root/drivers/scsi/sg.h

/* */

INCLUDED FROM

   1 /*
   2    History:
   3     Started: Aug 9 by Lawrence Foard (entropy@world.std.com), to allow user 
   4      process control of SCSI devices.
   5     Development Sponsored by Killy Corp. NY NY
   6 */
   7 
   8 /* 
   9  An SG device is accessed by writting "packets" to it, the replies
  10  are then read using the read call. The same header is used for 
  11  reply, just ignore reply_len field.
  12 */
  13 
  14 struct sg_header
  15  {
  16   int pack_len;    /* length of incoming packet <4096 (including header) */
  17   int reply_len;   /* maximum length <4096 of expected reply */
  18   int pack_id;     /* id number of packet */
  19   int result;      /* 0==ok, otherwise refer to errno codes */
  20   /* command follows then data for command */
  21  };
  22 
  23 /* ioctl's */
  24 #define SG_SET_TIMEOUT 0x2201  /* set timeout *(int *)arg==timeout */
  25 #define SG_GET_TIMEOUT 0x2202  /* get timeout return timeout */
  26 
  27 #define SG_DEFAULT_TIMEOUT 6000 /* 1 minute timeout */
  28 #define SG_DEFAULT_RETRIES 1
  29 
  30 #define SG_MAX_QUEUE 4 /* maximum outstanding request, arbitrary, may be
  31                           changed if sufficient DMA buffer room available */
  32 
  33 #define SG_BIG_BUFF 32768

/* */