Merge tag 'ntb-4.5' of git://github.com/jonmason/ntb

Pull NTB updates from Jon Mason:
 "A new driver to support AMD NTB, a NTB performance test driver, NTB
  bugs fixes, and the ability to recover from running out of DMA
  descriptors"

* tag 'ntb-4.5' of git://github.com/jonmason/ntb:
  NTB: Fix macro parameter conflict with field name
  NTB: Add support for AMD PCI-Express Non-Transparent Bridge
  ntb: ntb perf tool
  NTB: Address out of DMA descriptor issue with NTB
  NTB: Clear property bits in BAR value
  NTB: ntb_process_tx error path bug

MAINTAINERS

@@ -7702,6 +7702,12 @@ W:	https://github.com/jonmason/ntb/wiki
 T:	git git://github.com/jonmason/ntb.git
 F:	drivers/ntb/hw/intel/
 
+NTB AMD DRIVER
+M:	Xiangliang Yu <Xiangliang.Yu@amd.com>
+L:	linux-ntb@googlegroups.com
+S:	Supported
+F:	drivers/ntb/hw/amd/
+
 NTFS FILESYSTEM
 M:	Anton Altaparmakov <anton@tuxera.com>
 L:	linux-ntfs-dev@lists.sourceforge.net

drivers/ntb/hw/Kconfig

+source "drivers/ntb/hw/amd/Kconfig"
 source "drivers/ntb/hw/intel/Kconfig"

drivers/ntb/hw/Makefile

+obj-$(CONFIG_NTB_AMD)	+= amd/
 obj-$(CONFIG_NTB_INTEL)	+= intel/

drivers/ntb/hw/amd/Kconfig

+config NTB_AMD
+	tristate "AMD Non-Transparent Bridge support"
+	depends on X86_64
+	help
+	 This driver supports AMD NTB on capable Zeppelin hardware.
+
+	 If unsure, say N.

