scsi_obsolete.c

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/*
 *  scsi_obsolete.c Copyright (C) 1992 Drew Eckhardt
 *         Copyright (C) 1993, 1994, 1995 Eric Youngdale
 *
 *  generic mid-level SCSI driver
 *      Initial versions: Drew Eckhardt
 *      Subsequent revisions: Eric Youngdale
 *
 *  <[e-mail]>
 *
 *  Bug correction thanks go to :
 *      Rik Faith <[e-mail]>
 *      Tommy Thorn <tthorn>
 *      Thomas Wuensche <[e-mail]>
 *
 *  Modified by Eric Youngdale [e-mail] to
 *  add scatter-gather, multiple outstanding request, and other
 *  enhancements.
 *
 *  Native multichannel, wide scsi, /proc/scsi and hot plugging
 *  support added by Michael Neuffer <[e-mail]>
 *
 *  Major improvements to the timeout, abort, and reset processing,
 *  as well as performance modifications for large queue depths by
 *  Leonard N. Zubkoff <[e-mail]>
 *
 *  Improved compatibility with 2.0 behaviour by Manfred Spraul
 *  <[e-mail]>
 */

/*
 *#########################################################################
 *#########################################################################
 *#########################################################################
 *#########################################################################
 *              NOTE - NOTE - NOTE - NOTE - NOTE - NOTE - NOTE
 *
 *#########################################################################
 *#########################################################################
 *#########################################################################
 *#########################################################################
 *
 * This file contains the 'old' scsi error handling.  It is only present
 * while the new error handling code is being debugged, and while the low
 * level drivers are being converted to use the new code.  Once the last
 * driver uses the new code this *ENTIRE* file will be nuked.
 */

#define __NO_VERSION__
#include <linux/module.h>

#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/malloc.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/stat.h>
#include <linux/blk.h>
#include <linux/interrupt.h>
#include <linux/delay.h>

#include <asm/system.h>
#include <asm/irq.h>
#include <asm/dma.h>

#include "scsi.h"
#include "hosts.h"
#include "constants.h"

#undef USE_STATIC_SCSI_MEMORY

/*
   static const char RCSid[] = "$Header: /mnt/ide/home/eric/CVSROOT/linux/drivers/scsi/scsi_obsolete.c,v 1.1 1997/05/18 23:27:21 eric Exp $";
 */


#define INTERNAL_ERROR (panic ("Internal error in file %s, line %d.\n", __FILE__, __LINE__))


static int scsi_abort(Scsi_Cmnd *, int code);
static int scsi_reset(Scsi_Cmnd *, unsigned int);

extern void scsi_old_done(Scsi_Cmnd * SCpnt);
int update_timeout(Scsi_Cmnd *, int);
extern void scsi_old_times_out(Scsi_Cmnd * SCpnt);

extern int scsi_dispatch_cmd(Scsi_Cmnd * SCpnt);

#define SCSI_BLOCK(HOST) (HOST->can_queue && HOST->host_busy >= HOST->can_queue)

static unsigned char generic_sense[6] =
{REQUEST_SENSE, 0, 0, 0, 255, 0};

/*
 *  This is the number  of clock ticks we should wait before we time out
 *  and abort the command.  This is for  where the scsi.c module generates
 *  the command, not where it originates from a higher level, in which
 *  case the timeout is specified there.
 *
 *  ABORT_TIMEOUT and RESET_TIMEOUT are the timeouts for RESET and ABORT
 *  respectively.
 */

#ifdef DEBUG_TIMEOUT
static void scsi_dump_status(void);
#endif


#ifdef DEBUG
#define SCSI_TIMEOUT (5*HZ)
#else
#define SCSI_TIMEOUT (2*HZ)
#endif

#ifdef DEBUG
#define SENSE_TIMEOUT SCSI_TIMEOUT
#define ABORT_TIMEOUT SCSI_TIMEOUT
#define RESET_TIMEOUT SCSI_TIMEOUT
#else
#define SENSE_TIMEOUT (5*HZ/10)
#define RESET_TIMEOUT (5*HZ/10)
#define ABORT_TIMEOUT (5*HZ/10)
#endif


/* Do not call reset on error if we just did a reset within 15 sec. */
#define MIN_RESET_PERIOD (15*HZ)



/*
 *  Flag bits for the internal_timeout array
 */
#define IN_ABORT  1
#define IN_RESET  2
#define IN_RESET2 4
#define IN_RESET3 8

