Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland...
[linux-2.6] / drivers / ide / ide-acpi.c
1 /*
2  * ide-acpi.c
3  * Provides ACPI support for IDE drives.
4  *
5  * Copyright (C) 2005 Intel Corp.
6  * Copyright (C) 2005 Randy Dunlap
7  * Copyright (C) 2006 SUSE Linux Products GmbH
8  * Copyright (C) 2006 Hannes Reinecke
9  */
10
11 #include <linux/ata.h>
12 #include <linux/delay.h>
13 #include <linux/device.h>
14 #include <linux/errno.h>
15 #include <linux/kernel.h>
16 #include <acpi/acpi.h>
17 #include <linux/ide.h>
18 #include <linux/pci.h>
19
20 #include <acpi/acpi_bus.h>
21 #include <acpi/acnames.h>
22 #include <acpi/acnamesp.h>
23 #include <acpi/acparser.h>
24 #include <acpi/acexcep.h>
25 #include <acpi/acmacros.h>
26 #include <acpi/actypes.h>
27
28 #define REGS_PER_GTF            7
29 struct taskfile_array {
30         u8      tfa[REGS_PER_GTF];      /* regs. 0x1f1 - 0x1f7 */
31 };
32
33 struct GTM_buffer {
34         u32     PIO_speed0;
35         u32     DMA_speed0;
36         u32     PIO_speed1;
37         u32     DMA_speed1;
38         u32     GTM_flags;
39 };
40
41 struct ide_acpi_drive_link {
42         ide_drive_t     *drive;
43         acpi_handle      obj_handle;
44         u8               idbuff[512];
45 };
46
47 struct ide_acpi_hwif_link {
48         ide_hwif_t                      *hwif;
49         acpi_handle                      obj_handle;
50         struct GTM_buffer                gtm;
51         struct ide_acpi_drive_link       master;
52         struct ide_acpi_drive_link       slave;
53 };
54
55 #undef DEBUGGING
56 /* note: adds function name and KERN_DEBUG */
57 #ifdef DEBUGGING
58 #define DEBPRINT(fmt, args...)  \
59                 printk(KERN_DEBUG "%s: " fmt, __FUNCTION__, ## args)
60 #else
61 #define DEBPRINT(fmt, args...)  do {} while (0)
62 #endif  /* DEBUGGING */
63
64 extern int ide_noacpi;
65 extern int ide_noacpitfs;
66 extern int ide_noacpionboot;
67
68 /**
69  * ide_get_dev_handle - finds acpi_handle and PCI device.function
70  * @dev: device to locate
71  * @handle: returned acpi_handle for @dev
72  * @pcidevfn: return PCI device.func for @dev
73  *
74  * Returns the ACPI object handle to the corresponding PCI device.
75  *
76  * Returns 0 on success, <0 on error.
77  */
78 static int ide_get_dev_handle(struct device *dev, acpi_handle *handle,
79                                acpi_integer *pcidevfn)
80 {
81         struct pci_dev *pdev = to_pci_dev(dev);
82         unsigned int bus, devnum, func;
83         acpi_integer addr;
84         acpi_handle dev_handle;
85         struct acpi_buffer buffer = {.length = ACPI_ALLOCATE_BUFFER,
86                                         .pointer = NULL};
87         acpi_status status;
88         struct acpi_device_info *dinfo = NULL;
89         int ret = -ENODEV;
90
91         bus = pdev->bus->number;
92         devnum = PCI_SLOT(pdev->devfn);
93         func = PCI_FUNC(pdev->devfn);
94         /* ACPI _ADR encoding for PCI bus: */
95         addr = (acpi_integer)(devnum << 16 | func);
96
97         DEBPRINT("ENTER: pci %02x:%02x.%01x\n", bus, devnum, func);
98
99         dev_handle = DEVICE_ACPI_HANDLE(dev);
100         if (!dev_handle) {
101                 DEBPRINT("no acpi handle for device\n");
102                 goto err;
103         }
104
105         status = acpi_get_object_info(dev_handle, &buffer);
106         if (ACPI_FAILURE(status)) {
107                 DEBPRINT("get_object_info for device failed\n");
108                 goto err;
109         }
110         dinfo = buffer.pointer;
111         if (dinfo && (dinfo->valid & ACPI_VALID_ADR) &&
112             dinfo->address == addr) {
113                 *pcidevfn = addr;
114                 *handle = dev_handle;
115         } else {
116                 DEBPRINT("get_object_info for device has wrong "
117                         " address: %llu, should be %u\n",
118                         dinfo ? (unsigned long long)dinfo->address : -1ULL,
119                         (unsigned int)addr);
120                 goto err;
121         }
122
123         DEBPRINT("for dev=0x%x.%x, addr=0x%llx, *handle=0x%p\n",
124                  devnum, func, (unsigned long long)addr, *handle);
125         ret = 0;
126 err:
127         kfree(dinfo);
128         return ret;
129 }
130
131 /**
132  * ide_acpi_hwif_get_handle - Get ACPI object handle for a given hwif
133  * @hwif: device to locate
134  *
135  * Retrieves the object handle for a given hwif.