drivers/ntb/hw/amd/Makefile

+obj-$(CONFIG_NTB_AMD) += ntb_hw_amd.o

drivers/ntb/hw/amd/ntb_hw_amd.c

+/*
+ * 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) 2016 Advanced Micro Devices, Inc. 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) 2016 Advanced Micro Devices, Inc. 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 AMD 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.
+ *
+ * AMD PCIe NTB Linux driver
+ *
+ * Contact Information:
+ * Xiangliang Yu <Xiangliang.Yu@amd.com>
+ */
+
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <linux/pci.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/ntb.h>
+
+#include "ntb_hw_amd.h"
+
+#define NTB_NAME	"ntb_hw_amd"
+#define NTB_DESC	"AMD(R) PCI-E Non-Transparent Bridge Driver"
+#define NTB_VER		"1.0"
+
+MODULE_DESCRIPTION(NTB_DESC);
+MODULE_VERSION(NTB_VER);
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("AMD Inc.");
+
+static const struct file_operations amd_ntb_debugfs_info;
+static struct dentry *debugfs_dir;
+
+static int ndev_mw_to_bar(struct amd_ntb_dev *ndev, int idx)
+{
+	if (idx < 0 || idx > ndev->mw_count)
+		return -EINVAL;
+
+	return 1 << idx;
+}
+
+static int amd_ntb_mw_count(struct ntb_dev *ntb)
+{
+	return ntb_ndev(ntb)->mw_count;
+}
+
+static int amd_ntb_mw_get_range(struct ntb_dev *ntb, int idx,
+				phys_addr_t *base,
+				resource_size_t *size,
+				resource_size_t *align,
+				resource_size_t *align_size)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	int bar;
+
+	bar = ndev_mw_to_bar(ndev, idx);
+	if (bar < 0)
+		return bar;
+
+	if (base)
+		*base = pci_resource_start(ndev->ntb.pdev, bar);
+
+	if (size)
+		*size = pci_resource_len(ndev->ntb.pdev, bar);
+
+	if (align)
+		*align = SZ_4K;
+
+	if (align_size)
+		*align_size = 1;
+
+	return 0;
+}
+
+static int amd_ntb_mw_set_trans(struct ntb_dev *ntb, int idx,
+				dma_addr_t addr, resource_size_t size)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	unsigned long xlat_reg, limit_reg = 0;
+	resource_size_t mw_size;
+	void __iomem *mmio, *peer_mmio;
+	u64 base_addr, limit, reg_val;
+	int bar;
+
+	bar = ndev_mw_to_bar(ndev, idx);
+	if (bar < 0)
+		return bar;
+
+	mw_size = pci_resource_len(ndev->ntb.pdev, bar);
+
+	/* make sure the range fits in the usable mw size */
+	if (size > mw_size)
+		return -EINVAL;
+
+	mmio = ndev->self_mmio;
+	peer_mmio = ndev->peer_mmio;
+
+	base_addr = pci_resource_start(ndev->ntb.pdev, bar);
+
+	if (bar != 1) {
+		xlat_reg = AMD_BAR23XLAT_OFFSET + ((bar - 2) << 3);
+		limit_reg = AMD_BAR23LMT_OFFSET + ((bar - 2) << 3);
+
+		/* Set the limit if supported */
+		limit = base_addr + size;
+
+		/* set and verify setting the translation address */
+		write64(addr, peer_mmio + xlat_reg);
+		reg_val = read64(peer_mmio + xlat_reg);
+		if (reg_val != addr) {
+			write64(0, peer_mmio + xlat_reg);
+			return -EIO;
+		}
+
+		/* set and verify setting the limit */
+		write64(limit, mmio + limit_reg);
+		reg_val = read64(mmio + limit_reg);
+		if (reg_val != limit) {
+			write64(base_addr, mmio + limit_reg);
+			write64(0, peer_mmio + xlat_reg);
+			return -EIO;
+		}
+	} else {
+		xlat_reg = AMD_BAR1XLAT_OFFSET;
+		limit_reg = AMD_BAR1LMT_OFFSET;
+
+		/* split bar addr range must all be 32 bit */
+		if (addr & (~0ull << 32))
+			return -EINVAL;
+		if ((addr + size) & (~0ull << 32))
+			return -EINVAL;
+
+		/* Set the limit if supported */
+		limit = base_addr + size;
+
+		/* set and verify setting the translation address */
+		write64(addr, peer_mmio + xlat_reg);
+		reg_val = read64(peer_mmio + xlat_reg);
+		if (reg_val != addr) {
+			write64(0, peer_mmio + xlat_reg);
+			return -EIO;
+		}
+
+		/* set and verify setting the limit */
+		writel(limit, mmio + limit_reg);
+		reg_val = readl(mmio + limit_reg);
+		if (reg_val != limit) {
+			writel(base_addr, mmio + limit_reg);
+			writel(0, peer_mmio + xlat_reg);
+			return -EIO;
+		}
+	}
+
+	return 0;
+}
+
+static int amd_link_is_up(struct amd_ntb_dev *ndev)
+{
+	if (!ndev->peer_sta)
+		return NTB_LNK_STA_ACTIVE(ndev->cntl_sta);
+
+	/* If peer_sta is reset or D0 event, the ISR has
+	 * started a timer to check link status of hardware.
+	 * So here just clear status bit. And if peer_sta is
+	 * D3 or PME_TO, D0/reset event will be happened when
+	 * system wakeup/poweron, so do nothing here.
+	 */
+	if (ndev->peer_sta & AMD_PEER_RESET_EVENT)
+		ndev->peer_sta &= ~AMD_PEER_RESET_EVENT;
+	else if (ndev->peer_sta & AMD_PEER_D0_EVENT)
+		ndev->peer_sta = 0;
+
+	return 0;
+}
+
+static int amd_ntb_link_is_up(struct ntb_dev *ntb,
+			      enum ntb_speed *speed,
+			      enum ntb_width *width)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	int ret = 0;
+
+	if (amd_link_is_up(ndev)) {
+		if (speed)
+			*speed = NTB_LNK_STA_SPEED(ndev->lnk_sta);
+		if (width)
+			*width = NTB_LNK_STA_WIDTH(ndev->lnk_sta);
+
+		dev_dbg(ndev_dev(ndev), "link is up.\n");
+
+		ret = 1;
+	} else {
+		if (speed)
+			*speed = NTB_SPEED_NONE;
+		if (width)
+			*width = NTB_WIDTH_NONE;
+
+		dev_dbg(ndev_dev(ndev), "link is down.\n");
+	}
+
+	return ret;
+}
+
+static int amd_ntb_link_enable(struct ntb_dev *ntb,
+			       enum ntb_speed max_speed,
+			       enum ntb_width max_width)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	u32 ntb_ctl;
+
+	/* Enable event interrupt */
+	ndev->int_mask &= ~AMD_EVENT_INTMASK;
+	writel(ndev->int_mask, mmio + AMD_INTMASK_OFFSET);
+
+	if (ndev->ntb.topo == NTB_TOPO_SEC)
+		return -EINVAL;
+	dev_dbg(ndev_dev(ndev), "Enabling Link.\n");
+
+	ntb_ctl = readl(mmio + AMD_CNTL_OFFSET);
+	ntb_ctl |= (PMM_REG_CTL | SMM_REG_CTL);
+	writel(ntb_ctl, mmio + AMD_CNTL_OFFSET);
+
+	return 0;
+}
+
+static int amd_ntb_link_disable(struct ntb_dev *ntb)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	u32 ntb_ctl;
+
+	/* Disable event interrupt */
+	ndev->int_mask |= AMD_EVENT_INTMASK;
+	writel(ndev->int_mask, mmio + AMD_INTMASK_OFFSET);
+
+	if (ndev->ntb.topo == NTB_TOPO_SEC)
+		return -EINVAL;
+	dev_dbg(ndev_dev(ndev), "Enabling Link.\n");
+
+	ntb_ctl = readl(mmio + AMD_CNTL_OFFSET);
+	ntb_ctl &= ~(PMM_REG_CTL | SMM_REG_CTL);
+	writel(ntb_ctl, mmio + AMD_CNTL_OFFSET);
+
+	return 0;
+}
+
+static u64 amd_ntb_db_valid_mask(struct ntb_dev *ntb)
+{
+	return ntb_ndev(ntb)->db_valid_mask;
+}
+
+static int amd_ntb_db_vector_count(struct ntb_dev *ntb)
+{
+	return ntb_ndev(ntb)->db_count;
+}
+
+static u64 amd_ntb_db_vector_mask(struct ntb_dev *ntb, int db_vector)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+
+	if (db_vector < 0 || db_vector > ndev->db_count)
+		return 0;
+
+	return ntb_ndev(ntb)->db_valid_mask & (1 << db_vector);
+}
+
+static u64 amd_ntb_db_read(struct ntb_dev *ntb)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+
+	return (u64)readw(mmio + AMD_DBSTAT_OFFSET);
+}
+
+static int amd_ntb_db_clear(struct ntb_dev *ntb, u64 db_bits)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+
+	writew((u16)db_bits, mmio + AMD_DBSTAT_OFFSET);
+
+	return 0;
+}
+
+static int amd_ntb_db_set_mask(struct ntb_dev *ntb, u64 db_bits)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	unsigned long flags;
+
+	if (db_bits & ~ndev->db_valid_mask)
+		return -EINVAL;
+
+	spin_lock_irqsave(&ndev->db_mask_lock, flags);
+	ndev->db_mask |= db_bits;
+	writew((u16)ndev->db_mask, mmio + AMD_DBMASK_OFFSET);
+	spin_unlock_irqrestore(&ndev->db_mask_lock, flags);
+
+	return 0;
+}
+
+static int amd_ntb_db_clear_mask(struct ntb_dev *ntb, u64 db_bits)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	unsigned long flags;
+
+	if (db_bits & ~ndev->db_valid_mask)
+		return -EINVAL;
+
+	spin_lock_irqsave(&ndev->db_mask_lock, flags);
+	ndev->db_mask &= ~db_bits;
+	writew((u16)ndev->db_mask, mmio + AMD_DBMASK_OFFSET);
+	spin_unlock_irqrestore(&ndev->db_mask_lock, flags);
+
+	return 0;
+}
+
+static int amd_ntb_peer_db_addr(struct ntb_dev *ntb,
+				phys_addr_t *db_addr,
+				resource_size_t *db_size)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+
+	if (db_addr)
+		*db_addr = (phys_addr_t)(ndev->peer_mmio + AMD_DBREQ_OFFSET);
+	if (db_size)
+		*db_size = sizeof(u32);
+
+	return 0;
+}
+
+static int amd_ntb_peer_db_set(struct ntb_dev *ntb, u64 db_bits)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+
+	writew((u16)db_bits, mmio + AMD_DBREQ_OFFSET);
+
+	return 0;
+}
+
+static int amd_ntb_spad_count(struct ntb_dev *ntb)
+{
+	return ntb_ndev(ntb)->spad_count;
+}
+
+static u32 amd_ntb_spad_read(struct ntb_dev *ntb, int idx)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	u32 offset;
+
+	if (idx < 0 || idx >= ndev->spad_count)
+		return 0;
+
+	offset = ndev->self_spad + (idx << 2);
+	return readl(mmio + AMD_SPAD_OFFSET + offset);
+}
+
+static int amd_ntb_spad_write(struct ntb_dev *ntb,
