1 ==============================
2 Summary of `HDIO_` ioctl calls
3 ==============================
4
5 - Edward A. Falk <efalk@google.com>
6
7 November, 2004
8
9 This document attempts to describe the ioctl(2) calls supported by
10 the HD/IDE layer. These are by-and-large implemented (as of Linux 5.11)
11 drivers/ata/libata-scsi.c.
12
13 ioctl values are listed in <linux/hdreg.h>. As of this writing, they
14 are as follows:
15
16 ioctls that pass argument pointers to user space:
17
18 ======================= =======================================
19 HDIO_GETGEO get device geometry
20 HDIO_GET_32BIT get current io_32bit setting
21 HDIO_GET_IDENTITY get IDE identification info
22 HDIO_DRIVE_TASKFILE execute raw taskfile
23 HDIO_DRIVE_TASK execute task and special drive command
24 HDIO_DRIVE_CMD execute a special drive command
25 ======================= =======================================
26
27 ioctls that pass non-pointer values:
28
29 ======================= =======================================
30 HDIO_SET_32BIT change io_32bit flags
31 ======================= =======================================
32
33
34 The information that follows was determined from reading kernel source
35 code. It is likely that some corrections will be made over time.
36
37 ------------------------------------------------------------------------------
38
39 General:
40
41 Unless otherwise specified, all ioctl calls return 0 on success
42 and -1 with errno set to an appropriate value on error.
43
44 Unless otherwise specified, all ioctl calls return -1 and set
45 errno to EFAULT on a failed attempt to copy data to or from user
46 address space.
47
48 Unless otherwise specified, all data structures and constants
49 are defined in <linux/hdreg.h>
50
51 ------------------------------------------------------------------------------
52
53 HDIO_GETGEO
54 get device geometry
55
56
57 usage::
58
59 struct hd_geometry geom;
60
61 ioctl(fd, HDIO_GETGEO, &geom);
62
63
64 inputs:
65 none
66
67
68
69 outputs:
70 hd_geometry structure containing:
71
72
73 ========= ==================================
74 heads number of heads
75 sectors number of sectors/track
76 cylinders number of cylinders, mod 65536
77 start starting sector of this partition.
78 ========= ==================================
79
80
81 error returns:
82 - EINVAL
83
84 if the device is not a disk drive or floppy drive,
85 or if the user passes a null pointer
86
87
88 notes:
89 Not particularly useful with modern disk drives, whose geometry
90 is a polite fiction anyway. Modern drives are addressed
91 purely by sector number nowadays (lba addressing), and the
92 drive geometry is an abstraction which is actually subject
93 to change. Currently (as of Nov 2004), the geometry values
94 are the "bios" values -- presumably the values the drive had
95 when Linux first booted.
96
97 In addition, the cylinders field of the hd_geometry is an
98 unsigned short, meaning that on most architectures, this
99 ioctl will not return a meaningful value on drives with more
100 than 65535 tracks.
101
102 The start field is unsigned long, meaning that it will not
103 contain a meaningful value for disks over 219 Gb in size.
104
105
106
107 HDIO_GET_IDENTITY
108 get IDE identification info
109
110
111 usage::
112
113 unsigned char identity[512];
114
115 ioctl(fd, HDIO_GET_IDENTITY, identity);
116
117 inputs:
118 none
119
120
121
122 outputs:
123 ATA drive identity information. For full description, see
124 the IDENTIFY DEVICE and IDENTIFY PACKET DEVICE commands in
125 the ATA specification.
126
127 error returns:
128 - EINVAL Called on a partition instead of the whole disk device
129 - ENOMSG IDENTIFY DEVICE information not available
130
131 notes:
132 Returns information that was obtained when the drive was
133 probed. Some of this information is subject to change, and
134 this ioctl does not re-probe the drive to update the
135 information.
136
137 This information is also available from /proc/ide/hdX/identify
138
139
140
141 HDIO_GET_32BIT
142 get current io_32bit setting
143
144
145 usage::
146
147 long val;
148
149 ioctl(fd, HDIO_GET_32BIT, &val);
150
151 inputs:
152 none
153
154
155
156 outputs:
157 The value of the current io_32bit setting
158
159
160
161 notes:
162 0=16-bit, 1=32-bit, 2,3 = 32bit+sync
163
164
165
166 HDIO_DRIVE_TASKFILE
167 execute raw taskfile
168
169
170 Note:
171 If you don't have a copy of the ANSI ATA specification
172 handy, you should probably ignore this ioctl.
