// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright IBM Corp. 2006, 2012
 * Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
 *            Martin Schwidefsky <schwidefsky@de.ibm.com>
 *            Ralph Wuerthner <rwuerthn@de.ibm.com>
 *            Felix Beck <felix.beck@de.ibm.com>
 *            Holger Dengler <hd@linux.vnet.ibm.com>
 *
 * Adjunct processor bus.
 */

#define KMSG_COMPONENT "ap"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/kernel_stat.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/freezer.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/slab.h>
#include <linux/notifier.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <asm/airq.h>
#include <linux/atomic.h>
#include <asm/isc.h>
#include <linux/hrtimer.h>
#include <linux/ktime.h>
#include <asm/facility.h>
#include <linux/crypto.h>
#include <linux/mod_devicetable.h>
#include <linux/debugfs.h>
#include <linux/ctype.h>

#include "ap_bus.h"
#include "ap_debug.h"

/*
 * Module parameters; note though this file itself isn't modular.
 */
int ap_domain_index = -1;       /* Adjunct Processor Domain Index */
static DEFINE_SPINLOCK(ap_domain_lock);
module_param_named(domain, ap_domain_index, int, 0440);
MODULE_PARM_DESC(domain, "domain index for ap devices");
EXPORT_SYMBOL(ap_domain_index);

static int ap_thread_flag;
module_param_named(poll_thread, ap_thread_flag, int, 0440);
MODULE_PARM_DESC(poll_thread, "Turn on/off poll thread, default is 0 (off).");

static char *apm_str;
module_param_named(apmask, apm_str, charp, 0440);
MODULE_PARM_DESC(apmask, "AP bus adapter mask.");

static char *aqm_str;
module_param_named(aqmask, aqm_str, charp, 0440);
MODULE_PARM_DESC(aqmask, "AP bus domain mask.");

static struct device *ap_root_device;

/* Hashtable of all queue devices on the AP bus */
DEFINE_HASHTABLE(ap_queues, 8);
/* lock used for the ap_queues hashtable */
DEFINE_SPINLOCK(ap_queues_lock);

/* Default permissions (ioctl, card and domain masking) */
struct ap_perms ap_perms;
EXPORT_SYMBOL(ap_perms);
DEFINE_MUTEX(ap_perms_mutex);
EXPORT_SYMBOL(ap_perms_mutex);

static struct ap_config_info *ap_configuration;
static bool initialised;

/*
 * AP bus related debug feature things.
 */
debug_info_t *ap_dbf_info;

/*
 * Workqueue timer for bus rescan.
 */
static struct timer_list ap_config_timer;
static int ap_config_time = AP_CONFIG_TIME;
static void ap_scan_bus(struct work_struct *);
static DECLARE_WORK(ap_scan_work, ap_scan_bus);

/*
 * Tasklet & timer for AP request polling and interrupts
 */
static void ap_tasklet_fn(unsigned long);
static DECLARE_TASKLET(ap_tasklet, ap_tasklet_fn, 0);
static DECLARE_WAIT_QUEUE_HEAD(ap_poll_wait);
static struct task_struct *ap_poll_kthread;
static DEFINE_MUTEX(ap_poll_thread_mutex);
static DEFINE_SPINLOCK(ap_poll_timer_lock);
static struct hrtimer ap_poll_timer;
/*
 * In LPAR poll with 4kHz frequency. Poll every 250000 nanoseconds.
 * If z/VM change to 1500000 nanoseconds to adjust to z/VM polling.
 */
static unsigned long long poll_timeout = 250000;

/* Maximum domain id */
static int ap_max_domain_id;

static struct bus_type ap_bus_type;

/* Adapter interrupt definitions */
static void ap_interrupt_handler(struct airq_struct *airq, bool floating);

static int ap_airq_flag;

static struct airq_struct ap_airq = {
        .handler = ap_interrupt_handler,
        .isc = AP_ISC,
};

/**
 * ap_using_interrupts() - Returns non-zero if interrupt support is
 * available.
 */
static inline int ap_using_interrupts(void)
{
        return ap_airq_flag;
}

/**
 * ap_airq_ptr() - Get the address of the adapter interrupt indicator
 *
 * Returns the address of the local-summary-indicator of the adapter
 * interrupt handler for AP, or NULL if adapter interrupts are not
 * available.
 */
void *ap_airq_ptr(void)
{
        if (ap_using_interrupts())
                return ap_airq.lsi_ptr;
        return NULL;
}

/**
 * ap_interrupts_available(): Test if AP interrupts are available.
 *
 * Returns 1 if AP interrupts are available.
 */
static int ap_interrupts_available(void)
{
        return test_facility(65);
}

/**
 * ap_configuration_available(): Test if AP configuration
 * information is available.
 *
 * Returns 1 if AP configuration information is available.
 */
static int ap_configuration_available(void)
{
        return test_facility(12);
}

/**
 * ap_apft_available(): Test if AP facilities test (APFT)
 * facility is available.
 *
 * Returns 1 if APFT is is available.
 */
static int ap_apft_available(void)
{
        return test_facility(15);
}

/*
 * ap_qact_available(): Test if the PQAP(QACT) subfunction is available.
 *
 * Returns 1 if the QACT subfunction is available.
 */
static inline int ap_qact_available(void)
{
        if (ap_configuration)
                return ap_configuration->qact;
        return 0;
}

/*
 * ap_query_configuration(): Fetch cryptographic config info
 *
 * Returns the ap configuration info fetched via PQAP(QCI).
 * On success 0 is returned, on failure a negative errno
 * is returned, e.g. if the PQAP(QCI) instruction is not
 * available, the return value will be -EOPNOTSUPP.
 */
static inline int ap_query_configuration(struct ap_config_info *info)
{
        if (!ap_configuration_available())
                return -EOPNOTSUPP;
        if (!info)
                return -EINVAL;
        return ap_qci(info);
}

/**
 * ap_init_configuration(): Allocate and query configuration array.
 */
static void ap_init_configuration(void)
{
        if (!ap_configuration_available())
                return;

        ap_configuration = kzalloc(sizeof(*ap_configuration), GFP_KERNEL);
        if (!ap_configuration)
                return;
        if (ap_query_configuration(ap_configuration) != 0) {
                kfree(ap_configuration);
                ap_configuration = NULL;
                return;
        }
}

