include upstream ip1000a driver version 2.09f

[linux-2.4.git] / drivers / message / i2o / i2o_block.c

/*
 * I2O Random Block Storage Class OSM
 *
 * (C) Copyright 1999 Red Hat Software
 *      
 * Written by Alan Cox, Building Number Three Ltd
 *
 * 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 of the License, or (at your option) any later version.
 *
 * This is a beta test release. Most of the good code was taken
 * from the nbd driver by Pavel Machek, who in turn took some of it
 * from loop.c. Isn't free software great for reusability 8)
 *
 * Fixes/additions:
 *      Steve Ralston:  
 *              Multiple device handling error fixes,
 *              Added a queue depth.
 *      Alan Cox:       
 *              FC920 has an rmw bug. Dont or in the end marker.
 *              Removed queue walk, fixed for 64bitness.
 *              Rewrote much of the code over time
 *              Added indirect block lists
 *              Handle 64K limits on many controllers
 *              Don't use indirects on the Promise (breaks)
 *              Heavily chop down the queue depths
 *      Deepak Saxena:
 *              Independent queues per IOP
 *              Support for dynamic device creation/deletion
 *              Code cleanup    
 *              Support for larger I/Os through merge* functions 
 *              (taken from DAC960 driver)
 *      Boji T Kannanthanam:
 *              Set the I2O Block devices to be detected in increasing 
 *              order of TIDs during boot.
 *              Search and set the I2O block device that we boot off from  as
 *              the first device to be claimed (as /dev/i2o/hda)
 *              Properly attach/detach I2O gendisk structure from the system
 *              gendisk list. The I2O block devices now appear in 
 *              /proc/partitions.
 *
 *      To do:
 *              Serial number scanning to find duplicates for FC multipathing
 */

#include <linux/major.h>

#include <linux/module.h>

#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/pci.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/ioctl.h>
#include <linux/i2o.h>
#include <linux/blkdev.h>
#include <linux/blkpg.h>
#include <linux/slab.h>
#include <linux/hdreg.h>
#include <linux/spinlock.h>

#include <linux/notifier.h>
#include <linux/reboot.h>

#include <asm/uaccess.h>
#include <asm/semaphore.h>
#include <linux/completion.h>
#include <asm/io.h>
#include <asm/atomic.h>
#include <linux/smp_lock.h>
#include <linux/wait.h>

#define MAJOR_NR I2O_MAJOR

#include <linux/blk.h>

#define MAX_I2OB        16

#define MAX_I2OB_DEPTH  8
#define MAX_I2OB_RETRIES 4

//#define DRIVERDEBUG
#ifdef DRIVERDEBUG
#define DEBUG( s ) printk( s )
#else
#define DEBUG( s )
#endif

/*
 * Events that this OSM is interested in
 */
#define I2OB_EVENT_MASK         (I2O_EVT_IND_BSA_VOLUME_LOAD |  \
                                 I2O_EVT_IND_BSA_VOLUME_UNLOAD | \
                                 I2O_EVT_IND_BSA_VOLUME_UNLOAD_REQ | \
                                 I2O_EVT_IND_BSA_CAPACITY_CHANGE | \
                                 I2O_EVT_IND_BSA_SCSI_SMART )


/*
 * I2O Block Error Codes - should be in a header file really...
 */
#define I2O_BSA_DSC_SUCCESS             0x0000
#define I2O_BSA_DSC_MEDIA_ERROR         0x0001
#define I2O_BSA_DSC_ACCESS_ERROR        0x0002
#define I2O_BSA_DSC_DEVICE_FAILURE      0x0003
#define I2O_BSA_DSC_DEVICE_NOT_READY    0x0004
#define I2O_BSA_DSC_MEDIA_NOT_PRESENT   0x0005
#define I2O_BSA_DSC_MEDIA_LOCKED        0x0006
#define I2O_BSA_DSC_MEDIA_FAILURE       0x0007
#define I2O_BSA_DSC_PROTOCOL_FAILURE    0x0008
#define I2O_BSA_DSC_BUS_FAILURE         0x0009
#define I2O_BSA_DSC_ACCESS_VIOLATION    0x000A
#define I2O_BSA_DSC_WRITE_PROTECTED     0x000B
#define I2O_BSA_DSC_DEVICE_RESET        0x000C
#define I2O_BSA_DSC_VOLUME_CHANGED      0x000D
#define I2O_BSA_DSC_TIMEOUT             0x000E

/*
 *      Some of these can be made smaller later
 */

static int i2ob_blksizes[MAX_I2OB<<4];
static int i2ob_hardsizes[MAX_I2OB<<4];
static int i2ob_sizes[MAX_I2OB<<4];
static int i2ob_media_change_flag[MAX_I2OB];
static u32 i2ob_max_sectors[MAX_I2OB<<4];

static int i2ob_context;

/*
 * I2O Block device descriptor 
 */
struct i2ob_device
{
        struct i2o_controller *controller;
        struct i2o_device *i2odev;
        int unit;
        int tid;
        int flags;
        int refcnt;
        struct request *head, *tail;
        request_queue_t *req_queue;
        int max_segments;
        int max_direct;         /* Not yet used properly */
        int done_flag;
        int depth;
        int rcache;
        int wcache;
        int power;
};

/*
 *      FIXME:
 *      We should cache align these to avoid ping-ponging lines on SMP
 *      boxes under heavy I/O load...
 */

struct i2ob_request
{
        struct i2ob_request *next;
        struct request *req;
        int num;
};

/*
 * Per IOP requst queue information
 *
 * We have a separate requeust_queue_t per IOP so that a heavilly
 * loaded I2O block device on an IOP does not starve block devices
 * across all I2O controllers.
 * 
 */
struct i2ob_iop_queue
{
        atomic_t queue_depth;
        struct i2ob_request request_queue[MAX_I2OB_DEPTH];
        struct i2ob_request *i2ob_qhead;
        request_queue_t req_queue;
};
static struct i2ob_iop_queue *i2ob_queues[MAX_I2O_CONTROLLERS];

/*
 *      Each I2O disk is one of these.
 */

static struct i2ob_device i2ob_dev[MAX_I2OB<<4];
static int i2ob_dev_count = 0;
static struct hd_struct i2ob[MAX_I2OB<<4];
static struct gendisk i2ob_gendisk;     /* Declared later */

/*
 * Mutex and spin lock for event handling synchronization
 * evt_msg contains the last event.
 */
static DECLARE_MUTEX_LOCKED(i2ob_evt_sem);
static DECLARE_COMPLETION(i2ob_thread_dead);
static spinlock_t i2ob_evt_lock = SPIN_LOCK_UNLOCKED;
static u32 evt_msg[MSG_FRAME_SIZE];

static void i2o_block_reply(struct i2o_handler *, struct i2o_controller *,
         struct i2o_message *);
static void i2ob_new_device(struct i2o_controller *, struct i2o_device *);
static void i2ob_del_device(struct i2o_controller *, struct i2o_device *);
static void i2ob_reboot_event(void);
static int i2ob_install_device(struct i2o_controller *, struct i2o_device *, int);
static void i2ob_end_request(struct request *);
static void i2ob_request(request_queue_t *);
static int i2ob_init_iop(unsigned int);
static request_queue_t* i2ob_get_queue(kdev_t);
static int i2ob_query_device(struct i2ob_device *, int, int, void*, int);
static int do_i2ob_revalidate(kdev_t, int);
static int i2ob_evt(void *);

static int evt_pid = 0;
static int evt_running = 0;
static int scan_unit = 0;

/*
 * I2O OSM registration structure...keeps getting bigger and bigger :)
 */
static struct i2o_handler i2o_block_handler =
{
        i2o_block_reply,
        i2ob_new_device,
        i2ob_del_device,
        i2ob_reboot_event,
        "I2O Block OSM",
        0,
        I2O_CLASS_RANDOM_BLOCK_STORAGE
};

