// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright IBM Corp. 2016
 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
 *
 * Adjunct processor bus, queue related code.
 */

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

#include <linux/init.h>
#include <linux/slab.h>
#include <asm/facility.h>

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

static void __ap_flush_queue(struct ap_queue *aq);

/**
 * ap_queue_enable_interruption(): Enable interruption on an AP queue.
 * @qid: The AP queue number
 * @ind: the notification indicator byte
 *
 * Enables interruption on AP queue via ap_aqic(). 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_queue *aq, void *ind)
{
        struct ap_queue_status status;
        struct ap_qirq_ctrl qirqctrl = { 0 };

        qirqctrl.ir = 1;
        qirqctrl.isc = AP_ISC;
        status = ap_aqic(aq->qid, qirqctrl, 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 device %02x.%04x failed\n",
                       AP_QID_CARD(aq->qid),
                       AP_QID_QUEUE(aq->qid));
                return -EOPNOTSUPP;
        case AP_RESPONSE_RESET_IN_PROGRESS:
        case AP_RESPONSE_BUSY:
        default:
                return -EBUSY;
        }
}

/**
 * __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,
          int special)
{
        if (special)
                qid |= 0x400000UL;
        return ap_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);

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_dqap(qid, psmid, msg, length, NULL, NULL);
        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);

/* State machine definitions and helpers */

static enum ap_sm_wait ap_sm_nop(struct ap_queue *aq)
{
        return AP_SM_WAIT_NONE;
}

/**
 * ap_sm_recv(): Receive pending reply messages from an AP queue but do
 *      not change the state of the device.
 * @aq: pointer to the AP queue
 *
 * Returns AP_SM_WAIT_NONE, AP_SM_WAIT_AGAIN, or AP_SM_WAIT_INTERRUPT
 */
static struct ap_queue_status ap_sm_recv(struct ap_queue *aq)
{
        struct ap_queue_status status;
        struct ap_message *ap_msg;
        bool found = false;
        size_t reslen;
        unsigned long resgr0 = 0;
        int parts = 0;

        /*
         * DQAP loop until response code and resgr0 indicate that
         * the msg is totally received. As we use the very same buffer
         * the msg is overwritten with each invocation. That's intended
         * and the receiver of the msg is informed with a msg rc code
         * of EMSGSIZE in such a case.
         */
        do {
                status = ap_dqap(aq->qid, &aq->reply->psmid,
                                 aq->reply->msg, aq->reply->bufsize,
                                 &reslen, &resgr0);
                parts++;
        } while (status.response_code == 0xFF && resgr0 != 0);

        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
                aq->queue_count = max_t(int, 0, aq->queue_count - 1);
                if (aq->queue_count > 0)
                        mod_timer(&aq->timeout,
                                  jiffies + aq->request_timeout);
                list_for_each_entry(ap_msg, &aq->pendingq, list) {
                        if (ap_msg->psmid != aq->reply->psmid)
                                continue;
                        list_del_init(&ap_msg->list);
                        aq->pendingq_count--;
                        if (parts > 1) {
                                ap_msg->rc = -EMSGSIZE;
                                ap_msg->receive(aq, ap_msg, NULL);
                        } else {
                                ap_msg->receive(aq, ap_msg, aq->reply);
                        }
                        found = true;
                        break;
                }
                if (!found) {
                        AP_DBF_WARN("%s unassociated reply psmid=0x%016llx on 0x%02x.%04x\n",
                                    __func__, aq->reply->psmid,
                                    AP_QID_CARD(aq->qid), AP_QID_QUEUE(aq->qid));
                }
                fallthrough;
        case AP_RESPONSE_NO_PENDING_REPLY:
                if (!status.queue_empty || aq->queue_count <= 0)
                        break;
                /* The card shouldn't forget requests but who knows. */
                aq->queue_count = 0;
                list_splice_init(&aq->pendingq, &aq->requestq);
                aq->requestq_count += aq->pendingq_count;
                aq->pendingq_count = 0;
                break;
        default:
                break;
        }
        return status;
}

