/*
 * acsi.c -- Device driver for Atari ACSI hard disks
 *
 * Copyright 1994 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
 *
 * Some parts are based on hd.c by Linus Torvalds
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive for
 * more details.
 *
 */

/*
 * Still to in this file:
 *  - If a command ends with an error status (!= 0), the following
 *    REQUEST SENSE commands (4 to fill the ST-DMA FIFO) are done by
 *    polling the _IRQ signal (not interrupt-driven). This should be
 *    avoided in future because it takes up a non-neglectible time in
 *    the interrupt service routine while interrupts are disabled.
 *    Maybe a timer interrupt will get lost :-(
 */

/*
 * General notes:
 *
 *  - All ACSI devices (disks, CD-ROMs, ...) use major number 28.
 *    Minors are organized like it is with SCSI: The upper 4 bits
 *    identify the device, the lower 4 bits the partition.
 *    The device numbers (the upper 4 bits) are given in the same
 *    order as the devices are found on the bus.
 *  - Up to 8 LUNs are supported for each target (if CONFIG_ACSI_MULTI_LUN
 *    is defined), but only a total of 16 devices (due to minor
 *    numbers...). Note that Atari allows only a maximum of 4 targets
 *    (i.e. controllers, not devices) on the ACSI bus!
 *  - A optimizing scheme similar to SCSI scatter-gather is implemented.
 *  - Removable media are supported. After a medium change to device
 *    is reinitialized (partition check etc.). Also, if the device
 *    knows the PREVENT/ALLOW MEDIUM REMOVAL command, the door should
 *    be locked and unlocked when mounting the first or unmounting the
 *    last filesystem on the device. The code is untested, because I
 *    don't have a removable hard disk.
 *
 */

#define MAJOR_NR ACSI_MAJOR

#include <linux/config.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/genhd.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/delay.h>
#include <linux/mm.h>
#include <linux/major.h>
#include <linux/blk.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <scsi/scsi.h> /* for SCSI_IOCTL_GET_IDLUN */
typedef void Scsi_Device; /* hack to avoid including scsi.h */
#include <scsi/scsi_ioctl.h>
#include <linux/hdreg.h> /* for HDIO_GETGEO */
#include <linux/blkpg.h>

#include <asm/setup.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/atarihw.h>
#include <asm/atariints.h>
#include <asm/atari_acsi.h>
#include <asm/atari_stdma.h>
#include <asm/atari_stram.h>


#define DEBUG
#undef DEBUG_DETECT
#undef NO_WRITE

#define MAX_ERRORS              8       /* Max read/write errors/sector */
#define MAX_LUN                         8       /* Max LUNs per target */
#define MAX_DEV                         16

#define ACSI_BUFFER_SIZE                        (16*1024) /* "normal" ACSI buffer size */
#define ACSI_BUFFER_MINSIZE                     (2048)    /* min. buf size if ext. DMA */
#define ACSI_BUFFER_SIZE_ORDER          2                 /* order size for above */
#define ACSI_BUFFER_MINSIZE_ORDER       0                 /* order size for above */
#define ACSI_BUFFER_SECTORS     (ACSI_BUFFER_SIZE/512)

#define ACSI_BUFFER_ORDER \
        (ATARIHW_PRESENT(EXTD_DMA) ? \
         ACSI_BUFFER_MINSIZE_ORDER : \
         ACSI_BUFFER_SIZE_ORDER)

#define ACSI_TIMEOUT            (4*HZ)

/* minimum delay between two commands */

#define COMMAND_DELAY 500

typedef enum {
        NONE, HARDDISK, CDROM
} ACSI_TYPE;

struct acsi_info_struct {
        ACSI_TYPE               type;                   /* type of device */
        unsigned                target;                 /* target number */
        unsigned                lun;                    /* LUN in target controller */
        unsigned                removable : 1;  /* Flag for removable media */
        unsigned                read_only : 1;  /* Flag for read only devices */
        unsigned                old_atari_disk : 1; /* Is an old Atari disk       */
        unsigned                changed : 1;    /* Medium has been changed */
        unsigned long   size;                   /* #blocks */
} acsi_info[MAX_DEV];

/*
 *      SENSE KEYS
 */

#define NO_SENSE                0x00
#define RECOVERED_ERROR         0x01
#define NOT_READY               0x02
#define MEDIUM_ERROR            0x03
#define HARDWARE_ERROR          0x04
#define ILLEGAL_REQUEST         0x05
#define UNIT_ATTENTION          0x06
#define DATA_PROTECT            0x07
#define BLANK_CHECK             0x08
#define COPY_ABORTED            0x0a
#define ABORTED_COMMAND         0x0b
#define VOLUME_OVERFLOW         0x0d
#define MISCOMPARE              0x0e


/*
 *      DEVICE TYPES
 */

#define TYPE_DISK       0x00
#define TYPE_TAPE       0x01
#define TYPE_WORM       0x04
#define TYPE_ROM        0x05
#define TYPE_MOD        0x07
#define TYPE_NO_LUN     0x7f

/* The data returned by MODE SENSE differ between the old Atari
 * hard disks and SCSI disks connected to ACSI. In the following, both
 * formats are defined and some macros to operate on them potably.
 */

typedef struct {
        unsigned long   dummy[2];
        unsigned long   sector_size;
        unsigned char   format_code;
#define ATARI_SENSE_FORMAT_FIX  1       
#define ATARI_SENSE_FORMAT_CHNG 2
        unsigned char   cylinders_h;
        unsigned char   cylinders_l;
        unsigned char   heads;
        unsigned char   reduced_h;
        unsigned char   reduced_l;
        unsigned char   precomp_h;
        unsigned char   precomp_l;
        unsigned char   landing_zone;
        unsigned char   steprate;
        unsigned char   type;
#define ATARI_SENSE_TYPE_FIXCHNG_MASK           4
#define ATARI_SENSE_TYPE_SOFTHARD_MASK          8
#define ATARI_SENSE_TYPE_FIX                            4
#define ATARI_SENSE_TYPE_CHNG                           0
#define ATARI_SENSE_TYPE_SOFT                           0
#define ATARI_SENSE_TYPE_HARD                           8
        unsigned char   sectors;
} ATARI_SENSE_DATA;

#define ATARI_CAPACITY(sd) \
        (((int)((sd).cylinders_h<<8)|(sd).cylinders_l) * \
         (sd).heads * (sd).sectors)


typedef struct {
        unsigned char   dummy1;
        unsigned char   medium_type;
        unsigned char   dummy2;
        unsigned char   descriptor_size;
        unsigned long   block_count;
        unsigned long   sector_size;
        /* Page 0 data */
        unsigned char   page_code;
        unsigned char   page_size;
        unsigned char   page_flags;
        unsigned char   qualifier;
} SCSI_SENSE_DATA;

#define SCSI_CAPACITY(sd)       ((sd).block_count & 0xffffff)


typedef union {
        ATARI_SENSE_DATA        atari;
        SCSI_SENSE_DATA         scsi;
} SENSE_DATA;

#define SENSE_TYPE_UNKNOWN      0
#define SENSE_TYPE_ATARI        1
#define SENSE_TYPE_SCSI         2

#define SENSE_TYPE(sd)                                                                          \
        (((sd).atari.dummy[0] == 8 &&                                                   \
          ((sd).atari.format_code == 1 ||                                               \
           (sd).atari.format_code == 2)) ? SENSE_TYPE_ATARI :   \
         ((sd).scsi.dummy1 >= 11) ? SENSE_TYPE_SCSI :                   \
         SENSE_TYPE_UNKNOWN)
         
#define CAPACITY(sd)                                                    \
        (SENSE_TYPE(sd) == SENSE_TYPE_ATARI ?           \
         ATARI_CAPACITY((sd).atari) :                           \
         SCSI_CAPACITY((sd).scsi))

