Merge tag 'devicetree-for-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git...

[mirror_ubuntu-artful-kernel.git] / drivers / s390 / crypto / ap_bus.c

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

#include "ap_bus.h"

/*
 * Module description.
 */
MODULE_AUTHOR("IBM Corporation");
MODULE_DESCRIPTION("Adjunct Processor Bus driver, " \
                   "Copyright IBM Corp. 2006, 2012");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CRYPTO("z90crypt");

/*
 * Module parameter
 */
int ap_domain_index = -1;       /* Adjunct Processor Domain Index */
module_param_named(domain, ap_domain_index, int, S_IRUSR|S_IRGRP);
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, S_IRUSR|S_IRGRP);
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);
static bool initialised;

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

/*
 * Tasklet & timer for AP request polling and interrupts
 */
static void ap_tasklet_fn(unsigned long);
static DECLARE_TASKLET(ap_tasklet, ap_tasklet_fn, 0);
static 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 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;
/* Maximum domain id */
static int ap_max_domain_id;
/* 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;

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

static int ap_airq_flag;

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

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

/**
 * ap_intructions_available() - Test if AP instructions are available.
 *
 * Returns 0 if the AP instructions are installed.
 */
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;
}

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

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

static inline struct ap_queue_status
__pqap_tapq(ap_qid_t qid, unsigned long *info)
{
        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");
        *info = reg2;
        return reg1;
}

/**
 * ap_test_queue(): Test adjunct processor queue.
 * @qid: The AP queue number
 * @info: Pointer to queue descriptor
 *
 * Returns AP queue status structure.
 */
static inline struct ap_queue_status
ap_test_queue(ap_qid_t qid, unsigned long *info)
{
        struct ap_queue_status aqs;
        unsigned long _info;

        if (test_facility(15))
                qid |= 1UL << 23;               /* set APFT T bit*/
        aqs = __pqap_tapq(qid, &_info);
        if (info)
                *info = _info;
        return aqs;
}

/**
 * ap_reset_queue(): Reset adjunct processor queue.
 * @qid: The AP queue number
 *
 * Returns AP queue status structure.
 */
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;
}

/**
 * ap_queue_interruption_control(): Enable interruption for a specific AP.
 * @qid: The AP queue number
 * @ind: The notification indicator byte
 *
 * Returns AP queue status.
 */
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;
}

/**
 * ap_query_configuration(): Get AP configuration data
 *
 * Returns 0 on success, or -EOPNOTSUPP.
 */
static inline int __ap_query_configuration(void)
{
        register unsigned long reg0 asm ("0") = 0x04000000UL;
        register unsigned long reg1 asm ("1") = -EINVAL;
        register void *reg2 asm ("2") = (void *) ap_configuration;

        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;
}

static inline int ap_query_configuration(void)
{
        if (!ap_configuration)
                return -EOPNOTSUPP;
        return __ap_query_configuration();
}

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

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

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

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

/**
 * ap_queue_enable_interruption(): Enable interruption on an AP.
 * @qid: The AP queue number
 * @ind: the notification indicator byte
 *
 * Enables interruption on AP queue via ap_queue_interruption_control(). Based
 * on the return value it waits a while and tests the AP queue if interrupts
 * have been switched on using ap_test_queue().
 */
static int ap_queue_enable_interruption(struct ap_device *ap_dev, void *ind)
{
        struct ap_queue_status status;

        status = ap_queue_interruption_control(ap_dev->qid, ind);
        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
        case AP_RESPONSE_OTHERWISE_CHANGED:
                return 0;
        case AP_RESPONSE_Q_NOT_AVAIL:
        case AP_RESPONSE_DECONFIGURED:
        case AP_RESPONSE_CHECKSTOPPED:
        case AP_RESPONSE_INVALID_ADDRESS:
                pr_err("Registering adapter interrupts for AP %d failed\n",
                       AP_QID_DEVICE(ap_dev->qid));
                return -EOPNOTSUPP;
        case AP_RESPONSE_RESET_IN_PROGRESS:
        case AP_RESPONSE_BUSY:
        default:
                return -EBUSY;
        }
}

static inline struct ap_queue_status
__nqap(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 | 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") = psmid & 0xffffffff;

