[PATCH v4 02/19] NTB: Add NTB hardware abstraction layer

[Allen Hubbe]

Abstract the NTB device behind a programming interface, so that it can
support different hardware and client drivers.

Signed-off-by: Allen Hubbe <Allen.Hubbe@xxxxxxx>
---

This was split from the larger patch in v1..v3.  This is the first part
of the split.

The new NTB api is added in this patch, without the noise of changing
the existing drivers to use it.  After applying this patch, the new NTB
API exists, but the existing hardware and client drivers do not use it.
The next patch changes hardware and client drivers.

 Documentation/ntb.txt |  32 ++
 MAINTAINERS           |   5 +-
 drivers/ntb/Makefile  |   1 +
 drivers/ntb/ntb.c     | 251 +++++++++++++
 include/linux/ntb.h   | 984 ++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 1272 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/ntb.txt
 create mode 100644 drivers/ntb/ntb.c
 create mode 100644 include/linux/ntb.h

diff --git a/Documentation/ntb.txt b/Documentation/ntb.txt
new file mode 100644
index 000000000000..9d46dc9712a8
--- /dev/null
+++ b/Documentation/ntb.txt
@@ -0,0 +1,32 @@
+# NTB Drivers
+
+NTB (Non-Transparent Bridge) is a type of PCI-Express bridge chip that connects
+the separate memory systems of two computers to the same PCI-Express fabric.
+Existing NTB hardware supports a common feature set, including scratchpad
+registers, doorbell registers, and memory translation windows.  Scratchpad
+registers are read-and-writable registers that are accessible from either side
+of the device, so that peers can exchange a small amount of information at a
+fixed address.  Doorbell registers provide a way for peers to send interrupt
+events.  Memory windows allow translated read and write access to the peer
+memory.
+
+## NTB Core Driver (ntb)
+
+The NTB core driver defines an api wrapping the common feature set, and allows
+clients interested in NTB features to discover NTB the devices supported by
+hardware drivers.  The term "client" is used here to mean an upper layer
+component making use of the NTB api.  The term "driver," or "hardware driver,"
+is used here to mean a driver for a specific vendor and model of NTB hardware.
+
+## NTB Client Drivers
+
+NTB client drivers should register with the NTB core driver.  After
+registering, the client probe and remove functions will be called appropriately
+as ntb hardware, or hardware drivers, are inserted and removed.  The
+registration uses the Linux Device framework, so it should feel familiar to
+anyone who has written a pci driver.
+
+## NTB Hardware Drivers
+
+NTB hardware drivers should register devices with the NTB core driver.  After
+registering, clients probe and remove functions will be called.
diff --git a/MAINTAINERS b/MAINTAINERS
index a5b8584da5bf..2e351265d544 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6978,7 +6978,7 @@ F:	drivers/power/bq27x00_battery.c
 F:	drivers/power/isp1704_charger.c
 F:	drivers/power/rx51_battery.c
 
-NTB DRIVER
+NTB DRIVER CORE
 M:	Jon Mason <jdmason@xxxxxxxx>
 M:	Dave Jiang <dave.jiang@xxxxxxxxx>
 S:	Supported
@@ -6986,7 +6986,10 @@ W:	https://github.com/jonmason/ntb/wiki
 T:	git git://github.com/jonmason/ntb.git
 F:	drivers/ntb/
 F:	drivers/net/ntb_netdev.c
+F:	drivers/ntb/ntb.c
+F:	drivers/ntb/ntb_transport.c
 F:	include/linux/ntb.h
+F:	include/linux/ntb_transport.h
 
 NTFS FILESYSTEM
 M:	Anton Altaparmakov <anton@xxxxxxxxxx>
diff --git a/drivers/ntb/Makefile b/drivers/ntb/Makefile
index 545b10a131af..712e953a8fda 100644
--- a/drivers/ntb/Makefile
+++ b/drivers/ntb/Makefile
@@ -1,3 +1,4 @@
+obj-$(CONFIG_NTB) += ntb.o
 obj-$(CONFIG_NTB) += ntb_hw_intel.o
 
 ntb_hw_intel-objs := hw/intel/ntb_hw_intel.o ntb_transport.o
diff --git a/drivers/ntb/ntb.c b/drivers/ntb/ntb.c
new file mode 100644
index 000000000000..23435f2a5486
--- /dev/null
+++ b/drivers/ntb/ntb.c
@@ -0,0 +1,251 @@
+/*
+ * 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 EMC 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.
+ *
+ *   This program is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *   General Public License for more details.