+			      int idx, u32 val)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	u32 offset;
+
+	if (idx < 0 || idx >= ndev->spad_count)
+		return -EINVAL;
+
+	offset = ndev->self_spad + (idx << 2);
+	writel(val, mmio + AMD_SPAD_OFFSET + offset);
+
+	return 0;
+}
+
+static int amd_ntb_peer_spad_addr(struct ntb_dev *ntb, int idx,
+				  phys_addr_t *spad_addr)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+
+	if (idx < 0 || idx >= ndev->spad_count)
+		return -EINVAL;
+
+	if (spad_addr)
+		*spad_addr = (phys_addr_t)(ndev->self_mmio + AMD_SPAD_OFFSET +
+					   ndev->peer_spad + (idx << 2));
+	return 0;
+}
+
+static u32 amd_ntb_peer_spad_read(struct ntb_dev *ntb, int idx)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	u32 offset;
+
+	if (idx < 0 || idx >= ndev->spad_count)
+		return -EINVAL;
+
+	offset = ndev->peer_spad + (idx << 2);
+	return readl(mmio + AMD_SPAD_OFFSET + offset);
+}
+
+static int amd_ntb_peer_spad_write(struct ntb_dev *ntb,
+				   int idx, u32 val)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	u32 offset;
+
+	if (idx < 0 || idx >= ndev->spad_count)
+		return -EINVAL;
+
+	offset = ndev->peer_spad + (idx << 2);
+	writel(val, mmio + AMD_SPAD_OFFSET + offset);
+
+	return 0;
+}
+
+static const struct ntb_dev_ops amd_ntb_ops = {
+	.mw_count		= amd_ntb_mw_count,
+	.mw_get_range		= amd_ntb_mw_get_range,
+	.mw_set_trans		= amd_ntb_mw_set_trans,
+	.link_is_up		= amd_ntb_link_is_up,
+	.link_enable		= amd_ntb_link_enable,
+	.link_disable		= amd_ntb_link_disable,
+	.db_valid_mask		= amd_ntb_db_valid_mask,
+	.db_vector_count	= amd_ntb_db_vector_count,
+	.db_vector_mask		= amd_ntb_db_vector_mask,
+	.db_read		= amd_ntb_db_read,
+	.db_clear		= amd_ntb_db_clear,
+	.db_set_mask		= amd_ntb_db_set_mask,
+	.db_clear_mask		= amd_ntb_db_clear_mask,
+	.peer_db_addr		= amd_ntb_peer_db_addr,
+	.peer_db_set		= amd_ntb_peer_db_set,
+	.spad_count		= amd_ntb_spad_count,
+	.spad_read		= amd_ntb_spad_read,
+	.spad_write		= amd_ntb_spad_write,
+	.peer_spad_addr		= amd_ntb_peer_spad_addr,
+	.peer_spad_read		= amd_ntb_peer_spad_read,
+	.peer_spad_write	= amd_ntb_peer_spad_write,
+};
+
+static void amd_ack_smu(struct amd_ntb_dev *ndev, u32 bit)
+{
+	void __iomem *mmio = ndev->self_mmio;
+	int reg;
+
+	reg = readl(mmio + AMD_SMUACK_OFFSET);
+	reg |= bit;
+	writel(reg, mmio + AMD_SMUACK_OFFSET);
+
+	ndev->peer_sta |= bit;
+}
+
+static void amd_handle_event(struct amd_ntb_dev *ndev, int vec)
+{
+	void __iomem *mmio = ndev->self_mmio;
+	u32 status;
+
+	status = readl(mmio + AMD_INTSTAT_OFFSET);
+	if (!(status & AMD_EVENT_INTMASK))
+		return;
+
+	dev_dbg(ndev_dev(ndev), "status = 0x%x and vec = %d\n", status, vec);
+
+	status &= AMD_EVENT_INTMASK;
+	switch (status) {
+	case AMD_PEER_FLUSH_EVENT:
+		dev_info(ndev_dev(ndev), "Flush is done.\n");
+		break;
+	case AMD_PEER_RESET_EVENT:
+		amd_ack_smu(ndev, AMD_PEER_RESET_EVENT);
+
+		/* link down first */
+		ntb_link_event(&ndev->ntb);
+		/* polling peer status */
+		schedule_delayed_work(&ndev->hb_timer, AMD_LINK_HB_TIMEOUT);
+
+		break;
+	case AMD_PEER_D3_EVENT:
+	case AMD_PEER_PMETO_EVENT:
+		amd_ack_smu(ndev, status);
+
+		/* link down */
+		ntb_link_event(&ndev->ntb);
+
+		break;
+	case AMD_PEER_D0_EVENT:
+		mmio = ndev->peer_mmio;
+		status = readl(mmio + AMD_PMESTAT_OFFSET);
+		/* check if this is WAKEUP event */
+		if (status & 0x1)
+			dev_info(ndev_dev(ndev), "Wakeup is done.\n");
+
+		amd_ack_smu(ndev, AMD_PEER_D0_EVENT);
+
+		/* start a timer to poll link status */
+		schedule_delayed_work(&ndev->hb_timer,
+				      AMD_LINK_HB_TIMEOUT);
+		break;
+	default:
+		dev_info(ndev_dev(ndev), "event status = 0x%x.\n", status);
+		break;
+	}
+}
+
+static irqreturn_t ndev_interrupt(struct amd_ntb_dev *ndev, int vec)
+{
+	dev_dbg(ndev_dev(ndev), "vec %d\n", vec);
+
+	if (vec > (AMD_DB_CNT - 1) || (ndev->msix_vec_count == 1))
+		amd_handle_event(ndev, vec);
+
+	if (vec < AMD_DB_CNT)
+		ntb_db_event(&ndev->ntb, vec);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t ndev_vec_isr(int irq, void *dev)
+{
+	struct amd_ntb_vec *nvec = dev;
+
+	return ndev_interrupt(nvec->ndev, nvec->num);
+}
+
+static irqreturn_t ndev_irq_isr(int irq, void *dev)
+{
+	struct amd_ntb_dev *ndev = dev;
+
+	return ndev_interrupt(ndev, irq - ndev_pdev(ndev)->irq);
+}
+
+static int ndev_init_isr(struct amd_ntb_dev *ndev,
+			 int msix_min, int msix_max)
+{
+	struct pci_dev *pdev;
+	int rc, i, msix_count, node;
+
+	pdev = ndev_pdev(ndev);
+
+	node = dev_to_node(&pdev->dev);
+
+	ndev->db_mask = ndev->db_valid_mask;
+
+	/* Try to set up msix irq */
+	ndev->vec = kzalloc_node(msix_max * sizeof(*ndev->vec),
+				 GFP_KERNEL, node);
+	if (!ndev->vec)
+		goto err_msix_vec_alloc;
+
+	ndev->msix = kzalloc_node(msix_max * sizeof(*ndev->msix),
+				  GFP_KERNEL, node);
+	if (!ndev->msix)
+		goto err_msix_alloc;
+
+	for (i = 0; i < msix_max; ++i)
+		ndev->msix[i].entry = i;
+
+	msix_count = pci_enable_msix_range(pdev, ndev->msix,
+					   msix_min, msix_max);
+	if (msix_count < 0)
+		goto err_msix_enable;
+
+	/* NOTE: Disable MSIX if msix count is less than 16 because of
+	 * hardware limitation.
+	 */
+	if (msix_count < msix_min) {
+		pci_disable_msix(pdev);
+		goto err_msix_enable;
+	}
+
+	for (i = 0; i < msix_count; ++i) {
+		ndev->vec[i].ndev = ndev;
+		ndev->vec[i].num = i;
+		rc = request_irq(ndev->msix[i].vector, ndev_vec_isr, 0,
+				 "ndev_vec_isr", &ndev->vec[i]);
+		if (rc)
+			goto err_msix_request;
+	}
+
+	dev_dbg(ndev_dev(ndev), "Using msix interrupts\n");
+	ndev->db_count = msix_min;
+	ndev->msix_vec_count = msix_max;
+	return 0;
+
+err_msix_request:
+	while (i-- > 0)
+		free_irq(ndev->msix[i].vector, ndev);
+	pci_disable_msix(pdev);
+err_msix_enable:
+	kfree(ndev->msix);
+err_msix_alloc:
+	kfree(ndev->vec);
+err_msix_vec_alloc:
+	ndev->msix = NULL;
+	ndev->vec = NULL;
+
+	/* Try to set up msi irq */
+	rc = pci_enable_msi(pdev);
+	if (rc)
+		goto err_msi_enable;
+
+	rc = request_irq(pdev->irq, ndev_irq_isr, 0,
+			 "ndev_irq_isr", ndev);
+	if (rc)
+		goto err_msi_request;
+
+	dev_dbg(ndev_dev(ndev), "Using msi interrupts\n");
+	ndev->db_count = 1;
+	ndev->msix_vec_count = 1;
+	return 0;
+
+err_msi_request:
+	pci_disable_msi(pdev);
+err_msi_enable:
+
+	/* Try to set up intx irq */
+	pci_intx(pdev, 1);
+
+	rc = request_irq(pdev->irq, ndev_irq_isr, IRQF_SHARED,
+			 "ndev_irq_isr", ndev);
+	if (rc)
+		goto err_intx_request;
+
+	dev_dbg(ndev_dev(ndev), "Using intx interrupts\n");
+	ndev->db_count = 1;
+	ndev->msix_vec_count = 1;
+	return 0;
+
+err_intx_request:
+	return rc;
+}
+
+static void ndev_deinit_isr(struct amd_ntb_dev *ndev)
+{
+	struct pci_dev *pdev;
+	void __iomem *mmio = ndev->self_mmio;
+	int i;
+
+	pdev = ndev_pdev(ndev);
+
+	/* Mask all doorbell interrupts */
+	ndev->db_mask = ndev->db_valid_mask;
+	writel(ndev->db_mask, mmio + AMD_DBMASK_OFFSET);
+
+	if (ndev->msix) {
+		i = ndev->msix_vec_count;
+		while (i--)
+			free_irq(ndev->msix[i].vector, &ndev->vec[i]);
+		pci_disable_msix(pdev);
+		kfree(ndev->msix);
+		kfree(ndev->vec);
+	} else {
+		free_irq(pdev->irq, ndev);
+		if (pci_dev_msi_enabled(pdev))
+			pci_disable_msi(pdev);
+		else
+			pci_intx(pdev, 0);
+	}
+}
+
+static ssize_t ndev_debugfs_read(struct file *filp, char __user *ubuf,
+				 size_t count, loff_t *offp)
+{
+	struct amd_ntb_dev *ndev;
+	void __iomem *mmio;
+	char *buf;
+	size_t buf_size;
+	ssize_t ret, off;
+	union { u64 v64; u32 v32; u16 v16; } u;
+
+	ndev = filp->private_data;
+	mmio = ndev->self_mmio;
+
+	buf_size = min(count, 0x800ul);
+
+	buf = kmalloc(buf_size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	off = 0;
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "NTB Device Information:\n");
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "Connection Topology -\t%s\n",
+			 ntb_topo_string(ndev->ntb.topo));
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "LNK STA -\t\t%#06x\n", ndev->lnk_sta);
+
+	if (!amd_link_is_up(ndev)) {
+		off += scnprintf(buf + off, buf_size - off,
+				 "Link Status -\t\tDown\n");
+	} else {
+		off += scnprintf(buf + off, buf_size - off,
+				 "Link Status -\t\tUp\n");
+		off += scnprintf(buf + off, buf_size - off,
+				 "Link Speed -\t\tPCI-E Gen %u\n",
+				 NTB_LNK_STA_SPEED(ndev->lnk_sta));
+		off += scnprintf(buf + off, buf_size - off,
+				 "Link Width -\t\tx%u\n",
+				 NTB_LNK_STA_WIDTH(ndev->lnk_sta));
+	}
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "Memory Window Count -\t%u\n", ndev->mw_count);
+	off += scnprintf(buf + off, buf_size - off,
+			 "Scratchpad Count -\t%u\n", ndev->spad_count);
+	off += scnprintf(buf + off, buf_size - off,
+			 "Doorbell Count -\t%u\n", ndev->db_count);
+	off += scnprintf(buf + off, buf_size - off,
