[sw/silicon_creator] Remove retention SRAM errors Signed-off-by: Alphan Ulusoy <alphan@google.com>

diff --git a/sw/device/silicon_creator/lib/drivers/retention_sram.c b/sw/device/silicon_creator/lib/drivers/retention_sram.c
index 6f1125e..1a2e858 100644
--- a/sw/device/silicon_creator/lib/drivers/retention_sram.c
+++ b/sw/device/silicon_creator/lib/drivers/retention_sram.c

@@ -18,21 +18,6 @@
   kBase = TOP_EARLGREY_SRAM_CTRL_RET_AON_REGS_BASE_ADDR,
 };
 
-/**
- * Check that control register writes are enabled.
- *
- * @return Result of the operation.
- */
-static rom_error_t is_locked(void) {
-  if (!bitfield_bit32_read(
-          abs_mmio_read32(kBase + SRAM_CTRL_CTRL_REGWEN_REG_OFFSET),
-          SRAM_CTRL_CTRL_REGWEN_CTRL_REGWEN_BIT)) {
-    return kErrorRetSramLocked;
-  }
-
-  return kErrorOk;
-}
-
 volatile retention_sram_t *retention_sram_get(void) {
   static_assert(sizeof(retention_sram_t) == TOP_EARLGREY_RAM_RET_AON_SIZE_BYTES,
                 "Unexpected retention SRAM size.");
@@ -43,24 +28,16 @@
   *retention_sram_get() = (retention_sram_t){0};
 }
 
-rom_error_t retention_sram_init(void) {
-  RETURN_IF_ERROR(is_locked());
-
+void retention_sram_init(void) {
   uint32_t reg = bitfield_bit32_write(0, SRAM_CTRL_CTRL_INIT_BIT, true);
   abs_mmio_write32(kBase + SRAM_CTRL_CTRL_REG_OFFSET, reg);
-
-  return kErrorOk;
 }
 
-rom_error_t retention_sram_scramble(void) {
-  RETURN_IF_ERROR(is_locked());
-
+void retention_sram_scramble(void) {
   // Request the renewal of the scrambling key and initialization to random
   // values.
   uint32_t ctrl = 0;
   ctrl = bitfield_bit32_write(ctrl, SRAM_CTRL_CTRL_RENEW_SCR_KEY_BIT, true);
   ctrl = bitfield_bit32_write(ctrl, SRAM_CTRL_CTRL_INIT_BIT, true);
   abs_mmio_write32(kBase + SRAM_CTRL_CTRL_REG_OFFSET, ctrl);
-
-  return kErrorOk;
 }

diff --git a/sw/device/silicon_creator/lib/drivers/retention_sram.h b/sw/device/silicon_creator/lib/drivers/retention_sram.h
index ce282bd..895daf1 100644
--- a/sw/device/silicon_creator/lib/drivers/retention_sram.h
+++ b/sw/device/silicon_creator/lib/drivers/retention_sram.h

@@ -66,7 +66,7 @@
  *
  * @return Result of the operation.
  */
-rom_error_t retention_sram_init(void);
+void retention_sram_init(void);
 
 /**
  * Start scrambling the retention SRAM.
@@ -80,7 +80,7 @@
  *
  * @return An error if a new key cannot be requested.
  */
-rom_error_t retention_sram_scramble(void);
+void retention_sram_scramble(void);
 
 #ifdef __cplusplus
 }

diff --git a/sw/device/silicon_creator/lib/drivers/retention_sram_functest.c b/sw/device/silicon_creator/lib/drivers/retention_sram_functest.c
index e244897..9def87d 100644
--- a/sw/device/silicon_creator/lib/drivers/retention_sram_functest.c
+++ b/sw/device/silicon_creator/lib/drivers/retention_sram_functest.c

@@ -45,10 +45,7 @@
 
   // Scramble the retention SRAM.
   LOG_INFO("Scrambling retention SRAM.");
-  if (retention_sram_scramble() != kErrorOk) {
-    LOG_ERROR("Scrambling failed.");
-    return kErrorUnknown;
-  }
+  retention_sram_scramble();
 
