327 lines
15 KiB
C
327 lines
15 KiB
C
|
#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
|