ap_bus.c

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/*
 * Copyright IBM Corp. 2006, 2012
 * Author(s): Cornelia Huck <[email protected]>
 *        Martin Schwidefsky <[email protected]>
 *        Ralph Wuerthner <[email protected]>
 *        Felix Beck <[email protected]>
 *        Holger Dengler <[email protected]>
 *
 * Adjunct processor bus.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

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

#include <linux/kernel_stat.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/err.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/reset.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 "ap_bus.h"

/* Some prototypes. */
static void ap_scan_bus(struct work_struct *);
static void ap_poll_all(unsigned long);
static enum hrtimer_restart ap_poll_timeout(struct hrtimer *);
static int ap_poll_thread_start(void);
static void ap_poll_thread_stop(void);
static void ap_request_timeout(unsigned long);
static inline void ap_schedule_poll_timer(void);
static int __ap_poll_device(struct ap_device *ap_dev, unsigned long *flags);
static int ap_device_remove(struct device *dev);
static int ap_device_probe(struct device *dev);
static void ap_interrupt_handler(void *unused1, void *unused2);
static void ap_reset(struct ap_device *ap_dev);
static void ap_config_timeout(unsigned long ptr);
static int ap_select_domain(void);
static void ap_query_configuration(void);

/*
 * Module description.
 */
MODULE_AUTHOR("IBM Corporation");
MODULE_DESCRIPTION("Adjunct Processor Bus driver, " \
           "Copyright IBM Corp. 2006, 2012");
MODULE_LICENSE("GPL");

/*
 * Module parameter
 */
int ap_domain_index = -1;   /* Adjunct Processor Domain Index */
module_param_named(domain, ap_domain_index, int, 0000);
MODULE_PARM_DESC(domain, "domain index for ap devices");
EXPORT_SYMBOL(ap_domain_index);

static int ap_thread_flag = 0;
module_param_named(poll_thread, ap_thread_flag, int, 0000);
MODULE_PARM_DESC(poll_thread, "Turn on/off poll thread, default is 0 (off).");

static struct device *ap_root_device = NULL;
static struct ap_config_info *ap_configuration;
static DEFINE_SPINLOCK(ap_device_list_lock);
static LIST_HEAD(ap_device_list);

/*
 * Workqueue & timer for bus rescan.
 */
static struct workqueue_struct *ap_work_queue;
static struct timer_list ap_config_timer;
static int ap_config_time = AP_CONFIG_TIME;
static DECLARE_WORK(ap_config_work, ap_scan_bus);

/*
 * Tasklet & timer for AP request polling and interrupts
 */
static DECLARE_TASKLET(ap_tasklet, ap_poll_all, 0);
static atomic_t ap_poll_requests = ATOMIC_INIT(0);
static DECLARE_WAIT_QUEUE_HEAD(ap_poll_wait);
static struct task_struct *ap_poll_kthread = NULL;
static DEFINE_MUTEX(ap_poll_thread_mutex);
static DEFINE_SPINLOCK(ap_poll_timer_lock);
static void *ap_interrupt_indicator;
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;

/* Suspend flag */
static int ap_suspend_flag;
/* Flag to check if domain was set through module parameter domain=. This is
 * important when supsend and resume is done in a z/VM environment where the
 * domain might change. */
static int user_set_domain = 0;
static struct bus_type ap_bus_type;

static inline int ap_using_interrupts(void)
{
    return ap_interrupt_indicator != NULL;
}

static inline int ap_instructions_available(void)
{
    register unsigned long reg0 asm ("0") = AP_MKQID(0,0);
    register unsigned long reg1 asm ("1") = -ENODEV;
    register unsigned long reg2 asm ("2") = 0UL;

    asm volatile(
        "   .long 0xb2af0000\n"     /* PQAP(TAPQ) */
        "0: la    %1,0\n"
        "1:\n"
        EX_TABLE(0b, 1b)
        : "+d" (reg0), "+d" (reg1), "+d" (reg2) : : "cc" );
    return reg1;
}

static int ap_interrupts_available(void)
{
    return test_facility(2) && test_facility(65);
}

#ifdef CONFIG_64BIT
static int ap_configuration_available(void)
{
    return test_facility(2) && test_facility(12);
}
#endif

static inline struct ap_queue_status
ap_test_queue(ap_qid_t qid, int *queue_depth, int *device_type)
{
    register unsigned long reg0 asm ("0") = qid;
    register struct ap_queue_status reg1 asm ("1");
    register unsigned long reg2 asm ("2") = 0UL;

    asm volatile(".long 0xb2af0000"     /* PQAP(TAPQ) */
             : "+d" (reg0), "=d" (reg1), "+d" (reg2) : : "cc");
    *device_type = (int) (reg2 >> 24);
    *queue_depth = (int) (reg2 & 0xff);
    return reg1;
}

static inline struct ap_queue_status ap_reset_queue(ap_qid_t qid)
{
    register unsigned long reg0 asm ("0") = qid | 0x01000000UL;
    register struct ap_queue_status reg1 asm ("1");
    register unsigned long reg2 asm ("2") = 0UL;

    asm volatile(
        ".long 0xb2af0000"      /* PQAP(RAPQ) */
        : "+d" (reg0), "=d" (reg1), "+d" (reg2) : : "cc");
    return reg1;
}

#ifdef CONFIG_64BIT

static inline struct ap_queue_status
ap_queue_interruption_control(ap_qid_t qid, void *ind)
{
    register unsigned long reg0 asm ("0") = qid | 0x03000000UL;
    register unsigned long reg1_in asm ("1") = 0x0000800000000000UL | AP_ISC;
    register struct ap_queue_status reg1_out asm ("1");
    register void *reg2 asm ("2") = ind;
    asm volatile(
        ".long 0xb2af0000"      /* PQAP(AQIC) */
        : "+d" (reg0), "+d" (reg1_in), "=d" (reg1_out), "+d" (reg2)
        :
        : "cc" );
    return reg1_out;
}
#endif

#ifdef CONFIG_64BIT
static inline struct ap_queue_status
__ap_query_functions(ap_qid_t qid, unsigned int *functions)
{
    register unsigned long reg0 asm ("0") = 0UL | qid | (1UL << 23);
    register struct ap_queue_status reg1 asm ("1") = AP_QUEUE_STATUS_INVALID;
    register unsigned long reg2 asm ("2");

    asm volatile(
        ".long 0xb2af0000\n"        /* PQAP(TAPQ) */
        "0:\n"
        EX_TABLE(0b, 0b)
        : "+d" (reg0), "+d" (reg1), "=d" (reg2)
        :
        : "cc");

