xref: /titanic_44/usr/src/uts/intel/io/acpica/hardware/hwregs.c (revision 11d0a659fdd288190c17d8600ecd218e9a9b546d)
1 
2 /*******************************************************************************
3  *
4  * Module Name: hwregs - Read/write access functions for the various ACPI
5  *                       control and status registers.
6  *
7  ******************************************************************************/
8 
9 /******************************************************************************
10  *
11  * 1. Copyright Notice
12  *
13  * Some or all of this work - Copyright (c) 1999 - 2009, Intel Corp.
14  * All rights reserved.
15  *
16  * 2. License
17  *
18  * 2.1. This is your license from Intel Corp. under its intellectual property
19  * rights.  You may have additional license terms from the party that provided
20  * you this software, covering your right to use that party's intellectual
21  * property rights.
22  *
23  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
24  * copy of the source code appearing in this file ("Covered Code") an
25  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
26  * base code distributed originally by Intel ("Original Intel Code") to copy,
27  * make derivatives, distribute, use and display any portion of the Covered
28  * Code in any form, with the right to sublicense such rights; and
29  *
30  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
31  * license (with the right to sublicense), under only those claims of Intel
32  * patents that are infringed by the Original Intel Code, to make, use, sell,
33  * offer to sell, and import the Covered Code and derivative works thereof
34  * solely to the minimum extent necessary to exercise the above copyright
35  * license, and in no event shall the patent license extend to any additions
36  * to or modifications of the Original Intel Code.  No other license or right
37  * is granted directly or by implication, estoppel or otherwise;
38  *
39  * The above copyright and patent license is granted only if the following
40  * conditions are met:
41  *
42  * 3. Conditions
43  *
44  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
45  * Redistribution of source code of any substantial portion of the Covered
46  * Code or modification with rights to further distribute source must include
47  * the above Copyright Notice, the above License, this list of Conditions,
48  * and the following Disclaimer and Export Compliance provision.  In addition,
49  * Licensee must cause all Covered Code to which Licensee contributes to
50  * contain a file documenting the changes Licensee made to create that Covered
51  * Code and the date of any change.  Licensee must include in that file the
52  * documentation of any changes made by any predecessor Licensee.  Licensee
53  * must include a prominent statement that the modification is derived,
54  * directly or indirectly, from Original Intel Code.
55  *
56  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
57  * Redistribution of source code of any substantial portion of the Covered
58  * Code or modification without rights to further distribute source must
59  * include the following Disclaimer and Export Compliance provision in the
60  * documentation and/or other materials provided with distribution.  In
61  * addition, Licensee may not authorize further sublicense of source of any
62  * portion of the Covered Code, and must include terms to the effect that the
63  * license from Licensee to its licensee is limited to the intellectual
64  * property embodied in the software Licensee provides to its licensee, and
65  * not to intellectual property embodied in modifications its licensee may
66  * make.
67  *
68  * 3.3. Redistribution of Executable. Redistribution in executable form of any
69  * substantial portion of the Covered Code or modification must reproduce the
70  * above Copyright Notice, and the following Disclaimer and Export Compliance
71  * provision in the documentation and/or other materials provided with the
72  * distribution.
73  *
74  * 3.4. Intel retains all right, title, and interest in and to the Original
75  * Intel Code.
76  *
77  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
78  * Intel shall be used in advertising or otherwise to promote the sale, use or
79  * other dealings in products derived from or relating to the Covered Code
80  * without prior written authorization from Intel.
81  *
82  * 4. Disclaimer and Export Compliance
83  *
84  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
85  * HERE.  ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
86  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT,  ASSISTANCE,
87  * INSTALLATION, TRAINING OR OTHER SERVICES.  INTEL WILL NOT PROVIDE ANY
88  * UPDATES, ENHANCEMENTS OR EXTENSIONS.  INTEL SPECIFICALLY DISCLAIMS ANY
89  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
90  * PARTICULAR PURPOSE.
91  *
92  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
93  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
94  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
95  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
96  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
97  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.  THESE LIMITATIONS
98  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
99  * LIMITED REMEDY.
