Initial import

6 files changed, 4122 insertions, 0 deletions

diff --git a/drivers/ntb/Kconfig b/drivers/ntb/Kconfig
new file mode 100644
index 000000000..f69df793d
--- /dev/null
+++ b/drivers/ntb/Kconfig
@@ -0,0 +1,13 @@
+config NTB
+       tristate "Intel Non-Transparent Bridge support"
+       depends on PCI
+       depends on X86
+       help
+        The PCI-E Non-transparent bridge hardware is a point-to-point PCI-E bus
+        connecting 2 systems.  When configured, writes to the device's PCI
+        mapped memory will be mirrored to a buffer on the remote system.  The
+        ntb Linux driver uses this point-to-point communication as a method to
+        transfer data from one system to the other.
+
+        If unsure, say N.
+
diff --git a/drivers/ntb/Makefile b/drivers/ntb/Makefile
new file mode 100644
index 000000000..15cb59fd3
--- /dev/null
+++ b/drivers/ntb/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_NTB) += ntb.o
+
+ntb-objs := ntb_hw.o ntb_transport.o
diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
new file mode 100644
index 000000000..15f9b7c9e
--- /dev/null
+++ b/drivers/ntb/ntb_hw.c
@@ -0,0 +1,1897 @@
+/*
+ * 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/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include "ntb_hw.h"
+#include "ntb_regs.h"
+
+#define NTB_NAME	"Intel(R) PCI-E Non-Transparent Bridge Driver"
+#define NTB_VER		"1.0"
+
+MODULE_DESCRIPTION(NTB_NAME);
+MODULE_VERSION(NTB_VER);
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Intel Corporation");
+
+enum {
+	NTB_CONN_TRANSPARENT = 0,
+	NTB_CONN_B2B,
+	NTB_CONN_RP,
+};
+
+enum {
+	NTB_DEV_USD = 0,
+	NTB_DEV_DSD,
+};
+
+enum {
+	SNB_HW = 0,
+	BWD_HW,
+};
+
+static struct dentry *debugfs_dir;
+
+#define BWD_LINK_RECOVERY_TIME	500
+
+/* Translate memory window 0,1,2 to BAR 2,4,5 */
+#define MW_TO_BAR(mw)	(mw == 0 ? 2 : (mw == 1 ? 4 : 5))
+
+static const struct pci_device_id ntb_pci_tbl[] = {
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_BWD)},
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_JSF)},
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_SNB)},
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_IVT)},
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_B2B_HSX)},
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_PS_JSF)},
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_PS_SNB)},
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_PS_IVT)},
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_PS_HSX)},
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_SS_JSF)},
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_SS_SNB)},
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_SS_IVT)},
+	{PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_NTB_SS_HSX)},
+	{0}
+};
+MODULE_DEVICE_TABLE(pci, ntb_pci_tbl);
+
+static int is_ntb_xeon(struct ntb_device *ndev)
+{
+	switch (ndev->pdev->device) {
+	case PCI_DEVICE_ID_INTEL_NTB_SS_JSF:
+	case PCI_DEVICE_ID_INTEL_NTB_SS_SNB:
+	case PCI_DEVICE_ID_INTEL_NTB_SS_IVT:
+	case PCI_DEVICE_ID_INTEL_NTB_SS_HSX:
+	case PCI_DEVICE_ID_INTEL_NTB_PS_JSF:
+	case PCI_DEVICE_ID_INTEL_NTB_PS_SNB:
+	case PCI_DEVICE_ID_INTEL_NTB_PS_IVT:
+	case PCI_DEVICE_ID_INTEL_NTB_PS_HSX:
+	case PCI_DEVICE_ID_INTEL_NTB_B2B_JSF:
+	case PCI_DEVICE_ID_INTEL_NTB_B2B_SNB:
+	case PCI_DEVICE_ID_INTEL_NTB_B2B_IVT:
+	case PCI_DEVICE_ID_INTEL_NTB_B2B_HSX:
+		return 1;
+	default:
+		return 0;
+	}
+
+	return 0;
+}
+
+static int is_ntb_atom(struct ntb_device *ndev)
+{
+	switch (ndev->pdev->device) {
+	case PCI_DEVICE_ID_INTEL_NTB_B2B_BWD:
+		return 1;
+	default:
+		return 0;
+	}
+
+	return 0;
+}
+
+static void ntb_set_errata_flags(struct ntb_device *ndev)
+{
+	switch (ndev->pdev->device) {
+	/*
+	 * this workaround applies to all platform up to IvyBridge
+	 * Haswell has splitbar support and use a different workaround
+	 */
+	case PCI_DEVICE_ID_INTEL_NTB_SS_JSF:
+	case PCI_DEVICE_ID_INTEL_NTB_SS_SNB:
+	case PCI_DEVICE_ID_INTEL_NTB_SS_IVT:
+	case PCI_DEVICE_ID_INTEL_NTB_SS_HSX:
+	case PCI_DEVICE_ID_INTEL_NTB_PS_JSF:
+	case PCI_DEVICE_ID_INTEL_NTB_PS_SNB:
+	case PCI_DEVICE_ID_INTEL_NTB_PS_IVT:
+	case PCI_DEVICE_ID_INTEL_NTB_PS_HSX:
+	case PCI_DEVICE_ID_INTEL_NTB_B2B_JSF:
+	case PCI_DEVICE_ID_INTEL_NTB_B2B_SNB:
+	case PCI_DEVICE_ID_INTEL_NTB_B2B_IVT:
+	case PCI_DEVICE_ID_INTEL_NTB_B2B_HSX:
+		ndev->wa_flags |= WA_SNB_ERR;
+		break;
+	}
+}
+
+/**
+ * ntb_register_event_callback() - register event callback
+ * @ndev: pointer to ntb_device instance
+ * @func: callback function to register
+ *
+ * This function registers a callback for any HW driver events such as link
+ * up/down, power management notices and etc.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_register_event_callback(struct ntb_device *ndev,
+				void (*func)(void *handle,
+					     enum ntb_hw_event event))
+{
+	if (ndev->event_cb)
+		return -EINVAL;
+
+	ndev->event_cb = func;
+
+	return 0;
+}
+
+/**
+ * ntb_unregister_event_callback() - unregisters the event callback
+ * @ndev: pointer to ntb_device instance
+ *
+ * This function unregisters the existing callback from transport
+ */
+void ntb_unregister_event_callback(struct ntb_device *ndev)
+{
+	ndev->event_cb = NULL;
+}
+
+static void ntb_irq_work(unsigned long data)
+{
+	struct ntb_db_cb *db_cb = (struct ntb_db_cb *)data;
+	int rc;
+
+	rc = db_cb->callback(db_cb->data, db_cb->db_num);
+	if (rc)
+		tasklet_schedule(&db_cb->irq_work);
+	else {
+		struct ntb_device *ndev = db_cb->ndev;
+		unsigned long mask;
+
+		mask = readw(ndev->reg_ofs.ldb_mask);
+		clear_bit(db_cb->db_num * ndev->bits_per_vector, &mask);
+		writew(mask, ndev->reg_ofs.ldb_mask);
+	}
+}
+
+/**
+ * ntb_register_db_callback() - register a callback for doorbell interrupt
+ * @ndev: pointer to ntb_device instance
+ * @idx: doorbell index to register callback, zero based
+ * @data: pointer to be returned to caller with every callback
+ * @func: callback function to register
+ *
+ * This function registers a callback function for the doorbell interrupt
+ * on the primary side. The function will unmask the doorbell as well to
+ * allow interrupt.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_register_db_callback(struct ntb_device *ndev, unsigned int idx,
+			     void *data, int (*func)(void *data, int db_num))
+{
+	unsigned long mask;
+
+	if (idx >= ndev->max_cbs || ndev->db_cb[idx].callback) {
+		dev_warn(&ndev->pdev->dev, "Invalid Index.\n");
+		return -EINVAL;
+	}
+
+	ndev->db_cb[idx].callback = func;
+	ndev->db_cb[idx].data = data;
+	ndev->db_cb[idx].ndev = ndev;
+
+	tasklet_init(&ndev->db_cb[idx].irq_work, ntb_irq_work,
+		     (unsigned long) &ndev->db_cb[idx]);
+
+	/* unmask interrupt */
+	mask = readw(ndev->reg_ofs.ldb_mask);
+	clear_bit(idx * ndev->bits_per_vector, &mask);
+	writew(mask, ndev->reg_ofs.ldb_mask);
+
+	return 0;
+}
+
+/**
+ * ntb_unregister_db_callback() - unregister a callback for doorbell interrupt
+ * @ndev: pointer to ntb_device instance
+ * @idx: doorbell index to register callback, zero based
+ *
+ * This function unregisters a callback function for the doorbell interrupt
+ * on the primary side. The function will also mask the said doorbell.
+ */
+void ntb_unregister_db_callback(struct ntb_device *ndev, unsigned int idx)
+{
+	unsigned long mask;
+
+	if (idx >= ndev->max_cbs || !ndev->db_cb[idx].callback)
+		return;
+
+	mask = readw(ndev->reg_ofs.ldb_mask);
+	set_bit(idx * ndev->bits_per_vector, &mask);
+	writew(mask, ndev->reg_ofs.ldb_mask);
+
+	tasklet_disable(&ndev->db_cb[idx].irq_work);
+
+	ndev->db_cb[idx].callback = NULL;
+}
+
+/**
+ * ntb_find_transport() - find the transport pointer
+ * @transport: pointer to pci device
+ *
+ * Given the pci device pointer, return the transport pointer passed in when
+ * the transport attached when it was inited.
+ *
+ * RETURNS: pointer to transport.
+ */
+void *ntb_find_transport(struct pci_dev *pdev)
+{
+	struct ntb_device *ndev = pci_get_drvdata(pdev);
+	return ndev->ntb_transport;
+}
+
+/**
+ * ntb_register_transport() - Register NTB transport with NTB HW driver
+ * @transport: transport identifier
+ *
+ * This function allows a transport to reserve the hardware driver for
+ * NTB usage.
+ *
+ * RETURNS: pointer to ntb_device, NULL on error.
+ */
+struct ntb_device *ntb_register_transport(struct pci_dev *pdev, void *transport)
+{
+	struct ntb_device *ndev = pci_get_drvdata(pdev);
+
+	if (ndev->ntb_transport)
+		return NULL;
+
+	ndev->ntb_transport = transport;
+	return ndev;
+}
+
+/**
+ * ntb_unregister_transport() - Unregister the transport with the NTB HW driver
+ * @ndev - ntb_device of the transport to be freed
+ *
+ * This function unregisters the transport from the HW driver and performs any
+ * necessary cleanups.