+ *
+ *   BSD LICENSE
+ *
+ *   Copyright (C) 2015 EMC 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 Linux driver
+ *
+ * Contact Information:
+ * Allen Hubbe <Allen.Hubbe@xxxxxxx>
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#include <linux/ntb.h>
+#include <linux/pci.h>
+
+#define DRIVER_NAME			"ntb"
+#define DRIVER_DESCRIPTION		"PCIe NTB Driver Framework"
+
+#define DRIVER_LICENSE			"Dual BSD/GPL"
+#define DRIVER_VERSION			"1.0"
+#define DRIVER_RELDATE			"24 March 2015"
+#define DRIVER_AUTHOR			"Allen Hubbe <Allen.Hubbe@xxxxxxx>"
+
+MODULE_LICENSE(DRIVER_LICENSE);
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESCRIPTION);
+
+static struct bus_type ntb_bus;
+static void ntb_dev_release(struct device *dev);
+
+int __ntb_register_client(struct ntb_client *client, struct module *mod,
+			  const char *mod_name)
+{
+	if (!client)
+		return -EINVAL;
+	if (!ntb_client_ops_is_valid(&client->ops))
+		return -EINVAL;
+
+	memset(&client->drv, 0, sizeof(client->drv));
+	client->drv.bus = &ntb_bus;
+	client->drv.name = mod_name;
+	client->drv.owner = mod;
+
+	return driver_register(&client->drv);
+}
+EXPORT_SYMBOL(__ntb_register_client);
+
+void ntb_unregister_client(struct ntb_client *client)
+{
+	driver_unregister(&client->drv);
+}
+EXPORT_SYMBOL(ntb_unregister_client);
+
+int ntb_register_device(struct ntb_dev *ntb)
+{
+	if (!ntb)
+		return -EINVAL;
+	if (!ntb->pdev)
+		return -EINVAL;
+	if (!ntb->ops)
+		return -EINVAL;
+	if (!ntb_dev_ops_is_valid(ntb->ops))
+		return -EINVAL;
+
+	init_completion(&ntb->released);
+
+	memset(&ntb->dev, 0, sizeof(ntb->dev));
+	ntb->dev.bus = &ntb_bus;
+	ntb->dev.parent = &ntb->pdev->dev;
+	ntb->dev.release = ntb_dev_release;
+	dev_set_name(&ntb->dev, pci_name(ntb->pdev));
+
+	ntb->ctx = NULL;
+	ntb->ctx_ops = NULL;
+	spin_lock_init(&ntb->ctx_lock);
+
+	return device_register(&ntb->dev);
+}
+EXPORT_SYMBOL(ntb_register_device);
+
+void ntb_unregister_device(struct ntb_dev *ntb)
+{
+	device_unregister(&ntb->dev);
+	wait_for_completion(&ntb->released);
+}
+EXPORT_SYMBOL(ntb_unregister_device);
+
+int ntb_set_ctx(struct ntb_dev *ntb, void *ctx,
+		const struct ntb_ctx_ops *ctx_ops)
+{
+	unsigned long irqflags;
+
+	if (!ntb_ctx_ops_is_valid(ctx_ops))
+		return -EINVAL;
+	if (ntb->ctx_ops)
+		return -EINVAL;
+
+	spin_lock_irqsave(&ntb->ctx_lock, irqflags);
+	{
+		ntb->ctx = ctx;
+		ntb->ctx_ops = ctx_ops;
+	}
+	spin_unlock_irqrestore(&ntb->ctx_lock, irqflags);
+
+	return 0;
+}
+EXPORT_SYMBOL(ntb_set_ctx);
+
+void ntb_clear_ctx(struct ntb_dev *ntb)
+{
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&ntb->ctx_lock, irqflags);
+	{
+		ntb->ctx_ops = NULL;
+		ntb->ctx = NULL;
+	}
+	spin_unlock_irqrestore(&ntb->ctx_lock, irqflags);
+}
+EXPORT_SYMBOL(ntb_clear_ctx);
+
+void ntb_link_event(struct ntb_dev *ntb)
+{
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&ntb->ctx_lock, irqflags);
+	{
+		if (ntb->ctx_ops && ntb->ctx_ops->link_event)
+			ntb->ctx_ops->link_event(ntb->ctx);
+	}
+	spin_unlock_irqrestore(&ntb->ctx_lock, irqflags);
+}
+EXPORT_SYMBOL(ntb_link_event);
+
+void ntb_db_event(struct ntb_dev *ntb, int vector)
+{
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&ntb->ctx_lock, irqflags);
+	{
+		if (ntb->ctx_ops && ntb->ctx_ops->db_event)
+			ntb->ctx_ops->db_event(ntb->ctx, vector);
+	}
+	spin_unlock_irqrestore(&ntb->ctx_lock, irqflags);
+}
+EXPORT_SYMBOL(ntb_db_event);
+
+static int ntb_probe(struct device *dev)
+{
+	struct ntb_dev *ntb;
+	struct ntb_client *client;
+	int rc;
+
+	get_device(dev);
+	ntb = dev_ntb(dev);
+	client = drv_ntb_client(dev->driver);
+
+	rc = client->ops.probe(client, ntb);
+	if (rc)
+		put_device(dev);
+
+	return rc;
+}
+
+static int ntb_remove(struct device *dev)
+{
+	struct ntb_dev *ntb;
+	struct ntb_client *client;
+
+	if (dev->driver) {
+		ntb = dev_ntb(dev);
+		client = drv_ntb_client(dev->driver);
+
+		client->ops.remove(client, ntb);
+		put_device(dev);
+	}
+
+	return 0;
+}
+
+static void ntb_dev_release(struct device *dev)
+{
+	struct ntb_dev *ntb = dev_ntb(dev);
+
+	complete(&ntb->released);
+}
+
+static struct bus_type ntb_bus = {
+	.name = "ntb",
+	.probe = ntb_probe,
+	.remove = ntb_remove,
+};
+
+static int __init ntb_driver_init(void)
+{
+	return bus_register(&ntb_bus);
+}
+module_init(ntb_driver_init);
+
+static void __exit ntb_driver_exit(void)
+{
+	bus_unregister(&ntb_bus);
+}
+module_exit(ntb_driver_exit);
+
diff --git a/include/linux/ntb.h b/include/linux/ntb.h
new file mode 100644
index 000000000000..b02f72bb8e32
--- /dev/null
+++ b/include/linux/ntb.h
@@ -0,0 +1,984 @@
+/*
+ * 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 EMC 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.
+ *
+ *   This program is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *   General Public License for more details.
+ *
+ *   BSD LICENSE
+ *
+ *   Copyright (C) 2015 EMC 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 Linux driver
+ *
+ * Contact Information:
+ * Allen Hubbe <Allen.Hubbe@xxxxxxx>
+ */
+
+#ifndef _NTB_H_
+#define _NTB_H_
+
+#include <linux/completion.h>
+#include <linux/device.h>
+
+struct ntb_client;
+struct ntb_dev;
+struct pci_dev;
+
+/**
+ * enum ntb_topo - NTB connection topology
+ * @NTB_TOPO_NONE:	Topology is unknown or invalid.
