mesh.c

linux 内核源代码

	dlog(ms, "error err/exc/fc/cl=%.8x",
	     MKWORD(err, exc, mr->fifo_count, mr->count_lo));
	if (err & ERR_SCSIRESET) {
		/* SCSI bus was reset */
		printk(KERN_INFO "mesh: SCSI bus reset detected: "
		       "waiting for end...");
		while ((in_8(&mr->bus_status1) & BS1_RST) != 0)
			udelay(1);
		printk("done\n");
		handle_reset(ms);
		/* request_q is empty, no point in mesh_start() */
		return;
	}
	if (err & ERR_UNEXPDISC) {
		/* Unexpected disconnect */
		if (exc & EXC_RESELECTED) {
			reselected(ms);
			return;
		}
		if (!ms->aborting) {
			printk(KERN_WARNING "mesh: target %d aborted\n",
			       ms->conn_tgt);
			dumplog(ms, ms->conn_tgt);
			dumpslog(ms);
		}
		out_8(&mr->interrupt, INT_CMDDONE);
		ms->stat = DID_ABORT;
		mesh_done(ms, 1);
		return;
	}
	if (err & ERR_PARITY) {
		if (ms->msgphase == msg_in) {
			printk(KERN_ERR "mesh: msg parity error, target %d\n",
			       ms->conn_tgt);
			ms->msgout[0] = MSG_PARITY_ERROR;
			ms->n_msgout = 1;
			ms->msgphase = msg_in_bad;
			cmd_complete(ms);
			return;
		}
		if (ms->stat == DID_OK) {
			printk(KERN_ERR "mesh: parity error, target %d\n",
			       ms->conn_tgt);
			ms->stat = DID_PARITY;
		}
		count = (mr->count_hi << 8) + mr->count_lo;
		if (count == 0) {
			cmd_complete(ms);
		} else {
			/* reissue the data transfer command */
			out_8(&mr->sequence, mr->sequence);
		}
		return;
	}
	if (err & ERR_SEQERR) {
		if (exc & EXC_RESELECTED) {
			/* This can happen if we issue a command to
			   get the bus just after the target reselects us. */
			static int mesh_resel_seqerr;
			mesh_resel_seqerr++;
			reselected(ms);
			return;
		}
		if (exc == EXC_PHASEMM) {
			static int mesh_phasemm_seqerr;
			mesh_phasemm_seqerr++;
			phase_mismatch(ms);
			return;
		}
		printk(KERN_ERR "mesh: sequence error (err=%x exc=%x)\n",
		       err, exc);
	} else {
		printk(KERN_ERR "mesh: unknown error %x (exc=%x)\n", err, exc);
	}
	mesh_dump_regs(ms);
	dumplog(ms, ms->conn_tgt);
	if (ms->phase > selecting && (in_8(&mr->bus_status1) & BS1_BSY)) {
		/* try to do what the target wants */
		do_abort(ms);
		phase_mismatch(ms);
		return;
	}
	ms->stat = DID_ERROR;
	mesh_done(ms, 1);
}

static void handle_exception(struct mesh_state *ms)
{
	int exc;
	volatile struct mesh_regs __iomem *mr = ms->mesh;

	exc = in_8(&mr->exception);
	out_8(&mr->interrupt, INT_EXCEPTION | INT_CMDDONE);
	if (exc & EXC_RESELECTED) {
		static int mesh_resel_exc;
		mesh_resel_exc++;
		reselected(ms);
	} else if (exc == EXC_ARBLOST) {
		printk(KERN_DEBUG "mesh: lost arbitration\n");
		ms->stat = DID_BUS_BUSY;
		mesh_done(ms, 1);
	} else if (exc == EXC_SELTO) {
		/* selection timed out */
		ms->stat = DID_BAD_TARGET;
		mesh_done(ms, 1);
	} else if (exc == EXC_PHASEMM) {
		/* target wants to do something different:
		   find out what it wants and do it. */
		phase_mismatch(ms);
	} else {
		printk(KERN_ERR "mesh: can't cope with exception %x\n", exc);
		mesh_dump_regs(ms);
		dumplog(ms, ms->conn_tgt);
		do_abort(ms);
		phase_mismatch(ms);
	}
}

static void handle_msgin(struct mesh_state *ms)
{
	int i, code;
	struct scsi_cmnd *cmd = ms->current_req;
	struct mesh_target *tp = &ms->tgts[ms->conn_tgt];

	if (ms->n_msgin == 0)
		return;
	code = ms->msgin[0];
	if (ALLOW_DEBUG(ms->conn_tgt)) {
		printk(KERN_DEBUG "got %d message bytes:", ms->n_msgin);
		for (i = 0; i < ms->n_msgin; ++i)
			printk(" %x", ms->msgin[i]);
		printk("\n");
	}
	dlog(ms, "msgin msg=%.8x",
	     MKWORD(ms->n_msgin, code, ms->msgin[1], ms->msgin[2]));