        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;
}

/**
 * __ap_send(): Send message to adjunct processor queue.
 * @qid: The AP queue number
 * @psmid: The program supplied message identifier
 * @msg: The message text
 * @length: The message length
 * @special: Special Bit
 *
 * Returns AP queue status structure.
 * Condition code 1 on NQAP can't happen because the L bit is 1.
 * Condition code 2 on NQAP also means the send is incomplete,
 * because a segment boundary was reached. The NQAP is repeated.
 */
static inline struct ap_queue_status
__ap_send(ap_qid_t qid, unsigned long long psmid, void *msg, size_t length,
          unsigned int special)
{
        if (special == 1)
                qid |= 0x400000UL;
        return __nqap(qid, psmid, msg, length);
}

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);

/**
 * __ap_recv(): Receive message from adjunct processor queue.
 * @qid: The AP queue number
 * @psmid: Pointer to program supplied message identifier
 * @msg: The message text
 * @length: The message length
 *
 * Returns AP queue status structure.
 * Condition code 1 on DQAP means the receive has taken place
 * but only partially.  The response is incomplete, hence the
 * DQAP is repeated.
 * Condition code 2 on DQAP also means the receive is incomplete,
 * this time because a segment boundary was reached. Again, the
 * DQAP is repeated.
 * Note that gpr2 is used by the DQAP instruction to keep track of
 * any 'residual' length, in case the instruction gets interrupted.
 * Hence it gets zeroed before the instruction.
 */
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;

        if (msg == NULL)
                return -EINVAL;
        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);

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

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

        status = ap_test_queue(qid, &info);
        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
                *queue_depth = (int)(info & 0xff);
                *device_type = (int)((info >> 24) & 0xff);
                *facilities = (unsigned int)(info >> 32);
                /* Update maximum domain id */
                nd = (info >> 16) & 0xff;
                if ((info & (1UL << 57)) && nd > 0)
                        ap_max_domain_id = nd;
                return 0;
        case AP_RESPONSE_Q_NOT_AVAIL:
        case AP_RESPONSE_DECONFIGURED:
        case AP_RESPONSE_CHECKSTOPPED:
        case AP_RESPONSE_INVALID_ADDRESS:
                return -ENODEV;
        case AP_RESPONSE_RESET_IN_PROGRESS:
        case AP_RESPONSE_OTHERWISE_CHANGED:
        case AP_RESPONSE_BUSY:
                return -EBUSY;
        default:
                BUG();
        }
}

/* State machine definitions and helpers */

static void ap_sm_wait(enum ap_wait wait)
{
        ktime_t hr_time;

        switch (wait) {
        case AP_WAIT_AGAIN:
        case AP_WAIT_INTERRUPT:
                if (ap_using_interrupts())
                        break;
                if (ap_poll_kthread) {
                        wake_up(&ap_poll_wait);
                        break;
                }
                /* Fall through */
        case AP_WAIT_TIMEOUT:
                spin_lock_bh(&ap_poll_timer_lock);
                if (!hrtimer_is_queued(&ap_poll_timer)) {
                        hr_time = ktime_set(0, poll_timeout);
                        hrtimer_forward_now(&ap_poll_timer, hr_time);
                        hrtimer_restart(&ap_poll_timer);
                }
                spin_unlock_bh(&ap_poll_timer_lock);
                break;
        case AP_WAIT_NONE:
        default:
                break;
        }
}

static enum ap_wait ap_sm_nop(struct ap_device *ap_dev)
{
        return AP_WAIT_NONE;
}

/**
 * ap_sm_recv(): Receive pending reply messages from an AP device but do
 *      not change the state of the device.
 * @ap_dev: pointer to the AP device
 *
 * Returns AP_WAIT_NONE, AP_WAIT_AGAIN, or AP_WAIT_INTERRUPT
 */
static struct ap_queue_status ap_sm_recv(struct ap_device *ap_dev)
{
        struct ap_queue_status status;
        struct ap_message *ap_msg;

        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_dev->queue_count--;
                if (ap_dev->queue_count > 0)
                        mod_timer(&ap_dev->timeout,
                                  jiffies + ap_dev->drv->request_timeout);
                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;
                }
        case AP_RESPONSE_NO_PENDING_REPLY:
                if (!status.queue_empty || ap_dev->queue_count <= 0)
                        break;
                /* 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;
                break;
        default:
                break;
        }
        return status;
}