173
174 - Execute an ATA disk command directly by writing the "taskfile"
175 registers of the drive. Requires ADMIN and RAWIO access
176 privileges.
177
178 usage::
179
180 struct {
181
182 ide_task_request_t req_task;
183 u8 outbuf[OUTPUT_SIZE];
184 u8 inbuf[INPUT_SIZE];
185 } task;
186 memset(&task.req_task, 0, sizeof(task.req_task));
187 task.req_task.out_size = sizeof(task.outbuf);
188 task.req_task.in_size = sizeof(task.inbuf);
189 ...
190 ioctl(fd, HDIO_DRIVE_TASKFILE, &task);
191 ...
192
193 inputs:
194
195 (See below for details on memory area passed to ioctl.)
196
197 ============ ===================================================
198 io_ports[8] values to be written to taskfile registers
199 hob_ports[8] high-order bytes, for extended commands.
200 out_flags flags indicating which registers are valid
201 in_flags flags indicating which registers should be returned
202 data_phase see below
203 req_cmd command type to be executed
204 out_size size of output buffer
205 outbuf buffer of data to be transmitted to disk
206 inbuf buffer of data to be received from disk (see [1])
207 ============ ===================================================
208
209 outputs:
210
211 =========== ====================================================
212 io_ports[] values returned in the taskfile registers
213 hob_ports[] high-order bytes, for extended commands.
214 out_flags flags indicating which registers are valid (see [2])
215 in_flags flags indicating which registers should be returned
216 outbuf buffer of data to be transmitted to disk (see [1])
217 inbuf buffer of data to be received from disk
218 =========== ====================================================
219
220 error returns:
221 - EACCES CAP_SYS_ADMIN or CAP_SYS_RAWIO privilege not set.
222 - ENOMSG Device is not a disk drive.
223 - ENOMEM Unable to allocate memory for task
224 - EFAULT req_cmd == TASKFILE_IN_OUT (not implemented as of 2.6.8)
225 - EPERM
226
227 req_cmd == TASKFILE_MULTI_OUT and drive
228 multi-count not yet set.
229 - EIO Drive failed the command.
230
231 notes:
232
233 [1] READ THE FOLLOWING NOTES *CAREFULLY*. THIS IOCTL IS
234 FULL OF GOTCHAS. Extreme caution should be used with using
235 this ioctl. A mistake can easily corrupt data or hang the
236 system.
237
238 [2] Both the input and output buffers are copied from the
239 user and written back to the user, even when not used.
240
241 [3] If one or more bits are set in out_flags and in_flags is
242 zero, the following values are used for in_flags.all and
243 written back into in_flags on completion.
244
245 * IDE_TASKFILE_STD_IN_FLAGS | (IDE_HOB_STD_IN_FLAGS << 8)
246 if LBA48 addressing is enabled for the drive
247 * IDE_TASKFILE_STD_IN_FLAGS
248 if CHS/LBA28
249
250 The association between in_flags.all and each enable
251 bitfield flips depending on endianness; fortunately, TASKFILE
252 only uses inflags.b.data bit and ignores all other bits.
253 The end result is that, on any endian machines, it has no
254 effect other than modifying in_flags on completion.
255
256 [4] The default value of SELECT is (0xa0|DEV_bit|LBA_bit)
257 except for four drives per port chipsets. For four drives
258 per port chipsets, it's (0xa0|DEV_bit|LBA_bit) for the first
259 pair and (0x80|DEV_bit|LBA_bit) for the second pair.
260
261 [5] The argument to the ioctl is a pointer to a region of
262 memory containing a ide_task_request_t structure, followed
263 by an optional buffer of data to be transmitted to the
264 drive, followed by an optional buffer to receive data from
265 the drive.
266
267 Command is passed to the disk drive via the ide_task_request_t
268 structure, which contains these fields:
269
270 ============ ===============================================
271 io_ports[8] values for the taskfile registers
272 hob_ports[8] high-order bytes, for extended commands
273 out_flags flags indicating which entries in the
274 io_ports[] and hob_ports[] arrays
275 contain valid values. Type ide_reg_valid_t.
276 in_flags flags indicating which entries in the
277 io_ports[] and hob_ports[] arrays
278 are expected to contain valid values
279 on return.
