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>
13 struct scsi_host_cmd_pool;
14 struct scsi_transport_template;
18 * The various choices mean:
19 * NONE: Self evident. Host adapter is not capable of scatter-gather.
20 * ALL: Means that the host adapter module can do scatter-gather,
21 * and that there is no limit to the size of the table to which
22 * we scatter/gather data.
23 * Anything else: Indicates the maximum number of chains that can be
24 * used in one scatter-gather request.
30 #define DISABLE_CLUSTERING 0
31 #define ENABLE_CLUSTERING 1
33 enum scsi_eh_timer_return {
40 struct scsi_host_template {
41 struct module *module;
45 * Used to initialize old-style drivers. For new-style drivers
46 * just perform all work in your module initialization function.
50 int (* detect)(struct scsi_host_template *);
53 * Used as unload callback for hosts with old-style drivers.
57 int (* release)(struct Scsi_Host *);
60 * The info function will return whatever useful information the
61 * developer sees fit. If not provided, then the name field will
66 const char *(* info)(struct Scsi_Host *);
73 int (* ioctl)(struct scsi_device *dev, int cmd, void __user *arg);
78 * Compat handler. Handle 32bit ABI.
79 * When unknown ioctl is passed return -ENOIOCTLCMD.
83 int (* compat_ioctl)(struct scsi_device *dev, int cmd, void __user *arg);
87 * The queuecommand function is used to queue up a scsi
88 * command block to the LLDD. When the driver finished
89 * processing the command the done callback is invoked.
91 * If queuecommand returns 0, then the HBA has accepted the
92 * command. The done() function must be called on the command
93 * when the driver has finished with it. (you may call done on the
94 * command before queuecommand returns, but in this case you
95 * *must* return 0 from queuecommand).
97 * Queuecommand may also reject the command, in which case it may
98 * not touch the command and must not call done() for it.
100 * There are two possible rejection returns:
102 * SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but
103 * allow commands to other devices serviced by this host.
105 * SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this
108 * For compatibility, any other non-zero return is treated the
109 * same as SCSI_MLQUEUE_HOST_BUSY.
111 * NOTE: "temporarily" means either until the next command for#
112 * this device/host completes, or a period of time determined by
113 * I/O pressure in the system if there are no other outstanding
118 int (* queuecommand)(struct scsi_cmnd *,
119 void (*done)(struct scsi_cmnd *));
122 * This is an error handling strategy routine. You don't need to
123 * define one of these if you don't want to - there is a default
124 * routine that is present that should work in most cases. For those
125 * driver authors that have the inclination and ability to write their
126 * own strategy routine, this is where it is specified. Note - the
127 * strategy routine is *ALWAYS* run in the context of the kernel eh
128 * thread. Thus you are guaranteed to *NOT* be in an interrupt
129 * handler when you execute this, and you are also guaranteed to
130 * *NOT* have any other commands being queued while you are in the
131 * strategy routine. When you return from this function, operations
134 * See scsi_error.c scsi_unjam_host for additional comments about
135 * what this function should and should not be attempting to do.
137 * Status: REQUIRED (at least one of them)
139 int (* eh_strategy_handler)(struct Scsi_Host *);
140 int (* eh_abort_handler)(struct scsi_cmnd *);
141 int (* eh_device_reset_handler)(struct scsi_cmnd *);
142 int (* eh_bus_reset_handler)(struct scsi_cmnd *);
143 int (* eh_host_reset_handler)(struct scsi_cmnd *);
146 * This is an optional routine to notify the host that the scsi
147 * timer just fired. The returns tell the timer routine what to
150 * EH_HANDLED: I fixed the error, please complete the command
151 * EH_RESET_TIMER: I need more time, reset the timer and
152 * begin counting again
153 * EH_NOT_HANDLED Begin normal error recovery
157 enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
160 * Before the mid layer attempts to scan for a new device where none
161 * currently exists, it will call this entry in your driver. Should
162 * your driver need to allocate any structs or perform any other init
163 * items in order to send commands to a currently unused target/lun
164 * combo, then this is where you can perform those allocations. This
165 * is specifically so that drivers won't have to perform any kind of
166 * "is this a new device" checks in their queuecommand routine,
167 * thereby making the hot path a bit quicker.
