cmd64x: don't clear the other channel's interrupt

[linux-2.6/linux-mips/linux-dm7025.git] / drivers / message / i2o / i2o_scsi.c

/*
 * 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.
 *
 * For the avoidance of doubt the "preferred form" of this code is one which
 * is in an open non patent encumbered format. Where cryptographic key signing
 * forms part of the process of creating an executable the information
 * including keys needed to generate an equivalently functional executable
 * are deemed to be part of the source code.
 *
 *  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/additions:
 *      Steve Ralston:
 *              Scatter gather now works
 *      Markus Lidel <Markus.Lidel@shadowconnect.com>:
 *              Minor fixes for 2.6.
 *
 * 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/jiffies.h>
#include <linux/interrupt.h>
#include <linux/timer.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/prefetch.h>
#include <linux/pci.h>
#include <linux/blkdev.h>
#include <linux/i2o.h>
#include <linux/scatterlist.h>

#include <asm/dma.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/atomic.h>

#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/sg.h>

#define OSM_NAME        "scsi-osm"
#define OSM_VERSION     "1.316"
#define OSM_DESCRIPTION "I2O SCSI Peripheral OSM"

static struct i2o_driver i2o_scsi_driver;

static unsigned int i2o_scsi_max_id = 16;
static unsigned int i2o_scsi_max_lun = 255;

struct i2o_scsi_host {
        struct Scsi_Host *scsi_host;    /* pointer to the SCSI host */
        struct i2o_controller *iop;     /* pointer to the I2O controller */
        unsigned int lun;       /* lun's used for block devices */
        struct i2o_device *channel[0];  /* channel->i2o_dev mapping table */
};

static struct scsi_host_template i2o_scsi_host_template;

#define I2O_SCSI_CAN_QUEUE      4

/* SCSI OSM class handling definition */
static struct i2o_class_id i2o_scsi_class_id[] = {
        {I2O_CLASS_SCSI_PERIPHERAL},
        {I2O_CLASS_END}
};

static struct i2o_scsi_host *i2o_scsi_host_alloc(struct i2o_controller *c)
{
        struct i2o_scsi_host *i2o_shost;
        struct i2o_device *i2o_dev;
        struct Scsi_Host *scsi_host;
        int max_channel = 0;
        u8 type;
        int i;
        size_t size;
        u16 body_size = 6;

#ifdef CONFIG_I2O_EXT_ADAPTEC
        if (c->adaptec)
                body_size = 8;
#endif

        list_for_each_entry(i2o_dev, &c->devices, list)
            if (i2o_dev->lct_data.class_id == I2O_CLASS_BUS_ADAPTER) {
                if (!i2o_parm_field_get(i2o_dev, 0x0000, 0, &type, 1)
                    && (type == 0x01))  /* SCSI bus */
                        max_channel++;
        }

        if (!max_channel) {
                osm_warn("no channels found on %s\n", c->name);
                return ERR_PTR(-EFAULT);
        }

        size = max_channel * sizeof(struct i2o_device *)
            + sizeof(struct i2o_scsi_host);

        scsi_host = scsi_host_alloc(&i2o_scsi_host_template, size);
        if (!scsi_host) {
                osm_warn("Could not allocate SCSI host\n");
                return ERR_PTR(-ENOMEM);
        }

        scsi_host->max_channel = max_channel - 1;
        scsi_host->max_id = i2o_scsi_max_id;
        scsi_host->max_lun = i2o_scsi_max_lun;
        scsi_host->this_id = c->unit;
        scsi_host->sg_tablesize = i2o_sg_tablesize(c, body_size);

        i2o_shost = (struct i2o_scsi_host *)scsi_host->hostdata;
        i2o_shost->scsi_host = scsi_host;
        i2o_shost->iop = c;
        i2o_shost->lun = 1;

        i = 0;
        list_for_each_entry(i2o_dev, &c->devices, list)
            if (i2o_dev->lct_data.class_id == I2O_CLASS_BUS_ADAPTER) {
                if (!i2o_parm_field_get(i2o_dev, 0x0000, 0, &type, 1)
                    && (type == 0x01))  /* only SCSI bus */
                        i2o_shost->channel[i++] = i2o_dev;

                if (i >= max_channel)
                        break;
        }

        return i2o_shost;
};

