xref: /haiku/src/add-ons/kernel/bus_managers/acpi/acpica/components/hardware/hwregs.c (revision 776c58b2b56d8bcf33638a2ecb6c697f95a1cbf3)
1 /*******************************************************************************
2  *
3  * Module Name: hwregs - Read/write access functions for the various ACPI
4  *                       control and status registers.
5  *
6  ******************************************************************************/
7 
8 /******************************************************************************
9  *
10  * 1. Copyright Notice
11  *
12  * Some or all of this work - Copyright (c) 1999 - 2012, Intel Corp.
13  * All rights reserved.
14  *
15  * 2. License
16  *
17  * 2.1. This is your license from Intel Corp. under its intellectual property
18  * rights. You may have additional license terms from the party that provided
19  * you this software, covering your right to use that party's intellectual
20  * property rights.
21  *
22  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
23  * copy of the source code appearing in this file ("Covered Code") an
24  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
25  * base code distributed originally by Intel ("Original Intel Code") to copy,
26  * make derivatives, distribute, use and display any portion of the Covered
27  * Code in any form, with the right to sublicense such rights; and
28  *
29  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
30  * license (with the right to sublicense), under only those claims of Intel
31  * patents that are infringed by the Original Intel Code, to make, use, sell,
32  * offer to sell, and import the Covered Code and derivative works thereof
33  * solely to the minimum extent necessary to exercise the above copyright
34  * license, and in no event shall the patent license extend to any additions
35  * to or modifications of the Original Intel Code. No other license or right
36  * is granted directly or by implication, estoppel or otherwise;
37  *
38  * The above copyright and patent license is granted only if the following
39  * conditions are met:
40  *
41  * 3. Conditions
42  *
43  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
44  * Redistribution of source code of any substantial portion of the Covered
45  * Code or modification with rights to further distribute source must include
46  * the above Copyright Notice, the above License, this list of Conditions,
47  * and the following Disclaimer and Export Compliance provision. In addition,
48  * Licensee must cause all Covered Code to which Licensee contributes to
49  * contain a file documenting the changes Licensee made to create that Covered
50  * Code and the date of any change. Licensee must include in that file the
51  * documentation of any changes made by any predecessor Licensee. Licensee
52  * must include a prominent statement that the modification is derived,
53  * directly or indirectly, from Original Intel Code.
54  *
55  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
56  * Redistribution of source code of any substantial portion of the Covered
57  * Code or modification without rights to further distribute source must
58  * include the following Disclaimer and Export Compliance provision in the
59  * documentation and/or other materials provided with distribution. In
60  * addition, Licensee may not authorize further sublicense of source of any
61  * portion of the Covered Code, and must include terms to the effect that the
62  * license from Licensee to its licensee is limited to the intellectual
63  * property embodied in the software Licensee provides to its licensee, and
64  * not to intellectual property embodied in modifications its licensee may
65  * make.
66  *
67  * 3.3. Redistribution of Executable. Redistribution in executable form of any
68  * substantial portion of the Covered Code or modification must reproduce the
69  * above Copyright Notice, and the following Disclaimer and Export Compliance
70  * provision in the documentation and/or other materials provided with the
71  * distribution.
72  *
73  * 3.4. Intel retains all right, title, and interest in and to the Original
74  * Intel Code.
75  *
76  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
77  * Intel shall be used in advertising or otherwise to promote the sale, use or
78  * other dealings in products derived from or relating to the Covered Code
79  * without prior written authorization from Intel.
80  *
81  * 4. Disclaimer and Export Compliance
82  *
83  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
84  * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
85  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
86  * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
87  * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
88  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
89  * PARTICULAR PURPOSE.
90  *
91  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
92  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
93  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
94  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
95  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
96  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
97  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
98  * LIMITED REMEDY.
