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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#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
9struct block_device;
10struct module;
11struct scsi_cmnd;
12struct scsi_device;
James Bottomleya283bd32005-05-24 12:06:38 -050013struct scsi_target;
Linus Torvalds1da177e2005-04-16 15:20:36 -070014struct Scsi_Host;
15struct scsi_host_cmd_pool;
16struct scsi_transport_template;
17
18
19/*
20 * The various choices mean:
21 * NONE: Self evident. Host adapter is not capable of scatter-gather.
22 * ALL: Means that the host adapter module can do scatter-gather,
23 * and that there is no limit to the size of the table to which
24 * we scatter/gather data.
25 * Anything else: Indicates the maximum number of chains that can be
26 * used in one scatter-gather request.
27 */
28#define SG_NONE 0
29#define SG_ALL 0xff
30
31
32#define DISABLE_CLUSTERING 0
33#define ENABLE_CLUSTERING 1
34
35enum scsi_eh_timer_return {
36 EH_NOT_HANDLED,
37 EH_HANDLED,
38 EH_RESET_TIMER,
39};
40
41
42struct scsi_host_template {
43 struct module *module;
44 const char *name;
45
46 /*
47 * Used to initialize old-style drivers. For new-style drivers
48 * just perform all work in your module initialization function.
49 *
50 * Status: OBSOLETE
51 */
52 int (* detect)(struct scsi_host_template *);
53
54 /*
55 * Used as unload callback for hosts with old-style drivers.
56 *
57 * Status: OBSOLETE
58 */
59 int (* release)(struct Scsi_Host *);
60
61 /*
62 * The info function will return whatever useful information the
63 * developer sees fit. If not provided, then the name field will
64 * be used instead.
65 *
66 * Status: OPTIONAL
67 */
68 const char *(* info)(struct Scsi_Host *);
69
70 /*
71 * Ioctl interface
72 *
73 * Status: OPTIONAL
74 */
75 int (* ioctl)(struct scsi_device *dev, int cmd, void __user *arg);
76
77
78#ifdef CONFIG_COMPAT
79 /*
80 * Compat handler. Handle 32bit ABI.
81 * When unknown ioctl is passed return -ENOIOCTLCMD.
82 *
83 * Status: OPTIONAL
84 */
85 int (* compat_ioctl)(struct scsi_device *dev, int cmd, void __user *arg);
86#endif
87
88 /*
89 * The queuecommand function is used to queue up a scsi
90 * command block to the LLDD. When the driver finished
91 * processing the command the done callback is invoked.
92 *
93 * If queuecommand returns 0, then the HBA has accepted the
94 * command. The done() function must be called on the command
95 * when the driver has finished with it. (you may call done on the
96 * command before queuecommand returns, but in this case you
97 * *must* return 0 from queuecommand).
98 *
99 * Queuecommand may also reject the command, in which case it may
100 * not touch the command and must not call done() for it.
101 *
102 * There are two possible rejection returns:
103 *
104 * SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but
105 * allow commands to other devices serviced by this host.
106 *
107 * SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this
108 * host temporarily.
109 *
110 * For compatibility, any other non-zero return is treated the
111 * same as SCSI_MLQUEUE_HOST_BUSY.
112 *
113 * NOTE: "temporarily" means either until the next command for#
114 * this device/host completes, or a period of time determined by
115 * I/O pressure in the system if there are no other outstanding
116 * commands.
117 *
118 * STATUS: REQUIRED
119 */
120 int (* queuecommand)(struct scsi_cmnd *,
121 void (*done)(struct scsi_cmnd *));
122
123 /*
124 * This is an error handling strategy routine. You don't need to
125 * define one of these if you don't want to - there is a default
126 * routine that is present that should work in most cases. For those
127 * driver authors that have the inclination and ability to write their
128 * own strategy routine, this is where it is specified. Note - the
129 * strategy routine is *ALWAYS* run in the context of the kernel eh
130 * thread. Thus you are guaranteed to *NOT* be in an interrupt
131 * handler when you execute this, and you are also guaranteed to
132 * *NOT* have any other commands being queued while you are in the
133 * strategy routine. When you return from this function, operations
134 * return to normal.
135 *
136 * See scsi_error.c scsi_unjam_host for additional comments about
137 * what this function should and should not be attempting to do.