/**
 * ap_sm_read(): Receive pending reply messages from an AP device.
 * @ap_dev: pointer to the AP device
 *
 * Returns AP_WAIT_NONE, AP_WAIT_AGAIN, or AP_WAIT_INTERRUPT
 */
static enum ap_wait ap_sm_read(struct ap_device *ap_dev)
{
        struct ap_queue_status status;

        if (!ap_dev->reply)
                return AP_WAIT_NONE;
        status = ap_sm_recv(ap_dev);
        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
                if (ap_dev->queue_count > 0) {
                        ap_dev->state = AP_STATE_WORKING;
                        return AP_WAIT_AGAIN;
                }
                ap_dev->state = AP_STATE_IDLE;
                return AP_WAIT_NONE;
        case AP_RESPONSE_NO_PENDING_REPLY:
                if (ap_dev->queue_count > 0)
                        return AP_WAIT_INTERRUPT;
                ap_dev->state = AP_STATE_IDLE;
                return AP_WAIT_NONE;
        default:
                ap_dev->state = AP_STATE_BORKED;
                return AP_WAIT_NONE;
        }
}

/**
 * ap_sm_suspend_read(): Receive pending reply messages from an AP device
 * without changing the device state in between. In suspend mode we don't
 * allow sending new requests, therefore just fetch pending replies.
 * @ap_dev: pointer to the AP device
 *
 * Returns AP_WAIT_NONE or AP_WAIT_AGAIN
 */
static enum ap_wait ap_sm_suspend_read(struct ap_device *ap_dev)
{
        struct ap_queue_status status;

        if (!ap_dev->reply)
                return AP_WAIT_NONE;
        status = ap_sm_recv(ap_dev);
        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
                if (ap_dev->queue_count > 0)
                        return AP_WAIT_AGAIN;
                /* fall through */
        default:
                return AP_WAIT_NONE;
        }
}

/**
 * ap_sm_write(): Send messages from the request queue to an AP device.
 * @ap_dev: pointer to the AP device
 *
 * Returns AP_WAIT_NONE, AP_WAIT_AGAIN, or AP_WAIT_INTERRUPT
 */
static enum ap_wait ap_sm_write(struct ap_device *ap_dev)
{
        struct ap_queue_status status;
        struct ap_message *ap_msg;

        if (ap_dev->requestq_count <= 0)
                return AP_WAIT_NONE;
        /* 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_dev->queue_count++;
                if (ap_dev->queue_count == 1)
                        mod_timer(&ap_dev->timeout,
                                  jiffies + ap_dev->drv->request_timeout);
                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->state = AP_STATE_WORKING;
                        return AP_WAIT_AGAIN;
                }
                /* fall through */
        case AP_RESPONSE_Q_FULL:
                ap_dev->state = AP_STATE_QUEUE_FULL;
                return AP_WAIT_INTERRUPT;
        case AP_RESPONSE_RESET_IN_PROGRESS:
                ap_dev->state = AP_STATE_RESET_WAIT;
                return AP_WAIT_TIMEOUT;
        case AP_RESPONSE_MESSAGE_TOO_BIG:
        case AP_RESPONSE_REQ_FAC_NOT_INST:
                list_del_init(&ap_msg->list);
                ap_dev->requestq_count--;
                ap_msg->rc = -EINVAL;
                ap_msg->receive(ap_dev, ap_msg, NULL);
                return AP_WAIT_AGAIN;
        default:
                ap_dev->state = AP_STATE_BORKED;
                return AP_WAIT_NONE;
        }
}

/**
 * ap_sm_read_write(): Send and receive messages to/from an AP device.
 * @ap_dev: pointer to the AP device
 *
 * Returns AP_WAIT_NONE, AP_WAIT_AGAIN, or AP_WAIT_INTERRUPT
 */
static enum ap_wait ap_sm_read_write(struct ap_device *ap_dev)
{
        return min(ap_sm_read(ap_dev), ap_sm_write(ap_dev));
}

/**
 * ap_sm_reset(): Reset an AP queue.
 * @qid: The AP queue number
 *
 * Submit the Reset command to an AP queue.
 */
static enum ap_wait ap_sm_reset(struct ap_device *ap_dev)
{
        struct ap_queue_status status;

        status = ap_reset_queue(ap_dev->qid);
        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
        case AP_RESPONSE_RESET_IN_PROGRESS:
                ap_dev->state = AP_STATE_RESET_WAIT;
                ap_dev->interrupt = AP_INTR_DISABLED;
                return AP_WAIT_TIMEOUT;
        case AP_RESPONSE_BUSY:
                return AP_WAIT_TIMEOUT;
        case AP_RESPONSE_Q_NOT_AVAIL:
        case AP_RESPONSE_DECONFIGURED:
        case AP_RESPONSE_CHECKSTOPPED:
        default:
                ap_dev->state = AP_STATE_BORKED;
                return AP_WAIT_NONE;
        }
}

