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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/scsi/sg.h
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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+#ifndef _SCSI_GENERIC_H
+#define _SCSI_GENERIC_H
+
+#include <linux/compiler.h>
+
+/*
+ History:
+ Started: Aug 9 by Lawrence Foard (entropy@world.std.com), to allow user
+ process control of SCSI devices.
+ Development Sponsored by Killy Corp. NY NY
+Original driver (sg.h):
+* Copyright (C) 1992 Lawrence Foard
+Version 2 and 3 extensions to driver:
+* Copyright (C) 1998 - 2003 Douglas Gilbert
+
+ Version: 3.5.29 (20030529)
+ This version is for 2.5 series kernels.
+
+ Changes since 3.5.28 (20030308)
+ - fix bug introduced in version 3.1.24 (last segment of sgat list)
+ Changes since 3.5.27 (20020812)
+ - remove procfs entries: hosts, host_hdr + host_strs (now in sysfs)
+ - add sysfs sg driver params: def_reserved_size, allow_dio, version
+ - new boot option: "sg_allow_dio" and module parameter: "allow_dio"
+ - multiple internal changes due to scsi subsystem rework
+ Changes since 3.5.26 (20020708)
+ - re-add direct IO using Kai Makisara's work
+ - re-tab to 8, start using C99-isms
+ - simplify memory management
+ Changes since 3.5.25 (20020504)
+ - driverfs additions
+ - copy_to/from_user() fixes [William Stinson]
+ - disable kiobufs support
+
+ For a full changelog see http://www.torque.net/sg
+
+Map of SG verions to the Linux kernels in which they appear:
+ ---------- ----------------------------------
+ original all kernels < 2.2.6
+ 2.1.40 2.2.20
+ 3.0.x optional version 3 sg driver for 2.2 series
+ 3.1.17++ 2.4.0++
+ 3.5.23++ 2.5.0++
+
+Major new features in SG 3.x driver (cf SG 2.x drivers)
+ - SG_IO ioctl() combines function if write() and read()
+ - new interface (sg_io_hdr_t) but still supports old interface
+ - scatter/gather in user space, direct IO, and mmap supported
+
+ The normal action of this driver is to use the adapter (HBA) driver to DMA
+ data into kernel buffers and then use the CPU to copy the data into the
+ user space (vice versa for writes). That is called "indirect" IO due to
+ the double handling of data. There are two methods offered to remove the
+ redundant copy: 1) direct IO which uses the kernel kiobuf mechanism and
+ 2) using the mmap() system call to map the reserve buffer (this driver has
+ one reserve buffer per fd) into the user space. Both have their advantages.
+ In terms of absolute speed mmap() is faster. If speed is not a concern,
+ indirect IO should be fine. Read the documentation for more information.
+
+ ** N.B. To use direct IO 'echo 1 > /proc/scsi/sg/allow_dio' may be
+ needed. That pseudo file's content is defaulted to 0. **
+
+ Historical note: this SCSI pass-through driver has been known as "sg" for
+ a decade. In broader kernel discussions "sg" is used to refer to scatter
+ gather techniques. The context should clarify which "sg" is referred to.
+
+ Documentation
+ =============
+ A web site for the SG device driver can be found at:
+ http://www.torque.net/sg [alternatively check the MAINTAINERS file]
+ The documentation for the sg version 3 driver can be found at:
+ http://www.torque.net/sg/p/sg_v3_ho.html
+ This is a rendering from DocBook source [change the extension to "sgml"
+ or "xml"]. There are renderings in "ps", "pdf", "rtf" and "txt" (soon).
+
+ The older, version 2 documents discuss the original sg interface in detail:
+ http://www.torque.net/sg/p/scsi-generic.txt
+ http://www.torque.net/sg/p/scsi-generic_long.txt
+ A version of this document (potentially out of date) may also be found in
+ the kernel source tree, probably at:
+ Documentation/scsi/scsi-generic.txt .
+
+ Utility and test programs are available at the sg web site. They are
+ bundled as sg_utils (for the lk 2.2 series) and sg3_utils (for the
+ lk 2.4 series).