    *functions = (unsigned int)(reg2 >> 32);
    return reg1;
}
#endif

#ifdef CONFIG_64BIT
static inline int __ap_query_configuration(struct ap_config_info *config)
{
    register unsigned long reg0 asm ("0") = 0x04000000UL;
    register unsigned long reg1 asm ("1") = -EINVAL;
    register unsigned char *reg2 asm ("2") = (unsigned char *)config;

    asm volatile(
        ".long 0xb2af0000\n"        /* PQAP(QCI) */
        "0: la    %1,0\n"
        "1:\n"
        EX_TABLE(0b, 1b)
        : "+d" (reg0), "+d" (reg1), "+d" (reg2)
        :
        : "cc");

    return reg1;
}
#endif

static int ap_query_functions(ap_qid_t qid, unsigned int *functions)
{
#ifdef CONFIG_64BIT
    struct ap_queue_status status;
    int i;
    status = __ap_query_functions(qid, functions);

    for (i = 0; i < AP_MAX_RESET; i++) {
        if (ap_queue_status_invalid_test(&status))
            return -ENODEV;

        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
            return 0;
        case AP_RESPONSE_RESET_IN_PROGRESS:
        case AP_RESPONSE_BUSY:
            break;
        case AP_RESPONSE_Q_NOT_AVAIL:
        case AP_RESPONSE_DECONFIGURED:
        case AP_RESPONSE_CHECKSTOPPED:
        case AP_RESPONSE_INVALID_ADDRESS:
            return -ENODEV;
        case AP_RESPONSE_OTHERWISE_CHANGED:
            break;
        default:
            break;
        }
        if (i < AP_MAX_RESET - 1) {
            udelay(5);
            status = __ap_query_functions(qid, functions);
        }
    }
    return -EBUSY;
#else
    return -EINVAL;
#endif
}

static int ap_queue_enable_interruption(ap_qid_t qid, void *ind)
{
#ifdef CONFIG_64BIT
    struct ap_queue_status status;
    int t_depth, t_device_type, rc, i;

    rc = -EBUSY;
    status = ap_queue_interruption_control(qid, ind);

    for (i = 0; i < AP_MAX_RESET; i++) {
        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
            if (status.int_enabled)
                return 0;
            break;
        case AP_RESPONSE_RESET_IN_PROGRESS:
        case AP_RESPONSE_BUSY:
            if (i < AP_MAX_RESET - 1) {
                udelay(5);
                status = ap_queue_interruption_control(qid,
                                       ind);
                continue;
            }
            break;
        case AP_RESPONSE_Q_NOT_AVAIL:
        case AP_RESPONSE_DECONFIGURED:
        case AP_RESPONSE_CHECKSTOPPED:
        case AP_RESPONSE_INVALID_ADDRESS:
            return -ENODEV;
        case AP_RESPONSE_OTHERWISE_CHANGED:
            if (status.int_enabled)
                return 0;
            break;
        default:
            break;
        }
        if (i < AP_MAX_RESET - 1) {
            udelay(5);
            status = ap_test_queue(qid, &t_depth, &t_device_type);
        }
    }
    return rc;
#else
    return -EINVAL;
#endif
}

static inline struct ap_queue_status
__ap_send(ap_qid_t qid, unsigned long long psmid, void *msg, size_t length,
      unsigned int special)
{
    typedef struct { char _[length]; } msgblock;
    register unsigned long reg0 asm ("0") = qid | 0x40000000UL;
    register struct ap_queue_status reg1 asm ("1");
    register unsigned long reg2 asm ("2") = (unsigned long) msg;
    register unsigned long reg3 asm ("3") = (unsigned long) length;
    register unsigned long reg4 asm ("4") = (unsigned int) (psmid >> 32);
    register unsigned long reg5 asm ("5") = (unsigned int) psmid;

    if (special == 1)
        reg0 |= 0x400000UL;

    asm volatile (
        "0: .long 0xb2ad0042\n"     /* NQAP */
        "   brc   2,0b"
        : "+d" (reg0), "=d" (reg1), "+d" (reg2), "+d" (reg3)
        : "d" (reg4), "d" (reg5), "m" (*(msgblock *) msg)
        : "cc" );
    return reg1;
}

int ap_send(ap_qid_t qid, unsigned long long psmid, void *msg, size_t length)
{
    struct ap_queue_status status;

    status = __ap_send(qid, psmid, msg, length, 0);
    switch (status.response_code) {
    case AP_RESPONSE_NORMAL:
        return 0;
    case AP_RESPONSE_Q_FULL:
    case AP_RESPONSE_RESET_IN_PROGRESS:
        return -EBUSY;
    case AP_RESPONSE_REQ_FAC_NOT_INST:
        return -EINVAL;
    default:    /* Device is gone. */
        return -ENODEV;
    }
}
EXPORT_SYMBOL(ap_send);

static inline struct ap_queue_status
__ap_recv(ap_qid_t qid, unsigned long long *psmid, void *msg, size_t length)
{
    typedef struct { char _[length]; } msgblock;
    register unsigned long reg0 asm("0") = qid | 0x80000000UL;
    register struct ap_queue_status reg1 asm ("1");
    register unsigned long reg2 asm("2") = 0UL;
    register unsigned long reg4 asm("4") = (unsigned long) msg;
    register unsigned long reg5 asm("5") = (unsigned long) length;
    register unsigned long reg6 asm("6") = 0UL;
    register unsigned long reg7 asm("7") = 0UL;


    asm volatile(
        "0: .long 0xb2ae0064\n"     /* DQAP */
        "   brc   6,0b\n"
        : "+d" (reg0), "=d" (reg1), "+d" (reg2),
        "+d" (reg4), "+d" (reg5), "+d" (reg6), "+d" (reg7),
        "=m" (*(msgblock *) msg) : : "cc" );
    *psmid = (((unsigned long long) reg6) << 32) + reg7;
    return reg1;
}

int ap_recv(ap_qid_t qid, unsigned long long *psmid, void *msg, size_t length)
{
    struct ap_queue_status status;

    status = __ap_recv(qid, psmid, msg, length);
    switch (status.response_code) {
    case AP_RESPONSE_NORMAL:
        return 0;
    case AP_RESPONSE_NO_PENDING_REPLY:
        if (status.queue_empty)
            return -ENOENT;
        return -EBUSY;
    case AP_RESPONSE_RESET_IN_PROGRESS:
        return -EBUSY;
    default:
        return -ENODEV;
    }
}
EXPORT_SYMBOL(ap_recv);

