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 /*
  * 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.
  *   Copyright (C) 2016 T-Platforms. 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.
  *   Copyright (C) 2016 T-Platforms. 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@emc.com>
  */
 
 #ifndef _NTB_H_
 #define _NTB_H_
 
 #include <linux/completion.h>
 #include <linux/device.h>
 #include <linux/interrupt.h>
 
 struct ntb_client;
 struct ntb_dev;
 struct ntb_msi;
 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.
  * @NTB_TOPO_SWITCH:    Connected via a switch which supports ntb.
  * @NTB_TOPO_CROSSLINK: Connected via two symmetric switchecs
  */
 enum ntb_topo {
     NTB_TOPO_NONE = -1,
     NTB_TOPO_PRI,
     NTB_TOPO_SEC,
     NTB_TOPO_B2B_USD,
     NTB_TOPO_B2B_DSD,
     NTB_TOPO_SWITCH,
     NTB_TOPO_CROSSLINK,
 };
 
 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";
     case NTB_TOPO_SWITCH:       return "NTB_TOPO_SWITCH";
     case NTB_TOPO_CROSSLINK:    return "NTB_TOPO_CROSSLINK";
     }
     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.
  * @NTB_SPEED_GEN4: Link is trained to gen4 speed.
  */
 enum ntb_speed {
     NTB_SPEED_AUTO = -1,
     NTB_SPEED_NONE = 0,
     NTB_SPEED_GEN1 = 1,
     NTB_SPEED_GEN2 = 2,
     NTB_SPEED_GEN3 = 3,
     NTB_SPEED_GEN4 = 4
 };
 
 /**
  * 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,
 };
 
 /**
  * enum ntb_default_port - NTB default port number
  * @NTB_PORT_PRI_USD:   Default port of the NTB_TOPO_PRI/NTB_TOPO_B2B_USD
  *          topologies
  * @NTB_PORT_SEC_DSD:   Default port of the NTB_TOPO_SEC/NTB_TOPO_B2B_DSD
  *          topologies
  */
 enum ntb_default_port {
     NTB_PORT_PRI_USD,
     NTB_PORT_SEC_DSD
 };
 #define NTB_DEF_PEER_CNT    (1)
 #define NTB_DEF_PEER_IDX    (0)
 
 /**
  * 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().
  * @msg_event:      See ntb_msg_event().
  */
 struct ntb_ctx_ops {
     void (*link_event)(void *ctx);
     void (*db_event)(void *ctx, int db_vector);
     void (*msg_event)(void *ctx);
 };
 
 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        && */
         /* ops->msg_event       && */
         1;
 }
 
 /**
  * struct ntb_dev_ops - ntb device operations
  * @port_number:    See ntb_port_number().
  * @peer_port_count:    See ntb_peer_port_count().
  * @peer_port_number:   See ntb_peer_port_number().
  * @peer_port_idx:  See ntb_peer_port_idx().
  * @link_is_up:     See ntb_link_is_up().
  * @link_enable:    See ntb_link_enable().
  * @link_disable:   See ntb_link_disable().
  * @mw_count:       See ntb_mw_count().
  * @mw_get_align:   See ntb_mw_get_align().
  * @mw_set_trans:   See ntb_mw_set_trans().
  * @mw_clear_trans: See ntb_mw_clear_trans().
  * @peer_mw_count:  See ntb_peer_mw_count().
  * @peer_mw_get_addr:   See ntb_peer_mw_get_addr().
  * @peer_mw_set_trans:  See ntb_peer_mw_set_trans().
  * @peer_mw_clear_trans:See ntb_peer_mw_clear_trans().
  * @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().
  * @msg_count:      See ntb_msg_count().
  * @msg_inbits:     See ntb_msg_inbits().
  * @msg_outbits:    See ntb_msg_outbits().
  * @msg_read_sts:   See ntb_msg_read_sts().
  * @msg_clear_sts:  See ntb_msg_clear_sts().
  * @msg_set_mask:   See ntb_msg_set_mask().
  * @msg_clear_mask: See ntb_msg_clear_mask().
  * @msg_read:       See ntb_msg_read().
  * @peer_msg_write: See ntb_peer_msg_write().
  */
 struct ntb_dev_ops {
     int (*port_number)(struct ntb_dev *ntb);
     int (*peer_port_count)(struct ntb_dev *ntb);
     int (*peer_port_number)(struct ntb_dev *ntb, int pidx);
     int (*peer_port_idx)(struct ntb_dev *ntb, int port);
 
