GenWQE Character device and DDCB queue

The GenWQE card itself provides access to a generic work queue into
which the work can be put, which should be executed, e.g. compression
or decompression request, or whatever the card was configured to do.

Each request comes with a set of input data (ASV) and will produce some
output data (ASIV). The request will also contain a sequence number,
some timestamps and a command code/subcode plus some fields for hardware-/
software-interaction.

A request can contain references to blocks of memory. Since the card
requires DMA-addresses of that memory, the driver provides two ways to
solve that task:
  1) The drivers mmap() will allocate some DMAable memory for the user.
     The driver has a lookup table such that the virtual userspace
     address can properly be replaced and checked.
  2) The user allocates memory and the driver will pin/unpin that
     memory and setup a scatter gatherlist with matching DMA addresses.

Currently work requests are synchronous.

Signed-off-by: Frank Haverkamp <haver@linux.vnet.ibm.com>
Co-authors: Joerg-Stephan Vogt <jsvogt@de.ibm.com>,
            Michael Jung <MIJUNG@de.ibm.com>,
            Michael Ruettger <michael@ibmra.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1373 insertions, 0 deletions

diff --git a/drivers/misc/genwqe/card_ddcb.c b/drivers/misc/genwqe/card_ddcb.c
new file mode 100644
index 000000000000..cc6fca7a4851
--- /dev/null
+++ b/drivers/misc/genwqe/card_ddcb.c
@@ -0,0 +1,1373 @@
+/**
+ * IBM Accelerator Family 'GenWQE'
+ *
+ * (C) Copyright IBM Corp. 2013
+ *
+ * Author: Frank Haverkamp <haver@linux.vnet.ibm.com>
+ * Author: Joerg-Stephan Vogt <jsvogt@de.ibm.com>
+ * Author: Michael Jung <mijung@de.ibm.com>
+ * Author: Michael Ruettger <michael@ibmra.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ *
+ * 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.
+ */
+
+/*
+ * Device Driver Control Block (DDCB) queue support. Definition of
+ * interrupt handlers for queue support as well as triggering the
+ * health monitor code in case of problems. The current hardware uses
+ * an MSI interrupt which is shared between error handling and
+ * functional code.
+ */
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/pci.h>
+#include <linux/string.h>
+#include <linux/dma-mapping.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/crc-itu-t.h>
+
+#include "card_ddcb.h"
+
+/*
+ * N: next DDCB, this is where the next DDCB will be put.
+ * A: active DDCB, this is where the code will look for the next completion.
+ * x: DDCB is enqueued, we are waiting for its completion.
+
+ * Situation (1): Empty queue
+ *  +---+---+---+---+---+---+---+---+
+ *  | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
+ *  |   |   |   |   |   |   |   |   |
+ *  +---+---+---+---+---+---+---+---+
+ *           A/N
+ *  enqueued_ddcbs = A - N = 2 - 2 = 0
+ *
+ * Situation (2): Wrapped, N > A
+ *  +---+---+---+---+---+---+---+---+
+ *  | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
+ *  |   |   | x | x |   |   |   |   |
+ *  +---+---+---+---+---+---+---+---+
+ *            A       N
+ *  enqueued_ddcbs = N - A = 4 - 2 = 2
+ *
+ * Situation (3): Queue wrapped, A > N
+ *  +---+---+---+---+---+---+---+---+
+ *  | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
+ *  | x | x |   |   | x | x | x | x |
+ *  +---+---+---+---+---+---+---+---+
+ *            N       A
+ *  enqueued_ddcbs = queue_max  - (A - N) = 8 - (4 - 2) = 6
+ *
+ * Situation (4a): Queue full N > A
+ *  +---+---+---+---+---+---+---+---+
+ *  | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
+ *  | x | x | x | x | x | x | x |   |
+ *  +---+---+---+---+---+---+---+---+
+ *    A                           N
+ *
+ *  enqueued_ddcbs = N - A = 7 - 0 = 7
+ *
+ * Situation (4a): Queue full A > N
+ *  +---+---+---+---+---+---+---+---+
+ *  | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
+ *  | x | x | x |   | x | x | x | x |
+ *  +---+---+---+---+---+---+---+---+
+ *                N   A
+ *  enqueued_ddcbs = queue_max - (A - N) = 8 - (4 - 3) = 7
+ */
+
+static int queue_empty(struct ddcb_queue *queue)
+{
+	return queue->ddcb_next == queue->ddcb_act;
+}
+
+static int queue_enqueued_ddcbs(struct ddcb_queue *queue)
+{
+	if (queue->ddcb_next >= queue->ddcb_act)
+		return queue->ddcb_next - queue->ddcb_act;
+
+	return queue->ddcb_max - (queue->ddcb_act - queue->ddcb_next);
+}
+
+static int queue_free_ddcbs(struct ddcb_queue *queue)
+{
+	int free_ddcbs = queue->ddcb_max - queue_enqueued_ddcbs(queue) - 1;
+
+	if (WARN_ON_ONCE(free_ddcbs < 0)) { /* must never ever happen! */
+		return 0;
+	}
+	return free_ddcbs;
+}
+
+/*
+ * Use of the PRIV field in the DDCB for queue debugging:
+ *
+ * (1) Trying to get rid of a DDCB which saw a timeout:
+ *     pddcb->priv[6] = 0xcc;   # cleared
+ *
+ * (2) Append a DDCB via NEXT bit:
+ *     pddcb->priv[7] = 0xaa;	# appended
+ *
+ * (3) DDCB needed tapping:
+ *     pddcb->priv[7] = 0xbb;   # tapped
+ *
+ * (4) DDCB marked as correctly finished:
+ *     pddcb->priv[6] = 0xff;	# finished
+ */
+
+static inline void ddcb_mark_tapped(struct ddcb *pddcb)
+{
+	pddcb->priv[7] = 0xbb;  /* tapped */
+}
+
+static inline void ddcb_mark_appended(struct ddcb *pddcb)
+{
+	pddcb->priv[7] = 0xaa;	/* appended */
+}
+
+static inline void ddcb_mark_cleared(struct ddcb *pddcb)
+{
+	pddcb->priv[6] = 0xcc; /* cleared */
+}
+
+static inline void ddcb_mark_finished(struct ddcb *pddcb)
+{
+	pddcb->priv[6] = 0xff;	/* finished */
+}
+
+static inline void ddcb_mark_unused(struct ddcb *pddcb)
+{
+	pddcb->priv_64 = cpu_to_be64(0); /* not tapped */
+}
+
+/**
+ * genwqe_crc16() - Generate 16-bit crc as required for DDCBs
+ * @buff:       pointer to data buffer
+ * @len:        length of data for calculation
+ * @init:       initial crc (0xffff at start)
+ *
+ * Polynomial = x^16 + x^12 + x^5 + 1   (0x1021)
+ * Example: 4 bytes 0x01 0x02 0x03 0x04 with init = 0xffff
+ *          should result in a crc16 of 0x89c3
+ *
+ * Return: crc16 checksum in big endian format !
