scsi_host.h

  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
 14struct block_device;
 15struct completion;
 16struct module;
 17struct scsi_cmnd;
 18struct scsi_device;
 19struct scsi_target;
 20struct Scsi_Host;
 21struct scsi_transport_template;
 22
 23
 24#define SG_ALL	SG_CHUNK_SIZE
 25
 26#define MODE_UNKNOWN 0x00
 27#define MODE_INITIATOR 0x01
 28#define MODE_TARGET 0x02
 29
 30/**
 31 * enum scsi_timeout_action - How to handle a command that timed out.
 32 * @SCSI_EH_DONE: The command has already been completed.
 33 * @SCSI_EH_RESET_TIMER: Reset the timer and continue waiting for completion.
 34 * @SCSI_EH_NOT_HANDLED: The command has not yet finished. Abort the command.
 35 */
 36enum scsi_timeout_action {
 37	SCSI_EH_DONE,
 38	SCSI_EH_RESET_TIMER,
 39	SCSI_EH_NOT_HANDLED,
 40};
 41
 42struct scsi_host_template {
 43	/*
 44	 * Put fields referenced in IO submission path together in
 45	 * same cacheline
 46	 */
 47
 48	/*
 49	 * Additional per-command data allocated for the driver.
 50	 */
 51	unsigned int cmd_size;
 52
 53	/*
 54	 * The queuecommand function is used to queue up a scsi
 55	 * command block to the LLDD.  When the driver finished
 56	 * processing the command the done callback is invoked.
 57	 *
 58	 * If queuecommand returns 0, then the driver has accepted the
 59	 * command.  It must also push it to the HBA if the scsi_cmnd
 60	 * flag SCMD_LAST is set, or if the driver does not implement
 61	 * commit_rqs.  The done() function must be called on the command
 62	 * when the driver has finished with it. (you may call done on the
 63	 * command before queuecommand returns, but in this case you
 64	 * *must* return 0 from queuecommand).
 65	 *
 66	 * Queuecommand may also reject the command, in which case it may
 67	 * not touch the command and must not call done() for it.
 68	 *
 69	 * There are two possible rejection returns:
 70	 *
 71	 *   SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but
 72	 *   allow commands to other devices serviced by this host.
 73	 *
 74	 *   SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this
 75	 *   host temporarily.
 76	 *
 77         * For compatibility, any other non-zero return is treated the
 78         * same as SCSI_MLQUEUE_HOST_BUSY.
 79	 *
 80	 * NOTE: "temporarily" means either until the next command for#
 81	 * this device/host completes, or a period of time determined by
 82	 * I/O pressure in the system if there are no other outstanding
 83	 * commands.
 84	 *
 85	 * STATUS: REQUIRED
 86	 */
 87	int (* queuecommand)(struct Scsi_Host *, struct scsi_cmnd *);
 88
 89	/*
 90	 * Queue a reserved command (BLK_MQ_REQ_RESERVED). The .queuecommand()
 91	 * documentation also applies to the .queue_reserved_command() callback.
 92	 */
 93	int (*queue_reserved_command)(struct Scsi_Host *, struct scsi_cmnd *);
 94
 95	/*
 96	 * The commit_rqs function is used to trigger a hardware
 97	 * doorbell after some requests have been queued with
 98	 * queuecommand, when an error is encountered before sending
 99	 * the request with SCMD_LAST set.
100	 *
101	 * STATUS: OPTIONAL
102	 */
103	void (*commit_rqs)(struct Scsi_Host *, u16);
104
105	struct module *module;
106	const char *name;
107
108	/*
109	 * The info function will return whatever useful information the
110	 * developer sees fit.  If not provided, then the name field will
111	 * be used instead.
112	 *
113	 * Status: OPTIONAL
114	 */
115	const char *(*info)(struct Scsi_Host *);
116
117	/*
118	 * Ioctl interface
119	 *
120	 * Status: OPTIONAL
121	 */
122	int (*ioctl)(struct scsi_device *dev, unsigned int cmd,
123		     void __user *arg);
124
125
126#ifdef CONFIG_COMPAT
127	/*
128	 * Compat handler. Handle 32bit ABI.
129	 * When unknown ioctl is passed return -ENOIOCTLCMD.
