acsi.c

Linux块设备驱动源码

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, struct acsi_info_struct *aip)

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

	atari_err = aip->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 irqreturn_t acsi_interrupt(int irq, void *data, struct pt_regs *fp )

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

	do_acsi = NULL;
	CLEAR_TIMER();

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


/******************************************************************
 *
 * 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 (!CURRENT)
		return;

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


static void read_intr( void )

{	int		status;
	
	status = acsi_getstatus();
	if (status != 0) {
		struct gendisk *disk = CURRENT->rq_disk;
		struct acsi_info_struct *aip = disk->private_data;
		printk(KERN_ERR "%s: ", disk->disk_name);
		if (!acsi_reqsense(acsi_buffer, aip->target, aip->lun))
			printk( "ACSI error and REQUEST SENSE failed (status=0x%02x)\n", status );
		else {
			acsi_print_error(acsi_buffer, aip);
			if (CARTRCH_STAT(aip, acsi_buffer))
				aip->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) {
		struct gendisk *disk = CURRENT->rq_disk;
		struct acsi_info_struct *aip = disk->private_data;
		printk( KERN_ERR "%s: ", disk->disk_name);
		if (!acsi_reqsense( acsi_buffer, aip->target, aip->lun))
			printk( "ACSI error and REQUEST SENSE failed (status=0x%02x)\n", status );
		else {
			acsi_print_error(acsi_buffer, aip);
			if (CARTRCH_STAT(aip, acsi_buffer))
				aip->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 (!do_acsi) return;

	do_acsi = NULL;
	printk( KERN_ERR "ACSI timeout\n" );
	if (!CURRENT)
	    return;
	if (++CURRENT->errors >= MAX_ERRORS) {
#ifdef DEBUG
		printk( KERN_ERR "ACSI: too many errors.\n" );
#endif
		end_request(CURRENT, 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(CURRENT, 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(CURRENT, 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, target, lun, nsect;
	char 				*buffer;
	unsigned long		pbuffer;
	struct buffer_head	*bh;
	struct gendisk *disk;
	struct acsi_info_struct *aip;

  repeat:
	CLEAR_TIMER();

	if (do_acsi)
		return;

	if (!CURRENT) {
		do_acsi = NULL;
		ENABLE_IRQ();
		stdma_release();
		return;
	}

	disk = CURRENT->rq_disk;
	aip = disk->private_data;
	if (CURRENT->bh) {
		if (!CURRENT->bh && !buffer_locked(CURRENT->bh))
			panic("ACSI: block not locked");
	}

	block = CURRENT->sector;
	if (block+CURRENT->nr_sectors >= get_capacity(disk)) {
#ifdef DEBUG
		printk( "%s: attempted access for blocks %d...%ld past end of device at block %ld.\n",
		       disk->disk_name,
		       block, block + CURRENT->nr_sectors - 1,
		       get_capacity(disk));
#endif
		end_request(CURRENT, 0);
		goto repeat;
	}
	if (aip->changed) {
		printk( KERN_NOTICE "%s: request denied because cartridge has "
				"been changed.\n", disk->disk_name);
		end_request(CURRENT, 0);
		goto repeat;
	}
	
	target = aip->target;
	lun    = aip->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 (rq_data_dir(CURRENT) == 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 );
		do_acsi = write_intr;
		if (!acsicmd_dma( write_cmd, buffer, nsect, 1, 1)) {
			do_acsi = NULL;
			printk( KERN_ERR "ACSI (write): Timeout in command block\n" );
			bad_rw_intr();
			goto repeat;
		}
		SET_TIMER();
		return;
	}
	if (rq_data_dir(CURRENT) == READ) {
		CMDSET_TARG_LUN( read_cmd, target, lun );
		CMDSET_BLOCK( read_cmd, block );
		CMDSET_LEN( read_cmd, nsect );
		do_acsi = read_intr;
		if (!acsicmd_dma( read_cmd, buffer, nsect, 0, 1)) {
			do_acsi = NULL;
			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 )
{
	struct gendisk *disk = inode->i_bdev->bd_disk;
	struct acsi_info_struct *aip = disk->private_data;
	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( aip->size >> 11, &geo->cylinders );
		put_user(get_start_sect(inode->i_bdev), &geo->start);
		return 0;
	  }
	  case SCSI_IOCTL_GET_IDLUN:
		/* SCSI compatible GET_IDLUN call to get target's ID and LUN number */
		put_user( aip->target | (aip->lun << 8),
				  &((Scsi_Idlun *) arg)->dev_id );
		put_user( 0, &((Scsi_Idlun *) arg)->host_unique_id );
		return 0;
	  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 )
{
	struct gendisk *disk = inode->i_bdev->bd_disk;
	struct acsi_info_struct *aip = disk->private_data;

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

	if (filp && filp->f_mode) {
		check_disk_change( inode->i_bdev );
		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 )
{
	struct gendisk *disk = inode->i_bdev->bd_disk;
	struct acsi_info_struct *aip = disk->private_data;
	if (--aip->access_count == 0 && aip->removable)
		acsi_prevent_removal(aip, 0);
	return( 0 );
}

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

static void acsi_prevent_removal(struct acsi_info_struct *aip, int flag)
{
	stdma_lock( NULL, NULL );
	
	CMDSET_TARG_LUN(pa_med_rem_cmd, aip->target, aip->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(struct gendisk *disk)
{
	struct acsi_info_struct *aip = disk->private_data;

	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(aip, acsi_buffer))
					aip->changed = 1;
			}
			else {
				printk( KERN_ERR "%s: REQUEST SENSE failed in test for "
				       "medium change; assuming a change\n", disk->disk_name );