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 #ifdef __KERNEL__ 74 extern int sg_big_buff; /* for sysctl */ 75 #endif 76 77 /* New interface introduced in the 3.x SG drivers follows */ 78 79 typedef struct sg_iovec /* same structure as used by readv() Linux system */ 80 { /* call. It defines one scatter-gather element. */ 81 void __user *iov_base; /* Starting address */ 82 size_t iov_len; /* Length in bytes */ 83 } sg_iovec_t; 84 85 86 typedef struct sg_io_hdr 87 { 88 int interface_id; /* [i] 'S' for SCSI generic (required) */ 89 int dxfer_direction; /* [i] data transfer direction */ 90 unsigned char cmd_len; /* [i] SCSI command length ( <= 16 bytes) */ 91 unsigned char mx_sb_len; /* [i] max length to write to sbp */ 92 unsigned short iovec_count; /* [i] 0 implies no scatter gather */ 93 unsigned int dxfer_len; /* [i] byte count of data transfer */ 94 void __user *dxferp; /* [i], [*io] points to data transfer memory 95 or scatter gather list */ 96 unsigned char __user *cmdp; /* [i], [*i] points to command to perform */ 97 void __user *sbp; /* [i], [*o] points to sense_buffer memory */ 98 unsigned int timeout; /* [i] MAX_UINT->no timeout (unit: millisec) */ 99 unsigned int flags; /* [i] 0 -> default, see SG_FLAG... */ 100 int pack_id; /* [i->o] unused internally (normally) */ 101 void __user * usr_ptr; /* [i->o] unused internally */ 102 unsigned char status; /* [o] scsi status */ 103 unsigned char masked_status;/* [o] shifted, masked scsi status */ 104 unsigned char msg_status; /* [o] messaging level data (optional) */ 105 unsigned char sb_len_wr; /* [o] byte count actually written to sbp */ 106 unsigned short host_status; /* [o] errors from host adapter */ 107 unsigned short driver_status;/* [o] errors from software driver */ 108 int resid; /* [o] dxfer_len - actual_transferred */ 109 unsigned int duration; /* [o] time taken by cmd (unit: millisec) */ 110 unsigned int info; /* [o] auxiliary information */ 111 } sg_io_hdr_t; /* 64 bytes long (on i386) */ 112 113 #define SG_INTERFACE_ID_ORIG 'S' 114 115 /* Use negative values to flag difference from original sg_header structure */ 116 #define SG_DXFER_NONE (-1) /* e.g. a SCSI Test Unit Ready command */ 117 #define SG_DXFER_TO_DEV (-2) /* e.g. a SCSI WRITE command */ 118 #define SG_DXFER_FROM_DEV (-3) /* e.g. a SCSI READ command */ 119 #define SG_DXFER_TO_FROM_DEV (-4) /* treated like SG_DXFER_FROM_DEV with the 120 additional property than during indirect 121 IO the user buffer is copied into the 122 kernel buffers before the transfer */ 123 #define SG_DXFER_UNKNOWN (-5) /* Unknown data direction */ 124 125 /* following flag values can be "or"-ed together */ 126 #define SG_FLAG_DIRECT_IO 1 /* default is indirect IO */ 127 #define SG_FLAG_UNUSED_LUN_INHIBIT 2 /* default is overwrite lun in SCSI */ 128 /* command block (when <= SCSI_2) */ 129 #define SG_FLAG_MMAP_IO 4 /* request memory mapped IO */ 130 #define SG_FLAG_NO_DXFER 0x10000 /* no transfer of kernel buffers to/from */ 131 /* user space (debug indirect IO) */ 132 133 /* following 'info' values are "or"-ed together */ 134 #define SG_INFO_OK_MASK 0x1 135 #define SG_INFO_OK 0x0 /* no sense, host nor driver "noise" */ 136 #define SG_INFO_CHECK 0x1 /* something abnormal happened */ 137 138 #define SG_INFO_DIRECT_IO_MASK 0x6 139 #define SG_INFO_INDIRECT_IO 0x0 /* data xfer via kernel buffers (or no xfer) */ 140 #define SG_INFO_DIRECT_IO 0x2 /* direct IO requested and performed */ 141 #define SG_INFO_MIXED_IO 0x4 /* part direct, part indirect IO */ 142 143 144 typedef struct sg_scsi_id { /* used by SG_GET_SCSI_ID ioctl() */ 145 int host_no; /* as in "scsi<n>" where 'n' is one of 0, 1, 2 etc */ 146 int channel; 147 int scsi_id; /* scsi id of target device */ 148 int lun; 149 int scsi_type; /* TYPE_... defined in scsi/scsi.h */ 150 short h_cmd_per_lun;/* host (adapter) maximum commands