xref: /linux/include/linux/ntb.h (revision 40286d6379aacfcc053253ef78dc78b09addffda)
1 /*
2  * This file is provided under a dual BSD/GPLv2 license.  When using or
3  *   redistributing this file, you may do so under either license.
4  *
5  *   GPL LICENSE SUMMARY
6  *
7  *   Copyright (C) 2015 EMC Corporation. All Rights Reserved.
8  *   Copyright (C) 2016 T-Platforms. All Rights Reserved.
9  *
10  *   This program is free software; you can redistribute it and/or modify
11  *   it under the terms of version 2 of the GNU General Public License as
12  *   published by the Free Software Foundation.
13  *
14  *   This program is distributed in the hope that it will be useful, but
15  *   WITHOUT ANY WARRANTY; without even the implied warranty of
16  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17  *   General Public License for more details.
18  *
19  *   BSD LICENSE
20  *
21  *   Copyright (C) 2015 EMC Corporation. All Rights Reserved.
22  *   Copyright (C) 2016 T-Platforms. All Rights Reserved.
23  *
24  *   Redistribution and use in source and binary forms, with or without
25  *   modification, are permitted provided that the following conditions
26  *   are met:
27  *
28  *     * Redistributions of source code must retain the above copyright
29  *       notice, this list of conditions and the following disclaimer.
30  *     * Redistributions in binary form must reproduce the above copy
31  *       notice, this list of conditions and the following disclaimer in
32  *       the documentation and/or other materials provided with the
33  *       distribution.
34  *     * Neither the name of Intel Corporation nor the names of its
35  *       contributors may be used to endorse or promote products derived
36  *       from this software without specific prior written permission.
37  *
38  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
39  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
40  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
41  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
42  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
43  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
44  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
45  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
46  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
47  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
48  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
49  *
50  * PCIe NTB Linux driver
51  *
52  * Contact Information:
53  * Allen Hubbe <Allen.Hubbe@emc.com>
54  */
55 
56 #ifndef _NTB_H_
57 #define _NTB_H_
58 
59 #include <linux/completion.h>
60 #include <linux/device.h>
61 #include <linux/interrupt.h>
62 
63 struct ntb_client;
64 struct ntb_dev;
65 struct ntb_msi;
66 struct pci_dev;
67 
68 /**
69  * enum ntb_topo - NTB connection topology
70  * @NTB_TOPO_NONE:	Topology is unknown or invalid.
71  * @NTB_TOPO_PRI:	On primary side of local ntb.
72  * @NTB_TOPO_SEC:	On secondary side of remote ntb.
73  * @NTB_TOPO_B2B_USD:	On primary side of local ntb upstream of remote ntb.
74  * @NTB_TOPO_B2B_DSD:	On primary side of local ntb downstream of remote ntb.
75  * @NTB_TOPO_SWITCH:	Connected via a switch which supports ntb.
76  * @NTB_TOPO_CROSSLINK: Connected via two symmetric switchecs
77  */
78 enum ntb_topo {
79 	NTB_TOPO_NONE = -1,
80 	NTB_TOPO_PRI,
81 	NTB_TOPO_SEC,
82 	NTB_TOPO_B2B_USD,
83 	NTB_TOPO_B2B_DSD,
84 	NTB_TOPO_SWITCH,
85 	NTB_TOPO_CROSSLINK,
86 };
87 
88 static inline int ntb_topo_is_b2b(enum ntb_topo topo)
89 {
90 	switch ((int)topo) {
91 	case NTB_TOPO_B2B_USD:
92 	case NTB_TOPO_B2B_DSD:
93 		return 1;
94 	}
95 	return 0;
96 }
97 
98 static inline char *ntb_topo_string(enum ntb_topo topo)
99 {
100 	switch (topo) {
101 	case NTB_TOPO_NONE:		return "NTB_TOPO_NONE";
102 	case NTB_TOPO_PRI:		return "NTB_TOPO_PRI";
103 	case NTB_TOPO_SEC:		return "NTB_TOPO_SEC";
104 	case NTB_TOPO_B2B_USD:		return "NTB_TOPO_B2B_USD";
105 	case NTB_TOPO_B2B_DSD:		return "NTB_TOPO_B2B_DSD";
106 	case NTB_TOPO_SWITCH:		return "NTB_TOPO_SWITCH";
107 	case NTB_TOPO_CROSSLINK:	return "NTB_TOPO_CROSSLINK";
108 	}
109 	return "NTB_TOPO_INVALID";
110 }
111 
112 /**
113  * enum ntb_speed - NTB link training speed
114  * @NTB_SPEED_AUTO:	Request the max supported speed.
115  * @NTB_SPEED_NONE:	Link is not trained to any speed.
116  * @NTB_SPEED_GEN1:	Link is trained to gen1 speed.
117  * @NTB_SPEED_GEN2:	Link is trained to gen2 speed.
118  * @NTB_SPEED_GEN3:	Link is trained to gen3 speed.
119  * @NTB_SPEED_GEN4:	Link is trained to gen4 speed.
120  */
121 enum ntb_speed {
122 	NTB_SPEED_AUTO = -1,
123 	NTB_SPEED_NONE = 0,
124 	NTB_SPEED_GEN1 = 1,
125 	NTB_SPEED_GEN2 = 2,
126 	NTB_SPEED_GEN3 = 3,
127 	NTB_SPEED_GEN4 = 4
128 };
129 
130 /**
131  * enum ntb_width - NTB link training width
132  * @NTB_WIDTH_AUTO:	Request the max supported width.
133  * @NTB_WIDTH_NONE:	Link is not trained to any width.
134  * @NTB_WIDTH_1:	Link is trained to 1 lane width.
135  * @NTB_WIDTH_2:	Link is trained to 2 lane width.
136  * @NTB_WIDTH_4:	Link is trained to 4 lane width.
137  * @NTB_WIDTH_8:	Link is trained to 8 lane width.
138  * @NTB_WIDTH_12:	Link is trained to 12 lane width.
139  * @NTB_WIDTH_16:	Link is trained to 16 lane width.
140  * @NTB_WIDTH_32:	Link is trained to 32 lane width.
141  */
142 enum ntb_width {
143 	NTB_WIDTH_AUTO = -1,
144 	NTB_WIDTH_NONE = 0,
145 	NTB_WIDTH_1 = 1,
146 	NTB_WIDTH_2 = 2,
147 	NTB_WIDTH_4 = 4,
148 	NTB_WIDTH_8 = 8,
149 	NTB_WIDTH_12 = 12,
150 	NTB_WIDTH_16 = 16,
151 	NTB_WIDTH_32 = 32,
152 };
153 
154 /**
155  * enum ntb_default_port - NTB default port number
156  * @NTB_PORT_PRI_USD:	Default port of the NTB_TOPO_PRI/NTB_TOPO_B2B_USD
157  *			topologies
158  * @NTB_PORT_SEC_DSD:	Default port of the NTB_TOPO_SEC/NTB_TOPO_B2B_DSD
159  *			topologies
160  */
161 enum ntb_default_port {
162 	NTB_PORT_PRI_USD,
163 	NTB_PORT_SEC_DSD
164 };
165 #define NTB_DEF_PEER_CNT	(1)
166 #define NTB_DEF_PEER_IDX	(0)
167 
168 /**
169  * struct ntb_client_ops - ntb client operations
170  * @probe:		Notify client of a new device.
171  * @remove:		Notify client to remove a device.
172  */
173 struct ntb_client_ops {
174 	int (*probe)(struct ntb_client *client, struct ntb_dev *ntb);
175 	void (*remove)(struct ntb_client *client, struct ntb_dev *ntb);
176 };
177 
178 static inline int ntb_client_ops_is_valid(const struct ntb_client_ops *ops)
179 {
180 	/* commented callbacks are not required: */
181 	return
182 		ops->probe			&&
183 		ops->remove			&&
184 		1;
185 }
186 
187 /**
188  * struct ntb_ctx_ops - ntb driver context operations
189  * @link_event:		See ntb_link_event().
190  * @db_event:		See ntb_db_event().
191  * @msg_event:		See ntb_msg_event().
192  */
193 struct ntb_ctx_ops {
194 	void (*link_event)(void *ctx);
195 	void (*db_event)(void *ctx, int db_vector);
196 	void (*msg_event)(void *ctx);
197 };
198 
199 static inline int ntb_ctx_ops_is_valid(const struct ntb_ctx_ops *ops)
200 {
201 	/* commented callbacks are not required: */
202 	return
203 		/* ops->link_event		&& */
204 		/* ops->db_event		&& */
205 		/* ops->msg_event		&& */
206 		1;
207 }
208 
209 /**
210  * struct ntb_dev_ops - ntb device operations
211  * @port_number:	See ntb_port_number().
