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 unsigned long arm_dma_zone_size; \
  12         arm_dma_zone_size ? \
  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 <asm/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
  36 extern raw_spinlock_t  dma_spin_lock;
  37
  38 static 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
  45 static 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  */
  60 extern 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  */
  66 extern 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  */
  72 extern 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  */
  79 extern 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  */
  86 extern void disable_dma(unsigned int chan);
  87
  88 /* Test whether the specified channel has an active DMA transfer
  89  */
  90 extern 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  */
  98 extern 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  */
 106 extern 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  */
 116 extern 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  */
 125 extern void set_dma_mode(unsigned int chan, unsigned int mode);
 126
 127 /* Set the transfer speed for this channel
 128  */
 129 extern 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  */
 137 extern 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
 146 extern int isa_dma_bridge_buggy;
 147 #else
 148 #define isa_dma_bridge_buggy    (0)
 149 #endif
 150
 151 #endif /* __ASM_ARM_DMA_H */