/**
 *      i2ob_get        -       Get an I2O message
 *      @dev:  I2O block device
 *
 *      Get a message from the FIFO used for this block device. The message is returned
 *      or the I2O 'no message' value of 0xFFFFFFFF if nothing is available.
 */

static u32 i2ob_get(struct i2ob_device *dev)
{
        struct i2o_controller *c=dev->controller;
        return I2O_POST_READ32(c);
}
 
/**
 *      i2ob_send               -       Turn a request into a message and send it
 *      @m: Message offset
 *      @dev: I2O device
 *      @ireq: Request structure
 *      @base: Partition offset
 *      @unit: Device identity
 *
 *      Generate an I2O BSAREAD request. This interface function is called for devices that
 *      appear to explode when they are fed indirect chain pointers (notably right now this
 *      appears to afflict Promise hardwre, so be careful what you feed the hardware
 *
 *      No cleanup is done by this interface. It is done on the interrupt side when the
 *      reply arrives
 *
 *      To Fix: Generate PCI maps of the buffers
 */
 
static int i2ob_send(u32 m, struct i2ob_device *dev, struct i2ob_request *ireq, u32 base, int unit)
{
        struct i2o_controller *c = dev->controller;
        int tid = dev->tid;
        unsigned long msg;
        unsigned long mptr;
        u64 offset;
        struct request *req = ireq->req;
        struct buffer_head *bh = req->bh;
        int count = req->nr_sectors<<9;
        char *last = NULL;
        unsigned short size = 0;

        // printk(KERN_INFO "i2ob_send called\n");
        /* Map the message to a virtual address */
        msg = c->mem_offset + m;
        
        /*
         * Build the message based on the request.
         */
        __raw_writel(i2ob_context|(unit<<8), msg+8);
        __raw_writel(ireq->num, msg+12);
        __raw_writel(req->nr_sectors << 9, msg+20);

        /* 
         * Mask out partitions from now on
         */
        unit &= 0xF0;
                
        /* This can be optimised later - just want to be sure its right for
           starters */
        offset = ((u64)(req->sector+base)) << 9;
        __raw_writel( offset & 0xFFFFFFFF, msg+24);
        __raw_writel(offset>>32, msg+28);
        mptr=msg+32;
        
        if(req->cmd == READ)
        {
                DEBUG("READ\n");
                __raw_writel(I2O_CMD_BLOCK_READ<<24|HOST_TID<<12|tid, msg+4);
                while(bh!=NULL)
                {
                        if(bh->b_data == last) {
                                size += bh->b_size;
                                last += bh->b_size;
                                if(bh->b_reqnext)
                                        __raw_writel(0x10000000|(size), mptr-8);
                                else
                                        __raw_writel(0xD0000000|(size), mptr-8);
                        }
                        else
                        {
                                if(bh->b_reqnext)
                                        __raw_writel(0x10000000|(bh->b_size), mptr);
                                else
                                        __raw_writel(0xD0000000|(bh->b_size), mptr);
                                __raw_writel(virt_to_bus(bh->b_data), mptr+4);
                                mptr += 8;      
                                size = bh->b_size;
                                last = bh->b_data + size;
                        }

                        count -= bh->b_size;
                        bh = bh->b_reqnext;
                }
                switch(dev->rcache)
                {
                        case CACHE_NULL:
                                __raw_writel(0, msg+16);break;
                        case CACHE_PREFETCH:
                                __raw_writel(0x201F0008, msg+16);break;
                        case CACHE_SMARTFETCH:
                                if(req->nr_sectors > 16)
                                        __raw_writel(0x201F0008, msg+16);
                                else
                                        __raw_writel(0x001F0000, msg+16);
                                break;
                }                               
                                
//              printk("Reading %d entries %d bytes.\n",
//                      mptr-msg-8, req->nr_sectors<<9);
        }
        else if(req->cmd == WRITE)
        {
                DEBUG("WRITE\n");
                __raw_writel(I2O_CMD_BLOCK_WRITE<<24|HOST_TID<<12|tid, msg+4);
                while(bh!=NULL)
                {
                        if(bh->b_data == last) {
                                size += bh->b_size;
                                last += bh->b_size;
                                if(bh->b_reqnext)
                                        __raw_writel(0x14000000|(size), mptr-8);
                                else
                                        __raw_writel(0xD4000000|(size), mptr-8);
                        }
                        else
                        {
                                if(bh->b_reqnext)
                                        __raw_writel(0x14000000|(bh->b_size), mptr);
                                else
                                        __raw_writel(0xD4000000|(bh->b_size), mptr);
                                __raw_writel(virt_to_bus(bh->b_data), mptr+4);
                                mptr += 8;      
                                size = bh->b_size;
                                last = bh->b_data + size;
                        }

                        count -= bh->b_size;
                        bh = bh->b_reqnext;
                }

                switch(dev->wcache)
                {
                        case CACHE_NULL:
                                __raw_writel(0, msg+16);break;
                        case CACHE_WRITETHROUGH:
                                __raw_writel(0x001F0008, msg+16);break;
                        case CACHE_WRITEBACK:
                                __raw_writel(0x001F0010, msg+16);break;
                        case CACHE_SMARTBACK:
                                if(req->nr_sectors > 16)
                                        __raw_writel(0x001F0004, msg+16);
                                else
                                        __raw_writel(0x001F0010, msg+16);
                                break;
                        case CACHE_SMARTTHROUGH:
                                if(req->nr_sectors > 16)
                                        __raw_writel(0x001F0004, msg+16);
                                else
                                        __raw_writel(0x001F0010, msg+16);
                }
                                
//              printk("Writing %d entries %d bytes.\n",
//                      mptr-msg-8, req->nr_sectors<<9);
        }
        __raw_writel(I2O_MESSAGE_SIZE(mptr-msg)>>2 | SGL_OFFSET_8, msg);
        
        if(count != 0)
        {
                printk(KERN_ERR "Request count botched by %d.\n", count);
        }

        i2o_post_message(c,m);
        atomic_inc(&i2ob_queues[c->unit]->queue_depth);

        return 0;
}

/*
 *      Remove a request from the _locked_ request list. We update both the
 *      list chain and if this is the last item the tail pointer. Caller
 *      must hold the lock.
 */
 
static inline void i2ob_unhook_request(struct i2ob_request *ireq, 
        unsigned int iop)
{
        ireq->next = i2ob_queues[iop]->i2ob_qhead;
        i2ob_queues[iop]->i2ob_qhead = ireq;
}

/*
 *      Request completion handler
 */
 
static inline void i2ob_end_request(struct request *req)
{
        /* FIXME  - pci unmap the request */

        /*
         * Loop until all of the buffers that are linked
         * to this request have been marked updated and
         * unlocked.
         */

        while (end_that_request_first( req, !req->errors, "i2o block" ));

        /*
         * It is now ok to complete the request.
         */
        end_that_request_last( req );
        DEBUG("IO COMPLETED\n");
}

