xref: /openbmc/linux/include/scsi/scsi_host.h (revision 04301bf5)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _SCSI_SCSI_HOST_H
3 #define _SCSI_SCSI_HOST_H
4 
5 #include <linux/device.h>
6 #include <linux/list.h>
7 #include <linux/types.h>
8 #include <linux/workqueue.h>
9 #include <linux/mutex.h>
10 #include <linux/seq_file.h>
11 #include <linux/blk-mq.h>
12 #include <scsi/scsi.h>
13 
14 struct block_device;
15 struct completion;
16 struct module;
17 struct scsi_cmnd;
18 struct scsi_device;
19 struct scsi_host_cmd_pool;
20 struct scsi_target;
21 struct Scsi_Host;
22 struct scsi_host_cmd_pool;
23 struct scsi_transport_template;
24 
25 
26 #define SG_ALL	SG_CHUNK_SIZE
27 
28 #define MODE_UNKNOWN 0x00
29 #define MODE_INITIATOR 0x01
30 #define MODE_TARGET 0x02
31 
32 struct scsi_host_template {
33 	struct module *module;
34 	const char *name;
35 
36 	/*
37 	 * The info function will return whatever useful information the
38 	 * developer sees fit.  If not provided, then the name field will
39 	 * be used instead.
40 	 *
41 	 * Status: OPTIONAL
42 	 */
43 	const char *(* info)(struct Scsi_Host *);
44 
45 	/*
46 	 * Ioctl interface
47 	 *
48 	 * Status: OPTIONAL
49 	 */
50 	int (*ioctl)(struct scsi_device *dev, unsigned int cmd,
51 		     void __user *arg);
52 
53 
54 #ifdef CONFIG_COMPAT
55 	/*
56 	 * Compat handler. Handle 32bit ABI.
57 	 * When unknown ioctl is passed return -ENOIOCTLCMD.
58 	 *
59 	 * Status: OPTIONAL
60 	 */
61 	int (*compat_ioctl)(struct scsi_device *dev, unsigned int cmd,
62 			    void __user *arg);
63 #endif
64 
65 	int (*init_cmd_priv)(struct Scsi_Host *shost, struct scsi_cmnd *cmd);
66 	int (*exit_cmd_priv)(struct Scsi_Host *shost, struct scsi_cmnd *cmd);
67 
68 	/*
69 	 * The queuecommand function is used to queue up a scsi
70 	 * command block to the LLDD.  When the driver finished
71 	 * processing the command the done callback is invoked.
72 	 *
73 	 * If queuecommand returns 0, then the driver has accepted the
74 	 * command.  It must also push it to the HBA if the scsi_cmnd
75 	 * flag SCMD_LAST is set, or if the driver does not implement
76 	 * commit_rqs.  The done() function must be called on the command
77 	 * when the driver has finished with it. (you may call done on the
78 	 * command before queuecommand returns, but in this case you
79 	 * *must* return 0 from queuecommand).
80 	 *
81 	 * Queuecommand may also reject the command, in which case it may
82 	 * not touch the command and must not call done() for it.
83 	 *
84 	 * There are two possible rejection returns:
85 	 *
86 	 *   SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but
87 	 *   allow commands to other devices serviced by this host.
88 	 *
89 	 *   SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this
90 	 *   host temporarily.
91 	 *
92          * For compatibility, any other non-zero return is treated the
93          * same as SCSI_MLQUEUE_HOST_BUSY.
94 	 *
95 	 * NOTE: "temporarily" means either until the next command for#
96 	 * this device/host completes, or a period of time determined by
97 	 * I/O pressure in the system if there are no other outstanding
98 	 * commands.
99 	 *
100 	 * STATUS: REQUIRED
101 	 */
102 	int (* queuecommand)(struct Scsi_Host *, struct scsi_cmnd *);
103 
104 	/*
105 	 * The commit_rqs function is used to trigger a hardware
106 	 * doorbell after some requests have been queued with
107 	 * queuecommand, when an error is encountered before sending
108 	 * the request with SCMD_LAST set.
