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C/C++ Source or Header | 2006-08-11 | 21.0 KB | 681 lines

#ifndef _SCSI_SCSI_HOST_H #define _SCSI_SCSI_HOST_H #include <linux/device.h> #include <linux/list.h> #include <linux/types.h> #include <linux/workqueue.h> #include <linux/mutex.h> struct block_device; struct completion; struct module; struct scsi_cmnd; struct scsi_device; struct scsi_target; struct Scsi_Host; struct scsi_host_cmd_pool; struct scsi_transport_template; /* * The various choices mean: * NONE: Self evident. Host adapter is not capable of scatter-gather. * ALL: Means that the host adapter module can do scatter-gather, * and that there is no limit to the size of the table to which * we scatter/gather data. * Anything else: Indicates the maximum number of chains that can be * used in one scatter-gather request. */ #define SG_NONE 0 #define SG_ALL 0xff #define DISABLE_CLUSTERING 0 #define ENABLE_CLUSTERING 1 enum scsi_eh_timer_return { EH_NOT_HANDLED, EH_HANDLED, EH_RESET_TIMER, }; struct scsi_host_template { struct module *module; const char *name; /* * Used to initialize old-style drivers. For new-style drivers * just perform all work in your module initialization function. * * Status: OBSOLETE */ int (* detect)(struct scsi_host_template *); /* * Used as unload callback for hosts with old-style drivers. * * Status: OBSOLETE */ int (* release)(struct Scsi_Host *); /* * The info function will return whatever useful information the * developer sees fit. If not provided, then the name field will * be used instead. * * Status: OPTIONAL */ const char *(* info)(struct Scsi_Host *); /* * Ioctl interface * * Status: OPTIONAL */ int (* ioctl)(struct scsi_device *dev, int cmd, void __user *arg); #ifdef CONFIG_COMPAT /* * Compat handler. Handle 32bit ABI. * When unknown ioctl is passed return -ENOIOCTLCMD. * * Status: OPTIONAL */ int (* compat_ioctl)(struct scsi_device *dev, int cmd, void __user *arg); #endif /* * The queuecommand function is used to queue up a scsi * command block to the LLDD. When the driver finished * processing the command the done callback is invoked. * * If queuecommand returns 0, then the HBA has accepted the * command. The done() function must be called on the command * when the driver has finished with it. (you may call done on the * command before queuecommand returns, but in this case you * *must* return 0 from queuecommand). * * Queuecommand may also reject the command, in which case it may * not touch the command and must not call done() for it. * * There are two possible rejection returns: * * SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but * allow commands to other devices serviced by this host. * * SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this * host temporarily. * * For compatibility, any other non-zero return is treated the * same as SCSI_MLQUEUE_HOST_BUSY. * * NOTE: "temporarily" means either until the next command for# * this device/host completes, or a period of time determined by * I/O pressure in the system if there are no other outstanding * commands. * * STATUS: REQUIRED */ int (* queuecommand)(struct scsi_cmnd *, void (*done)(struct scsi_cmnd *)); /* * This is an error handling strategy routine. You don't need to * define one of these if you don't want to - there is a default * routine that is present that should work in most cases. For those * driver authors that have the inclination and ability to write their * own strategy routine, this is where it is specified. Note - the * strategy routine is *ALWAYS* run in the context of the kernel eh * thread. Thus you are guaranteed to *NOT* be in an interrupt * handler when you execute this, and you are also guaranteed to * *NOT* have any other commands being queued while you are in the * strategy routine. When you return from this function, operations * return to normal. * * See scsi_error.c scsi_unjam_host for additional comments about * what this function should and should not be attempting to do. * * Status: REQUIRED (at least one of them) */ int (* eh_abort_handler)(struct scsi_cmnd *); int (* eh_device_reset_handler)(struct scsi_cmnd *); int (* eh_bus_reset_handler)(struct scsi_cmnd *); int (* eh_host_reset_handler)(struct scsi_cmnd *); /* * Before the mid layer attempts to scan for a new device where none * currently exists, it will call this entry in your driver. Should * your driver need to allocate any structs or perform any other init * items in order to send commands to a currently unused target/lun * combo, then this is where you can perform those allocations. This * is specifically so that drivers won't have to perform any kind of * "is this a new device" checks in their queuecommand routine, * thereby making the hot path a bit quicker. * * Return values: 0 on success, non-0 on failure * * Deallocation: If we didn't find any devices at this ID, you will * get an immediate call to slave_destroy(). If we find something * here then you will get a call to slave_configure(), then the * device will be used for however long it is kept around, then when * the device is removed from the