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Diffstat (limited to 'include/scsi/scsi_host.h')
| -rw-r--r-- | include/scsi/scsi_host.h | 642 |
1 files changed, 642 insertions, 0 deletions
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h new file mode 100644 index 000000000000..27f2c4e8943a --- /dev/null +++ b/include/scsi/scsi_host.h @@ -0,0 +1,642 @@ +#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> + +struct block_device; +struct module; +struct scsi_cmnd; +struct scsi_device; +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 + * + * Status: OBSOLETE + */ + int (* detect)(struct scsi_host_template *); + + /* + * Used as unload callback for hosts with old-style drivers. + * + * Status: OBSOLETE + */ + int (* release)(struct Scsi_Host *); + + /* + * The info function will return whatever useful information the + * developer sees fit.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_strategy_handler)(struct Scsi_Host *); + 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 *); + + /* + * This is an optional routine to notify the host that the scsi + * timer just fired. The returns tell the timer routine what to + * do about this: + * + * EH_HANDLED: I fixed the error, please complete the command + * EH_RESET_TIMER: I need more time, reset the timer and + * begin counting again + * EH_NOT_HANDLED Begin normal error recovery + * + * Status: OPTIONAL + */ + enum scsi_eh_timer_return (* eh_timed_out)(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 *); + + /* + * 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); + + /* + * 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_flush:1; + 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 states + */ +enum { + SHOST_ADD, + SHOST_DEL, + SHOST_CANCEL, + SHOST_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 semaphore scan_mutex;/* serialize scanning activity */ + + struct list_head eh_cmd_q; + struct task_struct * ehandler; /* Error recovery thread. */ + struct semaphore * eh_wait; /* The error recovery thread waits + on this. */ + struct completion * eh_notify; /* wait for eh to begin or end */ + struct semaphore * eh_action; /* Wait for specific actions on the + host. */ + unsigned int eh_active:1; /* Indicates the eh thread is awake and active if + this is true. */ + unsigned int eh_kill:1; /* set when killing the eh thread */ + wait_queue_head_t host_wait; + struct scsi_host_template *hostt; + struct scsi_transport_template *transportt; + volatile unsigned short host_busy; /* commands actually active on low-level */ + volatile unsigned short 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_flush:1; + unsigned ordered_tag: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; + + + unsigned long 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) + +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); +} + +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_scan_single_target(struct Scsi_Host *, unsigned int, + unsigned int); +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 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 void scsi_set_device(struct Scsi_Host *shost, + struct device *dev) +{ + shost->shost_gendev.parent = dev; +} + +static inline struct device *scsi_get_device(struct Scsi_Host *shost) +{ + return shost->shost_gendev.parent; +} + +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 *); + +#endif /* _SCSI_SCSI_HOST_H */ |