1 #ifndef _SCSI_SCSI_HOST_H
2 #define _SCSI_SCSI_HOST_H
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>
18 struct scsi_host_cmd_pool;
19 struct scsi_transport_template;
20 struct blk_queue_tags;
24 * The various choices mean:
25 * NONE: Self evident. Host adapter is not capable of scatter-gather.
26 * ALL: Means that the host adapter module can do scatter-gather,
27 * and that there is no limit to the size of the table to which
28 * we scatter/gather data.
29 * Anything else: Indicates the maximum number of chains that can be
30 * used in one scatter-gather request.
35 #define MODE_UNKNOWN 0x00
36 #define MODE_INITIATOR 0x01
37 #define MODE_TARGET 0x02
39 #define DISABLE_CLUSTERING 0
40 #define ENABLE_CLUSTERING 1
42 enum scsi_eh_timer_return {
49 struct scsi_host_template {
50 struct module *module;
54 * Used to initialize old-style drivers. For new-style drivers
55 * just perform all work in your module initialization function.
59 int (* detect)(struct scsi_host_template *);
62 * Used as unload callback for hosts with old-style drivers.
66 int (* release)(struct Scsi_Host *);
69 * The info function will return whatever useful information the
70 * developer sees fit. If not provided, then the name field will
75 const char *(* info)(struct Scsi_Host *);
82 int (* ioctl)(struct scsi_device *dev, int cmd, void __user *arg);
87 * Compat handler. Handle 32bit ABI.
88 * When unknown ioctl is passed return -ENOIOCTLCMD.
92 int (* compat_ioctl)(struct scsi_device *dev, int cmd, void __user *arg);
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.
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).
106 * Queuecommand may also reject the command, in which case it may
107 * not touch the command and must not call done() for it.
109 * There are two possible rejection returns:
111 * SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but
112 * allow commands to other devices serviced by this host.
114 * SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this
117 * For compatibility, any other non-zero return is treated the
118 * same as SCSI_MLQUEUE_HOST_BUSY.
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
127 int (* queuecommand)(struct scsi_cmnd *,
128 void (*done)(struct scsi_cmnd *));
131 * The transfer functions are used to queue a scsi command to
132 * the LLD. When the driver is finished processing the command
133 * the done callback is invoked.
135 * This is called to inform the LLD to transfer
136 * scsi_bufflen(cmd) bytes. scsi_sg_count(cmd) speciefies the
137 * number of scatterlist entried in the command and
138 * scsi_sglist(cmd) returns the scatterlist.
140 * return values: see queuecommand
142 * If the LLD accepts the cmd, it should set the result to an
143 * appropriate value when completed before calling the done function.
145 * STATUS: REQUIRED FOR TARGET DRIVERS
148 int (* transfer_response)(struct scsi_cmnd *,
149 void (*done)(struct scsi_cmnd *));
152 * This is an error handling strategy routine. You don't need to
153 * define one of these if you don't want to - there is a default
154 * routine that is present that should work in most cases. For those
155 * driver authors that have the inclination and ability to write their
156 * own strategy routine, this is where it is specified. Note - the
157 * strategy routine is *ALWAYS* run in the context of the kernel eh
158 * thread. Thus you are guaranteed to *NOT* be in an interrupt
159 * handler when you execute this, and you are also guaranteed to
160 * *NOT* have any other commands being queued while you are in the
161 * strategy routine. When you return from this function, operations
164 * See scsi_error.c scsi_unjam_host for additional comments about
165 * what this function should and should not be attempting to do.
167 * Status: REQUIRED (at least one of them)
169 int (* eh_abort_handler)(struct scsi_cmnd *);
170 int (* eh_device_reset_handler)(struct scsi_cmnd *);
171 int (* eh_bus_reset_handler)(struct scsi_cmnd *);
172 int (* eh_host_reset_handler)(struct scsi_cmnd *);
175 * Before the mid layer attempts to scan for a new device where none
176 * currently exists, it will call this entry in your driver. Should
177 * your driver need to allocate any structs or perform any other init
178 * items in order to send commands to a currently unused target/lun
179 * combo, then this is where you can perform those allocations. This
180 * is specifically so that drivers won't have to perform any kind of
181 * "is this a new device" checks in their queuecommand routine,
182 * thereby making the hot path a bit quicker.
