xref: /openbmc/linux/include/scsi/scsi_host.h (revision c819e2cf)
1 #ifndef _SCSI_SCSI_HOST_H
2 #define _SCSI_SCSI_HOST_H
3 
4 #include <linux/device.h>
5 #include <linux/list.h>
6 #include <linux/types.h>
7 #include <linux/workqueue.h>
8 #include <linux/mutex.h>
9 #include <linux/seq_file.h>
10 #include <linux/blk-mq.h>
11 #include <scsi/scsi.h>
12 
13 struct request_queue;
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 struct blk_queue_tags;
25 
26 
27 /*
28  * The various choices mean:
29  * NONE: Self evident.	Host adapter is not capable of scatter-gather.
30  * ALL:	 Means that the host adapter module can do scatter-gather,
31  *	 and that there is no limit to the size of the table to which
32  *	 we scatter/gather data.  The value we set here is the maximum
33  *	 single element sglist.  To use chained sglists, the adapter
34  *	 has to set a value beyond ALL (and correctly use the chain
35  *	 handling API.
36  * Anything else:  Indicates the maximum number of chains that can be
37  *	 used in one scatter-gather request.
38  */
39 #define SG_NONE 0
40 #define SG_ALL	SCSI_MAX_SG_SEGMENTS
41 
42 #define MODE_UNKNOWN 0x00
43 #define MODE_INITIATOR 0x01
44 #define MODE_TARGET 0x02
45 
46 #define DISABLE_CLUSTERING 0
47 #define ENABLE_CLUSTERING 1
48 
49 struct scsi_host_template {
50 	struct module *module;
51 	const char *name;
52 
53 	/*
54 	 * Used to initialize old-style drivers.  For new-style drivers
55 	 * just perform all work in your module initialization function.
56 	 *
57 	 * Status:  OBSOLETE
58 	 */
59 	int (* detect)(struct scsi_host_template *);
60 
61 	/*
62 	 * Used as unload callback for hosts with old-style drivers.
63 	 *
64 	 * Status: OBSOLETE
65 	 */
66 	int (* release)(struct Scsi_Host *);
67 
68 	/*
69 	 * The info function will return whatever useful information the
70 	 * developer sees fit.  If not provided, then the name field will
71 	 * be used instead.
72 	 *
73 	 * Status: OPTIONAL
74 	 */
75 	const char *(* info)(struct Scsi_Host *);
76 
77 	/*
78 	 * Ioctl interface
79 	 *
80 	 * Status: OPTIONAL
81 	 */
82 	int (* ioctl)(struct scsi_device *dev, int cmd, void __user *arg);
83 
84 
85 #ifdef CONFIG_COMPAT
86 	/*
87 	 * Compat handler. Handle 32bit ABI.
88 	 * When unknown ioctl is passed return -ENOIOCTLCMD.
89 	 *
90 	 * Status: OPTIONAL
91 	 */
92 	int (* compat_ioctl)(struct scsi_device *dev, int cmd, void __user *arg);
93 #endif
94 
95 	/*
96 	 * The queuecommand function is used to queue up a scsi
97 	 * command block to the LLDD.  When the driver finished
98 	 * processing the command the done callback is invoked.
99 	 *
100 	 * If queuecommand returns 0, then the HBA has accepted the
101 	 * command.  The done() function must be called on the command
102 	 * when the driver has finished with it. (you may call done on the
103 	 * command before queuecommand returns, but in this case you
104 	 * *must* return 0 from queuecommand).
105 	 *
106 	 * Queuecommand may also reject the command, in which case it may
107 	 * not touch the command and must not call done() for it.
108 	 *
109 	 * There are two possible rejection returns:
110 	 *
111 	 *   SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but
112 	 *   allow commands to other devices serviced by this host.
113 	 *
114 	 *   SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this
115 	 *   host temporarily.
116 	 *
117          * For compatibility, any other non-zero return is treated the
118          * same as SCSI_MLQUEUE_HOST_BUSY.
119 	 *
120 	 * NOTE: "temporarily" means either until the next command for#
121 	 * this device/host completes, or a period of time determined by
122 	 * I/O pressure in the system if there are no other outstanding
123 	 * commands.
