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      1 /** @file
      2 
      3   Routine procedures for memory allocate/free.
      4 
      5 Copyright (c) 2013 - 2015, Intel Corporation. All rights reserved.<BR>
      6 This program and the accompanying materials
      7 are licensed and made available under the terms and conditions of the BSD License
      8 which accompanies this distribution.  The full text of the license may be found at
      9 http://opensource.org/licenses/bsd-license.php
     10 
     11 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
     12 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
     13 
     14 **/
     15 
     16 
     17 #include "Xhci.h"
     18 
     19 
     20 /**
     21   Allocate a block of memory to be used by the buffer pool.
     22 
     23   @param  Pool           The buffer pool to allocate memory for.
     24   @param  Pages          How many pages to allocate.
     25 
     26   @return The allocated memory block or NULL if failed.
     27 
     28 **/
     29 USBHC_MEM_BLOCK *
     30 UsbHcAllocMemBlock (
     31   IN  USBHC_MEM_POOL      *Pool,
     32   IN  UINTN               Pages
     33   )
     34 {
     35   USBHC_MEM_BLOCK         *Block;
     36   EFI_PCI_IO_PROTOCOL     *PciIo;
     37   VOID                    *BufHost;
     38   VOID                    *Mapping;
     39   EFI_PHYSICAL_ADDRESS    MappedAddr;
     40   UINTN                   Bytes;
     41   EFI_STATUS              Status;
     42 
     43   PciIo = Pool->PciIo;
     44 
     45   Block = AllocateZeroPool (sizeof (USBHC_MEM_BLOCK));
     46   if (Block == NULL) {
     47     return NULL;
     48   }
     49 
     50   //
     51   // each bit in the bit array represents USBHC_MEM_UNIT
     52   // bytes of memory in the memory block.
     53   //
     54   ASSERT (USBHC_MEM_UNIT * 8 <= EFI_PAGE_SIZE);
     55 
     56   Block->BufLen   = EFI_PAGES_TO_SIZE (Pages);
     57   Block->BitsLen  = Block->BufLen / (USBHC_MEM_UNIT * 8);
     58   Block->Bits     = AllocateZeroPool (Block->BitsLen);
     59 
     60   if (Block->Bits == NULL) {
     61     gBS->FreePool (Block);
     62     return NULL;
     63   }
     64 
     65   //
     66   // Allocate the number of Pages of memory, then map it for
     67   // bus master read and write.
     68   //
     69   Status = PciIo->AllocateBuffer (
     70                     PciIo,
     71                     AllocateAnyPages,
     72                     EfiBootServicesData,
     73                     Pages,
     74                     &BufHost,
     75                     0
     76                     );
     77 
     78   if (EFI_ERROR (Status)) {
     79     goto FREE_BITARRAY;
     80   }
     81 
     82   Bytes = EFI_PAGES_TO_SIZE (Pages);
     83   Status = PciIo->Map (
     84                     PciIo,
     85                     EfiPciIoOperationBusMasterCommonBuffer,
     86                     BufHost,
     87                     &Bytes,
     88                     &MappedAddr,
     89                     &Mapping
     90                     );
     91 
     92   if (EFI_ERROR (Status) || (Bytes != EFI_PAGES_TO_SIZE (Pages))) {
     93     goto FREE_BUFFER;
     94   }
     95 
     96   Block->BufHost  = BufHost;
     97   Block->Buf      = (UINT8 *) ((UINTN) MappedAddr);
     98   Block->Mapping  = Mapping;
     99 
    100   return Block;
    101 
    102 FREE_BUFFER:
    103   PciIo->FreeBuffer (PciIo, Pages, BufHost);
    104 
    105 FREE_BITARRAY:
    106   gBS->FreePool (Block->Bits);
    107   gBS->FreePool (Block);
    108   return NULL;
    109 }
    110 
    111 
    112 /**
    113   Free the memory block from the memory pool.
    114 
    115   @param  Pool           The memory pool to free the block from.