138 *
139 * Status: REQUIRED (at least one of them)
140 */
141 int (* eh_strategy_handler)(struct Scsi_Host *);
142 int (* eh_abort_handler)(struct scsi_cmnd *);
143 int (* eh_device_reset_handler)(struct scsi_cmnd *);
144 int (* eh_bus_reset_handler)(struct scsi_cmnd *);
145 int (* eh_host_reset_handler)(struct scsi_cmnd *);
146
147 /*
148 * This is an optional routine to notify the host that the scsi
149 * timer just fired. The returns tell the timer routine what to
150 * do about this:
151 *
152 * EH_HANDLED: I fixed the error, please complete the command
153 * EH_RESET_TIMER: I need more time, reset the timer and
154 * begin counting again
155 * EH_NOT_HANDLED Begin normal error recovery
156 *
157 * Status: OPTIONAL
158 */
159 enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
160
161 /*
162 * Before the mid layer attempts to scan for a new device where none
163 * currently exists, it will call this entry in your driver. Should
164 * your driver need to allocate any structs or perform any other init
165 * items in order to send commands to a currently unused target/lun
166 * combo, then this is where you can perform those allocations. This
167 * is specifically so that drivers won't have to perform any kind of
168 * "is this a new device" checks in their queuecommand routine,
169 * thereby making the hot path a bit quicker.
170 *
171 * Return values: 0 on success, non-0 on failure
172 *
173 * Deallocation: If we didn't find any devices at this ID, you will
174 * get an immediate call to slave_destroy(). If we find something
175 * here then you will get a call to slave_configure(), then the
176 * device will be used for however long it is kept around, then when
177 * the device is removed from the system (or * possibly at reboot
178 * time), you will then get a call to slave_destroy(). This is
179 * assuming you implement slave_configure and slave_destroy.
180 * However, if you allocate memory and hang it off the device struct,
181 * then you must implement the slave_destroy() routine at a minimum
182 * in order to avoid leaking memory
183 * each time a device is tore down.
184 *
185 * Status: OPTIONAL
186 */
187 int (* slave_alloc)(struct scsi_device *);
188
189 /*
190 * Once the device has responded to an INQUIRY and we know the
191 * device is online, we call into the low level driver with the
192 * struct scsi_device *. If the low level device driver implements
193 * this function, it *must* perform the task of setting the queue
194 * depth on the device. All other tasks are optional and depend
195 * on what the driver supports and various implementation details.
196 *
197 * Things currently recommended to be handled at this time include:
198 *
199 * 1. Setting the device queue depth. Proper setting of this is
200 * described in the comments for scsi_adjust_queue_depth.
201 * 2. Determining if the device supports the various synchronous
202 * negotiation protocols. The device struct will already have
203 * responded to INQUIRY and the results of the standard items
204 * will have been shoved into the various device flag bits, eg.
205 * device->sdtr will be true if the device supports SDTR messages.
206 * 3. Allocating command structs that the device will need.
207 * 4. Setting the default timeout on this device (if needed).
208 * 5. Anything else the low level driver might want to do on a device
209 * specific setup basis...
210 * 6. Return 0 on success, non-0 on error. The device will be marked
211 * as offline on error so that no access will occur. If you return
212 * non-0, your slave_destroy routine will never get called for this
213 * device, so don't leave any loose memory hanging around, clean
214 * up after yourself before returning non-0
215 *
216 * Status: OPTIONAL
217 */
218 int (* slave_configure)(struct scsi_device *);
219
220 /*
221 * Immediately prior to deallocating the device and after all activity
222 * has ceased the mid layer calls this point so that the low level
223 * driver may completely detach itself from the scsi device and vice
224 * versa. The low level driver is responsible for freeing any memory
225 * it allocated in the slave_alloc or slave_configure calls.
226 *
227 * Status: OPTIONAL
228 */
229 void (* slave_destroy)(struct scsi_device *);
230
231 /*
James Bottomleya283bd32005-05-24 12:06:38 -0500232 * Before the mid layer attempts to scan for a new device attached
233 * to a target where no target currently exists, it will call this
234 * entry in your driver. Should your driver need to allocate any
235 * structs or perform any other init items in order to send commands
236 * to a currently unused target, then this is where you can perform
237 * those allocations.
238 *
239 * Return values: 0 on success, non-0 on failure
240 *
241 * Status: OPTIONAL
242 */
243 int (* target_alloc)(struct scsi_target *);
244
245 /*
246 * Immediately prior to deallocating the target structure, and
247 * after all activity to attached scsi devices has ceased, the
248 * midlayer calls this point so that the driver may deallocate
249 * and terminate any references to the target.