   // Copy the contents of the retention SRAM into an array of 64-bit integers.
   // We use 64-bit integers rather than 32-bit integers to reduce the

diff --git a/sw/device/silicon_creator/lib/drivers/retention_sram_unittest.cc b/sw/device/silicon_creator/lib/drivers/retention_sram_unittest.cc
index da11212..b3d5388 100644
--- a/sw/device/silicon_creator/lib/drivers/retention_sram_unittest.cc
+++ b/sw/device/silicon_creator/lib/drivers/retention_sram_unittest.cc

@@ -23,44 +23,24 @@
 class ScrambleTest : public RetentionSramTest {};
 
 TEST_F(ScrambleTest, Ok) {
-  EXPECT_ABS_READ32(base_ + SRAM_CTRL_CTRL_REGWEN_REG_OFFSET,
-                    {
-                        {SRAM_CTRL_CTRL_REGWEN_CTRL_REGWEN_BIT, 1},
-                    });
   EXPECT_ABS_WRITE32(base_ + SRAM_CTRL_CTRL_REG_OFFSET,
                      {
                          {SRAM_CTRL_CTRL_RENEW_SCR_KEY_BIT, 1},
                          {SRAM_CTRL_CTRL_INIT_BIT, 1},
                      });
 
-  EXPECT_EQ(retention_sram_scramble(), kErrorOk);
-}
-
-TEST_F(ScrambleTest, Locked) {
-  EXPECT_ABS_READ32(base_ + SRAM_CTRL_CTRL_REGWEN_REG_OFFSET, 0);
-
-  EXPECT_EQ(retention_sram_scramble(), kErrorRetSramLocked);
+  retention_sram_scramble();
 }
 
 class InitTest : public RetentionSramTest {};
 
 TEST_F(InitTest, Ok) {
-  EXPECT_ABS_READ32(base_ + SRAM_CTRL_CTRL_REGWEN_REG_OFFSET,
-                    {
-                        {SRAM_CTRL_CTRL_REGWEN_CTRL_REGWEN_BIT, 1},
-                    });
   EXPECT_ABS_WRITE32(base_ + SRAM_CTRL_CTRL_REG_OFFSET,
                      {
                          {SRAM_CTRL_CTRL_INIT_BIT, 1},
                      });
 
-  EXPECT_EQ(retention_sram_init(), kErrorOk);
-}
-
-TEST_F(InitTest, Locked) {
-  EXPECT_ABS_READ32(base_ + SRAM_CTRL_CTRL_REGWEN_REG_OFFSET, 0);
-
-  EXPECT_EQ(retention_sram_init(), kErrorRetSramLocked);
+  retention_sram_init();
 }
 
 }  // namespace

diff --git a/sw/device/silicon_creator/lib/error.h b/sw/device/silicon_creator/lib/error.h
index cfa6ddb..49d80c6 100644
--- a/sw/device/silicon_creator/lib/error.h
+++ b/sw/device/silicon_creator/lib/error.h

@@ -36,7 +36,6 @@
   kModuleOtbn =         MODULE_CODE('B', 'N'),
   kModuleFlashCtrl =    MODULE_CODE('F', 'C'),
   kModuleBootPolicy =   MODULE_CODE('B', 'P'),
-  kModuleRetSram =      MODULE_CODE('R', 'S'),
   kModuleBootstrap =    MODULE_CODE('B', 'S'),
   kModuleLog =          MODULE_CODE('L', 'G'),
   kModuleBootData =     MODULE_CODE('B', 'D'),
@@ -101,7 +100,6 @@
   X(kErrorBootPolicyBadIdentifier,    ERROR_(1, kModuleBootPolicy, kInternal)), \
   X(kErrorBootPolicyBadLength,        ERROR_(2, kModuleBootPolicy, kInternal)), \
   X(kErrorBootPolicyRollback,         ERROR_(3, kModuleBootPolicy, kInternal)), \
-  X(kErrorRetSramLocked,              ERROR_(1, kModuleRetSram, kInternal)), \
   X(kErrorBootstrapEraseAddress,      ERROR_(1, kModuleBootstrap, kInvalidArgument)), \
   X(kErrorBootstrapProgramAddress,    ERROR_(2, kModuleBootstrap, kInvalidArgument)), \
   X(kErrorBootstrapInvalidState,      ERROR_(3, kModuleBootstrap, kInvalidArgument)), \