124 	 *
125 	 * STATUS: REQUIRED
126 	 */
127 	int (* queuecommand)(struct Scsi_Host *, struct scsi_cmnd *);
128 
129 	/*
130 	 * This is an error handling strategy routine.  You don't need to
131 	 * define one of these if you don't want to - there is a default
132 	 * routine that is present that should work in most cases.  For those
133 	 * driver authors that have the inclination and ability to write their
134 	 * own strategy routine, this is where it is specified.  Note - the
135 	 * strategy routine is *ALWAYS* run in the context of the kernel eh
136 	 * thread.  Thus you are guaranteed to *NOT* be in an interrupt
137 	 * handler when you execute this, and you are also guaranteed to
138 	 * *NOT* have any other commands being queued while you are in the
139 	 * strategy routine. When you return from this function, operations
140 	 * return to normal.
141 	 *
142 	 * See scsi_error.c scsi_unjam_host for additional comments about
143 	 * what this function should and should not be attempting to do.
144 	 *
145 	 * Status: REQUIRED	(at least one of them)
146 	 */
147 	int (* eh_abort_handler)(struct scsi_cmnd *);
148 	int (* eh_device_reset_handler)(struct scsi_cmnd *);
149 	int (* eh_target_reset_handler)(struct scsi_cmnd *);
150 	int (* eh_bus_reset_handler)(struct scsi_cmnd *);
151 	int (* eh_host_reset_handler)(struct scsi_cmnd *);
152 
153 	/*
154 	 * Before the mid layer attempts to scan for a new device where none
155 	 * currently exists, it will call this entry in your driver.  Should
156 	 * your driver need to allocate any structs or perform any other init
157 	 * items in order to send commands to a currently unused target/lun
158 	 * combo, then this is where you can perform those allocations.  This
159 	 * is specifically so that drivers won't have to perform any kind of
160 	 * "is this a new device" checks in their queuecommand routine,
161 	 * thereby making the hot path a bit quicker.
162 	 *
163 	 * Return values: 0 on success, non-0 on failure
164 	 *
165 	 * Deallocation:  If we didn't find any devices at this ID, you will
166 	 * get an immediate call to slave_destroy().  If we find something
167 	 * here then you will get a call to slave_configure(), then the
168 	 * device will be used for however long it is kept around, then when
169 	 * the device is removed from the system (or * possibly at reboot
170 	 * time), you will then get a call to slave_destroy().  This is
171 	 * assuming you implement slave_configure and slave_destroy.
172 	 * However, if you allocate memory and hang it off the device struct,
173 	 * then you must implement the slave_destroy() routine at a minimum
174 	 * in order to avoid leaking memory
175 	 * each time a device is tore down.
176 	 *
177 	 * Status: OPTIONAL
178 	 */
179 	int (* slave_alloc)(struct scsi_device *);
180 
181 	/*
182 	 * Once the device has responded to an INQUIRY and we know the
183 	 * device is online, we call into the low level driver with the
184 	 * struct scsi_device *.  If the low level device driver implements
185 	 * this function, it *must* perform the task of setting the queue
186 	 * depth on the device.  All other tasks are optional and depend
187 	 * on what the driver supports and various implementation details.
188 	 *
189 	 * Things currently recommended to be handled at this time include:
190 	 *
191 	 * 1.  Setting the device queue depth.  Proper setting of this is
192 	 *     described in the comments for scsi_change_queue_depth.
193 	 * 2.  Determining if the device supports the various synchronous
194 	 *     negotiation protocols.  The device struct will already have
195 	 *     responded to INQUIRY and the results of the standard items
196 	 *     will have been shoved into the various device flag bits, eg.
197 	 *     device->sdtr will be true if the device supports SDTR messages.
198 	 * 3.  Allocating command structs that the device will need.
199 	 * 4.  Setting the default timeout on this device (if needed).
200 	 * 5.  Anything else the low level driver might want to do on a device
201 	 *     specific setup basis...