99  *
100  * 4.3. Licensee shall not export, either directly or indirectly, any of this
101  * software or system incorporating such software without first obtaining any
102  * required license or other approval from the U. S. Department of Commerce or
103  * any other agency or department of the United States Government. In the
104  * event Licensee exports any such software from the United States or
105  * re-exports any such software from a foreign destination, Licensee shall
106  * ensure that the distribution and export/re-export of the software is in
107  * compliance with all laws, regulations, orders, or other restrictions of the
108  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
109  * any of its subsidiaries will export/re-export any technical data, process,
110  * software, or service, directly or indirectly, to any country for which the
111  * United States government or any agency thereof requires an export license,
112  * other governmental approval, or letter of assurance, without first obtaining
113  * such license, approval or letter.
114  *
115  *****************************************************************************/
116 
117 #define __HWREGS_C__
118 
119 #include "acpi.h"
120 #include "accommon.h"
121 #include "acevents.h"
122 
123 #define _COMPONENT          ACPI_HARDWARE
124         ACPI_MODULE_NAME    ("hwregs")
125 
126 
127 #if (!ACPI_REDUCED_HARDWARE)
128 
129 /* Local Prototypes */
130 
131 static ACPI_STATUS
132 AcpiHwReadMultiple (
133     UINT32                  *Value,
134     ACPI_GENERIC_ADDRESS    *RegisterA,
135     ACPI_GENERIC_ADDRESS    *RegisterB);
136 
137 static ACPI_STATUS
138 AcpiHwWriteMultiple (
139     UINT32                  Value,
140     ACPI_GENERIC_ADDRESS    *RegisterA,
141     ACPI_GENERIC_ADDRESS    *RegisterB);
142 
143 #endif /* !ACPI_REDUCED_HARDWARE */
144 
145 /******************************************************************************
146  *
147  * FUNCTION:    AcpiHwValidateRegister
148  *
149  * PARAMETERS:  Reg                 - GAS register structure
150  *              MaxBitWidth         - Max BitWidth supported (32 or 64)
151  *              Address             - Pointer to where the gas->address
152  *                                    is returned
153  *
154  * RETURN:      Status
155  *
156  * DESCRIPTION: Validate the contents of a GAS register. Checks the GAS
157  *              pointer, Address, SpaceId, BitWidth, and BitOffset.
158  *
159  ******************************************************************************/
160 
161 ACPI_STATUS
162 AcpiHwValidateRegister (
163     ACPI_GENERIC_ADDRESS    *Reg,
164     UINT8                   MaxBitWidth,
165     UINT64                  *Address)
166 {
167 
168     /* Must have a valid pointer to a GAS structure */
169 
170     if (!Reg)
171     {
172         return (AE_BAD_PARAMETER);
173     }
174 
175     /*
176      * Copy the target address. This handles possible alignment issues.
177      * Address must not be null. A null address also indicates an optional
178      * ACPI register that is not supported, so no error message.
179      */
180     ACPI_MOVE_64_TO_64 (Address, &Reg->Address);
181     if (!(*Address))
182     {
183         return (AE_BAD_ADDRESS);
184     }
185 
186     /* Validate the SpaceID */
187 
188     if ((Reg->SpaceId != ACPI_ADR_SPACE_SYSTEM_MEMORY) &&
189         (Reg->SpaceId != ACPI_ADR_SPACE_SYSTEM_IO))
190     {
191         ACPI_ERROR ((AE_INFO,
192             "Unsupported address space: 0x%X", Reg->SpaceId));
193         return (AE_SUPPORT);
194     }
195 
196     /* Validate the BitWidth */
197 
198     if ((Reg->BitWidth != 8) &&
199         (Reg->BitWidth != 16) &&
200         (Reg->BitWidth != 32) &&
201         (Reg->BitWidth != MaxBitWidth))
202     {
203         ACPI_ERROR ((AE_INFO,
204             "Unsupported register bit width: 0x%X", Reg->BitWidth));
205         return (AE_SUPPORT);
206     }
207 
208     /* Validate the BitOffset. Just a warning for now. */
209 
210     if (Reg->BitOffset != 0)
211     {
212         ACPI_WARNING ((AE_INFO,
213             "Unsupported register bit offset: 0x%X", Reg->BitOffset));
214     }
215 
216     return (AE_OK);
217 }
218 
219 
220 /******************************************************************************
221  *
222  * FUNCTION:    AcpiHwRead
223  *
224  * PARAMETERS:  Value               - Where the value is returned
225  *              Reg                 - GAS register structure
226  *
227  * RETURN:      Status
228  *
229  * DESCRIPTION: Read from either memory or IO space. This is a 32-bit max
230  *              version of AcpiRead, used internally since the overhead of
231  *              64-bit values is not needed.
