summaryrefslogtreecommitdiff
path: root/MdePkg/Library/DxePcdLib/DxePcdLib.c
blob: 4f552ebb0b219f32b418e7cca92b867f75303aef (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
/** @file
Implementation of PcdLib class library for DXE phase.

Copyright (c) 2006, Intel Corporation<BR>
All rights reserved. This program and the accompanying materials                          
are licensed and made available under the terms and conditions of the BSD License         
which accompanies this distribution.  The full text of the license may be found at        
http://opensource.org/licenses/bsd-license.php                                            
                                                                                          
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.             


**/


#include <PiDxe.h>

#include <Protocol/Pcd.h>

#include <Library/PcdLib.h>
#include <Library/DebugLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/BaseMemoryLib.h>

PCD_PROTOCOL  *mPcd = NULL;


/**
  The constructor function caches the PCD_PROTOCOL pointer.

  @param[in] ImageHandle The firmware allocated handle for the EFI image.  
  @param[in] SystemTable A pointer to the EFI System Table.
  
  @retval EFI_SUCCESS The constructor always return EFI_SUCCESS.

**/
EFI_STATUS
EFIAPI
PcdLibConstructor (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS  Status;

  //
  // PCD protocol has not been installed, but a module needs to access a
  // dynamic PCD entry.
  // 
  Status = gBS->LocateProtocol (&gPcdProtocolGuid, NULL, (VOID **)&mPcd);
  ASSERT_EFI_ERROR (Status);
  ASSERT (mPcd!= NULL);

  return Status;
}


/**
  Sets the current SKU in the PCD database to the value specified by SkuId.  SkuId is returned.
  If SkuId is not less than PCD_MAX_SKU_ID, then ASSERT().
  
  @param[in]  SkuId     System SKU ID. The SKU value that will be used when the PCD service will retrieve and 
                        set values.

  @return Return the SKU ID that just be set.

**/
UINTN
EFIAPI
LibPcdSetSku (
  IN UINTN  SkuId
  )
{
  ASSERT (SkuId < PCD_MAX_SKU_ID);

  mPcd->SetSku (SkuId);

  return SkuId;
}



/**
  Returns the 8-bit value for the token specified by TokenNumber. 

  @param[in]  TokenNumber   The PCD token number to retrieve a current value for.

  @return Returns the 8-bit value for the token specified by TokenNumber. 

**/
UINT8
EFIAPI
LibPcdGet8 (
  IN UINTN             TokenNumber
  )
{
  return mPcd->Get8 (TokenNumber);
}



/**
  Returns the 16-bit value for the token specified by TokenNumber. 

  @param[in]  TokenNumber   The PCD token number to retrieve a current value for.

  @return Returns the 16-bit value for the token specified by TokenNumber. 

**/
UINT16
EFIAPI
LibPcdGet16 (
  IN UINTN             TokenNumber
  )
{
  return mPcd->Get16 (TokenNumber);
}



/**
  Returns the 32-bit value for the token specified by TokenNumber. 

  @param[in]  TokenNumber The PCD token number to retrieve a current value for.

  @return Returns the 32-bit value for the token specified by TokenNumber.

**/
UINT32
EFIAPI
LibPcdGet32 (
  IN UINTN             TokenNumber
  )
{
  return mPcd->Get32 (TokenNumber);
}



/**
  Returns the 64-bit value for the token specified by TokenNumber.

  @param[in]  TokenNumber The PCD token number to retrieve a current value for.

  @return Returns the 64-bit value for the token specified by TokenNumber.

**/
UINT64
EFIAPI
LibPcdGet64 (
  IN UINTN             TokenNumber
  )
{
  return mPcd->Get64 (TokenNumber);
}



/**
  Returns the pointer to the buffer of the token specified by TokenNumber.

  @param[in]  TokenNumber The PCD token number to retrieve a current value for.

  @return Returns the pointer to the token specified by TokenNumber.

**/
VOID *
EFIAPI
LibPcdGetPtr (
  IN UINTN             TokenNumber
  )
{
  return mPcd->GetPtr (TokenNumber);
}



/**
  Returns the Boolean value of the token specified by TokenNumber. 

  @param[in]  TokenNumber The PCD token number to retrieve a current value for.

  @return Returns the Boolean value of the token specified by TokenNumber. 

