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 9 struct block_device; 10 struct completion; 11 struct module; 12 struct scsi_cmnd; 13 struct scsi_device; 14 struct scsi_target; 15 struct Scsi_Host; 16 struct scsi_host_cmd_pool; 17 struct scsi_transport_template; 18 19 20 /* 21 * The various choices mean: 22 * NONE: Self evident. Host adapter is not capable of scatter-gather. 23 * ALL: Means that the host adapter module can do scatter-gather, 24 * and that there is no limit to the size of the table to which 25 * we scatter/gather data. 26 * Anything else: Indicates the maximum number of chains that can be 27 * used in one scatter-gather request. 28 */ 29 #define SG_NONE 0 30 #define SG_ALL 0xff 31 32 33 #define DISABLE_CLUSTERING 0 34 #define ENABLE_CLUSTERING 1 35 36 enum scsi_eh_timer_return { 37 EH_NOT_HANDLED, 38 EH_HANDLED, 39 EH_RESET_TIMER, 40 }; 41 42 43 struct scsi_host_template { 44 struct module *module; 45 const char *name; 46 47 /* 48 * Used to initialize old-style drivers. For new-style drivers 49 * just perform all work in your module initialization function. 50 * 51 * Status: OBSOLETE 52 */ 53 int (* detect)(struct scsi_host_template *); 54 55 /* 56 * Used as unload callback for hosts with old-style drivers. 57 * 58 * Status: OBSOLETE 59 */ 60 int (* release)(struct Scsi_Host *); 61 62 /* 63 * The info function will return whatever useful information the 64 * developer sees fit. If not provided, then the name field will 65 * be used instead. 66 * 67 * Status: OPTIONAL 68 */ 69 const char *(* info)(struct Scsi_Host *); 70 71 /* 72 * Ioctl interface 73 * 74 * Status: OPTIONAL 75 */ 76 int (* ioctl)(struct scsi_device *dev, int cmd, void __user *arg); 77 78 79 #ifdef CONFIG_COMPAT 80 /* 81 * Compat handler. Handle 32bit ABI. 82 * When unknown ioctl is passed return -ENOIOCTLCMD. 83 * 84 * Status: OPTIONAL 85 */ 86 int (* compat_ioctl)(struct scsi_device *dev, int cmd, void __user *arg); 87 #endif 88 89 /* 90 * The queuecommand function is used to queue up a scsi 91 * command block to the LLDD. When the driver finished 92 * processing the command the done callback is invoked. 93 * 94 * If queuecommand returns 0, then the HBA has accepted the 95 * command. The done() function must be called on the command 96 * when the driver has finished with it. (you may call done on the 97 * command before queuecommand returns, but in this case you 98 * *must* return 0 from queuecommand). 99 * 100 * Queuecommand may also reject the command, in which case it may 101 * not touch the command and must not call done() for it. 102 * 103 * There are two possible rejection returns: 104 * 105 * SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but 106 * allow commands to other devices serviced by this host. 107 * 108 * SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this 109 * host temporarily. 110 * 111 * For compatibility, any other non-zero return is treated the 112 * same as SCSI_MLQUEUE_HOST_BUSY. 113 * 114 * NOTE: "temporarily" means either until the next command for# 115 * this device/host completes, or a period of time determined by 116 * I/O pressure in the system if there are no other outstanding 117 * commands. 118 * 119 * STATUS: REQUIRED 120 */ 121 int (* queuecommand)(struct scsi_cmnd *, 122 void (*done)(struct scsi_cmnd *)); 123 124 /* 125 * This is an error handling strategy routine. You don't need to 126 * define one of these if you don't want to - there is a default 127 * routine that is present that should work in most cases. For those 128 * driver authors that have the inclination and ability to write their 129 * own strategy routine, this is where it is specified. Note - the 130 * strategy routine is *ALWAYS* run in the context of the kernel eh 131 * thread. Thus you are guaranteed to *NOT* be in an interrupt 132 * handler when you execute this, and you are also guaranteed to 133 * *NOT* have any other commands being queued while you are in the 134 * strategy routine. When you return from this function, operations 135 * return to normal. 