ncr53c9x.c

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		    this = (Scsi_Cmnd *) this->host_scribble) {
			if(this == SCptr) {
				*prev = (Scsi_Cmnd *) this->host_scribble;
				this->host_scribble = NULL;
				esp_release_dmabufs(esp, this);
				this->result = DID_ABORT << 16;
				this->done(this);
				if(don)
					esp->dma_ints_on(esp);
				return SCSI_ABORT_SUCCESS;
			}
		}
	}

	/* Yuck, the command to abort is disconnected, it is not
	 * worth trying to abort it now if something else is live
	 * on the bus at this time.  So, we let the SCSI code wait
	 * a little bit and try again later.
	 */
	if(esp->current_SC) {
		if(don)
			esp->dma_ints_on(esp);
		return SCSI_ABORT_BUSY;
	}

	/* It's disconnected, we have to reconnect to re-establish
	 * the nexus and tell the device to abort.  However, we really
	 * cannot 'reconnect' per se, therefore we tell the upper layer
	 * the safest thing we can.  This is, wait a bit, if nothing
	 * happens, we are really hung so reset the bus.
	 */

	if(don)
		esp->dma_ints_on(esp);
	return SCSI_ABORT_SNOOZE;
}

/* We've sent ESP_CMD_RS to the ESP, the interrupt had just
 * arrived indicating the end of the SCSI bus reset.  Our job
 * is to clean out the command queues and begin re-execution
 * of SCSI commands once more.
 */
static int esp_finish_reset(struct NCR_ESP *esp,
			    struct ESP_regs *eregs)
{
	Scsi_Cmnd *sp = esp->current_SC;

	/* Clean up currently executing command, if any. */
	if (sp != NULL) {
		esp_release_dmabufs(esp, sp);
		sp->result = (DID_RESET << 16);
		sp->scsi_done(sp);
		esp->current_SC = NULL;
	}

	/* Clean up disconnected queue, they have been invalidated
	 * by the bus reset.
	 */
	if (esp->disconnected_SC) {
		while((sp = remove_first_SC(&esp->disconnected_SC)) != NULL) {
			esp_release_dmabufs(esp, sp);
			sp->result = (DID_RESET << 16);
			sp->scsi_done(sp);
		}
	}

	/* SCSI bus reset is complete. */
	esp->resetting_bus = 0;

	/* Ok, now it is safe to get commands going once more. */
	if(esp->issue_SC)
		esp_exec_cmd(esp);

	return do_intr_end;
}

static int esp_do_resetbus(struct NCR_ESP *esp,
			   struct ESP_regs *eregs)
{
	ESPLOG(("esp%d: Resetting scsi bus\n", esp->esp_id));
	esp->resetting_bus = 1;
	esp_cmd(esp, eregs, ESP_CMD_RS);

	return do_intr_end;
}

/* Reset ESP chip, reset hanging bus, then kill active and
 * disconnected commands for targets without soft reset.
 */
int esp_reset(Scsi_Cmnd *SCptr, unsigned int how)
{
	struct NCR_ESP *esp = (struct NCR_ESP *) SCptr->host->hostdata;

	(void) esp_do_resetbus(esp, esp->eregs);
	return SCSI_RESET_PENDING;
}

/* Internal ESP done function. */
static void esp_done(struct NCR_ESP *esp, int error)
{
	Scsi_Cmnd *done_SC;

	if(esp->current_SC) {
		done_SC = esp->current_SC;
		esp->current_SC = NULL;
		esp_release_dmabufs(esp, done_SC);
		done_SC->result = error;
		done_SC->scsi_done(done_SC);

		/* Bus is free, issue any commands in the queue. */
		if(esp->issue_SC && !esp->current_SC)
			esp_exec_cmd(esp);
	} else {
		/* Panic is safe as current_SC is null so we may still
		 * be able to accept more commands to sync disk buffers.
		 */
		ESPLOG(("panicing\n"));
		panic("esp: done() called with NULL esp->current_SC");
	}
}