/*
 * ap_test_config(): helper function to extract the nrth bit
 *                   within the unsigned int array field.
 */
static inline int ap_test_config(unsigned int *field, unsigned int nr)
{
        return ap_test_bit((field + (nr >> 5)), (nr & 0x1f));
}

/*
 * ap_test_config_card_id(): Test, whether an AP card ID is configured.
 * @id AP card ID
 *
 * Returns 0 if the card is not configured
 *         1 if the card is configured or
 *           if the configuration information is not available
 */
static inline int ap_test_config_card_id(unsigned int id)
{
        if (!ap_configuration)  /* QCI not supported */
                /* only ids 0...3F may be probed */
                return id < 0x40 ? 1 : 0;
        return ap_test_config(ap_configuration->apm, id);
}

/*
 * ap_test_config_usage_domain(): Test, whether an AP usage domain
 * is configured.
 * @domain AP usage domain ID
 *
 * Returns 0 if the usage domain is not configured
 *         1 if the usage domain is configured or
 *           if the configuration information is not available
 */
int ap_test_config_usage_domain(unsigned int domain)
{
        if (!ap_configuration)  /* QCI not supported */
                return domain < 16;
        return ap_test_config(ap_configuration->aqm, domain);
}
EXPORT_SYMBOL(ap_test_config_usage_domain);

/*
 * ap_test_config_ctrl_domain(): Test, whether an AP control domain
 * is configured.
 * @domain AP control domain ID
 *
 * Returns 1 if the control domain is configured
 *         0 in all other cases
 */
int ap_test_config_ctrl_domain(unsigned int domain)
{
        if (!ap_configuration)  /* QCI not supported */
                return 0;
        return ap_test_config(ap_configuration->adm, domain);
}
EXPORT_SYMBOL(ap_test_config_ctrl_domain);

/**
 * ap_query_queue(): Check if an AP queue is available.
 * @qid: The AP queue number
 * @queue_depth: Pointer to queue depth value
 * @device_type: Pointer to device type value
 * @facilities: Pointer to facility indicator
 */
static int ap_query_queue(ap_qid_t qid, int *queue_depth, int *device_type,
                          unsigned int *facilities)
{
        struct ap_queue_status status;
        unsigned long info;
        int nd;

        if (!ap_test_config_card_id(AP_QID_CARD(qid)))
                return -ENODEV;

        status = ap_test_queue(qid, ap_apft_available(), &info);
        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
                *queue_depth = (int)(info & 0xff);
                *device_type = (int)((info >> 24) & 0xff);
                *facilities = (unsigned int)(info >> 32);
                /* Update maximum domain id */
                nd = (info >> 16) & 0xff;
                /* if N bit is available, z13 and newer */
                if ((info & (1UL << 57)) && nd > 0)
                        ap_max_domain_id = nd;
                else /* older machine types */
                        ap_max_domain_id = 15;
                switch (*device_type) {
                        /* For CEX2 and CEX3 the available functions
                         * are not reflected by the facilities bits.
                         * Instead it is coded into the type. So here
                         * modify the function bits based on the type.
                         */
                case AP_DEVICE_TYPE_CEX2A:
                case AP_DEVICE_TYPE_CEX3A:
                        *facilities |= 0x08000000;
                        break;
                case AP_DEVICE_TYPE_CEX2C:
                case AP_DEVICE_TYPE_CEX3C:
                        *facilities |= 0x10000000;
                        break;
                default:
                        break;
                }
                return 0;
        case AP_RESPONSE_Q_NOT_AVAIL:
        case AP_RESPONSE_DECONFIGURED:
        case AP_RESPONSE_CHECKSTOPPED:
        case AP_RESPONSE_INVALID_ADDRESS:
                return -ENODEV;
        case AP_RESPONSE_RESET_IN_PROGRESS:
        case AP_RESPONSE_OTHERWISE_CHANGED:
        case AP_RESPONSE_BUSY:
                return -EBUSY;
        default:
                BUG();
        }
}

void ap_wait(enum ap_wait wait)
{
        ktime_t hr_time;

        switch (wait) {
        case AP_WAIT_AGAIN:
        case AP_WAIT_INTERRUPT:
                if (ap_using_interrupts())
                        break;
                if (ap_poll_kthread) {
                        wake_up(&ap_poll_wait);
                        break;
                }
                fallthrough;
        case AP_WAIT_TIMEOUT:
                spin_lock_bh(&ap_poll_timer_lock);
                if (!hrtimer_is_queued(&ap_poll_timer)) {
                        hr_time = poll_timeout;
                        hrtimer_forward_now(&ap_poll_timer, hr_time);
                        hrtimer_restart(&ap_poll_timer);
                }
                spin_unlock_bh(&ap_poll_timer_lock);
                break;
        case AP_WAIT_NONE:
        default:
                break;
        }
}

/**
 * ap_request_timeout(): Handling of request timeouts
 * @t: timer making this callback
 *
 * Handles request timeouts.
 */
void ap_request_timeout(struct timer_list *t)
{
        struct ap_queue *aq = from_timer(aq, t, timeout);

        spin_lock_bh(&aq->lock);
        ap_wait(ap_sm_event(aq, AP_EVENT_TIMEOUT));
        spin_unlock_bh(&aq->lock);
}

/**
 * ap_poll_timeout(): AP receive polling for finished AP requests.
 * @unused: Unused pointer.
 *
 * Schedules the AP tasklet using a high resolution timer.
 */
static enum hrtimer_restart ap_poll_timeout(struct hrtimer *unused)
{
        tasklet_schedule(&ap_tasklet);
        return HRTIMER_NORESTART;
}

/**
 * ap_interrupt_handler() - Schedule ap_tasklet on interrupt
 * @airq: pointer to adapter interrupt descriptor
 */
static void ap_interrupt_handler(struct airq_struct *airq, bool floating)
{
        inc_irq_stat(IRQIO_APB);
        tasklet_schedule(&ap_tasklet);
}

/**
 * ap_tasklet_fn(): Tasklet to poll all AP devices.
 * @dummy: Unused variable
 *
 * Poll all AP devices on the bus.
 */
static void ap_tasklet_fn(unsigned long dummy)
{
        int bkt;
        struct ap_queue *aq;
        enum ap_wait wait = AP_WAIT_NONE;

