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path: root/drivers/ntb/ntb_transport.c
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Diffstat (limited to 'drivers/ntb/ntb_transport.c')
-rw-r--r--drivers/ntb/ntb_transport.c1427
1 files changed, 1427 insertions, 0 deletions
diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
new file mode 100644
index 000000000000..c907e0773532
--- /dev/null
+++ b/drivers/ntb/ntb_transport.c
@@ -0,0 +1,1427 @@
+/*
+ * 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/dma-mapping.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/ntb.h>
+#include "ntb_hw.h"
+
+#define NTB_TRANSPORT_VERSION 1
+
+static int transport_mtu = 0x401E;
+module_param(transport_mtu, uint, 0644);
+MODULE_PARM_DESC(transport_mtu, "Maximum size of NTB transport packets");
+
+static unsigned char max_num_clients = 2;
+module_param(max_num_clients, byte, 0644);
+MODULE_PARM_DESC(max_num_clients, "Maximum number of NTB transport clients");
+
+struct ntb_queue_entry {
+ /* ntb_queue list reference */
+ struct list_head entry;
+ /* pointers to data to be transfered */
+ void *cb_data;
+ void *buf;
+ unsigned int len;
+ unsigned int flags;
+};
+
+struct ntb_transport_qp {
+ struct ntb_transport *transport;
+ struct ntb_device *ndev;
+ void *cb_data;
+
+ bool client_ready;
+ bool qp_link;
+ u8 qp_num; /* Only 64 QP's are allowed. 0-63 */
+
+ void (*tx_handler) (struct ntb_transport_qp *qp, void *qp_data,
+ void *data, int len);
+ struct list_head tx_free_q;
+ spinlock_t ntb_tx_free_q_lock;
+ void *tx_mw_begin;
+ void *tx_mw_end;
+ void *tx_offset;
+
+ void (*rx_handler) (struct ntb_transport_qp *qp, void *qp_data,
+ void *data, int len);
+ struct tasklet_struct rx_work;
+ struct list_head rx_pend_q;
+ struct list_head rx_free_q;
+ spinlock_t ntb_rx_pend_q_lock;
+ spinlock_t ntb_rx_free_q_lock;
+ void *rx_buff_begin;
+ void *rx_buff_end;
+ void *rx_offset;
+
+ void (*event_handler) (void *data, int status);
+ struct delayed_work link_work;
+
+ struct dentry *debugfs_dir;
+ struct dentry *debugfs_stats;
+
+ /* Stats */
+ u64 rx_bytes;
+ u64 rx_pkts;
+ u64 rx_ring_empty;
+ u64 rx_err_no_buf;
+ u64 rx_err_oflow;
+ u64 rx_err_ver;
+ u64 tx_bytes;
+ u64 tx_pkts;
+ u64 tx_ring_full;
+};
+
+struct ntb_transport_mw {
+ size_t size;
+ void *virt_addr;
+ dma_addr_t dma_addr;
+};
+
+struct ntb_transport_client_dev {
+ struct list_head entry;
+ struct device dev;
+};
+
+struct ntb_transport {
+ struct list_head entry;
+ struct list_head client_devs;
+
+ struct ntb_device *ndev;
+ struct ntb_transport_mw mw[NTB_NUM_MW];
+ struct ntb_transport_qp *qps;
+ unsigned int max_qps;
+ unsigned long qp_bitmap;
+ bool transport_link;
+ struct delayed_work link_work;
+ struct dentry *debugfs_dir;
+};
+
+enum {
+ DESC_DONE_FLAG = 1 << 0,
+ LINK_DOWN_FLAG = 1 << 1,
+};
+
+struct ntb_payload_header {
+ u64 ver;
+ unsigned int len;
+ unsigned int flags;
+};
+
+enum {
+ VERSION = 0,
+ MW0_SZ,
+ MW1_SZ,
+ NUM_QPS,
+ QP_LINKS,
+ MAX_SPAD,
+};
+
+#define QP_TO_MW(qp) ((qp) % NTB_NUM_MW)
+#define NTB_QP_DEF_NUM_ENTRIES 100
+#define NTB_LINK_DOWN_TIMEOUT 10
+
+static int ntb_match_bus(struct device *dev, struct device_driver *drv)
+{
+ return !strncmp(dev_name(dev), drv->name, strlen(drv->name));
+}
+
+static int ntb_client_probe(struct device *dev)
+{
+ const struct ntb_client *drv = container_of(dev->driver,
+ struct ntb_client, driver);
+ struct pci_dev *pdev = container_of(dev->parent, struct pci_dev, dev);
+ int rc = -EINVAL;
+
+ get_device(dev);
+ if (drv && drv->probe)
+ rc = drv->probe(pdev);
+ if (rc)
+ put_device(dev);
+
+ return rc;
+}
+
+static int ntb_client_remove(struct device *dev)
+{
+ const struct ntb_client *drv = container_of(dev->driver,
+ struct ntb_client, driver);
+ struct pci_dev *pdev = container_of(dev->parent, struct pci_dev, dev);
+
+ if (drv && drv->remove)
+ drv->remove(pdev);
+
+ put_device(dev);
+
+ return 0;
+}
+
+struct bus_type ntb_bus_type = {
+ .name = "ntb_bus",
+ .match = ntb_match_bus,
+ .probe = ntb_client_probe,
+ .remove = ntb_client_remove,
+};
+
+static LIST_HEAD(ntb_transport_list);
+
+static int __devinit ntb_bus_init(struct ntb_transport *nt)
+{
+ if (list_empty(&ntb_transport_list)) {
+ int rc = bus_register(&ntb_bus_type);
+ if (rc)
+ return rc;
+ }
+
+ list_add(&nt->entry, &ntb_transport_list);
+
+ return 0;
+}
+
+static void __devexit ntb_bus_remove(struct ntb_transport *nt)
+{
+ struct ntb_transport_client_dev *client_dev, *cd;
+
+ list_for_each_entry_safe(client_dev, cd, &nt->client_devs, entry) {
+ dev_err(client_dev->dev.parent, "%s still attached to bus, removing\n",
+ dev_name(&client_dev->dev));
+ list_del(&client_dev->entry);
+ device_unregister(&client_dev->dev);