+ */
+void ntb_unregister_transport(struct ntb_device *ndev)
+{
+	int i;
+
+	if (!ndev->ntb_transport)
+		return;
+
+	for (i = 0; i < ndev->max_cbs; i++)
+		ntb_unregister_db_callback(ndev, i);
+
+	ntb_unregister_event_callback(ndev);
+	ndev->ntb_transport = NULL;
+}
+
+/**
+ * ntb_write_local_spad() - write to the secondary scratchpad register
+ * @ndev: pointer to ntb_device instance
+ * @idx: index to the scratchpad register, 0 based
+ * @val: the data value to put into the register
+ *
+ * This function allows writing of a 32bit value to the indexed scratchpad
+ * register. This writes over the data mirrored to the local scratchpad register
+ * by the remote system.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_write_local_spad(struct ntb_device *ndev, unsigned int idx, u32 val)
+{
+	if (idx >= ndev->limits.max_spads)
+		return -EINVAL;
+
+	dev_dbg(&ndev->pdev->dev, "Writing %x to local scratch pad index %d\n",
+		val, idx);
+	writel(val, ndev->reg_ofs.spad_read + idx * 4);
+
+	return 0;
+}
+
+/**
+ * ntb_read_local_spad() - read from the primary scratchpad register
+ * @ndev: pointer to ntb_device instance
+ * @idx: index to scratchpad register, 0 based
+ * @val: pointer to 32bit integer for storing the register value
+ *
+ * This function allows reading of the 32bit scratchpad register on
+ * the primary (internal) side.  This allows the local system to read data
+ * written and mirrored to the scratchpad register by the remote system.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_read_local_spad(struct ntb_device *ndev, unsigned int idx, u32 *val)
+{
+	if (idx >= ndev->limits.max_spads)
+		return -EINVAL;
+
+	*val = readl(ndev->reg_ofs.spad_write + idx * 4);
+	dev_dbg(&ndev->pdev->dev,
+		"Reading %x from local scratch pad index %d\n", *val, idx);
+
+	return 0;
+}
+
+/**
+ * ntb_write_remote_spad() - write to the secondary scratchpad register
+ * @ndev: pointer to ntb_device instance
+ * @idx: index to the scratchpad register, 0 based
+ * @val: the data value to put into the register
+ *
+ * This function allows writing of a 32bit value to the indexed scratchpad
+ * register. The register resides on the secondary (external) side.  This allows
+ * the local system to write data to be mirrored to the remote systems
+ * scratchpad register.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_write_remote_spad(struct ntb_device *ndev, unsigned int idx, u32 val)
+{
+	if (idx >= ndev->limits.max_spads)
+		return -EINVAL;
+
+	dev_dbg(&ndev->pdev->dev, "Writing %x to remote scratch pad index %d\n",
+		val, idx);
+	writel(val, ndev->reg_ofs.spad_write + idx * 4);
+
+	return 0;
+}
+
+/**
+ * ntb_read_remote_spad() - read from the primary scratchpad register
+ * @ndev: pointer to ntb_device instance
+ * @idx: index to scratchpad register, 0 based
+ * @val: pointer to 32bit integer for storing the register value
+ *
+ * This function allows reading of the 32bit scratchpad register on
+ * the primary (internal) side.  This alloows the local system to read the data
+ * it wrote to be mirrored on the remote system.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_read_remote_spad(struct ntb_device *ndev, unsigned int idx, u32 *val)
+{
+	if (idx >= ndev->limits.max_spads)
+		return -EINVAL;
+
+	*val = readl(ndev->reg_ofs.spad_read + idx * 4);
+	dev_dbg(&ndev->pdev->dev,
+		"Reading %x from remote scratch pad index %d\n", *val, idx);
+
+	return 0;
+}
+
+/**
+ * ntb_get_mw_base() - get addr for the NTB memory window
+ * @ndev: pointer to ntb_device instance
+ * @mw: memory window number
+ *
+ * This function provides the base address of the memory window specified.
+ *
+ * RETURNS: address, or NULL on error.
+ */
+resource_size_t ntb_get_mw_base(struct ntb_device *ndev, unsigned int mw)
+{
+	if (mw >= ntb_max_mw(ndev))
+		return 0;
+
+	return pci_resource_start(ndev->pdev, MW_TO_BAR(mw));
+}
+
+/**
+ * ntb_get_mw_vbase() - get virtual addr for the NTB memory window
+ * @ndev: pointer to ntb_device instance
+ * @mw: memory window number
+ *
+ * This function provides the base virtual address of the memory window
+ * specified.
+ *
+ * RETURNS: pointer to virtual address, or NULL on error.
+ */
+void __iomem *ntb_get_mw_vbase(struct ntb_device *ndev, unsigned int mw)
+{
+	if (mw >= ntb_max_mw(ndev))
+		return NULL;
+
+	return ndev->mw[mw].vbase;
+}
+
+/**
+ * ntb_get_mw_size() - return size of NTB memory window
+ * @ndev: pointer to ntb_device instance
+ * @mw: memory window number
+ *
+ * This function provides the physical size of the memory window specified
+ *
+ * RETURNS: the size of the memory window or zero on error
+ */
+u64 ntb_get_mw_size(struct ntb_device *ndev, unsigned int mw)
+{
+	if (mw >= ntb_max_mw(ndev))
+		return 0;
+
+	return ndev->mw[mw].bar_sz;
+}
+
+/**
+ * ntb_set_mw_addr - set the memory window address
+ * @ndev: pointer to ntb_device instance
+ * @mw: memory window number
+ * @addr: base address for data
+ *
+ * This function sets the base physical address of the memory window.  This
+ * memory address is where data from the remote system will be transfered into
+ * or out of depending on how the transport is configured.
+ */
+void ntb_set_mw_addr(struct ntb_device *ndev, unsigned int mw, u64 addr)
+{
+	if (mw >= ntb_max_mw(ndev))
+		return;
+
+	dev_dbg(&ndev->pdev->dev, "Writing addr %Lx to BAR %d\n", addr,
+		MW_TO_BAR(mw));
+
+	ndev->mw[mw].phys_addr = addr;
+
+	switch (MW_TO_BAR(mw)) {
+	case NTB_BAR_23:
+		writeq(addr, ndev->reg_ofs.bar2_xlat);
+		break;
+	case NTB_BAR_4:
+		if (ndev->split_bar)
+			writel(addr, ndev->reg_ofs.bar4_xlat);
+		else
+			writeq(addr, ndev->reg_ofs.bar4_xlat);
+		break;
+	case NTB_BAR_5:
+		writel(addr, ndev->reg_ofs.bar5_xlat);
+		break;
+	}
+}
+
+/**
+ * ntb_ring_doorbell() - Set the doorbell on the secondary/external side
+ * @ndev: pointer to ntb_device instance
+ * @db: doorbell to ring
+ *
+ * This function allows triggering of a doorbell on the secondary/external
+ * side that will initiate an interrupt on the remote host
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+void ntb_ring_doorbell(struct ntb_device *ndev, unsigned int db)
+{
+	dev_dbg(&ndev->pdev->dev, "%s: ringing doorbell %d\n", __func__, db);
+
+	if (ndev->hw_type == BWD_HW)
+		writeq((u64) 1 << db, ndev->reg_ofs.rdb);
+	else
+		writew(((1 << ndev->bits_per_vector) - 1) <<
+		       (db * ndev->bits_per_vector), ndev->reg_ofs.rdb);
+}
+
+static void bwd_recover_link(struct ntb_device *ndev)
+{
+	u32 status;
+
+	/* Driver resets the NTB ModPhy lanes - magic! */
+	writeb(0xe0, ndev->reg_base + BWD_MODPHY_PCSREG6);
+	writeb(0x40, ndev->reg_base + BWD_MODPHY_PCSREG4);
+	writeb(0x60, ndev->reg_base + BWD_MODPHY_PCSREG4);
+	writeb(0x60, ndev->reg_base + BWD_MODPHY_PCSREG6);
+
+	/* Driver waits 100ms to allow the NTB ModPhy to settle */
+	msleep(100);
+
+	/* Clear AER Errors, write to clear */
+	status = readl(ndev->reg_base + BWD_ERRCORSTS_OFFSET);
+	dev_dbg(&ndev->pdev->dev, "ERRCORSTS = %x\n", status);
+	status &= PCI_ERR_COR_REP_ROLL;
+	writel(status, ndev->reg_base + BWD_ERRCORSTS_OFFSET);
+
+	/* Clear unexpected electrical idle event in LTSSM, write to clear */
+	status = readl(ndev->reg_base + BWD_LTSSMERRSTS0_OFFSET);
+	dev_dbg(&ndev->pdev->dev, "LTSSMERRSTS0 = %x\n", status);
+	status |= BWD_LTSSMERRSTS0_UNEXPECTEDEI;
+	writel(status, ndev->reg_base + BWD_LTSSMERRSTS0_OFFSET);
+
+	/* Clear DeSkew Buffer error, write to clear */
+	status = readl(ndev->reg_base + BWD_DESKEWSTS_OFFSET);
+	dev_dbg(&ndev->pdev->dev, "DESKEWSTS = %x\n", status);
+	status |= BWD_DESKEWSTS_DBERR;
+	writel(status, ndev->reg_base + BWD_DESKEWSTS_OFFSET);
+
+	status = readl(ndev->reg_base + BWD_IBSTERRRCRVSTS0_OFFSET);
+	dev_dbg(&ndev->pdev->dev, "IBSTERRRCRVSTS0 = %x\n", status);
+	status &= BWD_IBIST_ERR_OFLOW;
+	writel(status, ndev->reg_base + BWD_IBSTERRRCRVSTS0_OFFSET);
+
+	/* Releases the NTB state machine to allow the link to retrain */
+	status = readl(ndev->reg_base + BWD_LTSSMSTATEJMP_OFFSET);
+	dev_dbg(&ndev->pdev->dev, "LTSSMSTATEJMP = %x\n", status);
+	status &= ~BWD_LTSSMSTATEJMP_FORCEDETECT;
+	writel(status, ndev->reg_base + BWD_LTSSMSTATEJMP_OFFSET);
+}
+
+static void ntb_link_event(struct ntb_device *ndev, int link_state)
+{
+	unsigned int event;
+
+	if (ndev->link_status == link_state)
+		return;
+
+	if (link_state == NTB_LINK_UP) {
+		u16 status;
+
+		dev_info(&ndev->pdev->dev, "Link Up\n");
+		ndev->link_status = NTB_LINK_UP;
+		event = NTB_EVENT_HW_LINK_UP;
+
+		if (is_ntb_atom(ndev) ||
+		    ndev->conn_type == NTB_CONN_TRANSPARENT)
+			status = readw(ndev->reg_ofs.lnk_stat);
+		else {
+			int rc = pci_read_config_word(ndev->pdev,
+						      SNB_LINK_STATUS_OFFSET,
+						      &status);
+			if (rc)
+				return;
+		}
+
+		ndev->link_width = (status & NTB_LINK_WIDTH_MASK) >> 4;
+		ndev->link_speed = (status & NTB_LINK_SPEED_MASK);
+		dev_info(&ndev->pdev->dev, "Link Width %d, Link Speed %d\n",
+			 ndev->link_width, ndev->link_speed);
+	} else {
+		dev_info(&ndev->pdev->dev, "Link Down\n");
+		ndev->link_status = NTB_LINK_DOWN;
+		event = NTB_EVENT_HW_LINK_DOWN;
+		/* Don't modify link width/speed, we need it in link recovery */
+	}
+
+	/* notify the upper layer if we have an event change */
+	if (ndev->event_cb)
+		ndev->event_cb(ndev->ntb_transport, event);
+}
+
+static int ntb_link_status(struct ntb_device *ndev)
+{
+	int link_state;
+
+	if (is_ntb_atom(ndev)) {
+		u32 ntb_cntl;
+
+		ntb_cntl = readl(ndev->reg_ofs.lnk_cntl);
+		if (ntb_cntl & BWD_CNTL_LINK_DOWN)
+			link_state = NTB_LINK_DOWN;
+		else
+			link_state = NTB_LINK_UP;
+	} else {
+		u16 status;
+		int rc;
+
+		rc = pci_read_config_word(ndev->pdev, SNB_LINK_STATUS_OFFSET,
+					  &status);
+		if (rc)
+			return rc;
+
+		if (status & NTB_LINK_STATUS_ACTIVE)
+			link_state = NTB_LINK_UP;
+		else
+			link_state = NTB_LINK_DOWN;
+	}
+
+	ntb_link_event(ndev, link_state);
+
+	return 0;
+}
+
+static void bwd_link_recovery(struct work_struct *work)
+{
+	struct ntb_device *ndev = container_of(work, struct ntb_device,
+					       lr_timer.work);
+	u32 status32;
+
+	bwd_recover_link(ndev);
+	/* There is a potential race between the 2 NTB devices recovering at the
+	 * same time.  If the times are the same, the link will not recover and
+	 * the driver will be stuck in this loop forever.  Add a random interval
+	 * to the recovery time to prevent this race.