+ * @NTB_TOPO_PRI:	On primary side of local ntb.
+ * @NTB_TOPO_SEC:	On secondary side of remote ntb.
+ * @NTB_TOPO_B2B_USD:	On primary side of local ntb upstream of remote ntb.
+ * @NTB_TOPO_B2B_DSD:	On primary side of local ntb downstream of remote ntb.
+ */
+enum ntb_topo {
+	NTB_TOPO_NONE = -1,
+	NTB_TOPO_PRI,
+	NTB_TOPO_SEC,
+	NTB_TOPO_B2B_USD,
+	NTB_TOPO_B2B_DSD,
+};
+
+static inline int ntb_topo_is_b2b(enum ntb_topo topo)
+{
+	switch ((int)topo) {
+	case NTB_TOPO_B2B_USD:
+	case NTB_TOPO_B2B_DSD:
+		return 1;
+	}
+	return 0;
+}
+
+static inline char *ntb_topo_string(enum ntb_topo topo)
+{
+	switch (topo) {
+	case NTB_TOPO_NONE:	return "NTB_TOPO_NONE";
+	case NTB_TOPO_PRI:	return "NTB_TOPO_PRI";
+	case NTB_TOPO_SEC:	return "NTB_TOPO_SEC";
+	case NTB_TOPO_B2B_USD:	return "NTB_TOPO_B2B_USD";
+	case NTB_TOPO_B2B_DSD:	return "NTB_TOPO_B2B_DSD";
+	}
+	return "NTB_TOPO_INVALID";
+}
+
+/**
+ * enum ntb_speed - NTB link training speed
+ * @NTB_SPEED_AUTO:	Request the max supported speed.
+ * @NTB_SPEED_NONE:	Link is not trained to any speed.
+ * @NTB_SPEED_GEN1:	Link is trained to gen1 speed.
+ * @NTB_SPEED_GEN2:	Link is trained to gen2 speed.
+ * @NTB_SPEED_GEN3:	Link is trained to gen3 speed.
+ */
+enum ntb_speed {
+	NTB_SPEED_AUTO = -1,
+	NTB_SPEED_NONE = 0,
+	NTB_SPEED_GEN1 = 1,
+	NTB_SPEED_GEN2 = 2,
+	NTB_SPEED_GEN3 = 3,
+};
+
+/**
+ * enum ntb_width - NTB link training width
+ * @NTB_WIDTH_AUTO:	Request the max supported width.
+ * @NTB_WIDTH_NONE:	Link is not trained to any width.
+ * @NTB_WIDTH_1:	Link is trained to 1 lane width.
+ * @NTB_WIDTH_2:	Link is trained to 2 lane width.
+ * @NTB_WIDTH_4:	Link is trained to 4 lane width.
+ * @NTB_WIDTH_8:	Link is trained to 8 lane width.
+ * @NTB_WIDTH_12:	Link is trained to 12 lane width.
+ * @NTB_WIDTH_16:	Link is trained to 16 lane width.
+ * @NTB_WIDTH_32:	Link is trained to 32 lane width.
+ */
+enum ntb_width {
+	NTB_WIDTH_AUTO = -1,
+	NTB_WIDTH_NONE = 0,
+	NTB_WIDTH_1 = 1,
+	NTB_WIDTH_2 = 2,
+	NTB_WIDTH_4 = 4,
+	NTB_WIDTH_8 = 8,
+	NTB_WIDTH_12 = 12,
+	NTB_WIDTH_16 = 16,
+	NTB_WIDTH_32 = 32,
+};
+
+/**
+ * struct ntb_client_ops - ntb client operations
+ * @probe:		Notify client of a new device.
+ * @remove:		Notify client to remove a device.
+ */
+struct ntb_client_ops {
+	int (*probe)(struct ntb_client *client, struct ntb_dev *ntb);
+	void (*remove)(struct ntb_client *client, struct ntb_dev *ntb);
+};
+
+static inline int ntb_client_ops_is_valid(const struct ntb_client_ops *ops)
+{
+	/* commented callbacks are not required: */
+	return
+		ops->probe			&&
+		ops->remove			&&
+		1;
+}
+
+/**
+ * struct ntb_ctx_ops - ntb driver context operations
+ * @link_event:		See ntb_link_event().
+ * @db_event:		See ntb_db_event().
+ */
+struct ntb_ctx_ops {
+	void (*link_event)(void *ctx);
+	void (*db_event)(void *ctx, int db_vector);
+};
+
+static inline int ntb_ctx_ops_is_valid(const struct ntb_ctx_ops *ops)
+{
+	/* commented callbacks are not required: */
+	return
+		/* ops->link_event		&& */
+		/* ops->db_event		&& */
+		1;
+}
+
+/**
+ * struct ntb_ctx_ops - ntb device operations
+ * @mw_count:		See ntb_mw_count().
+ * @mw_get_range:	See ntb_mw_get_range().
+ * @mw_set_trans:	See ntb_mw_set_trans().
+ * @mw_clear_trans:	See ntb_mw_clear_trans().
+ * @link_is_up:		See ntb_link_is_up().
+ * @link_enable:	See ntb_link_enable().
+ * @link_disable:	See ntb_link_disable().
+ * @db_is_unsafe:	See ntb_db_is_unsafe().
+ * @db_valid_mask:	See ntb_db_valid_mask().
+ * @db_vector_count:	See ntb_db_vector_count().
+ * @db_vector_mask:	See ntb_db_vector_mask().
+ * @db_read:		See ntb_db_read().
+ * @db_set:		See ntb_db_set().