100  *
101  * 4.3. Licensee shall not export, either directly or indirectly, any of this
102  * software or system incorporating such software without first obtaining any
103  * required license or other approval from the U. S. Department of Commerce or
104  * any other agency or department of the United States Government.  In the
105  * event Licensee exports any such software from the United States or
106  * re-exports any such software from a foreign destination, Licensee shall
107  * ensure that the distribution and export/re-export of the software is in
108  * compliance with all laws, regulations, orders, or other restrictions of the
109  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
110  * any of its subsidiaries will export/re-export any technical data, process,
111  * software, or service, directly or indirectly, to any country for which the
112  * United States government or any agency thereof requires an export license,
113  * other governmental approval, or letter of assurance, without first obtaining
114  * such license, approval or letter.
115  *
116  *****************************************************************************/
117 
118 #define __HWREGS_C__
119 
120 #include "acpi.h"
121 #include "accommon.h"
122 #include "acevents.h"
123 
124 #define _COMPONENT          ACPI_HARDWARE
125         ACPI_MODULE_NAME    ("hwregs")
126 
127 
128 /* Local Prototypes */
129 
130 static ACPI_STATUS
131 AcpiHwReadMultiple (
132     UINT32                  *Value,
133     ACPI_GENERIC_ADDRESS    *RegisterA,
134     ACPI_GENERIC_ADDRESS    *RegisterB);
135 
136 static ACPI_STATUS
137 AcpiHwWriteMultiple (
138     UINT32                  Value,
139     ACPI_GENERIC_ADDRESS    *RegisterA,
140     ACPI_GENERIC_ADDRESS    *RegisterB);
141 
142 
143 /******************************************************************************
144  *
145  * FUNCTION:    AcpiHwValidateRegister
146  *
147  * PARAMETERS:  Reg                 - GAS register structure
148  *              MaxBitWidth         - Max BitWidth supported (32 or 64)
149  *              Address             - Pointer to where the gas->address
150  *                                    is returned
151  *
152  * RETURN:      Status
153  *
154  * DESCRIPTION: Validate the contents of a GAS register. Checks the GAS
155  *              pointer, Address, SpaceId, BitWidth, and BitOffset.
156  *
157  ******************************************************************************/
158 
159 ACPI_STATUS
160 AcpiHwValidateRegister (
161     ACPI_GENERIC_ADDRESS    *Reg,
162     UINT8                   MaxBitWidth,
163     UINT64                  *Address)
164 {
165 
166     /* Must have a valid pointer to a GAS structure */
167 
168     if (!Reg)
169     {
170         return (AE_BAD_PARAMETER);
171     }
172 
173     /*
174      * Copy the target address. This handles possible alignment issues.
175      * Address must not be null. A null address also indicates an optional
176      * ACPI register that is not supported, so no error message.
177      */
178     ACPI_MOVE_64_TO_64 (Address, &Reg->Address);
179     if (!(*Address))
180     {
181         return (AE_BAD_ADDRESS);
182     }
183 
184     /* Validate the SpaceID */
185 
186     if ((Reg->SpaceId != ACPI_ADR_SPACE_SYSTEM_MEMORY) &&
187         (Reg->SpaceId != ACPI_ADR_SPACE_SYSTEM_IO))
188     {
189         ACPI_ERROR ((AE_INFO,
190             "Unsupported address space: 0x%X", Reg->SpaceId));
191         return (AE_SUPPORT);
192     }
193 
194     /* Validate the BitWidth */
195 
196     if ((Reg->BitWidth != 8) &&
197         (Reg->BitWidth != 16) &&
198         (Reg->BitWidth != 32) &&
199         (Reg->BitWidth != MaxBitWidth))
200     {
201         ACPI_ERROR ((AE_INFO,
202             "Unsupported register bit width: 0x%X", Reg->BitWidth));
203         return (AE_SUPPORT);
204     }
205 
206     /* Validate the BitOffset. Just a warning for now. */
207 
208     if (Reg->BitOffset != 0)
209     {
210         ACPI_WARNING ((AE_INFO,
211             "Unsupported register bit offset: 0x%X", Reg->BitOffset));
212     }
213 
214     return (AE_OK);
215 }
216 
217 
218 /******************************************************************************
219  *
220  * FUNCTION:    AcpiHwRead
221  *
222  * PARAMETERS:  Value               - Where the value is returned
223  *              Reg                 - GAS register structure
224  *
225  * RETURN:      Status
226  *
227  * DESCRIPTION: Read from either memory or IO space. This is a 32-bit max
228  *              version of AcpiRead, used internally since the overhead of
229  *              64-bit values is not needed.
