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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 - 2003 Douglas Gilbert | |
15 | ||
16 | Version: 3.5.29 (20030529) | |
17 | This version is for 2.5 series kernels. | |
18 | ||
19 | Changes since 3.5.28 (20030308) | |
20 | - fix bug introduced in version 3.1.24 (last segment of sgat list) | |
21 | Changes since 3.5.27 (20020812) | |
22 | - remove procfs entries: hosts, host_hdr + host_strs (now in sysfs) | |
23 | - add sysfs sg driver params: def_reserved_size, allow_dio, version | |
24 | - new boot option: "sg_allow_dio" and module parameter: "allow_dio" | |
25 | - multiple internal changes due to scsi subsystem rework | |
26 | Changes since 3.5.26 (20020708) | |
27 | - re-add direct IO using Kai Makisara's work | |
28 | - re-tab to 8, start using C99-isms | |
29 | - simplify memory management | |
30 | Changes since 3.5.25 (20020504) | |
31 | - driverfs additions | |
32 | - copy_to/from_user() fixes [William Stinson] | |
33 | - disable kiobufs support | |
34 | ||
35 | For a full changelog see http://www.torque.net/sg | |
36 | ||
37 | Map of SG verions to the Linux kernels in which they appear: | |
38 | ---------- ---------------------------------- | |
39 | original all kernels < 2.2.6 | |
40 | 2.1.40 2.2.20 | |
41 | 3.0.x optional version 3 sg driver for 2.2 series | |
42 | 3.1.17++ 2.4.0++ | |
43 | 3.5.23++ 2.5.0++ | |
44 | ||
45 | Major new features in SG 3.x driver (cf SG 2.x drivers) | |
46 | - SG_IO ioctl() combines function if write() and read() | |
47 | - new interface (sg_io_hdr_t) but still supports old interface | |
48 | - scatter/gather in user space, direct IO, and mmap supported | |
49 | ||
50 | The normal action of this driver is to use the adapter (HBA) driver to DMA | |
51 | data into kernel buffers and then use the CPU to copy the data into the | |
52 | user space (vice versa for writes). That is called "indirect" IO due to | |
53 | the double handling of data. There are two methods offered to remove the | |
54 | redundant copy: 1) direct IO which uses the kernel kiobuf mechanism and | |
55 | 2) using the mmap() system call to map the reserve buffer (this driver has | |
56 | one reserve buffer per fd) into the user space. Both have their advantages. | |
57 | In terms of absolute speed mmap() is faster. If speed is not a concern, | |
58 | indirect IO should be fine. Read the documentation for more information. | |
59 | ||
60 | ** N.B. To use direct IO 'echo 1 > /proc/scsi/sg/allow_dio' may be | |
61 | needed. That pseudo file's content is defaulted to 0. ** | |
62 | ||
63 | Historical note: this SCSI pass-through driver has been known as "sg" for | |
64 | a decade. In broader kernel discussions "sg" is used to refer to scatter | |
65 | gather techniques. The context should clarify which "sg" is referred to. | |
66 | ||
67 | Documentation | |
68 | ============= | |
69 | A web site for the SG device driver can be found at: | |
70 | http://www.torque.net/sg [alternatively check the MAINTAINERS file] | |
71 | The documentation for the sg version 3 driver can be found at: | |
72 | http://www.torque.net/sg/p/sg_v3_ho.html | |
73 | This is a rendering from DocBook source [change the extension to "sgml" | |
74 | or "xml"]. There are renderings in "ps", "pdf", "rtf" and "txt" (soon). | |
75 | ||
76 | The older, version 2 documents discuss the original sg interface in detail: | |