    116   @param  Block          The memory block to free.
    117 
    118 **/
    119 VOID
    120 UsbHcFreeMemBlock (
    121   IN USBHC_MEM_POOL       *Pool,
    122   IN USBHC_MEM_BLOCK      *Block
    123   )
    124 {
    125   EFI_PCI_IO_PROTOCOL     *PciIo;
    126 
    127   ASSERT ((Pool != NULL) && (Block != NULL));
    128 
    129   PciIo = Pool->PciIo;
    130 
    131   //
    132   // Unmap the common buffer then free the structures
    133   //
    134   PciIo->Unmap (PciIo, Block->Mapping);
    135   PciIo->FreeBuffer (PciIo, EFI_SIZE_TO_PAGES (Block->BufLen), Block->BufHost);
    136 
    137   gBS->FreePool (Block->Bits);
    138   gBS->FreePool (Block);
    139 }
    140 
    141 
    142 /**
    143   Alloc some memory from the block.
    144 
    145   @param  Block          The memory block to allocate memory from.
    146   @param  Units          Number of memory units to allocate.
    147 
    148   @return The pointer to the allocated memory. If couldn't allocate the needed memory,
    149           the return value is NULL.
    150 
    151 **/
    152 VOID *
    153 UsbHcAllocMemFromBlock (
    154   IN  USBHC_MEM_BLOCK     *Block,
    155   IN  UINTN               Units
    156   )
    157 {
    158   UINTN                   Byte;
    159   UINT8                   Bit;
    160   UINTN                   StartByte;
    161   UINT8                   StartBit;
    162   UINTN                   Available;
    163   UINTN                   Count;
    164 
    165   ASSERT ((Block != 0) && (Units != 0));
    166 
    167   StartByte  = 0;
    168   StartBit   = 0;
    169   Available  = 0;
    170 
    171   for (Byte = 0, Bit = 0; Byte < Block->BitsLen;) {
    172     //
    173     // If current bit is zero, the corresponding memory unit is
    174     // available, otherwise we need to restart our searching.
    175     // Available counts the consective number of zero bit.
    176     //
    177     if (!USB_HC_BIT_IS_SET (Block->Bits[Byte], Bit)) {
    178       Available++;
    179 
    180       if (Available >= Units) {
    181         break;
    182       }
    183 
    184       NEXT_BIT (Byte, Bit);
    185 
    186     } else {
    187       NEXT_BIT (Byte, Bit);
    188 
    189       Available  = 0;
    190       StartByte  = Byte;
    191       StartBit   = Bit;
    192     }
    193   }
    194 
    195   if (Available < Units) {
    196     return NULL;
    197   }
    198 
    199   //
    200   // Mark the memory as allocated
    201   //
    202   Byte  = StartByte;
    203   Bit   = StartBit;
    204 
    205   for (Count = 0; Count < Units; Count++) {
    206     ASSERT (!USB_HC_BIT_IS_SET (Block->Bits[Byte], Bit));
    207 
    208     Block->Bits[Byte] = (UINT8) (Block->Bits[Byte] | USB_HC_BIT (Bit));
    209     NEXT_BIT (Byte, Bit);
    210   }
    211 
    212   return Block->BufHost + (StartByte * 8 + StartBit) * USBHC_MEM_UNIT;
    213 }
    214 
    215 /**
    216   Calculate the corresponding pci bus address according to the Mem parameter.
    217 
    218   @param  Pool           The memory pool of the host controller.
    219   @param  Mem            The pointer to host memory.
    220   @param  Size           The size of the memory region.