per lun */ 151 short d_queue_depth;/* device (or adapter) maximum queue length */ 152 int unused[2]; /* probably find a good use, set 0 for now */ 153 } sg_scsi_id_t; /* 32 bytes long on i386 */ 154 155 typedef struct sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */ 156 char req_state; /* 0 -> not used, 1 -> written, 2 -> ready to read */ 157 char orphan; /* 0 -> normal request, 1 -> from interruped SG_IO */ 158 char sg_io_owned; /* 0 -> complete with read(), 1 -> owned by SG_IO */ 159 char problem; /* 0 -> no problem detected, 1 -> error to report */ 160 int pack_id; /* pack_id associated with request */ 161 void __user *usr_ptr; /* user provided pointer (in new interface) */ 162 unsigned int duration; /* millisecs elapsed since written (req_state==1) 163 or request duration (req_state==2) */ 164 int unused; 165 } sg_req_info_t; /* 20 bytes long on i386 */ 166 167 168 /* IOCTLs: Those ioctls that are relevant to the SG 3.x drivers follow. 169 [Those that only apply to the SG 2.x drivers are at the end of the file.] 170 (_GET_s yield result via 'int *' 3rd argument unless otherwise indicated) */ 171 172 #define SG_EMULATED_HOST 0x2203 /* true for emulated host adapter (ATAPI) */ 173 174 /* Used to configure SCSI command transformation layer for ATAPI devices */ 175 /* Only supported by the ide-scsi driver */ 176 #define SG_SET_TRANSFORM 0x2204 /* N.B. 3rd arg is not pointer but value: */ 177 /* 3rd arg = 0 to disable transform, 1 to enable it */ 178 #define SG_GET_TRANSFORM 0x2205 179 180 #define SG_SET_RESERVED_SIZE 0x2275 /* request a new reserved buffer size */ 181 #define SG_GET_RESERVED_SIZE 0x2272 /* actual size of reserved buffer */ 182 183 /* The following ioctl has a 'sg_scsi_id_t *' object as its 3rd argument. */ 184 #define SG_GET_SCSI_ID 0x2276 /* Yields fd's bus, chan, dev, lun + type */ 185 /* SCSI id information can also be obtained from SCSI_IOCTL_GET_IDLUN */ 186 187 /* Override host setting and always DMA using low memory ( <16MB on i386) */ 188 #define SG_SET_FORCE_LOW_DMA 0x2279 /* 0-> use adapter setting, 1-> force */ 189 #define SG_GET_LOW_DMA 0x227a /* 0-> use all ram for dma; 1-> low dma ram */ 190 191 /* When SG_SET_FORCE_PACK_ID set to 1, pack_id is input to read() which 192 tries to fetch a packet with a matching pack_id, waits, or returns EAGAIN. 193 If pack_id is -1 then read oldest waiting. When ...FORCE_PACK_ID set to 0 194 then pack_id ignored by read() and oldest readable fetched. */ 195 #define SG_SET_FORCE_PACK_ID 0x227b 196 #define SG_GET_PACK_ID 0x227c /* Yields oldest readable pack_id (or -1) */ 197 198 #define SG_GET_NUM_WAITING 0x227d /* Number of commands awaiting read() */ 199 200 /* Yields max scatter gather tablesize allowed by current host adapter */ 201 #define SG_GET_SG_TABLESIZE 0x227F /* 0 implies can't do scatter gather */ 202 203 #define SG_GET_VERSION_NUM 0x2282 /* Example: version 2.1.34 yields 20134 */ 204 205 /* Returns -EBUSY if occupied. 3rd argument pointer to int (see next) */ 206 #define SG_SCSI_RESET 0x2284 207 /* Associated values that can be given to SG_SCSI_RESET follow */ 208 #define SG_SCSI_RESET_NOTHING 0 209 #define SG_SCSI_RESET_DEVICE 1 210 #define SG_SCSI_RESET_BUS 2 211 #define SG_SCSI_RESET_HOST 3 212 #define SG_SCSI_RESET_TARGET 4 213 214 /* synchronous SCSI command ioctl, (only in version 3 interface) */ 215 #define SG_IO 0x2285 /* similar effect as write() followed by read() */ 216 217 #define SG_GET_REQUEST_TABLE 0x2286 /* yields table of active requests */ 218 219 /* How to treat EINTR during SG_IO ioctl(), only in SG 3.x series */ 220 #define SG_SET_KEEP_ORPHAN 0x2287 /* 1 -> hold for read(), 0 -> drop (def) */ 221 #define SG_GET_KEEP_ORPHAN 0x2288 222 223 /* yields scsi midlevel's access_count for this SCSI device */ 224 #define SG_GET_ACCESS_COUNT 0x2289 225 226 227 #define SG_SCATTER_SZ (8 * 4096) 228 /* Largest size (in bytes) a single scatter-gather list element can have. 229 The value used by the driver is 'max(SG_SCATTER_SZ, PAGE_SIZE)'. 