77 | http://www.torque.net/sg/p/scsi-generic.txt | |
78 | http://www.torque.net/sg/p/scsi-generic_long.txt | |
79 | A version of this document (potentially out of date) may also be found in | |
80 | the kernel source tree, probably at: | |
81 | Documentation/scsi/scsi-generic.txt . | |
82 | ||
83 | Utility and test programs are available at the sg web site. They are | |
84 | bundled as sg_utils (for the lk 2.2 series) and sg3_utils (for the | |
85 | lk 2.4 series). | |
86 | ||
87 | There is a HOWTO on the Linux SCSI subsystem in the lk 2.4 series at: | |
88 | http://www.linuxdoc.org/HOWTO/SCSI-2.4-HOWTO | |
89 | */ | |
90 | ||
91 | ||
92 | /* New interface introduced in the 3.x SG drivers follows */ | |
93 | ||
94 | typedef struct sg_iovec /* same structure as used by readv() Linux system */ | |
95 | { /* call. It defines one scatter-gather element. */ | |
96 | void __user *iov_base; /* Starting address */ | |
97 | size_t iov_len; /* Length in bytes */ | |
98 | } sg_iovec_t; | |
99 | ||
100 | ||
101 | typedef struct sg_io_hdr | |
102 | { | |
103 | int interface_id; /* [i] 'S' for SCSI generic (required) */ | |
104 | int dxfer_direction; /* [i] data transfer direction */ | |
105 | unsigned char cmd_len; /* [i] SCSI command length ( <= 16 bytes) */ | |
106 | unsigned char mx_sb_len; /* [i] max length to write to sbp */ | |
107 | unsigned short iovec_count; /* [i] 0 implies no scatter gather */ | |
108 | unsigned int dxfer_len; /* [i] byte count of data transfer */ | |
109 | void __user *dxferp; /* [i], [*io] points to data transfer memory | |
110 | or scatter gather list */ | |
111 | unsigned char __user *cmdp; /* [i], [*i] points to command to perform */ | |
112 | void __user *sbp; /* [i], [*o] points to sense_buffer memory */ | |
113 | unsigned int timeout; /* [i] MAX_UINT->no timeout (unit: millisec) */ | |
114 | unsigned int flags; /* [i] 0 -> default, see SG_FLAG... */ | |
115 | int pack_id; /* [i->o] unused internally (normally) */ | |
116 | void __user * usr_ptr; /* [i->o] unused internally */ | |
117 | unsigned char status; /* [o] scsi status */ | |
118 | unsigned char masked_status;/* [o] shifted, masked scsi status */ | |
119 | unsigned char msg_status; /* [o] messaging level data (optional) */ | |
120 | unsigned char sb_len_wr; /* [o] byte count actually written to sbp */ | |
121 | unsigned short host_status; /* [o] errors from host adapter */ | |
122 | unsigned short driver_status;/* [o] errors from software driver */ | |
123 | int resid; /* [o] dxfer_len - actual_transferred */ | |
124 | unsigned int duration; /* [o] time taken by cmd (unit: millisec) */ | |
125 | unsigned int info; /* [o] auxiliary information */ | |
126 | } sg_io_hdr_t; /* 64 bytes long (on i386) */ | |
127 | ||
128 | #define SG_INTERFACE_ID_ORIG 'S' | |
129 | ||
130 | /* Use negative values to flag difference from original sg_header structure */ | |
131 | #define SG_DXFER_NONE (-1) /* e.g. a SCSI Test Unit Ready command */ | |
132 | #define SG_DXFER_TO_DEV (-2) /* e.g. a SCSI WRITE command */ | |
133 | #define SG_DXFER_FROM_DEV (-3) /* e.g. a SCSI READ command */ | |
134 | #define SG_DXFER_TO_FROM_DEV (-4) /* treated like SG_DXFER_FROM_DEV with the | |
135 | additional property than during indirect | |
136 | IO the user buffer is copied into the | |
137 | kernel buffers before the transfer */ | |