     u64 (*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 (*mw_count)(struct ntb_dev *ntb, int pidx);
     int (*mw_get_align)(struct ntb_dev *ntb, int pidx, int widx,
                 resource_size_t *addr_align,
                 resource_size_t *size_align,
                 resource_size_t *size_max);
     int (*mw_set_trans)(struct ntb_dev *ntb, int pidx, int widx,
                 dma_addr_t addr, resource_size_t size);
     int (*mw_clear_trans)(struct ntb_dev *ntb, int pidx, int widx);
     int (*peer_mw_count)(struct ntb_dev *ntb);
     int (*peer_mw_get_addr)(struct ntb_dev *ntb, int widx,
                 phys_addr_t *base, resource_size_t *size);
     int (*peer_mw_set_trans)(struct ntb_dev *ntb, int pidx, int widx,
                  u64 addr, resource_size_t size);
     int (*peer_mw_clear_trans)(struct ntb_dev *ntb, int pidx, int widx);
 
     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 *db_data, int db_bit);
     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 sidx);
     int (*spad_write)(struct ntb_dev *ntb, int sidx, u32 val);
 
     int (*peer_spad_addr)(struct ntb_dev *ntb, int pidx, int sidx,
                   phys_addr_t *spad_addr);
     u32 (*peer_spad_read)(struct ntb_dev *ntb, int pidx, int sidx);
     int (*peer_spad_write)(struct ntb_dev *ntb, int pidx, int sidx,
                    u32 val);
 
     int (*msg_count)(struct ntb_dev *ntb);
     u64 (*msg_inbits)(struct ntb_dev *ntb);
     u64 (*msg_outbits)(struct ntb_dev *ntb);
     u64 (*msg_read_sts)(struct ntb_dev *ntb);
     int (*msg_clear_sts)(struct ntb_dev *ntb, u64 sts_bits);
     int (*msg_set_mask)(struct ntb_dev *ntb, u64 mask_bits);
     int (*msg_clear_mask)(struct ntb_dev *ntb, u64 mask_bits);
     u32 (*msg_read)(struct ntb_dev *ntb, int *pidx, int midx);
     int (*peer_msg_write)(struct ntb_dev *ntb, int pidx, int midx, u32 msg);
 };
 
 static inline int ntb_dev_ops_is_valid(const struct ntb_dev_ops *ops)
 {
     /* commented callbacks are not required: */
     return
         /* Port operations are required for multiport devices */
         !ops->peer_port_count == !ops->port_number  &&
         !ops->peer_port_number == !ops->port_number &&
         !ops->peer_port_idx == !ops->port_number    &&
 
         /* Link operations are required */
         ops->link_is_up             &&
         ops->link_enable            &&
         ops->link_disable           &&
 
         /* One or both MW interfaces should be developed */
         ops->mw_count               &&
         ops->mw_get_align           &&
         (ops->mw_set_trans          ||
          ops->peer_mw_set_trans)        &&
         /* ops->mw_clear_trans          && */
         ops->peer_mw_count          &&
         ops->peer_mw_get_addr           &&
         /* ops->peer_mw_clear_trans     && */
 
         /* Doorbell operations are mostly required */
         /* 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      && */
 
         /* Scrachpads interface is optional */
         /* !ops->spad_is_unsafe == !ops->spad_count && */
         !ops->spad_read == !ops->spad_count     &&
         !ops->spad_write == !ops->spad_count        &&
         /* !ops->peer_spad_addr == !ops->spad_count && */
         /* !ops->peer_spad_read == !ops->spad_count && */
         !ops->peer_spad_write == !ops->spad_count   &&
 
         /* Messaging interface is optional */
         !ops->msg_inbits == !ops->msg_count     &&
         !ops->msg_outbits == !ops->msg_count        &&
         !ops->msg_read_sts == !ops->msg_count       &&
         !ops->msg_clear_sts == !ops->msg_count      &&
         /* !ops->msg_set_mask == !ops->msg_count    && */
         /* !ops->msg_clear_mask == !ops->msg_count  && */
         !ops->msg_read == !ops->msg_count       &&
         !ops->peer_msg_write == !ops->msg_count     &&
         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_dev - 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;
 
