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/*

 *  hosts.h Copyright (C) 1992 Drew Eckhardt

 *          Copyright (C) 1993, 1994, 1995 Eric Youngdale

 *

 *  mid to low-level SCSI driver interface header

 *      Initial versions: Drew Eckhardt

 *      Subsequent revisions: Eric Youngdale

 *

 *  <drew@colorado.edu>

 *

 *       Modified by Eric Youngdale eric@aib.com to

 *       add scatter-gather, multiple outstanding request, and other

 *       enhancements.

 *

 *  Further modified by Eric Youngdale to support multiple host adapters

 *  of the same type.

 */

#ifndef _HOSTS_H

#define _HOSTS_H

/*

    $Header: /home/marcus/revision_ctrl_test/oc_cvs/cvs/or1k/uclinux/uClinux-2.0.x/drivers/scsi/hosts.h,v 1.1.1.1 2001-09-10 07:44:33 simons Exp $

*/

#include <linux/proc_fs.h>

/* It is senseless to set SG_ALL any higher than this - the performance

 *  does not get any better, and it wastes memory

 */

#define SG_NONE 0

#define SG_ALL 0xff

#define DISABLE_CLUSTERING 0

#define ENABLE_CLUSTERING 1

/* 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.

 */

/*

 * The Scsi_Host_Template type has all that is needed to interface with a SCSI

 * host in a device independent matter.  There is one entry for each different

 * type of host adapter that is supported on the system.

 */

typedef struct scsi_disk Disk;

typedef struct  SHT

{

    /* Used with loadable modules so we can construct a linked list. */

    struct SHT * next;

    /* Used with loadable modules so that we know when it is safe to unload */

    long * usage_count;

    /* The pointer to the /proc/scsi directory entry */

    struct proc_dir_entry *proc_dir;

    /* proc-fs info function.

     * 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. Check eata_dma_proc.c for reference

     */

    int (*proc_info)(char *, char **, off_t, int, int, int);

    /*

     * The name pointer is a pointer to the name of the SCSI

     * device detected.

     */

    const char *name;

    /*

     * The detect function shall return non zero on detection,

     * indicating the number of host adapters of this particular

     * type were found.  It should also

     * initialize all data necessary for this particular

     * SCSI driver.  It is passed the host number, so this host

     * knows where the first entry is in the scsi_hosts[] array.

     *

     * Note that the detect routine MUST not call any of the mid level

     * functions to queue commands because things are not guaranteed

     * to be set up yet.  The detect routine can send commands to

     * the host adapter as long as the program control will not be

     * passed to scsi.c in the processing of the command.  Note

     * especially that scsi_malloc/scsi_free must not be called.

     */

    int (* detect)(struct SHT *);

    /* Used with loadable modules to unload the host structures.  Note:

     * there is a default action built into the modules code which may

     * be sufficient for most host adapters.  Thus you may not have to supply

     * this at all.

     */

    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.

     */

    const char *(* info)(struct Scsi_Host *);

    /*

     * The command function takes a target, a command (this is a SCSI

     * command formatted as per the SCSI spec, nothing strange), a

     * data buffer pointer, and data buffer length pointer.  The return

     * is a status int, bit fielded as follows :

     * Byte What

     * 0    SCSI status code

     * 1    SCSI 1 byte message

     * 2    host error return.

     * 3    mid level error return

     */

    int (* command)(Scsi_Cmnd *);

    /*

     * The QueueCommand function works in a similar manner

     * to the command function.  It takes an additional parameter,

     * void (* done)(int host, int code) which is passed the host

     * # and exit result when the command is complete.

     * Host number is the POSITION IN THE hosts array of THIS

     * host adapter.

     */

    int (* queuecommand)(Scsi_Cmnd *, void (*done)(Scsi_Cmnd *));

    /*

     * Since the mid level driver handles time outs, etc, we want to

     * be able to abort the current command.  Abort returns 0 if the

     * abortion was successful.  The field SCpnt->abort reason

     * can be filled in with the appropriate reason why we wanted

     * the abort in the first place, and this will be used

     * in the mid-level code instead of the host_byte().

     * If non-zero, the code passed to it

     * will be used as the return code, otherwise

     * DID_ABORT  should be returned.

     *

     * Note that the scsi driver should "clean up" after itself,

     * resetting the bus, etc.  if necessary.

     */

    int (* abort)(Scsi_Cmnd *);

    /*

     * The reset function will reset the SCSI bus.  Any executing

     * commands should fail with a DID_RESET in the host byte.

     * The Scsi_Cmnd  is passed so that the reset routine can figure

     * out which host adapter should be reset, and also which command

     * within the command block was responsible for the reset in

     * the first place.  Some hosts do not implement a reset function,

     * and these hosts must call scsi_request_sense(SCpnt) to keep

     * the command alive.

     */

    int (* reset)(Scsi_Cmnd *, unsigned int);

    /*

     * This function is used to select synchronous communications,

     * which will result in a higher data throughput.  Not implemented

     * yet.

     */

    int (* slave_attach)(int, 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 number, list (heads, sectors, cylinders)

     */

    int (* bios_param)(Disk *, kdev_t, int []);

    /*

     * 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.

