1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _SCSI_SCSI_HOST_H
3 #define _SCSI_SCSI_HOST_H
5 #include <linux/device.h>
6 #include <linux/list.h>
7 #include <linux/types.h>
8 #include <linux/workqueue.h>
9 #include <linux/mutex.h>
10 #include <linux/seq_file.h>
11 #include <linux/blk-mq.h>
12 #include <scsi/scsi.h>
20 struct scsi_host_cmd_pool
;
23 struct scsi_host_cmd_pool
;
24 struct scsi_transport_template
;
25 struct blk_queue_tags
;
29 * The various choices mean:
30 * NONE: Self evident. Host adapter is not capable of scatter-gather.
31 * ALL: Means that the host adapter module can do scatter-gather,
32 * and that there is no limit to the size of the table to which
33 * we scatter/gather data. The value we set here is the maximum
34 * single element sglist. To use chained sglists, the adapter
35 * has to set a value beyond ALL (and correctly use the chain
37 * Anything else: Indicates the maximum number of chains that can be
38 * used in one scatter-gather request.
41 #define SG_ALL SG_CHUNK_SIZE
43 #define MODE_UNKNOWN 0x00
44 #define MODE_INITIATOR 0x01
45 #define MODE_TARGET 0x02
47 #define DISABLE_CLUSTERING 0
48 #define ENABLE_CLUSTERING 1
50 struct scsi_host_template
{
51 struct module
*module
;
55 * The info function will return whatever useful information the
56 * developer sees fit. If not provided, then the name field will
61 const char *(* info
)(struct Scsi_Host
*);
68 int (* ioctl
)(struct scsi_device
*dev
, int cmd
, void __user
*arg
);
73 * Compat handler. Handle 32bit ABI.
74 * When unknown ioctl is passed return -ENOIOCTLCMD.
78 int (* compat_ioctl
)(struct scsi_device
*dev
, int cmd
, void __user
*arg
);
82 * The queuecommand function is used to queue up a scsi
83 * command block to the LLDD. When the driver finished
84 * processing the command the done callback is invoked.
86 * If queuecommand returns 0, then the HBA has accepted the
87 * command. The done() function must be called on the command
88 * when the driver has finished with it. (you may call done on the
89 * command before queuecommand returns, but in this case you
90 * *must* return 0 from queuecommand).
92 * Queuecommand may also reject the command, in which case it may
93 * not touch the command and must not call done() for it.
95 * There are two possible rejection returns:
97 * SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but
98 * allow commands to other devices serviced by this host.
100 * SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this
103 * For compatibility, any other non-zero return is treated the
104 * same as SCSI_MLQUEUE_HOST_BUSY.
106 * NOTE: "temporarily" means either until the next command for#
107 * this device/host completes, or a period of time determined by
108 * I/O pressure in the system if there are no other outstanding
113 int (* queuecommand
)(struct Scsi_Host
*, struct scsi_cmnd
*);
116 * This is an error handling strategy routine. You don't need to
117 * define one of these if you don't want to - there is a default
118 * routine that is present that should work in most cases. For those
119 * driver authors that have the inclination and ability to write their
120 * own strategy routine, this is where it is specified. Note - the
121 * strategy routine is *ALWAYS* run in the context of the kernel eh
122 * thread. Thus you are guaranteed to *NOT* be in an interrupt
123 * handler when you execute this, and you are also guaranteed to
124 * *NOT* have any other commands being queued while you are in the
125 * strategy routine. When you return from this function, operations
128 * See scsi_error.c scsi_unjam_host for additional comments about
129 * what this function should and should not be attempting to do.
131 * Status: REQUIRED (at least one of them)
133 int (* eh_abort_handler
)(struct scsi_cmnd
*);
134 int (* eh_device_reset_handler
)(struct scsi_cmnd
*);
135 int (* eh_target_reset_handler
)(struct scsi_cmnd
*);
136 int (* eh_bus_reset_handler
)(struct scsi_cmnd
*);
137 int (* eh_host_reset_handler
)(struct scsi_cmnd
*);
140 * Before the mid layer attempts to scan for a new device where none
141 * currently exists, it will call this entry in your driver. Should
142 * your driver need to allocate any structs or perform any other init
143 * items in order to send commands to a currently unused target/lun
144 * combo, then this is where you can perform those allocations. This
145 * is specifically so that drivers won't have to perform any kind of
146 * "is this a new device" checks in their queuecommand routine,
147 * thereby making the hot path a bit quicker.
