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 */ 153