/* Wheee, ESP interrupt engine. */  

/* Forward declarations. */
static int esp_do_phase_determine(struct NCR_ESP *esp, 
				  struct ESP_regs *eregs);
static int esp_do_data_finale(struct NCR_ESP *esp, struct ESP_regs *eregs);
static int esp_select_complete(struct NCR_ESP *esp, struct ESP_regs *eregs);
static int esp_do_status(struct NCR_ESP *esp, struct ESP_regs *eregs);
static int esp_do_msgin(struct NCR_ESP *esp, struct ESP_regs *eregs);
static int esp_do_msgindone(struct NCR_ESP *esp, struct ESP_regs *eregs);
static int esp_do_msgout(struct NCR_ESP *esp, struct ESP_regs *eregs);
static int esp_do_cmdbegin(struct NCR_ESP *esp, struct ESP_regs *eregs);

#define sreg_datainp(__sreg)  (((__sreg) & ESP_STAT_PMASK) == ESP_DIP)
#define sreg_dataoutp(__sreg) (((__sreg) & ESP_STAT_PMASK) == ESP_DOP)

/* We try to avoid some interrupts by jumping ahead and see if the ESP
 * has gotten far enough yet.  Hence the following.
 */
static inline int skipahead1(struct NCR_ESP *esp, struct ESP_regs *eregs,
			     Scsi_Cmnd *scp, int prev_phase, int new_phase)
{
	if(scp->SCp.sent_command != prev_phase)
		return 0;

	if(esp->dma_irq_p(esp)) {
		/* Yes, we are able to save an interrupt. */
		esp->sreg = (esp_read(eregs->esp_status) & ~(ESP_STAT_INTR));
		esp->ireg = esp_read(eregs->esp_intrpt);
		if(!(esp->ireg & ESP_INTR_SR))
			return 0;
		else
			return do_reset_complete;
	}
	/* Ho hum, target is taking forever... */
	scp->SCp.sent_command = new_phase; /* so we don't recurse... */
	return do_intr_end;
}

static inline int skipahead2(struct NCR_ESP *esp,
			     struct ESP_regs *eregs,
			     Scsi_Cmnd *scp, int prev_phase1, int prev_phase2,
			     int new_phase)
{
	if(scp->SCp.sent_command != prev_phase1 &&
	   scp->SCp.sent_command != prev_phase2)
		return 0;
	if(esp->dma_irq_p(esp)) {
		/* Yes, we are able to save an interrupt. */
		esp->sreg = (esp_read(eregs->esp_status) & ~(ESP_STAT_INTR));
		esp->ireg = esp_read(eregs->esp_intrpt);
		if(!(esp->ireg & ESP_INTR_SR))
			return 0;
		else
			return do_reset_complete;
	}
	/* Ho hum, target is taking forever... */
	scp->SCp.sent_command = new_phase; /* so we don't recurse... */
	return do_intr_end;
}

/* Misc. esp helper macros. */
#define esp_setcount(__eregs, __cnt) \
	esp_write((__eregs)->esp_tclow, ((__cnt) & 0xff)); \
	esp_write((__eregs)->esp_tcmed, (((__cnt) >> 8) & 0xff))

#define esp_getcount(__eregs) \
	((esp_read((__eregs)->esp_tclow)&0xff) | \
	 ((esp_read((__eregs)->esp_tcmed)&0xff) << 8))

#define fcount(__esp, __eregs) \
	(esp_read((__eregs)->esp_fflags) & ESP_FF_FBYTES)

#define fnzero(__esp, __eregs) \
	(esp_read((__eregs)->esp_fflags) & ESP_FF_ONOTZERO)

/* XXX speculative nops unnecessary when continuing amidst a data phase
 * XXX even on esp100!!!  another case of flooding the bus with I/O reg
 * XXX writes...
 */
#define esp_maybe_nop(__esp, __eregs) \
	if((__esp)->erev == esp100) \
		esp_cmd((__esp), (__eregs), ESP_CMD_NULL)

#define sreg_to_dataphase(__sreg) \
	((((__sreg) & ESP_STAT_PMASK) == ESP_DOP) ? in_dataout : in_datain)

/* The ESP100 when in synchronous data phase, can mistake a long final
 * REQ pulse from the target as an extra byte, it places whatever is on
 * the data lines into the fifo.  For now, we will assume when this
 * happens that the target is a bit quirky and we don't want to
 * be talking synchronously to it anyways.  Regardless, we need to
 * tell the ESP to eat the extraneous byte so that we can proceed
 * to the next phase.
 */
static inline int esp100_sync_hwbug(struct NCR_ESP *esp, struct ESP_regs *eregs,
				    Scsi_Cmnd *sp, int fifocnt)
{
	/* Do not touch this piece of code. */
	if((!(esp->erev == esp100)) ||
	   (!(sreg_datainp((esp->sreg = esp_read(eregs->esp_status))) && !fifocnt) &&
	    !(sreg_dataoutp(esp->sreg) && !fnzero(esp, eregs)))) {
		if(sp->SCp.phase == in_dataout)
			esp_cmd(esp, eregs, ESP_CMD_FLUSH);
		return 0;
	} else {
		/* Async mode for this guy. */
		build_sync_nego_msg(esp, 0, 0);

