refactor(twed): improve TWED enablement in EL-3
The current implementation uses plat_arm API under generic code.
"plat_arm" API is a convention used with Arm common platform layer
and is reserved for that purpose. In addition, the function has a
weak definition which is not encouraged in TF-A.
Henceforth, removing the weak API with a configurable macro "TWED_DELAY"
of numeric data type in generic code and simplifying the implementation.
By default "TWED_DELAY" is defined to zero, and the delay value need to
be explicitly set by the platforms during buildtime.
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
Change-Id: I25cd6f628e863dc40415ced3a82d0662fdf2d75a
diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index 459ca2c..47e7d8c 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -27,11 +27,14 @@
#include <lib/extensions/sys_reg_trace.h>
#include <lib/extensions/trbe.h>
#include <lib/extensions/trf.h>
-#include <lib/extensions/twed.h>
#include <lib/utils.h>
-static void manage_extensions_secure(cpu_context_t *ctx);
+#if ENABLE_FEAT_TWED
+/* Make sure delay value fits within the range(0-15) */
+CASSERT(((TWED_DELAY & ~SCR_TWEDEL_MASK) == 0U), assert_twed_delay_value_check);
+#endif /* ENABLE_FEAT_TWED */
+static void manage_extensions_secure(cpu_context_t *ctx);
/******************************************************************************
* This function performs initializations that are specific to SECURE state
* and updates the cpu context specified by 'ctx'.
@@ -329,23 +332,16 @@
sctlr_elx |= SCTLR_IESB_BIT;
#endif
+#if ENABLE_FEAT_TWED
/* Enable WFE trap delay in SCR_EL3 if supported and configured */
- if (is_armv8_6_twed_present()) {
- uint32_t delay = plat_arm_set_twedel_scr_el3();
+ /* Set delay in SCR_EL3 */
+ scr_el3 &= ~(SCR_TWEDEL_MASK << SCR_TWEDEL_SHIFT);
+ scr_el3 |= ((TWED_DELAY & SCR_TWEDEL_MASK)
+ << SCR_TWEDEL_SHIFT);
- if (delay != TWED_DISABLED) {
- /* Make sure delay value fits */
- assert((delay & ~SCR_TWEDEL_MASK) == 0U);
-
- /* Set delay in SCR_EL3 */
- scr_el3 &= ~(SCR_TWEDEL_MASK << SCR_TWEDEL_SHIFT);
- scr_el3 |= ((delay & SCR_TWEDEL_MASK)
- << SCR_TWEDEL_SHIFT);
-
- /* Enable WFE delay */
- scr_el3 |= SCR_TWEDEn_BIT;
- }
- }
+ /* Enable WFE delay */
+ scr_el3 |= SCR_TWEDEn_BIT;
+#endif /* ENABLE_FEAT_TWED */
/*
* Store the initialised SCTLR_EL1 value in the cpu_context - SCTLR_EL2