// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 *                      Linux MegaRAID device driver
 *
 * Copyright (c) 2003-2004  LSI Logic Corporation.
 *
 * FILE         : megaraid_mbox.c
 * Version      : v2.20.5.1 (Nov 16 2006)
 *
 * Authors:
 *      Atul Mukker             <Atul.Mukker@lsi.com>
 *      Sreenivas Bagalkote     <Sreenivas.Bagalkote@lsi.com>
 *      Manoj Jose              <Manoj.Jose@lsi.com>
 *      Seokmann Ju
 *
 * List of supported controllers
 *
 * OEM  Product Name                    VID     DID     SSVID   SSID
 * ---  ------------                    ---     ---     ----    ----
 * Dell PERC3/QC                        101E    1960    1028    0471
 * Dell PERC3/DC                        101E    1960    1028    0493
 * Dell PERC3/SC                        101E    1960    1028    0475
 * Dell PERC3/Di                        1028    1960    1028    0123
 * Dell PERC4/SC                        1000    1960    1028    0520
 * Dell PERC4/DC                        1000    1960    1028    0518
 * Dell PERC4/QC                        1000    0407    1028    0531
 * Dell PERC4/Di                        1028    000F    1028    014A
 * Dell PERC 4e/Si                      1028    0013    1028    016c
 * Dell PERC 4e/Di                      1028    0013    1028    016d
 * Dell PERC 4e/Di                      1028    0013    1028    016e
 * Dell PERC 4e/Di                      1028    0013    1028    016f
 * Dell PERC 4e/Di                      1028    0013    1028    0170
 * Dell PERC 4e/DC                      1000    0408    1028    0002
 * Dell PERC 4e/SC                      1000    0408    1028    0001
 *
 * LSI MegaRAID SCSI 320-0              1000    1960    1000    A520
 * LSI MegaRAID SCSI 320-1              1000    1960    1000    0520
 * LSI MegaRAID SCSI 320-2              1000    1960    1000    0518
 * LSI MegaRAID SCSI 320-0X             1000    0407    1000    0530
 * LSI MegaRAID SCSI 320-2X             1000    0407    1000    0532
 * LSI MegaRAID SCSI 320-4X             1000    0407    1000    0531
 * LSI MegaRAID SCSI 320-1E             1000    0408    1000    0001
 * LSI MegaRAID SCSI 320-2E             1000    0408    1000    0002
 * LSI MegaRAID SATA 150-4              1000    1960    1000    4523
 * LSI MegaRAID SATA 150-6              1000    1960    1000    0523
 * LSI MegaRAID SATA 300-4X             1000    0409    1000    3004
 * LSI MegaRAID SATA 300-8X             1000    0409    1000    3008
 *
 * INTEL RAID Controller SRCU42X        1000    0407    8086    0532
 * INTEL RAID Controller SRCS16         1000    1960    8086    0523
 * INTEL RAID Controller SRCU42E        1000    0408    8086    0002
 * INTEL RAID Controller SRCZCRX        1000    0407    8086    0530
 * INTEL RAID Controller SRCS28X        1000    0409    8086    3008
 * INTEL RAID Controller SROMBU42E      1000    0408    8086    3431
 * INTEL RAID Controller SROMBU42E      1000    0408    8086    3499
 * INTEL RAID Controller SRCU51L        1000    1960    8086    0520
 *
 * FSC  MegaRAID PCI Express ROMB       1000    0408    1734    1065
 *
 * ACER MegaRAID ROMB-2E                1000    0408    1025    004D
 *
 * NEC  MegaRAID PCI Express ROMB       1000    0408    1033    8287
 *
 * For history of changes, see Documentation/scsi/ChangeLog.megaraid
 */

#include <linux/slab.h>
#include <linux/module.h>
#include "megaraid_mbox.h"

static int megaraid_init(void);
static void megaraid_exit(void);

static int megaraid_probe_one(struct pci_dev*, const struct pci_device_id *);
static void megaraid_detach_one(struct pci_dev *);
static void megaraid_mbox_shutdown(struct pci_dev *);

static int megaraid_io_attach(adapter_t *);
static void megaraid_io_detach(adapter_t *);

static int megaraid_init_mbox(adapter_t *);
static void megaraid_fini_mbox(adapter_t *);

static int megaraid_alloc_cmd_packets(adapter_t *);
static void megaraid_free_cmd_packets(adapter_t *);

static int megaraid_mbox_setup_dma_pools(adapter_t *);
static void megaraid_mbox_teardown_dma_pools(adapter_t *);

static int megaraid_sysfs_alloc_resources(adapter_t *);
static void megaraid_sysfs_free_resources(adapter_t *);

static int megaraid_abort_handler(struct scsi_cmnd *);
static int megaraid_reset_handler(struct scsi_cmnd *);

static int mbox_post_sync_cmd(adapter_t *, uint8_t []);
static int mbox_post_sync_cmd_fast(adapter_t *, uint8_t []);
static int megaraid_busywait_mbox(mraid_device_t *);
static int megaraid_mbox_product_info(adapter_t *);
static int megaraid_mbox_extended_cdb(adapter_t *);
static int megaraid_mbox_support_ha(adapter_t *, uint16_t *);
static int megaraid_mbox_support_random_del(adapter_t *);
static int megaraid_mbox_get_max_sg(adapter_t *);
static void megaraid_mbox_enum_raid_scsi(adapter_t *);
static void megaraid_mbox_flush_cache(adapter_t *);
static int megaraid_mbox_fire_sync_cmd(adapter_t *);

static void megaraid_mbox_display_scb(adapter_t *, scb_t *);
static void megaraid_mbox_setup_device_map(adapter_t *);

static int megaraid_queue_command(struct Scsi_Host *, struct scsi_cmnd *);
static scb_t *megaraid_mbox_build_cmd(adapter_t *, struct scsi_cmnd *, int *);
static void megaraid_mbox_runpendq(adapter_t *, scb_t *);
static void megaraid_mbox_prepare_pthru(adapter_t *, scb_t *,
                struct scsi_cmnd *);
static void megaraid_mbox_prepare_epthru(adapter_t *, scb_t *,
                struct scsi_cmnd *);

static irqreturn_t megaraid_isr(int, void *);

static void megaraid_mbox_dpc(unsigned long);

static ssize_t megaraid_mbox_app_hndl_show(struct device *, struct device_attribute *attr, char *);
static ssize_t megaraid_mbox_ld_show(struct device *, struct device_attribute *attr, char *);

static int megaraid_cmm_register(adapter_t *);
static int megaraid_cmm_unregister(adapter_t *);
static int megaraid_mbox_mm_handler(unsigned long, uioc_t *, uint32_t);
static int megaraid_mbox_mm_command(adapter_t *, uioc_t *);
static void megaraid_mbox_mm_done(adapter_t *, scb_t *);
static int gather_hbainfo(adapter_t *, mraid_hba_info_t *);
static int wait_till_fw_empty(adapter_t *);



MODULE_AUTHOR("megaraidlinux@lsi.com");
MODULE_DESCRIPTION("LSI Logic MegaRAID Mailbox Driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(MEGARAID_VERSION);

/*
 * ### modules parameters for driver ###
 */

/*
 * Set to enable driver to expose unconfigured disk to kernel
 */
static int megaraid_expose_unconf_disks = 0;
module_param_named(unconf_disks, megaraid_expose_unconf_disks, int, 0);
MODULE_PARM_DESC(unconf_disks,
        "Set to expose unconfigured disks to kernel (default=0)");

/*
 * driver wait time if the adapter's mailbox is busy
 */
static unsigned int max_mbox_busy_wait = MBOX_BUSY_WAIT;
module_param_named(busy_wait, max_mbox_busy_wait, int, 0);
MODULE_PARM_DESC(busy_wait,
        "Max wait for mailbox in microseconds if busy (default=10)");

/*
 * number of sectors per IO command
 */
static unsigned int megaraid_max_sectors = MBOX_MAX_SECTORS;
module_param_named(max_sectors, megaraid_max_sectors, int, 0);
MODULE_PARM_DESC(max_sectors,
        "Maximum number of sectors per IO command (default=128)");

/*
 * number of commands per logical unit
 */
static unsigned int megaraid_cmd_per_lun = MBOX_DEF_CMD_PER_LUN;
module_param_named(cmd_per_lun, megaraid_cmd_per_lun, int, 0);
MODULE_PARM_DESC(cmd_per_lun,
        "Maximum number of commands per logical unit (default=64)");


