/* $Id: dma.h,v 1.2 1999/04/27 00:46:18 deller Exp $ * linux/include/asm/dma.h: Defines for using and allocating dma channels. * Written by Hennus Bergman, 1992. * High DMA channel support & info by Hannu Savolainen * and John Boyd, Nov. 1992. * (c) Copyright 2000, Grant Grundler */ #ifndef _ASM_DMA_H #define _ASM_DMA_H #include <linux/config.h> #include <asm/io.h> /* need byte IO */ #include <asm/system.h> #define dma_outb outb #define dma_inb inb /* ** DMA_CHUNK_SIZE is used by the SCSI mid-layer to break up ** (or rather not merge) DMA's into managable chunks. ** On parisc, this is more of the software/tuning constraint ** rather than the HW. I/O MMU allocation alogorithms can be ** faster with smaller size is (to some degree). */ #define DMA_CHUNK_SIZE (BITS_PER_LONG*PAGE_SIZE) /* The maximum address that we can perform a DMA transfer to on this platform ** New dynamic DMA interfaces should obsolete this.... */ #define MAX_DMA_ADDRESS (~0UL) /* ** We don't have DMA channels... well V-class does but the ** Dynamic DMA Mapping interface will support them... right? :^) ** Note: this is not relevant right now for PA-RISC, but we cannot ** leave this as undefined because some things (e.g. sound) ** won't compile :-( */ #define MAX_DMA_CHANNELS 8 #define DMA_MODE_READ 0x44 /* I/O to memory, no autoinit, increment, single mode */ #define DMA_MODE_WRITE 0x48 /* memory to I/O, no autoinit, increment, single mode */ #define DMA_MODE_CASCADE 0xC0 /* pass thru DREQ->HRQ, DACK<-HLDA only */ #define DMA_AUTOINIT 0x10 /* 8237 DMA controllers */ #define IO_DMA1_BASE 0x00 /* 8 bit slave DMA, channels 0..3 */ #define IO_DMA2_BASE 0xC0 /* 16 bit master DMA, ch 4(=slave input)..7 */ /* DMA controller registers */ #define DMA1_CMD_REG 0x08 /* command register (w) */ #define DMA1_STAT_REG 0x08 /* status register (r) */ #define DMA1_REQ_REG 0x09 /* request register (w) */ #define DMA1_MASK_REG 0x0A /* single-channel mask (w) */ #define DMA1_MODE_REG 0x0B /* mode register (w) */ #define DMA1_CLEAR_FF_REG 0x0C /* clear pointer flip-flop (w) */ #define DMA1_TEMP_REG 0x0D /* Temporary Register (r) */ #define DMA1_RESET_REG 0x0D /* Master Clear (w) */ #define DMA1_CLR_MASK_REG 0x0E /* Clear Mask */ #define DMA1_MASK_ALL_REG 0x0F /* all-channels mask (w) */ #define DMA1_EXT_MODE_REG (0x400 | DMA1_MODE_REG) #define DMA2_CMD_REG 0xD0 /* command register (w) */ #define DMA2_STAT_REG 0xD0 /* status register (r) */ #define DMA2_REQ_REG 0xD2 /* request register (w) */ #define DMA2_MASK_REG 0xD4 /* single-channel mask (w) */ #define DMA2_MODE_REG 0xD6 /* mode register (w) */ #define DMA2_CLEAR_FF_REG 0xD8 /* clear pointer flip-flop (w) */ #define DMA2_TEMP_REG 0xDA /* Temporary Register (r) */ #define DMA2_RESET_REG 0xDA /* Master Clear (w) */ #define DMA2_CLR_MASK_REG 0xDC /* Clear Mask */ #define DMA2_MASK_ALL_REG 0xDE /* all-channels mask (w) */ #define DMA2_EXT_MODE_REG (0x400 | DMA2_MODE_REG) extern spinlock_t dma_spin_lock; static __inline__ unsigned long claim_dma_lock(void) { unsigned long flags; spin_lock_irqsave(&dma_spin_lock, flags); return flags; } static __inline__ void release_dma_lock(unsigned long flags) { spin_unlock_irqrestore(&dma_spin_lock, flags); } /* Get DMA residue count. After a DMA transfer, this * should return zero. Reading this while a DMA transfer is * still in progress will return unpredictable results. * If called before the channel has been used, it may return 1. * Otherwise, it returns the number of _bytes_ left to transfer. * * Assumes DMA flip-flop is clear. */ static __inline__ int get_dma_residue(unsigned int dmanr) { unsigned int io_port = (dmanr<=3)? ((dmanr&3)<<1) + 1 + IO_DMA1_BASE : ((dmanr&3)<<2) + 2 + IO_DMA2_BASE; /* using short to get 16-bit wrap around */ unsigned short count; count = 1 + dma_inb(io_port); count += dma_inb(io_port) << 8; return (dmanr<=3)? count : (count<<1); } /* enable/disable a specific DMA channel */ static __inline__ void enable_dma(unsigned int dmanr) { #ifdef CONFIG_SUPERIO if (dmanr<=3) dma_outb(dmanr, DMA1_MASK_REG); else dma_outb(dmanr & 3, DMA2_MASK_REG); #endif } static __inline__ void disable_dma(unsigned int dmanr) { #ifdef CONFIG_SUPERIO if (dmanr<=3) dma_outb(dmanr | 4, DMA1_MASK_REG); else dma_outb((dmanr & 3) | 4, DMA2_MASK_REG); #endif } /* reserve a DMA channel */ #define request_dma(dmanr, device_id) (0) /* Clear the 'DMA Pointer Flip Flop'. * Write 0 for LSB/MSB, 1 for MSB/LSB access. * Use this once to initialize the FF to a known state. * After that, keep track of it. :-) * --- In order to do that, the DMA routines below should --- * --- only be used while holding the DMA lock ! --- */ static __inline__ void clear_dma_ff(unsigned int dmanr) { } /* set mode (above) for a specific DMA channel */ static __inline__ void set_dma_mode(unsigned int dmanr, char mode) { } /* Set only the page register bits of the transfer address. * This is used for successive transfers when we know the contents of * the lower 16 bits of the DMA current address register, but a 64k boundary * may have been crossed. */ static __inline__ void set_dma_page(unsigned int dmanr, char pagenr) { } /* Set transfer address & page bits for specific DMA channel. * Assumes dma flipflop is clear. */ static __inline__ void set_dma_addr(unsigned int dmanr, unsigned int a) { } /* Set transfer size (max 64k for DMA1..3, 128k for DMA5..7) for * a specific DMA channel. * You must ensure the parameters are valid. * NOTE: from a manual: "the number of transfers is one more * than the initial word count"! This is taken into account. * Assumes dma flip-flop is clear. * NOTE 2: "count" represents _bytes_ and must be even for channels 5-7. */ static __inline__ void set_dma_count(unsigned int dmanr, unsigned int count) { } #define free_dma(dmanr) #ifdef CONFIG_PCI extern int isa_dma_bridge_buggy; #else #define isa_dma_bridge_buggy (0) #endif #endif /* _ASM_DMA_H */