LCOV - code coverage report
Current view: top level - include/scsi - sg.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 7 7 100.0 %
Date: 2017-01-25 Functions: 0 0 -

          Line data    Source code
       1             : #ifndef _SCSI_GENERIC_H
       2             : #define _SCSI_GENERIC_H
       3             : 
       4             : #include <linux/compiler.h>
       5             : 
       6             : /*
       7             :    History:
       8             :     Started: Aug 9 by Lawrence Foard (entropy@world.std.com), to allow user
       9             :      process control of SCSI devices.
      10             :     Development Sponsored by Killy Corp. NY NY
      11             : Original driver (sg.h):
      12             : *       Copyright (C) 1992 Lawrence Foard
      13             : Version 2 and 3 extensions to driver:
      14             : *       Copyright (C) 1998 - 2006 Douglas Gilbert
      15             : 
      16             :     Version: 3.5.34 (20060920)
      17             :     This version is for 2.6 series kernels.
      18             : 
      19             :     For a full changelog see http://www.torque.net/sg
      20             : 
      21             : Map of SG verions to the Linux kernels in which they appear:
      22             :        ----------        ----------------------------------
      23             :        original          all kernels < 2.2.6
      24             :        2.1.40            2.2.20
      25             :        3.0.x             optional version 3 sg driver for 2.2 series
      26             :        3.1.17++          2.4.0++
      27             :        3.5.30++          2.6.0++
      28             : 
      29             : Major new features in SG 3.x driver (cf SG 2.x drivers)
      30             :         - SG_IO ioctl() combines function if write() and read()
      31             :         - new interface (sg_io_hdr_t) but still supports old interface
      32             :         - scatter/gather in user space, direct IO, and mmap supported
      33             : 
      34             :  The normal action of this driver is to use the adapter (HBA) driver to DMA
      35             :  data into kernel buffers and then use the CPU to copy the data into the 
      36             :  user space (vice versa for writes). That is called "indirect" IO due to 
      37             :  the double handling of data. There are two methods offered to remove the
      38             :  redundant copy: 1) direct IO and 2) using the mmap() system call to map
      39             :  the reserve buffer (this driver has one reserve buffer per fd) into the
      40             :  user space. Both have their advantages.
      41             :  In terms of absolute speed mmap() is faster. If speed is not a concern, 
      42             :  indirect IO should be fine. Read the documentation for more information.
      43             : 
      44             :  ** N.B. To use direct IO 'echo 1 > /proc/scsi/sg/allow_dio' or
      45             :          'echo 1 > /sys/module/sg/parameters/allow_dio' is needed.
      46             :          That attribute is 0 by default. **
      47             :  
      48             :  Historical note: this SCSI pass-through driver has been known as "sg" for 
      49             :  a decade. In broader kernel discussions "sg" is used to refer to scatter
      50             :  gather techniques. The context should clarify which "sg" is referred to.
      51             : 
      52             :  Documentation
      53             :  =============
      54             :  A web site for the SG device driver can be found at:
      55             :         http://www.torque.net/sg  [alternatively check the MAINTAINERS file]
      56             :  The documentation for the sg version 3 driver can be found at:
      57             :         http://www.torque.net/sg/p/sg_v3_ho.html
      58             :  This is a rendering from DocBook source [change the extension to "sgml"
      59             :  or "xml"]. There are renderings in "ps", "pdf", "rtf" and "txt" (soon).
      60             :  The SG_IO ioctl is now found in other parts kernel (e.g. the block layer).
      61             :  For more information see http://www.torque.net/sg/sg_io.html
      62             : 
      63             :  The older, version 2 documents discuss the original sg interface in detail:
      64             :         http://www.torque.net/sg/p/scsi-generic.txt
      65             :         http://www.torque.net/sg/p/scsi-generic_long.txt
      66             :  Also available: <kernel_source>/Documentation/scsi/scsi-generic.txt
      67             : 
      68             :  Utility and test programs are available at the sg web site. They are 
      69             :  packaged as sg3_utils (for the lk 2.4 and 2.6 series) and sg_utils
      70             :  (for the lk 2.2 series).