/*
 * This is our time out function, called when the timer expires for a
 * given host adapter.  It will attempt to abort the currently executing
 * command, that failing perform a kernel panic.
 */

void scsi_old_times_out(Scsi_Cmnd * SCpnt)
{
	unsigned long flags;

	spin_lock_irqsave(&io_request_lock, flags);

	/* Set the serial_number_at_timeout to the current serial_number */
	SCpnt->serial_number_at_timeout = SCpnt->serial_number;

	switch (SCpnt->internal_timeout & (IN_ABORT | IN_RESET | IN_RESET2 | IN_RESET3)) {
	case NORMAL_TIMEOUT:
		{
#ifdef DEBUG_TIMEOUT
			scsi_dump_status();
#endif
		}

		if (!scsi_abort(SCpnt, DID_TIME_OUT))
			break;
	case IN_ABORT:
		printk("SCSI host %d abort (pid %ld) timed out - resetting\n",
		       SCpnt->host->host_no, SCpnt->pid);
		if (!scsi_reset(SCpnt, SCSI_RESET_ASYNCHRONOUS))
			break;
	case IN_RESET:
	case (IN_ABORT | IN_RESET):
		/* This might be controversial, but if there is a bus hang,
		 * you might conceivably want the machine up and running
		 * esp if you have an ide disk.
		 */
		printk("SCSI host %d channel %d reset (pid %ld) timed out - "
		       "trying harder\n",
		       SCpnt->host->host_no, SCpnt->channel, SCpnt->pid);
		SCpnt->internal_timeout &= ~IN_RESET;
		SCpnt->internal_timeout |= IN_RESET2;
		scsi_reset(SCpnt,
		 SCSI_RESET_ASYNCHRONOUS | SCSI_RESET_SUGGEST_BUS_RESET);
		break;
	case IN_RESET2:
	case (IN_ABORT | IN_RESET2):
		/* Obviously the bus reset didn't work.
		 * Let's try even harder and call for an HBA reset.
		 * Maybe the HBA itself crashed and this will shake it loose.
		 */
		printk("SCSI host %d reset (pid %ld) timed out - trying to shake it loose\n",
		       SCpnt->host->host_no, SCpnt->pid);
		SCpnt->internal_timeout &= ~(IN_RESET | IN_RESET2);
		SCpnt->internal_timeout |= IN_RESET3;
		scsi_reset(SCpnt,
		SCSI_RESET_ASYNCHRONOUS | SCSI_RESET_SUGGEST_HOST_RESET);
		break;

	default:
		printk("SCSI host %d reset (pid %ld) timed out again -\n",
		       SCpnt->host->host_no, SCpnt->pid);
		printk("probably an unrecoverable SCSI bus or device hang.\n");
		break;

	}
	spin_unlock_irqrestore(&io_request_lock, flags);

}

/*
 *  From what I can find in scsi_obsolete.c, this function is only called
 *  by scsi_old_done and scsi_reset.  Both of these functions run with the
 *  io_request_lock already held, so we need do nothing here about grabbing
 *  any locks.
 */
static void scsi_request_sense(Scsi_Cmnd * SCpnt)
{
	SCpnt->flags |= WAS_SENSE | ASKED_FOR_SENSE;
	update_timeout(SCpnt, SENSE_TIMEOUT);


	memcpy((void *) SCpnt->cmnd, (void *) generic_sense,
	       sizeof(generic_sense));
	memset((void *) SCpnt->sense_buffer, 0,
	       sizeof(SCpnt->sense_buffer));

	SCpnt->cmnd[1] = SCpnt->lun << 5;
	SCpnt->cmnd[4] = sizeof(SCpnt->sense_buffer);

	SCpnt->request_buffer = &SCpnt->sense_buffer;
	SCpnt->request_bufflen = sizeof(SCpnt->sense_buffer);
	SCpnt->use_sg = 0;
	SCpnt->cmd_len = COMMAND_SIZE(SCpnt->cmnd[0]);
	SCpnt->result = 0;
	SCpnt->sc_data_direction = SCSI_DATA_READ;

        /*
         * Ugly, ugly.  The newer interfaces all assume that the lock
         * isn't held.  Mustn't disappoint, or we deadlock the system.
         */
        spin_unlock_irq(&io_request_lock);
	scsi_dispatch_cmd(SCpnt);
        spin_lock_irq(&io_request_lock);
}




static int check_sense(Scsi_Cmnd * SCpnt)
{
	/* If there is no sense information, request it.  If we have already
	 * requested it, there is no point in asking again - the firmware must
	 * be confused.
	 */
	if (((SCpnt->sense_buffer[0] & 0x70) >> 4) != 7) {
		if (!(SCpnt->flags & ASKED_FOR_SENSE))
			return SUGGEST_SENSE;
		else
			return SUGGEST_RETRY;
	}
	SCpnt->flags &= ~ASKED_FOR_SENSE;