184 * Return values: 0 on success, non-0 on failure
186 * Deallocation: If we didn't find any devices at this ID, you will
187 * get an immediate call to slave_destroy(). If we find something
188 * here then you will get a call to slave_configure(), then the
189 * device will be used for however long it is kept around, then when
190 * the device is removed from the system (or * possibly at reboot
191 * time), you will then get a call to slave_destroy(). This is
192 * assuming you implement slave_configure and slave_destroy.
193 * However, if you allocate memory and hang it off the device struct,
194 * then you must implement the slave_destroy() routine at a minimum
195 * in order to avoid leaking memory
196 * each time a device is tore down.
200 int (* slave_alloc)(struct scsi_device *);
203 * Once the device has responded to an INQUIRY and we know the
204 * device is online, we call into the low level driver with the
205 * struct scsi_device *. If the low level device driver implements
206 * this function, it *must* perform the task of setting the queue
207 * depth on the device. All other tasks are optional and depend
208 * on what the driver supports and various implementation details.
210 * Things currently recommended to be handled at this time include:
212 * 1. Setting the device queue depth. Proper setting of this is
213 * described in the comments for scsi_adjust_queue_depth.
214 * 2. Determining if the device supports the various synchronous
215 * negotiation protocols. The device struct will already have
216 * responded to INQUIRY and the results of the standard items
217 * will have been shoved into the various device flag bits, eg.
218 * device->sdtr will be true if the device supports SDTR messages.
219 * 3. Allocating command structs that the device will need.
220 * 4. Setting the default timeout on this device (if needed).
221 * 5. Anything else the low level driver might want to do on a device
222 * specific setup basis...
223 * 6. Return 0 on success, non-0 on error. The device will be marked
224 * as offline on error so that no access will occur. If you return
225 * non-0, your slave_destroy routine will never get called for this
226 * device, so don't leave any loose memory hanging around, clean
227 * up after yourself before returning non-0
231 int (* slave_configure)(struct scsi_device *);
234 * Immediately prior to deallocating the device and after all activity
235 * has ceased the mid layer calls this point so that the low level
236 * driver may completely detach itself from the scsi device and vice
237 * versa. The low level driver is responsible for freeing any memory
238 * it allocated in the slave_alloc or slave_configure calls.
242 void (* slave_destroy)(struct scsi_device *);
245 * Before the mid layer attempts to scan for a new device attached
246 * to a target where no target currently exists, it will call this
247 * entry in your driver. Should your driver need to allocate any
248 * structs or perform any other init items in order to send commands
249 * to a currently unused target, then this is where you can perform
252 * Return values: 0 on success, non-0 on failure
256 int (* target_alloc)(struct scsi_target *);
259 * Immediately prior to deallocating the target structure, and
260 * after all activity to attached scsi devices has ceased, the
261 * midlayer calls this point so that the driver may deallocate
262 * and terminate any references to the target.
266 void (* target_destroy)(struct scsi_target *);
269 * If a host has the ability to discover targets on its own instead
270 * of scanning the entire bus, it can fill in this function and
271 * call scsi_scan_host(). This function will be called periodically
272 * until it returns 1 with the scsi_host and the elapsed time of
273 * the scan in jiffies.
277 int (* scan_finished)(struct Scsi_Host *, unsigned long);
280 * If the host wants to be called before the scan starts, but
281 * after the midlayer has set up ready for the scan, it can fill
286 void (* scan_start)(struct Scsi_Host *);
289 * Fill in this function to allow the queue depth of this host
290 * to be changeable (on a per device basis). Returns either
291 * the current queue depth setting (may be different from what
292 * was passed in) or an error. An error should only be
293 * returned if the requested depth is legal but the driver was
294 * unable to set it. If the requested depth is illegal, the
295 * driver should set and return the closest legal queue depth.