202 	 * 6.  Return 0 on success, non-0 on error.  The device will be marked
203 	 *     as offline on error so that no access will occur.  If you return
204 	 *     non-0, your slave_destroy routine will never get called for this
205 	 *     device, so don't leave any loose memory hanging around, clean
206 	 *     up after yourself before returning non-0
207 	 *
208 	 * Status: OPTIONAL
209 	 */
210 	int (* slave_configure)(struct scsi_device *);
211 
212 	/*
213 	 * Immediately prior to deallocating the device and after all activity
214 	 * has ceased the mid layer calls this point so that the low level
215 	 * driver may completely detach itself from the scsi device and vice
216 	 * versa.  The low level driver is responsible for freeing any memory
217 	 * it allocated in the slave_alloc or slave_configure calls.
218 	 *
219 	 * Status: OPTIONAL
220 	 */
221 	void (* slave_destroy)(struct scsi_device *);
222 
223 	/*
224 	 * Before the mid layer attempts to scan for a new device attached
225 	 * to a target where no target currently exists, it will call this
226 	 * entry in your driver.  Should your driver need to allocate any
227 	 * structs or perform any other init items in order to send commands
228 	 * to a currently unused target, then this is where you can perform
229 	 * those allocations.
230 	 *
231 	 * Return values: 0 on success, non-0 on failure
232 	 *
233 	 * Status: OPTIONAL
234 	 */
235 	int (* target_alloc)(struct scsi_target *);
236 
237 	/*
238 	 * Immediately prior to deallocating the target structure, and
239 	 * after all activity to attached scsi devices has ceased, the
240 	 * midlayer calls this point so that the driver may deallocate
241 	 * and terminate any references to the target.
242 	 *
243 	 * Status: OPTIONAL
244 	 */
245 	void (* target_destroy)(struct scsi_target *);
246 
247 	/*
248 	 * If a host has the ability to discover targets on its own instead
249 	 * of scanning the entire bus, it can fill in this function and
250 	 * call scsi_scan_host().  This function will be called periodically
251 	 * until it returns 1 with the scsi_host and the elapsed time of
252 	 * the scan in jiffies.
253 	 *
254 	 * Status: OPTIONAL
255 	 */
256 	int (* scan_finished)(struct Scsi_Host *, unsigned long);
257 
258 	/*
259 	 * If the host wants to be called before the scan starts, but
260 	 * after the midlayer has set up ready for the scan, it can fill
261 	 * in this function.
262 	 *
263 	 * Status: OPTIONAL
264 	 */
265 	void (* scan_start)(struct Scsi_Host *);
266 
267 	/*
268 	 * Fill in this function to allow the queue depth of this host
269 	 * to be changeable (on a per device basis).  Returns either
270 	 * the current queue depth setting (may be different from what
271 	 * was passed in) or an error.  An error should only be
272 	 * returned if the requested depth is legal but the driver was
273 	 * unable to set it.  If the requested depth is illegal, the
274 	 * driver should set and return the closest legal queue depth.
275 	 *
276 	 * Status: OPTIONAL
277 	 */
278 	int (* change_queue_depth)(struct scsi_device *, int);
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 	 * EH_HANDLED:		I fixed the error, please complete the command
314 	 * EH_RESET_TIMER:	I need more time, reset the timer and
315 	 *			begin counting again
316 	 * EH_NOT_HANDLED	Begin normal error recovery
317 	 *
318 	 * Status: OPTIONAL
319 	 */
320 	enum blk_eh_timer_return (*eh_timed_out)(struct scsi_cmnd *);
321 
322 	/* This is an optional routine that allows transport to initiate
323 	 * LLD adapter or firmware reset using sysfs attribute.
324 	 *
325 	 * Return values: 0 on success, -ve value on failure.
326 	 *
327 	 * Status: OPTIONAL
328 	 */
329 
330 	int (*host_reset)(struct Scsi_Host *shost, int reset_type);
331 #define SCSI_ADAPTER_RESET	1
332 #define SCSI_FIRMWARE_RESET	2
333 
334 
335 	/*
336 	 * Name of proc directory
337 	 */
338 	const char *proc_name;
339 
340 	/*
341 	 * Used to store the procfs directory if a driver implements the
342 	 * show_info method.
343 	 */
344 	struct proc_dir_entry *proc_dir;
345 
346 	/*
347 	 * This determines if we will use a non-interrupt driven
348 	 * or an interrupt driven scheme.  It is set to the maximum number
349 	 * of simultaneous commands a given host adapter will accept.