**/
BOOLEAN 
EFIAPI
LibPcdGetBool (
  IN UINTN             TokenNumber
  )
{
  return mPcd->GetBool (TokenNumber);
}



/**
  Returns the size of the token specified by TokenNumber. 

  @param[in]  TokenNumber The PCD token number to retrieve a current value for.

  @return Returns the size of the token specified by TokenNumber. 

**/
UINTN
EFIAPI
LibPcdGetSize (
  IN UINTN             TokenNumber
  )
{
  return mPcd->GetSize (TokenNumber);
}



/**
  Returns the 8-bit value for the token specified by TokenNumber and Guid.
  If Guid is NULL, then ASSERT(). 

  @param[in]  Guid Pointer to a 128-bit unique value that designates 
              which namespace to retrieve a value from.
  @param[in]  TokenNumber The PCD token number to retrieve a current value for.

  @return Return the UINT8.

**/
UINT8
EFIAPI
LibPcdGetEx8 (
  IN CONST GUID        *Guid,
  IN UINTN             TokenNumber
  )
{
  ASSERT (Guid != NULL);
  
  return mPcd->Get8Ex (Guid, TokenNumber);
}


/**
  Returns the 16-bit value for the token specified by TokenNumber and Guid.
  If Guid is NULL, then ASSERT(). 

  @param[in]  Guid Pointer to a 128-bit unique value that designates 
              which namespace to retrieve a value from.
  @param[in]  TokenNumber The PCD token number to retrieve a current value for.

  @return Return the UINT16.

**/
UINT16
EFIAPI
LibPcdGetEx16 (
  IN CONST GUID        *Guid,
  IN UINTN             TokenNumber
  )
{
  ASSERT (Guid != NULL);

  return mPcd->Get16Ex (Guid, TokenNumber);
}


/**
  Returns the 32-bit value for the token specified by TokenNumber and Guid.
  If Guid is NULL, then ASSERT(). 

  @param[in]  Guid Pointer to a 128-bit unique value that designates 
              which namespace to retrieve a value from.
  @param[in]  TokenNumber The PCD token number to retrieve a current value for.

  @return Return the UINT32.

**/
UINT32
EFIAPI
LibPcdGetEx32 (
  IN CONST GUID        *Guid,
  IN UINTN             TokenNumber
  )
{
  ASSERT (Guid != NULL);

  return mPcd->Get32Ex (Guid, TokenNumber);
}



/**
  Returns the 64-bit value for the token specified by TokenNumber and Guid.
  If Guid is NULL, then ASSERT(). 

  @param[in]  Guid Pointer to a 128-bit unique value that designates 
              which namespace to retrieve a value from.
  @param[in]  TokenNumber The PCD token number to retrieve a current value for.

  @return Return the UINT64.

**/
UINT64
EFIAPI
LibPcdGetEx64 (
  IN CONST GUID        *Guid,
  IN UINTN             TokenNumber
  )
{
  ASSERT (Guid != NULL);
  
  return mPcd->Get64Ex (Guid, TokenNumber);
}



/**
  Returns the pointer to the token specified by TokenNumber and Guid.
  If Guid is NULL, then ASSERT(). 

  @param[in]  Guid Pointer to a 128-bit unique value that designates 
              which namespace to retrieve a value from.
  @param[in]  TokenNumber The PCD token number to retrieve a current value for.

  @return Return the VOID* pointer.

**/
VOID *
EFIAPI
LibPcdGetExPtr (
  IN CONST GUID        *Guid,
  IN UINTN             TokenNumber
  )
{
  ASSERT (Guid != NULL);

  return mPcd->GetPtrEx (Guid, TokenNumber);
}



/**
  Returns the Boolean value of the token specified by TokenNumber and Guid. 
  If Guid is NULL, then ASSERT(). 

  @param[in]  Guid Pointer to a 128-bit unique value that designates 
              which namespace to retrieve a value from.
  @param[in]  TokenNumber The PCD token number to retrieve a current value for.

  @return Return the BOOLEAN.

**/
BOOLEAN
EFIAPI
LibPcdGetExBool (
  IN CONST GUID        *Guid,
  IN UINTN             TokenNumber
  )
{
  ASSERT (Guid != NULL);

  return mPcd->GetBoolEx (Guid, TokenNumber);
}



/**
  Returns the size of the token specified by TokenNumber and Guid. 
  If Guid is NULL, then ASSERT(). 