      71             : */
      72             : 
      73             : 
      74             : /* New interface introduced in the 3.x SG drivers follows */
      75             : 
      76             : typedef struct sg_iovec /* same structure as used by readv() Linux system */
      77             : {                       /* call. It defines one scatter-gather element. */
      78             :     void __user *iov_base;      /* Starting address  */
      79             :     size_t iov_len;             /* Length in bytes  */
      80             : } sg_iovec_t;
      81           1 : 
      82             : 
      83             : typedef struct sg_io_hdr
      84             : {
      85             :     int interface_id;           /* [i] 'S' for SCSI generic (required) */
      86             :     int dxfer_direction;        /* [i] data transfer direction  */
      87             :     unsigned char cmd_len;      /* [i] SCSI command length ( <= 16 bytes) */
      88             :     unsigned char mx_sb_len;    /* [i] max length to write to sbp */
      89             :     unsigned short iovec_count; /* [i] 0 implies no scatter gather */
      90             :     unsigned int dxfer_len;     /* [i] byte count of data transfer */
      91             :     void __user *dxferp;        /* [i], [*io] points to data transfer memory
      92             :                                               or scatter gather list */
      93             :     unsigned char __user *cmdp; /* [i], [*i] points to command to perform */
      94             :     void __user *sbp;           /* [i], [*o] points to sense_buffer memory */
      95             :     unsigned int timeout;       /* [i] MAX_UINT->no timeout (unit: millisec) */
      96             :     unsigned int flags;         /* [i] 0 -> default, see SG_FLAG... */
      97             :     int pack_id;                /* [i->o] unused internally (normally) */
      98             :     void __user * usr_ptr;      /* [i->o] unused internally */
      99             :     unsigned char status;       /* [o] scsi status */
     100             :     unsigned char masked_status;/* [o] shifted, masked scsi status */
     101             :     unsigned char msg_status;   /* [o] messaging level data (optional) */
     102             :     unsigned char sb_len_wr;    /* [o] byte count actually written to sbp */
     103             :     unsigned short host_status; /* [o] errors from host adapter */
     104             :     unsigned short driver_status;/* [o] errors from software driver */
     105             :     int resid;                  /* [o] dxfer_len - actual_transferred */
     106             :     unsigned int duration;      /* [o] time taken by cmd (unit: millisec) */
     107             :     unsigned int info;          /* [o] auxiliary information */
     108           1 : } sg_io_hdr_t;  /* 64 bytes long (on i386) */
     109           1 : 
     110             : #define SG_INTERFACE_ID_ORIG 'S'
     111             : 
     112             : /* Use negative values to flag difference from original sg_header structure */
     113             : #define SG_DXFER_NONE (-1)      /* e.g. a SCSI Test Unit Ready command */
     114             : #define SG_DXFER_TO_DEV (-2)    /* e.g. a SCSI WRITE command */
     115             : #define SG_DXFER_FROM_DEV (-3)  /* e.g. a SCSI READ command */
     116             : #define SG_DXFER_TO_FROM_DEV (-4) /* treated like SG_DXFER_FROM_DEV with the
     117             :                                    additional property than during indirect
     118             :                                    IO the user buffer is copied into the
     119             :                                    kernel buffers before the transfer */
     120             : #define SG_DXFER_UNKNOWN (-5)   /* Unknown data direction */
     121             : 
     122             : /* following flag values can be "or"-ed together */
     123             : #define SG_FLAG_DIRECT_IO 1     /* default is indirect IO */
     124             : #define SG_FLAG_UNUSED_LUN_INHIBIT 2   /* default is overwrite lun in SCSI */
     125             :                                 /* command block (when <= SCSI_2) */
     126             : #define SG_FLAG_MMAP_IO 4       /* request memory mapped IO */
     127             : #define SG_FLAG_NO_DXFER 0x10000 /* no transfer of kernel buffers to/from */
     128             :                                 /* user space (debug indirect IO) */