350 	 */
351 	int can_queue;
352 
353 	/*
354 	 * In many instances, especially where disconnect / reconnect are
355 	 * supported, our host also has an ID on the SCSI bus.  If this is
356 	 * the case, then it must be reserved.  Please set this_id to -1 if
357 	 * your setup is in single initiator mode, and the host lacks an
358 	 * ID.
359 	 */
360 	int this_id;
361 
362 	/*
363 	 * This determines the degree to which the host adapter is capable
364 	 * of scatter-gather.
365 	 */
366 	unsigned short sg_tablesize;
367 	unsigned short sg_prot_tablesize;
368 
369 	/*
370 	 * Set this if the host adapter has limitations beside segment count.
371 	 */
372 	unsigned int max_sectors;
373 
374 	/*
375 	 * DMA scatter gather segment boundary limit. A segment crossing this
376 	 * boundary will be split in two.
377 	 */
378 	unsigned long dma_boundary;
379 
380 	/*
381 	 * This specifies "machine infinity" for host templates which don't
382 	 * limit the transfer size.  Note this limit represents an absolute
383 	 * maximum, and may be over the transfer limits allowed for
384 	 * individual devices (e.g. 256 for SCSI-1).
385 	 */
386 #define SCSI_DEFAULT_MAX_SECTORS	1024
387 
388 	/*
389 	 * True if this host adapter can make good use of linked commands.
390 	 * This will allow more than one command to be queued to a given
391 	 * unit on a given host.  Set this to the maximum number of command
392 	 * blocks to be provided for each device.  Set this to 1 for one
393 	 * command block per lun, 2 for two, etc.  Do not set this to 0.
394 	 * You should make sure that the host adapter will do the right thing
395 	 * before you try setting this above 1.
396 	 */
397 	short cmd_per_lun;
398 
399 	/*
400 	 * present contains counter indicating how many boards of this
401 	 * type were found when we did the scan.
402 	 */
403 	unsigned char present;
404 
405 	/*
406 	 * Let the block layer assigns tags to all commands.
407 	 */
408 	unsigned use_blk_tags:1;
409 
410 	/*
411 	 * Track QUEUE_FULL events and reduce queue depth on demand.
412 	 */
413 	unsigned track_queue_depth:1;
414 
415 	/*
416 	 * This specifies the mode that a LLD supports.
417 	 */
418 	unsigned supported_mode:2;
419 
420 	/*
421 	 * True if this host adapter uses unchecked DMA onto an ISA bus.
422 	 */
423 	unsigned unchecked_isa_dma:1;
424 
425 	/*
426 	 * True if this host adapter can make good use of clustering.
427 	 * I originally thought that if the tablesize was large that it
428 	 * was a waste of CPU cycles to prepare a cluster list, but
429 	 * it works out that the Buslogic is faster if you use a smaller
430 	 * number of segments (i.e. use clustering).  I guess it is
431 	 * inefficient.
432 	 */
433 	unsigned use_clustering:1;
434 
435 	/*
436 	 * True for emulated SCSI host adapters (e.g. ATAPI).
437 	 */
438 	unsigned emulated:1;
439 
440 	/*
441 	 * True if the low-level driver performs its own reset-settle delays.
442 	 */
443 	unsigned skip_settle_delay:1;
444 
445 	/* True if the controller does not support WRITE SAME */
446 	unsigned no_write_same:1;
447 
448 	/*
449 	 * True if asynchronous aborts are not supported
450 	 */
451 	unsigned no_async_abort:1;
452 
453 	/*
454 	 * Countdown for host blocking with no commands outstanding.
455 	 */
456 	unsigned int max_host_blocked;
457 
458 	/*
459 	 * Default value for the blocking.  If the queue is empty,
460 	 * host_blocked counts down in the request_fn until it restarts
461 	 * host operations as zero is reached.
462 	 *
463 	 * FIXME: This should probably be a value in the template
464 	 */
465 #define SCSI_DEFAULT_HOST_BLOCKED	7
466 
467 	/*
468 	 * Pointer to the sysfs class properties for this host, NULL terminated.
469 	 */
470 	struct device_attribute **shost_attrs;
471 
472 	/*
473 	 * Pointer to the SCSI device properties for this host, NULL terminated.
474 	 */
475 	struct device_attribute **sdev_attrs;
476 
477 	/*
478 	 * List of hosts per template.