109 	 *
110 	 * STATUS: OPTIONAL
111 	 */
112 	void (*commit_rqs)(struct Scsi_Host *, u16);
113 
114 	/*
115 	 * This is an error handling strategy routine.  You don't need to
116 	 * define one of these if you don't want to - there is a default
117 	 * routine that is present that should work in most cases.  For those
118 	 * driver authors that have the inclination and ability to write their
119 	 * own strategy routine, this is where it is specified.  Note - the
120 	 * strategy routine is *ALWAYS* run in the context of the kernel eh
121 	 * thread.  Thus you are guaranteed to *NOT* be in an interrupt
122 	 * handler when you execute this, and you are also guaranteed to
123 	 * *NOT* have any other commands being queued while you are in the
124 	 * strategy routine. When you return from this function, operations
125 	 * return to normal.
126 	 *
127 	 * See scsi_error.c scsi_unjam_host for additional comments about
128 	 * what this function should and should not be attempting to do.
129 	 *
130 	 * Status: REQUIRED	(at least one of them)
131 	 */
132 	int (* eh_abort_handler)(struct scsi_cmnd *);
133 	int (* eh_device_reset_handler)(struct scsi_cmnd *);
134 	int (* eh_target_reset_handler)(struct scsi_cmnd *);
135 	int (* eh_bus_reset_handler)(struct scsi_cmnd *);
136 	int (* eh_host_reset_handler)(struct scsi_cmnd *);
137 
138 	/*
139 	 * Before the mid layer attempts to scan for a new device where none
140 	 * currently exists, it will call this entry in your driver.  Should
141 	 * your driver need to allocate any structs or perform any other init
142 	 * items in order to send commands to a currently unused target/lun
143 	 * combo, then this is where you can perform those allocations.  This
144 	 * is specifically so that drivers won't have to perform any kind of
145 	 * "is this a new device" checks in their queuecommand routine,
146 	 * thereby making the hot path a bit quicker.
147 	 *
148 	 * Return values: 0 on success, non-0 on failure
149 	 *
150 	 * Deallocation:  If we didn't find any devices at this ID, you will
151 	 * get an immediate call to slave_destroy().  If we find something
152 	 * here then you will get a call to slave_configure(), then the
153 	 * device will be used for however long it is kept around, then when
154 	 * the device is removed from the system (or * possibly at reboot
155 	 * time), you will then get a call to slave_destroy().  This is
156 	 * assuming you implement slave_configure and slave_destroy.
157 	 * However, if you allocate memory and hang it off the device struct,
158 	 * then you must implement the slave_destroy() routine at a minimum
159 	 * in order to avoid leaking memory
160 	 * each time a device is tore down.
161 	 *
162 	 * Status: OPTIONAL
163 	 */
164 	int (* slave_alloc)(struct scsi_device *);
165 
166 	/*
167 	 * Once the device has responded to an INQUIRY and we know the
168 	 * device is online, we call into the low level driver with the
169 	 * struct scsi_device *.  If the low level device driver implements
170 	 * this function, it *must* perform the task of setting the queue
171 	 * depth on the device.  All other tasks are optional and depend
172 	 * on what the driver supports and various implementation details.
173 	 *
174 	 * Things currently recommended to be handled at this time include:
175 	 *
176 	 * 1.  Setting the device queue depth.  Proper setting of this is
177 	 *     described in the comments for scsi_change_queue_depth.
178 	 * 2.  Determining if the device supports the various synchronous
179 	 *     negotiation protocols.  The device struct will already have
180 	 *     responded to INQUIRY and the results of the standard items
181 	 *     will have been shoved into the various device flag bits, eg.
182 	 *     device->sdtr will be true if the device supports SDTR messages.
183 	 * 3.  Allocating command structs that the device will need.
184 	 * 4.  Setting the default timeout on this device (if needed).
185 	 * 5.  Anything else the low level driver might want to do on a device
186 	 *     specific setup basis...
187 	 * 6.  Return 0 on success, non-0 on error.  The device will be marked
188 	 *     as offline on error so that no access will occur.  If you return
189 	 *     non-0, your slave_destroy routine will never get called for this
190 	 *     device, so don't leave any loose memory hanging around, clean
191 	 *     up after yourself before returning non-0
192 	 *
193 	 * Status: OPTIONAL
194 	 */
195 	int (* slave_configure)(struct scsi_device *);
196 
197 	/*
198 	 * Immediately prior to deallocating the device and after all activity
199 	 * has ceased the mid layer calls this point so that the low level
200 	 * driver may completely detach itself from the scsi device and vice
201 	 * versa.  The low level driver is responsible for freeing any memory
202 	 * it allocated in the slave_alloc or slave_configure calls.
