Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2507 insertions, 0 deletions

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
new file mode 100644
index 000000000..9532108d2
--- /dev/null
+++ b/drivers/ntb/ntb_transport.c
@@ -0,0 +1,2507 @@
+/*
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ *   redistributing this file, you may do so under either license.
+ *
+ *   GPL LICENSE SUMMARY
+ *
+ *   Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *   Copyright (C) 2015 EMC Corporation. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of version 2 of the GNU General Public License as
+ *   published by the Free Software Foundation.
+ *
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *   Copyright (C) 2015 EMC Corporation. All Rights Reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copy
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * PCIe NTB Transport Linux driver
+ *
+ * Contact Information:
+ * Jon Mason <jon.mason@intel.com>
+ */
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include "linux/ntb.h"
+#include "linux/ntb_transport.h"
+
+#define NTB_TRANSPORT_VERSION	4
+#define NTB_TRANSPORT_VER	"4"
+#define NTB_TRANSPORT_NAME	"ntb_transport"
+#define NTB_TRANSPORT_DESC	"Software Queue-Pair Transport over NTB"
+#define NTB_TRANSPORT_MIN_SPADS (MW0_SZ_HIGH + 2)
+
+MODULE_DESCRIPTION(NTB_TRANSPORT_DESC);
+MODULE_VERSION(NTB_TRANSPORT_VER);
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Intel Corporation");
+
+static unsigned long max_mw_size;
+module_param(max_mw_size, ulong, 0644);
+MODULE_PARM_DESC(max_mw_size, "Limit size of large memory windows");
+
+static unsigned int transport_mtu = 0x10000;
+module_param(transport_mtu, uint, 0644);
+MODULE_PARM_DESC(transport_mtu, "Maximum size of NTB transport packets");
+
+static unsigned char max_num_clients;
+module_param(max_num_clients, byte, 0644);
+MODULE_PARM_DESC(max_num_clients, "Maximum number of NTB transport clients");
+
+static unsigned int copy_bytes = 1024;
+module_param(copy_bytes, uint, 0644);
+MODULE_PARM_DESC(copy_bytes, "Threshold under which NTB will use the CPU to copy instead of DMA");
+
+static bool use_dma;
+module_param(use_dma, bool, 0644);
+MODULE_PARM_DESC(use_dma, "Use DMA engine to perform large data copy");
+
+static bool use_msi;
+#ifdef CONFIG_NTB_MSI
+module_param(use_msi, bool, 0644);
+MODULE_PARM_DESC(use_msi, "Use MSI interrupts instead of doorbells");
+#endif
+
+static struct dentry *nt_debugfs_dir;
+
+/* Only two-ports NTB devices are supported */
+#define PIDX		NTB_DEF_PEER_IDX
+
+struct ntb_queue_entry {
+	/* ntb_queue list reference */
+	struct list_head entry;
+	/* pointers to data to be transferred */
+	void *cb_data;
+	void *buf;
+	unsigned int len;
+	unsigned int flags;
+	int retries;
+	int errors;
+	unsigned int tx_index;
+	unsigned int rx_index;
+
+	struct ntb_transport_qp *qp;
+	union {
+		struct ntb_payload_header __iomem *tx_hdr;
+		struct ntb_payload_header *rx_hdr;
+	};
+};
+
+struct ntb_rx_info {
+	unsigned int entry;
+};
+
+struct ntb_transport_qp {
+	struct ntb_transport_ctx *transport;
+	struct ntb_dev *ndev;
+	void *cb_data;
+	struct dma_chan *tx_dma_chan;
+	struct dma_chan *rx_dma_chan;
+
+	bool client_ready;
+	bool link_is_up;
+	bool active;
+
+	u8 qp_num;	/* Only 64 QP's are allowed.  0-63 */
+	u64 qp_bit;
+
+	struct ntb_rx_info __iomem *rx_info;
+	struct ntb_rx_info *remote_rx_info;
+
+	void (*tx_handler)(struct ntb_transport_qp *qp, void *qp_data,
+			   void *data, int len);
+	struct list_head tx_free_q;
+	spinlock_t ntb_tx_free_q_lock;
+	void __iomem *tx_mw;
+	phys_addr_t tx_mw_phys;
+	size_t tx_mw_size;
+	dma_addr_t tx_mw_dma_addr;
+	unsigned int tx_index;
+	unsigned int tx_max_entry;
+	unsigned int tx_max_frame;
+
+	void (*rx_handler)(struct ntb_transport_qp *qp, void *qp_data,
+			   void *data, int len);
+	struct list_head rx_post_q;
+	struct list_head rx_pend_q;
+	struct list_head rx_free_q;
+	/* ntb_rx_q_lock: synchronize access to rx_XXXX_q */
+	spinlock_t ntb_rx_q_lock;
+	void *rx_buff;
+	unsigned int rx_index;
+	unsigned int rx_max_entry;
+	unsigned int rx_max_frame;
+	unsigned int rx_alloc_entry;
+	dma_cookie_t last_cookie;
+	struct tasklet_struct rxc_db_work;
+
+	void (*event_handler)(void *data, int status);
+	struct delayed_work link_work;
+	struct work_struct link_cleanup;
+
+	struct dentry *debugfs_dir;
+	struct dentry *debugfs_stats;
+
+	/* Stats */
+	u64 rx_bytes;
+	u64 rx_pkts;
+	u64 rx_ring_empty;
+	u64 rx_err_no_buf;
+	u64 rx_err_oflow;
+	u64 rx_err_ver;
+	u64 rx_memcpy;
+	u64 rx_async;
+	u64 tx_bytes;
+	u64 tx_pkts;
+	u64 tx_ring_full;
+	u64 tx_err_no_buf;
+	u64 tx_memcpy;
+	u64 tx_async;
+
+	bool use_msi;
+	int msi_irq;
+	struct ntb_msi_desc msi_desc;
+	struct ntb_msi_desc peer_msi_desc;
+};
+
+struct ntb_transport_mw {
+	phys_addr_t phys_addr;
+	resource_size_t phys_size;
+	void __iomem *vbase;
+	size_t xlat_size;
+	size_t buff_size;
+	size_t alloc_size;
+	void *alloc_addr;
+	void *virt_addr;
+	dma_addr_t dma_addr;
+};
+
+struct ntb_transport_client_dev {
+	struct list_head entry;
+	struct ntb_transport_ctx *nt;
+	struct device dev;
+};
+
+struct ntb_transport_ctx {
+	struct list_head entry;
+	struct list_head client_devs;
+
+	struct ntb_dev *ndev;
+
+	struct ntb_transport_mw *mw_vec;
+	struct ntb_transport_qp *qp_vec;
+	unsigned int mw_count;
+	unsigned int qp_count;
+	u64 qp_bitmap;
+	u64 qp_bitmap_free;
+
+	bool use_msi;
+	unsigned int msi_spad_offset;
+	u64 msi_db_mask;
+
+	bool link_is_up;
+	struct delayed_work link_work;
+	struct work_struct link_cleanup;
+
+	struct dentry *debugfs_node_dir;
+};
+
+enum {
+	DESC_DONE_FLAG = BIT(0),
+	LINK_DOWN_FLAG = BIT(1),
+};
+
+struct ntb_payload_header {
+	unsigned int ver;
+	unsigned int len;
+	unsigned int flags;
+};
+
+enum {
+	VERSION = 0,
+	QP_LINKS,
+	NUM_QPS,
+	NUM_MWS,
+	MW0_SZ_HIGH,
+	MW0_SZ_LOW,
+};
+
+#define dev_client_dev(__dev) \
+	container_of((__dev), struct ntb_transport_client_dev, dev)
+
+#define drv_client(__drv) \
+	container_of((__drv), struct ntb_transport_client, driver)
+
+#define QP_TO_MW(nt, qp)	((qp) % nt->mw_count)
+#define NTB_QP_DEF_NUM_ENTRIES	100
+#define NTB_LINK_DOWN_TIMEOUT	10
+
+static void ntb_transport_rxc_db(unsigned long data);
+static const struct ntb_ctx_ops ntb_transport_ops;
+static struct ntb_client ntb_transport_client;
+static int ntb_async_tx_submit(struct ntb_transport_qp *qp,
+			       struct ntb_queue_entry *entry);
+static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset);
+static int ntb_async_rx_submit(struct ntb_queue_entry *entry, void *offset);
+static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset);
+
+
+static int ntb_transport_bus_match(struct device *dev,
+				   struct device_driver *drv)
+{
+	return !strncmp(dev_name(dev), drv->name, strlen(drv->name));
+}
+
+static int ntb_transport_bus_probe(struct device *dev)
+{
+	const struct ntb_transport_client *client;
+	int rc;
+
+	get_device(dev);
+
+	client = drv_client(dev->driver);
+	rc = client->probe(dev);
+	if (rc)
+		put_device(dev);
+
+	return rc;
+}
+
+static void ntb_transport_bus_remove(struct device *dev)
+{
+	const struct ntb_transport_client *client;
+
+	client = drv_client(dev->driver);
+	client->remove(dev);
+
+	put_device(dev);
+}
+
+static struct bus_type ntb_transport_bus = {
+	.name = "ntb_transport",
+	.match = ntb_transport_bus_match,
+	.probe = ntb_transport_bus_probe,
+	.remove = ntb_transport_bus_remove,
+};
+
+static LIST_HEAD(ntb_transport_list);
+
+static int ntb_bus_init(struct ntb_transport_ctx *nt)
+{
+	list_add_tail(&nt->entry, &ntb_transport_list);
+	return 0;
+}
+
+static void ntb_bus_remove(struct ntb_transport_ctx *nt)
+{
+	struct ntb_transport_client_dev *client_dev, *cd;
+
+	list_for_each_entry_safe(client_dev, cd, &nt->client_devs, entry) {
+		dev_err(client_dev->dev.parent, "%s still attached to bus, removing\n",
+			dev_name(&client_dev->dev));
+		list_del(&client_dev->entry);
+		device_unregister(&client_dev->dev);
+	}
+
+	list_del(&nt->entry);
+}
+
+static void ntb_transport_client_release(struct device *dev)
+{
+	struct ntb_transport_client_dev *client_dev;
+
+	client_dev = dev_client_dev(dev);
+	kfree(client_dev);
+}
+
+/**
+ * ntb_transport_unregister_client_dev - Unregister NTB client device
+ * @device_name: Name of NTB client device
+ *
+ * Unregister an NTB client device with the NTB transport layer
+ */