+ }
+
+ list_del(&nt->entry);
+
+ if (list_empty(&ntb_transport_list))
+ bus_unregister(&ntb_bus_type);
+}
+
+static void ntb_client_release(struct device *dev)
+{
+ struct ntb_transport_client_dev *client_dev;
+ client_dev = container_of(dev, struct ntb_transport_client_dev, dev);
+
+ kfree(client_dev);
+}
+
+/**
+ * ntb_unregister_client_dev - Unregister NTB client device
+ * @device_name: Name of NTB client device
+ *
+ * Unregister an NTB client device with the NTB transport layer
+ */
+void ntb_unregister_client_dev(char *device_name)
+{
+ struct ntb_transport_client_dev *client, *cd;
+ struct ntb_transport *nt;
+
+ list_for_each_entry(nt, &ntb_transport_list, entry)
+ list_for_each_entry_safe(client, cd, &nt->client_devs, entry)
+ if (!strncmp(dev_name(&client->dev), device_name,
+ strlen(device_name))) {
+ list_del(&client->entry);
+ device_unregister(&client->dev);
+ }
+}
+EXPORT_SYMBOL_GPL(ntb_unregister_client_dev);
+
+/**
+ * ntb_register_client_dev - Register NTB client device
+ * @device_name: Name of NTB client device
+ *
+ * Register an NTB client device with the NTB transport layer
+ */
+int ntb_register_client_dev(char *device_name)
+{
+ struct ntb_transport_client_dev *client_dev;
+ struct ntb_transport *nt;
+ int rc;
+
+ list_for_each_entry(nt, &ntb_transport_list, entry) {
+ struct device *dev;
+
+ client_dev = kzalloc(sizeof(struct ntb_transport_client_dev),
+ GFP_KERNEL);
+ if (!client_dev) {
+ rc = -ENOMEM;
+ goto err;
+ }
+
+ dev = &client_dev->dev;
+
+ /* setup and register client devices */
+ dev_set_name(dev, "%s", device_name);
+ dev->bus = &ntb_bus_type;
+ dev->release = ntb_client_release;
+ dev->parent = &ntb_query_pdev(nt->ndev)->dev;
+
+ rc = device_register(dev);
+ if (rc) {
+ kfree(client_dev);
+ goto err;
+ }
+
+ list_add_tail(&client_dev->entry, &nt->client_devs);
+ }
+
+ return 0;
+
+err:
+ ntb_unregister_client_dev(device_name);
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(ntb_register_client_dev);
+
+/**
+ * ntb_register_client - Register NTB client driver
+ * @drv: NTB client driver to be registered
+ *
+ * Register an NTB client driver with the NTB transport layer
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_register_client(struct ntb_client *drv)
+{
+ drv->driver.bus = &ntb_bus_type;
+
+ return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(ntb_register_client);
+
+/**
+ * ntb_unregister_client - Unregister NTB client driver
+ * @drv: NTB client driver to be unregistered
+ *
+ * Unregister an NTB client driver with the NTB transport layer
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+void ntb_unregister_client(struct ntb_client *drv)
+{
+ driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(ntb_unregister_client);
+
+static int debugfs_open(struct inode *inode, struct file *filp)
+{
+ filp->private_data = inode->i_private;
+ return 0;
+}
+
+static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count,
+ loff_t *offp)
+{
+ struct ntb_transport_qp *qp;
+ char buf[1024];
+ ssize_t ret, out_offset, out_count;
+
+ out_count = 1024;
+
+ qp = filp->private_data;
+ out_offset = 0;
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "NTB QP stats\n");
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_bytes - \t%llu\n", qp->rx_bytes);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_pkts - \t%llu\n", qp->rx_pkts);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_ring_empty - %llu\n", qp->rx_ring_empty);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_err_no_buf - %llu\n", qp->rx_err_no_buf);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_err_oflow - \t%llu\n", qp->rx_err_oflow);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_err_ver - \t%llu\n", qp->rx_err_ver);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_buff_begin - %p\n", qp->rx_buff_begin);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_offset - \t%p\n", qp->rx_offset);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "rx_buff_end - \t%p\n", qp->rx_buff_end);
+
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "tx_bytes - \t%llu\n", qp->tx_bytes);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "tx_pkts - \t%llu\n", qp->tx_pkts);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "tx_ring_full - \t%llu\n", qp->tx_ring_full);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "tx_mw_begin - \t%p\n", qp->tx_mw_begin);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "tx_offset - \t%p\n", qp->tx_offset);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "tx_mw_end - \t%p\n", qp->tx_mw_end);
+
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "QP Link %s\n", (qp->qp_link == NTB_LINK_UP) ?