/**
 * ap_sm_read(): Receive pending reply messages from an AP queue.
 * @aq: pointer to the AP queue
 *
 * Returns AP_SM_WAIT_NONE, AP_SM_WAIT_AGAIN, or AP_SM_WAIT_INTERRUPT
 */
static enum ap_sm_wait ap_sm_read(struct ap_queue *aq)
{
        struct ap_queue_status status;

        if (!aq->reply)
                return AP_SM_WAIT_NONE;
        status = ap_sm_recv(aq);
        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
                if (aq->queue_count > 0) {
                        aq->sm_state = AP_SM_STATE_WORKING;
                        return AP_SM_WAIT_AGAIN;
                }
                aq->sm_state = AP_SM_STATE_IDLE;
                return AP_SM_WAIT_NONE;
        case AP_RESPONSE_NO_PENDING_REPLY:
                if (aq->queue_count > 0)
                        return AP_SM_WAIT_INTERRUPT;
                aq->sm_state = AP_SM_STATE_IDLE;
                return AP_SM_WAIT_NONE;
        default:
                aq->dev_state = AP_DEV_STATE_ERROR;
                aq->last_err_rc = status.response_code;
                AP_DBF_WARN("%s RC 0x%02x on 0x%02x.%04x -> AP_DEV_STATE_ERROR\n",
                            __func__, status.response_code,
                            AP_QID_CARD(aq->qid), AP_QID_QUEUE(aq->qid));
                return AP_SM_WAIT_NONE;
        }
}

/**
 * ap_sm_write(): Send messages from the request queue to an AP queue.
 * @aq: pointer to the AP queue
 *
 * Returns AP_SM_WAIT_NONE, AP_SM_WAIT_AGAIN, or AP_SM_WAIT_INTERRUPT
 */
static enum ap_sm_wait ap_sm_write(struct ap_queue *aq)
{
        struct ap_queue_status status;
        struct ap_message *ap_msg;
        ap_qid_t qid = aq->qid;

        if (aq->requestq_count <= 0)
                return AP_SM_WAIT_NONE;
        /* Start the next request on the queue. */
        ap_msg = list_entry(aq->requestq.next, struct ap_message, list);
#ifdef CONFIG_ZCRYPT_DEBUG
        if (ap_msg->fi.action == AP_FI_ACTION_NQAP_QID_INVAL) {
                AP_DBF_WARN("%s fi cmd 0x%04x: forcing invalid qid 0xFF00\n",
                            __func__, ap_msg->fi.cmd);
                qid = 0xFF00;
        }
#endif
        status = __ap_send(qid, ap_msg->psmid,
                           ap_msg->msg, ap_msg->len,
                           ap_msg->flags & AP_MSG_FLAG_SPECIAL);
        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
                aq->queue_count = max_t(int, 1, aq->queue_count + 1);
                if (aq->queue_count == 1)
                        mod_timer(&aq->timeout, jiffies + aq->request_timeout);
                list_move_tail(&ap_msg->list, &aq->pendingq);
                aq->requestq_count--;
                aq->pendingq_count++;
                if (aq->queue_count < aq->card->queue_depth) {
                        aq->sm_state = AP_SM_STATE_WORKING;
                        return AP_SM_WAIT_AGAIN;
                }
                fallthrough;
        case AP_RESPONSE_Q_FULL:
                aq->sm_state = AP_SM_STATE_QUEUE_FULL;
                return AP_SM_WAIT_INTERRUPT;
        case AP_RESPONSE_RESET_IN_PROGRESS:
                aq->sm_state = AP_SM_STATE_RESET_WAIT;
                return AP_SM_WAIT_TIMEOUT;
        case AP_RESPONSE_INVALID_DOMAIN:
                AP_DBF(DBF_WARN, "AP_RESPONSE_INVALID_DOMAIN on NQAP\n");
                fallthrough;
        case AP_RESPONSE_MESSAGE_TOO_BIG:
        case AP_RESPONSE_REQ_FAC_NOT_INST:
                list_del_init(&ap_msg->list);
                aq->requestq_count--;
                ap_msg->rc = -EINVAL;
                ap_msg->receive(aq, ap_msg, NULL);
                return AP_SM_WAIT_AGAIN;
        default:
                aq->dev_state = AP_DEV_STATE_ERROR;
                aq->last_err_rc = status.response_code;
                AP_DBF_WARN("%s RC 0x%02x on 0x%02x.%04x -> AP_DEV_STATE_ERROR\n",
                            __func__, status.response_code,
                            AP_QID_CARD(aq->qid), AP_QID_QUEUE(aq->qid));
                return AP_SM_WAIT_NONE;
        }
}

