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
34 struct scsi_host_template {
35 struct module *module;
39 * Used to initialize old-style drivers. For new-style drivers
40 * just perform all work in your module initialization function.
44 int (* detect)(struct scsi_host_template *);
47 * Used as unload callback for hosts with old-style drivers.
51 int (* release)(struct Scsi_Host *);
54 * The info function will return whatever useful information the
55 * developer sees fit. If not provided, then the name field will
60 const char *(* info)(struct Scsi_Host *);
67 int (* ioctl)(struct scsi_device *dev, int cmd, void *arg);
70 * The queuecommand function is used to queue up a scsi
71 * command block to the LLDD. When the driver finished
72 * processing the command the done callback is invoked.
74 * If queuecommand returns 0, then the HBA has accepted the
75 * command. The done() function must be called on the command
76 * when the driver has finished with it. (you may call done on the
77 * command before queuecommand returns, but in this case you
78 * *must* return 0 from queuecommand).
80 * Queuecommand may also reject the command, in which case it may
81 * not touch the command and must not call done() for it.
83 * There are two possible rejection returns:
85 * SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but
86 * allow commands to other devices serviced by this host.
88 * SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this
91 * For compatibility, any other non-zero return is treated the
92 * same as SCSI_MLQUEUE_HOST_BUSY.
94 * NOTE: "temporarily" means either until the next command for#
95 * this device/host completes, or a period of time determined by
96 * I/O pressure in the system if there are no other outstanding
101 int (* queuecommand)(struct scsi_cmnd *,
102 void (*done)(struct scsi_cmnd *));
105 * This is an error handling strategy routine. You don't need to
106 * define one of these if you don't want to - there is a default
107 * routine that is present that should work in most cases. For those
108 * driver authors that have the inclination and ability to write their
109 * own strategy routine, this is where it is specified. Note - the
110 * strategy routine is *ALWAYS* run in the context of the kernel eh
111 * thread. Thus you are guaranteed to *NOT* be in an interrupt
112 * handler when you execute this, and you are also guaranteed to
113 * *NOT* have any other commands being queued while you are in the
114 * strategy routine. When you return from this function, operations
117 * See scsi_error.c scsi_unjam_host for additional comments about
118 * what this function should and should not be attempting to do.
120 * Status: REQUIRED (at least one of them)
122 int (* eh_strategy_handler)(struct Scsi_Host *);
123 int (* eh_abort_handler)(struct scsi_cmnd *);
124 int (* eh_device_reset_handler)(struct scsi_cmnd *);
125 int (* eh_bus_reset_handler)(struct scsi_cmnd *);
126 int (* eh_host_reset_handler)(struct scsi_cmnd *);
129 * Old EH handlers, no longer used. Make them warn the user of old
130 * drivers by using a wrong type
132 * Status: MORE THAN OBSOLETE
135 int (* reset)(int, int);
138 * Before the mid layer attempts to scan for a new device where none
139 * currently exists, it will call this entry in your driver. Should
140 * your driver need to allocate any structs or perform any other init
141 * items in order to send commands to a currently unused target/lun
142 * combo, then this is where you can perform those allocations. This
143 * is specifically so that drivers won't have to perform any kind of
144 * "is this a new device" checks in their queuecommand routine,
145 * thereby making the hot path a bit quicker.
147 * Return values: 0 on success, non-0 on failure
149 * Deallocation: If we didn't find any devices at this ID, you will
150 * get an immediate call to slave_destroy(). If we find something
151 * here then you will get a call to slave_configure(), then the
152 * device will be used for however long it is kept around, then when
153 * the device is removed from the system (or * possibly at reboot
154 * time), you will then get a call to slave_detach(). This is
155 * assuming you implement slave_configure and slave_destroy.
156 * However, if you allocate memory and hang it off the device struct,
157 * then you must implement the slave_destroy() routine at a minimum
158 * in order to avoid leaking memory
159 * each time a device is tore down.
163 int (* slave_alloc)(struct scsi_device *);
166 * Once the device has responded to an INQUIRY and we know the
167 * device is online, we call into the low level driver with the
168 * struct scsi_device *. If the low level device driver implements
169 * this function, it *must* perform the task of setting the queue
170 * depth on the device. All other tasks are optional and depend
171 * on what the driver supports and various implementation details.
173 * Things currently recommended to be handled at this time include:
175 * 1. Setting the device queue depth. Proper setting of this is
176 * described in the comments for scsi_adjust_queue_depth.
177 * 2. Determining if the device supports the various synchronous
178 * negotiation protocols. The device struct will already have
179 * responded to INQUIRY and the results of the standard items
180 * will have been shoved into the various device flag bits, eg.
181 * device->sdtr will be true if the device supports SDTR messages.
182 * 3. Allocating command structs that the device will need.
183 * 4. Setting the default timeout on this device (if needed).
