include/linux/dma-direct.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 /*
0003  * Internals of the DMA direct mapping implementation.  Only for use by the
0004  * DMA mapping code and IOMMU drivers.
0005  */
0006 #ifndef _LINUX_DMA_DIRECT_H
0007 #define _LINUX_DMA_DIRECT_H 1
0008
0009 #include <linux/dma-mapping.h>
0010 #include <linux/dma-map-ops.h>
0011 #include <linux/memblock.h> /* for min_low_pfn */
0012 #include <linux/mem_encrypt.h>
0013 #include <linux/swiotlb.h>
0014
0015 extern unsigned int zone_dma_bits;
0016
0017 /*
0018  * Record the mapping of CPU physical to DMA addresses for a given region.
0019  */
0020 struct bus_dma_region {
0021     phys_addr_t cpu_start;
0022     dma_addr_t  dma_start;
0023     u64     size;
0024     u64     offset;
0025 };
0026
0027 static inline dma_addr_t translate_phys_to_dma(struct device *dev,
0028         phys_addr_t paddr)
0029 {
0030     const struct bus_dma_region *m;
0031
0032     for (m = dev->dma_range_map; m->size; m++)
0033         if (paddr >= m->cpu_start && paddr - m->cpu_start < m->size)
0034             return (dma_addr_t)paddr - m->offset;
0035
0036     /* make sure dma_capable fails when no translation is available */
0037     return DMA_MAPPING_ERROR;
0038 }
0039
0040 static inline phys_addr_t translate_dma_to_phys(struct device *dev,
0041         dma_addr_t dma_addr)
0042 {
0043     const struct bus_dma_region *m;
0044
0045     for (m = dev->dma_range_map; m->size; m++)
0046         if (dma_addr >= m->dma_start && dma_addr - m->dma_start < m->size)
0047             return (phys_addr_t)dma_addr + m->offset;
0048
0049     return (phys_addr_t)-1;
0050 }
0051
0052 #ifdef CONFIG_ARCH_HAS_PHYS_TO_DMA
0053 #include <asm/dma-direct.h>
0054 #ifndef phys_to_dma_unencrypted
0055 #define phys_to_dma_unencrypted     phys_to_dma
0056 #endif
0057 #else
0058 static inline dma_addr_t phys_to_dma_unencrypted(struct device *dev,
0059         phys_addr_t paddr)
0060 {
0061     if (dev->dma_range_map)
0062         return translate_phys_to_dma(dev, paddr);
0063     return paddr;
0064 }
0065
0066 /*
0067  * If memory encryption is supported, phys_to_dma will set the memory encryption
0068  * bit in the DMA address, and dma_to_phys will clear it.
0069  * phys_to_dma_unencrypted is for use on special unencrypted memory like swiotlb
0070  * buffers.
0071  */
0072 static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
0073 {
0074     return __sme_set(phys_to_dma_unencrypted(dev, paddr));
0075 }
0076
0077 static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr)
0078 {
0079     phys_addr_t paddr;
0080
0081     if (dev->dma_range_map)
0082         paddr = translate_dma_to_phys(dev, dma_addr);
0083     else
0084         paddr = dma_addr;
0085
0086     return __sme_clr(paddr);
0087 }
0088 #endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */
0089
0090 #ifdef CONFIG_ARCH_HAS_FORCE_DMA_UNENCRYPTED
0091 bool force_dma_unencrypted(struct device *dev);
0092 #else
0093 static inline bool force_dma_unencrypted(struct device *dev)
0094 {
0095     return false;
0096 }
0097 #endif /* CONFIG_ARCH_HAS_FORCE_DMA_UNENCRYPTED */
0098
0099 static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size,
0100         bool is_ram)
0101 {
0102     dma_addr_t end = addr + size - 1;
0103
0104     if (addr == DMA_MAPPING_ERROR)
0105         return false;
0106     if (is_ram && !IS_ENABLED(CONFIG_ARCH_DMA_ADDR_T_64BIT) &&
0107         min(addr, end) < phys_to_dma(dev, PFN_PHYS(min_low_pfn)))
0108         return false;
0109
0110     return end <= min_not_zero(*dev->dma_mask, dev->bus_dma_limit);
0111 }
0112
0113 u64 dma_direct_get_required_mask(struct device *dev);
0114 void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
0115         gfp_t gfp, unsigned long attrs);
0116 void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,
0117         dma_addr_t dma_addr, unsigned long attrs);
0118 struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
0119         dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
0120 void dma_direct_free_pages(struct device *dev, size_t size,
0121         struct page *page, dma_addr_t dma_addr,
0122         enum dma_data_direction dir);
0123 int dma_direct_supported(struct device *dev, u64 mask);
0124 dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr,
0125         size_t size, enum dma_data_direction dir, unsigned long attrs);
0126
0127 #endif /* _LINUX_DMA_DIRECT_H */