NTB: Move files in preparation for NTB abstraction

This patch only moves files to their new locations, before applying the
next two patches adding the NTB Abstraction layer.  Splitting this patch
from the next is intended make distinct which code is changed only due
to moving the files, versus which are substantial code changes in adding
the NTB Abstraction layer.

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

2 files changed, 2279 insertions, 0 deletions

diff --git a/drivers/ntb/hw/intel/ntb_hw_intel.c b/drivers/ntb/hw/intel/ntb_hw_intel.c
new file mode 100644
index 000000000000..044534a995f1
--- /dev/null
+++ b/drivers/ntb/hw/intel/ntb_hw_intel.c
@@ -0,0 +1,1894 @@
+/*
+ * 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_intel.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_callb