NTB: Split ntb_hw_intel and ntb_transport drivers

Change ntb_hw_intel to use the new NTB hardware abstraction layer.

Split ntb_transport into its own driver.  Change it to use the new NTB
hardware abstraction layer.

Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

1 files changed, 547 insertions, 389 deletions

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index c5f26cda9f97..9faf1c6029af 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -5,6 +5,7 @@
  *   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
@@ -13,6 +14,7 @@
  *   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
@@ -40,7 +42,7 @@
  *   (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
+ * PCIe NTB Transport Linux driver
  *
  * Contact Information:
  * Jon Mason <jon.mason@intel.com>
@@ -56,9 +58,22 @@
 #include <linux/pci.h>
 #include <linux/slab.h>
 #include <linux/types.h>
-#include "hw/intel/ntb_hw_intel.h"
+#include "linux/ntb.h"
+#include "linux/ntb_transport.h"
 
-#define NTB_TRANSPORT_VERSION	3
+#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"
+
+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 = 0x401E;
 module_param(transport_mtu, uint, 0644);
@@ -72,10 +87,12 @@ 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 struct dentry *nt_debugfs_dir;
+
 struct ntb_queue_entry {
 	/* ntb_queue list reference */
 	struct list_head entry;
-	/* pointers to data to be transfered */
+	/* pointers to data to be transferred */
 	void *cb_data;
 	void *buf;
 	unsigned int len;
@@ -94,14 +111,16 @@ struct ntb_rx_info {
 };
 
 struct ntb_transport_qp {
-	struct ntb_transport *transport;
-	struct ntb_device *ndev;
+	struct ntb_transport_ctx *transport;
+	struct ntb_dev *ndev;
 	void *cb_data;
 	struct dma_chan *dma_chan;
 
 	bool client_ready;
-	bool qp_link;
+	bool link_is_up;
+
 	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;
@@ -127,6 +146,7 @@ struct ntb_transport_qp {
 	unsigned int rx_max_entry;
 	unsigned int rx_max_frame;
 	dma_cookie_t last_cookie;
+	struct tasklet_struct rxc_db_work;
 
 	void (*event_handler)(void *data, int status);
 	struct delayed_work link_work;
@@ -153,33 +173,44 @@ struct ntb_transport_qp {
 };
 
 struct ntb_transport_mw {
-	size_t size;
+	phys_addr_t phys_addr;
+	resource_size_t phys_size;
+	resource_size_t xlat_align;
+	resource_size_t xlat_align_size;
+	void __iomem *vbase;
+	size_t xlat_size;
+	size_t buff_size;
 	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 {
+struct ntb_transport_ctx {
 	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 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 link_is_up;
 	struct delayed_work link_work;
 	struct work_struct link_cleanup;
 };
 
 enum {
-	DESC_DONE_FLAG = 1 << 0,
-	LINK_DOWN_FLAG = 1 << 1,
+	DESC_DONE_FLAG = BIT(0),
+	LINK_DOWN_FLAG = BIT(1),
 };
 
 struct ntb_payload_header {
@@ -200,68 +231,69 @@ enum {
 	MAX_SPAD,
 };
 
-#define QP_TO_MW(ndev, qp)	((qp) % ntb_max_mw(ndev))
+#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 int ntb_match_bus(struct device *dev, struct device_driver *drv)
+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_transport_bus_match(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)
+static int ntb_transport_bus_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);
+	const struct ntb_transport_client *client;
 	int rc = -EINVAL;
 
 	get_device(dev);
-	if (drv && drv->probe)
-		rc = drv->probe(pdev);
+
+	client = drv_client(dev->driver);
+	rc = client->probe(dev);
 	if (rc)
 		put_device(dev);
 
 	return rc;
 }
 
-static int ntb_client_remove(struct device *dev)
+static int ntb_transport_bus_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);
+	const struct ntb_transport_client *client;
 
-	if (drv && drv->remove)
-		drv->remove(pdev);
+	client = drv_client(dev->driver);
+	client->remove(dev);
 
 	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 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 *nt)
+static int ntb_bus_init(struct ntb_transport_ctx *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)
+static void ntb_bus_remove(struct ntb_transport_ctx *nt)
 {
 	struct ntb_transport_client_dev *client_dev, *cd;
 
@@ -273,29 +305,26 @@ static void ntb_bus_remove(struct ntb_transport *nt)
 	}
 
 	list_del(&nt->entry);
-
-	if (list_empty(&ntb_transport_list))
-		bus_unregister(&ntb_bus_type);
 }
 
-static void ntb_client_release(struct device *dev)
+static void ntb_transport_client_release(struct device *dev)
 {
 	struct ntb_transport_client_dev *client_dev;
-	client_dev = container_of(dev, struct ntb_transport_client_dev, dev);
 
