drivers/usb/usbehci/physmem.c

   1 /*
   2  * PROJECT:     ReactOS Universal Serial Bus Bulk Enhanced Host Controller Interface
   3  * LICENSE:     GPL - See COPYING in the top level directory
   4  * FILE:        drivers/usb/usbehci/physmem.c
   5  * PURPOSE:     Common Buffer routines.
   6  * PROGRAMMERS:
   7  *              Michael Martin (michael.martin@reactos.org)
   8  */
   9
  10 #include "physmem.h"
  11 #include "debug.h"
  12
  13 #define SMALL_ALLOCATION_SIZE 32
  14
  15 VOID
  16 DumpPages()
  17 {
  18     //PMEM_HEADER MemBlock = (PMEM_HEADER)EhciSharedMemory.VirtualAddr;
  19 }
  20
  21 // Returns Virtual Address of Allocated Memory
  22 ULONG
  23 AllocateMemory(PEHCI_HOST_CONTROLLER hcd, ULONG Size, ULONG *PhysicalAddress)
  24 {
  25     PMEM_HEADER MemoryPage = (PMEM_HEADER)hcd->CommonBufferVA;
  26     ULONG PageCount = 0;
  27     ULONG NumberOfPages = hcd->CommonBufferSize / PAGE_SIZE;
  28     ULONG BlocksNeeded;
  29     ULONG i,j, freeCount;
  30     ULONG RetAddr = 0;
  31
  32     Size = ((Size + SMALL_ALLOCATION_SIZE - 1) / SMALL_ALLOCATION_SIZE) * SMALL_ALLOCATION_SIZE;
  33     BlocksNeeded = Size / SMALL_ALLOCATION_SIZE;
  34
  35     do
  36     {
  37         if (MemoryPage->IsFull)
  38         {
  39             PageCount++;
  40             MemoryPage = (PMEM_HEADER)((ULONG)MemoryPage + PAGE_SIZE);
  41             continue;
  42         }
  43         freeCount = 0;
  44         for (i = 0; i < sizeof(MemoryPage->Entry); i++)
  45         {
  46             if (!MemoryPage->Entry[i].InUse)
  47             {
  48                 freeCount++;
  49             }
  50             else
  51             {
  52                 freeCount = 0;
  53             }
  54
  55             if (freeCount == BlocksNeeded)
  56             {
  57                 for (j = 0; j < freeCount; j++)
  58                 {
  59                     MemoryPage->Entry[i-j].InUse = 1;
  60                     MemoryPage->Entry[i-j].Blocks = 0;
  61                 }
  62
  63                 MemoryPage->Entry[i-freeCount + 1].Blocks = BlocksNeeded;
  64
  65                 RetAddr = (ULONG)MemoryPage + (SMALL_ALLOCATION_SIZE * (i - freeCount + 1)) + sizeof(MEM_HEADER);
  66
  67                 *PhysicalAddress = (ULONG)hcd->CommonBufferPA.LowPart + (RetAddr - (ULONG)hcd->CommonBufferVA);
  68                 return RetAddr;
  69             }
  70         }
  71
  72         PageCount++;
  73         MemoryPage = (PMEM_HEADER)((ULONG)MemoryPage + PAGE_SIZE);
  74     } while (PageCount < NumberOfPages);
  75
  76     return 0;
  77 }
  78
  79 VOID
  80 ReleaseMemory(ULONG Address)
  81 {
  82     PMEM_HEADER MemoryPage;
  83     ULONG Index, i;
  84
  85     MemoryPage = (PMEM_HEADER)(Address & ~(PAGE_SIZE - 1));
  86
  87     Index = (Address - ((ULONG)MemoryPage + sizeof(MEM_HEADER))) / SMALL_ALLOCATION_SIZE;
  88
  89     for (i = 0; i < MemoryPage->Entry[Index].Blocks; i++)
  90     {
  91         MemoryPage->Entry[Index + i].InUse = 0;
  92         MemoryPage->Entry[Index + i].Blocks = 0;
  93     }
  94 }