+
+ There is a HOWTO on the Linux SCSI subsystem in the lk 2.4 series at:
+ http://www.linuxdoc.org/HOWTO/SCSI-2.4-HOWTO
+*/
+
+
+/* New interface introduced in the 3.x SG drivers follows */
+
+typedef struct sg_iovec /* same structure as used by readv() Linux system */
+{ /* call. It defines one scatter-gather element. */
+ void __user *iov_base; /* Starting address */
+ size_t iov_len; /* Length in bytes */
+} sg_iovec_t;
+
+
+typedef struct sg_io_hdr
+{
+ int interface_id; /* [i] 'S' for SCSI generic (required) */
+ int dxfer_direction; /* [i] data transfer direction */
+ unsigned char cmd_len; /* [i] SCSI command length ( <= 16 bytes) */
+ unsigned char mx_sb_len; /* [i] max length to write to sbp */
+ unsigned short iovec_count; /* [i] 0 implies no scatter gather */
+ unsigned int dxfer_len; /* [i] byte count of data transfer */
+ void __user *dxferp; /* [i], [*io] points to data transfer memory
+ or scatter gather list */
+ unsigned char __user *cmdp; /* [i], [*i] points to command to perform */
+ void __user *sbp; /* [i], [*o] points to sense_buffer memory */
+ unsigned int timeout; /* [i] MAX_UINT->no timeout (unit: millisec) */
+ unsigned int flags; /* [i] 0 -> default, see SG_FLAG... */
+ int pack_id; /* [i->o] unused internally (normally) */
+ void __user * usr_ptr; /* [i->o] unused internally */
+ unsigned char status; /* [o] scsi status */
+ unsigned char masked_status;/* [o] shifted, masked scsi status */
+ unsigned char msg_status; /* [o] messaging level data (optional) */
+ unsigned char sb_len_wr; /* [o] byte count actually written to sbp */
+ unsigned short host_status; /* [o] errors from host adapter */
+ unsigned short driver_status;/* [o] errors from software driver */
+ int resid; /* [o] dxfer_len - actual_transferred */
+ unsigned int duration; /* [o] time taken by cmd (unit: millisec) */
+ unsigned int info; /* [o] auxiliary information */
+} sg_io_hdr_t; /* 64 bytes long (on i386) */
+
+#define SG_INTERFACE_ID_ORIG 'S'
+
+/* Use negative values to flag difference from original sg_header structure */
+#define SG_DXFER_NONE (-1) /* e.g. a SCSI Test Unit Ready command */
+#define SG_DXFER_TO_DEV (-2) /* e.g. a SCSI WRITE command */
+#define SG_DXFER_FROM_DEV (-3) /* e.g. a SCSI READ command */
+#define SG_DXFER_TO_FROM_DEV (-4) /* treated like SG_DXFER_FROM_DEV with the
+ additional property than during indirect
+ IO the user buffer is copied into the
+ kernel buffers before the transfer */
+#define SG_DXFER_UNKNOWN (-5) /* Unknown data direction */
+
+/* following flag values can be "or"-ed together */
+#define SG_FLAG_DIRECT_IO 1 /* default is indirect IO */
+#define SG_FLAG_UNUSED_LUN_INHIBIT 2 /* default is overwrite lun in SCSI */
+ /* command block (when <= SCSI_2) */
+#define SG_FLAG_MMAP_IO 4 /* request memory mapped IO */
+#define SG_FLAG_NO_DXFER 0x10000 /* no transfer of kernel buffers to/from */
+ /* user space (debug indirect IO) */
+
+/* following 'info' values are "or"-ed together */
+#define SG_INFO_OK_MASK 0x1
+#define SG_INFO_OK 0x0 /* no sense, host nor driver "noise" */
+#define SG_INFO_CHECK 0x1 /* something abnormal happened */
+
+#define SG_INFO_DIRECT_IO_MASK 0x6
+#define SG_INFO_INDIRECT_IO 0x0 /* data xfer via kernel buffers (or no xfer) */
+#define SG_INFO_DIRECT_IO 0x2 /* direct IO requested and performed */
+#define SG_INFO_MIXED_IO 0x4 /* part direct, part indirect IO */
+
+
+typedef struct sg_scsi_id { /* used by SG_GET_SCSI_ID ioctl() */
+ int host_no; /* as in "scsi<n>" where 'n' is one of 0, 1, 2 etc */
+ int channel;
+ int scsi_id; /* scsi id of target device */
+ int lun;
+ int scsi_type; /* TYPE_... defined in scsi/scsi.h */
+ short h_cmd_per_lun;/* host (adapter) maximum commands per lun */
+ short d_queue_depth;/* device (or adapter) maximum queue length */
+ int unused[2]; /* probably find a good use, set 0 for now */
+} sg_scsi_id_t; /* 32 bytes long on i386 */
+
+typedef struct sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */
+ char req_state; /* 0 -> not used, 1 -> written, 2 -> ready to read */
+ char orphan; /* 0 -> normal request, 1 -> from interruped SG_IO */
+ char sg_io_owned; /* 0 -> complete with read(), 1 -> owned by SG_IO */
+ char problem; /* 0 -> no problem detected, 1 -> error to report */
+ int pack_id; /* pack_id associated with request */
+ void __user *usr_ptr; /* user provided pointer (in new interface) */
+ unsigned int duration; /* millisecs elapsed since written (req_state==1)
+ or request duration (req_state==2) */
+ int unused;
+} sg_req_info_t; /* 20 bytes long on i386 */
+
+
+/* IOCTLs: Those ioctls that are relevant to the SG 3.x drivers follow.
