From 605493d50877c41776faddd447dfddbd78f97647 Mon Sep 17 00:00:00 2001
From: Christian Walther <cwalther@gmx.ch>
Date: Wed, 3 May 2023 22:45:43 +0200
Subject: [PATCH] examples/embedding-full: Add example user C module.

This works out of the box in the embed port.

Signed-off-by: Christian Walther <cwalther@gmx.ch>
---
 examples/embedding-full/Makefile              |  2 +-
 examples/embedding-full/main.c                |  3 +++
 examples/embedding-full/micropython_embed.mk  |  3 +++
 .../modules/c_hello/micropython.mk            |  2 ++
 .../modules/c_hello/modc_hello.c              | 23 +++++++++++++++++++
 5 files changed, 32 insertions(+), 1 deletion(-)
 create mode 100644 examples/embedding-full/modules/c_hello/micropython.mk
 create mode 100644 examples/embedding-full/modules/c_hello/modc_hello.c

diff --git a/examples/embedding-full/Makefile b/examples/embedding-full/Makefile
index 3e696857fd..b0ce3daf14 100644
--- a/examples/embedding-full/Makefile
+++ b/examples/embedding-full/Makefile
@@ -14,7 +14,7 @@ CFLAGS += -I$(EMBED_DIR)
 CFLAGS += -I$(EMBED_DIR)/port
 CFLAGS += -Wall -Og -fno-common
 
-SRC += main.c mphal.c
+SRC += main.c mphal.c modules/c_hello/modc_hello.c
 SRC += $(wildcard $(EMBED_DIR)/*/*.c)
 # Filter out lib because the files in there cannot be compiled separately, they
 # are #included by other .c files.
diff --git a/examples/embedding-full/main.c b/examples/embedding-full/main.c
index a24760afdb..73d7ebf45f 100644
--- a/examples/embedding-full/main.c
+++ b/examples/embedding-full/main.c
@@ -37,6 +37,9 @@ static const char *example_2 =
     "import frozenhello\n"
     "help(frozenhello)\n"
     "print('frozenhello.hello():', frozenhello.hello())\n"
+    "import c_hello\n"
+    "help(c_hello)\n"
+    "print('c_hello.hello():', c_hello.hello())\n"
     "\n"
     "print('finish')\n"
     ;
diff --git a/examples/embedding-full/micropython_embed.mk b/examples/embedding-full/micropython_embed.mk
index ee96a5f486..d4e76b609b 100644
--- a/examples/embedding-full/micropython_embed.mk
+++ b/examples/embedding-full/micropython_embed.mk
@@ -11,5 +11,8 @@ EMBED_EXTRA = extmod
 # Freeze Python modules.
 FROZEN_MANIFEST ?= manifest.py
 
+# Add C modules.
+USER_C_MODULES = modules
+
 # Include the main makefile fragment to build the MicroPython component.
 include $(MICROPYTHON_TOP)/ports/embed/embed.mk
diff --git a/examples/embedding-full/modules/c_hello/micropython.mk b/examples/embedding-full/modules/c_hello/micropython.mk
new file mode 100644
index 0000000000..7d610d1edd
--- /dev/null
+++ b/examples/embedding-full/modules/c_hello/micropython.mk
@@ -0,0 +1,2 @@
+C_HELLO_MOD_DIR := $(USERMOD_DIR)
+SRC_USERMOD_C += $(C_HELLO_MOD_DIR)/modc_hello.c
diff --git a/examples/embedding-full/modules/c_hello/modc_hello.c b/examples/embedding-full/modules/c_hello/modc_hello.c
new file mode 100644
index 0000000000..548c7a3349
--- /dev/null
+++ b/examples/embedding-full/modules/c_hello/modc_hello.c
@@ -0,0 +1,23 @@
+// Check examples/usercmodule for more info about how this works.
+
+#include "py/runtime.h"
+#include "py/objstr.h"
+
+static mp_obj_t c_hello_hello() {
+    static const MP_DEFINE_STR_OBJ(hello_str, "Hello from C!");
+    return MP_OBJ_FROM_PTR(&hello_str);
+}
+static MP_DEFINE_CONST_FUN_OBJ_0(c_hello_hello_obj, c_hello_hello);
+
+static const mp_rom_map_elem_t c_hello_module_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_c_hello) },
+    { MP_ROM_QSTR(MP_QSTR_hello), MP_ROM_PTR(&c_hello_hello_obj) },
+};
+static MP_DEFINE_CONST_DICT(c_hello_module_globals, c_hello_module_globals_table);
+
+const mp_obj_module_t c_hello_module = {
+    .base = { &mp_type_module },
+    .globals = (mp_obj_dict_t *)&c_hello_module_globals,
+};
+
+MP_REGISTER_MODULE(MP_QSTR_c_hello, c_hello_module);