+void ntb_transport_unregister_client_dev(char *device_name)
+{
+	struct ntb_transport_client_dev *client, *cd;
+	struct ntb_transport_ctx *nt;
+
+	list_for_each_entry(nt, &ntb_transport_list, entry)
+		list_for_each_entry_safe(client, cd, &nt->client_devs, entry)
+			if (!strncmp(dev_name(&client->dev), device_name,
+				     strlen(device_name))) {
+				list_del(&client->entry);
+				device_unregister(&client->dev);
+			}
+}
+EXPORT_SYMBOL_GPL(ntb_transport_unregister_client_dev);
+
+/**
+ * ntb_transport_register_client_dev - Register NTB client device
+ * @device_name: Name of NTB client device
+ *
+ * Register an NTB client device with the NTB transport layer
+ */
+int ntb_transport_register_client_dev(char *device_name)
+{
+	struct ntb_transport_client_dev *client_dev;
+	struct ntb_transport_ctx *nt;
+	int node;
+	int rc, i = 0;
+
+	if (list_empty(&ntb_transport_list))
+		return -ENODEV;
+
+	list_for_each_entry(nt, &ntb_transport_list, entry) {
+		struct device *dev;
+
+		node = dev_to_node(&nt->ndev->dev);
+
+		client_dev = kzalloc_node(sizeof(*client_dev),
+					  GFP_KERNEL, node);
+		if (!client_dev) {
+			rc = -ENOMEM;
+			goto err;
+		}
+
+		dev = &client_dev->dev;
+
+		/* setup and register client devices */
+		dev_set_name(dev, "%s%d", device_name, i);
+		dev->bus = &ntb_transport_bus;
+		dev->release = ntb_transport_client_release;
+		dev->parent = &nt->ndev->dev;
+
+		rc = device_register(dev);
+		if (rc) {
+			put_device(dev);
+			goto err;
+		}
+
+		list_add_tail(&client_dev->entry, &nt->client_devs);
+		i++;
+	}
+
+	return 0;
+
+err:
+	ntb_transport_unregister_client_dev(device_name);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_register_client_dev);
+
+/**
+ * ntb_transport_register_client - Register NTB client driver
+ * @drv: NTB client driver to be registered
+ *
+ * Register an NTB client driver with the NTB transport layer
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_transport_register_client(struct ntb_transport_client *drv)
+{
+	drv->driver.bus = &ntb_transport_bus;
+
+	if (list_empty(&ntb_transport_list))
+		return -ENODEV;
+
+	return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(ntb_transport_register_client);
+
+/**
+ * ntb_transport_unregister_client - Unregister NTB client driver
+ * @drv: NTB client driver to be unregistered
+ *
+ * Unregister an NTB client driver with the NTB transport layer
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+void ntb_transport_unregister_client(struct ntb_transport_client *drv)
+{
+	driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(ntb_transport_unregister_client);
+
+static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
+			    loff_t *offp)
+{
+	struct ntb_transport_qp *qp;
+	char *buf;
+	ssize_t ret, out_offset, out_count;
+
+	qp = filp->private_data;
+
+	if (!qp || !qp->link_is_up)
+		return 0;
+
+	out_count = 1000;
+
+	buf = kmalloc(out_count, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	out_offset = 0;
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "\nNTB QP stats:\n\n");
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "rx_bytes - \t%llu\n", qp->rx_bytes);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "rx_pkts - \t%llu\n", qp->rx_pkts);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "rx_memcpy - \t%llu\n", qp->rx_memcpy);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "rx_async - \t%llu\n", qp->rx_async);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "rx_ring_empty - %llu\n", qp->rx_ring_empty);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "rx_err_no_buf - %llu\n", qp->rx_err_no_buf);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "rx_err_oflow - \t%llu\n", qp->rx_err_oflow);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "rx_err_ver - \t%llu\n", qp->rx_err_ver);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "rx_buff - \t0x%p\n", qp->rx_buff);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "rx_index - \t%u\n", qp->rx_index);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "rx_max_entry - \t%u\n", qp->rx_max_entry);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "rx_alloc_entry - \t%u\n\n", qp->rx_alloc_entry);
+
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "tx_bytes - \t%llu\n", qp->tx_bytes);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "tx_pkts - \t%llu\n", qp->tx_pkts);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "tx_memcpy - \t%llu\n", qp->tx_memcpy);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "tx_async - \t%llu\n", qp->tx_async);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "tx_ring_full - \t%llu\n", qp->tx_ring_full);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "tx_err_no_buf - %llu\n", qp->tx_err_no_buf);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "tx_mw - \t0x%p\n", qp->tx_mw);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "tx_index (H) - \t%u\n", qp->tx_index);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "RRI (T) - \t%u\n",
+			       qp->remote_rx_info->entry);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "tx_max_entry - \t%u\n", qp->tx_max_entry);
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "free tx - \t%u\n",
+			       ntb_transport_tx_free_entry(qp));
+
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "\n");
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "Using TX DMA - \t%s\n",
+			       qp->tx_dma_chan ? "Yes" : "No");
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "Using RX DMA - \t%s\n",
+			       qp->rx_dma_chan ? "Yes" : "No");
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "QP Link - \t%s\n",
+			       qp->link_is_up ? "Up" : "Down");
+	out_offset += scnprintf(buf + out_offset, out_count - out_offset,
+			       "\n");
+
+	if (out_offset > out_count)
+		out_offset = out_count;
+
+	ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
+	kfree(buf);
+	return ret;
+}
+
+static const struct file_operations ntb_qp_debugfs_stats = {
+	.owner = THIS_MODULE,
+	.open = simple_open,
+	.read = debugfs_read,
+};
+
+static void ntb_list_add(spinlock_t *lock, struct list_head *entry,
+			 struct list_head *list)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(lock, flags);
+	list_add_tail(entry, list);
+	spin_unlock_irqrestore(lock, flags);
+}
+
+static struct ntb_queue_entry *ntb_list_rm(spinlock_t *lock,
+					   struct list_head *list)
+{
+	struct ntb_queue_entry *entry;
+	unsigned long flags;
+
+	spin_lock_irqsave(lock, flags);
+	if (list_empty(list)) {
+		entry = NULL;
+		goto out;
+	}
+	entry = list_first_entry(list, struct ntb_queue_entry, entry);
+	list_del(&entry->entry);
+
+out:
+	spin_unlock_irqrestore(lock, flags);
+
+	return entry;
+}
+
+static struct ntb_queue_entry *ntb_list_mv(spinlock_t *lock,
+					   struct list_head *list,
+					   struct list_head *to_list)
+{
+	struct ntb_queue_entry *entry;
+	unsigned long flags;
+
+	spin_lock_irqsave(lock, flags);
+
+	if (list_empty(list)) {
+		entry = NULL;
+	} else {
+		entry = list_first_entry(list, struct ntb_queue_entry, entry);
+		list_move_tail(&entry->entry, to_list);
+	}
+
+	spin_unlock_irqrestore(lock, flags);
+
+	return entry;
+}
+
+static int ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt,
+				     unsigned int qp_num)
+{
+	struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
+	struct ntb_transport_mw *mw;
+	struct ntb_dev *ndev = nt->ndev;
+	struct ntb_queue_entry *entry;
+	unsigned int rx_size, num_qps_mw;
+	unsigned int mw_num, mw_count, qp_count;
+	unsigned int i;
+	int node;
+
+	mw_count = nt->mw_count;
+	qp_count = nt->qp_count;
+
+	mw_num = QP_TO_MW(nt, qp_num);
+	mw = &nt->mw_vec[mw_num];
+
+	if (!mw->virt_addr)
+		return -ENOMEM;
+
+	if (mw_num < qp_count % mw_count)
+		num_qps_mw = qp_count / mw_count + 1;
+	else
+		num_qps_mw = qp_count / mw_count;
+
+	rx_size = (unsigned int)mw->xlat_size / num_qps_mw;
+	qp->rx_buff = mw->virt_addr + rx_size * (qp_num / mw_count);
+	rx_size -= sizeof(struct ntb_rx_info);
+
+	qp->remote_rx_info = qp->rx_buff + rx_size;
+
+	/* Due to housekeeping, there must be atleast 2 buffs */
+	qp->rx_max_frame = min(transport_mtu, rx_size / 2);
+	qp->rx_max_entry = rx_size / qp->rx_max_frame;
+	qp->rx_index = 0;
+
+	/*
+	 * Checking to see if we have more entries than the default.
+	 * We should add additional entries if that is the case so we
+	 * can be in sync with the transport frames.
