patch-2.4.13 linux/drivers/message/i2o/i2o_scsi.c

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diff -u --recursive --new-file v2.4.12/linux/drivers/message/i2o/i2o_scsi.c linux/drivers/message/i2o/i2o_scsi.c
@@ -0,0 +1,923 @@
+/* 
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2, or (at your option) any
+ *  later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but
+ *  WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  General Public License for more details.
+ *
+ *  Complications for I2O scsi
+ *
+ *	o	Each (bus,lun) is a logical device in I2O. We keep a map
+ *		table. We spoof failed selection for unmapped units
+ *	o	Request sense buffers can come back for free. 
+ *	o	Scatter gather is a bit dynamic. We have to investigate at
+ *		setup time.
+ *	o	Some of our resources are dynamically shared. The i2o core
+ *		needs a message reservation protocol to avoid swap v net
+ *		deadlocking. We need to back off queue requests.
+ *	
+ *	In general the firmware wants to help. Where its help isn't performance
+ *	useful we just ignore the aid. Its not worth the code in truth.
+ *
+ *	Fixes:
+ *		Steve Ralston	:	Scatter gather now works
+ *
+ *	To Do
+ *		64bit cleanups
+ *		Fix the resource management problems.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/ioport.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/timer.h>
+#include <linux/delay.h>
+#include <linux/proc_fs.h>
+#include <linux/prefetch.h>
+#include <asm/dma.h>
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/atomic.h>
+#include <linux/blk.h>
+#include <linux/version.h>
+#include <linux/i2o.h>
+#include "../../scsi/scsi.h"
+#include "../../scsi/hosts.h"
+#include "../../scsi/sd.h"
+#include "i2o_scsi.h"
+
+#define VERSION_STRING        "Version 0.0.1"
+
+#define dprintk(x)
+
+#define MAXHOSTS 32
+
+struct i2o_scsi_host
+{
+	struct i2o_controller *controller;
+	s16 task[16][8];		/* Allow 16 devices for now */
+	unsigned long tagclock[16][8];	/* Tag clock for queueing */
+	s16 bus_task;		/* The adapter TID */
+};
+
+static int scsi_context;
+static int lun_done;
+static int i2o_scsi_hosts;
+
+static u32 *retry[32];
+static struct i2o_controller *retry_ctrl[32];
+static struct timer_list retry_timer;
+static int retry_ct = 0;
+
+static atomic_t queue_depth;
+
+/*
+ *	SG Chain buffer support...
+ */
+
+#define SG_MAX_FRAGS		64
+
+/*
+ *	FIXME: we should allocate one of these per bus we find as we
+ *	locate them not in a lump at boot.
+ */
+ 
+typedef struct _chain_buf
+{
+	u32 sg_flags_cnt[SG_MAX_FRAGS];
+	u32 sg_buf[SG_MAX_FRAGS];
+} chain_buf;
+
+#define SG_CHAIN_BUF_SZ sizeof(chain_buf)
+
+#define SG_MAX_BUFS		(i2o_num_controllers * I2O_SCSI_CAN_QUEUE)
+#define SG_CHAIN_POOL_SZ	(SG_MAX_BUFS * SG_CHAIN_BUF_SZ)
+
+static int max_sg_len = 0;
+static chain_buf *sg_chain_pool = NULL;
+static int sg_chain_tag = 0;
+static int sg_max_frags = SG_MAX_FRAGS;
+
+/*
+ *	Retry congested frames. This actually needs pushing down into
+ *	i2o core. We should only bother the OSM with this when we can't
+ *	queue and retry the frame. Or perhaps we should call the OSM
+ *	and its default handler should be this in the core, and this
+ *	call a 2nd "I give up" handler in the OSM ?