 #ifdef CONFIG_NTB_MSI
     struct ntb_msi *msi;
 #endif
 };
 #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_unregister_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_msg_event() - notify driver context of a message event
  * @ntb:    NTB device context.
  *
  * Notify the driver context of a message event.  If hardware supports
  * message registers, this event indicates, that a new message arrived in
  * some incoming message register or last sent message couldn't be delivered.
  * The events can be masked/unmasked by the methods ntb_msg_set_mask() and
  * ntb_msg_clear_mask().
  */
 void ntb_msg_event(struct ntb_dev *ntb);
 
 /**
  * ntb_default_port_number() - get the default local port number
  * @ntb:    NTB device context.
  *
  * If hardware driver doesn't specify port_number() callback method, the NTB
  * is considered with just two ports. So this method returns default local
  * port number in compliance with topology.
  *
  * NOTE Don't call this method directly. The ntb_port_number() function should
  * be used instead.
  *
  * Return: the default local port number
  */
 int ntb_default_port_number(struct ntb_dev *ntb);
 
 /**
  * ntb_default_port_count() - get the default number of peer device ports
  * @ntb:    NTB device context.
  *
  * By default hardware driver supports just one peer device.
  *
  * NOTE Don't call this method directly. The ntb_peer_port_count() function
  * should be used instead.
  *
  * Return: the default number of peer ports
  */
 int ntb_default_peer_port_count(struct ntb_dev *ntb);
 
 /**
  * ntb_default_peer_port_number() - get the default peer port by given index
  * @ntb:    NTB device context.
  * @idx:    Peer port index (should not differ from zero).
  *
  * By default hardware driver supports just one peer device, so this method
  * shall return the corresponding value from enum ntb_default_port.
  *
  * NOTE Don't call this method directly. The ntb_peer_port_number() function
  * should be used instead.
  *
  * Return: the peer device port or negative value indicating an error
  */
 int ntb_default_peer_port_number(struct ntb_dev *ntb, int pidx);
 
 /**
  * ntb_default_peer_port_idx() - get the default peer device port index by
  *               given port number
  * @ntb:    NTB device context.
  * @port:   Peer port number (should be one of enum ntb_default_port).
  *
  * By default hardware driver supports just one peer device, so while
  * specified port-argument indicates peer port from enum ntb_default_port,
  * the return value shall be zero.
  *
  * NOTE Don't call this method directly. The ntb_peer_port_idx() function
  * should be used instead.
  *
  * Return: the peer port index or negative value indicating an error
  */
 int ntb_default_peer_port_idx(struct ntb_dev *ntb, int port);
 
 /**
  * ntb_port_number() - get the local port number
  * @ntb:    NTB device context.
  *
  * Hardware must support at least simple two-ports ntb connection
  *
  * Return: the local port number
  */
 static inline int ntb_port_number(struct ntb_dev *ntb)
 {
     if (!ntb->ops->port_number)
         return ntb_default_port_number(ntb);
 
     return ntb->ops->port_number(ntb);
 }
 /**
  * ntb_peer_port_count() - get the number of peer device ports
  * @ntb:    NTB device context.
  *
  * Hardware may support an access to memory of several remote domains
  * over multi-port NTB devices. This method returns the number of peers,
  * local device can have shared memory with.
  *
  * Return: the number of peer ports
  */
 static inline int ntb_peer_port_count(struct ntb_dev *ntb)
 {
     if (!ntb->ops->peer_port_count)
         return ntb_default_peer_port_count(ntb);
 
     return ntb->ops->peer_port_count(ntb);
 }
 
 /**
  * ntb_peer_port_number() - get the peer port by given index
  * @ntb:    NTB device context.
  * @pidx:   Peer port index.
  *
  * Peer ports are continuously enumerated by NTB API logic, so this method
  * lets to retrieve port real number by its index.
  *
  * Return: the peer device port or negative value indicating an error
  */
 static inline int ntb_peer_port_number(struct ntb_dev *ntb, int pidx)
 {
     if (!ntb->ops->peer_port_number)
         return ntb_default_peer_port_number(ntb, pidx);
 
     return ntb->ops->peer_port_number(ntb, pidx);
 }
 
 /**
  * ntb_logical_port_number() - get the logical port number of the local port
  * @ntb:    NTB device context.
  *
  * The Logical Port Number is defined to be a unique number for each
  * port starting from zero through to the number of ports minus one.
  * This is in contrast to the Port Number where each port can be assigned
  * any unique physical number by the hardware.
  *
  * The logical port number is useful for calculating the resource indexes
  * used by peers.
  *
  * Return: the logical port number or negative value indicating an error
  */
 static inline int ntb_logical_port_number(struct ntb_dev *ntb)
 {
     int lport = ntb_port_number(ntb);
     int pidx;
 