+	 */
+	msleep(BWD_LINK_RECOVERY_TIME + prandom_u32() % BWD_LINK_RECOVERY_TIME);
+
+	status32 = readl(ndev->reg_base + BWD_LTSSMSTATEJMP_OFFSET);
+	if (status32 & BWD_LTSSMSTATEJMP_FORCEDETECT)
+		goto retry;
+
+	status32 = readl(ndev->reg_base + BWD_IBSTERRRCRVSTS0_OFFSET);
+	if (status32 & BWD_IBIST_ERR_OFLOW)
+		goto retry;
+
+	status32 = readl(ndev->reg_ofs.lnk_cntl);
+	if (!(status32 & BWD_CNTL_LINK_DOWN)) {
+		unsigned char speed, width;
+		u16 status16;
+
+		status16 = readw(ndev->reg_ofs.lnk_stat);
+		width = (status16 & NTB_LINK_WIDTH_MASK) >> 4;
+		speed = (status16 & NTB_LINK_SPEED_MASK);
+		if (ndev->link_width != width || ndev->link_speed != speed)
+			goto retry;
+	}
+
+	schedule_delayed_work(&ndev->hb_timer, NTB_HB_TIMEOUT);
+	return;
+
+retry:
+	schedule_delayed_work(&ndev->lr_timer, NTB_HB_TIMEOUT);
+}
+
+/* BWD doesn't have link status interrupt, poll on that platform */
+static void bwd_link_poll(struct work_struct *work)
+{
+	struct ntb_device *ndev = container_of(work, struct ntb_device,
+					       hb_timer.work);
+	unsigned long ts = jiffies;
+
+	/* If we haven't gotten an interrupt in a while, check the BWD link
+	 * status bit
+	 */
+	if (ts > ndev->last_ts + NTB_HB_TIMEOUT) {
+		int rc = ntb_link_status(ndev);
+		if (rc)
+			dev_err(&ndev->pdev->dev,
+				"Error determining link status\n");
+
+		/* Check to see if a link error is the cause of the link down */
+		if (ndev->link_status == NTB_LINK_DOWN) {
+			u32 status32 = readl(ndev->reg_base +
+					     BWD_LTSSMSTATEJMP_OFFSET);
+			if (status32 & BWD_LTSSMSTATEJMP_FORCEDETECT) {
+				schedule_delayed_work(&ndev->lr_timer, 0);
+				return;
+			}
+		}
+	}
+
+	schedule_delayed_work(&ndev->hb_timer, NTB_HB_TIMEOUT);
+}
+
+static int ntb_xeon_setup(struct ntb_device *ndev)
+{
+	switch (ndev->conn_type) {
+	case NTB_CONN_B2B:
+		ndev->reg_ofs.ldb = ndev->reg_base + SNB_PDOORBELL_OFFSET;
+		ndev->reg_ofs.ldb_mask = ndev->reg_base + SNB_PDBMSK_OFFSET;
+		ndev->reg_ofs.spad_read = ndev->reg_base + SNB_SPAD_OFFSET;
+		ndev->reg_ofs.bar2_xlat = ndev->reg_base + SNB_SBAR2XLAT_OFFSET;
+		ndev->reg_ofs.bar4_xlat = ndev->reg_base + SNB_SBAR4XLAT_OFFSET;
+		if (ndev->split_bar)
+			ndev->reg_ofs.bar5_xlat =
+				ndev->reg_base + SNB_SBAR5XLAT_OFFSET;
+		ndev->limits.max_spads = SNB_MAX_B2B_SPADS;
+
+		/* There is a Xeon hardware errata related to writes to
+		 * SDOORBELL or B2BDOORBELL in conjunction with inbound access
+		 * to NTB MMIO Space, which may hang the system.  To workaround
+		 * this use the second memory window to access the interrupt and
+		 * scratch pad registers on the remote system.
+		 */
+		if (ndev->wa_flags & WA_SNB_ERR) {
+			if (!ndev->mw[ndev->limits.max_mw - 1].bar_sz)
+				return -EINVAL;
+
+			ndev->limits.max_db_bits = SNB_MAX_DB_BITS;
+			ndev->reg_ofs.spad_write =
+				ndev->mw[ndev->limits.max_mw - 1].vbase +
+				SNB_SPAD_OFFSET;
+			ndev->reg_ofs.rdb =
+				ndev->mw[ndev->limits.max_mw - 1].vbase +
+				SNB_PDOORBELL_OFFSET;
+
+			/* Set the Limit register to 4k, the minimum size, to
+			 * prevent an illegal access
+			 */
+			writeq(ndev->mw[1].bar_sz + 0x1000, ndev->reg_base +
+			       SNB_PBAR4LMT_OFFSET);
+			/* HW errata on the Limit registers.  They can only be
+			 * written when the base register is 4GB aligned and
+			 * < 32bit.  This should already be the case based on
+			 * the driver defaults, but write the Limit registers
+			 * first just in case.
+			 */
+
+			ndev->limits.max_mw = SNB_ERRATA_MAX_MW;
+		} else {
+			/* HW Errata on bit 14 of b2bdoorbell register.  Writes
+			 * will not be mirrored to the remote system.  Shrink
+			 * the number of bits by one, since bit 14 is the last
+			 * bit.
+			 */
+			ndev->limits.max_db_bits = SNB_MAX_DB_BITS - 1;
+			ndev->reg_ofs.spad_write = ndev->reg_base +
+						   SNB_B2B_SPAD_OFFSET;
+			ndev->reg_ofs.rdb = ndev->reg_base +
+					    SNB_B2B_DOORBELL_OFFSET;
+
+			/* Disable the Limit register, just incase it is set to
+			 * something silly. A 64bit write should handle it
+			 * regardless of whether it has a split BAR or not.
+			 */
+			writeq(0, ndev->reg_base + SNB_PBAR4LMT_OFFSET);
+			/* HW errata on the Limit registers.  They can only be
+			 * written when the base register is 4GB aligned and
+			 * < 32bit.  This should already be the case based on
+			 * the driver defaults, but write the Limit registers
+			 * first just in case.
+			 */
+			if (ndev->split_bar)
+				ndev->limits.max_mw = HSX_SPLITBAR_MAX_MW;
+			else
+				ndev->limits.max_mw = SNB_MAX_MW;
+		}
+
+		/* The Xeon errata workaround requires setting SBAR Base
+		 * addresses to known values, so that the PBAR XLAT can be
+		 * pointed at SBAR0 of the remote system.
+		 */
+		if (ndev->dev_type == NTB_DEV_USD) {
+			writeq(SNB_MBAR23_DSD_ADDR, ndev->reg_base +
+			       SNB_PBAR2XLAT_OFFSET);
+			if (ndev->wa_flags & WA_SNB_ERR)
+				writeq(SNB_MBAR01_DSD_ADDR, ndev->reg_base +
+				       SNB_PBAR4XLAT_OFFSET);
+			else {
+				if (ndev->split_bar) {
+					writel(SNB_MBAR4_DSD_ADDR,
+					       ndev->reg_base +
+					       SNB_PBAR4XLAT_OFFSET);
+					writel(SNB_MBAR5_DSD_ADDR,
+					       ndev->reg_base +
+					       SNB_PBAR5XLAT_OFFSET);
+				} else
+					writeq(SNB_MBAR4_DSD_ADDR,
+					       ndev->reg_base +
+					       SNB_PBAR4XLAT_OFFSET);
+
+				/* B2B_XLAT_OFFSET is a 64bit register, but can
+				 * only take 32bit writes
+				 */
+				writel(SNB_MBAR01_DSD_ADDR & 0xffffffff,
+				       ndev->reg_base + SNB_B2B_XLAT_OFFSETL);
+				writel(SNB_MBAR01_DSD_ADDR >> 32,
+				       ndev->reg_base + SNB_B2B_XLAT_OFFSETU);
+			}
+
+			writeq(SNB_MBAR01_USD_ADDR, ndev->reg_base +
+			       SNB_SBAR0BASE_OFFSET);
+			writeq(SNB_MBAR23_USD_ADDR, ndev->reg_base +
+			       SNB_SBAR2BASE_OFFSET);
+			if (ndev->split_bar) {
+				writel(SNB_MBAR4_USD_ADDR, ndev->reg_base +
+				       SNB_SBAR4BASE_OFFSET);
+				writel(SNB_MBAR5_USD_ADDR, ndev->reg_base +
+				       SNB_SBAR5BASE_OFFSET);
+			} else
+				writeq(SNB_MBAR4_USD_ADDR, ndev->reg_base +
+				       SNB_SBAR4BASE_OFFSET);
+		} else {
+			writeq(SNB_MBAR23_USD_ADDR, ndev->reg_base +
+			       SNB_PBAR2XLAT_OFFSET);
+			if (ndev->wa_flags & WA_SNB_ERR)
+				writeq(SNB_MBAR01_USD_ADDR, ndev->reg_base +
+				       SNB_PBAR4XLAT_OFFSET);
+			else {
+				if (ndev->split_bar) {
+					writel(SNB_MBAR4_USD_ADDR,
+					       ndev->reg_base +
+					       SNB_PBAR4XLAT_OFFSET);
+					writel(SNB_MBAR5_USD_ADDR,
+					       ndev->reg_base +
+					       SNB_PBAR5XLAT_OFFSET);
+				} else
+					writeq(SNB_MBAR4_USD_ADDR,
+					       ndev->reg_base +
+					       SNB_PBAR4XLAT_OFFSET);
+
+				/*
+				 * B2B_XLAT_OFFSET is a 64bit register, but can
+				 * only take 32bit writes
+				 */
+				writel(SNB_MBAR01_USD_ADDR & 0xffffffff,
+				       ndev->reg_base + SNB_B2B_XLAT_OFFSETL);
+				writel(SNB_MBAR01_USD_ADDR >> 32,
+				       ndev->reg_base + SNB_B2B_XLAT_OFFSETU);
+			}
+			writeq(SNB_MBAR01_DSD_ADDR, ndev->reg_base +
+			       SNB_SBAR0BASE_OFFSET);
+			writeq(SNB_MBAR23_DSD_ADDR, ndev->reg_base +
+			       SNB_SBAR2BASE_OFFSET);
+			if (ndev->split_bar) {
+				writel(SNB_MBAR4_DSD_ADDR, ndev->reg_base +
+				       SNB_SBAR4BASE_OFFSET);
+				writel(SNB_MBAR5_DSD_ADDR, ndev->reg_base +
+				       SNB_SBAR5BASE_OFFSET);
+			} else
+				writeq(SNB_MBAR4_DSD_ADDR, ndev->reg_base +
+				       SNB_SBAR4BASE_OFFSET);
+
+		}
+		break;
+	case NTB_CONN_RP:
+		if (ndev->wa_flags & WA_SNB_ERR) {
+			dev_err(&ndev->pdev->dev,
+				"NTB-RP disabled due to hardware errata.\n");
+			return -EINVAL;
+		}
+
+		/* Scratch pads need to have exclusive access from the primary
+		 * or secondary side.  Halve the num spads so that each side can
+		 * have an equal amount.