149 * Return values: 0 on success, non-0 on failure
151 * Deallocation: If we didn't find any devices at this ID, you will
152 * get an immediate call to slave_destroy(). If we find something
153 * here then you will get a call to slave_configure(), then the
154 * device will be used for however long it is kept around, then when
155 * the device is removed from the system (or * possibly at reboot
156 * time), you will then get a call to slave_destroy(). This is
157 * assuming you implement slave_configure and slave_destroy.
158 * However, if you allocate memory and hang it off the device struct,
159 * then you must implement the slave_destroy() routine at a minimum
160 * in order to avoid leaking memory
161 * each time a device is tore down.
165 int (* slave_alloc
)(struct scsi_device
*);
168 * Once the device has responded to an INQUIRY and we know the
169 * device is online, we call into the low level driver with the
170 * struct scsi_device *. If the low level device driver implements
171 * this function, it *must* perform the task of setting the queue
172 * depth on the device. All other tasks are optional and depend
173 * on what the driver supports and various implementation details.
175 * Things currently recommended to be handled at this time include:
177 * 1. Setting the device queue depth. Proper setting of this is
178 * described in the comments for scsi_change_queue_depth.
179 * 2. Determining if the device supports the various synchronous
180 * negotiation protocols. The device struct will already have
181 * responded to INQUIRY and the results of the standard items
182 * will have been shoved into the various device flag bits, eg.
183 * device->sdtr will be true if the device supports SDTR messages.
184 * 3. Allocating command structs that the device will need.
185 * 4. Setting the default timeout on this device (if needed).
186 * 5. Anything else the low level driver might want to do on a device
187 * specific setup basis...
188 * 6. Return 0 on success, non-0 on error. The device will be marked
189 * as offline on error so that no access will occur. If you return
190 * non-0, your slave_destroy routine will never get called for this
191 * device, so don't leave any loose memory hanging around, clean
192 * up after yourself before returning non-0
196 int (* slave_configure
)(struct scsi_device
*);
199 * Immediately prior to deallocating the device and after all activity
200 * has ceased the mid layer calls this point so that the low level
201 * driver may completely detach itself from the scsi device and vice
202 * versa. The low level driver is responsible for freeing any memory
203 * it allocated in the slave_alloc or slave_configure calls.
207 void (* slave_destroy
)(struct scsi_device
*);
210 * Before the mid layer attempts to scan for a new device attached
211 * to a target where no target currently exists, it will call this
212 * entry in your driver. Should your driver need to allocate any
213 * structs or perform any other init items in order to send commands
214 * to a currently unused target, then this is where you can perform
217 * Return values: 0 on success, non-0 on failure
221 int (* target_alloc
)(struct scsi_target
*);
224 * Immediately prior to deallocating the target structure, and
225 * after all activity to attached scsi devices has ceased, the
226 * midlayer calls this point so that the driver may deallocate
227 * and terminate any references to the target.
231 void (* target_destroy
)(struct scsi_target
*);
234 * If a host has the ability to discover targets on its own instead
235 * of scanning the entire bus, it can fill in this function and
236 * call scsi_scan_host(). This function will be called periodically
237 * until it returns 1 with the scsi_host and the elapsed time of
238 * the scan in jiffies.
242 int (* scan_finished
)(struct Scsi_Host
*, unsigned long);
245 * If the host wants to be called before the scan starts, but
246 * after the midlayer has set up ready for the scan, it can fill
251 void (* scan_start
)(struct Scsi_Host
*);
254 * Fill in this function to allow the queue depth of this host
255 * to be changeable (on a per device basis). Returns either
256 * the current queue depth setting (may be different from what
257 * was passed in) or an error. An error should only be
258 * returned if the requested depth is legal but the driver was
259 * unable to set it. If the requested depth is illegal, the
260 * driver should set and return the closest legal queue depth.
264 int (* change_queue_depth
)(struct scsi_device
*, int);
267 * This functions lets the driver expose the queue mapping
268 * to the block layer.
272 int (* map_queues
)(struct Scsi_Host
*shost
);
275 * This function determines the BIOS parameters for a given
276 * harddisk. These tend to be numbers that are made up by
277 * the host adapter. Parameters:
278 * size, device, list (heads, sectors, cylinders)
282 int (* bios_param
)(struct scsi_device
*, struct block_device
*,
286 * This function is called when one or more partitions on the
287 * device reach beyond the end of the device.
