commit be105cf1dae3fe7e7261a12e19f91eeae1f284d1
author Michael Munday <mike.munday@lowrisc.org> Tue Dec 14 17:06:00 2021 -0500
committer Alphan Ulusoy <alphan@google.com> Wed Dec 15 09:45:42 2021 -0500
tree a4bc767d4509939d459136ffa122efc9c129d7fd
parent 486318ab23b55a88a5f34a06e3a7fc54193cfbfd

[sw/silicon_creator] Disable flash in pre-CRT exception handler

Signed-off-by: Michael Munday <mike.munday@lowrisc.org>

sw/device/silicon_creator/lib/irq_asm.S

diff --git a/sw/device/silicon_creator/lib/irq_asm.S b/sw/device/silicon_creator/lib/irq_asm.S
index 7c98740..29af854 100644
--- a/sw/device/silicon_creator/lib/irq_asm.S
+++ b/sw/device/silicon_creator/lib/irq_asm.S
@@ -4,6 +4,7 @@
 
 #include "sw/device/lib/base/multibits_asm.h"
 #include "hw/top_earlgrey/sw/autogen/top_earlgrey_memory.h"
+#include "flash_ctrl_regs.h"
 #include "rstmgr_regs.h"
 
   // This code is in the .crt section since it is designed to be safe
@@ -27,6 +28,13 @@
   li t1, MULTIBIT_ASM_BOOL4_TRUE
   sw t1, RSTMGR_RESET_REQ_REG_OFFSET(t0)
 
+  // Disable access to flash.
+  //
+  // This is done after requesting a reset so that this function will
+  // work even if it is in flash.
+  li t0, TOP_EARLGREY_FLASH_CTRL_CORE_BASE_ADDR
+  sw zero, FLASH_CTRL_DIS_REG_OFFSET(t0)
+
   // Enter a wait for interrupt loop, the device should reset shortly.
 .L_wfi_loop:
   wfi

sw/device/silicon_creator/lib/meson.build

diff --git a/sw/device/silicon_creator/lib/meson.build b/sw/device/silicon_creator/lib/meson.build
index 231eced..0a2e7c8 100644
--- a/sw/device/silicon_creator/lib/meson.build
+++ b/sw/device/silicon_creator/lib/meson.build
@@ -144,6 +144,7 @@
     'sw_silicon_creator_lib_irq_asm',
     sources: [
       hw_ip_rstmgr_reg_h,
+      hw_ip_flash_ctrl_reg_h,
       'irq_asm.S',
     ],
   ),