250 *
251 * Status: OPTIONAL
252 */
253 void (* target_destroy)(struct scsi_target *);
254
255 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 * fill in this function to allow the queue depth of this host
257 * to be changeable (on a per device basis). returns either
258 * the current queue depth setting (may be different from what
259 * was passed in) or an error. An error should only be
260 * returned if the requested depth is legal but the driver was
261 * unable to set it. If the requested depth is illegal, the
262 * driver should set and return the closest legal queue depth.
263 *
264 */
265 int (* change_queue_depth)(struct scsi_device *, int);
266
267 /*
268 * fill in this function to allow the changing of tag types
269 * (this also allows the enabling/disabling of tag command
270 * queueing). An error should only be returned if something
271 * went wrong in the driver while trying to set the tag type.
272 * If the driver doesn't support the requested tag type, then
273 * it should set the closest type it does support without
274 * returning an error. Returns the actual tag type set.
275 */
276 int (* change_queue_type)(struct scsi_device *, int);
277
278 /*
279 * This function determines the bios parameters for a given
280 * harddisk. These tend to be numbers that are made up by
281 * the host adapter. Parameters:
282 * size, device, list (heads, sectors, cylinders)
283 *
284 * Status: OPTIONAL */
285 int (* bios_param)(struct scsi_device *, struct block_device *,
286 sector_t, int []);
287
288 /*
289 * Can be used to export driver statistics and other infos to the
290 * world outside the kernel ie. userspace and it also provides an
291 * interface to feed the driver with information.
292 *
293 * Status: OBSOLETE
294 */
295 int (*proc_info)(struct Scsi_Host *, char *, char **, off_t, int, int);
296
297 /*
298 * Name of proc directory
299 */
300 char *proc_name;
301
302 /*
303 * Used to store the procfs directory if a driver implements the
304 * proc_info method.
305 */
306 struct proc_dir_entry *proc_dir;
307
308 /*
309 * This determines if we will use a non-interrupt driven
310 * or an interrupt driven scheme, It is set to the maximum number
311 * of simultaneous commands a given host adapter will accept.
312 */
313 int can_queue;
314
315 /*
316 * In many instances, especially where disconnect / reconnect are
317 * supported, our host also has an ID on the SCSI bus. If this is
318 * the case, then it must be reserved. Please set this_id to -1 if
319 * your setup is in single initiator mode, and the host lacks an
320 * ID.
321 */
322 int this_id;
323
324 /*
325 * This determines the degree to which the host adapter is capable
326 * of scatter-gather.
327 */
328 unsigned short sg_tablesize;
329
330 /*
331 * If the host adapter has limitations beside segment count
332 */
333 unsigned short max_sectors;
334
335 /*
336 * dma scatter gather segment boundary limit. a segment crossing this
337 * boundary will be split in two.
338 */
339 unsigned long dma_boundary;
340
341 /*
342 * This specifies "machine infinity" for host templates which don't
343 * limit the transfer size. Note this limit represents an absolute
344 * maximum, and may be over the transfer limits allowed for
345 * individual devices (e.g. 256 for SCSI-1)
346 */
347#define SCSI_DEFAULT_MAX_SECTORS 1024
348
349 /*
350 * True if this host adapter can make good use of linked commands.
351 * This will allow more than one command to be queued to a given
352 * unit on a given host. Set this to the maximum number of command
353 * blocks to be provided for each device. Set this to 1 for one
354 * command block per lun, 2 for two, etc. Do not set this to 0.
355 * You should make sure that the host adapter will do the right thing
356 * before you try setting this above 1.
357 */
358 short cmd_per_lun;
359
360 /*
361 * present contains counter indicating how many boards of this
362 * type were found when we did the scan.
363 */
364 unsigned char present;
365
366 /*
367 * true if this host adapter uses unchecked DMA onto an ISA bus.
368 */
369 unsigned unchecked_isa_dma:1;
370
371 /*
372 * true if this host adapter can make good use of clustering.
373 * I originally thought that if the tablesize was large that it
374 * was a waste of CPU cycles to prepare a cluster list, but
375 * it works out that the Buslogic is faster if you use a smaller
376 * number of segments (i.e. use clustering). I guess it is
377 * inefficient.
378 */
379 unsigned use_clustering:1;
380
381 /*
382 * True for emulated SCSI host adapters (e.g. ATAPI)
383 */
384 unsigned emulated:1;
385
386 /*
387 * True if the low-level driver performs its own reset-settle delays.