/**
 * ap_sm_read_write(): Send and receive messages to/from an AP queue.
 * @aq: pointer to the AP queue
 *
 * Returns AP_SM_WAIT_NONE, AP_SM_WAIT_AGAIN, or AP_SM_WAIT_INTERRUPT
 */
static enum ap_sm_wait ap_sm_read_write(struct ap_queue *aq)
{
        return min(ap_sm_read(aq), ap_sm_write(aq));
}

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

        status = ap_rapq(aq->qid);
        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
        case AP_RESPONSE_RESET_IN_PROGRESS:
                aq->sm_state = AP_SM_STATE_RESET_WAIT;
                aq->interrupt = AP_INTR_DISABLED;
                return AP_SM_WAIT_TIMEOUT;
        default:
                aq->dev_state = AP_DEV_STATE_ERROR;
                aq->last_err_rc = status.response_code;
                AP_DBF_WARN("%s RC 0x%02x on 0x%02x.%04x -> AP_DEV_STATE_ERROR\n",
                            __func__, status.response_code,
                            AP_QID_CARD(aq->qid), AP_QID_QUEUE(aq->qid));
                return AP_SM_WAIT_NONE;
        }
}

/**
 * ap_sm_reset_wait(): Test queue for completion of the reset operation
 * @aq: pointer to the AP queue
 *
 * Returns AP_POLL_IMMEDIATELY, AP_POLL_AFTER_TIMEROUT or 0.
 */
static enum ap_sm_wait ap_sm_reset_wait(struct ap_queue *aq)
{
        struct ap_queue_status status;
        void *lsi_ptr;

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

        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
                lsi_ptr = ap_airq_ptr();
                if (lsi_ptr && ap_queue_enable_interruption(aq, lsi_ptr) == 0)
                        aq->sm_state = AP_SM_STATE_SETIRQ_WAIT;
                else
                        aq->sm_state = (aq->queue_count > 0) ?
                                AP_SM_STATE_WORKING : AP_SM_STATE_IDLE;
                return AP_SM_WAIT_AGAIN;
        case AP_RESPONSE_BUSY:
        case AP_RESPONSE_RESET_IN_PROGRESS:
                return AP_SM_WAIT_TIMEOUT;
        case AP_RESPONSE_Q_NOT_AVAIL:
        case AP_RESPONSE_DECONFIGURED:
        case AP_RESPONSE_CHECKSTOPPED:
        default:
                aq->dev_state = AP_DEV_STATE_ERROR;
                aq->last_err_rc = status.response_code;
                AP_DBF_WARN("%s RC 0x%02x on 0x%02x.%04x -> AP_DEV_STATE_ERROR\n",
                            __func__, status.response_code,
                            AP_QID_CARD(aq->qid), AP_QID_QUEUE(aq->qid));
                return AP_SM_WAIT_NONE;
        }
}

/**
 * ap_sm_setirq_wait(): Test queue for completion of the irq enablement
 * @aq: pointer to the AP queue
 *
 * Returns AP_POLL_IMMEDIATELY, AP_POLL_AFTER_TIMEROUT or 0.
 */
static enum ap_sm_wait ap_sm_setirq_wait(struct ap_queue *aq)
{
        struct ap_queue_status status;

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

        if (status.irq_enabled == 1) {
                /* Irqs are now enabled */
                aq->interrupt = AP_INTR_ENABLED;
                aq->sm_state = (aq->queue_count > 0) ?
                        AP_SM_STATE_WORKING : AP_SM_STATE_IDLE;
        }

        switch (status.response_code) {
        case AP_RESPONSE_NORMAL:
                if (aq->queue_count > 0)
                        return AP_SM_WAIT_AGAIN;
                fallthrough;
        case AP_RESPONSE_NO_PENDING_REPLY:
                return AP_SM_WAIT_TIMEOUT;
        default:
                aq->dev_state = AP_DEV_STATE_ERROR;
                aq->last_err_rc = status.response_code;
                AP_DBF_WARN("%s RC 0x%02x on 0x%02x.%04x -> AP_DEV_STATE_ERROR\n",
                            __func__, status.response_code,
                            AP_QID_CARD(aq->qid), AP_QID_QUEUE(aq->qid));
                return AP_SM_WAIT_NONE;
        }
}