130	 *
131	 * Status: OPTIONAL
132	 */
133	int (*compat_ioctl)(struct scsi_device *dev, unsigned int cmd,
134			    void __user *arg);
135#endif
136
137	int (*init_cmd_priv)(struct Scsi_Host *shost, struct scsi_cmnd *cmd);
138	int (*exit_cmd_priv)(struct Scsi_Host *shost, struct scsi_cmnd *cmd);
139
140	/*
141	 * This is an error handling strategy routine.  You don't need to
142	 * define one of these if you don't want to - there is a default
143	 * routine that is present that should work in most cases.  For those
144	 * driver authors that have the inclination and ability to write their
145	 * own strategy routine, this is where it is specified.  Note - the
146	 * strategy routine is *ALWAYS* run in the context of the kernel eh
147	 * thread.  Thus you are guaranteed to *NOT* be in an interrupt
148	 * handler when you execute this, and you are also guaranteed to
149	 * *NOT* have any other commands being queued while you are in the
150	 * strategy routine. When you return from this function, operations
151	 * return to normal.
152	 *
153	 * See scsi_error.c scsi_unjam_host for additional comments about
154	 * what this function should and should not be attempting to do.
155	 *
156	 * Status: REQUIRED	(at least one of them)
157	 */
158	int (* eh_abort_handler)(struct scsi_cmnd *);
159	int (* eh_device_reset_handler)(struct scsi_cmnd *);
160	int (* eh_target_reset_handler)(struct scsi_cmnd *);
161	int (* eh_bus_reset_handler)(struct scsi_cmnd *);
162	int (* eh_host_reset_handler)(struct scsi_cmnd *);
163
164	/*
165	 * Before the mid layer attempts to scan for a new device where none
166	 * currently exists, it will call this entry in your driver.  Should
167	 * your driver need to allocate any structs or perform any other init
168	 * items in order to send commands to a currently unused target/lun
169	 * combo, then this is where you can perform those allocations.  This
170	 * is specifically so that drivers won't have to perform any kind of
171	 * "is this a new device" checks in their queuecommand routine,
172	 * thereby making the hot path a bit quicker.
173	 *
174	 * Return values: 0 on success, non-0 on failure
175	 *
176	 * Deallocation:  If we didn't find any devices at this ID, you will
177	 * get an immediate call to sdev_destroy().  If we find something
178	 * here then you will get a call to sdev_configure(), then the
179	 * device will be used for however long it is kept around, then when
180	 * the device is removed from the system (or * possibly at reboot
181	 * time), you will then get a call to sdev_destroy().  This is
182	 * assuming you implement sdev_configure and sdev_destroy.
183	 * However, if you allocate memory and hang it off the device struct,
184	 * then you must implement the sdev_destroy() routine at a minimum
185	 * in order to avoid leaking memory
186	 * each time a device is tore down.
187	 *
188	 * Status: OPTIONAL
189	 */
190	int (* sdev_init)(struct scsi_device *);
191
192	/*
193	 * Once the device has responded to an INQUIRY and we know the
194	 * device is online, we call into the low level driver with the
195	 * struct scsi_device *.  If the low level device driver implements
196	 * this function, it *must* perform the task of setting the queue
197	 * depth on the device.  All other tasks are optional and depend
198	 * on what the driver supports and various implementation details.
199	 * 
200	 * Things currently recommended to be handled at this time include:
201	 *
202	 * 1.  Setting the device queue depth.  Proper setting of this is
203	 *     described in the comments for scsi_change_queue_depth.
204	 * 2.  Determining if the device supports the various synchronous
205	 *     negotiation protocols.  The device struct will already have
206	 *     responded to INQUIRY and the results of the standard items
207	 *     will have been shoved into the various device flag bits, eg.
208	 *     device->sdtr will be true if the device supports SDTR messages.
209	 * 3.  Allocating command structs that the device will need.
210	 * 4.  Setting the default timeout on this device (if needed).
211	 * 5.  Anything else the low level driver might want to do on a device
212	 *     specific setup basis...