291 void (*unlock_native_capacity
)(struct scsi_device
*);
294 * Can be used to export driver statistics and other infos to the
295 * world outside the kernel ie. userspace and it also provides an
296 * interface to feed the driver with information.
300 int (*show_info
)(struct seq_file
*, struct Scsi_Host
*);
301 int (*write_info
)(struct Scsi_Host
*, char *, int);
304 * This is an optional routine that allows the transport to become
305 * involved when a scsi io timer fires. The return value tells the
306 * timer routine how to finish the io timeout handling:
307 * EH_HANDLED: I fixed the error, please complete the command
308 * EH_RESET_TIMER: I need more time, reset the timer and
309 * begin counting again
310 * EH_NOT_HANDLED Begin normal error recovery
314 enum blk_eh_timer_return (*eh_timed_out
)(struct scsi_cmnd
*);
316 /* This is an optional routine that allows transport to initiate
317 * LLD adapter or firmware reset using sysfs attribute.
319 * Return values: 0 on success, -ve value on failure.
324 int (*host_reset
)(struct Scsi_Host
*shost
, int reset_type
);
325 #define SCSI_ADAPTER_RESET 1
326 #define SCSI_FIRMWARE_RESET 2
330 * Name of proc directory
332 const char *proc_name
;
335 * Used to store the procfs directory if a driver implements the
338 struct proc_dir_entry
*proc_dir
;
341 * This determines if we will use a non-interrupt driven
342 * or an interrupt driven scheme. It is set to the maximum number
343 * of simultaneous commands a given host adapter will accept.
348 * In many instances, especially where disconnect / reconnect are
349 * supported, our host also has an ID on the SCSI bus. If this is
350 * the case, then it must be reserved. Please set this_id to -1 if
351 * your setup is in single initiator mode, and the host lacks an
357 * This determines the degree to which the host adapter is capable
360 unsigned short sg_tablesize
;
361 unsigned short sg_prot_tablesize
;
364 * Set this if the host adapter has limitations beside segment count.
366 unsigned int max_sectors
;
369 * DMA scatter gather segment boundary limit. A segment crossing this
370 * boundary will be split in two.
372 unsigned long dma_boundary
;
375 * This specifies "machine infinity" for host templates which don't
376 * limit the transfer size. Note this limit represents an absolute
377 * maximum, and may be over the transfer limits allowed for
378 * individual devices (e.g. 256 for SCSI-1).
380 #define SCSI_DEFAULT_MAX_SECTORS 1024
383 * True if this host adapter can make good use of linked commands.
384 * This will allow more than one command to be queued to a given
385 * unit on a given host. Set this to the maximum number of command
386 * blocks to be provided for each device. Set this to 1 for one
387 * command block per lun, 2 for two, etc. Do not set this to 0.
388 * You should make sure that the host adapter will do the right thing
389 * before you try setting this above 1.
394 * present contains counter indicating how many boards of this
395 * type were found when we did the scan.
397 unsigned char present
;
399 /* If use block layer to manage tags, this is tag allocation policy */
400 int tag_alloc_policy
;
403 * Track QUEUE_FULL events and reduce queue depth on demand.
405 unsigned track_queue_depth
:1;
408 * This specifies the mode that a LLD supports.
410 unsigned supported_mode
:2;
413 * True if this host adapter uses unchecked DMA onto an ISA bus.
415 unsigned unchecked_isa_dma
:1;
418 * True if this host adapter can make good use of clustering.
419 * I originally thought that if the tablesize was large that it
420 * was a waste of CPU cycles to prepare a cluster list, but
421 * it works out that the Buslogic is faster if you use a smaller
422 * number of segments (i.e. use clustering). I guess it is
425 unsigned use_clustering
:1;
428 * True for emulated SCSI host adapters (e.g. ATAPI).
433 * True if the low-level driver performs its own reset-settle delays.
435 unsigned skip_settle_delay
:1;
437 /* True if the controller does not support WRITE SAME */
438 unsigned no_write_same
:1;
440 /* True if the low-level driver supports blk-mq only */
441 unsigned force_blk_mq
:1;
444 * Countdown for host blocking with no commands outstanding.
446 unsigned int max_host_blocked
;
449 * Default value for the blocking. If the queue is empty,
450 * host_blocked counts down in the request_fn until it restarts
451 * host operations as zero is reached.
453 * FIXME: This should probably be a value in the template
455 #define SCSI_DEFAULT_HOST_BLOCKED 7
458 * Pointer to the sysfs class properties for this host, NULL terminated.