299 int (* change_queue_depth)(struct scsi_device *, int);
302 * Fill in this function to allow the changing of tag types
303 * (this also allows the enabling/disabling of tag command
304 * queueing). An error should only be returned if something
305 * went wrong in the driver while trying to set the tag type.
306 * If the driver doesn't support the requested tag type, then
307 * it should set the closest type it does support without
308 * returning an error. Returns the actual tag type set.
312 int (* change_queue_type)(struct scsi_device *, int);
315 * This function determines the BIOS parameters for a given
316 * harddisk. These tend to be numbers that are made up by
317 * the host adapter. Parameters:
318 * size, device, list (heads, sectors, cylinders)
322 int (* bios_param)(struct scsi_device *, struct block_device *,
326 * Can be used to export driver statistics and other infos to the
327 * world outside the kernel ie. userspace and it also provides an
328 * interface to feed the driver with information.
332 int (*proc_info)(struct Scsi_Host *, char *, char **, off_t, int, int);
335 * This is an optional routine that allows the transport to become
336 * involved when a scsi io timer fires. The return value tells the
337 * timer routine how to finish the io timeout handling:
338 * EH_HANDLED: I fixed the error, please complete the command
339 * EH_RESET_TIMER: I need more time, reset the timer and
340 * begin counting again
341 * EH_NOT_HANDLED Begin normal error recovery
345 enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
348 * Name of proc directory
350 const char *proc_name;
353 * Used to store the procfs directory if a driver implements the
356 struct proc_dir_entry *proc_dir;
359 * This determines if we will use a non-interrupt driven
360 * or an interrupt driven scheme. It is set to the maximum number
361 * of simultaneous commands a given host adapter will accept.
366 * In many instances, especially where disconnect / reconnect are
367 * supported, our host also has an ID on the SCSI bus. If this is
368 * the case, then it must be reserved. Please set this_id to -1 if
369 * your setup is in single initiator mode, and the host lacks an
375 * This determines the degree to which the host adapter is capable
378 unsigned short sg_tablesize;
381 * Set this if the host adapter has limitations beside segment count.
383 unsigned short max_sectors;
386 * DMA scatter gather segment boundary limit. A segment crossing this
387 * boundary will be split in two.
389 unsigned long dma_boundary;
392 * This specifies "machine infinity" for host templates which don't
393 * limit the transfer size. Note this limit represents an absolute
394 * maximum, and may be over the transfer limits allowed for
395 * individual devices (e.g. 256 for SCSI-1).
397 #define SCSI_DEFAULT_MAX_SECTORS 1024
400 * True if this host adapter can make good use of linked commands.
401 * This will allow more than one command to be queued to a given
402 * unit on a given host. Set this to the maximum number of command
403 * blocks to be provided for each device. Set this to 1 for one
404 * command block per lun, 2 for two, etc. Do not set this to 0.
405 * You should make sure that the host adapter will do the right thing
406 * before you try setting this above 1.
411 * present contains counter indicating how many boards of this
412 * type were found when we did the scan.
414 unsigned char present;
417 * This specifies the mode that a LLD supports.
419 unsigned supported_mode:2;
422 * True if this host adapter uses unchecked DMA onto an ISA bus.
424 unsigned unchecked_isa_dma:1;
427 * True if this host adapter can make good use of clustering.
428 * I originally thought that if the tablesize was large that it
429 * was a waste of CPU cycles to prepare a cluster list, but
430 * it works out that the Buslogic is faster if you use a smaller
431 * number of segments (i.e. use clustering). I guess it is
434 unsigned use_clustering:1;
437 * True for emulated SCSI host adapters (e.g. ATAPI).
442 * True if the low-level driver performs its own reset-settle delays.
444 unsigned skip_settle_delay:1;
447 * True if we are using ordered write support.
449 unsigned ordered_tag:1;
452 * Countdown for host blocking with no commands outstanding.
454 unsigned int max_host_blocked;
457 * Default value for the blocking. If the queue is empty,
458 * host_blocked counts down in the request_fn until it restarts
459 * host operations as zero is reached.
461 * FIXME: This should probably be a value in the template
463 #define SCSI_DEFAULT_HOST_BLOCKED 7
466 * Pointer to the sysfs class properties for this host, NULL terminated.