        /* Reset the indicator if interrupts are used. Thus new interrupts can
         * be received. Doing it in the beginning of the tasklet is therefor
         * important that no requests on any AP get lost.
         */
        if (ap_using_interrupts())
                xchg(ap_airq.lsi_ptr, 0);

        spin_lock_bh(&ap_queues_lock);
        hash_for_each(ap_queues, bkt, aq, hnode) {
                spin_lock_bh(&aq->lock);
                wait = min(wait, ap_sm_event_loop(aq, AP_EVENT_POLL));
                spin_unlock_bh(&aq->lock);
        }
        spin_unlock_bh(&ap_queues_lock);

        ap_wait(wait);
}

static int ap_pending_requests(void)
{
        int bkt;
        struct ap_queue *aq;

        spin_lock_bh(&ap_queues_lock);
        hash_for_each(ap_queues, bkt, aq, hnode) {
                if (aq->queue_count == 0)
                        continue;
                spin_unlock_bh(&ap_queues_lock);
                return 1;
        }
        spin_unlock_bh(&ap_queues_lock);
        return 0;
}

/**
 * ap_poll_thread(): Thread that polls for finished requests.
 * @data: Unused pointer
 *
 * AP bus poll thread. The purpose of this thread is to poll for
 * finished requests in a loop if there is a "free" cpu - that is
 * a cpu that doesn't have anything better to do. The polling stops
 * as soon as there is another task or if all messages have been
 * delivered.
 */
static int ap_poll_thread(void *data)
{
        DECLARE_WAITQUEUE(wait, current);

        set_user_nice(current, MAX_NICE);
        set_freezable();
        while (!kthread_should_stop()) {
                add_wait_queue(&ap_poll_wait, &wait);
                set_current_state(TASK_INTERRUPTIBLE);
                if (!ap_pending_requests()) {
                        schedule();
                        try_to_freeze();
                }
                set_current_state(TASK_RUNNING);
                remove_wait_queue(&ap_poll_wait, &wait);
                if (need_resched()) {
                        schedule();
                        try_to_freeze();
                        continue;
                }
                ap_tasklet_fn(0);
        }

        return 0;
}

static int ap_poll_thread_start(void)
{
        int rc;

        if (ap_using_interrupts() || ap_poll_kthread)
                return 0;
        mutex_lock(&ap_poll_thread_mutex);
        ap_poll_kthread = kthread_run(ap_poll_thread, NULL, "appoll");
        rc = PTR_ERR_OR_ZERO(ap_poll_kthread);
        if (rc)
                ap_poll_kthread = NULL;
        mutex_unlock(&ap_poll_thread_mutex);
        return rc;
}

static void ap_poll_thread_stop(void)
{
        if (!ap_poll_kthread)
                return;
        mutex_lock(&ap_poll_thread_mutex);
        kthread_stop(ap_poll_kthread);
        ap_poll_kthread = NULL;
        mutex_unlock(&ap_poll_thread_mutex);
}

#define is_card_dev(x) ((x)->parent == ap_root_device)
#define is_queue_dev(x) ((x)->parent != ap_root_device)

/**
 * ap_bus_match()
 * @dev: Pointer to device
 * @drv: Pointer to device_driver
 *
 * AP bus driver registration/unregistration.
 */
static int ap_bus_match(struct device *dev, struct device_driver *drv)
{
        struct ap_driver *ap_drv = to_ap_drv(drv);
        struct ap_device_id *id;

        /*
         * Compare device type of the device with the list of
         * supported types of the device_driver.
         */
        for (id = ap_drv->ids; id->match_flags; id++) {
                if (is_card_dev(dev) &&
                    id->match_flags & AP_DEVICE_ID_MATCH_CARD_TYPE &&
                    id->dev_type == to_ap_dev(dev)->device_type)
                        return 1;
                if (is_queue_dev(dev) &&
                    id->match_flags & AP_DEVICE_ID_MATCH_QUEUE_TYPE &&
                    id->dev_type == to_ap_dev(dev)->device_type)
                        return 1;
        }
        return 0;
}

/**
 * ap_uevent(): Uevent function for AP devices.
 * @dev: Pointer to device
 * @env: Pointer to kobj_uevent_env
 *
 * It sets up a single environment variable DEV_TYPE which contains the
 * hardware device type.
 */
static int ap_uevent(struct device *dev, struct kobj_uevent_env *env)
{
        struct ap_device *ap_dev = to_ap_dev(dev);
        int retval = 0;

        if (!ap_dev)
                return -ENODEV;

        /* Set up DEV_TYPE environment variable. */
        retval = add_uevent_var(env, "DEV_TYPE=%04X", ap_dev->device_type);
        if (retval)
                return retval;

        /* Add MODALIAS= */
        retval = add_uevent_var(env, "MODALIAS=ap:t%02X", ap_dev->device_type);

        return retval;
}

static int __ap_queue_devices_with_id_unregister(struct device *dev, void *data)
{
        if (is_queue_dev(dev) &&
            AP_QID_CARD(to_ap_queue(dev)->qid) == (int)(long) data)
                device_unregister(dev);
        return 0;
}

static struct bus_type ap_bus_type = {
        .name = "ap",
        .match = &ap_bus_match,
        .uevent = &ap_uevent,
};

static int __ap_revise_reserved(struct device *dev, void *dummy)
{
        int rc, card, queue, devres, drvres;

        if (is_queue_dev(dev)) {
                card = AP_QID_CARD(to_ap_queue(dev)->qid);
                queue = AP_QID_QUEUE(to_ap_queue(dev)->qid);
                mutex_lock(&ap_perms_mutex);
                devres = test_bit_inv(card, ap_perms.apm)
                        && test_bit_inv(queue, ap_perms.aqm);
                mutex_unlock(&ap_perms_mutex);
                drvres = to_ap_drv(dev->driver)->flags
                        & AP_DRIVER_FLAG_DEFAULT;
                if (!!devres != !!drvres) {
                        AP_DBF(DBF_DEBUG, "reprobing queue=%02x.%04x\n",
                               card, queue);
                        rc = device_reprobe(dev);
                }
        }

        return 0;
}

static void ap_bus_revise_bindings(void)
{
        bus_for_each_dev(&ap_bus_type, NULL, NULL, __ap_revise_reserved);
}

int ap_owned_by_def_drv(int card, int queue)
{
        int rc = 0;

