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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