+	client_dev = dev_client_dev(dev);
 	kfree(client_dev);
 }
 
 /**
- * ntb_unregister_client_dev - Unregister NTB client device
+ * 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_unregister_client_dev(char *device_name)
+void ntb_transport_unregister_client_dev(char *device_name)
 {
 	struct ntb_transport_client_dev *client, *cd;
-	struct ntb_transport *nt;
+	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)
@@ -305,18 +334,18 @@ void ntb_unregister_client_dev(char *device_name)
 				device_unregister(&client->dev);
 			}
 }
-EXPORT_SYMBOL_GPL(ntb_unregister_client_dev);
+EXPORT_SYMBOL_GPL(ntb_transport_unregister_client_dev);
 
 /**
- * ntb_register_client_dev - Register NTB client device
+ * 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_register_client_dev(char *device_name)
+int ntb_transport_register_client_dev(char *device_name)
 {
 	struct ntb_transport_client_dev *client_dev;
-	struct ntb_transport *nt;
+	struct ntb_transport_ctx *nt;
 	int rc, i = 0;
 
 	if (list_empty(&ntb_transport_list))
@@ -325,7 +354,7 @@ int ntb_register_client_dev(char *device_name)
 	list_for_each_entry(nt, &ntb_transport_list, entry) {
 		struct device *dev;
 
-		client_dev = kzalloc(sizeof(struct ntb_transport_client_dev),
+		client_dev = kzalloc(sizeof(*client_dev),
 				     GFP_KERNEL);
 		if (!client_dev) {
 			rc = -ENOMEM;
@@ -336,9 +365,9 @@ int ntb_register_client_dev(char *device_name)
 
 		/* 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;
+		dev->bus = &ntb_transport_bus;
+		dev->release = ntb_transport_client_release;
+		dev->parent = &nt->ndev->dev;
 
 		rc = device_register(dev);
 		if (rc) {
@@ -353,11 +382,11 @@ int ntb_register_client_dev(char *device_name)
 	return 0;
 
 err:
-	ntb_unregister_client_dev(device_name);
+	ntb_transport_unregister_client_dev(device_name);
 
 	return rc;
 }
-EXPORT_SYMBOL_GPL(ntb_register_client_dev);
+EXPORT_SYMBOL_GPL(ntb_transport_register_client_dev);
 
 /**
  * ntb_transport_register_client - Register NTB client driver
@@ -367,9 +396,9 @@ EXPORT_SYMBOL_GPL(ntb_register_client_dev);
  *
  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
  */
-int ntb_transport_register_client(struct ntb_client *drv)
+int ntb_transport_register_client(struct ntb_transport_client *drv)
 {
-	drv->driver.bus = &ntb_bus_type;
+	drv->driver.bus = &ntb_transport_bus;
 
 	if (list_empty(&ntb_transport_list))
 		return -ENODEV;
@@ -386,7 +415,7 @@ EXPORT_SYMBOL_GPL(ntb_transport_register_client);
  *
  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
  */
-void ntb_transport_unregister_client(struct ntb_client *drv)
+void ntb_transport_unregister_client(struct ntb_transport_client *drv)
 {
 	driver_unregister(&drv->driver);
 }
@@ -452,8 +481,8 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
 			       "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");
+			       "\nQP Link %s\n",
+			       qp->link_is_up ? "Up" : "Down");
 	if (out_offset > out_count)
 		out_offset = out_count;
 
@@ -497,26 +526,31 @@ out:
 	return entry;
 }
 
-static void ntb_transport_setup_qp_mw(struct ntb_transport *nt,
-				      unsigned int qp_num)
+static int ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt,
+				     unsigned int qp_num)
 {
-	struct ntb_transport_qp *qp = &nt->qps[qp_num];
+	struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
+	struct ntb_transport_mw *mw;
 	unsigned int rx_size, num_qps_mw;
-	u8 mw_num, mw_max;
+	unsigned int mw_num, mw_count, qp_count;
 	unsigned int i;
 
-	mw_max = ntb_max_mw(nt->ndev);
-	mw_num = QP_TO_MW(nt->ndev, qp_num);
+	mw_count = nt->mw_count;
+	qp_count = nt->qp_count;
 
-	WARN_ON(nt->mw[mw_num].virt_addr == NULL);
+	mw_num = QP_TO_MW(nt, qp_num);
+	mw = &nt->mw_vec[mw_num];
+
+	if (!mw->virt_addr)
+		return -ENOMEM;
 
-	if (nt->max_qps % mw_max && mw_num + 1 < nt->max_qps / mw_max)
-		num_qps_mw = nt->max_qps / mw_max + 1;
+	if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
+		num_qps_mw = qp_count / mw_count + 1;
 	else
-		num_qps_mw = nt->max_qps / mw_max;
+		num_qps_mw = qp_count / mw_count;
 