203 	 *
204 	 * Status: OPTIONAL
205 	 */
206 	void (* slave_destroy)(struct scsi_device *);
207 
208 	/*
209 	 * Before the mid layer attempts to scan for a new device attached
210 	 * to a target where no target currently exists, it will call this
211 	 * entry in your driver.  Should your driver need to allocate any
212 	 * structs or perform any other init items in order to send commands
213 	 * to a currently unused target, then this is where you can perform
214 	 * those allocations.
215 	 *
216 	 * Return values: 0 on success, non-0 on failure
217 	 *
218 	 * Status: OPTIONAL
219 	 */
220 	int (* target_alloc)(struct scsi_target *);
221 
222 	/*
223 	 * Immediately prior to deallocating the target structure, and
224 	 * after all activity to attached scsi devices has ceased, the
225 	 * midlayer calls this point so that the driver may deallocate
226 	 * and terminate any references to the target.
227 	 *
228 	 * Status: OPTIONAL
229 	 */
230 	void (* target_destroy)(struct scsi_target *);
231 
232 	/*
233 	 * If a host has the ability to discover targets on its own instead
234 	 * of scanning the entire bus, it can fill in this function and
235 	 * call scsi_scan_host().  This function will be called periodically
236 	 * until it returns 1 with the scsi_host and the elapsed time of
237 	 * the scan in jiffies.
238 	 *
239 	 * Status: OPTIONAL
240 	 */
241 	int (* scan_finished)(struct Scsi_Host *, unsigned long);
242 
243 	/*
244 	 * If the host wants to be called before the scan starts, but
245 	 * after the midlayer has set up ready for the scan, it can fill
246 	 * in this function.
247 	 *
248 	 * Status: OPTIONAL
249 	 */
250 	void (* scan_start)(struct Scsi_Host *);
251 
252 	/*
253 	 * Fill in this function to allow the queue depth of this host
254 	 * to be changeable (on a per device basis).  Returns either
255 	 * the current queue depth setting (may be different from what
256 	 * was passed in) or an error.  An error should only be
257 	 * returned if the requested depth is legal but the driver was
258 	 * unable to set it.  If the requested depth is illegal, the
259 	 * driver should set and return the closest legal queue depth.
260 	 *
261 	 * Status: OPTIONAL
262 	 */
263 	int (* change_queue_depth)(struct scsi_device *, int);
264 
265 	/*
266 	 * This functions lets the driver expose the queue mapping
267 	 * to the block layer.
268 	 *
269 	 * Status: OPTIONAL
270 	 */
271 	int (* map_queues)(struct Scsi_Host *shost);
272 
273 	/*
274 	 * Check if scatterlists need to be padded for DMA draining.
275 	 *
276 	 * Status: OPTIONAL
277 	 */
278 	bool (* dma_need_drain)(struct request *rq);
279 
280 	/*
281 	 * This function determines the BIOS parameters for a given
282 	 * harddisk.  These tend to be numbers that are made up by
283 	 * the host adapter.  Parameters:
284 	 * size, device, list (heads, sectors, cylinders)
285 	 *
286 	 * Status: OPTIONAL
287 	 */
288 	int (* bios_param)(struct scsi_device *, struct block_device *,
289 			sector_t, int []);
290 
291 	/*
292 	 * This function is called when one or more partitions on the
293 	 * device reach beyond the end of the device.
294 	 *
295 	 * Status: OPTIONAL
296 	 */
297 	void (*unlock_native_capacity)(struct scsi_device *);
298 
299 	/*
300 	 * Can be used to export driver statistics and other infos to the
301 	 * world outside the kernel ie. userspace and it also provides an
302 	 * interface to feed the driver with information.
303 	 *
304 	 * Status: OBSOLETE
305 	 */
306 	int (*show_info)(struct seq_file *, struct Scsi_Host *);
307 	int (*write_info)(struct Scsi_Host *, char *, int);
308 
309 	/*
310 	 * This is an optional routine that allows the transport to become
311 	 * involved when a scsi io timer fires. The return value tells the
312 	 * timer routine how to finish the io timeout handling.