460 struct device_attribute
**shost_attrs
;
463 * Pointer to the SCSI device properties for this host, NULL terminated.
465 struct device_attribute
**sdev_attrs
;
468 * Pointer to the SCSI device attribute groups for this host,
471 const struct attribute_group
**sdev_groups
;
474 * Vendor Identifier associated with the host
476 * Note: When specifying vendor_id, be sure to read the
477 * Vendor Type and ID formatting requirements specified in
483 * Additional per-command data allocated for the driver.
485 unsigned int cmd_size
;
486 struct scsi_host_cmd_pool
*cmd_pool
;
490 * Temporary #define for host lock push down. Can be removed when all
491 * drivers have been updated to take advantage of unlocked
495 #define DEF_SCSI_QCMD(func_name) \
496 int func_name(struct Scsi_Host *shost, struct scsi_cmnd *cmd) \
498 unsigned long irq_flags; \
500 spin_lock_irqsave(shost->host_lock, irq_flags); \
501 scsi_cmd_get_serial(shost, cmd); \
502 rc = func_name##_lck (cmd, cmd->scsi_done); \
503 spin_unlock_irqrestore(shost->host_lock, irq_flags); \
509 * shost state: If you alter this, you also need to alter scsi_sysfs.c
510 * (for the ascii descriptions) and the state model enforcer:
511 * scsi_host_set_state()
513 enum scsi_host_state
{
519 SHOST_CANCEL_RECOVERY
,
525 * __devices is protected by the host_lock, but you should
526 * usually use scsi_device_lookup / shost_for_each_device
527 * to access it and don't care about locking yourself.
528 * In the rare case of being in irq context you can use
529 * their __ prefixed variants with the lock held. NEVER
530 * access this list directly from a driver.
532 struct list_head __devices
;
533 struct list_head __targets
;
535 struct list_head starved_list
;
537 spinlock_t default_lock
;
538 spinlock_t
*host_lock
;
540 struct mutex scan_mutex
;/* serialize scanning activity */
542 struct list_head eh_cmd_q
;
543 struct task_struct
* ehandler
; /* Error recovery thread. */
544 struct completion
* eh_action
; /* Wait for specific actions on the
546 wait_queue_head_t host_wait
;
547 struct scsi_host_template
*hostt
;
548 struct scsi_transport_template
*transportt
;
551 * Area to keep a shared tag map (if needed, will be
555 struct blk_queue_tag
*bqt
;
556 struct blk_mq_tag_set tag_set
;
559 atomic_t host_busy
; /* commands actually active on low-level */
560 atomic_t host_blocked
;
562 unsigned int host_failed
; /* commands that failed.
563 protected by host_lock */
564 unsigned int host_eh_scheduled
; /* EH scheduled without command */
566 unsigned int host_no
; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
568 /* next two fields are used to bound the time spent in error handling */
570 unsigned long last_reset
;
574 * These three parameters can be used to allow for wide scsi,
575 * and for host adapters that support multiple busses
576 * The last two should be set to 1 more than the actual max id
577 * or lun (e.g. 8 for SCSI parallel systems).
579 unsigned int max_channel
;
584 * This is a unique identifier that must be assigned so that we
585 * have some way of identifying each detected host adapter properly
586 * and uniquely. For hosts that do not support more than one card
587 * in the system at one time, this does not need to be set. It is
588 * initialized to 0 in scsi_register.
590 unsigned int unique_id
;
593 * The maximum length of SCSI commands that this host can accept.
594 * Probably 12 for most host adapters, but could be 16 for others.
595 * or 260 if the driver supports variable length cdbs.
596 * For drivers that don't set this field, a value of 12 is
599 unsigned short max_cmd_len
;
604 short unsigned int sg_tablesize
;
605 short unsigned int sg_prot_tablesize
;
606 unsigned int max_sectors
;
607 unsigned long dma_boundary
;
609 * In scsi-mq mode, the number of hardware queues supported by the LLD.
611 * Note: it is assumed that each hardware queue has a queue depth of
612 * can_queue. In other words, the total queue depth per host
613 * is nr_hw_queues * can_queue.
615 unsigned nr_hw_queues
;
617 * Used to assign serial numbers to the cmds.
618 * Protected by the host lock.