/*
 * Request merging functions
 */

static inline int i2ob_new_segment(request_queue_t *q, struct request *req,
                                  int __max_segments)
{
        int max_segments = i2ob_dev[MINOR(req->rq_dev)].max_segments;

        if (__max_segments < max_segments)
                max_segments = __max_segments;

        if (req->nr_segments < max_segments) {
                req->nr_segments++;
                return 1;
        }
        return 0;
}

static int i2ob_back_merge(request_queue_t *q, struct request *req, 
                             struct buffer_head *bh, int __max_segments)
{
        if (req->bhtail->b_data + req->bhtail->b_size == bh->b_data)
                return 1;
        return i2ob_new_segment(q, req, __max_segments);
}

static int i2ob_front_merge(request_queue_t *q, struct request *req, 
                              struct buffer_head *bh, int __max_segments)
{
        if (bh->b_data + bh->b_size == req->bh->b_data)
                return 1;
        return i2ob_new_segment(q, req, __max_segments);
}

static int i2ob_merge_requests(request_queue_t *q,
                                struct request *req,
                                struct request *next,
                                int __max_segments)
{
        int max_segments = i2ob_dev[MINOR(req->rq_dev)].max_segments;
        int total_segments = req->nr_segments + next->nr_segments;

        if (__max_segments < max_segments)
                max_segments = __max_segments;

        if (req->bhtail->b_data + req->bhtail->b_size == next->bh->b_data)
                total_segments--;
    
        if (total_segments > max_segments)
                return 0;

        req->nr_segments = total_segments;
        return 1;
}

static int i2ob_flush(struct i2o_controller *c, struct i2ob_device *d, int unit)
{
        unsigned long msg;
        u32 m = i2ob_get(d);
        
        if(m == 0xFFFFFFFF)
                return -1;
                
        msg = c->mem_offset + m;

        /*
         *      Ask the controller to write the cache back. This sorts out
         *      the supertrak firmware flaw and also does roughly the right
         *      thing for other cases too.
         */
                
        i2o_raw_writel(FIVE_WORD_MSG_SIZE|SGL_OFFSET_0, msg);
        i2o_raw_writel(I2O_CMD_BLOCK_CFLUSH<<24|HOST_TID<<12|d->tid, msg+4);
        i2o_raw_writel(i2ob_context|(unit<<8), msg+8);
        i2o_raw_writel(0, msg+12);
        i2o_raw_writel(60<<16, msg+16);
        DEBUG("FLUSH");
        i2o_post_message(c,m);
        return 0;
}
                        
/*
 *      OSM reply handler. This gets all the message replies
 */

static void i2o_block_reply(struct i2o_handler *h, struct i2o_controller *c, struct i2o_message *msg)
{
        unsigned long flags;
        struct i2ob_request *ireq = NULL;
        u8 st;
        u32 *m = (u32 *)msg;
        u8 unit = (m[2]>>8)&0xF0;       /* low 4 bits are partition */
        struct i2ob_device *dev = &i2ob_dev[(unit&0xF0)];

        /*
         *      Pull the lock over ready
         */     
         
        spin_lock_prefetch(&io_request_lock);
                
        /*
         * FAILed message
         */
        if(m[0] & (1<<13))
        {
                DEBUG("FAIL");
                /*
                 * FAILed message from controller
                 * We increment the error count and abort it
                 *
                 * In theory this will never happen.  The I2O block class
                 * specification states that block devices never return
                 * FAILs but instead use the REQ status field...but
                 * better be on the safe side since no one really follows
                 * the spec to the book :)
                 */
                ireq=&i2ob_queues[c->unit]->request_queue[m[3]];
                ireq->req->errors++;

                spin_lock_irqsave(&io_request_lock, flags);
                i2ob_unhook_request(ireq, c->unit);
                i2ob_end_request(ireq->req);
                spin_unlock_irqrestore(&io_request_lock, flags);
        
                /* 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;
        }

        if(msg->function == I2O_CMD_UTIL_EVT_REGISTER)
        {
                spin_lock(&i2ob_evt_lock);
                memcpy(evt_msg, msg, (m[0]>>16)<<2);
                spin_unlock(&i2ob_evt_lock);
                up(&i2ob_evt_sem);
                return;
        }

        if(!dev->i2odev)
        {
                /*
                 * This is HACK, but Intel Integrated RAID allows user
                 * to delete a volume that is claimed, locked, and in use 
                 * by the OS. We have to check for a reply from a
                 * non-existent device and flag it as an error or the system 
                 * goes kaput...
                 */
                ireq=&i2ob_queues[c->unit]->request_queue[m[3]];
                ireq->req->errors++;
                printk(KERN_WARNING "I2O Block: Data transfer to deleted device!\n");
                spin_lock_irqsave(&io_request_lock, flags);
                i2ob_unhook_request(ireq, c->unit);
                i2ob_end_request(ireq->req);
                spin_unlock_irqrestore(&io_request_lock, flags);
                return;
        }       

        /*
         *      Lets see what is cooking. We stuffed the
         *      request in the context.
         */
                 
        ireq=&i2ob_queues[c->unit]->request_queue[m[3]];
        st=m[4]>>24;

        if(st!=0)
        {
                int err;
                char *bsa_errors[] = 
                { 
                        "Success", 
                        "Media Error", 
                        "Failure communicating to device",
                        "Device Failure",
                        "Device is not ready",
                        "Media not present",
                        "Media is locked by another user",
                        "Media has failed",
                        "Failure communicating to device",
                        "Device bus failure",
                        "Device is locked by another user",
                        "Device is write protected",
                        "Device has reset",
                        "Volume has changed, waiting for acknowledgement"
                };
                                
                err = m[4]&0xFFFF;
                
                /*
                 *      Device not ready means two things. One is that the
                 *      the thing went offline (but not a removal media)
                 *
                 *      The second is that you have a SuperTrak 100 and the
                 *      firmware got constipated. Unlike standard i2o card
                 *      setups the supertrak returns an error rather than
                 *      blocking for the timeout in these cases. 
                 *
                 *      Don't stick a supertrak100 into cache aggressive modes
                 */
                 
                
                printk(KERN_ERR "\n/dev/%s error: %s", dev->i2odev->dev_name, 
                        bsa_errors[m[4]&0XFFFF]);
                if(m[4]&0x00FF0000)
                        printk(" - DDM attempted %d retries", (m[4]>>16)&0x00FF );
                printk(".\n");
                ireq->req->errors++;    
        }
        else
                ireq->req->errors = 0;

        /*
         *      Dequeue the request. We use irqsave locks as one day we
         *      may be running polled controllers from a BH...
         */
        
        spin_lock_irqsave(&io_request_lock, flags);
        i2ob_unhook_request(ireq, c->unit);
        i2ob_end_request(ireq->req);
        atomic_dec(&i2ob_queues[c->unit]->queue_depth);
        
        /*
         *      We may be able to do more I/O
         */
         
        i2ob_request(dev->req_queue);
        spin_unlock_irqrestore(&io_request_lock, flags);
}

/* 
 * Event handler.  Needs to be a separate thread b/c we may have
 * to do things like scan a partition table, or query parameters
 * which cannot be done from an interrupt or from a bottom half.
 */
static int i2ob_evt(void *dummy)
{
        unsigned int evt;
        unsigned long flags;
        int unit;
        int i;
        //The only event that has data is the SCSI_SMART event.
        struct i2o_reply {
                u32 header[4];
                u32 evt_indicator;
                u8 ASC;
                u8 ASCQ;
                u16 pad;
                u8 data[16];
                } *evt_local;

        lock_kernel();
        daemonize();
        unlock_kernel();

        strcpy(current->comm, "i2oblock");
        evt_running = 1;

        while(1)
        {
                if(down_interruptible(&i2ob_evt_sem))
                {
                        evt_running = 0;
                        printk("exiting...");
                        break;
                }

                /*
                 * Keep another CPU/interrupt from overwriting the 
                 * message while we're reading it
                 *
                 * We stuffed the unit in the TxContext and grab the event mask
                 * None of the BSA we care about events have EventData
                 */
                spin_lock_irqsave(&i2ob_evt_lock, flags);
                evt_local = (struct i2o_reply *)evt_msg;
                spin_unlock_irqrestore(&i2ob_evt_lock, flags);

                unit = le32_to_cpu(evt_local->header[3]);
                evt = le32_to_cpu(evt_local->evt_indicator);

                switch(evt)
                {
                        /*
                         * New volume loaded on same TID, so we just re-install.
                         * The TID/controller don't change as it is the same
                         * I2O device.  It's just new media that we have to
                         * rescan.
                         */
                        case I2O_EVT_IND_BSA_VOLUME_LOAD:
                        {
                                i2ob_install_device(i2ob_dev[unit].i2odev->controller, 
                                        i2ob_dev[unit].i2odev, unit);
                                break;
                        }