388 */
389 unsigned skip_settle_delay:1;
390
391 /*
392 * ordered write support
393 */
394 unsigned ordered_flush:1;
395 unsigned ordered_tag:1;
396
397 /*
398 * Countdown for host blocking with no commands outstanding
399 */
400 unsigned int max_host_blocked;
401
402 /*
403 * Default value for the blocking. If the queue is empty,
404 * host_blocked counts down in the request_fn until it restarts
405 * host operations as zero is reached.
406 *
407 * FIXME: This should probably be a value in the template
408 */
409#define SCSI_DEFAULT_HOST_BLOCKED 7
410
411 /*
412 * Pointer to the sysfs class properties for this host, NULL terminated.
413 */
414 struct class_device_attribute **shost_attrs;
415
416 /*
417 * Pointer to the SCSI device properties for this host, NULL terminated.
418 */
419 struct device_attribute **sdev_attrs;
420
421 /*
422 * List of hosts per template.
423 *
424 * This is only for use by scsi_module.c for legacy templates.
425 * For these access to it is synchronized implicitly by
426 * module_init/module_exit.
427 */
428 struct list_head legacy_hosts;
429};
430
431/*
432 * shost states
433 */
434enum {
435 SHOST_ADD,
436 SHOST_DEL,
437 SHOST_CANCEL,
438 SHOST_RECOVERY,
439};
440
441struct Scsi_Host {
442 /*
443 * __devices is protected by the host_lock, but you should
444 * usually use scsi_device_lookup / shost_for_each_device
445 * to access it and don't care about locking yourself.
446 * In the rare case of beeing in irq context you can use
447 * their __ prefixed variants with the lock held. NEVER
448 * access this list directly from a driver.
449 */
450 struct list_head __devices;
451 struct list_head __targets;
452
453 struct scsi_host_cmd_pool *cmd_pool;
454 spinlock_t free_list_lock;
455 struct list_head free_list; /* backup store of cmd structs */
456 struct list_head starved_list;
457
458 spinlock_t default_lock;
459 spinlock_t *host_lock;
460
461 struct semaphore scan_mutex;/* serialize scanning activity */
462
463 struct list_head eh_cmd_q;
464 struct task_struct * ehandler; /* Error recovery thread. */
465 struct semaphore * eh_wait; /* The error recovery thread waits
466 on this. */
467 struct completion * eh_notify; /* wait for eh to begin or end */
468 struct semaphore * eh_action; /* Wait for specific actions on the
469 host. */
470 unsigned int eh_active:1; /* Indicates the eh thread is awake and active if
471 this is true. */
472 unsigned int eh_kill:1; /* set when killing the eh thread */
473 wait_queue_head_t host_wait;
474 struct scsi_host_template *hostt;
475 struct scsi_transport_template *transportt;
06f81ea2005-04-17 14:57:29 -0500476
477 /*
478 * The following two fields are protected with host_lock;
479 * however, eh routines can safely access during eh processing
480 * without acquiring the lock.
481 */
482 unsigned int host_busy; /* commands actually active on low-level */
483 unsigned int host_failed; /* commands that failed. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484
485 unsigned short host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
486 int resetting; /* if set, it means that last_reset is a valid value */
487 unsigned long last_reset;
488
489 /*
490 * These three parameters can be used to allow for wide scsi,
491 * and for host adapters that support multiple busses
492 * The first two should be set to 1 more than the actual max id
493 * or lun (i.e. 8 for normal systems).
494 */
495 unsigned int max_id;
496 unsigned int max_lun;
497 unsigned int max_channel;
498
499 /*
500 * This is a unique identifier that must be assigned so that we
501 * have some way of identifying each detected host adapter properly
502 * and uniquely. For hosts that do not support more than one card
503 * in the system at one time, this does not need to be set. It is
504 * initialized to 0 in scsi_register.
505 */
506 unsigned int unique_id;
507
508 /*
509 * The maximum length of SCSI commands that this host can accept.
510 * Probably 12 for most host adapters, but could be 16 for others.
511 * For drivers that don't set this field, a value of 12 is
512 * assumed. I am leaving this as a number rather than a bit
513 * because you never know what subsequent SCSI standards might do
514 * (i.e. could there be a 20 byte or a 24-byte command a few years
515 * down the road?).
516 */
517 unsigned char max_cmd_len;
518
519 int this_id;
520 int can_queue;
521 short cmd_per_lun;
522 short unsigned int sg_tablesize;
523 short unsigned int max_sectors;
524 unsigned long dma_boundary;
525 /*
526 * Used to assign serial numbers to the cmds.
