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/*

 *  linux/fs/proc/scsi.c

 *  (c) 1995 Michael Neuffer neuffer@goofy.zdv.uni-mainz.de

 *

 *  The original version was derived from linux/fs/proc/net.c,

 *  which is Copyright (C) 1991, 1992 Linus Torvalds.

 *  Much has been rewritten, but some of the code still remains.

 *

 *  /proc/scsi directory handling functions

 *

 *  last change: 95/07/04

 *

 *  Initial version: March '95

 *  95/05/15 Added subdirectories for each driver and show every

 *           registered HBA as a single file.

 *  95/05/30 Added rudimentary write support for parameter passing

 *  95/07/04 Fixed bugs in directory handling

 *  95/09/13 Update to support the new proc-dir tree

 *

 *  TODO: Improve support to write to the driver files

 *        Add some more comments

 */

#include <linux/errno.h>

#include <linux/sched.h>

#include <linux/proc_fs.h>

#include <linux/stat.h>

#include <linux/mm.h>

#include <asm/segment.h>

/* forward references */

static int proc_readscsi(struct inode * inode, struct file * file,

                         char * buf, int count);

static int proc_writescsi(struct inode * inode, struct file * file,

                         const char * buf, int count);

static int proc_scsilseek(struct inode *, struct file *, off_t, int);

extern void build_proc_dir_hba_entries(uint);

/* the *_get_info() functions are in the respective scsi driver code */

int (* dispatch_scsi_info_ptr) (int ino, char *buffer, char **start,

                                off_t offset, int length, int inout) = 0;

static struct file_operations proc_scsi_operations = {

    proc_scsilseek,     /* lseek   */

    proc_readscsi,      /* read    */

    proc_writescsi,     /* write   */

    proc_readdir,       /* readdir */

    NULL,               /* select  */

    NULL,               /* ioctl   */

    NULL,               /* mmap    */

    NULL,               /* no special open code    */

    NULL,               /* no special release code */

    NULL                /* can't fsync */

};

/*

 * proc directories can do almost nothing..

 */

struct inode_operations proc_scsi_inode_operations = {

    &proc_scsi_operations,  /* default scsi directory file-ops */

    NULL,           /* create      */

    proc_lookup,    /* lookup      */

    NULL,           /* link        */

    NULL,           /* unlink      */

    NULL,           /* symlink     */

    NULL,           /* mkdir       */

    NULL,           /* rmdir       */

    NULL,           /* mknod       */

    NULL,           /* rename      */

    NULL,           /* readlink    */

    NULL,           /* follow_link */

    NULL,           /* readpage    */

    NULL,           /* writepage   */

    NULL,           /* bmap        */

    NULL,           /* truncate    */

    NULL            /* permission  */

};

int get_not_present_info(char *buffer, char **start, off_t offset, int length)

{

    int len, pos, begin;

    begin = 0;

    pos = len = sprintf(buffer,

                        "No low-level scsi modules are currently present\n");

    if(pos < offset) {

        len = 0;

        begin = pos;

    }

    *start = buffer + (offset - begin);   /* Start of wanted data */

    len -= (offset - begin);

    if(len > length)

        len = length;

    return(len);

}

#define PROC_BLOCK_SIZE (3*1024)     /* 4K page size, but our output routines 

                                      * use some slack for overruns

                                      */

static int proc_readscsi(struct inode * inode, struct file * file,

                         char * buf, int count)

{

    int length;

    int bytes = count;

    int copied = 0;

    int thistime;

    char * page;

    char * start;

    if (count < -1)               /* Normally I wouldn't do this, */

        return(-EINVAL);          /* but it saves some redundant code.

                                   * Now it is possible to seek to the

                                   * end of the file */

    if (!(page = (char *) __get_free_page(GFP_KERNEL)))

        return(-ENOMEM);

    while(bytes > 0 || count == -1) {

        thistime = bytes;

        if(bytes > PROC_BLOCK_SIZE || count == -1)

            thistime = PROC_BLOCK_SIZE;

        if(dispatch_scsi_info_ptr)

            length = dispatch_scsi_info_ptr(inode->i_ino, page, &start,

                                            file->f_pos, thistime, 0);

        else

            length = get_not_present_info(page, &start, file->f_pos, thistime);

        if(length < 0) {

            free_page((ulong) page);

            return(length);

        }

        /*

         *  We have been given a non page aligned block of

         *  the data we asked for + a bit. We have been given

         *  the start pointer and we know the length..

         */

        if (length <= 0)

            break;

        /*

         *  Copy the bytes, if we're not doing a seek to

         *      the end of the file

         */

        if (count != -1)

            memcpy_tofs(buf + copied, start, length);

        file->f_pos += length;  /* Move down the file */

        bytes -= length;

        copied += length;

        if(length < thistime)

            break;  /* End of file */

    }

    free_page((ulong) page);

    return(copied);

}

static int proc_writescsi(struct inode * inode, struct file * file,

                         const char * buf, int count)

{

    int ret = 0;

    char * page;

    if(count > PROC_BLOCK_SIZE) {

        return(-EOVERFLOW);

    }

    if(dispatch_scsi_info_ptr != NULL) {

        if (!(page = (char *) __get_free_page(GFP_KERNEL)))

            return(-ENOMEM);

        memcpy_fromfs(page, buf, count);

        ret = dispatch_scsi_info_ptr(inode->i_ino, page, 0, 0, count, 1);

    } else

        return(-ENOPKG);          /* Nothing here */

    free_page((ulong) page);

    return(ret);

}

static int proc_scsilseek(struct inode * inode, struct file * file,

                          off_t offset, int orig)

{

    switch (orig) {

    case 0:

        file->f_pos = offset;

        return(file->f_pos);

    case 1:

        file->f_pos += offset;

        return(file->f_pos);

    case 2:                  /* This ugly hack allows us to    */

        if (offset)          /* to determine the length of the */

            return(-EINVAL); /* file and then later safely to  */

        proc_readscsi(inode, file, 0, -1); /* seek in it       */

        return(file->f_pos);

    default:

        return(-EINVAL);

    }

}

/*

 * Overrides for Emacs so that we almost 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:

 */