s390/ap: split ap queue state machine state from device state

The state machine for each ap queue covered a mixture of
device states and state machine (firmware queue state) states.

This patch splits the device states and the state machine
states into two different enums and variables. The major
state is the device state with currently these values:

  AP_DEV_STATE_UNINITIATED - fresh and virgin, not touched
  AP_DEV_STATE_OPERATING   - queue dev is working normal
  AP_DEV_STATE_SHUTDOWN	   - remove/unbind/shutdown in progress
  AP_DEV_STATE_ERROR	   - device is in error state

only when the device state is > UNINITIATED the state machine
is run. The state machine represents the states of the firmware
queue:

  AP_SM_STATE_RESET_START - starting point, reset (RAPQ) ap queue
  AP_SM_STATE_RESET_WAIT  - reset triggered, waiting to be finished
			    if irqs enabled, set up irq (AQIC)
  AP_SM_STATE_SETIRQ_WAIT - enable irq triggered, waiting to be
			    finished, then go to IDLE
  AP_SM_STATE_IDLE	  - queue is operational but empty
  AP_SM_STATE_WORKING	  - queue is operational, requests are stored
			    and replies may wait for getting fetched
  AP_SM_STATE_QUEUE_FULL  - firmware queue is full, so only replies
			    can get fetched

For debugging each ap queue shows a sysfs attribute 'states' which
displays the device and state machine state and is only available
when the kernel is build with CONFIG_ZCRYPT_DEBUG enabled.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

1 files changed, 115 insertions, 40 deletions

diff --git a/drivers/s390/crypto/ap_queue.c b/drivers/s390/crypto/ap_queue.c
index 688ebebbf98c..e7ecbcc18db3 100644
--- a/drivers/s390/crypto/ap_queue.c
+++ b/drivers/s390/crypto/ap_queue.c
@@ -195,7 +195,7 @@ static enum ap_sm_wait ap_sm_read(struct ap_queue *aq)
 		aq->sm_state = AP_SM_STATE_IDLE;
 		return AP_SM_WAIT_NONE;
 	default:
-		aq->sm_state = AP_SM_STATE_BORKED;
+		aq->dev_state = AP_DEV_STATE_ERROR;
 		return AP_SM_WAIT_NONE;
 	}
 }
@@ -245,7 +245,7 @@ static enum ap_sm_wait ap_sm_write(struct ap_queue *aq)
 		ap_msg->receive(aq, ap_msg, NULL);
 		return AP_SM_WAIT_AGAIN;
 	default:
-		aq->sm_state = AP_SM_STATE_BORKED;
+		aq->dev_state = AP_DEV_STATE_ERROR;
 		return AP_SM_WAIT_NONE;
 	}
 }
@@ -284,7 +284,7 @@ static enum ap_sm_wait ap_sm_reset(struct ap_queue *aq)
 	case AP_RESPONSE_DECONFIGURED:
 	case AP_RESPONSE_CHECKSTOPPED:
 	default:
-		aq->sm_state = AP_SM_STATE_BORKED;
+		aq->dev_state = AP_DEV_STATE_ERROR;
 		return AP_SM_WAIT_NONE;
 	}
 }
@@ -323,7 +323,7 @@ static enum ap_sm_wait ap_sm_reset_wait(struct ap_queue *aq)
 	case AP_RESPONSE_DECONFIGURED:
 	case AP_RESPONSE_CHECKSTOPPED:
 	default:
-		aq->sm_state = AP_SM_STATE_BORKED;
+		aq->dev_state = AP_DEV_STATE_ERROR;
 		return AP_SM_WAIT_NONE;
 	}
 }
@@ -360,7 +360,7 @@ static enum ap_sm_wait ap_sm_setirq_wait(struct ap_queue *aq)
 	case AP_RESPONSE_NO_PENDING_REPLY:
 		return AP_SM_WAIT_TIMEOUT;
 	default:
-		aq->sm_state = AP_SM_STATE_BORKED;
+		aq->dev_state = AP_DEV_STATE_ERROR;
 		return AP_SM_WAIT_NONE;
 	}
 }
@@ -393,23 +393,14 @@ static ap_func_t *ap_jumptable[NR_AP_SM_STATES][NR_AP_SM_EVENTS] = {
 		[AP_SM_EVENT_POLL] = ap_sm_read,
 		[AP_SM_EVENT_TIMEOUT] = ap_sm_reset,
 	},
-	[AP_SM_STATE_REMOVE] = {
-		[AP_SM_EVENT_POLL] = ap_sm_nop,
-		[AP_SM_EVENT_TIMEOUT] = ap_sm_nop,
-	},
-	[AP_SM_STATE_UNBOUND] = {
-		[AP_SM_EVENT_POLL] = ap_sm_nop,
-		[AP_SM_EVENT_TIMEOUT] = ap_sm_nop,
-	},
-	[AP_SM_STATE_BORKED] = {
-		[AP_SM_EVENT_POLL] = ap_sm_nop,
-		[AP_SM_EVENT_TIMEOUT] = ap_sm_nop,
-	},
 };
 
