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

   1#ifndef __ASM_ARM_DMA_H
   2#define __ASM_ARM_DMA_H
   3
   4/*
   5 * This is the maximum virtual address which can be DMA'd from.
   6 */
   7#ifndef CONFIG_ZONE_DMA
   8#define MAX_DMA_ADDRESS 0xffffffffUL
   9#else
  10#define MAX_DMA_ADDRESS ({ \
  11        extern phys_addr_t arm_dma_zone_size; \
  12        arm_dma_zone_size && arm_dma_zone_size < (0x10000000 - PAGE_OFFSET) ? \
  13                (PAGE_OFFSET + arm_dma_zone_size) : 0xffffffffUL; })
  14#endif
  15
  16#ifdef CONFIG_ISA_DMA_API
  17/*
  18 * This is used to support drivers written for the x86 ISA DMA API.
  19 * It should not be re-used except for that purpose.
  20 */
  21#include <linux/spinlock.h>
  22#include <linux/scatterlist.h>
  23
  24#include <mach/isa-dma.h>
  25
  26/*
  27 * The DMA modes reflect the settings for the ISA DMA controller
  28 */
  29#define DMA_MODE_MASK    0xcc
  30
  31#define DMA_MODE_READ    0x44
  32#define DMA_MODE_WRITE   0x48
  33#define DMA_MODE_CASCADE 0xc0
  34#define DMA_AUTOINIT     0x10
  35
  36extern raw_spinlock_t  dma_spin_lock;
  37
  38static inline unsigned long claim_dma_lock(void)
  39{
  40        unsigned long flags;
  41        raw_spin_lock_irqsave(&dma_spin_lock, flags);
  42        return flags;
  43}
  44
  45static inline void release_dma_lock(unsigned long flags)
  46{
  47        raw_spin_unlock_irqrestore(&dma_spin_lock, flags);
  48}
  49
  50/* Clear the 'DMA Pointer Flip Flop'.
  51 * Write 0 for LSB/MSB, 1 for MSB/LSB access.
  52 */
  53#define clear_dma_ff(chan)
  54
  55/* Set only the page register bits of the transfer address.
  56 *
  57 * NOTE: This is an architecture specific function, and should
  58 *       be hidden from the drivers
  59 */
  60extern void set_dma_page(unsigned int chan, char pagenr);
  61
  62/* Request a DMA channel
  63 *
  64 * Some architectures may need to do allocate an interrupt
  65 */
  66extern int  request_dma(unsigned int chan, const char * device_id);
  67
  68/* Free a DMA channel
  69 *
  70 * Some architectures may need to do free an interrupt
  71 */
  72extern void free_dma(unsigned int chan);
  73
  74/* Enable DMA for this channel
  75 *
  76 * On some architectures, this may have other side effects like
  77 * enabling an interrupt and setting the DMA registers.
  78 */
  79extern void enable_dma(unsigned int chan);
  80
  81/* Disable DMA for this channel
  82 *
  83 * On some architectures, this may have other side effects like
  84 * disabling an interrupt or whatever.
  85 */
  86extern void disable_dma(unsigned int chan);
  87
  88/* Test whether the specified channel has an active DMA transfer
  89 */
  90extern int dma_channel_active(unsigned int chan);
  91
  92/* Set the DMA scatter gather list for this channel
  93 *
  94 * This should not be called if a DMA channel is enabled,
  95 * especially since some DMA architectures don't update the
  96 * DMA address immediately, but defer it to the enable_dma().
  97 */
  98extern void set_dma_sg(unsigned int chan, struct scatterlist *sg, int nr_sg);
  99
 100/* Set the DMA address for this channel
 101 *
 102 * This should not be called if a DMA channel is enabled,
 103 * especially since some DMA architectures don't update the
 104 * DMA address immediately, but defer it to the enable_dma().
 105 */
 106extern void __set_dma_addr(unsigned int chan, void *addr);
 107#define set_dma_addr(chan, addr)                                \
 108        __set_dma_addr(chan, (void *)__bus_to_virt(addr))
 109
 110/* Set the DMA byte count for this channel
 111 *
 112 * This should not be called if a DMA channel is enabled,
 113 * especially since some DMA architectures don't update the
 114 * DMA count immediately, but defer it to the enable_dma().
 115 */
 116extern void set_dma_count(unsigned int chan, unsigned long count);
 117
 118/* Set the transfer direction for this channel
 119 *
 120 * This should not be called if a DMA channel is enabled,
 121 * especially since some DMA architectures don't update the
 122 * DMA transfer direction immediately, but defer it to the
 123 * enable_dma().
 124 */
 125extern void set_dma_mode(unsigned int chan, unsigned int mode);
 126
 127/* Set the transfer speed for this channel
 128 */
 129extern void set_dma_speed(unsigned int chan, int cycle_ns);
 130
 131/* Get DMA residue count. After a DMA transfer, this
 132 * should return zero. Reading this while a DMA transfer is
 133 * still in progress will return unpredictable results.
 134 * If called before the channel has been used, it may return 1.
 135 * Otherwise, it returns the number of _bytes_ left to transfer.
 136 */
 137extern int  get_dma_residue(unsigned int chan);
 138
 139#ifndef NO_DMA
 140#define NO_DMA  255
 141#endif
 142
 143#endif /* CONFIG_ISA_DMA_API */
 144
 145#ifdef CONFIG_PCI
 146extern int isa_dma_bridge_buggy;
 147#else
 148#define isa_dma_bridge_buggy    (0)
 149#endif
 150
 151#endif /* __ASM_ARM_DMA_H */
 152