/**
 * ap_sm_reset_wait(): Test queue for completion of the reset operation
 * @ap_dev: pointer to the AP device
 *
 * Returns AP_POLL_IMMEDIATELY, AP_POLL_AFTER_TIMEROUT or 0.
 */
static enum ap_wait ap_sm_reset_wait(struct ap_device *ap_dev)
{
        struct ap_queue_status status;
        unsigned long info;

        if (ap_dev->queue_count > 0 && ap_dev->reply)
                /* Try to read a completed message and get the status */
                status = ap_sm_recv(ap_dev);
        else
                /* Get the status with TAPQ */
                status = ap_test_queue(ap_dev->qid, &info);

        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
                if (ap_using_interrupts() &&
                    ap_queue_enable_interruption(ap_dev,
                                                 ap_airq.lsi_ptr) == 0)
                        ap_dev->state = AP_STATE_SETIRQ_WAIT;
                else
                        ap_dev->state = (ap_dev->queue_count > 0) ?
                                AP_STATE_WORKING : AP_STATE_IDLE;
                return AP_WAIT_AGAIN;
        case AP_RESPONSE_BUSY:
        case AP_RESPONSE_RESET_IN_PROGRESS:
                return AP_WAIT_TIMEOUT;
        case AP_RESPONSE_Q_NOT_AVAIL:
        case AP_RESPONSE_DECONFIGURED:
        case AP_RESPONSE_CHECKSTOPPED:
        default:
                ap_dev->state = AP_STATE_BORKED;
                return AP_WAIT_NONE;
        }
}

/**
 * ap_sm_setirq_wait(): Test queue for completion of the irq enablement
 * @ap_dev: pointer to the AP device
 *
 * Returns AP_POLL_IMMEDIATELY, AP_POLL_AFTER_TIMEROUT or 0.
 */
static enum ap_wait ap_sm_setirq_wait(struct ap_device *ap_dev)
{
        struct ap_queue_status status;
        unsigned long info;

        if (ap_dev->queue_count > 0 && ap_dev->reply)
                /* Try to read a completed message and get the status */
                status = ap_sm_recv(ap_dev);
        else
                /* Get the status with TAPQ */
                status = ap_test_queue(ap_dev->qid, &info);

        if (status.int_enabled == 1) {
                /* Irqs are now enabled */
                ap_dev->interrupt = AP_INTR_ENABLED;
                ap_dev->state = (ap_dev->queue_count > 0) ?
                        AP_STATE_WORKING : AP_STATE_IDLE;
        }

        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
                if (ap_dev->queue_count > 0)
                        return AP_WAIT_AGAIN;
                /* fallthrough */
        case AP_RESPONSE_NO_PENDING_REPLY:
                return AP_WAIT_TIMEOUT;
        default:
                ap_dev->state = AP_STATE_BORKED;
                return AP_WAIT_NONE;
        }
}

/*
 * AP state machine jump table
 */
static ap_func_t *ap_jumptable[NR_AP_STATES][NR_AP_EVENTS] = {
        [AP_STATE_RESET_START] = {
                [AP_EVENT_POLL] = ap_sm_reset,
                [AP_EVENT_TIMEOUT] = ap_sm_nop,
        },
        [AP_STATE_RESET_WAIT] = {
                [AP_EVENT_POLL] = ap_sm_reset_wait,
                [AP_EVENT_TIMEOUT] = ap_sm_nop,
        },
        [AP_STATE_SETIRQ_WAIT] = {
                [AP_EVENT_POLL] = ap_sm_setirq_wait,
                [AP_EVENT_TIMEOUT] = ap_sm_nop,
        },
        [AP_STATE_IDLE] = {
                [AP_EVENT_POLL] = ap_sm_write,
                [AP_EVENT_TIMEOUT] = ap_sm_nop,
        },
        [AP_STATE_WORKING] = {
                [AP_EVENT_POLL] = ap_sm_read_write,
                [AP_EVENT_TIMEOUT] = ap_sm_reset,
        },
        [AP_STATE_QUEUE_FULL] = {
                [AP_EVENT_POLL] = ap_sm_read,
                [AP_EVENT_TIMEOUT] = ap_sm_reset,
        },
        [AP_STATE_SUSPEND_WAIT] = {
                [AP_EVENT_POLL] = ap_sm_suspend_read,
                [AP_EVENT_TIMEOUT] = ap_sm_nop,
        },
        [AP_STATE_BORKED] = {
                [AP_EVENT_POLL] = ap_sm_nop,
                [AP_EVENT_TIMEOUT] = ap_sm_nop,
        },
};