280 data_phase See below
281 req_cmd Command type, see below
282 out_size output (user->drive) buffer size, bytes
283 in_size input (drive->user) buffer size, bytes
284 ============ ===============================================
285
286 When out_flags is zero, the following registers are loaded.
287
288 ============ ===============================================
289 HOB_FEATURE If the drive supports LBA48
290 HOB_NSECTOR If the drive supports LBA48
291 HOB_SECTOR If the drive supports LBA48
292 HOB_LCYL If the drive supports LBA48
293 HOB_HCYL If the drive supports LBA48
294 FEATURE
295 NSECTOR
296 SECTOR
297 LCYL
298 HCYL
299 SELECT First, masked with 0xE0 if LBA48, 0xEF
300 otherwise; then, or'ed with the default
301 value of SELECT.
302 ============ ===============================================
303
304 If any bit in out_flags is set, the following registers are loaded.
305
306 ============ ===============================================
307 HOB_DATA If out_flags.b.data is set. HOB_DATA will
308 travel on DD8-DD15 on little endian machines
309 and on DD0-DD7 on big endian machines.
310 DATA If out_flags.b.data is set. DATA will
311 travel on DD0-DD7 on little endian machines
312 and on DD8-DD15 on big endian machines.
313 HOB_NSECTOR If out_flags.b.nsector_hob is set
314 HOB_SECTOR If out_flags.b.sector_hob is set
315 HOB_LCYL If out_flags.b.lcyl_hob is set
316 HOB_HCYL If out_flags.b.hcyl_hob is set
317 FEATURE If out_flags.b.feature is set
318 NSECTOR If out_flags.b.nsector is set
319 SECTOR If out_flags.b.sector is set
320 LCYL If out_flags.b.lcyl is set
321 HCYL If out_flags.b.hcyl is set
322 SELECT Or'ed with the default value of SELECT and
323 loaded regardless of out_flags.b.select.
324 ============ ===============================================
325
326 Taskfile registers are read back from the drive into
327 {io|hob}_ports[] after the command completes iff one of the
328 following conditions is met; otherwise, the original values
329 will be written back, unchanged.
330
331 1. The drive fails the command (EIO).
332 2. One or more than one bits are set in out_flags.
333 3. The requested data_phase is TASKFILE_NO_DATA.
334
335 ============ ===============================================
336 HOB_DATA If in_flags.b.data is set. It will contain
337 DD8-DD15 on little endian machines and
338 DD0-DD7 on big endian machines.
339 DATA If in_flags.b.data is set. It will contain
340 DD0-DD7 on little endian machines and
341 DD8-DD15 on big endian machines.
342 HOB_FEATURE If the drive supports LBA48
343 HOB_NSECTOR If the drive supports LBA48
344 HOB_SECTOR If the drive supports LBA48
345 HOB_LCYL If the drive supports LBA48
346 HOB_HCYL If the drive supports LBA48
347 NSECTOR
348 SECTOR
349 LCYL
350 HCYL
351 ============ ===============================================
352
353 The data_phase field describes the data transfer to be
354 performed. Value is one of:
355
356 =================== ========================================
357 TASKFILE_IN
358 TASKFILE_MULTI_IN
359 TASKFILE_OUT
360 TASKFILE_MULTI_OUT
361 TASKFILE_IN_OUT
362 TASKFILE_IN_DMA
363 TASKFILE_IN_DMAQ == IN_DMA (queueing not supported)
364 TASKFILE_OUT_DMA
365 TASKFILE_OUT_DMAQ == OUT_DMA (queueing not supported)
366 TASKFILE_P_IN unimplemented
367 TASKFILE_P_IN_DMA unimplemented
368 TASKFILE_P_IN_DMAQ unimplemented
369 TASKFILE_P_OUT unimplemented
370 TASKFILE_P_OUT_DMA unimplemented
371 TASKFILE_P_OUT_DMAQ unimplemented
372 =================== ========================================
373
374 The req_cmd field classifies the command type. It may be
375 one of:
376
377 ======================== =======================================
378 IDE_DRIVE_TASK_NO_DATA
379 IDE_DRIVE_TASK_SET_XFER unimplemented
380 IDE_DRIVE_TASK_IN
381 IDE_DRIVE_TASK_OUT unimplemented
382 IDE_DRIVE_TASK_RAW_WRITE
383 ======================== =======================================
384
385 [6] Do not access {in|out}_flags->all except for resetting
386 all the bits. Always access individual bit fields. ->all
387 value will flip depending on endianness. For the same
388 reason, do not use IDE_{TASKFILE|HOB}_STD_{OUT|IN}_FLAGS
389 constants defined in hdreg.h.
