// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright IBM Corp. 2006, 2021
 * 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>
 *            Harald Freudenberger <freude@linux.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.");

atomic_t ap_max_msg_size = ATOMIC_INIT(AP_DEFAULT_MAX_MSG_SIZE);
EXPORT_SYMBOL(ap_max_msg_size);

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);

/* # of bus scans since init */
static atomic64_t ap_scan_bus_count;

/* # of bindings complete since init */
static atomic64_t ap_bindings_complete_count = ATOMIC64_INIT(0);

/* completion for initial APQN bindings complete */
static DECLARE_COMPLETION(ap_init_apqn_bindings_complete);

static struct ap_config_info *ap_qci_info;

/*
 * 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_OLD(ap_tasklet, ap_tasklet_fn);
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, if not given via qci */
static int ap_max_domain_id = 15;
/* Maximum adapter id, if not given via qci */
static int ap_max_adapter_id = 63;

static struct bus_type ap_bus_type;

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

static bool ap_irq_flag;

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

/**
 * 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_irq_flag)
                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_qci_available(): Test if AP configuration
 * information can be queried via QCI subfunction.
 *
 * Returns 1 if subfunction PQAP(QCI) is available.
 */
static int ap_qci_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_qci_info)
                return ap_qci_info->qact;
        return 0;
}

/*
 * ap_fetch_qci_info(): 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_fetch_qci_info(struct ap_config_info *info)
{
        if (!ap_qci_available())
                return -EOPNOTSUPP;
        if (!info)
                return -EINVAL;
        return ap_qci(info);
}

/**
 * ap_init_qci_info(): Allocate and query qci config info.
 * Does also update the static variables ap_max_domain_id
 * and ap_max_adapter_id if this info is available.
 */
static void __init ap_init_qci_info(void)
{
        if (!ap_qci_available()) {
                AP_DBF_INFO("%s QCI not supported\n", __func__);
                return;
        }

        ap_qci_info = kzalloc(sizeof(*ap_qci_info), GFP_KERNEL);
        if (!ap_qci_info)
                return;
        if (ap_fetch_qci_info(ap_qci_info) != 0) {
                kfree(ap_qci_info);
                ap_qci_info = NULL;
                return;
        }
        AP_DBF_INFO("%s successful fetched initial qci info\n", __func__);

        if (ap_qci_info->apxa) {
                if (ap_qci_info->Na) {
                        ap_max_adapter_id = ap_qci_info->Na;
                        AP_DBF_INFO("%s new ap_max_adapter_id is %d\n",
                                    __func__, ap_max_adapter_id);
                }
                if (ap_qci_info->Nd) {
                        ap_max_domain_id = ap_qci_info->Nd;
                        AP_DBF_INFO("%s new ap_max_domain_id is %d\n",
                                    __func__, ap_max_domain_id);
                }
        }
}

/*
 * 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.
 *
 * 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 (id > ap_max_adapter_id)
                return 0;
        if (ap_qci_info)
                return ap_test_config(ap_qci_info->apm, id);
        return 1;
}

/*
 * ap_test_config_usage_domain(): Test, whether an AP usage domain
 * is configured.
 *
 * 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 (domain > ap_max_domain_id)
                return 0;
        if (ap_qci_info)
                return ap_test_config(ap_qci_info->aqm, domain);
        return 1;
}
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_qci_info || domain > ap_max_domain_id)
                return 0;
        return ap_test_config(ap_qci_info->adm, domain);
}
EXPORT_SYMBOL(ap_test_config_ctrl_domain);

/*
 * ap_queue_info(): Check and get AP queue info.
 * Returns true if TAPQ succeeded and the info is filled or
 * false otherwise.
 */
static bool ap_queue_info(ap_qid_t qid, int *q_type, unsigned int *q_fac,
                          int *q_depth, int *q_ml, bool *q_decfg)
{
        struct ap_queue_status status;
        union {
                unsigned long value;
                struct {
                        unsigned int fac   : 32; /* facility bits */
                        unsigned int at    :  8; /* ap type */
                        unsigned int _res1 :  8;
                        unsigned int _res2 :  4;
                        unsigned int ml    :  4; /* apxl ml */
                        unsigned int _res3 :  4;
                        unsigned int qd    :  4; /* queue depth */
                } tapq_gr2;
        } tapq_info;

        tapq_info.value = 0;