136 * 137 * See scsi_error.c scsi_unjam_host for additional comments about 138 * what this function should and should not be attempting to do. 139 * 140 * Status: REQUIRED (at least one of them) 141 */ 142 int (* eh_strategy_handler)(struct Scsi_Host *); 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 * This is an optional routine to notify the host that the scsi 150 * timer just fired. The returns tell the timer routine what to 151 * do about this: 152 * 153 * EH_HANDLED: I fixed the error, please complete the command 154 * EH_RESET_TIMER: I need more time, reset the timer and 155 * begin counting again 156 * EH_NOT_HANDLED Begin normal error recovery 157 * 158 * Status: OPTIONAL 159 */ 160 enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *); 161 162 /* 163 * Before the mid layer attempts to scan for a new device where none 164 * currently exists, it will call this entry in your driver. Should 165 * your driver need to allocate any structs or perform any other init 166 * items in order to send commands to a currently unused target/lun 167 * combo, then this is where you can perform those allocations. This 168 * is specifically so that drivers won't have to perform any kind of 169 * "is this a new device" checks in their queuecommand routine, 170 * thereby making the hot path a bit quicker. 171 * 172 * Return values: 0 on success, non-0 on failure 173 * 174 * Deallocation: If we didn't find any devices at this ID, you will 175 * get an immediate call to slave_destroy(). If we find something 176 * here then you will get a call to slave_configure(), then the 177 * device will be used for however long it is kept around, then when 178 * the device is removed from the system (or * possibly at reboot 179 * time), you will then get a call to slave_destroy(). This is 180 * assuming you implement slave_configure and slave_destroy. 181 * However, if you allocate memory and hang it off the device struct, 182 * then you must implement the slave_destroy() routine at a minimum 183 * in order to avoid leaking memory 184 * each time a device is tore down. 185 * 186 * Status: OPTIONAL 187 */ 188 int (* slave_alloc)(struct scsi_device *); 189 190 /* 191 * Once the device has responded to an INQUIRY and we know the 192 * device is online, we call into the low level driver with the 193 * struct scsi_device *. If the low level device driver implements 194 * this function, it *must* perform the task of setting the queue 195 * depth on the device. All other tasks are optional and depend 196 * on what the driver supports and various implementation details. 197 * 198 * Things currently recommended to be handled at this time include: 199 * 200 * 1. Setting the device queue depth. Proper setting of this is 201 * described in the comments for scsi_adjust_queue_depth. 202 * 2. Determining if the device supports the various synchronous 203 * negotiation protocols. The device struct will already have 204 * responded to INQUIRY and the results of the standard items 205 * will have been shoved into the various device flag bits, eg. 206 * device->sdtr will be true if the device supports SDTR messages. 207 * 3. Allocating command structs that the device will need. 208 * 4. Setting the default timeout on this device (if needed). 209 * 5. Anything else the low level driver might want to do on a device 210 * specific setup basis... 211 * 6. Return 0 on success, non-0 on error. The device will be marked 212 * as offline on error so that no access will occur. If you return 213 * non-0, your slave_destroy routine will never get called for this 214 * device, so don't leave any loose memory hanging around, clean 215 * up after yourself before returning non-0 216 * 217 * Status: OPTIONAL 218 */ 219 int (* slave_configure)(struct scsi_device *); 220 221 /* 222 * Immediately prior to deallocating the device and after all activity 223 * has ceased the mid layer calls this point so that the low level 224 * driver may completely detach itself from the scsi device and vice 225 * versa. The low level driver is responsible for freeing any memory 226 * it allocated in the slave_alloc or slave_configure calls. 227 * 228 * Status: OPTIONAL 229 */ 230 void (* slave_destroy)(struct scsi_device *); 231 232 /* 233 * Before the mid layer attempts to scan for a new device attached 234 * to a target where no target currently exists, it will call this 235 * entry in your driver. Should your driver need to allocate any 236 * structs or perform any other init items in order to send commands 237 * to a currently unused target, then this is where you can perform 238 * those allocations. 239 * 240 * Return values: 0 on success, non-0 on failure 241 * 242 * Status: OPTIONAL 243 */ 244 int (* target_alloc)(struct scsi_target *); 245 246 /* 247 * Immediately prior to deallocating the target structure, and 248 * after all activity to attached scsi devices has ceased, the 249 * midlayer calls this point so that the driver may deallocate 250 * and terminate any references to the target. 