213	 * 6.  Return 0 on success, non-0 on error.  The device will be marked
214	 *     as offline on error so that no access will occur.  If you return
215	 *     non-0, your sdev_destroy routine will never get called for this
216	 *     device, so don't leave any loose memory hanging around, clean
217	 *     up after yourself before returning non-0
218	 *
219	 * Status: OPTIONAL
220	 */
221	int (* sdev_configure)(struct scsi_device *, struct queue_limits *lim);
222
223	/*
224	 * Immediately prior to deallocating the device and after all activity
225	 * has ceased the mid layer calls this point so that the low level
226	 * driver may completely detach itself from the scsi device and vice
227	 * versa.  The low level driver is responsible for freeing any memory
228	 * it allocated in the sdev_init or sdev_configure calls.
229	 *
230	 * Status: OPTIONAL
231	 */
232	void (* sdev_destroy)(struct scsi_device *);
233
234	/*
235	 * Before the mid layer attempts to scan for a new device attached
236	 * to a target where no target currently exists, it will call this
237	 * entry in your driver.  Should your driver need to allocate any
238	 * structs or perform any other init items in order to send commands
239	 * to a currently unused target, then this is where you can perform
240	 * those allocations.
241	 *
242	 * Return values: 0 on success, non-0 on failure
243	 *
244	 * Status: OPTIONAL
245	 */
246	int (* target_alloc)(struct scsi_target *);
247
248	/*
249	 * Immediately prior to deallocating the target structure, and
250	 * after all activity to attached scsi devices has ceased, the
251	 * midlayer calls this point so that the driver may deallocate
252	 * and terminate any references to the target.
253	 *
254	 * Note: This callback is called with the host lock held and hence
255	 * must not sleep.
256	 *
257	 * Status: OPTIONAL
258	 */
259	void (* target_destroy)(struct scsi_target *);
260
261	/*
262	 * If a host has the ability to discover targets on its own instead
263	 * of scanning the entire bus, it can fill in this function and
264	 * call scsi_scan_host().  This function will be called periodically
265	 * until it returns 1 with the scsi_host and the elapsed time of
266	 * the scan in jiffies.
267	 *
268	 * Status: OPTIONAL
269	 */
270	int (* scan_finished)(struct Scsi_Host *, unsigned long);
271
272	/*
273	 * If the host wants to be called before the scan starts, but
274	 * after the midlayer has set up ready for the scan, it can fill
275	 * in this function.
276	 *
277	 * Status: OPTIONAL
278	 */
279	void (* scan_start)(struct Scsi_Host *);
280
281	/*
282	 * Fill in this function to allow the queue depth of this host
283	 * to be changeable (on a per device basis).  Returns either
284	 * the current queue depth setting (may be different from what
285	 * was passed in) or an error.  An error should only be
286	 * returned if the requested depth is legal but the driver was
287	 * unable to set it.  If the requested depth is illegal, the
288	 * driver should set and return the closest legal queue depth.
289	 *
290	 * Status: OPTIONAL
291	 */
292	int (* change_queue_depth)(struct scsi_device *, int);
293
294	/*
295	 * This functions lets the driver expose the queue mapping
296	 * to the block layer.
297	 *
298	 * Status: OPTIONAL
299	 */
300	void (* map_queues)(struct Scsi_Host *shost);
301
302	/*
303	 * SCSI interface of blk_poll - poll for IO completions.
304	 * Only applicable if SCSI LLD exposes multiple h/w queues.
305	 *
306	 * Return value: Number of completed entries found.
307	 *
308	 * Status: OPTIONAL
309	 */
310	int (* mq_poll)(struct Scsi_Host *shost, unsigned int queue_num);
311
312	/*
313	 * Check if scatterlists need to be padded for DMA draining.
314	 *
315	 * Status: OPTIONAL
316	 */
317	bool (* dma_need_drain)(struct request *rq);
318
319	/*
320	 * This function determines the BIOS parameters for a given
321	 * harddisk.  These tend to be numbers that are made up by
322	 * the host adapter.  Parameters:
323	 * size, device, list (heads, sectors, cylinders)
324	 *
325	 * Status: OPTIONAL
326	 */
327	int (* bios_param)(struct scsi_device *, struct gendisk *,
328			sector_t, int []);
329
330	/*
331	 * This function is called when one or more partitions on the
332	 * device reach beyond the end of the device.