        /* make sure we don't run into a specifiation exception */
        if (AP_QID_CARD(qid) > ap_max_adapter_id ||
            AP_QID_QUEUE(qid) > ap_max_domain_id)
                return false;

        /* call TAPQ on this APQN */
        status = ap_test_queue(qid, ap_apft_available(), &tapq_info.value);
        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
        case AP_RESPONSE_RESET_IN_PROGRESS:
        case AP_RESPONSE_DECONFIGURED:
        case AP_RESPONSE_CHECKSTOPPED:
        case AP_RESPONSE_BUSY:
                /*
                 * According to the architecture in all these cases the
                 * info should be filled. All bits 0 is not possible as
                 * there is at least one of the mode bits set.
                 */
                if (WARN_ON_ONCE(!tapq_info.value))
                        return false;
                *q_type = tapq_info.tapq_gr2.at;
                *q_fac = tapq_info.tapq_gr2.fac;
                *q_depth = tapq_info.tapq_gr2.qd;
                *q_ml = tapq_info.tapq_gr2.ml;
                *q_decfg = status.response_code == AP_RESPONSE_DECONFIGURED;
                switch (*q_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:
                        *q_fac |= 0x08000000;
                        break;
                case AP_DEVICE_TYPE_CEX2C:
                case AP_DEVICE_TYPE_CEX3C:
                        *q_fac |= 0x10000000;
                        break;
                default:
                        break;
                }
                return true;
        default:
                /*
                 * A response code which indicates, there is no info available.
                 */
                return false;
        }
}

void ap_wait(enum ap_sm_wait wait)
{
        ktime_t hr_time;

        switch (wait) {
        case AP_SM_WAIT_AGAIN:
        case AP_SM_WAIT_INTERRUPT:
                if (ap_irq_flag)
                        break;
                if (ap_poll_kthread) {
                        wake_up(&ap_poll_wait);
                        break;
                }
                fallthrough;
        case AP_SM_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_SM_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_SM_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
 * @floating: ignored
 */
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_sm_wait wait = AP_SM_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_irq_flag)
                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_SM_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_irq_flag || 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)
{
        int rc = 0;
        struct ap_device *ap_dev = to_ap_dev(dev);

        /* Uevents from ap bus core don't need extensions to the env */
        if (dev == ap_root_device)
                return 0;

        if (is_card_dev(dev)) {
                struct ap_card *ac = to_ap_card(&ap_dev->device);

                /* Set up DEV_TYPE environment variable. */
                rc = add_uevent_var(env, "DEV_TYPE=%04X", ap_dev->device_type);
                if (rc)
                        return rc;
                /* Add MODALIAS= */
                rc = add_uevent_var(env, "MODALIAS=ap:t%02X", ap_dev->device_type);
                if (rc)
                        return rc;

                /* Add MODE=<accel|cca|ep11> */
                if (ap_test_bit(&ac->functions, AP_FUNC_ACCEL))
                        rc = add_uevent_var(env, "MODE=accel");
                else if (ap_test_bit(&ac->functions, AP_FUNC_COPRO))
                        rc = add_uevent_var(env, "MODE=cca");
                else if (ap_test_bit(&ac->functions, AP_FUNC_EP11))
                        rc = add_uevent_var(env, "MODE=ep11");
                if (rc)
                        return rc;
        } else {
                struct ap_queue *aq = to_ap_queue(&ap_dev->device);

                /* Add MODE=<accel|cca|ep11> */
                if (ap_test_bit(&aq->card->functions, AP_FUNC_ACCEL))
                        rc = add_uevent_var(env, "MODE=accel");
                else if (ap_test_bit(&aq->card->functions, AP_FUNC_COPRO))
                        rc = add_uevent_var(env, "MODE=cca");
                else if (ap_test_bit(&aq->card->functions, AP_FUNC_EP11))
                        rc = add_uevent_var(env, "MODE=ep11");
                if (rc)
                        return rc;
        }

        return 0;
}

static void ap_send_init_scan_done_uevent(void)
{
        char *envp[] = { "INITSCAN=done", NULL };