+ */
+ 
+static void i2o_retry_run(unsigned long f)
+{
+	int i;
+	unsigned long flags;
+	
+	save_flags(flags);
+	cli();
+
+	for(i=0;i<retry_ct;i++)
+		i2o_post_message(retry_ctrl[i], virt_to_bus(retry[i]));
+	retry_ct=0;
+	
+	restore_flags(flags);
+}
+
+static void flush_pending(void)
+{
+	int i;
+	unsigned long flags;
+	
+	save_flags(flags);
+	cli();
+
+	for(i=0;i<retry_ct;i++)
+	{
+		retry[i][0]&=~0xFFFFFF;
+		retry[i][0]|=I2O_CMD_UTIL_NOP<<24;
+		i2o_post_message(retry_ctrl[i],virt_to_bus(retry[i]));
+	}
+	retry_ct=0;
+	
+	restore_flags(flags);
+}
+
+static void i2o_scsi_reply(struct i2o_handler *h, struct i2o_controller *c, struct i2o_message *msg)
+{
+	Scsi_Cmnd *current_command;
+	u32 *m = (u32 *)msg;
+	u8 as,ds,st;
+
+	spin_lock_prefetch(&io_request_lock);		
+
+	if(m[0] & (1<<13))
+	{
+		printk("IOP fail.\n");
+		printk("From %d To %d Cmd %d.\n",
+			(m[1]>>12)&0xFFF,
+			m[1]&0xFFF,
+			m[1]>>24);
+		printk("Failure Code %d.\n", m[4]>>24);
+		if(m[4]&(1<<16))
+			printk("Format error.\n");
+		if(m[4]&(1<<17))
+			printk("Path error.\n");
+		if(m[4]&(1<<18))
+			printk("Path State.\n");
+		if(m[4]&(1<<18))
+			printk("Congestion.\n");
+		
+		m=(u32 *)bus_to_virt(m[7]);
+		printk("Failing message is %p.\n", m);
+		
+		if((m[4]&(1<<18)) && retry_ct < 32)
+		{
+			retry_ctrl[retry_ct]=c;
+			retry[retry_ct]=m;
+			if(!retry_ct++)
+			{
+				retry_timer.expires=jiffies+1;
+				add_timer(&retry_timer);
+			}
+		}
+		else
+		{
+			/* Create a scsi error for this */
+			current_command = (Scsi_Cmnd *)m[3];
+			printk("Aborted %ld\n", current_command->serial_number);
+
+			spin_lock_irq(&io_request_lock);			
+			current_command->result = DID_ERROR << 16;
+			current_command->scsi_done(current_command);
+			spin_unlock_irq(&io_request_lock);			
+			
+			/* Now flush the message by making it a NOP */
+			m[0]&=0x00FFFFFF;
+			m[0]|=(I2O_CMD_UTIL_NOP)<<24;
+			i2o_post_message(c,virt_to_bus(m));
+		}
+		return;
+	}
+	
+	prefetchw(&queue_depth);
+		
+	
+	/*
+	 *	Low byte is device status, next is adapter status,
+	 *	(then one byte reserved), then request status.
+	 */
+	ds=(u8)m[4]; 
+	as=(u8)(m[4]>>8);
+	st=(u8)(m[4]>>24);
+	
+	dprintk(("i2o got a scsi reply %08X: ", m[0]));
+	dprintk(("m[2]=%08X: ", m[2]));
+	dprintk(("m[4]=%08X\n", m[4]));
+
+	if(m[2]&0x80000000)
+	{
+		if(m[2]&0x40000000)
+		{
+			dprintk(("Event.\n"));
+			lun_done=1;
+			return;
+		}
+		printk(KERN_ERR "i2o_scsi: bus reset reply.\n");
+		return;
+	}
+	
+	current_command = (Scsi_Cmnd *)m[3];
+	
+	/*
+	 *	Is this a control request coming back - eg an abort ?
