text: // 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"
  
  /**
   * 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,
  	  unsigned int special)
  {
  	if (special == 1)
  		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);
  	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_wait ap_sm_nop(struct ap_queue *aq)
  {
  	return AP_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_WAIT_NONE, AP_WAIT_AGAIN, or AP_WAIT_INTERRUPT
   */
  static struct ap_queue_status ap_sm_recv(struct ap_queue *aq)
  {
  	struct ap_queue_status status;
  	struct ap_message *ap_msg;
  
  	status = ap_dqap(aq->qid, &aq->reply->psmid,
  			 aq->reply->message, aq->reply->length);
  	switch (status.response_code) {
  	case AP_RESPONSE_NORMAL:
  		aq->queue_count--;
  		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--;
  			ap_msg->receive(aq, ap_msg, aq->reply);
  			break;
  		}
  	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_WAIT_NONE, AP_WAIT_AGAIN, or AP_WAIT_INTERRUPT
   */
  static enum ap_wait ap_sm_read(struct ap_queue *aq)
  {
  	struct ap_queue_status status;
  
  	if (!aq->reply)
  		return AP_WAIT_NONE;
  	status = ap_sm_recv(aq);
  	switch (status.response_code) {
  	case AP_RESPONSE_NORMAL:
  		if (aq->queue_count > 0) {
  			aq->state = AP_STATE_WORKING;
  			return AP_WAIT_AGAIN;
  		}
  		aq->state = AP_STATE_IDLE;
  		return AP_WAIT_NONE;
  	case AP_RESPONSE_NO_PENDING_REPLY:
  		if (aq->queue_count > 0)
  			return AP_WAIT_INTERRUPT;
  		aq->state = AP_STATE_IDLE;
  		return AP_WAIT_NONE;
  	default:
  		aq->state = AP_STATE_BORKED;
  		return AP_WAIT_NONE;
  	}
  }
  
  /**
   * ap_sm_suspend_read(): Receive pending reply messages from an AP queue
   * without changing the device state in between. In suspend mode we don't
   * allow sending new requests, therefore just fetch pending replies.
   * @aq: pointer to the AP queue
   *
   * Returns AP_WAIT_NONE or AP_WAIT_AGAIN
   */
  static enum ap_wait ap_sm_suspend_read(struct ap_queue *aq)
  {
  	struct ap_queue_status status;
  
  	if (!aq->reply)
  		return AP_WAIT_NONE;
  	status = ap_sm_recv(aq);
  	switch (status.response_code) {
  	case AP_RESPONSE_NORMAL:
  		if (aq->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 queue.
   * @aq: pointer to the AP queue
   *
   * Returns AP_WAIT_NONE, AP_WAIT_AGAIN, or AP_WAIT_INTERRUPT
   */
  static enum ap_wait ap_sm_write(struct ap_queue *aq)
  {
  	struct ap_queue_status status;
  	struct ap_message *ap_msg;
  
  	if (aq->requestq_count <= 0)
  		return AP_WAIT_NONE;
  	/* Start the next request on the queue. */
  	ap_msg = list_entry(aq->requestq.next, struct ap_message, list);
  	status = __ap_send(aq->qid, ap_msg->psmid,
  			   ap_msg->message, ap_msg->length, ap_msg->special);
  	switch (status.response_code) {
  	case AP_RESPONSE_NORMAL:
  		aq->queue_count++;
  		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->state = AP_STATE_WORKING;
  			return AP_WAIT_AGAIN;
  		}
  		/* fall through */
  	case AP_RESPONSE_Q_FULL:
  		aq->state = AP_STATE_QUEUE_FULL;
  		return AP_WAIT_INTERRUPT;
  	case AP_RESPONSE_RESET_IN_PROGRESS:
  		aq->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);
  		aq->requestq_count--;
  		ap_msg->rc = -EINVAL;
  		ap_msg->receive(aq, ap_msg, NULL);
  		return AP_WAIT_AGAIN;
  	default:
  		aq->state = AP_STATE_BORKED;
  		return AP_WAIT_NONE;
  	}
  }
  