138 | #define SG_DXFER_UNKNOWN (-5) /* Unknown data direction */ | |
139 | ||
140 | /* following flag values can be "or"-ed together */ | |
141 | #define SG_FLAG_DIRECT_IO 1 /* default is indirect IO */ | |
142 | #define SG_FLAG_UNUSED_LUN_INHIBIT 2 /* default is overwrite lun in SCSI */ | |
143 | /* command block (when <= SCSI_2) */ | |
144 | #define SG_FLAG_MMAP_IO 4 /* request memory mapped IO */ | |
145 | #define SG_FLAG_NO_DXFER 0x10000 /* no transfer of kernel buffers to/from */ | |
146 | /* user space (debug indirect IO) */ | |
147 | ||
148 | /* following 'info' values are "or"-ed together */ | |
149 | #define SG_INFO_OK_MASK 0x1 | |
150 | #define SG_INFO_OK 0x0 /* no sense, host nor driver "noise" */ | |
151 | #define SG_INFO_CHECK 0x1 /* something abnormal happened */ | |
152 | ||
153 | #define SG_INFO_DIRECT_IO_MASK 0x6 | |
154 | #define SG_INFO_INDIRECT_IO 0x0 /* data xfer via kernel buffers (or no xfer) */ | |
155 | #define SG_INFO_DIRECT_IO 0x2 /* direct IO requested and performed */ | |
156 | #define SG_INFO_MIXED_IO 0x4 /* part direct, part indirect IO */ | |
157 | ||
158 | ||
159 | typedef struct sg_scsi_id { /* used by SG_GET_SCSI_ID ioctl() */ | |
160 | int host_no; /* as in "scsi<n>" where 'n' is one of 0, 1, 2 etc */ | |
161 | int channel; | |
162 | int scsi_id; /* scsi id of target device */ | |
163 | int lun; | |
164 | int scsi_type; /* TYPE_... defined in scsi/scsi.h */ | |
165 | short h_cmd_per_lun;/* host (adapter) maximum commands per lun */ | |
166 | short d_queue_depth;/* device (or adapter) maximum queue length */ | |
167 | int unused[2]; /* probably find a good use, set 0 for now */ | |
168 | } sg_scsi_id_t; /* 32 bytes long on i386 */ | |
169 | ||
170 | typedef struct sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */ | |
171 | char req_state; /* 0 -> not used, 1 -> written, 2 -> ready to read */ | |
172 | char orphan; /* 0 -> normal request, 1 -> from interruped SG_IO */ | |
173 | char sg_io_owned; /* 0 -> complete with read(), 1 -> owned by SG_IO */ | |
174 | char problem; /* 0 -> no problem detected, 1 -> error to report */ | |
175 | int pack_id; /* pack_id associated with request */ | |
176 | void __user *usr_ptr; /* user provided pointer (in new interface) */ | |
177 | unsigned int duration; /* millisecs elapsed since written (req_state==1) | |
178 | or request duration (req_state==2) */ | |
179 | int unused; | |
180 | } sg_req_info_t; /* 20 bytes long on i386 */ | |
181 | ||
182 | ||
183 | /* IOCTLs: Those ioctls that are relevant to the SG 3.x drivers follow. | |
184 | [Those that only apply to the SG 2.x drivers are at the end of the file.] | |
185 | (_GET_s yield result via 'int *' 3rd argument unless otherwise indicated) */ | |
186 | ||
187 | #define SG_EMULATED_HOST 0x2203 /* true for emulated host adapter (ATAPI) */ | |
188 | ||
189 | /* Used to configure SCSI command transformation layer for ATAPI devices */ | |
190 | /* Only supported by the ide-scsi driver */ | |
191 | #define SG_SET_TRANSFORM 0x2204 /* N.B. 3rd arg is not pointer but value: */ | |
192 | /* 3rd arg = 0 to disable transform, 1 to enable it */ | |
193 | #define SG_GET_TRANSFORM 0x2205 | |
194 | ||
195 | #define SG_SET_RESERVED_SIZE 0x2275 /* request a new reserved buffer size */ | |
196 | #define SG_GET_RESERVED_SIZE 0x2272 /* actual size of reserved buffer */ | |
197 | ||
198 | /* The following ioctl has a 'sg_scsi_id_t *' object as its 3rd argument. */ | |