                        /*
                         * No media, so set all parameters to 0 and set the media
                         * change flag. The I2O device is still valid, just doesn't
                         * have media, so we don't want to clear the controller or
                         * device pointer.
                         */
                        case I2O_EVT_IND_BSA_VOLUME_UNLOAD:
                        {
                                for(i = unit; i <= unit+15; i++)
                                {
                                        i2ob_sizes[i] = 0;
                                        i2ob_hardsizes[i] = 0;
                                        i2ob_max_sectors[i] = 0;
                                        i2ob[i].nr_sects = 0;
                                        i2ob_gendisk.part[i].nr_sects = 0;
                                }
                                i2ob_media_change_flag[unit] = 1;
                                break;
                        }

                        case I2O_EVT_IND_BSA_VOLUME_UNLOAD_REQ:
                                printk(KERN_WARNING "%s: Attempt to eject locked media\n", 
                                        i2ob_dev[unit].i2odev->dev_name);
                                break;

                        /*
                         * The capacity has changed and we are going to be
                         * updating the max_sectors and other information 
                         * about this disk.  We try a revalidate first. If
                         * the block device is in use, we don't want to
                         * do that as there may be I/Os bound for the disk
                         * at the moment.  In that case we read the size 
                         * from the device and update the information ourselves
                         * and the user can later force a partition table
                         * update through an ioctl.
                         */
                        case I2O_EVT_IND_BSA_CAPACITY_CHANGE:
                        {
                                u64 size;

                                if(do_i2ob_revalidate(MKDEV(MAJOR_NR, unit),0) != -EBUSY)
                                        continue;

                                if(i2ob_query_device(&i2ob_dev[unit], 0x0004, 0, &size, 8) !=0 )
                                        i2ob_query_device(&i2ob_dev[unit], 0x0000, 4, &size, 8);

                                spin_lock_irqsave(&io_request_lock, flags);     
                                i2ob_sizes[unit] = (int)(size>>10);
                                i2ob_gendisk.part[unit].nr_sects = size>>9;
                                i2ob[unit].nr_sects = (int)(size>>9);
                                spin_unlock_irqrestore(&io_request_lock, flags);        
                                break;
                        }

                        /* 
                         * We got a SCSI SMART event, we just log the relevant
                         * information and let the user decide what they want
                         * to do with the information.
                         */
                        case I2O_EVT_IND_BSA_SCSI_SMART:
                        {
                                char buf[16];
                                printk(KERN_INFO "I2O Block: %s received a SCSI SMART Event\n",i2ob_dev[unit].i2odev->dev_name);
                                evt_local->data[16]='\0';
                                sprintf(buf,"%s",&evt_local->data[0]);
                                printk(KERN_INFO "      Disk Serial#:%s\n",buf);
                                printk(KERN_INFO "      ASC 0x%02x \n",evt_local->ASC);
                                printk(KERN_INFO "      ASCQ 0x%02x \n",evt_local->ASCQ);
                                break;
                        }
                
                        /*
                         *      Non event
                         */
                         
                        case 0:
                                break;
                                
                        /*
                         * An event we didn't ask for.  Call the card manufacturer
                         * and tell them to fix their firmware :)
                         */
                         
                        case 0x20:
                                /*
                                 * If a promise card reports 0x20 event then the brown stuff
                                 * hit the fan big time. The card seems to recover but loses
                                 * the pending writes. Deeply ungood except for testing fsck
                                 */
                                if(i2ob_dev[unit].i2odev->controller->bus.pci.promise)
                                        panic("I2O controller firmware failed. Reboot and force a filesystem check.\n");
                        default:
                                printk(KERN_INFO "%s: Received event 0x%X we didn't register for\n"
                                        KERN_INFO "   Blame the I2O card manufacturer 8)\n", 
                                        i2ob_dev[unit].i2odev->dev_name, evt);
                                break;
                }
        };

        complete_and_exit(&i2ob_thread_dead,0);
        return 0;
}

/*
 *      The I2O block driver is listed as one of those that pulls the
 *      front entry off the queue before processing it. This is important
 *      to remember here. If we drop the io lock then CURRENT will change
 *      on us. We must unlink CURRENT in this routine before we return, if
 *      we use it.
 */

static void i2ob_request(request_queue_t *q)
{
        struct request *req;
        struct i2ob_request *ireq;
        int unit;
        struct i2ob_device *dev;
        u32 m;
        
        while (!list_empty(&q->queue_head)) {
                /*
                 *      On an IRQ completion if there is an inactive
                 *      request on the queue head it means it isnt yet
                 *      ready to dispatch.
                 */
                req = blkdev_entry_next_request(&q->queue_head);

                if(req->rq_status == RQ_INACTIVE)
                        return;
                        
                unit = MINOR(req->rq_dev);
                dev = &i2ob_dev[(unit&0xF0)];

                /* 
                 *      Queue depths probably belong with some kind of 
                 *      generic IOP commit control. Certainly its not right 
                 *      its global!  
                 */
                if(atomic_read(&i2ob_queues[dev->unit]->queue_depth) >= dev->depth)
                        break;
                
                /* Get a message */
                m = i2ob_get(dev);

                if(m==0xFFFFFFFF)
                {
                        if(atomic_read(&i2ob_queues[dev->unit]->queue_depth) == 0)
                                printk(KERN_ERR "i2o_block: message queue and request queue empty!!\n");
                        break;
                }
                /*
                 * Everything ok, so pull from kernel queue onto our queue
                 */
                req->errors = 0;
                blkdev_dequeue_request(req);    
                req->waiting = NULL;
                
                ireq = i2ob_queues[dev->unit]->i2ob_qhead;
                i2ob_queues[dev->unit]->i2ob_qhead = ireq->next;
                ireq->req = req;

                i2ob_send(m, dev, ireq, i2ob[unit].start_sect, (unit&0xF0));
        }
}


/*
 *      SCSI-CAM for ioctl geometry mapping
 *      Duplicated with SCSI - this should be moved into somewhere common
 *      perhaps genhd ?
 *
 * LBA -> CHS mapping table taken from:
 *
 * "Incorporating the I2O Architecture into BIOS for Intel Architecture 
 *  Platforms" 
 *
 * This is an I2O document that is only available to I2O members,
 * not developers.
 *
 * From my understanding, this is how all the I2O cards do this
 *
 * Disk Size      | Sectors | Heads | Cylinders
 * ---------------+---------+-------+-------------------
 * 1 < X <= 528M  | 63      | 16    | X/(63 * 16 * 512)
 * 528M < X <= 1G | 63      | 32    | X/(63 * 32 * 512)
 * 1 < X <528M    | 63      | 16    | X/(63 * 16 * 512)
 * 1 < X <528M    | 63      | 16    | X/(63 * 16 * 512)
 *
 */
#define BLOCK_SIZE_528M         1081344
#define BLOCK_SIZE_1G           2097152
#define BLOCK_SIZE_21G          4403200
#define BLOCK_SIZE_42G          8806400
#define BLOCK_SIZE_84G          17612800

static void i2o_block_biosparam(
        unsigned long capacity,
        unsigned short *cyls,
        unsigned char *hds,
        unsigned char *secs) 
{ 
        unsigned long heads, sectors, cylinders; 

        sectors = 63L;                          /* Maximize sectors per track */ 
        if(capacity <= BLOCK_SIZE_528M)
                heads = 16;
        else if(capacity <= BLOCK_SIZE_1G)
                heads = 32;
        else if(capacity <= BLOCK_SIZE_21G)
                heads = 64;
        else if(capacity <= BLOCK_SIZE_42G)
                heads = 128;
        else
                heads = 255;

        cylinders = capacity / (heads * sectors);