+	 */
+	node = dev_to_node(&ndev->dev);
+	for (i = qp->rx_alloc_entry; i < qp->rx_max_entry; i++) {
+		entry = kzalloc_node(sizeof(*entry), GFP_KERNEL, node);
+		if (!entry)
+			return -ENOMEM;
+
+		entry->qp = qp;
+		ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry,
+			     &qp->rx_free_q);
+		qp->rx_alloc_entry++;
+	}
+
+	qp->remote_rx_info->entry = qp->rx_max_entry - 1;
+
+	/* setup the hdr offsets with 0's */
+	for (i = 0; i < qp->rx_max_entry; i++) {
+		void *offset = (qp->rx_buff + qp->rx_max_frame * (i + 1) -
+				sizeof(struct ntb_payload_header));
+		memset(offset, 0, sizeof(struct ntb_payload_header));
+	}
+
+	qp->rx_pkts = 0;
+	qp->tx_pkts = 0;
+	qp->tx_index = 0;
+
+	return 0;
+}
+
+static irqreturn_t ntb_transport_isr(int irq, void *dev)
+{
+	struct ntb_transport_qp *qp = dev;
+
+	tasklet_schedule(&qp->rxc_db_work);
+
+	return IRQ_HANDLED;
+}
+
+static void ntb_transport_setup_qp_peer_msi(struct ntb_transport_ctx *nt,
+					    unsigned int qp_num)
+{
+	struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
+	int spad = qp_num * 2 + nt->msi_spad_offset;
+
+	if (!nt->use_msi)
+		return;
+
+	if (spad >= ntb_spad_count(nt->ndev))
+		return;
+
+	qp->peer_msi_desc.addr_offset =
+		ntb_peer_spad_read(qp->ndev, PIDX, spad);
+	qp->peer_msi_desc.data =
+		ntb_peer_spad_read(qp->ndev, PIDX, spad + 1);
+
+	dev_dbg(&qp->ndev->pdev->dev, "QP%d Peer MSI addr=%x data=%x\n",
+		qp_num, qp->peer_msi_desc.addr_offset, qp->peer_msi_desc.data);
+
+	if (qp->peer_msi_desc.addr_offset) {
+		qp->use_msi = true;
+		dev_info(&qp->ndev->pdev->dev,
+			 "Using MSI interrupts for QP%d\n", qp_num);
+	}
+}
+
+static void ntb_transport_setup_qp_msi(struct ntb_transport_ctx *nt,
+				       unsigned int qp_num)
+{
+	struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
+	int spad = qp_num * 2 + nt->msi_spad_offset;
+	int rc;
+
+	if (!nt->use_msi)
+		return;
+
+	if (spad >= ntb_spad_count(nt->ndev)) {
+		dev_warn_once(&qp->ndev->pdev->dev,
+			      "Not enough SPADS to use MSI interrupts\n");
+		return;
+	}
+
+	ntb_spad_write(qp->ndev, spad, 0);
+	ntb_spad_write(qp->ndev, spad + 1, 0);
+
+	if (!qp->msi_irq) {
+		qp->msi_irq = ntbm_msi_request_irq(qp->ndev, ntb_transport_isr,
+						   KBUILD_MODNAME, qp,
+						   &qp->msi_desc);
+		if (qp->msi_irq < 0) {
+			dev_warn(&qp->ndev->pdev->dev,
+				 "Unable to allocate MSI interrupt for qp%d\n",
+				 qp_num);
+			return;
+		}
+	}
+
+	rc = ntb_spad_write(qp->ndev, spad, qp->msi_desc.addr_offset);
+	if (rc)
+		goto err_free_interrupt;
+
+	rc = ntb_spad_write(qp->ndev, spad + 1, qp->msi_desc.data);
+	if (rc)
+		goto err_free_interrupt;
+
+	dev_dbg(&qp->ndev->pdev->dev, "QP%d MSI %d addr=%x data=%x\n",
+		qp_num, qp->msi_irq, qp->msi_desc.addr_offset,
+		qp->msi_desc.data);
+
+	return;
+
+err_free_interrupt:
+	devm_free_irq(&nt->ndev->dev, qp->msi_irq, qp);
+}
+
+static void ntb_transport_msi_peer_desc_changed(struct ntb_transport_ctx *nt)
+{
+	int i;
+
+	dev_dbg(&nt->ndev->pdev->dev, "Peer MSI descriptors changed");
+
+	for (i = 0; i < nt->qp_count; i++)
+		ntb_transport_setup_qp_peer_msi(nt, i);
+}
+
+static void ntb_transport_msi_desc_changed(void *data)
+{
+	struct ntb_transport_ctx *nt = data;
+	int i;
+
+	dev_dbg(&nt->ndev->pdev->dev, "MSI descriptors changed");
+
+	for (i = 0; i < nt->qp_count; i++)
+		ntb_transport_setup_qp_msi(nt, i);
+
+	ntb_peer_db_set(nt->ndev, nt->msi_db_mask);
+}
+
+static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
+{
+	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
+	struct pci_dev *pdev = nt->ndev->pdev;
+
+	if (!mw->virt_addr)
+		return;
+
+	ntb_mw_clear_trans(nt->ndev, PIDX, num_mw);
+	dma_free_coherent(&pdev->dev, mw->alloc_size,
+			  mw->alloc_addr, mw->dma_addr);
+	mw->xlat_size = 0;
+	mw->buff_size = 0;
+	mw->alloc_size = 0;
+	mw->alloc_addr = NULL;
+	mw->virt_addr = NULL;
+}
+
+static int ntb_alloc_mw_buffer(struct ntb_transport_mw *mw,
+			       struct device *dma_dev, size_t align)
+{
+	dma_addr_t dma_addr;
+	void *alloc_addr, *virt_addr;
+	int rc;
+
+	alloc_addr = dma_alloc_coherent(dma_dev, mw->alloc_size,
+					&dma_addr, GFP_KERNEL);
+	if (!alloc_addr) {
+		dev_err(dma_dev, "Unable to alloc MW buff of size %zu\n",
+			mw->alloc_size);
+		return -ENOMEM;
+	}
+	virt_addr = alloc_addr;
+
+	/*
+	 * we must ensure that the memory address allocated is BAR size
+	 * aligned in order for the XLAT register to take the value. This
+	 * is a requirement of the hardware. It is recommended to setup CMA
+	 * for BAR sizes equal or greater than 4MB.
+	 */
+	if (!IS_ALIGNED(dma_addr, align)) {
+		if (mw->alloc_size > mw->buff_size) {
+			virt_addr = PTR_ALIGN(alloc_addr, align);
+			dma_addr = ALIGN(dma_addr, align);
+		} else {
+			rc = -ENOMEM;
+			goto err;
+		}
+	}
+
+	mw->alloc_addr = alloc_addr;
+	mw->virt_addr = virt_addr;
+	mw->dma_addr = dma_addr;
+
+	return 0;
+
+err:
+	dma_free_coherent(dma_dev, mw->alloc_size, alloc_addr, dma_addr);
+
+	return rc;
+}
+
+static int ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw,
+		      resource_size_t size)
+{
+	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
+	struct pci_dev *pdev = nt->ndev->pdev;
+	size_t xlat_size, buff_size;
+	resource_size_t xlat_align;
+	resource_size_t xlat_align_size;
+	int rc;
+
+	if (!size)
+		return -EINVAL;
+
+	rc = ntb_mw_get_align(nt->ndev, PIDX, num_mw, &xlat_align,
+			      &xlat_align_size, NULL);
+	if (rc)
+		return rc;
+
+	xlat_size = round_up(size, xlat_align_size);
+	buff_size = round_up(size, xlat_align);
+
+	/* No need to re-setup */
+	if (mw->xlat_size == xlat_size)
+		return 0;
+
+	if (mw->buff_size)
+		ntb_free_mw(nt, num_mw);
+
+	/* Alloc memory for receiving data.  Must be aligned */
+	mw->xlat_size = xlat_size;
+	mw->buff_size = buff_size;
+	mw->alloc_size = buff_size;
+
+	rc = ntb_alloc_mw_buffer(mw, &pdev->dev, xlat_align);
+	if (rc) {
+		mw->alloc_size *= 2;
+		rc = ntb_alloc_mw_buffer(mw, &pdev->dev, xlat_align);
+		if (rc) {
+			dev_err(&pdev->dev,
+				"Unable to alloc aligned MW buff\n");
+			mw->xlat_size = 0;
+			mw->buff_size = 0;
+			mw->alloc_size = 0;
+			return rc;
+		}
+	}
+
+	/* Notify HW the memory location of the receive buffer */
+	rc = ntb_mw_set_trans(nt->ndev, PIDX, num_mw, mw->dma_addr,
+			      mw->xlat_size);
+	if (rc) {
+		dev_err(&pdev->dev, "Unable to set mw%d translation", num_mw);
+		ntb_free_mw(nt, num_mw);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static void ntb_qp_link_context_reset(struct ntb_transport_qp *qp)
+{
+	qp->link_is_up = false;
+	qp->active = false;
+
+	qp->tx_index = 0;
+	qp->rx_index = 0;
+	qp->rx_bytes = 0;
+	qp->rx_pkts = 0;
+	qp->rx_ring_empty = 0;
+	qp->rx_err_no_buf = 0;
+	qp->rx_err_oflow = 0;
+	qp->rx_err_ver = 0;
+	qp->rx_memcpy = 0;
+	qp->rx_async = 0;
+	qp->tx_bytes = 0;
+	qp->tx_pkts = 0;
+	qp->tx_ring_full = 0;
+	qp->tx_err_no_buf = 0;
+	qp->tx_memcpy = 0;
+	qp->tx_async = 0;
+}
+
+static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
+{
+	ntb_qp_link_context_reset(qp);
+	if (qp->remote_rx_info)
+		qp->remote_rx_info->entry = qp->rx_max_entry - 1;
+}
+
+static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
+{
+	struct ntb_transport_ctx *nt = qp->transport;
+	struct pci_dev *pdev = nt->ndev->pdev;
+
+	dev_info(&pdev->dev, "qp %d: Link Cleanup\n", qp->qp_num);
+
+	cancel_delayed_work_sync(&qp->link_work);
+	ntb_qp_link_down_reset(qp);
+
+	if (qp->event_handler)
+		qp->event_handler(qp->cb_data, qp->link_is_up);
+}
+
+static void ntb_qp_link_cleanup_work(struct work_struct *work)
+{
+	struct ntb_transport_qp *qp = container_of(work,
+						   struct ntb_transport_qp,
+						   link_cleanup);
+	struct ntb_transport_ctx *nt = qp->transport;
+
+	ntb_qp_link_cleanup(qp);
+
+	if (nt->link_is_up)
+		schedule_delayed_work(&qp->link_work,
+				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
+}
+
+static void ntb_qp_link_down(struct ntb_transport_qp *qp)
+{
+	schedule_work(&qp->link_cleanup);
+}
+
+static void ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
+{
+	struct ntb_transport_qp *qp;