313 	 *
314 	 * Status: OPTIONAL
315 	 */
316 	enum blk_eh_timer_return (*eh_timed_out)(struct scsi_cmnd *);
317 
318 	/* This is an optional routine that allows transport to initiate
319 	 * LLD adapter or firmware reset using sysfs attribute.
320 	 *
321 	 * Return values: 0 on success, -ve value on failure.
322 	 *
323 	 * Status: OPTIONAL
324 	 */
325 
326 	int (*host_reset)(struct Scsi_Host *shost, int reset_type);
327 #define SCSI_ADAPTER_RESET	1
328 #define SCSI_FIRMWARE_RESET	2
329 
330 
331 	/*
332 	 * Name of proc directory
333 	 */
334 	const char *proc_name;
335 
336 	/*
337 	 * Used to store the procfs directory if a driver implements the
338 	 * show_info method.
339 	 */
340 	struct proc_dir_entry *proc_dir;
341 
342 	/*
343 	 * This determines if we will use a non-interrupt driven
344 	 * or an interrupt driven scheme.  It is set to the maximum number
345 	 * of simultaneous commands a single hw queue in HBA will accept.
346 	 */
347 	int can_queue;
348 
349 	/*
350 	 * In many instances, especially where disconnect / reconnect are
351 	 * supported, our host also has an ID on the SCSI bus.  If this is
352 	 * the case, then it must be reserved.  Please set this_id to -1 if
353 	 * your setup is in single initiator mode, and the host lacks an
354 	 * ID.
355 	 */
356 	int this_id;
357 
358 	/*
359 	 * This determines the degree to which the host adapter is capable
360 	 * of scatter-gather.
361 	 */
362 	unsigned short sg_tablesize;
363 	unsigned short sg_prot_tablesize;
364 
365 	/*
366 	 * Set this if the host adapter has limitations beside segment count.
367 	 */
368 	unsigned int max_sectors;
369 
370 	/*
371 	 * Maximum size in bytes of a single segment.
372 	 */
373 	unsigned int max_segment_size;
374 
375 	/*
376 	 * DMA scatter gather segment boundary limit. A segment crossing this
377 	 * boundary will be split in two.
378 	 */
379 	unsigned long dma_boundary;
380 
381 	unsigned long virt_boundary_mask;
382 
383 	/*
384 	 * This specifies "machine infinity" for host templates which don't
385 	 * limit the transfer size.  Note this limit represents an absolute
386 	 * maximum, and may be over the transfer limits allowed for
387 	 * individual devices (e.g. 256 for SCSI-1).
388 	 */
389 #define SCSI_DEFAULT_MAX_SECTORS	1024
390 
391 	/*
392 	 * True if this host adapter can make good use of linked commands.
393 	 * This will allow more than one command to be queued to a given
394 	 * unit on a given host.  Set this to the maximum number of command
395 	 * blocks to be provided for each device.  Set this to 1 for one
396 	 * command block per lun, 2 for two, etc.  Do not set this to 0.
397 	 * You should make sure that the host adapter will do the right thing
398 	 * before you try setting this above 1.
399 	 */
400 	short cmd_per_lun;
401 
402 	/*
403 	 * present contains counter indicating how many boards of this
404 	 * type were found when we did the scan.
405 	 */
406 	unsigned char present;
407 
408 	/* If use block layer to manage tags, this is tag allocation policy */
409 	int tag_alloc_policy;
410 
411 	/*
412 	 * Track QUEUE_FULL events and reduce queue depth on demand.
413 	 */
414 	unsigned track_queue_depth:1;
415 
416 	/*
417 	 * This specifies the mode that a LLD supports.
418 	 */
419 	unsigned supported_mode:2;
420 
421 	/*
422 	 * True if this host adapter uses unchecked DMA onto an ISA bus.
423 	 */
424 	unsigned unchecked_isa_dma:1;
425 
426 	/*
427 	 * True for emulated SCSI host adapters (e.g. ATAPI).
428 	 */
429 	unsigned emulated:1;
430 
431 	/*
432 	 * True if the low-level driver performs its own reset-settle delays.