+		 */
+		ndev->limits.max_spads = SNB_MAX_COMPAT_SPADS / 2;
+		ndev->limits.max_db_bits = SNB_MAX_DB_BITS;
+		/* Note: The SDOORBELL is the cause of the errata.  You REALLY
+		 * don't want to touch it.
+		 */
+		ndev->reg_ofs.rdb = ndev->reg_base + SNB_SDOORBELL_OFFSET;
+		ndev->reg_ofs.ldb = ndev->reg_base + SNB_PDOORBELL_OFFSET;
+		ndev->reg_ofs.ldb_mask = ndev->reg_base + SNB_PDBMSK_OFFSET;
+		/* Offset the start of the spads to correspond to whether it is
+		 * primary or secondary
+		 */
+		ndev->reg_ofs.spad_write = ndev->reg_base + SNB_SPAD_OFFSET +
+					   ndev->limits.max_spads * 4;
+		ndev->reg_ofs.spad_read = ndev->reg_base + SNB_SPAD_OFFSET;
+		ndev->reg_ofs.bar2_xlat = ndev->reg_base + SNB_SBAR2XLAT_OFFSET;
+		ndev->reg_ofs.bar4_xlat = ndev->reg_base + SNB_SBAR4XLAT_OFFSET;
+		if (ndev->split_bar) {
+			ndev->reg_ofs.bar5_xlat =
+				ndev->reg_base + SNB_SBAR5XLAT_OFFSET;
+			ndev->limits.max_mw = HSX_SPLITBAR_MAX_MW;
+		} else
+			ndev->limits.max_mw = SNB_MAX_MW;
+		break;
+	case NTB_CONN_TRANSPARENT:
+		if (ndev->wa_flags & WA_SNB_ERR) {
+			dev_err(&ndev->pdev->dev,
+				"NTB-TRANSPARENT disabled due to hardware errata.\n");
+			return -EINVAL;
+		}
+
+		/* Scratch pads need to have exclusive access from the primary
+		 * or secondary side.  Halve the num spads so that each side can
+		 * have an equal amount.
+		 */
+		ndev->limits.max_spads = SNB_MAX_COMPAT_SPADS / 2;
+		ndev->limits.max_db_bits = SNB_MAX_DB_BITS;
+		ndev->reg_ofs.rdb = ndev->reg_base + SNB_PDOORBELL_OFFSET;
+		ndev->reg_ofs.ldb = ndev->reg_base + SNB_SDOORBELL_OFFSET;
+		ndev->reg_ofs.ldb_mask = ndev->reg_base + SNB_SDBMSK_OFFSET;
+		ndev->reg_ofs.spad_write = ndev->reg_base + SNB_SPAD_OFFSET;
+		/* Offset the start of the spads to correspond to whether it is
+		 * primary or secondary
+		 */
+		ndev->reg_ofs.spad_read = ndev->reg_base + SNB_SPAD_OFFSET +
+					  ndev->limits.max_spads * 4;
+		ndev->reg_ofs.bar2_xlat = ndev->reg_base + SNB_PBAR2XLAT_OFFSET;
+		ndev->reg_ofs.bar4_xlat = ndev->reg_base + SNB_PBAR4XLAT_OFFSET;
+
+		if (ndev->split_bar) {
+			ndev->reg_ofs.bar5_xlat =
+				ndev->reg_base + SNB_PBAR5XLAT_OFFSET;
+			ndev->limits.max_mw = HSX_SPLITBAR_MAX_MW;
+		} else
+			ndev->limits.max_mw = SNB_MAX_MW;
+		break;
+	default:
+		/*
+		 * we should never hit this. the detect function should've
+		 * take cared of everything.
+		 */
+		return -EINVAL;
+	}
+
+	ndev->reg_ofs.lnk_cntl = ndev->reg_base + SNB_NTBCNTL_OFFSET;
+	ndev->reg_ofs.lnk_stat = ndev->reg_base + SNB_SLINK_STATUS_OFFSET;
+	ndev->reg_ofs.spci_cmd = ndev->reg_base + SNB_PCICMD_OFFSET;
+
+	ndev->limits.msix_cnt = SNB_MSIX_CNT;
+	ndev->bits_per_vector = SNB_DB_BITS_PER_VEC;
+
+	return 0;
+}
+
+static int ntb_bwd_setup(struct ntb_device *ndev)
+{
+	int rc;
+	u32 val;
+
+	ndev->hw_type = BWD_HW;
+
+	rc = pci_read_config_dword(ndev->pdev, NTB_PPD_OFFSET, &val);
+	if (rc)
+		return rc;
+
+	switch ((val & BWD_PPD_CONN_TYPE) >> 8) {
+	case NTB_CONN_B2B:
+		ndev->conn_type = NTB_CONN_B2B;
+		break;
+	case NTB_CONN_RP:
+	default:
+		dev_err(&ndev->pdev->dev, "Unsupported NTB configuration\n");
+		return -EINVAL;
+	}
+
+	if (val & BWD_PPD_DEV_TYPE)
+		ndev->dev_type = NTB_DEV_DSD;
+	else
+		ndev->dev_type = NTB_DEV_USD;
+
+	/* Initiate PCI-E link training */
+	rc = pci_write_config_dword(ndev->pdev, NTB_PPD_OFFSET,
+				    val | BWD_PPD_INIT_LINK);
+	if (rc)
+		return rc;
+
+	ndev->reg_ofs.ldb = ndev->reg_base + BWD_PDOORBELL_OFFSET;
+	ndev->reg_ofs.ldb_mask = ndev->reg_base + BWD_PDBMSK_OFFSET;
+	ndev->reg_ofs.rdb = ndev->reg_base + BWD_B2B_DOORBELL_OFFSET;
+	ndev->reg_ofs.bar2_xlat = ndev->reg_base + BWD_SBAR2XLAT_OFFSET;
+	ndev->reg_ofs.bar4_xlat = ndev->reg_base + BWD_SBAR4XLAT_OFFSET;
+	ndev->reg_ofs.lnk_cntl = ndev->reg_base + BWD_NTBCNTL_OFFSET;
+	ndev->reg_ofs.lnk_stat = ndev->reg_base + BWD_LINK_STATUS_OFFSET;
+	ndev->reg_ofs.spad_read = ndev->reg_base + BWD_SPAD_OFFSET;
+	ndev->reg_ofs.spad_write = ndev->reg_base + BWD_B2B_SPAD_OFFSET;
+	ndev->reg_ofs.spci_cmd = ndev->reg_base + BWD_PCICMD_OFFSET;
+	ndev->limits.max_mw = BWD_MAX_MW;
+	ndev->limits.max_spads = BWD_MAX_SPADS;
+	ndev->limits.max_db_bits = BWD_MAX_DB_BITS;
+	ndev->limits.msix_cnt = BWD_MSIX_CNT;
+	ndev->bits_per_vector = BWD_DB_BITS_PER_VEC;
+
+	/* Since bwd doesn't have a link interrupt, setup a poll timer */
+	INIT_DELAYED_WORK(&ndev->hb_timer, bwd_link_poll);
+	INIT_DELAYED_WORK(&ndev->lr_timer, bwd_link_recovery);
+	schedule_delayed_work(&ndev->hb_timer, NTB_HB_TIMEOUT);
+
+	return 0;
+}
+
+static int ntb_device_setup(struct ntb_device *ndev)
+{
+	int rc;
+
+	if (is_ntb_xeon(ndev))
+		rc = ntb_xeon_setup(ndev);
+	else if (is_ntb_atom(ndev))
+		rc = ntb_bwd_setup(ndev);
+	else
+		rc = -ENODEV;
+
+	if (rc)
+		return rc;
+
+	if (ndev->conn_type == NTB_CONN_B2B)
+		/* Enable Bus Master and Memory Space on the secondary side */
+		writew(PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER,
+		       ndev->reg_ofs.spci_cmd);
+
+	return 0;
+}
+
+static void ntb_device_free(struct ntb_device *ndev)
+{
+	if (is_ntb_atom(ndev)) {
+		cancel_delayed_work_sync(&ndev->hb_timer);
+		cancel_delayed_work_sync(&ndev->lr_timer);
+	}
+}
+
+static irqreturn_t bwd_callback_msix_irq(int irq, void *data)
+{
+	struct ntb_db_cb *db_cb = data;
+	struct ntb_device *ndev = db_cb->ndev;
+	unsigned long mask;
+
+	dev_dbg(&ndev->pdev->dev, "MSI-X irq %d received for DB %d\n", irq,
+		db_cb->db_num);
+
+	mask = readw(ndev->reg_ofs.ldb_mask);
+	set_bit(db_cb->db_num * ndev->bits_per_vector, &mask);
+	writew(mask, ndev->reg_ofs.ldb_mask);
+
+	tasklet_schedule(&db_cb->irq_work);
+
+	/* No need to check for the specific HB irq, any interrupt means
+	 * we're connected.
+	 */
+	ndev->last_ts = jiffies;
+
+	writeq((u64) 1 << db_cb->db_num, ndev->reg_ofs.ldb);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t xeon_callback_msix_irq(int irq, void *data)
+{
+	struct ntb_db_cb *db_cb = data;
+	struct ntb_device *ndev = db_cb->ndev;
+	unsigned long mask;
+
+	dev_dbg(&ndev->pdev->dev, "MSI-X irq %d received for DB %d\n", irq,
+		db_cb->db_num);
+
+	mask = readw(ndev->reg_ofs.ldb_mask);
+	set_bit(db_cb->db_num * ndev->bits_per_vector, &mask);
+	writew(mask, ndev->reg_ofs.ldb_mask);
+
+	tasklet_schedule(&db_cb->irq_work);
+
+	/* On Sandybridge, there are 16 bits in the interrupt register
+	 * but only 4 vectors.  So, 5 bits are assigned to the first 3
+	 * vectors, with the 4th having a single bit for link
+	 * interrupts.