+ */
+static inline u16 genwqe_crc16(const u8 *buff, size_t len, u16 init)
+{
+	return crc_itu_t(init, buff, len);
+}
+
+static void print_ddcb_info(struct genwqe_dev *cd, struct ddcb_queue *queue)
+{
+	int i;
+	struct ddcb *pddcb;
+	unsigned long flags;
+	struct pci_dev *pci_dev = cd->pci_dev;
+
+	spin_lock_irqsave(&cd->print_lock, flags);
+
+	dev_info(&pci_dev->dev,
+		 "DDCB list for card #%d (ddcb_act=%d / ddcb_next=%d):\n",
+		 cd->card_idx, queue->ddcb_act, queue->ddcb_next);
+
+	pddcb = queue->ddcb_vaddr;
+	for (i = 0; i < queue->ddcb_max; i++) {
+		dev_err(&pci_dev->dev,
+			"  %c %-3d: RETC=%03x SEQ=%04x "
+			"HSI=%02X SHI=%02x PRIV=%06llx CMD=%03x\n",
+			i == queue->ddcb_act ? '>' : ' ',
+			i,
+			be16_to_cpu(pddcb->retc_16),
+			be16_to_cpu(pddcb->seqnum_16),
+			pddcb->hsi,
+			pddcb->shi,
+			be64_to_cpu(pddcb->priv_64),
+			pddcb->cmd);
+		pddcb++;
+	}
+	spin_unlock_irqrestore(&cd->print_lock, flags);
+}
+
+struct genwqe_ddcb_cmd *ddcb_requ_alloc(void)
+{
+	struct ddcb_requ *req;
+
+	req = kzalloc(sizeof(*req), GFP_ATOMIC);
+	if (!req)
+		return NULL;
+
+	return &req->cmd;
+}
+
+void ddcb_requ_free(struct genwqe_ddcb_cmd *cmd)
+{
+	struct ddcb_requ *req = container_of(cmd, struct ddcb_requ, cmd);
+	kfree(req);
+}
+
+static inline enum genwqe_requ_state ddcb_requ_get_state(struct ddcb_requ *req)
+{
+	return req->req_state;
+}
+
+static inline void ddcb_requ_set_state(struct ddcb_requ *req,
+				       enum genwqe_requ_state new_state)
+{
+	req->req_state = new_state;
+}
+
+static inline int ddcb_requ_collect_debug_data(struct ddcb_requ *req)
+{
+	return req->cmd.ddata_addr != 0x0;
+}
+
+/**
+ * ddcb_requ_finished() - Returns the hardware state of the associated DDCB
+ * @cd:          pointer to genwqe device descriptor
+ * @req:         DDCB work request
+ *
+ * Status of ddcb_requ mirrors this hardware state, but is copied in
+ * the ddcb_requ on interrupt/polling function. The lowlevel code
+ * should check the hardware state directly, the higher level code
+ * should check the copy.
+ *
+ * This function will also return true if the state of the queue is
+ * not GENWQE_CARD_USED. This enables us to purge all DDCBs in the
+ * shutdown case.
+ */
+static int ddcb_requ_finished(struct genwqe_dev *cd, struct ddcb_requ *req)
+{
+	return (ddcb_requ_get_state(req) == GENWQE_REQU_FINISHED) ||
+		(cd->card_state != GENWQE_CARD_USED);
+}
+
+/**
+ * enqueue_ddcb() - Enqueue a DDCB
+ * @cd:         pointer to genwqe device descriptor
+ * @queue:	queue this operation should be done on
+ * @ddcb_no:    pointer to ddcb number being tapped
+ *
+ * Start execution of DDCB by tapping or append to queue via NEXT
+ * bit. This is done by an atomic 'compare and swap' instruction and
+ * checking SHI and HSI of the previous DDCB.
+ *
+ * This function must only be called with ddcb_lock held.
+ *
+ * Return: 1 if new DDCB is appended to previous
+ *         2 if DDCB queue is tapped via register/simulation
+ */
+#define RET_DDCB_APPENDED 1
+#define RET_DDCB_TAPPED   2
+
+static int enqueue_ddcb(struct genwqe_dev *cd, struct ddcb_queue *queue,
+			struct ddcb *pddcb, int ddcb_no)
+{
+	unsigned int try;
+	int prev_no;
+	struct ddcb *prev_ddcb;
+	u32 old, new, icrc_hsi_shi;
+	u64 num;
+
+	/*
+	 * For performance checks a Dispatch Timestamp can be put into
+	 * DDCB It is supposed to use the SLU's free running counter,
+	 * but this requires PCIe cycles.
+	 */
+	ddcb_mark_unused(pddcb);
+
+	/* check previous DDCB if already fetched */
+	prev_no = (ddcb_no == 0) ? queue->ddcb_max - 1 : ddcb_no - 1;
+	prev_ddcb = &queue->ddcb_vaddr[prev_no];
+
+	/*
+	 * It might have happened that the HSI.FETCHED bit is
+	 * set. Retry in this case. Therefore I expect maximum 2 times
+	 * trying.
+	 */
+	ddcb_mark_appended(pddcb);
+	for (try = 0; try < 2; try++) {
+		old = prev_ddcb->icrc_hsi_shi_32; /* read SHI/HSI in BE32 */
+
+		/* try to append via NEXT bit if prev DDCB is not completed */
+		if ((old & DDCB_COMPLETED_BE32) != 0x00000000)
+			break;
+
+		new = (old | DDCB_NEXT_BE32);
+		icrc_hsi_shi = cmpxchg(&prev_ddcb->icrc_hsi_shi_32, old, new);
+
+		if (icrc_hsi_shi == old)
+			return RET_DDCB_APPENDED; /* appended to queue */
+	}
+
+	/* Queue must be re-started by updating QUEUE_OFFSET */
+	ddcb_mark_tapped(pddcb);
+	num = (u64)ddcb_no << 8;
+	__genwqe_writeq(cd, queue->IO_QUEUE_OFFSET, num); /* start queue */
+
+	return RET_DDCB_TAPPED;
+}
+
+/**
+ * copy_ddcb_results() - Copy output state from real DDCB to request
+ *
+ * Copy DDCB ASV to request struct. There is no endian
+ * conversion made, since data structure in ASV is still
+ * unknown here.
