Initial import

1 files changed, 1411 insertions, 0 deletions

diff --git a/drivers/misc/genwqe/card_ddcb.c b/drivers/misc/genwqe/card_ddcb.c
new file mode 100644
index 000000000..6d51e5f08
--- /dev/null
+++ b/drivers/misc/genwqe/card_ddcb.c
@@ -0,0 +1,1411 @@
+/**
+ * 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@gmx.net>
+ * 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_base.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;
+	__be32 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);
+
+		wmb();		/* need to ensure write ordering */
+		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;
+
+	wmb();			/* need to ensure write ordering */
+	__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 */
+
+		wmb();  /*  Add sync to decouple prev. read operations */
+
+		/* 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 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, and
+                   processes on the busy queue */
+		wake_up_interruptible(&queue->ddcb_waitqs[queue->ddcb_act]);
+		wake_up_interruptible(&queue->busy_waitq);
+
+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;
+	u64 queue_status;
+	__be32 icrc_hsi_shi = 0x0000;
+	__be32 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_VERSION);
+	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
+ * @f_flags:    file mode: blocking, non-blocking
+ *
+ * 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,
+			  unsigned int f_flags)
+{
+	struct ddcb *pddcb;
+	unsigned long flags;
+	struct ddcb_queue *queue;
+	struct pci_dev *pci_dev = cd->pci_dev;
+	u16 icrc;
+
+ retry:
+	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) {
+		int rc;
+
+		spin_unlock_irqrestore(&queue->ddcb_lock, flags);
+
+		if (f_flags & O_NONBLOCK) {
+			queue->return_on_busy++;
+			return -EBUSY;
+		}
+
+		queue->wait_on_busy++;
+		rc = wait_event_interruptible(queue->busy_waitq,
+					      queue_free_ddcbs(queue) != 0);
+		dev_dbg(&pci_dev->dev, "[%s] waiting for free DDCB: rc=%d\n",
+			__func__, rc);
+		if (rc == -ERESTARTSYS)
+			return rc;  /* interrupted by a signal */
+
+		goto retry;
+	}
+
+	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 = cpu_to_be64(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
+ * @f_flags:    file mode: blocking, non-blocking
+ */
+int __genwqe_execute_raw_ddcb(struct genwqe_dev *cd,
+			      struct genwqe_ddcb_cmd *cmd,
+			      unsigned int f_flags)
+{
+	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, f_flags);
+	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((struct genwqe_debug_data __user *)
+				 (unsigned long)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((struct genwqe_debug_data __user *)
+				 (unsigned long)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->return_on_busy = 0;
+	queue->wait_on_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->busy_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) &&
+	    !pci_channel_offline(pci_dev)) {
+
+		if (cd->use_platform_recovery) {
+			/*
+			 * Since we use raw accessors, EEH errors won't be
+			 * detected by the platform until we do a non-raw
+			 * MMIO or config space read
+			 */
+			readq(cd->mmio + IO_SLC_CFGREG_GFIR);
+
+			/* Don't do anything if the PCI channel is frozen */
+			if (pci_channel_offline(pci_dev))
+				goto exit;
+		}
+
+		wake_up_interruptible(&cd->health_waitq);
+
+		/*
+		 * By default GFIRs causes recovery actions. This
+		 * count is just for debug when recovery is masked.
+		 */
+		dev_err_ratelimited(&pci_dev->dev,
+				    "[%s] GFIR=%016llx\n",
+				    __func__, gfir);
+	}
+
+ exit:
+	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)
+		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]);
+
+	wake_up_interruptible(&queue->busy_waitq);
+	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 = 0, 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;
+}