ncr53c9x.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

			esp->dma_mmu_get_scsi_sgl(esp, sp);
		else
			sp->SCp.ptr =
				(char *) virt_to_phys(sp->SCp.buffer->address);
	}
}

static void esp_release_dmabufs(struct NCR_ESP *esp, Scsi_Cmnd *sp)
{
	if(sp->use_sg == 0) {
		if (esp->dma_mmu_release_scsi_one)
			esp->dma_mmu_release_scsi_one(esp, sp);
	} else {
		if (esp->dma_mmu_release_scsi_sgl)
			esp->dma_mmu_release_scsi_sgl(esp, sp);
	}
}

static void esp_restore_pointers(struct NCR_ESP *esp, Scsi_Cmnd *sp)
{
	struct esp_pointers *ep = &esp->data_pointers[sp->target];

	sp->SCp.ptr = ep->saved_ptr;
	sp->SCp.buffer = ep->saved_buffer;
	sp->SCp.this_residual = ep->saved_this_residual;
	sp->SCp.buffers_residual = ep->saved_buffers_residual;
}

static void esp_save_pointers(struct NCR_ESP *esp, Scsi_Cmnd *sp)
{
	struct esp_pointers *ep = &esp->data_pointers[sp->target];

	ep->saved_ptr = sp->SCp.ptr;
	ep->saved_buffer = sp->SCp.buffer;
	ep->saved_this_residual = sp->SCp.this_residual;
	ep->saved_buffers_residual = sp->SCp.buffers_residual;
}

/* Some rules:
 *
 *   1) Never ever panic while something is live on the bus.
 *      If there is to be any chance of syncing the disks this
 *      rule is to be obeyed.
 *
 *   2) Any target that causes a foul condition will no longer
 *      have synchronous transfers done to it, no questions
 *      asked.
 *
 *   3) Keep register accesses to a minimum.  Think about some
 *      day when we have Xbus machines this is running on and
 *      the ESP chip is on the other end of the machine on a
 *      different board from the cpu where this is running.
 */

/* Fire off a command.  We assume the bus is free and that the only
 * case where we could see an interrupt is where we have disconnected
 * commands active and they are trying to reselect us.
 */
static inline void esp_check_cmd(struct NCR_ESP *esp, Scsi_Cmnd *sp)
{
	switch(sp->cmd_len) {
	case 6:
	case 10:
	case 12:
		esp->esp_slowcmd = 0;
		break;

	default:
		esp->esp_slowcmd = 1;
		esp->esp_scmdleft = sp->cmd_len;
		esp->esp_scmdp = &sp->cmnd[0];
		break;
	};
}

static inline void build_sync_nego_msg(struct NCR_ESP *esp, int period, int offset)
{
	esp->cur_msgout[0] = EXTENDED_MESSAGE;
	esp->cur_msgout[1] = 3;
	esp->cur_msgout[2] = EXTENDED_SDTR;
	esp->cur_msgout[3] = period;
	esp->cur_msgout[4] = offset;
	esp->msgout_len = 5;
}

static void esp_exec_cmd(struct NCR_ESP *esp)
{
	struct ESP_regs *eregs = esp->eregs;
	Scsi_Cmnd *SCptr;
	Scsi_Device *SDptr;
	volatile unchar *cmdp = esp->esp_command;
	unsigned char the_esp_command;
	int lun, target;
	int i;

	/* Hold off if we have disconnected commands and
	 * an IRQ is showing...
	 */
	if(esp->disconnected_SC && esp->dma_irq_p(esp))
		return;

	/* Grab first member of the issue queue. */
	SCptr = esp->current_SC = remove_first_SC(&esp->issue_SC);

	/* Safe to panic here because current_SC is null. */
	if(!SCptr)
		panic("esp: esp_exec_cmd and issue queue is NULL");

	SDptr = SCptr->device;
	lun = SCptr->lun;
	target = SCptr->target;

	esp->snip = 0;
	esp->msgout_len = 0;

	/* Send it out whole, or piece by piece?   The ESP
	 * only knows how to automatically send out 6, 10,
	 * and 12 byte commands.  I used to think that the
	 * Linux SCSI code would never throw anything other
	 * than that to us, but then again there is the
	 * SCSI generic driver which can send us anything.
	 */
	esp_check_cmd(esp, SCptr);