/*
 * Fast driver load option, skip scanning for physical devices during load.
 * This would result in non-disk devices being skipped during driver load
 * time. These can be later added though, using /proc/scsi/scsi
 */
static unsigned int megaraid_fast_load = 0;
module_param_named(fast_load, megaraid_fast_load, int, 0);
MODULE_PARM_DESC(fast_load,
        "Faster loading of the driver, skips physical devices! (default=0)");


/*
 * mraid_debug level - threshold for amount of information to be displayed by
 * the driver. This level can be changed through modules parameters, ioctl or
 * sysfs/proc interface. By default, print the announcement messages only.
 */
int mraid_debug_level = CL_ANN;
module_param_named(debug_level, mraid_debug_level, int, 0);
MODULE_PARM_DESC(debug_level, "Debug level for driver (default=0)");

/*
 * PCI table for all supported controllers.
 */
static struct pci_device_id pci_id_table_g[] =  {
        {
                PCI_VENDOR_ID_DELL,
                PCI_DEVICE_ID_PERC4_DI_DISCOVERY,
                PCI_VENDOR_ID_DELL,
                PCI_SUBSYS_ID_PERC4_DI_DISCOVERY,
        },
        {
                PCI_VENDOR_ID_LSI_LOGIC,
                PCI_DEVICE_ID_PERC4_SC,
                PCI_VENDOR_ID_DELL,
                PCI_SUBSYS_ID_PERC4_SC,
        },
        {
                PCI_VENDOR_ID_LSI_LOGIC,
                PCI_DEVICE_ID_PERC4_DC,
                PCI_VENDOR_ID_DELL,
                PCI_SUBSYS_ID_PERC4_DC,
        },
        {
                PCI_VENDOR_ID_LSI_LOGIC,
                PCI_DEVICE_ID_VERDE,
                PCI_ANY_ID,
                PCI_ANY_ID,
        },
        {
                PCI_VENDOR_ID_DELL,
                PCI_DEVICE_ID_PERC4_DI_EVERGLADES,
                PCI_VENDOR_ID_DELL,
                PCI_SUBSYS_ID_PERC4_DI_EVERGLADES,
        },
        {
                PCI_VENDOR_ID_DELL,
                PCI_DEVICE_ID_PERC4E_SI_BIGBEND,
                PCI_VENDOR_ID_DELL,
                PCI_SUBSYS_ID_PERC4E_SI_BIGBEND,
        },
        {
                PCI_VENDOR_ID_DELL,
                PCI_DEVICE_ID_PERC4E_DI_KOBUK,
                PCI_VENDOR_ID_DELL,
                PCI_SUBSYS_ID_PERC4E_DI_KOBUK,
        },
        {
                PCI_VENDOR_ID_DELL,
                PCI_DEVICE_ID_PERC4E_DI_CORVETTE,
                PCI_VENDOR_ID_DELL,
                PCI_SUBSYS_ID_PERC4E_DI_CORVETTE,
        },
        {
                PCI_VENDOR_ID_DELL,
                PCI_DEVICE_ID_PERC4E_DI_EXPEDITION,
                PCI_VENDOR_ID_DELL,
                PCI_SUBSYS_ID_PERC4E_DI_EXPEDITION,
        },
        {
                PCI_VENDOR_ID_DELL,
                PCI_DEVICE_ID_PERC4E_DI_GUADALUPE,
                PCI_VENDOR_ID_DELL,
                PCI_SUBSYS_ID_PERC4E_DI_GUADALUPE,
        },
        {
                PCI_VENDOR_ID_LSI_LOGIC,
                PCI_DEVICE_ID_DOBSON,
                PCI_ANY_ID,
                PCI_ANY_ID,
        },
        {
                PCI_VENDOR_ID_AMI,
                PCI_DEVICE_ID_AMI_MEGARAID3,
                PCI_ANY_ID,
                PCI_ANY_ID,
        },
        {
                PCI_VENDOR_ID_LSI_LOGIC,
                PCI_DEVICE_ID_AMI_MEGARAID3,
                PCI_ANY_ID,
                PCI_ANY_ID,
        },
        {
                PCI_VENDOR_ID_LSI_LOGIC,
                PCI_DEVICE_ID_LINDSAY,
                PCI_ANY_ID,
                PCI_ANY_ID,
        },
        {0}     /* Terminating entry */
};
MODULE_DEVICE_TABLE(pci, pci_id_table_g);


static struct pci_driver megaraid_pci_driver = {
        .name           = "megaraid",
        .id_table       = pci_id_table_g,
        .probe          = megaraid_probe_one,
        .remove         = megaraid_detach_one,
        .shutdown       = megaraid_mbox_shutdown,
};



// definitions for the device attributes for exporting logical drive number
// for a scsi address (Host, Channel, Id, Lun)

static DEVICE_ATTR_ADMIN_RO(megaraid_mbox_app_hndl);

// Host template initializer for megaraid mbox sysfs device attributes
static struct device_attribute *megaraid_shost_attrs[] = {
        &dev_attr_megaraid_mbox_app_hndl,
        NULL,
};


static DEVICE_ATTR_ADMIN_RO(megaraid_mbox_ld);

// Host template initializer for megaraid mbox sysfs device attributes
static struct device_attribute *megaraid_sdev_attrs[] = {
        &dev_attr_megaraid_mbox_ld,
        NULL,
};

/*
 * Scsi host template for megaraid unified driver
 */
static struct scsi_host_template megaraid_template_g = {
        .module                         = THIS_MODULE,
        .name                           = "LSI Logic MegaRAID driver",
        .proc_name                      = "megaraid",
        .queuecommand                   = megaraid_queue_command,
        .eh_abort_handler               = megaraid_abort_handler,
        .eh_host_reset_handler          = megaraid_reset_handler,
        .change_queue_depth             = scsi_change_queue_depth,
        .no_write_same                  = 1,
        .sdev_attrs                     = megaraid_sdev_attrs,
        .shost_attrs                    = megaraid_shost_attrs,
};


/**
 * megaraid_init - module load hook
 *
 * We register ourselves as hotplug enabled module and let PCI subsystem
 * discover our adapters.
 */
static int __init
megaraid_init(void)
{
        int     rval;

        // Announce the driver version
        con_log(CL_ANN, (KERN_INFO "megaraid: %s %s\n", MEGARAID_VERSION,
                MEGARAID_EXT_VERSION));

        // check validity of module parameters
        if (megaraid_cmd_per_lun > MBOX_MAX_SCSI_CMDS) {

                con_log(CL_ANN, (KERN_WARNING
                        "megaraid mailbox: max commands per lun reset to %d\n",
                        MBOX_MAX_SCSI_CMDS));

                megaraid_cmd_per_lun = MBOX_MAX_SCSI_CMDS;
        }


        // register as a PCI hot-plug driver module
        rval = pci_register_driver(&megaraid_pci_driver);
        if (rval < 0) {
                con_log(CL_ANN, (KERN_WARNING
                        "megaraid: could not register hotplug support.\n"));
        }

        return rval;
}


/**
 * megaraid_exit - driver unload entry point
 *
 * We simply unwrap the megaraid_init routine here.
 */
static void __exit
megaraid_exit(void)
{
        con_log(CL_DLEVEL1, (KERN_NOTICE "megaraid: unloading framework\n"));

        // unregister as PCI hotplug driver
        pci_unregister_driver(&megaraid_pci_driver);

        return;
}


/**
 * megaraid_probe_one - PCI hotplug entry point
 * @pdev        : handle to this controller's PCI configuration space
 * @id          : pci device id of the class of controllers
 *
 * This routine should be called whenever a new adapter is detected by the
 * PCI hotplug susbsystem.
 */
static int
megaraid_probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
{
        adapter_t       *adapter;


        // detected a new controller
        con_log(CL_ANN, (KERN_INFO
                "megaraid: probe new device %#4.04x:%#4.04x:%#4.04x:%#4.04x: ",
                pdev->vendor, pdev->device, pdev->subsystem_vendor,
                pdev->subsystem_device));

        con_log(CL_ANN, ("bus %d:slot %d:func %d\n", pdev->bus->number,
                PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn)));

        if (pci_enable_device(pdev)) {
                con_log(CL_ANN, (KERN_WARNING
                                "megaraid: pci_enable_device failed\n"));

                return -ENODEV;
        }

        // Enable bus-mastering on this controller
        pci_set_master(pdev);

        // Allocate the per driver initialization structure
        adapter = kzalloc(sizeof(adapter_t), GFP_KERNEL);

        if (adapter == NULL) {
                con_log(CL_ANN, (KERN_WARNING
                "megaraid: out of memory, %s %d.\n", __func__, __LINE__));

                goto out_probe_one;
        }


        // set up PCI related soft state and other pre-known parameters
        adapter->unique_id      = pdev->bus->number << 8 | pdev->devfn;
        adapter->irq            = pdev->irq;
        adapter->pdev           = pdev;

        atomic_set(&adapter->being_detached, 0);