333	 *
334	 * Status: OPTIONAL
335	 */
336	void (*unlock_native_capacity)(struct scsi_device *);
337
338	/*
339	 * Can be used to export driver statistics and other infos to the
340	 * world outside the kernel ie. userspace and it also provides an
341	 * interface to feed the driver with information.
342	 *
343	 * Status: OBSOLETE
344	 */
345	int (*show_info)(struct seq_file *, struct Scsi_Host *);
346	int (*write_info)(struct Scsi_Host *, char *, int);
347
348	/*
349	 * This is an optional routine that allows the transport to become
350	 * involved when a scsi io timer fires. The return value tells the
351	 * timer routine how to finish the io timeout handling.
352	 *
353	 * Status: OPTIONAL
354	 */
355	enum scsi_timeout_action (*eh_timed_out)(struct scsi_cmnd *);
356	/*
357	 * Optional routine that allows the transport to decide if a cmd
358	 * is retryable. Return true if the transport is in a state the
359	 * cmd should be retried on.
360	 */
361	bool (*eh_should_retry_cmd)(struct scsi_cmnd *scmd);
362
363	/* This is an optional routine that allows transport to initiate
364	 * LLD adapter or firmware reset using sysfs attribute.
365	 *
366	 * Return values: 0 on success, -ve value on failure.
367	 *
368	 * Status: OPTIONAL
369	 */
370
371	int (*host_reset)(struct Scsi_Host *shost, int reset_type);
372#define SCSI_ADAPTER_RESET	1
373#define SCSI_FIRMWARE_RESET	2
374
375
376	/*
377	 * Name of proc directory
378	 */
379	const char *proc_name;
380
381	/*
382	 * This determines if we will use a non-interrupt driven
383	 * or an interrupt driven scheme.  It is set to the maximum number
384	 * of simultaneous commands a single hw queue in HBA will accept
385	 * excluding internal commands.
386	 */
387	int can_queue;
388
389	/*
390	 * This determines how many commands the HBA will set aside
391	 * for internal commands. This number will be added to
392	 * @can_queue to calculate the maximum number of simultaneous
393	 * commands sent to the host.
394	 */
395	int nr_reserved_cmds;
396
397	/*
398	 * In many instances, especially where disconnect / reconnect are
399	 * supported, our host also has an ID on the SCSI bus.  If this is
400	 * the case, then it must be reserved.  Please set this_id to -1 if
401	 * your setup is in single initiator mode, and the host lacks an
402	 * ID.
403	 */
404	int this_id;
405
406	/*
407	 * This determines the degree to which the host adapter is capable
408	 * of scatter-gather.
409	 */
410	unsigned short sg_tablesize;
411	unsigned short sg_prot_tablesize;
412
413	/*
414	 * Set this if the host adapter has limitations beside segment count.
415	 */
416	unsigned int max_sectors;
417
418	/*
419	 * Maximum size in bytes of a single segment.
420	 */
421	unsigned int max_segment_size;
422
423	unsigned int dma_alignment;
424
425	/*
426	 * DMA scatter gather segment boundary limit. A segment crossing this
427	 * boundary will be split in two.
428	 */
429	unsigned long dma_boundary;
430
431	unsigned long virt_boundary_mask;
432
433	/*
434	 * This specifies "machine infinity" for host templates which don't
435	 * limit the transfer size.  Note this limit represents an absolute
436	 * maximum, and may be over the transfer limits allowed for
437	 * individual devices (e.g. 256 for SCSI-1).
438	 */
439#define SCSI_DEFAULT_MAX_SECTORS	1024
440
441	/*
442	 * True if this host adapter can make good use of linked commands.
443	 * This will allow more than one command to be queued to a given
444	 * unit on a given host.  Set this to the maximum number of command
445	 * blocks to be provided for each device.  Set this to 1 for one
446	 * command block per lun, 2 for two, etc.  Do not set this to 0.
447	 * You should make sure that the host adapter will do the right thing
448	 * before you try setting this above 1.
449	 */
450	short cmd_per_lun;
451
452	/*
453	 * Allocate tags starting from last allocated tag.
454	 */
455	bool tag_alloc_policy_rr : 1;
456
457	/*
458	 * Track QUEUE_FULL events and reduce queue depth on demand.
459	 */
460	unsigned track_queue_depth:1;
461
462	/*
463	 * This specifies the mode that a LLD supports.
