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 < (0x100000000ULL - PAGE_OFFSET) ? \ 14 (PAGE_OFFSET + arm_dma_zone_size) : 0xffffffffUL; }) 15 16 extern phys_addr_t arm_dma_limit; 17 #define ARCH_LOW_ADDRESS_LIMIT arm_dma_limit 18 #endif 19 20 #ifdef CONFIG_ISA_DMA_API 21 /* 22 * This is used to support drivers written for the x86 ISA DMA API. 23 * It should not be re-used except for that purpose. 24 */ 25 #include <linux/spinlock.h> 26 #include <linux/scatterlist.h> 27 28 #include <mach/isa-dma.h> 29 30 /* 31 * The DMA modes reflect the settings for the ISA DMA controller 32 */ 33 #define DMA_MODE_MASK 0xcc 34 35 #define DMA_MODE_READ 0x44 36 #define DMA_MODE_WRITE 0x48 37 #define DMA_MODE_CASCADE 0xc0 38 #define DMA_AUTOINIT 0x10 39 40 extern raw_spinlock_t dma_spin_lock; 41 42 static inline unsigned long claim_dma_lock(void) 43 { 44 unsigned long flags; 45 raw_spin_lock_irqsave(&dma_spin_lock, flags); 46 return flags; 47 } 48 49 static inline void release_dma_lock(unsigned long flags) 50 { 51 raw_spin_unlock_irqrestore(&dma_spin_lock, flags); 52 } 53 54 /* Clear the 'DMA Pointer Flip Flop'. 55 * Write 0 for LSB/MSB, 1 for MSB/LSB access. 56 */ 57 #define clear_dma_ff(chan) 58 59 /* Set only the page register bits of the transfer address. 60 * 61 * NOTE: This is an architecture specific function, and should 62 * be hidden from the drivers 63 */ 64 extern void set_dma_page(unsigned int chan, char pagenr); 65 66 /* Request a DMA channel 67 * 68 * Some architectures may need to do allocate an interrupt 69 */ 70 extern int request_dma(unsigned int chan, const char * device_id); 71 72 /* Free a DMA channel 73 * 74 * Some architectures may need to do free an interrupt 75 */ 76 extern void free_dma(unsigned int chan); 77 78 /* Enable DMA for this channel 79 * 80 * On some architectures, this may have other side effects like 81 * enabling an interrupt and setting the DMA registers. 82 */ 83 extern void enable_dma(unsigned int chan); 84 85 /* Disable DMA for this channel 86 * 87 * On some architectures, this may have other side effects like 88 * disabling an interrupt or whatever. 89 */ 90 extern void disable_dma(unsigned int chan); 91 92 /* Test whether the specified channel has an active DMA transfer 93 */ 94 extern int dma_channel_active(unsigned int chan); 95 96 /* Set the DMA scatter gather list for this channel 97 * 98 * This should not be called if a DMA channel is enabled, 99 * especially since some DMA architectures don't update the 100 * DMA address immediately, but defer it to the enable_dma(). 101 */ 102 extern void set_dma_sg(unsigned int chan, struct scatterlist *sg, int nr_sg); 103 104 /* Set the DMA address for this channel 105 * 106 * This should not be called if a DMA channel is enabled, 107 * especially since some DMA architectures don't update the 108 * DMA address immediately, but defer it to the enable_dma(). 109 */ 110 extern void __set_dma_addr(unsigned int chan, void *addr); 111 #define set_dma_addr(chan, addr) \ 112 __set_dma_addr(chan, (void *)isa_bus_to_virt(addr)) 113 114 /* Set the DMA byte count for this channel 115 * 116 * This should not be called if a DMA channel is enabled, 117 * especially since some DMA architectures don't update the 118 * DMA count immediately, but defer it to the enable_dma(). 119 */ 120 extern void set_dma_count(unsigned int chan, unsigned long count); 121 122 /* Set the transfer direction for this channel 123 * 124 * This should not be called if a DMA channel is enabled, 125 * especially since some DMA architectures don't update the 126 * DMA transfer direction immediately, but defer it to the 127 * enable_dma(). 128 */ 129 extern void set_dma_mode(unsigned int chan, unsigned int mode); 130 131 /* Set the transfer speed for this channel 132 */ 133 extern void set_dma_speed(unsigned int chan, int cycle_ns); 134 135 /* Get DMA residue count. After a DMA transfer, this 136 * should return zero. Reading this while a DMA transfer is 137 * still in progress will return unpredictable results. 138 * If called before the channel has been used, it may return 1. 139 * Otherwise, it returns the number of _bytes_ left to transfer. 140 */ 141 extern int get_dma_residue(unsigned int chan); 142 143 #ifndef NO_DMA 144 #define NO_DMA 255 145 #endif 146 147 #endif /* CONFIG_ISA_DMA_API */ 148 149 #endif /* __ASM_ARM_DMA_H */ 150