+ "Up" : "Down");
+
+ ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
+ return ret;
+}
+
+static const struct file_operations ntb_qp_debugfs_stats = {
+ .owner = THIS_MODULE,
+ .open = debugfs_open,
+ .read = debugfs_read,
+};
+
+static void ntb_list_add(spinlock_t *lock, struct list_head *entry,
+ struct list_head *list)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(lock, flags);
+ list_add_tail(entry, list);
+ spin_unlock_irqrestore(lock, flags);
+}
+
+static struct ntb_queue_entry *ntb_list_rm(spinlock_t *lock,
+ struct list_head *list)
+{
+ struct ntb_queue_entry *entry;
+ unsigned long flags;
+
+ spin_lock_irqsave(lock, flags);
+ if (list_empty(list)) {
+ entry = NULL;
+ goto out;
+ }
+ entry = list_first_entry(list, struct ntb_queue_entry, entry);
+ list_del(&entry->entry);
+out:
+ spin_unlock_irqrestore(lock, flags);
+
+ return entry;
+}
+
+static void ntb_transport_setup_qp_mw(struct ntb_transport *nt,
+ unsigned int qp_num)
+{
+ struct ntb_transport_qp *qp = &nt->qps[qp_num];
+ unsigned int size, num_qps_mw;
+ u8 mw_num = QP_TO_MW(qp_num);
+
+ WARN_ON(nt->mw[mw_num].virt_addr == 0);
+
+ if (nt->max_qps % NTB_NUM_MW && !mw_num)
+ num_qps_mw = nt->max_qps / NTB_NUM_MW +
+ (nt->max_qps % NTB_NUM_MW - mw_num);
+ else
+ num_qps_mw = nt->max_qps / NTB_NUM_MW;
+
+ size = nt->mw[mw_num].size / num_qps_mw;
+
+ qp->rx_buff_begin = nt->mw[mw_num].virt_addr +
+ (qp_num / NTB_NUM_MW * size);
+ qp->rx_buff_end = qp->rx_buff_begin + size;
+ qp->rx_offset = qp->rx_buff_begin;
+
+ qp->tx_mw_begin = ntb_get_mw_vbase(nt->ndev, mw_num) +
+ (qp_num / NTB_NUM_MW * size);
+ qp->tx_mw_end = qp->tx_mw_begin + size;
+ qp->tx_offset = qp->tx_mw_begin;
+
+ qp->rx_pkts = 0;
+ qp->tx_pkts = 0;
+}
+
+static int ntb_set_mw(struct ntb_transport *nt, int num_mw, unsigned int size)
+{
+ struct ntb_transport_mw *mw = &nt->mw[num_mw];
+ struct pci_dev *pdev = ntb_query_pdev(nt->ndev);
+ void *offset;
+
+ /* Alloc memory for receiving data. Must be 4k aligned */
+ mw->size = ALIGN(size, 4096);
+
+ mw->virt_addr = dma_alloc_coherent(&pdev->dev, mw->size, &mw->dma_addr,
+ GFP_KERNEL);
+ if (!mw->virt_addr) {
+ dev_err(&pdev->dev, "Unable to allocate MW buffer of size %d\n",
+ (int) mw->size);
+ return -ENOMEM;
+ }
+
+ /* setup the hdr offsets with 0's */
+ for (offset = mw->virt_addr + transport_mtu -
+ sizeof(struct ntb_payload_header);
+ offset < mw->virt_addr + size; offset += transport_mtu)
+ memset(offset, 0, sizeof(struct ntb_payload_header));
+
+ /* Notify HW the memory location of the receive buffer */
+ ntb_set_mw_addr(nt->ndev, num_mw, mw->dma_addr);
+
+ return 0;
+}
+
+static void ntb_qp_link_down(struct ntb_transport_qp *qp)
+{
+ struct ntb_transport *nt = qp->transport;
+ struct pci_dev *pdev = ntb_query_pdev(nt->ndev);
+
+ if (qp->qp_link == NTB_LINK_DOWN) {
+ cancel_delayed_work_sync(&qp->link_work);
+ return;
+ }
+
+ if (qp->event_handler)
+ qp->event_handler(qp->cb_data, NTB_LINK_DOWN);
+
+ dev_info(&pdev->dev, "qp %d: Link Down\n", qp->qp_num);
+ qp->qp_link = NTB_LINK_DOWN;
+
+ if (nt->transport_link == NTB_LINK_UP)
+ schedule_delayed_work(&qp->link_work,
+ msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
+}
+
+static void ntb_transport_conn_down(struct ntb_transport *nt)
+{
+ int i;
+
+ if (nt->transport_link == NTB_LINK_DOWN)
+ cancel_delayed_work_sync(&nt->link_work);
+ else
+ nt->transport_link = NTB_LINK_DOWN;
+
+ /* Pass along the info to any clients */
+ for (i = 0; i < nt->max_qps; i++)
+ if (!test_bit(i, &nt->qp_bitmap))
+ ntb_qp_link_down(&nt->qps[i]);
+
+ /* The scratchpad registers keep the values if the remote side
+ * goes down, blast them now to give them a sane value the next
+ * time they are accessed
+ */
+ for (i = 0; i < MAX_SPAD; i++)
+ ntb_write_local_spad(nt->ndev, i, 0);