        // Setup the default DMA mask. This would be changed later on
        // depending on hardware capabilities
        if (dma_set_mask(&adapter->pdev->dev, DMA_BIT_MASK(32))) {
                con_log(CL_ANN, (KERN_WARNING
                        "megaraid: dma_set_mask failed:%d\n", __LINE__));

                goto out_free_adapter;
        }


        // Initialize the synchronization lock for kernel and LLD
        spin_lock_init(&adapter->lock);

        // Initialize the command queues: the list of free SCBs and the list
        // of pending SCBs.
        INIT_LIST_HEAD(&adapter->kscb_pool);
        spin_lock_init(SCSI_FREE_LIST_LOCK(adapter));

        INIT_LIST_HEAD(&adapter->pend_list);
        spin_lock_init(PENDING_LIST_LOCK(adapter));

        INIT_LIST_HEAD(&adapter->completed_list);
        spin_lock_init(COMPLETED_LIST_LOCK(adapter));


        // Start the mailbox based controller
        if (megaraid_init_mbox(adapter) != 0) {
                con_log(CL_ANN, (KERN_WARNING
                        "megaraid: mailbox adapter did not initialize\n"));

                goto out_free_adapter;
        }

        // Register with LSI Common Management Module
        if (megaraid_cmm_register(adapter) != 0) {

                con_log(CL_ANN, (KERN_WARNING
                "megaraid: could not register with management module\n"));

                goto out_fini_mbox;
        }

        // setup adapter handle in PCI soft state
        pci_set_drvdata(pdev, adapter);

        // attach with scsi mid-layer
        if (megaraid_io_attach(adapter) != 0) {

                con_log(CL_ANN, (KERN_WARNING "megaraid: io attach failed\n"));

                goto out_cmm_unreg;
        }

        return 0;

out_cmm_unreg:
        megaraid_cmm_unregister(adapter);
out_fini_mbox:
        megaraid_fini_mbox(adapter);
out_free_adapter:
        kfree(adapter);
out_probe_one:
        pci_disable_device(pdev);

        return -ENODEV;
}


/**
 * megaraid_detach_one - release framework resources and call LLD release routine
 * @pdev        : handle for our PCI configuration space
 *
 * This routine is called during driver unload. We free all the allocated
 * resources and call the corresponding LLD so that it can also release all
 * its resources.
 *
 * This routine is also called from the PCI hotplug system.
 */
static void
megaraid_detach_one(struct pci_dev *pdev)
{
        adapter_t               *adapter;
        struct Scsi_Host        *host;


        // Start a rollback on this adapter
        adapter = pci_get_drvdata(pdev);

        if (!adapter) {
                con_log(CL_ANN, (KERN_CRIT
                "megaraid: Invalid detach on %#4.04x:%#4.04x:%#4.04x:%#4.04x\n",
                        pdev->vendor, pdev->device, pdev->subsystem_vendor,
                        pdev->subsystem_device));

                return;
        }
        else {
                con_log(CL_ANN, (KERN_NOTICE
                "megaraid: detaching device %#4.04x:%#4.04x:%#4.04x:%#4.04x\n",
                        pdev->vendor, pdev->device, pdev->subsystem_vendor,
                        pdev->subsystem_device));
        }


        host = adapter->host;

        // do not allow any more requests from the management module for this
        // adapter.
        // FIXME: How do we account for the request which might still be
        // pending with us?
        atomic_set(&adapter->being_detached, 1);

        // detach from the IO sub-system
        megaraid_io_detach(adapter);

        // Unregister from common management module
        //
        // FIXME: this must return success or failure for conditions if there
        // is a command pending with LLD or not.
        megaraid_cmm_unregister(adapter);

        // finalize the mailbox based controller and release all resources
        megaraid_fini_mbox(adapter);

        kfree(adapter);

        scsi_host_put(host);

        pci_disable_device(pdev);

        return;
}


/**
 * megaraid_mbox_shutdown - PCI shutdown for megaraid HBA
 * @pdev                : generic driver model device
 *
 * Shutdown notification, perform flush cache.
 */
static void
megaraid_mbox_shutdown(struct pci_dev *pdev)
{
        adapter_t               *adapter = pci_get_drvdata(pdev);
        static int              counter;

        if (!adapter) {
                con_log(CL_ANN, (KERN_WARNING
                        "megaraid: null device in shutdown\n"));
                return;
        }

        // flush caches now
        con_log(CL_ANN, (KERN_INFO "megaraid: flushing adapter %d...",
                counter++));

        megaraid_mbox_flush_cache(adapter);

        con_log(CL_ANN, ("done\n"));
}


/**
 * megaraid_io_attach - attach a device with the IO subsystem
 * @adapter             : controller's soft state
 *
 * Attach this device with the IO subsystem.
 */
static int
megaraid_io_attach(adapter_t *adapter)
{
        struct Scsi_Host        *host;

        // Initialize SCSI Host structure
        host = scsi_host_alloc(&megaraid_template_g, 8);
        if (!host) {
                con_log(CL_ANN, (KERN_WARNING
                        "megaraid mbox: scsi_register failed\n"));

                return -1;
        }

        SCSIHOST2ADAP(host)     = (caddr_t)adapter;
        adapter->host           = host;

        host->irq               = adapter->irq;
        host->unique_id         = adapter->unique_id;
        host->can_queue         = adapter->max_cmds;
        host->this_id           = adapter->init_id;
        host->sg_tablesize      = adapter->sglen;
        host->max_sectors       = adapter->max_sectors;
        host->cmd_per_lun       = adapter->cmd_per_lun;
        host->max_channel       = adapter->max_channel;
        host->max_id            = adapter->max_target;
        host->max_lun           = adapter->max_lun;


        // notify mid-layer about the new controller
        if (scsi_add_host(host, &adapter->pdev->dev)) {

                con_log(CL_ANN, (KERN_WARNING
                        "megaraid mbox: scsi_add_host failed\n"));

                scsi_host_put(host);

                return -1;
        }

        scsi_scan_host(host);

        return 0;
}


/**
 * megaraid_io_detach - detach a device from the IO subsystem
 * @adapter             : controller's soft state
 *
 * Detach this device from the IO subsystem.
 */
static void
megaraid_io_detach(adapter_t *adapter)
{
        struct Scsi_Host        *host;

        con_log(CL_DLEVEL1, (KERN_INFO "megaraid: io detach\n"));

        host = adapter->host;

        scsi_remove_host(host);

        return;
}


/*
 * START: Mailbox Low Level Driver
 *
 * This is section specific to the single mailbox based controllers
 */

/**
 * megaraid_init_mbox - initialize controller
 * @adapter             : our soft state
 *
 * - Allocate 16-byte aligned mailbox memory for firmware handshake
 * - Allocate controller's memory resources
 * - Find out all initialization data
 * - Allocate memory required for all the commands
 * - Use internal library of FW routines, build up complete soft state
 */
static int
megaraid_init_mbox(adapter_t *adapter)
{
        struct pci_dev          *pdev;
        mraid_device_t          *raid_dev;
        int                     i;
        uint32_t                magic64;


        adapter->ito    = MBOX_TIMEOUT;
        pdev            = adapter->pdev;

        /*
         * Allocate and initialize the init data structure for mailbox
         * controllers
         */
        raid_dev = kzalloc(sizeof(mraid_device_t), GFP_KERNEL);
        if (raid_dev == NULL) return -1;


        /*
         * Attach the adapter soft state to raid device soft state
         */
        adapter->raid_device    = (caddr_t)raid_dev;
        raid_dev->fast_load     = megaraid_fast_load;


        // our baseport
        raid_dev->baseport = pci_resource_start(pdev, 0);

        if (pci_request_regions(pdev, "MegaRAID: LSI Logic Corporation") != 0) {

                con_log(CL_ANN, (KERN_WARNING
                                "megaraid: mem region busy\n"));

                goto out_free_raid_dev;
        }

        raid_dev->baseaddr = ioremap(raid_dev->baseport, 128);

        if (!raid_dev->baseaddr) {

                con_log(CL_ANN, (KERN_WARNING
                        "megaraid: could not map hba memory\n") );

                goto out_release_regions;
        }

        /* initialize the mutual exclusion lock for the mailbox */
        spin_lock_init(&raid_dev->mailbox_lock);