     if (lport < 0)
         return lport;
 
     for (pidx = 0; pidx < ntb_peer_port_count(ntb); pidx++)
         if (lport <= ntb_peer_port_number(ntb, pidx))
             return pidx;
 
     return pidx;
 }
 
 /**
  * ntb_peer_logical_port_number() - get the logical peer port by given index
  * @ntb:    NTB device context.
  * @pidx:   Peer port index.
  *
  * The Logical Port Number is defined to be a unique number for each
  * port starting from zero through to the number of ports minus one.
  * This is in contrast to the Port Number where each port can be assigned
  * any unique physical number by the hardware.
  *
  * The logical port number is useful for calculating the resource indexes
  * used by peers.
  *
  * Return: the peer's logical port number or negative value indicating an error
  */
 static inline int ntb_peer_logical_port_number(struct ntb_dev *ntb, int pidx)
 {
     if (ntb_peer_port_number(ntb, pidx) < ntb_port_number(ntb))
         return pidx;
     else
         return pidx + 1;
 }
 
 /**
  * ntb_peer_port_idx() - get the peer device port index by given port number
  * @ntb:    NTB device context.
  * @port:   Peer port number.
  *
  * Inverse operation of ntb_peer_port_number(), so one can get port index
  * by specified port number.
  *
  * Return: the peer port index or negative value indicating an error
  */
 static inline int ntb_peer_port_idx(struct ntb_dev *ntb, int port)
 {
     if (!ntb->ops->peer_port_idx)
         return ntb_default_peer_port_idx(ntb, port);
 
     return ntb->ops->peer_port_idx(ntb, port);
 }
 
 /**
  * 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.
  *
  * Get the current state of the ntb link.  It is recommended to query the link
  * state once after every link event.  It is safe to query the link state in
  * the context of the link event callback.
  *
  * Return: bitfield of indexed ports link state: bit is set/cleared if the
  *         link is up/down respectively.
  */
 static inline u64 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 local port ntb connection
  * @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 NTB/PCIe link on the local or remote (for bridge-to-bridge
  * topology) side of the bridge. If it's supported the ntb device should train
  * the link to its maximum speed and width, or the requested speed and width,
  * whichever is smaller. Some hardware doesn't support PCIe link training, so
  * the last two arguments will be ignored then.
  *
  * 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 local port ntb connection
  * @ntb:    NTB device context.
  *
  * Disable the link on the local or remote (for b2b topology) of the ntb.
  * 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_mw_count() - get the number of inbound memory windows, which could
  *                  be created for a specified peer device
  * @ntb:    NTB device context.
  * @pidx:   Port index of peer device.
  *
  * Hardware and topology may support a different number of memory windows.
  * Moreover different peer devices can support different number of memory
  * windows. Simply speaking this method returns the number of possible inbound
  * memory windows to share with specified peer device. Note: this may return
  * zero if the link is not up yet.
  *
  * Return: the number of memory windows.
  */
 static inline int ntb_mw_count(struct ntb_dev *ntb, int pidx)
 {
     return ntb->ops->mw_count(ntb, pidx);
 }
 
 /**
  * ntb_mw_get_align() - get the restriction parameters of inbound memory window
  * @ntb:    NTB device context.
  * @pidx:   Port index of peer device.
  * @widx:   Memory window index.
  * @addr_align: OUT - the base alignment for translating the memory window
  * @size_align: OUT - the size alignment for translating the memory window
  * @size_max:   OUT - the maximum size of the memory window
  *
  * Get the alignments of an inbound memory window with specified index.
  * NULL may be given for any output parameter if the value is not needed.
  * The alignment and size parameters may be used for allocation of proper
  * shared memory. Note: this must only be called when the link is up.
  *
  * Return: Zero on success, otherwise a negative error number.
  */
 static inline int ntb_mw_get_align(struct ntb_dev *ntb, int pidx, int widx,
                    resource_size_t *addr_align,
                    resource_size_t *size_align,
                    resource_size_t *size_max)
 {
     if (!(ntb_link_is_up(ntb, NULL, NULL) & BIT_ULL(pidx)))
         return -ENOTCONN;
 
     return ntb->ops->mw_get_align(ntb, pidx, widx, addr_align, size_align,
                       size_max);
 }
 