199 | #define SG_GET_SCSI_ID 0x2276 /* Yields fd's bus, chan, dev, lun + type */ | |
200 | /* SCSI id information can also be obtained from SCSI_IOCTL_GET_IDLUN */ | |
201 | ||
202 | /* Override host setting and always DMA using low memory ( <16MB on i386) */ | |
203 | #define SG_SET_FORCE_LOW_DMA 0x2279 /* 0-> use adapter setting, 1-> force */ | |
204 | #define SG_GET_LOW_DMA 0x227a /* 0-> use all ram for dma; 1-> low dma ram */ | |
205 | ||
206 | /* When SG_SET_FORCE_PACK_ID set to 1, pack_id is input to read() which | |
207 | tries to fetch a packet with a matching pack_id, waits, or returns EAGAIN. | |
208 | If pack_id is -1 then read oldest waiting. When ...FORCE_PACK_ID set to 0 | |
209 | then pack_id ignored by read() and oldest readable fetched. */ | |
210 | #define SG_SET_FORCE_PACK_ID 0x227b | |
211 | #define SG_GET_PACK_ID 0x227c /* Yields oldest readable pack_id (or -1) */ | |
212 | ||
213 | #define SG_GET_NUM_WAITING 0x227d /* Number of commands awaiting read() */ | |
214 | ||
215 | /* Yields max scatter gather tablesize allowed by current host adapter */ | |
216 | #define SG_GET_SG_TABLESIZE 0x227F /* 0 implies can't do scatter gather */ | |
217 | ||
218 | #define SG_GET_VERSION_NUM 0x2282 /* Example: version 2.1.34 yields 20134 */ | |
219 | ||
220 | /* Returns -EBUSY if occupied. 3rd argument pointer to int (see next) */ | |
221 | #define SG_SCSI_RESET 0x2284 | |
222 | /* Associated values that can be given to SG_SCSI_RESET follow */ | |
223 | #define SG_SCSI_RESET_NOTHING 0 | |
224 | #define SG_SCSI_RESET_DEVICE 1 | |
225 | #define SG_SCSI_RESET_BUS 2 | |
226 | #define SG_SCSI_RESET_HOST 3 | |
227 | ||
228 | /* synchronous SCSI command ioctl, (only in version 3 interface) */ | |
229 | #define SG_IO 0x2285 /* similar effect as write() followed by read() */ | |
230 | ||
231 | #define SG_GET_REQUEST_TABLE 0x2286 /* yields table of active requests */ | |
232 | ||
233 | /* How to treat EINTR during SG_IO ioctl(), only in SG 3.x series */ | |
234 | #define SG_SET_KEEP_ORPHAN 0x2287 /* 1 -> hold for read(), 0 -> drop (def) */ | |
235 | #define SG_GET_KEEP_ORPHAN 0x2288 | |
236 | ||
237 | /* yields scsi midlevel's access_count for this SCSI device */ | |
238 | #define SG_GET_ACCESS_COUNT 0x2289 | |
239 | ||
240 | ||
241 | #define SG_SCATTER_SZ (8 * 4096) /* PAGE_SIZE not available to user */ | |
242 | /* Largest size (in bytes) a single scatter-gather list element can have. | |
243 | The value must be a power of 2 and <= (PAGE_SIZE * 32) [131072 bytes on | |
244 | i386]. The minimum value is PAGE_SIZE. If scatter-gather not supported | |
245 | by adapter then this value is the largest data block that can be | |
246 | read/written by a single scsi command. The user can find the value of | |
247 | PAGE_SIZE by calling getpagesize() defined in unistd.h . */ | |
248 | ||
249 | #define SG_DEFAULT_RETRIES 0 | |
250 | ||
251 | /* Defaults, commented if they differ from original sg driver */ | |
252 | #define SG_DEF_FORCE_LOW_DMA 0 /* was 1 -> memory below 16MB on i386 */ | |
253 | #define SG_DEF_FORCE_PACK_ID 0 | |
254 | #define SG_DEF_KEEP_ORPHAN 0 | |
255 | #define SG_DEF_RESERVED_SIZE SG_SCATTER_SZ /* load time option */ | |
256 | ||
257 | /* maximum outstanding requests, write() yields EDOM if exceeded */ | |
258 | #define SG_MAX_QUEUE 16 | |
259 | ||
260 | #define SG_BIG_BUFF SG_DEF_RESERVED_SIZE /* for backward compatibility */ | |