+	 */
+	 
+	if(current_command==NULL)
+	{
+		if(st)
+			dprintk(("SCSI abort: %08X", m[4]));
+		dprintk(("SCSI abort completed.\n"));
+		return;
+	}
+	
+	dprintk(("Completed %ld\n", current_command->serial_number));
+	
+	atomic_dec(&queue_depth);
+	
+	if(st == 0x06)
+	{
+		if(m[5] < current_command->underflow)
+		{
+			int i;
+			printk(KERN_ERR "SCSI: underflow 0x%08X 0x%08X\n",
+				m[5], current_command->underflow);
+			printk("Cmd: ");
+			for(i=0;i<15;i++)
+				printk("%02X ", current_command->cmnd[i]);
+			printk(".\n");
+		}
+		else st=0;
+	}
+	
+	if(st)
+	{
+		/* An error has occurred */
+
+		dprintk((KERN_DEBUG "SCSI error %08X", m[4]));
+			
+		if (as == 0x0E) 
+			/* SCSI Reset */
+			current_command->result = DID_RESET << 16;
+		else if (as == 0x0F)
+			current_command->result = DID_PARITY << 16;
+		else
+			current_command->result = DID_ERROR << 16;
+	}
+	else
+		/*
+		 *	It worked maybe ?
+		 */		
+		current_command->result = DID_OK << 16 | ds;
+	spin_lock(&io_request_lock);
+	current_command->scsi_done(current_command);
+	spin_unlock(&io_request_lock);
+	return;
+}
+
+struct i2o_handler i2o_scsi_handler=
+{
+	i2o_scsi_reply,
+	NULL,
+	NULL,
+	NULL,
+	"I2O SCSI OSM",
+	0,
+	I2O_CLASS_SCSI_PERIPHERAL
+};
+
+static int i2o_find_lun(struct i2o_controller *c, struct i2o_device *d, int *target, int *lun)
+{
+	u8 reply[8];
+	
+	if(i2o_query_scalar(c, d->lct_data.tid, 0, 3, reply, 4)<0)
+		return -1;
+		
+	*target=reply[0];
+	
+	if(i2o_query_scalar(c, d->lct_data.tid, 0, 4, reply, 8)<0)
+		return -1;
+
+	*lun=reply[1];
+
+	dprintk(("SCSI (%d,%d)\n", *target, *lun));
+	return 0;
+}
+
+void i2o_scsi_init(struct i2o_controller *c, struct i2o_device *d, struct Scsi_Host *shpnt)
+{
+	struct i2o_device *unit;
+	struct i2o_scsi_host *h =(struct i2o_scsi_host *)shpnt->hostdata;
+	int lun;
+	int target;
+	
+	h->controller=c;
+	h->bus_task=d->lct_data.tid;
+	
+	for(target=0;target<16;target++)
+		for(lun=0;lun<8;lun++)
+			h->task[target][lun] = -1;
+			
+	for(unit=c->devices;unit!=NULL;unit=unit->next)
+	{
+		dprintk(("Class %03X, parent %d, want %d.\n",
+			unit->lct_data.class_id, unit->lct_data.parent_tid, d->lct_data.tid));
+			
+		/* Only look at scsi and fc devices */
+		if (    (unit->lct_data.class_id != I2O_CLASS_SCSI_PERIPHERAL)
+		     && (unit->lct_data.class_id != I2O_CLASS_FIBRE_CHANNEL_PERIPHERAL)
+		   )
+			continue;
+
+		/* On our bus ? */
+		dprintk(("Found a disk (%d).\n", unit->lct_data.tid));
+		if ((unit->lct_data.parent_tid == d->lct_data.tid)
+		     || (unit->lct_data.parent_tid == d->lct_data.parent_tid)
+		   )
+		{
+			u16 limit;
+			dprintk(("Its ours.\n"));
+			if(i2o_find_lun(c, unit, &target, &lun)==-1)
+			{
+				printk(KERN_ERR "i2o_scsi: Unable to get lun for tid %d.\n", unit->lct_data.tid);
+				continue;
+			}
+			dprintk(("Found disk %d %d.\n", target, lun));
+			h->task[target][lun]=unit->lct_data.tid;
+			h->tagclock[target][lun]=jiffies;
+
+			/* Get the max fragments/request */
+			i2o_query_scalar(c, d->lct_data.tid, 0xF103, 3, &limit, 2);
+			
+			/* sanity */
+			if ( limit == 0 )
+			{
