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 module; 11 struct scsi_cmnd; 12 struct scsi_device; 13 struct scsi_target; 14 struct Scsi_Host; 15 struct scsi_host_cmd_pool; 16 struct scsi_transport_template; 17 18 19 /* 20 * The various choices mean: 21 * NONE: Self evident. Host adapter is not capable of scatter-gather. 22 * ALL: Means that the host adapter module can do scatter-gather, 23 * and that there is no limit to the size of the table to which 24 * we scatter/gather data. 25 * Anything else: Indicates the maximum number of chains that can be 26 * used in one scatter-gather request. 27 */ 28 #define SG_NONE 0 29 #define SG_ALL 0xff 30 31 32 #define DISABLE_CLUSTERING 0 33 #define ENABLE_CLUSTERING 1 34 35 enum scsi_eh_timer_return { 36 EH_NOT_HANDLED, 37 EH_HANDLED, 38 EH_RESET_TIMER, 39 }; 40 41 42 struct scsi_host_template { 43 struct module *module; 44 const char *name; 45 46 /* 47 * Used to initialize old-style drivers. For new-style drivers 48 * just perform all work in your module initialization function. 49 * 50 * Status: OBSOLETE 51 */ 52 int (* detect)(struct scsi_host_template *); 53 54 /* 55 * Used as unload callback for hosts with old-style drivers. 56 * 57 * Status: OBSOLETE 58 */ 59 int (* release)(struct Scsi_Host *); 60 61 /* 62 * The info function will return whatever useful information the 63 * developer sees fit. If not provided, then the name field will 64 * be used instead. 65 * 66 * Status: OPTIONAL 67 */ 68 const char *(* info)(struct Scsi_Host *); 69 70 /* 71 * Ioctl interface 72 * 73 * Status: OPTIONAL 74 */ 75 int (* ioctl)(struct scsi_device *dev, int cmd, void __user *arg); 76 77 78 #ifdef CONFIG_COMPAT 79 /* 80 * Compat handler. Handle 32bit ABI. 81 * When unknown ioctl is passed return -ENOIOCTLCMD. 82 * 83 * Status: OPTIONAL 84 */ 85 int (* compat_ioctl)(struct scsi_device *dev, int cmd, void __user *arg); 86 #endif 87 88 /* 89 * The queuecommand function is used to queue up a scsi 90 * command block to the LLDD. When the driver finished 91 * processing the command the done callback is invoked. 92 * 93 * If queuecommand returns 0, then the HBA has accepted the 94 * command. The done() function must be called on the command 95 * when the driver has finished with it. (you may call done on the 96 * command before queuecommand returns, but in this case you 97 * *must* return 0 from queuecommand). 98 * 99 * Queuecommand may also reject the command, in which case it may 100 * not touch the command and must not call done() for it. 101 * 102 * There are two possible rejection returns: 103 * 104 * SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but 105 * allow commands to other devices serviced by this host. 106 * 107 * SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this 108 * host temporarily. 109 * 110 * For compatibility, any other non-zero return is treated the 111 * same as SCSI_MLQUEUE_HOST_BUSY. 112 * 113 * NOTE: "temporarily" means either until the next command for# 114 * this device/host completes, or a period of time determined by 115 * I/O pressure in the system if there are no other outstanding 116 * commands. 117 * 118 * STATUS: REQUIRED 119 */ 120 int (* queuecommand)(struct scsi_cmnd *, 121 void (*done)(struct scsi_cmnd *)); 122 123 /* 124 * This is an error handling strategy routine. You don't need to 125 * define one of these if you don't want to - there is a default 126 * routine that is present that should work in most cases. For those 127 * driver authors that have the inclination and ability to write their 128 * own strategy routine, this is where it is specified. Note - the 129 * strategy routine is *ALWAYS* run in the context of the kernel eh 130 * thread. Thus you are guaranteed to *NOT* be in an interrupt 131 * handler when you execute this, and you are also guaranteed to 132 * *NOT* have any other commands being queued while you are in the 133 * strategy routine. When you return from this function, operations 134 * return to normal. 