#define SECTOR_SIZE(sd)                                                 \
        (SENSE_TYPE(sd) == SENSE_TYPE_ATARI ?           \
         (sd).atari.sector_size :                                       \
         (sd).scsi.sector_size & 0xffffff)

/* Default size if capacity cannot be determined (1 GByte) */
#define DEFAULT_SIZE    0x1fffff

#define CARTRCH_STAT(dev,buf)                                   \
        (acsi_info[(dev)].old_atari_disk ?                      \
         (((buf)[0] & 0x7f) == 0x28) :                                  \
         ((((buf)[0] & 0x70) == 0x70) ?                                 \
          (((buf)[2] & 0x0f) == 0x06) :                                 \
          (((buf)[0] & 0x0f) == 0x06)))                                 \

/* These two are also exported to other drivers that work on the ACSI bus and
 * need an ST-RAM buffer. */
char                    *acsi_buffer;
unsigned long   phys_acsi_buffer;

static int                              NDevices = 0;
static int                              acsi_sizes[MAX_DEV<<4] = { 0, };
static int                              acsi_blocksizes[MAX_DEV<<4] = { 0, };
static struct hd_struct acsi_part[MAX_DEV<<4] = { {0,0}, };
static int                              access_count[MAX_DEV] = { 0, };
static char                     busy[MAX_DEV] = { 0, };
static DECLARE_WAIT_QUEUE_HEAD(busy_wait);

static int                              CurrentNReq;
static int                              CurrentNSect;
static char                             *CurrentBuffer;


#define SET_TIMER()     mod_timer(&acsi_timer, jiffies + ACSI_TIMEOUT)
#define CLEAR_TIMER()   del_timer(&acsi_timer)

static unsigned long    STramMask;
#define STRAM_ADDR(a)   (((a) & STramMask) == 0)



/* ACSI commands */

static char tur_cmd[6]        = { 0x00, 0, 0, 0, 0, 0 };
static char modesense_cmd[6]  = { 0x1a, 0, 0, 0, 24, 0 };
static char modeselect_cmd[6] = { 0x15, 0, 0, 0, 12, 0 };
static char inquiry_cmd[6]    = { 0x12, 0, 0, 0,255, 0 };
static char reqsense_cmd[6]   = { 0x03, 0, 0, 0, 4, 0 };
static char read_cmd[6]       = { 0x08, 0, 0, 0, 0, 0 };
static char write_cmd[6]      = { 0x0a, 0, 0, 0, 0, 0 };
static char pa_med_rem_cmd[6] = { 0x1e, 0, 0, 0, 0, 0 };

#define CMDSET_TARG_LUN(cmd,targ,lun)                   \
    do {                                                \
                cmd[0] = (cmd[0] & ~0xe0) | (targ)<<5;  \
                cmd[1] = (cmd[1] & ~0xe0) | (lun)<<5;   \
        } while(0)

#define CMDSET_BLOCK(cmd,blk)                                           \
    do {                                                                                        \
                unsigned long __blk = (blk);                            \
                cmd[3] = __blk; __blk >>= 8;                            \
                cmd[2] = __blk; __blk >>= 8;                            \
                cmd[1] = (cmd[1] & 0xe0) | (__blk & 0x1f);      \
        } while(0)

#define CMDSET_LEN(cmd,len)                                             \
        do {                                                                            \
                cmd[4] = (len);                                                 \
        } while(0)

/* ACSI errors (from REQUEST SENSE); There are two tables, one for the
 * old Atari disks and one for SCSI on ACSI disks.
 */

struct acsi_error {
        unsigned char   code;
        const char              *text;
} atari_acsi_errors[] = {
        { 0x00, "No error (??)" },
        { 0x01, "No index pulses" },
        { 0x02, "Seek not complete" },
        { 0x03, "Write fault" },
        { 0x04, "Drive not ready" },
        { 0x06, "No Track 00 signal" },
        { 0x10, "ECC error in ID field" },
        { 0x11, "Uncorrectable data error" },
        { 0x12, "ID field address mark not found" },
        { 0x13, "Data field address mark not found" },
        { 0x14, "Record not found" },
        { 0x15, "Seek error" },
        { 0x18, "Data check in no retry mode" },
        { 0x19, "ECC error during verify" },
        { 0x1a, "Access to bad block" },
        { 0x1c, "Unformatted or bad format" },
        { 0x20, "Invalid command" },
        { 0x21, "Invalid block address" },
        { 0x23, "Volume overflow" },
        { 0x24, "Invalid argument" },
        { 0x25, "Invalid drive number" },
        { 0x26, "Byte zero parity check" },
        { 0x28, "Cartride changed" },
        { 0x2c, "Error count overflow" },
        { 0x30, "Controller selftest failed" }
},

        scsi_acsi_errors[] = {
        { 0x00, "No error (??)" },
        { 0x01, "Recovered error" },
        { 0x02, "Drive not ready" },
        { 0x03, "Uncorrectable medium error" },
        { 0x04, "Hardware error" },
        { 0x05, "Illegal request" },
        { 0x06, "Unit attention (Reset or cartridge changed)" },
        { 0x07, "Data protection" },
        { 0x08, "Blank check" },
        { 0x0b, "Aborted Command" },
        { 0x0d, "Volume overflow" }
};



/***************************** Prototypes *****************************/

static int acsicmd_dma( const char *cmd, char *buffer, int blocks, int
                        rwflag, int enable);
static int acsi_reqsense( char *buffer, int targ, int lun);
static void acsi_print_error( const unsigned char *errblk, int dev );
static void acsi_interrupt (int irq, void *data, struct pt_regs *fp);
static void unexpected_acsi_interrupt( void );
static void bad_rw_intr( void );
static void read_intr( void );
static void write_intr( void);
static void acsi_times_out( unsigned long dummy );
static void copy_to_acsibuffer( void );
static void copy_from_acsibuffer( void );
static void do_end_requests( void );
static void do_acsi_request( request_queue_t * );
static void redo_acsi_request( void );
static int acsi_ioctl( struct inode *inode, struct file *file, unsigned int
                       cmd, unsigned long arg );
static int acsi_open( struct inode * inode, struct file * filp );
static int acsi_release( struct inode * inode, struct file * file );
static void acsi_prevent_removal( int target, int flag );
static int acsi_change_blk_size( int target, int lun);
static int acsi_mode_sense( int target, int lun, SENSE_DATA *sd );
static void acsi_geninit(void);
static int revalidate_acsidisk( int dev, int maxusage );
static int acsi_revalidate (dev_t);

/************************* End of Prototypes **************************/


struct timer_list acsi_timer = {
    function:   acsi_times_out
};


#ifdef CONFIG_ATARI_SLM

extern int attach_slm( int target, int lun );
extern int slm_init( void );

#endif



/***********************************************************************
 *
 *   ACSI primitives
 *
 **********************************************************************/


/*
 * The following two functions wait for _IRQ to become Low or High,
 * resp., with a timeout. The 'timeout' parameter is in jiffies
 * (10ms).
 * If the functions are called with timer interrupts on (int level <
 * 6), the timeout is based on the 'jiffies' variable to provide exact
 * timeouts for device probing etc.
 * If interrupts are disabled, the number of tries is based on the
 * 'loops_per_jiffy' variable. A rough estimation is sufficient here...
 */

#define INT_LEVEL                                                                                                       \
        ({      unsigned __sr;                                                                                          \
                __asm__ __volatile__ ( "movew   %/sr,%0" : "=dm" (__sr) );      \
                (__sr >> 8) & 7;                                                                                        \
        })

int acsi_wait_for_IRQ( unsigned timeout )

