Merge 4.16

Change-Id: I11db70a8e25a6656c5ec640a703e7b06d5a3672e

payloads/libpayload/include/boot_device.h

@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+
+#ifndef _BOOT_DEVICE_H
+#define _BOOT_DEVICE_H
+
+#include <stddef.h>
+
+/**
+ * This is a boot device access function, which is used by libpayload to read data from
+ * the flash memory (or other boot device). It has to be implemented by payloads that want
+ * to use FMAP or libcbfs.
+ *
+ * @param buf The output buffer to which the data should be written to.
+ * @param offset Absolute offset in bytes of the requested boot device memory area. Not aligned.
+ * @param size Size in bytes of the requested boot device memory area. Not aligned.
+ *
+ * @returns Number of bytes returned to the buffer, or negative value on error. Typically should
+ *          be equal to the `size`, and not aligned forcefully.
+ */
+ssize_t boot_device_read(void *buf, size_t offset, size_t size);
+
+#endif /* _BOOT_DEVICE_H */