135 * 136 * See scsi_error.c scsi_unjam_host for additional comments about 137 * what this function should and should not be attempting to do. 138 * 139 * Status: REQUIRED (at least one of them) 140 */ 141 int (* eh_strategy_handler)(struct Scsi_Host *); 142 int (* eh_abort_handler)(struct scsi_cmnd *); 143 int (* eh_device_reset_handler)(struct scsi_cmnd *); 144 int (* eh_bus_reset_handler)(struct scsi_cmnd *); 145 int (* eh_host_reset_handler)(struct scsi_cmnd *); 146 147 /* 148 * This is an optional routine to notify the host that the scsi 149 * timer just fired. The returns tell the timer routine what to 150 * do about this: 151 * 152 * EH_HANDLED: I fixed the error, please complete the command 153 * EH_RESET_TIMER: I need more time, reset the timer and 154 * begin counting again 155 * EH_NOT_HANDLED Begin normal error recovery 156 * 157 * Status: OPTIONAL 158 */ 159 enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *); 160 161 /* 162 * Before the mid layer attempts to scan for a new device where none 163 * currently exists, it will call this entry in your driver. Should 164 * your driver need to allocate any structs or perform any other init 165 * items in order to send commands to a currently unused target/lun 166 * combo, then this is where you can perform those allocations. This 167 * is specifically so that drivers won't have to perform any kind of 168 * "is this a new device" checks in their queuecommand routine, 169 * thereby making the hot path a bit quicker. 170 * 171 * Return values: 0 on success, non-0 on failure 172 * 173 * Deallocation: If we didn't find any devices at this ID, you will 174 * get an immediate call to slave_destroy(). If we find something 175 * here then you will get a call to slave_configure(), then the 176 * device will be used for however long it is kept around, then when 177 * the device is removed from the system (or * possibly at reboot 178 * time), you will then get a call to slave_destroy(). This is 179 * assuming you implement slave_configure and slave_destroy. 180 * However, if you allocate memory and hang it off the device struct, 181 * then you must implement the slave_destroy() routine at a minimum 182 * in order to avoid leaking memory 183 * each time a device is tore down. 184 * 185 * Status: OPTIONAL 186 */ 187 int (* slave_alloc)(struct scsi_device *); 188 189 /* 190 * Once the device has responded to an INQUIRY and we know the 191 * device is online, we call into the low level driver with the 192 * struct scsi_device *. If the low level device driver implements 193 * this function, it *must* perform the task of setting the queue 194 * depth on the device. All other tasks are optional and depend 195 * on what the driver supports and various implementation details. 196 * 197 * Things currently recommended to be handled at this time include: 198 * 199 * 1. Setting the device queue depth. Proper setting of this is 200 * described in the comments for scsi_adjust_queue_depth. 201 * 2. Determining if the device supports the various synchronous 202 * negotiation protocols. The device struct will already have 203 * responded to INQUIRY and the results of the standard items 204 * will have been shoved into the various device flag bits, eg. 205 * device->sdtr will be true if the device supports SDTR messages. 206 * 3. Allocating command structs that the device will need. 207 * 4. Setting the default timeout on this device (if needed). 208 * 5. Anything else the low level driver might want to do on a device 209 * specific setup basis... 210 * 6. Return 0 on success, non-0 on error. The device will be marked 211 * as offline on error so that no access will occur. If you return 212 * non-0, your slave_destroy routine will never get called for this 213 * device, so don't leave any loose memory hanging around, clean 214 * up after yourself before returning non-0 215 * 216 * Status: OPTIONAL 217 */ 218 int (* slave_configure)(struct scsi_device *); 219 220 /* 221 * Immediately prior to deallocating the device and after all activity 222 * has ceased the mid layer calls this point so that the low level 223 * driver may completely detach itself from the scsi device and vice 224 * versa. The low level driver is responsible for freeing any memory 225 * it allocated in the slave_alloc or slave_configure calls. 226 * 227 * Status: OPTIONAL 228 */ 229 void (* slave_destroy)(struct scsi_device *); 230 231 /* 232 * Before the mid layer attempts to scan for a new device attached 233 * to a target where no target currently exists, it will call this 234 * entry in your driver. Should your driver need to allocate any 235 * structs or perform any other init items in order to send commands 236 * to a currently unused target, then this is where you can perform 237 * those allocations. 238 * 239 * Return values: 0 on success, non-0 on failure 240 * 241 * Status: OPTIONAL 242 */ 243 int (* target_alloc)(struct scsi_target *); 244 245 /* 246 * Immediately prior to deallocating the target structure, and 247 * after all activity to attached scsi devices has ceased, the 248 * midlayer calls this point so that the driver may deallocate 249 * and terminate any references to the target. 