+ *
+ * This is needed by:
+ *   - genwqe_purge_ddcb()
+ *   - genwqe_check_ddcb_queue()
+ */
+static void copy_ddcb_results(struct ddcb_requ *req, int ddcb_no)
+{
+	struct ddcb_queue *queue = req->queue;
+	struct ddcb *pddcb = &queue->ddcb_vaddr[req->num];
+
+	memcpy(&req->cmd.asv[0], &pddcb->asv[0], DDCB_ASV_LENGTH);
+
+	/* copy status flags of the variant part */
+	req->cmd.vcrc     = be16_to_cpu(pddcb->vcrc_16);
+	req->cmd.deque_ts = be64_to_cpu(pddcb->deque_ts_64);
+	req->cmd.cmplt_ts = be64_to_cpu(pddcb->cmplt_ts_64);
+
+	req->cmd.attn     = be16_to_cpu(pddcb->attn_16);
+	req->cmd.progress = be32_to_cpu(pddcb->progress_32);
+	req->cmd.retc     = be16_to_cpu(pddcb->retc_16);
+
+	if (ddcb_requ_collect_debug_data(req)) {
+		int prev_no = (ddcb_no == 0) ?
+			queue->ddcb_max - 1 : ddcb_no - 1;
+		struct ddcb *prev_pddcb = &queue->ddcb_vaddr[prev_no];
+
+		memcpy(&req->debug_data.ddcb_finished, pddcb,
+		       sizeof(req->debug_data.ddcb_finished));
+		memcpy(&req->debug_data.ddcb_prev, prev_pddcb,
+		       sizeof(req->debug_data.ddcb_prev));
+	}
+}
+
+/**
+ * genwqe_check_ddcb_queue() - Checks DDCB queue for completed work equests.
+ * @cd:         pointer to genwqe device descriptor
+ *
+ * Return: Number of DDCBs which were finished
+ */
+static int genwqe_check_ddcb_queue(struct genwqe_dev *cd,
+				   struct ddcb_queue *queue)
+{
+	unsigned long flags;
+	int ddcbs_finished = 0;
+	struct pci_dev *pci_dev = cd->pci_dev;
+
+	spin_lock_irqsave(&queue->ddcb_lock, flags);
+
+	/* FIXME avoid soft locking CPU */
+	while (!queue_empty(queue) && (ddcbs_finished < queue->ddcb_max)) {
+
+		struct ddcb *pddcb;
+		struct ddcb_requ *req;
+		u16 vcrc, vcrc_16, retc_16;
+
+		pddcb = &queue->ddcb_vaddr[queue->ddcb_act];
+
+		if ((pddcb->icrc_hsi_shi_32 & DDCB_COMPLETED_BE32) ==
+		    0x00000000)
+			goto go_home; /* not completed, continue waiting */
+
+		/* Note: DDCB could be purged */
+
+		req = queue->ddcb_req[queue->ddcb_act];
+		if (req == NULL) {
+			/* this occurs if DDCB is purged, not an error */
+			/* Move active DDCB further; Nothing to do anymore. */
+			goto pick_next_one;
+		}
+
+		/*
+		 * HSI=0x44 (fetched and completed), but RETC is
+		 * 0x101, or even worse 0x000.
+		 *
+		 * In case of seeing the queue in inconsistent state
+		 * we read the errcnts and the queue status to provide
+		 * a trigger for our PCIe analyzer stop capturing.
+		 */
+		retc_16 = be16_to_cpu(pddcb->retc_16);
+		if ((pddcb->hsi == 0x44) && (retc_16 <= 0x101)) {
+			u64 errcnts, status;
+			u64 ddcb_offs = (u64)pddcb - (u64)queue->ddcb_vaddr;
+
+			errcnts = __genwqe_readq(cd, queue->IO_QUEUE_ERRCNTS);
+			status  = __genwqe_readq(cd, queue->IO_QUEUE_STATUS);
+
+			dev_err(&pci_dev->dev,
+				"[%s] SEQN=%04x HSI=%02x RETC=%03x "
+				" Q_ERRCNTS=%016llx Q_STATUS=%016llx\n"
+				" DDCB_DMA_ADDR=%016llx\n",
+				__func__, be16_to_cpu(pddcb->seqnum_16),
+				pddcb->hsi, retc_16, errcnts, status,
+				queue->ddcb_daddr + ddcb_offs);
+		}
+
+		copy_ddcb_results(req, queue->ddcb_act);
+		queue->ddcb_req[queue->ddcb_act] = NULL; /* take from queue */
+
+		dev_dbg(&pci_dev->dev, "FINISHED DDCB#%d\n", req->num);
+		genwqe_hexdump(pci_dev, pddcb, sizeof(*pddcb));
+
+		ddcb_mark_finished(pddcb);
+
+		/* calculate CRC_16 to see if VCRC is correct */
+		vcrc = genwqe_crc16(pddcb->asv,
+				   VCRC_LENGTH(req->cmd.asv_length),
+				   0xffff);
+		vcrc_16 = be16_to_cpu(pddcb->vcrc_16);
+		if (vcrc != vcrc_16) {
+			printk_ratelimited(KERN_ERR
+				"%s %s: err: wrong VCRC pre=%02x vcrc_len=%d "
+				"bytes vcrc_data=%04x is not vcrc_card=%04x\n",
+				GENWQE_DEVNAME, dev_name(&pci_dev->dev),
+				pddcb->pre, VCRC_LENGTH(req->cmd.asv_length),
+				vcrc, vcrc_16);
+		}
+
+		ddcb_requ_set_state(req, GENWQE_REQU_FINISHED);
+		queue->ddcbs_completed++;
+		queue->ddcbs_in_flight--;
+
+		/* wake up process waiting for this DDCB */
+		wake_up_interruptible(&queue->ddcb_waitqs[queue->ddcb_act]);
+
+pick_next_one:
+		queue->ddcb_act = (queue->ddcb_act + 1) % queue->ddcb_max;
+		ddcbs_finished++;
+	}
+
+ go_home:
+	spin_unlock_irqrestore(&queue->ddcb_lock, flags);
+	return ddcbs_finished;
+}
+
+/**
+ * __genwqe_wait_ddcb(): Waits until DDCB is completed
+ * @cd:         pointer to genwqe device descriptor
+ * @req:        pointer to requsted DDCB parameters
+ *
+ * The Service Layer will update the RETC in DDCB when processing is
+ * pending or done.
+ *
+ * Return: > 0 remaining jiffies, DDCB completed
+ *           -ETIMEDOUT	when timeout
+ *           -ERESTARTSYS when ^C
+ *           -EINVAL when unknown error condition
+ *
+ * When an error is returned the called needs to ensure that
+ * purge_ddcb() is being called to get the &req removed from the
+ * queue.
+ */
+int __genwqe_wait_ddcb(struct genwqe_dev *cd, struct ddcb_requ *req)
+{
+	int rc;
+	unsigned int ddcb_no;
+	struct ddcb_queue *queue;
+	struct pci_dev *pci_dev = cd->pci_dev;
+
+	if (req == NULL)
+		return -EINVAL;
+
+	queue = req->queue;
+	if (queue == NULL)
+		return -EINVAL;
+
+	ddcb_no = req->num;
+	if (ddcb_no >= queue->ddcb_max)
+		return -EINVAL;
+
+	rc = wait_event_interruptible_timeout(queue->ddcb_waitqs[ddcb_no],
+				ddcb_requ_finished(cd, req),
+				genwqe_ddcb_software_timeout * HZ);
+
+	/*
+	 * We need to distinguish 3 cases here:
+	 *   1. rc == 0              timeout occured
+	 *   2. rc == -ERESTARTSYS   signal received
+	 *   3. rc > 0               remaining jiffies condition is true
+	 */
+	if (rc == 0) {
+		struct ddcb_queue *queue = req->queue;
+		struct ddcb *pddcb;
+
+		/*
+		 * Timeout may be caused by long task switching time.
