Initial import

1 files changed, 1776 insertions, 0 deletions

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
new file mode 100644
index 000000000..e9bf2f47b
--- /dev/null
+++ b/drivers/ntb/ntb_transport.c
@@ -0,0 +1,1776 @@
+/*
+ * 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.
+ *
+ *   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.
+ *
+ *   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.
+ *
+ * Intel PCIe NTB 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 "ntb_hw.h"
+
+#define NTB_TRANSPORT_VERSION	3
+
+static unsigned int transport_mtu = 0x401E;
+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");
+
+struct ntb_queue_entry {
+	/* ntb_queue list reference */
+	struct list_head entry;
+	/* pointers to data to be transfered */
+	void *cb_data;
+	void *buf;
+	unsigned int len;
+	unsigned int flags;
+
+	struct ntb_transport_qp *qp;
+	union {
+		struct ntb_payload_header __iomem *tx_hdr;
+		struct ntb_payload_header *rx_hdr;
+	};
+	unsigned int index;
+};
+
+struct ntb_rx_info {
+	unsigned int entry;
+};
+
+struct ntb_transport_qp {
+	struct ntb_transport *transport;
+	struct ntb_device *ndev;
+	void *cb_data;
+	struct dma_chan *dma_chan;
+
+	bool client_ready;
+	bool qp_link;
+	u8 qp_num;	/* Only 64 QP's are allowed.  0-63 */
+
+	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;
+	dma_addr_t tx_mw_phys;
+	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_pend_q;
+	struct list_head rx_free_q;
+	spinlock_t ntb_rx_pend_q_lock;
+	spinlock_t ntb_rx_free_q_lock;
+	void *rx_buff;
+	unsigned int rx_index;
+	unsigned int rx_max_entry;
+	unsigned int rx_max_frame;
+	dma_cookie_t last_cookie;
+
+	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;
+};
+
+struct ntb_transport_mw {
+	size_t size;
+	void *virt_addr;
+	dma_addr_t dma_addr;
+};
+
+struct ntb_transport_client_dev {
+	struct list_head entry;
+	struct device dev;
+};
+
+struct ntb_transport {
+	struct list_head entry;
+	struct list_head client_devs;
+
+	struct ntb_device *ndev;
+	struct ntb_transport_mw *mw;
+	struct ntb_transport_qp *qps;
+	unsigned int max_qps;
+	unsigned long qp_bitmap;
+	bool transport_link;
+	struct delayed_work link_work;
+	struct work_struct link_cleanup;
+};
+
+enum {
+	DESC_DONE_FLAG = 1 << 0,
+	LINK_DOWN_FLAG = 1 << 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,
+	MW1_SZ_HIGH,
+	MW1_SZ_LOW,
+	MAX_SPAD,
+};
+
+#define QP_TO_MW(ndev, qp)	((qp) % ntb_max_mw(ndev))
+#define NTB_QP_DEF_NUM_ENTRIES	100
+#define NTB_LINK_DOWN_TIMEOUT	10
+
+static int ntb_match_bus(struct device *dev, struct device_driver *drv)
+{
+	return !strncmp(dev_name(dev), drv->name, strlen(drv->name));
+}
+
+static int ntb_client_probe(struct device *dev)
+{
+	const struct ntb_client *drv = container_of(dev->driver,
+						    struct ntb_client, driver);
+	struct pci_dev *pdev = container_of(dev->parent, struct pci_dev, dev);
+	int rc = -EINVAL;
+
+	get_device(dev);
+	if (drv && drv->probe)
+		rc = drv->probe(pdev);
+	if (rc)
+		put_device(dev);
+
+	return rc;
+}
+
+static int ntb_client_remove(struct device *dev)
+{
+	const struct ntb_client *drv = container_of(dev->driver,
+						    struct ntb_client, driver);
+	struct pci_dev *pdev = container_of(dev->parent, struct pci_dev, dev);
+
+	if (drv && drv->remove)
+		drv->remove(pdev);
+
+	put_device(dev);
+
+	return 0;
+}
+
+static struct bus_type ntb_bus_type = {
+	.name = "ntb_bus",
+	.match = ntb_match_bus,
+	.probe = ntb_client_probe,
+	.remove = ntb_client_remove,
+};
+
+static LIST_HEAD(ntb_transport_list);
+
+static int ntb_bus_init(struct ntb_transport *nt)
+{
+	if (list_empty(&ntb_transport_list)) {
+		int rc = bus_register(&ntb_bus_type);
+		if (rc)
+			return rc;
+	}
+
+	list_add(&nt->entry, &ntb_transport_list);
+
+	return 0;
+}
+
+static void ntb_bus_remove(struct ntb_transport *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);
+
+	if (list_empty(&ntb_transport_list))
+		bus_unregister(&ntb_bus_type);
+}
+
+static void ntb_client_release(struct device *dev)