        if (card < 0 || card >= AP_DEVICES || queue < 0 || queue >= AP_DOMAINS)
                return -EINVAL;

        mutex_lock(&ap_perms_mutex);

        if (test_bit_inv(card, ap_perms.apm)
            && test_bit_inv(queue, ap_perms.aqm))
                rc = 1;

        mutex_unlock(&ap_perms_mutex);

        return rc;
}
EXPORT_SYMBOL(ap_owned_by_def_drv);

int ap_apqn_in_matrix_owned_by_def_drv(unsigned long *apm,
                                       unsigned long *aqm)
{
        int card, queue, rc = 0;

        mutex_lock(&ap_perms_mutex);

        for (card = 0; !rc && card < AP_DEVICES; card++)
                if (test_bit_inv(card, apm) &&
                    test_bit_inv(card, ap_perms.apm))
                        for (queue = 0; !rc && queue < AP_DOMAINS; queue++)
                                if (test_bit_inv(queue, aqm) &&
                                    test_bit_inv(queue, ap_perms.aqm))
                                        rc = 1;

        mutex_unlock(&ap_perms_mutex);

        return rc;
}
EXPORT_SYMBOL(ap_apqn_in_matrix_owned_by_def_drv);

static int ap_device_probe(struct device *dev)
{
        struct ap_device *ap_dev = to_ap_dev(dev);
        struct ap_driver *ap_drv = to_ap_drv(dev->driver);
        int card, queue, devres, drvres, rc;

        if (is_queue_dev(dev)) {
                /*
                 * If the apqn is marked as reserved/used by ap bus and
                 * default drivers, only probe with drivers with the default
                 * flag set. If it is not marked, only probe with drivers
                 * with the default flag not set.
                 */
                card = AP_QID_CARD(to_ap_queue(dev)->qid);
                queue = AP_QID_QUEUE(to_ap_queue(dev)->qid);
                mutex_lock(&ap_perms_mutex);
                devres = test_bit_inv(card, ap_perms.apm)
                        && test_bit_inv(queue, ap_perms.aqm);
                mutex_unlock(&ap_perms_mutex);
                drvres = ap_drv->flags & AP_DRIVER_FLAG_DEFAULT;
                if (!!devres != !!drvres)
                        return -ENODEV;
        }

        /* Add queue/card to list of active queues/cards */
        spin_lock_bh(&ap_queues_lock);
        if (is_queue_dev(dev))
                hash_add(ap_queues, &to_ap_queue(dev)->hnode,
                         to_ap_queue(dev)->qid);
        spin_unlock_bh(&ap_queues_lock);

        ap_dev->drv = ap_drv;
        rc = ap_drv->probe ? ap_drv->probe(ap_dev) : -ENODEV;

        if (rc) {
                spin_lock_bh(&ap_queues_lock);
                if (is_queue_dev(dev))
                        hash_del(&to_ap_queue(dev)->hnode);
                spin_unlock_bh(&ap_queues_lock);
                ap_dev->drv = NULL;
        }

        return rc;
}

static int ap_device_remove(struct device *dev)
{
        struct ap_device *ap_dev = to_ap_dev(dev);
        struct ap_driver *ap_drv = ap_dev->drv;

        /* prepare ap queue device removal */
        if (is_queue_dev(dev))
                ap_queue_prepare_remove(to_ap_queue(dev));

        /* driver's chance to clean up gracefully */
        if (ap_drv->remove)
                ap_drv->remove(ap_dev);

        /* now do the ap queue device remove */
        if (is_queue_dev(dev))
                ap_queue_remove(to_ap_queue(dev));

        /* Remove queue/card from list of active queues/cards */
        spin_lock_bh(&ap_queues_lock);
        if (is_queue_dev(dev))
                hash_del(&to_ap_queue(dev)->hnode);
        spin_unlock_bh(&ap_queues_lock);

        return 0;
}

struct ap_queue *ap_get_qdev(ap_qid_t qid)
{
        int bkt;
        struct ap_queue *aq;

        spin_lock_bh(&ap_queues_lock);
        hash_for_each(ap_queues, bkt, aq, hnode) {
                if (aq->qid == qid) {
                        get_device(&aq->ap_dev.device);
                        spin_unlock_bh(&ap_queues_lock);
                        return aq;
                }
        }
        spin_unlock_bh(&ap_queues_lock);

        return NULL;
}
EXPORT_SYMBOL(ap_get_qdev);

int ap_driver_register(struct ap_driver *ap_drv, struct module *owner,
                       char *name)
{
        struct device_driver *drv = &ap_drv->driver;

        if (!initialised)
                return -ENODEV;

        drv->bus = &ap_bus_type;
        drv->probe = ap_device_probe;
        drv->remove = ap_device_remove;
        drv->owner = owner;
        drv->name = name;
        return driver_register(drv);
}
EXPORT_SYMBOL(ap_driver_register);

void ap_driver_unregister(struct ap_driver *ap_drv)
{
        driver_unregister(&ap_drv->driver);
}
EXPORT_SYMBOL(ap_driver_unregister);

void ap_bus_force_rescan(void)
{
        /* processing a asynchronous bus rescan */
        del_timer(&ap_config_timer);
        queue_work(system_long_wq, &ap_scan_work);
        flush_work(&ap_scan_work);
}
EXPORT_SYMBOL(ap_bus_force_rescan);

/*
* A config change has happened, force an ap bus rescan.
*/
void ap_bus_cfg_chg(void)
{
        AP_DBF(DBF_INFO, "%s config change, forcing bus rescan\n", __func__);

        ap_bus_force_rescan();
}

/*
 * hex2bitmap() - parse hex mask string and set bitmap.
 * Valid strings are "0x012345678" with at least one valid hex number.
 * Rest of the bitmap to the right is padded with 0. No spaces allowed
 * within the string, the leading 0x may be omitted.
 * Returns the bitmask with exactly the bits set as given by the hex
 * string (both in big endian order).
 */
static int hex2bitmap(const char *str, unsigned long *bitmap, int bits)
{
        int i, n, b;

        /* bits needs to be a multiple of 8 */
        if (bits & 0x07)
                return -EINVAL;

        if (str[0] == '0' && str[1] == 'x')
                str++;
        if (*str == 'x')
                str++;

        for (i = 0; isxdigit(*str) && i < bits; str++) {
                b = hex_to_bin(*str);
                for (n = 0; n < 4; n++)
                        if (b & (0x08 >> n))
                                set_bit_inv(i + n, bitmap);
                i += 4;
        }

        if (*str == '\n')
                str++;
        if (*str)
                return -EINVAL;
        return 0;
}