-	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 = (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;
@@ -530,49 +564,63 @@ static void ntb_transport_setup_qp_mw(struct ntb_transport *nt,
 
 	/* 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);
+		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 void ntb_free_mw(struct ntb_transport *nt, int num_mw)
+static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
 {
-	struct ntb_transport_mw *mw = &nt->mw[num_mw];
-	struct pci_dev *pdev = ntb_query_pdev(nt->ndev);
+	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
+	struct pci_dev *pdev = nt->ndev->pdev;
 
 	if (!mw->virt_addr)
 		return;
 
-	dma_free_coherent(&pdev->dev, mw->size, mw->virt_addr, mw->dma_addr);
+	ntb_mw_clear_trans(nt->ndev, num_mw);
+	dma_free_coherent(&pdev->dev, mw->buff_size,
+			  mw->virt_addr, mw->dma_addr);
+	mw->xlat_size = 0;
+	mw->buff_size = 0;
 	mw->virt_addr = NULL;
 }
 
-static int ntb_set_mw(struct ntb_transport *nt, int num_mw, unsigned int size)
+static int ntb_set_mw(struct ntb_transport_ctx *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);
+	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
+	struct pci_dev *pdev = nt->ndev->pdev;
+	unsigned int xlat_size, buff_size;
+	int rc;
+
+	xlat_size = round_up(size, mw->xlat_align_size);
+	buff_size = round_up(size, mw->xlat_align);
 
 	/* No need to re-setup */
-	if (mw->size == ALIGN(size, 4096))
+	if (mw->xlat_size == xlat_size)
 		return 0;
 
-	if (mw->size != 0)
+	if (mw->buff_size)
 		ntb_free_mw(nt, num_mw);
 
-	/* Alloc memory for receiving data.  Must be 4k aligned */
-	mw->size = ALIGN(size, 4096);
+	/* Alloc memory for receiving data.  Must be aligned */
+	mw->xlat_size = xlat_size;
+	mw->buff_size = buff_size;
 
-	mw->virt_addr = dma_alloc_coherent(&pdev->dev, mw->size, &mw->dma_addr,
-					   GFP_KERNEL);
+	mw->virt_addr = dma_alloc_coherent(&pdev->dev, buff_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);
+		mw->xlat_size = 0;
+		mw->buff_size = 0;
+		dev_err(&pdev->dev, "Unable to alloc MW buff of size %d\n",
+			buff_size);
 		return -ENOMEM;
 	}
 
@@ -582,34 +630,39 @@ static int ntb_set_mw(struct ntb_transport *nt, int num_mw, unsigned int size)
 	 * 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",
+	if (!IS_ALIGNED(mw->dma_addr, mw->xlat_align)) {
+		dev_err(&pdev->dev, "DMA memory %pad is not aligned\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);
+	rc = ntb_mw_set_trans(nt->ndev, 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_cleanup(struct ntb_transport_qp *qp)
 {
-	struct ntb_transport *nt = qp->transport;
-	struct pci_dev *pdev = ntb_query_pdev(nt->ndev);
+	struct ntb_transport_ctx *nt = qp->transport;
+	struct pci_dev *pdev = nt->ndev->pdev;
 
-	if (qp->qp_link == NTB_LINK_DOWN) {
+	if (qp->link_is_up) {
 		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;
+	qp->link_is_up = false;
+
+	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)
@@ -617,11 +670,11 @@ 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;
+	struct ntb_transport_ctx *nt = qp->transport;
 
 	ntb_qp_link_cleanup(qp);
 
-	if (nt->transport_link == NTB_LINK_UP)
+	if (nt->link_is_up)
 		schedule_delayed_work(&qp->link_work,
 				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 }
@@ -631,180 +684,132 @@ 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)
+static void ntb_transport_link_cleanup(struct ntb_transport_ctx *nt)
 {
+	struct ntb_transport_qp *qp;
+	u64 qp_bitmap_alloc;
 	int i;
 
+	qp_bitmap_alloc = nt->qp_bitmap & ~nt->qp_bitmap_free;
+
 	/* 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]);
+	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->transport_link == NTB_LINK_DOWN)
+	if (!nt->link_is_up)
 		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);
+		ntb_spad_write(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);
+	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, enum ntb_hw_event event)
+static void ntb_transport_event_callback(void *data)
 {
-	struct ntb_transport *nt = data;
+	struct ntb_transport_ctx *nt = data;
 
-	switch (event) {
-	case NTB_EVENT_HW_LINK_UP:
+	if (ntb_link_is_up(nt->ndev, NULL, NULL) == 1)
 		schedule_delayed_work(&nt->link_work, 0);
-		break;
-	case NTB_EVENT_HW_LINK_DOWN:
+	else
 		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);
+	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, i;
+	int rc, i, spad;
 