+}
+
+static void ntb_transport_event_callback(void *data, enum ntb_hw_event event)
+{
+ struct ntb_transport *nt = data;
+
+ switch (event) {
+ case NTB_EVENT_HW_LINK_UP:
+ schedule_delayed_work(&nt->link_work, 0);
+ break;
+ case NTB_EVENT_HW_LINK_DOWN:
+ ntb_transport_conn_down(nt);
+ break;
+ default:
+ BUG();
+ }
+}
+
+static void ntb_transport_link_work(struct work_struct *work)
+{
+ struct ntb_transport *nt = container_of(work, struct ntb_transport,
+ link_work.work);
+ struct ntb_device *ndev = nt->ndev;
+ struct pci_dev *pdev = ntb_query_pdev(ndev);
+ u32 val;
+ int rc, i;
+
+ /* send the local info */
+ rc = ntb_write_remote_spad(ndev, VERSION, NTB_TRANSPORT_VERSION);
+ if (rc) {
+ dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
+ 0, VERSION);
+ goto out;
+ }
+
+ rc = ntb_write_remote_spad(ndev, MW0_SZ, ntb_get_mw_size(ndev, 0));
+ if (rc) {
+ dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
+ (u32) ntb_get_mw_size(ndev, 0), MW0_SZ);
+ goto out;
+ }
+
+ rc = ntb_write_remote_spad(ndev, MW1_SZ, ntb_get_mw_size(ndev, 1));
+ if (rc) {
+ dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
+ (u32) ntb_get_mw_size(ndev, 1), MW1_SZ);
+ goto out;
+ }
+
+ rc = ntb_write_remote_spad(ndev, NUM_QPS, nt->max_qps);
+ if (rc) {
+ dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
+ nt->max_qps, NUM_QPS);
+ goto out;
+ }
+
+ rc = ntb_read_local_spad(nt->ndev, QP_LINKS, &val);
+ if (rc) {
+ dev_err(&pdev->dev, "Error reading spad %d\n", QP_LINKS);
+ goto out;
+ }
+
+ rc = ntb_write_remote_spad(ndev, QP_LINKS, val);
+ if (rc) {
+ dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
+ val, QP_LINKS);
+ goto out;
+ }
+
+ /* Query the remote side for its info */
+ rc = ntb_read_remote_spad(ndev, VERSION, &val);
+ if (rc) {
+ dev_err(&pdev->dev, "Error reading remote spad %d\n", VERSION);
+ goto out;
+ }
+
+ if (val != NTB_TRANSPORT_VERSION)
+ goto out;
+ dev_dbg(&pdev->dev, "Remote version = %d\n", val);
+
+ rc = ntb_read_remote_spad(ndev, NUM_QPS, &val);
+ if (rc) {
+ dev_err(&pdev->dev, "Error reading remote spad %d\n", NUM_QPS);
+ goto out;
+ }
+
+ if (val != nt->max_qps)
+ goto out;
+ dev_dbg(&pdev->dev, "Remote max number of qps = %d\n", val);
+
+ rc = ntb_read_remote_spad(ndev, MW0_SZ, &val);
+ if (rc) {
+ dev_err(&pdev->dev, "Error reading remote spad %d\n", MW0_SZ);
+ goto out;
+ }
+
+ if (!val)
+ goto out;
+ dev_dbg(&pdev->dev, "Remote MW0 size = %d\n", val);
+
+ rc = ntb_set_mw(nt, 0, val);
+ if (rc)
+ goto out;
+
+ rc = ntb_read_remote_spad(ndev, MW1_SZ, &val);
+ if (rc) {
+ dev_err(&pdev->dev, "Error reading remote spad %d\n", MW1_SZ);
+ goto out;
+ }
+
+ if (!val)
+ goto out;
+ dev_dbg(&pdev->dev, "Remote MW1 size = %d\n", val);
+
+ rc = ntb_set_mw(nt, 1, val);
+ if (rc)
+ goto out;
+
+ nt->transport_link = NTB_LINK_UP;
+
+ for (i = 0; i < nt->max_qps; i++) {
+ struct ntb_transport_qp *qp = &nt->qps[i];
+
+ ntb_transport_setup_qp_mw(nt, i);
+
+ if (qp->client_ready == NTB_LINK_UP)
+ schedule_delayed_work(&qp->link_work, 0);
+ }
+
+ return;
+
+out:
+ if (ntb_hw_link_status(ndev))
+ schedule_delayed_work(&nt->link_work,
+ msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
+}
+
+static void ntb_qp_link_work(struct work_struct *work)
+{
+ struct ntb_transport_qp *qp = container_of(work,
+ struct ntb_transport_qp,
+ link_work.work);
+ struct pci_dev *pdev = ntb_query_pdev(qp->ndev);
+ struct ntb_transport *nt = qp->transport;
+ int rc, val;
+
+ WARN_ON(nt->transport_link != NTB_LINK_UP);
+
+ rc = ntb_read_local_spad(nt->ndev, QP_LINKS, &val);
+ if (rc) {
+ dev_err(&pdev->dev, "Error reading spad %d\n", QP_LINKS);
+ return;
+ }
+
+ rc = ntb_write_remote_spad(nt->ndev, QP_LINKS, val | 1 << qp->qp_num);
+ if (rc)
+ dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
