Enable v8.6 WFE trap delays
This patch enables the v8.6 extension to add a delay before WFE traps
are taken. A weak hook plat_arm_set_twedel_scr_el3 has been added in
plat/common/aarch64/plat_common.c that disables this feature by default
but platform-specific code can override it when needed.
The only hook provided sets the TWED fields in SCR_EL3, there are similar
fields in HCR_EL2, SCTLR_EL2, and SCTLR_EL1 to control WFE trap delays in
lower ELs but these should be configured by code running at EL2 and/or EL1
depending on the platform configuration and is outside the scope of TF-A.
Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: I0a9bb814205efeab693a3d0a0623e62144abba2d
diff --git a/include/arch/aarch64/arch_features.h b/include/arch/aarch64/arch_features.h
index 9513e97..49d827d 100644
--- a/include/arch/aarch64/arch_features.h
+++ b/include/arch/aarch64/arch_features.h
@@ -58,4 +58,10 @@
ID_AA64PFR0_SEL2_MASK) == 1ULL;
}
+static inline bool is_armv8_6_twed_present(void)
+{
+ return (((read_id_aa64mmfr1_el1() >> ID_AA64MMFR1_EL1_TWED_SHIFT) &
+ ID_AA64MMFR1_EL1_TWED_MASK) == ID_AA64MMFR1_EL1_TWED_SUPPORTED);
+}
+
#endif /* ARCH_FEATURES_H */