+	 */
+	writew(((1 << ndev->bits_per_vector) - 1) <<
+	       (db_cb->db_num * ndev->bits_per_vector), ndev->reg_ofs.ldb);
+
+	return IRQ_HANDLED;
+}
+
+/* Since we do not have a HW doorbell in BWD, this is only used in JF/JT */
+static irqreturn_t xeon_event_msix_irq(int irq, void *dev)
+{
+	struct ntb_device *ndev = dev;
+	int rc;
+
+	dev_dbg(&ndev->pdev->dev, "MSI-X irq %d received for Events\n", irq);
+
+	rc = ntb_link_status(ndev);
+	if (rc)
+		dev_err(&ndev->pdev->dev, "Error determining link status\n");
+
+	/* bit 15 is always the link bit */
+	writew(1 << SNB_LINK_DB, ndev->reg_ofs.ldb);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t ntb_interrupt(int irq, void *dev)
+{
+	struct ntb_device *ndev = dev;
+	unsigned int i = 0;
+
+	if (is_ntb_atom(ndev)) {
+		u64 ldb = readq(ndev->reg_ofs.ldb);
+
+		dev_dbg(&ndev->pdev->dev, "irq %d - ldb = %Lx\n", irq, ldb);
+
+		while (ldb) {
+			i = __ffs(ldb);
+			ldb &= ldb - 1;
+			bwd_callback_msix_irq(irq, &ndev->db_cb[i]);
+		}
+	} else {
+		u16 ldb = readw(ndev->reg_ofs.ldb);
+
+		dev_dbg(&ndev->pdev->dev, "irq %d - ldb = %x\n", irq, ldb);
+
+		if (ldb & SNB_DB_HW_LINK) {
+			xeon_event_msix_irq(irq, dev);
+			ldb &= ~SNB_DB_HW_LINK;
+		}
+
+		while (ldb) {
+			i = __ffs(ldb);
+			ldb &= ldb - 1;
+			xeon_callback_msix_irq(irq, &ndev->db_cb[i]);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int ntb_setup_snb_msix(struct ntb_device *ndev, int msix_entries)
+{
+	struct pci_dev *pdev = ndev->pdev;
+	struct msix_entry *msix;
+	int rc, i;
+
+	if (msix_entries < ndev->limits.msix_cnt)
+		return -ENOSPC;
+
+	rc = pci_enable_msix_exact(pdev, ndev->msix_entries, msix_entries);
+	if (rc < 0)
+		return rc;
+
+	for (i = 0; i < msix_entries; i++) {
+		msix = &ndev->msix_entries[i];
+		WARN_ON(!msix->vector);
+
+		if (i == msix_entries - 1) {
+			rc = request_irq(msix->vector,
+					 xeon_event_msix_irq, 0,
+					 "ntb-event-msix", ndev);
+			if (rc)
+				goto err;
+		} else {
+			rc = request_irq(msix->vector,
+					 xeon_callback_msix_irq, 0,
+					 "ntb-callback-msix",
+					 &ndev->db_cb[i]);
+			if (rc)
+				goto err;
+		}
+	}
+
+	ndev->num_msix = msix_entries;
+	ndev->max_cbs = msix_entries - 1;
+
+	return 0;
+
+err:
+	while (--i >= 0) {
+		/* Code never reaches here for entry nr 'ndev->num_msix - 1' */
+		msix = &ndev->msix_entries[i];
+		free_irq(msix->vector, &ndev->db_cb[i]);
+	}
+
+	pci_disable_msix(pdev);
+	ndev->num_msix = 0;
+
+	return rc;
+}
+
+static int ntb_setup_bwd_msix(struct ntb_device *ndev, int msix_entries)
+{
+	struct pci_dev *pdev = ndev->pdev;
+	struct msix_entry *msix;
+	int rc, i;
+
+	msix_entries = pci_enable_msix_range(pdev, ndev->msix_entries,
+					     1, msix_entries);
+	if (msix_entries < 0)
+		return msix_entries;
+
+	for (i = 0; i < msix_entries; i++) {
+		msix = &ndev->msix_entries[i];
+		WARN_ON(!msix->vector);
+
+		rc = request_irq(msix->vector, bwd_callback_msix_irq, 0,
+				 "ntb-callback-msix", &ndev->db_cb[i]);
+		if (rc)
+			goto err;
+	}
+
+	ndev->num_msix = msix_entries;
+	ndev->max_cbs = msix_entries;
+
+	return 0;
+
+err:
+	while (--i >= 0)
+		free_irq(msix->vector, &ndev->db_cb[i]);
+
+	pci_disable_msix(pdev);
+	ndev->num_msix = 0;
+
+	return rc;
+}
+
+static int ntb_setup_msix(struct ntb_device *ndev)
+{
+	struct pci_dev *pdev = ndev->pdev;
+	int msix_entries;
+	int rc, i;
+
+	msix_entries = pci_msix_vec_count(pdev);
+	if (msix_entries < 0) {
+		rc = msix_entries;
+		goto err;
+	} else if (msix_entries > ndev->limits.msix_cnt) {
+		rc = -EINVAL;
+		goto err;
+	}
+
+	ndev->msix_entries = kmalloc(sizeof(struct msix_entry) * msix_entries,
+				     GFP_KERNEL);
+	if (!ndev->msix_entries) {
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	for (i = 0; i < msix_entries; i++)
+		ndev->msix_entries[i].entry = i;
+
+	if (is_ntb_atom(ndev))
+		rc = ntb_setup_bwd_msix(ndev, msix_entries);
+	else
+		rc = ntb_setup_snb_msix(ndev, msix_entries);
+	if (rc)
+		goto err1;
+
+	return 0;
+
+err1:
+	kfree(ndev->msix_entries);
+err:
+	dev_err(&pdev->dev, "Error allocating MSI-X interrupt\n");
+	return rc;
+}
+
+static int ntb_setup_msi(struct ntb_device *ndev)
+{
+	struct pci_dev *pdev = ndev->pdev;
+	int rc;
+
+	rc = pci_enable_msi(pdev);
+	if (rc)
+		return rc;
+
+	rc = request_irq(pdev->irq, ntb_interrupt, 0, "ntb-msi", ndev);
+	if (rc) {
+		pci_disable_msi(pdev);
+		dev_err(&pdev->dev, "Error allocating MSI interrupt\n");
+		return rc;
+	}
+
+	return 0;
+}
+
+static int ntb_setup_intx(struct ntb_device *ndev)
+{
+	struct pci_dev *pdev = ndev->pdev;
+	int rc;
+
+	pci_msi_off(pdev);
+
+	/* Verify intx is enabled */
+	pci_intx(pdev, 1);
+
+	rc = request_irq(pdev->irq, ntb_interrupt, IRQF_SHARED, "ntb-intx",
+			 ndev);
+	if (rc)
+		return rc;
+
+	return 0;
+}
+
+static int ntb_setup_interrupts(struct ntb_device *ndev)
+{
+	int rc;
+
+	/* On BWD, disable all interrupts.  On SNB, disable all but Link
+	 * Interrupt.  The rest will be unmasked as callbacks are registered.
+	 */
+	if (is_ntb_atom(ndev))
+		writeq(~0, ndev->reg_ofs.ldb_mask);
+	else {
+		u16 var = 1 << SNB_LINK_DB;
+		writew(~var, ndev->reg_ofs.ldb_mask);
+	}
+
+	rc = ntb_setup_msix(ndev);
+	if (!rc)
+		goto done;
+
+	ndev->bits_per_vector = 1;
+	ndev->max_cbs = ndev->limits.max_db_bits;
+
+	rc = ntb_setup_msi(ndev);
+	if (!rc)
+		goto done;
+
+	rc = ntb_setup_intx(ndev);
+	if (rc) {
+		dev_err(&ndev->pdev->dev, "no usable interrupts\n");
+		return rc;
+	}
+
+done:
+	return 0;
+}
+
+static void ntb_free_interrupts(struct ntb_device *ndev)
+{
+	struct pci_dev *pdev = ndev->pdev;
+
+	/* mask interrupts */
+	if (is_ntb_atom(ndev))
+		writeq(~0, ndev->reg_ofs.ldb_mask);
+	else
+		writew(~0, ndev->reg_ofs.ldb_mask);
+
+	if (ndev->num_msix) {
+		struct msix_entry *msix;
+		u32 i;
+
+		for (i = 0; i < ndev->num_msix; i++) {
+			msix = &ndev->msix_entries[i];
+			if (is_ntb_xeon(ndev) && i == ndev->num_msix - 1)
+				free_irq(msix->vector, ndev);
+			else
+				free_irq(msix->vector, &ndev->db_cb[i]);
+		}
+		pci_disable_msix(pdev);
+		kfree(ndev->msix_entries);
+	} else {
+		free_irq(pdev->irq, ndev);
+
+		if (pci_dev_msi_enabled(pdev))
+			pci_disable_msi(pdev);
+	}
+}
+
+static int ntb_create_callbacks(struct ntb_device *ndev)
+{
+	int i;
+
+	/* Chicken-egg issue.  We won't know how many callbacks are necessary
+	 * until we see how many MSI-X vectors we get, but these pointers need
+	 * to be passed into the MSI-X register function.  So, we allocate the
+	 * max, knowing that they might not all be used, to work around this.
+	 */
+	ndev->db_cb = kcalloc(ndev->limits.max_db_bits,
+			      sizeof(struct ntb_db_cb),
+			      GFP_KERNEL);
+	if (!ndev->db_cb)
+		return -ENOMEM;
+
+	for (i = 0; i < ndev->limits.max_db_bits; i++) {
+		ndev->db_cb[i].db_num = i;
+		ndev->db_cb[i].ndev = ndev;
+	}
+
+	return 0;
+}
+
+static void ntb_free_callbacks(struct ntb_device *ndev)
+{
+	int i;
+
+	for (i = 0; i < ndev->limits.max_db_bits; i++)
+		ntb_unregister_db_callback(ndev, i);
+
+	kfree(ndev->db_cb);
+}
+
+static ssize_t ntb_debugfs_read(struct file *filp, char __user *ubuf,
+				size_t count, loff_t *offp)
+{
+	struct ntb_device *ndev;
+	char *buf;
+	ssize_t ret, offset, out_count;
+
+	out_count = 500;
+
+	buf = kmalloc(out_count, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	ndev = filp->private_data;
+	offset = 0;
+	offset += snprintf(buf + offset, out_count - offset,
+			   "NTB Device Information:\n");
+	offset += snprintf(buf + offset, out_count - offset,
+			   "Connection Type - \t\t%s\n",
+			   ndev->conn_type == NTB_CONN_TRANSPARENT ?
+			   "Transparent" : (ndev->conn_type == NTB_CONN_B2B) ?