/*
 * modify_bitmap() - parse bitmask argument and modify an existing
 * bit mask accordingly. A concatenation (done with ',') of these
 * terms is recognized:
 *   +<bitnr>[-<bitnr>] or -<bitnr>[-<bitnr>]
 * <bitnr> may be any valid number (hex, decimal or octal) in the range
 * 0...bits-1; the leading + or - is required. Here are some examples:
 *   +0-15,+32,-128,-0xFF
 *   -0-255,+1-16,+0x128
 *   +1,+2,+3,+4,-5,-7-10
 * Returns the new bitmap after all changes have been applied. Every
 * positive value in the string will set a bit and every negative value
 * in the string will clear a bit. As a bit may be touched more than once,
 * the last 'operation' wins:
 * +0-255,-128 = first bits 0-255 will be set, then bit 128 will be
 * cleared again. All other bits are unmodified.
 */
static int modify_bitmap(const char *str, unsigned long *bitmap, int bits)
{
        int a, i, z;
        char *np, sign;

        /* bits needs to be a multiple of 8 */
        if (bits & 0x07)
                return -EINVAL;

        while (*str) {
                sign = *str++;
                if (sign != '+' && sign != '-')
                        return -EINVAL;
                a = z = simple_strtoul(str, &np, 0);
                if (str == np || a >= bits)
                        return -EINVAL;
                str = np;
                if (*str == '-') {
                        z = simple_strtoul(++str, &np, 0);
                        if (str == np || a > z || z >= bits)
                                return -EINVAL;
                        str = np;
                }
                for (i = a; i <= z; i++)
                        if (sign == '+')
                                set_bit_inv(i, bitmap);
                        else
                                clear_bit_inv(i, bitmap);
                while (*str == ',' || *str == '\n')
                        str++;
        }

        return 0;
}

int ap_parse_mask_str(const char *str,
                      unsigned long *bitmap, int bits,
                      struct mutex *lock)
{
        unsigned long *newmap, size;
        int rc;

        /* bits needs to be a multiple of 8 */
        if (bits & 0x07)
                return -EINVAL;

        size = BITS_TO_LONGS(bits)*sizeof(unsigned long);
        newmap = kmalloc(size, GFP_KERNEL);
        if (!newmap)
                return -ENOMEM;
        if (mutex_lock_interruptible(lock)) {
                kfree(newmap);
                return -ERESTARTSYS;
        }

        if (*str == '+' || *str == '-') {
                memcpy(newmap, bitmap, size);
                rc = modify_bitmap(str, newmap, bits);
        } else {
                memset(newmap, 0, size);
                rc = hex2bitmap(str, newmap, bits);
        }
        if (rc == 0)
                memcpy(bitmap, newmap, size);
        mutex_unlock(lock);
        kfree(newmap);
        return rc;
}
EXPORT_SYMBOL(ap_parse_mask_str);

/*
 * AP bus attributes.
 */

static ssize_t ap_domain_show(struct bus_type *bus, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", ap_domain_index);
}

static ssize_t ap_domain_store(struct bus_type *bus,
                               const char *buf, size_t count)
{
        int domain;

        if (sscanf(buf, "%i\n", &domain) != 1 ||
            domain < 0 || domain > ap_max_domain_id ||
            !test_bit_inv(domain, ap_perms.aqm))
                return -EINVAL;
        spin_lock_bh(&ap_domain_lock);
        ap_domain_index = domain;
        spin_unlock_bh(&ap_domain_lock);

        AP_DBF(DBF_DEBUG, "stored new default domain=%d\n", domain);

        return count;
}

static BUS_ATTR_RW(ap_domain);

static ssize_t ap_control_domain_mask_show(struct bus_type *bus, char *buf)
{
        if (!ap_configuration)  /* QCI not supported */
                return scnprintf(buf, PAGE_SIZE, "not supported\n");

        return scnprintf(buf, PAGE_SIZE,
                         "0x%08x%08x%08x%08x%08x%08x%08x%08x\n",
                         ap_configuration->adm[0], ap_configuration->adm[1],
                         ap_configuration->adm[2], ap_configuration->adm[3],
                         ap_configuration->adm[4], ap_configuration->adm[5],
                         ap_configuration->adm[6], ap_configuration->adm[7]);
}

static BUS_ATTR_RO(ap_control_domain_mask);

static ssize_t ap_usage_domain_mask_show(struct bus_type *bus, char *buf)
{
        if (!ap_configuration)  /* QCI not supported */
                return scnprintf(buf, PAGE_SIZE, "not supported\n");

        return scnprintf(buf, PAGE_SIZE,
                         "0x%08x%08x%08x%08x%08x%08x%08x%08x\n",
                         ap_configuration->aqm[0], ap_configuration->aqm[1],
                         ap_configuration->aqm[2], ap_configuration->aqm[3],
                         ap_configuration->aqm[4], ap_configuration->aqm[5],
                         ap_configuration->aqm[6], ap_configuration->aqm[7]);
}

static BUS_ATTR_RO(ap_usage_domain_mask);

static ssize_t ap_adapter_mask_show(struct bus_type *bus, char *buf)
{
        if (!ap_configuration)  /* QCI not supported */
                return scnprintf(buf, PAGE_SIZE, "not supported\n");

        return scnprintf(buf, PAGE_SIZE,
                         "0x%08x%08x%08x%08x%08x%08x%08x%08x\n",
                         ap_configuration->apm[0], ap_configuration->apm[1],
                         ap_configuration->apm[2], ap_configuration->apm[3],
                         ap_configuration->apm[4], ap_configuration->apm[5],
                         ap_configuration->apm[6], ap_configuration->apm[7]);
}

static BUS_ATTR_RO(ap_adapter_mask);

static ssize_t ap_interrupts_show(struct bus_type *bus, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n",
                         ap_using_interrupts() ? 1 : 0);
}

static BUS_ATTR_RO(ap_interrupts);

static ssize_t config_time_show(struct bus_type *bus, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", ap_config_time);
}

static ssize_t config_time_store(struct bus_type *bus,
                                 const char *buf, size_t count)
{
        int time;