        /* allocate memory required for commands */
        if (megaraid_alloc_cmd_packets(adapter) != 0)
                goto out_iounmap;

        /*
         * Issue SYNC cmd to flush the pending cmds in the adapter
         * and initialize its internal state
         */

        if (megaraid_mbox_fire_sync_cmd(adapter))
                con_log(CL_ANN, ("megaraid: sync cmd failed\n"));

        /*
         * Setup the rest of the soft state using the library of
         * FW routines
         */

        /* request IRQ and register the interrupt service routine */
        if (request_irq(adapter->irq, megaraid_isr, IRQF_SHARED, "megaraid",
                adapter)) {

                con_log(CL_ANN, (KERN_WARNING
                        "megaraid: Couldn't register IRQ %d!\n", adapter->irq));
                goto out_alloc_cmds;

        }

        // Product info
        if (megaraid_mbox_product_info(adapter) != 0)
                goto out_free_irq;

        // Do we support extended CDBs
        adapter->max_cdb_sz = 10;
        if (megaraid_mbox_extended_cdb(adapter) == 0) {
                adapter->max_cdb_sz = 16;
        }

        /*
         * Do we support cluster environment, if we do, what is the initiator
         * id.
         * NOTE: In a non-cluster aware firmware environment, the LLD should
         * return 7 as initiator id.
         */
        adapter->ha             = 0;
        adapter->init_id        = -1;
        if (megaraid_mbox_support_ha(adapter, &adapter->init_id) == 0) {
                adapter->ha = 1;
        }

        /*
         * Prepare the device ids array to have the mapping between the kernel
         * device address and megaraid device address.
         * We export the physical devices on their actual addresses. The
         * logical drives are exported on a virtual SCSI channel
         */
        megaraid_mbox_setup_device_map(adapter);

        // If the firmware supports random deletion, update the device id map
        if (megaraid_mbox_support_random_del(adapter)) {

                // Change the logical drives numbers in device_ids array one
                // slot in device_ids is reserved for target id, that's why
                // "<=" below
                for (i = 0; i <= MAX_LOGICAL_DRIVES_40LD; i++) {
                        adapter->device_ids[adapter->max_channel][i] += 0x80;
                }
                adapter->device_ids[adapter->max_channel][adapter->init_id] =
                        0xFF;

                raid_dev->random_del_supported = 1;
        }

        /*
         * find out the maximum number of scatter-gather elements supported by
         * this firmware
         */
        adapter->sglen = megaraid_mbox_get_max_sg(adapter);

        // enumerate RAID and SCSI channels so that all devices on SCSI
        // channels can later be exported, including disk devices
        megaraid_mbox_enum_raid_scsi(adapter);

        /*
         * Other parameters required by upper layer
         *
         * maximum number of sectors per IO command
         */
        adapter->max_sectors = megaraid_max_sectors;

        /*
         * number of queued commands per LUN.
         */
        adapter->cmd_per_lun = megaraid_cmd_per_lun;

        /*
         * Allocate resources required to issue FW calls, when sysfs is
         * accessed
         */
        if (megaraid_sysfs_alloc_resources(adapter) != 0)
                goto out_free_irq;

        // Set the DMA mask to 64-bit. All supported controllers as capable of
        // DMA in this range
        pci_read_config_dword(adapter->pdev, PCI_CONF_AMISIG64, &magic64);

        if (((magic64 == HBA_SIGNATURE_64_BIT) &&
                ((adapter->pdev->subsystem_device !=
                PCI_SUBSYS_ID_MEGARAID_SATA_150_6) &&
                (adapter->pdev->subsystem_device !=
                PCI_SUBSYS_ID_MEGARAID_SATA_150_4))) ||
                (adapter->pdev->vendor == PCI_VENDOR_ID_LSI_LOGIC &&
                adapter->pdev->device == PCI_DEVICE_ID_VERDE) ||
                (adapter->pdev->vendor == PCI_VENDOR_ID_LSI_LOGIC &&
                adapter->pdev->device == PCI_DEVICE_ID_DOBSON) ||
                (adapter->pdev->vendor == PCI_VENDOR_ID_LSI_LOGIC &&
                adapter->pdev->device == PCI_DEVICE_ID_LINDSAY) ||
                (adapter->pdev->vendor == PCI_VENDOR_ID_DELL &&
                adapter->pdev->device == PCI_DEVICE_ID_PERC4_DI_EVERGLADES) ||
                (adapter->pdev->vendor == PCI_VENDOR_ID_DELL &&
                adapter->pdev->device == PCI_DEVICE_ID_PERC4E_DI_KOBUK)) {
                if (dma_set_mask(&adapter->pdev->dev, DMA_BIT_MASK(64))) {
                        con_log(CL_ANN, (KERN_WARNING
                                "megaraid: DMA mask for 64-bit failed\n"));

                        if (dma_set_mask(&adapter->pdev->dev,
                                                DMA_BIT_MASK(32))) {
                                con_log(CL_ANN, (KERN_WARNING
                                        "megaraid: 32-bit DMA mask failed\n"));
                                goto out_free_sysfs_res;
                        }
                }
        }

        // setup tasklet for DPC
        tasklet_init(&adapter->dpc_h, megaraid_mbox_dpc,
                        (unsigned long)adapter);

        con_log(CL_DLEVEL1, (KERN_INFO
                "megaraid mbox hba successfully initialized\n"));

        return 0;

out_free_sysfs_res:
        megaraid_sysfs_free_resources(adapter);
out_free_irq:
        free_irq(adapter->irq, adapter);
out_alloc_cmds:
        megaraid_free_cmd_packets(adapter);
out_iounmap:
        iounmap(raid_dev->baseaddr);
out_release_regions:
        pci_release_regions(pdev);
out_free_raid_dev:
        kfree(raid_dev);

        return -1;
}


/**
 * megaraid_fini_mbox - undo controller initialization
 * @adapter             : our soft state
 */
static void
megaraid_fini_mbox(adapter_t *adapter)
{
        mraid_device_t *raid_dev = ADAP2RAIDDEV(adapter);

        // flush all caches
        megaraid_mbox_flush_cache(adapter);

        tasklet_kill(&adapter->dpc_h);

        megaraid_sysfs_free_resources(adapter);

        megaraid_free_cmd_packets(adapter);

        free_irq(adapter->irq, adapter);

        iounmap(raid_dev->baseaddr);

        pci_release_regions(adapter->pdev);

        kfree(raid_dev);

        return;
}


/**
 * megaraid_alloc_cmd_packets - allocate shared mailbox
 * @adapter             : soft state of the raid controller
 *
 * Allocate and align the shared mailbox. This mailbox is used to issue
 * all the commands. For IO based controllers, the mailbox is also registered
 * with the FW. Allocate memory for all commands as well.
 * This is our big allocator.
 */
static int
megaraid_alloc_cmd_packets(adapter_t *adapter)
{
        mraid_device_t          *raid_dev = ADAP2RAIDDEV(adapter);
        struct pci_dev          *pdev;
        unsigned long           align;
        scb_t                   *scb;
        mbox_ccb_t              *ccb;
        struct mraid_pci_blk    *epthru_pci_blk;
        struct mraid_pci_blk    *sg_pci_blk;
        struct mraid_pci_blk    *mbox_pci_blk;
        int                     i;

        pdev = adapter->pdev;

        /*
         * Setup the mailbox
         * Allocate the common 16-byte aligned memory for the handshake
         * mailbox.
         */
        raid_dev->una_mbox64 = dma_alloc_coherent(&adapter->pdev->dev,
                                                  sizeof(mbox64_t),
                                                  &raid_dev->una_mbox64_dma,
                                                  GFP_KERNEL);

        if (!raid_dev->una_mbox64) {
                con_log(CL_ANN, (KERN_WARNING
                        "megaraid: out of memory, %s %d\n", __func__,
                        __LINE__));
                return -1;
        }

        /*
         * Align the mailbox at 16-byte boundary
         */
        raid_dev->mbox  = &raid_dev->una_mbox64->mbox32;

        raid_dev->mbox  = (mbox_t *)((((unsigned long)raid_dev->mbox) + 15) &
                                (~0UL ^ 0xFUL));

        raid_dev->mbox64 = (mbox64_t *)(((unsigned long)raid_dev->mbox) - 8);

        align = ((void *)raid_dev->mbox -
                        ((void *)&raid_dev->una_mbox64->mbox32));

        raid_dev->mbox_dma = (unsigned long)raid_dev->una_mbox64_dma + 8 +
                        align;