 	/* 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;
-		}
+	for (i = 0; i < nt->mw_count; i++) {
+		size = nt->mw_vec[i].phys_size;
 
-		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;
-		}
-	}
+		if (max_mw_size && size > max_mw_size)
+			size = max_mw_size;
 
-	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;
-	}
+		spad = MW0_SZ_HIGH + (i * 2);
+		ntb_peer_spad_write(ndev, spad, (u32)(size >> 32));
 
-	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;
+		spad = MW0_SZ_LOW + (i * 2);
+		ntb_peer_spad_write(ndev, spad, (u32)size);
 	}
 
-	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;
-	}
+	ntb_peer_spad_write(ndev, NUM_MWS, nt->mw_count);
 
-	/* 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;
-	}
+	ntb_peer_spad_write(ndev, NUM_QPS, nt->qp_count);
 
-	if (val != NTB_TRANSPORT_VERSION)
-		goto out;
-	dev_dbg(&pdev->dev, "Remote version = %d\n", val);
+	ntb_peer_spad_write(ndev, VERSION, NTB_TRANSPORT_VERSION);
 
-	rc = ntb_read_remote_spad(ndev, NUM_QPS, &val);
-	if (rc) {
-		dev_err(&pdev->dev, "Error reading remote spad %d\n", NUM_QPS);
+	/* Query the remote side for its info */
+	val = ntb_peer_spad_read(ndev, VERSION);
+	dev_dbg(&pdev->dev, "Remote version = %d\n", val);
+	if (val != NTB_TRANSPORT_VERSION)
 		goto out;
-	}
 
-	if (val != nt->max_qps)
-		goto out;
+	val = ntb_peer_spad_read(ndev, NUM_QPS);
 	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);
+	if (val != nt->qp_count)
 		goto out;
-	}
 
-	if (val != ntb_max_mw(ndev))
-		goto out;
+	val = ntb_peer_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 < ntb_max_mw(ndev); i++) {
+	for (i = 0; i < nt->mw_count; 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;
-		}
+		val = ntb_peer_spad_read(ndev, MW0_SZ_HIGH + (i * 2));
+		val64 = (u64)val << 32;
 
+		val = ntb_peer_spad_read(ndev, MW0_SZ_LOW + (i * 2));
 		val64 |= val;
 
-		dev_dbg(&pdev->dev, "Remote MW%d size = %llu\n", i, val64);
+		dev_dbg(&pdev->dev, "Remote MW%d size = %#llx\n", i, val64);
 
 		rc = ntb_set_mw(nt, i, val64);
 		if (rc)
 			goto out1;
 	}
 
-	nt->transport_link = NTB_LINK_UP;
+	nt->link_is_up = true;
 
-	for (i = 0; i < nt->max_qps; i++) {
-		struct ntb_transport_qp *qp = &nt->qps[i];
+	for (i = 0; i < nt->qp_count; i++) {
+		struct ntb_transport_qp *qp = &nt->qp_vec[i];
 
 		ntb_transport_setup_qp_mw(nt, i);
 
-		if (qp->client_ready == NTB_LINK_UP)
+		if (qp->client_ready)
 			schedule_delayed_work(&qp->link_work, 0);
 	}
 
 	return;
 
 out1:
-	for (i = 0; i < ntb_max_mw(ndev); i++)
+	for (i = 0; i < nt->mw_count; i++)
 		ntb_free_mw(nt, i);
 out:
-	if (ntb_hw_link_status(ndev))
+	if (ntb_link_is_up(ndev, NULL, NULL) == 1)
 		schedule_delayed_work(&nt->link_work,
 				      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
 }
@@ -814,73 +819,73 @@ 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;
+	struct pci_dev *pdev = qp->ndev->pdev;
+	struct ntb_transport_ctx *nt = qp->transport;
+	int val;
 
-	WARN_ON(nt->transport_link != NTB_LINK_UP);
+	WARN_ON(!nt->link_is_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;
-	}
+	val = ntb_spad_read(nt->ndev, QP_LINKS);
 
-	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);
+	ntb_peer_spad_write(nt->ndev, QP_LINKS, val | BIT(qp->qp_num));
 
 	/* 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);
-
+	ntb_peer_spad_read(nt->ndev, 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;
-
+	if (val & BIT(qp->qp_num)) {
 		dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
+		qp->link_is_up = true;
+
 		if (qp->event_handler)
-			qp->event_handler(qp->cb_data, NTB_LINK_UP);
-	} else if (nt->transport_link == NTB_LINK_UP)
+			qp->event_handler(qp->cb_data, qp->link_is_up);
+	} 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 *nt,
+static int ntb_transport_init_queue(struct ntb_transport_ctx *nt,
 				    unsigned int qp_num)
 {
 	struct ntb_transport_qp *qp;
+	struct ntb_transport_mw *mw;
+	phys_addr_t mw_base;
+	resource_size_t mw_size;
 	unsigned int num_qps_mw, tx_size;
-	u8 mw_num, mw_max;
+	unsigned int mw_num, mw_count, qp_count;
 	u64 qp_offset;
 