 /**
  * ntb_mw_set_trans() - set the translation of an inbound memory window
  * @ntb:    NTB device context.
  * @pidx:   Port index of peer device.
  * @widx:   Memory window index.
  * @addr:   The dma address of 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
  * and size must be aligned in compliance with restrictions of
  * ntb_mw_get_align(). The region size should not exceed the size_max parameter
  * of that method.
  *
  * This method may not be implemented due to the hardware specific memory
  * windows interface.
  *
  * Return: Zero on success, otherwise an error number.
  */
 static inline int ntb_mw_set_trans(struct ntb_dev *ntb, int pidx, int widx,
                    dma_addr_t addr, resource_size_t size)
 {
     if (!ntb->ops->mw_set_trans)
         return 0;
 
     return ntb->ops->mw_set_trans(ntb, pidx, widx, addr, size);
 }
 
 /**
  * ntb_mw_clear_trans() - clear the translation address of an inbound memory
  *                        window
  * @ntb:    NTB device context.
  * @pidx:   Port index of peer device.
  * @widx:   Memory window index.
  *
  * Clear the translation of an inbound 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 pidx, int widx)
 {
     if (!ntb->ops->mw_clear_trans)
         return ntb_mw_set_trans(ntb, pidx, widx, 0, 0);
 
     return ntb->ops->mw_clear_trans(ntb, pidx, widx);
 }
 
 /**
  * ntb_peer_mw_count() - get the number of outbound memory windows, which could
  *                       be mapped to access a shared memory
  * @ntb:    NTB device context.
  *
  * Hardware and topology may support a different number of memory windows.
  * This method returns the number of outbound memory windows supported by
  * local device.
  *
  * Return: the number of memory windows.
  */
 static inline int ntb_peer_mw_count(struct ntb_dev *ntb)
 {
     return ntb->ops->peer_mw_count(ntb);
 }
 
 /**
  * ntb_peer_mw_get_addr() - get map address of an outbound memory window
  * @ntb:    NTB device context.
  * @widx:   Memory window index (within ntb_peer_mw_count() return value).
  * @base:   OUT - the base address of mapping region.
  * @size:   OUT - the size of mapping region.
  *
  * Get base and size of memory region to map.  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.
  *
  * Return: Zero on success, otherwise a negative error number.
  */
 static inline int ntb_peer_mw_get_addr(struct ntb_dev *ntb, int widx,
                       phys_addr_t *base, resource_size_t *size)
 {
     return ntb->ops->peer_mw_get_addr(ntb, widx, base, size);
 }
 
 /**
  * ntb_peer_mw_set_trans() - set a translation address of a memory window
  *                           retrieved from a peer device
  * @ntb:    NTB device context.
  * @pidx:   Port index of peer device the translation address received from.
  * @widx:   Memory window index.
  * @addr:   The dma address of the shared memory to access.
  * @size:   The size of the shared memory to access.
  *
  * Set the translation of an outbound memory window.  The local device may
  * access shared memory allocated by a peer device sent the address.
  *
  * This method may not be implemented due to the hardware specific memory
  * windows interface, so a translation address can be only set on the side,
  * where shared memory (inbound memory windows) is allocated.
  *
  * Return: Zero on success, otherwise an error number.
  */
 static inline int ntb_peer_mw_set_trans(struct ntb_dev *ntb, int pidx, int widx,
                     u64 addr, resource_size_t size)
 {
     if (!ntb->ops->peer_mw_set_trans)
         return 0;
 
     return ntb->ops->peer_mw_set_trans(ntb, pidx, widx, addr, size);
 }
 
 /**
  * ntb_peer_mw_clear_trans() - clear the translation address of an outbound
  *                             memory window
  * @ntb:    NTB device context.
  * @pidx:   Port index of peer device.
  * @widx:   Memory window index.
  *
  * Clear the translation of a outbound memory window.  The local device may no
  * longer access a shared memory through the window.
  *
  * This method may not be implemented due to the hardware specific memory
  * windows interface.
  *
  * Return: Zero on success, otherwise an error number.
  */
 static inline int ntb_peer_mw_clear_trans(struct ntb_dev *ntb, int pidx,
                       int widx)
 {
     if (!ntb->ops->peer_mw_clear_trans)
         return ntb_peer_mw_set_trans(ntb, pidx, widx, 0, 0);
 
