workbench/devs/AHI/Drivers/EMU10kx/emuadxmg.c

   1
   2 /*
   3  **********************************************************************
   4  *     emuadxmg.c - Address space manager for emu10k1 driver
   5  *     Copyright 1999, 2000 Creative Labs, Inc.
   6  *
   7  **********************************************************************
   8  *
   9  *     Date                 Author          Summary of changes
  10  *     ----                 ------          ------------------
  11  *     October 20, 1999     Bertrand Lee    base code release
  12  *
  13  **********************************************************************
  14  *
  15  *     This program is free software; you can redistribute it and/or
  16  *     modify it under the terms of the GNU General Public License as
  17  *     published by the Free Software Foundation; either version 2 of
  18  *     the License, or (at your option) any later version.
  19  *
  20  *     This program is distributed in the hope that it will be useful,
  21  *     but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  *     GNU General Public License for more details.
  24  *
  25  *     You should have received a copy of the GNU General Public
  26  *     License along with this program; if not, write to the Free
  27  *     Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139,
  28  *     USA.
  29  *
  30  **********************************************************************
  31  */
  32
  33 #ifdef AHI
  34 #include <config.h>
  35 #endif
  36
  37 #include "hwaccess.h"
  38
  39 /* Allocates emu address space */
  40
  41 int emu10k1_addxmgr_alloc(u32 size, struct emu10k1_card *card)
  42 {
  43         u16 *pagetable = card->emupagetable;
  44         u16 index = 0;
  45         u16 numpages;
  46 #ifndef AHI
  47         unsigned long flags;
  48 #endif
  49
  50         /* Convert bytes to pages */
  51         numpages = (size / EMUPAGESIZE) + ((size % EMUPAGESIZE) ? 1 : 0);
  52
  53         spin_lock_irqsave(&card->lock, flags);
  54
  55         while (index < (MAXPAGES - 1)) {
  56                 if (pagetable[index] & 0x8000) {
  57                         /* This block of pages is in use, jump to the start of the next block. */
  58                         index += (pagetable[index] & 0x7fff);
  59                 } else {
  60                         /* Found free block */
  61                         if (pagetable[index] >= numpages) {
  62
  63                                 /* Block is large enough */
  64
  65                                 /* If free block is larger than the block requested
  66                                  * then adjust the size of the block remaining */
  67                                 if (pagetable[index] > numpages)
  68                                         pagetable[index + numpages] = pagetable[index] - numpages;
  69
  70                                 pagetable[index] = (numpages | 0x8000); /* Mark block as used */
  71
  72                                 spin_unlock_irqrestore(&card->lock, flags);
  73
  74                                 return index;
  75                         } else {
  76                                 /* Block too small, jump to the start of the next block */
  77                                 index += pagetable[index];
  78                         }
  79                 }
  80         }
  81
  82         spin_unlock_irqrestore(&card->lock, flags);
  83
  84         return -1;
  85 }
  86
  87 /* Frees a previously allocated emu address space. */
  88
  89 void emu10k1_addxmgr_free(struct emu10k1_card *card, int index)
  90 {
  91         u16 *pagetable = card->emupagetable;
  92         u16 origsize = 0;
  93 #ifndef AHI
  94         unsigned long flags;
  95 #endif
  96
  97         spin_lock_irqsave(&card->lock, flags);
  98
  99         if (pagetable[index] & 0x8000) {
 100                 /* Block is allocated - mark block as free */
 101                 origsize = pagetable[index] & 0x7fff;
 102                 pagetable[index] = origsize;
 103
 104                 /* If next block is free, we concat both blocks */
 105                 if (!(pagetable[index + origsize] & 0x8000))
 106                         pagetable[index] += pagetable[index + origsize] & 0x7fff;
 107         }
 108
 109         spin_unlock_irqrestore(&card->lock, flags);
 110
 111         return;
 112 }