136  *
137  * Returns handle on success, 0 on error.
138  */
139 static acpi_handle ide_acpi_hwif_get_handle(ide_hwif_t *hwif)
140 {
141         struct device           *dev = hwif->gendev.parent;
142         acpi_handle             dev_handle;
143         acpi_integer            pcidevfn;
144         acpi_handle             chan_handle;
145         int                     err;
146
147         DEBPRINT("ENTER: device %s\n", hwif->name);
148
149         if (!dev) {
150                 DEBPRINT("no PCI device for %s\n", hwif->name);
151                 return NULL;
152         }
153
154         err = ide_get_dev_handle(dev, &dev_handle, &pcidevfn);
155         if (err < 0) {
156                 DEBPRINT("ide_get_dev_handle failed (%d)\n", err);
157                 return NULL;
158         }
159
160         /* get child objects of dev_handle == channel objects,
161          * + _their_ children == drive objects */
162         /* channel is hwif->channel */
163         chan_handle = acpi_get_child(dev_handle, hwif->channel);
164         DEBPRINT("chan adr=%d: handle=0x%p\n",
165                  hwif->channel, chan_handle);
166
167         return chan_handle;
168 }
169
170 /**
171  * ide_acpi_drive_get_handle - Get ACPI object handle for a given drive
172  * @drive: device to locate
173  *
174  * Retrieves the object handle of a given drive. According to the ACPI
175  * spec the drive is a child of the hwif.
176  *
177  * Returns handle on success, 0 on error.
178  */
179 static acpi_handle ide_acpi_drive_get_handle(ide_drive_t *drive)
180 {
181         ide_hwif_t      *hwif = HWIF(drive);
182         int              port;
183         acpi_handle      drive_handle;
184
185         if (!hwif->acpidata)
186                 return NULL;
187
188         if (!hwif->acpidata->obj_handle)
189                 return NULL;
190
191         port = hwif->channel ? drive->dn - 2: drive->dn;
192
193         DEBPRINT("ENTER: %s at channel#: %d port#: %d\n",
194                  drive->name, hwif->channel, port);
195
196
197         /* TBD: could also check ACPI object VALID bits */
198         drive_handle = acpi_get_child(hwif->acpidata->obj_handle, port);
199         DEBPRINT("drive %s handle 0x%p\n", drive->name, drive_handle);
200
201         return drive_handle;
202 }
203
204 /**
205  * do_drive_get_GTF - get the drive bootup default taskfile settings
206  * @drive: the drive for which the taskfile settings should be retrieved
207  * @gtf_length: number of bytes of _GTF data returned at @gtf_address
208  * @gtf_address: buffer containing _GTF taskfile arrays
209  *
210  * The _GTF method has no input parameters.
211  * It returns a variable number of register set values (registers
212  * hex 1F1..1F7, taskfiles).
213  * The <variable number> is not known in advance, so have ACPI-CA
214  * allocate the buffer as needed and return it, then free it later.
215  *
216  * The returned @gtf_length and @gtf_address are only valid if the
217  * function return value is 0.