433 	 */
434 	unsigned skip_settle_delay:1;
435 
436 	/* True if the controller does not support WRITE SAME */
437 	unsigned no_write_same:1;
438 
439 	/*
440 	 * Countdown for host blocking with no commands outstanding.
441 	 */
442 	unsigned int max_host_blocked;
443 
444 	/*
445 	 * Default value for the blocking.  If the queue is empty,
446 	 * host_blocked counts down in the request_fn until it restarts
447 	 * host operations as zero is reached.
448 	 *
449 	 * FIXME: This should probably be a value in the template
450 	 */
451 #define SCSI_DEFAULT_HOST_BLOCKED	7
452 
453 	/*
454 	 * Pointer to the sysfs class properties for this host, NULL terminated.
455 	 */
456 	struct device_attribute **shost_attrs;
457 
458 	/*
459 	 * Pointer to the SCSI device properties for this host, NULL terminated.
460 	 */
461 	struct device_attribute **sdev_attrs;
462 
463 	/*
464 	 * Pointer to the SCSI device attribute groups for this host,
465 	 * NULL terminated.
466 	 */
467 	const struct attribute_group **sdev_groups;
468 
469 	/*
470 	 * Vendor Identifier associated with the host
471 	 *
472 	 * Note: When specifying vendor_id, be sure to read the
473 	 *   Vendor Type and ID formatting requirements specified in
474 	 *   scsi_netlink.h
475 	 */
476 	u64 vendor_id;
477 
478 	/*
479 	 * Additional per-command data allocated for the driver.
480 	 */
481 	unsigned int cmd_size;
482 	struct scsi_host_cmd_pool *cmd_pool;
483 
484 	/* Delay for runtime autosuspend */
485 	int rpm_autosuspend_delay;
486 };
487 
488 /*
489  * Temporary #define for host lock push down. Can be removed when all
490  * drivers have been updated to take advantage of unlocked
491  * queuecommand.
492  *
493  */
494 #define DEF_SCSI_QCMD(func_name) \
495 	int func_name(struct Scsi_Host *shost, struct scsi_cmnd *cmd)	\
496 	{								\
497 		unsigned long irq_flags;				\
498 		int rc;							\
499 		spin_lock_irqsave(shost->host_lock, irq_flags);		\
500 		rc = func_name##_lck (cmd, cmd->scsi_done);			\
501 		spin_unlock_irqrestore(shost->host_lock, irq_flags);	\
502 		return rc;						\
503 	}
504 
505 
506 /*
507  * shost state: If you alter this, you also need to alter scsi_sysfs.c
508  * (for the ascii descriptions) and the state model enforcer:
509  * scsi_host_set_state()
510  */
511 enum scsi_host_state {
512 	SHOST_CREATED = 1,
513 	SHOST_RUNNING,
514 	SHOST_CANCEL,
515 	SHOST_DEL,
516 	SHOST_RECOVERY,
517 	SHOST_CANCEL_RECOVERY,
518 	SHOST_DEL_RECOVERY,
519 };
520 
521 struct Scsi_Host {
522 	/*
523 	 * __devices is protected by the host_lock, but you should
524 	 * usually use scsi_device_lookup / shost_for_each_device
525 	 * to access it and don't care about locking yourself.
526 	 * In the rare case of being in irq context you can use
527 	 * their __ prefixed variants with the lock held. NEVER
528 	 * access this list directly from a driver.
529 	 */
530 	struct list_head	__devices;
531 	struct list_head	__targets;
532 
533 	struct list_head	starved_list;
534 
535 	spinlock_t		default_lock;
536 	spinlock_t		*host_lock;
537 
538 	struct mutex		scan_mutex;/* serialize scanning activity */
539 
540 	struct list_head	eh_cmd_q;
541 	struct task_struct    * ehandler;  /* Error recovery thread. */
542 	struct completion     * eh_action; /* Wait for specific actions on the
543 					      host. */
544 	wait_queue_head_t       host_wait;
545 	struct scsi_host_template *hostt;
546 	struct scsi_transport_template *transportt;
547 
548 	/* Area to keep a shared tag map */
549 	struct blk_mq_tag_set	tag_set;
550 
551 	atomic_t host_blocked;
552 
553 	unsigned int host_failed;	   /* commands that failed.