230  *
231  * LIMITATIONS: <These limitations also apply to AcpiHwWrite>
232  *      BitWidth must be exactly 8, 16, or 32.
233  *      SpaceID must be SystemMemory or SystemIO.
234  *      BitOffset and AccessWidth are currently ignored, as there has
235  *          not been a need to implement these.
236  *
237  ******************************************************************************/
238 
239 ACPI_STATUS
240 AcpiHwRead (
241     UINT32                  *Value,
242     ACPI_GENERIC_ADDRESS    *Reg)
243 {
244     UINT64                  Address;
245     ACPI_STATUS             Status;
246 
247 
248     ACPI_FUNCTION_NAME (HwRead);
249 
250 
251     /* Validate contents of the GAS register */
252 
253     Status = AcpiHwValidateRegister (Reg, 32, &Address);
254     if (ACPI_FAILURE (Status))
255     {
256         return (Status);
257     }
258 
259     /* Initialize entire 32-bit return value to zero */
260 
261     *Value = 0;
262 
263     /*
264      * Two address spaces supported: Memory or IO. PCI_Config is
265      * not supported here because the GAS structure is insufficient
266      */
267     if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_MEMORY)
268     {
269         Status = AcpiOsReadMemory ((ACPI_PHYSICAL_ADDRESS)
270                     Address, Value, Reg->BitWidth);
271     }
272     else /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
273     {
274         Status = AcpiHwReadPort ((ACPI_IO_ADDRESS)
275                     Address, Value, Reg->BitWidth);
276     }
277 
278     ACPI_DEBUG_PRINT ((ACPI_DB_IO,
279         "Read:  %8.8X width %2d from %8.8X%8.8X (%s)\n",
280         *Value, Reg->BitWidth, ACPI_FORMAT_UINT64 (Address),
281         AcpiUtGetRegionName (Reg->SpaceId)));
282 
283     return (Status);
284 }
285 
286 
287 /******************************************************************************
288  *
289  * FUNCTION:    AcpiHwWrite
290  *
291  * PARAMETERS:  Value               - Value to be written
292  *              Reg                 - GAS register structure
293  *
294  * RETURN:      Status
295  *
296  * DESCRIPTION: Write to either memory or IO space. This is a 32-bit max
297  *              version of AcpiWrite, used internally since the overhead of
298  *              64-bit values is not needed.
