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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 - 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 |
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