+{
+	struct ntb_transport_client_dev *client_dev;
+	client_dev = container_of(dev, struct ntb_transport_client_dev, dev);
+
+	kfree(client_dev);
+}
+
+/**
+ * ntb_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_unregister_client_dev(char *device_name)
+{
+	struct ntb_transport_client_dev *client, *cd;
+	struct ntb_transport *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_unregister_client_dev);
+
+/**
+ * ntb_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_register_client_dev(char *device_name)
+{
+	struct ntb_transport_client_dev *client_dev;
+	struct ntb_transport *nt;
+	int rc, i = 0;
+
+	if (list_empty(&ntb_transport_list))
+		return -ENODEV;
+
+	list_for_each_entry(nt, &ntb_transport_list, entry) {
+		struct device *dev;
+
+		client_dev = kzalloc(sizeof(struct ntb_transport_client_dev),
+				     GFP_KERNEL);
+		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_bus_type;
+		dev->release = ntb_client_release;
+		dev->parent = &ntb_query_pdev(nt->ndev)->dev;
+
+		rc = device_register(dev);
+		if (rc) {
+			kfree(client_dev);
+			goto err;
+		}
+
+		list_add_tail(&client_dev->entry, &nt->client_devs);
+		i++;
+	}
+
+	return 0;
+
+err:
+	ntb_unregister_client_dev(device_name);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(ntb_register_client_dev);
+
+/**
+ * ntb_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_register_client(struct ntb_client *drv)
+{
+	drv->driver.bus = &ntb_bus_type;
+
+	if (list_empty(&ntb_transport_list))
+		return -ENODEV;
+
+	return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(ntb_register_client);
+
+/**
+ * ntb_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_unregister_client(struct ntb_client *drv)
+{
+	driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(ntb_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;
+
+	out_count = 1000;
+
+	buf = kmalloc(out_count, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	qp = filp->private_data;
+	out_offset = 0;
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "NTB QP stats\n");
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "rx_bytes - \t%llu\n", qp->rx_bytes);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "rx_pkts - \t%llu\n", qp->rx_pkts);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "rx_memcpy - \t%llu\n", qp->rx_memcpy);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "rx_async - \t%llu\n", qp->rx_async);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "rx_ring_empty - %llu\n", qp->rx_ring_empty);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "rx_err_no_buf - %llu\n", qp->rx_err_no_buf);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "rx_err_oflow - \t%llu\n", qp->rx_err_oflow);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "rx_err_ver - \t%llu\n", qp->rx_err_ver);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "rx_buff - \t%p\n", qp->rx_buff);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "rx_index - \t%u\n", qp->rx_index);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "rx_max_entry - \t%u\n", qp->rx_max_entry);
+
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "tx_bytes - \t%llu\n", qp->tx_bytes);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "tx_pkts - \t%llu\n", qp->tx_pkts);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "tx_memcpy - \t%llu\n", qp->tx_memcpy);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "tx_async - \t%llu\n", qp->tx_async);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "tx_ring_full - \t%llu\n", qp->tx_ring_full);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "tx_err_no_buf - %llu\n", qp->tx_err_no_buf);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "tx_mw - \t%p\n", qp->tx_mw);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "tx_index - \t%u\n", qp->tx_index);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "tx_max_entry - \t%u\n", qp->tx_max_entry);
+
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "\nQP Link %s\n", (qp->qp_link == NTB_LINK_UP) ?