/**
 *      i2o_scsi_get_host - Get an I2O SCSI host
 *      @c: I2O controller to for which to get the SCSI host
 *
 *      If the I2O controller already exists as SCSI host, the SCSI host
 *      is returned, otherwise the I2O controller is added to the SCSI
 *      core.
 *
 *      Returns pointer to the I2O SCSI host on success or NULL on failure.
 */
static struct i2o_scsi_host *i2o_scsi_get_host(struct i2o_controller *c)
{
        return c->driver_data[i2o_scsi_driver.context];
};

/**
 *      i2o_scsi_remove - Remove I2O device from SCSI core
 *      @dev: device which should be removed
 *
 *      Removes the I2O device from the SCSI core again.
 *
 *      Returns 0 on success.
 */
static int i2o_scsi_remove(struct device *dev)
{
        struct i2o_device *i2o_dev = to_i2o_device(dev);
        struct i2o_controller *c = i2o_dev->iop;
        struct i2o_scsi_host *i2o_shost;
        struct scsi_device *scsi_dev;

        osm_info("device removed (TID: %03x)\n", i2o_dev->lct_data.tid);

        i2o_shost = i2o_scsi_get_host(c);

        shost_for_each_device(scsi_dev, i2o_shost->scsi_host)
            if (scsi_dev->hostdata == i2o_dev) {
                sysfs_remove_link(&i2o_dev->device.kobj, "scsi");
                scsi_remove_device(scsi_dev);
                scsi_device_put(scsi_dev);
                break;
        }

        return 0;
};

/**
 *      i2o_scsi_probe - verify if dev is a I2O SCSI device and install it
 *      @dev: device to verify if it is a I2O SCSI device
 *
 *      Retrieve channel, id and lun for I2O device. If everthing goes well
 *      register the I2O device as SCSI device on the I2O SCSI controller.
 *
 *      Returns 0 on success or negative error code on failure.
 */
static int i2o_scsi_probe(struct device *dev)
{
        struct i2o_device *i2o_dev = to_i2o_device(dev);
        struct i2o_controller *c = i2o_dev->iop;
        struct i2o_scsi_host *i2o_shost;
        struct Scsi_Host *scsi_host;
        struct i2o_device *parent;
        struct scsi_device *scsi_dev;
        u32 id = -1;
        u64 lun = -1;
        int channel = -1;
        int i, rc;

        i2o_shost = i2o_scsi_get_host(c);
        if (!i2o_shost)
                return -EFAULT;

        scsi_host = i2o_shost->scsi_host;

        switch (i2o_dev->lct_data.class_id) {
        case I2O_CLASS_RANDOM_BLOCK_STORAGE:
        case I2O_CLASS_EXECUTIVE:
#ifdef CONFIG_I2O_EXT_ADAPTEC
                if (c->adaptec) {
                        u8 type;
                        struct i2o_device *d = i2o_shost->channel[0];

                        if (!i2o_parm_field_get(d, 0x0000, 0, &type, 1)
                            && (type == 0x01))  /* SCSI bus */
                                if (!i2o_parm_field_get(d, 0x0200, 4, &id, 4)) {
                                        channel = 0;
                                        if (i2o_dev->lct_data.class_id ==
                                            I2O_CLASS_RANDOM_BLOCK_STORAGE)
                                                lun =
                                                    cpu_to_le64(i2o_shost->
                                                                lun++);
                                        else
                                                lun = 0;
                                }
                }
#endif
                break;

        case I2O_CLASS_SCSI_PERIPHERAL:
                if (i2o_parm_field_get(i2o_dev, 0x0000, 3, &id, 4))
                        return -EFAULT;

                if (i2o_parm_field_get(i2o_dev, 0x0000, 4, &lun, 8))
                        return -EFAULT;

                parent = i2o_iop_find_device(c, i2o_dev->lct_data.parent_tid);
                if (!parent) {
                        osm_warn("can not find parent of device %03x\n",
                                 i2o_dev->lct_data.tid);
                        return -EFAULT;
                }

                for (i = 0; i <= i2o_shost->scsi_host->max_channel; i++)
                        if (i2o_shost->channel[i] == parent)
                                channel = i;
                break;

        default:
                return -EFAULT;
        }

        if (channel == -1) {
                osm_warn("can not find channel of device %03x\n",
                         i2o_dev->lct_data.tid);
                return -EFAULT;
        }