+ val | 1 << qp->qp_num, QP_LINKS);
+
+ /* query remote spad for qp ready bits */
+ rc = ntb_read_remote_spad(nt->ndev, QP_LINKS, &val);
+ if (rc)
+ dev_err(&pdev->dev, "Error reading remote spad %d\n", QP_LINKS);
+
+ dev_dbg(&pdev->dev, "Remote QP link status = %x\n", val);
+
+ /* See if the remote side is up */
+ if (1 << qp->qp_num & val) {
+ qp->qp_link = NTB_LINK_UP;
+
+ dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
+ if (qp->event_handler)
+ qp->event_handler(qp->cb_data, NTB_LINK_UP);
+ } else if (nt->transport_link == NTB_LINK_UP)
+ schedule_delayed_work(&qp->link_work,
+ msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
+}
+
+static void ntb_transport_init_queue(struct ntb_transport *nt,
+ unsigned int qp_num)
+{
+ struct ntb_transport_qp *qp;
+
+ qp = &nt->qps[qp_num];
+ qp->qp_num = qp_num;
+ qp->transport = nt;
+ qp->ndev = nt->ndev;
+ qp->qp_link = NTB_LINK_DOWN;
+ qp->client_ready = NTB_LINK_DOWN;
+ qp->event_handler = NULL;
+
+ if (nt->debugfs_dir) {
+ char debugfs_name[4];
+
+ snprintf(debugfs_name, 4, "qp%d", qp_num);
+ qp->debugfs_dir = debugfs_create_dir(debugfs_name,
+ nt->debugfs_dir);
+
+ qp->debugfs_stats = debugfs_create_file("stats", S_IRUSR,
+ qp->debugfs_dir, qp,
+ &ntb_qp_debugfs_stats);
+ }
+
+ INIT_DELAYED_WORK(&qp->link_work, ntb_qp_link_work);
+
+ spin_lock_init(&qp->ntb_rx_pend_q_lock);
+ spin_lock_init(&qp->ntb_rx_free_q_lock);
+ spin_lock_init(&qp->ntb_tx_free_q_lock);
+
+ INIT_LIST_HEAD(&qp->rx_pend_q);
+ INIT_LIST_HEAD(&qp->rx_free_q);
+ INIT_LIST_HEAD(&qp->tx_free_q);
+}
+
+int ntb_transport_init(struct pci_dev *pdev)
+{
+ struct ntb_transport *nt;
+ int rc, i;
+
+ nt = kzalloc(sizeof(struct ntb_transport), GFP_KERNEL);
+ if (!nt)
+ return -ENOMEM;
+
+ if (debugfs_initialized())
+ nt->debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
+ else
+ nt->debugfs_dir = NULL;
+
+ nt->ndev = ntb_register_transport(pdev, nt);
+ if (!nt->ndev) {
+ rc = -EIO;
+ goto err;
+ }
+
+ nt->max_qps = min(nt->ndev->max_cbs, max_num_clients);
+
+ nt->qps = kcalloc(nt->max_qps, sizeof(struct ntb_transport_qp),
+ GFP_KERNEL);
+ if (!nt->qps) {
+ rc = -ENOMEM;
+ goto err1;
+ }
+
+ nt->qp_bitmap = ((u64) 1 << nt->max_qps) - 1;
+
+ for (i = 0; i < nt->max_qps; i++)
+ ntb_transport_init_queue(nt, i);
+
+ INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work);
+
+ rc = ntb_register_event_callback(nt->ndev,
+ ntb_transport_event_callback);
+ if (rc)
+ goto err2;
+
+ INIT_LIST_HEAD(&nt->client_devs);
+ rc = ntb_bus_init(nt);
+ if (rc)
+ goto err3;
+
+ if (ntb_hw_link_status(nt->ndev))
+ schedule_delayed_work(&nt->link_work, 0);
+
+ return 0;
+
+err3:
+ ntb_unregister_event_callback(nt->ndev);
+err2:
+ kfree(nt->qps);
+err1:
+ ntb_unregister_transport(nt->ndev);
+err:
+ debugfs_remove_recursive(nt->debugfs_dir);
+ kfree(nt);
+ return rc;
+}
+
+void ntb_transport_free(void *transport)
+{
+ struct ntb_transport *nt = transport;
+ struct pci_dev *pdev;
+ int i;
+
+ nt->transport_link = NTB_LINK_DOWN;
+
+ /* verify that all the qp's are freed */
+ for (i = 0; i < nt->max_qps; i++)
+ if (!test_bit(i, &nt->qp_bitmap))
+ ntb_transport_free_queue(&nt->qps[i]);
+
+ ntb_bus_remove(nt);
+
+ cancel_delayed_work_sync(&nt->link_work);
+
+ debugfs_remove_recursive(nt->debugfs_dir);
+
+ ntb_unregister_event_callback(nt->ndev);
+
+ pdev = ntb_query_pdev(nt->ndev);
+
+ for (i = 0; i < NTB_NUM_MW; i++)
+ if (nt->mw[i].virt_addr)
+ dma_free_coherent(&pdev->dev, nt->mw[i].size,
+ nt->mw[i].virt_addr,
+ nt->mw[i].dma_addr);
+
+ kfree(nt->qps);
+ ntb_unregister_transport(nt->ndev);
+ kfree(nt);
+}
+
+static void ntb_rx_copy_task(struct ntb_transport_qp *qp,
+ struct ntb_queue_entry *entry, void *offset)
+{
+
+ struct ntb_payload_header *hdr;
+
+ BUG_ON(offset < qp->rx_buff_begin ||