232  *
233  * LIMITATIONS: <These limitations also apply to AcpiHwWrite>
234  *      BitWidth must be exactly 8, 16, or 32.
235  *      SpaceID must be SystemMemory or SystemIO.
236  *      BitOffset and AccessWidth are currently ignored, as there has
237  *          not been a need to implement these.
238  *
239  ******************************************************************************/
240 
241 ACPI_STATUS
242 AcpiHwRead (
243     UINT32                  *Value,
244     ACPI_GENERIC_ADDRESS    *Reg)
245 {
246     UINT64                  Address;
247     UINT64                  Value64;
248     ACPI_STATUS             Status;
249 
250 
251     ACPI_FUNCTION_NAME (HwRead);
252 
253 
254     /* Validate contents of the GAS register */
255 
256     Status = AcpiHwValidateRegister (Reg, 32, &Address);
257     if (ACPI_FAILURE (Status))
258     {
259         return (Status);
260     }
261 
262     /* Initialize entire 32-bit return value to zero */
263 
264     *Value = 0;
265 
266     /*
267      * Two address spaces supported: Memory or IO. PCI_Config is
268      * not supported here because the GAS structure is insufficient
269      */
270     if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_MEMORY)
271     {
272         Status = AcpiOsReadMemory ((ACPI_PHYSICAL_ADDRESS)
273                     Address, &Value64, Reg->BitWidth);
274 
275         *Value = (UINT32) Value64;
276     }
277     else /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
278     {
279         Status = AcpiHwReadPort ((ACPI_IO_ADDRESS)
280                     Address, Value, Reg->BitWidth);
281     }
282 
283     ACPI_DEBUG_PRINT ((ACPI_DB_IO,
284         "Read:  %8.8X width %2d from %8.8X%8.8X (%s)\n",
285         *Value, Reg->BitWidth, ACPI_FORMAT_UINT64 (Address),
286         AcpiUtGetRegionName (Reg->SpaceId)));
287 
288     return (Status);
289 }
290 
291 
292 /******************************************************************************
293  *
294  * FUNCTION:    AcpiHwWrite
295  *
296  * PARAMETERS:  Value               - Value to be written
297  *              Reg                 - GAS register structure
298  *
299  * RETURN:      Status
300  *
301  * DESCRIPTION: Write to either memory or IO space. This is a 32-bit max
302  *              version of AcpiWrite, used internally since the overhead of
303  *              64-bit values is not needed.
304  *
305  ******************************************************************************/
306 
307 ACPI_STATUS
308 AcpiHwWrite (
309     UINT32                  Value,
310     ACPI_GENERIC_ADDRESS    *Reg)
311 {
312     UINT64                  Address;
313     ACPI_STATUS             Status;
314 
315 
316     ACPI_FUNCTION_NAME (HwWrite);
317 
318 
319     /* Validate contents of the GAS register */
320 
321     Status = AcpiHwValidateRegister (Reg, 32, &Address);
322     if (ACPI_FAILURE (Status))
323     {
324         return (Status);
325     }
326 
327     /*
328      * Two address spaces supported: Memory or IO. PCI_Config is
329      * not supported here because the GAS structure is insufficient
330      */
331     if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_MEMORY)
332     {
333         Status = AcpiOsWriteMemory ((ACPI_PHYSICAL_ADDRESS)
334                     Address, (UINT64) Value, Reg->BitWidth);
335     }
336     else /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
