105 строки
3.1 KiB
C
105 строки
3.1 KiB
C
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/*
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**********************************************************************
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* emuadxmg.c - Address space manager for emu10k1 driver
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* Copyright 1999, 2000 Creative Labs, Inc.
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*
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**********************************************************************
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*
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* Date Author Summary of changes
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* ---- ------ ------------------
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* October 20, 1999 Bertrand Lee base code release
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*
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**********************************************************************
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the Free
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* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139,
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* USA.
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*
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**********************************************************************
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*/
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#include "hwaccess.h"
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/* Allocates emu address space */
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int emu10k1_addxmgr_alloc(u32 size, struct emu10k1_card *card)
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{
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u16 *pagetable = card->emupagetable;
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u16 index = 0;
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u16 numpages;
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unsigned long flags;
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/* Convert bytes to pages */
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numpages = (size / EMUPAGESIZE) + ((size % EMUPAGESIZE) ? 1 : 0);
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spin_lock_irqsave(&card->lock, flags);
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while (index < (MAXPAGES - 1)) {
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if (pagetable[index] & 0x8000) {
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/* This block of pages is in use, jump to the start of the next block. */
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index += (pagetable[index] & 0x7fff);
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} else {
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/* Found free block */
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if (pagetable[index] >= numpages) {
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/* Block is large enough */
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/* If free block is larger than the block requested
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* then adjust the size of the block remaining */
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if (pagetable[index] > numpages)
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pagetable[index + numpages] = pagetable[index] - numpages;
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pagetable[index] = (numpages | 0x8000); /* Mark block as used */
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spin_unlock_irqrestore(&card->lock, flags);
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return index;
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} else {
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/* Block too small, jump to the start of the next block */
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index += pagetable[index];
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}
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}
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}
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spin_unlock_irqrestore(&card->lock, flags);
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return -1;
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}
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/* Frees a previously allocated emu address space. */
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void emu10k1_addxmgr_free(struct emu10k1_card *card, int index)
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{
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u16 *pagetable = card->emupagetable;
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u16 origsize = 0;
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unsigned long flags;
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spin_lock_irqsave(&card->lock, flags);
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if (pagetable[index] & 0x8000) {
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/* Block is allocated - mark block as free */
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origsize = pagetable[index] & 0x7fff;
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pagetable[index] = origsize;
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/* If next block is free, we concat both blocks */
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if (!(pagetable[index + origsize] & 0x8000))
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pagetable[index] += pagetable[index + origsize] & 0x7fff;
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}
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spin_unlock_irqrestore(&card->lock, flags);
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return;
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}
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