Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
dma.h
Go to the documentation of this file.
1 #ifndef __ASM_ARM_DMA_H
2 #define __ASM_ARM_DMA_H
3 
4 /*
5  * This is the maximum virtual address which can be DMA'd from.
6  */
7 #ifndef CONFIG_ZONE_DMA
8 #define MAX_DMA_ADDRESS 0xffffffffUL
9 #else
10 #define MAX_DMA_ADDRESS ({ \
11  extern unsigned long arm_dma_zone_size; \
12  arm_dma_zone_size ? \
13  (PAGE_OFFSET + arm_dma_zone_size) : 0xffffffffUL; })
14 #endif
15 
16 #ifdef CONFIG_ISA_DMA_API
17 /*
18  * This is used to support drivers written for the x86 ISA DMA API.
19  * It should not be re-used except for that purpose.
20  */
21 #include <linux/spinlock.h>
22 #include <asm/scatterlist.h>
23 
24 #include <mach/isa-dma.h>
25 
26 /*
27  * The DMA modes reflect the settings for the ISA DMA controller
28  */
29 #define DMA_MODE_MASK 0xcc
30 
31 #define DMA_MODE_READ 0x44
32 #define DMA_MODE_WRITE 0x48
33 #define DMA_MODE_CASCADE 0xc0
34 #define DMA_AUTOINIT 0x10
35 
37 
38 static inline unsigned long claim_dma_lock(void)
39 {
40  unsigned long flags;
41  raw_spin_lock_irqsave(&dma_spin_lock, flags);
42  return flags;
43 }
44 
45 static inline void release_dma_lock(unsigned long flags)
46 {
47  raw_spin_unlock_irqrestore(&dma_spin_lock, flags);
48 }
49 
50 /* Clear the 'DMA Pointer Flip Flop'.
51  * Write 0 for LSB/MSB, 1 for MSB/LSB access.
52  */
53 #define clear_dma_ff(chan)
54 
55 /* Set only the page register bits of the transfer address.
56  *
57  * NOTE: This is an architecture specific function, and should
58  * be hidden from the drivers
59  */
60 extern void set_dma_page(unsigned int chan, char pagenr);
61 
62 /* Request a DMA channel
63  *
64  * Some architectures may need to do allocate an interrupt
65  */
66 extern int request_dma(unsigned int chan, const char * device_id);
67 
68 /* Free a DMA channel
69  *
70  * Some architectures may need to do free an interrupt
71  */
72 extern void free_dma(unsigned int chan);
73 
74 /* Enable DMA for this channel
75  *
76  * On some architectures, this may have other side effects like
77  * enabling an interrupt and setting the DMA registers.
78  */
79 extern void enable_dma(unsigned int chan);
80 
81 /* Disable DMA for this channel
82  *
83  * On some architectures, this may have other side effects like
84  * disabling an interrupt or whatever.
85  */
86 extern void disable_dma(unsigned int chan);
87 
88 /* Test whether the specified channel has an active DMA transfer
89  */
90 extern int dma_channel_active(unsigned int chan);
91 
92 /* Set the DMA scatter gather list for this channel
93  *
94  * This should not be called if a DMA channel is enabled,
95  * especially since some DMA architectures don't update the
96  * DMA address immediately, but defer it to the enable_dma().
97  */
98 extern void set_dma_sg(unsigned int chan, struct scatterlist *sg, int nr_sg);
99 
100 /* Set the DMA address for this channel
101  *
102  * This should not be called if a DMA channel is enabled,
103  * especially since some DMA architectures don't update the
104  * DMA address immediately, but defer it to the enable_dma().
105  */
106 extern void __set_dma_addr(unsigned int chan, void *addr);
107 #define set_dma_addr(chan, addr) \
108  __set_dma_addr(chan, bus_to_virt(addr))
109 
110 /* Set the DMA byte count for this channel
111  *
112  * This should not be called if a DMA channel is enabled,
113  * especially since some DMA architectures don't update the
114  * DMA count immediately, but defer it to the enable_dma().
115  */
116 extern void set_dma_count(unsigned int chan, unsigned long count);
117 
118 /* Set the transfer direction for this channel
119  *
120  * This should not be called if a DMA channel is enabled,
121  * especially since some DMA architectures don't update the
122  * DMA transfer direction immediately, but defer it to the
123  * enable_dma().
124  */
125 extern void set_dma_mode(unsigned int chan, unsigned int mode);
126 
127 /* Set the transfer speed for this channel
128  */
129 extern void set_dma_speed(unsigned int chan, int cycle_ns);
130 
131 /* Get DMA residue count. After a DMA transfer, this
132  * should return zero. Reading this while a DMA transfer is
133  * still in progress will return unpredictable results.
134  * If called before the channel has been used, it may return 1.
135  * Otherwise, it returns the number of _bytes_ left to transfer.
136  */
137 extern int get_dma_residue(unsigned int chan);
138 
139 #ifndef NO_DMA
140 #define NO_DMA 255
141 #endif
142 
143 #endif /* CONFIG_ISA_DMA_API */
144 
145 #ifdef CONFIG_PCI
146 extern int isa_dma_bridge_buggy;
147 #else
148 #define isa_dma_bridge_buggy (0)
149 #endif
150 
151 #endif /* __ASM_ARM_DMA_H */