+			       "Up" : "Down");
+	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 void ntb_transport_setup_qp_mw(struct ntb_transport *nt,
+				      unsigned int qp_num)
+{
+	struct ntb_transport_qp *qp = &nt->qps[qp_num];
+	unsigned int rx_size, num_qps_mw;
+	u8 mw_num, mw_max;
+	unsigned int i;
+
+	mw_max = ntb_max_mw(nt->ndev);
+	mw_num = QP_TO_MW(nt->ndev, qp_num);
+
+	WARN_ON(nt->mw[mw_num].virt_addr == NULL);
+
+	if (nt->max_qps % mw_max && mw_num + 1 < nt->max_qps / mw_max)
+		num_qps_mw = nt->max_qps / mw_max + 1;
+	else
+		num_qps_mw = nt->max_qps / mw_max;
+
+	rx_size = (unsigned int) nt->mw[mw_num].size / num_qps_mw;
+	qp->rx_buff = nt->mw[mw_num].virt_addr + qp_num / mw_max * rx_size;
+	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;
+
+	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;
+}
+
+static void ntb_free_mw(struct ntb_transport *nt, int num_mw)
+{
+	struct ntb_transport_mw *mw = &nt->mw[num_mw];
+	struct pci_dev *pdev = ntb_query_pdev(nt->ndev);
+
+	if (!mw->virt_addr)
+		return;
+
+	dma_free_coherent(&pdev->dev, mw->size, mw->virt_addr, mw->dma_addr);
+	mw->virt_addr = NULL;
+}
+
+static int ntb_set_mw(struct ntb_transport *nt, int num_mw, unsigned int size)
+{
+	struct ntb_transport_mw *mw = &nt->mw[num_mw];
+	struct pci_dev *pdev = ntb_query_pdev(nt->ndev);
+
+	/* No need to re-setup */
+	if (mw->size == ALIGN(size, 4096))
+		return 0;
+
+	if (mw->size != 0)
+		ntb_free_mw(nt, num_mw);
+
+	/* Alloc memory for receiving data.  Must be 4k aligned */
+	mw->size = ALIGN(size, 4096);
+
+	mw->virt_addr = dma_alloc_coherent(&pdev->dev, mw->size, &mw->dma_addr,
+					   GFP_KERNEL);
+	if (!mw->virt_addr) {
+		mw->size = 0;
+		dev_err(&pdev->dev, "Unable to allocate MW buffer of size %d\n",
+		       (int) mw->size);
+		return -ENOMEM;
+	}
+
+	/*
+	 * 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(mw->dma_addr, mw->size)) {
+		dev_err(&pdev->dev, "DMA memory %pad not aligned to BAR size\n",
+			&mw->dma_addr);
+		ntb_free_mw(nt, num_mw);
+		return -ENOMEM;
+	}
+
+	/* Notify HW the memory location of the receive buffer */
+	ntb_set_mw_addr(nt->ndev, num_mw, mw->dma_addr);
+
+	return 0;
+}
+
+static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
+{
+	struct ntb_transport *nt = qp->transport;
+	struct pci_dev *pdev = ntb_query_pdev(nt->ndev);
+
+	if (qp->qp_link == NTB_LINK_DOWN) {
+		cancel_delayed_work_sync(&qp->link_work);
+		return;
+	}
+
+	if (qp->event_handler)
+		qp->event_handler(qp->cb_data, NTB_LINK_DOWN);
+
+	dev_info(&pdev->dev, "qp %d: Link Down\n", qp->qp_num);
+	qp->qp_link = NTB_LINK_DOWN;
+}
+
+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 *nt = qp->transport;
+
+	ntb_qp_link_cleanup(qp);
+
+	if (nt->transport_link == NTB_LINK_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 *nt)
+{
+	int i;
+
+	/* Pass along the info to any clients */
+	for (i = 0; i < nt->max_qps; i++)
+		if (!test_bit(i, &nt->qp_bitmap))
+			ntb_qp_link_cleanup(&nt->qps[i]);
+
+	if (nt->transport_link == NTB_LINK_DOWN)
+		cancel_delayed_work_sync(&nt->link_work);
+	else
+		nt->transport_link = NTB_LINK_DOWN;
+
+	/* 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
+	 */
+	for (i = 0; i < MAX_SPAD; i++)
+		ntb_write_local_spad(nt->ndev, i, 0);
+}
+
+static void ntb_transport_link_cleanup_work(struct work_struct *work)
+{
+	struct ntb_transport *nt = container_of(work, struct ntb_transport,