299  *
300  ******************************************************************************/
301 
302 ACPI_STATUS
303 AcpiHwWrite (
304     UINT32                  Value,
305     ACPI_GENERIC_ADDRESS    *Reg)
306 {
307     UINT64                  Address;
308     ACPI_STATUS             Status;
309 
310 
311     ACPI_FUNCTION_NAME (HwWrite);
312 
313 
314     /* Validate contents of the GAS register */
315 
316     Status = AcpiHwValidateRegister (Reg, 32, &Address);
317     if (ACPI_FAILURE (Status))
318     {
319         return (Status);
320     }
321 
322     /*
323      * Two address spaces supported: Memory or IO. PCI_Config is
324      * not supported here because the GAS structure is insufficient
325      */
326     if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_MEMORY)
327     {
328         Status = AcpiOsWriteMemory ((ACPI_PHYSICAL_ADDRESS)
329                     Address, Value, Reg->BitWidth);
330     }
331     else /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
332     {
333         Status = AcpiHwWritePort ((ACPI_IO_ADDRESS)
334                     Address, Value, Reg->BitWidth);
335     }
336 
337     ACPI_DEBUG_PRINT ((ACPI_DB_IO,
338         "Wrote: %8.8X width %2d   to %8.8X%8.8X (%s)\n",
339         Value, Reg->BitWidth, ACPI_FORMAT_UINT64 (Address),
340         AcpiUtGetRegionName (Reg->SpaceId)));
341 
342     return (Status);
343 }
344 
345 
346 /*******************************************************************************
347  *
348  * FUNCTION:    AcpiHwClearAcpiStatus
349  *
350  * PARAMETERS:  None
351  *
352  * RETURN:      Status
353  *
354  * DESCRIPTION: Clears all fixed and general purpose status bits
355  *
356  ******************************************************************************/
357 
358 ACPI_STATUS
359 AcpiHwClearAcpiStatus (
360     void)
361 {
362     ACPI_STATUS             Status;
363     ACPI_CPU_FLAGS          LockFlags = 0;
364 
365 
366     ACPI_FUNCTION_TRACE (HwClearAcpiStatus);
367 
368 
369     ACPI_DEBUG_PRINT ((ACPI_DB_IO, "About to write %04X to %8.8X%8.8X\n",
370         ACPI_BITMASK_ALL_FIXED_STATUS,
371         ACPI_FORMAT_UINT64 (AcpiGbl_XPm1aStatus.Address)));
372 
373     LockFlags = AcpiOsAcquireLock (AcpiGbl_HardwareLock);
374 
375     /* Clear the fixed events in PM1 A/B */
376 
377     Status = AcpiHwRegisterWrite (ACPI_REGISTER_PM1_STATUS,
378                 ACPI_BITMASK_ALL_FIXED_STATUS);
379     if (ACPI_FAILURE (Status))
380     {
381         goto UnlockAndExit;
382     }
383 
384     /* Clear the GPE Bits in all GPE registers in all GPE blocks */
385 
386     Status = AcpiEvWalkGpeList (AcpiHwClearGpeBlock, NULL);
387 
388 UnlockAndExit:
389     AcpiOsReleaseLock (AcpiGbl_HardwareLock, LockFlags);
390     return_ACPI_STATUS (Status);
391 }
392 
393 
394 /*******************************************************************************
395  *
396  * FUNCTION:    AcpiHwGetRegisterBitMask
397  *
398  * PARAMETERS:  RegisterId          - Index of ACPI Register to access
399  *
400  * RETURN:      The bitmask to be used when accessing the register
401  *
402  * DESCRIPTION: Map RegisterId into a register bitmask.
403  *
404  ******************************************************************************/
405 
406 ACPI_BIT_REGISTER_INFO *
407 AcpiHwGetBitRegisterInfo (
408     UINT32                  RegisterId)
409 {
410     ACPI_FUNCTION_ENTRY ();
411 
412 
413     if (RegisterId > ACPI_BITREG_MAX)
414     {
415         ACPI_ERROR ((AE_INFO, "Invalid BitRegister ID: %X", RegisterId));
416         return (NULL);
417     }
418 
419     return (&AcpiGbl_BitRegisterInfo[RegisterId]);
420 }
421 
422 
423 /******************************************************************************
424  *
425  * FUNCTION:    AcpiHwWritePm1Control
426  *
427  * PARAMETERS:  Pm1aControl         - Value to be written to PM1A control
428  *              Pm1bControl         - Value to be written to PM1B control
429  *
430  * RETURN:      Status
431  *
432  * DESCRIPTION: Write the PM1 A/B control registers. These registers are
433  *              different than than the PM1 A/B status and enable registers
434  *              in that different values can be written to the A/B registers.
435  *              Most notably, the SLP_TYP bits can be different, as per the
436  *              values returned from the _Sx predefined methods.