  /**
   * ap_sm_read_write(): Send and receive messages to/from an AP queue.
   * @aq: pointer to the AP queue
   *
   * Returns AP_WAIT_NONE, AP_WAIT_AGAIN, or AP_WAIT_INTERRUPT
   */
  static enum ap_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_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->state = AP_STATE_RESET_WAIT;
  		aq->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:
  		aq->state = AP_STATE_BORKED;
  		return AP_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_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->state = AP_STATE_SETIRQ_WAIT;
  		else
  			aq->state = (aq->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:
  		aq->state = AP_STATE_BORKED;
  		return AP_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_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->state = (aq->queue_count > 0) ?
  			AP_STATE_WORKING : AP_STATE_IDLE;
  	}
  
  	switch (status.response_code) {
  	case AP_RESPONSE_NORMAL:
  		if (aq->queue_count > 0)
  			return AP_WAIT_AGAIN;
  		/* fallthrough */
  	case AP_RESPONSE_NO_PENDING_REPLY:
  		return AP_WAIT_TIMEOUT;
  	default:
  		aq->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,
  	},
  };
  
  enum ap_wait ap_sm_event(struct ap_queue *aq, enum ap_event event)
  {
  	return ap_jumptable[aq->state][event](aq);
  }
  
  enum ap_wait ap_sm_event_loop(struct ap_queue *aq, enum ap_event event)
  {
  	enum ap_wait wait;
  
  	while ((wait = ap_sm_event(aq, event)) == AP_WAIT_AGAIN)
  		;
  	return wait;
  }
  
  /*
   * Power management for queue devices
   */
  void ap_queue_suspend(struct ap_device *ap_dev)
  {
  	struct ap_queue *aq = to_ap_queue(&ap_dev->device);
  
  	/* Poll on the device until all requests are finished. */
  	spin_lock_bh(&aq->lock);
  	aq->state = AP_STATE_SUSPEND_WAIT;
  	while (ap_sm_event(aq, AP_EVENT_POLL) != AP_WAIT_NONE)
  		;
  	aq->state = AP_STATE_BORKED;
  	spin_unlock_bh(&aq->lock);
  }
  EXPORT_SYMBOL(ap_queue_suspend);
  
  void ap_queue_resume(struct ap_device *ap_dev)
  {
  }
  EXPORT_SYMBOL(ap_queue_resume);
  
  /*
   * 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);
  	unsigned int req_cnt;
  
  	spin_lock_bh(&aq->lock);
  	req_cnt = aq->total_request_count;
  	spin_unlock_bh(&aq->lock);
  	return snprintf(buf, PAGE_SIZE, "%d\n", req_cnt);
  }
  
  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);
  	reqq_cnt = aq->requestq_count;
  	spin_unlock_bh(&aq->lock);
  	return snprintf(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);
  	penq_cnt = aq->pendingq_count;
  	spin_unlock_bh(&aq->lock);
  	return snprintf(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->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(&aq->lock);
  	return rc;
  }
  
  static DEVICE_ATTR_RO(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->state == AP_STATE_SETIRQ_WAIT)
  		rc = snprintf(buf, PAGE_SIZE, "Enable Interrupt pending.\n");
  	else if (aq->interrupt == AP_INTR_ENABLED)
  		rc = snprintf(buf, PAGE_SIZE, "Interrupts enabled.\n");
  	else
  		rc = snprintf(buf, PAGE_SIZE, "Interrupts disabled.\n");
  	spin_unlock_bh(&aq->lock);
  	return rc;
  }
  
  static DEVICE_ATTR_RO(interrupt);
  
  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,
  	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);
  
  	if (!list_empty(&aq->list)) {
  		spin_lock_bh(&ap_list_lock);
  		list_del_init(&aq->list);
  		spin_unlock_bh(&ap_list_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->state = AP_STATE_RESET_START;
  	aq->interrupt = AP_INTR_DISABLED;
  	spin_lock_init(&aq->lock);
  	INIT_LIST_HEAD(&aq->list);
  	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_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
   */
  void ap_queue_message(struct ap_queue *aq, struct ap_message *ap_msg)
  {
  	/* For asynchronous message handling a valid receive-callback
  	 * is required.
  	 */
  	BUG_ON(!ap_msg->receive);
  
  	spin_lock_bh(&aq->lock);
  	/* Queue the message. */
  	list_add_tail(&ap_msg->list, &aq->requestq);
  	aq->requestq_count++;
  	aq->total_request_count++;
  	atomic_inc(&aq->card->total_request_count);
  	/* Send/receive as many request from the queue as possible. */
  	ap_wait(ap_sm_event_loop(aq, AP_EVENT_POLL));
  	spin_unlock_bh(&aq->lock);
  }
  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);
  	}
  }
  
  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_remove(struct ap_queue *aq)
  {
  	ap_flush_queue(aq);
  	del_timer_sync(&aq->timeout);
  }
  EXPORT_SYMBOL(ap_queue_remove);
  