arch/arm/include/asm/dma.h

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