TBB: add Trusted Watchdog support on ARM platforms
This patch adds watchdog support on ARM platforms (FVP and Juno).
A secure instance of SP805 is used as Trusted Watchdog. It is
entirely managed in BL1, being enabled in the early platform setup
hook and disabled in the exit hook. By default, the watchdog is
enabled in every build (even when TBB is disabled).
A new ARM platform specific build option `ARM_DISABLE_TRUSTED_WDOG`
has been introduced to allow the user to disable the watchdog at
build time. This feature may be used for testing or debugging
purposes.
Specific error handlers for Juno and FVP are also provided in this
patch. These handlers will be called after an image load or
authentication error. On FVP, the Table of Contents (ToC) in the FIP
is erased. On Juno, the corresponding error code is stored in the
V2M Non-Volatile flags register. In both cases, the CPU spins until
a watchdog reset is generated after 256 seconds (as specified in
the TBBR document).
Change-Id: I9ca11dcb0fe15af5dbc5407ab3cf05add962f4b4
diff --git a/plat/arm/common/arm_bl1_setup.c b/plat/arm/common/arm_bl1_setup.c
index 887223c..79c7d94 100644
--- a/plat/arm/common/arm_bl1_setup.c
+++ b/plat/arm/common/arm_bl1_setup.c
@@ -35,6 +35,7 @@
#include <console.h>
#include <platform_def.h>
#include <plat_arm.h>
+#include <sp805.h>
#include "../../../bl1/bl1_private.h"
@@ -74,6 +75,11 @@
{
const size_t bl1_size = BL1_RAM_LIMIT - BL1_RAM_BASE;
+#if !ARM_DISABLE_TRUSTED_WDOG
+ /* Enable watchdog */
+ sp805_start(ARM_SP805_TWDG_BASE, ARM_TWDG_LOAD_VAL);
+#endif
+
/* Initialize the console to provide early debug support */
console_init(PLAT_ARM_BOOT_UART_BASE, PLAT_ARM_BOOT_UART_CLK_IN_HZ,
ARM_CONSOLE_BAUDRATE);
@@ -147,6 +153,11 @@
void bl1_plat_prepare_exit(entry_point_info_t *ep_info)
{
+#if !ARM_DISABLE_TRUSTED_WDOG
+ /* Disable watchdog before leaving BL1 */
+ sp805_stop(ARM_SP805_TWDG_BASE);
+#endif
+
#ifdef EL3_PAYLOAD_BASE
/*
* Program the EL3 payload's entry point address into the CPUs mailbox