        if (sscanf(buf, "%d\n", &time) != 1 || time < 5 || time > 120)
                return -EINVAL;
        ap_config_time = time;
        mod_timer(&ap_config_timer, jiffies + ap_config_time * HZ);
        return count;
}

static BUS_ATTR_RW(config_time);

static ssize_t poll_thread_show(struct bus_type *bus, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", ap_poll_kthread ? 1 : 0);
}

static ssize_t poll_thread_store(struct bus_type *bus,
                                 const char *buf, size_t count)
{
        int flag, rc;

        if (sscanf(buf, "%d\n", &flag) != 1)
                return -EINVAL;
        if (flag) {
                rc = ap_poll_thread_start();
                if (rc)
                        count = rc;
        } else
                ap_poll_thread_stop();
        return count;
}

static BUS_ATTR_RW(poll_thread);

static ssize_t poll_timeout_show(struct bus_type *bus, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%llu\n", poll_timeout);
}

static ssize_t poll_timeout_store(struct bus_type *bus, const char *buf,
                                  size_t count)
{
        unsigned long long time;
        ktime_t hr_time;

        /* 120 seconds = maximum poll interval */
        if (sscanf(buf, "%llu\n", &time) != 1 || time < 1 ||
            time > 120000000000ULL)
                return -EINVAL;
        poll_timeout = time;
        hr_time = poll_timeout;

        spin_lock_bh(&ap_poll_timer_lock);
        hrtimer_cancel(&ap_poll_timer);
        hrtimer_set_expires(&ap_poll_timer, hr_time);
        hrtimer_start_expires(&ap_poll_timer, HRTIMER_MODE_ABS);
        spin_unlock_bh(&ap_poll_timer_lock);

        return count;
}

static BUS_ATTR_RW(poll_timeout);

static ssize_t ap_max_domain_id_show(struct bus_type *bus, char *buf)
{
        int max_domain_id;

        if (ap_configuration)
                max_domain_id = ap_max_domain_id ? : -1;
        else
                max_domain_id = 15;
        return scnprintf(buf, PAGE_SIZE, "%d\n", max_domain_id);
}

static BUS_ATTR_RO(ap_max_domain_id);

static ssize_t apmask_show(struct bus_type *bus, char *buf)
{
        int rc;

        if (mutex_lock_interruptible(&ap_perms_mutex))
                return -ERESTARTSYS;
        rc = scnprintf(buf, PAGE_SIZE,
                       "0x%016lx%016lx%016lx%016lx\n",
                       ap_perms.apm[0], ap_perms.apm[1],
                       ap_perms.apm[2], ap_perms.apm[3]);
        mutex_unlock(&ap_perms_mutex);

        return rc;
}

static ssize_t apmask_store(struct bus_type *bus, const char *buf,
                            size_t count)
{
        int rc;

        rc = ap_parse_mask_str(buf, ap_perms.apm, AP_DEVICES, &ap_perms_mutex);
        if (rc)
                return rc;

        ap_bus_revise_bindings();

        return count;
}

static BUS_ATTR_RW(apmask);

static ssize_t aqmask_show(struct bus_type *bus, char *buf)
{
        int rc;

        if (mutex_lock_interruptible(&ap_perms_mutex))
                return -ERESTARTSYS;
        rc = scnprintf(buf, PAGE_SIZE,
                       "0x%016lx%016lx%016lx%016lx\n",
                       ap_perms.aqm[0], ap_perms.aqm[1],
                       ap_perms.aqm[2], ap_perms.aqm[3]);
        mutex_unlock(&ap_perms_mutex);

        return rc;
}

static ssize_t aqmask_store(struct bus_type *bus, const char *buf,
                            size_t count)
{
        int rc;

        rc = ap_parse_mask_str(buf, ap_perms.aqm, AP_DOMAINS, &ap_perms_mutex);
        if (rc)
                return rc;

        ap_bus_revise_bindings();

        return count;
}

static BUS_ATTR_RW(aqmask);

static struct bus_attribute *const ap_bus_attrs[] = {
        &bus_attr_ap_domain,
        &bus_attr_ap_control_domain_mask,
        &bus_attr_ap_usage_domain_mask,
        &bus_attr_ap_adapter_mask,
        &bus_attr_config_time,
        &bus_attr_poll_thread,
        &bus_attr_ap_interrupts,
        &bus_attr_poll_timeout,
        &bus_attr_ap_max_domain_id,
        &bus_attr_apmask,
        &bus_attr_aqmask,
        NULL,
};

/**
 * ap_select_domain(): Select an AP domain if possible and we haven't
 * already done so before.
 */
static void ap_select_domain(void)
{
        int count, max_count, best_domain;
        struct ap_queue_status status;
        int i, j;

        /*
         * We want to use a single domain. Either the one specified with
         * the "domain=" parameter or the domain with the maximum number
         * of devices.
         */
        spin_lock_bh(&ap_domain_lock);
        if (ap_domain_index >= 0) {
                /* Domain has already been selected. */
                spin_unlock_bh(&ap_domain_lock);
                return;
        }
        best_domain = -1;
        max_count = 0;
        for (i = 0; i < AP_DOMAINS; i++) {
                if (!ap_test_config_usage_domain(i) ||
                    !test_bit_inv(i, ap_perms.aqm))
                        continue;
                count = 0;
                for (j = 0; j < AP_DEVICES; j++) {
                        if (!ap_test_config_card_id(j))
                                continue;
                        status = ap_test_queue(AP_MKQID(j, i),
                                               ap_apft_available(),
                                               NULL);
                        if (status.response_code != AP_RESPONSE_NORMAL)
                                continue;
                        count++;
                }
                if (count > max_count) {
                        max_count = count;
                        best_domain = i;
                }
        }
        if (best_domain >= 0) {
                ap_domain_index = best_domain;
                AP_DBF(DBF_DEBUG, "new ap_domain_index=%d\n", ap_domain_index);
        }
        spin_unlock_bh(&ap_domain_lock);
}

/*
 * This function checks the type and returns either 0 for not
 * supported or the highest compatible type value (which may
 * include the input type value).
 */
static int ap_get_compatible_type(ap_qid_t qid, int rawtype, unsigned int func)
{
        int comp_type = 0;

