LXR linux/arch/arm/include/asm/dma.h

   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 < (0x10000000 - PAGE_OFFSET) ? \
  14                (PAGE_OFFSET + arm_dma_zone_size) : 0xffffffffUL; })
  15#endif
  16
  17#ifdef CONFIG_ISA_DMA_API
  18/*
  19 * This is used to support drivers written for the x86 ISA DMA API.
  20 * It should not be re-used except for that purpose.
  21 */
  22#include <linux/spinlock.h>
  23#include <linux/scatterlist.h>
  24
  25#include <mach/isa-dma.h>
  26
  27/*
  28 * The DMA modes reflect the settings for the ISA DMA controller
  29 */
  30#define DMA_MODE_MASK    0xcc
  31
  32#define DMA_MODE_READ    0x44
  33#define DMA_MODE_WRITE   0x48
  34#define DMA_MODE_CASCADE 0xc0
  35#define DMA_AUTOINIT     0x10
  36
  37extern raw_spinlock_t  dma_spin_lock;
  38
  39static inline unsigned long claim_dma_lock(void)
  40{
  41        unsigned long flags;
  42        raw_spin_lock_irqsave(&dma_spin_lock, flags);
  43        return flags;
  44}
  45
  46static inline void release_dma_lock(unsigned long flags)
  47{
  48        raw_spin_unlock_irqrestore(&dma_spin_lock, flags);
  49}
  50
  51/* Clear the 'DMA Pointer Flip Flop'.
  52 * Write 0 for LSB/MSB, 1 for MSB/LSB access.
  53 */
  54#define clear_dma_ff(chan)
  55
  56/* Set only the page register bits of the transfer address.
  57 *
  58 * NOTE: This is an architecture specific function, and should
  59 *       be hidden from the drivers
  60 */
  61extern void set_dma_page(unsigned int chan, char pagenr);
  62
  63/* Request a DMA channel
  64 *
  65 * Some architectures may need to do allocate an interrupt
  66 */
  67extern int  request_dma(unsigned int chan, const char * device_id);
  68
  69/* Free a DMA channel
  70 *
  71 * Some architectures may need to do free an interrupt
  72 */
  73extern void free_dma(unsigned int chan);
  74
  75/* Enable DMA for this channel
  76 *
  77 * On some architectures, this may have other side effects like
  78 * enabling an interrupt and setting the DMA registers.
  79 */
  80extern void enable_dma(unsigned int chan);
  81
  82/* Disable DMA for this channel
  83 *
  84 * On some architectures, this may have other side effects like
  85 * disabling an interrupt or whatever.
  86 */
  87extern void disable_dma(unsigned int chan);
  88
  89/* Test whether the specified channel has an active DMA transfer
  90 */
  91extern int dma_channel_active(unsigned int chan);
  92
  93/* Set the DMA scatter gather list for this channel
  94 *
  95 * This should not be called if a DMA channel is enabled,
  96 * especially since some DMA architectures don't update the
  97 * DMA address immediately, but defer it to the enable_dma().
  98 */
  99extern void set_dma_sg(unsigned int chan, struct scatterlist *sg, int nr_sg);
 100
 101/* Set the DMA address for this channel
 102 *
 103 * This should not be called if a DMA channel is enabled,
 104 * especially since some DMA architectures don't update the
 105 * DMA address immediately, but defer it to the enable_dma().
 106 */
 107extern void __set_dma_addr(unsigned int chan, void *addr);
 108#define set_dma_addr(chan, addr)                                \
 109        __set_dma_addr(chan, (void *)__bus_to_virt(addr))
 110
 111/* Set the DMA byte count for this channel
 112 *
 113 * This should not be called if a DMA channel is enabled,
 114 * especially since some DMA architectures don't update the
 115 * DMA count immediately, but defer it to the enable_dma().
 116 */
 117extern void set_dma_count(unsigned int chan, unsigned long count);
 118
 119/* Set the transfer direction for this channel
 120 *
 121 * This should not be called if a DMA channel is enabled,
 122 * especially since some DMA architectures don't update the
 123 * DMA transfer direction immediately, but defer it to the
 124 * enable_dma().
 125 */
 126extern void set_dma_mode(unsigned int chan, unsigned int mode);
 127
 128/* Set the transfer speed for this channel
 129 */
 130extern void set_dma_speed(unsigned int chan, int cycle_ns);
 131
 132/* Get DMA residue count. After a DMA transfer, this
 133 * should return zero. Reading this while a DMA transfer is
 134 * still in progress will return unpredictable results.
 135 * If called before the channel has been used, it may return 1.
 136 * Otherwise, it returns the number of _bytes_ left to transfer.
 137 */
 138extern int  get_dma_residue(unsigned int chan);
 139
 140#ifndef NO_DMA
 141#define NO_DMA  255
 142#endif
 143
 144#endif /* CONFIG_ISA_DMA_API */
 145
 146#ifdef CONFIG_PCI
 147extern int isa_dma_bridge_buggy;
 148#else
 149#define isa_dma_bridge_buggy    (0)
 150#endif
 151
 152#endif /* __ASM_ARM_DMA_H */
 153