    221 
    222   @return                The pci memory address
    223 
    224 **/
    225 EFI_PHYSICAL_ADDRESS
    226 UsbHcGetPciAddrForHostAddr (
    227   IN USBHC_MEM_POOL       *Pool,
    228   IN VOID                 *Mem,
    229   IN UINTN                Size
    230   )
    231 {
    232   USBHC_MEM_BLOCK         *Head;
    233   USBHC_MEM_BLOCK         *Block;
    234   UINTN                   AllocSize;
    235   EFI_PHYSICAL_ADDRESS    PhyAddr;
    236   UINTN                   Offset;
    237 
    238   Head      = Pool->Head;
    239   AllocSize = USBHC_MEM_ROUND (Size);
    240 
    241   if (Mem == NULL) {
    242     return 0;
    243   }
    244 
    245   for (Block = Head; Block != NULL; Block = Block->Next) {
    246     //
    247     // scan the memory block list for the memory block that
    248     // completely contains the allocated memory.
    249     //
    250     if ((Block->BufHost <= (UINT8 *) Mem) && (((UINT8 *) Mem + AllocSize) <= (Block->BufHost + Block->BufLen))) {
    251       break;
    252     }
    253   }
    254 
    255   ASSERT ((Block != NULL));
    256   //
    257   // calculate the pci memory address for host memory address.
    258   //
    259   Offset = (UINT8 *)Mem - Block->BufHost;
    260   PhyAddr = (EFI_PHYSICAL_ADDRESS)(UINTN) (Block->Buf + Offset);
    261   return PhyAddr;
    262 }
    263 
    264 /**
    265   Calculate the corresponding host address according to the pci address.
    266 
    267   @param  Pool           The memory pool of the host controller.
    268   @param  Mem            The pointer to pci memory.
    269   @param  Size           The size of the memory region.
    270 
    271   @return                The host memory address
    272 
    273 **/
    274 EFI_PHYSICAL_ADDRESS
    275 UsbHcGetHostAddrForPciAddr (
    276   IN USBHC_MEM_POOL       *Pool,
    277   IN VOID                 *Mem,
    278   IN UINTN                Size
    279   )
    280 {
    281   USBHC_MEM_BLOCK         *Head;
    282   USBHC_MEM_BLOCK         *Block;
    283   UINTN                   AllocSize;
    284   EFI_PHYSICAL_ADDRESS    HostAddr;
    285   UINTN                   Offset;
    286 
    287   Head      = Pool->Head;
    288   AllocSize = USBHC_MEM_ROUND (Size);
    289 
    290   if (Mem == NULL) {
    291     return 0;
    292   }
    293 
    294   for (Block = Head; Block != NULL; Block = Block->Next) {
    295     //
    296     // scan the memory block list for the memory block that
    297     // completely contains the allocated memory.
    298     //
    299     if ((Block->Buf <= (UINT8 *) Mem) && (((UINT8 *) Mem + AllocSize) <= (Block->Buf + Block->BufLen))) {
    300       break;
    301     }
    302   }
    303 
    304   ASSERT ((Block != NULL));
    305   //
    306   // calculate the pci memory address for host memory address.
    307   //
    308   Offset = (UINT8 *)Mem - Block->Buf;
    309   HostAddr = (EFI_PHYSICAL_ADDRESS)(UINTN) (Block->BufHost + Offset);
    310   return HostAddr;
    311 }
    312 
    313 /**
    314   Insert the memory block to the pool's list of the blocks.
    315 
    316   @param  Head           The head of the memory pool's block list.
    317   @param  Block          The memory block to insert.
    318 
    319 **/
    320 VOID
    321 UsbHcInsertMemBlockToPool (
    322   IN USBHC_MEM_BLOCK      *Head,
    323   IN USBHC_MEM_BLOCK      *Block
    324   )
    325 {
    326   ASSERT ((Head != NULL) && (Block != NULL));
    327   Block->Next = Head->Next;
    328   Head->Next  = Block;
    329 }
    330 
    331 
    332 /**
    333   Is the memory block empty?
    334 
    335   @param  Block   The memory block to check.
    336 
    337   @retval TRUE    The memory block is empty.
    338   @retval FALSE   The memory block isn't empty.