+ * @db_clear:		See ntb_db_clear().
+ * @db_read_mask:	See ntb_db_read_mask().
+ * @db_set_mask:	See ntb_db_set_mask().
+ * @db_clear_mask:	See ntb_db_clear_mask().
+ * @peer_db_addr:	See ntb_peer_db_addr().
+ * @peer_db_read:	See ntb_peer_db_read().
+ * @peer_db_set:	See ntb_peer_db_set().
+ * @peer_db_clear:	See ntb_peer_db_clear().
+ * @peer_db_read_mask:	See ntb_peer_db_read_mask().
+ * @peer_db_set_mask:	See ntb_peer_db_set_mask().
+ * @peer_db_clear_mask:	See ntb_peer_db_clear_mask().
+ * @spad_is_unsafe:	See ntb_spad_is_unsafe().
+ * @spad_count:		See ntb_spad_count().
+ * @spad_read:		See ntb_spad_read().
+ * @spad_write:		See ntb_spad_write().
+ * @peer_spad_addr:	See ntb_peer_spad_addr().
+ * @peer_spad_read:	See ntb_peer_spad_read().
+ * @peer_spad_write:	See ntb_peer_spad_write().
+ */
+struct ntb_dev_ops {
+	int (*mw_count)(struct ntb_dev *ntb);
+	int (*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);
+	int (*mw_set_trans)(struct ntb_dev *ntb, int idx,
+			    dma_addr_t addr, resource_size_t size);
+	int (*mw_clear_trans)(struct ntb_dev *ntb, int idx);
+
+	int (*link_is_up)(struct ntb_dev *ntb,
+			  enum ntb_speed *speed, enum ntb_width *width);
+	int (*link_enable)(struct ntb_dev *ntb,
+			   enum ntb_speed max_speed, enum ntb_width max_width);
+	int (*link_disable)(struct ntb_dev *ntb);
+
+	int (*db_is_unsafe)(struct ntb_dev *ntb);
+	u64 (*db_valid_mask)(struct ntb_dev *ntb);
+	int (*db_vector_count)(struct ntb_dev *ntb);
+	u64 (*db_vector_mask)(struct ntb_dev *ntb, int db_vector);
+
+	u64 (*db_read)(struct ntb_dev *ntb);
+	int (*db_set)(struct ntb_dev *ntb, u64 db_bits);
+	int (*db_clear)(struct ntb_dev *ntb, u64 db_bits);
+
+	u64 (*db_read_mask)(struct ntb_dev *ntb);
+	int (*db_set_mask)(struct ntb_dev *ntb, u64 db_bits);
+	int (*db_clear_mask)(struct ntb_dev *ntb, u64 db_bits);
+
+	int (*peer_db_addr)(struct ntb_dev *ntb,
+			    phys_addr_t *db_addr, resource_size_t *db_size);
+	u64 (*peer_db_read)(struct ntb_dev *ntb);
+	int (*peer_db_set)(struct ntb_dev *ntb, u64 db_bits);
+	int (*peer_db_clear)(struct ntb_dev *ntb, u64 db_bits);
+
+	u64 (*peer_db_read_mask)(struct ntb_dev *ntb);
+	int (*peer_db_set_mask)(struct ntb_dev *ntb, u64 db_bits);
+	int (*peer_db_clear_mask)(struct ntb_dev *ntb, u64 db_bits);
+
+	int (*spad_is_unsafe)(struct ntb_dev *ntb);
+	int (*spad_count)(struct ntb_dev *ntb);
+
+	u32 (*spad_read)(struct ntb_dev *ntb, int idx);
+	int (*spad_write)(struct ntb_dev *ntb, int idx, u32 val);
+
+	int (*peer_spad_addr)(struct ntb_dev *ntb, int idx,
+			      phys_addr_t *spad_addr);
+	u32 (*peer_spad_read)(struct ntb_dev *ntb, int idx);
+	int (*peer_spad_write)(struct ntb_dev *ntb, int idx, u32 val);
+};
+
+static inline int ntb_dev_ops_is_valid(const struct ntb_dev_ops *ops)
+{
+	/* commented callbacks are not required: */
+	return
+		ops->mw_count				&&
+		ops->mw_get_range			&&
+		ops->mw_set_trans			&&
+		/* ops->mw_clear_trans			&& */
+		ops->link_is_up				&&
+		ops->link_enable			&&
+		ops->link_disable			&&
+		/* ops->db_is_unsafe			&& */
+		ops->db_valid_mask			&&
+
+		/* both set, or both unset */
+		(!ops->db_vector_count == !ops->db_vector_mask) &&
+
+		ops->db_read				&&
+		/* ops->db_set				&& */
+		ops->db_clear				&&
+		/* ops->db_read_mask			&& */
+		ops->db_set_mask			&&
+		ops->db_clear_mask			&&
+		ops->peer_db_addr			&&
+		/* ops->peer_db_read			&& */
+		ops->peer_db_set			&&
+		/* ops->peer_db_clear			&& */
+		/* ops->peer_db_read_mask		&& */
+		/* ops->peer_db_set_mask		&& */
+		/* ops->peer_db_clear_mask		&& */
+		/* ops->spad_is_unsafe			&& */
+		ops->spad_count				&&
+		ops->spad_read				&&
+		ops->spad_write				&&
+		ops->peer_spad_addr			&&
+		/* ops->peer_spad_read			&& */
+		ops->peer_spad_write			&&
+		1;
+}
+
+/**
+ * struct ntb_client - client interested in ntb devices
+ * @drv:		Linux driver object.
+ * @ops:		See &ntb_client_ops.
+ */
+struct ntb_client {
+	struct device_driver		drv;
+	const struct ntb_client_ops	ops;
+};
+
+#define drv_ntb_client(__drv) container_of((__drv), struct ntb_client, drv)
+
+/**
+ * struct ntb_device - ntb device
+ * @dev:		Linux device object.