     129             : 
     130             : /* following 'info' values are "or"-ed together */
     131             : #define SG_INFO_OK_MASK 0x1
     132             : #define SG_INFO_OK 0x0          /* no sense, host nor driver "noise" */
     133             : #define SG_INFO_CHECK 0x1       /* something abnormal happened */
     134             : 
     135             : #define SG_INFO_DIRECT_IO_MASK 0x6
     136             : #define SG_INFO_INDIRECT_IO 0x0 /* data xfer via kernel buffers (or no xfer) */
     137             : #define SG_INFO_DIRECT_IO 0x2   /* direct IO requested and performed */
     138             : #define SG_INFO_MIXED_IO 0x4    /* part direct, part indirect IO */
     139             : 
     140             : 
     141             : typedef struct sg_scsi_id { /* used by SG_GET_SCSI_ID ioctl() */
     142             :     int host_no;        /* as in "scsi<n>" where 'n' is one of 0, 1, 2 etc */
     143             :     int channel;
     144             :     int scsi_id;        /* scsi id of target device */
     145             :     int lun;
     146             :     int scsi_type;      /* TYPE_... defined in scsi/scsi.h */
     147             :     short h_cmd_per_lun;/* host (adapter) maximum commands per lun */
     148             :     short d_queue_depth;/* device (or adapter) maximum queue length */
     149             :     int unused[2];      /* probably find a good use, set 0 for now */
     150           1 : } sg_scsi_id_t; /* 32 bytes long on i386 */
     151           1 : 
     152             : typedef struct sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */
     153             :     char req_state;     /* 0 -> not used, 1 -> written, 2 -> ready to read */
     154             :     char orphan;        /* 0 -> normal request, 1 -> from interruped SG_IO */
     155             :     char sg_io_owned;   /* 0 -> complete with read(), 1 -> owned by SG_IO */
     156             :     char problem;       /* 0 -> no problem detected, 1 -> error to report */
     157             :     int pack_id;        /* pack_id associated with request */
     158             :     void __user *usr_ptr;     /* user provided pointer (in new interface) */
     159             :     unsigned int duration; /* millisecs elapsed since written (req_state==1)
     160             :                               or request duration (req_state==2) */
     161             :     int unused;
     162           1 : } sg_req_info_t; /* 20 bytes long on i386 */
     163             : 
     164             : 
     165             : /* IOCTLs: Those ioctls that are relevant to the SG 3.x drivers follow.
     166             :  [Those that only apply to the SG 2.x drivers are at the end of the file.]
     167             :  (_GET_s yield result via 'int *' 3rd argument unless otherwise indicated) */
     168             : 
     169             : #define SG_EMULATED_HOST 0x2203 /* true for emulated host adapter (ATAPI) */
     170             : 
     171             : /* Used to configure SCSI command transformation layer for ATAPI devices */
     172             : /* Only supported by the ide-scsi driver */
     173             : #define SG_SET_TRANSFORM 0x2204 /* N.B. 3rd arg is not pointer but value: */
     174             :                       /* 3rd arg = 0 to disable transform, 1 to enable it */
     175             : #define SG_GET_TRANSFORM 0x2205
     176             : 
     177             : #define SG_SET_RESERVED_SIZE 0x2275  /* request a new reserved buffer size */
     178             : #define SG_GET_RESERVED_SIZE 0x2272  /* actual size of reserved buffer */
     179             : 
     180             : /* The following ioctl has a 'sg_scsi_id_t *' object as its 3rd argument. */
     181             : #define SG_GET_SCSI_ID 0x2276   /* Yields fd's bus, chan, dev, lun + type */
     182             : /* SCSI id information can also be obtained from SCSI_IOCTL_GET_IDLUN */
     183             : 
     184             : /* Override host setting and always DMA using low memory ( <16MB on i386) */
     185             : #define SG_SET_FORCE_LOW_DMA 0x2279  /* 0-> use adapter setting, 1-> force */
     186             : #define SG_GET_LOW_DMA 0x227a   /* 0-> use all ram for dma; 1-> low dma ram */
     187             : 
     188             : /* When SG_SET_FORCE_PACK_ID set to 1, pack_id is input to read() which
     189             :    tries to fetch a packet with a matching pack_id, waits, or returns EAGAIN.