		/* Ack the bogus byte, but set ATN first. */
		esp_cmd(esp, eregs, ESP_CMD_SATN);
		esp_cmd(esp, eregs, ESP_CMD_MOK);
		return 1;
	}
}

/* This closes the window during a selection with a reselect pending, because
 * we use DMA for the selection process the FIFO should hold the correct
 * contents if we get reselected during this process.  So we just need to
 * ack the possible illegal cmd interrupt pending on the esp100.
 */
static inline int esp100_reconnect_hwbug(struct NCR_ESP *esp,
					 struct ESP_regs *eregs)
{
	volatile unchar junk;

	if(esp->erev != esp100)
		return 0;
	junk = esp_read(eregs->esp_intrpt);

	if(junk & ESP_INTR_SR)
		return 1;
	return 0;
}

/* This verifies the BUSID bits during a reselection so that we know which
 * target is talking to us.
 */
static inline int reconnect_target(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	int it, me = esp->scsi_id_mask, targ = 0;

	if(2 != fcount(esp, eregs))
		return -1;
	it = esp_read(eregs->esp_fdata);
	if(!(it & me))
		return -1;
	it &= ~me;
	if(it & (it - 1))
		return -1;
	while(!(it & 1))
		targ++, it >>= 1;
	return targ;
}

/* This verifies the identify from the target so that we know which lun is
 * being reconnected.
 */
static inline int reconnect_lun(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	int lun;

	if((esp->sreg & ESP_STAT_PMASK) != ESP_MIP)
		return -1;
	lun = esp_read(eregs->esp_fdata);

	/* Yes, you read this correctly.  We report lun of zero
	 * if we see parity error.  ESP reports parity error for
	 * the lun byte, and this is the only way to hope to recover
	 * because the target is connected.
	 */
	if(esp->sreg & ESP_STAT_PERR)
		return 0;

	/* Check for illegal bits being set in the lun. */
	if((lun & 0x40) || !(lun & 0x80))
		return -1;

	return lun & 7;
}

/* This puts the driver in a state where it can revitalize a command that
 * is being continued due to reselection.
 */
static inline void esp_connect(struct NCR_ESP *esp, struct ESP_regs *eregs,
			       Scsi_Cmnd *sp)
{
	Scsi_Device *dp = sp->device;

	if(esp->prev_soff  != dp->sync_max_offset ||
	   esp->prev_stp   != dp->sync_min_period ||
	   (esp->erev > esp100a &&
	    esp->prev_cfg3 != esp->config3[sp->target])) {
		esp->prev_soff = dp->sync_max_offset;
		esp_write(eregs->esp_soff, esp->prev_soff);
		esp->prev_stp = dp->sync_min_period;
		esp_write(eregs->esp_stp, esp->prev_stp);
		if(esp->erev > esp100a) {
			esp->prev_cfg3 = esp->config3[sp->target];
			esp_write(eregs->esp_cfg3, esp->prev_cfg3);
		} 
	}
	esp->current_SC = sp;
}

/* This will place the current working command back into the issue queue
 * if we are to receive a reselection amidst a selection attempt.
 */
static inline void esp_reconnect(struct NCR_ESP *esp, Scsi_Cmnd *sp)
{
	if(!esp->disconnected_SC)
		ESPLOG(("esp%d: Weird, being reselected but disconnected "
			"command queue is empty.\n", esp->esp_id));
	esp->snip = 0;
	esp->current_SC = 0;
	sp->SCp.phase = not_issued;
	append_SC(&esp->issue_SC, sp);
}