+				printk(KERN_WARNING "i2o_scsi: Ignoring unreasonable SG limit of 0 from IOP!\n");
+				limit = 1;
+			}
+			
+			shpnt->sg_tablesize = limit;
+
+			dprintk(("i2o_scsi: set scatter-gather to %d.\n", 
+				shpnt->sg_tablesize));
+		}
+	}		
+}
+
+int i2o_scsi_detect(Scsi_Host_Template * tpnt)
+{
+	unsigned long flags;
+	struct Scsi_Host *shpnt = NULL;
+	int i;
+	int count;
+
+	printk("i2o_scsi.c: %s\n", VERSION_STRING);
+
+	if(i2o_install_handler(&i2o_scsi_handler)<0)
+	{
+		printk(KERN_ERR "i2o_scsi: Unable to install OSM handler.\n");
+		return 0;
+	}
+	scsi_context = i2o_scsi_handler.context;
+	
+	if((sg_chain_pool = kmalloc(SG_CHAIN_POOL_SZ, GFP_KERNEL)) == NULL)
+	{
+		printk("i2o_scsi: Unable to alloc %d byte SG chain buffer pool.\n", SG_CHAIN_POOL_SZ);
+		printk("i2o_scsi: SG chaining DISABLED!\n");
+		sg_max_frags = 11;
+	}
+	else
+	{
+		printk("  chain_pool: %d bytes @ %p\n", SG_CHAIN_POOL_SZ, sg_chain_pool);
+		printk("  (%d byte buffers X %d can_queue X %d i2o controllers)\n",
+				SG_CHAIN_BUF_SZ, I2O_SCSI_CAN_QUEUE, i2o_num_controllers);
+		sg_max_frags = SG_MAX_FRAGS;    // 64
+	}
+	
+	init_timer(&retry_timer);
+	retry_timer.data = 0UL;
+	retry_timer.function = i2o_retry_run;
+	
+//	printk("SCSI OSM at %d.\n", scsi_context);
+
+	for (count = 0, i = 0; i < MAX_I2O_CONTROLLERS; i++)
+	{
+		struct i2o_controller *c=i2o_find_controller(i);
+		struct i2o_device *d;
+		/*
+		 *	This controller doesn't exist.
+		 */
+		
+		if(c==NULL)
+			continue;
+			
+		/*
+		 *	Fixme - we need some altered device locking. This
+		 *	is racing with device addition in theory. Easy to fix.
+		 */
+		
+		for(d=c->devices;d!=NULL;d=d->next)
+		{
+			/*
+			 *	bus_adapter, SCSI (obsolete), or FibreChannel busses only
+			 */
+			if(    (d->lct_data.class_id!=I2O_CLASS_BUS_ADAPTER_PORT)	// bus_adapter
+//			    && (d->lct_data.class_id!=I2O_CLASS_FIBRE_CHANNEL_PORT)	// FC_PORT
+			  )
+				continue;
+		
+			shpnt = scsi_register(tpnt, sizeof(struct i2o_scsi_host));
+			if(shpnt==NULL)
+				continue;
+			save_flags(flags);
+			cli();
+			shpnt->unique_id = (u32)d;
+			shpnt->io_port = 0;
+			shpnt->n_io_port = 0;
+			shpnt->irq = 0;
+			shpnt->this_id = /* Good question */15;
+			restore_flags(flags);
+			i2o_scsi_init(c, d, shpnt);
+			count++;
+		}
+	}
+	i2o_scsi_hosts = count;
+	
+	if(count==0)
+	{
+		if(sg_chain_pool!=NULL)
+		{
+			kfree(sg_chain_pool);
+			sg_chain_pool = NULL;
+		}
+		flush_pending();
+		del_timer(&retry_timer);
+		i2o_remove_handler(&i2o_scsi_handler);
+	}
+	
+	return count;
+}
+
+int i2o_scsi_release(struct Scsi_Host *host)
+{
+	if(--i2o_scsi_hosts==0)
+	{
+		if(sg_chain_pool!=NULL)
+		{
+			kfree(sg_chain_pool);
+			sg_chain_pool = NULL;
+		}
+		flush_pending();
+		del_timer(&retry_timer);
+		i2o_remove_handler(&i2o_scsi_handler);
+	}
+	return 0;
+}
+
+
+const char *i2o_scsi_info(struct Scsi_Host *SChost)
+{
+	struct i2o_scsi_host *hostdata;
+
+	hostdata = (struct i2o_scsi_host *)SChost->hostdata;
+
+	return(&hostdata->controller->name[0]);
+}
+
+
+/*
+ * From the wd93 driver:
+ * Returns true if there will be a DATA_OUT phase with this command, 
+ * false otherwise.