479 	 *
480 	 * This is only for use by scsi_module.c for legacy templates.
481 	 * For these access to it is synchronized implicitly by
482 	 * module_init/module_exit.
483 	 */
484 	struct list_head legacy_hosts;
485 
486 	/*
487 	 * Vendor Identifier associated with the host
488 	 *
489 	 * Note: When specifying vendor_id, be sure to read the
490 	 *   Vendor Type and ID formatting requirements specified in
491 	 *   scsi_netlink.h
492 	 */
493 	u64 vendor_id;
494 
495 	/*
496 	 * Additional per-command data allocated for the driver.
497 	 */
498 	unsigned int cmd_size;
499 	struct scsi_host_cmd_pool *cmd_pool;
500 
501 	/* temporary flag to disable blk-mq I/O path */
502 	bool disable_blk_mq;
503 };
504 
505 /*
506  * Temporary #define for host lock push down. Can be removed when all
507  * drivers have been updated to take advantage of unlocked
508  * queuecommand.
509  *
510  */
511 #define DEF_SCSI_QCMD(func_name) \
512 	int func_name(struct Scsi_Host *shost, struct scsi_cmnd *cmd)	\
513 	{								\
514 		unsigned long irq_flags;				\
515 		int rc;							\
516 		spin_lock_irqsave(shost->host_lock, irq_flags);		\
517 		scsi_cmd_get_serial(shost, cmd);			\
518 		rc = func_name##_lck (cmd, cmd->scsi_done);			\
519 		spin_unlock_irqrestore(shost->host_lock, irq_flags);	\
520 		return rc;						\
521 	}
522 
523 
524 /*
525  * shost state: If you alter this, you also need to alter scsi_sysfs.c
526  * (for the ascii descriptions) and the state model enforcer:
527  * scsi_host_set_state()
528  */
529 enum scsi_host_state {
530 	SHOST_CREATED = 1,
531 	SHOST_RUNNING,
532 	SHOST_CANCEL,
533 	SHOST_DEL,
534 	SHOST_RECOVERY,
535 	SHOST_CANCEL_RECOVERY,
536 	SHOST_DEL_RECOVERY,
537 };
538 
539 struct Scsi_Host {
540 	/*
541 	 * __devices is protected by the host_lock, but you should
542 	 * usually use scsi_device_lookup / shost_for_each_device
543 	 * to access it and don't care about locking yourself.
544 	 * In the rare case of being in irq context you can use
545 	 * their __ prefixed variants with the lock held. NEVER
546 	 * access this list directly from a driver.
547 	 */
548 	struct list_head	__devices;
549 	struct list_head	__targets;
550 
551 	struct scsi_host_cmd_pool *cmd_pool;
552 	spinlock_t		free_list_lock;
553 	struct list_head	free_list; /* backup store of cmd structs */
554 	struct list_head	starved_list;
555 
556 	spinlock_t		default_lock;
557 	spinlock_t		*host_lock;
558 
559 	struct mutex		scan_mutex;/* serialize scanning activity */
560 
561 	struct list_head	eh_cmd_q;
562 	struct task_struct    * ehandler;  /* Error recovery thread. */
563 	struct completion     * eh_action; /* Wait for specific actions on the
564 					      host. */
565 	wait_queue_head_t       host_wait;
566 	struct scsi_host_template *hostt;
567 	struct scsi_transport_template *transportt;
568 
569 	/*
570 	 * Area to keep a shared tag map (if needed, will be
571 	 * NULL if not).
572 	 */
573 	union {
574 		struct blk_queue_tag	*bqt;
575 		struct blk_mq_tag_set	tag_set;
576 	};
577 
578 	atomic_t host_busy;		   /* commands actually active on low-level */
579 	atomic_t host_blocked;
580 
581 	unsigned int host_failed;	   /* commands that failed.
582 					      protected by host_lock */
583 	unsigned int host_eh_scheduled;    /* EH scheduled without command */
584 
585 	unsigned int host_no;  /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
586 
587 	/* next two fields are used to bound the time spent in error handling */
588 	int eh_deadline;
589 	unsigned long last_reset;
590 
591 
592 	/*
593 	 * These three parameters can be used to allow for wide scsi,
594 	 * and for host adapters that support multiple busses
595 	 * The last two should be set to 1 more than the actual max id
596 	 * or lun (e.g. 8 for SCSI parallel systems).