+ * @pdev:		Pci device entry of the ntb.
+ * @topo:		Detected topology of the ntb.
+ * @ops:		See &ntb_dev_ops.
+ * @ctx:		See &ntb_ctx_ops.
+ * @ctx_ops:		See &ntb_ctx_ops.
+ */
+struct ntb_dev {
+	struct device			dev;
+	struct pci_dev			*pdev;
+	enum ntb_topo			topo;
+	const struct ntb_dev_ops	*ops;
+	void				*ctx;
+	const struct ntb_ctx_ops	*ctx_ops;
+
+	/* private: */
+
+	/* synchronize setting, clearing, and calling ctx_ops */
+	spinlock_t			ctx_lock;
+	/* block unregister until device is fully released */
+	struct completion		released;
+};
+
+#define dev_ntb(__dev) container_of((__dev), struct ntb_dev, dev)
+
+/**
+ * ntb_register_client() - register a client for interest in ntb devices
+ * @client:	Client context.
+ *
+ * The client will be added to the list of clients interested in ntb devices.
+ * The client will be notified of any ntb devices that are not already
+ * associated with a client, or if ntb devices are registered later.
+ *
+ * Return: Zero if the client is registered, otherwise an error number.
+ */
+#define ntb_register_client(client) \
+	__ntb_register_client((client), THIS_MODULE, KBUILD_MODNAME)
+
+int __ntb_register_client(struct ntb_client *client, struct module *mod,
+			  const char *mod_name);
+
+/**
+ * ntb_unregister_client() - unregister a client for interest in ntb devices
+ * @client:	Client context.
+ *
+ * The client will be removed from the list of clients interested in ntb
+ * devices.  If any ntb devices are associated with the client, the client will
+ * be notified to remove those devices.
+ */
+void ntb_unregister_client(struct ntb_client *client);
+
+#define module_ntb_client(__ntb_client) \
+	module_driver(__ntb_client, ntb_register_client, \
+			ntb_unregister_client)
+
+/**
+ * ntb_register_device() - register a ntb device
+ * @ntb:	NTB device context.
+ *
+ * The device will be added to the list of ntb devices.  If any clients are
+ * interested in ntb devices, each client will be notified of the ntb device,
+ * until at most one client accepts the device.
+ *
+ * Return: Zero if the device is registered, otherwise an error number.
+ */
+int ntb_register_device(struct ntb_dev *ntb);
+
+/**
+ * ntb_register_device() - unregister a ntb device
+ * @ntb:	NTB device context.
+ *
+ * The device will be removed from the list of ntb devices.  If the ntb device
+ * is associated with a client, the client will be notified to remove the
+ * device.
+ */
+void ntb_unregister_device(struct ntb_dev *ntb);
+
+/**
+ * ntb_set_ctx() - associate a driver context with an ntb device
+ * @ntb:	NTB device context.
+ * @ctx:	Driver context.
+ * @ctx_ops:	Driver context operations.
+ *
+ * Associate a driver context and operations with a ntb device.  The context is
+ * provided by the client driver, and the driver may associate a different
+ * context with each ntb device.
+ *
+ * Return: Zero if the context is associated, otherwise an error number.
+ */
+int ntb_set_ctx(struct ntb_dev *ntb, void *ctx,
+		const struct ntb_ctx_ops *ctx_ops);
+
+/**
+ * ntb_clear_ctx() - disassociate any driver context from an ntb device
+ * @ntb:	NTB device context.
+ *
+ * Clear any association that may exist between a driver context and the ntb
+ * device.
+ */
+void ntb_clear_ctx(struct ntb_dev *ntb);
+
+/**
+ * ntb_link_event() - notify driver context of a change in link status
+ * @ntb:	NTB device context.
+ *
+ * Notify the driver context that the link status may have changed.  The driver
+ * should call ntb_link_is_up() to get the current status.
+ */
+void ntb_link_event(struct ntb_dev *ntb);
+
+/**
+ * ntb_db_event() - notify driver context of a doorbell event
+ * @ntb:	NTB device context.
+ * @vector:	Interrupt vector number.
+ *
+ * Notify the driver context of a doorbell event.  If hardware supports
+ * multiple interrupt vectors for doorbells, the vector number indicates which
+ * vector received the interrupt.  The vector number is relative to the first
+ * vector used for doorbells, starting at zero, and must be less than
+ ** ntb_db_vector_count().  The driver may call ntb_db_read() to check which
+ * doorbell bits need service, and ntb_db_vector_mask() to determine which of
+ * those bits are associated with the vector number.
+ */
+void ntb_db_event(struct ntb_dev *ntb, int vector);
+
+/**
+ * ntb_mw_count() - get the number of memory windows
+ * @ntb:	NTB device context.
+ *
+ * Hardware and topology may support a different number of memory windows.
+ *
+ * Return: the number of memory windows.
+ */
+static inline int ntb_mw_count(struct ntb_dev *ntb)
+{
+	return ntb->ops->mw_count(ntb);
+}
+
+/**
+ * ntb_mw_get_range() - get the range of a memory window
+ * @ntb:	NTB device context.
+ * @idx:	Memory window number.
+ * @base:	OUT - the base address for mapping the memory window
+ * @size:	OUT - the size for mapping the memory window
+ * @align:	OUT - the base alignment for translating the memory window
+ * @align_size:	OUT - the size alignment for translating the memory window
+ *
+ * Get the range of a memory window.  NULL may be given for any output
+ * parameter if the value is not needed.  The base and size may be used for
+ * mapping the memory window, to access the peer memory.  The alignment and
+ * size may be used for translating the memory window, for the peer to access
+ * memory on the local system.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int 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)
+{
+	return ntb->ops->mw_get_range(ntb, idx, base, size,
+			align, align_size);
+}
+
+/**
+ * ntb_mw_set_trans() - set the translation of a memory window
+ * @ntb:	NTB device context.