static int ap_query_queue(ap_qid_t qid, int *queue_depth, int *device_type)
{
    struct ap_queue_status status;
    int t_depth, t_device_type, rc, i;

    rc = -EBUSY;
    for (i = 0; i < AP_MAX_RESET; i++) {
        status = ap_test_queue(qid, &t_depth, &t_device_type);
        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
            *queue_depth = t_depth + 1;
            *device_type = t_device_type;
            rc = 0;
            break;
        case AP_RESPONSE_Q_NOT_AVAIL:
            rc = -ENODEV;
            break;
        case AP_RESPONSE_RESET_IN_PROGRESS:
            break;
        case AP_RESPONSE_DECONFIGURED:
            rc = -ENODEV;
            break;
        case AP_RESPONSE_CHECKSTOPPED:
            rc = -ENODEV;
            break;
        case AP_RESPONSE_INVALID_ADDRESS:
            rc = -ENODEV;
            break;
        case AP_RESPONSE_OTHERWISE_CHANGED:
            break;
        case AP_RESPONSE_BUSY:
            break;
        default:
            BUG();
        }
        if (rc != -EBUSY)
            break;
        if (i < AP_MAX_RESET - 1)
            udelay(5);
    }
    return rc;
}

static int ap_init_queue(ap_qid_t qid)
{
    struct ap_queue_status status;
    int rc, dummy, i;

    rc = -ENODEV;
    status = ap_reset_queue(qid);
    for (i = 0; i < AP_MAX_RESET; i++) {
        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
            if (status.queue_empty)
                rc = 0;
            break;
        case AP_RESPONSE_Q_NOT_AVAIL:
        case AP_RESPONSE_DECONFIGURED:
        case AP_RESPONSE_CHECKSTOPPED:
            i = AP_MAX_RESET;   /* return with -ENODEV */
            break;
        case AP_RESPONSE_RESET_IN_PROGRESS:
            rc = -EBUSY;
        case AP_RESPONSE_BUSY:
        default:
            break;
        }
        if (rc != -ENODEV && rc != -EBUSY)
            break;
        if (i < AP_MAX_RESET - 1) {
            udelay(5);
            status = ap_test_queue(qid, &dummy, &dummy);
        }
    }
    if (rc == 0 && ap_using_interrupts()) {
        rc = ap_queue_enable_interruption(qid, ap_interrupt_indicator);
        /* If interruption mode is supported by the machine,
        * but an AP can not be enabled for interruption then
        * the AP will be discarded.    */
        if (rc)
            pr_err("Registering adapter interrupts for "
                   "AP %d failed\n", AP_QID_DEVICE(qid));
    }
    return rc;
}

static void ap_increase_queue_count(struct ap_device *ap_dev)
{
    int timeout = ap_dev->drv->request_timeout;

    ap_dev->queue_count++;
    if (ap_dev->queue_count == 1) {
        mod_timer(&ap_dev->timeout, jiffies + timeout);
        ap_dev->reset = AP_RESET_ARMED;
    }
}

static void ap_decrease_queue_count(struct ap_device *ap_dev)
{
    int timeout = ap_dev->drv->request_timeout;

    ap_dev->queue_count--;
    if (ap_dev->queue_count > 0)
        mod_timer(&ap_dev->timeout, jiffies + timeout);
    else
        /*
         * The timeout timer should to be disabled now - since
         * del_timer_sync() is very expensive, we just tell via the
         * reset flag to ignore the pending timeout timer.
         */
        ap_dev->reset = AP_RESET_IGNORE;
}

/*
 * AP device related attributes.
 */
static ssize_t ap_hwtype_show(struct device *dev,
                  struct device_attribute *attr, char *buf)
{
    struct ap_device *ap_dev = to_ap_dev(dev);
    return snprintf(buf, PAGE_SIZE, "%d\n", ap_dev->device_type);
}

static DEVICE_ATTR(hwtype, 0444, ap_hwtype_show, NULL);
static ssize_t ap_depth_show(struct device *dev, struct device_attribute *attr,
                 char *buf)
{
    struct ap_device *ap_dev = to_ap_dev(dev);
    return snprintf(buf, PAGE_SIZE, "%d\n", ap_dev->queue_depth);
}

static DEVICE_ATTR(depth, 0444, ap_depth_show, NULL);
static ssize_t ap_request_count_show(struct device *dev,
                     struct device_attribute *attr,
                     char *buf)
{
    struct ap_device *ap_dev = to_ap_dev(dev);
    int rc;

    spin_lock_bh(&ap_dev->lock);
    rc = snprintf(buf, PAGE_SIZE, "%d\n", ap_dev->total_request_count);
    spin_unlock_bh(&ap_dev->lock);
    return rc;
}

static DEVICE_ATTR(request_count, 0444, ap_request_count_show, NULL);

static ssize_t ap_requestq_count_show(struct device *dev,
                      struct device_attribute *attr, char *buf)
{
    struct ap_device *ap_dev = to_ap_dev(dev);
    int rc;

    spin_lock_bh(&ap_dev->lock);
    rc = snprintf(buf, PAGE_SIZE, "%d\n", ap_dev->requestq_count);
    spin_unlock_bh(&ap_dev->lock);
    return rc;
}

static DEVICE_ATTR(requestq_count, 0444, ap_requestq_count_show, NULL);

static ssize_t ap_pendingq_count_show(struct device *dev,
                      struct device_attribute *attr, char *buf)
{
    struct ap_device *ap_dev = to_ap_dev(dev);
    int rc;

    spin_lock_bh(&ap_dev->lock);
    rc = snprintf(buf, PAGE_SIZE, "%d\n", ap_dev->pendingq_count);
    spin_unlock_bh(&ap_dev->lock);
    return rc;
}

static DEVICE_ATTR(pendingq_count, 0444, ap_pendingq_count_show, NULL);

static ssize_t ap_modalias_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    return sprintf(buf, "ap:t%02X", to_ap_dev(dev)->device_type);
}

static DEVICE_ATTR(modalias, 0444, ap_modalias_show, NULL);

static ssize_t ap_functions_show(struct device *dev,
                 struct device_attribute *attr, char *buf)
{
    struct ap_device *ap_dev = to_ap_dev(dev);
    return snprintf(buf, PAGE_SIZE, "0x%08X\n", ap_dev->functions);
}

static DEVICE_ATTR(ap_functions, 0444, ap_functions_show, NULL);

static struct attribute *ap_dev_attrs[] = {
    &dev_attr_hwtype.attr,
    &dev_attr_depth.attr,
    &dev_attr_request_count.attr,
    &dev_attr_requestq_count.attr,
    &dev_attr_pendingq_count.attr,
    &dev_attr_modalias.attr,
    &dev_attr_ap_functions.attr,
    NULL
};
static struct attribute_group ap_dev_attr_group = {
    .attrs = ap_dev_attrs
};

static int ap_bus_match(struct device *dev, struct device_driver *drv)
{
    struct ap_device *ap_dev = to_ap_dev(dev);
    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 ((id->match_flags & AP_DEVICE_ID_MATCH_DEVICE_TYPE) &&
            (id->dev_type != ap_dev->device_type))
            continue;
        return 1;
    }
    return 0;
}