	/* If arbitration/selection is successful, the ESP will leave
	 * ATN asserted, causing the target to go into message out
	 * phase.  The ESP will feed the target the identify and then
	 * the target can only legally go to one of command,
	 * datain/out, status, or message in phase, or stay in message
	 * out phase (should we be trying to send a sync negotiation
	 * message after the identify).  It is not allowed to drop
	 * BSY, but some buggy targets do and we check for this
	 * condition in the selection complete code.  Most of the time
	 * we'll make the command bytes available to the ESP and it
	 * will not interrupt us until it finishes command phase, we
	 * cannot do this for command sizes the ESP does not
	 * understand and in this case we'll get interrupted right
	 * when the target goes into command phase.
	 *
	 * It is absolutely _illegal_ in the presence of SCSI-2 devices
	 * to use the ESP select w/o ATN command.  When SCSI-2 devices are
	 * present on the bus we _must_ always go straight to message out
	 * phase with an identify message for the target.  Being that
	 * selection attempts in SCSI-1 w/o ATN was an option, doing SCSI-2
	 * selections should not confuse SCSI-1 we hope.
	 */

	if(SDptr->sync) {
		/* this targets sync is known */
#ifdef CONFIG_SCSI_MAC_ESP
do_sync_known:
#endif
		if(SDptr->disconnect)
			*cmdp++ = IDENTIFY(1, lun);
		else
			*cmdp++ = IDENTIFY(0, lun);

		if(esp->esp_slowcmd) {
			the_esp_command = (ESP_CMD_SELAS | ESP_CMD_DMA);
			esp_advance_phase(SCptr, in_slct_stop);
		} else {
			the_esp_command = (ESP_CMD_SELA | ESP_CMD_DMA);
			esp_advance_phase(SCptr, in_slct_norm);
		}
	} else if(!(esp->targets_present & (1<<target)) || !(SDptr->disconnect)) {
		/* After the bootup SCSI code sends both the
		 * TEST_UNIT_READY and INQUIRY commands we want
		 * to at least attempt allowing the device to
		 * disconnect.
		 */
		ESPMISC(("esp: Selecting device for first time. target=%d "
			 "lun=%d\n", target, SCptr->lun));
		if(!SDptr->borken && !SDptr->disconnect)
			SDptr->disconnect = 1;

		*cmdp++ = IDENTIFY(0, lun);
		esp->prevmsgout = NOP;
		esp_advance_phase(SCptr, in_slct_norm);
		the_esp_command = (ESP_CMD_SELA | ESP_CMD_DMA);

		/* Take no chances... */
		SDptr->sync_max_offset = 0;
		SDptr->sync_min_period = 0;
	} else {
		int toshiba_cdrom_hwbug_wkaround = 0;

#ifdef CONFIG_SCSI_MAC_ESP
		/* Never allow synchronous transfers (disconnect OK) on
		 * Macintosh. Well, maybe later when we figured out how to 
		 * do DMA on the machines that support it ...
		 */
		SDptr->disconnect = 1;
		SDptr->sync_max_offset = 0;
		SDptr->sync_min_period = 0;
		SDptr->sync = 1;
		esp->snip = 0;
		goto do_sync_known;
#endif
		/* We've talked to this guy before,
		 * but never negotiated.  Let's try
		 * sync negotiation.
		 */
		if(!SDptr->borken) {
			if((SDptr->type == TYPE_ROM) &&
			   (!strncmp(SDptr->vendor, "TOSHIBA", 7))) {
				/* Nice try sucker... */
				ESPMISC(("esp%d: Disabling sync for buggy "
					 "Toshiba CDROM.\n", esp->esp_id));
				toshiba_cdrom_hwbug_wkaround = 1;
				build_sync_nego_msg(esp, 0, 0);
			} else {
				build_sync_nego_msg(esp, esp->sync_defp, 15);
			}
		} else {
			build_sync_nego_msg(esp, 0, 0);
		}
		SDptr->sync = 1;
		esp->snip = 1;