system (or * possibly at reboot * time), you will then get a call to slave_destroy(). This is * assuming you implement slave_configure and slave_destroy. * However, if you allocate memory and hang it off the device struct, * then you must implement the slave_destroy() routine at a minimum * in order to avoid leaking memory * each time a device is tore down. * * Status: OPTIONAL */ int (* slave_alloc)(struct scsi_device *); /* * Once the device has responded to an INQUIRY and we know the * device is online, we call into the low level driver with the * struct scsi_device *. If the low level device driver implements * this function, it *must* perform the task of setting the queue * depth on the device. All other tasks are optional and depend * on what the driver supports and various implementation details. * * Things currently recommended to be handled at this time include: * * 1. Setting the device queue depth. Proper setting of this is * described in the comments for scsi_adjust_queue_depth. * 2. Determining if the device supports the various synchronous * negotiation protocols. The device struct will already have * responded to INQUIRY and the results of the standard items * will have been shoved into the various device flag bits, eg. * device->sdtr will be true if the device supports SDTR messages. * 3. Allocating command structs that the device will need. * 4. Setting the default timeout on this device (if needed). * 5. Anything else the low level driver might want to do on a device * specific setup basis... * 6. Return 0 on success, non-0 on error. The device will be marked * as offline on error so that no access will occur. If you return * non-0, your slave_destroy routine will never get called for this * device, so don't leave any loose memory hanging around, clean * up after yourself before returning non-0 * * Status: OPTIONAL */ int (* slave_configure)(struct scsi_device *); /* * Immediately prior to deallocating the device and after all activity * has ceased the mid layer calls this point so that the low level * driver may completely detach itself from the scsi device and vice * versa. The low level driver is responsible for freeing any memory * it allocated in the slave_alloc or slave_configure calls. * * Status: OPTIONAL */ void (* slave_destroy)(struct scsi_device *); /* * Before the mid layer attempts to scan for a new device attached * to a target where no target currently exists, it will call this * entry in your driver. Should your driver need to allocate any * structs or perform any other init items in order to send commands * to a currently unused target, then this is where you can perform * those allocations. * * Return values: 0 on success, non-0 on failure * * Status: OPTIONAL */ int (* target_alloc)(struct scsi_target *); /* * Immediately prior to deallocating the target structure, and * after all activity to attached scsi devices has ceased, the * midlayer calls this point so that the driver may deallocate * and terminate any references to the target. * * Status: OPTIONAL */ void (* target_destroy)(struct scsi_target *); /* * fill in this function to allow the queue depth of this host * to be changeable (on a per device basis). returns either * the current queue depth setting (may be different from what * was passed in) or an error. An error should only be * returned if the requested depth is legal but the driver was * unable to set it. If the requested depth is illegal, the * driver should set and return the closest legal queue depth. * */ int (* change_queue_depth)(struct scsi_device *, int); /* * fill in this function to allow the changing of tag types * (this also allows the enabling/disabling of tag command * queueing). An error should only be returned if something * went wrong in the driver while trying to set the tag type. * If the driver doesn't support the requested tag type, then * it should set the closest type it does support without * returning an error. Returns the actual tag type set. */ int (* change_queue_type)(struct scsi_device *, int); /* * This function determines the bios parameters for a given * harddisk. These tend to be numbers that are made up by * the host adapter. Parameters: * size, device, list (heads, sectors, cylinders) * * Status: OPTIONAL */ int (* bios_param)(struct scsi_device *, struct block_device *, sector_t, int []); /* * Can be used to export driver statistics and other infos to the * world outside the kernel ie. userspace and it also provides an * interface to feed the driver with information. * * Status: OBSOLETE */ int (*proc_info)(struct Scsi_Host *, char *, char **, off_t, int, int); /* * suspend support */ int (*resume)(struct scsi_device *); int (*suspend)(struct scsi_device *, pm_message_t state); /* * Name of proc directory */ char *proc_name; /* * Used to store the procfs directory if a driver implements the * proc_info method. */ struct proc_dir_entry *proc_dir; /* * This determines if we will use a non-interrupt driven * or an interrupt driven scheme, It is set to the maximum number * of simultaneous commands a given host adapter will accept. */ int can_queue; /* * In many instances, especially where disconnect / reconnect are * supported, our host also has an ID on the SCSI bus. If this is * the case, then it must be reserved. Please set this_id to -1 if * your setup is in single initiator mode, and the host lacks an * ID. */ int this_id; /* * This determines the degree to which the host adapter is capable * of scatter-gather. */ unsigned short sg_tablesize; /* * If the host adapter has limitations beside segment count */ unsigned short max_sectors; /* * dma scatter gather segment boundary limit. a segment crossing this * boundary will be split in two. */ unsigned long dma_boundary; /* * This specifies "machine infinity" for host templates which don't * limit the transfer size. Note this limit represents an absolute * maximum, and may be over the transfer limits allowed for * individual devices (e.g. 256 for SCSI-1) */ #define SCSI_DEFAULT_MAX_SECTORS 1024 /* * True if this host adapter can make good use of linked commands. * This will allow more than one command to be queued to a given * unit on a given host. Set this to the maximum number of command * blocks to be provided for each device. Set this to 1 for one * command block per lun, 2 for two, etc. Do not set this to 0. * You should make sure that the host adapter will do the right thing * before you try setting this above 1. */ short cmd_per_lun; /* * present contains counter indicating how many boards of this * type were found when we did the scan. */ unsigned char present; /* * true if this host adapter uses unchecked DMA onto an ISA bus. */ unsigned unchecked_isa_dma:1; /* * true if this host adapter can make good use of clustering. * I originally thought that if the tablesize was large that it * was a waste of CPU cycles to prepare a cluster list, but * it works out that the Buslogic is faster if you use a smaller * number of segments (i.e. use clustering). I guess it is * inefficient. */ unsigned use_clustering:1; /* * True for emulated SCSI host adapters (e.g. ATAPI) */ unsigned emulated:1; /* * True if the low-level driver performs its own reset-settle delays. */ unsigned skip_settle_delay:1; /* * ordered write support */ unsigned ordered_tag:1; /* * Countdown for host blocking with no commands outstanding */ unsigned int max_host_blocked; /* * Default value for the blocking. If the queue is empty, * host_blocked counts down in the request_fn until it restarts * host operations as zero is reached. * * FIXME: This should probably be a value in the template */ #define SCSI_DEFAULT_HOST_BLOCKED 7 /* * Pointer to the sysfs class properties for this host, NULL terminated. */ struct class_device_attribute **shost_attrs; /* * Pointer to the SCSI device properties for this host, NULL terminated. */ struct device_attribute **sdev_attrs; /* * List of hosts per template. * * This is only for use by scsi_module.c for legacy templates. * For these access to it is synchronized implicitly by * module_init/module_exit. */ struct list_head legacy_hosts; }; /* * shost state: If you alter this, you also need to alter scsi_sysfs.c * (for the ascii descriptions) and the state model enforcer: * scsi_host_set_state() */ enum scsi_host_state { SHOST_CREATED = 1, SHOST_RUNNING, SHOST_CANCEL, SHOST_DEL, SHOST_RECOVERY, SHOST_CANCEL_RECOVERY, SHOST_DEL_RECOVERY, }; struct Scsi_Host { /* * __devices is protected by the host_lock, but you should * usually use scsi_device_lookup / shost_for_each_device * to access it and don't care about locking yourself. * In the rare case of beeing in irq context you can use * their __ prefixed variants with the lock held. NEVER * access this list directly from a driver. */ struct list_head __devices; struct list_head __targets; struct scsi_host_cmd_pool *cmd_pool; spinlock_t free_list_lock; struct list_head free_list; /* backup store of cmd structs */ struct list_head starved_list; spinlock_t default_lock; spinlock_t *host_lock; struct mutex scan_mutex;/* serialize scanning activity */ struct list_head eh_cmd_q; struct task_struct * ehandler; /* Error recovery thread. */ struct completion * eh_action; /* Wait for specific actions on the host. */ wait_queue_head_t host_wait; struct scsi_host_template *hostt; struct scsi_transport_template *transportt; /* * The following two fields are protected with host_lock; * however, eh routines can safely access during eh processing * without acquiring the lock. */ unsigned int host_busy; /* commands actually active on low-level */ unsigned int host_failed; /* commands that failed. */ unsigned short host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */ int resetting; /* if set, it means that last_reset is a valid value */ unsigned long last_reset; /* * These three parameters can be used to allow for wide scsi, * and for host adapters that support multiple busses * The first two should be set to 1 more than the actual max id * or lun (i.e. 8 for normal systems). */ unsigned int max_id; unsigned int max_lun; unsigned int max_channel; /* * This is a unique identifier that must be assigned so that we * have some way of identifying each