468 struct class_device_attribute **shost_attrs;
471 * Pointer to the SCSI device properties for this host, NULL terminated.
473 struct device_attribute **sdev_attrs;
476 * List of hosts per template.
478 * This is only for use by scsi_module.c for legacy templates.
479 * For these access to it is synchronized implicitly by
480 * module_init/module_exit.
482 struct list_head legacy_hosts;
486 * shost state: If you alter this, you also need to alter scsi_sysfs.c
487 * (for the ascii descriptions) and the state model enforcer:
488 * scsi_host_set_state()
490 enum scsi_host_state {
496 SHOST_CANCEL_RECOVERY,
502 * __devices is protected by the host_lock, but you should
503 * usually use scsi_device_lookup / shost_for_each_device
504 * to access it and don't care about locking yourself.
505 * In the rare case of beeing in irq context you can use
506 * their __ prefixed variants with the lock held. NEVER
507 * access this list directly from a driver.
509 struct list_head __devices;
510 struct list_head __targets;
512 struct scsi_host_cmd_pool *cmd_pool;
513 spinlock_t free_list_lock;
514 struct list_head free_list; /* backup store of cmd structs */
515 struct list_head starved_list;
517 spinlock_t default_lock;
518 spinlock_t *host_lock;
520 struct mutex scan_mutex;/* serialize scanning activity */
522 struct list_head eh_cmd_q;
523 struct task_struct * ehandler; /* Error recovery thread. */
524 struct completion * eh_action; /* Wait for specific actions on the
526 wait_queue_head_t host_wait;
527 struct scsi_host_template *hostt;
528 struct scsi_transport_template *transportt;
531 * Area to keep a shared tag map (if needed, will be
534 struct blk_queue_tag *bqt;
537 * The following two fields are protected with host_lock;
538 * however, eh routines can safely access during eh processing
539 * without acquiring the lock.
541 unsigned int host_busy; /* commands actually active on low-level */
542 unsigned int host_failed; /* commands that failed. */
543 unsigned int host_eh_scheduled; /* EH scheduled without command */
545 unsigned short host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
546 int resetting; /* if set, it means that last_reset is a valid value */
547 unsigned long last_reset;
550 * These three parameters can be used to allow for wide scsi,
551 * and for host adapters that support multiple busses
552 * The first two should be set to 1 more than the actual max id
553 * or lun (i.e. 8 for normal systems).
556 unsigned int max_lun;
557 unsigned int max_channel;
560 * This is a unique identifier that must be assigned so that we
561 * have some way of identifying each detected host adapter properly
562 * and uniquely. For hosts that do not support more than one card
563 * in the system at one time, this does not need to be set. It is
564 * initialized to 0 in scsi_register.
566 unsigned int unique_id;
569 * The maximum length of SCSI commands that this host can accept.
570 * Probably 12 for most host adapters, but could be 16 for others.
571 * For drivers that don't set this field, a value of 12 is
572 * assumed. I am leaving this as a number rather than a bit
573 * because you never know what subsequent SCSI standards might do
574 * (i.e. could there be a 20 byte or a 24-byte command a few years
577 unsigned char max_cmd_len;
582 short unsigned int sg_tablesize;
583 short unsigned int max_sectors;
584 unsigned long dma_boundary;
586 * Used to assign serial numbers to the cmds.
587 * Protected by the host lock.
589 unsigned long cmd_serial_number;
591 unsigned active_mode:2;
592 unsigned unchecked_isa_dma:1;
593 unsigned use_clustering:1;
594 unsigned use_blk_tcq:1;
597 * Host has requested that no further requests come through for the
600 unsigned host_self_blocked:1;
603 * Host uses correct SCSI ordering not PC ordering. The bit is
604 * set for the minority of drivers whose authors actually read
607 unsigned reverse_ordering:1;
610 * Ordered write support
612 unsigned ordered_tag:1;
614 /* Task mgmt function in progress */
615 unsigned tmf_in_progress:1;
617 /* Asynchronous scan in progress */
618 unsigned async_scan:1;
621 * Optional work queue to be utilized by the transport
623 char work_q_name[KOBJ_NAME_LEN];
624 struct workqueue_struct *work_q;
627 * Host has rejected a command because it was busy.