     190             :    If pack_id is -1 then read oldest waiting. When ...FORCE_PACK_ID set to 0
     191             :    then pack_id ignored by read() and oldest readable fetched. */
     192             : #define SG_SET_FORCE_PACK_ID 0x227b
     193             : #define SG_GET_PACK_ID 0x227c /* Yields oldest readable pack_id (or -1) */
     194             : 
     195             : #define SG_GET_NUM_WAITING 0x227d /* Number of commands awaiting read() */
     196             : 
     197             : /* Yields max scatter gather tablesize allowed by current host adapter */
     198             : #define SG_GET_SG_TABLESIZE 0x227F  /* 0 implies can't do scatter gather */
     199             : 
     200             : #define SG_GET_VERSION_NUM 0x2282 /* Example: version 2.1.34 yields 20134 */
     201             : 
     202             : /* Returns -EBUSY if occupied. 3rd argument pointer to int (see next) */
     203             : #define SG_SCSI_RESET 0x2284
     204             : /* Associated values that can be given to SG_SCSI_RESET follow */
     205             : #define         SG_SCSI_RESET_NOTHING   0
     206             : #define         SG_SCSI_RESET_DEVICE    1
     207             : #define         SG_SCSI_RESET_BUS       2
     208             : #define         SG_SCSI_RESET_HOST      3
     209             : #define         SG_SCSI_RESET_TARGET    4
     210             : 
     211             : /* synchronous SCSI command ioctl, (only in version 3 interface) */
     212             : #define SG_IO 0x2285   /* similar effect as write() followed by read() */
     213             : 
     214             : #define SG_GET_REQUEST_TABLE 0x2286   /* yields table of active requests */
     215             : 
     216             : /* How to treat EINTR during SG_IO ioctl(), only in SG 3.x series */
     217             : #define SG_SET_KEEP_ORPHAN 0x2287 /* 1 -> hold for read(), 0 -> drop (def) */
     218             : #define SG_GET_KEEP_ORPHAN 0x2288
     219             : 
     220             : /* yields scsi midlevel's access_count for this SCSI device */
     221             : #define SG_GET_ACCESS_COUNT 0x2289  
     222             : 
     223             : 
     224             : #define SG_SCATTER_SZ (8 * 4096)
     225             : /* Largest size (in bytes) a single scatter-gather list element can have.
     226             :    The value used by the driver is 'max(SG_SCATTER_SZ, PAGE_SIZE)'.
     227             :    This value should be a power of 2 (and may be rounded up internally).
