[Buildroot] [PATCH next 1/4] arch/arm: add the Neoverse-V1 core

[Julien Olivain]

This commit adds the Neoverse-V1 core, which is an armv8.4a ISA.
See: [1] [2].

This CPU support was added in GCC 11. See [3] [4] [5].

This CPU supports Aarch64 at all exception levels (EL0 to EL3).
It also supports Aarch32 only in EL0 (user-space). This means it's
technically possible to compile Aarch32 code. GCC has the support
to do so. Since Buildroot recompiles a full system (ATF, Kernel,
user-space) this support has limited value. This is why this
CPU is limited to 64bit builds only.

Qemu added neoverse-v1 support in upstream commit [6], first included
in v8.1.0.

[1] https://developer.arm.com/Processors/Neoverse%20V1
[2] https://developer.arm.com/documentation/101427/0102/Functional-description/Introduction/About-the-core
[3] https://gcc.gnu.org/gcc-11/changes.html#arm-targets
[4] https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/config/aarch64/aarch64-cores.def;hb=releases/gcc-11.1.0#l141
[5] https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=c9d56eb777552ac5ee0c281e1f6e34b6fe929b77
[6] https://gitlab.com/qemu-project/qemu/-/commit/c74138c6c040b62e941326a4fbb25a93fdd35b72

Signed-off-by: Julien Olivain <ju.o at free.fr>
---
 arch/Config.in.arm | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/Config.in.arm b/arch/Config.in.arm
index a0bf6c3386..16911f5b95 100644
--- a/arch/Config.in.arm
+++ b/arch/Config.in.arm
@@ -498,6 +498,12 @@ config BR2_tsv110
 	select BR2_ARCH_NEEDS_GCC_AT_LEAST_9
 
 comment "armv8.4a cores"
+config BR2_neoverse_v1
+	bool "neoverse-V1 (aka zeus)"
+	depends on BR2_ARCH_IS_64
+	select BR2_ARM_CPU_HAS_FP_ARMV8
+	select BR2_ARM_CPU_ARMV8A
+	select BR2_ARCH_NEEDS_GCC_AT_LEAST_11
 config BR2_saphira
 	bool "saphira"
 	depends on BR2_ARCH_IS_64
@@ -918,6 +924,7 @@ config BR2_GCC_TARGET_CPU
 	default "neoverse-n1"	if BR2_neoverse_n1
 	default "tsv110"	if BR2_tsv110
 	# armv8.4a
+	default "neoverse-v1"   if BR2_neoverse_v1
 	default "saphira"	if BR2_saphira
 	# armv9.0a
 	default "cortex-a710"	if BR2_cortex_a710
-- 
2.53.0