230 This value should be a power of 2 (and may be rounded up internally). 231 If scatter-gather is not supported by adapter then this value is the 232 largest data block that can be read/written by a single scsi command. */ 233 234 #define SG_DEFAULT_RETRIES 0 235 236 /* Defaults, commented if they differ from original sg driver */ 237 #define SG_DEF_FORCE_LOW_DMA 0 /* was 1 -> memory below 16MB on i386 */ 238 #define SG_DEF_FORCE_PACK_ID 0 239 #define SG_DEF_KEEP_ORPHAN 0 240 #define SG_DEF_RESERVED_SIZE SG_SCATTER_SZ /* load time option */ 241 242 /* maximum outstanding requests, write() yields EDOM if exceeded */ 243 #define SG_MAX_QUEUE 16 244 245 #define SG_BIG_BUFF SG_DEF_RESERVED_SIZE /* for backward compatibility */ 246 247 /* Alternate style type names, "..._t" variants preferred */ 248 typedef struct sg_io_hdr Sg_io_hdr; 249 typedef struct sg_io_vec Sg_io_vec; 250 typedef struct sg_scsi_id Sg_scsi_id; 251 typedef struct sg_req_info Sg_req_info; 252 253 254 /* vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv */ 255 /* The older SG interface based on the 'sg_header' structure follows. */ 256 /* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ */ 257 258 #define SG_MAX_SENSE 16 /* this only applies to the sg_header interface */ 259 260 struct sg_header 261 { 262 int pack_len; /* [o] reply_len (ie useless), ignored as input */ 263 int reply_len; /* [i] max length of expected reply (inc. sg_header) */ 264 int pack_id; /* [io] id number of packet (use ints >= 0) */ 265 int result; /* [o] 0==ok, else (+ve) Unix errno (best ignored) */ 266 unsigned int twelve_byte:1; 267 /* [i] Force 12 byte command length for group 6 & 7 commands */ 268 unsigned int target_status:5; /* [o] scsi status from target */ 269 unsigned int host_status:8; /* [o] host status (see "DID" codes) */ 270 unsigned int driver_status:8; /* [o] driver status+suggestion */ 271 unsigned int other_flags:10; /* unused */ 272 unsigned char sense_buffer[SG_MAX_SENSE]; /* [o] Output in 3 cases: 273 when target_status is CHECK_CONDITION or 274 when target_status is COMMAND_TERMINATED or 275 when (driver_status & DRIVER_SENSE) is true. */ 276 }; /* This structure is 36 bytes long on i386 */ 277 278 279 /* IOCTLs: The following are not required (or ignored) when the sg_io_hdr_t 280 interface is used. They are kept for backward compatibility with 281 the original and version 2 drivers. */ 282 283 #define SG_SET_TIMEOUT 0x2201 /* unit: jiffies (10ms on i386) */ 284 #define SG_GET_TIMEOUT 0x2202 /* yield timeout as _return_ value */ 285 286 /* Get/set command queuing state per fd (default is SG_DEF_COMMAND_Q. 287 Each time a sg_io_hdr_t object is seen on this file descriptor, this 288 command queuing flag is set on (overriding the previous setting). */ 289 #define SG_GET_COMMAND_Q 0x2270 /* Yields 0 (queuing off) or 1 (on) */ 290 #define SG_SET_COMMAND_Q 0x2271 /* Change queuing state with 0 or 1 */ 291 292 /* Turn on/off error sense trace (1 and 0 respectively, default is off). 293 Try using: "# cat /proc/scsi/sg/debug" instead in the v3 driver */ 294 #define SG_SET_DEBUG 0x227e /* 0 -> turn off debug */ 295 296 #define SG_NEXT_CMD_LEN 0x2283 /* override SCSI command length with given 297 number on the next write() on this file descriptor */ 298 299 300 /* Defaults, commented if they differ from original sg driver */ 301 #ifdef __KERNEL__ 302 #define SG_DEFAULT_TIMEOUT_USER (60*USER_HZ) /* HZ == 'jiffies in 1 second' */ 303 #else 304 #define SG_DEFAULT_TIMEOUT (60*HZ) /* HZ == 'jiffies in 1 second' */ 305 #endif 306 307 #define SG_DEF_COMMAND_Q 0 /* command queuing is always on when 308 the new interface is used */ 309 #define SG_DEF_UNDERRUN_FLAG 0 310 311 #endif 312