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u-boot/arch/arm/cpu/armv8/spin_table_v8.S

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SPDX: Convert all of our single license tags to Linux Kernel style 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>
2018-05-06 21:58:06 +00:00
/* SPDX-License-Identifier: GPL-2.0+ */
arm64: add better and more generic spin-table support There are two enable methods supported by ARM64 Linux; psci and spin-table. The latter is simpler and helpful for quick SoC bring up. My main motivation for this patch is to improve the spin-table support, which allows us to boot an ARMv8 system without the ARM Trusted Firmware. Currently, we have multi-entry code in arch/arm/cpu/armv8/start.S and the spin-table is supported in a really ad-hoc way, and I see some problems: - We must hard-code CPU_RELEASE_ADDR so that it matches the "cpu-release-addr" property in the DT that comes from the kernel tree. - The Documentation/arm64/booting.txt in Linux requires that the release address must be zero-initialized, but it is not cared by the common code in U-Boot. We must do it in a board function. - There is no systematic way to protect the spin-table code from the kernel. We are supposed to do it in a board specific manner, but it is difficult to predict where the spin-table code will be located after the relocation. So, it also makes difficult to hard-code /memreserve/ in the DT of the kernel. So, here is a patch to solve those problems; the DT is run-time modified to reserve the spin-table code (+ cpu-release-addr). Also, the "cpu-release-addr" property is set to an appropriate address after the relocation, which means we no longer need the hard-coded CPU_RELEASE_ADDR. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2016-06-27 10:31:05 +00:00
/*
* Copyright (C) 2016 Socionext Inc.
* Author: Masahiro Yamada <yamada.masahiro@socionext.com>
*/
#include <linux/linkage.h>
ENTRY(spin_table_secondary_jump)
.globl spin_table_reserve_begin
spin_table_reserve_begin:
0: wfe
ldr x0, spin_table_cpu_release_addr
cbz x0, 0b
br x0
.globl spin_table_cpu_release_addr
.align 3
spin_table_cpu_release_addr:
.quad 0
.globl spin_table_reserve_end
spin_table_reserve_end:
ENDPROC(spin_table_secondary_jump)
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