{
        if (INT_LEVEL < 6) {
                unsigned long maxjif = jiffies + timeout;
                while (time_before(jiffies, maxjif))
                        if (!(mfp.par_dt_reg & 0x20)) return( 1 );
        }
        else {
                long tries = loops_per_jiffy / 8 * timeout;
                while( --tries >= 0 )
                        if (!(mfp.par_dt_reg & 0x20)) return( 1 );
        }               
        return( 0 ); /* timeout! */
}


int acsi_wait_for_noIRQ( unsigned timeout )

{
        if (INT_LEVEL < 6) {
                unsigned long maxjif = jiffies + timeout;
                while (time_before(jiffies, maxjif))
                        if (mfp.par_dt_reg & 0x20) return( 1 );
        }
        else {
                long tries = loops_per_jiffy * timeout / 8;
                while( tries-- >= 0 )
                        if (mfp.par_dt_reg & 0x20) return( 1 );
        }               
        return( 0 ); /* timeout! */
}

static struct timeval start_time;

void
acsi_delay_start(void)
{
        do_gettimeofday(&start_time);
}

/* wait from acsi_delay_start to now usec (<1E6) usec */

void
acsi_delay_end(long usec)
{
        struct timeval end_time;
        long deltau,deltas;
        do_gettimeofday(&end_time);
        deltau=end_time.tv_usec - start_time.tv_usec;
        deltas=end_time.tv_sec - start_time.tv_sec;
        if (deltas > 1 || deltas < 0)
                return;
        if (deltas > 0)
                deltau += 1000*1000;
        if (deltau >= usec)
                return;
        udelay(usec-deltau);
}

/* acsicmd_dma() sends an ACSI command and sets up the DMA to transfer
 * 'blocks' blocks of 512 bytes from/to 'buffer'.
 * Because the _IRQ signal is used for handshaking the command bytes,
 * the ACSI interrupt has to be disabled in this function. If the end
 * of the operation should be signalled by a real interrupt, it has to be
 * reenabled afterwards.
 */

static int acsicmd_dma( const char *cmd, char *buffer, int blocks, int rwflag, int enable)

{       unsigned long   flags, paddr;
        int                             i;

#ifdef NO_WRITE
        if (rwflag || *cmd == 0x0a) {
                printk( "ACSI: Write commands disabled!\n" );
                return( 0 );
        }
#endif
        
        rwflag = rwflag ? 0x100 : 0;
        paddr = virt_to_phys( buffer );

        acsi_delay_end(COMMAND_DELAY);
        DISABLE_IRQ();

        save_flags(flags);  
        cli();
        /* Low on A1 */
        dma_wd.dma_mode_status = 0x88 | rwflag;
        MFPDELAY();

        /* set DMA address */
        dma_wd.dma_lo = (unsigned char)paddr;
        paddr >>= 8;
        MFPDELAY();
        dma_wd.dma_md = (unsigned char)paddr;
        paddr >>= 8;
        MFPDELAY();
        if (ATARIHW_PRESENT(EXTD_DMA))
                st_dma_ext_dmahi = (unsigned short)paddr;
        else
                dma_wd.dma_hi = (unsigned char)paddr;
        MFPDELAY();
        restore_flags(flags);

        /* send the command bytes except the last */
        for( i = 0; i < 5; ++i ) {
                DMA_LONG_WRITE( *cmd++, 0x8a | rwflag );
                udelay(20);
                if (!acsi_wait_for_IRQ( HZ/2 )) return( 0 ); /* timeout */
        }

        /* Clear FIFO and switch DMA to correct direction */  
        dma_wd.dma_mode_status = 0x92 | (rwflag ^ 0x100);  
        MFPDELAY();
        dma_wd.dma_mode_status = 0x92 | rwflag;
        MFPDELAY();

        /* How many sectors for DMA */
        dma_wd.fdc_acces_seccount = blocks;
        MFPDELAY();
        
        /* send last command byte */
        dma_wd.dma_mode_status = 0x8a | rwflag;
        MFPDELAY();
        DMA_LONG_WRITE( *cmd++, 0x0a | rwflag );
        if (enable)
                ENABLE_IRQ();
        udelay(80);

        return( 1 );
}


/*
 * acsicmd_nodma() sends an ACSI command that requires no DMA.
 */

int acsicmd_nodma( const char *cmd, int enable)

{       int     i;

        acsi_delay_end(COMMAND_DELAY);
        DISABLE_IRQ();

        /* send first command byte */
        dma_wd.dma_mode_status = 0x88;
        MFPDELAY();
        DMA_LONG_WRITE( *cmd++, 0x8a );
        udelay(20);
        if (!acsi_wait_for_IRQ( HZ/2 )) return( 0 ); /* timeout */

        /* send the intermediate command bytes */
        for( i = 0; i < 4; ++i ) {
                DMA_LONG_WRITE( *cmd++, 0x8a );
                udelay(20);
                if (!acsi_wait_for_IRQ( HZ/2 )) return( 0 ); /* timeout */
        }

        /* send last command byte */
        DMA_LONG_WRITE( *cmd++, 0x0a );
        if (enable)
                ENABLE_IRQ();
        udelay(80);
        
        return( 1 );
        /* Note that the ACSI interrupt is still disabled after this
         * function. If you want to get the IRQ delivered, enable it manually!
         */
}


static int acsi_reqsense( char *buffer, int targ, int lun)

{
        CMDSET_TARG_LUN( reqsense_cmd, targ, lun);
        if (!acsicmd_dma( reqsense_cmd, buffer, 1, 0, 0 )) return( 0 );
        if (!acsi_wait_for_IRQ( 10 )) return( 0 );
        acsi_getstatus();
        if (!acsicmd_nodma( reqsense_cmd, 0 )) return( 0 );
        if (!acsi_wait_for_IRQ( 10 )) return( 0 );
        acsi_getstatus();
        if (!acsicmd_nodma( reqsense_cmd, 0 )) return( 0 );
        if (!acsi_wait_for_IRQ( 10 )) return( 0 );
        acsi_getstatus();
        if (!acsicmd_nodma( reqsense_cmd, 0 )) return( 0 );
        if (!acsi_wait_for_IRQ( 10 )) return( 0 );
        acsi_getstatus();
        dma_cache_maintenance( virt_to_phys(buffer), 16, 0 );
        
        return( 1 );
}       


/*
 * ACSI status phase: get the status byte from the bus
 *
 * I've seen several times that a 0xff status is read, propably due to
 * a timing error. In this case, the procedure is repeated after the
 * next _IRQ edge.
 */

int acsi_getstatus( void )

{       int     status;

        DISABLE_IRQ();
        for(;;) {
                if (!acsi_wait_for_IRQ( 100 )) {
                        acsi_delay_start();
                        return( -1 );
                }
                dma_wd.dma_mode_status = 0x8a;
                MFPDELAY();
                status = dma_wd.fdc_acces_seccount;
                if (status != 0xff) break;
#ifdef DEBUG
                printk("ACSI: skipping 0xff status byte\n" );
#endif
                udelay(40);
                acsi_wait_for_noIRQ( 20 );
        }
        dma_wd.dma_mode_status = 0x80;
        udelay(40);
        acsi_wait_for_noIRQ( 20 );

        acsi_delay_start();
        return( status & 0x1f ); /* mask of the device# */
}


#if (defined(CONFIG_ATARI_SLM) || defined(CONFIG_ATARI_SLM_MODULE))

/* Receive data in an extended status phase. Needed by SLM printer. */

int acsi_extstatus( char *buffer, int cnt )

{       int     status;

        DISABLE_IRQ();
        udelay(80);
        while( cnt-- > 0 ) {
                if (!acsi_wait_for_IRQ( 40 )) return( 0 );
                dma_wd.dma_mode_status = 0x8a;
                MFPDELAY();
                status = dma_wd.fdc_acces_seccount;
                MFPDELAY();
                *buffer++ = status & 0xff;
                udelay(40);
        }
        return( 1 );
}