218  */
219 static int do_drive_get_GTF(ide_drive_t *drive,
220                      unsigned int *gtf_length, unsigned long *gtf_address,
221                      unsigned long *obj_loc)
222 {
223         acpi_status                     status;
224         struct acpi_buffer              output;
225         union acpi_object               *out_obj;
226         ide_hwif_t                      *hwif = HWIF(drive);
227         struct device                   *dev = hwif->gendev.parent;
228         int                             err = -ENODEV;
229         int                             port;
230
231         *gtf_length = 0;
232         *gtf_address = 0UL;
233         *obj_loc = 0UL;
234
235         if (ide_noacpi)
236                 return 0;
237
238         if (!dev) {
239                 DEBPRINT("no PCI device for %s\n", hwif->name);
240                 goto out;
241         }
242
243         if (!hwif->acpidata) {
244                 DEBPRINT("no ACPI data for %s\n", hwif->name);
245                 goto out;
246         }
247
248         port = hwif->channel ? drive->dn - 2: drive->dn;
249
250         if (!drive->acpidata) {
251                 if (port == 0) {
252                         drive->acpidata = &hwif->acpidata->master;
253                         hwif->acpidata->master.drive = drive;
254                 } else {
255                         drive->acpidata = &hwif->acpidata->slave;
256                         hwif->acpidata->slave.drive = drive;
257                 }
258         }
259
260         DEBPRINT("ENTER: %s at %s, port#: %d, hard_port#: %d\n",
261                  hwif->name, dev->bus_id, port, hwif->channel);
262
263         if (!drive->present) {
264                 DEBPRINT("%s drive %d:%d not present\n",
265                          hwif->name, hwif->channel, port);
266                 goto out;
267         }
268
269         /* Get this drive's _ADR info. if not already known. */
270         if (!drive->acpidata->obj_handle) {
271                 drive->acpidata->obj_handle = ide_acpi_drive_get_handle(drive);
272                 if (!drive->acpidata->obj_handle) {
273                         DEBPRINT("No ACPI object found for %s\n",
274                                  drive->name);
275                         goto out;
276                 }
277         }
278
279         /* Setting up output buffer */
280         output.length = ACPI_ALLOCATE_BUFFER;
281         output.pointer = NULL;  /* ACPI-CA sets this; save/free it later */
282
283         /* _GTF has no input parameters */
284         err = -EIO;
285         status = acpi_evaluate_object(drive->acpidata->obj_handle, "_GTF",
286                                       NULL, &output);
287         if (ACPI_FAILURE(status)) {
288                 printk(KERN_DEBUG
289                        "%s: Run _GTF error: status = 0x%x\n",
290                        __FUNCTION__, status);
291                 goto out;
292         }
293
294         if (!output.length || !output.pointer) {
295                 DEBPRINT("Run _GTF: "
296                        "length or ptr is NULL (0x%llx, 0x%p)\n",
297                        (unsigned long long)output.length,
298                        output.pointer);
299                 goto out;
300         }
301
302         out_obj = output.pointer;
303         if (out_obj->type != ACPI_TYPE_BUFFER) {
304                 DEBPRINT("Run _GTF: error: "
305                        "expected object type of ACPI_TYPE_BUFFER, "
306                        "got 0x%x\n", out_obj->type);
307                 err = -ENOENT;
308                 kfree(output.pointer);
309                 goto out;
310         }
311
312         if (!out_obj->buffer.length || !out_obj->buffer.pointer ||
313             out_obj->buffer.length % REGS_PER_GTF) {
314                 printk(KERN_ERR
315                        "%s: unexpected GTF length (%d) or addr (0x%p)\n",
316                        __FUNCTION__, out_obj->buffer.length,
317                        out_obj->buffer.pointer);
318                 err = -ENOENT;
319                 kfree(output.pointer);
320                 goto out;
321         }
322
323         *gtf_length = out_obj->buffer.length;
324         *gtf_address = (unsigned long)out_obj->buffer.pointer;
325         *obj_loc = (unsigned long)out_obj;
326         DEBPRINT("returning gtf_length=%d, gtf_address=0x%lx, obj_loc=0x%lx\n",
327                  *gtf_length, *gtf_address, *obj_loc);
328         err = 0;
329 out:
330         return err;
331 }
332
333 /**
334  * taskfile_load_raw - send taskfile registers to drive
335  * @drive: drive to which output is sent
336  * @gtf: raw ATA taskfile register set (0x1f1 - 0x1f7)
337  *
338  * Outputs IDE taskfile to the drive.