437  *
438  ******************************************************************************/
439 
440 ACPI_STATUS
441 AcpiHwWritePm1Control (
442     UINT32                  Pm1aControl,
443     UINT32                  Pm1bControl)
444 {
445     ACPI_STATUS             Status;
446 
447 
448     ACPI_FUNCTION_TRACE (HwWritePm1Control);
449 
450 
451     Status = AcpiHwWrite (Pm1aControl, &AcpiGbl_FADT.XPm1aControlBlock);
452     if (ACPI_FAILURE (Status))
453     {
454         return_ACPI_STATUS (Status);
455     }
456 
457     if (AcpiGbl_FADT.XPm1bControlBlock.Address)
458     {
459         Status = AcpiHwWrite (Pm1bControl, &AcpiGbl_FADT.XPm1bControlBlock);
460     }
461     return_ACPI_STATUS (Status);
462 }
463 
464 
465 /******************************************************************************
466  *
467  * FUNCTION:    AcpiHwRegisterRead
468  *
469  * PARAMETERS:  RegisterId          - ACPI Register ID
470  *              ReturnValue         - Where the register value is returned
471  *
472  * RETURN:      Status and the value read.
473  *
474  * DESCRIPTION: Read from the specified ACPI register
475  *
476  ******************************************************************************/
477 
478 ACPI_STATUS
479 AcpiHwRegisterRead (
480     UINT32                  RegisterId,
481     UINT32                  *ReturnValue)
482 {
483     UINT32                  Value = 0;
484     ACPI_STATUS             Status;
485 
486 
487     ACPI_FUNCTION_TRACE (HwRegisterRead);
488 
489 
490     switch (RegisterId)
491     {
492     case ACPI_REGISTER_PM1_STATUS:           /* PM1 A/B: 16-bit access each */
493 
494         Status = AcpiHwReadMultiple (&Value,
495                     &AcpiGbl_XPm1aStatus,
496                     &AcpiGbl_XPm1bStatus);
497         break;
498 
499 
500     case ACPI_REGISTER_PM1_ENABLE:           /* PM1 A/B: 16-bit access each */
501 
502         Status = AcpiHwReadMultiple (&Value,
503                     &AcpiGbl_XPm1aEnable,
504                     &AcpiGbl_XPm1bEnable);
505         break;
506 
507 
508     case ACPI_REGISTER_PM1_CONTROL:          /* PM1 A/B: 16-bit access each */
509 
510         Status = AcpiHwReadMultiple (&Value,
511                     &AcpiGbl_FADT.XPm1aControlBlock,
512                     &AcpiGbl_FADT.XPm1bControlBlock);
513 
514         /*
515          * Zero the write-only bits. From the ACPI specification, "Hardware
516          * Write-Only Bits": "Upon reads to registers with write-only bits,
517          * software masks out all write-only bits."
518          */
519         Value &= ~ACPI_PM1_CONTROL_WRITEONLY_BITS;
520         break;
521 
522 
523     case ACPI_REGISTER_PM2_CONTROL:          /* 8-bit access */
524 
525         Status = AcpiHwRead (&Value, &AcpiGbl_FADT.XPm2ControlBlock);
526         break;
527 
528 
529     case ACPI_REGISTER_PM_TIMER:             /* 32-bit access */
530 
531         Status = AcpiHwRead (&Value, &AcpiGbl_FADT.XPmTimerBlock);
532         break;
533 
534 
535     case ACPI_REGISTER_SMI_COMMAND_BLOCK:    /* 8-bit access */
536 
537         Status = AcpiHwReadPort (AcpiGbl_FADT.SmiCommand, &Value, 8);
538         break;
539 
540 
541     default:
542         ACPI_ERROR ((AE_INFO, "Unknown Register ID: %X",
543             RegisterId));
544         Status = AE_BAD_PARAMETER;
545         break;
546     }
547 
548     if (ACPI_SUCCESS (Status))
549     {
550         *ReturnValue = Value;
551     }
552 
553     return_ACPI_STATUS (Status);
554 }
555 
556 
557 /******************************************************************************
558  *
559  * FUNCTION:    AcpiHwRegisterWrite
560  *
561  * PARAMETERS:  RegisterId          - ACPI Register ID
562  *              Value               - The value to write
563  *
564  * RETURN:      Status
565  *
566  * DESCRIPTION: Write to the specified ACPI register
567  *
568  * NOTE: In accordance with the ACPI specification, this function automatically
569  * preserves the value of the following bits, meaning that these bits cannot be
570  * changed via this interface:
571  *
572  * PM1_CONTROL[0] = SCI_EN
573  * PM1_CONTROL[9]
574  * PM1_STATUS[11]
575  *
576  * ACPI References:
577  * 1) Hardware Ignored Bits: When software writes to a register with ignored
578  *      bit fields, it preserves the ignored bit fields
579  * 2) SCI_EN: OSPM always preserves this bit position
580  *
581  ******************************************************************************/
582 
583 ACPI_STATUS
584 AcpiHwRegisterWrite (
585     UINT32                  RegisterId,
586     UINT32                  Value)
587 {
588     ACPI_STATUS             Status;
589     UINT32                  ReadValue;
590 
591 
592     ACPI_FUNCTION_TRACE (HwRegisterWrite);
593 
594 
595     switch (RegisterId)
596     {
597     case ACPI_REGISTER_PM1_STATUS:           /* PM1 A/B: 16-bit access each */
598         /*
599          * Handle the "ignored" bit in PM1 Status. According to the ACPI
600          * specification, ignored bits are to be preserved when writing.