        *cyls = (unsigned short) cylinders;     /* Stuff return values */ 
        *secs = (unsigned char) sectors; 
        *hds  = (unsigned char) heads; 
}


/*
 *      Rescan the partition tables
 */
 
static int do_i2ob_revalidate(kdev_t dev, int maxu)
{
        int minor=MINOR(dev);
        int i;
        
        minor&=0xF0;

        i2ob_dev[minor].refcnt++;
        if(i2ob_dev[minor].refcnt>maxu+1)
        {
                i2ob_dev[minor].refcnt--;
                return -EBUSY;
        }
        
        for( i = 15; i>=0 ; i--)
        {
                int m = minor+i;
                invalidate_device(MKDEV(MAJOR_NR, m), 1);
                i2ob_gendisk.part[m].start_sect = 0;
                i2ob_gendisk.part[m].nr_sects = 0;
        }

        /*
         *      Do a physical check and then reconfigure
         */
         
        i2ob_install_device(i2ob_dev[minor].controller, i2ob_dev[minor].i2odev,
                minor);
        i2ob_dev[minor].refcnt--;
        return 0;
}

/*
 *      Issue device specific ioctl calls.
 */

static int i2ob_ioctl(struct inode *inode, struct file *file,
                     unsigned int cmd, unsigned long arg)
{
        struct i2ob_device *dev;
        int minor;

        /* Anyone capable of this syscall can do *real bad* things */

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;
        if (!inode)
                return -EINVAL;
        minor = MINOR(inode->i_rdev);
        if (minor >= (MAX_I2OB<<4))
                return -ENODEV;

        dev = &i2ob_dev[minor];
        switch (cmd) {
                case HDIO_GETGEO:
                {
                        struct hd_geometry g;
                        int u=minor&0xF0;
                        i2o_block_biosparam(i2ob_sizes[u]<<1, 
                                &g.cylinders, &g.heads, &g.sectors);
                        g.start = i2ob[minor].start_sect;
                        return copy_to_user((void *)arg,&g, sizeof(g))?-EFAULT:0;
                }
                
                case BLKI2OGRSTRAT:
                        return put_user(dev->rcache, (int *)arg);
                case BLKI2OGWSTRAT:
                        return put_user(dev->wcache, (int *)arg);
                case BLKI2OSRSTRAT:
                        if(arg<0||arg>CACHE_SMARTFETCH)
                                return -EINVAL;
                        dev->rcache = arg;
                        break;
                case BLKI2OSWSTRAT:
                        if(arg!=0 && (arg<CACHE_WRITETHROUGH || arg>CACHE_SMARTBACK))
                                return -EINVAL;
                        dev->wcache = arg;
                        break;
        
                case BLKRRPART:
                        if(!capable(CAP_SYS_ADMIN))
                                return -EACCES;
                        return do_i2ob_revalidate(inode->i_rdev,1);
                        
                default:
                        return blk_ioctl(inode->i_rdev, cmd, arg);
        }
        return 0;
}

/*
 *      Close the block device down
 */
 
static int i2ob_release(struct inode *inode, struct file *file)
{
        struct i2ob_device *dev;
        int minor;

        minor = MINOR(inode->i_rdev);
        if (minor >= (MAX_I2OB<<4))
                return -ENODEV;
        dev = &i2ob_dev[(minor&0xF0)];

        /*
         * This is to deail with the case of an application
         * opening a device and then the device dissapears while
         * it's in use, and then the application tries to release
         * it.  ex: Unmounting a deleted RAID volume at reboot. 
         * If we send messages, it will just cause FAILs since
         * the TID no longer exists.
         */
        if(!dev->i2odev)
                return 0;

        if (dev->refcnt <= 0)
                printk(KERN_ALERT "i2ob_release: refcount(%d) <= 0\n", dev->refcnt);
        dev->refcnt--;
        if(dev->refcnt==0)
        {
                /*
                 *      Flush the onboard cache on unmount
                 */
                u32 msg[5];
                int *query_done = &dev->done_flag;
                msg[0] = (FIVE_WORD_MSG_SIZE|SGL_OFFSET_0);
                msg[1] = I2O_CMD_BLOCK_CFLUSH<<24|HOST_TID<<12|dev->tid;
                msg[2] = i2ob_context|0x40000000;
                msg[3] = (u32)query_done;
                msg[4] = 60<<16;
                DEBUG("Flushing...");
                i2o_post_wait(dev->controller, msg, 20, 60);

                /*
                 *      Unlock the media
                 */
                msg[0] = FIVE_WORD_MSG_SIZE|SGL_OFFSET_0;
                msg[1] = I2O_CMD_BLOCK_MUNLOCK<<24|HOST_TID<<12|dev->tid;
                msg[2] = i2ob_context|0x40000000;
                msg[3] = (u32)query_done;
                msg[4] = -1;
                DEBUG("Unlocking...");
                i2o_post_wait(dev->controller, msg, 20, 2);
                DEBUG("Unlocked.\n");

                msg[0] = FOUR_WORD_MSG_SIZE|SGL_OFFSET_0;
                msg[1] = I2O_CMD_BLOCK_POWER<<24 | HOST_TID << 12 | dev->tid;
                if(dev->flags & (1<<3|1<<4))    /* Removable */
                        msg[4] = 0x21 << 24;
                else
                        msg[4] = 0x24 << 24;

                if(i2o_post_wait(dev->controller, msg, 20, 60)==0)
                        dev->power = 0x24;

                /*
                 * Now unclaim the device.
                 */

                if (i2o_release_device(dev->i2odev, &i2o_block_handler))
                        printk(KERN_ERR "i2ob_release: controller rejected unclaim.\n");
                
                DEBUG("Unclaim\n");
        }
        return 0;
}

/*
 *      Open the block device.
 */
 
static int i2ob_open(struct inode *inode, struct file *file)
{
        int minor;
        struct i2ob_device *dev;
        
        if (!inode)
                return -EINVAL;
        minor = MINOR(inode->i_rdev);
        if (minor >= MAX_I2OB<<4)
                return -ENODEV;
        dev=&i2ob_dev[(minor&0xF0)];

        if(!dev->i2odev)        
                return -ENODEV;
        
        if(dev->refcnt++==0)
        { 
                u32 msg[6];
                
                DEBUG("Claim ");
                if(i2o_claim_device(dev->i2odev, &i2o_block_handler))
                {
                        dev->refcnt--;
                        printk(KERN_INFO "I2O Block: Could not open device\n");
                        return -EBUSY;
                }
                DEBUG("Claimed ");
                /*
                 *      Power up if needed
                 */

                if(dev->power > 0x1f)
                {
                        msg[0] = FOUR_WORD_MSG_SIZE|SGL_OFFSET_0;
                        msg[1] = I2O_CMD_BLOCK_POWER<<24 | HOST_TID << 12 | dev->tid;
                        msg[4] = 0x02 << 24;
                        if(i2o_post_wait(dev->controller, msg, 20, 60) == 0)
                                dev->power = 0x02;
                }

                /*
                 *      Mount the media if needed. Note that we don't use
                 *      the lock bit. Since we have to issue a lock if it
                 *      refuses a mount (quite possible) then we might as
                 *      well just send two messages out.
                 */
                msg[0] = FIVE_WORD_MSG_SIZE|SGL_OFFSET_0;               
                msg[1] = I2O_CMD_BLOCK_MMOUNT<<24|HOST_TID<<12|dev->tid;
                msg[4] = -1;
                msg[5] = 0;
                DEBUG("Mount ");
                i2o_post_wait(dev->controller, msg, 24, 2);

