123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116 |
- /*
- * include/asm-alpha/dma.h
- *
- * This is essentially the same as the i386 DMA stuff, as the AlphaPCs
- * use ISA-compatible dma. The only extension is support for high-page
- * registers that allow to set the top 8 bits of a 32-bit DMA address.
- * This register should be written last when setting up a DMA address
- * as this will also enable DMA across 64 KB boundaries.
- */
- /* $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/spinlock.h>
- #include <asm/io.h>
- #define dma_outb outb
- #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
- /*
- ISA DMA limitations on Alpha platforms,
- These may be due to SIO (PCI<->ISA bridge) chipset limitation, or
- just a wiring limit.
- */
- /* The maximum address for ISA DMA transfer on Alpha XL, due to an
- hardware SIO limitation, is 64MB.
- */
- #define ALPHA_XL_MAX_ISA_DMA_ADDRESS 0x04000000UL
- /* The maximum address for ISA DMA transfer on RUFFIAN,
- due to an hardware SIO limitation, is 16MB.
- */
- #define ALPHA_RUFFIAN_MAX_ISA_DMA_ADDRESS 0x01000000UL
- /* The maximum address for ISA DMA transfer on SABLE, and some ALCORs,
- due to an hardware SIO chip limitation, is 2GB.
- */
- #define ALPHA_SABLE_MAX_ISA_DMA_ADDRESS 0x80000000UL
- #define ALPHA_ALCOR_MAX_ISA_DMA_ADDRESS 0x80000000UL
- /*
- Maximum address for all the others is the complete 32-bit bus
- address space.
- */
- #define ALPHA_MAX_ISA_DMA_ADDRESS 0x100000000UL
- #ifdef CONFIG_ALPHA_GENERIC
- # define MAX_ISA_DMA_ADDRESS (alpha_mv.max_isa_dma_address)
- #else
- # if defined(CONFIG_ALPHA_XL)
- # define MAX_ISA_DMA_ADDRESS ALPHA_XL_MAX_ISA_DMA_ADDRESS
- # elif defined(CONFIG_ALPHA_RUFFIAN)
- # define MAX_ISA_DMA_ADDRESS ALPHA_RUFFIAN_MAX_ISA_DMA_ADDRESS
- # elif defined(CONFIG_ALPHA_SABLE)
- # define MAX_ISA_DMA_ADDRESS ALPHA_SABLE_MAX_ISA_DMA_ADDRESS
- # elif defined(CONFIG_ALPHA_ALCOR)
- # define MAX_ISA_DMA_ADDRESS ALPHA_ALCOR_MAX_ISA_DMA_ADDRESS
|