1 /*
2  * Copyright (c) 2015-2016 François Tigeot
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice unmodified, this list of conditions, and the following
10  *    disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 #ifndef _LINUX_DMA_MAPPING_H_
28 #define _LINUX_DMA_MAPPING_H_
29 
30 #include <linux/string.h>
31 #include <linux/device.h>
32 #include <linux/err.h>
33 #include <linux/dma-direction.h>
34 #include <linux/scatterlist.h>
35 
36 #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : (1ULL<<(n)) - 1)
37 
38 static inline dma_addr_t
39 dma_map_page(struct device *dev, struct vm_page *page,
40     unsigned long offset, size_t size, enum dma_data_direction direction)
41 {
42 	return VM_PAGE_TO_PHYS(page) + offset;
43 }
44 
45 static inline void dma_unmap_page(struct device *dev, dma_addr_t addr,
46 				  size_t size, enum dma_data_direction dir)
47 {
48 }
49 
50 static inline int
51 dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
52 {
53 	return 0;
54 }
55 
56 static inline int
57 dma_map_sg(struct device *dev, struct scatterlist *sg,
58 	   int nents, enum dma_data_direction dir)
59 {
60 	struct scatterlist *s;
61 	int i;
62 
63 	for_each_sg(sg, s, nents, i)
64 		s->dma_address = sg_phys(s);
65 
66 	return nents;
67 }
68 
69 static inline void
70 dma_unmap_sg(struct device *dev, struct scatterlist *sg,
71 	     int nents, enum dma_data_direction dir)
72 {
73 }
74 
75 static inline void *
76 dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle,
77     gfp_t flag)
78 {
79 	vm_paddr_t high;
80 	size_t align;
81 	void *mem;
82 
83 #if 0 /* XXX swildner */
84 	if (dev->dma_mask)
85 		high = *dev->dma_mask;
86 	else
87 #endif
88 		high = BUS_SPACE_MAXADDR_32BIT;
89 	align = PAGE_SIZE << get_order(size);
90 	mem = (void *)kmem_alloc_contig(size, 0, high, align);
91 	if (mem)
92 		*dma_handle = vtophys(mem);
93 	else
94 		*dma_handle = 0;
95 	return (mem);
96 }
97 
98 static inline void
99 dma_free_coherent(struct device *dev, size_t size, void *cpu_addr,
100     dma_addr_t dma_handle)
101 {
102 
103 	kmem_free(&kernel_map, (vm_offset_t)cpu_addr, size);
104 }
105 
106 #endif	/* _LINUX_DMA-MAPPING_H_ */
107