1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Internals of the DMA direct mapping implementation. Only for use by the
4 * DMA mapping code and IOMMU drivers.
5 */
6#ifndef _LINUX_DMA_DIRECT_H
7#define _LINUX_DMA_DIRECT_H 1
8
9#include <linux/dma-mapping.h>
10#include <linux/dma-map-ops.h>
11#include <linux/memblock.h> /* for min_low_pfn */
12#include <linux/mem_encrypt.h>
13#include <linux/swiotlb.h>
14
15extern u64 zone_dma_limit;
16
17/*
18 * Record the mapping of CPU physical to DMA addresses for a given region.
19 */
20struct bus_dma_region {
21 phys_addr_t cpu_start;
22 dma_addr_t dma_start;
23 u64 size;
24};
25
26static inline dma_addr_t translate_phys_to_dma(struct device *dev,
27 phys_addr_t paddr)
28{
29 const struct bus_dma_region *m;
30
31 for (m = dev->dma_range_map; m->size; m++) {
32 u64 offset = paddr - m->cpu_start;
33
34 if (paddr >= m->cpu_start && offset < m->size)
35 return m->dma_start + offset;
36 }
37
38 /* make sure dma_capable fails when no translation is available */
39 return DMA_MAPPING_ERROR;
40}
41
42static inline phys_addr_t translate_dma_to_phys(struct device *dev,
43 dma_addr_t dma_addr)
44{
45 const struct bus_dma_region *m;
46
47 for (m = dev->dma_range_map; m->size; m++) {
48 u64 offset = dma_addr - m->dma_start;
49
50 if (dma_addr >= m->dma_start && offset < m->size)
51 return m->cpu_start + offset;
52 }
53
54 return (phys_addr_t)-1;
55}
56
57static inline dma_addr_t dma_range_map_min(const struct bus_dma_region *map)
58{
59 dma_addr_t ret = (dma_addr_t)U64_MAX;
60
61 for (; map->size; map++)
62 ret = min(ret, map->dma_start);
63 return ret;
64}
65
66static inline dma_addr_t dma_range_map_max(const struct bus_dma_region *map)
67{
68 dma_addr_t ret = 0;
69
70 for (; map->size; map++)
71 ret = max(ret, map->dma_start + map->size - 1);
72 return ret;
73}
74
75#ifdef CONFIG_ARCH_HAS_PHYS_TO_DMA
76#include <asm/dma-direct.h>
77#ifndef phys_to_dma_unencrypted
78#define phys_to_dma_unencrypted phys_to_dma
79#endif
80#else
81static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
82{
83 if (dev->dma_range_map)
84 return translate_phys_to_dma(dev, paddr);
85 return paddr;
86}
87
88static inline dma_addr_t phys_to_dma_unencrypted(struct device *dev,
89 phys_addr_t paddr)
90{
91 return dma_addr_unencrypted(__phys_to_dma(dev, paddr));
92}
93/*
94 * If memory encryption is supported, phys_to_dma will set the memory encryption
95 * bit in the DMA address, and dma_to_phys will clear it.
96 * phys_to_dma_unencrypted is for use on special unencrypted memory like swiotlb
97 * buffers.
98 */
99static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
100{
101 return dma_addr_encrypted(__phys_to_dma(dev, paddr));
102}
103
104static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr)
105{
106 phys_addr_t paddr;
107
108 dma_addr = dma_addr_canonical(dma_addr);
109 if (dev->dma_range_map)
110 paddr = translate_dma_to_phys(dev, dma_addr);
111 else
112 paddr = dma_addr;
113
114 return paddr;
115}
116#endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */
117
118#ifdef CONFIG_ARCH_HAS_FORCE_DMA_UNENCRYPTED
119bool force_dma_unencrypted(struct device *dev);
120#else
121static inline bool force_dma_unencrypted(struct device *dev)
122{
123 return false;
124}
125#endif /* CONFIG_ARCH_HAS_FORCE_DMA_UNENCRYPTED */
126
127static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size,
128 bool is_ram)
129{
130 dma_addr_t end = addr + size - 1;
131
132 if (addr == DMA_MAPPING_ERROR)
133 return false;
134 if (is_ram && !IS_ENABLED(CONFIG_ARCH_DMA_ADDR_T_64BIT) &&
135 min(addr, end) < phys_to_dma(dev, PFN_PHYS(min_low_pfn)))
136 return false;
137
138 return end <= min_not_zero(*dev->dma_mask, dev->bus_dma_limit);
139}
140
141u64 dma_direct_get_required_mask(struct device *dev);
142void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
143 gfp_t gfp, unsigned long attrs);
144void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,
145 dma_addr_t dma_addr, unsigned long attrs);
146struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
147 dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
148void dma_direct_free_pages(struct device *dev, size_t size,
149 struct page *page, dma_addr_t dma_addr,
150 enum dma_data_direction dir);
151int dma_direct_supported(struct device *dev, u64 mask);
152
153#endif /* _LINUX_DMA_DIRECT_H */
154

source code of linux/include/linux/dma-direct.h