+						link_cleanup);
+
+	ntb_transport_link_cleanup(nt);
+}
+
+static void ntb_transport_event_callback(void *data, enum ntb_hw_event event)
+{
+	struct ntb_transport *nt = data;
+
+	switch (event) {
+	case NTB_EVENT_HW_LINK_UP:
+		schedule_delayed_work(&nt->link_work, 0);
+		break;
+	case NTB_EVENT_HW_LINK_DOWN:
+		schedule_work(&nt->link_cleanup);
+		break;
+	default:
+		BUG();
+	}
+}
+
+static void ntb_transport_link_work(struct work_struct *work)
+{
+	struct ntb_transport *nt = container_of(work, struct ntb_transport,
+						link_work.work);
+	struct ntb_device *ndev = nt->ndev;
+	struct pci_dev *pdev = ntb_query_pdev(ndev);
+	u32 val;
+	int rc, i;
+
+	/* send the local info, in the opposite order of the way we read it */
+	for (i = 0; i < ntb_max_mw(ndev); i++) {
+		rc = ntb_write_remote_spad(ndev, MW0_SZ_HIGH + (i * 2),
+					   ntb_get_mw_size(ndev, i) >> 32);
+		if (rc) {
+			dev_err(&pdev->dev, "Error writing %u to remote spad %d\n",
+				(u32)(ntb_get_mw_size(ndev, i) >> 32),
+				MW0_SZ_HIGH + (i * 2));
+			goto out;
+		}
+
+		rc = ntb_write_remote_spad(ndev, MW0_SZ_LOW + (i * 2),
+					   (u32) ntb_get_mw_size(ndev, i));
+		if (rc) {
+			dev_err(&pdev->dev, "Error writing %u to remote spad %d\n",
+				(u32) ntb_get_mw_size(ndev, i),
+				MW0_SZ_LOW + (i * 2));
+			goto out;
+		}
+	}
+
+	rc = ntb_write_remote_spad(ndev, NUM_MWS, ntb_max_mw(ndev));
+	if (rc) {
+		dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
+			ntb_max_mw(ndev), NUM_MWS);
+		goto out;
+	}
+
+	rc = ntb_write_remote_spad(ndev, NUM_QPS, nt->max_qps);
+	if (rc) {
+		dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
+			nt->max_qps, NUM_QPS);
+		goto out;
+	}
+
+	rc = ntb_write_remote_spad(ndev, VERSION, NTB_TRANSPORT_VERSION);
+	if (rc) {
+		dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
+			NTB_TRANSPORT_VERSION, VERSION);
+		goto out;
+	}
+
+	/* Query the remote side for its info */
+	rc = ntb_read_remote_spad(ndev, VERSION, &val);
+	if (rc) {
+		dev_err(&pdev->dev, "Error reading remote spad %d\n", VERSION);
+		goto out;
+	}
+
+	if (val != NTB_TRANSPORT_VERSION)
+		goto out;
+	dev_dbg(&pdev->dev, "Remote version = %d\n", val);
+
+	rc = ntb_read_remote_spad(ndev, NUM_QPS, &val);
+	if (rc) {
+		dev_err(&pdev->dev, "Error reading remote spad %d\n", NUM_QPS);
+		goto out;
+	}
+
+	if (val != nt->max_qps)
+		goto out;
+	dev_dbg(&pdev->dev, "Remote max number of qps = %d\n", val);
+
+	rc = ntb_read_remote_spad(ndev, NUM_MWS, &val);
+	if (rc) {
+		dev_err(&pdev->dev, "Error reading remote spad %d\n", NUM_MWS);
+		goto out;
+	}
+
+	if (val != ntb_max_mw(ndev))
+		goto out;
+	dev_dbg(&pdev->dev, "Remote number of mws = %d\n", val);
+
+	for (i = 0; i < ntb_max_mw(ndev); i++) {
+		u64 val64;
+
+		rc = ntb_read_remote_spad(ndev, MW0_SZ_HIGH + (i * 2), &val);
+		if (rc) {
+			dev_err(&pdev->dev, "Error reading remote spad %d\n",
+				MW0_SZ_HIGH + (i * 2));
+			goto out1;
+		}
+
+		val64 = (u64) val << 32;
+
+		rc = ntb_read_remote_spad(ndev, MW0_SZ_LOW + (i * 2), &val);
+		if (rc) {
+			dev_err(&pdev->dev, "Error reading remote spad %d\n",
+				MW0_SZ_LOW + (i * 2));
+			goto out1;
+		}
+
+		val64 |= val;
+
+		dev_dbg(&pdev->dev, "Remote MW%d size = %llu\n", i, val64);
+
+		rc = ntb_set_mw(nt, i, val64);
+		if (rc)
+			goto out1;
+	}
+
+	nt->transport_link = NTB_LINK_UP;
+
+	for (i = 0; i < nt->max_qps; i++) {
+		struct ntb_transport_qp *qp = &nt->qps[i];
