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
claim_dma_lock(void)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
release_dma_lock(unsigned long flags)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