184 * 5. Anything else the low level driver might want to do on a device
185 * specific setup basis...
186 * 6. Return 0 on success, non-0 on error. The device will be marked
187 * as offline on error so that no access will occur. If you return
188 * non-0, your slave_detach routine will never get called for this
189 * device, so don't leave any loose memory hanging around, clean
190 * up after yourself before returning non-0
194 int (* slave_configure)(struct scsi_device *);
197 * Immediately prior to deallocating the device and after all activity
198 * has ceased the mid layer calls this point so that the low level
199 * driver may completely detach itself from the scsi device and vice
200 * versa. The low level driver is responsible for freeing any memory
201 * it allocated in the slave_alloc or slave_configure calls.
205 void (* slave_destroy)(struct scsi_device *);
208 * This function determines the bios parameters for a given
209 * harddisk. These tend to be numbers that are made up by
210 * the host adapter. Parameters:
211 * size, device, list (heads, sectors, cylinders)
215 int (* bios_param)(struct scsi_device *, struct block_device *,
219 * Can be used to export driver statistics and other infos to the
220 * world outside the kernel ie. userspace and it also provides an
221 * interface to feed the driver with information.
225 int (*proc_info)(struct Scsi_Host *, char *, char **, off_t, int, int);
228 * Name of proc directory
233 * Used to store the procfs directory if a driver implements the
236 struct proc_dir_entry *proc_dir;
239 * This determines if we will use a non-interrupt driven
240 * or an interrupt driven scheme, It is set to the maximum number
241 * of simultaneous commands a given host adapter will accept.
246 * In many instances, especially where disconnect / reconnect are
247 * supported, our host also has an ID on the SCSI bus. If this is
248 * the case, then it must be reserved. Please set this_id to -1 if
249 * your setup is in single initiator mode, and the host lacks an
255 * This determines the degree to which the host adapter is capable
258 unsigned short sg_tablesize;
261 * If the host adapter has limitations beside segment count
263 unsigned short max_sectors;
266 * dma scatter gather segment boundary limit. a segment crossing this
267 * boundary will be split in two.
269 unsigned long dma_boundary;
272 * This specifies "machine infinity" for host templates which don't
273 * limit the transfer size. Note this limit represents an absolute
274 * maximum, and may be over the transfer limits allowed for
275 * individual devices (e.g. 256 for SCSI-1)
277 #define SCSI_DEFAULT_MAX_SECTORS 1024
280 * True if this host adapter can make good use of linked commands.
281 * This will allow more than one command to be queued to a given
282 * unit on a given host. Set this to the maximum number of command
283 * blocks to be provided for each device. Set this to 1 for one
284 * command block per lun, 2 for two, etc. Do not set this to 0.
285 * You should make sure that the host adapter will do the right thing
286 * before you try setting this above 1.
291 * present contains counter indicating how many boards of this
292 * type were found when we did the scan.
294 unsigned char present;
297 * true if this host adapter uses unchecked DMA onto an ISA bus.
299 unsigned unchecked_isa_dma:1;
302 * true if this host adapter can make good use of clustering.
303 * I originally thought that if the tablesize was large that it
304 * was a waste of CPU cycles to prepare a cluster list, but
305 * it works out that the Buslogic is faster if you use a smaller
306 * number of segments (i.e. use clustering). I guess it is
309 unsigned use_clustering:1;
312 * True for emulated SCSI host adapters (e.g. ATAPI)
317 * Countdown for host blocking with no commands outstanding
319 unsigned int max_host_blocked;
322 * Default value for the blocking. If the queue is empty,
323 * host_blocked counts down in the request_fn until it restarts
324 * host operations as zero is reached.
326 * FIXME: This should probably be a value in the template
328 #define SCSI_DEFAULT_HOST_BLOCKED 7
331 * Pointer to the sysfs class properties for this host, NULL terminated.
333 struct class_device_attribute **shost_attrs;
336 * Pointer to the SCSI device properties for this host, NULL terminated.
338 struct device_attribute **sdev_attrs;
341 * List of hosts per template.
343 * This is only for use by scsi_module.c for legacy templates.
344 * For these access to it is synchronized implicitly by
345 * module_init/module_exit.
347 struct list_head legacy_hosts;
362 * __devices is protected by the host_lock, but you should
363 * usually use scsi_device_lookup / shost_for_each_device
364 * to access it and don't care about locking yourself.
365 * In the rare case of beeing in irq context you can use
366 * their __ prefixed variants with the lock held. NEVER
367 * access this list directly from a driver.
