LXR linux/arch/arm/include/asm/dma-mapping.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef ASMARM_DMA_MAPPING_H
   3#define ASMARM_DMA_MAPPING_H
   4
   5#ifdef __KERNEL__
   6
   7#include <linux/mm_types.h>
   8#include <linux/scatterlist.h>
   9
  10#include <xen/xen.h>
  11#include <asm/xen/hypervisor.h>
  12
  13extern const struct dma_map_ops arm_dma_ops;
  14extern const struct dma_map_ops arm_coherent_dma_ops;
  15
  16static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
  17{
  18        if (IS_ENABLED(CONFIG_MMU) && !IS_ENABLED(CONFIG_ARM_LPAE))
  19                return &arm_dma_ops;
  20        return NULL;
  21}
  22
  23/**
  24 * arm_dma_alloc - allocate consistent memory for DMA
  25 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
  26 * @size: required memory size
  27 * @handle: bus-specific DMA address
  28 * @attrs: optinal attributes that specific mapping properties
  29 *
  30 * Allocate some memory for a device for performing DMA.  This function
  31 * allocates pages, and will return the CPU-viewed address, and sets @handle
  32 * to be the device-viewed address.
  33 */
  34extern void *arm_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
  35                           gfp_t gfp, unsigned long attrs);
  36
  37/**
  38 * arm_dma_free - free memory allocated by arm_dma_alloc
  39 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
  40 * @size: size of memory originally requested in dma_alloc_coherent
  41 * @cpu_addr: CPU-view address returned from dma_alloc_coherent
  42 * @handle: device-view address returned from dma_alloc_coherent
  43 * @attrs: optinal attributes that specific mapping properties
  44 *
  45 * Free (and unmap) a DMA buffer previously allocated by
  46 * arm_dma_alloc().
  47 *
  48 * References to memory and mappings associated with cpu_addr/handle
  49 * during and after this call executing are illegal.
  50 */
  51extern void arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
  52                         dma_addr_t handle, unsigned long attrs);
  53
  54/**
  55 * arm_dma_mmap - map a coherent DMA allocation into user space
  56 * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
  57 * @vma: vm_area_struct describing requested user mapping
  58 * @cpu_addr: kernel CPU-view address returned from dma_alloc_coherent
  59 * @handle: device-view address returned from dma_alloc_coherent
  60 * @size: size of memory originally requested in dma_alloc_coherent
  61 * @attrs: optinal attributes that specific mapping properties
  62 *
  63 * Map a coherent DMA buffer previously allocated by dma_alloc_coherent
  64 * into user space.  The coherent DMA buffer must not be freed by the
  65 * driver until the user space mapping has been released.
  66 */
  67extern int arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
  68                        void *cpu_addr, dma_addr_t dma_addr, size_t size,
  69                        unsigned long attrs);
  70
  71/*
  72 * For SA-1111, IXP425, and ADI systems  the dma-mapping functions are "magic"
  73 * and utilize bounce buffers as needed to work around limited DMA windows.
  74 *
  75 * On the SA-1111, a bug limits DMA to only certain regions of RAM.
  76 * On the IXP425, the PCI inbound window is 64MB (256MB total RAM)
  77 * On some ADI engineering systems, PCI inbound window is 32MB (12MB total RAM)
  78 *
  79 * The following are helper functions used by the dmabounce subystem
  80 *
  81 */
  82
  83/**
  84 * dmabounce_register_dev
  85 *
  86 * @dev: valid struct device pointer
  87 * @small_buf_size: size of buffers to use with small buffer pool
  88 * @large_buf_size: size of buffers to use with large buffer pool (can be 0)
  89 * @needs_bounce_fn: called to determine whether buffer needs bouncing
  90 *
  91 * This function should be called by low-level platform code to register
  92 * a device as requireing DMA buffer bouncing. The function will allocate
  93 * appropriate DMA pools for the device.
  94 */
  95extern int dmabounce_register_dev(struct device *, unsigned long,
  96                unsigned long, int (*)(struct device *, dma_addr_t, size_t));
  97
  98/**
  99 * dmabounce_unregister_dev
 100 *
 101 * @dev: valid struct device pointer
 102 *
 103 * This function should be called by low-level platform code when device
 104 * that was previously registered with dmabounce_register_dev is removed
 105 * from the system.
 106 *
 107 */
 108extern void dmabounce_unregister_dev(struct device *);
 109
 110
 111
 112/*
 113 * The scatter list versions of the above methods.
 114 */
 115extern int arm_dma_map_sg(struct device *, struct scatterlist *, int,
 116                enum dma_data_direction, unsigned long attrs);
 117extern void arm_dma_unmap_sg(struct device *, struct scatterlist *, int,
 118                enum dma_data_direction, unsigned long attrs);
 119extern void arm_dma_sync_sg_for_cpu(struct device *, struct scatterlist *, int,
 120                enum dma_data_direction);
 121extern void arm_dma_sync_sg_for_device(struct device *, struct scatterlist *, int,
 122                enum dma_data_direction);
 123extern int arm_dma_get_sgtable(struct device *dev, struct sg_table *sgt,
 124                void *cpu_addr, dma_addr_t dma_addr, size_t size,
 125                unsigned long attrs);
 126
 127#endif /* __KERNEL__ */
 128#endif
 129