        if (le32_to_cpu(id) >= scsi_host->max_id) {
                osm_warn("SCSI device id (%d) >= max_id of I2O host (%d)",
                         le32_to_cpu(id), scsi_host->max_id);
                return -EFAULT;
        }

        if (le64_to_cpu(lun) >= scsi_host->max_lun) {
                osm_warn("SCSI device lun (%lu) >= max_lun of I2O host (%d)",
                         (long unsigned int)le64_to_cpu(lun),
                         scsi_host->max_lun);
                return -EFAULT;
        }

        scsi_dev =
            __scsi_add_device(i2o_shost->scsi_host, channel, le32_to_cpu(id),
                              le64_to_cpu(lun), i2o_dev);

        if (IS_ERR(scsi_dev)) {
                osm_warn("can not add SCSI device %03x\n",
                         i2o_dev->lct_data.tid);
                return PTR_ERR(scsi_dev);
        }

        rc = sysfs_create_link(&i2o_dev->device.kobj,
                               &scsi_dev->sdev_gendev.kobj, "scsi");
        if (rc)
                goto err;

        osm_info("device added (TID: %03x) channel: %d, id: %d, lun: %ld\n",
                 i2o_dev->lct_data.tid, channel, le32_to_cpu(id),
                 (long unsigned int)le64_to_cpu(lun));

        return 0;

err:
        scsi_remove_device(scsi_dev);
        return rc;
};

static const char *i2o_scsi_info(struct Scsi_Host *SChost)
{
        struct i2o_scsi_host *hostdata;
        hostdata = (struct i2o_scsi_host *)SChost->hostdata;
        return hostdata->iop->name;
}

/**
 *      i2o_scsi_reply - SCSI OSM message reply handler
 *      @c: controller issuing the reply
 *      @m: message id for flushing
 *      @msg: the message from the controller
 *
 *      Process reply messages (interrupts in normal scsi controller think).
 *      We can get a variety of messages to process. The normal path is
 *      scsi command completions. We must also deal with IOP failures,
 *      the reply to a bus reset and the reply to a LUN query.
 *
 *      Returns 0 on success and if the reply should not be flushed or > 0
 *      on success and if the reply should be flushed. Returns negative error
 *      code on failure and if the reply should be flushed.
 */
static int i2o_scsi_reply(struct i2o_controller *c, u32 m,
                          struct i2o_message *msg)
{
        struct scsi_cmnd *cmd;
        u32 error;
        struct device *dev;

        cmd = i2o_cntxt_list_get(c, le32_to_cpu(msg->u.s.tcntxt));
        if (unlikely(!cmd)) {
                osm_err("NULL reply received!\n");
                return -1;
        }

        /*
         *      Low byte is device status, next is adapter status,
         *      (then one byte reserved), then request status.
         */
        error = le32_to_cpu(msg->body[0]);

        osm_debug("Completed %ld\n", cmd->serial_number);

        cmd->result = error & 0xff;
        /*
         * if DeviceStatus is not SCSI_SUCCESS copy over the sense data and let
         * the SCSI layer handle the error
         */
        if (cmd->result)
                memcpy(cmd->sense_buffer, &msg->body[3],
                       min(sizeof(cmd->sense_buffer), (size_t) 40));

        /* only output error code if AdapterStatus is not HBA_SUCCESS */
        if ((error >> 8) & 0xff)
                osm_err("SCSI error %08x\n", error);

        dev = &c->pdev->dev;

        scsi_dma_unmap(cmd);

        cmd->scsi_done(cmd);

        return 1;
};

/**
 *      i2o_scsi_notify_device_add - Retrieve notifications of added devices
 *      @i2o_dev: the I2O device which was added
 *
 *      If a I2O device is added we catch the notification, because I2O classes
 *      other then SCSI peripheral will not be received through
 *      i2o_scsi_probe().
 */
static void i2o_scsi_notify_device_add(struct i2o_device *i2o_dev)
{
        switch (i2o_dev->lct_data.class_id) {
        case I2O_CLASS_EXECUTIVE:
        case I2O_CLASS_RANDOM_BLOCK_STORAGE:
                i2o_scsi_probe(&i2o_dev->device);
                break;

        default:
                break;
        }
};