     228             :    If scatter-gather is not supported by adapter then this value is the
     229             :    largest data block that can be read/written by a single scsi command. */
     230             : 
     231             : #define SG_DEFAULT_RETRIES 0
     232             : 
     233             : /* Defaults, commented if they differ from original sg driver */
     234             : #define SG_DEF_FORCE_LOW_DMA 0  /* was 1 -> memory below 16MB on i386 */
     235             : #define SG_DEF_FORCE_PACK_ID 0
     236             : #define SG_DEF_KEEP_ORPHAN 0
     237             : #define SG_DEF_RESERVED_SIZE SG_SCATTER_SZ /* load time option */
     238             : 
     239             : /* maximum outstanding requests, write() yields EDOM if exceeded */
     240             : #define SG_MAX_QUEUE 16
     241             : 
     242             : #define SG_BIG_BUFF SG_DEF_RESERVED_SIZE    /* for backward compatibility */
     243             : 
     244             : /* Alternate style type names, "..._t" variants preferred */
     245             : typedef struct sg_io_hdr Sg_io_hdr;
     246             : typedef struct sg_io_vec Sg_io_vec;
     247             : typedef struct sg_scsi_id Sg_scsi_id;
     248             : typedef struct sg_req_info Sg_req_info;
     249           1 : 
     250             : 
     251             : /* vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv */
     252             : /*   The older SG interface based on the 'sg_header' structure follows.   */
     253             : /* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ */
     254             : 
     255             : #define SG_MAX_SENSE 16   /* this only applies to the sg_header interface */
     256             : 
     257             : struct sg_header
     258             : {
     259             :     int pack_len;    /* [o] reply_len (ie useless), ignored as input */
     260             :     int reply_len;   /* [i] max length of expected reply (inc. sg_header) */
     261             :     int pack_id;     /* [io] id number of packet (use ints >= 0) */
     262             :     int result;      /* [o] 0==ok, else (+ve) Unix errno (best ignored) */
     263             :     unsigned int twelve_byte:1;
     264             :         /* [i] Force 12 byte command length for group 6 & 7 commands  */
     265             :     unsigned int target_status:5;   /* [o] scsi status from target */
     266             :     unsigned int host_status:8;     /* [o] host status (see "DID" codes) */
     267             :     unsigned int driver_status:8;   /* [o] driver status+suggestion */
     268             :     unsigned int other_flags:10;    /* unused */
     269             :     unsigned char sense_buffer[SG_MAX_SENSE]; /* [o] Output in 3 cases:
     270             :            when target_status is CHECK_CONDITION or
     271             :            when target_status is COMMAND_TERMINATED or
     272             :            when (driver_status & DRIVER_SENSE) is true. */
     273             : };      /* This structure is 36 bytes long on i386 */
     274             : 
     275             : 
     276             : /* IOCTLs: The following are not required (or ignored) when the sg_io_hdr_t
     277             :            interface is used. They are kept for backward compatibility with
     278             :            the original and version 2 drivers. */
     279             : 
     280             : #define SG_SET_TIMEOUT 0x2201  /* unit: jiffies (10ms on i386) */
     281             : #define SG_GET_TIMEOUT 0x2202  /* yield timeout as _return_ value */
     282             : 
     283             : /* Get/set command queuing state per fd (default is SG_DEF_COMMAND_Q.
     284             :    Each time a sg_io_hdr_t object is seen on this file descriptor, this
     285             :    command queuing flag is set on (overriding the previous setting). */
     286             : #define SG_GET_COMMAND_Q 0x2270   /* Yields 0 (queuing off) or 1 (on) */
     287             : #define SG_SET_COMMAND_Q 0x2271   /* Change queuing state with 0 or 1 */
     288             : 
     289             : /* Turn on/off error sense trace (1 and 0 respectively, default is off).
     290             :    Try using: "# cat /proc/scsi/sg/debug" instead in the v3 driver */
     291             : #define SG_SET_DEBUG 0x227e    /* 0 -> turn off debug */
     292             : 
     293             : #define SG_NEXT_CMD_LEN 0x2283  /* override SCSI command length with given
     294             :                    number on the next write() on this file descriptor */
     295             : 
     296             : 
     297             : /* Defaults, commented if they differ from original sg driver */
     298             : #ifdef __KERNEL__
     299             : #define SG_DEFAULT_TIMEOUT_USER (60*USER_HZ) /* HZ == 'jiffies in 1 second' */
     300             : #else
     301             : #define SG_DEFAULT_TIMEOUT      (60*HZ)      /* HZ == 'jiffies in 1 second' */
     302             : #endif
     303             : 
     304             : #define SG_DEF_COMMAND_Q 0     /* command queuing is always on when
     305             :                                   the new interface is used */
     306             : #define SG_DEF_UNDERRUN_FLAG 0
     307             : 
     308             : #endif

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