1 #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 #include <linux/mutex.h> 9 10 struct block_device; 11 struct completion; 12 struct module; 13 struct scsi_cmnd; 14 struct scsi_device; 15 struct scsi_target; 16 struct Scsi_Host; 17 struct scsi_host_cmd_pool; 18 struct scsi_transport_template; 19 20 21 /* 22 * The various choices mean: 23 * NONE: Self evident. Host adapter is not capable of scatter-gather. 24 * ALL: Means that the host adapter module can do scatter-gather, 25 * and that there is no limit to the size of the table to which 26 * we scatter/gather data. 27 * Anything else: Indicates the maximum number of chains that can be 28 * used in one scatter-gather request. 29 */ 30 #define SG_NONE 0 31 #define SG_ALL 0xff 32 33 34 #define DISABLE_CLUSTERING 0 35 #define ENABLE_CLUSTERING 1 36 37 enum scsi_eh_timer_return { 38 EH_NOT_HANDLED, 39 EH_HANDLED, 40 EH_RESET_TIMER, 41 }; 42 43 44 struct scsi_host_template { 45 struct module *module; 46 const char *name; 47 48 /* 49 * Used to initialize old-style drivers. For new-style drivers 50 * just perform all work in your module initialization function. 51 * 52 * Status: OBSOLETE 53 */ 54 int (* detect)(struct scsi_host_template *); 55 56 /* 57 * Used as unload callback for hosts with old-style drivers. 58 * 59 * Status: OBSOLETE 60 */ 61 int (* release)(struct Scsi_Host *); 62 63 /* 64 * The info function will return whatever useful information the 65 * developer sees fit. If not provided, then the name field will 66 * be used instead. 67 * 68 * Status: OPTIONAL 69 */ 70 const char *(* info)(struct Scsi_Host *); 71 72 /* 73 * Ioctl interface 74 * 75 * Status: OPTIONAL 76 */ 77 int (* ioctl)(struct scsi_device *dev, int cmd, void __user *arg); 78 79 80 #ifdef CONFIG_COMPAT 81 /* 82 * Compat handler. Handle 32bit ABI. 83 * When unknown ioctl is passed return -ENOIOCTLCMD. 84 * 85 * Status: OPTIONAL 86 */ 87 int (* compat_ioctl)(struct scsi_device *dev, int cmd, void __user *arg); 88 #endif 89 90 /* 91 * The queuecommand function is used to queue up a scsi 92 * command block to the LLDD. When the driver finished 93 * processing the command the done callback is invoked. 94 * 95 * If queuecommand returns 0, then the HBA has accepted the 96 * command. The done() function must be called on the command 97 * when the driver has finished with it. (you may call done on the 98 * command before queuecommand returns, but in this case you 99 * *must* return 0 from queuecommand). 100 * 101 * Queuecommand may also reject the command, in which case it may 102 * not touch the command and must not call done() for it. 103 * 104 * There are two possible rejection returns: 105 * 106 * SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but 107 * allow commands to other devices serviced by this host. 108 * 109 * SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this 110 * host temporarily. 111 * 112 * For compatibility, any other non-zero return is treated the 113 * same as SCSI_MLQUEUE_HOST_BUSY. 114 * 115 * NOTE: "temporarily" means either until the next command for# 116 * this device/host completes, or a period of time determined by 117 * I/O pressure in the system if there are no other outstanding 118 * commands. 119 * 120 * STATUS: REQUIRED 121 */ 122 int (* queuecommand)(struct scsi_cmnd *, 123 void (*done)(struct scsi_cmnd *)); 124 125 /* 126 * This is an error handling strategy routine. You don't need to 127 * define one of these if you don't want to - there is a default 128 * routine that is present that should work in most cases. For those 129 * driver authors that have the inclination and ability to write their 130 * own strategy routine, this is where it is specified. Note - the 131 * strategy routine is *ALWAYS* run in the context of the kernel eh 132 * thread. Thus you are guaranteed to *NOT* be in an interrupt 133 * handler when you execute this, and you are also guaranteed to 134 * *NOT* have any other commands being queued while you are in the 135 * strategy routine. When you return from this function, operations 136 * return to normal. 