scsi_host.h

来自「Linux Kernel 2.6.9 for OMAP1710」· C头文件 代码 · 共 570 行 · 第 1/2 页

	 * 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;

	/*
	 * 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 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;

	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;

	/*
	 * 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;

	/*
	 * 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		dev_to_shost(d)		\
	container_of(d, struct Scsi_Host, shost_gendev)
#define		class_to_shost(d)	\
	container_of(d, struct Scsi_Host, shost_classdev)

extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int);
extern int scsi_add_host(struct Scsi_Host *, struct device *);
extern void scsi_scan_host(struct Scsi_Host *);
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 *);

/*
 * 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 */