+ * (Thanks to Joerg Dorchain for the research and suggestion.)
+ *
+ */
+static int is_dir_out(Scsi_Cmnd *cmd)
+{
+	switch (cmd->cmnd[0]) 
+	{
+     		case WRITE_6:           case WRITE_10:          case WRITE_12:
+      		case WRITE_LONG:        case WRITE_SAME:        case WRITE_BUFFER:
+      		case WRITE_VERIFY:      case WRITE_VERIFY_12:      
+      		case COMPARE:           case COPY:              case COPY_VERIFY:
+      		case SEARCH_EQUAL:      case SEARCH_HIGH:       case SEARCH_LOW:
+      		case SEARCH_EQUAL_12:   case SEARCH_HIGH_12:    case SEARCH_LOW_12:      
+      		case FORMAT_UNIT:       case REASSIGN_BLOCKS:   case RESERVE:
+      		case MODE_SELECT:       case MODE_SELECT_10:    case LOG_SELECT:
+      		case SEND_DIAGNOSTIC:   case CHANGE_DEFINITION: case UPDATE_BLOCK:
+      		case SET_WINDOW:        case MEDIUM_SCAN:       case SEND_VOLUME_TAG:
+      		case 0xea:
+        		return 1;
+		default:
+        		return 0;
+	}
+}
+
+int i2o_scsi_queuecommand(Scsi_Cmnd * SCpnt, void (*done) (Scsi_Cmnd *))
+{
+	int i;
+	int tid;
+	struct i2o_controller *c;
+	Scsi_Cmnd *current_command;
+	struct Scsi_Host *host;
+	struct i2o_scsi_host *hostdata;
+	u32 *msg, *mptr;
+	u32 m;
+	u32 *lenptr;
+	int direction;
+	int scsidir;
+	u32 len;
+	u32 reqlen;
+	u32 tag;
+	
+	static int max_qd = 1;
+	
+	/*
+	 *	Do the incoming paperwork
+	 */
+	 
+	host = SCpnt->host;
+	hostdata = (struct i2o_scsi_host *)host->hostdata;
+	 
+	c = hostdata->controller;
+	prefetch(c);
+	prefetchw(&queue_depth);
+
+	SCpnt->scsi_done = done;
+	
+	if(SCpnt->target > 15)
+	{
+		printk(KERN_ERR "i2o_scsi: Wild target %d.\n", SCpnt->target);
+		return -1;
+	}
+	
+	tid = hostdata->task[SCpnt->target][SCpnt->lun];
+	
+	dprintk(("qcmd: Tid = %d\n", tid));
+	
+	current_command = SCpnt;		/* set current command                */
+	current_command->scsi_done = done;	/* set ptr to done function           */
+
+	/* We don't have such a device. Pretend we did the command 
+	   and that selection timed out */
+	
+	if(tid == -1)
+	{
+		SCpnt->result = DID_NO_CONNECT << 16;
+		done(SCpnt);
+		return 0;
+	}
+	
+	dprintk(("Real scsi messages.\n"));
+
+	
+	/*
+	 *	Obtain an I2O message. Right now we _have_ to obtain one
+	 *	until the scsi layer stuff is cleaned up.