        // Allocate memory for commands issued internally
        adapter->ibuf = dma_alloc_coherent(&pdev->dev, MBOX_IBUF_SIZE,
                                           &adapter->ibuf_dma_h, GFP_KERNEL);
        if (!adapter->ibuf) {

                con_log(CL_ANN, (KERN_WARNING
                        "megaraid: out of memory, %s %d\n", __func__,
                        __LINE__));

                goto out_free_common_mbox;
        }

        // Allocate memory for our SCSI Command Blocks and their associated
        // memory

        /*
         * Allocate memory for the base list of scb. Later allocate memory for
         * CCBs and embedded components of each CCB and point the pointers in
         * scb to the allocated components
         * NOTE: The code to allocate SCB will be duplicated in all the LLD
         * since the calling routine does not yet know the number of available
         * commands.
         */
        adapter->kscb_list = kcalloc(MBOX_MAX_SCSI_CMDS, sizeof(scb_t), GFP_KERNEL);

        if (adapter->kscb_list == NULL) {
                con_log(CL_ANN, (KERN_WARNING
                        "megaraid: out of memory, %s %d\n", __func__,
                        __LINE__));
                goto out_free_ibuf;
        }

        // memory allocation for our command packets
        if (megaraid_mbox_setup_dma_pools(adapter) != 0) {
                con_log(CL_ANN, (KERN_WARNING
                        "megaraid: out of memory, %s %d\n", __func__,
                        __LINE__));
                goto out_free_scb_list;
        }

        // Adjust the scb pointers and link in the free pool
        epthru_pci_blk  = raid_dev->epthru_pool;
        sg_pci_blk      = raid_dev->sg_pool;
        mbox_pci_blk    = raid_dev->mbox_pool;

        for (i = 0; i < MBOX_MAX_SCSI_CMDS; i++) {
                scb                     = adapter->kscb_list + i;
                ccb                     = raid_dev->ccb_list + i;

                ccb->mbox       = (mbox_t *)(mbox_pci_blk[i].vaddr + 16);
                ccb->raw_mbox   = (uint8_t *)ccb->mbox;
                ccb->mbox64     = (mbox64_t *)(mbox_pci_blk[i].vaddr + 8);
                ccb->mbox_dma_h = (unsigned long)mbox_pci_blk[i].dma_addr + 16;

                // make sure the mailbox is aligned properly
                if (ccb->mbox_dma_h & 0x0F) {
                        con_log(CL_ANN, (KERN_CRIT
                                "megaraid mbox: not aligned on 16-bytes\n"));

                        goto out_teardown_dma_pools;
                }

                ccb->epthru             = (mraid_epassthru_t *)
                                                epthru_pci_blk[i].vaddr;
                ccb->epthru_dma_h       = epthru_pci_blk[i].dma_addr;
                ccb->pthru              = (mraid_passthru_t *)ccb->epthru;
                ccb->pthru_dma_h        = ccb->epthru_dma_h;


                ccb->sgl64              = (mbox_sgl64 *)sg_pci_blk[i].vaddr;
                ccb->sgl_dma_h          = sg_pci_blk[i].dma_addr;
                ccb->sgl32              = (mbox_sgl32 *)ccb->sgl64;

                scb->ccb                = (caddr_t)ccb;
                scb->gp                 = 0;

                scb->sno                = i;    // command index

                scb->scp                = NULL;
                scb->state              = SCB_FREE;
                scb->dma_direction      = DMA_NONE;
                scb->dma_type           = MRAID_DMA_NONE;
                scb->dev_channel        = -1;
                scb->dev_target         = -1;

                // put scb in the free pool
                list_add_tail(&scb->list, &adapter->kscb_pool);
        }

        return 0;

out_teardown_dma_pools:
        megaraid_mbox_teardown_dma_pools(adapter);
out_free_scb_list:
        kfree(adapter->kscb_list);
out_free_ibuf:
        dma_free_coherent(&pdev->dev, MBOX_IBUF_SIZE, (void *)adapter->ibuf,
                adapter->ibuf_dma_h);
out_free_common_mbox:
        dma_free_coherent(&adapter->pdev->dev, sizeof(mbox64_t),
                (caddr_t)raid_dev->una_mbox64, raid_dev->una_mbox64_dma);

        return -1;
}


/**
 * megaraid_free_cmd_packets - free memory
 * @adapter             : soft state of the raid controller
 *
 * Release memory resources allocated for commands.
 */
static void
megaraid_free_cmd_packets(adapter_t *adapter)
{
        mraid_device_t *raid_dev = ADAP2RAIDDEV(adapter);

        megaraid_mbox_teardown_dma_pools(adapter);

        kfree(adapter->kscb_list);

        dma_free_coherent(&adapter->pdev->dev, MBOX_IBUF_SIZE,
                (void *)adapter->ibuf, adapter->ibuf_dma_h);

        dma_free_coherent(&adapter->pdev->dev, sizeof(mbox64_t),
                (caddr_t)raid_dev->una_mbox64, raid_dev->una_mbox64_dma);
        return;
}


/**
 * megaraid_mbox_setup_dma_pools - setup dma pool for command packets
 * @adapter             : HBA soft state
 *
 * Setup the dma pools for mailbox, passthru and extended passthru structures,
 * and scatter-gather lists.
 */
static int
megaraid_mbox_setup_dma_pools(adapter_t *adapter)
{
        mraid_device_t          *raid_dev = ADAP2RAIDDEV(adapter);
        struct mraid_pci_blk    *epthru_pci_blk;
        struct mraid_pci_blk    *sg_pci_blk;
        struct mraid_pci_blk    *mbox_pci_blk;
        int                     i;



        // Allocate memory for 16-bytes aligned mailboxes
        raid_dev->mbox_pool_handle = dma_pool_create("megaraid mbox pool",
                                                &adapter->pdev->dev,
                                                sizeof(mbox64_t) + 16,
                                                16, 0);

        if (raid_dev->mbox_pool_handle == NULL) {
                goto fail_setup_dma_pool;
        }

        mbox_pci_blk = raid_dev->mbox_pool;
        for (i = 0; i < MBOX_MAX_SCSI_CMDS; i++) {
                mbox_pci_blk[i].vaddr = dma_pool_alloc(
                                                raid_dev->mbox_pool_handle,
                                                GFP_KERNEL,
                                                &mbox_pci_blk[i].dma_addr);
                if (!mbox_pci_blk[i].vaddr) {
                        goto fail_setup_dma_pool;
                }
        }

        /*
         * Allocate memory for each embedded passthru strucuture pointer
         * Request for a 128 bytes aligned structure for each passthru command
         * structure
         * Since passthru and extended passthru commands are exclusive, they
         * share common memory pool. Passthru structures piggyback on memory
         * allocated to extended passthru since passthru is smaller of the two
         */
        raid_dev->epthru_pool_handle = dma_pool_create("megaraid mbox pthru",
                        &adapter->pdev->dev, sizeof(mraid_epassthru_t), 128, 0);

        if (raid_dev->epthru_pool_handle == NULL) {
                goto fail_setup_dma_pool;
        }

        epthru_pci_blk = raid_dev->epthru_pool;
        for (i = 0; i < MBOX_MAX_SCSI_CMDS; i++) {
                epthru_pci_blk[i].vaddr = dma_pool_alloc(
                                                raid_dev->epthru_pool_handle,
                                                GFP_KERNEL,
                                                &epthru_pci_blk[i].dma_addr);
                if (!epthru_pci_blk[i].vaddr) {
                        goto fail_setup_dma_pool;
                }
        }


        // Allocate memory for each scatter-gather list. Request for 512 bytes
        // alignment for each sg list
        raid_dev->sg_pool_handle = dma_pool_create("megaraid mbox sg",
                                        &adapter->pdev->dev,
                                        sizeof(mbox_sgl64) * MBOX_MAX_SG_SIZE,
                                        512, 0);

        if (raid_dev->sg_pool_handle == NULL) {
                goto fail_setup_dma_pool;
        }

        sg_pci_blk = raid_dev->sg_pool;
        for (i = 0; i < MBOX_MAX_SCSI_CMDS; i++) {
                sg_pci_blk[i].vaddr = dma_pool_alloc(
                                                raid_dev->sg_pool_handle,
                                                GFP_KERNEL,
                                                &sg_pci_blk[i].dma_addr);
                if (!sg_pci_blk[i].vaddr) {
                        goto fail_setup_dma_pool;
                }
        }

        return 0;

fail_setup_dma_pool:
        megaraid_mbox_teardown_dma_pools(adapter);
        return -1;
}