+			 "MSIX Vector Count -\t%u\n", ndev->msix_vec_count);
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "Doorbell Valid Mask -\t%#llx\n", ndev->db_valid_mask);
+
+	u.v32 = readl(ndev->self_mmio + AMD_DBMASK_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "Doorbell Mask -\t\t\t%#06x\n", u.v32);
+
+	u.v32 = readl(mmio + AMD_DBSTAT_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "Doorbell Bell -\t\t\t%#06x\n", u.v32);
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "\nNTB Incoming XLAT:\n");
+
+	u.v64 = read64(mmio + AMD_BAR1XLAT_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "XLAT1 -\t\t%#018llx\n", u.v64);
+
+	u.v64 = read64(ndev->self_mmio + AMD_BAR23XLAT_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "XLAT23 -\t\t%#018llx\n", u.v64);
+
+	u.v64 = read64(ndev->self_mmio + AMD_BAR45XLAT_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "XLAT45 -\t\t%#018llx\n", u.v64);
+
+	u.v32 = readl(mmio + AMD_BAR1LMT_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "LMT1 -\t\t\t%#06x\n", u.v32);
+
+	u.v64 = read64(ndev->self_mmio + AMD_BAR23LMT_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "LMT23 -\t\t\t%#018llx\n", u.v64);
+
+	u.v64 = read64(ndev->self_mmio + AMD_BAR45LMT_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "LMT45 -\t\t\t%#018llx\n", u.v64);
+
+	ret = simple_read_from_buffer(ubuf, count, offp, buf, off);
+	kfree(buf);
+	return ret;
+}
+
+static void ndev_init_debugfs(struct amd_ntb_dev *ndev)
+{
+	if (!debugfs_dir) {
+		ndev->debugfs_dir = NULL;
+		ndev->debugfs_info = NULL;
+	} else {
+		ndev->debugfs_dir =
+			debugfs_create_dir(ndev_name(ndev), debugfs_dir);
+		if (!ndev->debugfs_dir)
+			ndev->debugfs_info = NULL;
+		else
+			ndev->debugfs_info =
+				debugfs_create_file("info", S_IRUSR,
+						    ndev->debugfs_dir, ndev,
+						    &amd_ntb_debugfs_info);
+	}
+}
+
+static void ndev_deinit_debugfs(struct amd_ntb_dev *ndev)
+{
+	debugfs_remove_recursive(ndev->debugfs_dir);
+}
+
+static inline void ndev_init_struct(struct amd_ntb_dev *ndev,
+				    struct pci_dev *pdev)
+{
+	ndev->ntb.pdev = pdev;
+	ndev->ntb.topo = NTB_TOPO_NONE;
+	ndev->ntb.ops = &amd_ntb_ops;
+	ndev->int_mask = AMD_EVENT_INTMASK;
+	spin_lock_init(&ndev->db_mask_lock);
+}
+
+static int amd_poll_link(struct amd_ntb_dev *ndev)
+{
+	void __iomem *mmio = ndev->peer_mmio;
+	u32 reg, stat;
+	int rc;
+
+	reg = readl(mmio + AMD_SIDEINFO_OFFSET);
+	reg &= NTB_LIN_STA_ACTIVE_BIT;
+
+	dev_dbg(ndev_dev(ndev), "%s: reg_val = 0x%x.\n", __func__, reg);
+
+	if (reg == ndev->cntl_sta)
+		return 0;
+
+	ndev->cntl_sta = reg;
+
+	rc = pci_read_config_dword(ndev->ntb.pdev,
+				   AMD_LINK_STATUS_OFFSET, &stat);
+	if (rc)
+		return 0;
+	ndev->lnk_sta = stat;
+
+	return 1;
+}
+
+static void amd_link_hb(struct work_struct *work)
+{
+	struct amd_ntb_dev *ndev = hb_ndev(work);
+
+	if (amd_poll_link(ndev))
+		ntb_link_event(&ndev->ntb);
+
+	if (!amd_link_is_up(ndev))
+		schedule_delayed_work(&ndev->hb_timer, AMD_LINK_HB_TIMEOUT);
+}
+
+static int amd_init_isr(struct amd_ntb_dev *ndev)
+{
+	return ndev_init_isr(ndev, AMD_DB_CNT, AMD_MSIX_VECTOR_CNT);
+}
+
+static void amd_init_side_info(struct amd_ntb_dev *ndev)
+{
+	void __iomem *mmio = ndev->self_mmio;
+	unsigned int reg;
+
+	reg = readl(mmio + AMD_SIDEINFO_OFFSET);
+	if (!(reg & AMD_SIDE_READY)) {
+		reg |= AMD_SIDE_READY;
+		writel(reg, mmio + AMD_SIDEINFO_OFFSET);
+	}
+}
+
+static void amd_deinit_side_info(struct amd_ntb_dev *ndev)
+{
+	void __iomem *mmio = ndev->self_mmio;
+	unsigned int reg;
+
+	reg = readl(mmio + AMD_SIDEINFO_OFFSET);
+	if (reg & AMD_SIDE_READY) {
+		reg &= ~AMD_SIDE_READY;
+		writel(reg, mmio + AMD_SIDEINFO_OFFSET);
+		readl(mmio + AMD_SIDEINFO_OFFSET);
+	}
+}
+
+static int amd_init_ntb(struct amd_ntb_dev *ndev)
+{
+	void __iomem *mmio = ndev->self_mmio;
+
+	ndev->mw_count = AMD_MW_CNT;
+	ndev->spad_count = AMD_SPADS_CNT;
+	ndev->db_count = AMD_DB_CNT;
+
+	switch (ndev->ntb.topo) {
+	case NTB_TOPO_PRI:
+	case NTB_TOPO_SEC:
+		ndev->spad_count >>= 1;
+		if (ndev->ntb.topo == NTB_TOPO_PRI) {
+			ndev->self_spad = 0;
+			ndev->peer_spad = 0x20;
+		} else {
+			ndev->self_spad = 0x20;
+			ndev->peer_spad = 0;
+		}
+
+		INIT_DELAYED_WORK(&ndev->hb_timer, amd_link_hb);
+		schedule_delayed_work(&ndev->hb_timer, AMD_LINK_HB_TIMEOUT);
+
+		break;
+	default:
+		dev_err(ndev_dev(ndev), "AMD NTB does not support B2B mode.\n");
+		return -EINVAL;
+	}
+
+	ndev->db_valid_mask = BIT_ULL(ndev->db_count) - 1;
+
+	/* Mask event interrupts */
+	writel(ndev->int_mask, mmio + AMD_INTMASK_OFFSET);
+
+	return 0;
+}
+
+static enum ntb_topo amd_get_topo(struct amd_ntb_dev *ndev)
+{
+	void __iomem *mmio = ndev->self_mmio;
+	u32 info;
+
+	info = readl(mmio + AMD_SIDEINFO_OFFSET);
+	if (info & AMD_SIDE_MASK)
+		return NTB_TOPO_SEC;
+	else
+		return NTB_TOPO_PRI;
+}
+
+static int amd_init_dev(struct amd_ntb_dev *ndev)
+{
+	struct pci_dev *pdev;
+	int rc = 0;
+
+	pdev = ndev_pdev(ndev);
+
+	ndev->ntb.topo = amd_get_topo(ndev);
+	dev_dbg(ndev_dev(ndev), "AMD NTB topo is %s\n",
+		ntb_topo_string(ndev->ntb.topo));
+
+	rc = amd_init_ntb(ndev);
+	if (rc)
+		return rc;
+
+	rc = amd_init_isr(ndev);
+	if (rc) {
+		dev_err(ndev_dev(ndev), "fail to init isr.\n");
+		return rc;
+	}
+
+	ndev->db_valid_mask = BIT_ULL(ndev->db_count) - 1;
+
+	return 0;
+}
+
+static void amd_deinit_dev(struct amd_ntb_dev *ndev)
+{
+	cancel_delayed_work_sync(&ndev->hb_timer);
+
+	ndev_deinit_isr(ndev);
+}
+
+static int amd_ntb_init_pci(struct amd_ntb_dev *ndev,
+			    struct pci_dev *pdev)
+{
+	int rc;
+
+	pci_set_drvdata(pdev, ndev);
+
+	rc = pci_enable_device(pdev);
+	if (rc)
+		goto err_pci_enable;
+
+	rc = pci_request_regions(pdev, NTB_NAME);
+	if (rc)
+		goto err_pci_regions;
+
+	pci_set_master(pdev);
+
+	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 err_dma_mask;
+		dev_warn(ndev_dev(ndev), "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 err_dma_mask;
+		dev_warn(ndev_dev(ndev), "Cannot DMA consistent highmem\n");
+	}
+
+	ndev->self_mmio = pci_iomap(pdev, 0, 0);
+	if (!ndev->self_mmio) {
+		rc = -EIO;
+		goto err_dma_mask;
+	}
+	ndev->peer_mmio = ndev->self_mmio + AMD_PEER_OFFSET;
+
+	return 0;
+
+err_dma_mask:
+	pci_clear_master(pdev);
+err_pci_regions:
+	pci_disable_device(pdev);
+err_pci_enable:
+	pci_set_drvdata(pdev, NULL);
+	return rc;
+}
+
+static void amd_ntb_deinit_pci(struct amd_ntb_dev *ndev)
+{
+	struct pci_dev *pdev = ndev_pdev(ndev);
+
+	pci_iounmap(pdev, ndev->self_mmio);
+
+	pci_clear_master(pdev);
+	pci_release_regions(pdev);
+	pci_disable_device(pdev);
+	pci_set_drvdata(pdev, NULL);
+}
+
+static int amd_ntb_pci_probe(struct pci_dev *pdev,
+			     const struct pci_device_id *id)
+{
+	struct amd_ntb_dev *ndev;
+	int rc, node;
+
+	node = dev_to_node(&pdev->dev);
+
+	ndev = kzalloc_node(sizeof(*ndev), GFP_KERNEL, node);
+	if (!ndev) {
+		rc = -ENOMEM;
+		goto err_ndev;
+	}
+
+	ndev_init_struct(ndev, pdev);
+
+	rc = amd_ntb_init_pci(ndev, pdev);
+	if (rc)
+		goto err_init_pci;
+
+	rc = amd_init_dev(ndev);
+	if (rc)
+		goto err_init_dev;
+
+	/* write side info */
+	amd_init_side_info(ndev);
+
+	amd_poll_link(ndev);
+
+	ndev_init_debugfs(ndev);
+
+	rc = ntb_register_device(&ndev->ntb);
+	if (rc)
+		goto err_register;
+
+	dev_info(&pdev->dev, "NTB device registered.\n");
+
+	return 0;
+
+err_register:
+	ndev_deinit_debugfs(ndev);
+	amd_deinit_dev(ndev);
+err_init_dev:
+	amd_ntb_deinit_pci(ndev);
+err_init_pci:
+	kfree(ndev);
+err_ndev:
+	return rc;
+}
+
+static void amd_ntb_pci_remove(struct pci_dev *pdev)
+{
+	struct amd_ntb_dev *ndev = pci_get_drvdata(pdev);
+
+	ntb_unregister_device(&ndev->ntb);
+	ndev_deinit_debugfs(ndev);
+	amd_deinit_side_info(ndev);
+	amd_deinit_dev(ndev);
+	amd_ntb_deinit_pci(ndev);
+	kfree(ndev);
+}
+
+static const struct file_operations amd_ntb_debugfs_info = {
+	.owner = THIS_MODULE,
+	.open = simple_open,
+	.read = ndev_debugfs_read,
+};
+
+static const struct pci_device_id amd_ntb_pci_tbl[] = {
+	{PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_NTB)},
+	{0}
+};
+MODULE_DEVICE_TABLE(pci, amd_ntb_pci_tbl);
+
+static struct pci_driver amd_ntb_pci_driver = {
+	.name		= KBUILD_MODNAME,
+	.id_table	= amd_ntb_pci_tbl,
+	.probe		= amd_ntb_pci_probe,
+	.remove		= amd_ntb_pci_remove,
+};
+
+static int __init amd_ntb_pci_driver_init(void)
+{
+	pr_info("%s %s\n", NTB_DESC, NTB_VER);
+
+	if (debugfs_initialized())
+		debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
+
+	return pci_register_driver(&amd_ntb_pci_driver);
+}
+module_init(amd_ntb_pci_driver_init);
+
+static void __exit amd_ntb_pci_driver_exit(void)
+{
+	pci_unregister_driver(&amd_ntb_pci_driver);
+	debugfs_remove_recursive(debugfs_dir);
+}
+module_exit(amd_ntb_pci_driver_exit);