/*
 * AP state machine jump table
 */
static ap_func_t *ap_jumptable[NR_AP_SM_STATES][NR_AP_SM_EVENTS] = {
        [AP_SM_STATE_RESET_START] = {
                [AP_SM_EVENT_POLL] = ap_sm_reset,
                [AP_SM_EVENT_TIMEOUT] = ap_sm_nop,
        },
        [AP_SM_STATE_RESET_WAIT] = {
                [AP_SM_EVENT_POLL] = ap_sm_reset_wait,
                [AP_SM_EVENT_TIMEOUT] = ap_sm_nop,
        },
        [AP_SM_STATE_SETIRQ_WAIT] = {
                [AP_SM_EVENT_POLL] = ap_sm_setirq_wait,
                [AP_SM_EVENT_TIMEOUT] = ap_sm_nop,
        },
        [AP_SM_STATE_IDLE] = {
                [AP_SM_EVENT_POLL] = ap_sm_write,
                [AP_SM_EVENT_TIMEOUT] = ap_sm_nop,
        },
        [AP_SM_STATE_WORKING] = {
                [AP_SM_EVENT_POLL] = ap_sm_read_write,
                [AP_SM_EVENT_TIMEOUT] = ap_sm_reset,
        },
        [AP_SM_STATE_QUEUE_FULL] = {
                [AP_SM_EVENT_POLL] = ap_sm_read,
                [AP_SM_EVENT_TIMEOUT] = ap_sm_reset,
        },
};

enum ap_sm_wait ap_sm_event(struct ap_queue *aq, enum ap_sm_event event)
{
        if (aq->dev_state > AP_DEV_STATE_UNINITIATED)
                return ap_jumptable[aq->sm_state][event](aq);
        else
                return AP_SM_WAIT_NONE;
}

enum ap_sm_wait ap_sm_event_loop(struct ap_queue *aq, enum ap_sm_event event)
{
        enum ap_sm_wait wait;

        while ((wait = ap_sm_event(aq, event)) == AP_SM_WAIT_AGAIN)
                ;
        return wait;
}

/*
 * AP queue related attributes.
 */
static ssize_t request_count_show(struct device *dev,
                                  struct device_attribute *attr,
                                  char *buf)
{
        struct ap_queue *aq = to_ap_queue(dev);
        bool valid = false;
        u64 req_cnt;

        spin_lock_bh(&aq->lock);
        if (aq->dev_state > AP_DEV_STATE_UNINITIATED) {
                req_cnt = aq->total_request_count;
                valid = true;
        }
        spin_unlock_bh(&aq->lock);

        if (valid)
                return scnprintf(buf, PAGE_SIZE, "%llu\n", req_cnt);
        else
                return scnprintf(buf, PAGE_SIZE, "-\n");
}

static ssize_t request_count_store(struct device *dev,
                                   struct device_attribute *attr,
                                   const char *buf, size_t count)
{
        struct ap_queue *aq = to_ap_queue(dev);

        spin_lock_bh(&aq->lock);
        aq->total_request_count = 0;
        spin_unlock_bh(&aq->lock);

        return count;
}

static DEVICE_ATTR_RW(request_count);

static ssize_t requestq_count_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct ap_queue *aq = to_ap_queue(dev);
        unsigned int reqq_cnt = 0;

        spin_lock_bh(&aq->lock);
        if (aq->dev_state > AP_DEV_STATE_UNINITIATED)
                reqq_cnt = aq->requestq_count;
        spin_unlock_bh(&aq->lock);
        return scnprintf(buf, PAGE_SIZE, "%d\n", reqq_cnt);
}

static DEVICE_ATTR_RO(requestq_count);

static ssize_t pendingq_count_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct ap_queue *aq = to_ap_queue(dev);
        unsigned int penq_cnt = 0;

        spin_lock_bh(&aq->lock);
        if (aq->dev_state > AP_DEV_STATE_UNINITIATED)
                penq_cnt = aq->pendingq_count;
        spin_unlock_bh(&aq->lock);
        return scnprintf(buf, PAGE_SIZE, "%d\n", penq_cnt);
}

static DEVICE_ATTR_RO(pendingq_count);

static ssize_t reset_show(struct device *dev,
                          struct device_attribute *attr, char *buf)
{
        struct ap_queue *aq = to_ap_queue(dev);
        int rc = 0;