    339 
    340 **/
    341 BOOLEAN
    342 UsbHcIsMemBlockEmpty (
    343   IN USBHC_MEM_BLOCK     *Block
    344   )
    345 {
    346   UINTN                   Index;
    347 
    348   for (Index = 0; Index < Block->BitsLen; Index++) {
    349     if (Block->Bits[Index] != 0) {
    350       return FALSE;
    351     }
    352   }
    353 
    354   return TRUE;
    355 }
    356 
    357 
    358 /**
    359   Unlink the memory block from the pool's list.
    360 
    361   @param  Head           The block list head of the memory's pool.
    362   @param  BlockToUnlink  The memory block to unlink.
    363 
    364 **/
    365 VOID
    366 UsbHcUnlinkMemBlock (
    367   IN USBHC_MEM_BLOCK      *Head,
    368   IN USBHC_MEM_BLOCK      *BlockToUnlink
    369   )
    370 {
    371   USBHC_MEM_BLOCK         *Block;
    372 
    373   ASSERT ((Head != NULL) && (BlockToUnlink != NULL));
    374 
    375   for (Block = Head; Block != NULL; Block = Block->Next) {
    376     if (Block->Next == BlockToUnlink) {
    377       Block->Next         = BlockToUnlink->Next;
    378       BlockToUnlink->Next = NULL;
    379       break;
    380     }
    381   }
    382 }
    383 
    384 
    385 /**
    386   Initialize the memory management pool for the host controller.
    387 
    388   @param  PciIo                The PciIo that can be used to access the host controller.
    389 
    390   @retval EFI_SUCCESS          The memory pool is initialized.
    391   @retval EFI_OUT_OF_RESOURCE  Fail to init the memory pool.
    392 
    393 **/
    394 USBHC_MEM_POOL *
    395 UsbHcInitMemPool (
    396   IN EFI_PCI_IO_PROTOCOL  *PciIo
    397   )
    398 {
    399   USBHC_MEM_POOL          *Pool;
    400 
    401   Pool = AllocatePool (sizeof (USBHC_MEM_POOL));
    402 
    403   if (Pool == NULL) {
    404     return Pool;
    405   }
    406 
    407   Pool->PciIo   = PciIo;
    408   Pool->Head    = UsbHcAllocMemBlock (Pool, USBHC_MEM_DEFAULT_PAGES);
    409 
    410   if (Pool->Head == NULL) {
    411     gBS->FreePool (Pool);
    412     Pool = NULL;
    413   }
    414 
    415   return Pool;
    416 }
    417 
    418 
    419 /**
    420   Release the memory management pool.
    421 
    422   @param  Pool              The USB memory pool to free.
    423 
    424   @retval EFI_SUCCESS       The memory pool is freed.
    425   @retval EFI_DEVICE_ERROR  Failed to free the memory pool.
    426 
    427 **/
    428 EFI_STATUS
    429 UsbHcFreeMemPool (
    430   IN USBHC_MEM_POOL       *Pool
    431   )
    432 {
    433   USBHC_MEM_BLOCK *Block;
    434 
    435   ASSERT (Pool->Head != NULL);
    436 
    437   //
    438   // Unlink all the memory blocks from the pool, then free them.
    439   // UsbHcUnlinkMemBlock can't be used to unlink and free the
    440   // first block.
    441   //
    442   for (Block = Pool->Head->Next; Block != NULL; Block = Pool->Head->Next) {
    443     UsbHcUnlinkMemBlock (Pool->Head, Block);
    444     UsbHcFreeMemBlock (Pool, Block);
    445   }
    446 
    447   UsbHcFreeMemBlock (Pool, Pool->Head);
    448   gBS->FreePool (Pool);
    449   return EFI_SUCCESS;
    450 }
    451 
    452 
    453 /**
    454   Allocate some memory from the host controller's memory pool
    455   which can be used to communicate with host controller.
    456 
    457   @param  Pool           The host controller's memory pool.