drivers/ntb/hw/amd/ntb_hw_amd.h

+/*
+ * 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) 2016 Advanced Micro Devices, Inc. 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) 2016 Advanced Micro Devices, Inc. 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 AMD 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.
+ *
+ * AMD PCIe NTB Linux driver
+ *
+ * Contact Information:
+ * Xiangliang Yu <Xiangliang.Yu@amd.com>
+ */
+
+#ifndef NTB_HW_AMD_H
+#define NTB_HW_AMD_H
+
+#include <linux/ntb.h>
+#include <linux/pci.h>
+
+#define PCI_DEVICE_ID_AMD_NTB	0x145B
+#define AMD_LINK_HB_TIMEOUT	msecs_to_jiffies(1000)
+#define AMD_LINK_STATUS_OFFSET	0x68
+#define NTB_LIN_STA_ACTIVE_BIT	0x00000002
+#define NTB_LNK_STA_SPEED_MASK	0x000F0000
+#define NTB_LNK_STA_WIDTH_MASK	0x03F00000
+#define NTB_LNK_STA_ACTIVE(x)	(!!((x) & NTB_LIN_STA_ACTIVE_BIT))
+#define NTB_LNK_STA_SPEED(x)	(((x) & NTB_LNK_STA_SPEED_MASK) >> 16)
+#define NTB_LNK_STA_WIDTH(x)	(((x) & NTB_LNK_STA_WIDTH_MASK) >> 20)
+
+#ifndef read64
+#ifdef readq
+#define read64 readq
+#else
+#define read64 _read64
+static inline u64 _read64(void __iomem *mmio)
+{
+	u64 low, high;
+
+	low = readl(mmio);
+	high = readl(mmio + sizeof(u32));
+	return low | (high << 32);
+}
+#endif
+#endif
+
+#ifndef write64
+#ifdef writeq
+#define write64 writeq
+#else
+#define write64 _write64
+static inline void _write64(u64 val, void __iomem *mmio)
+{
+	writel(val, mmio);
+	writel(val >> 32, mmio + sizeof(u32));
+}
+#endif
+#endif
+
+enum {
+	/* AMD NTB Capability */
+	AMD_MW_CNT		= 3,
+	AMD_DB_CNT		= 16,
+	AMD_MSIX_VECTOR_CNT	= 24,
+	AMD_SPADS_CNT		= 16,
+
+	/*  AMD NTB register offset */
+	AMD_CNTL_OFFSET		= 0x200,
+
+	/* NTB control register bits */
+	PMM_REG_CTL		= BIT(21),
+	SMM_REG_CTL		= BIT(20),
+	SMM_REG_ACC_PATH	= BIT(18),
+	PMM_REG_ACC_PATH	= BIT(17),
+	NTB_CLK_EN		= BIT(16),
+
+	AMD_STA_OFFSET		= 0x204,
+	AMD_PGSLV_OFFSET	= 0x208,
+	AMD_SPAD_MUX_OFFSET	= 0x20C,
+	AMD_SPAD_OFFSET		= 0x210,
+	AMD_RSMU_HCID		= 0x250,
+	AMD_RSMU_SIID		= 0x254,
+	AMD_PSION_OFFSET	= 0x300,
+	AMD_SSION_OFFSET	= 0x330,
+	AMD_MMINDEX_OFFSET	= 0x400,
+	AMD_MMDATA_OFFSET	= 0x404,
+	AMD_SIDEINFO_OFFSET	= 0x408,
+
+	AMD_SIDE_MASK		= BIT(0),
+	AMD_SIDE_READY		= BIT(1),
+
+	/* limit register */
+	AMD_ROMBARLMT_OFFSET	= 0x410,
+	AMD_BAR1LMT_OFFSET	= 0x414,
+	AMD_BAR23LMT_OFFSET	= 0x418,
+	AMD_BAR45LMT_OFFSET	= 0x420,
+	/* xlat address */
+	AMD_POMBARXLAT_OFFSET	= 0x428,
+	AMD_BAR1XLAT_OFFSET	= 0x430,
+	AMD_BAR23XLAT_OFFSET	= 0x438,
+	AMD_BAR45XLAT_OFFSET	= 0x440,
+	/* doorbell and interrupt */
+	AMD_DBFM_OFFSET		= 0x450,
+	AMD_DBREQ_OFFSET	= 0x454,
+	AMD_MIRRDBSTAT_OFFSET	= 0x458,
+	AMD_DBMASK_OFFSET	= 0x45C,
+	AMD_DBSTAT_OFFSET	= 0x460,
+	AMD_INTMASK_OFFSET	= 0x470,
+	AMD_INTSTAT_OFFSET	= 0x474,
+
+	/* event type */
+	AMD_PEER_FLUSH_EVENT	= BIT(0),
+	AMD_PEER_RESET_EVENT	= BIT(1),
+	AMD_PEER_D3_EVENT	= BIT(2),
+	AMD_PEER_PMETO_EVENT	= BIT(3),
+	AMD_PEER_D0_EVENT	= BIT(4),
+	AMD_EVENT_INTMASK	= (AMD_PEER_FLUSH_EVENT |
+				AMD_PEER_RESET_EVENT | AMD_PEER_D3_EVENT |
+				AMD_PEER_PMETO_EVENT | AMD_PEER_D0_EVENT),
+
+	AMD_PMESTAT_OFFSET	= 0x480,
+	AMD_PMSGTRIG_OFFSET	= 0x490,
+	AMD_LTRLATENCY_OFFSET	= 0x494,
+	AMD_FLUSHTRIG_OFFSET	= 0x498,
+
+	/* SMU register*/
+	AMD_SMUACK_OFFSET	= 0x4A0,
+	AMD_SINRST_OFFSET	= 0x4A4,
+	AMD_RSPNUM_OFFSET	= 0x4A8,
+	AMD_SMU_SPADMUTEX	= 0x4B0,
+	AMD_SMU_SPADOFFSET	= 0x4B4,
+
+	AMD_PEER_OFFSET		= 0x400,
+};
+
+struct amd_ntb_dev;
+
+struct amd_ntb_vec {
+	struct amd_ntb_dev	*ndev;
+	int			num;
+};
+
+struct amd_ntb_dev {
+	struct ntb_dev ntb;
+
+	u32 ntb_side;
+	u32 lnk_sta;
+	u32 cntl_sta;
+	u32 peer_sta;
+
+	unsigned char mw_count;
+	unsigned char spad_count;
+	unsigned char db_count;
+	unsigned char msix_vec_count;
+
+	u64 db_valid_mask;
+	u64 db_mask;
+	u32 int_mask;
+
+	struct msix_entry *msix;
+	struct amd_ntb_vec *vec;
+
+	/* synchronize rmw access of db_mask and hw reg */
+	spinlock_t db_mask_lock;
+
+	void __iomem *self_mmio;
+	void __iomem *peer_mmio;
+	unsigned int self_spad;
+	unsigned int peer_spad;
+
+	struct delayed_work hb_timer;
+
+	struct dentry *debugfs_dir;
+	struct dentry *debugfs_info;
+};
+
+#define ndev_pdev(ndev) ((ndev)->ntb.pdev)
+#define ndev_name(ndev) pci_name(ndev_pdev(ndev))
+#define ndev_dev(ndev) (&ndev_pdev(ndev)->dev)
+#define ntb_ndev(__ntb) container_of(__ntb, struct amd_ntb_dev, ntb)
+#define hb_ndev(__work) container_of(__work, struct amd_ntb_dev, hb_timer.work)
+
+#endif

drivers/ntb/hw/intel/ntb_hw_intel.c

@@ -875,7 +875,7 @@ static int intel_ntb_mw_set_trans(struct ntb_dev *ntb, int idx,
 	limit_reg = bar2_off(ndev->xlat_reg->bar2_limit, bar);
 
 	if (bar < 4 || !ndev->bar4_split) {
-		base = ioread64(mmio + base_reg);
+		base = ioread64(mmio + base_reg) & NTB_BAR_MASK_64;
 
 		/* Set the limit if supported, if size is not mw_size */
 		if (limit_reg && size != mw_size)
@@ -906,7 +906,7 @@ static int intel_ntb_mw_set_trans(struct ntb_dev *ntb, int idx,
 		if ((addr + size) & (~0ull << 32))
 			return -EINVAL;
 
-		base = ioread32(mmio + base_reg);
+		base = ioread32(mmio + base_reg) & NTB_BAR_MASK_32;
 
 		/* Set the limit if supported, if size is not mw_size */
 		if (limit_reg && size != mw_size)

drivers/ntb/hw/intel/ntb_hw_intel.h

@@ -245,6 +245,9 @@
 #define NTB_UNSAFE_DB			BIT_ULL(0)
 #define NTB_UNSAFE_SPAD			BIT_ULL(1)
 
+#define NTB_BAR_MASK_64			~(0xfull)
+#define NTB_BAR_MASK_32			~(0xfu)
+
 struct intel_ntb_dev;
 
 struct intel_ntb_reg {
@@ -334,7 +337,8 @@ struct intel_ntb_dev {
 #define ndev_pdev(ndev) ((ndev)->ntb.pdev)
 #define ndev_name(ndev) pci_name(ndev_pdev(ndev))
 #define ndev_dev(ndev) (&ndev_pdev(ndev)->dev)
-#define ntb_ndev(ntb) container_of(ntb, struct intel_ntb_dev, ntb)
-#define hb_ndev(work) container_of(work, struct intel_ntb_dev, hb_timer.work)
+#define ntb_ndev(__ntb) container_of(__ntb, struct intel_ntb_dev, ntb)
+#define hb_ndev(__work) container_of(__work, struct intel_ntb_dev, \
+				     hb_timer.work)
 