	ms->expect_reply = 0;
	ms->n_msgout = 0;
	if (ms->n_msgin < msgin_length(ms))
		goto reject;
	if (cmd)
		cmd->SCp.Message = code;
	switch (code) {
	case COMMAND_COMPLETE:
		break;
	case EXTENDED_MESSAGE:
		switch (ms->msgin[2]) {
		case EXTENDED_MODIFY_DATA_POINTER:
			ms->data_ptr += (ms->msgin[3] << 24) + ms->msgin[6]
				+ (ms->msgin[4] << 16) + (ms->msgin[5] << 8);
			break;
		case EXTENDED_SDTR:
			if (tp->sdtr_state != sdtr_sent) {
				/* reply with an SDTR */
				add_sdtr_msg(ms);
				/* limit period to at least his value,
				   offset to no more than his */
				if (ms->msgout[3] < ms->msgin[3])
					ms->msgout[3] = ms->msgin[3];
				if (ms->msgout[4] > ms->msgin[4])
					ms->msgout[4] = ms->msgin[4];
				set_sdtr(ms, ms->msgout[3], ms->msgout[4]);
				ms->msgphase = msg_out;
			} else {
				set_sdtr(ms, ms->msgin[3], ms->msgin[4]);
			}
			break;
		default:
			goto reject;
		}
		break;
	case SAVE_POINTERS:
		tp->saved_ptr = ms->data_ptr;
		break;
	case RESTORE_POINTERS:
		ms->data_ptr = tp->saved_ptr;
		break;
	case DISCONNECT:
		ms->phase = disconnecting;
		break;
	case ABORT:
		break;
	case MESSAGE_REJECT:
		if (tp->sdtr_state == sdtr_sent)
			set_sdtr(ms, 0, 0);
		break;
	case NOP:
		break;
	default:
		if (IDENTIFY_BASE <= code && code <= IDENTIFY_BASE + 7) {
			if (cmd == NULL) {
				do_abort(ms);
				ms->msgphase = msg_out;
			} else if (code != cmd->device->lun + IDENTIFY_BASE) {
				printk(KERN_WARNING "mesh: lun mismatch "
				       "(%d != %d) on reselection from "
				       "target %d\n", code - IDENTIFY_BASE,
				       cmd->device->lun, ms->conn_tgt);
			}
			break;
		}
		goto reject;
	}
	return;

 reject:
	printk(KERN_WARNING "mesh: rejecting message from target %d:",
	       ms->conn_tgt);
	for (i = 0; i < ms->n_msgin; ++i)
		printk(" %x", ms->msgin[i]);
	printk("\n");
	ms->msgout[0] = MESSAGE_REJECT;
	ms->n_msgout = 1;
	ms->msgphase = msg_out;
}

/*
 * Set up DMA commands for transferring data.
 */
static void set_dma_cmds(struct mesh_state *ms, struct scsi_cmnd *cmd)
{
	int i, dma_cmd, total, off, dtot;
	struct scatterlist *scl;
	struct dbdma_cmd *dcmds;

	dma_cmd = ms->tgts[ms->conn_tgt].data_goes_out?
		OUTPUT_MORE: INPUT_MORE;
	dcmds = ms->dma_cmds;
	dtot = 0;
	if (cmd) {
		int nseg;

		cmd->SCp.this_residual = scsi_bufflen(cmd);

		nseg = scsi_dma_map(cmd);
		BUG_ON(nseg < 0);

		if (nseg) {
			total = 0;
			off = ms->data_ptr;

			scsi_for_each_sg(cmd, scl, nseg, i) {
				u32 dma_addr = sg_dma_address(scl);
				u32 dma_len = sg_dma_len(scl);
				
				total += scl->length;
				if (off >= dma_len) {
					off -= dma_len;
					continue;
				}
				if (dma_len > 0xffff)
					panic("mesh: scatterlist element >= 64k");
				st_le16(&dcmds->req_count, dma_len - off);
				st_le16(&dcmds->command, dma_cmd);
				st_le32(&dcmds->phy_addr, dma_addr + off);
				dcmds->xfer_status = 0;
				++dcmds;
				dtot += dma_len - off;
				off = 0;
			}
		}
	}
	if (dtot == 0) {
		/* Either the target has overrun our buffer,
		   or the caller didn't provide a buffer. */
		static char mesh_extra_buf[64];

		dtot = sizeof(mesh_extra_buf);
		st_le16(&dcmds->req_count, dtot);
		st_le32(&dcmds->phy_addr, virt_to_phys(mesh_extra_buf));
		dcmds->xfer_status = 0;
		++dcmds;
	}
	dma_cmd += OUTPUT_LAST - OUTPUT_MORE;
	st_le16(&dcmds[-1].command, dma_cmd);
	memset(dcmds, 0, sizeof(*dcmds));
	st_le16(&dcmds->command, DBDMA_STOP);
	ms->dma_count = dtot;
}