 enum ap_sm_wait ap_sm_event(struct ap_queue *aq, enum ap_sm_event event)
 {
-	return ap_jumptable[aq->sm_state][event](aq);
+	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)
@@ -429,12 +420,20 @@ static ssize_t request_count_show(struct device *dev,
 				  char *buf)
 {
 	struct ap_queue *aq = to_ap_queue(dev);
+	bool valid = false;
 	u64 req_cnt;
 
 	spin_lock_bh(&aq->lock);
-	req_cnt = aq->total_request_count;
+	if (aq->dev_state > AP_DEV_STATE_UNINITIATED) {
+		req_cnt = aq->total_request_count;
+		valid = true;
+	}
 	spin_unlock_bh(&aq->lock);
-	return scnprintf(buf, PAGE_SIZE, "%llu\n", req_cnt);
+
+	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,
@@ -459,7 +458,8 @@ static ssize_t requestq_count_show(struct device *dev,
 	unsigned int reqq_cnt = 0;
 
 	spin_lock_bh(&aq->lock);
-	reqq_cnt = aq->requestq_count;
+	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);
 }
@@ -473,7 +473,8 @@ static ssize_t pendingq_count_show(struct device *dev,
 	unsigned int penq_cnt = 0;
 
 	spin_lock_bh(&aq->lock);
-	penq_cnt = aq->pendingq_count;
+	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);
 }
@@ -542,12 +543,79 @@ static ssize_t interrupt_show(struct device *dev,
 
 static DEVICE_ATTR_RO(interrupt);
 
+#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);
+#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,
+#ifdef CONFIG_ZCRYPT_DEBUG
+	&dev_attr_states.attr,
+#endif
 	NULL
 };
 
@@ -587,7 +655,6 @@ struct ap_queue *ap_queue_create(ap_qid_t qid, int device_type)
 	aq->ap_dev.device.type = &ap_queue_type;
 	aq->ap_dev.device_type = device_type;
 	aq->qid = qid;
-	aq->sm_state = AP_SM_STATE_UNBOUND;
 	aq->interrupt = AP_INTR_DISABLED;
 	spin_lock_init(&aq->lock);
 	INIT_LIST_HEAD(&aq->pendingq);
@@ -612,22 +679,30 @@ EXPORT_SYMBOL(ap_queue_init_reply);
  * @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)
+int ap_queue_message(struct ap_queue *aq, struct ap_message *ap_msg)
 {
-	/* For asynchronous message handling a valid receive-callback
-	 * is required.
-	 */
+	int rc = 0;
+
+	/* msg needs to have a valid receive-callback */
 	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++;
-	atomic64_inc(&aq->card->total_request_count);
+
+	/* 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);
 
@@ -698,8 +773,8 @@ void ap_queue_prepare_remove(struct ap_queue *aq)
 	spin_lock_bh(&aq->lock);
 	/* flush queue */
 	__ap_flush_queue(aq);
-	/* set REMOVE state to prevent new messages are queued in */
-	aq->sm_state = AP_SM_STATE_REMOVE;
+	/* 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);
 }
@@ -707,21 +782,21 @@ void ap_queue_prepare_remove(struct ap_queue *aq)
 void ap_queue_remove(struct ap_queue *aq)
 {
 	/*
-	 * all messages have been flushed and the state is
-	 * AP_SM_STATE_REMOVE. Now reset with zero which also
-	 * clears the irq registration and move the state
-	 * to AP_SM_STATE_UNBOUND to signal that this queue
-	 * is not used by any driver currently.
+	 * 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->sm_state = AP_SM_STATE_UNBOUND;
+	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);