static inline enum ap_wait ap_sm_event(struct ap_device *ap_dev,
                                       enum ap_event event)
{
        return ap_jumptable[ap_dev->state][event](ap_dev);
}

static inline enum ap_wait ap_sm_event_loop(struct ap_device *ap_dev,
                                            enum ap_event event)
{
        enum ap_wait wait;

        while ((wait = ap_sm_event(ap_dev, event)) == AP_WAIT_AGAIN)
                ;
        return wait;
}

/**
 * ap_request_timeout(): Handling of request timeouts
 * @data: Holds the AP device.
 *
 * Handles request timeouts.
 */
static void ap_request_timeout(unsigned long data)
{
        struct ap_device *ap_dev = (struct ap_device *) data;

        if (ap_suspend_flag)
                return;
        spin_lock_bh(&ap_dev->lock);
        ap_sm_wait(ap_sm_event(ap_dev, AP_EVENT_TIMEOUT));
        spin_unlock_bh(&ap_dev->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)
{
        if (!ap_suspend_flag)
                tasklet_schedule(&ap_tasklet);
        return HRTIMER_NORESTART;
}

/**
 * ap_interrupt_handler() - Schedule ap_tasklet on interrupt
 * @airq: pointer to adapter interrupt descriptor
 */
static void ap_interrupt_handler(struct airq_struct *airq)
{
        inc_irq_stat(IRQIO_APB);
        if (!ap_suspend_flag)
                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)
{
        struct ap_device *ap_dev;
        enum ap_wait wait = AP_WAIT_NONE;

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

        spin_lock(&ap_device_list_lock);
        list_for_each_entry(ap_dev, &ap_device_list, list) {
                spin_lock_bh(&ap_dev->lock);
                wait = min(wait, ap_sm_event_loop(ap_dev, AP_EVENT_POLL));
                spin_unlock_bh(&ap_dev->lock);
        }
        spin_unlock(&ap_device_list_lock);
        ap_sm_wait(wait);
}

/**
 * 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_suspend_flag ||
                    atomic_read(&ap_poll_requests) <= 0) {
                        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);
        } while (!kthread_should_stop());
        return 0;
}

static int ap_poll_thread_start(void)
{
        int rc;

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

/**
 * ap_queue_message(): Queue a request to an AP device.
 * @ap_dev: The AP device to queue the message to
 * @ap_msg: The message that is to be added
 */
void ap_queue_message(struct ap_device *ap_dev, struct ap_message *ap_msg)
{
        /* For asynchronous message handling a valid receive-callback
         * is required. */
        BUG_ON(!ap_msg->receive);

        spin_lock_bh(&ap_dev->lock);
        /* Queue the message. */
        list_add_tail(&ap_msg->list, &ap_dev->requestq);
        ap_dev->requestq_count++;
        ap_dev->total_request_count++;
        /* Send/receive as many request from the queue as possible. */
        ap_sm_wait(ap_sm_event_loop(ap_dev, AP_EVENT_POLL));
        spin_unlock_bh(&ap_dev->lock);
}
EXPORT_SYMBOL(ap_queue_message);

/**
 * ap_cancel_message(): Cancel a crypto request.
 * @ap_dev: The AP device that has the message queued
 * @ap_msg: The message that is to be removed
 *
 * Cancel a crypto request. This is done by removing the request
 * from the device pending or request queue. Note that the
 * request stays on the AP queue. When it finishes the message
 * reply will be discarded because the psmid can't be found.
 */
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);

/*
 * 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_raw_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->raw_hwtype);
}

static DEVICE_ATTR(raw_hwtype, 0444, ap_raw_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_reset_show(struct device *dev,
                                      struct device_attribute *attr, char *buf)
{
        struct ap_device *ap_dev = to_ap_dev(dev);
        int rc = 0;

        spin_lock_bh(&ap_dev->lock);
        switch (ap_dev->state) {
        case AP_STATE_RESET_START:
        case AP_STATE_RESET_WAIT:
                rc = snprintf(buf, PAGE_SIZE, "Reset in progress.\n");
                break;
        case AP_STATE_WORKING:
        case AP_STATE_QUEUE_FULL:
                rc = snprintf(buf, PAGE_SIZE, "Reset Timer armed.\n");
                break;
        default:
                rc = snprintf(buf, PAGE_SIZE, "No Reset Timer set.\n");
        }
        spin_unlock_bh(&ap_dev->lock);
        return rc;
}