+
+		ntb_transport_setup_qp_mw(nt, i);
+
+		if (qp->client_ready == NTB_LINK_UP)
+			schedule_delayed_work(&qp->link_work, 0);
+	}
+
+	return;
+
+out1:
+	for (i = 0; i < ntb_max_mw(ndev); i++)
+		ntb_free_mw(nt, i);
+out:
+	if (ntb_hw_link_status(ndev))
+		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 = ntb_query_pdev(qp->ndev);
+	struct ntb_transport *nt = qp->transport;
+	int rc, val;
+
+	WARN_ON(nt->transport_link != NTB_LINK_UP);
+
+	rc = ntb_read_local_spad(nt->ndev, QP_LINKS, &val);
+	if (rc) {
+		dev_err(&pdev->dev, "Error reading spad %d\n", QP_LINKS);
+		return;
+	}
+
+	rc = ntb_write_remote_spad(nt->ndev, QP_LINKS, val | 1 << qp->qp_num);
+	if (rc)
+		dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
+			val | 1 << qp->qp_num, QP_LINKS);
+
+	/* query remote spad for qp ready bits */
+	rc = ntb_read_remote_spad(nt->ndev, QP_LINKS, &val);
+	if (rc)
+		dev_err(&pdev->dev, "Error reading remote spad %d\n", QP_LINKS);
+
+	dev_dbg(&pdev->dev, "Remote QP link status = %x\n", val);
+
+	/* See if the remote side is up */
+	if (1 << qp->qp_num & val) {
+		qp->qp_link = NTB_LINK_UP;
+
+		dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
+		if (qp->event_handler)
+			qp->event_handler(qp->cb_data, NTB_LINK_UP);
+	} else if (nt->transport_link == NTB_LINK_UP)
+		schedule_delayed_work(&qp->link_work,
+				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
+}
+
+static int ntb_transport_init_queue(struct ntb_transport *nt,
+				    unsigned int qp_num)
+{
+	struct ntb_transport_qp *qp;
+	unsigned int num_qps_mw, tx_size;
+	u8 mw_num, mw_max;
+	u64 qp_offset;
+
+	mw_max = ntb_max_mw(nt->ndev);
+	mw_num = QP_TO_MW(nt->ndev, qp_num);
+
+	qp = &nt->qps[qp_num];
+	qp->qp_num = qp_num;
+	qp->transport = nt;
+	qp->ndev = nt->ndev;
+	qp->qp_link = NTB_LINK_DOWN;
+	qp->client_ready = NTB_LINK_DOWN;
+	qp->event_handler = NULL;
+
+	if (nt->max_qps % mw_max && mw_num + 1 < nt->max_qps / mw_max)
+		num_qps_mw = nt->max_qps / mw_max + 1;
+	else
+		num_qps_mw = nt->max_qps / mw_max;
+
+	tx_size = (unsigned int) ntb_get_mw_size(qp->ndev, mw_num) / num_qps_mw;
+	qp_offset = qp_num / mw_max * tx_size;
+	qp->tx_mw = ntb_get_mw_vbase(nt->ndev, mw_num) + qp_offset;
+	if (!qp->tx_mw)
+		return -EINVAL;
+
+	qp->tx_mw_phys = ntb_get_mw_base(qp->ndev, mw_num) + 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 (ntb_query_debugfs(nt->ndev)) {
+		char debugfs_name[4];
+
+		snprintf(debugfs_name, 4, "qp%d", qp_num);
+		qp->debugfs_dir = debugfs_create_dir(debugfs_name,
+						 ntb_query_debugfs(nt->ndev));
+
+		qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
+							qp->debugfs_dir, qp,
+							&ntb_qp_debugfs_stats);
+	}
+
+	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_pend_q_lock);
+	spin_lock_init(&qp->ntb_rx_free_q_lock);
+	spin_lock_init(&qp->ntb_tx_free_q_lock);
+
+	INIT_LIST_HEAD(&qp->rx_pend_q);
+	INIT_LIST_HEAD(&qp->rx_free_q);
+	INIT_LIST_HEAD(&qp->tx_free_q);
+
+	return 0;
+}
+
+int ntb_transport_init(struct pci_dev *pdev)
+{
+	struct ntb_transport *nt;
+	int rc, i;
+
+	nt = kzalloc(sizeof(struct ntb_transport), GFP_KERNEL);
+	if (!nt)
+		return -ENOMEM;
+
+	nt->ndev = ntb_register_transport(pdev, nt);
+	if (!nt->ndev) {
+		rc = -EIO;
+		goto err;
+	}
+
+	nt->mw = kcalloc(ntb_max_mw(nt->ndev), sizeof(struct ntb_transport_mw),
+			 GFP_KERNEL);
+	if (!nt->mw) {
+		rc = -ENOMEM;
+		goto err1;
+	}
+
+	if (max_num_clients)