-	mw_max = ntb_max_mw(nt->ndev);
-	mw_num = QP_TO_MW(nt->ndev, qp_num);
+	mw_count = nt->mw_count;
+	qp_count = nt->qp_count;
 
-	qp = &nt->qps[qp_num];
+	mw_num = QP_TO_MW(nt, qp_num);
+	mw = &nt->mw_vec[mw_num];
+
+	qp = &nt->qp_vec[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->link_is_up = false;
+	qp->client_ready = false;
 	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;
+	if (qp_count % mw_count && mw_num + 1 < qp_count / mw_count)
+		num_qps_mw = qp_count / mw_count + 1;
 	else
-		num_qps_mw = nt->max_qps / mw_max;
+		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;
 
-	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;
+	tx_size = (unsigned int)mw_size / num_qps_mw;
+	qp_offset = tx_size * qp_num / mw_count;
+
+	qp->tx_mw = nt->mw_vec[mw_num].vbase + qp_offset;
 	if (!qp->tx_mw)
 		return -EINVAL;
 
-	qp->tx_mw_phys = ntb_get_mw_base(qp->ndev, mw_num) + qp_offset;
+	qp->tx_mw_phys = mw_base + qp_offset;
 	if (!qp->tx_mw_phys)
 		return -EINVAL;
 
@@ -891,16 +896,19 @@ static int ntb_transport_init_queue(struct ntb_transport *nt,
 	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)) {
+	if (nt_debugfs_dir) {
 		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));
+						     nt_debugfs_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);
@@ -914,46 +922,84 @@ static int ntb_transport_init_queue(struct ntb_transport *nt,
 	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;
 }
 
-int ntb_transport_init(struct pci_dev *pdev)
+static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
 {
-	struct ntb_transport *nt;
+	struct ntb_transport_ctx *nt;
+	struct ntb_transport_mw *mw;
+	unsigned int mw_count, qp_count;
+	u64 qp_bitmap;
 	int rc, i;
 
-	nt = kzalloc(sizeof(struct ntb_transport), GFP_KERNEL);
+	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");
+
+	nt = kzalloc(sizeof(*nt), GFP_KERNEL);
 	if (!nt)
 		return -ENOMEM;
 
-	nt->ndev = ntb_register_transport(pdev, nt);
-	if (!nt->ndev) {
-		rc = -EIO;
+	nt->ndev = ndev;
+
+	mw_count = ntb_mw_count(ndev);
+
+	nt->mw_count = mw_count;
+
+	nt->mw_vec = kcalloc(mw_count, sizeof(*nt->mw_vec), GFP_KERNEL);
+	if (!nt->mw_vec) {
+		rc = -ENOMEM;
 		goto err;
 	}
 
-	nt->mw = kcalloc(ntb_max_mw(nt->ndev), sizeof(struct ntb_transport_mw),
-			 GFP_KERNEL);
-	if (!nt->mw) {
-		rc = -ENOMEM;
-		goto err1;
+	for (i = 0; i < mw_count; i++) {
+		mw = &nt->mw_vec[i];
+
+		rc = ntb_mw_get_range(ndev, i, &mw->phys_addr, &mw->phys_size,
+				      &mw->xlat_align, &mw->xlat_align_size);
+		if (rc)
+			goto err1;
+
+		mw->vbase = ioremap(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;
 	}
 
-	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));
+	qp_bitmap = ntb_db_valid_mask(ndev);
+
+	qp_count = ilog2(qp_bitmap);
+	if (max_num_clients && max_num_clients < qp_count)
+		qp_count = max_num_clients;
+	else if (mw_count < qp_count)
+		qp_count = 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->qps = kcalloc(nt->max_qps, sizeof(struct ntb_transport_qp),
-			  GFP_KERNEL);
-	if (!nt->qps) {
+	nt->qp_vec = kcalloc(qp_count, sizeof(*nt->qp_vec), GFP_KERNEL);
+	if (!nt->qp_vec) {
 		rc = -ENOMEM;
 		goto err2;
 	}
 
-	nt->qp_bitmap = ((u64) 1 << nt->max_qps) - 1;
-
-	for (i = 0; i < nt->max_qps; i++) {
+	for (i = 0; i < qp_count; i++) {
 		rc = ntb_transport_init_queue(nt, i);
 		if (rc)
 			goto err3;
@@ -962,8 +1008,7 @@ int ntb_transport_init(struct pci_dev *pdev)
 	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);
+	rc = ntb_set_ctx(ndev, nt, &ntb_transport_ops);
 	if (rc)
 		goto err3;
 