464	 */
465	unsigned supported_mode:2;
466
467	/*
468	 * True for emulated SCSI host adapters (e.g. ATAPI).
469	 */
470	unsigned emulated:1;
471
472	/*
473	 * True if the low-level driver performs its own reset-settle delays.
474	 */
475	unsigned skip_settle_delay:1;
476
477	/* True if the controller does not support WRITE SAME */
478	unsigned no_write_same:1;
479
480	/* True if the host uses host-wide tagspace */
481	unsigned host_tagset:1;
482
483	/* The queuecommand callback may block. See also BLK_MQ_F_BLOCKING. */
484	unsigned queuecommand_may_block:1;
485
486	/*
487	 * Countdown for host blocking with no commands outstanding.
488	 */
489	unsigned int max_host_blocked;
490
491	/*
492	 * Default value for the blocking.  If the queue is empty,
493	 * host_blocked counts down in the request_fn until it restarts
494	 * host operations as zero is reached.  
495	 *
496	 * FIXME: This should probably be a value in the template
497	 */
498#define SCSI_DEFAULT_HOST_BLOCKED	7
499
500	/*
501	 * Pointer to the SCSI host sysfs attribute groups, NULL terminated.
502	 */
503	const struct attribute_group **shost_groups;
504
505	/*
506	 * Pointer to the SCSI device attribute groups for this host,
507	 * NULL terminated.
508	 */
509	const struct attribute_group **sdev_groups;
510
511	/*
512	 * Vendor Identifier associated with the host
513	 *
514	 * Note: When specifying vendor_id, be sure to read the
515	 *   Vendor Type and ID formatting requirements specified in
516	 *   scsi_netlink.h
517	 */
518	u64 vendor_id;
519};
520
521/*
522 * Temporary #define for host lock push down. Can be removed when all
523 * drivers have been updated to take advantage of unlocked
524 * queuecommand.
525 *
526 */
527#define DEF_SCSI_QCMD(func_name) \
528	int func_name(struct Scsi_Host *shost, struct scsi_cmnd *cmd)	\
529	{								\
530		unsigned long irq_flags;				\
531		int rc;							\
532		spin_lock_irqsave(shost->host_lock, irq_flags);		\
533		rc = func_name##_lck(cmd);				\
534		spin_unlock_irqrestore(shost->host_lock, irq_flags);	\
535		return rc;						\
536	}
537
538
539/*
540 * shost state: If you alter this, you also need to alter scsi_sysfs.c
541 * (for the ascii descriptions) and the state model enforcer:
542 * scsi_host_set_state()
543 */
544enum scsi_host_state {
545	SHOST_CREATED = 1,
546	SHOST_RUNNING,
547	SHOST_CANCEL,
548	SHOST_DEL,
549	SHOST_RECOVERY,
550	SHOST_CANCEL_RECOVERY,
551	SHOST_DEL_RECOVERY,
552};
553
554struct Scsi_Host {
555	/*
556	 * __devices is protected by the host_lock, but you should
557	 * usually use scsi_device_lookup / shost_for_each_device
558	 * to access it and don't care about locking yourself.
559	 * In the rare case of being in irq context you can use
560	 * their __ prefixed variants with the lock held. NEVER
561	 * access this list directly from a driver.
562	 */
563	struct list_head	__devices;
564	struct list_head	__targets;
565	
566	struct list_head	starved_list;
567
568	spinlock_t		default_lock;
569	spinlock_t		*host_lock;
570
571	struct mutex		scan_mutex;/* serialize scanning activity */
572
573	struct list_head	eh_abort_list;
574	struct list_head	eh_cmd_q;
575	struct task_struct    * ehandler;  /* Error recovery thread. */
576	struct completion     * eh_action; /* Wait for specific actions on the
577					      host. */
578	wait_queue_head_t       host_wait;
579	const struct scsi_host_template *hostt;
580	struct scsi_transport_template *transportt;
581
582	struct kref		tagset_refcnt;
583	struct completion	tagset_freed;
584	/* Area to keep a shared tag map */
585	struct blk_mq_tag_set	tag_set;
586
587	atomic_t host_blocked;
588
589	unsigned int host_failed;	   /* commands that failed.