+		 * When timeout happens, check if the request has
+		 * meanwhile completed.
+		 */
+		genwqe_check_ddcb_queue(cd, req->queue);
+		if (ddcb_requ_finished(cd, req))
+			return rc;
+
+		dev_err(&pci_dev->dev,
+			"[%s] err: DDCB#%d timeout rc=%d state=%d req @ %p\n",
+			__func__, req->num, rc,	ddcb_requ_get_state(req),
+			req);
+		dev_err(&pci_dev->dev,
+			"[%s]      IO_QUEUE_STATUS=0x%016llx\n", __func__,
+			__genwqe_readq(cd, queue->IO_QUEUE_STATUS));
+
+		pddcb = &queue->ddcb_vaddr[req->num];
+		genwqe_hexdump(pci_dev, pddcb, sizeof(*pddcb));
+
+		print_ddcb_info(cd, req->queue);
+		return -ETIMEDOUT;
+
+	} else if (rc == -ERESTARTSYS) {
+		return rc;
+		/*
+		 * EINTR:       Stops the application
+		 * ERESTARTSYS: Restartable systemcall; called again
+		 */
+
+	} else if (rc < 0) {
+		dev_err(&pci_dev->dev,
+			"[%s] err: DDCB#%d unknown result (rc=%d) %d!\n",
+			__func__, req->num, rc, ddcb_requ_get_state(req));
+		return -EINVAL;
+	}
+
+	/* Severe error occured. Driver is forced to stop operation */
+	if (cd->card_state != GENWQE_CARD_USED) {
+		dev_err(&pci_dev->dev,
+			"[%s] err: DDCB#%d forced to stop (rc=%d)\n",
+			__func__, req->num, rc);
+		return -EIO;
+	}
+	return rc;
+}
+
+/**
+ * get_next_ddcb() - Get next available DDCB
+ * @cd:         pointer to genwqe device descriptor
+ *
+ * DDCB's content is completely cleared but presets for PRE and
+ * SEQNUM. This function must only be called when ddcb_lock is held.
+ *
+ * Return: NULL if no empty DDCB available otherwise ptr to next DDCB.
+ */
+static struct ddcb *get_next_ddcb(struct genwqe_dev *cd,
+				  struct ddcb_queue *queue,
+				  int *num)
+{
+	u64 *pu64;
+	struct ddcb *pddcb;
+
+	if (queue_free_ddcbs(queue) == 0) /* queue is  full */
+		return NULL;
+
+	/* find new ddcb */
+	pddcb = &queue->ddcb_vaddr[queue->ddcb_next];
+
+	/* if it is not completed, we are not allowed to use it */
+	/* barrier(); */
+	if ((pddcb->icrc_hsi_shi_32 & DDCB_COMPLETED_BE32) == 0x00000000)
+		return NULL;
+
+	*num = queue->ddcb_next;	/* internal DDCB number */
+	queue->ddcb_next = (queue->ddcb_next + 1) % queue->ddcb_max;
+
+	/* clear important DDCB fields */
+	pu64 = (u64 *)pddcb;
+	pu64[0] = 0ULL;		/* offs 0x00 (ICRC,HSI,SHI,...) */
+	pu64[1] = 0ULL;		/* offs 0x01 (ACFUNC,CMD...) */
+
+	/* destroy previous results in ASV */
+	pu64[0x80/8] = 0ULL;	/* offs 0x80 (ASV + 0) */
+	pu64[0x88/8] = 0ULL;	/* offs 0x88 (ASV + 0x08) */
+	pu64[0x90/8] = 0ULL;	/* offs 0x90 (ASV + 0x10) */
+	pu64[0x98/8] = 0ULL;	/* offs 0x98 (ASV + 0x18) */
+	pu64[0xd0/8] = 0ULL;	/* offs 0xd0 (RETC,ATTN...) */
+
+	pddcb->pre = DDCB_PRESET_PRE; /* 128 */
+	pddcb->seqnum_16 = cpu_to_be16(queue->ddcb_seq++);
+	return pddcb;
+}
+
+/**
+ * __genwqe_purge_ddcb() - Remove a DDCB from the workqueue
+ * @cd:         genwqe device descriptor
+ * @req:        DDCB request
+ *
+ * This will fail when the request was already FETCHED. In this case
+ * we need to wait until it is finished. Else the DDCB can be
+ * reused. This function also ensures that the request data structure
+ * is removed from ddcb_req[].
+ *
+ * Do not forget to call this function when genwqe_wait_ddcb() fails,
+ * such that the request gets really removed from ddcb_req[].
+ *
+ * Return: 0 success
+ */
+int __genwqe_purge_ddcb(struct genwqe_dev *cd, struct ddcb_requ *req)
+{
+	struct ddcb *pddcb = NULL;
+	unsigned int t;
+	unsigned long flags;
+	struct ddcb_queue *queue = req->queue;
+	struct pci_dev *pci_dev = cd->pci_dev;
+	u32 icrc_hsi_shi = 0x0000;
+	u64 queue_status;
+	u32 old, new;
+
+	/* unsigned long flags; */
+	if (genwqe_ddcb_software_timeout <= 0) {
+		dev_err(&pci_dev->dev,
+			"[%s] err: software timeout is not set!\n", __func__);
+		return -EFAULT;
+	}
+
+	pddcb = &queue->ddcb_vaddr[req->num];
+
+	for (t = 0; t < genwqe_ddcb_software_timeout * 10; t++) {
+
+		spin_lock_irqsave(&queue->ddcb_lock, flags);
+
+		/* Check if req was meanwhile finished */
+		if (ddcb_requ_get_state(req) == GENWQE_REQU_FINISHED)
+			goto go_home;
+
+		/* try to set PURGE bit if FETCHED/COMPLETED are not set */
+		old = pddcb->icrc_hsi_shi_32;	/* read SHI/HSI in BE32 */
+		if ((old & DDCB_FETCHED_BE32) == 0x00000000) {
+
+			new = (old | DDCB_PURGE_BE32);
+			icrc_hsi_shi = cmpxchg(&pddcb->icrc_hsi_shi_32,
+					       old, new);
+			if (icrc_hsi_shi == old)
+				goto finish_ddcb;
+		}
+
+		/* normal finish with HSI bit */
+		barrier();
+		icrc_hsi_shi = pddcb->icrc_hsi_shi_32;
+		if (icrc_hsi_shi & DDCB_COMPLETED_BE32)
+			goto finish_ddcb;
+
+		spin_unlock_irqrestore(&queue->ddcb_lock, flags);
+
+		/*
+		 * Here the check_ddcb() function will most likely
+		 * discover this DDCB to be finished some point in
+		 * time. It will mark the req finished and free it up
+		 * in the list.