@@ -972,51 +1017,61 @@ int ntb_transport_init(struct pci_dev *pdev)
 	if (rc)
 		goto err4;
 
-	if (ntb_hw_link_status(nt->ndev))
-		schedule_delayed_work(&nt->link_work, 0);
+	nt->link_is_up = false;
+	ntb_link_enable(ndev, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
+	ntb_link_event(ndev);
 
 	return 0;
 
 err4:
-	ntb_unregister_event_callback(nt->ndev);
+	ntb_clear_ctx(ndev);
 err3:
-	kfree(nt->qps);
+	kfree(nt->qp_vec);
 err2:
-	kfree(nt->mw);
+	kfree(nt->mw_vec);
 err1:
-	ntb_unregister_transport(nt->ndev);
+	while (i--) {
+		mw = &nt->mw_vec[i];
+		iounmap(mw->vbase);
+	}
 err:
 	kfree(nt);
 	return rc;
 }
 
-void ntb_transport_free(void *transport)
+static void ntb_transport_free(struct ntb_client *self, struct ntb_dev *ndev)
 {
-	struct ntb_transport *nt = transport;
-	struct ntb_device *ndev = nt->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->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);
+	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_bus_remove(nt);
+	ntb_link_disable(ndev);
+	ntb_clear_ctx(ndev);
 
-	cancel_delayed_work_sync(&nt->link_work);
-
-	ntb_unregister_event_callback(ndev);
+	ntb_bus_remove(nt);
 
-	for (i = 0; i < ntb_max_mw(ndev); i++)
+	for (i = nt->mw_count; i--; ) {
 		ntb_free_mw(nt, i);
+		iounmap(nt->mw_vec[i].vbase);
+	}
 
-	kfree(nt->qps);
-	kfree(nt->mw);
-	ntb_unregister_transport(ndev);
+	kfree(nt->qp_vec);
+	kfree(nt->mw_vec);
 	kfree(nt);
 }
 
@@ -1028,15 +1083,13 @@ static void ntb_rx_copy_callback(void *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)
+	if (qp->rx_handler && qp->client_ready)
 		qp->rx_handler(qp, qp->cb_data, cb_data, len);
 }
 
@@ -1047,6 +1100,9 @@ static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset)
 
 	memcpy(buf, offset, len);
 
+	/* Ensure that the data is fully copied out before clearing the flag */
+	wmb();
+
 	ntb_rx_copy_callback(entry);
 }
 
@@ -1071,8 +1127,8 @@ static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset,
 		goto err_wait;
 
 	device = chan->device;
-	pay_off = (size_t) offset & ~PAGE_MASK;
-	buff_off = (size_t) buf & ~PAGE_MASK;
+	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;
@@ -1138,86 +1194,104 @@ static int ntb_process_rxc(struct ntb_transport_qp *qp)
 	struct ntb_payload_header *hdr;
 	struct ntb_queue_entry *entry;
 	void *offset;
+	int rc;
 
 	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;
-	}
+	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)) {
-		ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
-			     &qp->rx_pend_q);
+		dev_dbg(&qp->ndev->pdev->dev, "done flag not set\n");
 		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);
+	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;
+		iowrite32(qp->rx_index, &qp->rx_info->entry);
+		return 0;
+	}
+
+	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;
 	}
 
-	if (hdr->flags & LINK_DOWN_FLAG) {
-		ntb_qp_link_down(qp);
+	entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
+	if (!entry) {
+		dev_dbg(&qp->ndev->pdev->dev, "no receive buffer\n");
+		qp->rx_err_no_buf++;
 
+		rc = -ENOMEM;
 		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",
+		dev_dbg(&qp->ndev->pdev->dev,
+			"receive buffer overflow! Wanted %d got %d\n",
 			hdr->len, entry->len);
+		qp->rx_err_oflow++;
 
+		rc = -EIO;
 		goto err;
 	}
 
+	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->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();
+	/* FIXME: if this syncrhonous update of the rx_index gets ahead of
+	 * asyncrhonous ntb_rx_copy_callback of previous entry, there are three
+	 * scenarios:
+	 *
+	 * 1) The peer might miss this update, but observe the update
+	 * from the memcpy completion callback.  In this case, the buffer will
+	 * not be freed on the peer to be reused for a different packet.  The
+	 * successful rx of a later packet would clear the condition, but the
+	 * condition could persist if several rx fail in a row.
+	 *
+	 * 2) The peer may observe this update before the asyncrhonous copy of
+	 * prior packets is completed.  The peer may overwrite the buffers of
+	 * the prior packets before they are copied.
+	 *
+	 * 3) Both: the peer may observe the update, and then observe the index
+	 * decrement by the asynchronous completion callback.  Who knows what
+	 * badness that will cause.
+	 */
 	hdr->flags = 0;
 	iowrite32(qp->rx_index, &qp->rx_info->entry);
 