static DEVICE_ATTR(reset, 0444, ap_reset_show, NULL);

static ssize_t ap_interrupt_show(struct device *dev,
                                      struct device_attribute *attr, char *buf)
{
        struct ap_device *ap_dev = to_ap_dev(dev);
        int rc = 0;

        spin_lock_bh(&ap_dev->lock);
        if (ap_dev->state == AP_STATE_SETIRQ_WAIT)
                rc = snprintf(buf, PAGE_SIZE, "Enable Interrupt pending.\n");
        else if (ap_dev->interrupt == AP_INTR_ENABLED)
                rc = snprintf(buf, PAGE_SIZE, "Interrupts enabled.\n");
        else
                rc = snprintf(buf, PAGE_SIZE, "Interrupts disabled.\n");
        spin_unlock_bh(&ap_dev->lock);
        return rc;
}

static DEVICE_ATTR(interrupt, 0444, ap_interrupt_show, NULL);

static ssize_t ap_modalias_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        return sprintf(buf, "ap:t%02X\n", 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_raw_hwtype.attr,
        &dev_attr_depth.attr,
        &dev_attr_request_count.attr,
        &dev_attr_requestq_count.attr,
        &dev_attr_pendingq_count.attr,
        &dev_attr_reset.attr,
        &dev_attr_interrupt.attr,
        &dev_attr_modalias.attr,
        &dev_attr_ap_functions.attr,
        NULL
};
static struct attribute_group ap_dev_attr_group = {
        .attrs = ap_dev_attrs
};

/**
 * 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_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;
}

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

        if (!ap_dev)
                return -ENODEV;

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

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

        return retval;
}

static int ap_dev_suspend(struct device *dev)
{
        struct ap_device *ap_dev = to_ap_dev(dev);

        /* Poll on the device until all requests are finished. */
        spin_lock_bh(&ap_dev->lock);
        ap_dev->state = AP_STATE_SUSPEND_WAIT;
        while (ap_sm_event(ap_dev, AP_EVENT_POLL) != AP_WAIT_NONE)
                ;
        ap_dev->state = AP_STATE_BORKED;
        spin_unlock_bh(&ap_dev->lock);
        return 0;
}

static void ap_bus_suspend(void)
{
        ap_suspend_flag = 1;
        /*
         * Disable scanning for devices, thus we do not want to scan
         * for them after removing.
         */
        flush_work(&ap_scan_work);
        tasklet_disable(&ap_tasklet);
}

static int __ap_devices_unregister(struct device *dev, void *dummy)
{
        device_unregister(dev);
        return 0;
}

static void ap_bus_resume(void)
{
        int rc;

        /* Unconditionally remove all AP devices */
        bus_for_each_dev(&ap_bus_type, NULL, NULL, __ap_devices_unregister);
        /* Reset thin interrupt setting */
        if (ap_interrupts_available() && !ap_using_interrupts()) {
                rc = register_adapter_interrupt(&ap_airq);
                ap_airq_flag = (rc == 0);
        }
        if (!ap_interrupts_available() && ap_using_interrupts()) {
                unregister_adapter_interrupt(&ap_airq);
                ap_airq_flag = 0;
        }
        /* Reset domain */
        if (!user_set_domain)
                ap_domain_index = -1;
        /* Get things going again */
        ap_suspend_flag = 0;
        if (ap_airq_flag)
                xchg(ap_airq.lsi_ptr, 0);
        tasklet_enable(&ap_tasklet);
        queue_work(system_long_wq, &ap_scan_work);
}

static int ap_power_event(struct notifier_block *this, unsigned long event,
                          void *ptr)
{
        switch (event) {
        case PM_HIBERNATION_PREPARE:
        case PM_SUSPEND_PREPARE:
                ap_bus_suspend();
                break;
        case PM_POST_HIBERNATION:
        case PM_POST_SUSPEND:
                ap_bus_resume();
                break;
        default:
                break;
        }
        return NOTIFY_DONE;
}
static struct notifier_block ap_power_notifier = {
        .notifier_call = ap_power_event,
};

static SIMPLE_DEV_PM_OPS(ap_bus_pm_ops, ap_dev_suspend, NULL);