detected host adapter properly * and uniquely. For hosts that do not support more than one card * in the system at one time, this does not need to be set. It is * initialized to 0 in scsi_register. */ unsigned int unique_id; /* * The maximum length of SCSI commands that this host can accept. * Probably 12 for most host adapters, but could be 16 for others. * For drivers that don't set this field, a value of 12 is * assumed. I am leaving this as a number rather than a bit * because you never know what subsequent SCSI standards might do * (i.e. could there be a 20 byte or a 24-byte command a few years * down the road?). */ unsigned char max_cmd_len; int this_id; int can_queue; short cmd_per_lun; short unsigned int sg_tablesize; short unsigned int max_sectors; unsigned long dma_boundary; /* * Used to assign serial numbers to the cmds. * Protected by the host lock. */ unsigned long cmd_serial_number, cmd_pid; unsigned unchecked_isa_dma:1; unsigned use_clustering:1; unsigned use_blk_tcq:1; /* * Host has requested that no further requests come through for the * time being. */ unsigned host_self_blocked:1; /* * Host uses correct SCSI ordering not PC ordering. The bit is * set for the minority of drivers whose authors actually read * the spec ;) */ unsigned reverse_ordering:1; /* * ordered write support */ unsigned ordered_tag:1; /* Are we currently performing an async scan? */ unsigned async_scan:1; /* * Optional work queue to be utilized by the transport */ char work_q_name[KOBJ_NAME_LEN]; struct workqueue_struct *work_q; /* * Host has rejected a command because it was busy. */ unsigned int host_blocked; /* * Value host_blocked counts down from */ unsigned int max_host_blocked; /* legacy crap */ unsigned long base; unsigned long io_port; unsigned char n_io_port; unsigned char dma_channel; unsigned int irq; enum scsi_host_state shost_state; /* ldm bits */ struct device shost_gendev; struct class_device shost_classdev; /* * List of hosts per template. * * This is only for use by scsi_module.c for legacy templates. * For these access to it is synchronized implicitly by * module_init/module_exit. */ struct list_head sht_legacy_list; /* * Points to the transport data (if any) which is allocated * separately */ void *shost_data; /* * We should ensure that this is aligned, both for better performance * and also because some compilers (m68k) don't automatically force * alignment to a long boundary. */ unsigned long hostdata[0] /* Used for storage of host specific stuff */ __attribute__ ((aligned (sizeof(unsigned long)))); }; #define class_to_shost(d) \ container_of(d, struct Scsi_Host, shost_classdev) #define shost_printk(prefix, shost, fmt, a...) \ dev_printk(prefix, &(shost)->shost_gendev, fmt, ##a) int scsi_is_host_device(const struct device *); static inline struct Scsi_Host *dev_to_shost(struct device *dev) { while (!scsi_is_host_device(dev)) { if (!dev->parent) return NULL; dev = dev->parent; } return container_of(dev, struct Scsi_Host, shost_gendev); } static inline int scsi_host_in_recovery(struct Scsi_Host *shost) { return shost->shost_state == SHOST_RECOVERY || shost->shost_state == SHOST_CANCEL_RECOVERY || shost->shost_state == SHOST_DEL_RECOVERY; } extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *); extern void scsi_flush_work(struct Scsi_Host *); extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int); extern int __must_check scsi_add_host(struct Scsi_Host *, struct device *); extern void scsi_scan_host(struct Scsi_Host *); extern void scsi_rescan_device(struct device *); extern void scsi_remove_host(struct Scsi_Host *); extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *); extern void scsi_host_put(struct Scsi_Host *t); extern struct Scsi_Host *scsi_host_lookup(unsigned short); extern const char *scsi_host_state_name(enum scsi_host_state); extern u64 scsi_calculate_bounce_limit(struct Scsi_Host *); static inline void scsi_assign_lock(struct Scsi_Host *shost, spinlock_t *lock) { shost->host_lock = lock; } static inline struct device *scsi_get_device(struct Scsi_Host *shost) { return shost->shost_gendev.parent; } /** * scsi_host_scan_allowed - Is scanning of this host allowed * @shost: Pointer to Scsi_Host. **/ static inline int scsi_host_scan_allowed(struct Scsi_Host *shost) { return shost->shost_state == SHOST_RUNNING; } extern void scsi_unblock_requests(struct Scsi_Host *); extern void scsi_block_requests(struct Scsi_Host *); struct class_container; /* * These two functions are used to allocate and free a pseudo device * which will connect to the host adapter itself rather than any * physical device. You must deallocate when you are done with the * thing. This physical pseudo-device isn't real and won't be available * from any high-level drivers. */ extern void scsi_free_host_dev(struct scsi_device *); extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *); /* legacy interfaces */ extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int); extern void scsi_unregister(struct Scsi_Host *); extern int scsi_host_set_state(struct Scsi_Host *, enum scsi_host_state); #endif /* _SCSI_SCSI_HOST_H */