554 					      protected by host_lock */
555 	unsigned int host_eh_scheduled;    /* EH scheduled without command */
556 
557 	unsigned int host_no;  /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
558 
559 	/* next two fields are used to bound the time spent in error handling */
560 	int eh_deadline;
561 	unsigned long last_reset;
562 
563 
564 	/*
565 	 * These three parameters can be used to allow for wide scsi,
566 	 * and for host adapters that support multiple busses
567 	 * The last two should be set to 1 more than the actual max id
568 	 * or lun (e.g. 8 for SCSI parallel systems).
569 	 */
570 	unsigned int max_channel;
571 	unsigned int max_id;
572 	u64 max_lun;
573 
574 	/*
575 	 * This is a unique identifier that must be assigned so that we
576 	 * have some way of identifying each detected host adapter properly
577 	 * and uniquely.  For hosts that do not support more than one card
578 	 * in the system at one time, this does not need to be set.  It is
579 	 * initialized to 0 in scsi_register.
580 	 */
581 	unsigned int unique_id;
582 
583 	/*
584 	 * The maximum length of SCSI commands that this host can accept.
585 	 * Probably 12 for most host adapters, but could be 16 for others.
586 	 * or 260 if the driver supports variable length cdbs.
587 	 * For drivers that don't set this field, a value of 12 is
588 	 * assumed.
589 	 */
590 	unsigned short max_cmd_len;
591 
592 	int this_id;
593 	int can_queue;
594 	short cmd_per_lun;
595 	short unsigned int sg_tablesize;
596 	short unsigned int sg_prot_tablesize;
597 	unsigned int max_sectors;
598 	unsigned int max_segment_size;
599 	unsigned long dma_boundary;
600 	unsigned long virt_boundary_mask;
601 	/*
602 	 * In scsi-mq mode, the number of hardware queues supported by the LLD.
603 	 *
604 	 * Note: it is assumed that each hardware queue has a queue depth of
605 	 * can_queue. In other words, the total queue depth per host
606 	 * is nr_hw_queues * can_queue.
607 	 */
608 	unsigned nr_hw_queues;
609 	unsigned active_mode:2;
610 	unsigned unchecked_isa_dma:1;
611 
612 	/*
613 	 * Host has requested that no further requests come through for the
614 	 * time being.
615 	 */
616 	unsigned host_self_blocked:1;
617 
618 	/*
619 	 * Host uses correct SCSI ordering not PC ordering. The bit is
620 	 * set for the minority of drivers whose authors actually read
621 	 * the spec ;).
622 	 */
623 	unsigned reverse_ordering:1;
624 
625 	/* Task mgmt function in progress */
626 	unsigned tmf_in_progress:1;
627 
628 	/* Asynchronous scan in progress */
629 	unsigned async_scan:1;
630 
631 	/* Don't resume host in EH */
632 	unsigned eh_noresume:1;
633 
634 	/* The controller does not support WRITE SAME */
635 	unsigned no_write_same:1;
636 
637 	/* Host responded with short (<36 bytes) INQUIRY result */
638 	unsigned short_inquiry:1;
639 
640 	/* The transport requires the LUN bits NOT to be stored in CDB[1] */
641 	unsigned no_scsi2_lun_in_cdb:1;
642 
643 	/*
644 	 * Optional work queue to be utilized by the transport
645 	 */
646 	char work_q_name[20];
647 	struct workqueue_struct *work_q;
648 
649 	/*
650 	 * Task management function work queue
651 	 */
652 	struct workqueue_struct *tmf_work_q;
653 
654 	/*
655 	 * Value host_blocked counts down from
656 	 */
657 	unsigned int max_host_blocked;
658 
659 	/* Protection Information */
660 	unsigned int prot_capabilities;
661 	unsigned char prot_guard_type;
662 
663 	/* legacy crap */
664 	unsigned long base;
665 	unsigned long io_port;
666 	unsigned char n_io_port;
667 	unsigned char dma_channel;
668 	unsigned int  irq;
669 
670 
671 	enum scsi_host_state shost_state;
672 
673 	/* ldm bits */
674 	struct device		shost_gendev, shost_dev;
675 
676 	/*
677 	 * Points to the transport data (if any) which is allocated
678 	 * separately
679 	 */
680 	void *shost_data;
681 
682 	/*
683 	 * Points to the physical bus device we'd use to do DMA
684 	 * Needed just in case we have virtual hosts.