/* Finish an extended status phase */

void acsi_end_extstatus( void )

{
        dma_wd.dma_mode_status = 0x80;
        udelay(40);
        acsi_wait_for_noIRQ( 20 );
        acsi_delay_start();
}


/* Send data in an extended command phase */

int acsi_extcmd( unsigned char *buffer, int cnt )

{
        while( cnt-- > 0 ) {
                DMA_LONG_WRITE( *buffer++, 0x8a );
                udelay(20);
                if (!acsi_wait_for_IRQ( HZ/2 )) return( 0 ); /* timeout */
        }
        return( 1 );
}

#endif


static void acsi_print_error( const unsigned char *errblk, int dev  )

{       int atari_err, i, errcode;
        struct acsi_error *arr;

        atari_err = acsi_info[dev].old_atari_disk;
        if (atari_err)
                errcode = errblk[0] & 0x7f;
        else
                if ((errblk[0] & 0x70) == 0x70)
                        errcode = errblk[2] & 0x0f;
                else
                        errcode = errblk[0] & 0x0f;
        
        printk( KERN_ERR "ACSI error 0x%02x", errcode );

        if (errblk[0] & 0x80)
                printk( " for sector %d",
                                ((errblk[1] & 0x1f) << 16) |
                                (errblk[2] << 8) | errblk[0] );

        arr = atari_err ? atari_acsi_errors : scsi_acsi_errors;
        i = atari_err ? sizeof(atari_acsi_errors)/sizeof(*atari_acsi_errors) :
                            sizeof(scsi_acsi_errors)/sizeof(*scsi_acsi_errors);
        
        for( --i; i >= 0; --i )
                if (arr[i].code == errcode) break;
        if (i >= 0)
                printk( ": %s\n", arr[i].text );
}

/*******************************************************************
 *
 * ACSI interrupt routine
 *   Test, if this is a ACSI interrupt and call the irq handler
 *   Otherwise ignore this interrupt.
 *
 *******************************************************************/

static void acsi_interrupt(int irq, void *data, struct pt_regs *fp )

{       void (*acsi_irq_handler)(void) = DEVICE_INTR;

        DEVICE_INTR = NULL;
        CLEAR_TIMER();

        if (!acsi_irq_handler)
                acsi_irq_handler = unexpected_acsi_interrupt;
        acsi_irq_handler();
}


/******************************************************************
 *
 * The Interrupt handlers
 *
 *******************************************************************/


static void unexpected_acsi_interrupt( void )

{
        printk( KERN_WARNING "Unexpected ACSI interrupt\n" );
}


/* This function is called in case of errors. Because we cannot reset
 * the ACSI bus or a single device, there is no other choice than
 * retrying several times :-(
 */

static void bad_rw_intr( void )

{
        if (QUEUE_EMPTY)
                return;

        if (++CURRENT->errors >= MAX_ERRORS)
                end_request(0);
        /* Otherwise just retry */
}


static void read_intr( void )

{       int             status;
        
        status = acsi_getstatus();
        if (status != 0) {
                int dev = DEVICE_NR(MINOR(CURRENT->rq_dev));
                printk( KERN_ERR "ad%c: ", dev+'a' );
                if (!acsi_reqsense( acsi_buffer, acsi_info[dev].target, 
                                        acsi_info[dev].lun))
                        printk( "ACSI error and REQUEST SENSE failed (status=0x%02x)\n", status );
                else {
                        acsi_print_error( acsi_buffer, dev );
                        if (CARTRCH_STAT( dev, acsi_buffer ))
                                acsi_info[dev].changed = 1;
                }
                ENABLE_IRQ();
                bad_rw_intr();
                redo_acsi_request();
                return;
        }

        dma_cache_maintenance( virt_to_phys(CurrentBuffer), CurrentNSect*512, 0 );
        if (CurrentBuffer == acsi_buffer)
                copy_from_acsibuffer();

        do_end_requests();
        redo_acsi_request();
}


static void write_intr(void)

{       int     status;

        status = acsi_getstatus();
        if (status != 0) {
                int     dev = DEVICE_NR(MINOR(CURRENT->rq_dev));
                printk( KERN_ERR "ad%c: ", dev+'a' );
                if (!acsi_reqsense( acsi_buffer, acsi_info[dev].target,
                                        acsi_info[dev].lun))
                        printk( "ACSI error and REQUEST SENSE failed (status=0x%02x)\n", status );
                else {
                        acsi_print_error( acsi_buffer, dev );
                        if (CARTRCH_STAT( dev, acsi_buffer ))
                                acsi_info[dev].changed = 1;
                }
                bad_rw_intr();
                redo_acsi_request();
                return;
        }

        do_end_requests();
        redo_acsi_request();
}


static void acsi_times_out( unsigned long dummy )

{
        DISABLE_IRQ();
        if (!DEVICE_INTR) return;

        DEVICE_INTR = NULL;
        printk( KERN_ERR "ACSI timeout\n" );
        if (QUEUE_EMPTY) return;
        if (++CURRENT->errors >= MAX_ERRORS) {
#ifdef DEBUG
                printk( KERN_ERR "ACSI: too many errors.\n" );
#endif
                end_request(0);
        }

        redo_acsi_request();
}



/***********************************************************************
 *
 *  Scatter-gather utility functions
 *
 ***********************************************************************/


static void copy_to_acsibuffer( void )

{       int                                     i;
        char                            *src, *dst;
        struct buffer_head      *bh;
        
        src = CURRENT->buffer;
        dst = acsi_buffer;
        bh = CURRENT->bh;

        if (!bh)
                memcpy( dst, src, CurrentNSect*512 );
        else
                for( i = 0; i < CurrentNReq; ++i ) {
                        memcpy( dst, src, bh->b_size );
                        dst += bh->b_size;
                        if ((bh = bh->b_reqnext))
                                src = bh->b_data;
                }
}


static void copy_from_acsibuffer( void )

{       int                                     i;
        char                            *src, *dst;
        struct buffer_head      *bh;
        
        dst = CURRENT->buffer;
        src = acsi_buffer;
        bh = CURRENT->bh;

        if (!bh)
                memcpy( dst, src, CurrentNSect*512 );
        else
                for( i = 0; i < CurrentNReq; ++i ) {
                        memcpy( dst, src, bh->b_size );
                        src += bh->b_size;
                        if ((bh = bh->b_reqnext))
                                dst = bh->b_data;
                }
}


static void do_end_requests( void )

{       int             i, n;

        if (!CURRENT->bh) {
                CURRENT->nr_sectors -= CurrentNSect;
                CURRENT->current_nr_sectors -= CurrentNSect;
                CURRENT->sector += CurrentNSect;
                if (CURRENT->nr_sectors == 0)
                        end_request(1);
        }
        else {
                for( i = 0; i < CurrentNReq; ++i ) {
                        n = CURRENT->bh->b_size >> 9;
                        CURRENT->nr_sectors -= n;
                        CURRENT->current_nr_sectors -= n;
                        CURRENT->sector += n;
                        end_request(1);
                }
        }
}




/***********************************************************************
 *
 *  do_acsi_request and friends
 *
 ***********************************************************************/

static void do_acsi_request( request_queue_t * q )

{
        stdma_lock( acsi_interrupt, NULL );
        redo_acsi_request();
}


static void redo_acsi_request( void )