    458   @param  Size           Size of the memory to allocate.
    459 
    460   @return The allocated memory or NULL.
    461 
    462 **/
    463 VOID *
    464 UsbHcAllocateMem (
    465   IN  USBHC_MEM_POOL      *Pool,
    466   IN  UINTN               Size
    467   )
    468 {
    469   USBHC_MEM_BLOCK         *Head;
    470   USBHC_MEM_BLOCK         *Block;
    471   USBHC_MEM_BLOCK         *NewBlock;
    472   VOID                    *Mem;
    473   UINTN                   AllocSize;
    474   UINTN                   Pages;
    475 
    476   Mem       = NULL;
    477   AllocSize = USBHC_MEM_ROUND (Size);
    478   Head      = Pool->Head;
    479   ASSERT (Head != NULL);
    480 
    481   //
    482   // First check whether current memory blocks can satisfy the allocation.
    483   //
    484   for (Block = Head; Block != NULL; Block = Block->Next) {
    485     Mem = UsbHcAllocMemFromBlock (Block, AllocSize / USBHC_MEM_UNIT);
    486 
    487     if (Mem != NULL) {
    488       ZeroMem (Mem, Size);
    489       break;
    490     }
    491   }
    492 
    493   if (Mem != NULL) {
    494     return Mem;
    495   }
    496 
    497   //
    498   // Create a new memory block if there is not enough memory
    499   // in the pool. If the allocation size is larger than the
    500   // default page number, just allocate a large enough memory
    501   // block. Otherwise allocate default pages.
    502   //
    503   if (AllocSize > EFI_PAGES_TO_SIZE (USBHC_MEM_DEFAULT_PAGES)) {
    504     Pages = EFI_SIZE_TO_PAGES (AllocSize) + 1;
    505   } else {
    506     Pages = USBHC_MEM_DEFAULT_PAGES;
    507   }
    508 
    509   NewBlock = UsbHcAllocMemBlock (Pool, Pages);
    510 
    511   if (NewBlock == NULL) {
    512     DEBUG ((EFI_D_ERROR, "UsbHcAllocateMem: failed to allocate block\n"));
    513     return NULL;
    514   }
    515 
    516   //
    517   // Add the new memory block to the pool, then allocate memory from it
    518   //
    519   UsbHcInsertMemBlockToPool (Head, NewBlock);
    520   Mem = UsbHcAllocMemFromBlock (NewBlock, AllocSize / USBHC_MEM_UNIT);
    521 
    522   if (Mem != NULL) {
    523     ZeroMem (Mem, Size);
    524   }
    525 
    526   return Mem;
    527 }
    528 
    529 
    530 /**
    531   Free the allocated memory back to the memory pool.
    532 
    533   @param  Pool           The memory pool of the host controller.
    534   @param  Mem            The memory to free.
    535   @param  Size           The size of the memory to free.
    536 
    537 **/
    538 VOID
    539 UsbHcFreeMem (
    540   IN USBHC_MEM_POOL       *Pool,
    541   IN VOID                 *Mem,
    542   IN UINTN                Size
    543   )
    544 {
    545   USBHC_MEM_BLOCK         *Head;
    546   USBHC_MEM_BLOCK         *Block;
    547   UINT8                   *ToFree;
    548   UINTN                   AllocSize;
    549   UINTN                   Byte;
    550   UINTN                   Bit;
    551   UINTN                   Count;
    552 
    553   Head      = Pool->Head;
    554   AllocSize = USBHC_MEM_ROUND (Size);
    555   ToFree    = (UINT8 *) Mem;
    556 
    557   for (Block = Head; Block != NULL; Block = Block->Next) {
    558     //
    559     // scan the memory block list for the memory block that
    560     // completely contains the memory to free.