#ifdef DEBUG_INIT
	printk("scsi%d, channel%d : ", SCpnt->host->host_no, SCpnt->channel);
	print_sense("", SCpnt);
	printk("\n");
#endif
	if (SCpnt->sense_buffer[2] & 0xe0)
		return SUGGEST_ABORT;

	switch (SCpnt->sense_buffer[2] & 0xf) {
	case NO_SENSE:
		return 0;
	case RECOVERED_ERROR:
		return SUGGEST_IS_OK;

	case ABORTED_COMMAND:
		return SUGGEST_RETRY;
	case NOT_READY:
	case UNIT_ATTENTION:
		/*
		 * If we are expecting a CC/UA because of a bus reset that we
		 * performed, treat this just as a retry.  Otherwise this is
		 * information that we should pass up to the upper-level driver
		 * so that we can deal with it there.
		 */
		if (SCpnt->device->expecting_cc_ua) {
			SCpnt->device->expecting_cc_ua = 0;
			return SUGGEST_RETRY;
		}
		return SUGGEST_ABORT;

		/* these three are not supported */
	case COPY_ABORTED:
	case VOLUME_OVERFLOW:
	case MISCOMPARE:

	case MEDIUM_ERROR:
		return SUGGEST_REMAP;
	case BLANK_CHECK:
	case DATA_PROTECT:
	case HARDWARE_ERROR:
	case ILLEGAL_REQUEST:
	default:
		return SUGGEST_ABORT;
	}
}

/* This function is the mid-level interrupt routine, which decides how
 *  to handle error conditions.  Each invocation of this function must
 *  do one and *only* one of the following:
 *
 *  (1) Call last_cmnd[host].done.  This is done for fatal errors and
 *      normal completion, and indicates that the handling for this
 *      request is complete.
 *  (2) Call internal_cmnd to requeue the command.  This will result in
 *      scsi_done being called again when the retry is complete.
 *  (3) Call scsi_request_sense.  This asks the host adapter/drive for
 *      more information about the error condition.  When the information
 *      is available, scsi_done will be called again.
 *  (4) Call reset().  This is sort of a last resort, and the idea is that
 *      this may kick things loose and get the drive working again.  reset()
 *      automatically calls scsi_request_sense, and thus scsi_done will be
 *      called again once the reset is complete.
 *
 *      If none of the above actions are taken, the drive in question
 *      will hang. If more than one of the above actions are taken by
 *      scsi_done, then unpredictable behavior will result.
 */
void scsi_old_done(Scsi_Cmnd * SCpnt)
{
	int status = 0;
	int exit = 0;
	int checked;
	int oldto;
	struct Scsi_Host *host = SCpnt->host;
        Scsi_Device * device = SCpnt->device;
	int result = SCpnt->result;
	SCpnt->serial_number = 0;
	SCpnt->serial_number_at_timeout = 0;
	oldto = update_timeout(SCpnt, 0);

#ifdef DEBUG_TIMEOUT
	if (result)
		printk("Non-zero result in scsi_done %x %d:%d\n",
		       result, SCpnt->target, SCpnt->lun);
#endif

	/* If we requested an abort, (and we got it) then fix up the return
	 *  status to say why
	 */
	if (host_byte(result) == DID_ABORT && SCpnt->abort_reason)
		SCpnt->result = result = (result & 0xff00ffff) |
		    (SCpnt->abort_reason << 16);


#define CMD_FINISHED 0
#define MAYREDO  1
#define REDO     3
#define PENDING  4

#ifdef DEBUG
	printk("In scsi_done(host = %d, result = %06x)\n", host->host_no, result);
#endif

	if (SCpnt->flags & SYNC_RESET) {
		/*
		   * The behaviou of scsi_reset(SYNC) was changed in 2.1.? .
		   * The scsi mid-layer does a REDO after every sync reset, the driver
		   * must not do that any more. In order to prevent old drivers from
		   * crashing, all scsi_done() calls during sync resets are ignored.
		 */
		printk("scsi%d: device driver called scsi_done() "
		       "for a synchronous reset.\n", SCpnt->host->host_no);