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Diffstat (limited to 'include/scsi/sg.h')
| -rw-r--r-- | include/scsi/sg.h | 326 |
1 files changed, 326 insertions, 0 deletions
diff --git a/include/scsi/sg.h b/include/scsi/sg.h new file mode 100644 index 0000000..0a487fe --- /dev/null +++ b/include/scsi/sg.h @@ -0,0 +1,326 @@ +#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 |
