tree 1dbf1feb70c4dbc8636b87f0fdb83766f0bac6e8
parent 6a60461ef85aee5b33f2a4c330acd790249fe456
author johpow01 <john.powell@arm.com> 1587582313 -0500
committer John <john.powell@arm.com> 1589924992 +0000

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