212  * @peer_port_count:	See ntb_peer_port_count().
213  * @peer_port_number:	See ntb_peer_port_number().
214  * @peer_port_idx:	See ntb_peer_port_idx().
215  * @link_is_up:		See ntb_link_is_up().
216  * @link_enable:	See ntb_link_enable().
217  * @link_disable:	See ntb_link_disable().
218  * @mw_count:		See ntb_mw_count().
219  * @mw_get_align:	See ntb_mw_get_align().
220  * @mw_set_trans:	See ntb_mw_set_trans().
221  * @mw_clear_trans:	See ntb_mw_clear_trans().
222  * @peer_mw_count:	See ntb_peer_mw_count().
223  * @peer_mw_get_addr:	See ntb_peer_mw_get_addr().
224  * @peer_mw_set_trans:	See ntb_peer_mw_set_trans().
225  * @peer_mw_clear_trans:See ntb_peer_mw_clear_trans().
226  * @db_is_unsafe:	See ntb_db_is_unsafe().
227  * @db_valid_mask:	See ntb_db_valid_mask().
228  * @db_vector_count:	See ntb_db_vector_count().
229  * @db_vector_mask:	See ntb_db_vector_mask().
230  * @db_read:		See ntb_db_read().
231  * @db_set:		See ntb_db_set().
232  * @db_clear:		See ntb_db_clear().
233  * @db_read_mask:	See ntb_db_read_mask().
234  * @db_set_mask:	See ntb_db_set_mask().
235  * @db_clear_mask:	See ntb_db_clear_mask().
236  * @peer_db_addr:	See ntb_peer_db_addr().
237  * @peer_db_read:	See ntb_peer_db_read().
238  * @peer_db_set:	See ntb_peer_db_set().
239  * @peer_db_clear:	See ntb_peer_db_clear().
240  * @peer_db_read_mask:	See ntb_peer_db_read_mask().
241  * @peer_db_set_mask:	See ntb_peer_db_set_mask().
242  * @peer_db_clear_mask:	See ntb_peer_db_clear_mask().
243  * @spad_is_unsafe:	See ntb_spad_is_unsafe().
244  * @spad_count:		See ntb_spad_count().
245  * @spad_read:		See ntb_spad_read().
246  * @spad_write:		See ntb_spad_write().
247  * @peer_spad_addr:	See ntb_peer_spad_addr().
248  * @peer_spad_read:	See ntb_peer_spad_read().
249  * @peer_spad_write:	See ntb_peer_spad_write().
250  * @msg_count:		See ntb_msg_count().
251  * @msg_inbits:		See ntb_msg_inbits().
252  * @msg_outbits:	See ntb_msg_outbits().
253  * @msg_read_sts:	See ntb_msg_read_sts().
254  * @msg_clear_sts:	See ntb_msg_clear_sts().
255  * @msg_set_mask:	See ntb_msg_set_mask().
256  * @msg_clear_mask:	See ntb_msg_clear_mask().
257  * @msg_read:		See ntb_msg_read().
258  * @peer_msg_write:	See ntb_peer_msg_write().
259  * @get_dma_dev:	See ntb_get_dma_dev().
260  */
261 struct ntb_dev_ops {
262 	int (*port_number)(struct ntb_dev *ntb);
263 	int (*peer_port_count)(struct ntb_dev *ntb);
264 	int (*peer_port_number)(struct ntb_dev *ntb, int pidx);
265 	int (*peer_port_idx)(struct ntb_dev *ntb, int port);
266 
267 	u64 (*link_is_up)(struct ntb_dev *ntb,
268 			  enum ntb_speed *speed, enum ntb_width *width);
269 	int (*link_enable)(struct ntb_dev *ntb,
270 			   enum ntb_speed max_speed, enum ntb_width max_width);
271 	int (*link_disable)(struct ntb_dev *ntb);
272 
273 	int (*mw_count)(struct ntb_dev *ntb, int pidx);
274 	int (*mw_get_align)(struct ntb_dev *ntb, int pidx, int widx,
275 			    resource_size_t *addr_align,
276 			    resource_size_t *size_align,
277 			    resource_size_t *size_max);
278 	int (*mw_set_trans)(struct ntb_dev *ntb, int pidx, int widx,
279 			    dma_addr_t addr, resource_size_t size);
280 	int (*mw_clear_trans)(struct ntb_dev *ntb, int pidx, int widx);
281 	int (*peer_mw_count)(struct ntb_dev *ntb);
282 	int (*peer_mw_get_addr)(struct ntb_dev *ntb, int widx,
283 				phys_addr_t *base, resource_size_t *size);
284 	int (*peer_mw_set_trans)(struct ntb_dev *ntb, int pidx, int widx,
285 				 u64 addr, resource_size_t size);
286 	int (*peer_mw_clear_trans)(struct ntb_dev *ntb, int pidx, int widx);
287 
288 	int (*db_is_unsafe)(struct ntb_dev *ntb);
289 	u64 (*db_valid_mask)(struct ntb_dev *ntb);
290 	int (*db_vector_count)(struct ntb_dev *ntb);
291 	u64 (*db_vector_mask)(struct ntb_dev *ntb, int db_vector);
292 
293 	u64 (*db_read)(struct ntb_dev *ntb);
294 	int (*db_set)(struct ntb_dev *ntb, u64 db_bits);
295 	int (*db_clear)(struct ntb_dev *ntb, u64 db_bits);
296 
297 	u64 (*db_read_mask)(struct ntb_dev *ntb);
298 	int (*db_set_mask)(struct ntb_dev *ntb, u64 db_bits);
299 	int (*db_clear_mask)(struct ntb_dev *ntb, u64 db_bits);
300 
301 	int (*peer_db_addr)(struct ntb_dev *ntb,
302 			    phys_addr_t *db_addr, resource_size_t *db_size,
303 				u64 *db_data, int db_bit);
304 	u64 (*peer_db_read)(struct ntb_dev *ntb);
305 	int (*peer_db_set)(struct ntb_dev *ntb, u64 db_bits);
306 	int (*peer_db_clear)(struct ntb_dev *ntb, u64 db_bits);
307 
308 	u64 (*peer_db_read_mask)(struct ntb_dev *ntb);
309 	int (*peer_db_set_mask)(struct ntb_dev *ntb, u64 db_bits);
310 	int (*peer_db_clear_mask)(struct ntb_dev *ntb, u64 db_bits);
311 
312 	int (*spad_is_unsafe)(struct ntb_dev *ntb);
313 	int (*spad_count)(struct ntb_dev *ntb);
314 
315 	u32 (*spad_read)(struct ntb_dev *ntb, int sidx);
316 	int (*spad_write)(struct ntb_dev *ntb, int sidx, u32 val);
317 
318 	int (*peer_spad_addr)(struct ntb_dev *ntb, int pidx, int sidx,
319 			      phys_addr_t *spad_addr);
320 	u32 (*peer_spad_read)(struct ntb_dev *ntb, int pidx, int sidx);
321 	int (*peer_spad_write)(struct ntb_dev *ntb, int pidx, int sidx,
322 			       u32 val);
323 
324 	int (*msg_count)(struct ntb_dev *ntb);
325 	u64 (*msg_inbits)(struct ntb_dev *ntb);
326 	u64 (*msg_outbits)(struct ntb_dev *ntb);
327 	u64 (*msg_read_sts)(struct ntb_dev *ntb);
328 	int (*msg_clear_sts)(struct ntb_dev *ntb, u64 sts_bits);
329 	int (*msg_set_mask)(struct ntb_dev *ntb, u64 mask_bits);
330 	int (*msg_clear_mask)(struct ntb_dev *ntb, u64 mask_bits);
331 	u32 (*msg_read)(struct ntb_dev *ntb, int *pidx, int midx);
332 	int (*peer_msg_write)(struct ntb_dev *ntb, int pidx, int midx, u32 msg);
333 	struct device *(*get_dma_dev)(struct ntb_dev *ntb);
334 };
335 
336 static inline int ntb_dev_ops_is_valid(const struct ntb_dev_ops *ops)
337 {
338 	/* commented callbacks are not required: */
339 	return
340 		/* Port operations are required for multiport devices */
341 		!ops->peer_port_count == !ops->port_number	&&
342 		!ops->peer_port_number == !ops->port_number	&&
343 		!ops->peer_port_idx == !ops->port_number	&&
344 
345 		/* Link operations are required */
346 		ops->link_is_up				&&
347 		ops->link_enable			&&
348 		ops->link_disable			&&
349 
350 		/* One or both MW interfaces should be developed */
351 		ops->mw_count				&&
352 		ops->mw_get_align			&&
353 		(ops->mw_set_trans			||
354 		 ops->peer_mw_set_trans)		&&
355 		/* ops->mw_clear_trans			&& */
356 		ops->peer_mw_count			&&
357 		ops->peer_mw_get_addr			&&
358 		/* ops->peer_mw_clear_trans		&& */
359 
360 		/* Doorbell operations are mostly required */
361 		/* ops->db_is_unsafe			&& */
362 		ops->db_valid_mask			&&
363 		/* both set, or both unset */
364 		(!ops->db_vector_count == !ops->db_vector_mask)	&&
365 		ops->db_read				&&
366 		/* ops->db_set				&& */
367 		ops->db_clear				&&
368 		/* ops->db_read_mask			&& */
369 		ops->db_set_mask			&&
370 		ops->db_clear_mask			&&
371 		/* ops->peer_db_addr			&& */
372 		/* ops->peer_db_read			&& */
373 		ops->peer_db_set			&&
374 		/* ops->peer_db_clear			&& */
375 		/* ops->peer_db_read_mask		&& */
376 		/* ops->peer_db_set_mask		&& */
377 		/* ops->peer_db_clear_mask		&& */
378 
379 		/* Scrachpads interface is optional */
380 		/* !ops->spad_is_unsafe == !ops->spad_count	&& */
381 		!ops->spad_read == !ops->spad_count		&&
382 		!ops->spad_write == !ops->spad_count		&&
383 		/* !ops->peer_spad_addr == !ops->spad_count	&& */
384 		/* !ops->peer_spad_read == !ops->spad_count	&& */
385 		!ops->peer_spad_write == !ops->spad_count	&&
386 
387 		/* Messaging interface is optional */
388 		!ops->msg_inbits == !ops->msg_count		&&
389 		!ops->msg_outbits == !ops->msg_count		&&
390 		!ops->msg_read_sts == !ops->msg_count		&&
391 		!ops->msg_clear_sts == !ops->msg_count		&&
392 		/* !ops->msg_set_mask == !ops->msg_count	&& */
393 		/* !ops->msg_clear_mask == !ops->msg_count	&& */
394 		!ops->msg_read == !ops->msg_count		&&
395 		!ops->peer_msg_write == !ops->msg_count		&&
396 
397 		/* ops->get_dma_dev is optional */
398 		1;
399 }
400 
401 /**
402  * struct ntb_client - client interested in ntb devices
403  * @drv:		Linux driver object.