601          * Normally, this would mean a read/modify/write sequence. However,
602          * preserving a bit in the status register is different. Writing a
603          * one clears the status, and writing a zero preserves the status.
604          * Therefore, we must always write zero to the ignored bit.
605          *
606          * This behavior is clarified in the ACPI 4.0 specification.
607          */
608         Value &= ~ACPI_PM1_STATUS_PRESERVED_BITS;
609 
610         Status = AcpiHwWriteMultiple (Value,
611                     &AcpiGbl_XPm1aStatus,
612                     &AcpiGbl_XPm1bStatus);
613         break;
614 
615 
616     case ACPI_REGISTER_PM1_ENABLE:           /* PM1 A/B: 16-bit access each */
617 
618         Status = AcpiHwWriteMultiple (Value,
619                     &AcpiGbl_XPm1aEnable,
620                     &AcpiGbl_XPm1bEnable);
621         break;
622 
623 
624     case ACPI_REGISTER_PM1_CONTROL:          /* PM1 A/B: 16-bit access each */
625 
626         /*
627          * Perform a read first to preserve certain bits (per ACPI spec)
628          * Note: This includes SCI_EN, we never want to change this bit
629          */
630         Status = AcpiHwReadMultiple (&ReadValue,
631                     &AcpiGbl_FADT.XPm1aControlBlock,
632                     &AcpiGbl_FADT.XPm1bControlBlock);
633         if (ACPI_FAILURE (Status))
634         {
635             goto Exit;
636         }
637 
638         /* Insert the bits to be preserved */
639 
640         ACPI_INSERT_BITS (Value, ACPI_PM1_CONTROL_PRESERVED_BITS, ReadValue);
641 
642         /* Now we can write the data */
643 
644         Status = AcpiHwWriteMultiple (Value,
645                     &AcpiGbl_FADT.XPm1aControlBlock,
646                     &AcpiGbl_FADT.XPm1bControlBlock);
647         break;
648 
649 
650     case ACPI_REGISTER_PM2_CONTROL:          /* 8-bit access */
651 
652         /*
653          * For control registers, all reserved bits must be preserved,
654          * as per the ACPI spec.
