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arch/arm: introduce generic FPU internal option

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Currently, we consider that any VFP FPU is a superset of VFPv2, and thus
we use VFPv2 as a way to detect that a VFP is used.

However, for Cortex-M cores, the optional FPU is not a superset of
VFPv2; it is even not a VFP [0].

As a consequence, we can no longer consider VFPv2 as a indication that
an FPU is present.

So, we introduce two new internal options, BR2_ARM_CPU_MAYBE_HAS_FPU and
BR2_ARM_CPU_HAS_FPU, which we use to consider the presence of an FPU.

[0] https://en.wikipedia.org/wiki/ARM_Cortex-M#Cortex-M4

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
This commit is contained in:
Yann E. MORIN 2018-02-25 21:18:14 +01:00 committed by Thomas Petazzoni
parent 6edfa3bf78
commit 7f7701301e
1 changed files with 13 additions and 4 deletions
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17
arch/Config.in.arm
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@ -6,12 +6,21 @@ config BR2_ARM_CPU_HAS_NEON
config BR2_ARM_CPU_MAYBE_HAS_NEON
bool
# For some cores, the FPU is optional
config BR2_ARM_CPU_MAYBE_HAS_FPU
bool
config BR2_ARM_CPU_HAS_FPU
bool
# for some cores, VFPv2 is optional
config BR2_ARM_CPU_MAYBE_HAS_VFPV2
bool
select BR2_ARM_CPU_MAYBE_HAS_FPU
config BR2_ARM_CPU_HAS_VFPV2
bool
select BR2_ARM_CPU_HAS_FPU
# for some cores, VFPv3 is optional
config BR2_ARM_CPU_MAYBE_HAS_VFPV3
@ -450,7 +459,7 @@ config BR2_ARM_ENABLE_NEON
config BR2_ARM_ENABLE_VFP
bool "Enable VFP extension support"
depends on BR2_ARM_CPU_MAYBE_HAS_VFPV2
depends on BR2_ARM_CPU_MAYBE_HAS_FPU
select BR2_ARM_CPU_HAS_VFPV4 if BR2_ARM_CPU_MAYBE_HAS_VFPV4
select BR2_ARM_CPU_HAS_VFPV3 if BR2_ARM_CPU_MAYBE_HAS_VFPV3
select BR2_ARM_CPU_HAS_VFPV2 if BR2_ARM_CPU_MAYBE_HAS_VFPV2
@ -461,7 +470,7 @@ config BR2_ARM_ENABLE_VFP
choice
prompt "Target ABI"
default BR2_ARM_EABIHF if BR2_ARM_CPU_HAS_VFPV2
default BR2_ARM_EABIHF if BR2_ARM_CPU_HAS_FPU
default BR2_ARM_EABI
depends on BR2_arm || BR2_armeb
help
@ -496,7 +505,7 @@ config BR2_ARM_EABI
config BR2_ARM_EABIHF
bool "EABIhf"
depends on BR2_ARM_CPU_HAS_VFPV2
depends on BR2_ARM_CPU_HAS_FPU
help
The EABIhf is an extension of EABI which supports the 'hard'
floating point model. This model uses the floating point
@ -520,7 +529,7 @@ choice
default BR2_ARM_FPU_VFPV4D16 if BR2_ARM_CPU_HAS_VFPV4
default BR2_ARM_FPU_VFPV3D16 if BR2_ARM_CPU_HAS_VFPV3
default BR2_ARM_FPU_VFPV2 if BR2_ARM_CPU_HAS_VFPV2
default BR2_ARM_SOFT_FLOAT if !BR2_ARM_CPU_HAS_VFPV2
default BR2_ARM_SOFT_FLOAT if !BR2_ARM_CPU_HAS_FPU
config BR2_ARM_SOFT_FLOAT
bool "Soft float"