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_bus_suspend(struct device *dev, pm_message_t state)
{
    struct ap_device *ap_dev = to_ap_dev(dev);
    unsigned long flags;

    if (!ap_suspend_flag) {
        ap_suspend_flag = 1;

        /* Disable scanning for devices, thus we do not want to scan
         * for them after removing.
         */
        del_timer_sync(&ap_config_timer);
        if (ap_work_queue != NULL) {
            destroy_workqueue(ap_work_queue);
            ap_work_queue = NULL;
        }

        tasklet_disable(&ap_tasklet);
    }
    /* Poll on the device until all requests are finished. */
    do {
        flags = 0;
        spin_lock_bh(&ap_dev->lock);
        __ap_poll_device(ap_dev, &flags);
        spin_unlock_bh(&ap_dev->lock);
    } while ((flags & 1) || (flags & 2));

    spin_lock_bh(&ap_dev->lock);
    ap_dev->unregistered = 1;
    spin_unlock_bh(&ap_dev->lock);

    return 0;
}

static int ap_bus_resume(struct device *dev)
{
    int rc = 0;
    struct ap_device *ap_dev = to_ap_dev(dev);

    if (ap_suspend_flag) {
        ap_suspend_flag = 0;
        if (!ap_interrupts_available())
            ap_interrupt_indicator = NULL;
        ap_query_configuration();
        if (!user_set_domain) {
            ap_domain_index = -1;
            ap_select_domain();
        }
        init_timer(&ap_config_timer);
        ap_config_timer.function = ap_config_timeout;
        ap_config_timer.data = 0;
        ap_config_timer.expires = jiffies + ap_config_time * HZ;
        add_timer(&ap_config_timer);
        ap_work_queue = create_singlethread_workqueue("kapwork");
        if (!ap_work_queue)
            return -ENOMEM;
        tasklet_enable(&ap_tasklet);
        if (!ap_using_interrupts())
            ap_schedule_poll_timer();
        else
            tasklet_schedule(&ap_tasklet);
        if (ap_thread_flag)
            rc = ap_poll_thread_start();
    }
    if (AP_QID_QUEUE(ap_dev->qid) != ap_domain_index) {
        spin_lock_bh(&ap_dev->lock);
        ap_dev->qid = AP_MKQID(AP_QID_DEVICE(ap_dev->qid),
                       ap_domain_index);
        spin_unlock_bh(&ap_dev->lock);
    }
    queue_work(ap_work_queue, &ap_config_work);

    return rc;
}

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

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 rc;

    ap_dev->drv = ap_drv;
    rc = ap_drv->probe ? ap_drv->probe(ap_dev) : -ENODEV;
    if (!rc) {
        spin_lock_bh(&ap_device_list_lock);
        list_add(&ap_dev->list, &ap_device_list);
        spin_unlock_bh(&ap_device_list_lock);
    }
    return rc;
}

static void __ap_flush_queue(struct ap_device *ap_dev)
{
    struct ap_message *ap_msg, *next;

    list_for_each_entry_safe(ap_msg, next, &ap_dev->pendingq, list) {
        list_del_init(&ap_msg->list);
        ap_dev->pendingq_count--;
        ap_msg->receive(ap_dev, ap_msg, ERR_PTR(-ENODEV));
    }
    list_for_each_entry_safe(ap_msg, next, &ap_dev->requestq, list) {
        list_del_init(&ap_msg->list);
        ap_dev->requestq_count--;
        ap_msg->receive(ap_dev, ap_msg, ERR_PTR(-ENODEV));
    }
}

void ap_flush_queue(struct ap_device *ap_dev)
{
    spin_lock_bh(&ap_dev->lock);
    __ap_flush_queue(ap_dev);
    spin_unlock_bh(&ap_dev->lock);
}
EXPORT_SYMBOL(ap_flush_queue);

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;

    ap_flush_queue(ap_dev);
    del_timer_sync(&ap_dev->timeout);
    spin_lock_bh(&ap_device_list_lock);
    list_del_init(&ap_dev->list);
    spin_unlock_bh(&ap_device_list_lock);
    if (ap_drv->remove)
        ap_drv->remove(ap_dev);
    spin_lock_bh(&ap_dev->lock);
    atomic_sub(ap_dev->queue_count, &ap_poll_requests);
    spin_unlock_bh(&ap_dev->lock);
    return 0;
}

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->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)
{
    /* Delete the AP bus rescan timer. */
    del_timer(&ap_config_timer);

    /* processing a synchonuous bus rescan */
    ap_scan_bus(NULL);

    /* Setup the AP bus rescan timer again. */
    ap_config_timer.expires = jiffies + ap_config_time * HZ;
    add_timer(&ap_config_timer);
}
EXPORT_SYMBOL(ap_bus_force_rescan);

/*
 * AP bus attributes.
 */
static ssize_t ap_domain_show(struct bus_type *bus, char *buf)
{
    return snprintf(buf, PAGE_SIZE, "%d\n", ap_domain_index);
}

static BUS_ATTR(ap_domain, 0444, ap_domain_show, NULL);

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

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

static BUS_ATTR(ap_interrupts, 0444, ap_interrupts_show, NULL);

static ssize_t ap_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;
    if (!timer_pending(&ap_config_timer) ||
        !mod_timer(&ap_config_timer, jiffies + ap_config_time * HZ)) {
        ap_config_timer.expires = jiffies + ap_config_time * HZ;
        add_timer(&ap_config_timer);
    }
    return count;
}

static BUS_ATTR(config_time, 0644, ap_config_time_show, ap_config_time_store);