+	u64 qp_bitmap_alloc;
+	unsigned int i, count;
+
+	qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
+
+	/* Pass along the info to any clients */
+	for (i = 0; i < nt->qp_count; i++)
+		if (qp_bitmap_alloc & BIT_ULL(i)) {
+			qp = &nt->qp_vec[i];
+			ntb_qp_link_cleanup(qp);
+			cancel_work_sync(&qp->link_cleanup);
+			cancel_delayed_work_sync(&qp->link_work);
+		}
+
+	if (!nt->link_is_up)
+		cancel_delayed_work_sync(&nt->link_work);
+
+	for (i = 0; i < nt->mw_count; i++)
+		ntb_free_mw(nt, i);
+
+	/* The scratchpad registers keep the values if the remote side
+	 * goes down, blast them now to give them a sane value the next
+	 * time they are accessed
+	 */
+	count = ntb_spad_count(nt->ndev);
+	for (i = 0; i < count; i++)
+		ntb_spad_write(nt->ndev, i, 0);
+}
+
+static void ntb_transport_link_cleanup_work(struct work_struct *work)
+{
+	struct ntb_transport_ctx *nt =
+		container_of(work, struct ntb_transport_ctx, link_cleanup);
+
+	ntb_transport_link_cleanup(nt);
+}
+
+static void ntb_transport_event_callback(void *data)
+{
+	struct ntb_transport_ctx *nt = data;
+
+	if (ntb_link_is_up(nt->ndev, NULL, NULL) == 1)
+		schedule_delayed_work(&nt->link_work, 0);
+	else
+		schedule_work(&nt->link_cleanup);
+}
+
+static void ntb_transport_link_work(struct work_struct *work)
+{
+	struct ntb_transport_ctx *nt =
+		container_of(work, struct ntb_transport_ctx, link_work.work);
+	struct ntb_dev *ndev = nt->ndev;
+	struct pci_dev *pdev = ndev->pdev;
+	resource_size_t size;
+	u32 val;
+	int rc = 0, i, spad;
+
+	/* send the local info, in the opposite order of the way we read it */
+
+	if (nt->use_msi) {
+		rc = ntb_msi_setup_mws(ndev);
+		if (rc) {
+			dev_warn(&pdev->dev,
+				 "Failed to register MSI memory window: %d\n",
+				 rc);
+			nt->use_msi = false;
+		}
+	}
+
+	for (i = 0; i < nt->qp_count; i++)
+		ntb_transport_setup_qp_msi(nt, i);
+
+	for (i = 0; i < nt->mw_count; i++) {
+		size = nt->mw_vec[i].phys_size;
+
+		if (max_mw_size && size > max_mw_size)
+			size = max_mw_size;
+
+		spad = MW0_SZ_HIGH + (i * 2);
+		ntb_peer_spad_write(ndev, PIDX, spad, upper_32_bits(size));
+
+		spad = MW0_SZ_LOW + (i * 2);
+		ntb_peer_spad_write(ndev, PIDX, spad, lower_32_bits(size));
+	}
+
+	ntb_peer_spad_write(ndev, PIDX, NUM_MWS, nt->mw_count);
+
+	ntb_peer_spad_write(ndev, PIDX, NUM_QPS, nt->qp_count);
+
+	ntb_peer_spad_write(ndev, PIDX, VERSION, NTB_TRANSPORT_VERSION);
+
+	/* Query the remote side for its info */
+	val = ntb_spad_read(ndev, VERSION);
+	dev_dbg(&pdev->dev, "Remote version = %d\n", val);
+	if (val != NTB_TRANSPORT_VERSION)
+		goto out;
+
+	val = ntb_spad_read(ndev, NUM_QPS);
+	dev_dbg(&pdev->dev, "Remote max number of qps = %d\n", val);
+	if (val != nt->qp_count)
+		goto out;
+
+	val = ntb_spad_read(ndev, NUM_MWS);
+	dev_dbg(&pdev->dev, "Remote number of mws = %d\n", val);
+	if (val != nt->mw_count)
+		goto out;
+
+	for (i = 0; i < nt->mw_count; i++) {
+		u64 val64;
+
+		val = ntb_spad_read(ndev, MW0_SZ_HIGH + (i * 2));
+		val64 = (u64)val << 32;
+
+		val = ntb_spad_read(ndev, MW0_SZ_LOW + (i * 2));
+		val64 |= val;
+
+		dev_dbg(&pdev->dev, "Remote MW%d size = %#llx\n", i, val64);
+
+		rc = ntb_set_mw(nt, i, val64);
+		if (rc)
+			goto out1;
+	}
+
+	nt->link_is_up = true;
+
+	for (i = 0; i < nt->qp_count; i++) {
+		struct ntb_transport_qp *qp = &nt->qp_vec[i];
+
+		ntb_transport_setup_qp_mw(nt, i);
+		ntb_transport_setup_qp_peer_msi(nt, i);
+
+		if (qp->client_ready)
+			schedule_delayed_work(&qp->link_work, 0);
+	}
+
+	return;
+
+out1:
+	for (i = 0; i < nt->mw_count; i++)
+		ntb_free_mw(nt, i);
+
+	/* if there's an actual failure, we should just bail */
+	if (rc < 0)
+		return;
+
+out:
+	if (ntb_link_is_up(ndev, NULL, NULL) == 1)
+		schedule_delayed_work(&nt->link_work,
+				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
+}
+
+static void ntb_qp_link_work(struct work_struct *work)
+{
+	struct ntb_transport_qp *qp = container_of(work,
+						   struct ntb_transport_qp,
+						   link_work.work);
+	struct pci_dev *pdev = qp->ndev->pdev;
+	struct ntb_transport_ctx *nt = qp->transport;
+	int val;
+
+	WARN_ON(!nt->link_is_up);
+
+	val = ntb_spad_read(nt->ndev, QP_LINKS);
+
+	ntb_peer_spad_write(nt->ndev, PIDX, QP_LINKS, val | BIT(qp->qp_num));
+
+	/* query remote spad for qp ready bits */
+	dev_dbg_ratelimited(&pdev->dev, "Remote QP link status = %x\n", val);
+
+	/* See if the remote side is up */
+	if (val & BIT(qp->qp_num)) {
+		dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
+		qp->link_is_up = true;
+		qp->active = true;
+
+		if (qp->event_handler)
+			qp->event_handler(qp->cb_data, qp->link_is_up);
+
+		if (qp->active)
+			tasklet_schedule(&qp->rxc_db_work);
+	} else if (nt->link_is_up)
+		schedule_delayed_work(&qp->link_work,
+				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
+}
+
+static int ntb_transport_init_queue(struct ntb_transport_ctx *nt,
+				    unsigned int qp_num)
+{
+	struct ntb_transport_qp *qp;
+	phys_addr_t mw_base;
+	resource_size_t mw_size;
+	unsigned int num_qps_mw, tx_size;
+	unsigned int mw_num, mw_count, qp_count;
+	u64 qp_offset;
+
+	mw_count = nt->mw_count;
+	qp_count = nt->qp_count;
+
+	mw_num = QP_TO_MW(nt, qp_num);
+
+	qp = &nt->qp_vec[qp_num];
+	qp->qp_num = qp_num;
+	qp->transport = nt;
+	qp->ndev = nt->ndev;
+	qp->client_ready = false;
+	qp->event_handler = NULL;
+	ntb_qp_link_context_reset(qp);
+
+	if (mw_num < qp_count % mw_count)
+		num_qps_mw = qp_count / mw_count + 1;
+	else
+		num_qps_mw = qp_count / mw_count;
+
+	mw_base = nt->mw_vec[mw_num].phys_addr;
+	mw_size = nt->mw_vec[mw_num].phys_size;
+
+	if (max_mw_size && mw_size > max_mw_size)
+		mw_size = max_mw_size;
+
+	tx_size = (unsigned int)mw_size / num_qps_mw;
+	qp_offset = tx_size * (qp_num / mw_count);
+
+	qp->tx_mw_size = tx_size;
+	qp->tx_mw = nt->mw_vec[mw_num].vbase + qp_offset;
+	if (!qp->tx_mw)
+		return -EINVAL;
+
+	qp->tx_mw_phys = mw_base + qp_offset;
+	if (!qp->tx_mw_phys)
+		return -EINVAL;
+
+	tx_size -= sizeof(struct ntb_rx_info);
+	qp->rx_info = qp->tx_mw + tx_size;
+
+	/* Due to housekeeping, there must be atleast 2 buffs */
+	qp->tx_max_frame = min(transport_mtu, tx_size / 2);
+	qp->tx_max_entry = tx_size / qp->tx_max_frame;
+
+	if (nt->debugfs_node_dir) {
+		char debugfs_name[4];
+
+		snprintf(debugfs_name, 4, "qp%d", qp_num);
+		qp->debugfs_dir = debugfs_create_dir(debugfs_name,
+						     nt->debugfs_node_dir);
+
+		qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
+							qp->debugfs_dir, qp,
+							&ntb_qp_debugfs_stats);
+	} else {
+		qp->debugfs_dir = NULL;
+		qp->debugfs_stats = NULL;
+	}
+
+	INIT_DELAYED_WORK(&qp->link_work, ntb_qp_link_work);
+	INIT_WORK(&qp->link_cleanup, ntb_qp_link_cleanup_work);
+
+	spin_lock_init(&qp->ntb_rx_q_lock);
+	spin_lock_init(&qp->ntb_tx_free_q_lock);
+
+	INIT_LIST_HEAD(&qp->rx_post_q);
+	INIT_LIST_HEAD(&qp->rx_pend_q);
+	INIT_LIST_HEAD(&qp->rx_free_q);
+	INIT_LIST_HEAD(&qp->tx_free_q);
+
+	tasklet_init(&qp->rxc_db_work, ntb_transport_rxc_db,
+		     (unsigned long)qp);
+
+	return 0;
+}
+
+static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
+{
+	struct ntb_transport_ctx *nt;
+	struct ntb_transport_mw *mw;
+	unsigned int mw_count, qp_count, spad_count, max_mw_count_for_spads;
+	u64 qp_bitmap;
+	int node;
+	int rc, i;
+
+	mw_count = ntb_peer_mw_count(ndev);
+
+	if (!ndev->ops->mw_set_trans) {
+		dev_err(&ndev->dev, "Inbound MW based NTB API is required\n");
+		return -EINVAL;
+	}
+
+	if (ntb_db_is_unsafe(ndev))
+		dev_dbg(&ndev->dev,
+			"doorbell is unsafe, proceed anyway...\n");
+	if (ntb_spad_is_unsafe(ndev))
+		dev_dbg(&ndev->dev,
+			"scratchpad is unsafe, proceed anyway...\n");
+
+	if (ntb_peer_port_count(ndev) != NTB_DEF_PEER_CNT)
+		dev_warn(&ndev->dev, "Multi-port NTB devices unsupported\n");
+
+	node = dev_to_node(&ndev->dev);
+
+	nt = kzalloc_node(sizeof(*nt), GFP_KERNEL, node);
+	if (!nt)
+		return -ENOMEM;
+
+	nt->ndev = ndev;
+
+	/*
+	 * If we are using MSI, and have at least one extra memory window,
+	 * we will reserve the last MW for the MSI window.