 #endif

drivers/ntb/ntb_transport.c

@@ -171,12 +171,14 @@ struct ntb_transport_qp {
 	u64 rx_err_ver;
 	u64 rx_memcpy;
 	u64 rx_async;
+	u64 dma_rx_prep_err;
 	u64 tx_bytes;
 	u64 tx_pkts;
 	u64 tx_ring_full;
 	u64 tx_err_no_buf;
 	u64 tx_memcpy;
 	u64 tx_async;
+	u64 dma_tx_prep_err;
 };
 
 struct ntb_transport_mw {
@@ -249,6 +251,8 @@ enum {
 #define QP_TO_MW(nt, qp)	((qp) % nt->mw_count)
 #define NTB_QP_DEF_NUM_ENTRIES	100
 #define NTB_LINK_DOWN_TIMEOUT	10
+#define DMA_RETRIES		20
+#define DMA_OUT_RESOURCE_TO	50
 
 static void ntb_transport_rxc_db(unsigned long data);
 static const struct ntb_ctx_ops ntb_transport_ops;
@@ -501,6 +505,12 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 			       "free tx - \t%u\n",
 			       ntb_transport_tx_free_entry(qp));
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "DMA tx prep err - \t%llu\n",
+			       qp->dma_tx_prep_err);
+	out_offset += snprintf(buf + out_offset, out_count - out_offset,
+			       "DMA rx prep err - \t%llu\n",
+			       qp->dma_rx_prep_err);
 
 	out_offset += snprintf(buf + out_offset, out_count - out_offset,
 			       "\n");
@@ -726,6 +736,8 @@ static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
 	qp->tx_err_no_buf = 0;
 	qp->tx_memcpy = 0;
 	qp->tx_async = 0;
+	qp->dma_tx_prep_err = 0;
+	qp->dma_rx_prep_err = 0;
 }
 
 static void ntb_qp_link_cleanup(struct ntb_transport_qp *qp)
@@ -1228,6 +1240,7 @@ static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset)
 	struct dmaengine_unmap_data *unmap;
 	dma_cookie_t cookie;
 	void *buf = entry->buf;
+	int retries = 0;
 
 	len = entry->len;
 
@@ -1263,11 +1276,21 @@ static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset)
 
 	unmap->from_cnt = 1;
 
-	txd = device->device_prep_dma_memcpy(chan, unmap->addr[1],
-					     unmap->addr[0], len,
-					     DMA_PREP_INTERRUPT);
-	if (!txd)
+	for (retries = 0; retries < DMA_RETRIES; retries++) {
+		txd = device->device_prep_dma_memcpy(chan, unmap->addr[1],
+						     unmap->addr[0], len,
+						     DMA_PREP_INTERRUPT);
+		if (txd)
+			break;
+
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout(DMA_OUT_RESOURCE_TO);
+	}
+
+	if (!txd) {
+		qp->dma_rx_prep_err++;
 		goto err_get_unmap;
+	}
 
 	txd->callback = ntb_rx_copy_callback;
 	txd->callback_param = entry;
@@ -1460,6 +1483,7 @@ static void ntb_async_tx(struct ntb_transport_qp *qp,
 	void __iomem *offset;
 	size_t len = entry->len;
 	void *buf = entry->buf;
+	int retries = 0;
 
 	offset = qp->tx_mw + qp->tx_max_frame * qp->tx_index;
 	hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header);
@@ -1494,10 +1518,20 @@ static void ntb_async_tx(struct ntb_transport_qp *qp,
 
 	unmap->to_cnt = 1;
 
-	txd = device->device_prep_dma_memcpy(chan, dest, unmap->addr[0], len,
-					     DMA_PREP_INTERRUPT);
-	if (!txd)
+	for (retries = 0; retries < DMA_RETRIES; retries++) {
+		txd = device->device_prep_dma_memcpy(chan, dest, unmap->addr[0],
+						     len, DMA_PREP_INTERRUPT);
+		if (txd)
+			break;
+
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout(DMA_OUT_RESOURCE_TO);
+	}
+
+	if (!txd) {
+		qp->dma_tx_prep_err++;
 		goto err_get_unmap;
+	}
 
 	txd->callback = ntb_tx_copy_callback;
 	txd->callback_param = entry;
@@ -1532,7 +1566,7 @@ static int ntb_process_tx(struct ntb_transport_qp *qp,
 
 	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);
+			qp->tx_handler(qp, qp->cb_data, NULL, -EIO);
 
 		ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
 			     &qp->tx_free_q);

drivers/ntb/test/Kconfig

@@ -17,3 +17,11 @@ config NTB_TOOL
 	 functioning at a basic level.
 
 	 If unsure, say N.
+
+config NTB_PERF
+	tristate "NTB RAW Perf Measuring Tool"
+	help
+	 This is a tool to measure raw NTB performance by transferring data
+	 to and from the window without additional software interaction.
+
+	 If unsure, say N.

drivers/ntb/test/Makefile

 obj-$(CONFIG_NTB_PINGPONG) += ntb_pingpong.o
 obj-$(CONFIG_NTB_TOOL) += ntb_tool.o
+obj-$(CONFIG_NTB_PERF) += ntb_perf.o

