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);
76 * The queuecommand function is used to queue up a scsi
77 * command block to the LLDD. When the driver finished
78 * processing the command the done callback is invoked.
80 * If queuecommand returns 0, then the HBA has accepted the
81 * command. The done() function must be called on the command
82 * when the driver has finished with it. (you may call done on the
83 * command before queuecommand returns, but in this case you
84 * *must* return 0 from queuecommand).
86 * Queuecommand may also reject the command, in which case it may
87 * not touch the command and must not call done() for it.
89 * There are two possible rejection returns:
91 * SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but
92 * allow commands to other devices serviced by this host.
94 * SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this
97 * For compatibility, any other non-zero return is treated the
98 * same as SCSI_MLQUEUE_HOST_BUSY.
100 * NOTE: "temporarily" means either until the next command for#
101 * this device/host completes, or a period of time determined by
102 * I/O pressure in the system if there are no other outstanding
107 int (* queuecommand)(struct scsi_cmnd *,
108 void (*done)(struct scsi_cmnd *));
111 * This is an error handling strategy routine. You don't need to
112 * define one of these if you don't want to - there is a default
113 * routine that is present that should work in most cases. For those
114 * driver authors that have the inclination and ability to write their
115 * own strategy routine, this is where it is specified. Note - the
116 * strategy routine is *ALWAYS* run in the context of the kernel eh
117 * thread. Thus you are guaranteed to *NOT* be in an interrupt
118 * handler when you execute this, and you are also guaranteed to
119 * *NOT* have any other commands being queued while you are in the
120 * strategy routine. When you return from this function, operations
123 * See scsi_error.c scsi_unjam_host for additional comments about
124 * what this function should and should not be attempting to do.
126 * Status: REQUIRED (at least one of them)
128 int (* eh_strategy_handler)(struct Scsi_Host *);
129 int (* eh_abort_handler)(struct scsi_cmnd *);
130 int (* eh_device_reset_handler)(struct scsi_cmnd *);
131 int (* eh_bus_reset_handler)(struct scsi_cmnd *);
132 int (* eh_host_reset_handler)(struct scsi_cmnd *);
135 * This is an optional routine to notify the host that the scsi
136 * timer just fired. The returns tell the timer routine what to
139 * EH_HANDLED: I fixed the error, please complete the command
140 * EH_RESET_TIMER: I need more time, reset the timer and
141 * begin counting again
142 * EH_NOT_HANDLED Begin normal error recovery
146 enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
149 * Old EH handlers, no longer used. Make them warn the user of old
150 * drivers by using a wrong type
152 * Status: MORE THAN OBSOLETE
155 int (* reset)(int, int);
158 * Before the mid layer attempts to scan for a new device where none
159 * currently exists, it will call this entry in your driver. Should
160 * your driver need to allocate any structs or perform any other init
161 * items in order to send commands to a currently unused target/lun
162 * combo, then this is where you can perform those allocations. This
163 * is specifically so that drivers won't have to perform any kind of
164 * "is this a new device" checks in their queuecommand routine,
165 * thereby making the hot path a bit quicker.
167 * Return values: 0 on success, non-0 on failure
169 * Deallocation: If we didn't find any devices at this ID, you will
170 * get an immediate call to slave_destroy(). If we find something
171 * here then you will get a call to slave_configure(), then the
172 * device will be used for however long it is kept around, then when
173 * the device is removed from the system (or * possibly at reboot
174 * time), you will then get a call to slave_destroy(). This is
175 * assuming you implement slave_configure and slave_destroy.
176 * However, if you allocate memory and hang it off the device struct,
177 * then you must implement the slave_destroy() routine at a minimum
178 * in order to avoid leaking memory
179 * each time a device is tore down.
183 int (* slave_alloc)(struct scsi_device *);
186 * Once the device has responded to an INQUIRY and we know the
187 * device is online, we call into the low level driver with the
188 * struct scsi_device *. If the low level device driver implements
189 * this function, it *must* perform the task of setting the queue
190 * depth on the device. All other tasks are optional and depend
191 * on what the driver supports and various implementation details.
193 * Things currently recommended to be handled at this time include:
195 * 1. Setting the device queue depth. Proper setting of this is
196 * described in the comments for scsi_adjust_queue_depth.
197 * 2. Determining if the device supports the various synchronous
198 * negotiation protocols. The device struct will already have
199 * responded to INQUIRY and the results of the standard items
200 * will have been shoved into the various device flag bits, eg.
201 * device->sdtr will be true if the device supports SDTR messages.
202 * 3. Allocating command structs that the device will need.
203 * 4. Setting the default timeout on this device (if needed).
204 * 5. Anything else the low level driver might want to do on a device
205 * specific setup basis...