404  * @ops:		See &ntb_client_ops.
405  */
406 struct ntb_client {
407 	struct device_driver		drv;
408 	const struct ntb_client_ops	ops;
409 };
410 #define drv_ntb_client(__drv) container_of((__drv), struct ntb_client, drv)
411 
412 /**
413  * struct ntb_dev - ntb device
414  * @dev:		Linux device object.
415  * @pdev:		PCI device entry of the ntb.
416  * @topo:		Detected topology of the ntb.
417  * @ops:		See &ntb_dev_ops.
418  * @ctx:		See &ntb_ctx_ops.
419  * @ctx_ops:		See &ntb_ctx_ops.
420  */
421 struct ntb_dev {
422 	struct device			dev;
423 	struct pci_dev			*pdev;
424 	enum ntb_topo			topo;
425 	const struct ntb_dev_ops	*ops;
426 	void				*ctx;
427 	const struct ntb_ctx_ops	*ctx_ops;
428 
429 	/* private: */
430 
431 	/* synchronize setting, clearing, and calling ctx_ops */
432 	spinlock_t			ctx_lock;
433 	/* block unregister until device is fully released */
434 	struct completion		released;
435 
436 #ifdef CONFIG_NTB_MSI
437 	struct ntb_msi *msi;
438 #endif
439 };
440 #define dev_ntb(__dev) container_of((__dev), struct ntb_dev, dev)
441 
442 /**
443  * ntb_register_client() - register a client for interest in ntb devices
444  * @client:	Client context.
445  *
446  * The client will be added to the list of clients interested in ntb devices.
447  * The client will be notified of any ntb devices that are not already
448  * associated with a client, or if ntb devices are registered later.
449  *
450  * Return: Zero if the client is registered, otherwise an error number.
451  */
452 #define ntb_register_client(client) \
453 	__ntb_register_client((client), THIS_MODULE, KBUILD_MODNAME)
454 
455 int __ntb_register_client(struct ntb_client *client, struct module *mod,
456 			  const char *mod_name);
457 
458 /**
459  * ntb_unregister_client() - unregister a client for interest in ntb devices
460  * @client:	Client context.
461  *
462  * The client will be removed from the list of clients interested in ntb
463  * devices.  If any ntb devices are associated with the client, the client will
464  * be notified to remove those devices.
465  */
466 void ntb_unregister_client(struct ntb_client *client);
467 
468 #define module_ntb_client(__ntb_client) \
469 	module_driver(__ntb_client, ntb_register_client, \
470 			ntb_unregister_client)
471 
472 /**
473  * ntb_register_device() - register a ntb device
474  * @ntb:	NTB device context.
475  *
476  * The device will be added to the list of ntb devices.  If any clients are
477  * interested in ntb devices, each client will be notified of the ntb device,
478  * until at most one client accepts the device.
479  *
480  * Return: Zero if the device is registered, otherwise an error number.
481  */
482 int ntb_register_device(struct ntb_dev *ntb);
483 
484 /**
485  * ntb_unregister_device() - unregister a ntb device
486  * @ntb:	NTB device context.
487  *
488  * The device will be removed from the list of ntb devices.  If the ntb device
489  * is associated with a client, the client will be notified to remove the
490  * device.
491  */
492 void ntb_unregister_device(struct ntb_dev *ntb);
493 
494 /**
495  * ntb_set_ctx() - associate a driver context with an ntb device
496  * @ntb:	NTB device context.
497  * @ctx:	Driver context.
498  * @ctx_ops:	Driver context operations.
499  *
500  * Associate a driver context and operations with a ntb device.  The context is
501  * provided by the client driver, and the driver may associate a different
502  * context with each ntb device.
503  *
504  * Return: Zero if the context is associated, otherwise an error number.
505  */
506 int ntb_set_ctx(struct ntb_dev *ntb, void *ctx,
507 		const struct ntb_ctx_ops *ctx_ops);
508 
509 /**
510  * ntb_clear_ctx() - disassociate any driver context from an ntb device
511  * @ntb:	NTB device context.
512  *
513  * Clear any association that may exist between a driver context and the ntb
514  * device.
515  */
516 void ntb_clear_ctx(struct ntb_dev *ntb);
517 
518 /**
519  * ntb_link_event() - notify driver context of a change in link status
520  * @ntb:	NTB device context.
521  *
522  * Notify the driver context that the link status may have changed.  The driver
523  * should call ntb_link_is_up() to get the current status.
524  */
525 void ntb_link_event(struct ntb_dev *ntb);
526 
527 /**
528  * ntb_db_event() - notify driver context of a doorbell event
529  * @ntb:	NTB device context.
530  * @vector:	Interrupt vector number.
531  *
532  * Notify the driver context of a doorbell event.  If hardware supports
533  * multiple interrupt vectors for doorbells, the vector number indicates which
534  * vector received the interrupt.  The vector number is relative to the first
535  * vector used for doorbells, starting at zero, and must be less than
536  * ntb_db_vector_count().  The driver may call ntb_db_read() to check which
537  * doorbell bits need service, and ntb_db_vector_mask() to determine which of
538  * those bits are associated with the vector number.
539  */
540 void ntb_db_event(struct ntb_dev *ntb, int vector);
541 
542 /**
543  * ntb_msg_event() - notify driver context of a message event
544  * @ntb:	NTB device context.
545  *
546  * Notify the driver context of a message event.  If hardware supports
547  * message registers, this event indicates, that a new message arrived in
548  * some incoming message register or last sent message couldn't be delivered.
549  * The events can be masked/unmasked by the methods ntb_msg_set_mask() and
550  * ntb_msg_clear_mask().
551  */
552 void ntb_msg_event(struct ntb_dev *ntb);
553 
554 /**
555  * ntb_default_port_number() - get the default local port number
556  * @ntb:	NTB device context.
557  *
558  * If hardware driver doesn't specify port_number() callback method, the NTB
559  * is considered with just two ports. So this method returns default local
560  * port number in compliance with topology.
561  *
562  * NOTE Don't call this method directly. The ntb_port_number() function should
563  * be used instead.
564  *
565  * Return: the default local port number
566  */
567 int ntb_default_port_number(struct ntb_dev *ntb);
568 
569 /**
570  * ntb_default_port_count() - get the default number of peer device ports
571  * @ntb:	NTB device context.
572  *
573  * By default hardware driver supports just one peer device.
