NAME
	/harness/flash.bin

DESCRIPTION
	Access to the flash storage chip (where the harness firmware
	is stored).

	Any number of readers may read the flash contents.

	Only one writer can have the file open at a time; once the
	file is closed, the harness reboots into the new firmware.
	Writes to the top half of the chip will fail.

BUGS
	- The size of the chip is configured at compile-time.  If the
	  firmware is loaded onto hardware with a larger flash chip
	  than it was compiled for, then the upper part of the chip
	  will not be accessible with this file.  If the firmware is
	  loaded onto hardware with a smaller flash chip than it was
	  compiled for, then accessing the missing upper part of the
	  chip will crash.

	- When writing to the flash using this file, only half of the
	  chip capacity is usable; the top half and bottom half are
	  mirrors of each-other.  This is to avoid the firmware
	  crashing as its program text is overwritten; the firmware is
	  executing out of the bottom half, and writing to the top
	  half; once the file is closed, a minimal in-RAM function
	  copies the top half to the bottom half and reboots.

AUTHOR
	Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
	SPDX-License-Identifier: AGPL-3.0-or-later