+		nt->max_qps = min(ntb_max_cbs(nt->ndev), max_num_clients);
+	else
+		nt->max_qps = min(ntb_max_cbs(nt->ndev), ntb_max_mw(nt->ndev));
+
+	nt->qps = kcalloc(nt->max_qps, sizeof(struct ntb_transport_qp),
+			  GFP_KERNEL);
+	if (!nt->qps) {
+		rc = -ENOMEM;
+		goto err2;
+	}
+
+	nt->qp_bitmap = ((u64) 1 << nt->max_qps) - 1;
+
+	for (i = 0; i < nt->max_qps; i++) {
+		rc = ntb_transport_init_queue(nt, i);
+		if (rc)
+			goto err3;
+	}
+
+	INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work);
+	INIT_WORK(&nt->link_cleanup, ntb_transport_link_cleanup_work);
+
+	rc = ntb_register_event_callback(nt->ndev,
+					 ntb_transport_event_callback);
+	if (rc)
+		goto err3;
+
+	INIT_LIST_HEAD(&nt->client_devs);
+	rc = ntb_bus_init(nt);
+	if (rc)
+		goto err4;
+
+	if (ntb_hw_link_status(nt->ndev))
+		schedule_delayed_work(&nt->link_work, 0);
+
+	return 0;
+
+err4:
+	ntb_unregister_event_callback(nt->ndev);
+err3:
+	kfree(nt->qps);
+err2:
+	kfree(nt->mw);
+err1:
+	ntb_unregister_transport(nt->ndev);
+err:
+	kfree(nt);
+	return rc;
+}
+
+void ntb_transport_free(void *transport)
+{
+	struct ntb_transport *nt = transport;
+	struct ntb_device *ndev = nt->ndev;
+	int i;
+
+	ntb_transport_link_cleanup(nt);
+
+	/* verify that all the qp's are freed */
+	for (i = 0; i < nt->max_qps; i++) {
+		if (!test_bit(i, &nt->qp_bitmap))
+			ntb_transport_free_queue(&nt->qps[i]);
+		debugfs_remove_recursive(nt->qps[i].debugfs_dir);
+	}
+
+	ntb_bus_remove(nt);
+
+	cancel_delayed_work_sync(&nt->link_work);
+
+	ntb_unregister_event_callback(ndev);
+
+	for (i = 0; i < ntb_max_mw(ndev); i++)
+		ntb_free_mw(nt, i);
+
+	kfree(nt->qps);
+	kfree(nt->mw);
+	ntb_unregister_transport(ndev);
+	kfree(nt);
+}
+
+static void ntb_rx_copy_callback(void *data)
+{
+	struct ntb_queue_entry *entry = data;
+	struct ntb_transport_qp *qp = entry->qp;
+	void *cb_data = entry->cb_data;
+	unsigned int len = entry->len;
+	struct ntb_payload_header *hdr = entry->rx_hdr;
+
+	/* Ensure that the data is fully copied out before clearing the flag */
+	wmb();
+	hdr->flags = 0;
+
+	iowrite32(entry->index, &qp->rx_info->entry);
+
+	ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry, &qp->rx_free_q);
+
+	if (qp->rx_handler && qp->client_ready == NTB_LINK_UP)
+		qp->rx_handler(qp, qp->cb_data, cb_data, len);
+}
+
+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);
+
+	ntb_rx_copy_callback(entry);
+}
+
+static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset,
+			 size_t len)
+{
+	struct dma_async_tx_descriptor *txd;
+	struct ntb_transport_qp *qp = entry->qp;
+	struct dma_chan *chan = qp->dma_chan;
+	struct dma_device *device;
+	size_t pay_off, buff_off;
+	struct dmaengine_unmap_data *unmap;
+	dma_cookie_t cookie;
+	void *buf = entry->buf;
+
+	entry->len = len;
+
+	if (!chan)
+		goto err;
+
+	if (len < copy_bytes)
+		goto err_wait;
+
+	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_wait;
+
+	unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOWAIT);
+	if (!unmap)
+		goto err_wait;
+
+	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 = 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;
+
+err_set_unmap:
+	dmaengine_unmap_put(unmap);
+err_get_unmap:
+	dmaengine_unmap_put(unmap);
+err_wait:
+	/* If the callbacks come out of order, the writing of the index to the
+	 * last completed will be out of order.  This may result in the
+	 * receive stalling forever.