+		 */
+
+		copy_ddcb_results(req, req->num); /* for the failing case */
+		msleep(100); /* sleep for 1/10 second and try again */
+		continue;
+
+finish_ddcb:
+		copy_ddcb_results(req, req->num);
+		ddcb_requ_set_state(req, GENWQE_REQU_FINISHED);
+		queue->ddcbs_in_flight--;
+		queue->ddcb_req[req->num] = NULL; /* delete from array */
+		ddcb_mark_cleared(pddcb);
+
+		/* Move active DDCB further; Nothing to do here anymore. */
+
+		/*
+		 * We need to ensure that there is at least one free
+		 * DDCB in the queue. To do that, we must update
+		 * ddcb_act only if the COMPLETED bit is set for the
+		 * DDCB we are working on else we treat that DDCB even
+		 * if we PURGED it as occupied (hardware is supposed
+		 * to set the COMPLETED bit yet!).
+		 */
+		icrc_hsi_shi = pddcb->icrc_hsi_shi_32;
+		if ((icrc_hsi_shi & DDCB_COMPLETED_BE32) &&
+		    (queue->ddcb_act == req->num)) {
+			queue->ddcb_act = ((queue->ddcb_act + 1) %
+					   queue->ddcb_max);
+		}
+go_home:
+		spin_unlock_irqrestore(&queue->ddcb_lock, flags);
+		return 0;
+	}
+
+	/*
+	 * If the card is dead and the queue is forced to stop, we
+	 * might see this in the queue status register.
+	 */
+	queue_status = __genwqe_readq(cd, queue->IO_QUEUE_STATUS);
+
+	dev_dbg(&pci_dev->dev, "UN/FINISHED DDCB#%d\n", req->num);
+	genwqe_hexdump(pci_dev, pddcb, sizeof(*pddcb));
+
+	dev_err(&pci_dev->dev,
+		"[%s] err: DDCB#%d not purged and not completed "
+		"after %d seconds QSTAT=%016llx!!\n",
+		__func__, req->num, genwqe_ddcb_software_timeout,
+		queue_status);
+
+	print_ddcb_info(cd, req->queue);
+
+	return -EFAULT;
+}
+
+int genwqe_init_debug_data(struct genwqe_dev *cd, struct genwqe_debug_data *d)
+{
+	int len;
+	struct pci_dev *pci_dev = cd->pci_dev;
+
+	if (d == NULL) {
+		dev_err(&pci_dev->dev,
+			"[%s] err: invalid memory for debug data!\n",
+			__func__);
+		return -EFAULT;
+	}
+
+	len  = sizeof(d->driver_version);
+	snprintf(d->driver_version, len, "%s", DRV_VERS_STRING);
+	d->slu_unitcfg = cd->slu_unitcfg;
+	d->app_unitcfg = cd->app_unitcfg;
+	return 0;
+}
+
+/**
+ * __genwqe_enqueue_ddcb() - Enqueue a DDCB
+ * @cd:          pointer to genwqe device descriptor
+ * @req:         pointer to DDCB execution request
+ *
+ * Return: 0 if enqueuing succeeded
+ *         -EIO if card is unusable/PCIe problems
+ *         -EBUSY if enqueuing failed
+ */
+int __genwqe_enqueue_ddcb(struct genwqe_dev *cd, struct ddcb_requ *req)
+{
+	struct ddcb *pddcb;
+	unsigned long flags;
+	struct ddcb_queue *queue;
+	struct pci_dev *pci_dev = cd->pci_dev;
+	u16 icrc;
+
+	if (cd->card_state != GENWQE_CARD_USED) {
+		printk_ratelimited(KERN_ERR
+			"%s %s: [%s] Card is unusable/PCIe problem Req#%d\n",
+			GENWQE_DEVNAME, dev_name(&pci_dev->dev),
+			__func__, req->num);
+		return -EIO;
+	}
+
+	queue = req->queue = &cd->queue;
+
+	/* FIXME circumvention to improve performance when no irq is
+	 * there.
+	 */
+	if (genwqe_polling_enabled)
+		genwqe_check_ddcb_queue(cd, queue);
+
+	/*
+	 * It must be ensured to process all DDCBs in successive
+	 * order. Use a lock here in order to prevent nested DDCB
+	 * enqueuing.
+	 */
+	spin_lock_irqsave(&queue->ddcb_lock, flags);
+
+	pddcb = get_next_ddcb(cd, queue, &req->num);	/* get ptr and num */
+	if (pddcb == NULL) {
+		spin_unlock_irqrestore(&queue->ddcb_lock, flags);
+		queue->busy++;
+		return -EBUSY;
+	}
+
+	if (queue->ddcb_req[req->num] != NULL) {
+		spin_unlock_irqrestore(&queue->ddcb_lock, flags);
+
+		dev_err(&pci_dev->dev,
+			"[%s] picked DDCB %d with req=%p still in use!!\n",
+			__func__, req->num, req);
+		return -EFAULT;
+	}
+	ddcb_requ_set_state(req, GENWQE_REQU_ENQUEUED);
+	queue->ddcb_req[req->num] = req;
+
+	pddcb->cmdopts_16 = cpu_to_be16(req->cmd.cmdopts);
+	pddcb->cmd = req->cmd.cmd;
+	pddcb->acfunc = req->cmd.acfunc;	/* functional unit */
+
+	/*
+	 * We know that we can get retc 0x104 with CRC error, do not
+	 * stop the queue in those cases for this command. XDIR = 1
+	 * does not work for old SLU versions.
+	 *
+	 * Last bitstream with the old XDIR behavior had SLU_ID
+	 * 0x34199.
+	 */
+	if ((cd->slu_unitcfg & 0xFFFF0ull) > 0x34199ull)
+		pddcb->xdir = 0x1;
+	else
+		pddcb->xdir = 0x0;
+
+
+	pddcb->psp = (((req->cmd.asiv_length / 8) << 4) |
+		      ((req->cmd.asv_length  / 8)));
+	pddcb->disp_ts_64 = cpu_to_be64(req->cmd.disp_ts);
+
+	/*
+	 * If copying the whole DDCB_ASIV_LENGTH is impacting
+	 * performance we need to change it to
+	 * req->cmd.asiv_length. But simulation benefits from some
+	 * non-architectured bits behind the architectured content.
+	 *
+	 * How much data is copied depends on the availability of the
+	 * ATS field, which was introduced late. If the ATS field is
+	 * supported ASIV is 8 bytes shorter than it used to be. Since
+	 * the ATS field is copied too, the code should do exactly
+	 * what it did before, but I wanted to make copying of the ATS
+	 * field very explicit.