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

void ap_device_init_reply(struct ap_device *ap_dev,
                          struct ap_message *reply)
{
        ap_dev->reply = reply;

        spin_lock_bh(&ap_dev->lock);
        ap_sm_wait(ap_sm_event(ap_dev, AP_EVENT_POLL));
        spin_unlock_bh(&ap_dev->lock);
}
EXPORT_SYMBOL(ap_device_init_reply);

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)
                ap_dev->drv = NULL;
        return rc;
}

/**
 * __ap_flush_queue(): Flush requests.
 * @ap_dev: Pointer to the AP device
 *
 * Flush all requests from the request/pending queue of an AP device.
 */
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->rc = -EAGAIN;
                ap_msg->receive(ap_dev, ap_msg, NULL);
        }
        list_for_each_entry_safe(ap_msg, next, &ap_dev->requestq, list) {
                list_del_init(&ap_msg->list);
                ap_dev->requestq_count--;
                ap_msg->rc = -EAGAIN;
                ap_msg->receive(ap_dev, ap_msg, NULL);
        }
}

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;
}

static void ap_device_release(struct device *dev)
{
        kfree(to_ap_dev(dev));
}

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

        if (!initialised)
                return -ENODEV;

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

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

void ap_bus_force_rescan(void)
{
        if (ap_suspend_flag)
                return;
        /* 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);

/*
 * 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_control_domain_mask_show(struct bus_type *bus, char *buf)
{
        if (!ap_configuration)  /* QCI not supported */
                return snprintf(buf, PAGE_SIZE, "not supported\n");
        if (!test_facility(76))
                /* format 0 - 16 bit domain field */
                return snprintf(buf, PAGE_SIZE, "%08x%08x\n",
                                ap_configuration->adm[0],
                                ap_configuration->adm[1]);
        /* format 1 - 256 bit domain field */
        return snprintf(buf, PAGE_SIZE,
                        "0x%08x%08x%08x%08x%08x%08x%08x%08x\n",
                        ap_configuration->adm[0], ap_configuration->adm[1],
                        ap_configuration->adm[2], ap_configuration->adm[3],
                        ap_configuration->adm[4], ap_configuration->adm[5],
                        ap_configuration->adm[6], ap_configuration->adm[7]);
}

static BUS_ATTR(ap_control_domain_mask, 0444,
                ap_control_domain_mask_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;
        mod_timer(&ap_config_timer, jiffies + ap_config_time * HZ);
        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)
                        count = 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);

        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(poll_timeout, 0644, poll_timeout_show, poll_timeout_store);

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

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

static BUS_ATTR(ap_max_domain_id, 0444, ap_max_domain_id_show, NULL);

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

/**
 * ap_select_domain(): Select an AP domain.
 *
 * Pick one of the 16 AP domains.
 */
static int ap_select_domain(void)
{
        int count, max_count, best_domain;
        struct ap_queue_status status;
        int i, j;

        /*
         * We want to use a single domain. Either the one specified with
         * the "domain=" parameter or the domain with the maximum number
         * of devices.
         */
        if (ap_domain_index >= 0)
                /* 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;
                        status = ap_test_queue(AP_MKQID(j, i), NULL);
                        if (status.response_code != AP_RESPONSE_NORMAL)
                                continue;
                        count++;
                }
                if (count > max_count) {
                        max_count = count;
                        best_domain = i;
                }
        }
        if (best_domain >= 0){
                ap_domain_index = best_domain;
                return 0;
        }
        return -ENODEV;
}

/**
 * __ap_scan_bus(): Scan the AP bus.
 * @dev: Pointer to device
 * @data: Pointer to data
 *
 * Scan the AP bus for new devices.
 */
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_scan_bus(struct work_struct *unused)
{
        struct ap_device *ap_dev;
        struct device *dev;
        ap_qid_t qid;
        int queue_depth = 0, device_type = 0;
        unsigned int device_functions = 0;
        int rc, i, borked;

        ap_query_configuration();
        if (ap_select_domain() != 0)
                goto out;