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

static ssize_t ap_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)
            return rc;
    }
    else
        ap_poll_thread_stop();
    return count;
}

static BUS_ATTR(poll_thread, 0644, ap_poll_thread_show, ap_poll_thread_store);

static ssize_t poll_timeout_show(struct bus_type *bus, char *buf)
{
    return snprintf(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 = ktime_set(0, poll_timeout);

    if (!hrtimer_is_queued(&ap_poll_timer) ||
        !hrtimer_forward(&ap_poll_timer, hrtimer_get_expires(&ap_poll_timer), hr_time)) {
        hrtimer_set_expires(&ap_poll_timer, hr_time);
        hrtimer_start_expires(&ap_poll_timer, HRTIMER_MODE_ABS);
    }
    return count;
}

static BUS_ATTR(poll_timeout, 0644, poll_timeout_show, poll_timeout_store);

static struct bus_attribute *const ap_bus_attrs[] = {
    &bus_attr_ap_domain,
    &bus_attr_config_time,
    &bus_attr_poll_thread,
    &bus_attr_ap_interrupts,
    &bus_attr_poll_timeout,
    NULL,
};

static inline int ap_test_config(unsigned int *field, unsigned int nr)
{
    if (nr > 0xFFu)
        return 0;
    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)
        return 1;
    return ap_test_config(ap_configuration->apm, id);
}

/*
 * ap_test_config_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
 */
static inline int ap_test_config_domain(unsigned int domain)
{
    if (!ap_configuration)
        return 1;
    return ap_test_config(ap_configuration->aqm, domain);
}

static void ap_query_configuration(void)
{
#ifdef CONFIG_64BIT
    if (ap_configuration_available()) {
        if (!ap_configuration)
            ap_configuration =
                kzalloc(sizeof(struct ap_config_info),
                    GFP_KERNEL);
        if (ap_configuration)
            __ap_query_configuration(ap_configuration);
    } else
        ap_configuration = NULL;
#else
    ap_configuration = NULL;
#endif
}

static int ap_select_domain(void)
{
    int queue_depth, device_type, count, max_count, best_domain;
    ap_qid_t qid;
    int rc, 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.
     */
    if (ap_domain_index >= 0 && ap_domain_index < AP_DOMAINS)
        /* Domain has already been selected. */
        return 0;
    best_domain = -1;
    max_count = 0;
    for (i = 0; i < AP_DOMAINS; i++) {
        if (!ap_test_config_domain(i))
            continue;
        count = 0;
        for (j = 0; j < AP_DEVICES; j++) {
            if (!ap_test_config_card_id(j))
                continue;
            qid = AP_MKQID(j, i);
            rc = ap_query_queue(qid, &queue_depth, &device_type);
            if (rc)
                continue;
            count++;
        }
        if (count > max_count) {
            max_count = count;
            best_domain = i;
        }
    }
    if (best_domain >= 0){
        ap_domain_index = best_domain;
        return 0;
    }
    return -ENODEV;
}

static int ap_probe_device_type(struct ap_device *ap_dev)
{
    static unsigned char msg[] = {
        0x00,0x06,0x00,0x00,0x00,0x00,0x00,0x00,
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
        0x00,0x00,0x00,0x58,0x00,0x00,0x00,0x00,
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
        0x01,0x00,0x43,0x43,0x41,0x2d,0x41,0x50,
        0x50,0x4c,0x20,0x20,0x20,0x01,0x01,0x01,
        0x00,0x00,0x00,0x00,0x50,0x4b,0x00,0x00,
        0x00,0x00,0x01,0x1c,0x00,0x00,0x00,0x00,
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
        0x00,0x00,0x05,0xb8,0x00,0x00,0x00,0x00,
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
        0x70,0x00,0x41,0x00,0x00,0x00,0x00,0x00,
        0x00,0x00,0x54,0x32,0x01,0x00,0xa0,0x00,
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
        0x00,0x00,0x00,0x00,0xb8,0x05,0x00,0x00,
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
        0x00,0x00,0x0a,0x00,0x00,0x00,0x00,0x00,
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
        0x00,0x00,0x00,0x00,0x00,0x00,0x08,0x00,
        0x49,0x43,0x53,0x46,0x20,0x20,0x20,0x20,
        0x50,0x4b,0x0a,0x00,0x50,0x4b,0x43,0x53,
        0x2d,0x31,0x2e,0x32,0x37,0x00,0x11,0x22,
        0x33,0x44,0x55,0x66,0x77,0x88,0x99,0x00,
        0x11,0x22,0x33,0x44,0x55,0x66,0x77,0x88,
        0x99,0x00,0x11,0x22,0x33,0x44,0x55,0x66,
        0x77,0x88,0x99,0x00,0x11,0x22,0x33,0x44,
        0x55,0x66,0x77,0x88,0x99,0x00,0x11,0x22,
        0x33,0x44,0x55,0x66,0x77,0x88,0x99,0x00,
        0x11,0x22,0x33,0x5d,0x00,0x5b,0x00,0x77,
        0x88,0x1e,0x00,0x00,0x57,0x00,0x00,0x00,
        0x00,0x04,0x00,0x00,0x4f,0x00,0x00,0x00,
        0x03,0x02,0x00,0x00,0x40,0x01,0x00,0x01,
        0xce,0x02,0x68,0x2d,0x5f,0xa9,0xde,0x0c,
        0xf6,0xd2,0x7b,0x58,0x4b,0xf9,0x28,0x68,
        0x3d,0xb4,0xf4,0xef,0x78,0xd5,0xbe,0x66,
        0x63,0x42,0xef,0xf8,0xfd,0xa4,0xf8,0xb0,
        0x8e,0x29,0xc2,0xc9,0x2e,0xd8,0x45,0xb8,
        0x53,0x8c,0x6f,0x4e,0x72,0x8f,0x6c,0x04,
        0x9c,0x88,0xfc,0x1e,0xc5,0x83,0x55,0x57,
        0xf7,0xdd,0xfd,0x4f,0x11,0x36,0x95,0x5d,
    };
    struct ap_queue_status status;
    unsigned long long psmid;
    char *reply;
    int rc, i;

    reply = (void *) get_zeroed_page(GFP_KERNEL);
    if (!reply) {
        rc = -ENOMEM;
        goto out;
    }

    status = __ap_send(ap_dev->qid, 0x0102030405060708ULL,
               msg, sizeof(msg), 0);
    if (status.response_code != AP_RESPONSE_NORMAL) {
        rc = -ENODEV;
        goto out_free;
    }