337     {
338         Status = AcpiHwWritePort ((ACPI_IO_ADDRESS)
339                     Address, Value, Reg->BitWidth);
340     }
341 
342     ACPI_DEBUG_PRINT ((ACPI_DB_IO,
343         "Wrote: %8.8X width %2d   to %8.8X%8.8X (%s)\n",
344         Value, Reg->BitWidth, ACPI_FORMAT_UINT64 (Address),
345         AcpiUtGetRegionName (Reg->SpaceId)));
346 
347     return (Status);
348 }
349 
350 
351 #if (!ACPI_REDUCED_HARDWARE)
352 /*******************************************************************************
353  *
354  * FUNCTION:    AcpiHwClearAcpiStatus
355  *
356  * PARAMETERS:  None
357  *
358  * RETURN:      Status
359  *
360  * DESCRIPTION: Clears all fixed and general purpose status bits
361  *
362  ******************************************************************************/
363 
364 ACPI_STATUS
365 AcpiHwClearAcpiStatus (
366     void)
367 {
368     ACPI_STATUS             Status;
369     ACPI_CPU_FLAGS          LockFlags = 0;
370 
371 
372     ACPI_FUNCTION_TRACE (HwClearAcpiStatus);
373 
374 
375     ACPI_DEBUG_PRINT ((ACPI_DB_IO, "About to write %04X to %8.8X%8.8X\n",
376         ACPI_BITMASK_ALL_FIXED_STATUS,
377         ACPI_FORMAT_UINT64 (AcpiGbl_XPm1aStatus.Address)));
378 
379     LockFlags = AcpiOsAcquireLock (AcpiGbl_HardwareLock);
380 
381     /* Clear the fixed events in PM1 A/B */
382 
383     Status = AcpiHwRegisterWrite (ACPI_REGISTER_PM1_STATUS,
384                 ACPI_BITMASK_ALL_FIXED_STATUS);
385     if (ACPI_FAILURE (Status))
386     {
387         goto UnlockAndExit;
388     }
389 
390     /* Clear the GPE Bits in all GPE registers in all GPE blocks */
391 
392     Status = AcpiEvWalkGpeList (AcpiHwClearGpeBlock, NULL);
393 
394 UnlockAndExit:
395     AcpiOsReleaseLock (AcpiGbl_HardwareLock, LockFlags);
396     return_ACPI_STATUS (Status);
397 }
398 
399 
400 /*******************************************************************************
401  *
402  * FUNCTION:    AcpiHwGetBitRegisterInfo
403  *
404  * PARAMETERS:  RegisterId          - Index of ACPI Register to access
405  *
406  * RETURN:      The bitmask to be used when accessing the register
407  *
408  * DESCRIPTION: Map RegisterId into a register bitmask.
409  *
410  ******************************************************************************/
411 
412 ACPI_BIT_REGISTER_INFO *
413 AcpiHwGetBitRegisterInfo (
414     UINT32                  RegisterId)
415 {
416     ACPI_FUNCTION_ENTRY ();
417 
418 
419     if (RegisterId > ACPI_BITREG_MAX)
420     {
421         ACPI_ERROR ((AE_INFO, "Invalid BitRegister ID: 0x%X", RegisterId));
422         return (NULL);
423     }
424 
425     return (&AcpiGbl_BitRegisterInfo[RegisterId]);
426 }
427 
428 
429 /******************************************************************************
430  *
431  * FUNCTION:    AcpiHwWritePm1Control
432  *
433  * PARAMETERS:  Pm1aControl         - Value to be written to PM1A control
434  *              Pm1bControl         - Value to be written to PM1B control
435  *
436  * RETURN:      Status
437  *
438  * DESCRIPTION: Write the PM1 A/B control registers. These registers are
439  *              different than than the PM1 A/B status and enable registers
440  *              in that different values can be written to the A/B registers.
441  *              Most notably, the SLP_TYP bits can be different, as per the
442  *              values returned from the _Sx predefined methods.
