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 typedef unsigned int dmach_t;
  23
  24 #include <mach/isa-dma.h>
  25
  26 /*
  27  * DMA modes
  28  */
  29 typedef unsigned int dmamode_t;
  30
  31 #define DMA_MODE_MASK   3
  32
  33 #define DMA_MODE_READ    0
  34 #define DMA_MODE_WRITE   1
  35 #define DMA_MODE_CASCADE 2
  36 #define DMA_AUTOINIT     4
  37
  38 extern spinlock_t  dma_spin_lock;
  39
  40 static inline unsigned long claim_dma_lock(void)
  41 {
  42         unsigned long flags;
  43         spin_lock_irqsave(&dma_spin_lock, flags);
  44         return flags;
  45 }
  46
  47 static inline void release_dma_lock(unsigned long flags)
  48 {
  49         spin_unlock_irqrestore(&dma_spin_lock, flags);
  50 }
  51
  52 /* Clear the 'DMA Pointer Flip Flop'.
  53  * Write 0 for LSB/MSB, 1 for MSB/LSB access.
  54  */
  55 #define clear_dma_ff(channel)
  56
  57 /* Set only the page register bits of the transfer address.
  58  *
  59  * NOTE: This is an architecture specific function, and should
  60  *       be hidden from the drivers
  61  */
  62 extern void set_dma_page(dmach_t channel, char pagenr);
  63
  64 /* Request a DMA channel
  65  *
  66  * Some architectures may need to do allocate an interrupt
  67  */
  68 extern int  request_dma(dmach_t channel, const char * device_id);
  69
  70 /* Free a DMA channel
  71  *
  72  * Some architectures may need to do free an interrupt
  73  */
  74 extern void free_dma(dmach_t channel);
  75
  76 /* Enable DMA for this channel
  77  *
  78  * On some architectures, this may have other side effects like
  79  * enabling an interrupt and setting the DMA registers.
  80  */
  81 extern void enable_dma(dmach_t channel);
  82
  83 /* Disable DMA for this channel
  84  *
  85  * On some architectures, this may have other side effects like
  86  * disabling an interrupt or whatever.
  87  */
  88 extern void disable_dma(dmach_t channel);
  89
  90 /* Test whether the specified channel has an active DMA transfer
  91  */
  92 extern int dma_channel_active(dmach_t channel);
  93
  94 /* Set the DMA scatter gather list for this channel
  95  *
  96  * This should not be called if a DMA channel is enabled,
  97  * especially since some DMA architectures don't update the
  98  * DMA address immediately, but defer it to the enable_dma().
  99  */
 100 extern void set_dma_sg(dmach_t channel, struct scatterlist *sg, int nr_sg);
 101
 102 /* Set the DMA address for this channel
 103  *
 104  * This should not be called if a DMA channel is enabled,
 105  * especially since some DMA architectures don't update the
 106  * DMA address immediately, but defer it to the enable_dma().
 107  */
 108 extern void __set_dma_addr(dmach_t channel, void *addr);
 109 #define set_dma_addr(channel, addr)                             \
 110         __set_dma_addr(channel, bus_to_virt(addr))
 111
 112 /* Set the DMA byte count for this channel
 113  *
 114  * This should not be called if a DMA channel is enabled,
 115  * especially since some DMA architectures don't update the
 116  * DMA count immediately, but defer it to the enable_dma().
 117  */
 118 extern void set_dma_count(dmach_t channel, unsigned long count);
 119
 120 /* Set the transfer direction for this channel
 121  *
 122  * This should not be called if a DMA channel is enabled,
 123  * especially since some DMA architectures don't update the
 124  * DMA transfer direction immediately, but defer it to the
 125  * enable_dma().
 126  */
 127 extern void set_dma_mode(dmach_t channel, dmamode_t mode);
 128
 129 /* Set the transfer speed for this channel
 130  */
 131 extern void set_dma_speed(dmach_t channel, int cycle_ns);
 132
 133 /* Get DMA residue count. After a DMA transfer, this
 134  * should return zero. Reading this while a DMA transfer is
 135  * still in progress will return unpredictable results.
 136  * If called before the channel has been used, it may return 1.
 137  * Otherwise, it returns the number of _bytes_ left to transfer.
 138  */
 139 extern int  get_dma_residue(dmach_t channel);
 140
 141 #ifndef NO_DMA
 142 #define NO_DMA  255
 143 #endif
 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 /* CONFIG_ISA_DMA_API */
 152
 153 #endif /* __ASM_ARM_DMA_H */