        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);
                rc = ap_query_queue(qid, &queue_depth, &device_type,
                                    &device_functions);
                if (dev) {
                        ap_dev = to_ap_dev(dev);
                        spin_lock_bh(&ap_dev->lock);
                        if (rc == -ENODEV)
                                ap_dev->state = AP_STATE_BORKED;
                        borked = ap_dev->state == AP_STATE_BORKED;
                        spin_unlock_bh(&ap_dev->lock);
                        if (borked)     /* Remove broken device */
                                device_unregister(dev);
                        put_device(dev);
                        if (!borked)
                                continue;
                }
                if (rc)
                        continue;
                ap_dev = kzalloc(sizeof(*ap_dev), GFP_KERNEL);
                if (!ap_dev)
                        break;
                ap_dev->qid = qid;
                ap_dev->state = AP_STATE_RESET_START;
                ap_dev->interrupt = AP_INTR_DISABLED;
                ap_dev->queue_depth = queue_depth;
                ap_dev->raw_hwtype = device_type;
                ap_dev->device_type = device_type;
                ap_dev->functions = device_functions;
                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);

                ap_dev->device.bus = &ap_bus_type;
                ap_dev->device.parent = ap_root_device;
                rc = dev_set_name(&ap_dev->device, "card%02x",
                                  AP_QID_DEVICE(ap_dev->qid));
                if (rc) {
                        kfree(ap_dev);
                        continue;
                }
                /* Add to list of devices */
                spin_lock_bh(&ap_device_list_lock);
                list_add(&ap_dev->list, &ap_device_list);
                spin_unlock_bh(&ap_device_list_lock);
                /* Start with a device reset */
                spin_lock_bh(&ap_dev->lock);
                ap_sm_wait(ap_sm_event(ap_dev, AP_EVENT_POLL));
                spin_unlock_bh(&ap_dev->lock);
                /* Register device */
                ap_dev->device.release = ap_device_release;
                rc = device_register(&ap_dev->device);
                if (rc) {
                        spin_lock_bh(&ap_dev->lock);
                        list_del_init(&ap_dev->list);
                        spin_unlock_bh(&ap_dev->lock);
                        put_device(&ap_dev->device);
                        continue;
                }
                /* Add device attributes. */
                rc = sysfs_create_group(&ap_dev->device.kobj,
                                        &ap_dev_attr_group);
                if (rc) {
                        device_unregister(&ap_dev->device);
                        continue;
                }
        }
out:
        mod_timer(&ap_config_timer, jiffies + ap_config_time * HZ);
}

static void ap_config_timeout(unsigned long ptr)
{
        if (ap_suspend_flag)
                return;
        queue_work(system_long_wq, &ap_scan_work);
}

static void ap_reset_domain(void)
{
        int i;

        if (ap_domain_index == -1 || !ap_test_config_domain(ap_domain_index))
                return;
        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++) {
                if (!ap_test_config_domain(i))
                        continue;
                for (j = 0; j < AP_DEVICES; j++) {
                        if (!ap_test_config_card_id(j))
                                continue;
                        ap_reset_queue(AP_MKQID(j, i));
                }
        }
}

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

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

        if (ap_instructions_available() != 0) {
                pr_warn("The hardware system does not support AP instructions\n");
                return -ENODEV;
        }

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

        if (ap_configuration)
                max_domain_id = ap_max_domain_id ? : (AP_DOMAINS - 1);
        else
                max_domain_id = 15;
        if (ap_domain_index < -1 || ap_domain_index > max_domain_id) {
                pr_warn("%d is not a valid cryptographic domain\n",
                        ap_domain_index);
                rc = -EINVAL;
                goto out_free;
        }
        /* 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_interrupts_available()) {
                rc = register_adapter_interrupt(&ap_airq);
                ap_airq_flag = (rc == 0);
        }

        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 = PTR_RET(ap_root_device);
        if (rc)
                goto out_bus;

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

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

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

        rc = register_pm_notifier(&ap_power_notifier);
        if (rc)
                goto out_pm;

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

        return 0;

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

/**
 * ap_modules_exit(): The module termination code
 *
 * Terminates the module.
 */
void ap_module_exit(void)
{
        int i;

        initialised = false;
        ap_reset_domain();
        ap_poll_thread_stop();
        del_timer_sync(&ap_config_timer);
        hrtimer_cancel(&ap_poll_timer);
        tasklet_kill(&ap_tasklet);
        bus_for_each_dev(&ap_bus_type, NULL, NULL, __ap_devices_unregister);
        for (i = 0; ap_bus_attrs[i]; i++)
                bus_remove_file(&ap_bus_type, ap_bus_attrs[i]);
        unregister_pm_notifier(&ap_power_notifier);
        root_device_unregister(ap_root_device);
        bus_unregister(&ap_bus_type);
        kfree(ap_configuration);
        unregister_reset_call(&ap_reset_call);
        if (ap_using_interrupts())
                unregister_adapter_interrupt(&ap_airq);
}

module_init(ap_module_init);
module_exit(ap_module_exit);