    561     //
    562     if ((Block->BufHost <= ToFree) && ((ToFree + AllocSize) <= (Block->BufHost + Block->BufLen))) {
    563       //
    564       // compute the start byte and bit in the bit array
    565       //
    566       Byte  = ((ToFree - Block->BufHost) / USBHC_MEM_UNIT) / 8;
    567       Bit   = ((ToFree - Block->BufHost) / USBHC_MEM_UNIT) % 8;
    568 
    569       //
    570       // reset associated bits in bit arry
    571       //
    572       for (Count = 0; Count < (AllocSize / USBHC_MEM_UNIT); Count++) {
    573         ASSERT (USB_HC_BIT_IS_SET (Block->Bits[Byte], Bit));
    574 
    575         Block->Bits[Byte] = (UINT8) (Block->Bits[Byte] ^ USB_HC_BIT (Bit));
    576         NEXT_BIT (Byte, Bit);
    577       }
    578 
    579       break;
    580     }
    581   }
    582 
    583   //
    584   // If Block == NULL, it means that the current memory isn't
    585   // in the host controller's pool. This is critical because
    586   // the caller has passed in a wrong memory point
    587   //
    588   ASSERT (Block != NULL);
    589 
    590   //
    591   // Release the current memory block if it is empty and not the head
    592   //
    593   if ((Block != Head) && UsbHcIsMemBlockEmpty (Block)) {
    594     UsbHcUnlinkMemBlock (Head, Block);
    595     UsbHcFreeMemBlock (Pool, Block);
    596   }
    597 
    598   return ;
    599 }
    600 
    601 /**
    602   Allocates pages at a specified alignment that are suitable for an EfiPciIoOperationBusMasterCommonBuffer mapping.
    603 
    604   If Alignment is not a power of two and Alignment is not zero, then ASSERT().
    605 
    606   @param  PciIo                 The PciIo that can be used to access the host controller.
    607   @param  Pages                 The number of pages to allocate.
    608   @param  Alignment             The requested alignment of the allocation.  Must be a power of two.
    609   @param  HostAddress           The system memory address to map to the PCI controller.
    610   @param  DeviceAddress         The resulting map address for the bus master PCI controller to
    611                                 use to access the hosts HostAddress.
    612   @param  Mapping               A resulting value to pass to Unmap().
    613 
    614   @retval EFI_SUCCESS           Success to allocate aligned pages.
    615   @retval EFI_INVALID_PARAMETER Pages or Alignment is not valid.
    616   @retval EFI_OUT_OF_RESOURCES  Do not have enough resources to allocate memory.
    617 
    618 
    619 **/
    620 EFI_STATUS
    621 UsbHcAllocateAlignedPages (
    622   IN EFI_PCI_IO_PROTOCOL    *PciIo,
    623   IN UINTN                  Pages,
    624   IN UINTN                  Alignment,
    625   OUT VOID                  **HostAddress,
    626   OUT EFI_PHYSICAL_ADDRESS  *DeviceAddress,
    627   OUT VOID                  **Mapping
    628   )
    629 {
    630   EFI_STATUS            Status;
    631   VOID                  *Memory;
    632   UINTN                 AlignedMemory;
    633   UINTN                 AlignmentMask;
    634   UINTN                 UnalignedPages;
    635   UINTN                 RealPages;
    636   UINTN                 Bytes;
    637 
    638   //
    639   // Alignment must be a power of two or zero.
    640   //
    641   ASSERT ((Alignment & (Alignment - 1)) == 0);
    642 
    643   if ((Alignment & (Alignment - 1)) != 0) {
    644     return EFI_INVALID_PARAMETER;
    645   }
    646 
    647   if (Pages == 0) {
    648     return EFI_INVALID_PARAMETER;
    649   }
    650   if (Alignment > EFI_PAGE_SIZE) {
    651     //
    652     // Calculate the total number of pages since alignment is larger than page size.
    653     //
    654     AlignmentMask  = Alignment - 1;
    655     RealPages      = Pages + EFI_SIZE_TO_PAGES (Alignment);
    656     //
    657     // Make sure that Pages plus EFI_SIZE_TO_PAGES (Alignment) does not overflow.