drivers/ntb/test/ntb_perf.c

+/*
+ * 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) 2015 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) 2015 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.
+ *
+ *   PCIe NTB Perf Linux driver
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/time.h>
+#include <linux/timer.h>
+#include <linux/dma-mapping.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/debugfs.h>
+#include <linux/dmaengine.h>
+#include <linux/delay.h>
+#include <linux/sizes.h>
+#include <linux/ntb.h>
+
+#define DRIVER_NAME		"ntb_perf"
+#define DRIVER_DESCRIPTION	"PCIe NTB Performance Measurement Tool"
+
+#define DRIVER_LICENSE		"Dual BSD/GPL"
+#define DRIVER_VERSION		"1.0"
+#define DRIVER_AUTHOR		"Dave Jiang <dave.jiang@intel.com>"
+
+#define PERF_LINK_DOWN_TIMEOUT	10
+#define PERF_VERSION		0xffff0001
+#define MAX_THREADS		32
+#define MAX_TEST_SIZE		SZ_1M
+#define MAX_SRCS		32
+#define DMA_OUT_RESOURCE_TO	50
+#define DMA_RETRIES		20
+#define SZ_4G			(1ULL << 32)
+#define MAX_SEG_ORDER		20 /* no larger than 1M for kmalloc buffer */
+
+MODULE_LICENSE(DRIVER_LICENSE);
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESCRIPTION);
+
+static struct dentry *perf_debugfs_dir;
+
+static unsigned int seg_order = 19; /* 512K */
+module_param(seg_order, uint, 0644);
+MODULE_PARM_DESC(seg_order, "size order [n^2] of buffer segment for testing");
+
+static unsigned int run_order = 32; /* 4G */
+module_param(run_order, uint, 0644);
+MODULE_PARM_DESC(run_order, "size order [n^2] of total data to transfer");
+
+static bool use_dma; /* default to 0 */
+module_param(use_dma, bool, 0644);
+MODULE_PARM_DESC(use_dma, "Using DMA engine to measure performance");
+
+struct perf_mw {
+	phys_addr_t	phys_addr;
+	resource_size_t	phys_size;
+	resource_size_t	xlat_align;
+	resource_size_t	xlat_align_size;
+	void __iomem	*vbase;
+	size_t		xlat_size;
+	size_t		buf_size;
+	void		*virt_addr;
+	dma_addr_t	dma_addr;
+};
+
+struct perf_ctx;
+
+struct pthr_ctx {
+	struct task_struct	*thread;
+	struct perf_ctx		*perf;
+	atomic_t		dma_sync;
+	struct dma_chan		*dma_chan;
+	int			dma_prep_err;
+	int			src_idx;
+	void			*srcs[MAX_SRCS];
+};
+
+struct perf_ctx {
+	struct ntb_dev		*ntb;
+	spinlock_t		db_lock;
+	struct perf_mw		mw;
+	bool			link_is_up;
+	struct work_struct	link_cleanup;
+	struct delayed_work	link_work;
+	struct dentry		*debugfs_node_dir;
+	struct dentry		*debugfs_run;
+	struct dentry		*debugfs_threads;
+	u8			perf_threads;
+	bool			run;
+	struct pthr_ctx		pthr_ctx[MAX_THREADS];
+	atomic_t		tsync;
+};
+
+enum {
+	VERSION = 0,
+	MW_SZ_HIGH,
+	MW_SZ_LOW,
+	SPAD_MSG,
+	SPAD_ACK,
+	MAX_SPAD
+};
+
+static void perf_link_event(void *ctx)
+{
+	struct perf_ctx *perf = ctx;
+
+	if (ntb_link_is_up(perf->ntb, NULL, NULL) == 1)
+		schedule_delayed_work(&perf->link_work, 2*HZ);
+	else
+		schedule_work(&perf->link_cleanup);
+}
+
+static void perf_db_event(void *ctx, int vec)
+{
+	struct perf_ctx *perf = ctx;
+	u64 db_bits, db_mask;
+
+	db_mask = ntb_db_vector_mask(perf->ntb, vec);
+	db_bits = ntb_db_read(perf->ntb);
+
+	dev_dbg(&perf->ntb->dev, "doorbell vec %d mask %#llx bits %#llx\n",
+		vec, db_mask, db_bits);
+}
+
+static const struct ntb_ctx_ops perf_ops = {
+	.link_event = perf_link_event,
+	.db_event = perf_db_event,
+};
+
+static void perf_copy_callback(void *data)
+{
+	struct pthr_ctx *pctx = data;
+
+	atomic_dec(&pctx->dma_sync);
+}
+
+static ssize_t perf_copy(struct pthr_ctx *pctx, char *dst,
+			 char *src, size_t size)
+{
+	struct perf_ctx *perf = pctx->perf;
+	struct dma_async_tx_descriptor *txd;
+	struct dma_chan *chan = pctx->dma_chan;
+	struct dma_device *device;
+	struct dmaengine_unmap_data *unmap;
+	dma_cookie_t cookie;
+	size_t src_off, dst_off;
+	struct perf_mw *mw = &perf->mw;
+	u64 vbase, dst_vaddr;
+	dma_addr_t dst_phys;
+	int retries = 0;
+
+	if (!use_dma) {
+		memcpy_toio(dst, src, size);
+		return size;
+	}
+
+	if (!chan) {
+		dev_err(&perf->ntb->dev, "DMA engine does not exist\n");
+		return -EINVAL;
+	}
+
+	device = chan->device;
+	src_off = (size_t)src & ~PAGE_MASK;
+	dst_off = (size_t)dst & ~PAGE_MASK;
+
+	if (!is_dma_copy_aligned(device, src_off, dst_off, size))
+		return -ENODEV;
+
+	vbase = (u64)(u64 *)mw->vbase;
+	dst_vaddr = (u64)(u64 *)dst;
+	dst_phys = mw->phys_addr + (dst_vaddr - vbase);
+
+	unmap = dmaengine_get_unmap_data(device->dev, 1, GFP_NOWAIT);
+	if (!unmap)
+		return -ENOMEM;
+
+	unmap->len = size;
+	unmap->addr[0] = dma_map_page(device->dev, virt_to_page(src),
+				      src_off, size, DMA_TO_DEVICE);
+	if (dma_mapping_error(device->dev, unmap->addr[0]))
+		goto err_get_unmap;
+
+	unmap->to_cnt = 1;
+
+	do {
+		txd = device->device_prep_dma_memcpy(chan, dst_phys,
+						     unmap->addr[0],
+						     size, DMA_PREP_INTERRUPT);
+		if (!txd) {
+			set_current_state(TASK_INTERRUPTIBLE);
+			schedule_timeout(DMA_OUT_RESOURCE_TO);
+		}
+	} while (!txd && (++retries < DMA_RETRIES));
+
+	if (!txd) {
+		pctx->dma_prep_err++;
+		goto err_get_unmap;
+	}
+
+	txd->callback = perf_copy_callback;
+	txd->callback_param = pctx;
+	dma_set_unmap(txd, unmap);
+
+	cookie = dmaengine_submit(txd);
+	if (dma_submit_error(cookie))
+		goto err_set_unmap;
+
+	atomic_inc(&pctx->dma_sync);
+	dma_async_issue_pending(chan);
+
+	return size;
+
+err_set_unmap:
+	dmaengine_unmap_put(unmap);
+err_get_unmap:
+	dmaengine_unmap_put(unmap);
+	return 0;
+}
+
+static int perf_move_data(struct pthr_ctx *pctx, char *dst, char *src,
+			  u64 buf_size, u64 win_size, u64 total)
+{
+	int chunks, total_chunks, i;
+	int copied_chunks = 0;
+	u64 copied = 0, result;
+	char *tmp = dst;
+	u64 perf, diff_us;
+	ktime_t kstart, kstop, kdiff;
+
+	chunks = div64_u64(win_size, buf_size);
+	total_chunks = div64_u64(total, buf_size);
+	kstart = ktime_get();
+
+	for (i = 0; i < total_chunks; i++) {
+		result = perf_copy(pctx, tmp, src, buf_size);
+		copied += result;
+		copied_chunks++;
+		if (copied_chunks == chunks) {
+			tmp = dst;
+			copied_chunks = 0;
+		} else
+			tmp += buf_size;
+
+		/* Probably should schedule every 4GB to prevent soft hang. */
+		if (((copied % SZ_4G) == 0) && !use_dma) {
+			set_current_state(TASK_INTERRUPTIBLE);
+			schedule_timeout(1);
+		}
+	}
+
+	if (use_dma) {
+		pr_info("%s: All DMA descriptors submitted\n", current->comm);
+		while (atomic_read(&pctx->dma_sync) != 0)
+			msleep(20);
+	}
+
+	kstop = ktime_get();
+	kdiff = ktime_sub(kstop, kstart);
+	diff_us = ktime_to_us(kdiff);
+
+	pr_info("%s: copied %llu bytes\n", current->comm, copied);
+
+	pr_info("%s: lasted %llu usecs\n", current->comm, diff_us);
+
+	perf = div64_u64(copied, diff_us);
+
+	pr_info("%s: MBytes/s: %llu\n", current->comm, perf);
+
+	return 0;
+}
+
+static bool perf_dma_filter_fn(struct dma_chan *chan, void *node)
+{
+	return dev_to_node(&chan->dev->device) == (int)(unsigned long)node;
+}
+
+static int ntb_perf_thread(void *data)
+{
+	struct pthr_ctx *pctx = data;
+	struct perf_ctx *perf = pctx->perf;
+	struct pci_dev *pdev = perf->ntb->pdev;
+	struct perf_mw *mw = &perf->mw;
+	char *dst;
+	u64 win_size, buf_size, total;
+	void *src;
+	int rc, node, i;
+	struct dma_chan *dma_chan = NULL;
+
+	pr_info("kthread %s starting...\n", current->comm);
+
+	node = dev_to_node(&pdev->dev);
+
+	if (use_dma && !pctx->dma_chan) {
+		dma_cap_mask_t dma_mask;
+
+		dma_cap_zero(dma_mask);
+		dma_cap_set(DMA_MEMCPY, dma_mask);
+		dma_chan = dma_request_channel(dma_mask, perf_dma_filter_fn,
+					       (void *)(unsigned long)node);
+		if (!dma_chan) {
+			pr_warn("%s: cannot acquire DMA channel, quitting\n",
+				current->comm);
+			return -ENODEV;
+		}
+		pctx->dma_chan = dma_chan;
+	}
+
+	for (i = 0; i < MAX_SRCS; i++) {
+		pctx->srcs[i] = kmalloc_node(MAX_TEST_SIZE, GFP_KERNEL, node);
+		if (!pctx->srcs[i]) {
+			rc = -ENOMEM;
+			goto err;
+		}
+	}
+
+	win_size = mw->phys_size;
+	buf_size = 1ULL << seg_order;
+	total = 1ULL << run_order;
+
+	if (buf_size > MAX_TEST_SIZE)
+		buf_size = MAX_TEST_SIZE;
+
+	dst = (char *)mw->vbase;
+
+	atomic_inc(&perf->tsync);
+	while (atomic_read(&perf->tsync) != perf->perf_threads)
+		schedule();
+
+	src = pctx->srcs[pctx->src_idx];
+	pctx->src_idx = (pctx->src_idx + 1) & (MAX_SRCS - 1);
+
