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476476e73b
It is useful to be able to load U-Boot onto a board even if is it already running EFI. This can allow access to the U-Boot command interface, flexible booting options and easier development. The easiest way to do this is to build U-Boot as a binary blob and have an EFI stub copy it into RAM. Add support for this feature, targeting 32-bit initially. Also add a way to detect when U-Boot has been loaded via a stub. This goes in common.h since it needs to be widely available so that we avoid redoing initialisation that should be skipped. Signed-off-by: Simon Glass <sjg@chromium.org> Improvements to how the payload is built: Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Tested-by: Bin Meng <bmeng.cn@gmail.com>
55 lines
1.7 KiB
Plaintext
55 lines
1.7 KiB
Plaintext
config EFI
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bool "Support running U-Boot from EFI"
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depends on X86
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help
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U-Boot can be started from EFI on certain platforms. This allows
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EFI to perform most of the system init and then jump to U-Boot for
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final system boot. Another option is to run U-Boot as an EFI
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application, with U-Boot using EFI's drivers instead of its own.
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choice
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prompt "Select EFI mode to use"
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depends on X86 && EFI
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config EFI_APP
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bool "Support running as an EFI application"
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help
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Build U-Boot as an application which can be started from EFI. This
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is useful for examining a platform in the early stages of porting
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U-Boot to it. It allows only very basic functionality, such as a
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command prompt and memory and I/O functions. Use 'reset' to return
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to EFI.
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config EFI_STUB
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bool "Support running as an EFI payload"
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endchoice
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config EFI_RAM_SIZE
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hex "Amount of EFI RAM for U-Boot"
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depends on EFI_APP
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default 0x2000000
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help
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Set the amount of EFI RAM which is claimed by U-Boot for its own
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use. U-Boot allocates this from EFI on start-up (along with a few
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other smaller amounts) and it can never be increased after that.
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It is used as the RAM size in with U-Boot.
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choice
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prompt "EFI 32/64-bit selection"
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depends on EFI_STUB
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help
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EFI does not support mixing 32-bit and 64-bit modes. This is a
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significant problem because it means that you must build a stub with
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the correct type for EFI to load it correctly. If you are using
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32-bit EFI, select 32-bit here, else select 64-bit. Failure to do
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this may produce no error message - it just won't start!
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config EFI_STUB_32BIT
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bool "Produce a stub for running with 32-bit EFI"
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config EFI_STUB_64BIT
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bool "Produce a stub for running with 64-bit EFI"
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endchoice
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