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/* $Id: dma.h,v 1.7 1992/12/14 00:29:34 root Exp root $ * 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. */ #ifndef _ASM_DMA_H #define _ASM_DMA_H #include <linux/config.h> #include <linux/spinlock.h> /* And spinlocks */ #include <asm/io.h> /* need byte IO */ #include <linux/delay.h> #ifdef HAVE_REALLY_SLOW_DMA_CONTROLLER #define dma_outb outb_p #else #define dma_outb outb #endif #define dma_inb inb /* * NOTES about DMA transfers: * * controller 1: channels 0-3, byte operations, ports 00-1F * controller 2: channels 4-7, word operations, ports C0-DF * * - ALL registers are 8 bits only, regardless of transfer size * - channel 4 is not used - cascades 1 into 2. * - channels 0-3 are byte - addresses/counts are for physical bytes * - channels 5-7 are word - addresses/counts are for physical words * - transfers must not cross physical 64K (0-3) or 128K (5-7) boundaries * - transfer count loaded to registers is 1 less than actual count * - controller 2 offsets are all even (2x offsets for controller 1) * - page registers for 5-7 don't use data bit 0, represent 128K pages * - page registers for 0-3 use bit 0, represent 64K pages * * DMA transfers are limited to the lower 16MB of _physical_ memory. * Note that addresses loaded into registers must be _physical_ addresses, * not logical addresses (which may differ if paging is active). * * Address mapping for channels 0-3: * * A23 ... A16 A15 ... A8 A7 ... A0 (Physical addresses) * | ... | | ... | | ... | * | ... | | ... | | ... | * | ... | | ... | | ... | * P7 ... P0 A7 ... A0 A7 ... A0 * | Page | Addr MSB | Addr LSB | (DMA registers) * * Address mapping for channels 5-7: * * A23 ... A17 A16 A15 ... A9 A8 A7 ... A1 A0 (Physical addresses) * | ... | \ \ ... \ \ \ ... \ \ * | ... | \ \ ... \ \ \ ... \ (not used) * | ... | \ \ ... \ \ \ ... \ * P7 ... P1 (0) A7 A6 ... A0 A7 A6 ... A0 * | Page | Addr MSB | Addr LSB | (DMA registers) * * Again, channels 5-7 transfer _physical_ words (16 bits), so addresses * and counts _must_ be word-aligned (the lowest address bit is _ignored_ at * the hardware level, so odd-byte transfers aren't possible). * * Transfer count (_not # bytes_) is limited to 64K, represented as actual * count - 1 : 64K => 0xFFFF, 1 => 0x0000. Thus, count is always 1 or more, * and up to 128K bytes may be transferred on channels 5-7 in one operation. * */ #define MAX_DMA_CHANNELS 8 /* The maximum address that we can perform a DMA transfer to on this platform */ #define MAX_DMA_ADDRESS (PAGE_OFFSET+0x1000000) /* 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 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 DMA_ADDR_0 0x00 /* DMA address registers */ #define DMA_ADDR_1 0x02 #define DMA_ADDR_2 0x04 #define DMA_ADDR_3 0x06 #define DMA_ADDR_4 0xC0 #define DMA_ADDR_5 0xC4 #define DMA_ADDR_6 0xC8 #define DMA_ADDR_7 0xCC #define DMA_CNT_0 0x01 /* DMA count registers */ #define DMA_CNT_1 0x03 #define DMA_CNT_2 0x05 #define DMA_CNT_3 0x07 #define DMA_CNT_4 0xC2 #define DMA_CNT_5 0xC6 #define DMA_CNT_6 0xCA #define DMA_CNT_7 0xCE #define DMA_PAGE_0 0x87 /* DMA page registers */ #define DMA_PAGE_1 0x83 #define DMA_PAGE_2 0x81 #define DMA_PAGE_3 0x82 #define DMA_PAGE_5 0x8B #define DMA_PAGE_6 0x89 #define DMA_PAGE_7 0x8A #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 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); } /* enable/disable a specific DMA channel */ static __inline__ void enable_dma(unsigned int dmanr) { if (dmanr<=3) dma_outb(dmanr, DMA1_MASK_REG); else dma_outb(dmanr & 3, DMA2_MASK_REG); } static __inline__ void disable_dma(unsigned int dmanr) { if (dmanr<=3) dma_outb(dmanr | 4, DMA1_MASK_REG); else dma_outb((dmanr & 3) | 4, DMA2_MASK_REG); } /* 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) { if (dmanr<=3) dma_outb(0, DMA1_CLEAR_FF_REG); else dma_outb(0, DMA2_CLEAR_FF_REG); } /* set mode (above) for a specific DMA channel */ static __inline__ void set_dma_mode(unsigned int dmanr, char mode) { if (dmanr<=3) dma_outb(mode | dmanr, DMA1_MODE_REG); else dma_outb(mode | (dmanr&3), DMA2_MODE_REG); } /* 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) { switch(dmanr) { case 0: dma_outb(pagenr, DMA_PAGE_0); break; case 1: dma_outb(pagenr, DMA_PAGE_1); break; case 2: dma_outb(pagenr, DMA_PAGE_2); break; case 3: dma_outb(pagenr, DMA_PAGE_3); break; case 5: dma_outb(pagenr & 0xfe, DMA_PAGE_5); break; case 6: dma_outb(pagenr & 0xfe, DMA_PAGE_6); break; case 7: dma_outb(pagenr & 0xfe, DMA_PAGE_7); break; } } /* 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_dma_page(dmanr, a>>16); if (dmanr <= 3) { dma_outb( a & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE ); dma_outb( (a>>8) & 0xff, ((dmanr&3)<<1) + IO_DMA1_BASE ); } else { dma_outb( (a>>1) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE ); dma_outb( (a>>9) & 0xff, ((dmanr&3)<<2) + IO_DMA2_BASE ); } } /* Set transfer size (max 64k for DMA0..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) { count--; if (dmanr <= 3) { dma_outb( count & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE ); dma_outb( (count>>8) & 0xff, ((dmanr&3)<<1) + 1 + IO_DMA1_BASE ); } else { dma_outb( (count>>1) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE ); dma_outb( (count>>9) & 0xff, ((dmanr&3)<<2) + 2 + IO_DMA2_BASE ); } } /* 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); } /* These are in kernel/dma.c: */ extern int request_dma(unsigned int dmanr, const char * device_id); /* reserve a DMA channel */ extern void free_dma(unsigned int dmanr); /* release it again */ /* From PCI */ #ifdef CONFIG_PCI extern int isa_dma_bridge_buggy; #else #define isa_dma_bridge_buggy (0) #endif #endif /* _ASM_DMA_H */