                /*
                 *      Lock the media
                 */
                msg[0] = FIVE_WORD_MSG_SIZE|SGL_OFFSET_0;
                msg[1] = I2O_CMD_BLOCK_MLOCK<<24|HOST_TID<<12|dev->tid;
                msg[4] = -1;
                DEBUG("Lock ");
                i2o_post_wait(dev->controller, msg, 20, 2);
                DEBUG("Ready.\n");
        }               
        return 0;
}

/*
 *      Issue a device query
 */
 
static int i2ob_query_device(struct i2ob_device *dev, int table, 
        int field, void *buf, int buflen)
{
        return i2o_query_scalar(dev->controller, dev->tid,
                table, field, buf, buflen);
}


/*
 *      Install the I2O block device we found.
 */
 
static int i2ob_install_device(struct i2o_controller *c, struct i2o_device *d, int unit)
{
        u64 size;
        u32 blocksize;
        u8 type;
        u16 power;
        u32 flags, status;
        struct i2ob_device *dev=&i2ob_dev[unit];
        int i;

        /*
         * For logging purposes...
         */
        printk(KERN_INFO "i2ob: Installing tid %d device at unit %d\n", 
                        d->lct_data.tid, unit); 

        /*
         *      Ask for the current media data. If that isn't supported
         *      then we ask for the device capacity data
         */
        if(i2ob_query_device(dev, 0x0004, 1, &blocksize, 4) != 0
          || i2ob_query_device(dev, 0x0004, 0, &size, 8) !=0 )
        {
                i2ob_query_device(dev, 0x0000, 3, &blocksize, 4);
                i2ob_query_device(dev, 0x0000, 4, &size, 8);
        }
        
        if(i2ob_query_device(dev, 0x0000, 2, &power, 2)!=0)
                power = 0;
        i2ob_query_device(dev, 0x0000, 5, &flags, 4);
        i2ob_query_device(dev, 0x0000, 6, &status, 4);
        i2ob_sizes[unit] = (int)(size>>10);
        for(i=unit; i <= unit+15 ; i++)
                i2ob_hardsizes[i] = blocksize;
        i2ob_gendisk.part[unit].nr_sects = size>>9;
        i2ob[unit].nr_sects = (int)(size>>9);

        /*
         * Max number of Scatter-Gather Elements
         */     

        i2ob_dev[unit].power = power;   /* Save power state in device proper */
        i2ob_dev[unit].flags = flags;

        for(i=unit;i<=unit+15;i++)
        {
                i2ob_dev[i].power = power;      /* Save power state */
                i2ob_dev[unit].flags = flags;   /* Keep the type info */
                i2ob_max_sectors[i] = 96;       /* 256 might be nicer but many controllers 
                                                   explode on 65536 or higher */
                i2ob_dev[i].max_segments = (d->controller->status_block->inbound_frame_size - 7) / 2;
                
                i2ob_dev[i].rcache = CACHE_SMARTFETCH;
                i2ob_dev[i].wcache = CACHE_WRITETHROUGH;
                
                if(d->controller->battery == 0)
                        i2ob_dev[i].wcache = CACHE_WRITETHROUGH;

                if(d->controller->type == I2O_TYPE_PCI && d->controller->bus.pci.promise)
                        i2ob_dev[i].wcache = CACHE_WRITETHROUGH;

                if(d->controller->type == I2O_TYPE_PCI && d->controller->bus.pci.short_req)
                {
                        i2ob_max_sectors[i] = 8;
                        i2ob_dev[i].max_segments = 8;
                }
        }

        sprintf(d->dev_name, "%s%c", i2ob_gendisk.major_name, 'a' + (unit>>4));

        printk(KERN_INFO "%s: Max segments %d, queue depth %d, byte limit %d.\n",
                 d->dev_name, i2ob_dev[unit].max_segments, i2ob_dev[unit].depth, i2ob_max_sectors[unit]<<9);

        i2ob_query_device(dev, 0x0000, 0, &type, 1);

        printk(KERN_INFO "%s: ", d->dev_name);
        switch(type)
        {
                case 0: printk("Disk Storage");break;
                case 4: printk("WORM");break;
                case 5: printk("CD-ROM");break;
                case 7: printk("Optical device");break;
                default:
                        printk("Type %d", type);
        }
        if(status&(1<<10))
                printk("(RAID)");

        if((flags^status)&(1<<4|1<<3))  /* Missing media or device */
        {
                printk(KERN_INFO " Not loaded.\n");
                /* Device missing ? */
                if((flags^status)&(1<<4))
                        return 1;
        }
        else
        {
                printk(": %dMB, %d byte sectors",
                        (int)(size>>20), blocksize);
        }
        if(status&(1<<0))
        {
                u32 cachesize;
                i2ob_query_device(dev, 0x0003, 0, &cachesize, 4);
                cachesize>>=10;
                if(cachesize>4095)
                        printk(", %dMb cache", cachesize>>10);
                else
                        printk(", %dKb cache", cachesize);
        }
        printk(".\n");
        printk(KERN_INFO "%s: Maximum sectors/read set to %d.\n", 
                d->dev_name, i2ob_max_sectors[unit]);

        /* 
         * If this is the first I2O block device found on this IOP,
         * we need to initialize all the queue data structures
         * before any I/O can be performed. If it fails, this
         * device is useless.
         */
        if(!i2ob_queues[c->unit]) {
                if(i2ob_init_iop(c->unit))
                        return 1;
        }

        /* 
         * This will save one level of lookup/indirection in critical 
         * code so that we can directly get the queue ptr from the
         * device instead of having to go the IOP data structure.
         */
        dev->req_queue = &i2ob_queues[c->unit]->req_queue;

        grok_partitions(&i2ob_gendisk, unit>>4, 1<<4, (long)(size>>9));

        /*
         * Register for the events we're interested in and that the
         * device actually supports.
         */
        i2o_event_register(c, d->lct_data.tid, i2ob_context, unit, 
                (I2OB_EVENT_MASK & d->lct_data.event_capabilities));

        return 0;
}

/*
 * Initialize IOP specific queue structures.  This is called
 * once for each IOP that has a block device sitting behind it.
 */
static int i2ob_init_iop(unsigned int unit)
{
        int i;

        i2ob_queues[unit] = (struct i2ob_iop_queue *) kmalloc(sizeof(struct i2ob_iop_queue), GFP_ATOMIC);
        if(!i2ob_queues[unit])
        {
                printk(KERN_WARNING "Could not allocate request queue for I2O block device!\n");
                return -1;
        }

        for(i = 0; i< MAX_I2OB_DEPTH; i++)
        {
                i2ob_queues[unit]->request_queue[i].next =  &i2ob_queues[unit]->request_queue[i+1];
                i2ob_queues[unit]->request_queue[i].num = i;
        }
        
        /* Queue is MAX_I2OB + 1... */
        i2ob_queues[unit]->request_queue[i].next = NULL;
        i2ob_queues[unit]->i2ob_qhead = &i2ob_queues[unit]->request_queue[0];
        atomic_set(&i2ob_queues[unit]->queue_depth, 0);

        blk_init_queue(&i2ob_queues[unit]->req_queue, i2ob_request);
        blk_queue_headactive(&i2ob_queues[unit]->req_queue, 0);
        i2ob_queues[unit]->req_queue.back_merge_fn = i2ob_back_merge;
        i2ob_queues[unit]->req_queue.front_merge_fn = i2ob_front_merge;
        i2ob_queues[unit]->req_queue.merge_requests_fn = i2ob_merge_requests;
        i2ob_queues[unit]->req_queue.queuedata = &i2ob_queues[unit];

        return 0;
}

/*
 * Get the request queue for the given device.
 */     
static request_queue_t* i2ob_get_queue(kdev_t dev)
{
        int unit = MINOR(dev)&0xF0;
        return i2ob_dev[unit].req_queue;
}