/**
 * megaraid_mbox_teardown_dma_pools - teardown dma pools for command packets
 * @adapter             : HBA soft state
 *
 * Teardown the dma pool for mailbox, passthru and extended passthru
 * structures, and scatter-gather lists.
 */
static void
megaraid_mbox_teardown_dma_pools(adapter_t *adapter)
{
        mraid_device_t          *raid_dev = ADAP2RAIDDEV(adapter);
        struct mraid_pci_blk    *epthru_pci_blk;
        struct mraid_pci_blk    *sg_pci_blk;
        struct mraid_pci_blk    *mbox_pci_blk;
        int                     i;


        sg_pci_blk = raid_dev->sg_pool;
        for (i = 0; i < MBOX_MAX_SCSI_CMDS && sg_pci_blk[i].vaddr; i++) {
                dma_pool_free(raid_dev->sg_pool_handle, sg_pci_blk[i].vaddr,
                        sg_pci_blk[i].dma_addr);
        }
        dma_pool_destroy(raid_dev->sg_pool_handle);


        epthru_pci_blk = raid_dev->epthru_pool;
        for (i = 0; i < MBOX_MAX_SCSI_CMDS && epthru_pci_blk[i].vaddr; i++) {
                dma_pool_free(raid_dev->epthru_pool_handle,
                        epthru_pci_blk[i].vaddr, epthru_pci_blk[i].dma_addr);
        }
        dma_pool_destroy(raid_dev->epthru_pool_handle);


        mbox_pci_blk = raid_dev->mbox_pool;
        for (i = 0; i < MBOX_MAX_SCSI_CMDS && mbox_pci_blk[i].vaddr; i++) {
                dma_pool_free(raid_dev->mbox_pool_handle,
                        mbox_pci_blk[i].vaddr, mbox_pci_blk[i].dma_addr);
        }
        dma_pool_destroy(raid_dev->mbox_pool_handle);

        return;
}


/**
 * megaraid_alloc_scb - detach and return a scb from the free list
 * @adapter     : controller's soft state
 * @scp         : pointer to the scsi command to be executed
 *
 * Return the scb from the head of the free list. %NULL if there are none
 * available.
 */
static scb_t *
megaraid_alloc_scb(adapter_t *adapter, struct scsi_cmnd *scp)
{
        struct list_head        *head = &adapter->kscb_pool;
        scb_t                   *scb = NULL;
        unsigned long           flags;

        // detach scb from free pool
        spin_lock_irqsave(SCSI_FREE_LIST_LOCK(adapter), flags);

        if (list_empty(head)) {
                spin_unlock_irqrestore(SCSI_FREE_LIST_LOCK(adapter), flags);
                return NULL;
        }

        scb = list_entry(head->next, scb_t, list);
        list_del_init(&scb->list);

        spin_unlock_irqrestore(SCSI_FREE_LIST_LOCK(adapter), flags);

        scb->state      = SCB_ACTIVE;
        scb->scp        = scp;
        scb->dma_type   = MRAID_DMA_NONE;

        return scb;
}


/**
 * megaraid_dealloc_scb - return the scb to the free pool
 * @adapter     : controller's soft state
 * @scb         : scb to be freed
 *
 * Return the scb back to the free list of scbs. The caller must 'flush' the
 * SCB before calling us. E.g., performing pci_unamp and/or pci_sync etc.
 * NOTE NOTE: Make sure the scb is not on any list before calling this
 * routine.
 */
static inline void
megaraid_dealloc_scb(adapter_t *adapter, scb_t *scb)
{
        unsigned long           flags;

        // put scb in the free pool
        scb->state      = SCB_FREE;
        scb->scp        = NULL;
        spin_lock_irqsave(SCSI_FREE_LIST_LOCK(adapter), flags);

        list_add(&scb->list, &adapter->kscb_pool);

        spin_unlock_irqrestore(SCSI_FREE_LIST_LOCK(adapter), flags);

        return;
}


/**
 * megaraid_mbox_mksgl - make the scatter-gather list
 * @adapter     : controller's soft state
 * @scb         : scsi control block
 *
 * Prepare the scatter-gather list.
 */
static int
megaraid_mbox_mksgl(adapter_t *adapter, scb_t *scb)
{
        struct scatterlist      *sgl;
        mbox_ccb_t              *ccb;
        struct scsi_cmnd        *scp;
        int                     sgcnt;
        int                     i;


        scp     = scb->scp;
        ccb     = (mbox_ccb_t *)scb->ccb;

        sgcnt = scsi_dma_map(scp);
        BUG_ON(sgcnt < 0 || sgcnt > adapter->sglen);

        // no mapping required if no data to be transferred
        if (!sgcnt)
                return 0;

        scb->dma_type = MRAID_DMA_WSG;

        scsi_for_each_sg(scp, sgl, sgcnt, i) {
                ccb->sgl64[i].address   = sg_dma_address(sgl);
                ccb->sgl64[i].length    = sg_dma_len(sgl);
        }

        // Return count of SG nodes
        return sgcnt;
}


/**
 * mbox_post_cmd - issue a mailbox command
 * @adapter     : controller's soft state
 * @scb         : command to be issued
 *
 * Post the command to the controller if mailbox is available.
 */
static int
mbox_post_cmd(adapter_t *adapter, scb_t *scb)
{
        mraid_device_t  *raid_dev = ADAP2RAIDDEV(adapter);
        mbox64_t        *mbox64;
        mbox_t          *mbox;
        mbox_ccb_t      *ccb;
        unsigned long   flags;
        unsigned int    i = 0;


        ccb     = (mbox_ccb_t *)scb->ccb;
        mbox    = raid_dev->mbox;
        mbox64  = raid_dev->mbox64;

        /*
         * Check for busy mailbox. If it is, return failure - the caller
         * should retry later.
         */
        spin_lock_irqsave(MAILBOX_LOCK(raid_dev), flags);

        if (unlikely(mbox->busy)) {
                do {
                        udelay(1);
                        i++;
                        rmb();
                } while(mbox->busy && (i < max_mbox_busy_wait));

                if (mbox->busy) {

                        spin_unlock_irqrestore(MAILBOX_LOCK(raid_dev), flags);

                        return -1;
                }
        }


        // Copy this command's mailbox data into "adapter's" mailbox
        memcpy((caddr_t)mbox64, (caddr_t)ccb->mbox64, 22);
        mbox->cmdid = scb->sno;

        adapter->outstanding_cmds++;

        mbox->busy      = 1;    // Set busy
        mbox->poll      = 0;
        mbox->ack       = 0;
        wmb();

        WRINDOOR(raid_dev, raid_dev->mbox_dma | 0x1);

        spin_unlock_irqrestore(MAILBOX_LOCK(raid_dev), flags);

        return 0;
}


/**
 * megaraid_queue_command_lck - generic queue entry point for all LLDs
 * @scp         : pointer to the scsi command to be executed
 * @done        : callback routine to be called after the cmd has be completed
 *
 * Queue entry point for mailbox based controllers.
 */
static int
megaraid_queue_command_lck(struct scsi_cmnd *scp, void (*done)(struct scsi_cmnd *))
{
        adapter_t       *adapter;
        scb_t           *scb;
        int             if_busy;

        adapter         = SCP2ADAPTER(scp);
        scp->scsi_done  = done;
        scp->result     = 0;

        /*
         * Allocate and build a SCB request
         * if_busy flag will be set if megaraid_mbox_build_cmd() command could
         * not allocate scb. We will return non-zero status in that case.
         * NOTE: scb can be null even though certain commands completed
         * successfully, e.g., MODE_SENSE and TEST_UNIT_READY, it would
         * return 0 in that case, and we would do the callback right away.
         */
        if_busy = 0;
        scb = megaraid_mbox_build_cmd(adapter, scp, &if_busy);
        if (!scb) {     // command already completed
                done(scp);
                return 0;
        }

        megaraid_mbox_runpendq(adapter, scb);
        return if_busy;
}

static DEF_SCSI_QCMD(megaraid_queue_command)

/**
 * megaraid_mbox_build_cmd - transform the mid-layer scsi commands
 * @adapter     : controller's soft state
 * @scp         : mid-layer scsi command pointer
 * @busy        : set if request could not be completed because of lack of
 *              resources
 *
 * Transform the mid-layer scsi command to megaraid firmware lingua.
 * Convert the command issued by mid-layer to format understood by megaraid
 * firmware. We also complete certain commands without sending them to firmware.
 */
static scb_t *
megaraid_mbox_build_cmd(adapter_t *adapter, struct scsi_cmnd *scp, int *busy)
{
        mraid_device_t          *rdev = ADAP2RAIDDEV(adapter);
        int                     channel;
        int                     target;
        int                     islogical;
        mbox_ccb_t              *ccb;
        mraid_passthru_t        *pthru;
        mbox64_t                *mbox64;
        mbox_t                  *mbox;
        scb_t                   *scb;
        char                    skip[] = "skipping";
        char                    scan[] = "scanning";
        char                    *ss;