339  */
340 static int taskfile_load_raw(ide_drive_t *drive,
341                               const struct taskfile_array *gtf)
342 {
343         ide_task_t args;
344         int err = 0;
345
346         DEBPRINT("(0x1f1-1f7): hex: "
347                "%02x %02x %02x %02x %02x %02x %02x\n",
348                gtf->tfa[0], gtf->tfa[1], gtf->tfa[2],
349                gtf->tfa[3], gtf->tfa[4], gtf->tfa[5], gtf->tfa[6]);
350
351         memset(&args, 0, sizeof(ide_task_t));
352         args.command_type = IDE_DRIVE_TASK_NO_DATA;
353         args.data_phase   = TASKFILE_IN;
354         args.handler      = &task_no_data_intr;
355
356         /* convert gtf to IDE Taskfile */
357         args.tfRegister[1] = gtf->tfa[0];       /* 0x1f1 */
358         args.tfRegister[2] = gtf->tfa[1];       /* 0x1f2 */
359         args.tfRegister[3] = gtf->tfa[2];       /* 0x1f3 */
360         args.tfRegister[4] = gtf->tfa[3];       /* 0x1f4 */
361         args.tfRegister[5] = gtf->tfa[4];       /* 0x1f5 */
362         args.tfRegister[6] = gtf->tfa[5];       /* 0x1f6 */
363         args.tfRegister[7] = gtf->tfa[6];       /* 0x1f7 */
364
365         if (ide_noacpitfs) {
366                 DEBPRINT("_GTF execution disabled\n");
367                 return err;
368         }
369
370         err = ide_raw_taskfile(drive, &args, NULL);
371         if (err)
372                 printk(KERN_ERR "%s: ide_raw_taskfile failed: %u\n",
373                        __FUNCTION__, err);
374
375         return err;
376 }
377
378 /**
379  * do_drive_set_taskfiles - write the drive taskfile settings from _GTF
380  * @drive: the drive to which the taskfile command should be sent
381  * @gtf_length: total number of bytes of _GTF taskfiles
382  * @gtf_address: location of _GTF taskfile arrays
383  *
384  * Write {gtf_address, length gtf_length} in groups of
385  * REGS_PER_GTF bytes.
386  */
387 static int do_drive_set_taskfiles(ide_drive_t *drive,
388                                   unsigned int gtf_length,
389                                   unsigned long gtf_address)
390 {
391         int                     rc = -ENODEV, err;
392         int                     gtf_count = gtf_length / REGS_PER_GTF;
393         int                     ix;
394         struct taskfile_array   *gtf;
395
396         if (ide_noacpi)
397                 return 0;
398
399         DEBPRINT("ENTER: %s, hard_port#: %d\n", drive->name, drive->dn);
400
401         if (!drive->present)
402                 goto out;
403         if (!gtf_count)         /* shouldn't be here */
404                 goto out;
405
406         DEBPRINT("total GTF bytes=%u (0x%x), gtf_count=%d, addr=0x%lx\n",
407                  gtf_length, gtf_length, gtf_count, gtf_address);
408
409         if (gtf_length % REGS_PER_GTF) {
410                 printk(KERN_ERR "%s: unexpected GTF length (%d)\n",
411                        __FUNCTION__, gtf_length);
412                 goto out;
413         }
414
415         rc = 0;
416         for (ix = 0; ix < gtf_count; ix++) {
417                 gtf = (struct taskfile_array *)
418                         (gtf_address + ix * REGS_PER_GTF);
419
420                 /* send all TaskFile registers (0x1f1-0x1f7) *in*that*order* */
421                 err = taskfile_load_raw(drive, gtf);
422                 if (err)
423                         rc = err;
424         }
425
426 out:
427         return rc;
428 }
429
430 /**
431  * ide_acpi_exec_tfs - get then write drive taskfile settings
432  * @drive: the drive for which the taskfile settings should be
433  *         written.