  @param[in]  Guid Pointer to a 128-bit unique value that designates 
              which namespace to retrieve a value from.
  @param[in]  TokenNumber The PCD token number to retrieve a current value for.

  @return Return the size.

**/
UINTN
EFIAPI
LibPcdGetExSize (
  IN CONST GUID        *Guid,
  IN UINTN             TokenNumber
  )
{
  ASSERT (Guid != NULL);

  return mPcd->GetSizeEx (Guid, TokenNumber);
}



/**
  Sets the 8-bit value for the token specified by TokenNumber 
  to the value specified by Value.  Value is returned.
  If fail to set pcd value, then ASSERT_EFI_ERROR().
  
  @param[in]  TokenNumber The PCD token number to set a current value for.
  @param[in]  Value The 8-bit value to set.

  @return Return the value been set.

**/
UINT8
EFIAPI
LibPcdSet8 (
  IN UINTN             TokenNumber,
  IN UINT8             Value
  )
{
  EFI_STATUS Status;

  Status = mPcd->Set8 (TokenNumber, Value);

  ASSERT_EFI_ERROR (Status);
  
  return Value;
}



/**
  Sets the 16-bit value for the token specified by TokenNumber 
  to the value specified by Value.  Value is returned.
  If fail to set pcd value, then ASSERT_EFI_ERROR().
  
  @param[in]  TokenNumber The PCD token number to set a current value for.
  @param[in]  Value The 16-bit value to set.

  @return Return the value been set.

**/
UINT16
EFIAPI
LibPcdSet16 (
  IN UINTN             TokenNumber,
  IN UINT16            Value
  )
{
  EFI_STATUS Status;

  Status = mPcd->Set16 (TokenNumber, Value);

  ASSERT_EFI_ERROR (Status);
  
  return Value;
}



/**
  Sets the 32-bit value for the token specified by TokenNumber 
  to the value specified by Value.  Value is returned.
  If fail to set pcd value, then ASSERT_EFI_ERROR().
  
  @param[in]  TokenNumber The PCD token number to set a current value for.
  @param[in]  Value The 32-bit value to set.

  @return Return the value been set.

**/
UINT32
EFIAPI
LibPcdSet32 (
  IN UINTN             TokenNumber,
  IN UINT32             Value
  )
{
  EFI_STATUS Status;
  Status = mPcd->Set32 (TokenNumber, Value);

  ASSERT_EFI_ERROR (Status);

  return Value;
}



/**
  Sets the 64-bit value for the token specified by TokenNumber 
  to the value specified by Value.  Value is returned.
  If fail to set pcd value, then ASSERT_EFI_ERROR().
  
  @param[in]  TokenNumber The PCD token number to set a current value for.
  @param[in]  Value The 64-bit value to set.

  @return Return the value been set.

**/
UINT64
EFIAPI
LibPcdSet64 (
  IN UINTN             TokenNumber,
  IN UINT64             Value
  )
{
  EFI_STATUS Status;

  Status = mPcd->Set64 (TokenNumber, Value);

  ASSERT_EFI_ERROR (Status);

  return Value;
}



/**
  Sets a buffer for the token specified by TokenNumber to 
  the value specified by Buffer and SizeOfBuffer.  Buffer to
  be set is returned. The content of the buffer could be 
  overwritten if a Callback on SET is registered with this
  TokenNumber.
  
  If SizeOfBuffer is greater than the maximum 
  size support by TokenNumber, then set SizeOfBuffer to the 
  maximum size supported by TokenNumber and return NULL to 
  indicate that the set operation was not actually performed. 
  
  If SizeOfBuffer > 0 and Buffer is NULL, then ASSERT().
  
  @param[in]      TokenNumber   The PCD token number to set a current value for.
  @param[in, out] SizeOfBuffer  The size, in bytes, of Buffer.
                                In out, returns actual size of buff is set. 
  @param[in]      Buffer        A pointer to the buffer to set.

  @return Return the pointer for the buffer been set.

**/
VOID *
EFIAPI
LibPcdSetPtr (
  IN        UINTN             TokenNumber,
  IN OUT    UINTN             *SizeOfBuffer,
  IN        VOID              *Buffer
  )
{
  EFI_STATUS Status;

  ASSERT (SizeOfBuffer != NULL);

  if (*SizeOfBuffer > 0) {
    ASSERT (Buffer != NULL);
  }

  Status = mPcd->SetPtr (TokenNumber, SizeOfBuffer, Buffer);

  if (EFI_ERROR (Status)) {
    return NULL;
  }

  return Buffer;
}



/**
  Sets the Boolean value for the token specified by TokenNumber 
  to the value specified by Value.  Value is returned.
  If fail to set pcd value, then ASSERT_EFI_ERROR().
  