+ * @idx:	Memory window number.
+ * @addr:	The dma address local memory to expose to the peer.
+ * @size:	The size of the local memory to expose to the peer.
+ *
+ * Set the translation of a memory window.  The peer may access local memory
+ * through the window starting at the address, up to the size.  The address
+ * must be aligned to the alignment specified by ntb_mw_get_range().  The size
+ * must be aligned to the size alignment specified by ntb_mw_get_range().
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_mw_set_trans(struct ntb_dev *ntb, int idx,
+				   dma_addr_t addr, resource_size_t size)
+{
+	return ntb->ops->mw_set_trans(ntb, idx, addr, size);
+}
+
+/**
+ * ntb_mw_clear_trans() - clear the translation of a memory window
+ * @ntb:	NTB device context.
+ * @idx:	Memory window number.
+ *
+ * Clear the translation of a memory window.  The peer may no longer access
+ * local memory through the window.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_mw_clear_trans(struct ntb_dev *ntb, int idx)
+{
+	if (!ntb->ops->mw_clear_trans)
+		return ntb->ops->mw_set_trans(ntb, idx, 0, 0);
+
+	return ntb->ops->mw_clear_trans(ntb, idx);
+}
+
+/**
+ * ntb_link_is_up() - get the current ntb link state
+ * @ntb:	NTB device context.
+ * @speed:	OUT - The link speed expressed as PCIe generation number.
+ * @width:	OUT - The link width expressed as the number of PCIe lanes.
+ *
+ * Set the translation of a memory window.  The peer may access local memory
+ * through the window starting at the address, up to the size.  The address
+ * must be aligned to the alignment specified by ntb_mw_get_range().  The size
+ * must be aligned to the size alignment specified by ntb_mw_get_range().
+ *
+ * Return: One if the link is up, zero if the link is down, otherwise a
+ *		negative value indicating the error number.
+ */
+static inline int ntb_link_is_up(struct ntb_dev *ntb,
+				 enum ntb_speed *speed, enum ntb_width *width)
+{
+	return ntb->ops->link_is_up(ntb, speed, width);
+}
+
+/**
+ * ntb_link_enable() - enable the link on the secondary side of the ntb
+ * @ntb:	NTB device context.
+ * @max_speed:	The maximum link speed expressed as PCIe generation number.
+ * @max_width:	The maximum link width expressed as the number of PCIe lanes.
+ *
+ * Enable the link on the secondary side of the ntb.  This can only be done
+ * from the primary side of the ntb in primary or b2b topology.  The ntb device
+ * should train the link to its maximum speed and width, or the requested speed
+ * and width, whichever is smaller, if supported.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_link_enable(struct ntb_dev *ntb,
+				  enum ntb_speed max_speed,
+				  enum ntb_width max_width)
+{
+	return ntb->ops->link_enable(ntb, max_speed, max_width);
+}
+
+/**
+ * ntb_link_disable() - disable the link on the secondary side of the ntb
+ * @ntb:	NTB device context.
+ *
+ * Disable the link on the secondary side of the ntb.  This can only be
+ * done from the primary side of the ntb in primary or b2b topology.  The ntb
+ * device should disable the link.  Returning from this call must indicate that
+ * a barrier has passed, though with no more writes may pass in either
+ * direction across the link, except if this call returns an error number.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_link_disable(struct ntb_dev *ntb)
+{
+	return ntb->ops->link_disable(ntb);
+}
+
+/**
+ * ntb_db_is_unsafe() - check if it is safe to use hardware doorbell
+ * @ntb:	NTB device context.
+ *
+ * It is possible for some ntb hardware to be affected by errata.  Hardware
+ * drivers can advise clients to avoid using doorbells.  Clients may ignore
+ * this advice, though caution is recommended.
+ *
+ * Return: Zero if it is safe to use doorbells, or One if it is not safe.
+ */
+static inline int ntb_db_is_unsafe(struct ntb_dev *ntb)
+{
+	if (!ntb->ops->db_is_unsafe)
+		return 0;
+
+	return ntb->ops->db_is_unsafe(ntb);
+}
+
+/**
+ * ntb_db_valid_mask() - get a mask of doorbell bits supported by the ntb
+ * @ntb:	NTB device context.
+ *
+ * Hardware may support different number or arrangement of doorbell bits.
+ *
+ * Return: A mask of doorbell bits supported by the ntb.
+ */
+static inline u64 ntb_db_valid_mask(struct ntb_dev *ntb)
+{
+	return ntb->ops->db_valid_mask(ntb);
+}
+
+/**
+ * ntb_db_vector_count() - get the number of doorbell interrupt vectors
+ * @ntb:	NTB device context.
+ *
+ * Hardware may support different number of interrupt vectors.
+ *
+ * Return: The number of doorbell interrupt vectors.
+ */
+static inline int ntb_db_vector_count(struct ntb_dev *ntb)
+{
+	if (!ntb->ops->db_vector_count)
+		return 1;
+
+	return ntb->ops->db_vector_count(ntb);
+}
+
+/**
+ * ntb_db_vector_mask() - get a mask of doorbell bits serviced by a vector
+ * @ntb:	NTB device context.
+ * @vector:	Doorbell vector number.
+ *
+ * Each interrupt vector may have a different number or arrangement of bits.
+ *
+ * Return: A mask of doorbell bits serviced by a vector.