        kobject_uevent_env(&ap_root_device->kobj, KOBJ_CHANGE, envp);
}

static void ap_send_bindings_complete_uevent(void)
{
        char buf[32];
        char *envp[] = { "BINDINGS=complete", buf, NULL };

        snprintf(buf, sizeof(buf), "COMPLETECOUNT=%llu",
                 atomic64_inc_return(&ap_bindings_complete_count));
        kobject_uevent_env(&ap_root_device->kobj, KOBJ_CHANGE, envp);
}

void ap_send_config_uevent(struct ap_device *ap_dev, bool cfg)
{
        char buf[16];
        char *envp[] = { buf, NULL };

        snprintf(buf, sizeof(buf), "CONFIG=%d", cfg ? 1 : 0);

        kobject_uevent_env(&ap_dev->device.kobj, KOBJ_CHANGE, envp);
}
EXPORT_SYMBOL(ap_send_config_uevent);

void ap_send_online_uevent(struct ap_device *ap_dev, int online)
{
        char buf[16];
        char *envp[] = { buf, NULL };

        snprintf(buf, sizeof(buf), "ONLINE=%d", online ? 1 : 0);

        kobject_uevent_env(&ap_dev->device.kobj, KOBJ_CHANGE, envp);
}
EXPORT_SYMBOL(ap_send_online_uevent);

/*
 * calc # of bound APQNs
 */

struct __ap_calc_ctrs {
        unsigned int apqns;
        unsigned int bound;
};

static int __ap_calc_helper(struct device *dev, void *arg)
{
        struct __ap_calc_ctrs *pctrs = (struct __ap_calc_ctrs *) arg;

        if (is_queue_dev(dev)) {
                pctrs->apqns++;
                if (dev->driver)
                        pctrs->bound++;
        }

        return 0;
}

static void ap_calc_bound_apqns(unsigned int *apqns, unsigned int *bound)
{
        struct __ap_calc_ctrs ctrs;

        memset(&ctrs, 0, sizeof(ctrs));
        bus_for_each_dev(&ap_bus_type, NULL, (void *) &ctrs, __ap_calc_helper);

        *apqns = ctrs.apqns;
        *bound = ctrs.bound;
}

/*
 * After initial ap bus scan do check if all existing APQNs are
 * bound to device drivers.
 */
static void ap_check_bindings_complete(void)
{
        unsigned int apqns, bound;

        if (atomic64_read(&ap_scan_bus_count) >= 1) {
                ap_calc_bound_apqns(&apqns, &bound);
                if (bound == apqns) {
                        if (!completion_done(&ap_init_apqn_bindings_complete)) {
                                complete_all(&ap_init_apqn_bindings_complete);
                                AP_DBF(DBF_INFO, "%s complete\n", __func__);
                        }
                        ap_send_bindings_complete_uevent();
                }
        }
}

/*
 * Interface to wait for the AP bus to have done one initial ap bus
 * scan and all detected APQNs have been bound to device drivers.
 * If these both conditions are not fulfilled, this function blocks
 * on a condition with wait_for_completion_interruptible_timeout().
 * If these both conditions are fulfilled (before the timeout hits)
 * the return value is 0. If the timeout (in jiffies) hits instead
 * -ETIME is returned. On failures negative return values are
 * returned to the caller.
 */
int ap_wait_init_apqn_bindings_complete(unsigned long timeout)
{
        long l;

        if (completion_done(&ap_init_apqn_bindings_complete))
                return 0;

        if (timeout)
                l = wait_for_completion_interruptible_timeout(
                        &ap_init_apqn_bindings_complete, timeout);
        else
                l = wait_for_completion_interruptible(
                        &ap_init_apqn_bindings_complete);
        if (l < 0)
                return l == -ERESTARTSYS ? -EINTR : l;
        else if (l == 0 && timeout)
                return -ETIME;

        return 0;
}
EXPORT_SYMBOL(ap_wait_init_apqn_bindings_complete);

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 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_DBG("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 = -ENODEV;

        if (!get_device(dev))
                return 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)
                        goto out;
        }

        /* 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);