137 * 138 * See scsi_error.c scsi_unjam_host for additional comments about 139 * what this function should and should not be attempting to do. 140 * 141 * Status: REQUIRED (at least one of them) 142 */ 143 int (* eh_abort_handler)(struct scsi_cmnd *); 144 int (* eh_device_reset_handler)(struct scsi_cmnd *); 145 int (* eh_bus_reset_handler)(struct scsi_cmnd *); 146 int (* eh_host_reset_handler)(struct scsi_cmnd *); 147 148 /* 149 * Before the mid layer attempts to scan for a new device where none 150 * currently exists, it will call this entry in your driver. Should 151 * your driver need to allocate any structs or perform any other init 152 * items in order to send commands to a currently unused target/lun 153 * combo, then this is where you can perform those allocations. This 154 * is specifically so that drivers won't have to perform any kind of 155 * "is this a new device" checks in their queuecommand routine, 156 * thereby making the hot path a bit quicker. 157 * 158 * Return values: 0 on success, non-0 on failure 159 * 160 * Deallocation: If we didn't find any devices at this ID, you will 161 * get an immediate call to slave_destroy(). If we find something 162 * here then you will get a call to slave_configure(), then the 163 * device will be used for however long it is kept around, then when 164 * the device is removed from the system (or * possibly at reboot 165 * time), you will then get a call to slave_destroy(). This is 166 * assuming you implement slave_configure and slave_destroy. 167 * However, if you allocate memory and hang it off the device struct, 168 * then you must implement the slave_destroy() routine at a minimum 169 * in order to avoid leaking memory 170 * each time a device is tore down. 171 * 172 * Status: OPTIONAL 173 */ 174 int (* slave_alloc)(struct scsi_device *); 175 176 /* 177 * Once the device has responded to an INQUIRY and we know the 178 * device is online, we call into the low level driver with the 179 * struct scsi_device *. If the low level device driver implements 180 * this function, it *must* perform the task of setting the queue 181 * depth on the device. All other tasks are optional and depend 182 * on what the driver supports and various implementation details. 183 * 184 * Things currently recommended to be handled at this time include: 185 * 186 * 1. Setting the device queue depth. Proper setting of this is 187 * described in the comments for scsi_adjust_queue_depth. 188 * 2. Determining if the device supports the various synchronous 189 * negotiation protocols. The device struct will already have 190 * responded to INQUIRY and the results of the standard items 191 * will have been shoved into the various device flag bits, eg. 192 * device->sdtr will be true if the device supports SDTR messages. 193 * 3. Allocating command structs that the device will need. 194 * 4. Setting the default timeout on this device (if needed). 195 * 5. Anything else the low level driver might want to do on a device 196 * specific setup basis... 197 * 6. Return 0 on success, non-0 on error. The device will be marked 198 * as offline on error so that no access will occur. If you return 199 * non-0, your slave_destroy routine will never get called for this 200 * device, so don't leave any loose memory hanging around, clean 201 * up after yourself before returning non-0 202 * 203 * Status: OPTIONAL 204 */ 205 int (* slave_configure)(struct scsi_device *); 206 207 /* 208 * Immediately prior to deallocating the device and after all activity 209 * has ceased the mid layer calls this point so that the low level 210 * driver may completely detach itself from the scsi device and vice 211 * versa. The low level driver is responsible for freeing any memory 212 * it allocated in the slave_alloc or slave_configure calls. 213 * 214 * Status: OPTIONAL 215 */ 216 void (* slave_destroy)(struct scsi_device *); 217 218 /* 219 * Before the mid layer attempts to scan for a new device attached 220 * to a target where no target currently exists, it will call this 221 * entry in your driver. Should your driver need to allocate any 222 * structs or perform any other init items in order to send commands 223 * to a currently unused target, then this is where you can perform 224 * those allocations. 225 * 226 * Return values: 0 on success, non-0 on failure 227 * 228 * Status: OPTIONAL 229 */ 230 int (* target_alloc)(struct scsi_target *); 231 232 /* 233 * Immediately prior to deallocating the target structure, and 234 * after all activity to attached scsi devices has ceased, the 235 * midlayer calls this point so that the driver may deallocate 236 * and terminate any references to the target. 237 * 238 * Status: OPTIONAL 239 */ 240 void (* target_destroy)(struct scsi_target *); 241 242 /* 243 * fill in this function to allow the queue depth of this host 244 * to be changeable (on a per device basis). returns either 245 * the current queue depth setting (may be different from what 246 * was passed in) or an error. An error should only be 247 * returned if the requested depth is legal but the driver was 248 * unable to set it. If the requested depth is illegal, the 249 * driver should set and return the closest legal queue depth. 