+ */
+static inline u64 ntb_db_vector_mask(struct ntb_dev *ntb, int vector)
+{
+	if (!ntb->ops->db_vector_mask)
+		return ntb_db_valid_mask(ntb);
+
+	return ntb->ops->db_vector_mask(ntb, vector);
+}
+
+/**
+ * ntb_db_read() - read the local doorbell register
+ * @ntb:	NTB device context.
+ *
+ * Read the local doorbell register, and return the bits that are set.
+ *
+ * Return: The bits currently set in the local doorbell register.
+ */
+static inline u64 ntb_db_read(struct ntb_dev *ntb)
+{
+	return ntb->ops->db_read(ntb);
+}
+
+/**
+ * ntb_db_set() - set bits in the local doorbell register
+ * @ntb:	NTB device context.
+ * @db_bits:	Doorbell bits to set.
+ *
+ * Set bits in the local doorbell register, which may generate a local doorbell
+ * interrupt.  Bits that were already set must remain set.
+ *
+ * This is unusual, and hardware may not support it.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_db_set(struct ntb_dev *ntb, u64 db_bits)
+{
+	if (!ntb->ops->db_set)
+		return -EINVAL;
+
+	return ntb->ops->db_set(ntb, db_bits);
+}
+
+/**
+ * ntb_db_clear() - clear bits in the local doorbell register
+ * @ntb:	NTB device context.
+ * @db_bits:	Doorbell bits to clear.
+ *
+ * Clear bits in the local doorbell register, arming the bits for the next
+ * doorbell.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_db_clear(struct ntb_dev *ntb, u64 db_bits)
+{
+	return ntb->ops->db_clear(ntb, db_bits);
+}
+
+/**
+ * ntb_db_read_mask() - read the local doorbell mask
+ * @ntb:	NTB device context.
+ *
+ * Read the local doorbell mask register, and return the bits that are set.
+ *
+ * This is unusual, though hardware is likely to support it.
+ *
+ * Return: The bits currently set in the local doorbell mask register.
+ */
+static inline u64 ntb_db_read_mask(struct ntb_dev *ntb)
+{
+	if (!ntb->ops->db_read_mask)
+		return 0;
+
+	return ntb->ops->db_read_mask(ntb);
+}
+
+/**
+ * ntb_db_set_mask() - set bits in the local doorbell mask
+ * @ntb:	NTB device context.
+ * @db_bits:	Doorbell mask bits to set.
+ *
+ * Set bits in the local doorbell mask register, preventing doorbell interrupts
+ * from being generated for those doorbell bits.  Bits that were already set
+ * must remain set.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_db_set_mask(struct ntb_dev *ntb, u64 db_bits)
+{
+	return ntb->ops->db_set_mask(ntb, db_bits);
+}
+
+/**
+ * ntb_db_clear_mask() - clear bits in the local doorbell mask
+ * @ntb:	NTB device context.
+ * @db_bits:	Doorbell bits to clear.
+ *
+ * Clear bits in the local doorbell mask register, allowing doorbell interrupts
+ * from being generated for those doorbell bits.  If a doorbell bit is already
+ * set at the time the mask is cleared, and the corresponding mask bit is
+ * changed from set to clear, then the ntb driver must ensure that
+ * ntb_db_event() is called.  If the hardware does not generate the interrupt
+ * on clearing the mask bit, then the driver must call ntb_db_event() anyway.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_db_clear_mask(struct ntb_dev *ntb, u64 db_bits)
+{
+	return ntb->ops->db_clear_mask(ntb, db_bits);
+}
+
+/**
+ * ntb_peer_db_addr() - address and size of the peer doorbell register
+ * @ntb:	NTB device context.
+ * @db_addr:	OUT - The address of the peer doorbell register.
+ * @db_size:	OUT - The number of bytes to write the peer doorbell register.
+ *
+ * Return the address of the peer doorbell register.  This may be used, for
+ * example, by drivers that offload memory copy operations to a dma engine.
+ * The drivers may wish to ring the peer doorbell at the completion of memory
+ * copy operations.  For efficiency, and to simplify ordering of operations
+ * between the dma memory copies and the ringing doorbell, the driver may
+ * append one additional dma memory copy with the doorbell register as the
+ * destination, after the memory copy operations.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_peer_db_addr(struct ntb_dev *ntb,
+				   phys_addr_t *db_addr,
+				   resource_size_t *db_size)
+{
+	return ntb->ops->peer_db_addr(ntb, db_addr, db_size);
+}
+
+/**
+ * ntb_peer_db_read() - read the peer doorbell register
+ * @ntb:	NTB device context.
+ *
+ * Read the peer doorbell register, and return the bits that are set.
+ *
+ * This is unusual, and hardware may not support it.
+ *
+ * Return: The bits currently set in the peer doorbell register.
+ */
+static inline u64 ntb_peer_db_read(struct ntb_dev *ntb)
+{
+	if (!ntb->ops->peer_db_read)
+		return 0;
+
+	return ntb->ops->peer_db_read(ntb);
+}
+
+/**
+ * ntb_peer_db_set() - set bits in the peer doorbell register
+ * @ntb:	NTB device context.
+ * @db_bits:	Doorbell bits to set.
+ *
+ * Set bits in the peer doorbell register, which may generate a peer doorbell
+ * interrupt.  Bits that were already set must remain set.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_peer_db_set(struct ntb_dev *ntb, u64 db_bits)
+{
+	return ntb->ops->peer_db_set(ntb, db_bits);
+}
+
+/**
+ * ntb_peer_db_clear() - clear bits in the local doorbell register
+ * @ntb:	NTB device context.
+ * @db_bits:	Doorbell bits to clear.
+ *
+ * Clear bits in the peer doorbell register, arming the bits for the next
+ * doorbell.