597 	 */
598 	unsigned int max_channel;
599 	unsigned int max_id;
600 	u64 max_lun;
601 
602 	/*
603 	 * This is a unique identifier that must be assigned so that we
604 	 * have some way of identifying each detected host adapter properly
605 	 * and uniquely.  For hosts that do not support more than one card
606 	 * in the system at one time, this does not need to be set.  It is
607 	 * initialized to 0 in scsi_register.
608 	 */
609 	unsigned int unique_id;
610 
611 	/*
612 	 * The maximum length of SCSI commands that this host can accept.
613 	 * Probably 12 for most host adapters, but could be 16 for others.
614 	 * or 260 if the driver supports variable length cdbs.
615 	 * For drivers that don't set this field, a value of 12 is
616 	 * assumed.
617 	 */
618 	unsigned short max_cmd_len;
619 
620 	int this_id;
621 	int can_queue;
622 	short cmd_per_lun;
623 	short unsigned int sg_tablesize;
624 	short unsigned int sg_prot_tablesize;
625 	unsigned int max_sectors;
626 	unsigned long dma_boundary;
627 	/*
628 	 * In scsi-mq mode, the number of hardware queues supported by the LLD.
629 	 *
630 	 * Note: it is assumed that each hardware queue has a queue depth of
631 	 * can_queue. In other words, the total queue depth per host
632 	 * is nr_hw_queues * can_queue.
633 	 */
634 	unsigned nr_hw_queues;
635 	/*
636 	 * Used to assign serial numbers to the cmds.
637 	 * Protected by the host lock.
638 	 */
639 	unsigned long cmd_serial_number;
640 
641 	unsigned active_mode:2;
642 	unsigned unchecked_isa_dma:1;
643 	unsigned use_clustering:1;
644 
645 	/*
646 	 * Host has requested that no further requests come through for the
647 	 * time being.
648 	 */
649 	unsigned host_self_blocked:1;
650 
651 	/*
652 	 * Host uses correct SCSI ordering not PC ordering. The bit is
653 	 * set for the minority of drivers whose authors actually read
654 	 * the spec ;).
655 	 */
656 	unsigned reverse_ordering:1;
657 
658 	/* Task mgmt function in progress */
659 	unsigned tmf_in_progress:1;
660 
661 	/* Asynchronous scan in progress */
662 	unsigned async_scan:1;
663 
664 	/* Don't resume host in EH */
665 	unsigned eh_noresume:1;
666 
667 	/* The controller does not support WRITE SAME */
668 	unsigned no_write_same:1;
669 
670 	unsigned use_blk_mq:1;
671 	unsigned use_cmd_list:1;
672 
673 	/*
674 	 * Optional work queue to be utilized by the transport
675 	 */
676 	char work_q_name[20];
677 	struct workqueue_struct *work_q;
678 
679 	/*
680 	 * Task management function work queue
681 	 */
682 	struct workqueue_struct *tmf_work_q;
683 
684 	/* The transport requires the LUN bits NOT to be stored in CDB[1] */
685 	unsigned no_scsi2_lun_in_cdb:1;
686 
687 	/*
688 	 * Value host_blocked counts down from
689 	 */
690 	unsigned int max_host_blocked;
691 
692 	/* Protection Information */
693 	unsigned int prot_capabilities;
694 	unsigned char prot_guard_type;
695 
696 	/*
697 	 * q used for scsi_tgt msgs, async events or any other requests that
698 	 * need to be processed in userspace
699 	 */
700 	struct request_queue *uspace_req_q;
701 
702 	/* legacy crap */
703 	unsigned long base;
704 	unsigned long io_port;
705 	unsigned char n_io_port;
706 	unsigned char dma_channel;
707 	unsigned int  irq;
708 
709 
710 	enum scsi_host_state shost_state;
711 
712 	/* ldm bits */
713 	struct device		shost_gendev, shost_dev;
714 
715 	/*
716 	 * List of hosts per template.
717 	 *
718 	 * This is only for use by scsi_module.c for legacy templates.
719 	 * For these access to it is synchronized implicitly by
720 	 * module_init/module_exit.