+ [Those that only apply to the SG 2.x drivers are at the end of the file.]
+ (_GET_s yield result via 'int *' 3rd argument unless otherwise indicated) */
+
+#define SG_EMULATED_HOST 0x2203 /* true for emulated host adapter (ATAPI) */
+
+/* Used to configure SCSI command transformation layer for ATAPI devices */
+/* Only supported by the ide-scsi driver */
+#define SG_SET_TRANSFORM 0x2204 /* N.B. 3rd arg is not pointer but value: */
+ /* 3rd arg = 0 to disable transform, 1 to enable it */
+#define SG_GET_TRANSFORM 0x2205
+
+#define SG_SET_RESERVED_SIZE 0x2275 /* request a new reserved buffer size */
+#define SG_GET_RESERVED_SIZE 0x2272 /* actual size of reserved buffer */
+
+/* The following ioctl has a 'sg_scsi_id_t *' object as its 3rd argument. */
+#define SG_GET_SCSI_ID 0x2276 /* Yields fd's bus, chan, dev, lun + type */
+/* SCSI id information can also be obtained from SCSI_IOCTL_GET_IDLUN */
+
+/* Override host setting and always DMA using low memory ( <16MB on i386) */
+#define SG_SET_FORCE_LOW_DMA 0x2279 /* 0-> use adapter setting, 1-> force */
+#define SG_GET_LOW_DMA 0x227a /* 0-> use all ram for dma; 1-> low dma ram */
+
+/* When SG_SET_FORCE_PACK_ID set to 1, pack_id is input to read() which
+ tries to fetch a packet with a matching pack_id, waits, or returns EAGAIN.
+ If pack_id is -1 then read oldest waiting. When ...FORCE_PACK_ID set to 0
+ then pack_id ignored by read() and oldest readable fetched. */
+#define SG_SET_FORCE_PACK_ID 0x227b
+#define SG_GET_PACK_ID 0x227c /* Yields oldest readable pack_id (or -1) */
+
+#define SG_GET_NUM_WAITING 0x227d /* Number of commands awaiting read() */
+
+/* Yields max scatter gather tablesize allowed by current host adapter */
+#define SG_GET_SG_TABLESIZE 0x227F /* 0 implies can't do scatter gather */
+
+#define SG_GET_VERSION_NUM 0x2282 /* Example: version 2.1.34 yields 20134 */
+
+/* Returns -EBUSY if occupied. 3rd argument pointer to int (see next) */
+#define SG_SCSI_RESET 0x2284
+/* Associated values that can be given to SG_SCSI_RESET follow */
+#define SG_SCSI_RESET_NOTHING 0
+#define SG_SCSI_RESET_DEVICE 1
+#define SG_SCSI_RESET_BUS 2
+#define SG_SCSI_RESET_HOST 3
+
+/* synchronous SCSI command ioctl, (only in version 3 interface) */
+#define SG_IO 0x2285 /* similar effect as write() followed by read() */
+
+#define SG_GET_REQUEST_TABLE 0x2286 /* yields table of active requests */
+
+/* How to treat EINTR during SG_IO ioctl(), only in SG 3.x series */
+#define SG_SET_KEEP_ORPHAN 0x2287 /* 1 -> hold for read(), 0 -> drop (def) */
+#define SG_GET_KEEP_ORPHAN 0x2288
+
+/* yields scsi midlevel's access_count for this SCSI device */
+#define SG_GET_ACCESS_COUNT 0x2289
+
+
+#define SG_SCATTER_SZ (8 * 4096) /* PAGE_SIZE not available to user */
+/* Largest size (in bytes) a single scatter-gather list element can have.