369 struct list_head __devices;
371 struct scsi_host_cmd_pool *cmd_pool;
372 spinlock_t free_list_lock;
373 struct list_head free_list; /* backup store of cmd structs */
374 struct list_head starved_list;
376 spinlock_t default_lock;
377 spinlock_t *host_lock;
379 struct semaphore scan_mutex;/* serialize scanning activity */
381 struct list_head eh_cmd_q;
382 struct task_struct * ehandler; /* Error recovery thread. */
383 struct semaphore * eh_wait; /* The error recovery thread waits
385 struct completion * eh_notify; /* wait for eh to begin or end */
386 struct semaphore * eh_action; /* Wait for specific actions on the
388 unsigned int eh_active:1; /* Indicates the eh thread is awake and active if
390 unsigned int eh_kill:1; /* set when killing the eh thread */
391 wait_queue_head_t host_wait;
392 struct scsi_host_template *hostt;
393 struct scsi_transport_template *transportt;
394 volatile unsigned short host_busy; /* commands actually active on low-level */
395 volatile unsigned short host_failed; /* commands that failed. */
397 unsigned short host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
398 int resetting; /* if set, it means that last_reset is a valid value */
399 unsigned long last_reset;
402 * These three parameters can be used to allow for wide scsi,
403 * and for host adapters that support multiple busses
404 * The first two should be set to 1 more than the actual max id
405 * or lun (i.e. 8 for normal systems).
408 unsigned int max_lun;
409 unsigned int max_channel;
412 * This is a unique identifier that must be assigned so that we
413 * have some way of identifying each detected host adapter properly
414 * and uniquely. For hosts that do not support more than one card
415 * in the system at one time, this does not need to be set. It is
416 * initialized to 0 in scsi_register.
418 unsigned int unique_id;
421 * The maximum length of SCSI commands that this host can accept.
422 * Probably 12 for most host adapters, but could be 16 for others.
423 * For drivers that don't set this field, a value of 12 is
424 * assumed. I am leaving this as a number rather than a bit
425 * because you never know what subsequent SCSI standards might do
426 * (i.e. could there be a 20 byte or a 24-byte command a few years
429 unsigned char max_cmd_len;
434 short unsigned int sg_tablesize;
435 short unsigned int max_sectors;
436 unsigned long dma_boundary;
438 unsigned unchecked_isa_dma:1;
439 unsigned use_clustering:1;
440 unsigned use_blk_tcq:1;
443 * Host has requested that no further requests come through for the
446 unsigned host_self_blocked:1;
449 * Host uses correct SCSI ordering not PC ordering. The bit is
450 * set for the minority of drivers whose authors actually read
453 unsigned reverse_ordering:1;
456 * Host has rejected a command because it was busy.
458 unsigned int host_blocked;
461 * Value host_blocked counts down from
463 unsigned int max_host_blocked;
467 unsigned long io_port;
468 unsigned char n_io_port;
469 unsigned char dma_channel;
473 unsigned long shost_state;
476 struct device shost_gendev;
477 struct class_device shost_classdev;
480 * List of hosts per template.
482 * This is only for use by scsi_module.c for legacy templates.
483 * For these access to it is synchronized implicitly by
484 * module_init/module_exit.
486 struct list_head sht_legacy_list;
489 * We should ensure that this is aligned, both for better performance
490 * and also because some compilers (m68k) don't automatically force
491 * alignment to a long boundary.
493 unsigned long hostdata[0] /* Used for storage of host specific stuff */
494 __attribute__ ((aligned (sizeof(unsigned long))));
496 #define dev_to_shost(d) \
497 container_of(d, struct Scsi_Host, shost_gendev)
498 #define class_to_shost(d) \
499 container_of(d, struct Scsi_Host, shost_classdev)
501 extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int);
502 extern int scsi_add_host(struct Scsi_Host *, struct device *);
503 extern void scsi_scan_host(struct Scsi_Host *);
504 extern void scsi_remove_host(struct Scsi_Host *);
505 extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);
506 extern void scsi_host_put(struct Scsi_Host *t);
507 extern struct Scsi_Host *scsi_host_lookup(unsigned short);
509 extern u64 scsi_calculate_bounce_limit(struct Scsi_Host *);
511 static inline void scsi_assign_lock(struct Scsi_Host *shost, spinlock_t *lock)
513 shost->host_lock = lock;
516 static inline void scsi_set_device(struct Scsi_Host *shost,
519 shost->shost_gendev.parent = dev;
522 static inline struct device *scsi_get_device(struct Scsi_Host *shost)
524 return shost->shost_gendev.parent;
527 extern void scsi_unblock_requests(struct Scsi_Host *);
528 extern void scsi_block_requests(struct Scsi_Host *);
531 * These two functions are used to allocate and free a pseudo device
532 * which will connect to the host adapter itself rather than any
533 * physical device. You must deallocate when you are done with the
534 * thing. This physical pseudo-device isn't real and won't be available
535 * from any high-level drivers.
537 extern void scsi_free_host_dev(struct scsi_device *);
538 extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *);
540 /* legacy interfaces */
541 extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int);
542 extern void scsi_unregister(struct Scsi_Host *);
544 #endif /* _SCSI_SCSI_HOST_H */