    /* Wait for the test message to complete. */
    for (i = 0; i < 6; i++) {
        mdelay(300);
        status = __ap_recv(ap_dev->qid, &psmid, reply, 4096);
        if (status.response_code == AP_RESPONSE_NORMAL &&
            psmid == 0x0102030405060708ULL)
            break;
    }
    if (i < 6) {
        /* Got an answer. */
        if (reply[0] == 0x00 && reply[1] == 0x86)
            ap_dev->device_type = AP_DEVICE_TYPE_PCICC;
        else
            ap_dev->device_type = AP_DEVICE_TYPE_PCICA;
        rc = 0;
    } else
        rc = -ENODEV;

out_free:
    free_page((unsigned long) reply);
out:
    return rc;
}

static void ap_interrupt_handler(void *unused1, void *unused2)
{
    kstat_cpu(smp_processor_id()).irqs[IOINT_APB]++;
    tasklet_schedule(&ap_tasklet);
}

static int __ap_scan_bus(struct device *dev, void *data)
{
    return to_ap_dev(dev)->qid == (ap_qid_t)(unsigned long) data;
}

static void ap_device_release(struct device *dev)
{
    struct ap_device *ap_dev = to_ap_dev(dev);

    kfree(ap_dev);
}

static void ap_scan_bus(struct work_struct *unused)
{
    struct ap_device *ap_dev;
    struct device *dev;
    ap_qid_t qid;
    int queue_depth, device_type;
    unsigned int device_functions;
    int rc, i;

    ap_query_configuration();
    if (ap_select_domain() != 0)
        return;
    for (i = 0; i < AP_DEVICES; i++) {
        qid = AP_MKQID(i, ap_domain_index);
        dev = bus_find_device(&ap_bus_type, NULL,
                      (void *)(unsigned long)qid,
                      __ap_scan_bus);
        if (ap_test_config_card_id(i))
            rc = ap_query_queue(qid, &queue_depth, &device_type);
        else
            rc = -ENODEV;
        if (dev) {
            if (rc == -EBUSY) {
                set_current_state(TASK_UNINTERRUPTIBLE);
                schedule_timeout(AP_RESET_TIMEOUT);
                rc = ap_query_queue(qid, &queue_depth,
                            &device_type);
            }
            ap_dev = to_ap_dev(dev);
            spin_lock_bh(&ap_dev->lock);
            if (rc || ap_dev->unregistered) {
                spin_unlock_bh(&ap_dev->lock);
                if (ap_dev->unregistered)
                    i--;
                device_unregister(dev);
                put_device(dev);
                continue;
            }
            spin_unlock_bh(&ap_dev->lock);
            put_device(dev);
            continue;
        }
        if (rc)
            continue;
        rc = ap_init_queue(qid);
        if (rc)
            continue;
        ap_dev = kzalloc(sizeof(*ap_dev), GFP_KERNEL);
        if (!ap_dev)
            break;
        ap_dev->qid = qid;
        ap_dev->queue_depth = queue_depth;
        ap_dev->unregistered = 1;
        spin_lock_init(&ap_dev->lock);
        INIT_LIST_HEAD(&ap_dev->pendingq);
        INIT_LIST_HEAD(&ap_dev->requestq);
        INIT_LIST_HEAD(&ap_dev->list);
        setup_timer(&ap_dev->timeout, ap_request_timeout,
                (unsigned long) ap_dev);
        switch (device_type) {
        case 0:
            /* device type probing for old cards */
            if (ap_probe_device_type(ap_dev)) {
                kfree(ap_dev);
                continue;
            }
            break;
        default:
            ap_dev->device_type = device_type;
        }

        rc = ap_query_functions(qid, &device_functions);
        if (!rc)
            ap_dev->functions = device_functions;
        else
            ap_dev->functions = 0u;

        ap_dev->device.bus = &ap_bus_type;
        ap_dev->device.parent = ap_root_device;
        if (dev_set_name(&ap_dev->device, "card%02x",
                 AP_QID_DEVICE(ap_dev->qid))) {
            kfree(ap_dev);
            continue;
        }
        ap_dev->device.release = ap_device_release;
        rc = device_register(&ap_dev->device);
        if (rc) {
            put_device(&ap_dev->device);
            continue;
        }
        /* Add device attributes. */
        rc = sysfs_create_group(&ap_dev->device.kobj,
                    &ap_dev_attr_group);
        if (!rc) {
            spin_lock_bh(&ap_dev->lock);
            ap_dev->unregistered = 0;
            spin_unlock_bh(&ap_dev->lock);
        }
        else
            device_unregister(&ap_dev->device);
    }
}

static void
ap_config_timeout(unsigned long ptr)
{
    queue_work(ap_work_queue, &ap_config_work);
    ap_config_timer.expires = jiffies + ap_config_time * HZ;
    add_timer(&ap_config_timer);
}

static inline void __ap_schedule_poll_timer(void)
{
    ktime_t hr_time;

    spin_lock_bh(&ap_poll_timer_lock);
    if (hrtimer_is_queued(&ap_poll_timer) || ap_suspend_flag)
        goto out;
    if (ktime_to_ns(hrtimer_expires_remaining(&ap_poll_timer)) <= 0) {
        hr_time = ktime_set(0, poll_timeout);
        hrtimer_forward_now(&ap_poll_timer, hr_time);
        hrtimer_restart(&ap_poll_timer);
    }
out:
    spin_unlock_bh(&ap_poll_timer_lock);
}

static inline void ap_schedule_poll_timer(void)
{
    if (ap_using_interrupts())
        return;
    __ap_schedule_poll_timer();
}

static int ap_poll_read(struct ap_device *ap_dev, unsigned long *flags)
{
    struct ap_queue_status status;
    struct ap_message *ap_msg;

    if (ap_dev->queue_count <= 0)
        return 0;
    status = __ap_recv(ap_dev->qid, &ap_dev->reply->psmid,
               ap_dev->reply->message, ap_dev->reply->length);
    switch (status.response_code) {
    case AP_RESPONSE_NORMAL:
        atomic_dec(&ap_poll_requests);
        ap_decrease_queue_count(ap_dev);
        list_for_each_entry(ap_msg, &ap_dev->pendingq, list) {
            if (ap_msg->psmid != ap_dev->reply->psmid)
                continue;
            list_del_init(&ap_msg->list);
            ap_dev->pendingq_count--;
            ap_msg->receive(ap_dev, ap_msg, ap_dev->reply);
            break;
        }
        if (ap_dev->queue_count > 0)
            *flags |= 1;
        break;
    case AP_RESPONSE_NO_PENDING_REPLY:
        if (status.queue_empty) {
            /* The card shouldn't forget requests but who knows. */
            atomic_sub(ap_dev->queue_count, &ap_poll_requests);
            ap_dev->queue_count = 0;
            list_splice_init(&ap_dev->pendingq, &ap_dev->requestq);
            ap_dev->requestq_count += ap_dev->pendingq_count;
            ap_dev->pendingq_count = 0;
        } else
            *flags |= 2;
        break;
    default:
        return -ENODEV;
    }
    return 0;
}