574  *
575  * NOTE Don't call this method directly. The ntb_peer_port_count() function
576  * should be used instead.
577  *
578  * Return: the default number of peer ports
579  */
580 int ntb_default_peer_port_count(struct ntb_dev *ntb);
581 
582 /**
583  * ntb_default_peer_port_number() - get the default peer port by given index
584  * @ntb:	NTB device context.
585  * @idx:	Peer port index (should not differ from zero).
586  *
587  * By default hardware driver supports just one peer device, so this method
588  * shall return the corresponding value from enum ntb_default_port.
589  *
590  * NOTE Don't call this method directly. The ntb_peer_port_number() function
591  * should be used instead.
592  *
593  * Return: the peer device port or negative value indicating an error
594  */
595 int ntb_default_peer_port_number(struct ntb_dev *ntb, int pidx);
596 
597 /**
598  * ntb_default_peer_port_idx() - get the default peer device port index by
599  *				 given port number
600  * @ntb:	NTB device context.
601  * @port:	Peer port number (should be one of enum ntb_default_port).
602  *
603  * By default hardware driver supports just one peer device, so while
604  * specified port-argument indicates peer port from enum ntb_default_port,
605  * the return value shall be zero.
606  *
607  * NOTE Don't call this method directly. The ntb_peer_port_idx() function
608  * should be used instead.
609  *
610  * Return: the peer port index or negative value indicating an error
611  */
612 int ntb_default_peer_port_idx(struct ntb_dev *ntb, int port);
613 
614 /**
615  * ntb_port_number() - get the local port number
616  * @ntb:	NTB device context.
617  *
618  * Hardware must support at least simple two-ports ntb connection
619  *
620  * Return: the local port number
621  */
622 static inline int ntb_port_number(struct ntb_dev *ntb)
623 {
624 	if (!ntb->ops->port_number)
625 		return ntb_default_port_number(ntb);
626 
627 	return ntb->ops->port_number(ntb);
628 }
629 /**
630  * ntb_peer_port_count() - get the number of peer device ports
631  * @ntb:	NTB device context.
632  *
633  * Hardware may support an access to memory of several remote domains
634  * over multi-port NTB devices. This method returns the number of peers,
635  * local device can have shared memory with.
636  *
637  * Return: the number of peer ports
638  */
639 static inline int ntb_peer_port_count(struct ntb_dev *ntb)
640 {
641 	if (!ntb->ops->peer_port_count)
642 		return ntb_default_peer_port_count(ntb);
643 
644 	return ntb->ops->peer_port_count(ntb);
645 }
646 
647 /**
648  * ntb_peer_port_number() - get the peer port by given index
649  * @ntb:	NTB device context.
650  * @pidx:	Peer port index.
651  *
652  * Peer ports are continuously enumerated by NTB API logic, so this method
653  * lets to retrieve port real number by its index.
654  *
655  * Return: the peer device port or negative value indicating an error
656  */
657 static inline int ntb_peer_port_number(struct ntb_dev *ntb, int pidx)
658 {
659 	if (!ntb->ops->peer_port_number)
660 		return ntb_default_peer_port_number(ntb, pidx);
661 
662 	return ntb->ops->peer_port_number(ntb, pidx);
663 }
664 
665 /**
666  * ntb_logical_port_number() - get the logical port number of the local port
667  * @ntb:	NTB device context.
668  *
669  * The Logical Port Number is defined to be a unique number for each
670  * port starting from zero through to the number of ports minus one.
671  * This is in contrast to the Port Number where each port can be assigned
672  * any unique physical number by the hardware.
673  *
674  * The logical port number is useful for calculating the resource indexes
675  * used by peers.
676  *
677  * Return: the logical port number or negative value indicating an error
678  */
679 static inline int ntb_logical_port_number(struct ntb_dev *ntb)
680 {
681 	int lport = ntb_port_number(ntb);
682 	int pidx;
683 
684 	if (lport < 0)
685 		return lport;
686 
687 	for (pidx = 0; pidx < ntb_peer_port_count(ntb); pidx++)
688 		if (lport <= ntb_peer_port_number(ntb, pidx))
689 			return pidx;
690 
691 	return pidx;
692 }
693 
694 /**
695  * ntb_peer_logical_port_number() - get the logical peer port by given index
696  * @ntb:	NTB device context.
697  * @pidx:	Peer port index.
698  *
699  * The Logical Port Number is defined to be a unique number for each
700  * port starting from zero through to the number of ports minus one.
701  * This is in contrast to the Port Number where each port can be assigned
702  * any unique physical number by the hardware.
703  *
704  * The logical port number is useful for calculating the resource indexes
705  * used by peers.
706  *
707  * Return: the peer's logical port number or negative value indicating an error
708  */
709 static inline int ntb_peer_logical_port_number(struct ntb_dev *ntb, int pidx)
710 {
711 	if (ntb_peer_port_number(ntb, pidx) < ntb_port_number(ntb))
712 		return pidx;
713 	else
714 		return pidx + 1;
715 }
716 
717 /**
718  * ntb_peer_port_idx() - get the peer device port index by given port number
719  * @ntb:	NTB device context.
720  * @port:	Peer port number.
721  *
722  * Inverse operation of ntb_peer_port_number(), so one can get port index
723  * by specified port number.
724  *
725  * Return: the peer port index or negative value indicating an error
726  */
727 static inline int ntb_peer_port_idx(struct ntb_dev *ntb, int port)
728 {
729 	if (!ntb->ops->peer_port_idx)
730 		return ntb_default_peer_port_idx(ntb, port);
731 
732 	return ntb->ops->peer_port_idx(ntb, port);
733 }
734 
735 /**
736  * ntb_link_is_up() - get the current ntb link state
737  * @ntb:	NTB device context.
738  * @speed:	OUT - The link speed expressed as PCIe generation number.
739  * @width:	OUT - The link width expressed as the number of PCIe lanes.
740  *
741  * Get the current state of the ntb link.  It is recommended to query the link
742  * state once after every link event.  It is safe to query the link state in
743  * the context of the link event callback.
744  *
745  * Return: bitfield of indexed ports link state: bit is set/cleared if the
746  *         link is up/down respectively.
747  */
748 static inline u64 ntb_link_is_up(struct ntb_dev *ntb,
749 				 enum ntb_speed *speed, enum ntb_width *width)
750 {
751 	return ntb->ops->link_is_up(ntb, speed, width);
752 }
753 
754 /**
755  * ntb_link_enable() - enable the local port ntb connection
756  * @ntb:	NTB device context.
757  * @max_speed:	The maximum link speed expressed as PCIe generation number.
758  * @max_width:	The maximum link width expressed as the number of PCIe lanes.
759  *
760  * Enable the NTB/PCIe link on the local or remote (for bridge-to-bridge
761  * topology) side of the bridge. If it's supported the ntb device should train
762  * the link to its maximum speed and width, or the requested speed and width,
763  * whichever is smaller. Some hardware doesn't support PCIe link training, so
764  * the last two arguments will be ignored then.
765  *
766  * Return: Zero on success, otherwise an error number.
767  */
768 static inline int ntb_link_enable(struct ntb_dev *ntb,
769 				  enum ntb_speed max_speed,
770 				  enum ntb_width max_width)
771 {
772 	return ntb->ops->link_enable(ntb, max_speed, max_width);
773 }
774 
775 /**
776  * ntb_link_disable() - disable the local port ntb connection
777  * @ntb:	NTB device context.
778  *
779  * Disable the link on the local or remote (for b2b topology) of the ntb.
780  * The ntb device should disable the link.  Returning from this call must
781  * indicate that a barrier has passed, though with no more writes may pass in
782  * either direction across the link, except if this call returns an error
783  * number.
784  *
785  * Return: Zero on success, otherwise an error number.
786  */
787 static inline int ntb_link_disable(struct ntb_dev *ntb)
788 {
789 	return ntb->ops->link_disable(ntb);
790 }
791 
792 /**
793  * ntb_mw_count() - get the number of inbound memory windows, which could
794  *                  be created for a specified peer device
795  * @ntb:	NTB device context.
796  * @pidx:	Port index of peer device.
797  *
798  * Hardware and topology may support a different number of memory windows.
799  * Moreover different peer devices can support different number of memory
800  * windows. Simply speaking this method returns the number of possible inbound
801  * memory windows to share with specified peer device. Note: this may return
802  * zero if the link is not up yet.
803  *
804  * Return: the number of memory windows.
805  */
806 static inline int ntb_mw_count(struct ntb_dev *ntb, int pidx)
807 {
808 	return ntb->ops->mw_count(ntb, pidx);
809 }
810 
811 /**
812  * ntb_mw_get_align() - get the restriction parameters of inbound memory window
813  * @ntb:	NTB device context.