443  *
444  ******************************************************************************/
445 
446 ACPI_STATUS
447 AcpiHwWritePm1Control (
448     UINT32                  Pm1aControl,
449     UINT32                  Pm1bControl)
450 {
451     ACPI_STATUS             Status;
452 
453 
454     ACPI_FUNCTION_TRACE (HwWritePm1Control);
455 
456 
457     Status = AcpiHwWrite (Pm1aControl, &AcpiGbl_FADT.XPm1aControlBlock);
458     if (ACPI_FAILURE (Status))
459     {
460         return_ACPI_STATUS (Status);
461     }
462 
463     if (AcpiGbl_FADT.XPm1bControlBlock.Address)
464     {
465         Status = AcpiHwWrite (Pm1bControl, &AcpiGbl_FADT.XPm1bControlBlock);
466     }
467     return_ACPI_STATUS (Status);
468 }
469 
470 
471 /******************************************************************************
472  *
473  * FUNCTION:    AcpiHwRegisterRead
474  *
475  * PARAMETERS:  RegisterId          - ACPI Register ID
476  *              ReturnValue         - Where the register value is returned
477  *
478  * RETURN:      Status and the value read.
479  *
480  * DESCRIPTION: Read from the specified ACPI register
481  *
482  ******************************************************************************/
483 
484 ACPI_STATUS
485 AcpiHwRegisterRead (
486     UINT32                  RegisterId,
487     UINT32                  *ReturnValue)
488 {
489     UINT32                  Value = 0;
490     ACPI_STATUS             Status;
491 
492 
493     ACPI_FUNCTION_TRACE (HwRegisterRead);
494 
495 
496     switch (RegisterId)
497     {
498     case ACPI_REGISTER_PM1_STATUS:           /* PM1 A/B: 16-bit access each */
499 
500         Status = AcpiHwReadMultiple (&Value,
501                     &AcpiGbl_XPm1aStatus,
502                     &AcpiGbl_XPm1bStatus);
503         break;
504 
505 
506     case ACPI_REGISTER_PM1_ENABLE:           /* PM1 A/B: 16-bit access each */
507 
508         Status = AcpiHwReadMultiple (&Value,
509                     &AcpiGbl_XPm1aEnable,
510                     &AcpiGbl_XPm1bEnable);
511         break;
512 
513 
514     case ACPI_REGISTER_PM1_CONTROL:          /* PM1 A/B: 16-bit access each */
515 
516         Status = AcpiHwReadMultiple (&Value,
517                     &AcpiGbl_FADT.XPm1aControlBlock,
518                     &AcpiGbl_FADT.XPm1bControlBlock);
519 
520         /*
521          * Zero the write-only bits. From the ACPI specification, "Hardware
522          * Write-Only Bits": "Upon reads to registers with write-only bits,
523          * software masks out all write-only bits."
524          */
525         Value &= ~ACPI_PM1_CONTROL_WRITEONLY_BITS;
526         break;
527 
528 
529     case ACPI_REGISTER_PM2_CONTROL:          /* 8-bit access */
530 
531         Status = AcpiHwRead (&Value, &AcpiGbl_FADT.XPm2ControlBlock);
532         break;
533 
534 
535     case ACPI_REGISTER_PM_TIMER:             /* 32-bit access */
536 
537         Status = AcpiHwRead (&Value, &AcpiGbl_FADT.XPmTimerBlock);
538         break;
539 
540 
541     case ACPI_REGISTER_SMI_COMMAND_BLOCK:    /* 8-bit access */
542 
543         Status = AcpiHwReadPort (AcpiGbl_FADT.SmiCommand, &Value, 8);
544         break;
545 
546 
547     default:
548         ACPI_ERROR ((AE_INFO, "Unknown Register ID: 0x%X",
549             RegisterId));
550         Status = AE_BAD_PARAMETER;
551         break;
552     }
553 
554     if (ACPI_SUCCESS (Status))
555     {
556         *ReturnValue = Value;
557     }
558 
559     return_ACPI_STATUS (Status);
560 }
561 
562 
563 /******************************************************************************
564  *
565  * FUNCTION:    AcpiHwRegisterWrite
566  *
567  * PARAMETERS:  RegisterId          - ACPI Register ID
568  *              Value               - The value to write
569  *
570  * RETURN:      Status
571  *
572  * DESCRIPTION: Write to the specified ACPI register
573  *
574  * NOTE: In accordance with the ACPI specification, this function automatically
575  * preserves the value of the following bits, meaning that these bits cannot be
576  * changed via this interface:
577  *
578  * PM1_CONTROL[0] = SCI_EN
579  * PM1_CONTROL[9]
580  * PM1_STATUS[11]
581  *
582  * ACPI References:
583  * 1) Hardware Ignored Bits: When software writes to a register with ignored
584  *      bit fields, it preserves the ignored bit fields
585  * 2) SCI_EN: OSPM always preserves this bit position
586  *
587  ******************************************************************************/
588 
589 ACPI_STATUS
590 AcpiHwRegisterWrite (
591     UINT32                  RegisterId,
592     UINT32                  Value)
593 {
594     ACPI_STATUS             Status;
595     UINT32                  ReadValue;
596 
597 
598     ACPI_FUNCTION_TRACE (HwRegisterWrite);
599 
600 
601     switch (RegisterId)
602     {
603     case ACPI_REGISTER_PM1_STATUS:           /* PM1 A/B: 16-bit access each */
604         /*
605          * Handle the "ignored" bit in PM1 Status. According to the ACPI
606          * specification, ignored bits are to be preserved when writing.