    658     //
    659     ASSERT (RealPages > Pages);
    660 
    661     Status = PciIo->AllocateBuffer (
    662                       PciIo,
    663                       AllocateAnyPages,
    664                       EfiBootServicesData,
    665                       Pages,
    666                       &Memory,
    667                       0
    668                       );
    669     if (EFI_ERROR (Status)) {
    670       return EFI_OUT_OF_RESOURCES;
    671     }
    672     AlignedMemory  = ((UINTN) Memory + AlignmentMask) & ~AlignmentMask;
    673     UnalignedPages = EFI_SIZE_TO_PAGES (AlignedMemory - (UINTN) Memory);
    674     if (UnalignedPages > 0) {
    675       //
    676       // Free first unaligned page(s).
    677       //
    678       Status = PciIo->FreeBuffer (PciIo, UnalignedPages, Memory);
    679       ASSERT_EFI_ERROR (Status);
    680     }
    681     Memory         = (VOID *)(UINTN)(AlignedMemory + EFI_PAGES_TO_SIZE (Pages));
    682     UnalignedPages = RealPages - Pages - UnalignedPages;
    683     if (UnalignedPages > 0) {
    684       //
    685       // Free last unaligned page(s).
    686       //
    687       Status = PciIo->FreeBuffer (PciIo, UnalignedPages, Memory);
    688       ASSERT_EFI_ERROR (Status);
    689     }
    690   } else {
    691     //
    692     // Do not over-allocate pages in this case.
    693     //
    694     Status = PciIo->AllocateBuffer (
    695                       PciIo,
    696                       AllocateAnyPages,
    697                       EfiBootServicesData,
    698                       Pages,
    699                       &Memory,
    700                       0
    701                       );
    702     if (EFI_ERROR (Status)) {
    703       return EFI_OUT_OF_RESOURCES;
    704     }
    705     AlignedMemory  = (UINTN) Memory;
    706   }
    707 
    708   Bytes = EFI_PAGES_TO_SIZE (Pages);
    709   Status = PciIo->Map (
    710                     PciIo,
    711                     EfiPciIoOperationBusMasterCommonBuffer,
    712                     (VOID *) AlignedMemory,
    713                     &Bytes,
    714                     DeviceAddress,
    715                     Mapping
    716                     );
    717 
    718   if (EFI_ERROR (Status) || (Bytes != EFI_PAGES_TO_SIZE (Pages))) {
    719     Status = PciIo->FreeBuffer (PciIo, Pages, (VOID *) AlignedMemory);
    720     return EFI_OUT_OF_RESOURCES;
    721   }
    722 
    723   *HostAddress = (VOID *) AlignedMemory;
    724 
    725   return EFI_SUCCESS;
    726 }
    727 
    728 /**
    729   Frees memory that was allocated with UsbHcAllocateAlignedPages().
    730 
    731   @param  PciIo                 The PciIo that can be used to access the host controller.
    732   @param  HostAddress           The system memory address to map to the PCI controller.
    733   @param  Pages                 The number of 4 KB pages to free.
    734   @param  Mapping               The mapping value returned from Map().
    735 
    736 **/
    737 VOID
    738 UsbHcFreeAlignedPages (
    739   IN EFI_PCI_IO_PROTOCOL    *PciIo,
    740   IN VOID                   *HostAddress,
    741   IN UINTN                  Pages,
    742   VOID                      *Mapping
    743   )
    744 {
    745   EFI_STATUS      Status;
    746 
    747   ASSERT (Pages != 0);
    748 
    749   Status = PciIo->Unmap (PciIo, Mapping);
    750   ASSERT_EFI_ERROR (Status);
    751 
    752   Status = PciIo->FreeBuffer (
    753                     PciIo,
    754                     Pages,
    755                     HostAddress
    756                     );
    757   ASSERT_EFI_ERROR (Status);
    758 }
    759