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https://github.com/brain-hackers/u-boot-brain
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45f41c134b
When booting from ARM Trusted Firmware, U-Boot runs in EL1-NS. The boot flow is as follows: BL1 -> BL2 -> BL31 -> BL33 (i.e. U-Boot) This boot sequence works fine for LD11 SoC (Cortex-A53), but LD20 SoC (Cortex-A72) hangs in U-Boot. The solution I found is to read sctlr_el1 and write back the value as-is. This should be no effect, but surprisingly fixes the problem for LD20 to boot. I do not know why. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
15 lines
266 B
ArmAsm
15 lines
266 B
ArmAsm
/*
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* Copyright (C) 2017 Socionext Inc.
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <linux/linkage.h>
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ENTRY(lowlevel_init)
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/* LD20 needs the following code to boot. I do not know why. */
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mrs x0, sctlr_el1
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msr sctlr_el1, x0
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ret
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ENDPROC(lowlevel_init)
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