+	 */
+	if (use_msi && mw_count > 1) {
+		rc = ntb_msi_init(ndev, ntb_transport_msi_desc_changed);
+		if (!rc) {
+			mw_count -= 1;
+			nt->use_msi = true;
+		}
+	}
+
+	spad_count = ntb_spad_count(ndev);
+
+	/* Limit the MW's based on the availability of scratchpads */
+
+	if (spad_count < NTB_TRANSPORT_MIN_SPADS) {
+		nt->mw_count = 0;
+		rc = -EINVAL;
+		goto err;
+	}
+
+	max_mw_count_for_spads = (spad_count - MW0_SZ_HIGH) / 2;
+	nt->mw_count = min(mw_count, max_mw_count_for_spads);
+
+	nt->msi_spad_offset = nt->mw_count * 2 + MW0_SZ_HIGH;
+
+	nt->mw_vec = kcalloc_node(mw_count, sizeof(*nt->mw_vec),
+				  GFP_KERNEL, node);
+	if (!nt->mw_vec) {
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	for (i = 0; i < mw_count; i++) {
+		mw = &nt->mw_vec[i];
+
+		rc = ntb_peer_mw_get_addr(ndev, i, &mw->phys_addr,
+					  &mw->phys_size);
+		if (rc)
+			goto err1;
+
+		mw->vbase = ioremap_wc(mw->phys_addr, mw->phys_size);
+		if (!mw->vbase) {
+			rc = -ENOMEM;
+			goto err1;
+		}
+
+		mw->buff_size = 0;
+		mw->xlat_size = 0;
+		mw->virt_addr = NULL;
+		mw->dma_addr = 0;
+	}
+
+	qp_bitmap = ntb_db_valid_mask(ndev);
+
+	qp_count = ilog2(qp_bitmap);
+	if (nt->use_msi) {
+		qp_count -= 1;
+		nt->msi_db_mask = 1 << qp_count;
+		ntb_db_clear_mask(ndev, nt->msi_db_mask);
+	}
+
+	if (max_num_clients && max_num_clients < qp_count)
+		qp_count = max_num_clients;
+	else if (nt->mw_count < qp_count)
+		qp_count = nt->mw_count;
+
+	qp_bitmap &= BIT_ULL(qp_count) - 1;
+
+	nt->qp_count = qp_count;
+	nt->qp_bitmap = qp_bitmap;
+	nt->qp_bitmap_free = qp_bitmap;
+
+	nt->qp_vec = kcalloc_node(qp_count, sizeof(*nt->qp_vec),
+				  GFP_KERNEL, node);
+	if (!nt->qp_vec) {
+		rc = -ENOMEM;
+		goto err1;
+	}
+
+	if (nt_debugfs_dir) {
+		nt->debugfs_node_dir =
+			debugfs_create_dir(pci_name(ndev->pdev),
+					   nt_debugfs_dir);
+	}
+
+	for (i = 0; i < qp_count; i++) {
+		rc = ntb_transport_init_queue(nt, i);
+		if (rc)
+			goto err2;
+	}
+
+	INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work);
+	INIT_WORK(&nt->link_cleanup, ntb_transport_link_cleanup_work);
+
+	rc = ntb_set_ctx(ndev, nt, &ntb_transport_ops);
+	if (rc)
+		goto err2;
+
+	INIT_LIST_HEAD(&nt->client_devs);
+	rc = ntb_bus_init(nt);
+	if (rc)
+		goto err3;
+
+	nt->link_is_up = false;
+	ntb_link_enable(ndev, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
+	ntb_link_event(ndev);
+
+	return 0;
+
+err3:
+	ntb_clear_ctx(ndev);
+err2:
+	kfree(nt->qp_vec);
+err1:
+	while (i--) {
+		mw = &nt->mw_vec[i];
+		iounmap(mw->vbase);
+	}
+	kfree(nt->mw_vec);
+err:
+	kfree(nt);
+	return rc;
+}
+
+static void ntb_transport_free(struct ntb_client *self, struct ntb_dev *ndev)
+{
+	struct ntb_transport_ctx *nt = ndev->ctx;
+	struct ntb_transport_qp *qp;
+	u64 qp_bitmap_alloc;
+	int i;
+
+	ntb_transport_link_cleanup(nt);
+	cancel_work_sync(&nt->link_cleanup);
+	cancel_delayed_work_sync(&nt->link_work);
+
+	qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
+
+	/* verify that all the qp's are freed */
+	for (i = 0; i < nt->qp_count; i++) {
+		qp = &nt->qp_vec[i];
+		if (qp_bitmap_alloc & BIT_ULL(i))
+			ntb_transport_free_queue(qp);
+		debugfs_remove_recursive(qp->debugfs_dir);
+	}
+
+	ntb_link_disable(ndev);
+	ntb_clear_ctx(ndev);
+
+	ntb_bus_remove(nt);
+
+	for (i = nt->mw_count; i--; ) {
+		ntb_free_mw(nt, i);
+		iounmap(nt->mw_vec[i].vbase);
+	}
+
+	kfree(nt->qp_vec);
+	kfree(nt->mw_vec);
+	kfree(nt);
+}
+
+static void ntb_complete_rxc(struct ntb_transport_qp *qp)
+{
+	struct ntb_queue_entry *entry;
+	void *cb_data;
+	unsigned int len;
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
+
+	while (!list_empty(&qp->rx_post_q)) {
+		entry = list_first_entry(&qp->rx_post_q,
+					 struct ntb_queue_entry, entry);
+		if (!(entry->flags & DESC_DONE_FLAG))
+			break;
+
+		entry->rx_hdr->flags = 0;
+		iowrite32(entry->rx_index, &qp->rx_info->entry);
+
+		cb_data = entry->cb_data;
+		len = entry->len;
+
+		list_move_tail(&entry->entry, &qp->rx_free_q);
+
+		spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
+
+		if (qp->rx_handler && qp->client_ready)
+			qp->rx_handler(qp, qp->cb_data, cb_data, len);
+
+		spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
+	}
+
+	spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
+}
+
+static void ntb_rx_copy_callback(void *data,
+				 const struct dmaengine_result *res)
+{
+	struct ntb_queue_entry *entry = data;
+
+	/* we need to check DMA results if we are using DMA */
+	if (res) {
+		enum dmaengine_tx_result dma_err = res->result;
+
+		switch (dma_err) {
+		case DMA_TRANS_READ_FAILED:
+		case DMA_TRANS_WRITE_FAILED:
+			entry->errors++;
+			fallthrough;
+		case DMA_TRANS_ABORTED:
+		{
+			struct ntb_transport_qp *qp = entry->qp;
+			void *offset = qp->rx_buff + qp->rx_max_frame *
+					qp->rx_index;
+
+			ntb_memcpy_rx(entry, offset);
+			qp->rx_memcpy++;
+			return;
+		}
+
+		case DMA_TRANS_NOERROR:
+		default:
+			break;
+		}
+	}
+
+	entry->flags |= DESC_DONE_FLAG;
+
+	ntb_complete_rxc(entry->qp);
+}
+
+static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset)
+{
+	void *buf = entry->buf;
+	size_t len = entry->len;
+
+	memcpy(buf, offset, len);
+
+	/* Ensure that the data is fully copied out before clearing the flag */
+	wmb();
+
+	ntb_rx_copy_callback(entry, NULL);
+}
+
+static int ntb_async_rx_submit(struct ntb_queue_entry *entry, void *offset)
+{
+	struct dma_async_tx_descriptor *txd;
+	struct ntb_transport_qp *qp = entry->qp;
+	struct dma_chan *chan = qp->rx_dma_chan;
+	struct dma_device *device;
+	size_t pay_off, buff_off, len;
+	struct dmaengine_unmap_data *unmap;
+	dma_cookie_t cookie;
+	void *buf = entry->buf;
+
+	len = entry->len;
+	device = chan->device;
+	pay_off = (size_t)offset & ~PAGE_MASK;
+	buff_off = (size_t)buf & ~PAGE_MASK;
+
+	if (!is_dma_copy_aligned(device, pay_off, buff_off, len))
+		goto err;
+
+	unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOWAIT);
+	if (!unmap)
+		goto err;
+
