xref: /openbmc/linux/arch/arm/include/asm/dma.h (revision 462cd772)
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 #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 #endif /* __ASM_ARM_DMA_H */
147