+	rc = perf_move_data(pctx, dst, src, buf_size, win_size, total);
+
+	atomic_dec(&perf->tsync);
+
+	if (rc < 0) {
+		pr_err("%s: failed\n", current->comm);
+		rc = -ENXIO;
+		goto err;
+	}
+
+	for (i = 0; i < MAX_SRCS; i++) {
+		kfree(pctx->srcs[i]);
+		pctx->srcs[i] = NULL;
+	}
+
+	return 0;
+
+err:
+	for (i = 0; i < MAX_SRCS; i++) {
+		kfree(pctx->srcs[i]);
+		pctx->srcs[i] = NULL;
+	}
+
+	if (dma_chan) {
+		dma_release_channel(dma_chan);
+		pctx->dma_chan = NULL;
+	}
+
+	return rc;
+}
+
+static void perf_free_mw(struct perf_ctx *perf)
+{
+	struct perf_mw *mw = &perf->mw;
+	struct pci_dev *pdev = perf->ntb->pdev;
+
+	if (!mw->virt_addr)
+		return;
+
+	ntb_mw_clear_trans(perf->ntb, 0);
+	dma_free_coherent(&pdev->dev, mw->buf_size,
+			  mw->virt_addr, mw->dma_addr);
+	mw->xlat_size = 0;
+	mw->buf_size = 0;
+	mw->virt_addr = NULL;
+}
+
+static int perf_set_mw(struct perf_ctx *perf, resource_size_t size)
+{
+	struct perf_mw *mw = &perf->mw;
+	size_t xlat_size, buf_size;
+
+	if (!size)
+		return -EINVAL;
+
+	xlat_size = round_up(size, mw->xlat_align_size);
+	buf_size = round_up(size, mw->xlat_align);
+
+	if (mw->xlat_size == xlat_size)
+		return 0;
+
+	if (mw->buf_size)
+		perf_free_mw(perf);
+
+	mw->xlat_size = xlat_size;
+	mw->buf_size = buf_size;
+
+	mw->virt_addr = dma_alloc_coherent(&perf->ntb->pdev->dev, buf_size,
+					   &mw->dma_addr, GFP_KERNEL);
+	if (!mw->virt_addr) {
+		mw->xlat_size = 0;
+		mw->buf_size = 0;
+	}
+
+	return 0;
+}
+
+static void perf_link_work(struct work_struct *work)
+{
+	struct perf_ctx *perf =
+		container_of(work, struct perf_ctx, link_work.work);
+	struct ntb_dev *ndev = perf->ntb;
+	struct pci_dev *pdev = ndev->pdev;
+	u32 val;
+	u64 size;
+	int rc;
+
+	dev_dbg(&perf->ntb->pdev->dev, "%s called\n", __func__);
+
+	size = perf->mw.phys_size;
+	ntb_peer_spad_write(ndev, MW_SZ_HIGH, upper_32_bits(size));
+	ntb_peer_spad_write(ndev, MW_SZ_LOW, lower_32_bits(size));
+	ntb_peer_spad_write(ndev, VERSION, PERF_VERSION);
+
+	/* now read what peer wrote */
+	val = ntb_spad_read(ndev, VERSION);
+	if (val != PERF_VERSION) {
+		dev_dbg(&pdev->dev, "Remote version = %#x\n", val);
+		goto out;
+	}
+
+	val = ntb_spad_read(ndev, MW_SZ_HIGH);
+	size = (u64)val << 32;
+
+	val = ntb_spad_read(ndev, MW_SZ_LOW);
+	size |= val;
+
+	dev_dbg(&pdev->dev, "Remote MW size = %#llx\n", size);
+
+	rc = perf_set_mw(perf, size);
+	if (rc)
+		goto out1;
+
+	perf->link_is_up = true;
+
+	return;
+
+out1:
+	perf_free_mw(perf);
+
+out:
+	if (ntb_link_is_up(ndev, NULL, NULL) == 1)
+		schedule_delayed_work(&perf->link_work,
+				      msecs_to_jiffies(PERF_LINK_DOWN_TIMEOUT));
+}
+
+static void perf_link_cleanup(struct work_struct *work)
+{
+	struct perf_ctx *perf = container_of(work,
+					     struct perf_ctx,
+					     link_cleanup);
+
+	dev_dbg(&perf->ntb->pdev->dev, "%s called\n", __func__);
+
+	if (!perf->link_is_up)
+		cancel_delayed_work_sync(&perf->link_work);
+}
+
+static int perf_setup_mw(struct ntb_dev *ntb, struct perf_ctx *perf)
+{
+	struct perf_mw *mw;
+	int rc;
+
+	mw = &perf->mw;
+
+	rc = ntb_mw_get_range(ntb, 0, &mw->phys_addr, &mw->phys_size,
+			      &mw->xlat_align, &mw->xlat_align_size);
+	if (rc)
+		return rc;
+
+	perf->mw.vbase = ioremap_wc(mw->phys_addr, mw->phys_size);
+	if (!mw->vbase)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static ssize_t debugfs_run_read(struct file *filp, char __user *ubuf,
+				size_t count, loff_t *offp)
+{
+	struct perf_ctx *perf = filp->private_data;
+	char *buf;
+	ssize_t ret, out_offset;
+
+	if (!perf)
+		return 0;
+
+	buf = kmalloc(64, GFP_KERNEL);
+	out_offset = snprintf(buf, 64, "%d\n", perf->run);
+	ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
+	kfree(buf);
+
+	return ret;
+}
+
+static ssize_t debugfs_run_write(struct file *filp, const char __user *ubuf,
+				 size_t count, loff_t *offp)
+{
+	struct perf_ctx *perf = filp->private_data;
+	int node, i;
+
+	if (!perf->link_is_up)
+		return 0;
+
+	if (perf->perf_threads == 0)
+		return 0;
+
+	if (atomic_read(&perf->tsync) == 0)
+		perf->run = false;
+
+	if (perf->run) {
+		/* lets stop the threads */
+		perf->run = false;
+		for (i = 0; i < MAX_THREADS; i++) {
+			if (perf->pthr_ctx[i].thread) {
+				kthread_stop(perf->pthr_ctx[i].thread);
+				perf->pthr_ctx[i].thread = NULL;
+			} else
+				break;
+		}
+	} else {
+		perf->run = true;
+
+		if (perf->perf_threads > MAX_THREADS) {
+			perf->perf_threads = MAX_THREADS;
+			pr_info("Reset total threads to: %u\n", MAX_THREADS);
+		}
+
+		/* no greater than 1M */
+		if (seg_order > MAX_SEG_ORDER) {
+			seg_order = MAX_SEG_ORDER;
+			pr_info("Fix seg_order to %u\n", seg_order);
+		}
+
+		if (run_order < seg_order) {
+			run_order = seg_order;
+			pr_info("Fix run_order to %u\n", run_order);
+		}
+
+		node = dev_to_node(&perf->ntb->pdev->dev);
+		/* launch kernel thread */
+		for (i = 0; i < perf->perf_threads; i++) {
+			struct pthr_ctx *pctx;
+
+			pctx = &perf->pthr_ctx[i];
+			atomic_set(&pctx->dma_sync, 0);
+			pctx->perf = perf;
+			pctx->thread =
+				kthread_create_on_node(ntb_perf_thread,
+						       (void *)pctx,
+						       node, "ntb_perf %d", i);
+			if (pctx->thread)
+				wake_up_process(pctx->thread);
+			else {
+				perf->run = false;
+				for (i = 0; i < MAX_THREADS; i++) {
+					if (pctx->thread) {
+						kthread_stop(pctx->thread);
+						pctx->thread = NULL;
+					}
+				}
+			}
+
+			if (perf->run == false)
+				return -ENXIO;
+		}
+
+	}
+
+	return count;
+}
+
+static const struct file_operations ntb_perf_debugfs_run = {
+	.owner = THIS_MODULE,
+	.open = simple_open,
+	.read = debugfs_run_read,
+	.write = debugfs_run_write,
+};
+
+static int perf_debugfs_setup(struct perf_ctx *perf)
+{
+	struct pci_dev *pdev = perf->ntb->pdev;
+
+	if (!debugfs_initialized())
+		return -ENODEV;
+
+	if (!perf_debugfs_dir) {
+		perf_debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
+		if (!perf_debugfs_dir)
+			return -ENODEV;
+	}
+
+	perf->debugfs_node_dir = debugfs_create_dir(pci_name(pdev),
+						    perf_debugfs_dir);
+	if (!perf->debugfs_node_dir)
+		return -ENODEV;
+
+	perf->debugfs_run = debugfs_create_file("run", S_IRUSR | S_IWUSR,
+						perf->debugfs_node_dir, perf,
+						&ntb_perf_debugfs_run);
+	if (!perf->debugfs_run)
+		return -ENODEV;
+
+	perf->debugfs_threads = debugfs_create_u8("threads", S_IRUSR | S_IWUSR,
+						  perf->debugfs_node_dir,
+						  &perf->perf_threads);
+	if (!perf->debugfs_threads)
+		return -ENODEV;
+
+	return 0;
+}
+
+static int perf_probe(struct ntb_client *client, struct ntb_dev *ntb)
+{
+	struct pci_dev *pdev = ntb->pdev;
+	struct perf_ctx *perf;
+	int node;
+	int rc = 0;
+
+	node = dev_to_node(&pdev->dev);
+
+	perf = kzalloc_node(sizeof(*perf), GFP_KERNEL, node);
+	if (!perf) {
+		rc = -ENOMEM;
+		goto err_perf;
+	}
+
+	perf->ntb = ntb;
+	perf->perf_threads = 1;
+	atomic_set(&perf->tsync, 0);
+	perf->run = false;
+	spin_lock_init(&perf->db_lock);
+	perf_setup_mw(ntb, perf);
+	INIT_DELAYED_WORK(&perf->link_work, perf_link_work);
+	INIT_WORK(&perf->link_cleanup, perf_link_cleanup);
+
+	rc = ntb_set_ctx(ntb, perf, &perf_ops);
+	if (rc)
+		goto err_ctx;
+
+	perf->link_is_up = false;
+	ntb_link_enable(ntb, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
+	ntb_link_event(ntb);
+
+	rc = perf_debugfs_setup(perf);
+	if (rc)
+		goto err_ctx;
+
+	return 0;
+
+err_ctx:
+	cancel_delayed_work_sync(&perf->link_work);
+	cancel_work_sync(&perf->link_cleanup);
+	kfree(perf);
+err_perf:
+	return rc;
+}
+
+static void perf_remove(struct ntb_client *client, struct ntb_dev *ntb)
+{
+	struct perf_ctx *perf = ntb->ctx;
+	int i;
+
+	dev_dbg(&perf->ntb->dev, "%s called\n", __func__);
+
+	cancel_delayed_work_sync(&perf->link_work);
+	cancel_work_sync(&perf->link_cleanup);
+
+	ntb_clear_ctx(ntb);
+	ntb_link_disable(ntb);
+
+	debugfs_remove_recursive(perf_debugfs_dir);
+	perf_debugfs_dir = NULL;
+
+	if (use_dma) {
+		for (i = 0; i < MAX_THREADS; i++) {
+			struct pthr_ctx *pctx = &perf->pthr_ctx[i];
+
+			if (pctx->dma_chan)
+				dma_release_channel(pctx->dma_chan);
+		}
+	}
+
+	kfree(perf);
+}
+
+static struct ntb_client perf_client = {
+	.ops = {
+		.probe = perf_probe,
+		.remove = perf_remove,
+	},
+};
+module_ntb_client(perf_client);