  @param[in]  TokenNumber The PCD token number to set a current value for.
  @param[in]  Value       The boolean value to set.

  @return Return the value been set.

**/
BOOLEAN
EFIAPI
LibPcdSetBool (
  IN UINTN             TokenNumber,
  IN BOOLEAN           Value
  )
{
  EFI_STATUS Status;

  Status = mPcd->SetBool (TokenNumber, Value);

  ASSERT_EFI_ERROR (Status);

  return Value;
}



/**
  Sets the 8-bit value for the token specified by TokenNumber and 
  Guid to the value specified by Value. Value is returned.
  If Guid is NULL, then ASSERT().
  If fail to set pcd value, then ASSERT_EFI_ERROR().
  
  @param[in]  Guid Pointer to a 128-bit unique value that 
              designates which namespace to set a value from.
  @param[in]  TokenNumber The PCD token number to set a current value for.
  @param[in]  Value The 8-bit value to set.

  @return Return the value been set.

**/
UINT8
EFIAPI
LibPcdSetEx8 (
  IN CONST GUID        *Guid,
  IN UINTN             TokenNumber,
  IN UINT8             Value
  )
{
  EFI_STATUS Status;

  ASSERT (Guid != NULL);

  Status = mPcd->Set8Ex (Guid, TokenNumber, Value);

  ASSERT_EFI_ERROR (Status);

  return Value;
}



/**
  Sets the 16-bit value for the token specified by TokenNumber and 
  Guid to the value specified by Value. Value is returned.
  If Guid is NULL, then ASSERT().
  If fail to set pcd value, then ASSERT_EFI_ERROR().
  
  @param[in]  Guid Pointer to a 128-bit unique value that 
              designates which namespace to set a value from.
  @param[in]  TokenNumber The PCD token number to set a current value for.
  @param[in]  Value The 16-bit value to set.

  @return Return the value been set.

**/
UINT16
EFIAPI
LibPcdSetEx16 (
  IN CONST GUID        *Guid,
  IN UINTN             TokenNumber,
  IN UINT16            Value
  )
{
  EFI_STATUS Status;

  ASSERT (Guid != NULL);

  Status = mPcd->Set16Ex (Guid, TokenNumber, Value);

  ASSERT_EFI_ERROR (Status);

  return Value;
}



/**
  Sets the 32-bit value for the token specified by TokenNumber and 
  Guid to the value specified by Value. Value is returned.
  If Guid is NULL, then ASSERT().
  If fail to set pcd value, then ASSERT_EFI_ERROR().
  
  @param[in]  Guid Pointer to a 128-bit unique value that 
              designates which namespace to set a value from.
  @param[in]  TokenNumber The PCD token number to set a current value for.
  @param[in]  Value The 32-bit value to set.

  @return Return the value been set.

**/
UINT32
EFIAPI
LibPcdSetEx32 (
  IN CONST GUID        *Guid,
  IN UINTN             TokenNumber,
  IN UINT32             Value
  )
{
  EFI_STATUS Status;

  ASSERT (Guid != NULL);

  Status = mPcd->Set32Ex (Guid, TokenNumber, Value);

  ASSERT_EFI_ERROR (Status);

  return Value;
}



/**
  Sets the 64-bit value for the token specified by TokenNumber and 
  Guid to the value specified by Value. Value is returned.
  If Guid is NULL, then ASSERT().
  
  @param[in]  Guid Pointer to a 128-bit unique value that 
              designates which namespace to set a value from.
  @param[in]  TokenNumber The PCD token number to set a current value for.
  @param[in]  Value The 64-bit value to set.

  @return Return the value been set.

**/
UINT64
EFIAPI
LibPcdSetEx64 (
  IN CONST GUID        *Guid,
  IN UINTN             TokenNumber,
  IN UINT64             Value
  )
{
  EFI_STATUS Status;

  ASSERT (Guid != NULL);

  Status = mPcd->Set64Ex (Guid, TokenNumber, Value);

  ASSERT_EFI_ERROR (Status);

  return Value;
}



/**
  Sets a buffer for the token specified by TokenNumber to the value specified by 
  Buffer and SizeOfBuffer.  Buffer is returned.  If SizeOfBuffer is greater than 
  the maximum size support by TokenNumber, then set SizeOfBuffer to the maximum size 
  supported by TokenNumber and return NULL to indicate that the set operation 
  was not actually performed. 
  
