boot/freeldr/freeldr/include/cache.h

   1 /*
   2  *  FreeLoader
   3  *  Copyright (C) 1998-2003  Brian Palmer  <brianp@sginet.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License along
  16  *  with this program; if not, write to the Free Software Foundation, Inc.,
  17  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20
  21 #pragma once
  22
  23 ///////////////////////////////////////////////////////////////////////////////////////
  24 //
  25 // This structure describes a cached block element. The disk is divided up into
  26 // cache blocks. For disks which LBA is not supported each block is the size of
  27 // one track. This will force the cache manager to make track sized reads, and
  28 // therefore maximizes throughput. For disks which support LBA the block size
  29 // is 64k because they have no cylinder, head, or sector boundaries.
  30 //
  31 ///////////////////////////////////////////////////////////////////////////////////////
  32 typedef struct
  33 {
  34         LIST_ENTRY      ListEntry;                                      // Doubly linked list synchronization member
  35
  36         ULONG                   BlockNumber;                            // Track index for CHS, 64k block index for LBA
  37         BOOLEAN         LockedInCache;                          // Indicates that this block is locked in cache memory
  38         ULONG                   AccessCount;                            // Access count for this block
  39
  40         PVOID           BlockData;                                      // Pointer to block data
  41
  42 } CACHE_BLOCK, *PCACHE_BLOCK;
  43
  44 ///////////////////////////////////////////////////////////////////////////////////////
  45 //
  46 // This structure describes a cached drive. It contains the BIOS drive number
  47 // and indicates whether or not LBA is supported. If LBA is not supported then
  48 // the drive's geometry is described here.
  49 //
  50 ///////////////////////////////////////////////////////////////////////////////////////
  51 typedef struct
  52 {
  53         UCHAR                   DriveNumber;
  54         ULONG                   BytesPerSector;
  55
  56         ULONG                   BlockSize;                      // Block size (in sectors)
  57         LIST_ENTRY              CacheBlockHead;                 // Contains CACHE_BLOCK structures
  58
  59 } CACHE_DRIVE, *PCACHE_DRIVE;
  60
  61
  62 ///////////////////////////////////////////////////////////////////////////////////////
  63 //
  64 // Internal data
  65 //
  66 ///////////////////////////////////////////////////////////////////////////////////////
  67 extern  CACHE_DRIVE             CacheManagerDrive;
  68 extern  BOOLEAN                 CacheManagerInitialized;
  69 extern  ULONG                           CacheBlockCount;
  70 extern  ULONG                           CacheSizeLimit;
  71 extern  ULONG                           CacheSizeCurrent;
  72
  73 ///////////////////////////////////////////////////////////////////////////////////////
  74 //
  75 // Internal functions
  76 //
  77 ///////////////////////////////////////////////////////////////////////////////////////
  78 PCACHE_BLOCK    CacheInternalGetBlockPointer(PCACHE_DRIVE CacheDrive, ULONG BlockNumber);                               // Returns a pointer to a CACHE_BLOCK structure given a block number
  79 PCACHE_BLOCK    CacheInternalFindBlock(PCACHE_DRIVE CacheDrive, ULONG BlockNumber);                                     // Searches the block list for a particular block
  80 PCACHE_BLOCK    CacheInternalAddBlockToCache(PCACHE_DRIVE CacheDrive, ULONG BlockNumber);                               // Adds a block to the cache's block list
  81 BOOLEAN                 CacheInternalFreeBlock(PCACHE_DRIVE CacheDrive);                                                                        // Removes a block from the cache's block list & frees the memory
  82 VOID                    CacheInternalCheckCacheSizeLimits(PCACHE_DRIVE CacheDrive);                                                     // Checks the cache size limits to see if we can add a new block, if not calls CacheInternalFreeBlock()
  83 VOID                    CacheInternalDumpBlockList(PCACHE_DRIVE CacheDrive);                                                            // Dumps the list of cached blocks to the debug output port
  84 VOID                    CacheInternalOptimizeBlockList(PCACHE_DRIVE CacheDrive, PCACHE_BLOCK CacheBlock);       // Moves the specified block to the head of the list
  85
  86
  87 BOOLEAN CacheInitializeDrive(UCHAR DriveNumber);
  88 VOID    CacheInvalidateCacheData(VOID);
  89 BOOLEAN CacheReadDiskSectors(UCHAR DiskNumber, ULONGLONG StartSector, ULONG SectorCount, PVOID Buffer);
  90 BOOLEAN CacheForceDiskSectorsIntoCache(UCHAR DiskNumber, ULONGLONG StartSector, ULONG SectorCount);
  91 BOOLEAN CacheReleaseMemory(ULONG MinimumAmountToRelease);