250 * 251 */ 252 int (* change_queue_depth)(struct scsi_device *, int); 253 254 /* 255 * fill in this function to allow the changing of tag types 256 * (this also allows the enabling/disabling of tag command 257 * queueing). An error should only be returned if something 258 * went wrong in the driver while trying to set the tag type. 259 * If the driver doesn't support the requested tag type, then 260 * it should set the closest type it does support without 261 * returning an error. Returns the actual tag type set. 262 */ 263 int (* change_queue_type)(struct scsi_device *, int); 264 265 /* 266 * This function determines the bios parameters for a given 267 * harddisk. These tend to be numbers that are made up by 268 * the host adapter. Parameters: 269 * size, device, list (heads, sectors, cylinders) 270 * 271 * Status: OPTIONAL */ 272 int (* bios_param)(struct scsi_device *, struct block_device *, 273 sector_t, int []); 274 275 /* 276 * Can be used to export driver statistics and other infos to the 277 * world outside the kernel ie. userspace and it also provides an 278 * interface to feed the driver with information. 279 * 280 * Status: OBSOLETE 281 */ 282 int (*proc_info)(struct Scsi_Host *, char *, char **, off_t, int, int); 283 284 /* 285 * suspend support 286 */ 287 int (*resume)(struct scsi_device *); 288 int (*suspend)(struct scsi_device *, pm_message_t state); 289 290 /* 291 * Name of proc directory 292 */ 293 char *proc_name; 294 295 /* 296 * Used to store the procfs directory if a driver implements the 297 * proc_info method. 298 */ 299 struct proc_dir_entry *proc_dir; 300 301 /* 302 * This determines if we will use a non-interrupt driven 303 * or an interrupt driven scheme, It is set to the maximum number 304 * of simultaneous commands a given host adapter will accept. 305 */ 306 int can_queue; 307 308 /* 309 * In many instances, especially where disconnect / reconnect are 310 * supported, our host also has an ID on the SCSI bus. If this is 311 * the case, then it must be reserved. Please set this_id to -1 if 312 * your setup is in single initiator mode, and the host lacks an 313 * ID. 314 */ 315 int this_id; 316 317 /* 318 * This determines the degree to which the host adapter is capable 319 * of scatter-gather. 320 */ 321 unsigned short sg_tablesize; 322 323 /* 324 * If the host adapter has limitations beside segment count 325 */ 326 unsigned short max_sectors; 327 328 /* 329 * dma scatter gather segment boundary limit. a segment crossing this 330 * boundary will be split in two. 331 */ 332 unsigned long dma_boundary; 333 334 /* 335 * This specifies "machine infinity" for host templates which don't 336 * limit the transfer size. Note this limit represents an absolute 337 * maximum, and may be over the transfer limits allowed for 338 * individual devices (e.g. 256 for SCSI-1) 339 */ 340 #define SCSI_DEFAULT_MAX_SECTORS 1024 341 342 /* 343 * True if this host adapter can make good use of linked commands. 344 * This will allow more than one command to be queued to a given 345 * unit on a given host. Set this to the maximum number of command 346 * blocks to be provided for each device. Set this to 1 for one 347 * command block per lun, 2 for two, etc. Do not set this to 0. 348 * You should make sure that the host adapter will do the right thing 349 * before you try setting this above 1. 350 */ 351 short cmd_per_lun; 352 353 /* 354 * present contains counter indicating how many boards of this 355 * type were found when we did the scan. 356 */ 357 unsigned char present; 358 359 /* 360 * true if this host adapter uses unchecked DMA onto an ISA bus. 361 */ 362 unsigned unchecked_isa_dma:1; 363 364 /* 365 * true if this host adapter can make good use of clustering. 366 * I originally thought that if the tablesize was large that it 367 * was a waste of CPU cycles to prepare a cluster list, but 368 * it works out that the Buslogic is faster if you use a smaller 369 * number of segments (i.e. use clustering). I guess it is 370 * inefficient. 371 */ 372 unsigned use_clustering:1; 373 374 /* 375 * True for emulated SCSI host adapters (e.g. ATAPI) 376 */ 377 unsigned emulated:1; 378 379 /* 380 * True if the low-level driver performs its own reset-settle delays. 