/* $NetBSD: isadma.c,v 1.1.1.1 1997/03/14 02:40:32 perry Exp $ */ /* from: NetBSD:dev/isa/isadma.c */ #include #include #include #include "isadmavar.h" #define IO_DMA1 0x000 /* 8237A DMA Controller #1 */ #define IO_DMA2 0x0C0 /* 8237A DMA Controller #2 */ #define DMA37MD_CASCADE 0xc0 /* cascade mode */ #define DMA1_SMSK (IO_DMA1 + 1*10) /* single mask register */ #define DMA1_MODE (IO_DMA1 + 1*11) /* mode register */ #define DMA2_SMSK (IO_DMA2 + 2*10) /* single mask register */ #define DMA2_MODE (IO_DMA2 + 2*11) /* mode register */ /* * isa_dmacascade(): program 8237 DMA controller channel to accept * external dma control by a board. */ void isa_dmacascade(chan) int chan; { #ifdef ISADMA_DEBUG if (chan < 0 || chan > 7) panic("isa_dmacascade: impossible request"); #endif /* set dma channel mode, and set dma channel mode */ if ((chan & 4) == 0) { outb(DMA1_MODE, chan | DMA37MD_CASCADE); outb(DMA1_SMSK, chan); } else { chan &= 3; outb(DMA2_MODE, chan | DMA37MD_CASCADE); outb(DMA2_SMSK, chan); } }