I'm surprised to see ION still is changing, after 4 years of in staging.
Here's the latest ION interface in ion.h, but Laura is mainly proposing to adjust ION API so that it relies on the kernel's DMA abstraction layer, the DMA mapping API, to handle DMA cache synchronization and MMU mapping, by updating mainly ion_map_dma_buf() in ion.c file, so that clients does not have to peek into ION objects to manage DMA operations.
It seems the new way would be to call dma_map_sg() directly using the ION object (or the dma_buf object associated with the ION object).
In comparison, the old way is shown in the call flow below.
1090 static struct dma_buf_ops dma_buf_ops = { 1091 .map_dma_buf = ion_map_dma_buf,
878 static struct sg_table *ion_map_dma_buf(struct dma_buf_attachment *attachment, 879 enum dma_data_direction direction)
75 /** 76 * ion_client_create() - allocate a client and returns it 77 * @dev: the global ion device 78 * @name: used for debugging 79 */ 80 struct ion_client *ion_client_create(struct ion_device *dev, 81 const char *name); 82 83 /** 84 * ion_client_destroy() - free's a client and all it's handles 85 * @client: the client 86 * 87 * Free the provided client and all it's resources including 88 * any handles it is holding. 89 */ 90 void ion_client_destroy(struct ion_client *client); 91 92 /** 93 * ion_alloc - allocate ion memory 94 * @client: the client 95 * @len: size of the allocation 96 * @align: requested allocation alignment, lots of hardware blocks 97 * have alignment requirements of some kind 98 * @heap_id_mask: mask of heaps to allocate from, if multiple bits are set 99 * heaps will be tried in order from highest to lowest 100 * id 101 * @flags: heap flags, the low 16 bits are consumed by ion, the 102 * high 16 bits are passed on to the respective heap and 103 * can be heap custom 104 * 105 * Allocate memory in one of the heaps provided in heap mask and return 106 * an opaque handle to it. 107 */ 108 struct ion_handle *ion_alloc(struct ion_client *client, size_t len, 109 size_t align, unsigned int heap_id_mask, 110 unsigned int flags); 111 112 /** 113 * ion_free - free a handle 114 * @client: the client 115 * @handle: the handle to free 116 * 117 * Free the provided handle. 118 */ 119 void ion_free(struct ion_client *client, struct ion_handle *handle); 120 121 /** 122 * ion_map_kernel - create mapping for the given handle 123 * @client: the client 124 * @handle: handle to map 125 * 126 * Map the given handle into the kernel and return a kernel address that 127 * can be used to access this address. 128 */ 129 void *ion_map_kernel(struct ion_client *client, struct ion_handle *handle); 130 131 /** 132 * ion_unmap_kernel() - destroy a kernel mapping for a handle 133 * @client: the client 134 * @handle: handle to unmap 135 */ 136 void ion_unmap_kernel(struct ion_client *client, struct ion_handle *handle); 137 138 /** 139 * ion_share_dma_buf() - share buffer as dma-buf 140 * @client: the client 141 * @handle: the handle 142 */ 143 struct dma_buf *ion_share_dma_buf(struct ion_client *client, 144 struct ion_handle *handle); 145 146 /** 147 * ion_share_dma_buf_fd() - given an ion client, create a dma-buf fd 148 * @client: the client 149 * @handle: the handle 150 */ 151 int ion_share_dma_buf_fd(struct ion_client *client, struct ion_handle *handle); 152 153 /** 154 * ion_import_dma_buf() - get ion_handle from dma-buf 155 * @client: the client 156 * @dmabuf: the dma-buf 157 * 158 * Get the ion_buffer associated with the dma-buf and return the ion_handle. 159 * If no ion_handle exists for this buffer, return newly created ion_handle. 160 * If dma-buf from another exporter is passed, return ERR_PTR(-EINVAL) 161 */ 162 struct ion_handle *ion_import_dma_buf(struct ion_client *client, 163 struct dma_buf *dmabuf); 164 165 /** 166 * ion_import_dma_buf_fd() - given a dma-buf fd from the ion exporter get handle 167 * @client: the client 168 * @fd: the dma-buf fd 169 * 170 * Given an dma-buf fd that was allocated through ion via ion_share_dma_buf_fd, 171 * import that fd and return a handle representing it. If a dma-buf from 172 * another exporter is passed in this function will return ERR_PTR(-EINVAL) 173 */ 174 struct ion_handle *ion_import_dma_buf_fd(struct ion_client *client, int fd); 175 176 #endif /* _LINUX_ION_H */
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