diff options
Diffstat (limited to 'arch/x86/include/asm/dma.h')
| -rw-r--r-- | arch/x86/include/asm/dma.h | 318 |
1 files changed, 318 insertions, 0 deletions
diff --git a/arch/x86/include/asm/dma.h b/arch/x86/include/asm/dma.h new file mode 100644 index 00000000000..ca1098a7e58 --- /dev/null +++ b/arch/x86/include/asm/dma.h @@ -0,0 +1,318 @@ +/* + * 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_X86_DMA_H +#define _ASM_X86_DMA_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 + +#ifdef CONFIG_X86_32 + +/* The maximum address that we can perform a DMA transfer to on this platform */ +#define MAX_DMA_ADDRESS (PAGE_OFFSET + 0x1000000) + +#else + +/* 16MB ISA DMA zone */ +#define MAX_DMA_PFN ((16 * 1024 * 1024) >> PAGE_SHIFT) + +/* 4GB broken PCI/AGP hardware bus master zone */ +#define MAX_DMA32_PFN ((4UL * 1024 * 1024 * 1024) >> PAGE_SHIFT) + +/* Compat define for old dma zone */ +#define MAX_DMA_ADDRESS ((unsigned long)__va(MAX_DMA_PFN << PAGE_SHIFT)) + +#endif + +/* 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 + +/* I/O to memory, no autoinit, increment, single mode */ +#define DMA_MODE_READ 0x44 +/* memory to I/O, no autoinit, increment, single mode */ +#define DMA_MODE_WRITE 0x48 +/* pass thru DREQ->HRQ, DACK<-HLDA only */ +#define DMA_MODE_CASCADE 0xC0 + +#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; + /* using short to get 16-bit wrap around */ + unsigned short count; + + io_port = (dmanr <= 3) ? ((dmanr & 3) << 1) + 1 + IO_DMA1_BASE + : ((dmanr & 3) << 2) + 2 + IO_DMA2_BASE; + + 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); +extern void free_dma(unsigned int dmanr); + +/* From PCI */ + +#ifdef CONFIG_PCI +extern int isa_dma_bridge_buggy; +#else +#define isa_dma_bridge_buggy (0) +#endif + +#endif /* _ASM_X86_DMA_H */ |