--- /dev/null
+/*
+ * 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);