381 */ 382 unsigned skip_settle_delay:1; 383 384 /* 385 * ordered write support 386 */ 387 unsigned ordered_tag:1; 388 389 /* 390 * Countdown for host blocking with no commands outstanding 391 */ 392 unsigned int max_host_blocked; 393 394 /* 395 * Default value for the blocking. If the queue is empty, 396 * host_blocked counts down in the request_fn until it restarts 397 * host operations as zero is reached. 398 * 399 * FIXME: This should probably be a value in the template 400 */ 401 #define SCSI_DEFAULT_HOST_BLOCKED 7 402 403 /* 404 * Pointer to the sysfs class properties for this host, NULL terminated. 405 */ 406 struct class_device_attribute **shost_attrs; 407 408 /* 409 * Pointer to the SCSI device properties for this host, NULL terminated. 410 */ 411 struct device_attribute **sdev_attrs; 412 413 /* 414 * List of hosts per template. 415 * 416 * This is only for use by scsi_module.c for legacy templates. 417 * For these access to it is synchronized implicitly by 418 * module_init/module_exit. 419 */ 420 struct list_head legacy_hosts; 421 }; 422 423 /* 424 * shost state: If you alter this, you also need to alter scsi_sysfs.c 425 * (for the ascii descriptions) and the state model enforcer: 426 * scsi_host_set_state() 427 */ 428 enum scsi_host_state { 429 SHOST_CREATED = 1, 430 SHOST_RUNNING, 431 SHOST_CANCEL, 432 SHOST_DEL, 433 SHOST_RECOVERY, 434 SHOST_CANCEL_RECOVERY, 435 SHOST_DEL_RECOVERY, 436 }; 437 438 struct Scsi_Host { 439 /* 440 * __devices is protected by the host_lock, but you should 441 * usually use scsi_device_lookup / shost_for_each_device 442 * to access it and don't care about locking yourself. 443 * In the rare case of beeing in irq context you can use 444 * their __ prefixed variants with the lock held. NEVER 445 * access this list directly from a driver. 446 */ 447 struct list_head __devices; 448 struct list_head __targets; 449 450 struct scsi_host_cmd_pool *cmd_pool; 451 spinlock_t free_list_lock; 452 struct list_head free_list; /* backup store of cmd structs */ 453 struct list_head starved_list; 454 455 spinlock_t default_lock; 456 spinlock_t *host_lock; 457 458 struct mutex scan_mutex;/* serialize scanning activity */ 459 460 struct list_head eh_cmd_q; 461 struct task_struct * ehandler; /* Error recovery thread. */ 462 struct completion * eh_action; /* Wait for specific actions on the 463 host. */ 464 wait_queue_head_t host_wait; 465 struct scsi_host_template *hostt; 466 struct scsi_transport_template *transportt; 467 468 /* 469 * The following two fields are protected with host_lock; 470 * however, eh routines can safely access during eh processing 471 * without acquiring the lock. 472 */ 473 unsigned int host_busy; /* commands actually active on low-level */ 474 unsigned int host_failed; /* commands that failed. */ 475 476 unsigned short host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */ 477 int resetting; /* if set, it means that last_reset is a valid value */ 478 unsigned long last_reset; 479 480 /* 481 * These three parameters can be used to allow for wide scsi, 482 * and for host adapters that support multiple busses 483 * The first two should be set to 1 more than the actual max id 484 * or lun (i.e. 8 for normal systems). 485 */ 486 unsigned int max_id; 487 unsigned int max_lun; 488 unsigned int max_channel; 489 490 /* 491 * This is a unique identifier that must be assigned so that we 492 * have some way of identifying each detected host adapter properly 493 * and uniquely. For hosts that do not support more than one card 494 * in the system at one time, this does not need to be set. It is 495 * initialized to 0 in scsi_register. 496 */ 497 unsigned int unique_id; 498 499 /* 500 * The maximum length of SCSI commands that this host can accept. 501 * Probably 12 for most host adapters, but could be 16 for others. 502 * For drivers that don't set this field, a value of 12 is 503 * assumed. I am leaving this as a number rather than a bit 504 * because you never know what subsequent SCSI standards might do 505 * (i.e. could there be a 20 byte or a 24-byte command a few years 506 * down the road?). 507 */ 508 unsigned char max_cmd_len; 509 510 int this_id; 511 int can_queue; 512 short cmd_per_lun; 513 short unsigned int sg_tablesize; 514 short unsigned int max_sectors; 515 unsigned long dma_boundary; 516 /* 517 * Used to assign serial numbers to the cmds. 518 * Protected by the host lock. 519 */ 520 unsigned long cmd_serial_number, cmd_pid; 521 522 unsigned unchecked_isa_dma:1; 523 unsigned use_clustering:1; 524 unsigned use_blk_tcq:1; 525 526 /* 527 * Host has requested that no further requests come through for the 528 * time being. 