814  * @pidx:	Port index of peer device.
815  * @widx:	Memory window index.
816  * @addr_align:	OUT - the base alignment for translating the memory window
817  * @size_align:	OUT - the size alignment for translating the memory window
818  * @size_max:	OUT - the maximum size of the memory window
819  *
820  * Get the alignments of an inbound memory window with specified index.
821  * NULL may be given for any output parameter if the value is not needed.
822  * The alignment and size parameters may be used for allocation of proper
823  * shared memory. Note: this must only be called when the link is up.
824  *
825  * Return: Zero on success, otherwise a negative error number.
826  */
827 static inline int ntb_mw_get_align(struct ntb_dev *ntb, int pidx, int widx,
828 				   resource_size_t *addr_align,
829 				   resource_size_t *size_align,
830 				   resource_size_t *size_max)
831 {
832 	if (!(ntb_link_is_up(ntb, NULL, NULL) & BIT_ULL(pidx)))
833 		return -ENOTCONN;
834 
835 	return ntb->ops->mw_get_align(ntb, pidx, widx, addr_align, size_align,
836 				      size_max);
837 }
838 
839 /**
840  * ntb_mw_set_trans() - set the translation of an inbound memory window
841  * @ntb:	NTB device context.
842  * @pidx:	Port index of peer device.
843  * @widx:	Memory window index.
844  * @addr:	The dma address of local memory to expose to the peer.
845  * @size:	The size of the local memory to expose to the peer.
846  *
847  * Set the translation of a memory window.  The peer may access local memory
848  * through the window starting at the address, up to the size.  The address
849  * and size must be aligned in compliance with restrictions of
850  * ntb_mw_get_align(). The region size should not exceed the size_max parameter
851  * of that method.
852  *
853  * This method may not be implemented due to the hardware specific memory
854  * windows interface.
855  *
856  * Return: Zero on success, otherwise an error number.
857  */
858 static inline int ntb_mw_set_trans(struct ntb_dev *ntb, int pidx, int widx,
859 				   dma_addr_t addr, resource_size_t size)
860 {
861 	if (!ntb->ops->mw_set_trans)
862 		return 0;
863 
864 	return ntb->ops->mw_set_trans(ntb, pidx, widx, addr, size);
865 }
866 
867 /**
868  * ntb_mw_clear_trans() - clear the translation address of an inbound memory
869  *                        window
870  * @ntb:	NTB device context.
871  * @pidx:	Port index of peer device.
872  * @widx:	Memory window index.
873  *
874  * Clear the translation of an inbound memory window.  The peer may no longer
875  * access local memory through the window.
876  *
877  * Return: Zero on success, otherwise an error number.
878  */
879 static inline int ntb_mw_clear_trans(struct ntb_dev *ntb, int pidx, int widx)
880 {
881 	if (!ntb->ops->mw_clear_trans)
882 		return ntb_mw_set_trans(ntb, pidx, widx, 0, 0);
883 
884 	return ntb->ops->mw_clear_trans(ntb, pidx, widx);
885 }
886 
887 /**
888  * ntb_peer_mw_count() - get the number of outbound memory windows, which could
889  *                       be mapped to access a shared memory
890  * @ntb:	NTB device context.
891  *
892  * Hardware and topology may support a different number of memory windows.
893  * This method returns the number of outbound memory windows supported by
894  * local device.
895  *
896  * Return: the number of memory windows.
897  */
898 static inline int ntb_peer_mw_count(struct ntb_dev *ntb)
899 {
900 	return ntb->ops->peer_mw_count(ntb);
901 }
902 
903 /**
904  * ntb_peer_mw_get_addr() - get map address of an outbound memory window
905  * @ntb:	NTB device context.
906  * @widx:	Memory window index (within ntb_peer_mw_count() return value).
907  * @base:	OUT - the base address of mapping region.
908  * @size:	OUT - the size of mapping region.
909  *
910  * Get base and size of memory region to map.  NULL may be given for any output
911  * parameter if the value is not needed.  The base and size may be used for
912  * mapping the memory window, to access the peer memory.
913  *
914  * Return: Zero on success, otherwise a negative error number.
915  */
916 static inline int ntb_peer_mw_get_addr(struct ntb_dev *ntb, int widx,
917 				      phys_addr_t *base, resource_size_t *size)
918 {
919 	return ntb->ops->peer_mw_get_addr(ntb, widx, base, size);
920 }
921 
922 /**
923  * ntb_peer_mw_set_trans() - set a translation address of a memory window
924  *                           retrieved from a peer device
925  * @ntb:	NTB device context.
926  * @pidx:	Port index of peer device the translation address received from.
927  * @widx:	Memory window index.
928  * @addr:	The dma address of the shared memory to access.
929  * @size:	The size of the shared memory to access.
930  *
931  * Set the translation of an outbound memory window.  The local device may
932  * access shared memory allocated by a peer device sent the address.
933  *
934  * This method may not be implemented due to the hardware specific memory
935  * windows interface, so a translation address can be only set on the side,
936  * where shared memory (inbound memory windows) is allocated.
937  *
938  * Return: Zero on success, otherwise an error number.
939  */
940 static inline int ntb_peer_mw_set_trans(struct ntb_dev *ntb, int pidx, int widx,
941 					u64 addr, resource_size_t size)
942 {
943 	if (!ntb->ops->peer_mw_set_trans)
944 		return 0;
945 
946 	return ntb->ops->peer_mw_set_trans(ntb, pidx, widx, addr, size);
947 }
948 
949 /**
950  * ntb_peer_mw_clear_trans() - clear the translation address of an outbound
951  *                             memory window
952  * @ntb:	NTB device context.
953  * @pidx:	Port index of peer device.
954  * @widx:	Memory window index.
955  *
956  * Clear the translation of a outbound memory window.  The local device may no
957  * longer access a shared memory through the window.
958  *
959  * This method may not be implemented due to the hardware specific memory
960  * windows interface.
961  *
962  * Return: Zero on success, otherwise an error number.
963  */
964 static inline int ntb_peer_mw_clear_trans(struct ntb_dev *ntb, int pidx,
965 					  int widx)
966 {
967 	if (!ntb->ops->peer_mw_clear_trans)
968 		return ntb_peer_mw_set_trans(ntb, pidx, widx, 0, 0);
969 
970 	return ntb->ops->peer_mw_clear_trans(ntb, pidx, widx);
971 }
972 
973 /**
974  * ntb_db_is_unsafe() - check if it is safe to use hardware doorbell
975  * @ntb:	NTB device context.
976  *
977  * It is possible for some ntb hardware to be affected by errata.  Hardware
978  * drivers can advise clients to avoid using doorbells.  Clients may ignore
979  * this advice, though caution is recommended.
980  *
981  * Return: Zero if it is safe to use doorbells, or One if it is not safe.
982  */
983 static inline int ntb_db_is_unsafe(struct ntb_dev *ntb)
984 {
985 	if (!ntb->ops->db_is_unsafe)
986 		return 0;
987 
988 	return ntb->ops->db_is_unsafe(ntb);
989 }
990 
991 /**
992  * ntb_db_valid_mask() - get a mask of doorbell bits supported by the ntb
993  * @ntb:	NTB device context.
994  *
995  * Hardware may support different number or arrangement of doorbell bits.
996  *
997  * Return: A mask of doorbell bits supported by the ntb.
998  */
999 static inline u64 ntb_db_valid_mask(struct ntb_dev *ntb)
1000 {
1001 	return ntb->ops->db_valid_mask(ntb);
1002 }
1003 
1004 /**
1005  * ntb_db_vector_count() - get the number of doorbell interrupt vectors
1006  * @ntb:	NTB device context.
1007  *
1008  * Hardware may support different number of interrupt vectors.
1009  *
1010  * Return: The number of doorbell interrupt vectors.
1011  */
1012 static inline int ntb_db_vector_count(struct ntb_dev *ntb)
1013 {
1014 	if (!ntb->ops->db_vector_count)
1015 		return 1;
1016 
1017 	return ntb->ops->db_vector_count(ntb);
1018 }
1019 
1020 /**
1021  * ntb_db_vector_mask() - get a mask of doorbell bits serviced by a vector
1022  * @ntb:	NTB device context.
1023  * @vector:	Doorbell vector number.
1024  *
1025  * Each interrupt vector may have a different number or arrangement of bits.
1026  *
1027  * Return: A mask of doorbell bits serviced by a vector.
1028  */
1029 static inline u64 ntb_db_vector_mask(struct ntb_dev *ntb, int vector)
1030 {
1031 	if (!ntb->ops->db_vector_mask)
1032 		return ntb_db_valid_mask(ntb);
1033 
1034 	return ntb->ops->db_vector_mask(ntb, vector);
1035 }
1036 
1037 /**
1038  * ntb_db_read() - read the local doorbell register
1039  * @ntb:	NTB device context.
