arch/arm/include/asm/dma.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ASM_ARM_DMA_H
   3 #define __ASM_ARM_DMA_H
   4
   5 /*
   6  * This is the maximum virtual address which can be DMA'd from.
   7  */
   8 #ifndef CONFIG_ZONE_DMA
   9 #define MAX_DMA_ADDRESS 0xffffffffUL
  10 #else
  11 #define MAX_DMA_ADDRESS ({ \
  12         extern phys_addr_t arm_dma_zone_size; \
  13         arm_dma_zone_size && arm_dma_zone_size < (0x10000000 - PAGE_OFFSET) ? \
  14                 (PAGE_OFFSET + arm_dma_zone_size) : 0xffffffffUL; })
  15 #endif
  16
  17 #ifdef CONFIG_ISA_DMA_API
  18 /*
  19  * This is used to support drivers written for the x86 ISA DMA API.
  20  * It should not be re-used except for that purpose.
  21  */
  22 #include <linux/spinlock.h>
  23 #include <linux/scatterlist.h>
  24
  25 #include <mach/isa-dma.h>
  26
  27 /*
  28  * The DMA modes reflect the settings for the ISA DMA controller
  29  */
  30 #define DMA_MODE_MASK    0xcc
  31
  32 #define DMA_MODE_READ    0x44
  33 #define DMA_MODE_WRITE   0x48
  34 #define DMA_MODE_CASCADE 0xc0
  35 #define DMA_AUTOINIT     0x10
  36
  37 extern raw_spinlock_t  dma_spin_lock;
  38
  39 static inline unsigned long claim_dma_lock(void)
  40 {
  41         unsigned long flags;
  42         raw_spin_lock_irqsave(&dma_spin_lock, flags);
  43         return flags;
  44 }
  45
  46 static inline void release_dma_lock(unsigned long flags)
  47 {
  48         raw_spin_unlock_irqrestore(&dma_spin_lock, flags);
  49 }
  50
  51 /* Clear the 'DMA Pointer Flip Flop'.
  52  * Write 0 for LSB/MSB, 1 for MSB/LSB access.
  53  */
  54 #define clear_dma_ff(chan)
  55
  56 /* Set only the page register bits of the transfer address.
  57  *
  58  * NOTE: This is an architecture specific function, and should
  59  *       be hidden from the drivers
  60  */
  61 extern void set_dma_page(unsigned int chan, char pagenr);
  62
  63 /* Request a DMA channel
  64  *
  65  * Some architectures may need to do allocate an interrupt
  66  */
  67 extern int  request_dma(unsigned int chan, const char * device_id);
  68
  69 /* Free a DMA channel
  70  *
  71  * Some architectures may need to do free an interrupt
  72  */
  73 extern void free_dma(unsigned int chan);
  74
  75 /* Enable DMA for this channel
  76  *
  77  * On some architectures, this may have other side effects like
  78  * enabling an interrupt and setting the DMA registers.
  79  */
  80 extern void enable_dma(unsigned int chan);
  81
  82 /* Disable DMA for this channel
  83  *
  84  * On some architectures, this may have other side effects like
  85  * disabling an interrupt or whatever.
  86  */
  87 extern void disable_dma(unsigned int chan);
  88
  89 /* Test whether the specified channel has an active DMA transfer
  90  */
  91 extern int dma_channel_active(unsigned int chan);
  92
  93 /* Set the DMA scatter gather list for this channel
  94  *
  95  * This should not be called if a DMA channel is enabled,
  96  * especially since some DMA architectures don't update the
  97  * DMA address immediately, but defer it to the enable_dma().
  98  */
  99 extern void set_dma_sg(unsigned int chan, struct scatterlist *sg, int nr_sg);
 100
 101 /* Set the DMA address for this channel
 102  *
 103  * This should not be called if a DMA channel is enabled,
 104  * especially since some DMA architectures don't update the
 105  * DMA address immediately, but defer it to the enable_dma().
 106  */
 107 extern void __set_dma_addr(unsigned int chan, void *addr);
 108 #define set_dma_addr(chan, addr)                                \
 109         __set_dma_addr(chan, (void *)__bus_to_virt(addr))
 110
 111 /* Set the DMA byte count for this channel
 112  *
 113  * This should not be called if a DMA channel is enabled,
 114  * especially since some DMA architectures don't update the
 115  * DMA count immediately, but defer it to the enable_dma().
 116  */
 117 extern void set_dma_count(unsigned int chan, unsigned long count);
 118
 119 /* Set the transfer direction for this channel
 120  *
 121  * This should not be called if a DMA channel is enabled,
 122  * especially since some DMA architectures don't update the
 123  * DMA transfer direction immediately, but defer it to the
 124  * enable_dma().
 125  */
 126 extern void set_dma_mode(unsigned int chan, unsigned int mode);
 127
 128 /* Set the transfer speed for this channel
 129  */
 130 extern void set_dma_speed(unsigned int chan, int cycle_ns);
 131
 132 /* Get DMA residue count. After a DMA transfer, this
 133  * should return zero. Reading this while a DMA transfer is
 134  * still in progress will return unpredictable results.
 135  * If called before the channel has been used, it may return 1.
 136  * Otherwise, it returns the number of _bytes_ left to transfer.
 137  */
 138 extern int  get_dma_residue(unsigned int chan);
 139
 140 #ifndef NO_DMA
 141 #define NO_DMA  255
 142 #endif
 143
 144 #endif /* CONFIG_ISA_DMA_API */
 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 /* __ASM_ARM_DMA_H */