+			   "Back to back" : "Root Port");
+	offset += snprintf(buf + offset, out_count - offset,
+			   "Device Type - \t\t\t%s\n",
+			   ndev->dev_type == NTB_DEV_USD ?
+			   "DSD/USP" : "USD/DSP");
+	offset += snprintf(buf + offset, out_count - offset,
+			   "Max Number of Callbacks - \t%u\n",
+			   ntb_max_cbs(ndev));
+	offset += snprintf(buf + offset, out_count - offset,
+			   "Link Status - \t\t\t%s\n",
+			   ntb_hw_link_status(ndev) ? "Up" : "Down");
+	if (ntb_hw_link_status(ndev)) {
+		offset += snprintf(buf + offset, out_count - offset,
+				   "Link Speed - \t\t\tPCI-E Gen %u\n",
+				   ndev->link_speed);
+		offset += snprintf(buf + offset, out_count - offset,
+				   "Link Width - \t\t\tx%u\n",
+				   ndev->link_width);
+	}
+
+	if (is_ntb_xeon(ndev)) {
+		u32 status32;
+		u16 status16;
+		int rc;
+
+		offset += snprintf(buf + offset, out_count - offset,
+				   "\nNTB Device Statistics:\n");
+		offset += snprintf(buf + offset, out_count - offset,
+				   "Upstream Memory Miss - \t%u\n",
+				   readw(ndev->reg_base +
+					 SNB_USMEMMISS_OFFSET));
+
+		offset += snprintf(buf + offset, out_count - offset,
+				   "\nNTB Hardware Errors:\n");
+
+		rc = pci_read_config_word(ndev->pdev, SNB_DEVSTS_OFFSET,
+					  &status16);
+		if (!rc)
+			offset += snprintf(buf + offset, out_count - offset,
+					   "DEVSTS - \t%#06x\n", status16);
+
+		rc = pci_read_config_word(ndev->pdev, SNB_LINK_STATUS_OFFSET,
+					  &status16);
+		if (!rc)
+			offset += snprintf(buf + offset, out_count - offset,
+					   "LNKSTS - \t%#06x\n", status16);
+
+		rc = pci_read_config_dword(ndev->pdev, SNB_UNCERRSTS_OFFSET,
+					   &status32);
+		if (!rc)
+			offset += snprintf(buf + offset, out_count - offset,
+					   "UNCERRSTS - \t%#010x\n", status32);
+
+		rc = pci_read_config_dword(ndev->pdev, SNB_CORERRSTS_OFFSET,
+					   &status32);
+		if (!rc)
+			offset += snprintf(buf + offset, out_count - offset,
+					   "CORERRSTS - \t%#010x\n", status32);
+	}
+
+	if (offset > out_count)
+		offset = out_count;
+
+	ret = simple_read_from_buffer(ubuf, count, offp, buf, offset);
+	kfree(buf);
+	return ret;
+}
+
+static const struct file_operations ntb_debugfs_info = {
+	.owner = THIS_MODULE,
+	.open = simple_open,
+	.read = ntb_debugfs_read,
+};
+
+static void ntb_setup_debugfs(struct ntb_device *ndev)
+{
+	if (!debugfs_initialized())
+		return;
+
+	if (!debugfs_dir)
+		debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
+
+	ndev->debugfs_dir = debugfs_create_dir(pci_name(ndev->pdev),
+					       debugfs_dir);
+	if (ndev->debugfs_dir)
+		ndev->debugfs_info = debugfs_create_file("info", S_IRUSR,
+							 ndev->debugfs_dir,
+							 ndev,
+							 &ntb_debugfs_info);
+}
+
+static void ntb_free_debugfs(struct ntb_device *ndev)
+{
+	debugfs_remove_recursive(ndev->debugfs_dir);
+
+	if (debugfs_dir && simple_empty(debugfs_dir)) {
+		debugfs_remove_recursive(debugfs_dir);
+		debugfs_dir = NULL;
+	}
+}
+
+static void ntb_hw_link_up(struct ntb_device *ndev)
+{
+	if (ndev->conn_type == NTB_CONN_TRANSPARENT)
+		ntb_link_event(ndev, NTB_LINK_UP);
+	else {
+		u32 ntb_cntl;
+
+		/* Let's bring the NTB link up */
+		ntb_cntl = readl(ndev->reg_ofs.lnk_cntl);
+		ntb_cntl &= ~(NTB_CNTL_LINK_DISABLE | NTB_CNTL_CFG_LOCK);
+		ntb_cntl |= NTB_CNTL_P2S_BAR23_SNOOP | NTB_CNTL_S2P_BAR23_SNOOP;
+		ntb_cntl |= NTB_CNTL_P2S_BAR4_SNOOP | NTB_CNTL_S2P_BAR4_SNOOP;
+		if (ndev->split_bar)
+			ntb_cntl |= NTB_CNTL_P2S_BAR5_SNOOP |
+				    NTB_CNTL_S2P_BAR5_SNOOP;
+
+		writel(ntb_cntl, ndev->reg_ofs.lnk_cntl);
+	}
+}
+
+static void ntb_hw_link_down(struct ntb_device *ndev)
+{
+	u32 ntb_cntl;
+
+	if (ndev->conn_type == NTB_CONN_TRANSPARENT) {
+		ntb_link_event(ndev, NTB_LINK_DOWN);
+		return;
+	}
+
+	/* Bring NTB link down */
+	ntb_cntl = readl(ndev->reg_ofs.lnk_cntl);
+	ntb_cntl &= ~(NTB_CNTL_P2S_BAR23_SNOOP | NTB_CNTL_S2P_BAR23_SNOOP);
+	ntb_cntl &= ~(NTB_CNTL_P2S_BAR4_SNOOP | NTB_CNTL_S2P_BAR4_SNOOP);
+	if (ndev->split_bar)
+		ntb_cntl &= ~(NTB_CNTL_P2S_BAR5_SNOOP |
+			      NTB_CNTL_S2P_BAR5_SNOOP);
+	ntb_cntl |= NTB_CNTL_LINK_DISABLE | NTB_CNTL_CFG_LOCK;
+	writel(ntb_cntl, ndev->reg_ofs.lnk_cntl);
+}
+
+static void ntb_max_mw_detect(struct ntb_device *ndev)
+{
+	if (ndev->split_bar)
+		ndev->limits.max_mw = HSX_SPLITBAR_MAX_MW;
+	else
+		ndev->limits.max_mw = SNB_MAX_MW;
+}
+
+static int ntb_xeon_detect(struct ntb_device *ndev)
+{
+	int rc, bars_mask;
+	u32 bars;
+	u8 ppd;
+
+	ndev->hw_type = SNB_HW;
+
+	rc = pci_read_config_byte(ndev->pdev, NTB_PPD_OFFSET, &ppd);
+	if (rc)
+		return -EIO;
+
+	if (ppd & SNB_PPD_DEV_TYPE)
+		ndev->dev_type = NTB_DEV_USD;
+	else
+		ndev->dev_type = NTB_DEV_DSD;
+
+	ndev->split_bar = (ppd & SNB_PPD_SPLIT_BAR) ? 1 : 0;
+
+	switch (ppd & SNB_PPD_CONN_TYPE) {
+	case NTB_CONN_B2B:
+		dev_info(&ndev->pdev->dev, "Conn Type = B2B\n");
+		ndev->conn_type = NTB_CONN_B2B;
+		break;
+	case NTB_CONN_RP:
+		dev_info(&ndev->pdev->dev, "Conn Type = RP\n");
+		ndev->conn_type = NTB_CONN_RP;
+		break;
+	case NTB_CONN_TRANSPARENT:
+		dev_info(&ndev->pdev->dev, "Conn Type = TRANSPARENT\n");
+		ndev->conn_type = NTB_CONN_TRANSPARENT;
+		/*
+		 * This mode is default to USD/DSP. HW does not report
+		 * properly in transparent mode as it has no knowledge of
+		 * NTB. We will just force correct here.
+		 */
+		ndev->dev_type = NTB_DEV_USD;
+
+		/*
+		 * This is a way for transparent BAR to figure out if we
+		 * are doing split BAR or not. There is no way for the hw
+		 * on the transparent side to know and set the PPD.
+		 */
+		bars_mask = pci_select_bars(ndev->pdev, IORESOURCE_MEM);
+		bars = hweight32(bars_mask);
+		if (bars == (HSX_SPLITBAR_MAX_MW + 1))
+			ndev->split_bar = 1;
+
+		break;
+	default:
+		dev_err(&ndev->pdev->dev, "Unknown PPD %x\n", ppd);
+		return -ENODEV;
+	}
+
+	ntb_max_mw_detect(ndev);
+
+	return 0;
+}
+
+static int ntb_atom_detect(struct ntb_device *ndev)
+{
+	int rc;
+	u32 ppd;
+
+	ndev->hw_type = BWD_HW;
+	ndev->limits.max_mw = BWD_MAX_MW;
+
+	rc = pci_read_config_dword(ndev->pdev, NTB_PPD_OFFSET, &ppd);
+	if (rc)
+		return rc;
+
+	switch ((ppd & BWD_PPD_CONN_TYPE) >> 8) {
+	case NTB_CONN_B2B:
+		dev_info(&ndev->pdev->dev, "Conn Type = B2B\n");
+		ndev->conn_type = NTB_CONN_B2B;
+		break;
+	case NTB_CONN_RP:
+	default:
+		dev_err(&ndev->pdev->dev, "Unsupported NTB configuration\n");
+		return -EINVAL;
+	}
+
+	if (ppd & BWD_PPD_DEV_TYPE)
+		ndev->dev_type = NTB_DEV_DSD;
+	else
+		ndev->dev_type = NTB_DEV_USD;
+
+	return 0;
+}
+
+static int ntb_device_detect(struct ntb_device *ndev)
+{
+	int rc;
+
+	if (is_ntb_xeon(ndev))
+		rc = ntb_xeon_detect(ndev);
+	else if (is_ntb_atom(ndev))
+		rc = ntb_atom_detect(ndev);
+	else
+		rc = -ENODEV;
+
+	dev_info(&ndev->pdev->dev, "Device Type = %s\n",
+		 ndev->dev_type == NTB_DEV_USD ? "USD/DSP" : "DSD/USP");
+
+	return 0;
+}
+
+static int ntb_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	struct ntb_device *ndev;
+	int rc, i;
+
+	ndev = kzalloc(sizeof(struct ntb_device), GFP_KERNEL);
+	if (!ndev)
+		return -ENOMEM;
+
+	ndev->pdev = pdev;
+
+	ntb_set_errata_flags(ndev);
+
+	ndev->link_status = NTB_LINK_DOWN;
+	pci_set_drvdata(pdev, ndev);
+	ntb_setup_debugfs(ndev);
+
+	rc = pci_enable_device(pdev);
+	if (rc)
+		goto err;
+
+	pci_set_master(ndev->pdev);
+
+	rc = ntb_device_detect(ndev);
+	if (rc)
+		goto err;
+
+	ndev->mw = kcalloc(ndev->limits.max_mw, sizeof(struct ntb_mw),
+			   GFP_KERNEL);
+	if (!ndev->mw) {
+		rc = -ENOMEM;
+		goto err1;
+	}
+
+	if (ndev->split_bar)
+		rc = pci_request_selected_regions(pdev, NTB_SPLITBAR_MASK,
+						  KBUILD_MODNAME);
+	else
+		rc = pci_request_selected_regions(pdev, NTB_BAR_MASK,
+						  KBUILD_MODNAME);
+
+	if (rc)
+		goto err2;
+
+	ndev->reg_base = pci_ioremap_bar(pdev, NTB_BAR_MMIO);
+	if (!ndev->reg_base) {
+		dev_warn(&pdev->dev, "Cannot remap BAR 0\n");
+		rc = -EIO;
+		goto err3;
+	}
+
+	for (i = 0; i < ndev->limits.max_mw; i++) {
+		ndev->mw[i].bar_sz = pci_resource_len(pdev, MW_TO_BAR(i));
+
+		/*
+		 * with the errata we need to steal last of the memory
+		 * windows for workarounds and they point to MMIO registers.