        spin_lock_bh(&aq->lock);
        switch (aq->sm_state) {
        case AP_SM_STATE_RESET_START:
        case AP_SM_STATE_RESET_WAIT:
                rc = scnprintf(buf, PAGE_SIZE, "Reset in progress.\n");
                break;
        case AP_SM_STATE_WORKING:
        case AP_SM_STATE_QUEUE_FULL:
                rc = scnprintf(buf, PAGE_SIZE, "Reset Timer armed.\n");
                break;
        default:
                rc = scnprintf(buf, PAGE_SIZE, "No Reset Timer set.\n");
        }
        spin_unlock_bh(&aq->lock);
        return rc;
}

static ssize_t reset_store(struct device *dev,
                           struct device_attribute *attr,
                           const char *buf, size_t count)
{
        struct ap_queue *aq = to_ap_queue(dev);

        spin_lock_bh(&aq->lock);
        __ap_flush_queue(aq);
        aq->sm_state = AP_SM_STATE_RESET_START;
        ap_wait(ap_sm_event(aq, AP_SM_EVENT_POLL));
        spin_unlock_bh(&aq->lock);

        AP_DBF(DBF_INFO, "reset queue=%02x.%04x triggered by user\n",
               AP_QID_CARD(aq->qid), AP_QID_QUEUE(aq->qid));

        return count;
}

static DEVICE_ATTR_RW(reset);

static ssize_t interrupt_show(struct device *dev,
                              struct device_attribute *attr, char *buf)
{
        struct ap_queue *aq = to_ap_queue(dev);
        int rc = 0;

        spin_lock_bh(&aq->lock);
        if (aq->sm_state == AP_SM_STATE_SETIRQ_WAIT)
                rc = scnprintf(buf, PAGE_SIZE, "Enable Interrupt pending.\n");
        else if (aq->interrupt == AP_INTR_ENABLED)
                rc = scnprintf(buf, PAGE_SIZE, "Interrupts enabled.\n");
        else
                rc = scnprintf(buf, PAGE_SIZE, "Interrupts disabled.\n");
        spin_unlock_bh(&aq->lock);
        return rc;
}

static DEVICE_ATTR_RO(interrupt);

static ssize_t config_show(struct device *dev,
                             struct device_attribute *attr, char *buf)
{
        struct ap_queue *aq = to_ap_queue(dev);
        int rc;

        spin_lock_bh(&aq->lock);
        rc = scnprintf(buf, PAGE_SIZE, "%d\n", aq->config ? 1 : 0);
        spin_unlock_bh(&aq->lock);
        return rc;
}

static DEVICE_ATTR_RO(config);

#ifdef CONFIG_ZCRYPT_DEBUG
static ssize_t states_show(struct device *dev,
                           struct device_attribute *attr, char *buf)
{
        struct ap_queue *aq = to_ap_queue(dev);
        int rc = 0;

        spin_lock_bh(&aq->lock);
        /* queue device state */
        switch (aq->dev_state) {
        case AP_DEV_STATE_UNINITIATED:
                rc = scnprintf(buf, PAGE_SIZE, "UNINITIATED\n");
                break;
        case AP_DEV_STATE_OPERATING:
                rc = scnprintf(buf, PAGE_SIZE, "OPERATING");
                break;
        case AP_DEV_STATE_SHUTDOWN:
                rc = scnprintf(buf, PAGE_SIZE, "SHUTDOWN");
                break;
        case AP_DEV_STATE_ERROR:
                rc = scnprintf(buf, PAGE_SIZE, "ERROR");
                break;
        default:
                rc = scnprintf(buf, PAGE_SIZE, "UNKNOWN");
        }
        /* state machine state */
        if (aq->dev_state) {
                switch (aq->sm_state) {
                case AP_SM_STATE_RESET_START:
                        rc += scnprintf(buf + rc, PAGE_SIZE - rc,
                                        " [RESET_START]\n");
                        break;
                case AP_SM_STATE_RESET_WAIT:
                        rc += scnprintf(buf + rc, PAGE_SIZE - rc,
                                        " [RESET_WAIT]\n");
                        break;
                case AP_SM_STATE_SETIRQ_WAIT:
                        rc += scnprintf(buf + rc, PAGE_SIZE - rc,
                                        " [SETIRQ_WAIT]\n");
                        break;
                case AP_SM_STATE_IDLE:
                        rc += scnprintf(buf + rc, PAGE_SIZE - rc,
                                        " [IDLE]\n");
                        break;
                case AP_SM_STATE_WORKING:
                        rc += scnprintf(buf + rc, PAGE_SIZE - rc,
                                        " [WORKING]\n");
                        break;
                case AP_SM_STATE_QUEUE_FULL:
                        rc += scnprintf(buf + rc, PAGE_SIZE - rc,
                                        " [FULL]\n");
                        break;
                default:
                        rc += scnprintf(buf + rc, PAGE_SIZE - rc,
                                        " [UNKNOWN]\n");
                }
        }
        spin_unlock_bh(&aq->lock);