721 	 */
722 	struct list_head sht_legacy_list;
723 
724 	/*
725 	 * Points to the transport data (if any) which is allocated
726 	 * separately
727 	 */
728 	void *shost_data;
729 
730 	/*
731 	 * Points to the physical bus device we'd use to do DMA
732 	 * Needed just in case we have virtual hosts.
733 	 */
734 	struct device *dma_dev;
735 
736 	/*
737 	 * We should ensure that this is aligned, both for better performance
738 	 * and also because some compilers (m68k) don't automatically force
739 	 * alignment to a long boundary.
740 	 */
741 	unsigned long hostdata[0]  /* Used for storage of host specific stuff */
742 		__attribute__ ((aligned (sizeof(unsigned long))));
743 };
744 
745 #define		class_to_shost(d)	\
746 	container_of(d, struct Scsi_Host, shost_dev)
747 
748 #define shost_printk(prefix, shost, fmt, a...)	\
749 	dev_printk(prefix, &(shost)->shost_gendev, fmt, ##a)
750 
751 static inline void *shost_priv(struct Scsi_Host *shost)
752 {
753 	return (void *)shost->hostdata;
754 }
755 
756 int scsi_is_host_device(const struct device *);
757 
758 static inline struct Scsi_Host *dev_to_shost(struct device *dev)
759 {
760 	while (!scsi_is_host_device(dev)) {
761 		if (!dev->parent)
762 			return NULL;
763 		dev = dev->parent;
764 	}
765 	return container_of(dev, struct Scsi_Host, shost_gendev);
766 }
767 
768 static inline int scsi_host_in_recovery(struct Scsi_Host *shost)
769 {
770 	return shost->shost_state == SHOST_RECOVERY ||
771 		shost->shost_state == SHOST_CANCEL_RECOVERY ||
772 		shost->shost_state == SHOST_DEL_RECOVERY ||
773 		shost->tmf_in_progress;
774 }
775 
776 extern bool scsi_use_blk_mq;
777 
778 static inline bool shost_use_blk_mq(struct Scsi_Host *shost)
779 {
780 	return shost->use_blk_mq;
781 }
782 
783 extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *);
784 extern void scsi_flush_work(struct Scsi_Host *);
785 
786 extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int);
787 extern int __must_check scsi_add_host_with_dma(struct Scsi_Host *,
788 					       struct device *,
789 					       struct device *);
790 extern void scsi_scan_host(struct Scsi_Host *);
791 extern void scsi_rescan_device(struct device *);
792 extern void scsi_remove_host(struct Scsi_Host *);
793 extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);
794 extern void scsi_host_put(struct Scsi_Host *t);
795 extern struct Scsi_Host *scsi_host_lookup(unsigned short);
796 extern const char *scsi_host_state_name(enum scsi_host_state);
797 extern void scsi_cmd_get_serial(struct Scsi_Host *, struct scsi_cmnd *);
798 
799 static inline int __must_check scsi_add_host(struct Scsi_Host *host,
800 					     struct device *dev)
801 {
802 	return scsi_add_host_with_dma(host, dev, dev);
803 }
804 
805 static inline struct device *scsi_get_device(struct Scsi_Host *shost)
806 {
807         return shost->shost_gendev.parent;
808 }
809 
810 /**
811  * scsi_host_scan_allowed - Is scanning of this host allowed
812  * @shost:	Pointer to Scsi_Host.
813  **/
814 static inline int scsi_host_scan_allowed(struct Scsi_Host *shost)
815 {
816 	return shost->shost_state == SHOST_RUNNING ||
817 	       shost->shost_state == SHOST_RECOVERY;
818 }
819 
820 extern void scsi_unblock_requests(struct Scsi_Host *);
821 extern void scsi_block_requests(struct Scsi_Host *);
822 
823 struct class_container;
824 
825 extern struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
826 						void (*) (struct request_queue *));
827 /*
828  * These two functions are used to allocate and free a pseudo device
829  * which will connect to the host adapter itself rather than any
830  * physical device.  You must deallocate when you are done with the
831  * thing.  This physical pseudo-device isn't real and won't be available
832  * from any high-level drivers.