261 | ||
262 | /* Alternate style type names, "..._t" variants preferred */ | |
263 | typedef struct sg_io_hdr Sg_io_hdr; | |
264 | typedef struct sg_io_vec Sg_io_vec; | |
265 | typedef struct sg_scsi_id Sg_scsi_id; | |
266 | typedef struct sg_req_info Sg_req_info; | |
267 | ||
268 | ||
269 | /* vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv */ | |
270 | /* The older SG interface based on the 'sg_header' structure follows. */ | |
271 | /* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ */ | |
272 | ||
273 | #define SG_MAX_SENSE 16 /* this only applies to the sg_header interface */ | |
274 | ||
275 | struct sg_header | |
276 | { | |
277 | int pack_len; /* [o] reply_len (ie useless), ignored as input */ | |
278 | int reply_len; /* [i] max length of expected reply (inc. sg_header) */ | |
279 | int pack_id; /* [io] id number of packet (use ints >= 0) */ | |
280 | int result; /* [o] 0==ok, else (+ve) Unix errno (best ignored) */ | |
281 | unsigned int twelve_byte:1; | |
282 | /* [i] Force 12 byte command length for group 6 & 7 commands */ | |
283 | unsigned int target_status:5; /* [o] scsi status from target */ | |
284 | unsigned int host_status:8; /* [o] host status (see "DID" codes) */ | |
285 | unsigned int driver_status:8; /* [o] driver status+suggestion */ | |
286 | unsigned int other_flags:10; /* unused */ | |
287 | unsigned char sense_buffer[SG_MAX_SENSE]; /* [o] Output in 3 cases: | |
288 | when target_status is CHECK_CONDITION or | |
289 | when target_status is COMMAND_TERMINATED or | |
290 | when (driver_status & DRIVER_SENSE) is true. */ | |
291 | }; /* This structure is 36 bytes long on i386 */ | |
292 | ||
293 | ||
294 | /* IOCTLs: The following are not required (or ignored) when the sg_io_hdr_t | |
295 | interface is used. They are kept for backward compatibility with | |
296 | the original and version 2 drivers. */ | |
297 | ||
298 | #define SG_SET_TIMEOUT 0x2201 /* unit: jiffies (10ms on i386) */ | |
299 | #define SG_GET_TIMEOUT 0x2202 /* yield timeout as _return_ value */ | |
300 | ||
301 | /* Get/set command queuing state per fd (default is SG_DEF_COMMAND_Q. | |
302 | Each time a sg_io_hdr_t object is seen on this file descriptor, this | |
303 | command queuing flag is set on (overriding the previous setting). */ | |
304 | #define SG_GET_COMMAND_Q 0x2270 /* Yields 0 (queuing off) or 1 (on) */ | |
305 | #define SG_SET_COMMAND_Q 0x2271 /* Change queuing state with 0 or 1 */ | |
306 | ||
307 | /* Turn on/off error sense trace (1 and 0 respectively, default is off). | |
308 | Try using: "# cat /proc/scsi/sg/debug" instead in the v3 driver */ | |
309 | #define SG_SET_DEBUG 0x227e /* 0 -> turn off debug */ | |
310 | ||
311 | #define SG_NEXT_CMD_LEN 0x2283 /* override SCSI command length with given | |
312 | number on the next write() on this file descriptor */ | |
313 | ||
314 | ||
315 | /* Defaults, commented if they differ from original sg driver */ | |
316 | #ifdef __KERNEL__ | |
317 | #define SG_DEFAULT_TIMEOUT_USER (60*USER_HZ) /* HZ == 'jiffies in 1 second' */ | |
318 | #else | |
319 | #define SG_DEFAULT_TIMEOUT (60*HZ) /* HZ == 'jiffies in 1 second' */ | |
320 | #endif | |
321 | ||
322 | #define SG_DEF_COMMAND_Q 0 /* command queuing is always on when | |
323 | the new interface is used */ | |
324 | #define SG_DEF_UNDERRUN_FLAG 0 | |
325 | ||
326 | #endif |