/*
 * Probe the I2O subsytem for block class devices
 */
static void i2ob_scan(int bios)
{
        int i;
        int warned = 0;

        struct i2o_device *d, *b=NULL;
        struct i2o_controller *c;
        struct i2ob_device *dev;
                
        for(i=0; i< MAX_I2O_CONTROLLERS; i++)
        {
                c=i2o_find_controller(i);
        
                if(c==NULL)
                        continue;

                /*
                 *    The device list connected to the I2O Controller is doubly linked
                 * Here we traverse the end of the list , and start claiming devices
                 * from that end. This assures that within an I2O controller atleast
                 * the newly created volumes get claimed after the older ones, thus
                 * mapping to same major/minor (and hence device file name) after 
                 * every reboot.
                 * The exception being: 
                 * 1. If there was a TID reuse.
                 * 2. There was more than one I2O controller. 
                 */

                if(!bios)
                {
                        for (d=c->devices;d!=NULL;d=d->next)
                        if(d->next == NULL)
                                b = d;
                }
                else
                        b = c->devices;

                while(b != NULL)
                {
                        d=b;
                        if(bios)
                                b = b->next;
                        else
                                b = b->prev;

                        if(d->lct_data.class_id!=I2O_CLASS_RANDOM_BLOCK_STORAGE)
                                continue;

                        if(d->lct_data.user_tid != 0xFFF)
                                continue;

                        if(bios)
                        {
                                if(d->lct_data.bios_info != 0x80)
                                        continue;
                                printk(KERN_INFO "Claiming as Boot device: Controller %d, TID %d\n", c->unit, d->lct_data.tid);
                        }
                        else
                        {
                                if(d->lct_data.bios_info == 0x80)
                                        continue; /*Already claimed on pass 1 */
                        }

                        if(i2o_claim_device(d, &i2o_block_handler))
                        {
                                printk(KERN_WARNING "i2o_block: Controller %d, TID %d\n", c->unit,
                                        d->lct_data.tid);
                                printk(KERN_WARNING "\t%sevice refused claim! Skipping installation\n", bios?"Boot d":"D");
                                continue;
                        }

                        if(scan_unit<MAX_I2OB<<4)
                        {
                                /*
                                 * Get the device and fill in the
                                 * Tid and controller.
                                 */
                                dev=&i2ob_dev[scan_unit];
                                dev->i2odev = d; 
                                dev->controller = c;
                                dev->unit = c->unit;
                                dev->tid = d->lct_data.tid;

                                if(i2ob_install_device(c,d,scan_unit))
                                        printk(KERN_WARNING "Could not install I2O block device\n");
                                else
                                {
                                        scan_unit+=16;
                                        i2ob_dev_count++;

                                        /* We want to know when device goes away */
                                        i2o_device_notify_on(d, &i2o_block_handler);
                                }
                        }
                        else
                        {
                                if(!warned++)
                                        printk(KERN_WARNING "i2o_block: too many device, registering only %d.\n", scan_unit>>4);
                        }
                        i2o_release_device(d, &i2o_block_handler);
                }
                i2o_unlock_controller(c);
        }
}

static void i2ob_probe(void)
{
        /*
         *      Some overhead/redundancy involved here, while trying to
         *      claim the first boot volume encountered as /dev/i2o/hda
         *      everytime. All the i2o_controllers are searched and the
         *      first i2o block device marked as bootable is claimed
         *      If an I2O block device was booted off , the bios sets
         *      its bios_info field to 0x80, this what we search for.
         *      Assuming that the bootable volume is /dev/i2o/hda
         *      everytime will prevent any kernel panic while mounting
         *      root partition
         */

        printk(KERN_INFO "i2o_block: Checking for Boot device...\n");
        i2ob_scan(1);

        /*
         *      Now the remainder.
         */
        printk(KERN_INFO "i2o_block: Checking for I2O Block devices...\n");
        i2ob_scan(0);
}


/*
 * New device notification handler.  Called whenever a new
 * I2O block storage device is added to the system.
 * 
 * Should we spin lock around this to keep multiple devs from 
 * getting updated at the same time? 
 * 
 */
void i2ob_new_device(struct i2o_controller *c, struct i2o_device *d)
{
        struct i2ob_device *dev;
        int unit = 0;

        printk(KERN_INFO "i2o_block: New device detected\n");
        printk(KERN_INFO "   Controller %d Tid %d\n",c->unit, d->lct_data.tid);

        /* Check for available space */
        if(i2ob_dev_count>=MAX_I2OB<<4)
        {
                printk(KERN_ERR "i2o_block: No more devices allowed!\n");
                return;
        }
        for(unit = 0; unit < (MAX_I2OB<<4); unit += 16)
        {
                if(!i2ob_dev[unit].i2odev)
                        break;
        }

        if(i2o_claim_device(d, &i2o_block_handler))
        {
                printk(KERN_INFO "i2o_block: Unable to claim device. Installation aborted\n");
                return;
        }

        dev = &i2ob_dev[unit];
        dev->i2odev = d; 
        dev->controller = c;
        dev->tid = d->lct_data.tid;

        if(i2ob_install_device(c,d,unit))
                printk(KERN_ERR "i2o_block: Could not install new device\n");
        else    
        {
                i2ob_dev_count++;
                i2o_device_notify_on(d, &i2o_block_handler);
        }

        i2o_release_device(d, &i2o_block_handler);
 
        return;
}

/*
 * Deleted device notification handler.  Called when a device we
 * are talking to has been deleted by the user or some other
 * mysterious fource outside the kernel.
 */
void i2ob_del_device(struct i2o_controller *c, struct i2o_device *d)
{       
        int unit = 0;
        int i = 0;
        unsigned long flags;

        spin_lock_irqsave(&io_request_lock, flags);

        /*
         * Need to do this...we somtimes get two events from the IRTOS
         * in a row and that causes lots of problems.
         */
        i2o_device_notify_off(d, &i2o_block_handler);

        printk(KERN_INFO "I2O Block Device Deleted\n");

        for(unit = 0; unit < MAX_I2OB<<4; unit += 16)
        {
                if(i2ob_dev[unit].i2odev == d)
                {
                        printk(KERN_INFO "  /dev/%s: Controller %d Tid %d\n", 
                                d->dev_name, c->unit, d->lct_data.tid);
                        break;
                }
        }
        if(unit >= MAX_I2OB<<4)
        {
                printk(KERN_ERR "i2ob_del_device called, but not in dev table!\n");
                spin_unlock_irqrestore(&io_request_lock, flags);
                return;
        }

        /* 
         * This will force errors when i2ob_get_queue() is called
         * by the kenrel.
         */
        i2ob_dev[unit].req_queue = NULL;
        for(i = unit; i <= unit+15; i++)
        {
                i2ob_dev[i].i2odev = NULL;
                i2ob_sizes[i] = 0;
                i2ob_hardsizes[i] = 0;
                i2ob_max_sectors[i] = 0;
                i2ob[i].nr_sects = 0;
                i2ob_gendisk.part[i].nr_sects = 0;
        }
        spin_unlock_irqrestore(&io_request_lock, flags);

        /*
         * Decrease usage count for module
         */     

        while(i2ob_dev[unit].refcnt--)
                MOD_DEC_USE_COUNT;

        i2ob_dev[unit].refcnt = 0;
        
        i2ob_dev[i].tid = 0;

        /* 
         * Do we need this?
         * The media didn't really change...the device is just gone
         */
        i2ob_media_change_flag[unit] = 1;

        i2ob_dev_count--;       
}

/*
 *      Have we seen a media change ?
 */
static int i2ob_media_change(kdev_t dev)
{
        int i=MINOR(dev);
        i>>=4;
        if(i2ob_media_change_flag[i])
        {
                i2ob_media_change_flag[i]=0;
                return 1;
        }
        return 0;
}

static int i2ob_revalidate(kdev_t dev)
{
        return do_i2ob_revalidate(dev, 0);
}