+ The value must be a power of 2 and <= (PAGE_SIZE * 32) [131072 bytes on
+ i386]. The minimum value is PAGE_SIZE. If scatter-gather not supported
+ by adapter then this value is the largest data block that can be
+ read/written by a single scsi command. The user can find the value of
+ PAGE_SIZE by calling getpagesize() defined in unistd.h . */
+
+#define SG_DEFAULT_RETRIES 0
+
+/* Defaults, commented if they differ from original sg driver */
+#define SG_DEF_FORCE_LOW_DMA 0 /* was 1 -> memory below 16MB on i386 */
+#define SG_DEF_FORCE_PACK_ID 0
+#define SG_DEF_KEEP_ORPHAN 0
+#define SG_DEF_RESERVED_SIZE SG_SCATTER_SZ /* load time option */
+
+/* maximum outstanding requests, write() yields EDOM if exceeded */
+#define SG_MAX_QUEUE 16
+
+#define SG_BIG_BUFF SG_DEF_RESERVED_SIZE /* for backward compatibility */
+
+/* Alternate style type names, "..._t" variants preferred */
+typedef struct sg_io_hdr Sg_io_hdr;
+typedef struct sg_io_vec Sg_io_vec;
+typedef struct sg_scsi_id Sg_scsi_id;
+typedef struct sg_req_info Sg_req_info;
+
+
+/* vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv */
+/* The older SG interface based on the 'sg_header' structure follows. */
+/* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ */
+
+#define SG_MAX_SENSE 16 /* this only applies to the sg_header interface */
+
+struct sg_header
+{
+ int pack_len; /* [o] reply_len (ie useless), ignored as input */
+ int reply_len; /* [i] max length of expected reply (inc. sg_header) */
+ int pack_id; /* [io] id number of packet (use ints >= 0) */
+ int result; /* [o] 0==ok, else (+ve) Unix errno (best ignored) */
+ unsigned int twelve_byte:1;
+ /* [i] Force 12 byte command length for group 6 & 7 commands */
+ unsigned int target_status:5; /* [o] scsi status from target */
+ unsigned int host_status:8; /* [o] host status (see "DID" codes) */
+ unsigned int driver_status:8; /* [o] driver status+suggestion */
+ unsigned int other_flags:10; /* unused */
+ unsigned char sense_buffer[SG_MAX_SENSE]; /* [o] Output in 3 cases:
+ when target_status is CHECK_CONDITION or
+ when target_status is COMMAND_TERMINATED or
+ when (driver_status & DRIVER_SENSE) is true. */
+}; /* This structure is 36 bytes long on i386 */
+
+
+/* IOCTLs: The following are not required (or ignored) when the sg_io_hdr_t
+ interface is used. They are kept for backward compatibility with
+ the original and version 2 drivers. */
+
+#define SG_SET_TIMEOUT 0x2201 /* unit: jiffies (10ms on i386) */
+#define SG_GET_TIMEOUT 0x2202 /* yield timeout as _return_ value */
+
+/* Get/set command queuing state per fd (default is SG_DEF_COMMAND_Q.
+ Each time a sg_io_hdr_t object is seen on this file descriptor, this
+ command queuing flag is set on (overriding the previous setting). */
+#define SG_GET_COMMAND_Q 0x2270 /* Yields 0 (queuing off) or 1 (on) */
+#define SG_SET_COMMAND_Q 0x2271 /* Change queuing state with 0 or 1 */
+
+/* Turn on/off error sense trace (1 and 0 respectively, default is off).
+ Try using: "# cat /proc/scsi/sg/debug" instead in the v3 driver */
+#define SG_SET_DEBUG 0x227e /* 0 -> turn off debug */
+
+#define SG_NEXT_CMD_LEN 0x2283 /* override SCSI command length with given
+ number on the next write() on this file descriptor */
+
+
+/* Defaults, commented if they differ from original sg driver */
+#ifdef __KERNEL__
+#define SG_DEFAULT_TIMEOUT_USER (60*USER_HZ) /* HZ == 'jiffies in 1 second' */
+#else
+#define SG_DEFAULT_TIMEOUT (60*HZ) /* HZ == 'jiffies in 1 second' */
+#endif
+
+#define SG_DEF_COMMAND_Q 0 /* command queuing is always on when
+ the new interface is used */
+#define SG_DEF_UNDERRUN_FLAG 0
+
+#endif

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