+	 */
+	if (genwqe_get_slu_id(cd) <= 0x2) {
+		memcpy(&pddcb->__asiv[0],	/* destination */
+		       &req->cmd.__asiv[0],	/* source */
+		       DDCB_ASIV_LENGTH);	/* req->cmd.asiv_length */
+	} else {
+		pddcb->n.ats_64 = req->cmd.ats;
+		memcpy(&pddcb->n.asiv[0],		/* destination */
+			&req->cmd.asiv[0],	/* source */
+			DDCB_ASIV_LENGTH_ATS);	/* req->cmd.asiv_length */
+	}
+
+	pddcb->icrc_hsi_shi_32 = cpu_to_be32(0x00000000); /* for crc */
+
+	/*
+	 * Calculate CRC_16 for corresponding range PSP(7:4). Include
+	 * empty 4 bytes prior to the data.
+	 */
+	icrc = genwqe_crc16((const u8 *)pddcb,
+			   ICRC_LENGTH(req->cmd.asiv_length), 0xffff);
+	pddcb->icrc_hsi_shi_32 = cpu_to_be32((u32)icrc << 16);
+
+	/* enable DDCB completion irq */
+	if (!genwqe_polling_enabled)
+		pddcb->icrc_hsi_shi_32 |= DDCB_INTR_BE32;
+
+	dev_dbg(&pci_dev->dev, "INPUT DDCB#%d\n", req->num);
+	genwqe_hexdump(pci_dev, pddcb, sizeof(*pddcb));
+
+	if (ddcb_requ_collect_debug_data(req)) {
+		/* use the kernel copy of debug data. copying back to
+		   user buffer happens later */
+
+		genwqe_init_debug_data(cd, &req->debug_data);
+		memcpy(&req->debug_data.ddcb_before, pddcb,
+		       sizeof(req->debug_data.ddcb_before));
+	}
+
+	enqueue_ddcb(cd, queue, pddcb, req->num);
+	queue->ddcbs_in_flight++;
+
+	if (queue->ddcbs_in_flight > queue->ddcbs_max_in_flight)
+		queue->ddcbs_max_in_flight = queue->ddcbs_in_flight;
+
+	ddcb_requ_set_state(req, GENWQE_REQU_TAPPED);
+	spin_unlock_irqrestore(&queue->ddcb_lock, flags);
+	wake_up_interruptible(&cd->queue_waitq);
+
+	return 0;
+}
+
+/**
+ * __genwqe_execute_raw_ddcb() - Setup and execute DDCB
+ * @cd:         pointer to genwqe device descriptor
+ * @req:        user provided DDCB request
+ */
+int __genwqe_execute_raw_ddcb(struct genwqe_dev *cd,
+			     struct genwqe_ddcb_cmd *cmd)
+{
+	int rc = 0;
+	struct pci_dev *pci_dev = cd->pci_dev;
+	struct ddcb_requ *req = container_of(cmd, struct ddcb_requ, cmd);
+
+	if (cmd->asiv_length > DDCB_ASIV_LENGTH) {
+		dev_err(&pci_dev->dev, "[%s] err: wrong asiv_length of %d\n",
+			__func__, cmd->asiv_length);
+		return -EINVAL;
+	}
+	if (cmd->asv_length > DDCB_ASV_LENGTH) {
+		dev_err(&pci_dev->dev, "[%s] err: wrong asv_length of %d\n",
+			__func__, cmd->asiv_length);
+		return -EINVAL;
+	}
+	rc = __genwqe_enqueue_ddcb(cd, req);
+	if (rc != 0)
+		return rc;
+
+	rc = __genwqe_wait_ddcb(cd, req);
+	if (rc < 0)		/* error or signal interrupt */
+		goto err_exit;
+
+	if (ddcb_requ_collect_debug_data(req)) {
+		if (copy_to_user((void __user *)cmd->ddata_addr,
+				 &req->debug_data,
+				 sizeof(struct genwqe_debug_data)))
+			return -EFAULT;
+	}
+
+	/*
+	 * Higher values than 0x102 indicate completion with faults,
+	 * lower values than 0x102 indicate processing faults. Note
+	 * that DDCB might have been purged. E.g. Cntl+C.
+	 */
+	if (cmd->retc != DDCB_RETC_COMPLETE) {
+		/* This might happen e.g. flash read, and needs to be
+		   handled by the upper layer code. */
+		rc = -EBADMSG;	/* not processed/error retc */
+	}
+
+	return rc;
+
+ err_exit:
+	__genwqe_purge_ddcb(cd, req);
+
+	if (ddcb_requ_collect_debug_data(req)) {
+		if (copy_to_user((void __user *)cmd->ddata_addr,
+				 &req->debug_data,
+				 sizeof(struct genwqe_debug_data)))
+			return -EFAULT;
+	}
+	return rc;
+}
+
+/**
+ * genwqe_next_ddcb_ready() - Figure out if the next DDCB is already finished
+ *
+ * We use this as condition for our wait-queue code.
+ */
+static int genwqe_next_ddcb_ready(struct genwqe_dev *cd)
+{
+	unsigned long flags;
+	struct ddcb *pddcb;
+	struct ddcb_queue *queue = &cd->queue;
+
+	spin_lock_irqsave(&queue->ddcb_lock, flags);
+
+	if (queue_empty(queue)) { /* emtpy queue */
+		spin_unlock_irqrestore(&queue->ddcb_lock, flags);
+		return 0;
+	}
+
+	pddcb = &queue->ddcb_vaddr[queue->ddcb_act];
+	if (pddcb->icrc_hsi_shi_32 & DDCB_COMPLETED_BE32) { /* ddcb ready */
+		spin_unlock_irqrestore(&queue->ddcb_lock, flags);
+		return 1;
+	}
+
+	spin_unlock_irqrestore(&queue->ddcb_lock, flags);
+	return 0;
+}
+
+/**
+ * genwqe_ddcbs_in_flight() - Check how many DDCBs are in flight
+ *
+ * Keep track on the number of DDCBs which ware currently in the
+ * queue. This is needed for statistics as well as conditon if we want
+ * to wait or better do polling in case of no interrupts available.
