From 0f5589d16fbc3b938d5ae2e1b5a950a33de7f647 Mon Sep 17 00:00:00 2001
From: Chia-Wei Liu <lchiawei@google.com>
Date: Tue, 3 Dec 2024 03:51:44 +0800
Subject: [PATCH] [imm_rom_ext] Link main imm_rom_ext into rom_ext

Remove calling imm_rom_ext_main in rom_ext_main, and use prebuilt
IMM_ROM_EXT instead.

Signed-off-by: Chia-Wei Liu <lchiawei@google.com>
---
 sw/device/silicon_creator/imm_rom_ext/BUILD   | 27 ++++++++++++++++++-
 .../silicon_creator/imm_rom_ext/defs.bzl      |  3 +--
 sw/device/silicon_creator/rom_ext/BUILD       |  2 +-
 sw/device/silicon_creator/rom_ext/rom_ext.c   | 13 ---------
 4 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/sw/device/silicon_creator/imm_rom_ext/BUILD b/sw/device/silicon_creator/imm_rom_ext/BUILD
index 51587a60f0d95..d9fc0223991aa 100644
--- a/sw/device/silicon_creator/imm_rom_ext/BUILD
+++ b/sw/device/silicon_creator/imm_rom_ext/BUILD
@@ -11,8 +11,12 @@ package(default_visibility = ["//visibility:public"])
 
 cc_library(
     name = "main_lib",
-    srcs = ["imm_rom_ext.c"],
+    srcs = [
+        "hello_world_start.S",
+        "imm_rom_ext.c",
+    ],
     hdrs = ["imm_rom_ext.h"],
+    target_compatible_with = [OPENTITAN_CPU],
     deps = [
         ":imm_rom_ext_epmp",
         "//hw/top:flash_ctrl_c_regs",
@@ -51,6 +55,27 @@ cc_library(
     ],
 )
 
+opentitan_binary(
+    name = "main_binaries",
+    # TODO(#24368): Support multiple executing environments. Currently all
+    # environments derive the same binary so only one environment is kept here,
+    # but we need to support multiple executing environments and make sure
+    # ROM_EXT targets choose the matched environment when linking IMM_ROM_EXT.
+    exec_env = [
+        "//hw/top_earlgrey:fpga_cw340",
+    ],
+    linker_script = ":ld_hello_world",
+    deps = [
+        ":main_lib",
+        "//sw/device/lib/crt",
+    ],
+)
+
+imm_rom_ext_section(
+    name = "main_section",
+    srcs = [":main_binaries"],
+)
+
 ld_library(
     name = "ld_hello_world",
     script = "hello_world.ld",
diff --git a/sw/device/silicon_creator/imm_rom_ext/defs.bzl b/sw/device/silicon_creator/imm_rom_ext/defs.bzl
index 04ada7e14b651..ad4f98675cac8 100644
--- a/sw/device/silicon_creator/imm_rom_ext/defs.bzl
+++ b/sw/device/silicon_creator/imm_rom_ext/defs.bzl
@@ -4,6 +4,5 @@
 
 # The target list should contian prebuilt artifacts and run-time build targets.
 IMM_ROM_EXT_TARGETS = {
-    "nop": "//sw/device/silicon_creator/imm_rom_ext/prebuilts:nop_imm_rom_ext",
-    "hello_world": "//sw/device/silicon_creator/imm_rom_ext:hello_world_section",
+    "main": "//sw/device/silicon_creator/imm_rom_ext:main_section",
 }
diff --git a/sw/device/silicon_creator/rom_ext/BUILD b/sw/device/silicon_creator/rom_ext/BUILD
index 97b9bc066606f..c994ede35fbe4 100644
--- a/sw/device/silicon_creator/rom_ext/BUILD
+++ b/sw/device/silicon_creator/rom_ext/BUILD
@@ -233,7 +233,7 @@ cc_library(
         "//sw/device/lib/base:memory",
         "//sw/device/lib/base:stdasm",
         "//sw/device/lib/runtime:hart",
-        "//sw/device/silicon_creator/imm_rom_ext:main_lib",
+        "//sw/device/silicon_creator/imm_rom_ext:main_section",
         "//sw/device/silicon_creator/lib:boot_data",
         "//sw/device/silicon_creator/lib:boot_log",
         "//sw/device/silicon_creator/lib:dbg_print",
diff --git a/sw/device/silicon_creator/rom_ext/rom_ext.c b/sw/device/silicon_creator/rom_ext/rom_ext.c
index c9df0d54c3cad..1cd63a1f2ee09 100644
--- a/sw/device/silicon_creator/rom_ext/rom_ext.c
+++ b/sw/device/silicon_creator/rom_ext/rom_ext.c
@@ -10,7 +10,6 @@
 #include "sw/device/lib/base/memory.h"
 #include "sw/device/lib/base/stdasm.h"
 #include "sw/device/lib/runtime/hart.h"
-#include "sw/device/silicon_creator/imm_rom_ext/imm_rom_ext.h"
 #include "sw/device/silicon_creator/lib/base/boot_measurements.h"
 #include "sw/device/silicon_creator/lib/base/chip.h"
 #include "sw/device/silicon_creator/lib/base/sec_mmio.h"
@@ -602,11 +601,6 @@ static rom_error_t rom_ext_start(boot_data_t *boot_data, boot_log_t *boot_log) {
 }
 
 void rom_ext_main(void) {
-  // TODO(opentitan#24368): Call immutable main in .rom_ext_immutable.
-  // The immutable rom_ext startup code is not ready yet, so we call it here
-  // to avoid breaking tests.
-  imm_rom_ext_main();
-
   rom_ext_check_rom_expectations();
   boot_data_t boot_data;
   boot_log_t *boot_log = &retention_sram_get()->creator.boot_log;
@@ -632,10 +626,3 @@ void rom_ext_exception_handler(void);
 OT_USED
 OT_ALIAS("rom_ext_interrupt_handler")
 void rom_ext_nmi_handler(void);
-
-// A no-op immutable rom_ext fallback to avoid breaking tests before the
-// proper bazel target is ready.
-// TODO(opentitan#24368): Remove this nop fallback.
-OT_USED
-OT_SECTION(".rom_ext_immutable.fallback")
-void imm_rom_ext_placeholder(void) {}