833  */
834 extern void scsi_free_host_dev(struct scsi_device *);
835 extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *);
836 
837 /*
838  * DIF defines the exchange of protection information between
839  * initiator and SBC block device.
840  *
841  * DIX defines the exchange of protection information between OS and
842  * initiator.
843  */
844 enum scsi_host_prot_capabilities {
845 	SHOST_DIF_TYPE1_PROTECTION = 1 << 0, /* T10 DIF Type 1 */
846 	SHOST_DIF_TYPE2_PROTECTION = 1 << 1, /* T10 DIF Type 2 */
847 	SHOST_DIF_TYPE3_PROTECTION = 1 << 2, /* T10 DIF Type 3 */
848 
849 	SHOST_DIX_TYPE0_PROTECTION = 1 << 3, /* DIX between OS and HBA only */
850 	SHOST_DIX_TYPE1_PROTECTION = 1 << 4, /* DIX with DIF Type 1 */
851 	SHOST_DIX_TYPE2_PROTECTION = 1 << 5, /* DIX with DIF Type 2 */
852 	SHOST_DIX_TYPE3_PROTECTION = 1 << 6, /* DIX with DIF Type 3 */
853 };
854 
855 /*
856  * SCSI hosts which support the Data Integrity Extensions must
857  * indicate their capabilities by setting the prot_capabilities using
858  * this call.
859  */
860 static inline void scsi_host_set_prot(struct Scsi_Host *shost, unsigned int mask)
861 {
862 	shost->prot_capabilities = mask;
863 }
864 
865 static inline unsigned int scsi_host_get_prot(struct Scsi_Host *shost)
866 {
867 	return shost->prot_capabilities;
868 }
869 
870 static inline int scsi_host_prot_dma(struct Scsi_Host *shost)
871 {
872 	return shost->prot_capabilities >= SHOST_DIX_TYPE0_PROTECTION;
873 }
874 
875 static inline unsigned int scsi_host_dif_capable(struct Scsi_Host *shost, unsigned int target_type)
876 {
877 	static unsigned char cap[] = { 0,
878 				       SHOST_DIF_TYPE1_PROTECTION,
879 				       SHOST_DIF_TYPE2_PROTECTION,
880 				       SHOST_DIF_TYPE3_PROTECTION };
881 
882 	if (target_type >= ARRAY_SIZE(cap))
883 		return 0;
884 
885 	return shost->prot_capabilities & cap[target_type] ? target_type : 0;
886 }
887 
888 static inline unsigned int scsi_host_dix_capable(struct Scsi_Host *shost, unsigned int target_type)
889 {
890 #if defined(CONFIG_BLK_DEV_INTEGRITY)
891 	static unsigned char cap[] = { SHOST_DIX_TYPE0_PROTECTION,
892 				       SHOST_DIX_TYPE1_PROTECTION,
893 				       SHOST_DIX_TYPE2_PROTECTION,
894 				       SHOST_DIX_TYPE3_PROTECTION };
895 
896 	if (target_type >= ARRAY_SIZE(cap))
897 		return 0;
898 
899 	return shost->prot_capabilities & cap[target_type];
900 #endif
901 	return 0;
902 }
903 
904 /*
905  * All DIX-capable initiators must support the T10-mandated CRC
906  * checksum.  Controllers can optionally implement the IP checksum
907  * scheme which has much lower impact on system performance.  Note
908  * that the main rationale for the checksum is to match integrity
909  * metadata with data.  Detecting bit errors are a job for ECC memory
910  * and buses.
911  */
912 
913 enum scsi_host_guard_type {
914 	SHOST_DIX_GUARD_CRC = 1 << 0,
915 	SHOST_DIX_GUARD_IP  = 1 << 1,
916 };
917 
918 static inline void scsi_host_set_guard(struct Scsi_Host *shost, unsigned char type)
919 {
920 	shost->prot_guard_type = type;
921 }
922 
923 static inline unsigned char scsi_host_get_guard(struct Scsi_Host *shost)
924 {
925 	return shost->prot_guard_type;
926 }
927 
928 /* legacy interfaces */
929 extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int);
930 extern void scsi_unregister(struct Scsi_Host *);
931 extern int scsi_host_set_state(struct Scsi_Host *, enum scsi_host_state);
932 
933 #endif /* _SCSI_SCSI_HOST_H */
934