1040  *
1041  * Read the local doorbell register, and return the bits that are set.
1042  *
1043  * Return: The bits currently set in the local doorbell register.
1044  */
1045 static inline u64 ntb_db_read(struct ntb_dev *ntb)
1046 {
1047 	return ntb->ops->db_read(ntb);
1048 }
1049 
1050 /**
1051  * ntb_db_set() - set bits in the local doorbell register
1052  * @ntb:	NTB device context.
1053  * @db_bits:	Doorbell bits to set.
1054  *
1055  * Set bits in the local doorbell register, which may generate a local doorbell
1056  * interrupt.  Bits that were already set must remain set.
1057  *
1058  * This is unusual, and hardware may not support it.
1059  *
1060  * Return: Zero on success, otherwise an error number.
1061  */
1062 static inline int ntb_db_set(struct ntb_dev *ntb, u64 db_bits)
1063 {
1064 	if (!ntb->ops->db_set)
1065 		return -EINVAL;
1066 
1067 	return ntb->ops->db_set(ntb, db_bits);
1068 }
1069 
1070 /**
1071  * ntb_db_clear() - clear bits in the local doorbell register
1072  * @ntb:	NTB device context.
1073  * @db_bits:	Doorbell bits to clear.
1074  *
1075  * Clear bits in the local doorbell register, arming the bits for the next
1076  * doorbell.
1077  *
1078  * Return: Zero on success, otherwise an error number.
1079  */
1080 static inline int ntb_db_clear(struct ntb_dev *ntb, u64 db_bits)
1081 {
1082 	return ntb->ops->db_clear(ntb, db_bits);
1083 }
1084 
1085 /**
1086  * ntb_db_read_mask() - read the local doorbell mask
1087  * @ntb:	NTB device context.
1088  *
1089  * Read the local doorbell mask register, and return the bits that are set.
1090  *
1091  * This is unusual, though hardware is likely to support it.
1092  *
1093  * Return: The bits currently set in the local doorbell mask register.
1094  */
1095 static inline u64 ntb_db_read_mask(struct ntb_dev *ntb)
1096 {
1097 	if (!ntb->ops->db_read_mask)
1098 		return 0;
1099 
1100 	return ntb->ops->db_read_mask(ntb);
1101 }
1102 
1103 /**
1104  * ntb_db_set_mask() - set bits in the local doorbell mask
1105  * @ntb:	NTB device context.
1106  * @db_bits:	Doorbell mask bits to set.
1107  *
1108  * Set bits in the local doorbell mask register, preventing doorbell interrupts
1109  * from being generated for those doorbell bits.  Bits that were already set
1110  * must remain set.
1111  *
1112  * Return: Zero on success, otherwise an error number.
1113  */
1114 static inline int ntb_db_set_mask(struct ntb_dev *ntb, u64 db_bits)
1115 {
1116 	return ntb->ops->db_set_mask(ntb, db_bits);
1117 }
1118 
1119 /**
1120  * ntb_db_clear_mask() - clear bits in the local doorbell mask
1121  * @ntb:	NTB device context.
1122  * @db_bits:	Doorbell bits to clear.
1123  *
1124  * Clear bits in the local doorbell mask register, allowing doorbell interrupts
1125  * from being generated for those doorbell bits.  If a doorbell bit is already
1126  * set at the time the mask is cleared, and the corresponding mask bit is
1127  * changed from set to clear, then the ntb driver must ensure that
1128  * ntb_db_event() is called.  If the hardware does not generate the interrupt
1129  * on clearing the mask bit, then the driver must call ntb_db_event() anyway.
1130  *
1131  * Return: Zero on success, otherwise an error number.
1132  */
1133 static inline int ntb_db_clear_mask(struct ntb_dev *ntb, u64 db_bits)
1134 {
1135 	return ntb->ops->db_clear_mask(ntb, db_bits);
1136 }
1137 
1138 /**
1139  * ntb_peer_db_addr() - address and size of the peer doorbell register
1140  * @ntb:	NTB device context.
1141  * @db_addr:	OUT - The address of the peer doorbell register.
1142  * @db_size:	OUT - The number of bytes to write the peer doorbell register.
1143  * @db_data:	OUT - The data of peer doorbell register
1144  * @db_bit:		door bell bit number
1145  *
1146  * Return the address of the peer doorbell register.  This may be used, for
1147  * example, by drivers that offload memory copy operations to a dma engine.
1148  * The drivers may wish to ring the peer doorbell at the completion of memory
1149  * copy operations.  For efficiency, and to simplify ordering of operations
1150  * between the dma memory copies and the ringing doorbell, the driver may
1151  * append one additional dma memory copy with the doorbell register as the
1152  * destination, after the memory copy operations.
1153  *
1154  * Return: Zero on success, otherwise an error number.
1155  */
1156 static inline int ntb_peer_db_addr(struct ntb_dev *ntb,
1157 				   phys_addr_t *db_addr,
1158 				   resource_size_t *db_size,
1159 				   u64 *db_data, int db_bit)
1160 {
1161 	if (!ntb->ops->peer_db_addr)
1162 		return -EINVAL;
1163 
1164 	return ntb->ops->peer_db_addr(ntb, db_addr, db_size, db_data, db_bit);
1165 }
1166 
1167 /**
1168  * ntb_peer_db_read() - read the peer doorbell register
1169  * @ntb:	NTB device context.
1170  *
1171  * Read the peer doorbell register, and return the bits that are set.
1172  *
1173  * This is unusual, and hardware may not support it.
1174  *
1175  * Return: The bits currently set in the peer doorbell register.
1176  */
1177 static inline u64 ntb_peer_db_read(struct ntb_dev *ntb)
1178 {
1179 	if (!ntb->ops->peer_db_read)
1180 		return 0;
1181 
1182 	return ntb->ops->peer_db_read(ntb);
1183 }
1184 
1185 /**
1186  * ntb_peer_db_set() - set bits in the peer doorbell register
1187  * @ntb:	NTB device context.
1188  * @db_bits:	Doorbell bits to set.
1189  *
1190  * Set bits in the peer doorbell register, which may generate a peer doorbell
1191  * interrupt.  Bits that were already set must remain set.
1192  *
1193  * Return: Zero on success, otherwise an error number.
1194  */
1195 static inline int ntb_peer_db_set(struct ntb_dev *ntb, u64 db_bits)
1196 {
1197 	return ntb->ops->peer_db_set(ntb, db_bits);
1198 }
1199 
1200 /**
1201  * ntb_peer_db_clear() - clear bits in the peer doorbell register
1202  * @ntb:	NTB device context.
1203  * @db_bits:	Doorbell bits to clear.
1204  *
1205  * Clear bits in the peer doorbell register, arming the bits for the next
1206  * doorbell.
1207  *
1208  * This is unusual, and hardware may not support it.
1209  *
1210  * Return: Zero on success, otherwise an error number.
1211  */
1212 static inline int ntb_peer_db_clear(struct ntb_dev *ntb, u64 db_bits)
1213 {
1214 	if (!ntb->ops->db_clear)
1215 		return -EINVAL;
1216 
1217 	return ntb->ops->peer_db_clear(ntb, db_bits);
1218 }
1219 
1220 /**
1221  * ntb_peer_db_read_mask() - read the peer doorbell mask
1222  * @ntb:	NTB device context.
1223  *
1224  * Read the peer doorbell mask register, and return the bits that are set.
1225  *
1226  * This is unusual, and hardware may not support it.
1227  *
1228  * Return: The bits currently set in the peer doorbell mask register.
1229  */
1230 static inline u64 ntb_peer_db_read_mask(struct ntb_dev *ntb)
1231 {
1232 	if (!ntb->ops->db_read_mask)
1233 		return 0;
1234 
1235 	return ntb->ops->peer_db_read_mask(ntb);
1236 }
1237 
1238 /**
1239  * ntb_peer_db_set_mask() - set bits in the peer doorbell mask
1240  * @ntb:	NTB device context.
1241  * @db_bits:	Doorbell mask bits to set.
1242  *
1243  * Set bits in the peer doorbell mask register, preventing doorbell interrupts
1244  * from being generated for those doorbell bits.  Bits that were already set
1245  * must remain set.
1246  *
1247  * This is unusual, and hardware may not support it.
1248  *
1249  * Return: Zero on success, otherwise an error number.
1250  */
1251 static inline int ntb_peer_db_set_mask(struct ntb_dev *ntb, u64 db_bits)
1252 {
1253 	if (!ntb->ops->db_set_mask)
1254 		return -EINVAL;
1255 
1256 	return ntb->ops->peer_db_set_mask(ntb, db_bits);
1257 }
1258 
1259 /**
1260  * ntb_peer_db_clear_mask() - clear bits in the peer doorbell mask
1261  * @ntb:	NTB device context.
