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https://github.com/AsahiLinux/u-boot
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83d290c56f
When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
38 lines
1.7 KiB
Text
38 lines
1.7 KiB
Text
SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright 2014 Broadcom Corporation.
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*/
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Semihosting is ARM's way of having a real or virtual target communicate
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with a host or host debugger for basic operations such as file I/O,
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console I/O, etc. Please see
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http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0471c/Bgbjjgij.html for more information.
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For developing on armv8 virtual fastmodel platforms, semihosting is a
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valuable tool since it allows access to image/configuration files before
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eMMC or other NV media are available.
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There are two main ARM virtual Fixed Virtual Platform (FVP) models,
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Versatile Express (VE) FVP and BASE FVP (See
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http://www.arm.com/products/tools/models/fast-models/foundation-model.php)
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The initial vexpress64 u-boot board created here runs on the VE virtual
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platform using the license-free Foundation_v8 simulator. Fortunately,
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the Foundation_v8 simulator also supports the BASE_FVP model which
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companies can purchase licenses for and contain much more functionality.
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So we can, in u-boot, run either model by either using the VE FVP (default),
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or turning on CONFIG_BASE_FVP for the more full featured model.
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Rather than create a new armv8 board similar to armltd/vexpress64, add
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semihosting calls to the existing one, enabled with CONFIG_SEMIHOSTING
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and CONFIG_BASE_FVP both set. Also reuse the existing board config file
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vexpress_aemv8a.h but differentiate the two models by the presence or
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absence of CONFIG_BASE_FVP. This change is tested and works on both the
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Foundation and Base fastmodel simulators.
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The semihosting code adds a command:
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smhload <image> <address> [env var]
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That will load an image from the host filesystem into RAM at the specified
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address and optionally store the load end address in the specified
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environment variable.
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