        /*
         * Get the appropriate device map for the device this command is
         * intended for
         */
        MRAID_GET_DEVICE_MAP(adapter, scp, channel, target, islogical);

        /*
         * Logical drive commands
         */
        if (islogical) {
                switch (scp->cmnd[0]) {
                case TEST_UNIT_READY:
                        /*
                         * Do we support clustering and is the support enabled
                         * If no, return success always
                         */
                        if (!adapter->ha) {
                                scp->result = (DID_OK << 16);
                                return NULL;
                        }

                        if (!(scb = megaraid_alloc_scb(adapter, scp))) {
                                scp->result = (DID_ERROR << 16);
                                *busy = 1;
                                return NULL;
                        }

                        scb->dma_direction      = scp->sc_data_direction;
                        scb->dev_channel        = 0xFF;
                        scb->dev_target         = target;
                        ccb                     = (mbox_ccb_t *)scb->ccb;

                        /*
                         * The command id will be provided by the command
                         * issuance routine
                         */
                        ccb->raw_mbox[0]        = CLUSTER_CMD;
                        ccb->raw_mbox[2]        = RESERVATION_STATUS;
                        ccb->raw_mbox[3]        = target;

                        return scb;

                case MODE_SENSE:
                {
                        struct scatterlist      *sgl;
                        caddr_t                 vaddr;

                        sgl = scsi_sglist(scp);
                        if (sg_page(sgl)) {
                                vaddr = (caddr_t) sg_virt(&sgl[0]);

                                memset(vaddr, 0, scp->cmnd[4]);
                        }
                        else {
                                con_log(CL_ANN, (KERN_WARNING
                                                 "megaraid mailbox: invalid sg:%d\n",
                                                 __LINE__));
                        }
                }
                scp->result = (DID_OK << 16);
                return NULL;

                case INQUIRY:
                        /*
                         * Display the channel scan for logical drives
                         * Do not display scan for a channel if already done.
                         */
                        if (!(rdev->last_disp & (1L << SCP2CHANNEL(scp)))) {

                                con_log(CL_ANN, (KERN_INFO
                                        "scsi[%d]: scanning scsi channel %d",
                                        adapter->host->host_no,
                                        SCP2CHANNEL(scp)));

                                con_log(CL_ANN, (
                                        " [virtual] for logical drives\n"));

                                rdev->last_disp |= (1L << SCP2CHANNEL(scp));
                        }

                        if (scp->cmnd[1] & MEGA_SCSI_INQ_EVPD) {
                                scsi_build_sense(scp, 0, ILLEGAL_REQUEST,
                                                 MEGA_INVALID_FIELD_IN_CDB, 0);
                                return NULL;
                        }

                        fallthrough;

                case READ_CAPACITY:
                        /*
                         * Do not allow LUN > 0 for logical drives and
                         * requests for more than 40 logical drives
                         */
                        if (SCP2LUN(scp)) {
                                scp->result = (DID_BAD_TARGET << 16);
                                return NULL;
                        }
                        if ((target % 0x80) >= MAX_LOGICAL_DRIVES_40LD) {
                                scp->result = (DID_BAD_TARGET << 16);
                                return NULL;
                        }


                        /* Allocate a SCB and initialize passthru */
                        if (!(scb = megaraid_alloc_scb(adapter, scp))) {
                                scp->result = (DID_ERROR << 16);
                                *busy = 1;
                                return NULL;
                        }

                        ccb                     = (mbox_ccb_t *)scb->ccb;
                        scb->dev_channel        = 0xFF;
                        scb->dev_target         = target;
                        pthru                   = ccb->pthru;
                        mbox                    = ccb->mbox;
                        mbox64                  = ccb->mbox64;

                        pthru->timeout          = 0;
                        pthru->ars              = 1;
                        pthru->reqsenselen      = 14;
                        pthru->islogical        = 1;
                        pthru->logdrv           = target;
                        pthru->cdblen           = scp->cmd_len;
                        memcpy(pthru->cdb, scp->cmnd, scp->cmd_len);

                        mbox->cmd               = MBOXCMD_PASSTHRU64;
                        scb->dma_direction      = scp->sc_data_direction;

                        pthru->dataxferlen      = scsi_bufflen(scp);
                        pthru->dataxferaddr     = ccb->sgl_dma_h;
                        pthru->numsge           = megaraid_mbox_mksgl(adapter,
                                                        scb);

                        mbox->xferaddr          = 0xFFFFFFFF;
                        mbox64->xferaddr_lo     = (uint32_t )ccb->pthru_dma_h;
                        mbox64->xferaddr_hi     = 0;

                        return scb;

                case READ_6:
                case WRITE_6:
                case READ_10:
                case WRITE_10:
                case READ_12:
                case WRITE_12:

                        /*
                         * Allocate a SCB and initialize mailbox
                         */
                        if (!(scb = megaraid_alloc_scb(adapter, scp))) {
                                scp->result = (DID_ERROR << 16);
                                *busy = 1;
                                return NULL;
                        }
                        ccb                     = (mbox_ccb_t *)scb->ccb;
                        scb->dev_channel        = 0xFF;
                        scb->dev_target         = target;
                        mbox                    = ccb->mbox;
                        mbox64                  = ccb->mbox64;
                        mbox->logdrv            = target;

                        /*
                         * A little HACK: 2nd bit is zero for all scsi read
                         * commands and is set for all scsi write commands
                         */
                        mbox->cmd = (scp->cmnd[0] & 0x02) ?  MBOXCMD_LWRITE64:
                                        MBOXCMD_LREAD64 ;

                        /*
                         * 6-byte READ(0x08) or WRITE(0x0A) cdb
                         */
                        if (scp->cmd_len == 6) {
                                mbox->numsectors = (uint32_t)scp->cmnd[4];
                                mbox->lba =
                                        ((uint32_t)scp->cmnd[1] << 16)  |
                                        ((uint32_t)scp->cmnd[2] << 8)   |
                                        (uint32_t)scp->cmnd[3];

                                mbox->lba &= 0x1FFFFF;
                        }

                        /*
                         * 10-byte READ(0x28) or WRITE(0x2A) cdb
                         */
                        else if (scp->cmd_len == 10) {
                                mbox->numsectors =
                                        (uint32_t)scp->cmnd[8] |
                                        ((uint32_t)scp->cmnd[7] << 8);
                                mbox->lba =
                                        ((uint32_t)scp->cmnd[2] << 24) |
                                        ((uint32_t)scp->cmnd[3] << 16) |
                                        ((uint32_t)scp->cmnd[4] << 8) |
                                        (uint32_t)scp->cmnd[5];
                        }

                        /*
                         * 12-byte READ(0xA8) or WRITE(0xAA) cdb
                         */
                        else if (scp->cmd_len == 12) {
                                mbox->lba =
                                        ((uint32_t)scp->cmnd[2] << 24) |
                                        ((uint32_t)scp->cmnd[3] << 16) |
                                        ((uint32_t)scp->cmnd[4] << 8) |
                                        (uint32_t)scp->cmnd[5];

                                mbox->numsectors =
                                        ((uint32_t)scp->cmnd[6] << 24) |
                                        ((uint32_t)scp->cmnd[7] << 16) |
                                        ((uint32_t)scp->cmnd[8] << 8) |
                                        (uint32_t)scp->cmnd[9];
                        }
                        else {
                                con_log(CL_ANN, (KERN_WARNING
                                        "megaraid: unsupported CDB length\n"));

                                megaraid_dealloc_scb(adapter, scb);

                                scp->result = (DID_ERROR << 16);
                                return NULL;
                        }

                        scb->dma_direction = scp->sc_data_direction;

                        // Calculate Scatter-Gather info
                        mbox64->xferaddr_lo     = (uint32_t )ccb->sgl_dma_h;
                        mbox->numsge            = megaraid_mbox_mksgl(adapter,
                                                        scb);
                        mbox->xferaddr          = 0xFFFFFFFF;
                        mbox64->xferaddr_hi     = 0;

                        return scb;

                case RESERVE:
                case RELEASE:
                        /*
                         * Do we support clustering and is the support enabled
                         */
                        if (!adapter->ha) {
                                scp->result = (DID_BAD_TARGET << 16);
                                return NULL;
                        }

                        /*
                         * Allocate a SCB and initialize mailbox
                         */
                        if (!(scb = megaraid_alloc_scb(adapter, scp))) {
                                scp->result = (DID_ERROR << 16);
                                *busy = 1;
                                return NULL;
                        }