+	unmap->len = len;
+	unmap->addr[0] = dma_map_page(device->dev, virt_to_page(offset),
+				      pay_off, len, DMA_TO_DEVICE);
+	if (dma_mapping_error(device->dev, unmap->addr[0]))
+		goto err_get_unmap;
+
+	unmap->to_cnt = 1;
+
+	unmap->addr[1] = dma_map_page(device->dev, virt_to_page(buf),
+				      buff_off, len, DMA_FROM_DEVICE);
+	if (dma_mapping_error(device->dev, unmap->addr[1]))
+		goto err_get_unmap;
+
+	unmap->from_cnt = 1;
+
+	txd = device->device_prep_dma_memcpy(chan, unmap->addr[1],
+					     unmap->addr[0], len,
+					     DMA_PREP_INTERRUPT);
+	if (!txd)
+		goto err_get_unmap;
+
+	txd->callback_result = ntb_rx_copy_callback;
+	txd->callback_param = entry;
+	dma_set_unmap(txd, unmap);
+
+	cookie = dmaengine_submit(txd);
+	if (dma_submit_error(cookie))
+		goto err_set_unmap;
+
+	dmaengine_unmap_put(unmap);
+
+	qp->last_cookie = cookie;
+
+	qp->rx_async++;
+
+	return 0;
+
+err_set_unmap:
+	dmaengine_unmap_put(unmap);
+err_get_unmap:
+	dmaengine_unmap_put(unmap);
+err:
+	return -ENXIO;
+}
+
+static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset)
+{
+	struct ntb_transport_qp *qp = entry->qp;
+	struct dma_chan *chan = qp->rx_dma_chan;
+	int res;
+
+	if (!chan)
+		goto err;
+
+	if (entry->len < copy_bytes)
+		goto err;
+
+	res = ntb_async_rx_submit(entry, offset);
+	if (res < 0)
+		goto err;
+
+	if (!entry->retries)
+		qp->rx_async++;
+
+	return;
+
+err:
+	ntb_memcpy_rx(entry, offset);
+	qp->rx_memcpy++;
+}
+
+static int ntb_process_rxc(struct ntb_transport_qp *qp)
+{
+	struct ntb_payload_header *hdr;
+	struct ntb_queue_entry *entry;
+	void *offset;
+
+	offset = qp->rx_buff + qp->rx_max_frame * qp->rx_index;
+	hdr = offset + qp->rx_max_frame - sizeof(struct ntb_payload_header);
+
+	dev_dbg(&qp->ndev->pdev->dev, "qp %d: RX ver %u len %d flags %x\n",
+		qp->qp_num, hdr->ver, hdr->len, hdr->flags);
+
+	if (!(hdr->flags & DESC_DONE_FLAG)) {
+		dev_dbg(&qp->ndev->pdev->dev, "done flag not set\n");
+		qp->rx_ring_empty++;
+		return -EAGAIN;
+	}
+
+	if (hdr->flags & LINK_DOWN_FLAG) {
+		dev_dbg(&qp->ndev->pdev->dev, "link down flag set\n");
+		ntb_qp_link_down(qp);
+		hdr->flags = 0;
+		return -EAGAIN;
+	}
+
+	if (hdr->ver != (u32)qp->rx_pkts) {
+		dev_dbg(&qp->ndev->pdev->dev,
+			"version mismatch, expected %llu - got %u\n",
+			qp->rx_pkts, hdr->ver);
+		qp->rx_err_ver++;
+		return -EIO;
+	}
+
+	entry = ntb_list_mv(&qp->ntb_rx_q_lock, &qp->rx_pend_q, &qp->rx_post_q);
+	if (!entry) {
+		dev_dbg(&qp->ndev->pdev->dev, "no receive buffer\n");
+		qp->rx_err_no_buf++;
+		return -EAGAIN;
+	}
+
+	entry->rx_hdr = hdr;
+	entry->rx_index = qp->rx_index;
+
+	if (hdr->len > entry->len) {
+		dev_dbg(&qp->ndev->pdev->dev,
+			"receive buffer overflow! Wanted %d got %d\n",
+			hdr->len, entry->len);
+		qp->rx_err_oflow++;
+
+		entry->len = -EIO;
+		entry->flags |= DESC_DONE_FLAG;
+
+		ntb_complete_rxc(qp);
+	} else {
+		dev_dbg(&qp->ndev->pdev->dev,
+			"RX OK index %u ver %u size %d into buf size %d\n",
+			qp->rx_index, hdr->ver, hdr->len, entry->len);
+
+		qp->rx_bytes += hdr->len;
+		qp->rx_pkts++;
+
+		entry->len = hdr->len;
+
+		ntb_async_rx(entry, offset);
+	}
+
+	qp->rx_index++;
+	qp->rx_index %= qp->rx_max_entry;
+
+	return 0;
+}
+
+static void ntb_transport_rxc_db(unsigned long data)
+{
+	struct ntb_transport_qp *qp = (void *)data;
+	int rc, i;
+
+	dev_dbg(&qp->ndev->pdev->dev, "%s: doorbell %d received\n",
+		__func__, qp->qp_num);
+
+	/* Limit the number of packets processed in a single interrupt to
+	 * provide fairness to others
+	 */
+	for (i = 0; i < qp->rx_max_entry; i++) {
+		rc = ntb_process_rxc(qp);
+		if (rc)
+			break;
+	}
+
+	if (i && qp->rx_dma_chan)
+		dma_async_issue_pending(qp->rx_dma_chan);
+
+	if (i == qp->rx_max_entry) {
+		/* there is more work to do */
+		if (qp->active)
+			tasklet_schedule(&qp->rxc_db_work);
+	} else if (ntb_db_read(qp->ndev) & BIT_ULL(qp->qp_num)) {
+		/* the doorbell bit is set: clear it */
+		ntb_db_clear(qp->ndev, BIT_ULL(qp->qp_num));
+		/* ntb_db_read ensures ntb_db_clear write is committed */
+		ntb_db_read(qp->ndev);
+
+		/* an interrupt may have arrived between finishing
+		 * ntb_process_rxc and clearing the doorbell bit:
+		 * there might be some more work to do.
+		 */
+		if (qp->active)
+			tasklet_schedule(&qp->rxc_db_work);
+	}
+}
+
+static void ntb_tx_copy_callback(void *data,
+				 const struct dmaengine_result *res)
+{
+	struct ntb_queue_entry *entry = data;
+	struct ntb_transport_qp *qp = entry->qp;
+	struct ntb_payload_header __iomem *hdr = entry->tx_hdr;
+
+	/* we need to check DMA results if we are using DMA */
+	if (res) {
+		enum dmaengine_tx_result dma_err = res->result;
+
+		switch (dma_err) {
+		case DMA_TRANS_READ_FAILED:
+		case DMA_TRANS_WRITE_FAILED:
+			entry->errors++;
+			fallthrough;
+		case DMA_TRANS_ABORTED:
+		{
+			void __iomem *offset =
+				qp->tx_mw + qp->tx_max_frame *
+				entry->tx_index;
+
+			/* resubmit via CPU */
+			ntb_memcpy_tx(entry, offset);
+			qp->tx_memcpy++;
+			return;
+		}
+
+		case DMA_TRANS_NOERROR:
+		default:
+			break;
+		}
+	}
+
+	iowrite32(entry->flags | DESC_DONE_FLAG, &hdr->flags);
+
+	if (qp->use_msi)
+		ntb_msi_peer_trigger(qp->ndev, PIDX, &qp->peer_msi_desc);
+	else
+		ntb_peer_db_set(qp->ndev, BIT_ULL(qp->qp_num));
+
+	/* The entry length can only be zero if the packet is intended to be a
+	 * "link down" or similar.  Since no payload is being sent in these
+	 * cases, there is nothing to add to the completion queue.
+	 */
+	if (entry->len > 0) {
+		qp->tx_bytes += entry->len;
+
+		if (qp->tx_handler)
+			qp->tx_handler(qp, qp->cb_data, entry->cb_data,
+				       entry->len);
+	}
+
+	ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q);
+}
+
+static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset)
+{
+#ifdef ARCH_HAS_NOCACHE_UACCESS
+	/*
+	 * Using non-temporal mov to improve performance on non-cached
+	 * writes, even though we aren't actually copying from user space.