+	 */	
+	 
+	do
+	{
+		mb();
+		m = I2O_POST_READ32(c);
+	}
+	while(m==0xFFFFFFFF);
+	msg = (u32 *)(c->mem_offset + m);
+	
+	/*
+	 *	Put together a scsi execscb message
+	 */
+	
+	len = SCpnt->request_bufflen;
+	direction = 0x00000000;			// SGL IN  (osm<--iop)
+	
+	/*
+	 *	The scsi layer should be handling this stuff
+	 */
+	
+	scsidir = 0x00000000;			// DATA NO XFER
+	if(len)
+	{
+		if(is_dir_out(SCpnt))
+		{
+			direction=0x04000000;	// SGL OUT  (osm-->iop)
+			scsidir  =0x80000000;	// DATA OUT (iop-->dev)
+		}
+		else
+		{
+			scsidir  =0x40000000;	// DATA IN  (iop<--dev)
+		}
+	}
+	
+	__raw_writel(I2O_CMD_SCSI_EXEC<<24|HOST_TID<<12|tid, &msg[1]);
+	__raw_writel(scsi_context, &msg[2]);	/* So the I2O layer passes to us */
+	/* Sorry 64bit folks. FIXME */
+	__raw_writel((u32)SCpnt, &msg[3]);	/* We want the SCSI control block back */
+
+	/* LSI_920_PCI_QUIRK
+	 *
+	 *	Intermittant observations of msg frame word data corruption
+	 *	observed on msg[4] after:
+	 *	  WRITE, READ-MODIFY-WRITE
+	 *	operations.  19990606 -sralston
+	 *
+	 *	(Hence we build this word via tag. Its good practice anyway
+	 *	 we don't want fetches over PCI needlessly)
+	 */
+
+	tag=0;
+	
+	/*
+	 *	Attach tags to the devices
+	 */	
+	if(SCpnt->device->tagged_supported)
+	{
+		/*
+		 *	Some drives are too stupid to handle fairness issues
+		 *	with tagged queueing. We throw in the odd ordered
+		 *	tag to stop them starving themselves.
+		 */
+		if((jiffies - hostdata->tagclock[SCpnt->target][SCpnt->lun]) > (5*HZ))
+		{
+			tag=0x01800000;		/* ORDERED! */
+			hostdata->tagclock[SCpnt->target][SCpnt->lun]=jiffies;
+		}
+		else
+		{
+			/* Hmmm...  I always see value of 0 here,
+			 *  of which {HEAD_OF, ORDERED, SIMPLE} are NOT!  -sralston
+			 */
+			if(SCpnt->tag == HEAD_OF_QUEUE_TAG)
+				tag=0x01000000;
+			else if(SCpnt->tag == ORDERED_QUEUE_TAG)
+				tag=0x01800000;
+		}
+	}
+
+	/* Direction, disconnect ok, tag, CDBLen */
+	__raw_writel(scsidir|0x20000000|SCpnt->cmd_len|tag, &msg[4]);
+
+	mptr=msg+5;
+
+	/* 
+	 *	Write SCSI command into the message - always 16 byte block 
+	 */
+	 
+	memcpy_toio(mptr, SCpnt->cmnd, 16);
+	mptr+=4;
+	lenptr=mptr++;		/* Remember me - fill in when we know */
+	
+	reqlen = 12;		// SINGLE SGE
+	
+	/*
+	 *	Now fill in the SGList and command 
+	 *
+	 *	FIXME: we need to set the sglist limits according to the 
+	 *	message size of the I2O controller. We might only have room
+	 *	for 6 or so worst case
+	 */
+	
+	if(SCpnt->use_sg)
+	{
+		struct scatterlist *sg = (struct scatterlist *)SCpnt->request_buffer;
+		int chain = 0;
+		
+		len = 0;
+
+		if((sg_max_frags > 11) && (SCpnt->use_sg > 11))
+		{
+			chain = 1;
+			/*
+			 *	Need to chain!