251 * 252 * Status: OPTIONAL 253 */ 254 void (* target_destroy)(struct scsi_target *); 255 256 /* 257 * fill in this function to allow the queue depth of this host 258 * to be changeable (on a per device basis). returns either 259 * the current queue depth setting (may be different from what 260 * was passed in) or an error. An error should only be 261 * returned if the requested depth is legal but the driver was 262 * unable to set it. If the requested depth is illegal, the 263 * driver should set and return the closest legal queue depth. 264 * 265 */ 266 int (* change_queue_depth)(struct scsi_device *, int); 267 268 /* 269 * fill in this function to allow the changing of tag types 270 * (this also allows the enabling/disabling of tag command 271 * queueing). An error should only be returned if something 272 * went wrong in the driver while trying to set the tag type. 273 * If the driver doesn't support the requested tag type, then 274 * it should set the closest type it does support without 275 * returning an error. Returns the actual tag type set. 276 */ 277 int (* change_queue_type)(struct scsi_device *, int); 278 279 /* 280 * This function determines the bios parameters for a given 281 * harddisk. These tend to be numbers that are made up by 282 * the host adapter. Parameters: 283 * size, device, list (heads, sectors, cylinders) 284 * 285 * Status: OPTIONAL */ 286 int (* bios_param)(struct scsi_device *, struct block_device *, 287 sector_t, int []); 288 289 /* 290 * Can be used to export driver statistics and other infos to the 291 * world outside the kernel ie. userspace and it also provides an 292 * interface to feed the driver with information. 293 * 294 * Status: OBSOLETE 295 */ 296 int (*proc_info)(struct Scsi_Host *, char *, char **, off_t, int, int); 297 298 /* 299 * Name of proc directory 300 */ 301 char *proc_name; 302 303 /* 304 * Used to store the procfs directory if a driver implements the 305 * proc_info method. 306 */ 307 struct proc_dir_entry *proc_dir; 308 309 /* 310 * This determines if we will use a non-interrupt driven 311 * or an interrupt driven scheme, It is set to the maximum number 312 * of simultaneous commands a given host adapter will accept. 313 */ 314 int can_queue; 315 316 /* 317 * In many instances, especially where disconnect / reconnect are 318 * supported, our host also has an ID on the SCSI bus. If this is 319 * the case, then it must be reserved. Please set this_id to -1 if 320 * your setup is in single initiator mode, and the host lacks an 321 * ID. 322 */ 323 int this_id; 324 325 /* 326 * This determines the degree to which the host adapter is capable 327 * of scatter-gather. 328 */ 329 unsigned short sg_tablesize; 330 331 /* 332 * If the host adapter has limitations beside segment count 333 */ 334 unsigned short max_sectors; 335 336 /* 337 * dma scatter gather segment boundary limit. a segment crossing this 338 * boundary will be split in two. 339 */ 340 unsigned long dma_boundary; 341 342 /* 343 * This specifies "machine infinity" for host templates which don't 344 * limit the transfer size. Note this limit represents an absolute 345 * maximum, and may be over the transfer limits allowed for 346 * individual devices (e.g. 256 for SCSI-1) 347 */ 348 #define SCSI_DEFAULT_MAX_SECTORS 1024 349 350 /* 351 * True if this host adapter can make good use of linked commands. 352 * This will allow more than one command to be queued to a given 353 * unit on a given host. Set this to the maximum number of command 354 * blocks to be provided for each device. Set this to 1 for one 355 * command block per lun, 2 for two, etc. Do not set this to 0. 356 * You should make sure that the host adapter will do the right thing 357 * before you try setting this above 1. 358 */ 359 short cmd_per_lun; 360 361 /* 362 * present contains counter indicating how many boards of this 363 * type were found when we did the scan. 364 */ 365 unsigned char present; 366 367 /* 368 * true if this host adapter uses unchecked DMA onto an ISA bus. 369 */ 370 unsigned unchecked_isa_dma:1; 371 372 /* 373 * true if this host adapter can make good use of clustering. 374 * I originally thought that if the tablesize was large that it 375 * was a waste of CPU cycles to prepare a cluster list, but 376 * it works out that the Buslogic is faster if you use a smaller 377 * number of segments (i.e. use clustering). I guess it is 378 * inefficient. 379 */ 380 unsigned use_clustering:1; 381 382 /* 383 * True for emulated SCSI host adapters (e.g. ATAPI) 384 */ 385 unsigned emulated:1; 386 387 /* 388 * True if the low-level driver performs its own reset-settle delays. 