+ */
+int genwqe_ddcbs_in_flight(struct genwqe_dev *cd)
+{
+	unsigned long flags;
+	int ddcbs_in_flight = 0;
+	struct ddcb_queue *queue = &cd->queue;
+
+	spin_lock_irqsave(&queue->ddcb_lock, flags);
+	ddcbs_in_flight += queue->ddcbs_in_flight;
+	spin_unlock_irqrestore(&queue->ddcb_lock, flags);
+
+	return ddcbs_in_flight;
+}
+
+static int setup_ddcb_queue(struct genwqe_dev *cd, struct ddcb_queue *queue)
+{
+	int rc, i;
+	struct ddcb *pddcb;
+	u64 val64;
+	unsigned int queue_size;
+	struct pci_dev *pci_dev = cd->pci_dev;
+
+	if (genwqe_ddcb_max < 2)
+		return -EINVAL;
+
+	queue_size = roundup(genwqe_ddcb_max * sizeof(struct ddcb), PAGE_SIZE);
+
+	queue->ddcbs_in_flight = 0;  /* statistics */
+	queue->ddcbs_max_in_flight = 0;
+	queue->ddcbs_completed = 0;
+	queue->busy = 0;
+
+	queue->ddcb_seq	  = 0x100; /* start sequence number */
+	queue->ddcb_max	  = genwqe_ddcb_max; /* module parameter */
+	queue->ddcb_vaddr = __genwqe_alloc_consistent(cd, queue_size,
+						&queue->ddcb_daddr);
+	if (queue->ddcb_vaddr == NULL) {
+		dev_err(&pci_dev->dev,
+			"[%s] **err: could not allocate DDCB **\n", __func__);
+		return -ENOMEM;
+	}
+	memset(queue->ddcb_vaddr, 0, queue_size);
+
+	queue->ddcb_req = kzalloc(sizeof(struct ddcb_requ *) *
+				  queue->ddcb_max, GFP_KERNEL);
+	if (!queue->ddcb_req) {
+		rc = -ENOMEM;
+		goto free_ddcbs;
+	}
+
+	queue->ddcb_waitqs = kzalloc(sizeof(wait_queue_head_t) *
+				     queue->ddcb_max, GFP_KERNEL);
+	if (!queue->ddcb_waitqs) {
+		rc = -ENOMEM;
+		goto free_requs;
+	}
+
+	for (i = 0; i < queue->ddcb_max; i++) {
+		pddcb = &queue->ddcb_vaddr[i];		     /* DDCBs */
+		pddcb->icrc_hsi_shi_32 = DDCB_COMPLETED_BE32;
+		pddcb->retc_16 = cpu_to_be16(0xfff);
+
+		queue->ddcb_req[i] = NULL;		     /* requests */
+		init_waitqueue_head(&queue->ddcb_waitqs[i]); /* waitqueues */
+	}
+
+	queue->ddcb_act  = 0;
+	queue->ddcb_next = 0;	/* queue is empty */
+
+	spin_lock_init(&queue->ddcb_lock);
+	init_waitqueue_head(&queue->ddcb_waitq);
+
+	val64 = ((u64)(queue->ddcb_max - 1) <<  8); /* lastptr */
+	__genwqe_writeq(cd, queue->IO_QUEUE_CONFIG,  0x07);  /* iCRC/vCRC */
+	__genwqe_writeq(cd, queue->IO_QUEUE_SEGMENT, queue->ddcb_daddr);
+	__genwqe_writeq(cd, queue->IO_QUEUE_INITSQN, queue->ddcb_seq);
+	__genwqe_writeq(cd, queue->IO_QUEUE_WRAP,    val64);
+	return 0;
+
+ free_requs:
+	kfree(queue->ddcb_req);
+	queue->ddcb_req = NULL;
+ free_ddcbs:
+	__genwqe_free_consistent(cd, queue_size, queue->ddcb_vaddr,
+				queue->ddcb_daddr);
+	queue->ddcb_vaddr = NULL;
+	queue->ddcb_daddr = 0ull;
+	return -ENODEV;
+
+}
+
+static int ddcb_queue_initialized(struct ddcb_queue *queue)
+{
+	return queue->ddcb_vaddr != NULL;
+}
+
+static void free_ddcb_queue(struct genwqe_dev *cd, struct ddcb_queue *queue)
+{
+	unsigned int queue_size;
+
+	queue_size = roundup(queue->ddcb_max * sizeof(struct ddcb), PAGE_SIZE);
+
+	kfree(queue->ddcb_req);
+	queue->ddcb_req = NULL;
+
+	if (queue->ddcb_vaddr) {
+		__genwqe_free_consistent(cd, queue_size, queue->ddcb_vaddr,
+					queue->ddcb_daddr);
+		queue->ddcb_vaddr = NULL;
+		queue->ddcb_daddr = 0ull;
+	}
+}
+
+static irqreturn_t genwqe_pf_isr(int irq, void *dev_id)
+{
+	u64 gfir;
+	struct genwqe_dev *cd = (struct genwqe_dev *)dev_id;
+	struct pci_dev *pci_dev = cd->pci_dev;
+
+	/*
+	 * In case of fatal FIR error the queue is stopped, such that
+	 * we can safely check it without risking anything.
+	 */
+	cd->irqs_processed++;
+	wake_up_interruptible(&cd->queue_waitq);
+
+	/*
+	 * Checking for errors before kicking the queue might be
+	 * safer, but slower for the good-case ... See above.
+	 */
+	gfir = __genwqe_readq(cd, IO_SLC_CFGREG_GFIR);
+	if ((gfir & GFIR_ERR_TRIGGER) != 0x0) {
+
+		wake_up_interruptible(&cd->health_waitq);
+
+		/*
+		 * By default GFIRs causes recovery actions. This
+		 * count is just for debug when recovery is masked.
+		 */
+		printk_ratelimited(KERN_ERR
+				   "%s %s: [%s] GFIR=%016llx\n",
+				   GENWQE_DEVNAME, dev_name(&pci_dev->dev),
+				   __func__, gfir);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t genwqe_vf_isr(int irq, void *dev_id)
+{
+	struct genwqe_dev *cd = (struct genwqe_dev *)dev_id;
+
+	cd->irqs_processed++;
+	wake_up_interruptible(&cd->queue_waitq);
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * genwqe_card_thread() - Work thread for the DDCB queue
+ *
+ * The idea is to check if there are DDCBs in processing. If there are
+ * some finished DDCBs, we process them and wakeup the
+ * requestors. Otherwise we give other processes time using
+ * cond_resched().
+ */
+static int genwqe_card_thread(void *data)
+{
+	int should_stop = 0, rc = 0;
+	struct genwqe_dev *cd = (struct genwqe_dev *)data;
+
+	while (!kthread_should_stop()) {
+
+		genwqe_check_ddcb_queue(cd, &cd->queue);
+
+		if (genwqe_polling_enabled) {
+			rc = wait_event_interruptible_timeout(
+				cd->queue_waitq,
+				genwqe_ddcbs_in_flight(cd) ||
+				(should_stop = kthread_should_stop()), 1);
+		} else {
+			rc = wait_event_interruptible_timeout(
+				cd->queue_waitq,
+				genwqe_next_ddcb_ready(cd) ||
+				(should_stop = kthread_should_stop()), HZ);
+		}
+		if (should_stop)
+			break;
+
+		/*
+		 * Avoid soft lockups on heavy loads; we do not want
+		 * to disable our interrupts.
+		 */
+		cond_resched();
+	}
+	return 0;
+}
+
+/**
+ * genwqe_setup_service_layer() - Setup DDCB queue
+ * @cd:         pointer to genwqe device descriptor
+ *
+ * Allocate DDCBs. Configure Service Layer Controller (SLC).