206 * 6. Return 0 on success, non-0 on error. The device will be marked
207 * as offline on error so that no access will occur. If you return
208 * non-0, your slave_destroy routine will never get called for this
209 * device, so don't leave any loose memory hanging around, clean
210 * up after yourself before returning non-0
214 int (* slave_configure)(struct scsi_device *);
217 * Immediately prior to deallocating the device and after all activity
218 * has ceased the mid layer calls this point so that the low level
219 * driver may completely detach itself from the scsi device and vice
220 * versa. The low level driver is responsible for freeing any memory
221 * it allocated in the slave_alloc or slave_configure calls.
225 void (* slave_destroy)(struct scsi_device *);
228 * This function determines the bios parameters for a given
229 * harddisk. These tend to be numbers that are made up by
230 * the host adapter. Parameters:
231 * size, device, list (heads, sectors, cylinders)
235 int (* bios_param)(struct scsi_device *, struct block_device *,
239 * Can be used to export driver statistics and other infos to the
240 * world outside the kernel ie. userspace and it also provides an
241 * interface to feed the driver with information.
245 int (*proc_info)(struct Scsi_Host *, char *, char **, off_t, int, int);
248 * Name of proc directory
253 * Used to store the procfs directory if a driver implements the
256 struct proc_dir_entry *proc_dir;
259 * This determines if we will use a non-interrupt driven
260 * or an interrupt driven scheme, It is set to the maximum number
261 * of simultaneous commands a given host adapter will accept.
266 * In many instances, especially where disconnect / reconnect are
267 * supported, our host also has an ID on the SCSI bus. If this is
268 * the case, then it must be reserved. Please set this_id to -1 if
269 * your setup is in single initiator mode, and the host lacks an
275 * This determines the degree to which the host adapter is capable
278 unsigned short sg_tablesize;
281 * If the host adapter has limitations beside segment count
283 unsigned short max_sectors;
286 * dma scatter gather segment boundary limit. a segment crossing this
287 * boundary will be split in two.
289 unsigned long dma_boundary;
292 * This specifies "machine infinity" for host templates which don't
293 * limit the transfer size. Note this limit represents an absolute
294 * maximum, and may be over the transfer limits allowed for
295 * individual devices (e.g. 256 for SCSI-1)
297 #define SCSI_DEFAULT_MAX_SECTORS 1024
300 * True if this host adapter can make good use of linked commands.
301 * This will allow more than one command to be queued to a given
302 * unit on a given host. Set this to the maximum number of command
303 * blocks to be provided for each device. Set this to 1 for one
304 * command block per lun, 2 for two, etc. Do not set this to 0.
305 * You should make sure that the host adapter will do the right thing
306 * before you try setting this above 1.
311 * present contains counter indicating how many boards of this
312 * type were found when we did the scan.
314 unsigned char present;
317 * true if this host adapter uses unchecked DMA onto an ISA bus.
319 unsigned unchecked_isa_dma:1;
322 * true if this host adapter can make good use of clustering.
323 * I originally thought that if the tablesize was large that it
324 * was a waste of CPU cycles to prepare a cluster list, but
325 * it works out that the Buslogic is faster if you use a smaller
326 * number of segments (i.e. use clustering). I guess it is
329 unsigned use_clustering:1;
332 * True for emulated SCSI host adapters (e.g. ATAPI)
337 * True if the low-level driver performs its own reset-settle delays.
339 unsigned skip_settle_delay:1;
342 * Countdown for host blocking with no commands outstanding
344 unsigned int max_host_blocked;
347 * Default value for the blocking. If the queue is empty,
348 * host_blocked counts down in the request_fn until it restarts
349 * host operations as zero is reached.
351 * FIXME: This should probably be a value in the template
353 #define SCSI_DEFAULT_HOST_BLOCKED 7
356 * Pointer to the sysfs class properties for this host, NULL terminated.
358 struct class_device_attribute **shost_attrs;
361 * Pointer to the SCSI device properties for this host, NULL terminated.
363 struct device_attribute **sdev_attrs;
366 * List of hosts per template.
368 * This is only for use by scsi_module.c for legacy templates.
369 * For these access to it is synchronized implicitly by
370 * module_init/module_exit.
372 struct list_head legacy_hosts;
387 * __devices is protected by the host_lock, but you should
388 * usually use scsi_device_lookup / shost_for_each_device
389 * to access it and don't care about locking yourself.
390 * In the rare case of beeing in irq context you can use
391 * their __ prefixed variants with the lock held. NEVER
392 * access this list directly from a driver.