685 	 */
686 	struct device *dma_dev;
687 
688 	/*
689 	 * We should ensure that this is aligned, both for better performance
690 	 * and also because some compilers (m68k) don't automatically force
691 	 * alignment to a long boundary.
692 	 */
693 	unsigned long hostdata[]  /* Used for storage of host specific stuff */
694 		__attribute__ ((aligned (sizeof(unsigned long))));
695 };
696 
697 #define		class_to_shost(d)	\
698 	container_of(d, struct Scsi_Host, shost_dev)
699 
700 #define shost_printk(prefix, shost, fmt, a...)	\
701 	dev_printk(prefix, &(shost)->shost_gendev, fmt, ##a)
702 
703 static inline void *shost_priv(struct Scsi_Host *shost)
704 {
705 	return (void *)shost->hostdata;
706 }
707 
708 int scsi_is_host_device(const struct device *);
709 
710 static inline struct Scsi_Host *dev_to_shost(struct device *dev)
711 {
712 	while (!scsi_is_host_device(dev)) {
713 		if (!dev->parent)
714 			return NULL;
715 		dev = dev->parent;
716 	}
717 	return container_of(dev, struct Scsi_Host, shost_gendev);
718 }
719 
720 static inline int scsi_host_in_recovery(struct Scsi_Host *shost)
721 {
722 	return shost->shost_state == SHOST_RECOVERY ||
723 		shost->shost_state == SHOST_CANCEL_RECOVERY ||
724 		shost->shost_state == SHOST_DEL_RECOVERY ||
725 		shost->tmf_in_progress;
726 }
727 
728 extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *);
729 extern void scsi_flush_work(struct Scsi_Host *);
730 
731 extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int);
732 extern int __must_check scsi_add_host_with_dma(struct Scsi_Host *,
733 					       struct device *,
734 					       struct device *);
735 extern void scsi_scan_host(struct Scsi_Host *);
736 extern void scsi_rescan_device(struct device *);
737 extern void scsi_remove_host(struct Scsi_Host *);
738 extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);
739 extern int scsi_host_busy(struct Scsi_Host *shost);
740 extern void scsi_host_put(struct Scsi_Host *t);
741 extern struct Scsi_Host *scsi_host_lookup(unsigned short);
742 extern const char *scsi_host_state_name(enum scsi_host_state);
743 extern void scsi_host_complete_all_commands(struct Scsi_Host *shost,
744 					    int status);
745 
746 static inline int __must_check scsi_add_host(struct Scsi_Host *host,
747 					     struct device *dev)
748 {
749 	return scsi_add_host_with_dma(host, dev, dev);
750 }
751 
752 static inline struct device *scsi_get_device(struct Scsi_Host *shost)
753 {
754         return shost->shost_gendev.parent;
755 }
756 
757 /**
758  * scsi_host_scan_allowed - Is scanning of this host allowed
759  * @shost:	Pointer to Scsi_Host.
760  **/
761 static inline int scsi_host_scan_allowed(struct Scsi_Host *shost)
762 {
763 	return shost->shost_state == SHOST_RUNNING ||
764 	       shost->shost_state == SHOST_RECOVERY;
765 }
766 
767 extern void scsi_unblock_requests(struct Scsi_Host *);
768 extern void scsi_block_requests(struct Scsi_Host *);
769 extern int scsi_host_block(struct Scsi_Host *shost);
770 extern int scsi_host_unblock(struct Scsi_Host *shost, int new_state);
771 
772 void scsi_host_busy_iter(struct Scsi_Host *,
773 			 bool (*fn)(struct scsi_cmnd *, void *, bool), void *priv);
774 
775 struct class_container;
776 
777 /*
778  * These two functions are used to allocate and free a pseudo device
779  * which will connect to the host adapter itself rather than any
780  * physical device.  You must deallocate when you are done with the
781  * thing.  This physical pseudo-device isn't real and won't be available
782  * from any high-level drivers.