389 */ 390 unsigned skip_settle_delay:1; 391 392 /* 393 * ordered write support 394 */ 395 unsigned ordered_flush:1; 396 unsigned ordered_tag:1; 397 398 /* 399 * Countdown for host blocking with no commands outstanding 400 */ 401 unsigned int max_host_blocked; 402 403 /* 404 * Default value for the blocking. If the queue is empty, 405 * host_blocked counts down in the request_fn until it restarts 406 * host operations as zero is reached. 407 * 408 * FIXME: This should probably be a value in the template 409 */ 410 #define SCSI_DEFAULT_HOST_BLOCKED 7 411 412 /* 413 * Pointer to the sysfs class properties for this host, NULL terminated. 414 */ 415 struct class_device_attribute **shost_attrs; 416 417 /* 418 * Pointer to the SCSI device properties for this host, NULL terminated. 419 */ 420 struct device_attribute **sdev_attrs; 421 422 /* 423 * List of hosts per template. 424 * 425 * This is only for use by scsi_module.c for legacy templates. 426 * For these access to it is synchronized implicitly by 427 * module_init/module_exit. 428 */ 429 struct list_head legacy_hosts; 430 }; 431 432 /* 433 * shost state: If you alter this, you also need to alter scsi_sysfs.c 434 * (for the ascii descriptions) and the state model enforcer: 435 * scsi_host_set_state() 436 */ 437 enum scsi_host_state { 438 SHOST_CREATED = 1, 439 SHOST_RUNNING, 440 SHOST_CANCEL, 441 SHOST_DEL, 442 SHOST_RECOVERY, 443 SHOST_CANCEL_RECOVERY, 444 SHOST_DEL_RECOVERY, 445 }; 446 447 struct Scsi_Host { 448 /* 449 * __devices is protected by the host_lock, but you should 450 * usually use scsi_device_lookup / shost_for_each_device 451 * to access it and don't care about locking yourself. 452 * In the rare case of beeing in irq context you can use 453 * their __ prefixed variants with the lock held. NEVER 454 * access this list directly from a driver. 455 */ 456 struct list_head __devices; 457 struct list_head __targets; 458 459 struct scsi_host_cmd_pool *cmd_pool; 460 spinlock_t free_list_lock; 461 struct list_head free_list; /* backup store of cmd structs */ 462 struct list_head starved_list; 463 464 spinlock_t default_lock; 465 spinlock_t *host_lock; 466 467 struct semaphore scan_mutex;/* serialize scanning activity */ 468 469 struct list_head eh_cmd_q; 470 struct task_struct * ehandler; /* Error recovery thread. */ 471 struct completion * eh_action; /* Wait for specific actions on the 472 host. */ 473 wait_queue_head_t host_wait; 474 struct scsi_host_template *hostt; 475 struct scsi_transport_template *transportt; 476 477 /* 478 * The following two fields are protected with host_lock; 479 * however, eh routines can safely access during eh processing 480 * without acquiring the lock. 481 */ 482 unsigned int host_busy; /* commands actually active on low-level */ 483 unsigned int host_failed; /* commands that failed. */ 484 485 unsigned short host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */ 486 int resetting; /* if set, it means that last_reset is a valid value */ 487 unsigned long last_reset; 488 489 /* 490 * These three parameters can be used to allow for wide scsi, 491 * and for host adapters that support multiple busses 492 * The first two should be set to 1 more than the actual max id 493 * or lun (i.e. 8 for normal systems). 494 */ 495 unsigned int max_id; 496 unsigned int max_lun; 497 unsigned int max_channel; 498 499 /* 500 * This is a unique identifier that must be assigned so that we 501 * have some way of identifying each detected host adapter properly 502 * and uniquely. For hosts that do not support more than one card 503 * in the system at one time, this does not need to be set. It is 504 * initialized to 0 in scsi_register. 505 */ 506 unsigned int unique_id; 507 508 /* 509 * The maximum length of SCSI commands that this host can accept. 510 * Probably 12 for most host adapters, but could be 16 for others. 511 * For drivers that don't set this field, a value of 12 is 512 * assumed. I am leaving this as a number rather than a bit 513 * because you never know what subsequent SCSI standards might do 514 * (i.e. could there be a 20 byte or a 24-byte command a few years 515 * down the road?). 516 */ 517 unsigned char max_cmd_len; 518 519 int this_id; 520 int can_queue; 521 short cmd_per_lun; 522 short unsigned int sg_tablesize; 523 short unsigned int max_sectors; 524 unsigned long dma_boundary; 525 /* 526 * Used to assign serial numbers to the cmds. 527 * Protected by the host lock. 528 */ 529 unsigned long cmd_serial_number, cmd_pid; 530 531 unsigned unchecked_isa_dma:1; 532 unsigned use_clustering:1; 533 unsigned use_blk_tcq:1; 534 535 /* 536 * Host has requested that no further requests come through for the 537 * time being. 