/*
 * Reboot notifier.  This is called by i2o_core when the system
 * shuts down.
 */
static void i2ob_reboot_event(void)
{
        int i;
        
        for(i=0;i<MAX_I2OB;i++)
        {
                struct i2ob_device *dev=&i2ob_dev[(i<<4)];
                
                if(dev->refcnt!=0)
                {
                        /*
                         *      Flush the onboard cache
                         */
                        u32 msg[5];
                        int *query_done = &dev->done_flag;
                        msg[0] = FIVE_WORD_MSG_SIZE|SGL_OFFSET_0;
                        msg[1] = I2O_CMD_BLOCK_CFLUSH<<24|HOST_TID<<12|dev->tid;
                        msg[2] = i2ob_context|0x40000000;
                        msg[3] = (u32)query_done;
                        msg[4] = 60<<16;
                        
                        DEBUG("Flushing...");
                        i2o_post_wait(dev->controller, msg, 20, 60);

                        DEBUG("Unlocking...");
                        /*
                         *      Unlock the media
                         */
                        msg[0] = FIVE_WORD_MSG_SIZE|SGL_OFFSET_0;
                        msg[1] = I2O_CMD_BLOCK_MUNLOCK<<24|HOST_TID<<12|dev->tid;
                        msg[2] = i2ob_context|0x40000000;
                        msg[3] = (u32)query_done;
                        msg[4] = -1;
                        i2o_post_wait(dev->controller, msg, 20, 2);
                        
                        DEBUG("Unlocked.\n");
                }
        }       
}

static struct block_device_operations i2ob_fops =
{
        owner:                  THIS_MODULE,
        open:                   i2ob_open,
        release:                i2ob_release,
        ioctl:                  i2ob_ioctl,
        check_media_change:     i2ob_media_change,
        revalidate:             i2ob_revalidate,
};

static struct gendisk i2ob_gendisk = 
{
        major:          MAJOR_NR,
        major_name:     "i2o/hd",
        minor_shift:    4,
        max_p:          1<<4,
        part:           i2ob,
        sizes:          i2ob_sizes,
        nr_real:        MAX_I2OB,
        fops:           &i2ob_fops,
};


/*
 * And here should be modules and kernel interface 
 *  (Just smiley confuses emacs :-)
 */

static int i2o_block_init(void)
{
        int i;

        printk(KERN_INFO "I2O Block Storage OSM v0.9\n");
        printk(KERN_INFO "   (c) Copyright 1999-2001 Red Hat Software.\n");
        
        /*
         *      Register the block device interfaces
         */

        if (register_blkdev(MAJOR_NR, "i2o_block", &i2ob_fops)) {
                printk(KERN_ERR "Unable to get major number %d for i2o_block\n",
                       MAJOR_NR);
                return -EIO;
        }
#ifdef MODULE
        printk(KERN_INFO "i2o_block: registered device at major %d\n", MAJOR_NR);
#endif

        /*
         *      Now fill in the boiler plate
         */
         
        blksize_size[MAJOR_NR] = i2ob_blksizes;
        hardsect_size[MAJOR_NR] = i2ob_hardsizes;
        blk_size[MAJOR_NR] = i2ob_sizes;
        max_sectors[MAJOR_NR] = i2ob_max_sectors;
        blk_dev[MAJOR_NR].queue = i2ob_get_queue;
        
        blk_init_queue(BLK_DEFAULT_QUEUE(MAJOR_NR), i2ob_request);
        blk_queue_headactive(BLK_DEFAULT_QUEUE(MAJOR_NR), 0);

        for (i = 0; i < MAX_I2OB << 4; i++) {
                i2ob_dev[i].refcnt = 0;
                i2ob_dev[i].flags = 0;
                i2ob_dev[i].controller = NULL;
                i2ob_dev[i].i2odev = NULL;
                i2ob_dev[i].tid = 0;
                i2ob_dev[i].head = NULL;
                i2ob_dev[i].tail = NULL;
                i2ob_dev[i].depth = MAX_I2OB_DEPTH;
                i2ob_blksizes[i] = 1024;
                i2ob_max_sectors[i] = 2;
        }
        
        /*
         *      Set up the queue
         */
        for(i = 0; i < MAX_I2O_CONTROLLERS; i++)
        {
                i2ob_queues[i] = NULL;
        }

        /*
         *      Register the OSM handler as we will need this to probe for
         *      drives, geometry and other goodies.
         */

        if(i2o_install_handler(&i2o_block_handler)<0)
        {
                unregister_blkdev(MAJOR_NR, "i2o_block");
                blk_cleanup_queue(BLK_DEFAULT_QUEUE(MAJOR_NR));
                printk(KERN_ERR "i2o_block: unable to register OSM.\n");
                return -EINVAL;
        }
        i2ob_context = i2o_block_handler.context;        

        /*
         * Initialize event handling thread
         */
        init_MUTEX_LOCKED(&i2ob_evt_sem);
        evt_pid = kernel_thread(i2ob_evt, NULL, CLONE_SIGHAND);
        if(evt_pid < 0)
        {
                printk(KERN_ERR 
                        "i2o_block: Could not initialize event thread.  Aborting\n");
                i2o_remove_handler(&i2o_block_handler);
                return 0;
        }

        /*
         *      Finally see what is actually plugged in to our controllers
         */
        for (i = 0; i < MAX_I2OB; i++)
                register_disk(&i2ob_gendisk, MKDEV(MAJOR_NR,i<<4), 1<<4,
                        &i2ob_fops, 0);
        i2ob_probe();

        /*
         *      Adding i2ob_gendisk into the gendisk list.
         */
        add_gendisk(&i2ob_gendisk);

        return 0;
}


static void i2o_block_exit(void)
{
        int i;
        
        if(evt_running) {
                printk(KERN_INFO "Killing I2O block threads...");
                i = kill_proc(evt_pid, SIGTERM, 1);
                if(!i) {
                        printk("waiting...");
                }
                /* Be sure it died */
                wait_for_completion(&i2ob_thread_dead);
                printk("done.\n");
        }

        /*
         * Unregister for updates from any devices..otherwise we still
         * get them and the core jumps to random memory :O
         */
        if(i2ob_dev_count) {
                struct i2o_device *d;
                for(i = 0; i < MAX_I2OB; i++)
                if((d=i2ob_dev[i<<4].i2odev)) {
                        i2o_device_notify_off(d, &i2o_block_handler);
                        i2o_event_register(d->controller, d->lct_data.tid, 
                                i2ob_context, i<<4, 0);
                }
        }
        
        /*
         *      We may get further callbacks for ourself. The i2o_core
         *      code handles this case reasonably sanely. The problem here
         *      is we shouldn't get them .. but a couple of cards feel 
         *      obliged to tell us stuff we dont care about.
         *
         *      This isnt ideal at all but will do for now.
         */
         
        set_current_state(TASK_UNINTERRUPTIBLE);
        schedule_timeout(HZ);
        
        /*
         *      Flush the OSM
         */

        i2o_remove_handler(&i2o_block_handler);
                 
        /*
         *      Return the block device
         */
        if (unregister_blkdev(MAJOR_NR, "i2o_block") != 0)
                printk("i2o_block: cleanup_module failed\n");

        /*
         * free request queue
         */
        blk_cleanup_queue(BLK_DEFAULT_QUEUE(MAJOR_NR));

        del_gendisk(&i2ob_gendisk);
}

EXPORT_NO_SYMBOLS;
MODULE_AUTHOR("Red Hat Software");
MODULE_DESCRIPTION("I2O Block Device OSM");
MODULE_LICENSE("GPL");

module_init(i2o_block_init);
module_exit(i2o_block_exit);