250 * 251 * Status: OPTIONAL 252 */ 253 void (* target_destroy)(struct scsi_target *); 254 255 /* 256 * fill in this function to allow the queue depth of this host 257 * to be changeable (on a per device basis). returns either 258 * the current queue depth setting (may be different from what 259 * was passed in) or an error. An error should only be 260 * returned if the requested depth is legal but the driver was 261 * unable to set it. If the requested depth is illegal, the 262 * driver should set and return the closest legal queue depth. 263 * 264 */ 265 int (* change_queue_depth)(struct scsi_device *, int); 266 267 /* 268 * fill in this function to allow the changing of tag types 269 * (this also allows the enabling/disabling of tag command 270 * queueing). An error should only be returned if something 271 * went wrong in the driver while trying to set the tag type. 272 * If the driver doesn't support the requested tag type, then 273 * it should set the closest type it does support without 274 * returning an error. Returns the actual tag type set. 275 */ 276 int (* change_queue_type)(struct scsi_device *, int); 277 278 /* 279 * This function determines the bios parameters for a given 280 * harddisk. These tend to be numbers that are made up by 281 * the host adapter. Parameters: 282 * size, device, list (heads, sectors, cylinders) 283 * 284 * Status: OPTIONAL */ 285 int (* bios_param)(struct scsi_device *, struct block_device *, 286 sector_t, int []); 287 288 /* 289 * Can be used to export driver statistics and other infos to the 290 * world outside the kernel ie. userspace and it also provides an 291 * interface to feed the driver with information. 292 * 293 * Status: OBSOLETE 294 */ 295 int (*proc_info)(struct Scsi_Host *, char *, char **, off_t, int, int); 296 297 /* 298 * Name of proc directory 299 */ 300 char *proc_name; 301 302 /* 303 * Used to store the procfs directory if a driver implements the 304 * proc_info method. 305 */ 306 struct proc_dir_entry *proc_dir; 307 308 /* 309 * This determines if we will use a non-interrupt driven 310 * or an interrupt driven scheme, It is set to the maximum number 311 * of simultaneous commands a given host adapter will accept. 312 */ 313 int can_queue; 314 315 /* 316 * In many instances, especially where disconnect / reconnect are 317 * supported, our host also has an ID on the SCSI bus. If this is 318 * the case, then it must be reserved. Please set this_id to -1 if 319 * your setup is in single initiator mode, and the host lacks an 320 * ID. 321 */ 322 int this_id; 323 324 /* 325 * This determines the degree to which the host adapter is capable 326 * of scatter-gather. 327 */ 328 unsigned short sg_tablesize; 329 330 /* 331 * If the host adapter has limitations beside segment count 332 */ 333 unsigned short max_sectors; 334 335 /* 336 * dma scatter gather segment boundary limit. a segment crossing this 337 * boundary will be split in two. 338 */ 339 unsigned long dma_boundary; 340 341 /* 342 * This specifies "machine infinity" for host templates which don't 343 * limit the transfer size. Note this limit represents an absolute 344 * maximum, and may be over the transfer limits allowed for 345 * individual devices (e.g. 256 for SCSI-1) 346 */ 347 #define SCSI_DEFAULT_MAX_SECTORS 1024 348 349 /* 350 * True if this host adapter can make good use of linked commands. 351 * This will allow more than one command to be queued to a given 352 * unit on a given host. Set this to the maximum number of command 353 * blocks to be provided for each device. Set this to 1 for one 354 * command block per lun, 2 for two, etc. Do not set this to 0. 355 * You should make sure that the host adapter will do the right thing 356 * before you try setting this above 1. 357 */ 358 short cmd_per_lun; 359 360 /* 361 * present contains counter indicating how many boards of this 362 * type were found when we did the scan. 363 */ 364 unsigned char present; 365 366 /* 367 * true if this host adapter uses unchecked DMA onto an ISA bus. 368 */ 369 unsigned unchecked_isa_dma:1; 370 371 /* 372 * true if this host adapter can make good use of clustering. 373 * I originally thought that if the tablesize was large that it 374 * was a waste of CPU cycles to prepare a cluster list, but 375 * it works out that the Buslogic is faster if you use a smaller 376 * number of segments (i.e. use clustering). I guess it is 377 * inefficient. 378 */ 379 unsigned use_clustering:1; 380 381 /* 382 * True for emulated SCSI host adapters (e.g. ATAPI) 383 */ 384 unsigned emulated:1; 385 386 /* 387 * True if the low-level driver performs its own reset-settle delays. 