169 * Return values: 0 on success, non-0 on failure
171 * Deallocation: If we didn't find any devices at this ID, you will
172 * get an immediate call to slave_destroy(). If we find something
173 * here then you will get a call to slave_configure(), then the
174 * device will be used for however long it is kept around, then when
175 * the device is removed from the system (or * possibly at reboot
176 * time), you will then get a call to slave_destroy(). This is
177 * assuming you implement slave_configure and slave_destroy.
178 * However, if you allocate memory and hang it off the device struct,
179 * then you must implement the slave_destroy() routine at a minimum
180 * in order to avoid leaking memory
181 * each time a device is tore down.
185 int (* slave_alloc)(struct scsi_device *);
188 * Once the device has responded to an INQUIRY and we know the
189 * device is online, we call into the low level driver with the
190 * struct scsi_device *. If the low level device driver implements
191 * this function, it *must* perform the task of setting the queue
192 * depth on the device. All other tasks are optional and depend
193 * on what the driver supports and various implementation details.
195 * Things currently recommended to be handled at this time include:
197 * 1. Setting the device queue depth. Proper setting of this is
198 * described in the comments for scsi_adjust_queue_depth.
199 * 2. Determining if the device supports the various synchronous
200 * negotiation protocols. The device struct will already have
201 * responded to INQUIRY and the results of the standard items
202 * will have been shoved into the various device flag bits, eg.
203 * device->sdtr will be true if the device supports SDTR messages.
204 * 3. Allocating command structs that the device will need.
205 * 4. Setting the default timeout on this device (if needed).
206 * 5. Anything else the low level driver might want to do on a device
207 * specific setup basis...
208 * 6. Return 0 on success, non-0 on error. The device will be marked
209 * as offline on error so that no access will occur. If you return
210 * non-0, your slave_destroy routine will never get called for this
211 * device, so don't leave any loose memory hanging around, clean
212 * up after yourself before returning non-0
216 int (* slave_configure)(struct scsi_device *);
219 * Immediately prior to deallocating the device and after all activity
220 * has ceased the mid layer calls this point so that the low level
221 * driver may completely detach itself from the scsi device and vice
222 * versa. The low level driver is responsible for freeing any memory
223 * it allocated in the slave_alloc or slave_configure calls.
227 void (* slave_destroy)(struct scsi_device *);
230 * fill in this function to allow the queue depth of this host
231 * to be changeable (on a per device basis). returns either
232 * the current queue depth setting (may be different from what
233 * was passed in) or an error. An error should only be
234 * returned if the requested depth is legal but the driver was
235 * unable to set it. If the requested depth is illegal, the
236 * driver should set and return the closest legal queue depth.
239 int (* change_queue_depth)(struct scsi_device *, int);
242 * fill in this function to allow the changing of tag types
243 * (this also allows the enabling/disabling of tag command
244 * queueing). An error should only be returned if something
245 * went wrong in the driver while trying to set the tag type.
246 * If the driver doesn't support the requested tag type, then
247 * it should set the closest type it does support without
248 * returning an error. Returns the actual tag type set.
250 int (* change_queue_type)(struct scsi_device *, int);
253 * This function determines the bios parameters for a given
254 * harddisk. These tend to be numbers that are made up by
255 * the host adapter. Parameters:
256 * size, device, list (heads, sectors, cylinders)
258 * Status: OPTIONAL */
259 int (* bios_param)(struct scsi_device *, struct block_device *,
263 * Can be used to export driver statistics and other infos to the
264 * world outside the kernel ie. userspace and it also provides an
265 * interface to feed the driver with information.
269 int (*proc_info)(struct Scsi_Host *, char *, char **, off_t, int, int);
272 * Name of proc directory
277 * Used to store the procfs directory if a driver implements the
280 struct proc_dir_entry *proc_dir;
283 * This determines if we will use a non-interrupt driven
284 * or an interrupt driven scheme, It is set to the maximum number
285 * of simultaneous commands a given host adapter will accept.