static int ap_poll_write(struct ap_device *ap_dev, unsigned long *flags)
{
    struct ap_queue_status status;
    struct ap_message *ap_msg;

    if (ap_dev->requestq_count <= 0 ||
        ap_dev->queue_count >= ap_dev->queue_depth)
        return 0;
    /* Start the next request on the queue. */
    ap_msg = list_entry(ap_dev->requestq.next, struct ap_message, list);
    status = __ap_send(ap_dev->qid, ap_msg->psmid,
               ap_msg->message, ap_msg->length, ap_msg->special);
    switch (status.response_code) {
    case AP_RESPONSE_NORMAL:
        atomic_inc(&ap_poll_requests);
        ap_increase_queue_count(ap_dev);
        list_move_tail(&ap_msg->list, &ap_dev->pendingq);
        ap_dev->requestq_count--;
        ap_dev->pendingq_count++;
        if (ap_dev->queue_count < ap_dev->queue_depth &&
            ap_dev->requestq_count > 0)
            *flags |= 1;
        *flags |= 2;
        break;
    case AP_RESPONSE_RESET_IN_PROGRESS:
        __ap_schedule_poll_timer();
    case AP_RESPONSE_Q_FULL:
        *flags |= 2;
        break;
    case AP_RESPONSE_MESSAGE_TOO_BIG:
    case AP_RESPONSE_REQ_FAC_NOT_INST:
        return -EINVAL;
    default:
        return -ENODEV;
    }
    return 0;
}

static inline int ap_poll_queue(struct ap_device *ap_dev, unsigned long *flags)
{
    int rc;

    rc = ap_poll_read(ap_dev, flags);
    if (rc)
        return rc;
    return ap_poll_write(ap_dev, flags);
}

static int __ap_queue_message(struct ap_device *ap_dev, struct ap_message *ap_msg)
{
    struct ap_queue_status status;

    if (list_empty(&ap_dev->requestq) &&
        ap_dev->queue_count < ap_dev->queue_depth) {
        status = __ap_send(ap_dev->qid, ap_msg->psmid,
                   ap_msg->message, ap_msg->length,
                   ap_msg->special);
        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
            list_add_tail(&ap_msg->list, &ap_dev->pendingq);
            atomic_inc(&ap_poll_requests);
            ap_dev->pendingq_count++;
            ap_increase_queue_count(ap_dev);
            ap_dev->total_request_count++;
            break;
        case AP_RESPONSE_Q_FULL:
        case AP_RESPONSE_RESET_IN_PROGRESS:
            list_add_tail(&ap_msg->list, &ap_dev->requestq);
            ap_dev->requestq_count++;
            ap_dev->total_request_count++;
            return -EBUSY;
        case AP_RESPONSE_REQ_FAC_NOT_INST:
        case AP_RESPONSE_MESSAGE_TOO_BIG:
            ap_msg->receive(ap_dev, ap_msg, ERR_PTR(-EINVAL));
            return -EINVAL;
        default:    /* Device is gone. */
            ap_msg->receive(ap_dev, ap_msg, ERR_PTR(-ENODEV));
            return -ENODEV;
        }
    } else {
        list_add_tail(&ap_msg->list, &ap_dev->requestq);
        ap_dev->requestq_count++;
        ap_dev->total_request_count++;
        return -EBUSY;
    }
    ap_schedule_poll_timer();
    return 0;
}

void ap_queue_message(struct ap_device *ap_dev, struct ap_message *ap_msg)
{
    unsigned long flags;
    int rc;

    /* For asynchronous message handling a valid receive-callback
     * is required. */
    BUG_ON(!ap_msg->receive);

    spin_lock_bh(&ap_dev->lock);
    if (!ap_dev->unregistered) {
        /* Make room on the queue by polling for finished requests. */
        rc = ap_poll_queue(ap_dev, &flags);
        if (!rc)
            rc = __ap_queue_message(ap_dev, ap_msg);
        if (!rc)
            wake_up(&ap_poll_wait);
        if (rc == -ENODEV)
            ap_dev->unregistered = 1;
    } else {
        ap_msg->receive(ap_dev, ap_msg, ERR_PTR(-ENODEV));
        rc = -ENODEV;
    }
    spin_unlock_bh(&ap_dev->lock);
    if (rc == -ENODEV)
        device_unregister(&ap_dev->device);
}
EXPORT_SYMBOL(ap_queue_message);

void ap_cancel_message(struct ap_device *ap_dev, struct ap_message *ap_msg)
{
    struct ap_message *tmp;

    spin_lock_bh(&ap_dev->lock);
    if (!list_empty(&ap_msg->list)) {
        list_for_each_entry(tmp, &ap_dev->pendingq, list)
            if (tmp->psmid == ap_msg->psmid) {
                ap_dev->pendingq_count--;
                goto found;
            }
        ap_dev->requestq_count--;
    found:
        list_del_init(&ap_msg->list);
    }
    spin_unlock_bh(&ap_dev->lock);
}
EXPORT_SYMBOL(ap_cancel_message);

static enum hrtimer_restart ap_poll_timeout(struct hrtimer *unused)
{
    tasklet_schedule(&ap_tasklet);
    return HRTIMER_NORESTART;
}

static void ap_reset(struct ap_device *ap_dev)
{
    int rc;

    ap_dev->reset = AP_RESET_IGNORE;
    atomic_sub(ap_dev->queue_count, &ap_poll_requests);
    ap_dev->queue_count = 0;
    list_splice_init(&ap_dev->pendingq, &ap_dev->requestq);
    ap_dev->requestq_count += ap_dev->pendingq_count;
    ap_dev->pendingq_count = 0;
    rc = ap_init_queue(ap_dev->qid);
    if (rc == -ENODEV)
        ap_dev->unregistered = 1;
    else
        __ap_schedule_poll_timer();
}

static int __ap_poll_device(struct ap_device *ap_dev, unsigned long *flags)
{
    if (!ap_dev->unregistered) {
        if (ap_poll_queue(ap_dev, flags))
            ap_dev->unregistered = 1;
        if (ap_dev->reset == AP_RESET_DO)
            ap_reset(ap_dev);
    }
    return 0;
}

static void ap_poll_all(unsigned long dummy)
{
    unsigned long flags;
    struct ap_device *ap_dev;