        return rc;
}
static DEVICE_ATTR_RO(states);

static ssize_t last_err_rc_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct ap_queue *aq = to_ap_queue(dev);
        int rc;

        spin_lock_bh(&aq->lock);
        rc = aq->last_err_rc;
        spin_unlock_bh(&aq->lock);

        switch (rc) {
        case AP_RESPONSE_NORMAL:
                return scnprintf(buf, PAGE_SIZE, "NORMAL\n");
        case AP_RESPONSE_Q_NOT_AVAIL:
                return scnprintf(buf, PAGE_SIZE, "Q_NOT_AVAIL\n");
        case AP_RESPONSE_RESET_IN_PROGRESS:
                return scnprintf(buf, PAGE_SIZE, "RESET_IN_PROGRESS\n");
        case AP_RESPONSE_DECONFIGURED:
                return scnprintf(buf, PAGE_SIZE, "DECONFIGURED\n");
        case AP_RESPONSE_CHECKSTOPPED:
                return scnprintf(buf, PAGE_SIZE, "CHECKSTOPPED\n");
        case AP_RESPONSE_BUSY:
                return scnprintf(buf, PAGE_SIZE, "BUSY\n");
        case AP_RESPONSE_INVALID_ADDRESS:
                return scnprintf(buf, PAGE_SIZE, "INVALID_ADDRESS\n");
        case AP_RESPONSE_OTHERWISE_CHANGED:
                return scnprintf(buf, PAGE_SIZE, "OTHERWISE_CHANGED\n");
        case AP_RESPONSE_Q_FULL:
                return scnprintf(buf, PAGE_SIZE, "Q_FULL/NO_PENDING_REPLY\n");
        case AP_RESPONSE_INDEX_TOO_BIG:
                return scnprintf(buf, PAGE_SIZE, "INDEX_TOO_BIG\n");
        case AP_RESPONSE_NO_FIRST_PART:
                return scnprintf(buf, PAGE_SIZE, "NO_FIRST_PART\n");
        case AP_RESPONSE_MESSAGE_TOO_BIG:
                return scnprintf(buf, PAGE_SIZE, "MESSAGE_TOO_BIG\n");
        case AP_RESPONSE_REQ_FAC_NOT_INST:
                return scnprintf(buf, PAGE_SIZE, "REQ_FAC_NOT_INST\n");
        default:
                return scnprintf(buf, PAGE_SIZE, "response code %d\n", rc);
        }
}
static DEVICE_ATTR_RO(last_err_rc);
#endif

static struct attribute *ap_queue_dev_attrs[] = {
        &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_config.attr,
#ifdef CONFIG_ZCRYPT_DEBUG
        &dev_attr_states.attr,
        &dev_attr_last_err_rc.attr,
#endif
        NULL
};

static struct attribute_group ap_queue_dev_attr_group = {
        .attrs = ap_queue_dev_attrs
};

static const struct attribute_group *ap_queue_dev_attr_groups[] = {
        &ap_queue_dev_attr_group,
        NULL
};

static struct device_type ap_queue_type = {
        .name = "ap_queue",
        .groups = ap_queue_dev_attr_groups,
};

static void ap_queue_device_release(struct device *dev)
{
        struct ap_queue *aq = to_ap_queue(dev);

        spin_lock_bh(&ap_queues_lock);
        hash_del(&aq->hnode);
        spin_unlock_bh(&ap_queues_lock);

        kfree(aq);
}

struct ap_queue *ap_queue_create(ap_qid_t qid, int device_type)
{
        struct ap_queue *aq;