529 */ 530 unsigned host_self_blocked:1; 531 532 /* 533 * Host uses correct SCSI ordering not PC ordering. The bit is 534 * set for the minority of drivers whose authors actually read 535 * the spec ;) 536 */ 537 unsigned reverse_ordering:1; 538 539 /* 540 * ordered write support 541 */ 542 unsigned ordered_tag:1; 543 544 /* 545 * Optional work queue to be utilized by the transport 546 */ 547 char work_q_name[KOBJ_NAME_LEN]; 548 struct workqueue_struct *work_q; 549 550 /* 551 * Host has rejected a command because it was busy. 552 */ 553 unsigned int host_blocked; 554 555 /* 556 * Value host_blocked counts down from 557 */ 558 unsigned int max_host_blocked; 559 560 /* legacy crap */ 561 unsigned long base; 562 unsigned long io_port; 563 unsigned char n_io_port; 564 unsigned char dma_channel; 565 unsigned int irq; 566 567 568 enum scsi_host_state shost_state; 569 570 /* ldm bits */ 571 struct device shost_gendev; 572 struct class_device shost_classdev; 573 574 /* 575 * List of hosts per template. 576 * 577 * This is only for use by scsi_module.c for legacy templates. 578 * For these access to it is synchronized implicitly by 579 * module_init/module_exit. 580 */ 581 struct list_head sht_legacy_list; 582 583 /* 584 * Points to the transport data (if any) which is allocated 585 * separately 586 */ 587 void *shost_data; 588 589 /* 590 * We should ensure that this is aligned, both for better performance 591 * and also because some compilers (m68k) don't automatically force 592 * alignment to a long boundary. 593 */ 594 unsigned long hostdata[0] /* Used for storage of host specific stuff */ 595 __attribute__ ((aligned (sizeof(unsigned long)))); 596 }; 597 598 #define class_to_shost(d) \ 599 container_of(d, struct Scsi_Host, shost_classdev) 600 601 #define shost_printk(prefix, shost, fmt, a...) \ 602 dev_printk(prefix, &(shost)->shost_gendev, fmt, ##a) 603 604 605 int scsi_is_host_device(const struct device *); 606 607 static inline struct Scsi_Host *dev_to_shost(struct device *dev) 608 { 609 while (!scsi_is_host_device(dev)) { 610 if (!dev->parent) 611 return NULL; 612 dev = dev->parent; 613 } 614 return container_of(dev, struct Scsi_Host, shost_gendev); 615 } 616 617 static inline int scsi_host_in_recovery(struct Scsi_Host *shost) 618 { 619 return shost->shost_state == SHOST_RECOVERY || 620 shost->shost_state == SHOST_CANCEL_RECOVERY || 621 shost->shost_state == SHOST_DEL_RECOVERY; 622 } 623 624 extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *); 625 extern void scsi_flush_work(struct Scsi_Host *); 626 627 extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int); 628 extern int __must_check scsi_add_host(struct Scsi_Host *, struct device *); 629 extern void scsi_scan_host(struct Scsi_Host *); 630 extern void scsi_rescan_device(struct device *); 631 extern void scsi_remove_host(struct Scsi_Host *); 632 extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *); 633 extern void scsi_host_put(struct Scsi_Host *t); 634 extern struct Scsi_Host *scsi_host_lookup(unsigned short); 635 extern const char *scsi_host_state_name(enum scsi_host_state); 636 637 extern u64 scsi_calculate_bounce_limit(struct Scsi_Host *); 638 639 static inline void scsi_assign_lock(struct Scsi_Host *shost, spinlock_t *lock) 640 { 641 shost->host_lock = lock; 642 } 643 644 static inline struct device *scsi_get_device(struct Scsi_Host *shost) 645 { 646 return shost->shost_gendev.parent; 647 } 648 649 /** 650 * scsi_host_scan_allowed - Is scanning of this host allowed 651 * @shost: Pointer to Scsi_Host. 652 **/ 653 static inline int scsi_host_scan_allowed(struct Scsi_Host *shost) 654 { 655 return shost->shost_state == SHOST_RUNNING; 656 } 657 658 extern void scsi_unblock_requests(struct Scsi_Host *); 659 extern void scsi_block_requests(struct Scsi_Host *); 660 661 struct class_container; 662 /* 663 * These two functions are used to allocate and free a pseudo device 664 * which will connect to the host adapter itself rather than any 665 * physical device. You must deallocate when you are done with the 666 * thing. This physical pseudo-device isn't real and won't be available 667 * from any high-level drivers. 668 */ 669 extern void scsi_free_host_dev(struct scsi_device *); 670 extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *); 671 672 /* legacy interfaces */ 673 extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int); 674 extern void scsi_unregister(struct Scsi_Host *); 675 extern int scsi_host_set_state(struct Scsi_Host *, enum scsi_host_state); 676 677 #endif /* _SCSI_SCSI_HOST_H */ 678