        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);
        } else
                ap_check_bindings_complete();

out:
        if (rc)
                put_device(dev);
        return rc;
}

static void ap_device_remove(struct device *dev)
{
        struct ap_device *ap_dev = to_ap_dev(dev);
        struct ap_driver *ap_drv = to_ap_drv(dev->driver);

        /* 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);

        put_device(dev);
}

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;

        drv->bus = &ap_bus_type;
        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_DBG("%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_INFO("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_qci_info)       /* 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_qci_info->adm[0], ap_qci_info->adm[1],
                         ap_qci_info->adm[2], ap_qci_info->adm[3],
                         ap_qci_info->adm[4], ap_qci_info->adm[5],
                         ap_qci_info->adm[6], ap_qci_info->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_qci_info)       /* 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_qci_info->aqm[0], ap_qci_info->aqm[1],
                         ap_qci_info->aqm[2], ap_qci_info->aqm[3],
                         ap_qci_info->aqm[4], ap_qci_info->aqm[5],
                         ap_qci_info->aqm[6], ap_qci_info->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_qci_info)       /* 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_qci_info->apm[0], ap_qci_info->apm[1],
                         ap_qci_info->apm[2], ap_qci_info->apm[3],
                         ap_qci_info->apm[4], ap_qci_info->apm[5],
                         ap_qci_info->apm[6], ap_qci_info->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_irq_flag ? 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)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", ap_max_domain_id);
}

static BUS_ATTR_RO(ap_max_domain_id);

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

static BUS_ATTR_RO(ap_max_adapter_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 ssize_t scans_show(struct bus_type *bus, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%llu\n",
                         atomic64_read(&ap_scan_bus_count));
}

static BUS_ATTR_RO(scans);

static ssize_t bindings_show(struct bus_type *bus, char *buf)
{
        int rc;
        unsigned int apqns, n;

        ap_calc_bound_apqns(&apqns, &n);
        if (atomic64_read(&ap_scan_bus_count) >= 1 && n == apqns)
                rc = scnprintf(buf, PAGE_SIZE, "%u/%u (complete)\n", n, apqns);
        else
                rc = scnprintf(buf, PAGE_SIZE, "%u/%u\n", n, apqns);

        return rc;
}

static BUS_ATTR_RO(bindings);

static struct attribute *ap_bus_attrs[] = {
        &bus_attr_ap_domain.attr,
        &bus_attr_ap_control_domain_mask.attr,
        &bus_attr_ap_usage_domain_mask.attr,
        &bus_attr_ap_adapter_mask.attr,
        &bus_attr_config_time.attr,
        &bus_attr_poll_thread.attr,
        &bus_attr_ap_interrupts.attr,
        &bus_attr_poll_timeout.attr,
        &bus_attr_ap_max_domain_id.attr,
        &bus_attr_ap_max_adapter_id.attr,
        &bus_attr_apmask.attr,
        &bus_attr_aqmask.attr,
        &bus_attr_scans.attr,
        &bus_attr_bindings.attr,
        NULL,
};
ATTRIBUTE_GROUPS(ap_bus);

static struct bus_type ap_bus_type = {
        .name = "ap",
        .bus_groups = ap_bus_groups,
        .match = &ap_bus_match,
        .uevent = &ap_uevent,
        .probe = ap_device_probe,
        .remove = ap_device_remove,
};

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

        /*
         * Choose the default domain. Either the one specified with
         * the "domain=" parameter or the first domain with at least
         * one valid APQN.
         */
        spin_lock_bh(&ap_domain_lock);
        if (ap_domain_index >= 0) {
                /* Domain has already been selected. */
                goto out;
        }
        for (dom = 0; dom <= ap_max_domain_id; dom++) {
                if (!ap_test_config_usage_domain(dom) ||
                    !test_bit_inv(dom, ap_perms.aqm))
                        continue;
                for (card = 0; card <= ap_max_adapter_id; card++) {
                        if (!ap_test_config_card_id(card) ||
                            !test_bit_inv(card, ap_perms.apm))
                                continue;
                        status = ap_test_queue(AP_MKQID(card, dom),
                                               ap_apft_available(),
                                               NULL);
                        if (status.response_code == AP_RESPONSE_NORMAL)
                                break;
                }
                if (card <= ap_max_adapter_id)
                        break;
        }
        if (dom <= ap_max_domain_id) {
                ap_domain_index = dom;
                AP_DBF_INFO("%s new default domain is %d\n",
                            __func__, ap_domain_index);
        }
out:
        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) {
                AP_DBF_WARN("get_comp_type queue=%02x.%04x unsupported type %d\n",
                            AP_QID_CARD(qid), AP_QID_QUEUE(qid), rawtype);
                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_WARN("get_comp_type 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_INFO("get_comp_type 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().
 * Remove card device and associated queue devices.
 */
static inline void ap_scan_rm_card_dev_and_queue_devs(struct ap_card *ac)
{
        bus_for_each_dev(&ap_bus_type, NULL,
                         (void *)(long) ac->id,
                         __ap_queue_devices_with_id_unregister);
        device_unregister(&ac->ap_dev.device);
}