+ *
+ * This is unusual, and hardware may not support it.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_peer_db_clear(struct ntb_dev *ntb, u64 db_bits)
+{
+	if (!ntb->ops->db_clear)
+		return -EINVAL;
+
+	return ntb->ops->peer_db_clear(ntb, db_bits);
+}
+
+/**
+ * ntb_peer_db_read_mask() - read the peer doorbell mask
+ * @ntb:	NTB device context.
+ *
+ * Read the peer doorbell mask register, and return the bits that are set.
+ *
+ * This is unusual, and hardware may not support it.
+ *
+ * Return: The bits currently set in the peer doorbell mask register.
+ */
+static inline u64 ntb_peer_db_read_mask(struct ntb_dev *ntb)
+{
+	if (!ntb->ops->db_read_mask)
+		return 0;
+
+	return ntb->ops->peer_db_read_mask(ntb);
+}
+
+/**
+ * ntb_peer_db_set_mask() - set bits in the peer doorbell mask
+ * @ntb:	NTB device context.
+ * @db_bits:	Doorbell mask bits to set.
+ *
+ * Set bits in the peer doorbell mask register, preventing doorbell interrupts
+ * from being generated for those doorbell bits.  Bits that were already set
+ * must remain set.
+ *
+ * This is unusual, and hardware may not support it.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_peer_db_set_mask(struct ntb_dev *ntb, u64 db_bits)
+{
+	if (!ntb->ops->db_set_mask)
+		return -EINVAL;
+
+	return ntb->ops->peer_db_set_mask(ntb, db_bits);
+}
+
+/**
+ * ntb_peer_db_clear_mask() - clear bits in the peer doorbell mask
+ * @ntb:	NTB device context.
+ * @db_bits:	Doorbell bits to clear.
+ *
+ * Clear bits in the peer doorbell mask register, allowing doorbell interrupts
+ * from being generated for those doorbell bits.  If the hardware does not
+ * generate the interrupt on clearing the mask bit, then the driver should not
+ * implement this function!
+ *
+ * This is unusual, and hardware may not support it.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_peer_db_clear_mask(struct ntb_dev *ntb, u64 db_bits)
+{
+	if (!ntb->ops->db_clear_mask)
+		return -EINVAL;
+
+	return ntb->ops->peer_db_clear_mask(ntb, db_bits);
+}
+
+/**
+ * ntb_spad_is_unsafe() - check if it is safe to use the hardware scratchpads
+ * @ntb:	NTB device context.
+ *
+ * It is possible for some ntb hardware to be affected by errata.  Hardware
+ * drivers can advise clients to avoid using scratchpads.  Clients may ignore
+ * this advice, though caution is recommended.
+ *
+ * Return: Zero if it is safe to use scratchpads, or One if it is not safe.
+ */
+static inline int ntb_spad_is_unsafe(struct ntb_dev *ntb)
+{
+	if (!ntb->ops->spad_is_unsafe)
+		return 0;
+
+	return ntb->ops->spad_is_unsafe(ntb);
+}
+
+/**
+ * ntb_mw_count() - get the number of scratchpads
+ * @ntb:	NTB device context.
+ *
+ * Hardware and topology may support a different number of scratchpads.
+ *
+ * Return: the number of scratchpads.
+ */
+static inline int ntb_spad_count(struct ntb_dev *ntb)
+{
+	return ntb->ops->spad_count(ntb);
+}
+
+/**
+ * ntb_spad_read() - read the local scratchpad register
+ * @ntb:	NTB device context.
+ * @idx:	Scratchpad index.
+ *
+ * Read the local scratchpad register, and return the value.
+ *
+ * Return: The value of the local scratchpad register.
+ */
+static inline u32 ntb_spad_read(struct ntb_dev *ntb, int idx)
+{
+	return ntb->ops->spad_read(ntb, idx);
+}
+
+/**
+ * ntb_spad_write() - write the local scratchpad register
+ * @ntb:	NTB device context.
+ * @idx:	Scratchpad index.
+ * @val:	Scratchpad value.
+ *
+ * Write the value to the local scratchpad register.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_spad_write(struct ntb_dev *ntb, int idx, u32 val)
+{
+	return ntb->ops->spad_write(ntb, idx, val);
+}
+
+/**
+ * ntb_peer_spad_addr() - address of the peer scratchpad register
+ * @ntb:	NTB device context.
+ * @idx:	Scratchpad index.
+ * @spad_addr:	OUT - The address of the peer scratchpad register.
+ *
+ * Return the address of the peer doorbell register.  This may be used, for
+ * example, by drivers that offload memory copy operations to a dma engine.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_peer_spad_addr(struct ntb_dev *ntb, int idx,
+				     phys_addr_t *spad_addr)
+{
+	return ntb->ops->peer_spad_addr(ntb, idx, spad_addr);
+}
+
+/**
+ * ntb_peer_spad_read() - read the peer scratchpad register
+ * @ntb:	NTB device context.
+ * @idx:	Scratchpad index.
+ *
+ * Read the peer scratchpad register, and return the value.
+ *
+ * Return: The value of the local scratchpad register.
+ */
+static inline u32 ntb_peer_spad_read(struct ntb_dev *ntb, int idx)
+{
+	return ntb->ops->peer_spad_read(ntb, idx);
+}
+
+/**
+ * ntb_peer_spad_write() - write the peer scratchpad register
+ * @ntb:	NTB device context.
+ * @idx:	Scratchpad index.
+ * @val:	Scratchpad value.
+ *
+ * Write the value to the peer scratchpad register.
+ *
+ * Return: Zero on success, otherwise an error number.
+ */
+static inline int ntb_peer_spad_write(struct ntb_dev *ntb, int idx, u32 val)
+{
+	return ntb->ops->peer_spad_write(ntb, idx, val);
+}
+
+#endif
-- 
2.4.0.rc0.43.gcf8a8c6

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