/* * Linux DMA channel management. * Copyright (C) 1995 Shantanu Goel. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ #define MACH_INCLUDE #include #include /* * Bitmap of allocated/free DMA channels. */ static int dma_busy = 0x10; /* * Allocate a DMA channel. */ int request_dma(unsigned int drq, const char *name) { if (drq > 7) panic("request_dma: bad DRQ number"); if (dma_busy & (1 << drq)) return (-LINUX_EBUSY); dma_busy |= 1 << drq; return (0); } /* * Free a DMA channel. */ void free_dma(unsigned int drq) { if (drq > 7) panic("free_dma: bad DRQ number"); dma_busy &= ~(1 << drq); }