  If SizeOfBuffer > 0 and Buffer is NULL, then ASSERT().
  
  @param[in]        Guid Pointer to a 128-bit unique value that 
                    designates which namespace to set a value from.
  @param[in]        TokenNumber The PCD token number to set a current value for.
  @param[in, out]   SizeOfBuffer The size, in bytes, of Buffer.
                    In out, returns actual size of buffer is set.
  @param[in]        Buffer A pointer to the buffer to set.

  @return Return the pinter to the buffer been set.

**/
VOID *
EFIAPI
LibPcdSetExPtr (
  IN      CONST GUID        *Guid,
  IN      UINTN             TokenNumber,
  IN OUT  UINTN             *SizeOfBuffer,
  IN      VOID              *Buffer
  )
{
  EFI_STATUS  Status;

  ASSERT (Guid != NULL);

  ASSERT (SizeOfBuffer != NULL);

  if (*SizeOfBuffer > 0) {
    ASSERT (Buffer != NULL);
  }

  Status = mPcd->SetPtrEx (Guid, TokenNumber, SizeOfBuffer, Buffer);

  if (EFI_ERROR (Status)) {
    return NULL;
  }

  return Buffer;
}



/**
  Sets the Boolean value for the token specified by TokenNumber and 
  Guid to the value specified by Value. Value is returned.
  If Guid is NULL, then ASSERT().
  If fail to set pcd value, then ASSERT_EFI_ERROR().
  
  @param[in]  Guid Pointer to a 128-bit unique value that 
              designates which namespace to set a value from.
  @param[in]  TokenNumber The PCD token number to set a current value for.
  @param[in]  Value The Boolean value to set.

  @return Return the value been set.

**/
BOOLEAN
EFIAPI
LibPcdSetExBool (
  IN CONST GUID        *Guid,
  IN UINTN             TokenNumber,
  IN BOOLEAN           Value
  )
{
  EFI_STATUS Status;

  ASSERT (Guid != NULL);

  Status = mPcd->SetBoolEx (Guid, TokenNumber, Value);

  ASSERT_EFI_ERROR (Status);

  return Value;
}



/**
  When the token specified by TokenNumber and Guid is set, 
  then notification function specified by NotificationFunction is called.  
  If Guid is NULL, then the default token space is used. 
  If NotificationFunction is NULL, then ASSERT().
  If fail to set callback function, then ASSERT_EFI_ERROR().
  
  @param[in]  Guid Pointer to a 128-bit unique value that designates which 
              namespace to set a value from.  If NULL, then the default 
              token space is used.
  @param[in]  TokenNumber The PCD token number to monitor.
  @param[in]  NotificationFunction The function to call when the token 
              specified by Guid and TokenNumber is set.
**/
VOID
EFIAPI
LibPcdCallbackOnSet (
  IN CONST GUID               *Guid,       OPTIONAL
  IN UINTN                    TokenNumber,
  IN PCD_CALLBACK             NotificationFunction
  )
{
  EFI_STATUS Status;

  ASSERT (NotificationFunction != NULL);

  Status = mPcd->CallbackOnSet (Guid, TokenNumber, NotificationFunction);

  ASSERT_EFI_ERROR (Status);

  return;
}



/**
  Disable a notification function that was established with LibPcdCallbackonSet().
  If NotificationFunction is NULL, then ASSERT().
  If fail to cancel callback function, then ASSERT_EFI_ERROR().
  
  @param[in]  Guid Specify the GUID token space.
  @param[in]  TokenNumber Specify the token number.
  @param[in]  NotificationFunction The callback function to be unregistered.