+	 */
+	dma_sync_wait(chan, qp->last_cookie);
+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);
+
+	entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
+	if (!entry) {
+		dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
+			"no buffer - HDR ver %u, len %d, flags %x\n",
+			hdr->ver, hdr->len, hdr->flags);
+		qp->rx_err_no_buf++;
+		return -ENOMEM;
+	}
+
+	if (!(hdr->flags & DESC_DONE_FLAG)) {
+		ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
+			     &qp->rx_pend_q);
+		qp->rx_ring_empty++;
+		return -EAGAIN;
+	}
+
+	if (hdr->ver != (u32) qp->rx_pkts) {
+		dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
+			"qp %d: version mismatch, expected %llu - got %u\n",
+			qp->qp_num, qp->rx_pkts, hdr->ver);
+		ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
+			     &qp->rx_pend_q);
+		qp->rx_err_ver++;
+		return -EIO;
+	}
+
+	if (hdr->flags & LINK_DOWN_FLAG) {
+		ntb_qp_link_down(qp);
+
+		goto err;
+	}
+
+	dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
+		"rx offset %u, ver %u - %d payload received, buf size %d\n",
+		qp->rx_index, hdr->ver, hdr->len, entry->len);
+
+	qp->rx_bytes += hdr->len;
+	qp->rx_pkts++;
+
+	if (hdr->len > entry->len) {
+		qp->rx_err_oflow++;
+		dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
+			"RX overflow! Wanted %d got %d\n",
+			hdr->len, entry->len);
+
+		goto err;
+	}
+
+	entry->index = qp->rx_index;
+	entry->rx_hdr = hdr;
+
+	ntb_async_rx(entry, offset, hdr->len);
+
+out:
+	qp->rx_index++;
+	qp->rx_index %= qp->rx_max_entry;
+
+	return 0;
+
+err:
+	ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry, &qp->rx_pend_q);
+	/* Ensure that the data is fully copied out before clearing the flag */
+	wmb();
+	hdr->flags = 0;
+	iowrite32(qp->rx_index, &qp->rx_info->entry);
+
+	goto out;
+}
+
+static int ntb_transport_rxc_db(void *data, int db_num)
+{
+	struct ntb_transport_qp *qp = data;
+	int rc, i;
+
+	dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "%s: doorbell %d received\n",
+		__func__, db_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 (qp->dma_chan)
+		dma_async_issue_pending(qp->dma_chan);
+
+	return i;
+}
+
+static void ntb_tx_copy_callback(void *data)
+{
+	struct ntb_queue_entry *entry = data;
+	struct ntb_transport_qp *qp = entry->qp;
+	struct ntb_payload_header __iomem *hdr = entry->tx_hdr;
+
+	/* Ensure that the data is fully copied out before setting the flags */
+	wmb();
+	iowrite32(entry->flags | DESC_DONE_FLAG, &hdr->flags);
+
+	ntb_ring_doorbell(qp->ndev, 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)
+{
+	memcpy_toio(offset, entry->buf, entry->len);
+
+	ntb_tx_copy_callback(entry);
+}
+
+static void ntb_async_tx(struct ntb_transport_qp *qp,
+			 struct ntb_queue_entry *entry)
+{
+	struct ntb_payload_header __iomem *hdr;
+	struct dma_async_tx_descriptor *txd;
+	struct dma_chan *chan = qp->dma_chan;
+	struct dma_device *device;
+	size_t dest_off, buff_off;
+	struct dmaengine_unmap_data *unmap;
+	dma_addr_t dest;
+	dma_cookie_t cookie;
+	void __iomem *offset;
+	size_t len = entry->len;
+	void *buf = entry->buf;
+
+	offset = qp->tx_mw + qp->tx_max_frame * qp->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 (len < copy_bytes)
+		goto err;
+
+	device = chan->device;
+	dest = qp->tx_mw_phys + qp->tx_max_frame * qp->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 = 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);
+	qp->tx_async++;
+
+	return;
+err_set_unmap:
+	dmaengine_unmap_put(unmap);
+err_get_unmap:
+	dmaengine_unmap_put(unmap);
+err:
+	ntb_memcpy_tx(entry, offset);
+	qp->tx_memcpy++;
+}
+
+static int ntb_process_tx(struct ntb_transport_qp *qp,
+			  struct ntb_queue_entry *entry)
+{
+	dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "%lld - tx %u, entry len %d flags %x buff %p\n",
+		qp->tx_pkts, qp->tx_index, entry->len, entry->flags,
+		entry->buf);
+	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->cb_data, qp, 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 = ntb_query_pdev(qp->ndev);
+	struct ntb_queue_entry *entry;
+	int i, rc;
+
+	if (qp->qp_link == NTB_LINK_DOWN)
+		return;
+
+	qp->qp_link = NTB_LINK_DOWN;
+	dev_info(&pdev->dev, "qp %d: 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_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 pci_dev *pdev,
+			   const struct ntb_queue_handlers *handlers)
+{
+	struct ntb_queue_entry *entry;
+	struct ntb_transport_qp *qp;
