
		~(TP_WRP | TP_USL), TP_ST0 | TP_CNI,
		    /* My Wangtek 5150EQ sometimes reports a status code
		     * of 0x00e0, which is not a valid exception code, but
		     * I think it should be recognized as "NO CARTRIDGE".
		     */
	"Cartridge not in place" /* 2 */ },
	{
	(unsigned short) ~(TP_ST1 | TP_BOM), (TP_ST0 | TP_WRP),
		    "Write protected cartridge" /* 3 */ },
	{
	(unsigned short) ~(TP_ST1 | TP_EOR), (TP_ST0 | TP_EOM),
		    "End of media" /* 4 */ },
	{
	~TP_WRP, TP_ST0 | TP_UDA | TP_ST1 | TP_BOM,
		    "Read or Write abort. Rewind tape." /* 5 */ },
	{
	~TP_WRP, TP_ST0 | TP_UDA,
		    "Read error. Bad block transferred." /* 6 */ },
	{
	~TP_WRP, TP_ST0 | TP_UDA | TP_BNL,
		    "Read error. Filler block transferred." /* 7 */ },
	{
	~TP_WRP, TP_ST0 | TP_UDA | TP_BNL | TP_ST1 | TP_NDT,
		    "Read error. No data detected." /* 8 */ },
	{
	~TP_WRP,
		    TP_ST0 | TP_EOM | TP_UDA | TP_BNL | TP_ST1 |
		    TP_NDT, "Read error. No data detected. EOM." /* 9 */ },
	{
	~(TP_WRP | TP_MBD | TP_PAR | TP_EOR),
		    TP_ST0 | TP_UDA | TP_BNL | TP_ST1 | TP_NDT |
		    TP_BOM,
		    "Read error. No data detected. BOM." /* 10 */ },
	{
		~(TP_WRP | TP_EOM), TP_ST0 | TP_FIL,
		    /* Status 0x0089 (EOM & FM) is viewed as an FM,
		     * because it can only happen during a read.
		     * EOM is checked separately for an FM condition.
		     */
	"File mark detected" /* 11 */ },
	{
	~(TP_ST0 | TP_CNI | TP_USL | TP_WRP | TP_BOM),
		    TP_ST1 | TP_ILL, "Illegal command" /* 12 */ },
	{
	~(TP_ST0 | TP_CNI | TP_USL | TP_WRP | TP_BOM),
		    TP_ST1 | TP_POR, "Reset occurred" /* 13 */ },
	{
		~TP_WRP, TP_ST0 | TP_FIL | TP_MBD,	/* NOTE: ST1 not set! */
	"Marginal block detected" /* 14 */ },
	{
		~(TP_ST0 | TP_WRP | TP_EOM | TP_UDA | TP_BNL | TP_FIL |
		  TP_NDT), TP_ST1 | TP_EOR,
		/********** Is the extra TP_NDT really needed Eddy? **********/
	"End of recorded media" /* extra: 15 */ },
	    /* 15 is returned when SEEKEOD completes successfully */
	{
	~(TP_WRP | TP_ST0), TP_ST1 | TP_BOM, "Beginning of media" /* extra: 16 */ }
};

#define NR_OF_EXC	(sizeof(exception_list)/sizeof(struct exception_list_type))

/* Compare expected struct size and actual struct size. This
 * is useful to catch programs compiled with old #includes.
 */
#define CHECK_IOC_SIZE(structure) \
	if (_IOC_SIZE(iocmd) != sizeof(struct structure)) { \
		tpqputs(TPQD_ALWAYS, "sizeof(struct " #structure \
			") does not match!"); \
		return -EFAULT; \
	} \

static void tpqputs(unsigned long flags, const char *s)
{
	if ((flags & TPQD_ALWAYS) || (flags & QIC02_TAPE_DEBUG))
		printk(TPQIC02_NAME ": %s\n", s);
}				/* tpqputs */


/* Perform byte order swapping for a 16-bit word.
 *
 * [FIXME] This should probably be in include/asm/
 * ([FIXME] i486 can do this faster)
 */
static inline void byte_swap_w(volatile unsigned short *w)
{
	int t = *w;
	*w = (t >> 8) | ((t & 0xff) << 8);
}



/* Init control register bits on interface card.
 * For Archive, interrupts must be enabled explicitly.
 * Wangtek interface card requires ONLINE to be set, Archive SC402/SC499R
 * cards keep it active all the time.
 */
static void ifc_init(void)
{
	if (QIC02_TAPE_IFC == WANGTEK) {	/* || (QIC02_TAPE_IFC == EVEREX) */
		ctlbits = WT_CTL_ONLINE;	/* online */
		outb_p(ctlbits, QIC02_CTL_PORT);
	} else if (QIC02_TAPE_IFC == ARCHIVE) {
		ctlbits = 0;	/* no interrupts yet */
		outb_p(ctlbits, QIC02_CTL_PORT);
		outb_p(0, AR_RESET_DMA_PORT);	/* dummy write to reset DMA */
	} else {		/* MOUNTAIN */

		ctlbits = MTN_CTL_ONLINE;	/* online, and logic enabled */
		outb_p(ctlbits, QIC02_CTL_PORT);
	}
}				/* ifc_init */


static void report_qic_exception(unsigned n)
{
	if (n >= NR_OF_EXC) {
		tpqputs(TPQD_ALWAYS, "Oops -- report_qic_exception");
		n = 0;
	}
	if (TPQDBG(SENSE_TEXT) || n == 0) {
		printk(TPQIC02_NAME ": sense: %s\n",
		       exception_list[n].msg);
	}
}				/* report_qic_exception */


/* Try to map the drive-exception bits `s' to a predefined "exception number",
 * by comparing the significant exception bits for each entry in the
 * exception table (`exception_list[]').
 * It is assumed that s!=0.
 */
static int decode_qic_exception_nr(unsigned s)
{
	int i;

	for (i = 1; i < NR_OF_EXC; i++) {
		if ((s & exception_list[i].mask) == exception_list[i].code) {
			return i;
		}
	}
	printk(TPQIC02_NAME
	       ": decode_qic_exception_nr: exception(%x) not recognized\n",
	       s);
	return 0;
}				/* decode_qic_exception_nr */



/* Perform appropriate action for certain exceptions.
 * should return a value to indicate stop/continue (in case of bad blocks)
 */
static void handle_qic_exception(int exnr, int exbits)
{
	if (exnr == EXC_NCART) {
		/* Cartridge was changed. Redo sense().
		 * EXC_NCART should be handled in open().
		 * It is not permitted to remove the tape while
		 * the tape driver has open files. 
		 */
		need_rewind = YES;
		status_eof_detected = NO;
		status_eom_detected = NO;
	} else if (exnr == EXC_XFILLER) {
		tpqputs(TPQD_ALWAYS,
			"[Bad block -- filler data transferred.]");
	} else if (exnr == EXC_XBAD) {
		tpqputs(TPQD_ALWAYS, "[CRC failed!]");
	} else if (exnr == EXC_MARGINAL) {