		/* A fix for broken SCSI1 targets, when they disconnect
		 * they lock up the bus and confuse ESP.  So disallow
		 * disconnects for SCSI1 targets for now until we
		 * find a better fix.
		 *
		 * Addendum: This is funny, I figured out what was going
		 *           on.  The blotzed SCSI1 target would disconnect,
		 *           one of the other SCSI2 targets or both would be
		 *           disconnected as well.  The SCSI1 target would
		 *           stay disconnected long enough that we start
		 *           up a command on one of the SCSI2 targets.  As
		 *           the ESP is arbitrating for the bus the SCSI1
		 *           target begins to arbitrate as well to reselect
		 *           the ESP.  The SCSI1 target refuses to drop it's
		 *           ID bit on the data bus even though the ESP is
		 *           at ID 7 and is the obvious winner for any
		 *           arbitration.  The ESP is a poor sport and refuses
		 *           to lose arbitration, it will continue indefinately
		 *           trying to arbitrate for the bus and can only be
		 *           stopped via a chip reset or SCSI bus reset.
		 *           Therefore _no_ disconnects for SCSI1 targets
		 *           thank you very much. ;-)
		 */
		if(((SDptr->scsi_level < 3) && (SDptr->type != TYPE_TAPE)) ||
		   toshiba_cdrom_hwbug_wkaround || SDptr->borken) {
			ESPMISC((KERN_INFO "esp%d: Disabling DISCONNECT for target %d "
				 "lun %d\n", esp->esp_id, SCptr->target, SCptr->lun));
			SDptr->disconnect = 0;
			*cmdp++ = IDENTIFY(0, lun);
		} else {
			*cmdp++ = IDENTIFY(1, lun);
		}

		/* ESP fifo is only so big...
		 * Make this look like a slow command.
		 */
		esp->esp_slowcmd = 1;
		esp->esp_scmdleft = SCptr->cmd_len;
		esp->esp_scmdp = &SCptr->cmnd[0];

		the_esp_command = (ESP_CMD_SELAS | ESP_CMD_DMA);
		esp_advance_phase(SCptr, in_slct_msg);
	}

	if(!esp->esp_slowcmd)
		for(i = 0; i < SCptr->cmd_len; i++)
			*cmdp++ = SCptr->cmnd[i];

	esp_write(eregs->esp_busid, (target & 7));
	if (esp->prev_soff != SDptr->sync_max_offset ||
	    esp->prev_stp  != SDptr->sync_min_period ||
	    (esp->erev > esp100a &&
	     esp->prev_cfg3 != esp->config3[target])) {
		esp->prev_soff = SDptr->sync_max_offset;
		esp_write(eregs->esp_soff, esp->prev_soff);
		esp->prev_stp = SDptr->sync_min_period;
		esp_write(eregs->esp_stp, esp->prev_stp); 
		if(esp->erev > esp100a) {
			esp->prev_cfg3 = esp->config3[target];
			esp_write(eregs->esp_cfg3, esp->prev_cfg3);
		}
	}
	i = (cmdp - esp->esp_command);

	/* Set up the DMA and ESP counters */
	if(esp->do_pio_cmds){
		int j = 0;

		/* 
		 * XXX MSch:
		 *
		 * It seems this is required, at least to clean up
		 * after failed commands when using PIO mode ...
		 */
		esp_cmd(esp, eregs, ESP_CMD_FLUSH);

		for(;j<i;j++)
			esp_write(eregs->esp_fdata, esp->esp_command[j]);
		the_esp_command &= ~ESP_CMD_DMA;

		/* Tell ESP to "go". */
		esp_cmd(esp, eregs, the_esp_command);
	} else {
		/* Set up the ESP counters */
		esp_write(eregs->esp_tclow, i);
		esp_write(eregs->esp_tcmed, 0);
		esp->dma_init_write(esp, esp->esp_command_dvma, i);

		/* Tell ESP to "go". */
		esp_cmd(esp, eregs, the_esp_command);
	}
}

/* Queue a SCSI command delivered from the mid-level Linux SCSI code. */
int esp_queue(Scsi_Cmnd *SCpnt, void (*done)(Scsi_Cmnd *))
{
	struct NCR_ESP *esp;

	/* Set up func ptr and initial driver cmd-phase. */
	SCpnt->scsi_done = done;
	SCpnt->SCp.phase = not_issued;

	esp = (struct NCR_ESP *) SCpnt->host->hostdata;

	if(esp->dma_led_on)
		esp->dma_led_on(esp);

	/* We use the scratch area. */
	ESPQUEUE(("esp_queue: target=%d lun=%d ", SCpnt->target, SCpnt->lun));
	ESPDISC(("N<%02x,%02x>", SCpnt->target, SCpnt->lun));

	esp_get_dmabufs(esp, SCpnt);
	esp_save_pointers(esp, SCpnt); /* FIXME for tag queueing */

	SCpnt->SCp.Status           = CHECK_CONDITION;
	SCpnt->SCp.Message          = 0xff;
	SCpnt->SCp.sent_command     = 0;

	/* Place into our queue. */
	if(SCpnt->cmnd[0] == REQUEST_SENSE) {
		ESPQUEUE(("RQSENSE\n"));
		prepend_SC(&esp->issue_SC, SCpnt);
	} else {
		ESPQUEUE(("\n"));
		append_SC(&esp->issue_SC, SCpnt);
	}