/**
 *      i2o_scsi_notify_device_remove - Retrieve notifications of removed devices
 *      @i2o_dev: the I2O device which was removed
 *
 *      If a I2O device is removed, we catch the notification to remove the
 *      corresponding SCSI device.
 */
static void i2o_scsi_notify_device_remove(struct i2o_device *i2o_dev)
{
        switch (i2o_dev->lct_data.class_id) {
        case I2O_CLASS_EXECUTIVE:
        case I2O_CLASS_RANDOM_BLOCK_STORAGE:
                i2o_scsi_remove(&i2o_dev->device);
                break;

        default:
                break;
        }
};

/**
 *      i2o_scsi_notify_controller_add - Retrieve notifications of added controllers
 *      @c: the controller which was added
 *
 *      If a I2O controller is added, we catch the notification to add a
 *      corresponding Scsi_Host.
 */
static void i2o_scsi_notify_controller_add(struct i2o_controller *c)
{
        struct i2o_scsi_host *i2o_shost;
        int rc;

        i2o_shost = i2o_scsi_host_alloc(c);
        if (IS_ERR(i2o_shost)) {
                osm_err("Could not initialize SCSI host\n");
                return;
        }

        rc = scsi_add_host(i2o_shost->scsi_host, &c->device);
        if (rc) {
                osm_err("Could not add SCSI host\n");
                scsi_host_put(i2o_shost->scsi_host);
                return;
        }

        c->driver_data[i2o_scsi_driver.context] = i2o_shost;

        osm_debug("new I2O SCSI host added\n");
};

/**
 *      i2o_scsi_notify_controller_remove - Retrieve notifications of removed controllers
 *      @c: the controller which was removed
 *
 *      If a I2O controller is removed, we catch the notification to remove the
 *      corresponding Scsi_Host.
 */
static void i2o_scsi_notify_controller_remove(struct i2o_controller *c)
{
        struct i2o_scsi_host *i2o_shost;
        i2o_shost = i2o_scsi_get_host(c);
        if (!i2o_shost)
                return;

        c->driver_data[i2o_scsi_driver.context] = NULL;

        scsi_remove_host(i2o_shost->scsi_host);
        scsi_host_put(i2o_shost->scsi_host);
        osm_debug("I2O SCSI host removed\n");
};

/* SCSI OSM driver struct */
static struct i2o_driver i2o_scsi_driver = {
        .name = OSM_NAME,
        .reply = i2o_scsi_reply,
        .classes = i2o_scsi_class_id,
        .notify_device_add = i2o_scsi_notify_device_add,
        .notify_device_remove = i2o_scsi_notify_device_remove,
        .notify_controller_add = i2o_scsi_notify_controller_add,
        .notify_controller_remove = i2o_scsi_notify_controller_remove,
        .driver = {
                   .probe = i2o_scsi_probe,
                   .remove = i2o_scsi_remove,
                   },
};

/**
 *      i2o_scsi_queuecommand - queue a SCSI command
 *      @SCpnt: scsi command pointer
 *      @done: callback for completion
 *
 *      Issue a scsi command asynchronously. Return 0 on success or 1 if
 *      we hit an error (normally message queue congestion). The only
 *      minor complication here is that I2O deals with the device addressing
 *      so we have to map the bus/dev/lun back to an I2O handle as well
 *      as faking absent devices ourself.
 *
 *      Locks: takes the controller lock on error path only
 */

static int i2o_scsi_queuecommand(struct scsi_cmnd *SCpnt,
                                 void (*done) (struct scsi_cmnd *))
{
        struct i2o_controller *c;
        struct i2o_device *i2o_dev;
        int tid;
        struct i2o_message *msg;
        /*
         * ENABLE_DISCONNECT
         * SIMPLE_TAG
         * RETURN_SENSE_DATA_IN_REPLY_MESSAGE_FRAME
         */
        u32 scsi_flags = 0x20a00000;
        u32 sgl_offset;
        u32 *mptr;
        u32 cmd = I2O_CMD_SCSI_EXEC << 24;
        int rc = 0;

        /*
         *      Do the incoming paperwork
         */
        i2o_dev = SCpnt->device->hostdata;
        c = i2o_dev->iop;