     */

    short unsigned int sg_tablesize;

    /*

     * 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;

} Scsi_Host_Template;

/*

 * The scsi_hosts array is the array containing the data for all

 * possible <supported> scsi hosts.   This is similar to the

 * Scsi_Host_Template, except that we have one entry for each

 * actual physical host adapter on the system, stored as a linked

 * list.  Note that if there are 2 aha1542 boards, then there will

 * be two Scsi_Host entries, but only 1 Scsi_Host_Template entry.

 */

struct Scsi_Host

{

    struct Scsi_Host * next;

    unsigned short extra_bytes;

    volatile unsigned char host_busy;

    char host_no;  /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */

    unsigned long last_reset;

    struct wait_queue *host_wait;

    Scsi_Cmnd *host_queue;

    Scsi_Host_Template * hostt;

    /*

     *  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;

    /*

     * Pointer to a circularly linked list - this indicates the hosts

     * that should be locked out of performing I/O while we have an active

     * command on this host.

     */

    struct Scsi_Host * block;

    unsigned wish_block:1;

    /* These parameters should be set by the detect routine */

    unsigned char *base;

    unsigned int  io_port;

    unsigned char n_io_port;

    unsigned char irq;

    unsigned char dma_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 rest can be copied from the template, or specifically

     * initialized, as required.

     */

    int this_id;

    int can_queue;

    short cmd_per_lun;

    short unsigned int sg_tablesize;

    unsigned unchecked_isa_dma:1;

    unsigned use_clustering:1;

    /*

     * True if this host was loaded as a loadable module

     */

    unsigned loaded_as_module:1;

    void (*select_queue_depths)(struct Scsi_Host *, Scsi_Device *);

    unsigned long hostdata[0];  /* Used for storage of host specific stuff */

};

extern struct Scsi_Host * scsi_hostlist;

extern struct Scsi_Device_Template * scsi_devicelist;

extern Scsi_Host_Template * scsi_hosts;

extern void build_proc_dir_entries(Scsi_Host_Template  *);

/*

 *  scsi_init initializes the scsi hosts.

 */

/*

 * We use these goofy things because the MM is not set up when we init

 * the scsi subsystem.  By using these functions we can write code that

 * looks normal.  Also, it makes it possible to use the same code for a

 * loadable module.

 */

extern void * scsi_init_malloc(unsigned int size, int priority);

extern void scsi_init_free(char * ptr, unsigned int size);

extern int next_scsi_host;

extern int scsi_loadable_module_flag;

unsigned int scsi_init(void);

extern struct Scsi_Host * scsi_register(Scsi_Host_Template *, int j);

extern void scsi_unregister(struct Scsi_Host * i);

#define BLANK_HOST {"", 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}

struct Scsi_Device_Template

{

    struct Scsi_Device_Template * next;

    const char * name;

    const char * tag;

    long * usage_count;           /* Used for loadable modules */

    unsigned char scsi_type;

    unsigned char major;

    unsigned char nr_dev;         /* Number currently attached */

    unsigned char dev_noticed;    /* Number of devices detected. */

    unsigned char dev_max;        /* Current size of arrays */

    unsigned blk:1;               /* 0 if character device */

    int (*detect)(Scsi_Device *); /* Returns 1 if we can attach this device */

    int (*init)(void);            /* Sizes arrays based upon number of devices

                   *  detected */

    void (*finish)(void);         /* Perform initialization after attachment */

    int (*attach)(Scsi_Device *); /* Attach devices to arrays */

    void (*detach)(Scsi_Device *);

};

extern struct Scsi_Device_Template sd_template;

extern struct Scsi_Device_Template st_template;

extern struct Scsi_Device_Template sr_template;

extern struct Scsi_Device_Template sg_template;

int scsi_register_device(struct Scsi_Device_Template * sdpnt);

/* These are used by loadable modules */

extern int scsi_register_module(int, void *);

extern void scsi_unregister_module(int, void *);

/* The different types of modules that we can load and unload */

#define MODULE_SCSI_HA 1

#define MODULE_SCSI_CONST 2

#define MODULE_SCSI_IOCTL 3

#define MODULE_SCSI_DEV 4

/*

 * This is an ugly hack.  If we expect to be able to load devices at run time,

 * we need to leave extra room in some of the data structures.  Doing a

 * realloc to enlarge the structures would be riddled with race conditions,

 * so until a better solution is discovered, we use this crude approach

 */

#define SD_EXTRA_DEVS 2

#define ST_EXTRA_DEVS 2

#define SR_EXTRA_DEVS 2

#define SG_EXTRA_DEVS (SD_EXTRA_DEVS + SR_EXTRA_DEVS + ST_EXTRA_DEVS)

#endif

/*

 * Overrides for Emacs so that we follow Linus's tabbing style.

 * Emacs will notice this stuff at the end of the file and automatically

 * adjust the settings for this buffer only.  This must remain at the end

 * of the file.

 * ---------------------------------------------------------------------------

 * Local variables:

 * c-indent-level: 4

 * c-brace-imaginary-offset: 0

 * c-brace-offset: -4

 * c-argdecl-indent: 4

 * c-label-offset: -4

 * c-continued-statement-offset: 4

 * c-continued-brace-offset: 0

 * indent-tabs-mode: nil

 * tab-width: 8

 * End:

 */