    /* 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((u8 *)ap_interrupt_indicator, 0);
    do {
        flags = 0;
        spin_lock(&ap_device_list_lock);
        list_for_each_entry(ap_dev, &ap_device_list, list) {
            spin_lock(&ap_dev->lock);
            __ap_poll_device(ap_dev, &flags);
            spin_unlock(&ap_dev->lock);
        }
        spin_unlock(&ap_device_list_lock);
    } while (flags & 1);
    if (flags & 2)
        ap_schedule_poll_timer();
}

static int ap_poll_thread(void *data)
{
    DECLARE_WAITQUEUE(wait, current);
    unsigned long flags;
    int requests;
    struct ap_device *ap_dev;

    set_user_nice(current, 19);
    while (1) {
        if (ap_suspend_flag)
            return 0;
        if (need_resched()) {
            schedule();
            continue;
        }
        add_wait_queue(&ap_poll_wait, &wait);
        set_current_state(TASK_INTERRUPTIBLE);
        if (kthread_should_stop())
            break;
        requests = atomic_read(&ap_poll_requests);
        if (requests <= 0)
            schedule();
        set_current_state(TASK_RUNNING);
        remove_wait_queue(&ap_poll_wait, &wait);

        flags = 0;
        spin_lock_bh(&ap_device_list_lock);
        list_for_each_entry(ap_dev, &ap_device_list, list) {
            spin_lock(&ap_dev->lock);
            __ap_poll_device(ap_dev, &flags);
            spin_unlock(&ap_dev->lock);
        }
        spin_unlock_bh(&ap_device_list_lock);
    }
    set_current_state(TASK_RUNNING);
    remove_wait_queue(&ap_poll_wait, &wait);
    return 0;
}

static int ap_poll_thread_start(void)
{
    int rc;

    if (ap_using_interrupts() || ap_suspend_flag)
        return 0;
    mutex_lock(&ap_poll_thread_mutex);
    if (!ap_poll_kthread) {
        ap_poll_kthread = kthread_run(ap_poll_thread, NULL, "appoll");
        rc = IS_ERR(ap_poll_kthread) ? PTR_ERR(ap_poll_kthread) : 0;
        if (rc)
            ap_poll_kthread = NULL;
    }
    else
        rc = 0;
    mutex_unlock(&ap_poll_thread_mutex);
    return rc;
}

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

static void ap_request_timeout(unsigned long data)
{
    struct ap_device *ap_dev = (struct ap_device *) data;

    if (ap_dev->reset == AP_RESET_ARMED) {
        ap_dev->reset = AP_RESET_DO;

        if (ap_using_interrupts())
            tasklet_schedule(&ap_tasklet);
    }
}

static void ap_reset_domain(void)
{
    int i;

    if (ap_domain_index != -1)
        for (i = 0; i < AP_DEVICES; i++)
            ap_reset_queue(AP_MKQID(i, ap_domain_index));
}

static void ap_reset_all(void)
{
    int i, j;

    for (i = 0; i < AP_DOMAINS; i++)
        for (j = 0; j < AP_DEVICES; j++)
            ap_reset_queue(AP_MKQID(j, i));
}

static struct reset_call ap_reset_call = {
    .fn = ap_reset_all,
};

int __init ap_module_init(void)
{
    int rc, i;

    if (ap_domain_index < -1 || ap_domain_index >= AP_DOMAINS) {
        pr_warning("%d is not a valid cryptographic domain\n",
               ap_domain_index);
        return -EINVAL;
    }
    /* In resume callback we need to know if the user had set the domain.
     * If so, we can not just reset it.
     */
    if (ap_domain_index >= 0)
        user_set_domain = 1;

    if (ap_instructions_available() != 0) {
        pr_warning("The hardware system does not support "
               "AP instructions\n");
        return -ENODEV;
    }
    if (ap_interrupts_available()) {
        isc_register(AP_ISC);
        ap_interrupt_indicator = s390_register_adapter_interrupt(
            &ap_interrupt_handler, NULL, AP_ISC);
        if (IS_ERR(ap_interrupt_indicator)) {
            ap_interrupt_indicator = NULL;
            isc_unregister(AP_ISC);
        }
    }

    register_reset_call(&ap_reset_call);

    /* 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 = IS_ERR(ap_root_device) ? PTR_ERR(ap_root_device) : 0;
    if (rc)
        goto out_bus;

    ap_work_queue = create_singlethread_workqueue("kapwork");
    if (!ap_work_queue) {
        rc = -ENOMEM;
        goto out_root;
    }

    ap_query_configuration();
    if (ap_select_domain() == 0)
        ap_scan_bus(NULL);

    /* Setup the AP bus rescan timer. */
    init_timer(&ap_config_timer);
    ap_config_timer.function = ap_config_timeout;
    ap_config_timer.data = 0;
    ap_config_timer.expires = jiffies + ap_config_time * HZ;
    add_timer(&ap_config_timer);

    /* 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;
    }

    return 0;

out_work:
    del_timer_sync(&ap_config_timer);
    hrtimer_cancel(&ap_poll_timer);
    destroy_workqueue(ap_work_queue);
out_root:
    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:
    unregister_reset_call(&ap_reset_call);
    if (ap_using_interrupts()) {
        s390_unregister_adapter_interrupt(ap_interrupt_indicator, AP_ISC);
        isc_unregister(AP_ISC);
    }
    return rc;
}

static int __ap_match_all(struct device *dev, void *data)
{
    return 1;
}

void ap_module_exit(void)
{
    int i;
    struct device *dev;

    ap_reset_domain();
    ap_poll_thread_stop();
    del_timer_sync(&ap_config_timer);
    hrtimer_cancel(&ap_poll_timer);
    destroy_workqueue(ap_work_queue);
    tasklet_kill(&ap_tasklet);
    root_device_unregister(ap_root_device);
    while ((dev = bus_find_device(&ap_bus_type, NULL, NULL,
            __ap_match_all)))
    {
        device_unregister(dev);
        put_device(dev);
    }
    for (i = 0; ap_bus_attrs[i]; i++)
        bus_remove_file(&ap_bus_type, ap_bus_attrs[i]);
    bus_unregister(&ap_bus_type);
    unregister_reset_call(&ap_reset_call);
    if (ap_using_interrupts()) {
        s390_unregister_adapter_interrupt(ap_interrupt_indicator, AP_ISC);
        isc_unregister(AP_ISC);
    }
}

module_init(ap_module_init);
module_exit(ap_module_exit);