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 */