        /* < CEX2A is not supported */
        if (rawtype < AP_DEVICE_TYPE_CEX2A)
                return 0;
        /* up to CEX7 known and fully supported */
        if (rawtype <= AP_DEVICE_TYPE_CEX7)
                return rawtype;
        /*
         * unknown new type > CEX7, check for compatibility
         * to the highest known and supported type which is
         * currently CEX7 with the help of the QACT function.
         */
        if (ap_qact_available()) {
                struct ap_queue_status status;
                union ap_qact_ap_info apinfo = {0};

                apinfo.mode = (func >> 26) & 0x07;
                apinfo.cat = AP_DEVICE_TYPE_CEX7;
                status = ap_qact(qid, 0, &apinfo);
                if (status.response_code == AP_RESPONSE_NORMAL
                    && apinfo.cat >= AP_DEVICE_TYPE_CEX2A
                    && apinfo.cat <= AP_DEVICE_TYPE_CEX7)
                        comp_type = apinfo.cat;
        }
        if (!comp_type)
                AP_DBF(DBF_WARN, "queue=%02x.%04x unable to map type %d\n",
                       AP_QID_CARD(qid), AP_QID_QUEUE(qid), rawtype);
        else if (comp_type != rawtype)
                AP_DBF(DBF_INFO, "queue=%02x.%04x map type %d to %d\n",
                       AP_QID_CARD(qid), AP_QID_QUEUE(qid), rawtype, comp_type);
        return comp_type;
}

/*
 * Helper function to be used with bus_find_dev
 * matches for the card device with the given id
 */
static int __match_card_device_with_id(struct device *dev, const void *data)
{
        return is_card_dev(dev) && to_ap_card(dev)->id == (int)(long)(void *) data;
}

/*
 * Helper function to be used with bus_find_dev
 * matches for the queue device with a given qid
 */
static int __match_queue_device_with_qid(struct device *dev, const void *data)
{
        return is_queue_dev(dev) && to_ap_queue(dev)->qid == (int)(long) data;
}

/*
 * Helper function to be used with bus_find_dev
 * matches any queue device with given queue id
 */
static int __match_queue_device_with_queue_id(struct device *dev, const void *data)
{
        return is_queue_dev(dev)
                && AP_QID_QUEUE(to_ap_queue(dev)->qid) == (int)(long) data;
}

/*
 * Helper function for ap_scan_bus().
 * Does the scan bus job for the given adapter id.
 */
static void _ap_scan_bus_adapter(int id)
{
        ap_qid_t qid;
        unsigned int func;
        struct ap_card *ac;
        struct device *dev;
        struct ap_queue *aq;
        int rc, dom, depth, type, comp_type, borked;

        /* check if there is a card device registered with this id */
        dev = bus_find_device(&ap_bus_type, NULL,
                              (void *)(long) id,
                              __match_card_device_with_id);
        ac = dev ? to_ap_card(dev) : NULL;
        if (!ap_test_config_card_id(id)) {
                if (dev) {
                        /* Card device has been removed from configuration */
                        bus_for_each_dev(&ap_bus_type, NULL,
                                         (void *)(long) id,
                                         __ap_queue_devices_with_id_unregister);
                        device_unregister(dev);
                        put_device(dev);
                }
                return;
        }

        /*
         * This card id is enabled in the configuration. If we already have
         * a card device with this id, check if type and functions are still
         * the very same. Also verify that at least one queue is available.
         */
        if (ac) {
                /* find the first valid queue */
                for (dom = 0; dom < AP_DOMAINS; dom++) {
                        qid = AP_MKQID(id, dom);
                        if (ap_query_queue(qid, &depth, &type, &func) == 0)
                                break;
                }
                borked = 0;
                if (dom >= AP_DOMAINS) {
                        /* no accessible queue on this card */
                        borked = 1;
                } else if (ac->raw_hwtype != type) {
                        /* card type has changed */
                        AP_DBF(DBF_INFO, "card=%02x type changed.\n", id);
                        borked = 1;
                } else if (ac->functions != func) {
                        /* card functions have changed */
                        AP_DBF(DBF_INFO, "card=%02x functions changed.\n", id);
                        borked = 1;
                }
                if (borked) {
                        /* unregister card device and associated queues */
                        bus_for_each_dev(&ap_bus_type, NULL,
                                         (void *)(long) id,
                                         __ap_queue_devices_with_id_unregister);
                        device_unregister(dev);
                        put_device(dev);
                        /* go back if there is no valid queue on this card */
                        if (dom >= AP_DOMAINS)
                                return;
                        ac = NULL;
                }
        }

        /*
         * Go through all possible queue ids. Check and maybe create or release
         * queue devices for this card. If there exists no card device yet,
         * create a card device also.
         */
        for (dom = 0; dom < AP_DOMAINS; dom++) {
                qid = AP_MKQID(id, dom);
                dev = bus_find_device(&ap_bus_type, NULL,
                                      (void *)(long) qid,
                                      __match_queue_device_with_qid);
                aq = dev ? to_ap_queue(dev) : NULL;
                if (!ap_test_config_usage_domain(dom)) {
                        if (dev) {
                                /* Queue device exists but has been
                                 * removed from configuration.
                                 */
                                device_unregister(dev);
                                put_device(dev);
                        }
                        continue;
                }
                /* try to fetch infos about this queue */
                rc = ap_query_queue(qid, &depth, &type, &func);
                if (dev) {
                        if (rc == -ENODEV)
                                borked = 1;
                        else {
                                spin_lock_bh(&aq->lock);
                                borked = aq->state == AP_STATE_BORKED;
                                spin_unlock_bh(&aq->lock);
                        }
                        if (borked) {
                                /* Remove broken device */
                                AP_DBF(DBF_DEBUG,
                                       "removing broken queue=%02x.%04x\n",
                                       id, dom);
                                device_unregister(dev);
                        }
                        put_device(dev);
                        continue;
                }
                if (rc)
                        continue;
                /* a new queue device is needed, check out comp type */
                comp_type = ap_get_compatible_type(qid, type, func);
                if (!comp_type)
                        continue;
                /* maybe a card device needs to be created first */
                if (!ac) {
                        ac = ap_card_create(id, depth, type, comp_type, func);
                        if (!ac)
                                continue;
                        ac->ap_dev.device.bus = &ap_bus_type;
                        ac->ap_dev.device.parent = ap_root_device;
                        dev_set_name(&ac->ap_dev.device, "card%02x", id);
                        /* Register card device with AP bus */
                        rc = device_register(&ac->ap_dev.device);
                        if (rc) {
                                put_device(&ac->ap_dev.device);
                                ac = NULL;
                                break;
                        }
                        /* get it and thus adjust reference counter */
                        get_device(&ac->ap_dev.device);
                }
                /* now create the new queue device */
                aq = ap_queue_create(qid, comp_type);
                if (!aq)
                        continue;
                aq->card = ac;
                aq->ap_dev.device.bus = &ap_bus_type;
                aq->ap_dev.device.parent = &ac->ap_dev.device;
                dev_set_name(&aq->ap_dev.device, "%02x.%04x", id, dom);
                /* Register queue device */
                rc = device_register(&aq->ap_dev.device);
                if (rc) {
                        put_device(&aq->ap_dev.device);
                        continue;
                }
        } /* end domain loop */