+ offset + transport_mtu >= qp->rx_buff_end);
+
+ hdr = offset + transport_mtu - sizeof(struct ntb_payload_header);
+ entry->len = hdr->len;
+
+ memcpy(entry->buf, offset, entry->len);
+
+ /* Ensure that the data is fully copied out before clearing the flag */
+ wmb();
+ hdr->flags = 0;
+
+ if (qp->rx_handler && qp->client_ready == NTB_LINK_UP)
+ qp->rx_handler(qp, qp->cb_data, entry->cb_data, entry->len);
+
+ ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry, &qp->rx_free_q);
+}
+
+static int ntb_process_rxc(struct ntb_transport_qp *qp)
+{
+ struct ntb_payload_header *hdr;
+ struct ntb_queue_entry *entry;
+ void *offset;
+
+ entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
+ if (!entry) {
+ hdr = offset + transport_mtu -
+ sizeof(struct ntb_payload_header);
+ dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
+ "no buffer - HDR ver %llu, len %d, flags %x\n",
+ hdr->ver, hdr->len, hdr->flags);
+ qp->rx_err_no_buf++;
+ return -ENOMEM;
+ }
+
+ offset = qp->rx_offset;
+ hdr = offset + transport_mtu - sizeof(struct ntb_payload_header);
+
+ if (!(hdr->flags & DESC_DONE_FLAG)) {
+ ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
+ &qp->rx_pend_q);
+ qp->rx_ring_empty++;
+ return -EAGAIN;
+ }
+
+ if (hdr->ver != qp->rx_pkts) {
+ dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
+ "qp %d: version mismatch, expected %llu - got %llu\n",
+ qp->qp_num, qp->rx_pkts, hdr->ver);
+ ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
+ &qp->rx_pend_q);
+ qp->rx_err_ver++;
+ return -EIO;
+ }
+
+ if (hdr->flags & LINK_DOWN_FLAG) {
+ ntb_qp_link_down(qp);
+
+ ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
+ &qp->rx_pend_q);
+
+ /* Ensure that the data is fully copied out before clearing the
+ * done flag
+ */
+ wmb();
+ hdr->flags = 0;
+ goto out;
+ }
+
+ dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
+ "rx offset %p, ver %llu - %d payload received, buf size %d\n",
+ qp->rx_offset, hdr->ver, hdr->len, entry->len);
+
+ if (hdr->len <= entry->len)
+ ntb_rx_copy_task(qp, entry, offset);
+ else {
+ ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
+ &qp->rx_pend_q);
+
+ /* Ensure that the data is fully copied out before clearing the
+ * done flag
+ */
+ wmb();
+ hdr->flags = 0;
+ qp->rx_err_oflow++;
+ dev_dbg(&ntb_query_pdev(qp->ndev)->dev,
+ "RX overflow! Wanted %d got %d\n",
+ hdr->len, entry->len);
+ }
+
+ qp->rx_bytes += hdr->len;
+ qp->rx_pkts++;
+
+out:
+ qp->rx_offset += transport_mtu;
+ if (qp->rx_offset + transport_mtu >= qp->rx_buff_end)
+ qp->rx_offset = qp->rx_buff_begin;
+
+ return 0;
+}
+
+static void ntb_transport_rx(unsigned long data)
+{
+ struct ntb_transport_qp *qp = (struct ntb_transport_qp *)data;
+ int rc;
+
+ do {
+ rc = ntb_process_rxc(qp);
+ } while (!rc);
+}
+
+static void ntb_transport_rxc_db(void *data, int db_num)
+{
+ struct ntb_transport_qp *qp = data;
+
+ dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "%s: doorbell %d received\n",
+ __func__, db_num);
+
+ tasklet_schedule(&qp->rx_work);
+}
+
+static void ntb_tx_copy_task(struct ntb_transport_qp *qp,
+ struct ntb_queue_entry *entry,
+ void *offset)
+{
+ struct ntb_payload_header *hdr;
+
+ BUG_ON(offset < qp->tx_mw_begin ||
+ offset + transport_mtu >= qp->tx_mw_end);
+
+ memcpy_toio(offset, entry->buf, entry->len);
+
+ hdr = offset + transport_mtu - sizeof(struct ntb_payload_header);
+ hdr->len = entry->len;
+ hdr->ver = qp->tx_pkts;
+
+ /* Ensure that the data is fully copied out before setting the flag */
+ mmiowb();
+ hdr->flags = entry->flags | DESC_DONE_FLAG;
+
+ ntb_ring_sdb(qp->ndev, qp->qp_num);
+
+ /* The entry length can only be zero if the packet is intended to be a
+ * "link down" or similar. Since no payload is being sent in these
+ * cases, there is nothing to add to the completion queue.