{       unsigned                        block, dev, target, lun, nsect;
        char                            *buffer;
        unsigned long           pbuffer;
        struct buffer_head      *bh;
        
        if (!QUEUE_EMPTY && CURRENT->rq_status == RQ_INACTIVE) {
                if (!DEVICE_INTR) {
                        ENABLE_IRQ();
                        stdma_release();
                }
                return;
        }

        if (DEVICE_INTR)
                return;

  repeat:
        CLEAR_TIMER();
        /* Another check here: An interrupt or timer event could have
         * happened since the last check!
         */
        if (!QUEUE_EMPTY && CURRENT->rq_status == RQ_INACTIVE) {
                if (!DEVICE_INTR) {
                        ENABLE_IRQ();
                        stdma_release();
                }
                return;
        }
        if (DEVICE_INTR)
                return;

        if (QUEUE_EMPTY) {
                CLEAR_INTR;
                ENABLE_IRQ();
                stdma_release();
                return;
        }
        
        if (MAJOR(CURRENT->rq_dev) != MAJOR_NR)
                panic(DEVICE_NAME ": request list destroyed");
        if (CURRENT->bh) {
                if (!CURRENT->bh && !buffer_locked(CURRENT->bh))
                        panic(DEVICE_NAME ": block not locked");
        }

        dev = MINOR(CURRENT->rq_dev);
        block = CURRENT->sector;
        if (DEVICE_NR(dev) >= NDevices ||
                block+CURRENT->nr_sectors >= acsi_part[dev].nr_sects) {
#ifdef DEBUG

                printk( "ad%c: attempted access for blocks %d...%ld past end of device at block %ld.\n",
                       DEVICE_NR(dev)+'a',
                       block, block + CURRENT->nr_sectors - 1,
                       acsi_part[dev].nr_sects);
#endif
                end_request(0);
                goto repeat;
        }
        if (acsi_info[DEVICE_NR(dev)].changed) {
                printk( KERN_NOTICE "ad%c: request denied because cartridge has "
                                "been changed.\n", DEVICE_NR(dev)+'a' );
                end_request(0);
                goto repeat;
        }
        
        block += acsi_part[dev].start_sect;
        target = acsi_info[DEVICE_NR(dev)].target;
        lun    = acsi_info[DEVICE_NR(dev)].lun;

        /* Find out how many sectors should be transferred from/to
         * consecutive buffers and thus can be done with a single command.
         */
        buffer      = CURRENT->buffer;
        pbuffer     = virt_to_phys(buffer);
        nsect       = CURRENT->current_nr_sectors;
        CurrentNReq = 1;

        if ((bh = CURRENT->bh) && bh != CURRENT->bhtail) {
                if (!STRAM_ADDR(pbuffer)) {
                        /* If transfer is done via the ACSI buffer anyway, we can
                         * assemble as much bh's as fit in the buffer.
                         */
                        while( (bh = bh->b_reqnext) ) {
                                if (nsect + (bh->b_size>>9) > ACSI_BUFFER_SECTORS) break;
                                nsect += bh->b_size >> 9;
                                ++CurrentNReq;
                                if (bh == CURRENT->bhtail) break;
                        }
                        buffer = acsi_buffer;
                        pbuffer = phys_acsi_buffer;
                }
                else {
                        unsigned long pendadr, pnewadr;
                        pendadr = pbuffer + nsect*512;
                        while( (bh = bh->b_reqnext) ) {
                                pnewadr = virt_to_phys(bh->b_data);
                                if (!STRAM_ADDR(pnewadr) || pendadr != pnewadr) break;
                                nsect += bh->b_size >> 9;
                                pendadr = pnewadr + bh->b_size;
                                ++CurrentNReq;
                                if (bh == CURRENT->bhtail) break;
                        }
                }
        }
        else {
                if (!STRAM_ADDR(pbuffer)) {
                        buffer = acsi_buffer;
                        pbuffer = phys_acsi_buffer;
                        if (nsect > ACSI_BUFFER_SECTORS)
                                nsect = ACSI_BUFFER_SECTORS;
                }
        }
        CurrentBuffer = buffer;
        CurrentNSect  = nsect;
        
        if (CURRENT->cmd == WRITE) {
                CMDSET_TARG_LUN( write_cmd, target, lun );
                CMDSET_BLOCK( write_cmd, block );
                CMDSET_LEN( write_cmd, nsect );
                if (buffer == acsi_buffer)
                        copy_to_acsibuffer();
                dma_cache_maintenance( pbuffer, nsect*512, 1 );
                SET_INTR(write_intr);
                if (!acsicmd_dma( write_cmd, buffer, nsect, 1, 1)) {
                        CLEAR_INTR;
                        printk( KERN_ERR "ACSI (write): Timeout in command block\n" );
                        bad_rw_intr();
                        goto repeat;
                }
                SET_TIMER();
                return;
        }
        if (CURRENT->cmd == READ) {
                CMDSET_TARG_LUN( read_cmd, target, lun );
                CMDSET_BLOCK( read_cmd, block );
                CMDSET_LEN( read_cmd, nsect );
                SET_INTR(read_intr);
                if (!acsicmd_dma( read_cmd, buffer, nsect, 0, 1)) {
                        CLEAR_INTR;
                        printk( KERN_ERR "ACSI (read): Timeout in command block\n" );
                        bad_rw_intr();
                        goto repeat;
                }
                SET_TIMER();
                return;
        }
        panic("unknown ACSI command");
}



/***********************************************************************
 *
 *  Misc functions: ioctl, open, release, check_change, ...
 *
 ***********************************************************************/


static int acsi_ioctl( struct inode *inode, struct file *file,
                                           unsigned int cmd, unsigned long arg )
{       int dev;

        if (!inode)
                return -EINVAL;
        dev = DEVICE_NR(MINOR(inode->i_rdev));
        if (dev >= NDevices)
                return -EINVAL;
        switch (cmd) {
          case HDIO_GETGEO:
                /* HDIO_GETGEO is supported more for getting the partition's
                 * start sector... */
          { struct hd_geometry *geo = (struct hd_geometry *)arg;
            /* just fake some geometry here, it's nonsense anyway; to make it
                 * easy, use Adaptec's usual 64/32 mapping */
            put_user( 64, &geo->heads );
            put_user( 32, &geo->sectors );
            put_user( acsi_info[dev].size >> 11, &geo->cylinders );
                put_user( acsi_part[MINOR(inode->i_rdev)].start_sect, &geo->start );
                return 0;
          }
                
          case SCSI_IOCTL_GET_IDLUN:
                /* SCSI compatible GET_IDLUN call to get target's ID and LUN number */
                put_user( acsi_info[dev].target | (acsi_info[dev].lun << 8),
                                  &((Scsi_Idlun *) arg)->dev_id );
                put_user( 0, &((Scsi_Idlun *) arg)->host_unique_id );
                return 0;
                
          case BLKGETSIZE:
          case BLKGETSIZE64:
          case BLKROSET:
          case BLKROGET:
          case BLKFLSBUF:
          case BLKPG:
                return blk_ioctl(inode->i_rdev, cmd, arg);

          case BLKRRPART: /* Re-read partition tables */
                if (!capable(CAP_SYS_ADMIN)) 
                        return -EACCES;
                return revalidate_acsidisk(inode->i_rdev, 1);

          default:
                return -EINVAL;
        }
}


/*
 * Open a device, check for read-only and lock the medium if it is
 * removable.
 *
 * Changes by Martin Rogge, 9th Aug 1995:
 * Check whether check_disk_change (and therefore revalidate_acsidisk)
 * was successful. They fail when there is no medium in the drive.
 *
 * The problem of media being changed during an operation can be 
 * ignored because of the prevent_removal code.
 *
 * Added check for the validity of the device number.
 *
 */

static int acsi_open( struct inode * inode, struct file * filp )
{
        int  device;
        struct acsi_info_struct *aip;

        device = DEVICE_NR(MINOR(inode->i_rdev));
        if (device >= NDevices)
                return -ENXIO;
        aip = &acsi_info[device];
        while (busy[device])
                sleep_on(&busy_wait);

        if (access_count[device] == 0 && aip->removable) {
#if 0
                aip->changed = 1;       /* safety first */
#endif
                check_disk_change( inode->i_rdev );
                if (aip->changed)       /* revalidate was not successful (no medium) */
                        return -ENXIO;
                acsi_prevent_removal(device, 1);
        }
        access_count[device]++;

        if (filp && filp->f_mode) {
                check_disk_change( inode->i_rdev );
                if (filp->f_mode & 2) {
                        if (aip->read_only) {
                                acsi_release( inode, filp );
                                return -EROFS;
                        }
                }
        }

        return 0;
}

/*
 * Releasing a block device means we sync() it, so that it can safely
 * be forgotten about...
 */

static int acsi_release( struct inode * inode, struct file * file )
{
        int device = DEVICE_NR(MINOR(inode->i_rdev));
        if (--access_count[device] == 0 && acsi_info[device].removable)
                acsi_prevent_removal(device, 0);
        return( 0 );
}

