src/include/region_file.h

   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 */