        aq = kzalloc(sizeof(*aq), GFP_KERNEL);
        if (!aq)
                return NULL;
        aq->ap_dev.device.release = ap_queue_device_release;
        aq->ap_dev.device.type = &ap_queue_type;
        aq->ap_dev.device_type = device_type;
        aq->qid = qid;
        aq->interrupt = AP_INTR_DISABLED;
        spin_lock_init(&aq->lock);
        INIT_LIST_HEAD(&aq->pendingq);
        INIT_LIST_HEAD(&aq->requestq);
        timer_setup(&aq->timeout, ap_request_timeout, 0);

        return aq;
}

void ap_queue_init_reply(struct ap_queue *aq, struct ap_message *reply)
{
        aq->reply = reply;

        spin_lock_bh(&aq->lock);
        ap_wait(ap_sm_event(aq, AP_SM_EVENT_POLL));
        spin_unlock_bh(&aq->lock);
}
EXPORT_SYMBOL(ap_queue_init_reply);

/**
 * ap_queue_message(): Queue a request to an AP device.
 * @aq: The AP device to queue the message to
 * @ap_msg: The message that is to be added
 */
int ap_queue_message(struct ap_queue *aq, struct ap_message *ap_msg)
{
        int rc = 0;

        /* msg needs to have a valid receive-callback */
        BUG_ON(!ap_msg->receive);

        spin_lock_bh(&aq->lock);

        /* only allow to queue new messages if device state is ok */
        if (aq->dev_state == AP_DEV_STATE_OPERATING) {
                list_add_tail(&ap_msg->list, &aq->requestq);
                aq->requestq_count++;
                aq->total_request_count++;
                atomic64_inc(&aq->card->total_request_count);
        } else
                rc = -ENODEV;

        /* Send/receive as many request from the queue as possible. */
        ap_wait(ap_sm_event_loop(aq, AP_SM_EVENT_POLL));

        spin_unlock_bh(&aq->lock);

        return rc;
}
EXPORT_SYMBOL(ap_queue_message);

/**
 * ap_cancel_message(): Cancel a crypto request.
 * @aq: 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_queue *aq, struct ap_message *ap_msg)
{
        struct ap_message *tmp;

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

/**
 * __ap_flush_queue(): Flush requests.
 * @aq: Pointer to the AP queue
 *
 * Flush all requests from the request/pending queue of an AP device.
 */
static void __ap_flush_queue(struct ap_queue *aq)
{
        struct ap_message *ap_msg, *next;

        list_for_each_entry_safe(ap_msg, next, &aq->pendingq, list) {
                list_del_init(&ap_msg->list);
                aq->pendingq_count--;
                ap_msg->rc = -EAGAIN;
                ap_msg->receive(aq, ap_msg, NULL);
        }
        list_for_each_entry_safe(ap_msg, next, &aq->requestq, list) {
                list_del_init(&ap_msg->list);
                aq->requestq_count--;
                ap_msg->rc = -EAGAIN;
                ap_msg->receive(aq, ap_msg, NULL);
        }
        aq->queue_count = 0;
}

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

void ap_queue_prepare_remove(struct ap_queue *aq)
{
        spin_lock_bh(&aq->lock);
        /* flush queue */
        __ap_flush_queue(aq);
        /* move queue device state to SHUTDOWN in progress */
        aq->dev_state = AP_DEV_STATE_SHUTDOWN;
        spin_unlock_bh(&aq->lock);
        del_timer_sync(&aq->timeout);
}

void ap_queue_remove(struct ap_queue *aq)
{
        /*
         * all messages have been flushed and the device state
         * is SHUTDOWN. Now reset with zero which also clears
         * the irq registration and move the device state
         * to the initial value AP_DEV_STATE_UNINITIATED.
         */
        spin_lock_bh(&aq->lock);
        ap_zapq(aq->qid);
        aq->dev_state = AP_DEV_STATE_UNINITIATED;
        spin_unlock_bh(&aq->lock);
}

void ap_queue_init_state(struct ap_queue *aq)
{
        spin_lock_bh(&aq->lock);
        aq->dev_state = AP_DEV_STATE_OPERATING;
        aq->sm_state = AP_SM_STATE_RESET_START;
        ap_wait(ap_sm_event(aq, AP_SM_EVENT_POLL));
        spin_unlock_bh(&aq->lock);
}
EXPORT_SYMBOL(ap_queue_init_state);