[Buildroot] [PATCH 2/6] arch/arm: introduce generic FPU internal option
Yann E. MORIN
yann.morin.1998 at free.fr
Sun Feb 25 20:18:14 UTC 2018
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 at free.fr>
---
arch/Config.in.arm | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/arch/Config.in.arm b/arch/Config.in.arm
index 67f8a16737..89db5fad08 100644
--- a/arch/Config.in.arm
+++ b/arch/Config.in.arm
@@ -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
@@ -462,7 +471,7 @@ config BR2_ARM_ENABLE_VFP
choice
prompt "Target ABI"
depends on BR2_arm || BR2_armeb
- default BR2_ARM_EABIHF if BR2_ARM_CPU_HAS_VFPV2
+ default BR2_ARM_EABIHF if BR2_ARM_CPU_HAS_FPU
default BR2_ARM_EABI
help
Application Binary Interface to use. The Application Binary
@@ -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"
--
2.14.1
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