/*
 * 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, pm_message_t state)
{
	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 int ap_dev_resume(struct device *dev)
{
	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 struct bus_type ap_bus_type = {
	.name = "ap",
	.match = &ap_bus_match,
	.uevent = &ap_uevent,
	.suspend = ap_dev_suspend,
	.resume = ap_dev_resume,
};

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);