+	 */
+	__copy_from_user_inatomic_nocache(offset, entry->buf, entry->len);
+#else
+	memcpy_toio(offset, entry->buf, entry->len);
+#endif
+
+	/* Ensure that the data is fully copied out before setting the flags */
+	wmb();
+
+	ntb_tx_copy_callback(entry, NULL);
+}
+
+static int ntb_async_tx_submit(struct ntb_transport_qp *qp,
+			       struct ntb_queue_entry *entry)
+{
+	struct dma_async_tx_descriptor *txd;
+	struct dma_chan *chan = qp->tx_dma_chan;
+	struct dma_device *device;
+	size_t len = entry->len;
+	void *buf = entry->buf;
+	size_t dest_off, buff_off;
+	struct dmaengine_unmap_data *unmap;
+	dma_addr_t dest;
+	dma_cookie_t cookie;
+
+	device = chan->device;
+	dest = qp->tx_mw_dma_addr + qp->tx_max_frame * entry->tx_index;
+	buff_off = (size_t)buf & ~PAGE_MASK;
+	dest_off = (size_t)dest & ~PAGE_MASK;
+
+	if (!is_dma_copy_aligned(device, buff_off, dest_off, len))
+		goto err;
+
+	unmap = dmaengine_get_unmap_data(device->dev, 1, GFP_NOWAIT);
+	if (!unmap)
+		goto err;
+
+	unmap->len = len;
+	unmap->addr[0] = dma_map_page(device->dev, virt_to_page(buf),
+				      buff_off, len, DMA_TO_DEVICE);
+	if (dma_mapping_error(device->dev, unmap->addr[0]))
+		goto err_get_unmap;
+
+	unmap->to_cnt = 1;
+
+	txd = device->device_prep_dma_memcpy(chan, dest, unmap->addr[0], len,
+					     DMA_PREP_INTERRUPT);
+	if (!txd)
+		goto err_get_unmap;
+
+	txd->callback_result = ntb_tx_copy_callback;
+	txd->callback_param = entry;
+	dma_set_unmap(txd, unmap);
+
+	cookie = dmaengine_submit(txd);
+	if (dma_submit_error(cookie))
+		goto err_set_unmap;
+
+	dmaengine_unmap_put(unmap);
+
+	dma_async_issue_pending(chan);
+
+	return 0;
+err_set_unmap:
+	dmaengine_unmap_put(unmap);
+err_get_unmap:
+	dmaengine_unmap_put(unmap);
+err:
+	return -ENXIO;
+}
+
+static void ntb_async_tx(struct ntb_transport_qp *qp,
+			 struct ntb_queue_entry *entry)
+{
+	struct ntb_payload_header __iomem *hdr;
+	struct dma_chan *chan = qp->tx_dma_chan;
+	void __iomem *offset;
+	int res;
+
+	entry->tx_index = qp->tx_index;
+	offset = qp->tx_mw + qp->tx_max_frame * entry->tx_index;
+	hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header);
+	entry->tx_hdr = hdr;
+
+	iowrite32(entry->len, &hdr->len);
+	iowrite32((u32)qp->tx_pkts, &hdr->ver);
+
+	if (!chan)
+		goto err;
+
+	if (entry->len < copy_bytes)
+		goto err;
+
+	res = ntb_async_tx_submit(qp, entry);
+	if (res < 0)
+		goto err;
+
+	if (!entry->retries)
+		qp->tx_async++;
+
+	return;
+
+err:
+	ntb_memcpy_tx(entry, offset);
+	qp->tx_memcpy++;
+}
+
+static int ntb_process_tx(struct ntb_transport_qp *qp,
+			  struct ntb_queue_entry *entry)
+{
+	if (qp->tx_index == qp->remote_rx_info->entry) {
+		qp->tx_ring_full++;
+		return -EAGAIN;
+	}
+
+	if (entry->len > qp->tx_max_frame - sizeof(struct ntb_payload_header)) {
+		if (qp->tx_handler)
+			qp->tx_handler(qp, qp->cb_data, NULL, -EIO);
+
+		ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
+			     &qp->tx_free_q);
+		return 0;
+	}
+
+	ntb_async_tx(qp, entry);
+
+	qp->tx_index++;
+	qp->tx_index %= qp->tx_max_entry;
+
+	qp->tx_pkts++;
+
+	return 0;
+}
+
+static void ntb_send_link_down(struct ntb_transport_qp *qp)
+{
+	struct pci_dev *pdev = qp->ndev->pdev;
+	struct ntb_queue_entry *entry;
+	int i, rc;
+
+	if (!qp->link_is_up)
+		return;
+
+	dev_info(&pdev->dev, "qp %d: Send Link Down\n", qp->qp_num);
+
+	for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
+		entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
+		if (entry)
+			break;
+		msleep(100);
+	}
+
+	if (!entry)
+		return;
+
+	entry->cb_data = NULL;
+	entry->buf = NULL;
+	entry->len = 0;
+	entry->flags = LINK_DOWN_FLAG;
+
+	rc = ntb_process_tx(qp, entry);
+	if (rc)
+		dev_err(&pdev->dev, "ntb: QP%d unable to send linkdown msg\n",
+			qp->qp_num);
+
+	ntb_qp_link_down_reset(qp);
+}
+
+static bool ntb_dma_filter_fn(struct dma_chan *chan, void *node)
+{
+	return dev_to_node(&chan->dev->device) == (int)(unsigned long)node;
+}
+
+/**
+ * ntb_transport_create_queue - Create a new NTB transport layer queue
+ * @rx_handler: receive callback function
+ * @tx_handler: transmit callback function
+ * @event_handler: event callback function
+ *
+ * Create a new NTB transport layer queue and provide the queue with a callback
+ * routine for both transmit and receive.  The receive callback routine will be
+ * used to pass up data when the transport has received it on the queue.   The
+ * transmit callback routine will be called when the transport has completed the
+ * transmission of the data on the queue and the data is ready to be freed.
+ *
+ * RETURNS: pointer to newly created ntb_queue, NULL on error.
+ */
+struct ntb_transport_qp *
+ntb_transport_create_queue(void *data, struct device *client_dev,
+			   const struct ntb_queue_handlers *handlers)
+{
+	struct ntb_dev *ndev;
+	struct pci_dev *pdev;
+	struct ntb_transport_ctx *nt;
+	struct ntb_queue_entry *entry;
+	struct ntb_transport_qp *qp;
+	u64 qp_bit;
+	unsigned int free_queue;
+	dma_cap_mask_t dma_mask;
+	int node;
+	int i;
+
+	ndev = dev_ntb(client_dev->parent);
+	pdev = ndev->pdev;
+	nt = ndev->ctx;
+
+	node = dev_to_node(&ndev->dev);
+
+	free_queue = ffs(nt->qp_bitmap_free);
+	if (!free_queue)
+		goto err;
+
+	/* decrement free_queue to make it zero based */
+	free_queue--;
+
+	qp = &nt->qp_vec[free_queue];
+	qp_bit = BIT_ULL(qp->qp_num);
+
+	nt->qp_bitmap_free &= ~qp_bit;
+
+	qp->cb_data = data;
+	qp->rx_handler = handlers->rx_handler;
+	qp->tx_handler = handlers->tx_handler;
+	qp->event_handler = handlers->event_handler;
+
+	dma_cap_zero(dma_mask);
+	dma_cap_set(DMA_MEMCPY, dma_mask);
+
+	if (use_dma) {
+		qp->tx_dma_chan =
+			dma_request_channel(dma_mask, ntb_dma_filter_fn,
+					    (void *)(unsigned long)node);
+		if (!qp->tx_dma_chan)
+			dev_info(&pdev->dev, "Unable to allocate TX DMA channel\n");
+
+		qp->rx_dma_chan =
+			dma_request_channel(dma_mask, ntb_dma_filter_fn,
+					    (void *)(unsigned long)node);
+		if (!qp->rx_dma_chan)
+			dev_info(&pdev->dev, "Unable to allocate RX DMA channel\n");
+	} else {
+		qp->tx_dma_chan = NULL;
+		qp->rx_dma_chan = NULL;
+	}
+
+	qp->tx_mw_dma_addr = 0;
+	if (qp->tx_dma_chan) {
+		qp->tx_mw_dma_addr =
+			dma_map_resource(qp->tx_dma_chan->device->dev,
+					 qp->tx_mw_phys, qp->tx_mw_size,
+					 DMA_FROM_DEVICE, 0);
+		if (dma_mapping_error(qp->tx_dma_chan->device->dev,
+				      qp->tx_mw_dma_addr)) {
+			qp->tx_mw_dma_addr = 0;
+			goto err1;
+		}
+	}
+
+	dev_dbg(&pdev->dev, "Using %s memcpy for TX\n",
+		qp->tx_dma_chan ? "DMA" : "CPU");
+
+	dev_dbg(&pdev->dev, "Using %s memcpy for RX\n",
+		qp->rx_dma_chan ? "DMA" : "CPU");
+
+	for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
+		entry = kzalloc_node(sizeof(*entry), GFP_KERNEL, node);
+		if (!entry)
+			goto err1;
+
+		entry->qp = qp;
+		ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry,
+			     &qp->rx_free_q);
+	}
+	qp->rx_alloc_entry = NTB_QP_DEF_NUM_ENTRIES;
+
+	for (i = 0; i < qp->tx_max_entry; i++) {
+		entry = kzalloc_node(sizeof(*entry), GFP_KERNEL, node);
+		if (!entry)
+			goto err2;
+
+		entry->qp = qp;
+		ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
+			     &qp->tx_free_q);
+	}
+
+	ntb_db_clear(qp->ndev, qp_bit);
+	ntb_db_clear_mask(qp->ndev, qp_bit);
+
+	dev_info(&pdev->dev, "NTB Transport QP %d created\n", qp->qp_num);
+
+	return qp;
+
+err2:
+	while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
+		kfree(entry);
+err1:
+	qp->rx_alloc_entry = 0;
+	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
+		kfree(entry);
+	if (qp->tx_mw_dma_addr)
+		dma_unmap_resource(qp->tx_dma_chan->device->dev,
+				   qp->tx_mw_dma_addr, qp->tx_mw_size,
+				   DMA_FROM_DEVICE, 0);
+	if (qp->tx_dma_chan)
+		dma_release_channel(qp->tx_dma_chan);
+	if (qp->rx_dma_chan)
+		dma_release_channel(qp->rx_dma_chan);
+	nt->qp_bitmap_free |= qp_bit;
+err:
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
+
+/**
+ * ntb_transport_free_queue - Frees NTB transport queue
+ * @qp: NTB queue to be freed
+ *
+ * Frees NTB transport queue
+ */
+void ntb_transport_free_queue(struct ntb_transport_qp *qp)
+{
+	struct pci_dev *pdev;
+	struct ntb_queue_entry *entry;
+	u64 qp_bit;
+
+	if (!qp)
+		return;
+
+	pdev = qp->ndev->pdev;
+
+	qp->active = false;
+
+	if (qp->tx_dma_chan) {
+		struct dma_chan *chan = qp->tx_dma_chan;
+		/* Putting the dma_chan to NULL will force any new traffic to be
+		 * processed by the CPU instead of the DAM engine
+		 */
+		qp->tx_dma_chan = NULL;
+
+		/* Try to be nice and wait for any queued DMA engine
+		 * transactions to process before smashing it with a rock
+		 */
+		dma_sync_wait(chan, qp->last_cookie);
+		dmaengine_terminate_all(chan);
+
+		dma_unmap_resource(chan->device->dev,
+				   qp->tx_mw_dma_addr, qp->tx_mw_size,
+				   DMA_FROM_DEVICE, 0);
+
+		dma_release_channel(chan);
+	}
+
+	if (qp->rx_dma_chan) {
+		struct dma_chan *chan = qp->rx_dma_chan;
+		/* Putting the dma_chan to NULL will force any new traffic to be
+		 * processed by the CPU instead of the DAM engine
+		 */
+		qp->rx_dma_chan = NULL;
+
+		/* Try to be nice and wait for any queued DMA engine
+		 * transactions to process before smashing it with a rock
+		 */
+		dma_sync_wait(chan, qp->last_cookie);
+		dmaengine_terminate_all(chan);
+		dma_release_channel(chan);
+	}
+
+	qp_bit = BIT_ULL(qp->qp_num);
+
+	ntb_db_set_mask(qp->ndev, qp_bit);
+	tasklet_kill(&qp->rxc_db_work);
+
+	cancel_delayed_work_sync(&qp->link_work);
+
+	qp->cb_data = NULL;
+	qp->rx_handler = NULL;
+	qp->tx_handler = NULL;
+	qp->event_handler = NULL;
+
+	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q)))
+		kfree(entry);
+
+	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q))) {
+		dev_warn(&pdev->dev, "Freeing item from non-empty rx_pend_q\n");
+		kfree(entry);
+	}
+
+	while ((entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_post_q))) {
+		dev_warn(&pdev->dev, "Freeing item from non-empty rx_post_q\n");
+		kfree(entry);
+	}
+
+	while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
+		kfree(entry);
+
+	qp->transport->qp_bitmap_free |= qp_bit;
+
+	dev_info(&pdev->dev, "NTB Transport QP %d freed\n", qp->qp_num);
+}
+EXPORT_SYMBOL_GPL(ntb_transport_free_queue);
+
+/**
+ * ntb_transport_rx_remove - Dequeues enqueued rx packet
+ * @qp: NTB queue to be freed
+ * @len: pointer to variable to write enqueued buffers length
+ *
+ * Dequeues unused buffers from receive queue.  Should only be used during
+ * shutdown of qp.