394 struct list_head __devices;
396 struct scsi_host_cmd_pool *cmd_pool;
397 spinlock_t free_list_lock;
398 struct list_head free_list; /* backup store of cmd structs */
399 struct list_head starved_list;
401 spinlock_t default_lock;
402 spinlock_t *host_lock;
404 struct semaphore scan_mutex;/* serialize scanning activity */
406 struct list_head eh_cmd_q;
407 struct task_struct * ehandler; /* Error recovery thread. */
408 struct semaphore * eh_wait; /* The error recovery thread waits
410 struct completion * eh_notify; /* wait for eh to begin or end */
411 struct semaphore * eh_action; /* Wait for specific actions on the
413 unsigned int eh_active:1; /* Indicates the eh thread is awake and active if
415 unsigned int eh_kill:1; /* set when killing the eh thread */
416 wait_queue_head_t host_wait;
417 struct scsi_host_template *hostt;
418 struct scsi_transport_template *transportt;
419 volatile unsigned short host_busy; /* commands actually active on low-level */
420 volatile unsigned short host_failed; /* commands that failed. */
422 unsigned short host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
423 int resetting; /* if set, it means that last_reset is a valid value */
424 unsigned long last_reset;
427 * These three parameters can be used to allow for wide scsi,
428 * and for host adapters that support multiple busses
429 * The first two should be set to 1 more than the actual max id
430 * or lun (i.e. 8 for normal systems).
433 unsigned int max_lun;
434 unsigned int max_channel;
437 * This is a unique identifier that must be assigned so that we
438 * have some way of identifying each detected host adapter properly
439 * and uniquely. For hosts that do not support more than one card
440 * in the system at one time, this does not need to be set. It is
441 * initialized to 0 in scsi_register.
443 unsigned int unique_id;
446 * The maximum length of SCSI commands that this host can accept.
447 * Probably 12 for most host adapters, but could be 16 for others.
448 * For drivers that don't set this field, a value of 12 is
449 * assumed. I am leaving this as a number rather than a bit
450 * because you never know what subsequent SCSI standards might do
451 * (i.e. could there be a 20 byte or a 24-byte command a few years
454 unsigned char max_cmd_len;
459 short unsigned int sg_tablesize;
460 short unsigned int max_sectors;
461 unsigned long dma_boundary;
463 unsigned unchecked_isa_dma:1;
464 unsigned use_clustering:1;
465 unsigned use_blk_tcq:1;
468 * Host has requested that no further requests come through for the
471 unsigned host_self_blocked:1;
474 * Host uses correct SCSI ordering not PC ordering. The bit is
475 * set for the minority of drivers whose authors actually read
478 unsigned reverse_ordering:1;
481 * Host has rejected a command because it was busy.
483 unsigned int host_blocked;
486 * Value host_blocked counts down from
488 unsigned int max_host_blocked;
492 unsigned long io_port;
493 unsigned char n_io_port;
494 unsigned char dma_channel;
498 unsigned long shost_state;
501 struct device shost_gendev;
502 struct class_device shost_classdev;
505 * List of hosts per template.
507 * This is only for use by scsi_module.c for legacy templates.
508 * For these access to it is synchronized implicitly by
509 * module_init/module_exit.
511 struct list_head sht_legacy_list;
514 * We should ensure that this is aligned, both for better performance
515 * and also because some compilers (m68k) don't automatically force
516 * alignment to a long boundary.
518 unsigned long hostdata[0] /* Used for storage of host specific stuff */
519 __attribute__ ((aligned (sizeof(unsigned long))));
521 #define dev_to_shost(d) \
522 container_of(d, struct Scsi_Host, shost_gendev)
523 #define class_to_shost(d) \
524 container_of(d, struct Scsi_Host, shost_classdev)
526 extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int);
527 extern int scsi_add_host(struct Scsi_Host *, struct device *);
528 extern void scsi_scan_host(struct Scsi_Host *);
529 extern void scsi_remove_host(struct Scsi_Host *);
530 extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);
531 extern void scsi_host_put(struct Scsi_Host *t);
532 extern struct Scsi_Host *scsi_host_lookup(unsigned short);
534 extern u64 scsi_calculate_bounce_limit(struct Scsi_Host *);
536 static inline void scsi_assign_lock(struct Scsi_Host *shost, spinlock_t *lock)
538 shost->host_lock = lock;
541 static inline void scsi_set_device(struct Scsi_Host *shost,
544 shost->shost_gendev.parent = dev;
547 static inline struct device *scsi_get_device(struct Scsi_Host *shost)
549 return shost->shost_gendev.parent;
552 extern void scsi_unblock_requests(struct Scsi_Host *);
553 extern void scsi_block_requests(struct Scsi_Host *);
556 * These two functions are used to allocate and free a pseudo device
557 * which will connect to the host adapter itself rather than any
558 * physical device. You must deallocate when you are done with the
559 * thing. This physical pseudo-device isn't real and won't be available
560 * from any high-level drivers.
562 extern void scsi_free_host_dev(struct scsi_device *);
563 extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *);
565 /* legacy interfaces */
566 extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int);
567 extern void scsi_unregister(struct Scsi_Host *);
569 #endif /* _SCSI_SCSI_HOST_H */