390
391
392
393 HDIO_DRIVE_CMD
394 execute a special drive command
395
396
397 Note: If you don't have a copy of the ANSI ATA specification
398 handy, you should probably ignore this ioctl.
399
400 usage::
401
402 u8 args[4+XFER_SIZE];
403
404 ...
405 ioctl(fd, HDIO_DRIVE_CMD, args);
406
407 inputs:
408 Commands other than WIN_SMART:
409
410 ======= =======
411 args[0] COMMAND
412 args[1] NSECTOR
413 args[2] FEATURE
414 args[3] NSECTOR
415 ======= =======
416
417 WIN_SMART:
418
419 ======= =======
420 args[0] COMMAND
421 args[1] SECTOR
422 args[2] FEATURE
423 args[3] NSECTOR
424 ======= =======
425
426 outputs:
427 args[] buffer is filled with register values followed by any
428
429
430 data returned by the disk.
431
432 ======== ====================================================
433 args[0] status
434 args[1] error
435 args[2] NSECTOR
436 args[3] undefined
437 args[4+] NSECTOR * 512 bytes of data returned by the command.
438 ======== ====================================================
439
440 error returns:
441 - EACCES Access denied: requires CAP_SYS_RAWIO
442 - ENOMEM Unable to allocate memory for task
443 - EIO Drive reports error
444
445 notes:
446
447 [1] For commands other than WIN_SMART, args[1] should equal
448 args[3]. SECTOR, LCYL and HCYL are undefined. For
449 WIN_SMART, 0x4f and 0xc2 are loaded into LCYL and HCYL
450 respectively. In both cases SELECT will contain the default
451 value for the drive. Please refer to HDIO_DRIVE_TASKFILE
452 notes for the default value of SELECT.
453
454 [2] If NSECTOR value is greater than zero and the drive sets
455 DRQ when interrupting for the command, NSECTOR * 512 bytes
456 are read from the device into the area following NSECTOR.
457 In the above example, the area would be
458 args[4..4+XFER_SIZE]. 16bit PIO is used regardless of
459 HDIO_SET_32BIT setting.
460
461 [3] If COMMAND == WIN_SETFEATURES && FEATURE == SETFEATURES_XFER
462 && NSECTOR >= XFER_SW_DMA_0 && the drive supports any DMA
463 mode, IDE driver will try to tune the transfer mode of the
464 drive accordingly.
465
466
467
468 HDIO_DRIVE_TASK
469 execute task and special drive command
470
471
472 Note: If you don't have a copy of the ANSI ATA specification
473 handy, you should probably ignore this ioctl.
474
475 usage::
476
477 u8 args[7];
478
479 ...
480 ioctl(fd, HDIO_DRIVE_TASK, args);
481
482 inputs:
483 Taskfile register values:
484
485 ======= =======
486 args[0] COMMAND
487 args[1] FEATURE
488 args[2] NSECTOR
489 args[3] SECTOR
490 args[4] LCYL
491 args[5] HCYL
492 args[6] SELECT
493 ======= =======
494
495 outputs:
496 Taskfile register values:
497
498
499 ======= =======
500 args[0] status
501 args[1] error
502 args[2] NSECTOR
503 args[3] SECTOR
504 args[4] LCYL
505 args[5] HCYL
506 args[6] SELECT
507 ======= =======
508
509 error returns:
510 - EACCES Access denied: requires CAP_SYS_RAWIO
511 - ENOMEM Unable to allocate memory for task
512 - ENOMSG Device is not a disk drive.
513 - EIO Drive failed the command.
514
515 notes:
516
517 [1] DEV bit (0x10) of SELECT register is ignored and the
518 appropriate value for the drive is used. All other bits
519 are used unaltered.
520
521
522
523 HDIO_SET_32BIT
524 change io_32bit flags
525
526
527 usage::
528
529 int val;
530
531 ioctl(fd, HDIO_SET_32BIT, val);
532
533 inputs:
534 New value for io_32bit flag
535
536
537
538 outputs:
539 none
540
541
542
543 error return:
544 - EINVAL Called on a partition instead of the whole disk device
545 - EACCES Access denied: requires CAP_SYS_ADMIN
546 - EINVAL value out of range [0 3]
547 - EBUSY Controller busy
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