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