1  /* SPDX-License-Identifier: GPL-2.0-only */
 2  
 3  #ifndef REGION_FILE_H
 4  #define REGION_FILE_H
 5  
 6  #include <commonlib/region.h>
 7  #include <stddef.h>
 8  #include <stdint.h>
 9  
10  /*
11   * A region file is an abstraction to allow appending updates in a
12   * region_device where the data returned is the most recently written
13   * data. It is block based with a 16 byte granularity. So if you write
14   * 2 bytes into the file the data returned in the region_device would
15   * have 16 bytes allocated for the latest update. Additionally, the
16   * current maximum file size allowed is 1MiB - 48 bytes. See comments
17   * in C implementation file for further details.
18   */
19  
20  struct region_file;
21  
22  /*
23   * Initialize a region file associated with a provided region device.
24   * Returns < 0 on error, 0 on success.
25   */
26  int region_file_init(struct region_file *f, const struct region_device *p);
27  
28  /*
29   * Initialize region device object associated with latest update of file data.
30   * Returns < 0 on error, 0 on success.
31   */
32  int region_file_data(const struct region_file *f, struct region_device *rdev);
33  
34  /*
35   * Create region file entry struct to insert multiple data buffers
36   * into the same region_file.
37   */
38  struct update_region_file_entry {
39  	/* size of this entry */
40  	size_t size;
41  	/* data pointer */
42  	const void *data;
43  };
44  
45  /* Update region file with latest data. Returns < 0 on error, 0 on success. */
46  int region_file_update_data_arr(struct region_file *f,
47  				  const struct update_region_file_entry *entries,
48  				  size_t num_entries);
49  int region_file_update_data(struct region_file *f, const void *buf, size_t size);
50  
51  /* Declared here for easy object allocation. */
52  struct region_file {
53  	/* Region device covering file */
54  	struct region_device rdev;
55  	/* Metadata containing blocks of the data stream. */
56  	struct region_device metadata;
57  	/* Blocks forming data. */
58  	uint16_t data_blocks[2];
59  	/* Current slot in metadata marking end of data. */
60  	int slot;
61  };
62  
63  #endif /* REGION_FILE_H */