        if (ac)
                put_device(&ac->ap_dev.device);
}

/**
 * ap_scan_bus(): Scan the AP bus for new devices
 * Runs periodically, workqueue timer (ap_config_time)
 */
static void ap_scan_bus(struct work_struct *unused)
{
        int id;

        AP_DBF(DBF_DEBUG, "%s running\n", __func__);

        ap_query_configuration(ap_configuration);
        ap_select_domain();

        /* loop over all possible adapters */
        for (id = 0; id < AP_DEVICES; id++)
                _ap_scan_bus_adapter(id);

        /* check if there is at least one queue available with default domain */
        if (ap_domain_index >= 0) {
                struct device *dev =
                        bus_find_device(&ap_bus_type, NULL,
                                        (void *)(long) ap_domain_index,
                                        __match_queue_device_with_queue_id);
                if (dev)
                        put_device(dev);
                else
                        AP_DBF(DBF_INFO,
                               "no queue device with default domain %d available\n",
                               ap_domain_index);
        }

        mod_timer(&ap_config_timer, jiffies + ap_config_time * HZ);
}

static void ap_config_timeout(struct timer_list *unused)
{
        queue_work(system_long_wq, &ap_scan_work);
}

static int __init ap_debug_init(void)
{
        ap_dbf_info = debug_register("ap", 1, 1,
                                     DBF_MAX_SPRINTF_ARGS * sizeof(long));
        debug_register_view(ap_dbf_info, &debug_sprintf_view);
        debug_set_level(ap_dbf_info, DBF_ERR);

        return 0;
}

static void __init ap_perms_init(void)
{
        /* all resources useable if no kernel parameter string given */
        memset(&ap_perms.ioctlm, 0xFF, sizeof(ap_perms.ioctlm));
        memset(&ap_perms.apm, 0xFF, sizeof(ap_perms.apm));
        memset(&ap_perms.aqm, 0xFF, sizeof(ap_perms.aqm));

        /* apm kernel parameter string */
        if (apm_str) {
                memset(&ap_perms.apm, 0, sizeof(ap_perms.apm));
                ap_parse_mask_str(apm_str, ap_perms.apm, AP_DEVICES,
                                  &ap_perms_mutex);
        }

        /* aqm kernel parameter string */
        if (aqm_str) {
                memset(&ap_perms.aqm, 0, sizeof(ap_perms.aqm));
                ap_parse_mask_str(aqm_str, ap_perms.aqm, AP_DOMAINS,
                                  &ap_perms_mutex);
        }
}

/**
 * ap_module_init(): The module initialization code.
 *
 * Initializes the module.
 */
static int __init ap_module_init(void)
{
        int max_domain_id;
        int rc, i;

        rc = ap_debug_init();
        if (rc)
                return rc;

        if (!ap_instructions_available()) {
                pr_warn("The hardware system does not support AP instructions\n");
                return -ENODEV;
        }

        /* init ap_queue hashtable */
        hash_init(ap_queues);

        /* set up the AP permissions (ioctls, ap and aq masks) */
        ap_perms_init();

        /* Get AP configuration data if available */
        ap_init_configuration();

        if (ap_configuration)
                max_domain_id =
                        ap_max_domain_id ? ap_max_domain_id : AP_DOMAINS - 1;
        else
                max_domain_id = 15;
        if (ap_domain_index < -1 || ap_domain_index > max_domain_id ||
            (ap_domain_index >= 0 &&
             !test_bit_inv(ap_domain_index, ap_perms.aqm))) {
                pr_warn("%d is not a valid cryptographic domain\n",
                        ap_domain_index);
                ap_domain_index = -1;
        }

        if (ap_interrupts_available()) {
                rc = register_adapter_interrupt(&ap_airq);
                ap_airq_flag = (rc == 0);
        }

        /* Create /sys/bus/ap. */
        rc = bus_register(&ap_bus_type);
        if (rc)
                goto out;
        for (i = 0; ap_bus_attrs[i]; i++) {
                rc = bus_create_file(&ap_bus_type, ap_bus_attrs[i]);
                if (rc)
                        goto out_bus;
        }

        /* Create /sys/devices/ap. */
        ap_root_device = root_device_register("ap");
        rc = PTR_ERR_OR_ZERO(ap_root_device);
        if (rc)
                goto out_bus;

        /* Setup the AP bus rescan timer. */
        timer_setup(&ap_config_timer, ap_config_timeout, 0);

        /*
         * Setup the high resultion poll timer.
         * If we are running under z/VM adjust polling to z/VM polling rate.
         */
        if (MACHINE_IS_VM)
                poll_timeout = 1500000;
        spin_lock_init(&ap_poll_timer_lock);
        hrtimer_init(&ap_poll_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
        ap_poll_timer.function = ap_poll_timeout;

        /* Start the low priority AP bus poll thread. */
        if (ap_thread_flag) {
                rc = ap_poll_thread_start();
                if (rc)
                        goto out_work;
        }

        queue_work(system_long_wq, &ap_scan_work);
        initialised = true;

        return 0;

out_work:
        hrtimer_cancel(&ap_poll_timer);
        root_device_unregister(ap_root_device);
out_bus:
        while (i--)
                bus_remove_file(&ap_bus_type, ap_bus_attrs[i]);
        bus_unregister(&ap_bus_type);
out:
        if (ap_using_interrupts())
                unregister_adapter_interrupt(&ap_airq);
        kfree(ap_configuration);
        return rc;
}
device_initcall(ap_module_init);