-	goto out;
+	return rc;
 }
 
-static int ntb_transport_rxc_db(void *data, int db_num)
+static void ntb_transport_rxc_db(unsigned long data)
 {
-	struct ntb_transport_qp *qp = data;
+	struct ntb_transport_qp *qp = (void *)data;
 	int rc, i;
 
-	dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "%s: doorbell %d received\n",
-		__func__, db_num);
+	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
@@ -1231,7 +1305,21 @@ static int ntb_transport_rxc_db(void *data, int db_num)
 	if (qp->dma_chan)
 		dma_async_issue_pending(qp->dma_chan);
 
-	return i;
+	if (i == qp->rx_max_entry) {
+		/* there is more work to do */
+		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.
+		 */
+		tasklet_schedule(&qp->rxc_db_work);
+	}
 }
 
 static void ntb_tx_copy_callback(void *data)
@@ -1240,11 +1328,9 @@ static void ntb_tx_copy_callback(void *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);
+	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
@@ -1265,6 +1351,9 @@ static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset)
 {
 	memcpy_toio(offset, entry->buf, entry->len);
 
+	/* Ensure that the data is fully copied out before setting the flags */
+	wmb();
+
 	ntb_tx_copy_callback(entry);
 }
 
@@ -1288,7 +1377,7 @@ static void ntb_async_tx(struct ntb_transport_qp *qp,
 	entry->tx_hdr = hdr;
 
 	iowrite32(entry->len, &hdr->len);
-	iowrite32((u32) qp->tx_pkts, &hdr->ver);
+	iowrite32((u32)qp->tx_pkts, &hdr->ver);
 
 	if (!chan)
 		goto err;
@@ -1298,8 +1387,8 @@ static void ntb_async_tx(struct ntb_transport_qp *qp,
 
 	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;
+	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;
@@ -1347,9 +1436,6 @@ err:
 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;
@@ -1376,14 +1462,14 @@ static int ntb_process_tx(struct ntb_transport_qp *qp,
 
 static void ntb_send_link_down(struct ntb_transport_qp *qp)
 {
-	struct pci_dev *pdev = ntb_query_pdev(qp->ndev);
+	struct pci_dev *pdev = qp->ndev->pdev;
 	struct ntb_queue_entry *entry;
 	int i, rc;
 
-	if (qp->qp_link == NTB_LINK_DOWN)
+	if (!qp->link_is_up)
 		return;
 
-	qp->qp_link = NTB_LINK_DOWN;
+	qp->link_is_up = false;
 	dev_info(&pdev->dev, "qp %d: Link Down\n", qp->qp_num);
 
 	for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
@@ -1422,18 +1508,21 @@ static void ntb_send_link_down(struct ntb_transport_qp *qp)
  * RETURNS: pointer to newly created ntb_queue, NULL on error.
  */
 struct ntb_transport_qp *
-ntb_transport_create_queue(void *data, struct pci_dev *pdev,
+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;
-	struct ntb_transport *nt;
+	u64 qp_bit;
 	unsigned int free_queue;
-	int rc, i;
+	int i;
 
-	nt = ntb_find_transport(pdev);
-	if (!nt)
-		goto err;
+	ndev = dev_ntb(client_dev->parent);
+	pdev = ndev->pdev;
+	nt = ndev->ctx;
 
 	free_queue = ffs(nt->qp_bitmap);
 	if (!free_queue)
@@ -1442,9 +1531,11 @@ ntb_transport_create_queue(void *data, struct pci_dev *pdev,
 	/* decrement free_queue to make it zero based */
 	free_queue--;
 
-	clear_bit(free_queue, &nt->qp_bitmap);
+	qp = &nt->qp_vec[free_queue];
+	qp_bit = BIT_ULL(qp->qp_num);
+
+	nt->qp_bitmap_free &= ~qp_bit;
 
-	qp = &nt->qps[free_queue];
 	qp->cb_data = data;
 	qp->rx_handler = handlers->rx_handler;
 	qp->tx_handler = handlers->tx_handler;
@@ -1458,7 +1549,7 @@ ntb_transport_create_queue(void *data, struct pci_dev *pdev,
 	}
 
 	for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
-		entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC);
+		entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
 		if (!entry)
 			goto err1;
 
@@ -1468,7 +1559,7 @@ ntb_transport_create_queue(void *data, struct pci_dev *pdev,
 	}
 
 	for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
-		entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC);
+		entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
 		if (!entry)
 			goto err2;
 
@@ -1477,10 +1568,8 @@ ntb_transport_create_queue(void *data, struct pci_dev *pdev,
 			     &qp->tx_free_q);
 	}
 