                        ccb                     = (mbox_ccb_t *)scb->ccb;
                        scb->dev_channel        = 0xFF;
                        scb->dev_target         = target;
                        ccb->raw_mbox[0]        = CLUSTER_CMD;
                        ccb->raw_mbox[2]        =  (scp->cmnd[0] == RESERVE) ?
                                                RESERVE_LD : RELEASE_LD;

                        ccb->raw_mbox[3]        = target;
                        scb->dma_direction      = scp->sc_data_direction;

                        return scb;

                default:
                        scp->result = (DID_BAD_TARGET << 16);
                        return NULL;
                }
        }
        else { // Passthru device commands

                // Do not allow access to target id > 15 or LUN > 7
                if (target > 15 || SCP2LUN(scp) > 7) {
                        scp->result = (DID_BAD_TARGET << 16);
                        return NULL;
                }

                // if fast load option was set and scan for last device is
                // over, reset the fast_load flag so that during a possible
                // next scan, devices can be made available
                if (rdev->fast_load && (target == 15) &&
                        (SCP2CHANNEL(scp) == adapter->max_channel -1)) {

                        con_log(CL_ANN, (KERN_INFO
                        "megaraid[%d]: physical device scan re-enabled\n",
                                adapter->host->host_no));
                        rdev->fast_load = 0;
                }

                /*
                 * Display the channel scan for physical devices
                 */
                if (!(rdev->last_disp & (1L << SCP2CHANNEL(scp)))) {

                        ss = rdev->fast_load ? skip : scan;

                        con_log(CL_ANN, (KERN_INFO
                                "scsi[%d]: %s scsi channel %d [Phy %d]",
                                adapter->host->host_no, ss, SCP2CHANNEL(scp),
                                channel));

                        con_log(CL_ANN, (
                                " for non-raid devices\n"));

                        rdev->last_disp |= (1L << SCP2CHANNEL(scp));
                }

                // disable channel sweep if fast load option given
                if (rdev->fast_load) {
                        scp->result = (DID_BAD_TARGET << 16);
                        return NULL;
                }

                // Allocate a SCB and initialize passthru
                if (!(scb = megaraid_alloc_scb(adapter, scp))) {
                        scp->result = (DID_ERROR << 16);
                        *busy = 1;
                        return NULL;
                }

                ccb                     = (mbox_ccb_t *)scb->ccb;
                scb->dev_channel        = channel;
                scb->dev_target         = target;
                scb->dma_direction      = scp->sc_data_direction;
                mbox                    = ccb->mbox;
                mbox64                  = ccb->mbox64;

                // Does this firmware support extended CDBs
                if (adapter->max_cdb_sz == 16) {
                        mbox->cmd               = MBOXCMD_EXTPTHRU;

                        megaraid_mbox_prepare_epthru(adapter, scb, scp);

                        mbox64->xferaddr_lo     = (uint32_t)ccb->epthru_dma_h;
                        mbox64->xferaddr_hi     = 0;
                        mbox->xferaddr          = 0xFFFFFFFF;
                }
                else {
                        mbox->cmd = MBOXCMD_PASSTHRU64;

                        megaraid_mbox_prepare_pthru(adapter, scb, scp);

                        mbox64->xferaddr_lo     = (uint32_t)ccb->pthru_dma_h;
                        mbox64->xferaddr_hi     = 0;
                        mbox->xferaddr          = 0xFFFFFFFF;
                }
                return scb;
        }

        // NOT REACHED
}


/**
 * megaraid_mbox_runpendq - execute commands queued in the pending queue
 * @adapter     : controller's soft state
 * @scb_q       : SCB to be queued in the pending list
 *
 * Scan the pending list for commands which are not yet issued and try to
 * post to the controller. The SCB can be a null pointer, which would indicate
 * no SCB to be queue, just try to execute the ones in the pending list.
 *
 * NOTE: We do not actually traverse the pending list. The SCBs are plucked
 * out from the head of the pending list. If it is successfully issued, the
 * next SCB is at the head now.
 */
static void
megaraid_mbox_runpendq(adapter_t *adapter, scb_t *scb_q)
{
        scb_t                   *scb;
        unsigned long           flags;

        spin_lock_irqsave(PENDING_LIST_LOCK(adapter), flags);

        if (scb_q) {
                scb_q->state = SCB_PENDQ;
                list_add_tail(&scb_q->list, &adapter->pend_list);
        }

        // if the adapter in not in quiescent mode, post the commands to FW
        if (adapter->quiescent) {
                spin_unlock_irqrestore(PENDING_LIST_LOCK(adapter), flags);
                return;
        }

        while (!list_empty(&adapter->pend_list)) {

                assert_spin_locked(PENDING_LIST_LOCK(adapter));

                scb = list_entry(adapter->pend_list.next, scb_t, list);

                // remove the scb from the pending list and try to
                // issue. If we are unable to issue it, put back in
                // the pending list and return

                list_del_init(&scb->list);

                spin_unlock_irqrestore(PENDING_LIST_LOCK(adapter), flags);

                // if mailbox was busy, return SCB back to pending
                // list. Make sure to add at the head, since that's
                // where it would have been removed from

                scb->state = SCB_ISSUED;

                if (mbox_post_cmd(adapter, scb) != 0) {

                        spin_lock_irqsave(PENDING_LIST_LOCK(adapter), flags);

                        scb->state = SCB_PENDQ;

                        list_add(&scb->list, &adapter->pend_list);

                        spin_unlock_irqrestore(PENDING_LIST_LOCK(adapter),
                                flags);

                        return;
                }

                spin_lock_irqsave(PENDING_LIST_LOCK(adapter), flags);
        }

        spin_unlock_irqrestore(PENDING_LIST_LOCK(adapter), flags);


        return;
}


/**
 * megaraid_mbox_prepare_pthru - prepare a command for physical devices
 * @adapter     : pointer to controller's soft state
 * @scb         : scsi control block
 * @scp         : scsi command from the mid-layer
 *
 * Prepare a command for the scsi physical devices.
 */
static void
megaraid_mbox_prepare_pthru(adapter_t *adapter, scb_t *scb,
                struct scsi_cmnd *scp)
{
        mbox_ccb_t              *ccb;
        mraid_passthru_t        *pthru;
        uint8_t                 channel;
        uint8_t                 target;

        ccb     = (mbox_ccb_t *)scb->ccb;
        pthru   = ccb->pthru;
        channel = scb->dev_channel;
        target  = scb->dev_target;

        // 0=6sec, 1=60sec, 2=10min, 3=3hrs, 4=NO timeout
        pthru->timeout          = 4;    
        pthru->ars              = 1;
        pthru->islogical        = 0;
        pthru->channel          = 0;
        pthru->target           = (channel << 4) | target;
        pthru->logdrv           = SCP2LUN(scp);
        pthru->reqsenselen      = 14;
        pthru->cdblen           = scp->cmd_len;

        memcpy(pthru->cdb, scp->cmnd, scp->cmd_len);

        if (scsi_bufflen(scp)) {
                pthru->dataxferlen      = scsi_bufflen(scp);
                pthru->dataxferaddr     = ccb->sgl_dma_h;
                pthru->numsge           = megaraid_mbox_mksgl(adapter, scb);
        }
        else {
                pthru->dataxferaddr     = 0;
                pthru->dataxferlen      = 0;
                pthru->numsge           = 0;
        }
        return;
}


/**
 * megaraid_mbox_prepare_epthru - prepare a command for physical devices
 * @adapter     : pointer to controller's soft state
 * @scb         : scsi control block
 * @scp         : scsi command from the mid-layer
 *
 * Prepare a command for the scsi physical devices. This routine prepares
 * commands for devices which can take extended CDBs (>10 bytes).
 */
static void
megaraid_mbox_prepare_epthru(adapter_t *adapter, scb_t *scb,
                struct scsi_cmnd *scp)
{
        mbox_ccb_t              *ccb;
        mraid_epassthru_t       *epthru;
        uint8_t                 channel;
        uint8_t                 target;

        ccb     = (mbox_ccb_t *)scb->ccb;
        epthru  = ccb->epthru;
        channel = scb->dev_channel;
        target  = scb->dev_target;

        // 0=6sec, 1=60sec, 2=10min, 3=3hrs, 4=NO timeout
        epthru->timeout         = 4;    
        epthru->ars             = 1;
        epthru->islogical       = 0;
        epthru->channel         = 0;
        epthru->target          = (channel << 4) | target;
        epthru->logdrv          = SCP2LUN(scp);