290 * In many instances, especially where disconnect / reconnect are
291 * supported, our host also has an ID on the SCSI bus. If this is
292 * the case, then it must be reserved. Please set this_id to -1 if
293 * your setup is in single initiator mode, and the host lacks an
299 * This determines the degree to which the host adapter is capable
302 unsigned short sg_tablesize;
305 * If the host adapter has limitations beside segment count
307 unsigned short max_sectors;
310 * dma scatter gather segment boundary limit. a segment crossing this
311 * boundary will be split in two.
313 unsigned long dma_boundary;
316 * This specifies "machine infinity" for host templates which don't
317 * limit the transfer size. Note this limit represents an absolute
318 * maximum, and may be over the transfer limits allowed for
319 * individual devices (e.g. 256 for SCSI-1)
321 #define SCSI_DEFAULT_MAX_SECTORS 1024
324 * True if this host adapter can make good use of linked commands.
325 * This will allow more than one command to be queued to a given
326 * unit on a given host. Set this to the maximum number of command
327 * blocks to be provided for each device. Set this to 1 for one
328 * command block per lun, 2 for two, etc. Do not set this to 0.
329 * You should make sure that the host adapter will do the right thing
330 * before you try setting this above 1.
335 * present contains counter indicating how many boards of this
336 * type were found when we did the scan.
338 unsigned char present;
341 * true if this host adapter uses unchecked DMA onto an ISA bus.
343 unsigned unchecked_isa_dma:1;
346 * true if this host adapter can make good use of clustering.
347 * I originally thought that if the tablesize was large that it
348 * was a waste of CPU cycles to prepare a cluster list, but
349 * it works out that the Buslogic is faster if you use a smaller
350 * number of segments (i.e. use clustering). I guess it is
353 unsigned use_clustering:1;
356 * True for emulated SCSI host adapters (e.g. ATAPI)
361 * True if the low-level driver performs its own reset-settle delays.
363 unsigned skip_settle_delay:1;
366 * Countdown for host blocking with no commands outstanding
368 unsigned int max_host_blocked;
371 * Default value for the blocking. If the queue is empty,
372 * host_blocked counts down in the request_fn until it restarts
373 * host operations as zero is reached.
375 * FIXME: This should probably be a value in the template
377 #define SCSI_DEFAULT_HOST_BLOCKED 7
380 * Pointer to the sysfs class properties for this host, NULL terminated.
382 struct class_device_attribute **shost_attrs;
385 * Pointer to the SCSI device properties for this host, NULL terminated.
387 struct device_attribute **sdev_attrs;
390 * List of hosts per template.
392 * This is only for use by scsi_module.c for legacy templates.
393 * For these access to it is synchronized implicitly by
394 * module_init/module_exit.
396 struct list_head legacy_hosts;
411 * __devices is protected by the host_lock, but you should
412 * usually use scsi_device_lookup / shost_for_each_device
413 * to access it and don't care about locking yourself.
414 * In the rare case of beeing in irq context you can use
415 * their __ prefixed variants with the lock held. NEVER
416 * access this list directly from a driver.
418 struct list_head __devices;
420 struct scsi_host_cmd_pool *cmd_pool;
421 spinlock_t free_list_lock;
422 struct list_head free_list; /* backup store of cmd structs */
423 struct list_head starved_list;
425 spinlock_t default_lock;
426 spinlock_t *host_lock;
428 struct semaphore scan_mutex;/* serialize scanning activity */
430 struct list_head eh_cmd_q;
431 struct task_struct * ehandler; /* Error recovery thread. */
432 struct semaphore * eh_wait; /* The error recovery thread waits
434 struct completion * eh_notify; /* wait for eh to begin or end */
435 struct semaphore * eh_action; /* Wait for specific actions on the
437 unsigned int eh_active:1; /* Indicates the eh thread is awake and active if
439 unsigned int eh_kill:1; /* set when killing the eh thread */
440 wait_queue_head_t host_wait;
441 struct scsi_host_template *hostt;
442 struct scsi_transport_template *transportt;
443 volatile unsigned short host_busy; /* commands actually active on low-level */
444 volatile unsigned short host_failed; /* commands that failed. */
446 unsigned short host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
447 int resetting; /* if set, it means that last_reset is a valid value */
448 unsigned long last_reset;
451 * These three parameters can be used to allow for wide scsi,
452 * and for host adapters that support multiple busses
453 * The first two should be set to 1 more than the actual max id
454 * or lun (i.e. 8 for normal systems).