607          * Normally, this would mean a read/modify/write sequence. However,
608          * preserving a bit in the status register is different. Writing a
609          * one clears the status, and writing a zero preserves the status.
610          * Therefore, we must always write zero to the ignored bit.
611          *
612          * This behavior is clarified in the ACPI 4.0 specification.
613          */
614         Value &= ~ACPI_PM1_STATUS_PRESERVED_BITS;
615 
616         Status = AcpiHwWriteMultiple (Value,
617                     &AcpiGbl_XPm1aStatus,
618                     &AcpiGbl_XPm1bStatus);
619         break;
620 
621 
622     case ACPI_REGISTER_PM1_ENABLE:           /* PM1 A/B: 16-bit access each */
623 
624         Status = AcpiHwWriteMultiple (Value,
625                     &AcpiGbl_XPm1aEnable,
626                     &AcpiGbl_XPm1bEnable);
627         break;
628 
629 
630     case ACPI_REGISTER_PM1_CONTROL:          /* PM1 A/B: 16-bit access each */
631 
632         /*
633          * Perform a read first to preserve certain bits (per ACPI spec)
634          * Note: This includes SCI_EN, we never want to change this bit
635          */
636         Status = AcpiHwReadMultiple (&ReadValue,
637                     &AcpiGbl_FADT.XPm1aControlBlock,
638                     &AcpiGbl_FADT.XPm1bControlBlock);
639         if (ACPI_FAILURE (Status))
640         {
641             goto Exit;
642         }
643 
644         /* Insert the bits to be preserved */
645 
646         ACPI_INSERT_BITS (Value, ACPI_PM1_CONTROL_PRESERVED_BITS, ReadValue);
647 
648         /* Now we can write the data */
649 
650         Status = AcpiHwWriteMultiple (Value,
651                     &AcpiGbl_FADT.XPm1aControlBlock,
652                     &AcpiGbl_FADT.XPm1bControlBlock);
653         break;
654 
655 
656     case ACPI_REGISTER_PM2_CONTROL:          /* 8-bit access */
657 
658         /*
659          * For control registers, all reserved bits must be preserved,
660          * as per the ACPI spec.