+ */
+ if (entry->len > 0) {
+ qp->tx_bytes += entry->len;
+
+ if (qp->tx_handler)
+ qp->tx_handler(qp, qp->cb_data, entry->cb_data,
+ entry->len);
+ }
+
+ ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q);
+}
+
+static int ntb_process_tx(struct ntb_transport_qp *qp,
+ struct ntb_queue_entry *entry)
+{
+ struct ntb_payload_header *hdr;
+ void *offset;
+
+ offset = qp->tx_offset;
+ hdr = offset + transport_mtu - sizeof(struct ntb_payload_header);
+
+ dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "%lld - offset %p, tx %p, entry len %d flags %x buff %p\n",
+ qp->tx_pkts, offset, qp->tx_offset, entry->len, entry->flags,
+ entry->buf);
+ if (hdr->flags) {
+ qp->tx_ring_full++;
+ return -EAGAIN;
+ }
+
+ if (entry->len > transport_mtu - sizeof(struct ntb_payload_header)) {
+ if (qp->tx_handler)
+ qp->tx_handler(qp->cb_data, qp, NULL, -EIO);
+
+ ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
+ &qp->tx_free_q);
+ return 0;
+ }
+
+ ntb_tx_copy_task(qp, entry, offset);
+
+ qp->tx_offset += transport_mtu;
+ if (qp->tx_offset + transport_mtu >= qp->tx_mw_end)
+ qp->tx_offset = qp->tx_mw_begin;
+
+ qp->tx_pkts++;
+
+ return 0;
+}
+
+static void ntb_send_link_down(struct ntb_transport_qp *qp)
+{
+ struct pci_dev *pdev = ntb_query_pdev(qp->ndev);
+ struct ntb_queue_entry *entry;
+ int i, rc;
+
+ if (qp->qp_link == NTB_LINK_DOWN)
+ return;
+
+ qp->qp_link = NTB_LINK_DOWN;
+ dev_info(&pdev->dev, "qp %d: Link Down\n", qp->qp_num);
+
+ for (i = 0; i < NTB_LINK_DOWN_TIMEOUT; i++) {
+ entry = ntb_list_rm(&qp->ntb_tx_free_q_lock,
+ &qp->tx_free_q);
+ if (entry)
+ break;
+ msleep(100);
+ }
+
+ if (!entry)
+ return;
+
+ entry->cb_data = NULL;
+ entry->buf = NULL;
+ entry->len = 0;
+ entry->flags = LINK_DOWN_FLAG;
+
+ rc = ntb_process_tx(qp, entry);
+ if (rc)
+ dev_err(&pdev->dev, "ntb: QP%d unable to send linkdown msg\n",
+ qp->qp_num);
+}
+
+/**
+ * ntb_transport_create_queue - Create a new NTB transport layer queue
+ * @rx_handler: receive callback function
+ * @tx_handler: transmit callback function
+ * @event_handler: event callback function
+ *
+ * Create a new NTB transport layer queue and provide the queue with a callback
+ * routine for both transmit and receive. The receive callback routine will be
+ * used to pass up data when the transport has received it on the queue. The
+ * transmit callback routine will be called when the transport has completed the
+ * transmission of the data on the queue and the data is ready to be freed.
+ *
+ * RETURNS: pointer to newly created ntb_queue, NULL on error.
+ */
+struct ntb_transport_qp *
+ntb_transport_create_queue(void *data, struct pci_dev *pdev,
+ const struct ntb_queue_handlers *handlers)
+{
+ struct ntb_queue_entry *entry;
+ struct ntb_transport_qp *qp;
+ struct ntb_transport *nt;
+ unsigned int free_queue;
+ int rc, i;
+
+ nt = ntb_find_transport(pdev);
+ if (!nt)
+ goto err;
+
+ free_queue = ffs(nt->qp_bitmap);
+ if (!free_queue)
+ goto err;
+
+ /* decrement free_queue to make it zero based */
+ free_queue--;
+
+ clear_bit(free_queue, &nt->qp_bitmap);
+
+ qp = &nt->qps[free_queue];
+ qp->cb_data = data;
+ qp->rx_handler = handlers->rx_handler;
+ qp->tx_handler = handlers->tx_handler;
+ qp->event_handler = handlers->event_handler;
+
+ for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
+ entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC);
+ if (!entry)
+ goto err1;
+
+ ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry,
+ &qp->rx_free_q);
+ }
+
+ for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
+ entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC);
+ if (!entry)
+ goto err2;
+
+ ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
+ &qp->tx_free_q);
+ }
+
+ tasklet_init(&qp->rx_work, ntb_transport_rx, (unsigned long) qp);
+
+ rc = ntb_register_db_callback(qp->ndev, free_queue, qp,
+ ntb_transport_rxc_db);
+ if (rc)
+ goto err3;
+
+ dev_info(&pdev->dev, "NTB Transport QP %d created\n", qp->qp_num);
+
+ return qp;
+
+err3:
+ tasklet_disable(&qp->rx_work);
+err2:
+ while ((entry =
+ ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
+ kfree(entry);
+err1:
+ while ((entry =
+ ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
+ kfree(entry);
+ set_bit(free_queue, &nt->qp_bitmap);
+err:
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_create_queue);
+
+/**
+ * ntb_transport_free_queue - Frees NTB transport queue
+ * @qp: NTB queue to be freed
+ *
+ * Frees NTB transport queue
+ */
+void ntb_transport_free_queue(struct ntb_transport_qp *qp)
+{
+ struct pci_dev *pdev = ntb_query_pdev(qp->ndev);
+ struct ntb_queue_entry *entry;
+
+ if (!qp)
+ return;
+
+ cancel_delayed_work_sync(&qp->link_work);
+
+ ntb_unregister_db_callback(qp->ndev, qp->qp_num);
+ tasklet_disable(&qp->rx_work);
+
+ while ((entry =
+ ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
+ kfree(entry);
+
+ while ((entry =
+ ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q))) {
+ dev_warn(&pdev->dev, "Freeing item from a non-empty queue\n");
+ kfree(entry);
+ }
+
+ while ((entry =
+ ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q)))
+ kfree(entry);
+
+ set_bit(qp->qp_num, &qp->transport->qp_bitmap);
+
+ dev_info(&pdev->dev, "NTB Transport QP %d freed\n", qp->qp_num);
+}
+EXPORT_SYMBOL_GPL(ntb_transport_free_queue);
+
+/**
+ * ntb_transport_rx_remove - Dequeues enqueued rx packet
+ * @qp: NTB queue to be freed
+ * @len: pointer to variable to write enqueued buffers length
+ *
+ * Dequeues unused buffers from receive queue. Should only be used during
+ * shutdown of qp.
+ *
+ * RETURNS: NULL error value on error, or void* for success.