434  *
435  * According to the ACPI spec this should be called after _STM
436  * has been evaluated for the interface. Some ACPI vendors interpret
437  * that as a hard requirement and modify the taskfile according
438  * to the Identify Drive information passed down with _STM.
439  * So one should really make sure to call this only after _STM has
440  * been executed.
441  */
442 int ide_acpi_exec_tfs(ide_drive_t *drive)
443 {
444         int             ret;
445         unsigned int    gtf_length;
446         unsigned long   gtf_address;
447         unsigned long   obj_loc;
448
449         if (ide_noacpi)
450                 return 0;
451
452         DEBPRINT("call get_GTF, drive=%s port=%d\n", drive->name, drive->dn);
453
454         ret = do_drive_get_GTF(drive, &gtf_length, &gtf_address, &obj_loc);
455         if (ret < 0) {
456                 DEBPRINT("get_GTF error (%d)\n", ret);
457                 return ret;
458         }
459
460         DEBPRINT("call set_taskfiles, drive=%s\n", drive->name);
461
462         ret = do_drive_set_taskfiles(drive, gtf_length, gtf_address);
463         kfree((void *)obj_loc);
464         if (ret < 0) {
465                 DEBPRINT("set_taskfiles error (%d)\n", ret);
466         }
467
468         DEBPRINT("ret=%d\n", ret);
469
470         return ret;
471 }
472 EXPORT_SYMBOL_GPL(ide_acpi_exec_tfs);
473
474 /**
475  * ide_acpi_get_timing - get the channel (controller) timings
476  * @hwif: target IDE interface (channel)
477  *
478  * This function executes the _GTM ACPI method for the target channel.
479  *
480  */
481 void ide_acpi_get_timing(ide_hwif_t *hwif)
482 {
483         acpi_status             status;
484         struct acpi_buffer      output;
485         union acpi_object       *out_obj;
486
487         if (ide_noacpi)
488                 return;
489
490         DEBPRINT("ENTER:\n");
491
492         if (!hwif->acpidata) {
493                 DEBPRINT("no ACPI data for %s\n", hwif->name);
494                 return;
495         }
496
497         /* Setting up output buffer for _GTM */
498         output.length = ACPI_ALLOCATE_BUFFER;
499         output.pointer = NULL;  /* ACPI-CA sets this; save/free it later */
500
501         /* _GTM has no input parameters */
502         status = acpi_evaluate_object(hwif->acpidata->obj_handle, "_GTM",
503                                       NULL, &output);
504
505         DEBPRINT("_GTM status: %d, outptr: 0x%p, outlen: 0x%llx\n",
506                  status, output.pointer,
507                  (unsigned long long)output.length);
508
509         if (ACPI_FAILURE(status)) {
510                 DEBPRINT("Run _GTM error: status = 0x%x\n", status);
511                 return;
512         }
513
514         if (!output.length || !output.pointer) {
515                 DEBPRINT("Run _GTM: length or ptr is NULL (0x%llx, 0x%p)\n",
516                        (unsigned long long)output.length,
517                        output.pointer);
518                 kfree(output.pointer);
519                 return;
520         }
521
522         out_obj = output.pointer;
523         if (out_obj->type != ACPI_TYPE_BUFFER) {
524                 kfree(output.pointer);
525                 DEBPRINT("Run _GTM: error: "
526                        "expected object type of ACPI_TYPE_BUFFER, "
527                        "got 0x%x\n", out_obj->type);
528                 return;
529         }
530
531         if (!out_obj->buffer.length || !out_obj->buffer.pointer ||
532             out_obj->buffer.length != sizeof(struct GTM_buffer)) {
