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