527 * Protected by the host lock.
528 */
529 unsigned long cmd_serial_number, cmd_pid;
530
531 unsigned unchecked_isa_dma:1;
532 unsigned use_clustering:1;
533 unsigned use_blk_tcq:1;
534
535 /*
536 * Host has requested that no further requests come through for the
537 * time being.
538 */
539 unsigned host_self_blocked:1;
540
541 /*
542 * Host uses correct SCSI ordering not PC ordering. The bit is
543 * set for the minority of drivers whose authors actually read
544 * the spec ;)
545 */
546 unsigned reverse_ordering:1;
547
548 /*
549 * ordered write support
550 */
551 unsigned ordered_flush:1;
552 unsigned ordered_tag:1;
553
554 /*
555 * Optional work queue to be utilized by the transport
556 */
557 char work_q_name[KOBJ_NAME_LEN];
558 struct workqueue_struct *work_q;
559
560 /*
561 * Host has rejected a command because it was busy.
562 */
563 unsigned int host_blocked;
564
565 /*
566 * Value host_blocked counts down from
567 */
568 unsigned int max_host_blocked;
569
570 /* legacy crap */
571 unsigned long base;
572 unsigned long io_port;
573 unsigned char n_io_port;
574 unsigned char dma_channel;
575 unsigned int irq;
576
577
578 unsigned long shost_state;
579
580 /* ldm bits */
581 struct device shost_gendev;
582 struct class_device shost_classdev;
583
584 /*
585 * List of hosts per template.
586 *
587 * This is only for use by scsi_module.c for legacy templates.
588 * For these access to it is synchronized implicitly by
589 * module_init/module_exit.
590 */
591 struct list_head sht_legacy_list;
592
593 /*
594 * Points to the transport data (if any) which is allocated
595 * separately
596 */
597 void *shost_data;
598
599 /*
600 * We should ensure that this is aligned, both for better performance
601 * and also because some compilers (m68k) don't automatically force
602 * alignment to a long boundary.
603 */
604 unsigned long hostdata[0] /* Used for storage of host specific stuff */
605 __attribute__ ((aligned (sizeof(unsigned long))));
606};
607
608#define class_to_shost(d) \
609 container_of(d, struct Scsi_Host, shost_classdev)
610
611int scsi_is_host_device(const struct device *);
612
613static inline struct Scsi_Host *dev_to_shost(struct device *dev)
614{
615 while (!scsi_is_host_device(dev)) {
616 if (!dev->parent)
617 return NULL;
618 dev = dev->parent;
619 }
620 return container_of(dev, struct Scsi_Host, shost_gendev);
621}
622
623extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *);
624extern void scsi_flush_work(struct Scsi_Host *);
625
626extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int);
627extern int __must_check scsi_add_host(struct Scsi_Host *, struct device *);
628extern void scsi_scan_host(struct Scsi_Host *);
629extern void scsi_scan_single_target(struct Scsi_Host *, unsigned int,
630 unsigned int);
631extern void scsi_rescan_device(struct device *);
632extern void scsi_remove_host(struct Scsi_Host *);
633extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);
634extern void scsi_host_put(struct Scsi_Host *t);
635extern struct Scsi_Host *scsi_host_lookup(unsigned short);
636
637extern u64 scsi_calculate_bounce_limit(struct Scsi_Host *);
638
639static inline void scsi_assign_lock(struct Scsi_Host *shost, spinlock_t *lock)
640{
641 shost->host_lock = lock;
642}
643
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644static inline struct device *scsi_get_device(struct Scsi_Host *shost)
645{
646 return shost->shost_gendev.parent;
647}
648
649extern void scsi_unblock_requests(struct Scsi_Host *);
650extern void scsi_block_requests(struct Scsi_Host *);
651
652struct class_container;
653/*
654 * These two functions are used to allocate and free a pseudo device
655 * which will connect to the host adapter itself rather than any
656 * physical device. You must deallocate when you are done with the
657 * thing. This physical pseudo-device isn't real and won't be available
658 * from any high-level drivers.
659 */
660extern void scsi_free_host_dev(struct scsi_device *);
661extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *);
662
663/* legacy interfaces */
664extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int);
665extern void scsi_unregister(struct Scsi_Host *);
666
667#endif /* _SCSI_SCSI_HOST_H */