590					      protected by host_lock */
591	unsigned int host_eh_scheduled;    /* EH scheduled without command */
592    
593	unsigned int host_no;  /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
594
595	/* next two fields are used to bound the time spent in error handling */
596	int eh_deadline;
597	unsigned long last_reset;
598
599
600	/*
601	 * These three parameters can be used to allow for wide scsi,
602	 * and for host adapters that support multiple busses
603	 * The last two should be set to 1 more than the actual max id
604	 * or lun (e.g. 8 for SCSI parallel systems).
605	 */
606	unsigned int max_channel;
607	unsigned int max_id;
608	u64 max_lun;
609
610	/*
611	 * This is a unique identifier that must be assigned so that we
612	 * have some way of identifying each detected host adapter properly
613	 * and uniquely.  For hosts that do not support more than one card
614	 * in the system at one time, this does not need to be set.  It is
615	 * initialized to 0 in scsi_host_alloc.
616	 */
617	unsigned int unique_id;
618
619	/*
620	 * The maximum length of SCSI commands that this host can accept.
621	 * Probably 12 for most host adapters, but could be 16 for others.
622	 * or 260 if the driver supports variable length cdbs.
623	 * For drivers that don't set this field, a value of 12 is
624	 * assumed.
625	 */
626	unsigned short max_cmd_len;
627
628	int this_id;
629
630	/*
631	 * Number of commands this host can handle at the same time.
632	 * This excludes reserved commands as specified by nr_reserved_cmds.
633	 */
634	int can_queue;
635	/*
636	 * Number of reserved commands to allocate, if any.
637	 */
638	unsigned int nr_reserved_cmds;
639
640	short cmd_per_lun;
641	short unsigned int sg_tablesize;
642	short unsigned int sg_prot_tablesize;
643	unsigned int max_sectors;
644	unsigned int opt_sectors;
645	unsigned int max_segment_size;
646	unsigned int dma_alignment;
647	unsigned long dma_boundary;
648	unsigned long virt_boundary_mask;
649	/*
650	 * In scsi-mq mode, the number of hardware queues supported by the LLD.
651	 *
652	 * Note: it is assumed that each hardware queue has a queue depth of
653	 * can_queue. In other words, the total queue depth per host
654	 * is nr_hw_queues * can_queue. However, for when host_tagset is set,
655	 * the total queue depth is can_queue.
656	 */
657	unsigned nr_hw_queues;
658	unsigned nr_maps;
659	unsigned active_mode:2;
660
661	/*
662	 * Host has requested that no further requests come through for the
663	 * time being.
664	 */
665	unsigned host_self_blocked:1;
666    
667	/*
668	 * Host uses correct SCSI ordering not PC ordering. The bit is
669	 * set for the minority of drivers whose authors actually read
670	 * the spec ;).
671	 */
672	unsigned reverse_ordering:1;
673
674	/* Task mgmt function in progress */
675	unsigned tmf_in_progress:1;
676
677	/* Asynchronous scan in progress */
678	unsigned async_scan:1;
679
680	/* Don't resume host in EH */
681	unsigned eh_noresume:1;
682
683	/* The controller does not support WRITE SAME */
684	unsigned no_write_same:1;
685
686	/* True if the host uses host-wide tagspace */
687	unsigned host_tagset:1;
688
689	/* The queuecommand callback may block. See also BLK_MQ_F_BLOCKING. */
690	unsigned queuecommand_may_block:1;
691
692	/* Host responded with short (<36 bytes) INQUIRY result */
693	unsigned short_inquiry:1;
694
695	/* The transport requires the LUN bits NOT to be stored in CDB[1] */
696	unsigned no_scsi2_lun_in_cdb:1;
697
698	/*
699	 * Optional work queue to be utilized by the transport
700	 */
701	struct workqueue_struct *work_q;
702
703	/*
704	 * Task management function work queue
705	 */
706	struct workqueue_struct *tmf_work_q;
707
708	/*
709	 * Value host_blocked counts down from
710	 */
711	unsigned int max_host_blocked;
712
713	/* Protection Information */
714	unsigned int prot_capabilities;
715	unsigned char prot_guard_type;
716
717	/* legacy crap */
718	unsigned long base;
719	unsigned long io_port;
720	unsigned char n_io_port;
721	unsigned char dma_channel;
722	unsigned int  irq;
723	
724
725	enum scsi_host_state shost_state;
726
727	/* ldm bits */
728	struct device		shost_gendev, shost_dev;
729
730	/*
731	 * A SCSI device structure used for sending internal commands to the
732	 * HBA. There is no corresponding logical unit inside the SCSI device.