+		 */
+		if ((ndev->wa_flags & WA_SNB_ERR) &&
+		    (i == (ndev->limits.max_mw - 1))) {
+			ndev->mw[i].vbase =
+				ioremap_nocache(pci_resource_start(pdev,
+							MW_TO_BAR(i)),
+						ndev->mw[i].bar_sz);
+		} else {
+			ndev->mw[i].vbase =
+				ioremap_wc(pci_resource_start(pdev,
+							MW_TO_BAR(i)),
+					   ndev->mw[i].bar_sz);
+		}
+
+		dev_info(&pdev->dev, "MW %d size %llu\n", i,
+			 (unsigned long long) ndev->mw[i].bar_sz);
+		if (!ndev->mw[i].vbase) {
+			dev_warn(&pdev->dev, "Cannot remap BAR %d\n",
+				 MW_TO_BAR(i));
+			rc = -EIO;
+			goto err4;
+		}
+	}
+
+	rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(64));
+	if (rc) {
+		rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
+		if (rc)
+			goto err4;
+
+		dev_warn(&pdev->dev, "Cannot DMA highmem\n");
+	}
+
+	rc = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64));
+	if (rc) {
+		rc = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
+		if (rc)
+			goto err4;
+
+		dev_warn(&pdev->dev, "Cannot DMA consistent highmem\n");
+	}
+
+	rc = ntb_device_setup(ndev);
+	if (rc)
+		goto err4;
+
+	rc = ntb_create_callbacks(ndev);
+	if (rc)
+		goto err5;
+
+	rc = ntb_setup_interrupts(ndev);
+	if (rc)
+		goto err6;
+
+	/* The scratchpad registers keep the values between rmmod/insmod,
+	 * blast them now
+	 */
+	for (i = 0; i < ndev->limits.max_spads; i++) {
+		ntb_write_local_spad(ndev, i, 0);
+		ntb_write_remote_spad(ndev, i, 0);
+	}
+
+	rc = ntb_transport_init(pdev);
+	if (rc)
+		goto err7;
+
+	ntb_hw_link_up(ndev);
+
+	return 0;
+
+err7:
+	ntb_free_interrupts(ndev);
+err6:
+	ntb_free_callbacks(ndev);
+err5:
+	ntb_device_free(ndev);
+err4:
+	for (i--; i >= 0; i--)
+		iounmap(ndev->mw[i].vbase);
+	iounmap(ndev->reg_base);
+err3:
+	if (ndev->split_bar)
+		pci_release_selected_regions(pdev, NTB_SPLITBAR_MASK);
+	else
+		pci_release_selected_regions(pdev, NTB_BAR_MASK);
+err2:
+	kfree(ndev->mw);
+err1:
+	pci_disable_device(pdev);
+err:
+	ntb_free_debugfs(ndev);
+	kfree(ndev);
+
+	dev_err(&pdev->dev, "Error loading %s module\n", KBUILD_MODNAME);
+	return rc;
+}
+
+static void ntb_pci_remove(struct pci_dev *pdev)
+{
+	struct ntb_device *ndev = pci_get_drvdata(pdev);
+	int i;
+
+	ntb_hw_link_down(ndev);
+
+	ntb_transport_free(ndev->ntb_transport);
+
+	ntb_free_interrupts(ndev);
+	ntb_free_callbacks(ndev);
+	ntb_device_free(ndev);
+
+	/* need to reset max_mw limits so we can unmap properly */
+	if (ndev->hw_type == SNB_HW)
+		ntb_max_mw_detect(ndev);
+
+	for (i = 0; i < ndev->limits.max_mw; i++)
+		iounmap(ndev->mw[i].vbase);
+
+	kfree(ndev->mw);
+	iounmap(ndev->reg_base);
+	if (ndev->split_bar)
+		pci_release_selected_regions(pdev, NTB_SPLITBAR_MASK);
+	else
+		pci_release_selected_regions(pdev, NTB_BAR_MASK);
+	pci_disable_device(pdev);
+	ntb_free_debugfs(ndev);
+	kfree(ndev);
+}
+
+static struct pci_driver ntb_pci_driver = {
+	.name = KBUILD_MODNAME,
+	.id_table = ntb_pci_tbl,
+	.probe = ntb_pci_probe,
+	.remove = ntb_pci_remove,
+};
+
+module_pci_driver(ntb_pci_driver);
diff --git a/drivers/ntb/ntb_hw.h b/drivers/ntb/ntb_hw.h
new file mode 100644
index 000000000..96de5fc95
--- /dev/null
+++ b/drivers/ntb/ntb_hw.h
@@ -0,0 +1,256 @@
+/*
+ * 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/ntb.h>
+
+#define PCI_DEVICE_ID_INTEL_NTB_B2B_JSF		0x3725
+#define PCI_DEVICE_ID_INTEL_NTB_PS_JSF		0x3726
+#define PCI_DEVICE_ID_INTEL_NTB_SS_JSF		0x3727
+#define PCI_DEVICE_ID_INTEL_NTB_B2B_SNB		0x3C0D
+#define PCI_DEVICE_ID_INTEL_NTB_PS_SNB		0x3C0E
+#define PCI_DEVICE_ID_INTEL_NTB_SS_SNB		0x3C0F
+#define PCI_DEVICE_ID_INTEL_NTB_B2B_IVT		0x0E0D
+#define PCI_DEVICE_ID_INTEL_NTB_PS_IVT		0x0E0E
+#define PCI_DEVICE_ID_INTEL_NTB_SS_IVT		0x0E0F
+#define PCI_DEVICE_ID_INTEL_NTB_B2B_HSX		0x2F0D
+#define PCI_DEVICE_ID_INTEL_NTB_PS_HSX		0x2F0E
+#define PCI_DEVICE_ID_INTEL_NTB_SS_HSX		0x2F0F
+#define PCI_DEVICE_ID_INTEL_NTB_B2B_BWD		0x0C4E
+
+#ifndef readq
+static inline u64 readq(void __iomem *addr)
+{
+	return readl(addr) | (((u64) readl(addr + 4)) << 32LL);
+}
+#endif
+
+#ifndef writeq
+static inline void writeq(u64 val, void __iomem *addr)
+{
+	writel(val & 0xffffffff, addr);
+	writel(val >> 32, addr + 4);
+}
+#endif
+
+#define NTB_BAR_MMIO		0
+#define NTB_BAR_23		2
+#define NTB_BAR_4		4
+#define NTB_BAR_5		5
+
+#define NTB_BAR_MASK		((1 << NTB_BAR_MMIO) | (1 << NTB_BAR_23) |\
+				 (1 << NTB_BAR_4))
+#define NTB_SPLITBAR_MASK	((1 << NTB_BAR_MMIO) | (1 << NTB_BAR_23) |\
+				 (1 << NTB_BAR_4) | (1 << NTB_BAR_5))
+
+#define NTB_HB_TIMEOUT		msecs_to_jiffies(1000)
+
+enum ntb_hw_event {
+	NTB_EVENT_SW_EVENT0 = 0,
+	NTB_EVENT_SW_EVENT1,
+	NTB_EVENT_SW_EVENT2,
+	NTB_EVENT_HW_ERROR,
+	NTB_EVENT_HW_LINK_UP,
+	NTB_EVENT_HW_LINK_DOWN,
+};
+
+struct ntb_mw {
+	dma_addr_t phys_addr;
+	void __iomem *vbase;
+	resource_size_t bar_sz;
+};
+
+struct ntb_db_cb {
+	int (*callback)(void *data, int db_num);
+	unsigned int db_num;
+	void *data;
+	struct ntb_device *ndev;
+	struct tasklet_struct irq_work;
+};
+
+#define WA_SNB_ERR	0x00000001
+
+struct ntb_device {
+	struct pci_dev *pdev;
+	struct msix_entry *msix_entries;
+	void __iomem *reg_base;
+	struct ntb_mw *mw;
+	struct {
+		unsigned char max_mw;
+		unsigned char max_spads;
+		unsigned char max_db_bits;
+		unsigned char msix_cnt;
+	} limits;
+	struct {
+		void __iomem *ldb;
+		void __iomem *ldb_mask;
+		void __iomem *rdb;
+		void __iomem *bar2_xlat;
+		void __iomem *bar4_xlat;
+		void __iomem *bar5_xlat;
+		void __iomem *spad_write;
+		void __iomem *spad_read;
+		void __iomem *lnk_cntl;
+		void __iomem *lnk_stat;
+		void __iomem *spci_cmd;
+	} reg_ofs;
+	struct ntb_transport *ntb_transport;
+	void (*event_cb)(void *handle, enum ntb_hw_event event);
+
+	struct ntb_db_cb *db_cb;
+	unsigned char hw_type;
+	unsigned char conn_type;
+	unsigned char dev_type;
+	unsigned char num_msix;
+	unsigned char bits_per_vector;
+	unsigned char max_cbs;
+	unsigned char link_width;
+	unsigned char link_speed;
+	unsigned char link_status;
+	unsigned char split_bar;
+
+	struct delayed_work hb_timer;
+	unsigned long last_ts;
+
+	struct delayed_work lr_timer;
+
+	struct dentry *debugfs_dir;
+	struct dentry *debugfs_info;
+
+	unsigned int wa_flags;
+};
+
+/**
+ * ntb_max_cbs() - return the max callbacks
+ * @ndev: pointer to ntb_device instance
+ *
+ * Given the ntb pointer, return the maximum number of callbacks
+ *
+ * RETURNS: the maximum number of callbacks
+ */
+static inline unsigned char ntb_max_cbs(struct ntb_device *ndev)
+{
+	return ndev->max_cbs;
+}
+
+/**
+ * ntb_max_mw() - return the max number of memory windows
+ * @ndev: pointer to ntb_device instance
+ *
+ * Given the ntb pointer, return the maximum number of memory windows
+ *
+ * RETURNS: the maximum number of memory windows
+ */
+static inline unsigned char ntb_max_mw(struct ntb_device *ndev)
+{
+	return ndev->limits.max_mw;
+}
+
+/**
+ * ntb_hw_link_status() - return the hardware link status
+ * @ndev: pointer to ntb_device instance
+ *
+ * Returns true if the hardware is connected to the remote system