**/
VOID
EFIAPI
LibPcdCancelCallback (
  IN CONST GUID               *Guid,       OPTIONAL
  IN UINTN                    TokenNumber,
  IN PCD_CALLBACK             NotificationFunction
  )
{
  EFI_STATUS Status;

  ASSERT (NotificationFunction != NULL);
    
  Status = mPcd->CancelCallback (Guid, TokenNumber, NotificationFunction);

  ASSERT_EFI_ERROR (Status);

  return;
}



/**
  Retrieves the next PCD token number from the token space specified by Guid.  
  If Guid is NULL, then the default token space is used.  If TokenNumber is 0, 
  then the first token number is returned.  Otherwise, the token number that 
  follows TokenNumber in the token space is returned.  If TokenNumber is the last 
  token number in the token space, then 0 is returned.  If TokenNumber is not 0 and 
  is not in the token space specified by Guid, then ASSERT().
  If Fail to get next token, then ASSERT_EFI_ERROR().

  @param[in]  Guid        Pointer to a 128-bit unique value that designates which namespace 
                          to set a value from.  If NULL, then the default token space is used.
  @param[in]  TokenNumber The previous PCD token number.  If 0, then retrieves the first PCD 
                          token number.

  @return The next valid token number.

**/
UINTN                      
EFIAPI
LibPcdGetNextToken (
  IN CONST GUID             *Guid, OPTIONAL
  IN       UINTN            TokenNumber
  )
{
  EFI_STATUS Status;

  Status = mPcd->GetNextToken (Guid, &TokenNumber);

  ASSERT_EFI_ERROR (Status);

  return TokenNumber;
}



/**
  Used to retrieve the list of available PCD token space GUIDs.
  
  Retrieves the next PCD token space from a token space specified by Guid.
  Guid of NULL is reserved to mark the default local token namespace on the current
  platform. If Guid is NULL, then the GUID of the first non-local token space of the 
  current platform is returned. If Guid is the last non-local token space, 
  then NULL is returned. 

  If Guid is not NULL and is not a valid token space in the current platform, then ASSERT().
  If fail to get next token space, then ASSERT_EFI_ERROR().
  
  @param[in]  Guid  Pointer to a 128-bit unique value that designates from which namespace 
                    to start the search.

  @return The next valid token namespace.

**/
GUID *           
EFIAPI
LibPcdGetNextTokenSpace (
  IN CONST GUID  *TokenSpaceGuid
  )
{
  EFI_STATUS Status;

  Status = mPcd->GetNextTokenSpace (&TokenSpaceGuid);

  ASSERT_EFI_ERROR (Status);

  return (GUID *) TokenSpaceGuid;
}


/**
  Sets the PCD entry specified by PatchVariable to the value specified by Buffer 
  and SizeOfBuffer.  Buffer is returned.  If SizeOfBuffer is greater than 
  MaximumDatumSize, then set SizeOfBuffer to MaximumDatumSize and return 
  NULL to indicate that the set operation was not actually performed.  
  If SizeOfBuffer is set to MAX_ADDRESS, then SizeOfBuffer must be set to 
  MaximumDatumSize and NULL must be returned.
  
  If PatchVariable is NULL, then ASSERT().
  If SizeOfBuffer is NULL, then ASSERT().
  If SizeOfBuffer > 0 and Buffer is NULL, then ASSERT().

  @param[in] PatchVariable      A pointer to the global variable in a module that is 
                                the target of the set operation.
  @param[in] MaximumDatumSize   The maximum size allowed for the PCD entry specified by PatchVariable.
  @param[in, out] SizeOfBuffer  A pointer to the size, in bytes, of Buffer.
                                In out, returns actual size of buffer is set.
  @param[in] Buffer             A pointer to the buffer to used to set the target variable.

  @return Return the pinter to the buffer been set.
  @retval NULL   If SizeOfBuffer is set to MAX_ADDRESS or larger than MaximumDatumSize, 
                 then SizeOfBuffer must be set to MaximumDatumSize and NULL must be returned.
**/
VOID *
EFIAPI
LibPatchPcdSetPtr (
  IN        VOID        *PatchVariable,
  IN        UINTN       MaximumDatumSize,
  IN OUT    UINTN       *SizeOfBuffer,
  IN CONST  VOID        *Buffer
  )
{
  ASSERT (PatchVariable != NULL);
  ASSERT (SizeOfBuffer  != NULL);
  
  if (*SizeOfBuffer > 0) {
    ASSERT (Buffer != NULL);
  }

  if ((*SizeOfBuffer > MaximumDatumSize) ||
      (*SizeOfBuffer == MAX_ADDRESS)) {
    *SizeOfBuffer = MaximumDatumSize;
    return NULL;
  }
    
  CopyMem (PatchVariable, Buffer, *SizeOfBuffer);
  
  return (VOID *) Buffer;
}