388 */ 389 unsigned skip_settle_delay:1; 390 391 /* 392 * ordered write support 393 */ 394 unsigned ordered_flush:1; 395 unsigned ordered_tag:1; 396 397 /* 398 * Countdown for host blocking with no commands outstanding 399 */ 400 unsigned int max_host_blocked; 401 402 /* 403 * Default value for the blocking. If the queue is empty, 404 * host_blocked counts down in the request_fn until it restarts 405 * host operations as zero is reached. 406 * 407 * FIXME: This should probably be a value in the template 408 */ 409 #define SCSI_DEFAULT_HOST_BLOCKED 7 410 411 /* 412 * Pointer to the sysfs class properties for this host, NULL terminated. 413 */ 414 struct class_device_attribute **shost_attrs; 415 416 /* 417 * Pointer to the SCSI device properties for this host, NULL terminated. 418 */ 419 struct device_attribute **sdev_attrs; 420 421 /* 422 * List of hosts per template. 423 * 424 * This is only for use by scsi_module.c for legacy templates. 425 * For these access to it is synchronized implicitly by 426 * module_init/module_exit. 427 */ 428 struct list_head legacy_hosts; 429 }; 430 431 /* 432 * shost states 433 */ 434 enum { 435 SHOST_ADD, 436 SHOST_DEL, 437 SHOST_CANCEL, 438 SHOST_RECOVERY, 439 }; 440 441 struct Scsi_Host { 442 /* 443 * __devices is protected by the host_lock, but you should 444 * usually use scsi_device_lookup / shost_for_each_device 445 * to access it and don't care about locking yourself. 446 * In the rare case of beeing in irq context you can use 447 * their __ prefixed variants with the lock held. NEVER 448 * access this list directly from a driver. 449 */ 450 struct list_head __devices; 451 struct list_head __targets; 452 453 struct scsi_host_cmd_pool *cmd_pool; 454 spinlock_t free_list_lock; 455 struct list_head free_list; /* backup store of cmd structs */ 456 struct list_head starved_list; 457 458 spinlock_t default_lock; 459 spinlock_t *host_lock; 460 461 struct semaphore scan_mutex;/* serialize scanning activity */ 462 463 struct list_head eh_cmd_q; 464 struct task_struct * ehandler; /* Error recovery thread. */ 465 struct semaphore * eh_wait; /* The error recovery thread waits 466 on this. */ 467 struct completion * eh_notify; /* wait for eh to begin or end */ 468 struct semaphore * eh_action; /* Wait for specific actions on the 469 host. */ 470 unsigned int eh_active:1; /* Indicates the eh thread is awake and active if 471 this is true. */ 472 unsigned int eh_kill:1; /* set when killing the eh thread */ 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 unsigned long 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 int scsi_is_host_device(const struct device *); 612 613 static inline struct Scsi_Host *dev_to_shost(struct device *dev) 614 { 615 while (!scsi_is_host_device(dev)) { 616 if (!dev->parent) 617 return NULL; 618 dev = dev->parent; 619 } 620 return container_of(dev, struct Scsi_Host, shost_gendev); 621 } 622 623 extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *); 624 extern void scsi_flush_work(struct Scsi_Host *); 625 626 extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int); 627 extern int __must_check scsi_add_host(struct Scsi_Host *, struct device *); 628 extern void scsi_scan_host(struct Scsi_Host *); 629 extern void scsi_scan_single_target(struct Scsi_Host *, unsigned int, 630 unsigned int); 631 extern void scsi_rescan_device(struct device *); 632 extern void scsi_remove_host(struct Scsi_Host *); 633 extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *); 634 extern void scsi_host_put(struct Scsi_Host *t); 635 extern struct Scsi_Host *scsi_host_lookup(unsigned short); 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 void scsi_set_device(struct Scsi_Host *shost, 645 struct device *dev) 646 { 647 shost->shost_gendev.parent = dev; 648 } 649 650 static inline struct device *scsi_get_device(struct Scsi_Host *shost) 651 { 652 return shost->shost_gendev.parent; 653 } 654 655 extern void scsi_unblock_requests(struct Scsi_Host *); 656 extern void scsi_block_requests(struct Scsi_Host *); 657 658 struct class_container; 659 /* 660 * These two functions are used to allocate and free a pseudo device 661 * which will connect to the host adapter itself rather than any 662 * physical device. You must deallocate when you are done with the 663 * thing. This physical pseudo-device isn't real and won't be available 664 * from any high-level drivers. 665 */ 666 extern void scsi_free_host_dev(struct scsi_device *); 667 extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *); 668 669 /* legacy interfaces */ 670 extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int); 671 extern void scsi_unregister(struct Scsi_Host *); 672 673 #endif /* _SCSI_SCSI_HOST_H */ 674