733	 */
734	struct scsi_device *pseudo_sdev;
735
736	/*
737	 * Points to the transport data (if any) which is allocated
738	 * separately
739	 */
740	void *shost_data;
741
742	/*
743	 * Points to the physical bus device we'd use to do DMA
744	 * Needed just in case we have virtual hosts.
745	 */
746	struct device *dma_dev;
747
748	/* Delay for runtime autosuspend */
749	int rpm_autosuspend_delay;
750
751	/*
752	 * We should ensure that this is aligned, both for better performance
753	 * and also because some compilers (m68k) don't automatically force
754	 * alignment to a long boundary.
755	 */
756	unsigned long hostdata[]  /* Used for storage of host specific stuff */
757		__attribute__ ((aligned (sizeof(unsigned long))));
758};
759
760#define		class_to_shost(d)	\
761	container_of(d, struct Scsi_Host, shost_dev)
762
763#define shost_printk(prefix, shost, fmt, a...)	\
764	dev_printk(prefix, &(shost)->shost_gendev, fmt, ##a)
765
766static inline void *shost_priv(struct Scsi_Host *shost)
767{
768	return (void *)shost->hostdata;
769}
770
771int scsi_is_host_device(const struct device *);
772
773static inline struct Scsi_Host *dev_to_shost(struct device *dev)
774{
775	while (!scsi_is_host_device(dev)) {
776		if (!dev->parent)
777			return NULL;
778		dev = dev->parent;
779	}
780	return container_of(dev, struct Scsi_Host, shost_gendev);
781}
782
783static inline int scsi_host_in_recovery(struct Scsi_Host *shost)
784{
785	return shost->shost_state == SHOST_RECOVERY ||
786		shost->shost_state == SHOST_CANCEL_RECOVERY ||
787		shost->shost_state == SHOST_DEL_RECOVERY ||
788		shost->tmf_in_progress;
789}
790
791extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *);
792extern void scsi_flush_work(struct Scsi_Host *);
793
794extern struct Scsi_Host *scsi_host_alloc(const struct scsi_host_template *, int);
795extern int __must_check scsi_add_host_with_dma(struct Scsi_Host *,
796					       struct device *,
797					       struct device *);
798#if defined(CONFIG_SCSI_PROC_FS)
799struct proc_dir_entry *
800scsi_template_proc_dir(const struct scsi_host_template *sht);
801#else
802#define scsi_template_proc_dir(sht) NULL
803#endif
804extern void scsi_scan_host(struct Scsi_Host *);
805extern int scsi_resume_device(struct scsi_device *sdev);
806extern int scsi_rescan_device(struct scsi_device *sdev);
807extern void scsi_remove_host(struct Scsi_Host *);
808extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);
809extern int scsi_host_busy(struct Scsi_Host *shost);
810extern void scsi_host_put(struct Scsi_Host *t);
811extern struct Scsi_Host *scsi_host_lookup(unsigned int hostnum);
812extern const char *scsi_host_state_name(enum scsi_host_state);
813extern void scsi_host_complete_all_commands(struct Scsi_Host *shost,
814					    enum scsi_host_status status);
815
816static inline int __must_check scsi_add_host(struct Scsi_Host *host,
817					     struct device *dev)
818{
819	return scsi_add_host_with_dma(host, dev, dev);
820}
821
822static inline struct device *scsi_get_device(struct Scsi_Host *shost)
823{
824        return shost->shost_gendev.parent;
825}
826
827/**
828 * scsi_host_scan_allowed - Is scanning of this host allowed
829 * @shost:	Pointer to Scsi_Host.