+	struct ntb_transport *nt;
+	unsigned int free_queue;
+	int rc, i;
+
+	nt = ntb_find_transport(pdev);
+	if (!nt)
+		goto err;
+
+	free_queue = ffs(nt->qp_bitmap);
+	if (!free_queue)
+		goto err;
+
+	/* decrement free_queue to make it zero based */
+	free_queue--;
+
+	clear_bit(free_queue, &nt->qp_bitmap);
+
+	qp = &nt->qps[free_queue];
+	qp->cb_data = data;
+	qp->rx_handler = handlers->rx_handler;
+	qp->tx_handler = handlers->tx_handler;
+	qp->event_handler = handlers->event_handler;
+
+	dmaengine_get();
+	qp->dma_chan = dma_find_channel(DMA_MEMCPY);
+	if (!qp->dma_chan) {
+		dmaengine_put();
+		dev_info(&pdev->dev, "Unable to allocate DMA channel, using CPU instead\n");
+	}
+
+	for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
+		entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC);
+		if (!entry)
+			goto err1;
+
+		entry->qp = qp;
+		ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry,
+			     &qp->rx_free_q);
+	}
+
+	for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
+		entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC);
+		if (!entry)
+			goto err2;
+
+		entry->qp = qp;
+		ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
+			     &qp->tx_free_q);
+	}
+
+	rc = ntb_register_db_callback(qp->ndev, free_queue, qp,
+				      ntb_transport_rxc_db);
+	if (rc)
+		goto err2;
+
+	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:
+	while ((entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
+		kfree(entry);
+	if (qp->dma_chan)
+		dmaengine_put();
+	set_bit(free_queue, &nt->qp_bitmap);
+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;
+
+	if (!qp)
+		return;
+
+	pdev = ntb_query_pdev(qp->ndev);
+
+	if (qp->dma_chan) {
+		struct dma_chan *chan = qp->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->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);
+		dmaengine_put();
+	}
+
+	ntb_unregister_db_callback(qp->ndev, qp->qp_num);
+
+	cancel_delayed_work_sync(&qp->link_work);
+
+	while ((entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
+		kfree(entry);
+
+	while ((entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q))) {
+		dev_warn(&pdev->dev, "Freeing item from a non-empty queue\n");
+		kfree(entry);
+	}
+
+	while ((entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
+		kfree(entry);
+
+	set_bit(qp->qp_num, &qp->transport->qp_bitmap);
+
+	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 == NTB_LINK_UP)
+		return NULL;
+
+	entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
+	if (!entry)
+		return NULL;
+
+	buf = entry->cb_data;
+	*len = entry->len;
+
+	ntb_list_add(&qp->ntb_rx_free_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_free_q_lock, &qp->rx_free_q);
+	if (!entry)
+		return -ENOMEM;
+
+	entry->cb_data = cb;
+	entry->buf = data;
+	entry->len = len;
+
+	ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry, &qp->rx_pend_q);
+
+	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 || qp->qp_link != NTB_LINK_UP || !len)
+		return -EINVAL;
+
+	entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
+	if (!entry) {
+		qp->tx_err_no_buf++;
+		return -ENOMEM;
+	}
+
+	entry->cb_data = cb;
+	entry->buf = data;
+	entry->len = len;
+	entry->flags = 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 = NTB_LINK_UP;
+
+	if (qp->transport->transport_link == NTB_LINK_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)
+{
+	struct pci_dev *pdev;
+	int rc, val;
+
+	if (!qp)
+		return;
+
+	pdev = ntb_query_pdev(qp->ndev);
+	qp->client_ready = NTB_LINK_DOWN;
+
+	rc = ntb_read_local_spad(qp->ndev, QP_LINKS, &val);
+	if (rc) {
+		dev_err(&pdev->dev, "Error reading spad %d\n", QP_LINKS);
+		return;
+	}
+
+	rc = ntb_write_remote_spad(qp->ndev, QP_LINKS,
+				   val & ~(1 << qp->qp_num));
+	if (rc)
+		dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
+			val & ~(1 << qp->qp_num), QP_LINKS);
+
+	if (qp->qp_link == NTB_LINK_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->qp_link == NTB_LINK_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;
+
+	if (!qp)
+		return 0;
+
+	if (!qp->dma_chan)
+		return qp->tx_max_frame - sizeof(struct ntb_payload_header);
+
+	/* If DMA engine usage is possible, try to find the max size for that */
+	max = qp->tx_max_frame - sizeof(struct ntb_payload_header);
+	max -= max % (1 << qp->dma_chan->device->copy_align);
+
+	return max;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_max_size);