        SCpnt->scsi_done = done;

        if (unlikely(!i2o_dev)) {
                osm_warn("no I2O device in request\n");
                SCpnt->result = DID_NO_CONNECT << 16;
                done(SCpnt);
                goto exit;
        }

        tid = i2o_dev->lct_data.tid;

        osm_debug("qcmd: Tid = %03x\n", tid);
        osm_debug("Real scsi messages.\n");

        /*
         *      Put together a scsi execscb message
         */
        switch (SCpnt->sc_data_direction) {
        case PCI_DMA_NONE:
                /* DATA NO XFER */
                sgl_offset = SGL_OFFSET_0;
                break;

        case PCI_DMA_TODEVICE:
                /* DATA OUT (iop-->dev) */
                scsi_flags |= 0x80000000;
                sgl_offset = SGL_OFFSET_10;
                break;

        case PCI_DMA_FROMDEVICE:
                /* DATA IN  (iop<--dev) */
                scsi_flags |= 0x40000000;
                sgl_offset = SGL_OFFSET_10;
                break;

        default:
                /* Unknown - kill the command */
                SCpnt->result = DID_NO_CONNECT << 16;
                done(SCpnt);
                goto exit;
        }

        /*
         *      Obtain an I2O message. If there are none free then
         *      throw it back to the scsi layer
         */

        msg = i2o_msg_get(c);
        if (IS_ERR(msg)) {
                rc = SCSI_MLQUEUE_HOST_BUSY;
                goto exit;
        }

        mptr = &msg->body[0];

#if 0 /* this code can't work */
#ifdef CONFIG_I2O_EXT_ADAPTEC
        if (c->adaptec) {
                u32 adpt_flags = 0;

                if (SCpnt->sc_request && SCpnt->sc_request->upper_private_data) {
                        i2o_sg_io_hdr_t __user *usr_ptr =
                            ((Sg_request *) (SCpnt->sc_request->
                                             upper_private_data))->header.
                            usr_ptr;

                        if (usr_ptr)
                                get_user(adpt_flags, &usr_ptr->flags);
                }

                switch (i2o_dev->lct_data.class_id) {
                case I2O_CLASS_EXECUTIVE:
                case I2O_CLASS_RANDOM_BLOCK_STORAGE:
                        /* interpret flag has to be set for executive */
                        adpt_flags ^= I2O_DPT_SG_FLAG_INTERPRET;
                        break;

                default:
                        break;
                }

                /*
                 * for Adaptec controllers we use the PRIVATE command, because
                 * the normal SCSI EXEC doesn't support all SCSI commands on
                 * all controllers (for example READ CAPACITY).
                 */
                if (sgl_offset == SGL_OFFSET_10)
                        sgl_offset = SGL_OFFSET_12;
                cmd = I2O_CMD_PRIVATE << 24;
                *mptr++ = cpu_to_le32(I2O_VENDOR_DPT << 16 | I2O_CMD_SCSI_EXEC);
                *mptr++ = cpu_to_le32(adpt_flags | tid);
        }
#endif
#endif

        msg->u.head[1] = cpu_to_le32(cmd | HOST_TID << 12 | tid);
        msg->u.s.icntxt = cpu_to_le32(i2o_scsi_driver.context);

        /* We want the SCSI control block back */
        msg->u.s.tcntxt = cpu_to_le32(i2o_cntxt_list_add(c, SCpnt));

        /* 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)
         */

        /* Attach tags to the devices */
        /* FIXME: implement
           if(SCpnt->device->tagged_supported) {
           if(SCpnt->tag == HEAD_OF_QUEUE_TAG)
           scsi_flags |= 0x01000000;
           else if(SCpnt->tag == ORDERED_QUEUE_TAG)
           scsi_flags |= 0x01800000;
           }
         */

        *mptr++ = cpu_to_le32(scsi_flags | SCpnt->cmd_len);

        /* Write SCSI command into the message - always 16 byte block */
        memcpy(mptr, SCpnt->cmnd, 16);
        mptr += 4;

        if (sgl_offset != SGL_OFFSET_0) {
                /* write size of data addressed by SGL */
                *mptr++ = cpu_to_le32(scsi_bufflen(SCpnt));

                /* Now fill in the SGList and command */

                if (scsi_sg_count(SCpnt)) {
                        if (!i2o_dma_map_sg(c, scsi_sglist(SCpnt),
                                            scsi_sg_count(SCpnt),
                                            SCpnt->sc_data_direction, &mptr))
                                goto nomem;
                }
        }