620 unsigned long cmd_serial_number
;
622 unsigned active_mode
:2;
623 unsigned unchecked_isa_dma
:1;
624 unsigned use_clustering
:1;
627 * Host has requested that no further requests come through for the
630 unsigned host_self_blocked
:1;
633 * Host uses correct SCSI ordering not PC ordering. The bit is
634 * set for the minority of drivers whose authors actually read
637 unsigned reverse_ordering
:1;
639 /* Task mgmt function in progress */
640 unsigned tmf_in_progress
:1;
642 /* Asynchronous scan in progress */
643 unsigned async_scan
:1;
645 /* Don't resume host in EH */
646 unsigned eh_noresume
:1;
648 /* The controller does not support WRITE SAME */
649 unsigned no_write_same
:1;
651 unsigned use_blk_mq
:1;
652 unsigned use_cmd_list
:1;
654 /* Host responded with short (<36 bytes) INQUIRY result */
655 unsigned short_inquiry
:1;
658 * Optional work queue to be utilized by the transport
660 char work_q_name
[20];
661 struct workqueue_struct
*work_q
;
664 * Task management function work queue
666 struct workqueue_struct
*tmf_work_q
;
668 /* The transport requires the LUN bits NOT to be stored in CDB[1] */
669 unsigned no_scsi2_lun_in_cdb
:1;
672 * Value host_blocked counts down from
674 unsigned int max_host_blocked
;
676 /* Protection Information */
677 unsigned int prot_capabilities
;
678 unsigned char prot_guard_type
;
682 unsigned long io_port
;
683 unsigned char n_io_port
;
684 unsigned char dma_channel
;
688 enum scsi_host_state shost_state
;
691 struct device shost_gendev
, shost_dev
;
694 * Points to the transport data (if any) which is allocated
700 * Points to the physical bus device we'd use to do DMA
701 * Needed just in case we have virtual hosts.
703 struct device
*dma_dev
;
706 * We should ensure that this is aligned, both for better performance
707 * and also because some compilers (m68k) don't automatically force
708 * alignment to a long boundary.
710 unsigned long hostdata
[0] /* Used for storage of host specific stuff */
711 __attribute__ ((aligned (sizeof(unsigned long))));
714 #define class_to_shost(d) \
715 container_of(d, struct Scsi_Host, shost_dev)
717 #define shost_printk(prefix, shost, fmt, a...) \
718 dev_printk(prefix, &(shost)->shost_gendev, fmt, ##a)
720 static inline void *shost_priv(struct Scsi_Host
*shost
)
722 return (void *)shost
->hostdata
;
725 int scsi_is_host_device(const struct device
*);
727 static inline struct Scsi_Host
*dev_to_shost(struct device
*dev
)
729 while (!scsi_is_host_device(dev
)) {
734 return container_of(dev
, struct Scsi_Host
, shost_gendev
);
737 static inline int scsi_host_in_recovery(struct Scsi_Host
*shost
)
739 return shost
->shost_state
== SHOST_RECOVERY
||
740 shost
->shost_state
== SHOST_CANCEL_RECOVERY
||
741 shost
->shost_state
== SHOST_DEL_RECOVERY
||
742 shost
->tmf_in_progress
;
745 static inline bool shost_use_blk_mq(struct Scsi_Host
*shost
)
747 return shost
->use_blk_mq
;
750 extern int scsi_queue_work(struct Scsi_Host
*, struct work_struct
*);
751 extern void scsi_flush_work(struct Scsi_Host
*);
753 extern struct Scsi_Host
*scsi_host_alloc(struct scsi_host_template
*, int);
754 extern int __must_check
scsi_add_host_with_dma(struct Scsi_Host
*,
757 extern void scsi_scan_host(struct Scsi_Host
*);
758 extern void scsi_rescan_device(struct device
*);
759 extern void scsi_remove_host(struct Scsi_Host
*);
760 extern struct Scsi_Host
*scsi_host_get(struct Scsi_Host
*);
761 extern void scsi_host_put(struct Scsi_Host
*t
);
762 extern struct Scsi_Host
*scsi_host_lookup(unsigned short);
763 extern const char *scsi_host_state_name(enum scsi_host_state
);
764 extern void scsi_cmd_get_serial(struct Scsi_Host
*, struct scsi_cmnd
*);
766 static inline int __must_check
scsi_add_host(struct Scsi_Host
*host
,
769 return scsi_add_host_with_dma(host
, dev
, dev
);
772 static inline struct device
*scsi_get_device(struct Scsi_Host
*shost
)
774 return shost
->shost_gendev
.parent
;
778 * scsi_host_scan_allowed - Is scanning of this host allowed
779 * @shost: Pointer to Scsi_Host.