static void halt_dma(struct mesh_state *ms)
{
	volatile struct dbdma_regs __iomem *md = ms->dma;
	volatile struct mesh_regs __iomem *mr = ms->mesh;
	struct scsi_cmnd *cmd = ms->current_req;
	int t, nb;

	if (!ms->tgts[ms->conn_tgt].data_goes_out) {
		/* wait a little while until the fifo drains */
		t = 50;
		while (t > 0 && in_8(&mr->fifo_count) != 0
		       && (in_le32(&md->status) & ACTIVE) != 0) {
			--t;
			udelay(1);
		}
	}
	out_le32(&md->control, RUN << 16);	/* turn off RUN bit */
	nb = (mr->count_hi << 8) + mr->count_lo;
	dlog(ms, "halt_dma fc/count=%.6x",
	     MKWORD(0, mr->fifo_count, 0, nb));
	if (ms->tgts[ms->conn_tgt].data_goes_out)
		nb += mr->fifo_count;
	/* nb is the number of bytes not yet transferred
	   to/from the target. */
	ms->data_ptr -= nb;
	dlog(ms, "data_ptr %x", ms->data_ptr);
	if (ms->data_ptr < 0) {
		printk(KERN_ERR "mesh: halt_dma: data_ptr=%d (nb=%d, ms=%p)\n",
		       ms->data_ptr, nb, ms);
		ms->data_ptr = 0;
#ifdef MESH_DBG
		dumplog(ms, ms->conn_tgt);
		dumpslog(ms);
#endif /* MESH_DBG */
	} else if (cmd && scsi_bufflen(cmd) &&
		   ms->data_ptr > scsi_bufflen(cmd)) {
		printk(KERN_DEBUG "mesh: target %d overrun, "
		       "data_ptr=%x total=%x goes_out=%d\n",
		       ms->conn_tgt, ms->data_ptr, scsi_bufflen(cmd),
		       ms->tgts[ms->conn_tgt].data_goes_out);
	}
	scsi_dma_unmap(cmd);
	ms->dma_started = 0;
}

static void phase_mismatch(struct mesh_state *ms)
{
	volatile struct mesh_regs __iomem *mr = ms->mesh;
	int phase;

	dlog(ms, "phasemm ch/cl/seq/fc=%.8x",
	     MKWORD(mr->count_hi, mr->count_lo, mr->sequence, mr->fifo_count));
	phase = in_8(&mr->bus_status0) & BS0_PHASE;
	if (ms->msgphase == msg_out_xxx && phase == BP_MSGOUT) {
		/* output the last byte of the message, without ATN */
		out_8(&mr->count_lo, 1);
		out_8(&mr->sequence, SEQ_MSGOUT + use_active_neg);
		mesh_flush_io(mr);
		udelay(1);
		out_8(&mr->fifo, ms->msgout[ms->n_msgout-1]);
		ms->msgphase = msg_out_last;
		return;
	}

	if (ms->msgphase == msg_in) {
		get_msgin(ms);
		if (ms->n_msgin)
			handle_msgin(ms);
	}

	if (ms->dma_started)
		halt_dma(ms);
	if (mr->fifo_count) {
		out_8(&mr->sequence, SEQ_FLUSHFIFO);
		mesh_flush_io(mr);
		udelay(1);
	}

	ms->msgphase = msg_none;
	switch (phase) {
	case BP_DATAIN:
		ms->tgts[ms->conn_tgt].data_goes_out = 0;
		ms->phase = dataing;
		break;
	case BP_DATAOUT:
		ms->tgts[ms->conn_tgt].data_goes_out = 1;
		ms->phase = dataing;
		break;
	case BP_COMMAND:
		ms->phase = commanding;
		break;
	case BP_STATUS:
		ms->phase = statusing;
		break;
	case BP_MSGIN:
		ms->msgphase = msg_in;
		ms->n_msgin = 0;
		break;
	case BP_MSGOUT:
		ms->msgphase = msg_out;
		if (ms->n_msgout == 0) {
			if (ms->aborting) {
				do_abort(ms);
			} else {
				if (ms->last_n_msgout == 0) {
					printk(KERN_DEBUG
					       "mesh: no msg to repeat\n");
					ms->msgout[0] = NOP;
					ms->last_n_msgout = 1;
				}
				ms->n_msgout = ms->last_n_msgout;
			}
		}
		break;
	default:
		printk(KERN_DEBUG "mesh: unknown scsi phase %x\n", phase);
		ms->stat = DID_ERROR;
		mesh_done(ms, 1);
		return;
	}