538 */ 539 unsigned host_self_blocked:1; 540 541 /* 542 * Host uses correct SCSI ordering not PC ordering. The bit is 543 * set for the minority of drivers whose authors actually read 544 * the spec ;) 545 */ 546 unsigned reverse_ordering:1; 547 548 /* 549 * ordered write support 550 */ 551 unsigned ordered_flush:1; 552 unsigned ordered_tag:1; 553 554 /* 555 * Optional work queue to be utilized by the transport 556 */ 557 char work_q_name[KOBJ_NAME_LEN]; 558 struct workqueue_struct *work_q; 559 560 /* 561 * Host has rejected a command because it was busy. 562 */ 563 unsigned int host_blocked; 564 565 /* 566 * Value host_blocked counts down from 567 */ 568 unsigned int max_host_blocked; 569 570 /* legacy crap */ 571 unsigned long base; 572 unsigned long io_port; 573 unsigned char n_io_port; 574 unsigned char dma_channel; 575 unsigned int irq; 576 577 578 enum scsi_host_state shost_state; 579 580 /* ldm bits */ 581 struct device shost_gendev; 582 struct class_device shost_classdev; 583 584 /* 585 * List of hosts per template. 586 * 587 * This is only for use by scsi_module.c for legacy templates. 588 * For these access to it is synchronized implicitly by 589 * module_init/module_exit. 590 */ 591 struct list_head sht_legacy_list; 592 593 /* 594 * Points to the transport data (if any) which is allocated 595 * separately 596 */ 597 void *shost_data; 598 599 /* 600 * We should ensure that this is aligned, both for better performance 601 * and also because some compilers (m68k) don't automatically force 602 * alignment to a long boundary. 603 */ 604 unsigned long hostdata[0] /* Used for storage of host specific stuff */ 605 __attribute__ ((aligned (sizeof(unsigned long)))); 606 }; 607 608 #define class_to_shost(d) \ 609 container_of(d, struct Scsi_Host, shost_classdev) 610 611 #define shost_printk(prefix, shost, fmt, a...) \ 612 dev_printk(prefix, &(shost)->shost_gendev, fmt, ##a) 613 614 615 int scsi_is_host_device(const struct device *); 616 617 static inline struct Scsi_Host *dev_to_shost(struct device *dev) 618 { 619 while (!scsi_is_host_device(dev)) { 620 if (!dev->parent) 621 return NULL; 622 dev = dev->parent; 623 } 624 return container_of(dev, struct Scsi_Host, shost_gendev); 625 } 626 627 static inline int scsi_host_in_recovery(struct Scsi_Host *shost) 628 { 629 return shost->shost_state == SHOST_RECOVERY || 630 shost->shost_state == SHOST_CANCEL_RECOVERY || 631 shost->shost_state == SHOST_DEL_RECOVERY; 632 } 633 634 extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *); 635 extern void scsi_flush_work(struct Scsi_Host *); 636 637 extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int); 638 extern int __must_check scsi_add_host(struct Scsi_Host *, struct device *); 639 extern void scsi_scan_host(struct Scsi_Host *); 640 extern void scsi_rescan_device(struct device *); 641 extern void scsi_remove_host(struct Scsi_Host *); 642 extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *); 643 extern void scsi_host_put(struct Scsi_Host *t); 644 extern struct Scsi_Host *scsi_host_lookup(unsigned short); 645 extern const char *scsi_host_state_name(enum scsi_host_state); 646 647 extern u64 scsi_calculate_bounce_limit(struct Scsi_Host *); 648 649 static inline void scsi_assign_lock(struct Scsi_Host *shost, spinlock_t *lock) 650 { 651 shost->host_lock = lock; 652 } 653 654 static inline struct device *scsi_get_device(struct Scsi_Host *shost) 655 { 656 return shost->shost_gendev.parent; 657 } 658 659 /** 660 * scsi_host_scan_allowed - Is scanning of this host allowed 661 * @shost: Pointer to Scsi_Host. 662 **/ 663 static inline int scsi_host_scan_allowed(struct Scsi_Host *shost) 664 { 665 return shost->shost_state == SHOST_RUNNING; 666 } 667 668 extern void scsi_unblock_requests(struct Scsi_Host *); 669 extern void scsi_block_requests(struct Scsi_Host *); 670 671 struct class_container; 672 /* 673 * These two functions are used to allocate and free a pseudo device 674 * which will connect to the host adapter itself rather than any 675 * physical device. You must deallocate when you are done with the 676 * thing. This physical pseudo-device isn't real and won't be available 677 * from any high-level drivers. 678 */ 679 extern void scsi_free_host_dev(struct scsi_device *); 680 extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *); 681 682 /* legacy interfaces */ 683 extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int); 684 extern void scsi_unregister(struct Scsi_Host *); 685 extern int scsi_host_set_state(struct Scsi_Host *, enum scsi_host_state); 686 687 #endif /* _SCSI_SCSI_HOST_H */ 688