xref: /openbmc/linux/include/linux/dma-direct.h (revision 9f4df96b)
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 
15 extern unsigned int zone_dma_bits;
16 
17 /*
18  * Record the mapping of CPU physical to DMA addresses for a given region.
19  */
20 struct bus_dma_region {
21 	phys_addr_t	cpu_start;
22 	dma_addr_t	dma_start;
23 	u64		size;
24 	u64		offset;
25 };
26 
translate_phys_to_dma(struct device * dev,phys_addr_t paddr)27 static inline dma_addr_t translate_phys_to_dma(struct device *dev,
28 		phys_addr_t paddr)
29 {
30 	const struct bus_dma_region *m;
31 
32 	for (m = dev->dma_range_map; m->size; m++)
33 		if (paddr >= m->cpu_start && paddr - m->cpu_start < m->size)
34 			return (dma_addr_t)paddr - m->offset;
35 
36 	/* make sure dma_capable fails when no translation is available */
37 	return DMA_MAPPING_ERROR;
38 }
39 
translate_dma_to_phys(struct device * dev,dma_addr_t dma_addr)40 static inline phys_addr_t translate_dma_to_phys(struct device *dev,
41 		dma_addr_t dma_addr)
42 {
43 	const struct bus_dma_region *m;
44 
45 	for (m = dev->dma_range_map; m->size; m++)
46 		if (dma_addr >= m->dma_start && dma_addr - m->dma_start < m->size)
47 			return (phys_addr_t)dma_addr + m->offset;
48 
49 	return (phys_addr_t)-1;
50 }
51 
52 #ifdef CONFIG_ARCH_HAS_PHYS_TO_DMA
53 #include <asm/dma-direct.h>
54 #ifndef phys_to_dma_unencrypted
55 #define phys_to_dma_unencrypted		phys_to_dma
56 #endif
57 #else
phys_to_dma_unencrypted(struct device * dev,phys_addr_t paddr)58 static inline dma_addr_t phys_to_dma_unencrypted(struct device *dev,
59 		phys_addr_t paddr)
60 {
61 	if (dev->dma_range_map)
62 		return translate_phys_to_dma(dev, paddr);
63 	return paddr;
64 }
65 
66 /*
67  * If memory encryption is supported, phys_to_dma will set the memory encryption
68  * bit in the DMA address, and dma_to_phys will clear it.
69  * phys_to_dma_unencrypted is for use on special unencrypted memory like swiotlb
70  * buffers.
71  */
phys_to_dma(struct device * dev,phys_addr_t paddr)72 static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
73 {
74 	return __sme_set(phys_to_dma_unencrypted(dev, paddr));
75 }
76 
dma_to_phys(struct device * dev,dma_addr_t dma_addr)77 static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr)
78 {
79 	phys_addr_t paddr;
80 
81 	if (dev->dma_range_map)
82 		paddr = translate_dma_to_phys(dev, dma_addr);
83 	else
84 		paddr = dma_addr;
85 
86 	return __sme_clr(paddr);
87 }
88 #endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */
89 
90 #ifdef CONFIG_ARCH_HAS_FORCE_DMA_UNENCRYPTED
91 bool force_dma_unencrypted(struct device *dev);
92 #else
force_dma_unencrypted(struct device * dev)93 static inline bool force_dma_unencrypted(struct device *dev)
94 {
95 	return false;
96 }
97 #endif /* CONFIG_ARCH_HAS_FORCE_DMA_UNENCRYPTED */
98 
dma_capable(struct device * dev,dma_addr_t addr,size_t size,bool is_ram)99 static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size,
100 		bool is_ram)
101 {
102 	dma_addr_t end = addr + size - 1;
103 
104 	if (addr == DMA_MAPPING_ERROR)
105 		return false;
106 	if (is_ram && !IS_ENABLED(CONFIG_ARCH_DMA_ADDR_T_64BIT) &&
107 	    min(addr, end) < phys_to_dma(dev, PFN_PHYS(min_low_pfn)))
108 		return false;
109 
110 	return end <= min_not_zero(*dev->dma_mask, dev->bus_dma_limit);
111 }
112 
113 u64 dma_direct_get_required_mask(struct device *dev);
114 void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
115 		gfp_t gfp, unsigned long attrs);
116 void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,
117 		dma_addr_t dma_addr, unsigned long attrs);
118 struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
119 		dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
120 void dma_direct_free_pages(struct device *dev, size_t size,
121 		struct page *page, dma_addr_t dma_addr,
122 		enum dma_data_direction dir);
123 int dma_direct_supported(struct device *dev, u64 mask);
124 dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr,
125 		size_t size, enum dma_data_direction dir, unsigned long attrs);
126 
127 #endif /* _LINUX_DMA_DIRECT_H */
128