	start_phase(ms);
}

static void cmd_complete(struct mesh_state *ms)
{
	volatile struct mesh_regs __iomem *mr = ms->mesh;
	struct scsi_cmnd *cmd = ms->current_req;
	struct mesh_target *tp = &ms->tgts[ms->conn_tgt];
	int seq, n, t;

	dlog(ms, "cmd_complete fc=%x", mr->fifo_count);
	seq = use_active_neg + (ms->n_msgout? SEQ_ATN: 0);
	switch (ms->msgphase) {
	case msg_out_xxx:
		/* huh?  we expected a phase mismatch */
		ms->n_msgin = 0;
		ms->msgphase = msg_in;
		/* fall through */

	case msg_in:
		/* should have some message bytes in fifo */
		get_msgin(ms);
		n = msgin_length(ms);
		if (ms->n_msgin < n) {
			out_8(&mr->count_lo, n - ms->n_msgin);
			out_8(&mr->sequence, SEQ_MSGIN + seq);
		} else {
			ms->msgphase = msg_none;
			handle_msgin(ms);
			start_phase(ms);
		}
		break;

	case msg_in_bad:
		out_8(&mr->sequence, SEQ_FLUSHFIFO);
		mesh_flush_io(mr);
		udelay(1);
		out_8(&mr->count_lo, 1);
		out_8(&mr->sequence, SEQ_MSGIN + SEQ_ATN + use_active_neg);
		break;

	case msg_out:
		/*
		 * To get the right timing on ATN wrt ACK, we have
		 * to get the MESH to drop ACK, wait until REQ gets
		 * asserted, then drop ATN.  To do this we first
		 * issue a SEQ_MSGOUT with ATN and wait for REQ,
		 * then change the command to a SEQ_MSGOUT w/o ATN.
		 * If we don't see REQ in a reasonable time, we
		 * change the command to SEQ_MSGIN with ATN,
		 * wait for the phase mismatch interrupt, then
		 * issue the SEQ_MSGOUT without ATN.
		 */
		out_8(&mr->count_lo, 1);
		out_8(&mr->sequence, SEQ_MSGOUT + use_active_neg + SEQ_ATN);
		t = 30;		/* wait up to 30us */
		while ((in_8(&mr->bus_status0) & BS0_REQ) == 0 && --t >= 0)
			udelay(1);
		dlog(ms, "last_mbyte err/exc/fc/cl=%.8x",
		     MKWORD(mr->error, mr->exception,
			    mr->fifo_count, mr->count_lo));
		if (in_8(&mr->interrupt) & (INT_ERROR | INT_EXCEPTION)) {
			/* whoops, target didn't do what we expected */
			ms->last_n_msgout = ms->n_msgout;
			ms->n_msgout = 0;
			if (in_8(&mr->interrupt) & INT_ERROR) {
				printk(KERN_ERR "mesh: error %x in msg_out\n",
				       in_8(&mr->error));
				handle_error(ms);
				return;
			}
			if (in_8(&mr->exception) != EXC_PHASEMM)
				printk(KERN_ERR "mesh: exc %x in msg_out\n",
				       in_8(&mr->exception));
			else
				printk(KERN_DEBUG "mesh: bs0=%x in msg_out\n",
				       in_8(&mr->bus_status0));
			handle_exception(ms);
			return;
		}
		if (in_8(&mr->bus_status0) & BS0_REQ) {
			out_8(&mr->sequence, SEQ_MSGOUT + use_active_neg);
			mesh_flush_io(mr);
			udelay(1);
			out_8(&mr->fifo, ms->msgout[ms->n_msgout-1]);
			ms->msgphase = msg_out_last;
		} else {
			out_8(&mr->sequence, SEQ_MSGIN + use_active_neg + SEQ_ATN);
			ms->msgphase = msg_out_xxx;
		}
		break;

	case msg_out_last:
		ms->last_n_msgout = ms->n_msgout;
		ms->n_msgout = 0;
		ms->msgphase = ms->expect_reply? msg_in: msg_none;
		start_phase(ms);
		break;

	case msg_none:
		switch (ms->phase) {
		case idle:
			printk(KERN_ERR "mesh: interrupt in idle phase?\n");
			dumpslog(ms);
			return;
		case selecting:
			dlog(ms, "Selecting phase at command completion",0);
			ms->msgout[0] = IDENTIFY(ALLOW_RESEL(ms->conn_tgt),
						 (cmd? cmd->device->lun: 0));
			ms->n_msgout = 1;
			ms->expect_reply = 0;
			if (ms->aborting) {
				ms->msgout[0] = ABORT;
				ms->n_msgout++;
			} else if (tp->sdtr_state == do_sdtr) {
				/* add SDTR message */
				add_sdtr_msg(ms);
				ms->expect_reply = 1;
				tp->sdtr_state = sdtr_sent;