/*
 * Helper function for ap_scan_bus().
 * Does the scan bus job for all the domains within
 * a valid adapter given by an ap_card ptr.
 */
static inline void ap_scan_domains(struct ap_card *ac)
{
        bool decfg;
        ap_qid_t qid;
        unsigned int func;
        struct device *dev;
        struct ap_queue *aq;
        int rc, dom, depth, type, ml;

        /*
         * Go through the configuration for the domains and compare them
         * to the existing queue devices. Also take care of the config
         * and error state for the queue devices.
         */

        for (dom = 0; dom <= ap_max_domain_id; dom++) {
                qid = AP_MKQID(ac->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) {
                                AP_DBF_INFO("%s(%d,%d) not in config any more, rm queue device\n",
                                            __func__, ac->id, dom);
                                device_unregister(dev);
                                put_device(dev);
                        }
                        continue;
                }
                /* domain is valid, get info from this APQN */
                if (!ap_queue_info(qid, &type, &func, &depth, &ml, &decfg)) {
                        if (aq) {
                                AP_DBF_INFO(
                                        "%s(%d,%d) ap_queue_info() not successful, rm queue device\n",
                                        __func__, ac->id, dom);
                                device_unregister(dev);
                                put_device(dev);
                        }
                        continue;
                }
                /* if no queue device exists, create a new one */
                if (!aq) {
                        aq = ap_queue_create(qid, ac->ap_dev.device_type);
                        if (!aq) {
                                AP_DBF_WARN("%s(%d,%d) ap_queue_create() failed\n",
                                            __func__, ac->id, dom);
                                continue;
                        }
                        aq->card = ac;
                        aq->config = !decfg;
                        dev = &aq->ap_dev.device;
                        dev->bus = &ap_bus_type;
                        dev->parent = &ac->ap_dev.device;
                        dev_set_name(dev, "%02x.%04x", ac->id, dom);
                        /* register queue device */
                        rc = device_register(dev);
                        if (rc) {
                                AP_DBF_WARN("%s(%d,%d) device_register() failed\n",
                                            __func__, ac->id, dom);
                                goto put_dev_and_continue;
                        }
                        /* get it and thus adjust reference counter */
                        get_device(dev);
                        if (decfg)
                                AP_DBF_INFO("%s(%d,%d) new (decfg) queue device created\n",
                                            __func__, ac->id, dom);
                        else
                                AP_DBF_INFO("%s(%d,%d) new queue device created\n",
                                            __func__, ac->id, dom);
                        goto put_dev_and_continue;
                }
                /* Check config state on the already existing queue device */
                spin_lock_bh(&aq->lock);
                if (decfg && aq->config) {
                        /* config off this queue device */
                        aq->config = false;
                        if (aq->dev_state > AP_DEV_STATE_UNINITIATED) {
                                aq->dev_state = AP_DEV_STATE_ERROR;
                                aq->last_err_rc = AP_RESPONSE_DECONFIGURED;
                        }
                        spin_unlock_bh(&aq->lock);
                        AP_DBF_INFO("%s(%d,%d) queue device config off\n",
                                    __func__, ac->id, dom);
                        ap_send_config_uevent(&aq->ap_dev, aq->config);
                        /* 'receive' pending messages with -EAGAIN */
                        ap_flush_queue(aq);
                        goto put_dev_and_continue;
                }
                if (!decfg && !aq->config) {
                        /* config on this queue device */
                        aq->config = true;
                        if (aq->dev_state > AP_DEV_STATE_UNINITIATED) {
                                aq->dev_state = AP_DEV_STATE_OPERATING;
                                aq->sm_state = AP_SM_STATE_RESET_START;
                        }
                        spin_unlock_bh(&aq->lock);
                        AP_DBF_INFO("%s(%d,%d) queue device config on\n",
                                    __func__, ac->id, dom);
                        ap_send_config_uevent(&aq->ap_dev, aq->config);
                        goto put_dev_and_continue;
                }
                /* handle other error states */
                if (!decfg && aq->dev_state == AP_DEV_STATE_ERROR) {
                        spin_unlock_bh(&aq->lock);
                        /* 'receive' pending messages with -EAGAIN */
                        ap_flush_queue(aq);
                        /* re-init (with reset) the queue device */
                        ap_queue_init_state(aq);
                        AP_DBF_INFO("%s(%d,%d) queue device reinit enforced\n",
                                    __func__, ac->id, dom);
                        goto put_dev_and_continue;
                }
                spin_unlock_bh(&aq->lock);
put_dev_and_continue:
                put_device(dev);
        }
}

