[sw/flash] Update flash lib and test

Signed-off-by: Timothy Chen <timothytim@google.com>

[sw] update flash function name

Signed-off-by: Timothy Chen <timothytim@google.com>
diff --git a/sw/device/lib/flash_ctrl.c b/sw/device/lib/flash_ctrl.c
index a1419e1..8633f56 100644
--- a/sw/device/lib/flash_ctrl.c
+++ b/sw/device/lib/flash_ctrl.c
@@ -3,9 +3,10 @@
 // SPDX-License-Identifier: Apache-2.0
 #include "sw/device/lib/flash_ctrl.h"
 
+#include "sw/device/lib/common.h"
+
 #include "flash_ctrl_regs.h"  // Generated.
 #include "hw/top_earlgrey/sw/autogen/top_earlgrey.h"
-#include "sw/device/lib/common.h"
 
 #define FLASH_CTRL0_BASE_ADDR TOP_EARLGREY_FLASH_CTRL_BASE_ADDR
 
@@ -131,6 +132,10 @@
   return get_clr_err();
 }
 
+void flash_cfg_scramble_enable(bool en) {
+  REG32(FLASH_CTRL_SCRAMBLE_EN(0)) = en & 1;
+}
+
 void flash_cfg_bank_erase(bank_index_t bank, bool erase_en) {
   REG32(FLASH_CTRL_MP_BANK_CFG(0)) =
       (erase_en) ? SETBIT(REG32(FLASH_CTRL_MP_BANK_CFG(0)), bank)
diff --git a/sw/device/lib/flash_ctrl.h b/sw/device/lib/flash_ctrl.h
index ed8f974..00b6640 100644
--- a/sw/device/lib/flash_ctrl.h
+++ b/sw/device/lib/flash_ctrl.h
@@ -97,6 +97,11 @@
 void flash_cfg_bank_erase(bank_index_t bank, bool erase_en);
 
 /**
+ * Configure scramble enable
+ */
+void flash_cfg_scramble_enable(bool en);
+
+/**
  * Set flash controller default permissions.
  *
  * @param rd_end Read enable.
diff --git a/sw/device/tests/flash_ctrl_test.c b/sw/device/tests/flash_ctrl_test.c
index 9b003d2..e669c1e 100644
--- a/sw/device/tests/flash_ctrl_test.c
+++ b/sw/device/tests/flash_ctrl_test.c
@@ -179,6 +179,7 @@
 
   LOG_INFO("flash test!");
 
+  flash_cfg_scramble_enable(true);
   flash_cfg_bank_erase(FLASH_BANK_0, /*erase_en=*/true);
   flash_cfg_bank_erase(FLASH_BANK_1, /*erase_en=*/true);