+ *
+ * Return: 0 success
+ */
+int genwqe_setup_service_layer(struct genwqe_dev *cd)
+{
+	int rc;
+	struct ddcb_queue *queue;
+	struct pci_dev *pci_dev = cd->pci_dev;
+
+	if (genwqe_is_privileged(cd)) {
+		rc = genwqe_card_reset(cd);
+		if (rc < 0) {
+			dev_err(&pci_dev->dev,
+				"[%s] err: reset failed.\n", __func__);
+			return rc;
+		}
+		genwqe_read_softreset(cd);
+	}
+
+	queue = &cd->queue;
+	queue->IO_QUEUE_CONFIG  = IO_SLC_QUEUE_CONFIG;
+	queue->IO_QUEUE_STATUS  = IO_SLC_QUEUE_STATUS;
+	queue->IO_QUEUE_SEGMENT = IO_SLC_QUEUE_SEGMENT;
+	queue->IO_QUEUE_INITSQN = IO_SLC_QUEUE_INITSQN;
+	queue->IO_QUEUE_OFFSET  = IO_SLC_QUEUE_OFFSET;
+	queue->IO_QUEUE_WRAP    = IO_SLC_QUEUE_WRAP;
+	queue->IO_QUEUE_WTIME   = IO_SLC_QUEUE_WTIME;
+	queue->IO_QUEUE_ERRCNTS = IO_SLC_QUEUE_ERRCNTS;
+	queue->IO_QUEUE_LRW     = IO_SLC_QUEUE_LRW;
+
+	rc = setup_ddcb_queue(cd, queue);
+	if (rc != 0) {
+		rc = -ENODEV;
+		goto err_out;
+	}
+
+	init_waitqueue_head(&cd->queue_waitq);
+	cd->card_thread = kthread_run(genwqe_card_thread, cd,
+				      GENWQE_DEVNAME "%d_thread",
+				      cd->card_idx);
+	if (IS_ERR(cd->card_thread)) {
+		rc = PTR_ERR(cd->card_thread);
+		cd->card_thread = NULL;
+		goto stop_free_queue;
+	}
+
+	rc = genwqe_set_interrupt_capability(cd, GENWQE_MSI_IRQS);
+	if (rc > 0)
+		rc = genwqe_set_interrupt_capability(cd, rc);
+	if (rc != 0) {
+		rc = -ENODEV;
+		goto stop_kthread;
+	}
+
+	/*
+	 * We must have all wait-queues initialized when we enable the
+	 * interrupts. Otherwise we might crash if we get an early
+	 * irq.
+	 */
+	init_waitqueue_head(&cd->health_waitq);
+
+	if (genwqe_is_privileged(cd)) {
+		rc = request_irq(pci_dev->irq, genwqe_pf_isr, IRQF_SHARED,
+				 GENWQE_DEVNAME, cd);
+	} else {
+		rc = request_irq(pci_dev->irq, genwqe_vf_isr, IRQF_SHARED,
+				 GENWQE_DEVNAME, cd);
+	}
+	if (rc < 0) {
+		dev_err(&pci_dev->dev, "irq %d not free.\n", pci_dev->irq);
+		goto stop_irq_cap;
+	}
+
+	cd->card_state = GENWQE_CARD_USED;
+	return 0;
+
+ stop_irq_cap:
+	genwqe_reset_interrupt_capability(cd);
+ stop_kthread:
+	kthread_stop(cd->card_thread);
+	cd->card_thread = NULL;
+ stop_free_queue:
+	free_ddcb_queue(cd, queue);
+ err_out:
+	return rc;
+}
+
+/**
+ * queue_wake_up_all() - Handles fatal error case
+ *
+ * The PCI device got unusable and we have to stop all pending
+ * requests as fast as we can. The code after this must purge the
+ * DDCBs in question and ensure that all mappings are freed.
+ */
+static int queue_wake_up_all(struct genwqe_dev *cd)
+{
+	unsigned int i;
+	unsigned long flags;
+	struct ddcb_queue *queue = &cd->queue;
+
+	spin_lock_irqsave(&queue->ddcb_lock, flags);
+
+	for (i = 0; i < queue->ddcb_max; i++)
+		wake_up_interruptible(&queue->ddcb_waitqs[queue->ddcb_act]);
+
+	spin_unlock_irqrestore(&queue->ddcb_lock, flags);
+
+	return 0;
+}
+
+/**
+ * genwqe_finish_queue() - Remove any genwqe devices and user-interfaces
+ *
+ * Relies on the pre-condition that there are no users of the card
+ * device anymore e.g. with open file-descriptors.
+ *
+ * This function must be robust enough to be called twice.
+ */
+int genwqe_finish_queue(struct genwqe_dev *cd)
+{
+	int i, rc, in_flight;
+	int waitmax = genwqe_ddcb_software_timeout;
+	struct pci_dev *pci_dev = cd->pci_dev;
+	struct ddcb_queue *queue = &cd->queue;
+
+	if (!ddcb_queue_initialized(queue))
+		return 0;
+
+	/* Do not wipe out the error state. */
+	if (cd->card_state == GENWQE_CARD_USED)
+		cd->card_state = GENWQE_CARD_UNUSED;
+
+	/* Wake up all requests in the DDCB queue such that they
+	   should be removed nicely. */
+	queue_wake_up_all(cd);
+
+	/* We must wait to get rid of the DDCBs in flight */
+	for (i = 0; i < waitmax; i++) {
+		in_flight = genwqe_ddcbs_in_flight(cd);
+
+		if (in_flight == 0)
+			break;
+
+		dev_dbg(&pci_dev->dev,
+			"  DEBUG [%d/%d] waiting for queue to get empty: "
+			"%d requests!\n", i, waitmax, in_flight);
+
+		/*
+		 * Severe severe error situation: The card itself has
+		 * 16 DDCB queues, each queue has e.g. 32 entries,
+		 * each DDBC has a hardware timeout of currently 250
+		 * msec but the PFs have a hardware timeout of 8 sec
+		 * ... so I take something large.
+		 */
+		msleep(1000);
+	}
+	if (i == waitmax) {
+		dev_err(&pci_dev->dev, "  [%s] err: queue is not empty!!\n",
+			__func__);
+		rc = -EIO;
+	}
+	return rc;
+}
+
+/**
+ * genwqe_release_service_layer() - Shutdown DDCB queue
+ * @cd:       genwqe device descriptor
+ *
+ * This function must be robust enough to be called twice.
+ */
+int genwqe_release_service_layer(struct genwqe_dev *cd)
+{
+	struct pci_dev *pci_dev = cd->pci_dev;
+
+	if (!ddcb_queue_initialized(&cd->queue))
+		return 1;
+
+	free_irq(pci_dev->irq, cd);
+	genwqe_reset_interrupt_capability(cd);
+
+	if (cd->card_thread != NULL) {
+		kthread_stop(cd->card_thread);
+		cd->card_thread = NULL;
+	}
+
+	free_ddcb_queue(cd, &cd->queue);
+	return 0;
+}