+ *
+ * RETURNS: true or false based on the hardware link state
+ */
+static inline bool ntb_hw_link_status(struct ntb_device *ndev)
+{
+	return ndev->link_status == NTB_LINK_UP;
+}
+
+/**
+ * ntb_query_pdev() - return the pci_dev pointer
+ * @ndev: pointer to ntb_device instance
+ *
+ * Given the ntb pointer, return the pci_dev pointer for the NTB hardware device
+ *
+ * RETURNS: a pointer to the ntb pci_dev
+ */
+static inline struct pci_dev *ntb_query_pdev(struct ntb_device *ndev)
+{
+	return ndev->pdev;
+}
+
+/**
+ * ntb_query_debugfs() - return the debugfs pointer
+ * @ndev: pointer to ntb_device instance
+ *
+ * Given the ntb pointer, return the debugfs directory pointer for the NTB
+ * hardware device
+ *
+ * RETURNS: a pointer to the debugfs directory
+ */
+static inline struct dentry *ntb_query_debugfs(struct ntb_device *ndev)
+{
+	return ndev->debugfs_dir;
+}
+
+struct ntb_device *ntb_register_transport(struct pci_dev *pdev,
+					  void *transport);
+void ntb_unregister_transport(struct ntb_device *ndev);
+void ntb_set_mw_addr(struct ntb_device *ndev, unsigned int mw, u64 addr);
+int ntb_register_db_callback(struct ntb_device *ndev, unsigned int idx,
+			     void *data, int (*db_cb_func)(void *data,
+							   int db_num));
+void ntb_unregister_db_callback(struct ntb_device *ndev, unsigned int idx);
+int ntb_register_event_callback(struct ntb_device *ndev,
+				void (*event_cb_func)(void *handle,
+						      enum ntb_hw_event event));
+void ntb_unregister_event_callback(struct ntb_device *ndev);
+int ntb_get_max_spads(struct ntb_device *ndev);
+int ntb_write_local_spad(struct ntb_device *ndev, unsigned int idx, u32 val);
+int ntb_read_local_spad(struct ntb_device *ndev, unsigned int idx, u32 *val);
+int ntb_write_remote_spad(struct ntb_device *ndev, unsigned int idx, u32 val);
+int ntb_read_remote_spad(struct ntb_device *ndev, unsigned int idx, u32 *val);
+resource_size_t ntb_get_mw_base(struct ntb_device *ndev, unsigned int mw);
+void __iomem *ntb_get_mw_vbase(struct ntb_device *ndev, unsigned int mw);
+u64 ntb_get_mw_size(struct ntb_device *ndev, unsigned int mw);
+void ntb_ring_doorbell(struct ntb_device *ndev, unsigned int idx);
+void *ntb_find_transport(struct pci_dev *pdev);
+
+int ntb_transport_init(struct pci_dev *pdev);
+void ntb_transport_free(void *transport);
diff --git a/drivers/ntb/ntb_regs.h b/drivers/ntb/ntb_regs.h
new file mode 100644
index 000000000..f028ff81f
--- /dev/null
+++ b/drivers/ntb/ntb_regs.h
@@ -0,0 +1,177 @@
+/*
+ * 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>
+ */
+
+#define NTB_LINK_STATUS_ACTIVE	0x2000
+#define NTB_LINK_SPEED_MASK	0x000f
+#define NTB_LINK_WIDTH_MASK	0x03f0
+
+#define SNB_MSIX_CNT		4
+#define SNB_MAX_B2B_SPADS	16
+#define SNB_MAX_COMPAT_SPADS	16
+/* Reserve the uppermost bit for link interrupt */
+#define SNB_MAX_DB_BITS		15
+#define SNB_LINK_DB		15
+#define SNB_DB_BITS_PER_VEC	5
+#define HSX_SPLITBAR_MAX_MW	3
+#define SNB_MAX_MW		2
+#define SNB_ERRATA_MAX_MW	1
+
+#define SNB_DB_HW_LINK		0x8000
+
+#define SNB_UNCERRSTS_OFFSET	0x014C
+#define SNB_CORERRSTS_OFFSET	0x0158
+#define SNB_LINK_STATUS_OFFSET	0x01A2
+#define SNB_PCICMD_OFFSET	0x0504
+#define SNB_DEVCTRL_OFFSET	0x0598
+#define SNB_DEVSTS_OFFSET	0x059A
+#define SNB_SLINK_STATUS_OFFSET	0x05A2
+
+#define SNB_PBAR2LMT_OFFSET	0x0000
+#define SNB_PBAR4LMT_OFFSET	0x0008
+#define SNB_PBAR5LMT_OFFSET	0x000C
+#define SNB_PBAR2XLAT_OFFSET	0x0010
+#define SNB_PBAR4XLAT_OFFSET	0x0018
+#define SNB_PBAR5XLAT_OFFSET	0x001C
+#define SNB_SBAR2LMT_OFFSET	0x0020
+#define SNB_SBAR4LMT_OFFSET	0x0028
+#define SNB_SBAR5LMT_OFFSET	0x002C
+#define SNB_SBAR2XLAT_OFFSET	0x0030
+#define SNB_SBAR4XLAT_OFFSET	0x0038
+#define SNB_SBAR5XLAT_OFFSET	0x003C
+#define SNB_SBAR0BASE_OFFSET	0x0040
+#define SNB_SBAR2BASE_OFFSET	0x0048
+#define SNB_SBAR4BASE_OFFSET	0x0050
+#define SNB_SBAR5BASE_OFFSET	0x0054
+#define SNB_NTBCNTL_OFFSET	0x0058
+#define SNB_SBDF_OFFSET		0x005C
+#define SNB_PDOORBELL_OFFSET	0x0060
+#define SNB_PDBMSK_OFFSET	0x0062
+#define SNB_SDOORBELL_OFFSET	0x0064
+#define SNB_SDBMSK_OFFSET	0x0066
+#define SNB_USMEMMISS_OFFSET	0x0070
+#define SNB_SPAD_OFFSET		0x0080
+#define SNB_SPADSEMA4_OFFSET	0x00c0
+#define SNB_WCCNTRL_OFFSET	0x00e0
+#define SNB_B2B_SPAD_OFFSET	0x0100
+#define SNB_B2B_DOORBELL_OFFSET	0x0140
+#define SNB_B2B_XLAT_OFFSETL	0x0144
+#define SNB_B2B_XLAT_OFFSETU	0x0148
+
+/*
+ * The addresses are setup so the 32bit BARs can function. Thus
+ * the addresses are all in 32bit space
+ */
+#define SNB_MBAR01_USD_ADDR	0x000000002100000CULL
+#define SNB_MBAR23_USD_ADDR	0x000000004100000CULL
+#define SNB_MBAR4_USD_ADDR	0x000000008100000CULL
+#define SNB_MBAR5_USD_ADDR	0x00000000A100000CULL
+#define SNB_MBAR01_DSD_ADDR	0x000000002000000CULL
+#define SNB_MBAR23_DSD_ADDR	0x000000004000000CULL
+#define SNB_MBAR4_DSD_ADDR	0x000000008000000CULL
+#define SNB_MBAR5_DSD_ADDR	0x00000000A000000CULL
+
+#define BWD_MSIX_CNT		34
+#define BWD_MAX_SPADS		16
+#define BWD_MAX_DB_BITS		34
+#define BWD_DB_BITS_PER_VEC	1
+#define BWD_MAX_MW		2
+
+#define BWD_PCICMD_OFFSET	0xb004
+#define BWD_MBAR23_OFFSET	0xb018
+#define BWD_MBAR45_OFFSET	0xb020
+#define BWD_DEVCTRL_OFFSET	0xb048
+#define BWD_LINK_STATUS_OFFSET	0xb052
+#define BWD_ERRCORSTS_OFFSET	0xb110
+
+#define BWD_SBAR2XLAT_OFFSET	0x0008
+#define BWD_SBAR4XLAT_OFFSET	0x0010
+#define BWD_PDOORBELL_OFFSET	0x0020
+#define BWD_PDBMSK_OFFSET	0x0028
+#define BWD_NTBCNTL_OFFSET	0x0060
+#define BWD_EBDF_OFFSET		0x0064
+#define BWD_SPAD_OFFSET		0x0080
+#define BWD_SPADSEMA_OFFSET	0x00c0
+#define BWD_STKYSPAD_OFFSET	0x00c4
+#define BWD_PBAR2XLAT_OFFSET	0x8008
+#define BWD_PBAR4XLAT_OFFSET	0x8010
+#define BWD_B2B_DOORBELL_OFFSET	0x8020
+#define BWD_B2B_SPAD_OFFSET	0x8080
+#define BWD_B2B_SPADSEMA_OFFSET	0x80c0
+#define BWD_B2B_STKYSPAD_OFFSET	0x80c4
+
+#define BWD_MODPHY_PCSREG4	0x1c004
+#define BWD_MODPHY_PCSREG6	0x1c006
+
+#define BWD_IP_BASE		0xC000
+#define BWD_DESKEWSTS_OFFSET	(BWD_IP_BASE + 0x3024)
+#define BWD_LTSSMERRSTS0_OFFSET (BWD_IP_BASE + 0x3180)
+#define BWD_LTSSMSTATEJMP_OFFSET	(BWD_IP_BASE + 0x3040)
+#define BWD_IBSTERRRCRVSTS0_OFFSET	(BWD_IP_BASE + 0x3324)
+
+#define BWD_DESKEWSTS_DBERR	(1 << 15)
+#define BWD_LTSSMERRSTS0_UNEXPECTEDEI	(1 << 20)
+#define BWD_LTSSMSTATEJMP_FORCEDETECT	(1 << 2)
+#define BWD_IBIST_ERR_OFLOW	0x7FFF7FFF
+
+#define NTB_CNTL_CFG_LOCK		(1 << 0)
+#define NTB_CNTL_LINK_DISABLE		(1 << 1)
+#define NTB_CNTL_S2P_BAR23_SNOOP	(1 << 2)
+#define NTB_CNTL_P2S_BAR23_SNOOP	(1 << 4)
+#define NTB_CNTL_S2P_BAR4_SNOOP	(1 << 6)
+#define NTB_CNTL_P2S_BAR4_SNOOP	(1 << 8)
+#define NTB_CNTL_S2P_BAR5_SNOOP	(1 << 12)
+#define NTB_CNTL_P2S_BAR5_SNOOP	(1 << 14)
+#define BWD_CNTL_LINK_DOWN		(1 << 16)
+
+#define NTB_PPD_OFFSET		0x00D4
+#define SNB_PPD_CONN_TYPE	0x0003
+#define SNB_PPD_DEV_TYPE	0x0010
+#define SNB_PPD_SPLIT_BAR	(1 << 6)
+#define BWD_PPD_INIT_LINK	0x0008
+#define BWD_PPD_CONN_TYPE	0x0300
+#define BWD_PPD_DEV_TYPE	0x1000
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);