+			 */
+			__raw_writel(direction|0xB0000000|(SCpnt->use_sg*2*4), mptr++);
+			__raw_writel(virt_to_bus(sg_chain_pool + sg_chain_tag), mptr);
+			mptr = (u32*)(sg_chain_pool + sg_chain_tag);
+			if (SCpnt->use_sg > max_sg_len)
+			{
+				max_sg_len = SCpnt->use_sg;
+				printk("i2o_scsi: Chain SG! SCpnt=%p, SG_FragCnt=%d, SG_idx=%d\n",
+					SCpnt, SCpnt->use_sg, sg_chain_tag);
+			}
+			if ( ++sg_chain_tag == SG_MAX_BUFS )
+				sg_chain_tag = 0;
+			for(i = 0 ; i < SCpnt->use_sg; i++)
+			{
+				*mptr++=direction|0x10000000|sg->length;
+				len+=sg->length;
+				*mptr++=virt_to_bus(sg->address);
+				sg++;
+			}
+			mptr[-2]=direction|0xD0000000|(sg-1)->length;
+		}
+		else
+		{		
+			for(i = 0 ; i < SCpnt->use_sg; i++)
+			{
+				__raw_writel(direction|0x10000000|sg->length, mptr++);
+				len+=sg->length;
+				__raw_writel(virt_to_bus(sg->address), mptr++);
+				sg++;
+			}
+
+			/* Make this an end of list. Again evade the 920 bug and
+			   unwanted PCI read traffic */
+		
+			__raw_writel(direction|0xD0000000|(sg-1)->length, &mptr[-2]);
+		}
+		
+		if(!chain)
+			reqlen = mptr - msg;
+		
+		__raw_writel(len, lenptr);
+		
+		if(len != SCpnt->underflow)
+			printk("Cmd len %08X Cmd underflow %08X\n",
+				len, SCpnt->underflow);
+	}
+	else
+	{
+		dprintk(("non sg for %p, %d\n", SCpnt->request_buffer,
+				SCpnt->request_bufflen));
+		__raw_writel(len = SCpnt->request_bufflen, lenptr);
+		if(len == 0)
+		{
+			reqlen = 9;
+		}
+		else
+		{
+			__raw_writel(0xD0000000|direction|SCpnt->request_bufflen, mptr++);
+			__raw_writel(virt_to_bus(SCpnt->request_buffer), mptr++);
+		}
+	}
+	
+	/*
+	 *	Stick the headers on 
+	 */
+
+	__raw_writel(reqlen<<16 | SGL_OFFSET_10, msg);
+	
+	/* Queue the message */
+	i2o_post_message(c,m);
+	
+	atomic_inc(&queue_depth);
+	
+	if(atomic_read(&queue_depth)> max_qd)
+	{
+		max_qd=atomic_read(&queue_depth);
+		printk("Queue depth now %d.\n", max_qd);
+	}
+	
+	mb();
+	dprintk(("Issued %ld\n", current_command->serial_number));
+	
+	return 0;
+}
+
+static void internal_done(Scsi_Cmnd * SCpnt)
+{
+	SCpnt->SCp.Status++;
+}
+
+int i2o_scsi_command(Scsi_Cmnd * SCpnt)
+{
+	i2o_scsi_queuecommand(SCpnt, internal_done);
+	SCpnt->SCp.Status = 0;
+	while (!SCpnt->SCp.Status)
+		barrier();
+	return SCpnt->result;
+}
+
+int i2o_scsi_abort(Scsi_Cmnd * SCpnt)
+{
+	struct i2o_controller *c;
+	struct Scsi_Host *host;
+	struct i2o_scsi_host *hostdata;
+	u32 *msg;
+	u32 m;
+	int tid;
+	
+	printk("i2o_scsi: Aborting command block.\n");
+	
+	host = SCpnt->host;
+	hostdata = (struct i2o_scsi_host *)host->hostdata;
+	tid = hostdata->task[SCpnt->target][SCpnt->lun];
+	if(tid==-1)
+	{
+		printk(KERN_ERR "impossible command to abort.\n");
+		return SCSI_ABORT_NOT_RUNNING;
+	}
+	c = hostdata->controller;
+	
+	/*
+	 *	Obtain an I2O message. Right now we _have_ to obtain one
+	 *	until the scsi layer stuff is cleaned up.