/*
 * Prevent or allow a media change for removable devices.
 */

static void acsi_prevent_removal(int device, int flag)
{
        stdma_lock( NULL, NULL );
        
        CMDSET_TARG_LUN(pa_med_rem_cmd, acsi_info[device].target,
                        acsi_info[device].lun);
        CMDSET_LEN( pa_med_rem_cmd, flag );
        
        if (acsicmd_nodma(pa_med_rem_cmd, 0) && acsi_wait_for_IRQ(3*HZ))
                acsi_getstatus();
        /* Do not report errors -- some devices may not know this command. */

        ENABLE_IRQ();
        stdma_release();
}

static int acsi_media_change (dev_t dev)
{
        int device = DEVICE_NR(MINOR(dev));
        struct acsi_info_struct *aip;

        aip = &acsi_info[device];
        if (!aip->removable) 
                return 0;

        if (aip->changed)
                /* We can be sure that the medium has been changed -- REQUEST
                 * SENSE has reported this earlier.
                 */
                return 1;

        /* If the flag isn't set, make a test by reading block 0.
         * If errors happen, it seems to be better to say "changed"...
         */
        stdma_lock( NULL, NULL );
        CMDSET_TARG_LUN(read_cmd, aip->target, aip->lun);
        CMDSET_BLOCK( read_cmd, 0 );
        CMDSET_LEN( read_cmd, 1 );
        if (acsicmd_dma(read_cmd, acsi_buffer, 1, 0, 0) &&
            acsi_wait_for_IRQ(3*HZ)) {
                if (acsi_getstatus()) {
                        if (acsi_reqsense(acsi_buffer, aip->target, aip->lun)) {
                                if (CARTRCH_STAT(device, acsi_buffer))
                                        aip->changed = 1;
                        }
                        else {
                                printk( KERN_ERR "ad%c: REQUEST SENSE failed in test for "
                                       "medium change; assuming a change\n", device + 'a' );
                                aip->changed = 1;
                        }
                }
        }
        else {
                printk( KERN_ERR "ad%c: Test for medium changed timed out; "
                                "assuming a change\n", device + 'a');
                aip->changed = 1;
        }
        ENABLE_IRQ();
        stdma_release();

        /* Now, after reading a block, the changed status is surely valid. */
        return aip->changed;
}


static int acsi_change_blk_size( int target, int lun)

{       int i;

        for (i=0; i<12; i++)
                acsi_buffer[i] = 0;

        acsi_buffer[3] = 8;
        acsi_buffer[10] = 2;
        CMDSET_TARG_LUN( modeselect_cmd, target, lun);

        if (!acsicmd_dma( modeselect_cmd, acsi_buffer, 1,1,0) ||
                !acsi_wait_for_IRQ( 3*HZ ) ||
                acsi_getstatus() != 0 ) {
                return(0);
        }
        return(1);
}


static int acsi_mode_sense( int target, int lun, SENSE_DATA *sd )

{
        int page;

        CMDSET_TARG_LUN( modesense_cmd, target, lun );
        for (page=0; page<4; page++) {
                modesense_cmd[2] = page;
                if (!acsicmd_dma( modesense_cmd, acsi_buffer, 1, 0, 0 ) ||
                    !acsi_wait_for_IRQ( 3*HZ ) ||
                    acsi_getstatus())
                        continue;

                /* read twice to jump over the second 16-byte border! */
                udelay(300);
                if (acsi_wait_for_noIRQ( 20 ) &&
                    acsicmd_nodma( modesense_cmd, 0 ) &&
                    acsi_wait_for_IRQ( 3*HZ ) &&
                    acsi_getstatus() == 0)
                        break;
        }
        if (page == 4) {
                return(0);
        }

        dma_cache_maintenance( phys_acsi_buffer, sizeof(SENSE_DATA), 0 );
        *sd = *(SENSE_DATA *)acsi_buffer;

        /* Validity check, depending on type of data */
        
        switch( SENSE_TYPE(*sd) ) {

          case SENSE_TYPE_ATARI:
                if (CAPACITY(*sd) == 0)
                        goto invalid_sense;
                break;

          case SENSE_TYPE_SCSI:
                if (sd->scsi.descriptor_size != 8)
                        goto invalid_sense;
                break;

          case SENSE_TYPE_UNKNOWN:

                printk( KERN_ERR "ACSI target %d, lun %d: Cannot interpret "
                                "sense data\n", target, lun ); 
                
          invalid_sense:

#ifdef DEBUG
                {       int i;
                printk( "Mode sense data for ACSI target %d, lun %d seem not valid:",
                                target, lun );
                for( i = 0; i < sizeof(SENSE_DATA); ++i )
                        printk( "%02x ", (unsigned char)acsi_buffer[i] );
                printk( "\n" );
                }
#endif
                return( 0 );
        }
                
        return( 1 );
}



/*******************************************************************
 *
 *  Initialization
 *
 ********************************************************************/


extern struct block_device_operations acsi_fops;

static struct gendisk acsi_gendisk = {
        major:          MAJOR_NR,
        major_name:     "ad",
        minor_shift:    4,
        max_p:          1 << 4,
        part:           acsi_part,
        sizes:          acsi_sizes,
        real_devices:   (void *)acsi_info,
        fops:           &acsi_fops,
};
        
#define MAX_SCSI_DEVICE_CODE 10

static const char *const scsi_device_types[MAX_SCSI_DEVICE_CODE] =
{
 "Direct-Access    ",
 "Sequential-Access",
 "Printer          ",
 "Processor        ",
 "WORM             ",
 "CD-ROM           ",
 "Scanner          ",
 "Optical Device   ",
 "Medium Changer   ",
 "Communications   "
};

static void print_inquiry(unsigned char *data)
{
        int i;

        printk(KERN_INFO "  Vendor: ");
        for (i = 8; i < 16; i++)
                {
                if (data[i] >= 0x20 && i < data[4] + 5)
                        printk("%c", data[i]);
                else
                        printk(" ");
                }

        printk("  Model: ");
        for (i = 16; i < 32; i++)
                {
                if (data[i] >= 0x20 && i < data[4] + 5)
                        printk("%c", data[i]);
                else
                        printk(" ");
                }

        printk("  Rev: ");
        for (i = 32; i < 36; i++)
                {
                if (data[i] >= 0x20 && i < data[4] + 5)
                        printk("%c", data[i]);
                else
                        printk(" ");
                }

        printk("\n");

        i = data[0] & 0x1f;

        printk(KERN_INFO "  Type:   %s ", (i < MAX_SCSI_DEVICE_CODE
                                                                           ? scsi_device_types[i]
                                                                           : "Unknown          "));
        printk("                 ANSI SCSI revision: %02x", data[2] & 0x07);
        if ((data[2] & 0x07) == 1 && (data[3] & 0x0f) == 1)
          printk(" CCS\n");
        else
          printk("\n");
}