1262  * @db_bits:	Doorbell bits to clear.
1263  *
1264  * Clear bits in the peer doorbell mask register, allowing doorbell interrupts
1265  * from being generated for those doorbell bits.  If the hardware does not
1266  * generate the interrupt on clearing the mask bit, then the driver should not
1267  * implement this function!
1268  *
1269  * This is unusual, and hardware may not support it.
1270  *
1271  * Return: Zero on success, otherwise an error number.
1272  */
1273 static inline int ntb_peer_db_clear_mask(struct ntb_dev *ntb, u64 db_bits)
1274 {
1275 	if (!ntb->ops->db_clear_mask)
1276 		return -EINVAL;
1277 
1278 	return ntb->ops->peer_db_clear_mask(ntb, db_bits);
1279 }
1280 
1281 /**
1282  * ntb_spad_is_unsafe() - check if it is safe to use the hardware scratchpads
1283  * @ntb:	NTB device context.
1284  *
1285  * It is possible for some ntb hardware to be affected by errata.  Hardware
1286  * drivers can advise clients to avoid using scratchpads.  Clients may ignore
1287  * this advice, though caution is recommended.
1288  *
1289  * Return: Zero if it is safe to use scratchpads, or One if it is not safe.
1290  */
1291 static inline int ntb_spad_is_unsafe(struct ntb_dev *ntb)
1292 {
1293 	if (!ntb->ops->spad_is_unsafe)
1294 		return 0;
1295 
1296 	return ntb->ops->spad_is_unsafe(ntb);
1297 }
1298 
1299 /**
1300  * ntb_spad_count() - get the number of scratchpads
1301  * @ntb:	NTB device context.
1302  *
1303  * Hardware and topology may support a different number of scratchpads.
1304  * Although it must be the same for all ports per NTB device.
1305  *
1306  * Return: the number of scratchpads.
1307  */
1308 static inline int ntb_spad_count(struct ntb_dev *ntb)
1309 {
1310 	if (!ntb->ops->spad_count)
1311 		return 0;
1312 
1313 	return ntb->ops->spad_count(ntb);
1314 }
1315 
1316 /**
1317  * ntb_spad_read() - read the local scratchpad register
1318  * @ntb:	NTB device context.
1319  * @sidx:	Scratchpad index.
1320  *
1321  * Read the local scratchpad register, and return the value.
1322  *
1323  * Return: The value of the local scratchpad register.
1324  */
1325 static inline u32 ntb_spad_read(struct ntb_dev *ntb, int sidx)
1326 {
1327 	if (!ntb->ops->spad_read)
1328 		return ~(u32)0;
1329 
1330 	return ntb->ops->spad_read(ntb, sidx);
1331 }
1332 
1333 /**
1334  * ntb_spad_write() - write the local scratchpad register
1335  * @ntb:	NTB device context.
1336  * @sidx:	Scratchpad index.
1337  * @val:	Scratchpad value.
1338  *
1339  * Write the value to the local scratchpad register.
1340  *
1341  * Return: Zero on success, otherwise an error number.
1342  */
1343 static inline int ntb_spad_write(struct ntb_dev *ntb, int sidx, u32 val)
1344 {
1345 	if (!ntb->ops->spad_write)
1346 		return -EINVAL;
1347 
1348 	return ntb->ops->spad_write(ntb, sidx, val);
1349 }
1350 
1351 /**
1352  * ntb_peer_spad_addr() - address of the peer scratchpad register
1353  * @ntb:	NTB device context.
1354  * @pidx:	Port index of peer device.
1355  * @sidx:	Scratchpad index.
1356  * @spad_addr:	OUT - The address of the peer scratchpad register.
1357  *
1358  * Return the address of the peer scratchpad register.  This may be used, for
1359  * example, by drivers that offload memory copy operations to a dma engine.
1360  *
1361  * Return: Zero on success, otherwise an error number.
1362  */
1363 static inline int ntb_peer_spad_addr(struct ntb_dev *ntb, int pidx, int sidx,
1364 				     phys_addr_t *spad_addr)
1365 {
1366 	if (!ntb->ops->peer_spad_addr)
1367 		return -EINVAL;
1368 
1369 	return ntb->ops->peer_spad_addr(ntb, pidx, sidx, spad_addr);
1370 }
1371 
1372 /**
1373  * ntb_peer_spad_read() - read the peer scratchpad register
1374  * @ntb:	NTB device context.
1375  * @pidx:	Port index of peer device.
1376  * @sidx:	Scratchpad index.
1377  *
1378  * Read the peer scratchpad register, and return the value.
1379  *
1380  * Return: The value of the peer scratchpad register.
1381  */
1382 static inline u32 ntb_peer_spad_read(struct ntb_dev *ntb, int pidx, int sidx)
1383 {
1384 	if (!ntb->ops->peer_spad_read)
1385 		return ~(u32)0;
1386 
1387 	return ntb->ops->peer_spad_read(ntb, pidx, sidx);
1388 }
1389 
1390 /**
1391  * ntb_peer_spad_write() - write the peer scratchpad register
1392  * @ntb:	NTB device context.
1393  * @pidx:	Port index of peer device.
1394  * @sidx:	Scratchpad index.
1395  * @val:	Scratchpad value.
1396  *
1397  * Write the value to the peer scratchpad register.
1398  *
1399  * Return: Zero on success, otherwise an error number.
1400  */
1401 static inline int ntb_peer_spad_write(struct ntb_dev *ntb, int pidx, int sidx,
1402 				      u32 val)
1403 {
1404 	if (!ntb->ops->peer_spad_write)
1405 		return -EINVAL;
1406 
1407 	return ntb->ops->peer_spad_write(ntb, pidx, sidx, val);
1408 }
1409 
1410 /**
1411  * ntb_msg_count() - get the number of message registers
1412  * @ntb:	NTB device context.
1413  *
1414  * Hardware may support a different number of message registers.
1415  *
1416  * Return: the number of message registers.
1417  */
1418 static inline int ntb_msg_count(struct ntb_dev *ntb)
1419 {
1420 	if (!ntb->ops->msg_count)
1421 		return 0;
1422 
1423 	return ntb->ops->msg_count(ntb);
1424 }
1425 
1426 /**
1427  * ntb_msg_inbits() - get a bitfield of inbound message registers status
1428  * @ntb:	NTB device context.
1429  *
1430  * The method returns the bitfield of status and mask registers, which related
1431  * to inbound message registers.
1432  *
1433  * Return: bitfield of inbound message registers.
1434  */
1435 static inline u64 ntb_msg_inbits(struct ntb_dev *ntb)
1436 {
1437 	if (!ntb->ops->msg_inbits)
1438 		return 0;
1439 
1440 	return ntb->ops->msg_inbits(ntb);
1441 }
1442 
1443 /**
1444  * ntb_msg_outbits() - get a bitfield of outbound message registers status
1445  * @ntb:	NTB device context.
1446  *
1447  * The method returns the bitfield of status and mask registers, which related
1448  * to outbound message registers.
1449  *
1450  * Return: bitfield of outbound message registers.
1451  */
1452 static inline u64 ntb_msg_outbits(struct ntb_dev *ntb)
1453 {
1454 	if (!ntb->ops->msg_outbits)
1455 		return 0;
1456 
1457 	return ntb->ops->msg_outbits(ntb);
1458 }
1459 
1460 /**
1461  * ntb_msg_read_sts() - read the message registers status
1462  * @ntb:	NTB device context.
1463  *
1464  * Read the status of message register. Inbound and outbound message registers
1465  * related bits can be filtered by masks retrieved from ntb_msg_inbits() and
1466  * ntb_msg_outbits().
1467  *
1468  * Return: status bits of message registers
1469  */
1470 static inline u64 ntb_msg_read_sts(struct ntb_dev *ntb)
1471 {
1472 	if (!ntb->ops->msg_read_sts)
1473 		return 0;
1474 
1475 	return ntb->ops->msg_read_sts(ntb);
1476 }
1477 
1478 /**
1479  * ntb_msg_clear_sts() - clear status bits of message registers
1480  * @ntb:	NTB device context.
1481  * @sts_bits:	Status bits to clear.
1482  *
1483  * Clear bits in the status register.
1484  *
1485  * Return: Zero on success, otherwise a negative error number.