655          */
656         Status = AcpiHwRead (&ReadValue, &AcpiGbl_FADT.XPm2ControlBlock);
657         if (ACPI_FAILURE (Status))
658         {
659             goto Exit;
660         }
661 
662         /* Insert the bits to be preserved */
663 
664         ACPI_INSERT_BITS (Value, ACPI_PM2_CONTROL_PRESERVED_BITS, ReadValue);
665 
666         Status = AcpiHwWrite (Value, &AcpiGbl_FADT.XPm2ControlBlock);
667         break;
668 
669 
670     case ACPI_REGISTER_PM_TIMER:             /* 32-bit access */
671 
672         Status = AcpiHwWrite (Value, &AcpiGbl_FADT.XPmTimerBlock);
673         break;
674 
675 
676     case ACPI_REGISTER_SMI_COMMAND_BLOCK:    /* 8-bit access */
677 
678         /* SMI_CMD is currently always in IO space */
679 
680         Status = AcpiHwWritePort (AcpiGbl_FADT.SmiCommand, Value, 8);
681         break;
682 
683 
684     default:
685         ACPI_ERROR ((AE_INFO, "Unknown Register ID: %X",
686             RegisterId));
687         Status = AE_BAD_PARAMETER;
688         break;
689     }
690 
691 Exit:
692     return_ACPI_STATUS (Status);
693 }
694 
695 
696 /******************************************************************************
697  *
698  * FUNCTION:    AcpiHwReadMultiple
699  *
700  * PARAMETERS:  Value               - Where the register value is returned
701  *              RegisterA           - First ACPI register (required)
702  *              RegisterB           - Second ACPI register (optional)
703  *
704  * RETURN:      Status
705  *
706  * DESCRIPTION: Read from the specified two-part ACPI register (such as PM1 A/B)
707  *
708  ******************************************************************************/
709 
710 static ACPI_STATUS
711 AcpiHwReadMultiple (
712     UINT32                  *Value,
713     ACPI_GENERIC_ADDRESS    *RegisterA,
714     ACPI_GENERIC_ADDRESS    *RegisterB)
715 {
716     UINT32                  ValueA = 0;
717     UINT32                  ValueB = 0;
718     ACPI_STATUS             Status;
719 
720 
721     /* The first register is always required */
722 
723     Status = AcpiHwRead (&ValueA, RegisterA);
724     if (ACPI_FAILURE (Status))
725     {
726         return (Status);
727     }
728 
729     /* Second register is optional */
730 
731     if (RegisterB->Address)
732     {
733         Status = AcpiHwRead (&ValueB, RegisterB);
734         if (ACPI_FAILURE (Status))
735         {
736             return (Status);
737         }
738     }
739 
740     /*
741      * OR the two return values together. No shifting or masking is necessary,
742      * because of how the PM1 registers are defined in the ACPI specification:
743      *
744      * "Although the bits can be split between the two register blocks (each
745      * register block has a unique pointer within the FADT), the bit positions
746      * are maintained. The register block with unimplemented bits (that is,
747      * those implemented in the other register block) always returns zeros,
748      * and writes have no side effects"
749      */
750     *Value = (ValueA | ValueB);
751     return (AE_OK);
752 }
753 
754 
755 /******************************************************************************
756  *
757  * FUNCTION:    AcpiHwWriteMultiple
758  *
759  * PARAMETERS:  Value               - The value to write
760  *              RegisterA           - First ACPI register (required)
761  *              RegisterB           - Second ACPI register (optional)
762  *
763  * RETURN:      Status
764  *
765  * DESCRIPTION: Write to the specified two-part ACPI register (such as PM1 A/B)
766  *
767  ******************************************************************************/
768 
769 static ACPI_STATUS
770 AcpiHwWriteMultiple (
771     UINT32                  Value,
772     ACPI_GENERIC_ADDRESS    *RegisterA,
773     ACPI_GENERIC_ADDRESS    *RegisterB)
774 {
775     ACPI_STATUS             Status;
776 
777 
778     /* The first register is always required */
779 
780     Status = AcpiHwWrite (Value, RegisterA);
781     if (ACPI_FAILURE (Status))
782     {
783         return (Status);
784     }
785 
786     /*
787      * Second register is optional
788      *
789      * No bit shifting or clearing is necessary, because of how the PM1
790      * registers are defined in the ACPI specification:
791      *
792      * "Although the bits can be split between the two register blocks (each
793      * register block has a unique pointer within the FADT), the bit positions
794      * are maintained. The register block with unimplemented bits (that is,
795      * those implemented in the other register block) always returns zeros,
796      * and writes have no side effects"
797      */
798     if (RegisterB->Address)
799     {
800         Status = AcpiHwWrite (Value, RegisterB);
801     }
802 
803     return (Status);
804 }
805 
806