/* Begin message in phase. */
static int esp_do_msgin(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	esp_cmd(esp, eregs, ESP_CMD_FLUSH);
	esp_maybe_nop(esp, eregs);
	esp_cmd(esp, eregs, ESP_CMD_TI);
	esp->msgin_len = 1;
	esp->msgin_ctr = 0;
	esp_advance_phase(esp->current_SC, in_msgindone);
	return do_work_bus;
}

static inline void advance_sg(struct NCR_ESP *esp, Scsi_Cmnd *sp)
{
	++sp->SCp.buffer;
	--sp->SCp.buffers_residual;
	sp->SCp.this_residual = sp->SCp.buffer->length;
	if (esp->dma_advance_sg)
		esp->dma_advance_sg (sp);
	else
		sp->SCp.ptr = (char *)virt_to_phys(sp->SCp.buffer->address);
}

/* Please note that the way I've coded these routines is that I _always_
 * check for a disconnect during any and all information transfer
 * phases.  The SCSI standard states that the target _can_ cause a BUS
 * FREE condition by dropping all MSG/CD/IO/BSY signals.  Also note
 * that during information transfer phases the target controls every
 * change in phase, the only thing the initiator can do is "ask" for
 * a message out phase by driving ATN true.  The target can, and sometimes
 * will, completely ignore this request so we cannot assume anything when
 * we try to force a message out phase to abort/reset a target.  Most of
 * the time the target will eventually be nice and go to message out, so
 * we may have to hold on to our state about what we want to tell the target
 * for some period of time.
 */

/* I think I have things working here correctly.  Even partial transfers
 * within a buffer or sub-buffer should not upset us at all no matter
 * how bad the target and/or ESP fucks things up.
 */
static int esp_do_data(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	Scsi_Cmnd *SCptr = esp->current_SC;
	int thisphase, hmuch;

	ESPDATA(("esp_do_data: "));
	esp_maybe_nop(esp, eregs);
	thisphase = sreg_to_dataphase(esp->sreg);
	esp_advance_phase(SCptr, thisphase);
	ESPDATA(("newphase<%s> ", (thisphase == in_datain) ? "DATAIN" : "DATAOUT"));
	hmuch = esp->dma_can_transfer(esp, SCptr);

	/*
	 * XXX MSch: cater for PIO transfer here; PIO used if hmuch == 0
	 */
	if (hmuch) {	/* DMA */
		/*
		 * DMA
		 */
		ESPDATA(("hmuch<%d> ", hmuch));
		esp->current_transfer_size = hmuch;
		esp_setcount(eregs, (esp->fas_premature_intr_workaround ?
				     (hmuch + 0x40) : hmuch));
		esp->dma_setup(esp, (__u32)((unsigned long)SCptr->SCp.ptr), 
			       hmuch, (thisphase == in_datain));
		ESPDATA(("DMA|TI --> do_intr_end\n"));
		esp_cmd(esp, eregs, ESP_CMD_DMA | ESP_CMD_TI);
		return do_intr_end;
		/*
		 * end DMA
		 */
	} else {
		/*
		 * PIO
		 */
		int oldphase, i = 0; /* or where we left off last time ?? esp->current_data ?? */
		int fifocnt = 0;

		oldphase = esp_read(eregs->esp_status) & ESP_STAT_PMASK;

		/*
		 * polled transfer; ugly, can we make this happen in a DRQ 
		 * interrupt handler ??
		 * requires keeping track of state information in host or 
		 * command struct!
		 * Problem: I've never seen a DRQ happen on Mac, not even
		 * with ESP_CMD_DMA ...
		 */

		/* figure out how much needs to be transfered */
		hmuch = SCptr->SCp.this_residual;
		ESPDATA(("hmuch<%d> pio ", hmuch));
		esp->current_transfer_size = hmuch;

		/* tell the ESP ... */
		esp_setcount(eregs, hmuch);

		/* loop */
		while (hmuch) {
			int j, fifo_stuck = 0, newphase;
			unsigned long flags, timeout;
#if 0
			if ( i % 10 )
				ESPDATA(("\r"));
			else
				ESPDATA(( /*"\n"*/ "\r"));
#endif
			save_flags(flags);
#if 0
			cli();
#endif
			if(thisphase == in_datain) {
				/* 'go' ... */ 
				esp_cmd(esp, eregs, ESP_CMD_TI);

				/* wait for data */
				timeout = 1000000;
				while (!((esp->sreg=esp_read(eregs->esp_status)) & ESP_STAT_INTR) && --timeout)
					udelay(2);
				if (timeout == 0)
					printk("DRQ datain timeout! \n");

				newphase = esp->sreg & ESP_STAT_PMASK;