/*
 * Helper function for ap_scan_bus().
 * Does the scan bus job for the given adapter id.
 */
static inline void ap_scan_adapter(int ap)
{
        bool decfg;
        ap_qid_t qid;
        unsigned int func;
        struct device *dev;
        struct ap_card *ac;
        int rc, dom, depth, type, comp_type, ml;

        /* Is there currently a card device for this adapter ? */
        dev = bus_find_device(&ap_bus_type, NULL,
                              (void *)(long) ap,
                              __match_card_device_with_id);
        ac = dev ? to_ap_card(dev) : NULL;

        /* Adapter not in configuration ? */
        if (!ap_test_config_card_id(ap)) {
                if (ac) {
                        AP_DBF_INFO("%s(%d) ap not in config any more, rm card and queue devices\n",
                                    __func__, ap);
                        ap_scan_rm_card_dev_and_queue_devs(ac);
                        put_device(dev);
                }
                return;
        }

        /*
         * Adapter ap is valid in the current configuration. So do some checks:
         * If no card device exists, build one. If a card device exists, check
         * for type and functions changed. For all this we need to find a valid
         * APQN first.
         */

        for (dom = 0; dom <= ap_max_domain_id; dom++)
                if (ap_test_config_usage_domain(dom)) {
                        qid = AP_MKQID(ap, dom);
                        if (ap_queue_info(qid, &type, &func,
                                          &depth, &ml, &decfg))
                                break;
                }
        if (dom > ap_max_domain_id) {
                /* Could not find a valid APQN for this adapter */
                if (ac) {
                        AP_DBF_INFO(
                                "%s(%d) no type info (no APQN found), rm card and queue devices\n",
                                __func__, ap);
                        ap_scan_rm_card_dev_and_queue_devs(ac);
                        put_device(dev);
                } else {
                        AP_DBF_DBG("%s(%d) no type info (no APQN found), ignored\n",
                                   __func__, ap);
                }
                return;
        }
        if (!type) {
                /* No apdater type info available, an unusable adapter */
                if (ac) {
                        AP_DBF_INFO("%s(%d) no valid type (0) info, rm card and queue devices\n",
                                    __func__, ap);
                        ap_scan_rm_card_dev_and_queue_devs(ac);
                        put_device(dev);
                } else {
                        AP_DBF_DBG("%s(%d) no valid type (0) info, ignored\n",
                                   __func__, ap);
                }
                return;
        }

        if (ac) {
                /* Check APQN against existing card device for changes */
                if (ac->raw_hwtype != type) {
                        AP_DBF_INFO("%s(%d) hwtype %d changed, rm card and queue devices\n",
                                    __func__, ap, type);
                        ap_scan_rm_card_dev_and_queue_devs(ac);
                        put_device(dev);
                        ac = NULL;
                } else if (ac->functions != func) {
                        AP_DBF_INFO("%s(%d) functions 0x%08x changed, rm card and queue devices\n",
                                    __func__, ap, type);
                        ap_scan_rm_card_dev_and_queue_devs(ac);
                        put_device(dev);
                        ac = NULL;
                } else {
                        if (decfg && ac->config) {
                                ac->config = false;
                                AP_DBF_INFO("%s(%d) card device config off\n",
                                            __func__, ap);
                                ap_send_config_uevent(&ac->ap_dev, ac->config);
                        }
                        if (!decfg && !ac->config) {
                                ac->config = true;
                                AP_DBF_INFO("%s(%d) card device config on\n",
                                            __func__, ap);
                                ap_send_config_uevent(&ac->ap_dev, ac->config);
                        }
                }
        }