/* 
 * Changes by Martin Rogge, 9th Aug 1995: 
 * acsi_devinit has been taken out of acsi_geninit, because it needs 
 * to be called from revalidate_acsidisk. The result of request sense 
 * is now checked for DRIVE NOT READY.
 *
 * The structure *aip is only valid when acsi_devinit returns 
 * DEV_SUPPORTED. 
 *
 */
        
#define DEV_NONE        0
#define DEV_UNKNOWN     1
#define DEV_SUPPORTED   2
#define DEV_SLM         3

static int acsi_devinit(struct acsi_info_struct *aip)
{
        int status, got_inquiry;
        SENSE_DATA sense;
        unsigned char reqsense, extsense;

        /*****************************************************************/
        /* Do a TEST UNIT READY command to test the presence of a device */
        /*****************************************************************/

        CMDSET_TARG_LUN(tur_cmd, aip->target, aip->lun);
        if (!acsicmd_nodma(tur_cmd, 0)) {
                /* timed out -> no device here */
#ifdef DEBUG_DETECT
                printk("target %d lun %d: timeout\n", aip->target, aip->lun);
#endif
                return DEV_NONE;
        }
                
        /*************************/
        /* Read the ACSI status. */
        /*************************/

        status = acsi_getstatus();
        if (status) {
                if (status == 0x12) {
                        /* The SLM printer should be the only device that
                         * responds with the error code in the status byte. In
                         * correct status bytes, bit 4 is never set.
                         */
                        printk( KERN_INFO "Detected SLM printer at id %d lun %d\n",
                               aip->target, aip->lun);
                        return DEV_SLM;
                }
                /* ignore CHECK CONDITION, since some devices send a
                   UNIT ATTENTION */
                if ((status & 0x1e) != 0x2) {
#ifdef DEBUG_DETECT
                        printk("target %d lun %d: status %d\n",
                               aip->target, aip->lun, status);
#endif
                        return DEV_UNKNOWN;
                }
        }

        /*******************************/
        /* Do a REQUEST SENSE command. */
        /*******************************/

        if (!acsi_reqsense(acsi_buffer, aip->target, aip->lun)) {
                printk( KERN_WARNING "acsi_reqsense failed\n");
                acsi_buffer[0] = 0;
                acsi_buffer[2] = UNIT_ATTENTION;
        }
        reqsense = acsi_buffer[0];
        extsense = acsi_buffer[2] & 0xf;
        if (status) {
                if ((reqsense & 0x70) == 0x70) {        /* extended sense */
                        if (extsense != UNIT_ATTENTION &&
                            extsense != NOT_READY) {
#ifdef DEBUG_DETECT
                                printk("target %d lun %d: extended sense %d\n",
                                       aip->target, aip->lun, extsense);
#endif
                                return DEV_UNKNOWN;
                        }
                }
                else {
                        if (reqsense & 0x7f) {
#ifdef DEBUG_DETECT
                                printk("target %d lun %d: sense %d\n",
                                       aip->target, aip->lun, reqsense);
#endif
                                return DEV_UNKNOWN;
                        }
                }
        }
        else 
                if (reqsense == 0x4) {  /* SH204 Bug workaround */
#ifdef DEBUG_DETECT
                        printk("target %d lun %d status=0 sense=4\n",
                               aip->target, aip->lun);
#endif
                        return DEV_UNKNOWN;
                }

        /***********************************************************/
        /* Do an INQUIRY command to get more infos on this device. */
        /***********************************************************/

        /* Assume default values */
        aip->removable = 1;
        aip->read_only = 0;
        aip->old_atari_disk = 0;
        aip->changed = (extsense == NOT_READY); /* medium inserted? */
        aip->size = DEFAULT_SIZE;
        got_inquiry = 0;
        /* Fake inquiry result for old atari disks */
        memcpy(acsi_buffer, "\000\000\001\000    Adaptec 40xx"
               "                    ", 40);
        CMDSET_TARG_LUN(inquiry_cmd, aip->target, aip->lun);
        if (acsicmd_dma(inquiry_cmd, acsi_buffer, 1, 0, 0) &&
            acsi_getstatus() == 0) {
                acsicmd_nodma(inquiry_cmd, 0);
                acsi_getstatus();
                dma_cache_maintenance( phys_acsi_buffer, 256, 0 );
                got_inquiry = 1;
                aip->removable = !!(acsi_buffer[1] & 0x80);
        }
        if (aip->type == NONE)  /* only at boot time */
                print_inquiry(acsi_buffer);
        switch(acsi_buffer[0]) {
          case TYPE_DISK:
                aip->type = HARDDISK;
                break;
          case TYPE_ROM:
                aip->type = CDROM;
                aip->read_only = 1;
                break;
          default:
                return DEV_UNKNOWN;
        }
        /****************************/
        /* Do a MODE SENSE command. */
        /****************************/

        if (!acsi_mode_sense(aip->target, aip->lun, &sense)) {
                printk( KERN_WARNING "No mode sense data.\n" );
                return DEV_UNKNOWN;
        }
        if ((SECTOR_SIZE(sense) != 512) &&
            ((aip->type != CDROM) ||
             !acsi_change_blk_size(aip->target, aip->lun) ||
             !acsi_mode_sense(aip->target, aip->lun, &sense) ||
             (SECTOR_SIZE(sense) != 512))) {
                printk( KERN_WARNING "Sector size != 512 not supported.\n" );
                return DEV_UNKNOWN;
        }
        /* There are disks out there that claim to have 0 sectors... */
        if (CAPACITY(sense))
                aip->size = CAPACITY(sense);    /* else keep DEFAULT_SIZE */
        if (!got_inquiry && SENSE_TYPE(sense) == SENSE_TYPE_ATARI) {
                /* If INQUIRY failed and the sense data suggest an old
                 * Atari disk (SH20x, Megafile), the disk is not removable
                 */
                aip->removable = 0;
                aip->old_atari_disk = 1;
        }
        
        /******************/
        /* We've done it. */
        /******************/
        
        return DEV_SUPPORTED;
}

EXPORT_SYMBOL(acsi_delay_start);
EXPORT_SYMBOL(acsi_delay_end);
EXPORT_SYMBOL(acsi_wait_for_IRQ);
EXPORT_SYMBOL(acsi_wait_for_noIRQ);
EXPORT_SYMBOL(acsicmd_nodma);
EXPORT_SYMBOL(acsi_getstatus);
EXPORT_SYMBOL(acsi_buffer);
EXPORT_SYMBOL(phys_acsi_buffer);

#ifdef CONFIG_ATARI_SLM_MODULE
void acsi_attach_SLMs( int (*attach_func)( int, int ) );

EXPORT_SYMBOL(acsi_extstatus);
EXPORT_SYMBOL(acsi_end_extstatus);
EXPORT_SYMBOL(acsi_extcmd);
EXPORT_SYMBOL(acsi_attach_SLMs);