781 static inline int scsi_host_scan_allowed(struct Scsi_Host
*shost
)
783 return shost
->shost_state
== SHOST_RUNNING
||
784 shost
->shost_state
== SHOST_RECOVERY
;
787 extern void scsi_unblock_requests(struct Scsi_Host
*);
788 extern void scsi_block_requests(struct Scsi_Host
*);
790 struct class_container
;
793 * These two functions are used to allocate and free a pseudo device
794 * which will connect to the host adapter itself rather than any
795 * physical device. You must deallocate when you are done with the
796 * thing. This physical pseudo-device isn't real and won't be available
797 * from any high-level drivers.
799 extern void scsi_free_host_dev(struct scsi_device
*);
800 extern struct scsi_device
*scsi_get_host_dev(struct Scsi_Host
*);
803 * DIF defines the exchange of protection information between
804 * initiator and SBC block device.
806 * DIX defines the exchange of protection information between OS and
809 enum scsi_host_prot_capabilities
{
810 SHOST_DIF_TYPE1_PROTECTION
= 1 << 0, /* T10 DIF Type 1 */
811 SHOST_DIF_TYPE2_PROTECTION
= 1 << 1, /* T10 DIF Type 2 */
812 SHOST_DIF_TYPE3_PROTECTION
= 1 << 2, /* T10 DIF Type 3 */
814 SHOST_DIX_TYPE0_PROTECTION
= 1 << 3, /* DIX between OS and HBA only */
815 SHOST_DIX_TYPE1_PROTECTION
= 1 << 4, /* DIX with DIF Type 1 */
816 SHOST_DIX_TYPE2_PROTECTION
= 1 << 5, /* DIX with DIF Type 2 */
817 SHOST_DIX_TYPE3_PROTECTION
= 1 << 6, /* DIX with DIF Type 3 */
821 * SCSI hosts which support the Data Integrity Extensions must
822 * indicate their capabilities by setting the prot_capabilities using
825 static inline void scsi_host_set_prot(struct Scsi_Host
*shost
, unsigned int mask
)
827 shost
->prot_capabilities
= mask
;
830 static inline unsigned int scsi_host_get_prot(struct Scsi_Host
*shost
)
832 return shost
->prot_capabilities
;
835 static inline int scsi_host_prot_dma(struct Scsi_Host
*shost
)
837 return shost
->prot_capabilities
>= SHOST_DIX_TYPE0_PROTECTION
;
840 static inline unsigned int scsi_host_dif_capable(struct Scsi_Host
*shost
, unsigned int target_type
)
842 static unsigned char cap
[] = { 0,
843 SHOST_DIF_TYPE1_PROTECTION
,
844 SHOST_DIF_TYPE2_PROTECTION
,
845 SHOST_DIF_TYPE3_PROTECTION
};
847 if (target_type
>= ARRAY_SIZE(cap
))
850 return shost
->prot_capabilities
& cap
[target_type
] ? target_type
: 0;
853 static inline unsigned int scsi_host_dix_capable(struct Scsi_Host
*shost
, unsigned int target_type
)
855 #if defined(CONFIG_BLK_DEV_INTEGRITY)
856 static unsigned char cap
[] = { SHOST_DIX_TYPE0_PROTECTION
,
857 SHOST_DIX_TYPE1_PROTECTION
,
858 SHOST_DIX_TYPE2_PROTECTION
,
859 SHOST_DIX_TYPE3_PROTECTION
};
861 if (target_type
>= ARRAY_SIZE(cap
))
864 return shost
->prot_capabilities
& cap
[target_type
];
870 * All DIX-capable initiators must support the T10-mandated CRC
871 * checksum. Controllers can optionally implement the IP checksum
872 * scheme which has much lower impact on system performance. Note
873 * that the main rationale for the checksum is to match integrity
874 * metadata with data. Detecting bit errors are a job for ECC memory
878 enum scsi_host_guard_type
{
879 SHOST_DIX_GUARD_CRC
= 1 << 0,
880 SHOST_DIX_GUARD_IP
= 1 << 1,
883 static inline void scsi_host_set_guard(struct Scsi_Host
*shost
, unsigned char type
)
885 shost
->prot_guard_type
= type
;
888 static inline unsigned char scsi_host_get_guard(struct Scsi_Host
*shost
)
890 return shost
->prot_guard_type
;
893 extern int scsi_host_set_state(struct Scsi_Host
*, enum scsi_host_state
);
895 #endif /* _SCSI_SCSI_HOST_H */