        if (!ac) {
                /* Build a new card device */
                comp_type = ap_get_compatible_type(qid, type, func);
                if (!comp_type) {
                        AP_DBF_WARN("%s(%d) type %d, can't get compatibility type\n",
                                    __func__, ap, type);
                        return;
                }
                ac = ap_card_create(ap, depth, type, comp_type, func, ml);
                if (!ac) {
                        AP_DBF_WARN("%s(%d) ap_card_create() failed\n",
                                    __func__, ap);
                        return;
                }
                ac->config = !decfg;
                dev = &ac->ap_dev.device;
                dev->bus = &ap_bus_type;
                dev->parent = ap_root_device;
                dev_set_name(dev, "card%02x", ap);
                /* maybe enlarge ap_max_msg_size to support this card */
                if (ac->maxmsgsize > atomic_read(&ap_max_msg_size)) {
                        atomic_set(&ap_max_msg_size, ac->maxmsgsize);
                        AP_DBF_INFO("%s(%d) ap_max_msg_size update to %d byte\n",
                                    __func__, ap, atomic_read(&ap_max_msg_size));
                }
                /* Register the new card device with AP bus */
                rc = device_register(dev);
                if (rc) {
                        AP_DBF_WARN("%s(%d) device_register() failed\n",
                                    __func__, ap);
                        put_device(dev);
                        return;
                }
                /* get it and thus adjust reference counter */
                get_device(dev);
                if (decfg)
                        AP_DBF_INFO("%s(%d) new (decfg) card device type=%d func=0x%08x created\n",
                                    __func__, ap, type, func);
                else
                        AP_DBF_INFO("%s(%d) new card device type=%d func=0x%08x created\n",
                                    __func__, ap, type, func);
        }

        /* Verify the domains and the queue devices for this card */
        ap_scan_domains(ac);

        /* release the card device */
        put_device(&ac->ap_dev.device);
}

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

        ap_fetch_qci_info(ap_qci_info);
        ap_select_domain();

        AP_DBF_DBG("%s running\n", __func__);

        /* loop over all possible adapters */
        for (ap = 0; ap <= ap_max_adapter_id; ap++)
                ap_scan_adapter(ap);

        /* 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_INFO("no queue device with default domain %d available\n",
                                    ap_domain_index);
        }

        if (atomic64_inc_return(&ap_scan_bus_count) == 1) {
                AP_DBF(DBF_DEBUG, "%s init scan complete\n", __func__);
                ap_send_init_scan_done_uevent();
                ap_check_bindings_complete();
        }

        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 rc;

        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_qci_info();

        /* check default domain setting */
        if (ap_domain_index < -1 || ap_domain_index > ap_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;
        }

        /* enable interrupts if available */
        if (ap_interrupts_available()) {
                rc = register_adapter_interrupt(&ap_airq);
                ap_irq_flag = (rc == 0);
        }

        /* Create /sys/bus/ap. */
        rc = bus_register(&ap_bus_type);
        if (rc)
                goto out;

        /* Create /sys/devices/ap. */
        ap_root_device = root_device_register("ap");
        rc = PTR_ERR_OR_ZERO(ap_root_device);
        if (rc)
                goto out_bus;
        ap_root_device->bus = &ap_bus_type;

        /* 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;
        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);

        return 0;

out_work:
        hrtimer_cancel(&ap_poll_timer);
        root_device_unregister(ap_root_device);
out_bus:
        bus_unregister(&ap_bus_type);
out:
        if (ap_irq_flag)
                unregister_adapter_interrupt(&ap_airq);
        kfree(ap_qci_info);
        return rc;
}
device_initcall(ap_module_init);