        /* Stick the headers on */
        msg->u.head[0] =
            cpu_to_le32(I2O_MESSAGE_SIZE(mptr - &msg->u.head[0]) | sgl_offset);

        /* Queue the message */
        i2o_msg_post(c, msg);

        osm_debug("Issued %ld\n", SCpnt->serial_number);

        return 0;

      nomem:
        rc = -ENOMEM;
        i2o_msg_nop(c, msg);

      exit:
        return rc;
};

/**
 *      i2o_scsi_abort - abort a running command
 *      @SCpnt: command to abort
 *
 *      Ask the I2O controller to abort a command. This is an asynchrnous
 *      process and our callback handler will see the command complete with an
 *      aborted message if it succeeds.
 *
 *      Returns 0 if the command is successfully aborted or negative error code
 *      on failure.
 */
static int i2o_scsi_abort(struct scsi_cmnd *SCpnt)
{
        struct i2o_device *i2o_dev;
        struct i2o_controller *c;
        struct i2o_message *msg;
        int tid;
        int status = FAILED;

        osm_warn("Aborting command block.\n");

        i2o_dev = SCpnt->device->hostdata;
        c = i2o_dev->iop;
        tid = i2o_dev->lct_data.tid;

        msg = i2o_msg_get_wait(c, I2O_TIMEOUT_MESSAGE_GET);
        if (IS_ERR(msg))
                return SCSI_MLQUEUE_HOST_BUSY;

        msg->u.head[0] = cpu_to_le32(FIVE_WORD_MSG_SIZE | SGL_OFFSET_0);
        msg->u.head[1] =
            cpu_to_le32(I2O_CMD_SCSI_ABORT << 24 | HOST_TID << 12 | tid);
        msg->body[0] = cpu_to_le32(i2o_cntxt_list_get_ptr(c, SCpnt));

        if (!i2o_msg_post_wait(c, msg, I2O_TIMEOUT_SCSI_SCB_ABORT))
                status = SUCCESS;

        return status;
}

/**
 *      i2o_scsi_bios_param     -       Invent disk geometry
 *      @sdev: scsi device
 *      @dev: block layer device
 *      @capacity: size in sectors
 *      @ip: geometry array
 *
 *      This is anyone's guess quite frankly. We use the same rules everyone
 *      else appears to and hope. It seems to work.
 */

static int i2o_scsi_bios_param(struct scsi_device *sdev,
                               struct block_device *dev, sector_t capacity,
                               int *ip)
{
        int size;

        size = 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;
}

static struct scsi_host_template i2o_scsi_host_template = {
        .proc_name = OSM_NAME,
        .name = OSM_DESCRIPTION,
        .info = i2o_scsi_info,
        .queuecommand = i2o_scsi_queuecommand,
        .eh_abort_handler = i2o_scsi_abort,
        .bios_param = i2o_scsi_bios_param,
        .can_queue = I2O_SCSI_CAN_QUEUE,
        .sg_tablesize = 8,
        .cmd_per_lun = 6,
        .use_clustering = ENABLE_CLUSTERING,
};

/**
 *      i2o_scsi_init - SCSI OSM initialization function
 *
 *      Register SCSI OSM into I2O core.
 *
 *      Returns 0 on success or negative error code on failure.
 */
static int __init i2o_scsi_init(void)
{
        int rc;

        printk(KERN_INFO OSM_DESCRIPTION " v" OSM_VERSION "\n");

        /* Register SCSI OSM into I2O core */
        rc = i2o_driver_register(&i2o_scsi_driver);
        if (rc) {
                osm_err("Could not register SCSI driver\n");
                return rc;
        }

        return 0;
};

/**
 *      i2o_scsi_exit - SCSI OSM exit function
 *
 *      Unregisters SCSI OSM from I2O core.
 */
static void __exit i2o_scsi_exit(void)
{
        /* Unregister I2O SCSI OSM from I2O core */
        i2o_driver_unregister(&i2o_scsi_driver);
};

MODULE_AUTHOR("Red Hat Software");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION(OSM_DESCRIPTION);
MODULE_VERSION(OSM_VERSION);

module_init(i2o_scsi_init);
module_exit(i2o_scsi_exit);