	/* Run it now if we can. */
	if(!esp->current_SC && !esp->resetting_bus)
		esp_exec_cmd(esp);

	return 0;
}

/* Only queuing supported in this ESP driver. */
int esp_command(Scsi_Cmnd *SCpnt)
{
#ifdef DEBUG_ESP
	struct NCR_ESP *esp = (struct NCR_ESP *) SCpnt->host->hostdata;
#endif

	ESPLOG(("esp%d: esp_command() called...\n", esp->esp_id));
	return -1;
}

/* Dump driver state. */
static void esp_dump_cmd(Scsi_Cmnd *SCptr)
{
	ESPLOG(("[tgt<%02x> lun<%02x> "
		"pphase<%s> cphase<%s>]",
		SCptr->target, SCptr->lun,
		phase_string(SCptr->SCp.sent_command),
		phase_string(SCptr->SCp.phase)));
}

static void esp_dump_state(struct NCR_ESP *esp, 
			   struct ESP_regs *eregs)
{
	Scsi_Cmnd *SCptr = esp->current_SC;
#ifdef DEBUG_ESP_CMDS
	int i;
#endif

	ESPLOG(("esp%d: dumping state\n", esp->esp_id));
	
	/* Print DMA status */
	esp->dma_dump_state(esp);

	ESPLOG(("esp%d: SW [sreg<%02x> sstep<%02x> ireg<%02x>]\n",
		esp->esp_id, esp->sreg, esp->seqreg, esp->ireg));
	ESPLOG(("esp%d: HW reread [sreg<%02x> sstep<%02x> ireg<%02x>]\n",
		esp->esp_id, esp_read(eregs->esp_status), esp_read(eregs->esp_sstep),
		esp_read(eregs->esp_intrpt)));
#ifdef DEBUG_ESP_CMDS
	printk("esp%d: last ESP cmds [", esp->esp_id);
	i = (esp->espcmdent - 1) & 31;
	printk("<");
	esp_print_cmd(esp->espcmdlog[i]);
	printk(">");
	i = (i - 1) & 31;
	printk("<");
	esp_print_cmd(esp->espcmdlog[i]);
	printk(">");
	i = (i - 1) & 31;
	printk("<");
	esp_print_cmd(esp->espcmdlog[i]);
	printk(">");
	i = (i - 1) & 31;
	printk("<");
	esp_print_cmd(esp->espcmdlog[i]);
	printk(">");
	printk("]\n");
#endif /* (DEBUG_ESP_CMDS) */

	if(SCptr) {
		ESPLOG(("esp%d: current command ", esp->esp_id));
		esp_dump_cmd(SCptr);
	}
	ESPLOG(("\n"));
	SCptr = esp->disconnected_SC;
	ESPLOG(("esp%d: disconnected ", esp->esp_id));
	while(SCptr) {
		esp_dump_cmd(SCptr);
		SCptr = (Scsi_Cmnd *) SCptr->host_scribble;
	}
	ESPLOG(("\n"));
}

/* Abort a command. */
int esp_abort(Scsi_Cmnd *SCptr)
{
	struct NCR_ESP *esp = (struct NCR_ESP *) SCptr->host->hostdata;
	struct ESP_regs *eregs = esp->eregs;
	int don;

	ESPLOG(("esp%d: Aborting command\n", esp->esp_id));
	esp_dump_state(esp, eregs);

	/* Wheee, if this is the current command on the bus, the
	 * best we can do is assert ATN and wait for msgout phase.
	 * This should even fix a hung SCSI bus when we lose state
	 * in the driver and timeout because the eventual phase change
	 * will cause the ESP to (eventually) give an interrupt.
	 */
	if(esp->current_SC == SCptr) {
		esp->cur_msgout[0] = ABORT;
		esp->msgout_len = 1;
		esp->msgout_ctr = 0;
		esp_cmd(esp, eregs, ESP_CMD_SATN);
		return SCSI_ABORT_PENDING;
	}

	/* If it is still in the issue queue then we can safely
	 * call the completion routine and report abort success.
	 */
	don = esp->dma_ports_p(esp);
	if(don) {
		esp->dma_ints_off(esp);
		synchronize_irq();
	}
	if(esp->issue_SC) {
		Scsi_Cmnd **prev, *this;
		for(prev = (&esp->issue_SC), this = esp->issue_SC;
		    this;
		    prev = (Scsi_Cmnd **) &(this->host_scribble),