457 unsigned int max_lun;
458 unsigned int max_channel;
461 * This is a unique identifier that must be assigned so that we
462 * have some way of identifying each detected host adapter properly
463 * and uniquely. For hosts that do not support more than one card
464 * in the system at one time, this does not need to be set. It is
465 * initialized to 0 in scsi_register.
467 unsigned int unique_id;
470 * The maximum length of SCSI commands that this host can accept.
471 * Probably 12 for most host adapters, but could be 16 for others.
472 * For drivers that don't set this field, a value of 12 is
473 * assumed. I am leaving this as a number rather than a bit
474 * because you never know what subsequent SCSI standards might do
475 * (i.e. could there be a 20 byte or a 24-byte command a few years
478 unsigned char max_cmd_len;
483 short unsigned int sg_tablesize;
484 short unsigned int max_sectors;
485 unsigned long dma_boundary;
487 unsigned unchecked_isa_dma:1;
488 unsigned use_clustering:1;
489 unsigned use_blk_tcq:1;
492 * Host has requested that no further requests come through for the
495 unsigned host_self_blocked:1;
498 * Host uses correct SCSI ordering not PC ordering. The bit is
499 * set for the minority of drivers whose authors actually read
502 unsigned reverse_ordering:1;
505 * Host has rejected a command because it was busy.
507 unsigned int host_blocked;
510 * Value host_blocked counts down from
512 unsigned int max_host_blocked;
516 unsigned long io_port;
517 unsigned char n_io_port;
518 unsigned char dma_channel;
522 unsigned long shost_state;
525 struct device shost_gendev;
526 struct class_device shost_classdev;
529 * List of hosts per template.
531 * This is only for use by scsi_module.c for legacy templates.
532 * For these access to it is synchronized implicitly by
533 * module_init/module_exit.
535 struct list_head sht_legacy_list;
538 * Points to the transport data (if any) which is allocated
544 * We should ensure that this is aligned, both for better performance
545 * and also because some compilers (m68k) don't automatically force
546 * alignment to a long boundary.
548 unsigned long hostdata[0] /* Used for storage of host specific stuff */
549 __attribute__ ((aligned (sizeof(unsigned long))));
551 #define dev_to_shost(d) \
552 container_of(d, struct Scsi_Host, shost_gendev)
553 #define class_to_shost(d) \
554 container_of(d, struct Scsi_Host, shost_classdev)
557 extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int);
558 extern int __must_check scsi_add_host(struct Scsi_Host *, struct device *);
559 extern void scsi_scan_host(struct Scsi_Host *);
560 extern void scsi_scan_single_target(struct Scsi_Host *, unsigned int,
562 extern void scsi_rescan_device(struct device *);
563 extern void scsi_remove_host(struct Scsi_Host *);
564 extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);
565 extern void scsi_host_put(struct Scsi_Host *t);
566 extern struct Scsi_Host *scsi_host_lookup(unsigned short);
568 extern u64 scsi_calculate_bounce_limit(struct Scsi_Host *);
570 static inline void scsi_assign_lock(struct Scsi_Host *shost, spinlock_t *lock)
572 shost->host_lock = lock;
575 static inline void scsi_set_device(struct Scsi_Host *shost,
578 shost->shost_gendev.parent = dev;
581 static inline struct device *scsi_get_device(struct Scsi_Host *shost)
583 return shost->shost_gendev.parent;
586 extern void scsi_unblock_requests(struct Scsi_Host *);
587 extern void scsi_block_requests(struct Scsi_Host *);
589 struct class_container;
591 * These two functions are used to allocate and free a pseudo device
592 * which will connect to the host adapter itself rather than any
593 * physical device. You must deallocate when you are done with the
594 * thing. This physical pseudo-device isn't real and won't be available
595 * from any high-level drivers.
597 extern void scsi_free_host_dev(struct scsi_device *);
598 extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *);
599 int scsi_is_host_device(const struct device *);
602 /* legacy interfaces */
603 extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int);
604 extern void scsi_unregister(struct Scsi_Host *);
606 #endif /* _SCSI_SCSI_HOST_H */