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authorAllen Hubbe <Allen.Hubbe@emc.com>2015-04-09 10:33:20 -0400
committerJon Mason <jdmason@kudzu.us>2015-07-04 14:04:44 -0400
commita1bd3baeb2f18b2b3d0f98ce5fdaa725149b950b (patch)
treeea7f83ae16bf1369c37f1e5ed585efaa87fc84f2 /include/linux/ntb.h
parentec110bc7cc48d7806c9b65094e6afb19452d458f (diff)
NTB: Add NTB hardware abstraction layer
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@emc.com> Signed-off-by: Jon Mason <jdmason@kudzu.us>
Diffstat (limited to 'include/linux/ntb.h')
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1 files changed, 984 insertions, 0 deletions
diff --git a/include/linux/ntb.h b/include/linux/ntb.h
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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.
+ *
+ * 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@emc.com>
+ */
+
+#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