     return ntb->ops->peer_mw_clear_trans(ntb, pidx, widx);
 }
 
 /**
  * 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.
  * @db_data:    OUT - The data of peer doorbell register
  * @db_bit:     door bell bit number
  *
  * 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,
                    u64 *db_data, int db_bit)
 {
     if (!ntb->ops->peer_db_addr)
         return -EINVAL;
 
     return ntb->ops->peer_db_addr(ntb, db_addr, db_size, db_data, db_bit);
 }
 
 /**
  * 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 peer 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_spad_count() - get the number of scratchpads
  * @ntb:    NTB device context.
  *
  * Hardware and topology may support a different number of scratchpads.
  * Although it must be the same for all ports per NTB device.
  *
  * Return: the number of scratchpads.
  */
 static inline int ntb_spad_count(struct ntb_dev *ntb)
 {
     if (!ntb->ops->spad_count)
         return 0;
 
     return ntb->ops->spad_count(ntb);
 }
 
 /**
  * ntb_spad_read() - read the local scratchpad register
  * @ntb:    NTB device context.
  * @sidx:   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 sidx)
 {
     if (!ntb->ops->spad_read)
         return ~(u32)0;
 
     return ntb->ops->spad_read(ntb, sidx);
 }
 
 /**
  * ntb_spad_write() - write the local scratchpad register
  * @ntb:    NTB device context.
  * @sidx:   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 sidx, u32 val)
 {
     if (!ntb->ops->spad_write)
         return -EINVAL;
 
     return ntb->ops->spad_write(ntb, sidx, val);
 }
 
 /**
  * ntb_peer_spad_addr() - address of the peer scratchpad register
  * @ntb:    NTB device context.
  * @pidx:   Port index of peer device.
  * @sidx:   Scratchpad index.
  * @spad_addr:  OUT - The address of the peer scratchpad register.
  *
  * Return the address of the peer scratchpad 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 pidx, int sidx,
                      phys_addr_t *spad_addr)
 {
     if (!ntb->ops->peer_spad_addr)
         return -EINVAL;
 
     return ntb->ops->peer_spad_addr(ntb, pidx, sidx, spad_addr);
 }
 
 /**
  * ntb_peer_spad_read() - read the peer scratchpad register
  * @ntb:    NTB device context.
  * @pidx:   Port index of peer device.
  * @sidx:   Scratchpad index.
  *
  * Read the peer scratchpad register, and return the value.
  *
  * Return: The value of the peer scratchpad register.
  */
 static inline u32 ntb_peer_spad_read(struct ntb_dev *ntb, int pidx, int sidx)
 {
     if (!ntb->ops->peer_spad_read)
         return ~(u32)0;
 
     return ntb->ops->peer_spad_read(ntb, pidx, sidx);
 }
 
 /**
  * ntb_peer_spad_write() - write the peer scratchpad register
  * @ntb:    NTB device context.
  * @pidx:   Port index of peer device.
  * @sidx:   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 pidx, int sidx,
                       u32 val)
 {
     if (!ntb->ops->peer_spad_write)
         return -EINVAL;
 
     return ntb->ops->peer_spad_write(ntb, pidx, sidx, val);
 }
 
 /**
  * ntb_msg_count() - get the number of message registers
  * @ntb:    NTB device context.
  *
  * Hardware may support a different number of message registers.
  *
  * Return: the number of message registers.
  */
 static inline int ntb_msg_count(struct ntb_dev *ntb)
 {
     if (!ntb->ops->msg_count)
         return 0;
 
     return ntb->ops->msg_count(ntb);
 }
 
 /**
  * ntb_msg_inbits() - get a bitfield of inbound message registers status
  * @ntb:    NTB device context.
  *
  * The method returns the bitfield of status and mask registers, which related
  * to inbound message registers.
  *
  * Return: bitfield of inbound message registers.
  */
 static inline u64 ntb_msg_inbits(struct ntb_dev *ntb)
 {
     if (!ntb->ops->msg_inbits)
         return 0;
 
     return ntb->ops->msg_inbits(ntb);
 }
 
 /**
  * ntb_msg_outbits() - get a bitfield of outbound message registers status
  * @ntb:    NTB device context.
  *
  * The method returns the bitfield of status and mask registers, which related
  * to outbound message registers.
  *
  * Return: bitfield of outbound message registers.
  */
 static inline u64 ntb_msg_outbits(struct ntb_dev *ntb)
 {
     if (!ntb->ops->msg_outbits)
         return 0;
 