783  */
784 extern void scsi_free_host_dev(struct scsi_device *);
785 extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *);
786 
787 /*
788  * DIF defines the exchange of protection information between
789  * initiator and SBC block device.
790  *
791  * DIX defines the exchange of protection information between OS and
792  * initiator.
793  */
794 enum scsi_host_prot_capabilities {
795 	SHOST_DIF_TYPE1_PROTECTION = 1 << 0, /* T10 DIF Type 1 */
796 	SHOST_DIF_TYPE2_PROTECTION = 1 << 1, /* T10 DIF Type 2 */
797 	SHOST_DIF_TYPE3_PROTECTION = 1 << 2, /* T10 DIF Type 3 */
798 
799 	SHOST_DIX_TYPE0_PROTECTION = 1 << 3, /* DIX between OS and HBA only */
800 	SHOST_DIX_TYPE1_PROTECTION = 1 << 4, /* DIX with DIF Type 1 */
801 	SHOST_DIX_TYPE2_PROTECTION = 1 << 5, /* DIX with DIF Type 2 */
802 	SHOST_DIX_TYPE3_PROTECTION = 1 << 6, /* DIX with DIF Type 3 */
803 };
804 
805 /*
806  * SCSI hosts which support the Data Integrity Extensions must
807  * indicate their capabilities by setting the prot_capabilities using
808  * this call.
809  */
810 static inline void scsi_host_set_prot(struct Scsi_Host *shost, unsigned int mask)
811 {
812 	shost->prot_capabilities = mask;
813 }
814 
815 static inline unsigned int scsi_host_get_prot(struct Scsi_Host *shost)
816 {
817 	return shost->prot_capabilities;
818 }
819 
820 static inline int scsi_host_prot_dma(struct Scsi_Host *shost)
821 {
822 	return shost->prot_capabilities >= SHOST_DIX_TYPE0_PROTECTION;
823 }
824 
825 static inline unsigned int scsi_host_dif_capable(struct Scsi_Host *shost, unsigned int target_type)
826 {
827 	static unsigned char cap[] = { 0,
828 				       SHOST_DIF_TYPE1_PROTECTION,
829 				       SHOST_DIF_TYPE2_PROTECTION,
830 				       SHOST_DIF_TYPE3_PROTECTION };
831 
832 	if (target_type >= ARRAY_SIZE(cap))
833 		return 0;
834 
835 	return shost->prot_capabilities & cap[target_type] ? target_type : 0;
836 }
837 
838 static inline unsigned int scsi_host_dix_capable(struct Scsi_Host *shost, unsigned int target_type)
839 {
840 #if defined(CONFIG_BLK_DEV_INTEGRITY)
841 	static unsigned char cap[] = { SHOST_DIX_TYPE0_PROTECTION,
842 				       SHOST_DIX_TYPE1_PROTECTION,
843 				       SHOST_DIX_TYPE2_PROTECTION,
844 				       SHOST_DIX_TYPE3_PROTECTION };
845 
846 	if (target_type >= ARRAY_SIZE(cap))
847 		return 0;
848 
849 	return shost->prot_capabilities & cap[target_type];
850 #endif
851 	return 0;
852 }
853 
854 /*
855  * All DIX-capable initiators must support the T10-mandated CRC
856  * checksum.  Controllers can optionally implement the IP checksum
857  * scheme which has much lower impact on system performance.  Note
858  * that the main rationale for the checksum is to match integrity
859  * metadata with data.  Detecting bit errors are a job for ECC memory
860  * and buses.
861  */
862 
863 enum scsi_host_guard_type {
864 	SHOST_DIX_GUARD_CRC = 1 << 0,
865 	SHOST_DIX_GUARD_IP  = 1 << 1,
866 };
867 
868 static inline void scsi_host_set_guard(struct Scsi_Host *shost, unsigned char type)
869 {
870 	shost->prot_guard_type = type;
871 }
872 
873 static inline unsigned char scsi_host_get_guard(struct Scsi_Host *shost)
874 {
875 	return shost->prot_guard_type;
876 }
877 
878 extern int scsi_host_set_state(struct Scsi_Host *, enum scsi_host_state);
879 
880 #endif /* _SCSI_SCSI_HOST_H */
881