/* to remember IDs of SLM devices, SLM module is loaded later
 * (index is target#, contents is lun#, -1 means "no SLM") */
int SLM_devices[8];
#endif

static struct block_device_operations acsi_fops = {
        owner:                  THIS_MODULE,
        open:                   acsi_open,
        release:                acsi_release,
        ioctl:                  acsi_ioctl,
        check_media_change:     acsi_media_change,
        revalidate:             acsi_revalidate,
};

static void acsi_geninit(void)
{
        int i, target, lun;
        struct acsi_info_struct *aip;
#ifdef CONFIG_ATARI_SLM
        int n_slm = 0;
#endif

        printk( KERN_INFO "Probing ACSI devices:\n" );
        NDevices = 0;
#ifdef CONFIG_ATARI_SLM_MODULE
        for( i = 0; i < 8; ++i )
                SLM_devices[i] = -1;
#endif
        stdma_lock(NULL, NULL);

        for (target = 0; target < 8 && NDevices < MAX_DEV; ++target) {
                lun = 0;
                do {
                        aip = &acsi_info[NDevices];
                        aip->type = NONE;
                        aip->target = target;
                        aip->lun = lun;
                        i = acsi_devinit(aip);
                        switch (i) {
                          case DEV_SUPPORTED:
                                printk( KERN_INFO "Detected ");
                                switch (aip->type) {
                                  case HARDDISK:
                                        printk("disk");
                                        break;
                                  case CDROM:
                                        printk("cdrom");
                                        break;
                                  default:
                                }
                                printk(" ad%c at id %d lun %d ",
                                       'a' + NDevices, target, lun);
                                if (aip->removable) 
                                        printk("(removable) ");
                                if (aip->read_only) 
                                        printk("(read-only) ");
                                if (aip->size == DEFAULT_SIZE)
                                        printk(" unkown size, using default ");
                                printk("%ld MByte\n",
                                       (aip->size*512+1024*1024/2)/(1024*1024));
                                NDevices++;
                                break;
                          case DEV_SLM:
#ifdef CONFIG_ATARI_SLM
                                n_slm += attach_slm( target, lun );
                                break;
#endif
#ifdef CONFIG_ATARI_SLM_MODULE
                                SLM_devices[target] = lun;
                                break;
#endif
                                /* neither of the above: fall through to unknown device */
                          case DEV_UNKNOWN:
                                printk( KERN_INFO "Detected unsupported device at "
                                                "id %d lun %d\n", target, lun);
                                break;
                        }
                }
#ifdef CONFIG_ACSI_MULTI_LUN
                while (i != DEV_NONE && ++lun < MAX_LUN);
#else
                while (0);
#endif
        }

        /* reenable interrupt */
        ENABLE_IRQ();
        stdma_release();

#ifndef CONFIG_ATARI_SLM
        printk( KERN_INFO "Found %d ACSI device(s) total.\n", NDevices );
#else
        printk( KERN_INFO "Found %d ACSI device(s) and %d SLM printer(s) total.\n",
                        NDevices, n_slm );
#endif
                                         
        for( i = 0; i < (MAX_DEV << 4); i++ )
                acsi_blocksizes[i] = 1024;
        blksize_size[MAJOR_NR] = acsi_blocksizes;
        for( i = 0; i < NDevices; ++i )
                register_disk(&acsi_gendisk, MKDEV(MAJOR_NR,i<<4),
                                (acsi_info[i].type==HARDDISK)?1<<4:1,
                                &acsi_fops,
                                acsi_info[i].size);
        acsi_gendisk.nr_real = NDevices;
}

#ifdef CONFIG_ATARI_SLM_MODULE
/* call attach_slm() for each device that is a printer; needed for init of SLM
 * driver as a module, since it's not yet present if acsi.c is inited and thus
 * the bus gets scanned. */
void acsi_attach_SLMs( int (*attach_func)( int, int ) )
{
        int i, n = 0;

        for( i = 0; i < 8; ++i )
                if (SLM_devices[i] >= 0)
                        n += (*attach_func)( i, SLM_devices[i] );
        printk( KERN_INFO "Found %d SLM printer(s) total.\n", n );
}
#endif /* CONFIG_ATARI_SLM_MODULE */


int acsi_init( void )

{
        int err = 0;
        if (!MACH_IS_ATARI || !ATARIHW_PRESENT(ACSI))
                return 0;
        if (devfs_register_blkdev( MAJOR_NR, "ad", &acsi_fops )) {
                printk( KERN_ERR "Unable to get major %d for ACSI\n", MAJOR_NR );
                return -EBUSY;
        }
        if (!(acsi_buffer =
                  (char *)atari_stram_alloc(ACSI_BUFFER_SIZE, "acsi"))) {
                printk( KERN_ERR "Unable to get ACSI ST-Ram buffer.\n" );
                devfs_unregister_blkdev( MAJOR_NR, "ad" );
                return -ENOMEM;
        }
        phys_acsi_buffer = virt_to_phys( acsi_buffer );
        STramMask = ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000 : 0xff000000;
        
        blk_init_queue(BLK_DEFAULT_QUEUE(MAJOR_NR), DEVICE_REQUEST);
        read_ahead[MAJOR_NR] = 8;               /* 8 sector (4kB) read-ahead */
        add_gendisk(&acsi_gendisk);

#ifdef CONFIG_ATARI_SLM
        err = slm_init();
#endif
        if (!err)
                acsi_geninit();
        return err;
}


#ifdef MODULE

MODULE_LICENSE("GPL");

int init_module(void)
{
        int err;

        if ((err = acsi_init()))
                return( err );
        printk( KERN_INFO "ACSI driver loaded as module.\n");
        return( 0 );
}

void cleanup_module(void)
{
        del_timer( &acsi_timer );
        blk_cleanup_queue(BLK_DEFAULT_QUEUE(MAJOR_NR));
        atari_stram_free( acsi_buffer );

        if (devfs_unregister_blkdev( MAJOR_NR, "ad" ) != 0)
                printk( KERN_ERR "acsi: cleanup_module failed\n");

        del_gendisk(&acsi_gendisk);
}
#endif

#define DEVICE_BUSY busy[device]
#define USAGE access_count[device]
#define GENDISK_STRUCT acsi_gendisk

/*
 * This routine is called to flush all partitions and partition tables
 * for a changed scsi disk, and then re-read the new partition table.
 * If we are revalidating a disk because of a media change, then we
 * enter with usage == 0.  If we are using an ioctl, we automatically have
 * usage == 1 (we need an open channel to use an ioctl :-), so this
 * is our limit.
 *
 * Changes by Martin Rogge, 9th Aug 1995: 
 * got cd-roms to work by calling acsi_devinit. There are only two problems:
 * First, if there is no medium inserted, the status will remain "changed".
 * That is no problem at all, but our design of three-valued logic (medium
 * changed, medium not changed, no medium inserted).
 * Secondly the check could fail completely and the drive could deliver
 * nonsensical data, which could mess up the acsi_info[] structure. In
 * that case we try to make the entry safe.
 *
 */

static int revalidate_acsidisk( int dev, int maxusage )
{
        int device;
        struct gendisk * gdev;
        int max_p, start, i;
        struct acsi_info_struct *aip;
        
        device = DEVICE_NR(MINOR(dev));
        aip = &acsi_info[device];
        gdev = &GENDISK_STRUCT;

        cli();
        if (DEVICE_BUSY || USAGE > maxusage) {
                sti();
                return -EBUSY;
        };
        DEVICE_BUSY = 1;
        sti();

        max_p = gdev->max_p;
        start = device << gdev->minor_shift;

        for( i = max_p - 1; i >= 0 ; i-- ) {
                if (gdev->part[start + i].nr_sects != 0) {
                        invalidate_device(MKDEV(MAJOR_NR, start + i), 1);
                        gdev->part[start + i].nr_sects = 0;
                }
                gdev->part[start+i].start_sect = 0;
        };

        stdma_lock( NULL, NULL );

        if (acsi_devinit(aip) != DEV_SUPPORTED) {
                printk( KERN_ERR "ACSI: revalidate failed for target %d lun %d\n",
                       aip->target, aip->lun);
                aip->size = 0;
                aip->read_only = 1;
                aip->removable = 1;
                aip->changed = 1; /* next acsi_open will try again... */
        }

        ENABLE_IRQ();
        stdma_release();
        
        grok_partitions(gdev, device, (aip->type==HARDDISK)?1<<4:1, aip->size);

        DEVICE_BUSY = 0;
        wake_up(&busy_wait);
        return 0;
}


static int acsi_revalidate (dev_t dev)
{
  return revalidate_acsidisk (dev, 0);
}