-	rc = ntb_register_db_callback(qp->ndev, free_queue, qp,
-				      ntb_transport_rxc_db);
-	if (rc)
-		goto err2;
+	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);
 
@@ -1494,7 +1583,7 @@ err1:
 		kfree(entry);
 	if (qp->dma_chan)
 		dmaengine_put();
-	set_bit(free_queue, &nt->qp_bitmap);
+	nt->qp_bitmap_free |= qp_bit;
 err:
 	return NULL;
 }
@@ -1508,13 +1597,15 @@ EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
  */
 void ntb_transport_free_queue(struct ntb_transport_qp *qp)
 {
+	struct ntb_transport_ctx *nt = qp->transport;
 	struct pci_dev *pdev;
 	struct ntb_queue_entry *entry;
+	u64 qp_bit;
 
 	if (!qp)
 		return;
 
-	pdev = ntb_query_pdev(qp->ndev);
+	pdev = qp->ndev->pdev;
 
 	if (qp->dma_chan) {
 		struct dma_chan *chan = qp->dma_chan;
@@ -1531,10 +1622,18 @@ void ntb_transport_free_queue(struct ntb_transport_qp *qp)
 		dmaengine_put();
 	}
 
-	ntb_unregister_db_callback(qp->ndev, qp->qp_num);
+	qp_bit = BIT_ULL(qp->qp_num);
+
+	ntb_db_set_mask(qp->ndev, qp_bit);
+	tasklet_disable(&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_free_q_lock, &qp->rx_free_q)))
 		kfree(entry);
 
@@ -1546,7 +1645,7 @@ void ntb_transport_free_queue(struct ntb_transport_qp *qp)
 	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);
+	nt->qp_bitmap_free |= qp_bit;
 
 	dev_info(&pdev->dev, "NTB Transport QP %d freed\n", qp->qp_num);
 }
@@ -1567,7 +1666,7 @@ 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)
+	if (!qp || qp->client_ready)
 		return NULL;
 
 	entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
@@ -1636,7 +1735,7 @@ int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
 	struct ntb_queue_entry *entry;
 	int rc;
 
-	if (!qp || qp->qp_link != NTB_LINK_UP || !len)
+	if (!qp || !qp->link_is_up || !len)
 		return -EINVAL;
 
 	entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
@@ -1670,9 +1769,9 @@ void ntb_transport_link_up(struct ntb_transport_qp *qp)
 	if (!qp)
 		return;
 
-	qp->client_ready = NTB_LINK_UP;
+	qp->client_ready = true;
 
-	if (qp->transport->transport_link == NTB_LINK_UP)
+	if (qp->transport->link_is_up)
 		schedule_delayed_work(&qp->link_work, 0);
 }
 EXPORT_SYMBOL_GPL(ntb_transport_link_up);
@@ -1688,27 +1787,20 @@ EXPORT_SYMBOL_GPL(ntb_transport_link_up);
 void ntb_transport_link_down(struct ntb_transport_qp *qp)
 {
 	struct pci_dev *pdev;
-	int rc, val;
+	int val;
 
 	if (!qp)
 		return;
 
-	pdev = ntb_query_pdev(qp->ndev);
-	qp->client_ready = NTB_LINK_DOWN;
+	pdev = qp->ndev->pdev;
+	qp->client_ready = false;
 
-	rc = ntb_read_local_spad(qp->ndev, QP_LINKS, &val);
-	if (rc) {
-		dev_err(&pdev->dev, "Error reading spad %d\n", QP_LINKS);
-		return;
-	}
+	val = ntb_spad_read(qp->ndev, QP_LINKS);
 
-	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);
+	ntb_peer_spad_write(qp->ndev, QP_LINKS,
+			    val & ~BIT(qp->qp_num));
 
-	if (qp->qp_link == NTB_LINK_UP)
+	if (qp->link_is_up)
 		ntb_send_link_down(qp);
 	else
 		cancel_delayed_work_sync(&qp->link_work);
@@ -1728,7 +1820,7 @@ bool ntb_transport_link_query(struct ntb_transport_qp *qp)
 	if (!qp)
 		return false;
 
-	return qp->qp_link == NTB_LINK_UP;
+	return qp->link_is_up;
 }
 EXPORT_SYMBOL_GPL(ntb_transport_link_query);
 
@@ -1774,3 +1866,69 @@ unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp)
 	return max;
 }
 EXPORT_SYMBOL_GPL(ntb_transport_max_size);
+
+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;
+
+	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];
+
+		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;
+
+	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)
+{
+	debugfs_remove_recursive(nt_debugfs_dir);
+
+	ntb_unregister_client(&ntb_transport_client);
+	bus_unregister(&ntb_transport_bus);
+}
+module_exit(ntb_transport_exit);