payloads/libpayload/include/boot_device.h

   1 /* SPDX-License-Identifier: BSD-3-Clause */
   2
   3 #ifndef _BOOT_DEVICE_H
   4 #define _BOOT_DEVICE_H
   5
   6 #include <stddef.h>
   7
   8 /**
   9  * This is a boot device access function, which is used by libpayload to read data from
  10  * the flash memory (or other boot device). It has to be implemented by payloads that want
  11  * to use FMAP or libcbfs.
  12  *
  13  * @param buf The output buffer to which the data should be written to.
  14  * @param offset Absolute offset in bytes of the requested boot device memory area. Not aligned.
  15  * @param size Size in bytes of the requested boot device memory area. Not aligned.
  16  *
  17  * @returns Number of bytes returned to the buffer, or negative value on error. Typically should
  18  *          be equal to the `size`, and not aligned forcefully.
  19  */
  20 ssize_t boot_device_read(void *buf, size_t offset, size_t size);
  21
  22 #endif /* _BOOT_DEVICE_H */