+ */
+void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len)
+{
+ struct ntb_queue_entry *entry;
+ void *buf;
+
+ if (!qp || qp->client_ready == NTB_LINK_UP)
+ return NULL;
+
+ entry = ntb_list_rm(&qp->ntb_rx_pend_q_lock, &qp->rx_pend_q);
+ if (!entry)
+ return NULL;
+
+ buf = entry->cb_data;
+ *len = entry->len;
+
+ ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry,
+ &qp->rx_free_q);
+
+ return buf;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_rx_remove);
+
+/**
+ * ntb_transport_rx_enqueue - Enqueue a new NTB queue entry
+ * @qp: NTB transport layer queue the entry is to be enqueued on
+ * @cb: per buffer pointer for callback function to use
+ * @data: pointer to data buffer that incoming packets will be copied into
+ * @len: length of the data buffer
+ *
+ * Enqueue a new receive buffer onto the transport queue into which a NTB
+ * payload can be received into.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
+ unsigned int len)
+{
+ struct ntb_queue_entry *entry;
+
+ if (!qp)
+ return -EINVAL;
+
+ entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q);
+ if (!entry)
+ return -ENOMEM;
+
+ entry->cb_data = cb;
+ entry->buf = data;
+ entry->len = len;
+
+ ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry,
+ &qp->rx_pend_q);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
+
+/**
+ * ntb_transport_tx_enqueue - Enqueue a new NTB queue entry
+ * @qp: NTB transport layer queue the entry is to be enqueued on
+ * @cb: per buffer pointer for callback function to use
+ * @data: pointer to data buffer that will be sent
+ * @len: length of the data buffer
+ *
+ * Enqueue a new transmit buffer onto the transport queue from which a NTB
+ * payload will be transmitted. This assumes that a lock is behing held to
+ * serialize access to the qp.
+ *
+ * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
+ */
+int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
+ unsigned int len)
+{
+ struct ntb_queue_entry *entry;
+ int rc;
+
+ if (!qp || qp->qp_link != NTB_LINK_UP || !len)
+ return -EINVAL;
+
+ entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
+ if (!entry)
+ return -ENOMEM;
+
+ entry->cb_data = cb;
+ entry->buf = data;
+ entry->len = len;
+ entry->flags = 0;
+
+ rc = ntb_process_tx(qp, entry);
+ if (rc)
+ ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry,
+ &qp->tx_free_q);
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_tx_enqueue);
+
+/**
+ * ntb_transport_link_up - Notify NTB transport of client readiness to use queue
+ * @qp: NTB transport layer queue to be enabled
+ *
+ * Notify NTB transport layer of client readiness to use queue
+ */
+void ntb_transport_link_up(struct ntb_transport_qp *qp)
+{
+ if (!qp)
+ return;
+
+ qp->client_ready = NTB_LINK_UP;
+
+ if (qp->transport->transport_link == NTB_LINK_UP)
+ schedule_delayed_work(&qp->link_work, 0);
+}
+EXPORT_SYMBOL_GPL(ntb_transport_link_up);
+
+/**
+ * ntb_transport_link_down - Notify NTB transport to no longer enqueue data
+ * @qp: NTB transport layer queue to be disabled
+ *
+ * Notify NTB transport layer of client's desire to no longer receive data on
+ * transport queue specified. It is the client's responsibility to ensure all
+ * entries on queue are purged or otherwise handled appropraitely.
+ */
+void ntb_transport_link_down(struct ntb_transport_qp *qp)
+{
+ struct pci_dev *pdev = ntb_query_pdev(qp->ndev);
+ int rc, val;
+
+ if (!qp)
+ return;
+
+ qp->client_ready = NTB_LINK_DOWN;
+
+ rc = ntb_read_local_spad(qp->ndev, QP_LINKS, &val);
+ if (rc) {
+ dev_err(&pdev->dev, "Error reading spad %d\n", QP_LINKS);
+ return;
+ }
+
+ rc = ntb_write_remote_spad(qp->ndev, QP_LINKS,
+ val & ~(1 << qp->qp_num));
+ if (rc)
+ dev_err(&pdev->dev, "Error writing %x to remote spad %d\n",
+ val & ~(1 << qp->qp_num), QP_LINKS);
+
+ if (qp->qp_link == NTB_LINK_UP)
+ ntb_send_link_down(qp);
+ else
+ cancel_delayed_work_sync(&qp->link_work);
+}
+EXPORT_SYMBOL_GPL(ntb_transport_link_down);
+
+/**
+ * ntb_transport_link_query - Query transport link state
+ * @qp: NTB transport layer queue to be queried
+ *
+ * Query connectivity to the remote system of the NTB transport queue
+ *
+ * RETURNS: true for link up or false for link down
+ */
+bool ntb_transport_link_query(struct ntb_transport_qp *qp)
+{
+ return qp->qp_link == NTB_LINK_UP;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_link_query);
+
+/**
+ * ntb_transport_qp_num - Query the qp number
+ * @qp: NTB transport layer queue to be queried
+ *
+ * Query qp number of the NTB transport queue
+ *
+ * RETURNS: a zero based number specifying the qp number
+ */
+unsigned char ntb_transport_qp_num(struct ntb_transport_qp *qp)
+{
+ return qp->qp_num;
+}
+EXPORT_SYMBOL_GPL(ntb_transport_qp_num);
+
+/**
+ * ntb_transport_max_size - Query the max payload size of a qp
+ * @qp: NTB transport layer queue to be queried
+ *
+ * Query the maximum payload size permissible on the given qp
+ *
+ * RETURNS: the max payload size of a qp
+ */
+unsigned int
+ntb_transport_max_size(__attribute__((unused)) struct ntb_transport_qp *qp)
+{
+ return transport_mtu - sizeof(struct ntb_payload_header);
+}
+EXPORT_SYMBOL_GPL(ntb_transport_max_size);