1SPDX-License-Identifier: GPL-2.0+ 2/* 3 * Copyright 2014 Broadcom Corporation. 4 */ 5 6Semihosting is ARM's way of having a real or virtual target communicate 7with a host or host debugger for basic operations such as file I/O, 8console I/O, etc. Please see 9http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0471c/Bgbjjgij.html for more information. 10 11For developing on armv8 virtual fastmodel platforms, semihosting is a 12valuable tool since it allows access to image/configuration files before 13eMMC or other NV media are available. 14 15There are two main ARM virtual Fixed Virtual Platform (FVP) models, 16Versatile Express (VE) FVP and BASE FVP (See 17http://www.arm.com/products/tools/models/fast-models/foundation-model.php) 18The initial vexpress64 u-boot board created here runs on the VE virtual 19platform using the license-free Foundation_v8 simulator. Fortunately, 20the Foundation_v8 simulator also supports the BASE_FVP model which 21companies can purchase licenses for and contain much more functionality. 22So we can, in u-boot, run either model by either using the VE FVP (default), 23or turning on CONFIG_BASE_FVP for the more full featured model. 24 25Rather than create a new armv8 board similar to armltd/vexpress64, add 26semihosting calls to the existing one, enabled with CONFIG_SEMIHOSTING 27and CONFIG_BASE_FVP both set. Also reuse the existing board config file 28vexpress_aemv8a.h but differentiate the two models by the presence or 29absence of CONFIG_BASE_FVP. This change is tested and works on both the 30Foundation and Base fastmodel simulators. 31 32The semihosting code adds a command: 33 34 smhload <image> <address> [env var] 35 36That will load an image from the host filesystem into RAM at the specified 37address and optionally store the load end address in the specified 38environment variable. 39