1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef __ASM_ARM_DMA_H 3#define __ASM_ARM_DMA_H 4 5/* 6 * This is the maximum virtual address which can be DMA'd from. 7 */ 8#ifndef CONFIG_ZONE_DMA 9#define MAX_DMA_ADDRESS 0xffffffffUL 10#else 11#define MAX_DMA_ADDRESS ({ \ 12 extern phys_addr_t arm_dma_zone_size; \ 13 arm_dma_zone_size && arm_dma_zone_size < (0x100000000ULL - PAGE_OFFSET) ? \ 14 (PAGE_OFFSET + arm_dma_zone_size) : 0xffffffffUL; }) 15 16extern phys_addr_t arm_dma_limit; 17#define ARCH_LOW_ADDRESS_LIMIT arm_dma_limit 18#endif 19 20#ifdef CONFIG_ISA_DMA_API 21/* 22 * This is used to support drivers written for the x86 ISA DMA API. 23 * It should not be re-used except for that purpose. 24 */ 25#include <linux/spinlock.h> 26#include <linux/scatterlist.h> 27 28#include <mach/isa-dma.h> 29 30/* 31 * The DMA modes reflect the settings for the ISA DMA controller 32 */ 33#define DMA_MODE_MASK 0xcc 34 35#define DMA_MODE_READ 0x44 36#define DMA_MODE_WRITE 0x48 37#define DMA_MODE_CASCADE 0xc0 38#define DMA_AUTOINIT 0x10 39 40extern raw_spinlock_t dma_spin_lock; 41 42static inline unsigned long claim_dma_lock(void) 43{ 44 unsigned long flags; 45 raw_spin_lock_irqsave(&dma_spin_lock, flags); 46 return flags; 47} 48 49static inline void release_dma_lock(unsigned long flags) 50{ 51 raw_spin_unlock_irqrestore(&dma_spin_lock, flags); 52} 53 54/* Clear the 'DMA Pointer Flip Flop'. 55 * Write 0 for LSB/MSB, 1 for MSB/LSB access. 56 */ 57#define clear_dma_ff(chan) 58 59/* Set only the page register bits of the transfer address. 60 * 61 * NOTE: This is an architecture specific function, and should 62 * be hidden from the drivers 63 */ 64extern void set_dma_page(unsigned int chan, char pagenr); 65 66/* Request a DMA channel 67 * 68 * Some architectures may need to do allocate an interrupt 69 */ 70extern int request_dma(unsigned int chan, const char * device_id); 71 72/* Free a DMA channel 73 * 74 * Some architectures may need to do free an interrupt 75 */ 76extern void free_dma(unsigned int chan); 77 78/* Enable DMA for this channel 79 * 80 * On some architectures, this may have other side effects like 81 * enabling an interrupt and setting the DMA registers. 82 */ 83extern void enable_dma(unsigned int chan); 84 85/* Disable DMA for this channel 86 * 87 * On some architectures, this may have other side effects like 88 * disabling an interrupt or whatever. 89 */ 90extern void disable_dma(unsigned int chan); 91 92/* Test whether the specified channel has an active DMA transfer 93 */ 94extern int dma_channel_active(unsigned int chan); 95 96/* Set the DMA scatter gather list for this channel 97 * 98 * This should not be called if a DMA channel is enabled, 99 * especially since some DMA architectures don't update the 100 * DMA address immediately, but defer it to the enable_dma(). 101 */ 102extern void set_dma_sg(unsigned int chan, struct scatterlist *sg, int nr_sg); 103 104/* Set the DMA address for this channel 105 * 106 * This should not be called if a DMA channel is enabled, 107 * especially since some DMA architectures don't update the 108 * DMA address immediately, but defer it to the enable_dma(). 109 */ 110extern void __set_dma_addr(unsigned int chan, void *addr); 111#define set_dma_addr(chan, addr) \ 112 __set_dma_addr(chan, (void *)isa_bus_to_virt(addr)) 113 114/* Set the DMA byte count for this channel 115 * 116 * This should not be called if a DMA channel is enabled, 117 * especially since some DMA architectures don't update the 118 * DMA count immediately, but defer it to the enable_dma(). 119 */ 120extern void set_dma_count(unsigned int chan, unsigned long count); 121 122/* Set the transfer direction for this channel 123 * 124 * This should not be called if a DMA channel is enabled, 125 * especially since some DMA architectures don't update the 126 * DMA transfer direction immediately, but defer it to the 127 * enable_dma(). 128 */ 129extern void set_dma_mode(unsigned int chan, unsigned int mode); 130 131/* Set the transfer speed for this channel 132 */ 133extern void set_dma_speed(unsigned int chan, int cycle_ns); 134 135/* Get DMA residue count. After a DMA transfer, this 136 * should return zero. Reading this while a DMA transfer is 137 * still in progress will return unpredictable results. 138 * If called before the channel has been used, it may return 1. 139 * Otherwise, it returns the number of _bytes_ left to transfer. 140 */ 141extern int get_dma_residue(unsigned int chan); 142 143#ifndef NO_DMA 144#define NO_DMA 255 145#endif 146 147#endif /* CONFIG_ISA_DMA_API */ 148 149#endif /* __ASM_ARM_DMA_H */ 150