830 **/
831static inline int scsi_host_scan_allowed(struct Scsi_Host *shost)
832{
833	return shost->shost_state == SHOST_RUNNING ||
834	       shost->shost_state == SHOST_RECOVERY;
835}
836
837extern void scsi_unblock_requests(struct Scsi_Host *);
838extern void scsi_block_requests(struct Scsi_Host *);
839extern int scsi_host_block(struct Scsi_Host *shost);
840extern int scsi_host_unblock(struct Scsi_Host *shost, int new_state);
841
842void scsi_host_busy_iter(struct Scsi_Host *,
843			 bool (*fn)(struct scsi_cmnd *, void *), void *priv);
844
845struct class_container;
846
847/*
848 * DIF defines the exchange of protection information between
849 * initiator and SBC block device.
850 *
851 * DIX defines the exchange of protection information between OS and
852 * initiator.
853 */
854enum scsi_host_prot_capabilities {
855	SHOST_DIF_TYPE1_PROTECTION = 1 << 0, /* T10 DIF Type 1 */
856	SHOST_DIF_TYPE2_PROTECTION = 1 << 1, /* T10 DIF Type 2 */
857	SHOST_DIF_TYPE3_PROTECTION = 1 << 2, /* T10 DIF Type 3 */
858
859	SHOST_DIX_TYPE0_PROTECTION = 1 << 3, /* DIX between OS and HBA only */
860	SHOST_DIX_TYPE1_PROTECTION = 1 << 4, /* DIX with DIF Type 1 */
861	SHOST_DIX_TYPE2_PROTECTION = 1 << 5, /* DIX with DIF Type 2 */
862	SHOST_DIX_TYPE3_PROTECTION = 1 << 6, /* DIX with DIF Type 3 */
863};
864
865/*
866 * SCSI hosts which support the Data Integrity Extensions must
867 * indicate their capabilities by setting the prot_capabilities using
868 * this call.
869 */
870static inline void scsi_host_set_prot(struct Scsi_Host *shost, unsigned int mask)
871{
872	shost->prot_capabilities = mask;
873}
874
875static inline unsigned int scsi_host_get_prot(struct Scsi_Host *shost)
876{
877	return shost->prot_capabilities;
878}
879
880static inline int scsi_host_prot_dma(struct Scsi_Host *shost)
881{
882	return shost->prot_capabilities >= SHOST_DIX_TYPE0_PROTECTION;
883}
884
885static inline unsigned int scsi_host_dif_capable(struct Scsi_Host *shost, unsigned int target_type)
886{
887	static unsigned char cap[] = { 0,
888				       SHOST_DIF_TYPE1_PROTECTION,
889				       SHOST_DIF_TYPE2_PROTECTION,
890				       SHOST_DIF_TYPE3_PROTECTION };
891
892	if (target_type >= ARRAY_SIZE(cap))
893		return 0;
894
895	return shost->prot_capabilities & cap[target_type] ? target_type : 0;
896}
897
898static inline unsigned int scsi_host_dix_capable(struct Scsi_Host *shost, unsigned int target_type)
899{
900#if defined(CONFIG_BLK_DEV_INTEGRITY)
901	static unsigned char cap[] = { SHOST_DIX_TYPE0_PROTECTION,
902				       SHOST_DIX_TYPE1_PROTECTION,
903				       SHOST_DIX_TYPE2_PROTECTION,
904				       SHOST_DIX_TYPE3_PROTECTION };
905
906	if (target_type >= ARRAY_SIZE(cap))
907		return 0;
908
909	return shost->prot_capabilities & cap[target_type];
910#endif
911	return 0;
912}
913
914/*
915 * All DIX-capable initiators must support the T10-mandated CRC
916 * checksum.  Controllers can optionally implement the IP checksum
917 * scheme which has much lower impact on system performance.  Note
918 * that the main rationale for the checksum is to match integrity
919 * metadata with data.  Detecting bit errors are a job for ECC memory
920 * and buses.
921 */
922
923enum scsi_host_guard_type {
924	SHOST_DIX_GUARD_CRC = 1 << 0,
925	SHOST_DIX_GUARD_IP  = 1 << 1,
926};
927
928static inline void scsi_host_set_guard(struct Scsi_Host *shost, unsigned char type)
929{
930	shost->prot_guard_type = type;
931}
932
933static inline unsigned char scsi_host_get_guard(struct Scsi_Host *shost)
934{
935	return shost->prot_guard_type;
936}
937
938extern int scsi_host_set_state(struct Scsi_Host *, enum scsi_host_state);
939
940#endif /* _SCSI_SCSI_HOST_H */