1486  */
1487 static inline int ntb_msg_clear_sts(struct ntb_dev *ntb, u64 sts_bits)
1488 {
1489 	if (!ntb->ops->msg_clear_sts)
1490 		return -EINVAL;
1491 
1492 	return ntb->ops->msg_clear_sts(ntb, sts_bits);
1493 }
1494 
1495 /**
1496  * ntb_msg_set_mask() - set mask of message register status bits
1497  * @ntb:	NTB device context.
1498  * @mask_bits:	Mask bits.
1499  *
1500  * Mask the message registers status bits from raising the message event.
1501  *
1502  * Return: Zero on success, otherwise a negative error number.
1503  */
1504 static inline int ntb_msg_set_mask(struct ntb_dev *ntb, u64 mask_bits)
1505 {
1506 	if (!ntb->ops->msg_set_mask)
1507 		return -EINVAL;
1508 
1509 	return ntb->ops->msg_set_mask(ntb, mask_bits);
1510 }
1511 
1512 /**
1513  * ntb_msg_clear_mask() - clear message registers mask
1514  * @ntb:	NTB device context.
1515  * @mask_bits:	Mask bits to clear.
1516  *
1517  * Clear bits in the message events mask register.
1518  *
1519  * Return: Zero on success, otherwise a negative error number.
1520  */
1521 static inline int ntb_msg_clear_mask(struct ntb_dev *ntb, u64 mask_bits)
1522 {
1523 	if (!ntb->ops->msg_clear_mask)
1524 		return -EINVAL;
1525 
1526 	return ntb->ops->msg_clear_mask(ntb, mask_bits);
1527 }
1528 
1529 /**
1530  * ntb_msg_read() - read inbound message register with specified index
1531  * @ntb:	NTB device context.
1532  * @pidx:	OUT - Port index of peer device a message retrieved from
1533  * @midx:	Message register index
1534  *
1535  * Read data from the specified message register. Source port index of a
1536  * message is retrieved as well.
1537  *
1538  * Return: The value of the inbound message register.
1539  */
1540 static inline u32 ntb_msg_read(struct ntb_dev *ntb, int *pidx, int midx)
1541 {
1542 	if (!ntb->ops->msg_read)
1543 		return ~(u32)0;
1544 
1545 	return ntb->ops->msg_read(ntb, pidx, midx);
1546 }
1547 
1548 /**
1549  * ntb_peer_msg_write() - write data to the specified peer message register
1550  * @ntb:	NTB device context.
1551  * @pidx:	Port index of peer device a message being sent to
1552  * @midx:	Message register index
1553  * @msg:	Data to send
1554  *
1555  * Send data to a specified peer device using the defined message register.
1556  * Message event can be raised if the midx registers isn't empty while
1557  * calling this method and the corresponding interrupt isn't masked.
1558  *
1559  * Return: Zero on success, otherwise a negative error number.
1560  */
1561 static inline int ntb_peer_msg_write(struct ntb_dev *ntb, int pidx, int midx,
1562 				     u32 msg)
1563 {
1564 	if (!ntb->ops->peer_msg_write)
1565 		return -EINVAL;
1566 
1567 	return ntb->ops->peer_msg_write(ntb, pidx, midx, msg);
1568 }
1569 
1570 /**
1571  * ntb_get_dma_dev() - get the device to use for DMA allocations/mappings
1572  * @ntb:	NTB device context.
1573  *
1574  * Return a struct device suitable for DMA API allocations and mappings.
1575  * This is typically the parent of the NTB device, but may be overridden by a
1576  * driver by implementing .get_dma_dev().
1577  *
1578  * Drivers that implement .get_dma_dev() must return a non-NULL pointer.
1579  *
1580  * Return: device pointer to use for DMA operations.
1581  */
1582 static inline struct device *ntb_get_dma_dev(struct ntb_dev *ntb)
1583 {
1584 	if (!ntb->ops->get_dma_dev)
1585 		return ntb->dev.parent;
1586 
1587 	return ntb->ops->get_dma_dev(ntb);
1588 }
1589 
1590 /**
1591  * ntb_peer_resource_idx() - get a resource index for a given peer idx
1592  * @ntb:	NTB device context.
1593  * @pidx:	Peer port index.
1594  *
1595  * When constructing a graph of peers, each remote peer must use a different
1596  * resource index (mw, doorbell, etc) to communicate with each other
1597  * peer.
1598  *
1599  * In a two peer system, this function should always return 0 such that
1600  * resource 0 points to the remote peer on both ports.
1601  *
1602  * In a 5 peer system, this function will return the following matrix
1603  *
1604  * pidx \ port    0    1    2    3    4
1605  * 0              0    0    1    2    3
1606  * 1              0    1    1    2    3
1607  * 2              0    1    2    2    3
1608  * 3              0    1    2    3    3
1609  *
1610  * For example, if this function is used to program peer's memory
1611  * windows, port 0 will program MW 0 on all it's peers to point to itself.
1612  * port 1 will program MW 0 in port 0 to point to itself and MW 1 on all
1613  * other ports. etc.
1614  *
1615  * For the legacy two host case, ntb_port_number() and ntb_peer_port_number()
1616  * both return zero and therefore this function will always return zero.
1617  * So MW 0 on each host would be programmed to point to the other host.
1618  *
1619  * Return: the resource index to use for that peer.
1620  */
1621 static inline int ntb_peer_resource_idx(struct ntb_dev *ntb, int pidx)
1622 {
1623 	int local_port, peer_port;
1624 
1625 	if (pidx >= ntb_peer_port_count(ntb))
1626 		return -EINVAL;
1627 
1628 	local_port = ntb_logical_port_number(ntb);
1629 	peer_port = ntb_peer_logical_port_number(ntb, pidx);
1630 
1631 	if (peer_port < local_port)
1632 		return local_port - 1;
1633 	else
1634 		return local_port;
1635 }
1636 
1637 /**
1638  * ntb_peer_highest_mw_idx() - get a memory window index for a given peer idx
1639  *	using the highest index memory windows first
1640  *
1641  * @ntb:	NTB device context.
1642  * @pidx:	Peer port index.
1643  *
1644  * Like ntb_peer_resource_idx(), except it returns indexes starting with
1645  * last memory window index.
1646  *
1647  * Return: the resource index to use for that peer.
1648  */
1649 static inline int ntb_peer_highest_mw_idx(struct ntb_dev *ntb, int pidx)
1650 {
1651 	int ret;
1652 
1653 	ret = ntb_peer_resource_idx(ntb, pidx);
1654 	if (ret < 0)
1655 		return ret;
1656 
1657 	return ntb_mw_count(ntb, pidx) - ret - 1;
1658 }
1659 
1660 struct ntb_msi_desc {
1661 	u32 addr_offset;
1662 	u32 data;
1663 };
1664 
1665 #ifdef CONFIG_NTB_MSI
1666 
1667 int ntb_msi_init(struct ntb_dev *ntb, void (*desc_changed)(void *ctx));
1668 int ntb_msi_setup_mws(struct ntb_dev *ntb);
1669 void ntb_msi_clear_mws(struct ntb_dev *ntb);
1670 int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb, irq_handler_t handler,
1671 				  irq_handler_t thread_fn,
1672 				  const char *name, void *dev_id,
1673 				  struct ntb_msi_desc *msi_desc);
1674 int ntb_msi_peer_trigger(struct ntb_dev *ntb, int peer,
1675 			 struct ntb_msi_desc *desc);
1676 
1677 #else /* not CONFIG_NTB_MSI */
1678 
1679 static inline int ntb_msi_init(struct ntb_dev *ntb,
1680 			       void (*desc_changed)(void *ctx))
1681 {
1682 	return -EOPNOTSUPP;
1683 }
1684 static inline int ntb_msi_setup_mws(struct ntb_dev *ntb)
1685 {
1686 	return -EOPNOTSUPP;
1687 }
1688 static inline void ntb_msi_clear_mws(struct ntb_dev *ntb) {}
1689 static inline int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb,
1690 						irq_handler_t handler,
1691 						irq_handler_t thread_fn,
1692 						const char *name, void *dev_id,
1693 						struct ntb_msi_desc *msi_desc)
1694 {
1695 	return -EOPNOTSUPP;
1696 }
1697 static inline int ntb_msi_peer_trigger(struct ntb_dev *ntb, int peer,
1698 				       struct ntb_msi_desc *desc)
1699 {
1700 	return -EOPNOTSUPP;
1701 }
1702 #endif /* CONFIG_NTB_MSI */
1703 
1704 static inline int ntbm_msi_request_irq(struct ntb_dev *ntb,
1705 				       irq_handler_t handler,
1706 				       const char *name, void *dev_id,
1707 				       struct ntb_msi_desc *msi_desc)
1708 {
1709 	return ntbm_msi_request_threaded_irq(ntb, handler, NULL, name,
1710 					     dev_id, msi_desc);
1711 }
1712 
1713 #endif
1714