     return ntb->ops->msg_outbits(ntb);
 }
 
 /**
  * ntb_msg_read_sts() - read the message registers status
  * @ntb:    NTB device context.
  *
  * Read the status of message register. Inbound and outbound message registers
  * related bits can be filtered by masks retrieved from ntb_msg_inbits() and
  * ntb_msg_outbits().
  *
  * Return: status bits of message registers
  */
 static inline u64 ntb_msg_read_sts(struct ntb_dev *ntb)
 {
     if (!ntb->ops->msg_read_sts)
         return 0;
 
     return ntb->ops->msg_read_sts(ntb);
 }
 
 /**
  * ntb_msg_clear_sts() - clear status bits of message registers
  * @ntb:    NTB device context.
  * @sts_bits:   Status bits to clear.
  *
  * Clear bits in the status register.
  *
  * Return: Zero on success, otherwise a negative error number.
  */
 static inline int ntb_msg_clear_sts(struct ntb_dev *ntb, u64 sts_bits)
 {
     if (!ntb->ops->msg_clear_sts)
         return -EINVAL;
 
     return ntb->ops->msg_clear_sts(ntb, sts_bits);
 }
 
 /**
  * ntb_msg_set_mask() - set mask of message register status bits
  * @ntb:    NTB device context.
  * @mask_bits:  Mask bits.
  *
  * Mask the message registers status bits from raising the message event.
  *
  * Return: Zero on success, otherwise a negative error number.
  */
 static inline int ntb_msg_set_mask(struct ntb_dev *ntb, u64 mask_bits)
 {
     if (!ntb->ops->msg_set_mask)
         return -EINVAL;
 
     return ntb->ops->msg_set_mask(ntb, mask_bits);
 }
 
 /**
  * ntb_msg_clear_mask() - clear message registers mask
  * @ntb:    NTB device context.
  * @mask_bits:  Mask bits to clear.
  *
  * Clear bits in the message events mask register.
  *
  * Return: Zero on success, otherwise a negative error number.
  */
 static inline int ntb_msg_clear_mask(struct ntb_dev *ntb, u64 mask_bits)
 {
     if (!ntb->ops->msg_clear_mask)
         return -EINVAL;
 
     return ntb->ops->msg_clear_mask(ntb, mask_bits);
 }
 
 /**
  * ntb_msg_read() - read inbound message register with specified index
  * @ntb:    NTB device context.
  * @pidx:   OUT - Port index of peer device a message retrieved from
  * @midx:   Message register index
  *
  * Read data from the specified message register. Source port index of a
  * message is retrieved as well.
  *
  * Return: The value of the inbound message register.
  */
 static inline u32 ntb_msg_read(struct ntb_dev *ntb, int *pidx, int midx)
 {
     if (!ntb->ops->msg_read)
         return ~(u32)0;
 
     return ntb->ops->msg_read(ntb, pidx, midx);
 }
 
 /**
  * ntb_peer_msg_write() - write data to the specified peer message register
  * @ntb:    NTB device context.
  * @pidx:   Port index of peer device a message being sent to
  * @midx:   Message register index
  * @msg:    Data to send
  *
  * Send data to a specified peer device using the defined message register.
  * Message event can be raised if the midx registers isn't empty while
  * calling this method and the corresponding interrupt isn't masked.
  *
  * Return: Zero on success, otherwise a negative error number.
  */
 static inline int ntb_peer_msg_write(struct ntb_dev *ntb, int pidx, int midx,
                      u32 msg)
 {
     if (!ntb->ops->peer_msg_write)
         return -EINVAL;
 