533                 kfree(output.pointer);
534                 printk(KERN_ERR
535                         "%s: unexpected _GTM length (0x%x)[should be 0x%zx] or "
536                         "addr (0x%p)\n",
537                         __FUNCTION__, out_obj->buffer.length,
538                         sizeof(struct GTM_buffer), out_obj->buffer.pointer);
539                 return;
540         }
541
542         memcpy(&hwif->acpidata->gtm, out_obj->buffer.pointer,
543                sizeof(struct GTM_buffer));
544
545         DEBPRINT("_GTM info: ptr: 0x%p, len: 0x%x, exp.len: 0x%Zx\n",
546                  out_obj->buffer.pointer, out_obj->buffer.length,
547                  sizeof(struct GTM_buffer));
548
549         DEBPRINT("_GTM fields: 0x%x, 0x%x, 0x%x, 0x%x, 0x%x\n",
550                  hwif->acpidata->gtm.PIO_speed0,
551                  hwif->acpidata->gtm.DMA_speed0,
552                  hwif->acpidata->gtm.PIO_speed1,
553                  hwif->acpidata->gtm.DMA_speed1,
554                  hwif->acpidata->gtm.GTM_flags);
555
556         kfree(output.pointer);
557 }
558 EXPORT_SYMBOL_GPL(ide_acpi_get_timing);
559
560 /**
561  * ide_acpi_push_timing - set the channel (controller) timings
562  * @hwif: target IDE interface (channel)
563  *
564  * This function executes the _STM ACPI method for the target channel.
565  *
566  * _STM requires Identify Drive data, which has to passed as an argument.
567  * Unfortunately hd_driveid is a mangled version which we can't readily
568  * use; hence we'll get the information afresh.
569  */
570 void ide_acpi_push_timing(ide_hwif_t *hwif)
571 {
572         acpi_status             status;
573         struct acpi_object_list input;
574         union acpi_object       in_params[3];
575         struct ide_acpi_drive_link      *master = &hwif->acpidata->master;
576         struct ide_acpi_drive_link      *slave = &hwif->acpidata->slave;
577
578         if (ide_noacpi)
579                 return;
580
581         DEBPRINT("ENTER:\n");
582
583         if (!hwif->acpidata) {
584                 DEBPRINT("no ACPI data for %s\n", hwif->name);
585                 return;
586         }
587
588         /* Give the GTM buffer + drive Identify data to the channel via the
589          * _STM method: */
590         /* setup input parameters buffer for _STM */
591         input.count = 3;
592         input.pointer = in_params;
593         in_params[0].type = ACPI_TYPE_BUFFER;
594         in_params[0].buffer.length = sizeof(struct GTM_buffer);
595         in_params[0].buffer.pointer = (u8 *)&hwif->acpidata->gtm;
596         in_params[1].type = ACPI_TYPE_BUFFER;
597         in_params[1].buffer.length = sizeof(struct hd_driveid);
598         in_params[1].buffer.pointer = (u8 *)&master->idbuff;
599         in_params[2].type = ACPI_TYPE_BUFFER;
600         in_params[2].buffer.length = sizeof(struct hd_driveid);
601         in_params[2].buffer.pointer = (u8 *)&slave->idbuff;
602         /* Output buffer: _STM has no output */
603
604         status = acpi_evaluate_object(hwif->acpidata->obj_handle, "_STM",
605                                       &input, NULL);
606
607         if (ACPI_FAILURE(status)) {
608                 DEBPRINT("Run _STM error: status = 0x%x\n", status);
609         }
610         DEBPRINT("_STM status: %d\n", status);
611 }
612 EXPORT_SYMBOL_GPL(ide_acpi_push_timing);
613
614 /**
615  * ide_acpi_set_state - set the channel power state
616  * @hwif: target IDE interface
617  * @on: state, on/off
618  *
619  * This function executes the _PS0/_PS3 ACPI method to set the power state.