+ *
+ * RETURNS: NULL error value on error, or void* for success.
+ */
+void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len)
+{
+	struct ntb_queue_entry *entry;
+	void *buf;
+
+	if (!qp || qp->client_ready)
+		return NULL;
+
+	entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_pend_q);
+	if (!entry)
+		return NULL;
+
+	buf = entry->cb_data;
+	*len = entry->len;
+
+	ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_free_q);
+
+	return buf;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_rx_remove);
+
+/**
+ * ntb_transport_rx_enqueue - Enqueue a new NTB queue entry
+ * @qp: NTB transport layer queue the entry is to be enqueued on
+ * @cb: per buffer pointer for callback function to use
+ * @data: pointer to data buffer that incoming packets will be copied into
+ * @len: length of the data buffer
+ *
+ * Enqueue a new receive buffer onto the transport queue into which a NTB
+ * payload can be received into.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
+			     unsigned int len)
+{
+	struct ntb_queue_entry *entry;
+
+	if (!qp)
+		return -EINVAL;
+
+	entry = ntb_list_rm(&qp->ntb_rx_q_lock, &qp->rx_free_q);
+	if (!entry)
+		return -ENOMEM;
+
+	entry->cb_data = cb;
+	entry->buf = data;
+	entry->len = len;
+	entry->flags = 0;
+	entry->retries = 0;
+	entry->errors = 0;
+	entry->rx_index = 0;
+
+	ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_pend_q);
+
+	if (qp->active)
+		tasklet_schedule(&qp->rxc_db_work);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
+
+/**
+ * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
+ * @qp: NTB transport layer queue the entry is to be enqueued on
+ * @cb: per buffer pointer for callback function to use
+ * @data: pointer to data buffer that will be sent
+ * @len: length of the data buffer
+ *
+ * Enqueue a new transmit buffer onto the transport queue from which a NTB
+ * payload will be transmitted.  This assumes that a lock is being held to
+ * serialize access to the qp.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
+			     unsigned int len)
+{
+	struct ntb_queue_entry *entry;
+	int rc;
+
+	if (!qp || !len)
+		return -EINVAL;
+
+	/* If the qp link is down already, just ignore. */
+	if (!qp->link_is_up)
+		return 0;
+
+	entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
+	if (!entry) {
+		qp->tx_err_no_buf++;
+		return -EBUSY;
+	}
+
+	entry->cb_data = cb;
+	entry->buf = data;
+	entry->len = len;
+	entry->flags = 0;
+	entry->errors = 0;
+	entry->retries = 0;
+	entry->tx_index = 0;
+
+	rc = ntb_process_tx(qp, entry);
+	if (rc)
+		ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
+			     &qp->tx_free_q);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_tx_enqueue);
+
+/**
+ * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
+ * @qp: NTB transport layer queue to be enabled
+ *
+ * Notify NTB transport layer of client readiness to use queue
+ */
+void ntb_transport_link_up(struct ntb_transport_qp *qp)
+{
+	if (!qp)
+		return;
+
+	qp->client_ready = true;
+
+	if (qp->transport->link_is_up)
+		schedule_delayed_work(&qp->link_work, 0);
+}
+EXPORT_SYMBOL_GPL(ntb_transport_link_up);
+
+/**
+ * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
+ * @qp: NTB transport layer queue to be disabled
+ *
+ * Notify NTB transport layer of client's desire to no longer receive data on
+ * transport queue specified.  It is the client's responsibility to ensure all
+ * entries on queue are purged or otherwise handled appropriately.
+ */
+void ntb_transport_link_down(struct ntb_transport_qp *qp)
+{
+	int val;
+
+	if (!qp)
+		return;
+
+	qp->client_ready = false;
+
+	val = ntb_spad_read(qp->ndev, QP_LINKS);
+
+	ntb_peer_spad_write(qp->ndev, PIDX, QP_LINKS, val & ~BIT(qp->qp_num));
+
+	if (qp->link_is_up)
+		ntb_send_link_down(qp);
+	else
+		cancel_delayed_work_sync(&qp->link_work);
+}
+EXPORT_SYMBOL_GPL(ntb_transport_link_down);
+
+/**
+ * ntb_transport_link_query - Query transport link state
+ * @qp: NTB transport layer queue to be queried
+ *
+ * Query connectivity to the remote system of the NTB transport queue
+ *
+ * RETURNS: true for link up or false for link down
+ */
+bool ntb_transport_link_query(struct ntb_transport_qp *qp)
+{
+	if (!qp)
+		return false;
+
+	return qp->link_is_up;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_link_query);
+
+/**
+ * ntb_transport_qp_num - Query the qp number
+ * @qp: NTB transport layer queue to be queried
+ *
+ * Query qp number of the NTB transport queue
+ *
+ * RETURNS: a zero based number specifying the qp number
+ */
+unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
+{
+	if (!qp)
+		return 0;
+
+	return qp->qp_num;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_qp_num);
+
+/**
+ * ntb_transport_max_size - Query the max payload size of a qp
+ * @qp: NTB transport layer queue to be queried
+ *
+ * Query the maximum payload size permissible on the given qp
+ *
+ * RETURNS: the max payload size of a qp
+ */
+unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp)
+{
+	unsigned int max_size;
+	unsigned int copy_align;
+	struct dma_chan *rx_chan, *tx_chan;
+
+	if (!qp)
+		return 0;
+
+	rx_chan = qp->rx_dma_chan;
+	tx_chan = qp->tx_dma_chan;
+
+	copy_align = max(rx_chan ? rx_chan->device->copy_align : 0,
+			 tx_chan ? tx_chan->device->copy_align : 0);
+
+	/* If DMA engine usage is possible, try to find the max size for that */
+	max_size = qp->tx_max_frame - sizeof(struct ntb_payload_header);
+	max_size = round_down(max_size, 1 << copy_align);
+
+	return max_size;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_max_size);
+
+unsigned int ntb_transport_tx_free_entry(struct ntb_transport_qp *qp)
+{
+	unsigned int head = qp->tx_index;
+	unsigned int tail = qp->remote_rx_info->entry;
+
+	return tail >= head ? tail - head : qp->tx_max_entry + tail - head;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_tx_free_entry);
+
+static void ntb_transport_doorbell_callback(void *data, int vector)
+{
+	struct ntb_transport_ctx *nt = data;
+	struct ntb_transport_qp *qp;
+	u64 db_bits;
+	unsigned int qp_num;
+
+	if (ntb_db_read(nt->ndev) & nt->msi_db_mask) {
+		ntb_transport_msi_peer_desc_changed(nt);
+		ntb_db_clear(nt->ndev, nt->msi_db_mask);
+	}
+
+	db_bits = (nt->qp_bitmap & ~nt->qp_bitmap_free &
+		   ntb_db_vector_mask(nt->ndev, vector));
+
+	while (db_bits) {
+		qp_num = __ffs(db_bits);
+		qp = &nt->qp_vec[qp_num];
+
+		if (qp->active)
+			tasklet_schedule(&qp->rxc_db_work);
+
+		db_bits &= ~BIT_ULL(qp_num);
+	}
+}
+
+static const struct ntb_ctx_ops ntb_transport_ops = {
+	.link_event = ntb_transport_event_callback,
+	.db_event = ntb_transport_doorbell_callback,
+};
+
+static struct ntb_client ntb_transport_client = {
+	.ops = {
+		.probe = ntb_transport_probe,
+		.remove = ntb_transport_free,
+	},
+};
+
+static int __init ntb_transport_init(void)
+{
+	int rc;
+
+	pr_info("%s, version %s\n", NTB_TRANSPORT_DESC, NTB_TRANSPORT_VER);
+
+	if (debugfs_initialized())
+		nt_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
+
+	rc = bus_register(&ntb_transport_bus);
+	if (rc)
+		goto err_bus;
+
+	rc = ntb_register_client(&ntb_transport_client);
+	if (rc)
+		goto err_client;
+
+	return 0;
+
+err_client:
+	bus_unregister(&ntb_transport_bus);
+err_bus:
+	debugfs_remove_recursive(nt_debugfs_dir);
+	return rc;
+}
+module_init(ntb_transport_init);
+
+static void __exit ntb_transport_exit(void)
+{
+	ntb_unregister_client(&ntb_transport_client);
+	bus_unregister(&ntb_transport_bus);
+	debugfs_remove_recursive(nt_debugfs_dir);
+}
+module_exit(ntb_transport_exit);