     return ntb->ops->peer_msg_write(ntb, pidx, midx, msg);
 }
 
 /**
  * ntb_peer_resource_idx() - get a resource index for a given peer idx
  * @ntb:    NTB device context.
  * @pidx:   Peer port index.
  *
  * When constructing a graph of peers, each remote peer must use a different
  * resource index (mw, doorbell, etc) to communicate with each other
  * peer.
  *
  * In a two peer system, this function should always return 0 such that
  * resource 0 points to the remote peer on both ports.
  *
  * In a 5 peer system, this function will return the following matrix
  *
  * pidx \ port    0    1    2    3    4
  * 0              0    0    1    2    3
  * 1              0    1    1    2    3
  * 2              0    1    2    2    3
  * 3              0    1    2    3    3
  *
  * For example, if this function is used to program peer's memory
  * windows, port 0 will program MW 0 on all it's peers to point to itself.
  * port 1 will program MW 0 in port 0 to point to itself and MW 1 on all
  * other ports. etc.
  *
  * For the legacy two host case, ntb_port_number() and ntb_peer_port_number()
  * both return zero and therefore this function will always return zero.
  * So MW 0 on each host would be programmed to point to the other host.
  *
  * Return: the resource index to use for that peer.
  */
 static inline int ntb_peer_resource_idx(struct ntb_dev *ntb, int pidx)
 {
     int local_port, peer_port;
 
     if (pidx >= ntb_peer_port_count(ntb))
         return -EINVAL;
 
     local_port = ntb_logical_port_number(ntb);
     peer_port = ntb_peer_logical_port_number(ntb, pidx);
 
     if (peer_port < local_port)
         return local_port - 1;
     else
         return local_port;
 }
 
 /**
  * ntb_peer_highest_mw_idx() - get a memory window index for a given peer idx
  *  using the highest index memory windows first
  *
  * @ntb:    NTB device context.
  * @pidx:   Peer port index.
  *
  * Like ntb_peer_resource_idx(), except it returns indexes starting with
  * last memory window index.
  *
  * Return: the resource index to use for that peer.
  */
 static inline int ntb_peer_highest_mw_idx(struct ntb_dev *ntb, int pidx)
 {
     int ret;
 
     ret = ntb_peer_resource_idx(ntb, pidx);
     if (ret < 0)
         return ret;
 
     return ntb_mw_count(ntb, pidx) - ret - 1;
 }
 
 struct ntb_msi_desc {
     u32 addr_offset;
     u32 data;
 };
 
 #ifdef CONFIG_NTB_MSI
 
 int ntb_msi_init(struct ntb_dev *ntb, void (*desc_changed)(void *ctx));
 int ntb_msi_setup_mws(struct ntb_dev *ntb);
 void ntb_msi_clear_mws(struct ntb_dev *ntb);
 int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb, irq_handler_t handler,
                   irq_handler_t thread_fn,
                   const char *name, void *dev_id,
                   struct ntb_msi_desc *msi_desc);
 void ntbm_msi_free_irq(struct ntb_dev *ntb, unsigned int irq, void *dev_id);
 int ntb_msi_peer_trigger(struct ntb_dev *ntb, int peer,
              struct ntb_msi_desc *desc);
 int ntb_msi_peer_addr(struct ntb_dev *ntb, int peer,
               struct ntb_msi_desc *desc,
               phys_addr_t *msi_addr);
 
 #else /* not CONFIG_NTB_MSI */
 
 static inline int ntb_msi_init(struct ntb_dev *ntb,
                    void (*desc_changed)(void *ctx))
 {
     return -EOPNOTSUPP;
 }
 static inline int ntb_msi_setup_mws(struct ntb_dev *ntb)
 {
     return -EOPNOTSUPP;
 }
 static inline void ntb_msi_clear_mws(struct ntb_dev *ntb) {}
 static inline int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb,
                         irq_handler_t handler,
                         irq_handler_t thread_fn,
                         const char *name, void *dev_id,
                         struct ntb_msi_desc *msi_desc)
 {
     return -EOPNOTSUPP;
 }
 static inline void ntbm_msi_free_irq(struct ntb_dev *ntb, unsigned int irq,
                      void *dev_id) {}
 static inline int ntb_msi_peer_trigger(struct ntb_dev *ntb, int peer,
                        struct ntb_msi_desc *desc)
 {
     return -EOPNOTSUPP;
 }
 static inline int ntb_msi_peer_addr(struct ntb_dev *ntb, int peer,
                     struct ntb_msi_desc *desc,
                     phys_addr_t *msi_addr)
 {
     return -EOPNOTSUPP;
 
 }
 
 #endif /* CONFIG_NTB_MSI */
 
 static inline int ntbm_msi_request_irq(struct ntb_dev *ntb,
                        irq_handler_t handler,
                        const char *name, void *dev_id,
                        struct ntb_msi_desc *msi_desc)
 {
     return ntbm_msi_request_threaded_irq(ntb, handler, NULL, name,
                          dev_id, msi_desc);
 }
 
 #endif

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