620  * ACPI spec requires _PS0 when IDE power on and _PS3 when power off
621  */
622 void ide_acpi_set_state(ide_hwif_t *hwif, int on)
623 {
624         int unit;
625
626         if (ide_noacpi)
627                 return;
628
629         DEBPRINT("ENTER:\n");
630
631         if (!hwif->acpidata) {
632                 DEBPRINT("no ACPI data for %s\n", hwif->name);
633                 return;
634         }
635         /* channel first and then drives for power on and verse versa for power off */
636         if (on)
637                 acpi_bus_set_power(hwif->acpidata->obj_handle, ACPI_STATE_D0);
638         for (unit = 0; unit < MAX_DRIVES; ++unit) {
639                 ide_drive_t *drive = &hwif->drives[unit];
640
641                 if (!drive->acpidata->obj_handle)
642                         drive->acpidata->obj_handle = ide_acpi_drive_get_handle(drive);
643
644                 if (drive->acpidata->obj_handle && drive->present) {
645                         acpi_bus_set_power(drive->acpidata->obj_handle,
646                                 on? ACPI_STATE_D0: ACPI_STATE_D3);
647                 }
648         }
649         if (!on)
650                 acpi_bus_set_power(hwif->acpidata->obj_handle, ACPI_STATE_D3);
651 }
652 EXPORT_SYMBOL_GPL(ide_acpi_set_state);
653
654 /**
655  * ide_acpi_init - initialize the ACPI link for an IDE interface
656  * @hwif: target IDE interface (channel)
657  *
658  * The ACPI spec is not quite clear when the drive identify buffer
659  * should be obtained. Calling IDENTIFY DEVICE during shutdown
660  * is not the best of ideas as the drive might already being put to
661  * sleep. And obviously we can't call it during resume.
662  * So we get the information during startup; but this means that
663  * any changes during run-time will be lost after resume.
664  */
665 void ide_acpi_init(ide_hwif_t *hwif)
666 {
667         int unit;
668         int                     err;
669         struct ide_acpi_drive_link      *master;
670         struct ide_acpi_drive_link      *slave;
671
672         hwif->acpidata = kzalloc(sizeof(struct ide_acpi_hwif_link), GFP_KERNEL);
673         if (!hwif->acpidata)
674                 return;
675
676         hwif->acpidata->obj_handle = ide_acpi_hwif_get_handle(hwif);
677         if (!hwif->acpidata->obj_handle) {
678                 DEBPRINT("no ACPI object for %s found\n", hwif->name);
679                 kfree(hwif->acpidata);
680                 hwif->acpidata = NULL;
681                 return;
682         }
683
684         /*
685          * The ACPI spec mandates that we send information
686          * for both drives, regardless whether they are connected
687          * or not.
688          */
689         hwif->acpidata->master.drive = &hwif->drives[0];
690         hwif->drives[0].acpidata = &hwif->acpidata->master;
691         master = &hwif->acpidata->master;
692
693         hwif->acpidata->slave.drive = &hwif->drives[1];
694         hwif->drives[1].acpidata = &hwif->acpidata->slave;
695         slave = &hwif->acpidata->slave;
696
697
698         /*
699          * Send IDENTIFY for each drive
700          */
701         if (master->drive->present) {
702                 err = taskfile_lib_get_identify(master->drive, master->idbuff);
703                 if (err) {
704                         DEBPRINT("identify device %s failed (%d)\n",
705                                  master->drive->name, err);
706                 }
707         }
708
709         if (slave->drive->present) {
710                 err = taskfile_lib_get_identify(slave->drive, slave->idbuff);
711                 if (err) {
712                         DEBPRINT("identify device %s failed (%d)\n",
713                                  slave->drive->name, err);
714                 }
715         }
716
717         if (ide_noacpionboot) {
718                 DEBPRINT("ACPI methods disabled on boot\n");
719                 return;
720         }
721
722         /* ACPI _PS0 before _STM */
723         ide_acpi_set_state(hwif, 1);
724         /*
725          * ACPI requires us to call _STM on startup
726          */
727         ide_acpi_get_timing(hwif);
728         ide_acpi_push_timing(hwif);
729
730         for (unit = 0; unit < MAX_DRIVES; ++unit) {
731                 ide_drive_t *drive = &hwif->drives[unit];
732
733                 if (drive->present) {
734                         /* Execute ACPI startup code */
735                         ide_acpi_exec_tfs(drive);
736                 }
737         }
738 }
739 EXPORT_SYMBOL_GPL(ide_acpi_init);