661          */
662         Status = AcpiHwRead (&ReadValue, &AcpiGbl_FADT.XPm2ControlBlock);
663         if (ACPI_FAILURE (Status))
664         {
665             goto Exit;
666         }
667 
668         /* Insert the bits to be preserved */
669 
670         ACPI_INSERT_BITS (Value, ACPI_PM2_CONTROL_PRESERVED_BITS, ReadValue);
671 
672         Status = AcpiHwWrite (Value, &AcpiGbl_FADT.XPm2ControlBlock);
673         break;
674 
675 
676     case ACPI_REGISTER_PM_TIMER:             /* 32-bit access */
677 
678         Status = AcpiHwWrite (Value, &AcpiGbl_FADT.XPmTimerBlock);
679         break;
680 
681 
682     case ACPI_REGISTER_SMI_COMMAND_BLOCK:    /* 8-bit access */
683 
684         /* SMI_CMD is currently always in IO space */
685 
686         Status = AcpiHwWritePort (AcpiGbl_FADT.SmiCommand, Value, 8);
687         break;
688 
689 
690     default:
691         ACPI_ERROR ((AE_INFO, "Unknown Register ID: 0x%X",
692             RegisterId));
693         Status = AE_BAD_PARAMETER;
694         break;
695     }
696 
697 Exit:
698     return_ACPI_STATUS (Status);
699 }
700 
701 
702 /******************************************************************************
703  *
704  * FUNCTION:    AcpiHwReadMultiple
705  *
706  * PARAMETERS:  Value               - Where the register value is returned
707  *              RegisterA           - First ACPI register (required)
708  *              RegisterB           - Second ACPI register (optional)
709  *
710  * RETURN:      Status
711  *
712  * DESCRIPTION: Read from the specified two-part ACPI register (such as PM1 A/B)
713  *
714  ******************************************************************************/
715 
716 static ACPI_STATUS
717 AcpiHwReadMultiple (
718     UINT32                  *Value,
719     ACPI_GENERIC_ADDRESS    *RegisterA,
720     ACPI_GENERIC_ADDRESS    *RegisterB)
721 {
722     UINT32                  ValueA = 0;
723     UINT32                  ValueB = 0;
724     ACPI_STATUS             Status;
725 
726 
727     /* The first register is always required */
728 
729     Status = AcpiHwRead (&ValueA, RegisterA);
730     if (ACPI_FAILURE (Status))
731     {
732         return (Status);
733     }
734 
735     /* Second register is optional */
736 
737     if (RegisterB->Address)
738     {
739         Status = AcpiHwRead (&ValueB, RegisterB);
740         if (ACPI_FAILURE (Status))
741         {
742             return (Status);
743         }
744     }
745 
746     /*
747      * OR the two return values together. No shifting or masking is necessary,
748      * because of how the PM1 registers are defined in the ACPI specification:
749      *
750      * "Although the bits can be split between the two register blocks (each
751      * register block has a unique pointer within the FADT), the bit positions
752      * are maintained. The register block with unimplemented bits (that is,
753      * those implemented in the other register block) always returns zeros,
754      * and writes have no side effects"
755      */
756     *Value = (ValueA | ValueB);
757     return (AE_OK);
758 }
759 
760 
761 /******************************************************************************
762  *
763  * FUNCTION:    AcpiHwWriteMultiple
764  *
765  * PARAMETERS:  Value               - The value to write
766  *              RegisterA           - First ACPI register (required)
767  *              RegisterB           - Second ACPI register (optional)
768  *
769  * RETURN:      Status
770  *
771  * DESCRIPTION: Write to the specified two-part ACPI register (such as PM1 A/B)
772  *
773  ******************************************************************************/
774 
775 static ACPI_STATUS
776 AcpiHwWriteMultiple (
777     UINT32                  Value,
778     ACPI_GENERIC_ADDRESS    *RegisterA,
779     ACPI_GENERIC_ADDRESS    *RegisterB)
780 {
781     ACPI_STATUS             Status;
782 
783 
784     /* The first register is always required */
785 
786     Status = AcpiHwWrite (Value, RegisterA);
787     if (ACPI_FAILURE (Status))
788     {
789         return (Status);
790     }
791 
792     /*
793      * Second register is optional
794      *
795      * No bit shifting or clearing is necessary, because of how the PM1
796      * registers are defined in the ACPI specification:
797      *
798      * "Although the bits can be split between the two register blocks (each
799      * register block has a unique pointer within the FADT), the bit positions
800      * are maintained. The register block with unimplemented bits (that is,
801      * those implemented in the other register block) always returns zeros,
802      * and writes have no side effects"
803      */
804     if (RegisterB->Address)
805     {
806         Status = AcpiHwWrite (Value, RegisterB);
807     }
808 
809     return (Status);
810 }
811 
812 #endif /* !ACPI_REDUCED_HARDWARE */
813