629 unsigned int host_blocked;
632 * Value host_blocked counts down from
634 unsigned int max_host_blocked;
637 * q used for scsi_tgt msgs, async events or any other requests that
638 * need to be processed in userspace
640 struct request_queue *uspace_req_q;
644 unsigned long io_port;
645 unsigned char n_io_port;
646 unsigned char dma_channel;
650 enum scsi_host_state shost_state;
653 struct device shost_gendev;
654 struct class_device shost_classdev;
657 * List of hosts per template.
659 * This is only for use by scsi_module.c for legacy templates.
660 * For these access to it is synchronized implicitly by
661 * module_init/module_exit.
663 struct list_head sht_legacy_list;
666 * Points to the transport data (if any) which is allocated
672 * We should ensure that this is aligned, both for better performance
673 * and also because some compilers (m68k) don't automatically force
674 * alignment to a long boundary.
676 unsigned long hostdata[0] /* Used for storage of host specific stuff */
677 __attribute__ ((aligned (sizeof(unsigned long))));
680 #define class_to_shost(d) \
681 container_of(d, struct Scsi_Host, shost_classdev)
683 #define shost_printk(prefix, shost, fmt, a...) \
684 dev_printk(prefix, &(shost)->shost_gendev, fmt, ##a)
686 static inline void *shost_priv(struct Scsi_Host *shost)
688 return (void *)shost->hostdata;
691 int scsi_is_host_device(const struct device *);
693 static inline struct Scsi_Host *dev_to_shost(struct device *dev)
695 while (!scsi_is_host_device(dev)) {
700 return container_of(dev, struct Scsi_Host, shost_gendev);
703 static inline int scsi_host_in_recovery(struct Scsi_Host *shost)
705 return shost->shost_state == SHOST_RECOVERY ||
706 shost->shost_state == SHOST_CANCEL_RECOVERY ||
707 shost->shost_state == SHOST_DEL_RECOVERY ||
708 shost->tmf_in_progress;
711 extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *);
712 extern void scsi_flush_work(struct Scsi_Host *);
714 extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int);
715 extern int __must_check scsi_add_host(struct Scsi_Host *, struct device *);
716 extern void scsi_scan_host(struct Scsi_Host *);
717 extern void scsi_rescan_device(struct device *);
718 extern void scsi_remove_host(struct Scsi_Host *);
719 extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);
720 extern void scsi_host_put(struct Scsi_Host *t);
721 extern struct Scsi_Host *scsi_host_lookup(unsigned short);
722 extern const char *scsi_host_state_name(enum scsi_host_state);
724 extern u64 scsi_calculate_bounce_limit(struct Scsi_Host *);
726 static inline struct device *scsi_get_device(struct Scsi_Host *shost)
728 return shost->shost_gendev.parent;
732 * scsi_host_scan_allowed - Is scanning of this host allowed
733 * @shost: Pointer to Scsi_Host.
735 static inline int scsi_host_scan_allowed(struct Scsi_Host *shost)
737 return shost->shost_state == SHOST_RUNNING;
740 extern void scsi_unblock_requests(struct Scsi_Host *);
741 extern void scsi_block_requests(struct Scsi_Host *);
743 struct class_container;
745 extern struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
746 void (*) (struct request_queue *));
748 * These two functions are used to allocate and free a pseudo device
749 * which will connect to the host adapter itself rather than any
750 * physical device. You must deallocate when you are done with the
751 * thing. This physical pseudo-device isn't real and won't be available
752 * from any high-level drivers.
754 extern void scsi_free_host_dev(struct scsi_device *);
755 extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *);
757 /* legacy interfaces */
758 extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int);
759 extern void scsi_unregister(struct Scsi_Host *);
760 extern int scsi_host_set_state(struct Scsi_Host *, enum scsi_host_state);
762 #endif /* _SCSI_SCSI_HOST_H */