+	 */	
+	 
+	do
+	{
+		mb();
+		m = I2O_POST_READ32(c);
+	}
+	while(m==0xFFFFFFFF);
+	msg = (u32 *)(c->mem_offset + m);
+	
+	__raw_writel(FIVE_WORD_MSG_SIZE, &msg[0]);
+	__raw_writel(I2O_CMD_SCSI_ABORT<<24|HOST_TID<<12|tid, &msg[1]);
+	__raw_writel(scsi_context, &msg[2]);
+	__raw_writel(0, &msg[3]);	/* Not needed for an abort */
+	__raw_writel((u32)SCpnt, &msg[4]);	
+	wmb();
+	i2o_post_message(c,m);
+	wmb();
+	return SCSI_ABORT_PENDING;
+}
+
+int i2o_scsi_reset(Scsi_Cmnd * SCpnt, unsigned int reset_flags)
+{
+	int tid;
+	struct i2o_controller *c;
+	struct Scsi_Host *host;
+	struct i2o_scsi_host *hostdata;
+	u32 m;
+	u32 *msg;
+
+	/*
+	 *	Find the TID for the bus
+	 */
+
+	printk("i2o_scsi: Attempting to reset the bus.\n");
+	
+	host = SCpnt->host;
+	hostdata = (struct i2o_scsi_host *)host->hostdata;
+	tid = hostdata->bus_task;
+	c = hostdata->controller;
+
+	/*
+	 *	Now send a SCSI reset request. Any remaining commands
+	 *	will be aborted by the IOP. We need to catch the reply
+	 *	possibly ?
+	 */
+	 
+	m = I2O_POST_READ32(c);
+	
+	/*
+	 *	No free messages, try again next time - no big deal
+	 */
+	 
+	if(m == 0xFFFFFFFF)
+		return SCSI_RESET_PUNT;
+	
+	msg = (u32 *)(c->mem_offset + m);
+	__raw_writel(FOUR_WORD_MSG_SIZE|SGL_OFFSET_0, &msg[0]);
+	__raw_writel(I2O_CMD_SCSI_BUSRESET<<24|HOST_TID<<12|tid, &msg[1]);
+	__raw_writel(scsi_context|0x80000000, &msg[2]);
+	/* We use the top bit to split controller and unit transactions */
+	/* Now store unit,tid so we can tie the completion back to a specific device */
+	__raw_writel(c->unit << 16 | tid, &msg[3]);
+	wmb();
+	i2o_post_message(c,m);
+	return SCSI_RESET_PENDING;
+}
+
+/*
+ *	This is anyones guess quite frankly.
+ */
+ 
+int i2o_scsi_bios_param(Disk * disk, kdev_t dev, int *ip)
+{
+	int size;
+
+	size = disk->capacity;
+	ip[0] = 64;		/* heads                        */
+	ip[1] = 32;		/* sectors                      */
+	if ((ip[2] = size >> 11) > 1024) {	/* cylinders, test for big disk */
+		ip[0] = 255;	/* heads                        */
+		ip[1] = 63;	/* sectors                      */
+		ip[2] = size / (255 * 63);	/* cylinders                    */
+	}
+	return 0;
+}
+
+MODULE_AUTHOR("Red Hat Software");
+MODULE_LICENSE("GPL");
+
+
+static Scsi_Host_Template driver_template = I2OSCSI;
+
+#include "../../scsi/scsi_module.c"
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TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)