Add support for hardware and board initialisation overrides. (#8330)

* Add support for hardware and board initialisation overrides.

* qmk cformat.

* Add some documentation.

* Docs clarity.

* Make early_hardware_init_pre a no-op for now, until migrations occur.

* Doco update

* Make distinction between keyboard and ChibiOS board in docs

* Doc anchors.

* Update tmk_core/protocol/chibios/main.c

Co-Authored-By: Joel Challis <git@zvecr.com>

* Rework bootloader entry to be off by default, allow opting-in.

Co-authored-by: Joel Challis <git@zvecr.com>

3 files changed, 54 insertions, 5 deletions

diff --git a/tmk_core/protocol/chibios/init_hooks.h b/tmk_core/protocol/chibios/init_hooks.h
new file mode 100644
index 000000000..fffced913
--- /dev/null
+++ b/tmk_core/protocol/chibios/init_hooks.h
@@ -0,0 +1,5 @@
+#pragma once
+
+// Override the initialisation functions inside the ChibiOS board.c files
+#define __early_init __chibios_override___early_init
+#define boardInit __chibios_override_boardInit
diff --git a/tmk_core/protocol/chibios/main.c b/tmk_core/protocol/chibios/main.c
index 6479fd09d..61665eb6f 100644
--- a/tmk_core/protocol/chibios/main.c
+++ b/tmk_core/protocol/chibios/main.c
@@ -33,6 +33,11 @@
 #include "debug.h"
 #include "printf.h"
 
+#ifndef EARLY_INIT_PERFORM_BOOTLOADER_JUMP
+// Change this to be TRUE once we've migrated keyboards to the new init system
+#    define EARLY_INIT_PERFORM_BOOTLOADER_JUMP FALSE
+#endif
+
 #ifdef SLEEP_LED_ENABLE
 #    include "sleep_led.h"
 #endif
@@ -101,6 +106,39 @@ void midi_ep_task(void);
 //   }
 // }
 
+/* Early initialisation
+ */
+__attribute__((weak)) void early_hardware_init_pre(void) {
+#if EARLY_INIT_PERFORM_BOOTLOADER_JUMP
+    void enter_bootloader_mode_if_requested(void);
+    enter_bootloader_mode_if_requested();
+#endif  // EARLY_INIT_PERFORM_BOOTLOADER_JUMP
+}
+
+__attribute__((weak)) void early_hardware_init_post(void) {}
+
+__attribute__((weak)) void board_init(void) {}
+
+// This overrides what's normally in ChibiOS board definitions
+void __early_init(void) {
+    early_hardware_init_pre();
+
+    // This is the renamed equivalent of __early_init in the board.c file
+    void __chibios_override___early_init(void);
+    __chibios_override___early_init();
+
+    early_hardware_init_post();
+}
+
+// This overrides what's normally in ChibiOS board definitions
+void boardInit(void) {
+    // This is the renamed equivalent of boardInit in the board.c file
+    void __chibios_override_boardInit(void);
+    __chibios_override_boardInit();
+
+    board_init();
+}
+
 /* Main thread
  */
 int main(void) {
diff --git a/tmk_core/rules.mk b/tmk_core/rules.mk
index c1474a5c2..a66718cd2 100644
--- a/tmk_core/rules.mk
+++ b/tmk_core/rules.mk
@@ -223,6 +223,12 @@ $(foreach LOBJ, $(NO_LTO_OBJ), $(eval $(call NO_LTO,$(LOBJ))))
 
 MOVE_DEP = mv -f $(patsubst %.o,%.td,$@) $(patsubst %.o,%.d,$@)
 
+# For a ChibiOS build, ensure that the board files have the hook overrides injected
+define BOARDSRC_INJECT_HOOKS
+$(KEYBOARD_OUTPUT)/$(patsubst %.c,%.o,$(patsubst ./%,%,$1)): INIT_HOOK_CFLAGS += -include $(TOP_DIR)/tmk_core/protocol/chibios/init_hooks.h
+endef
+$(foreach LOBJ, $(BOARDSRC), $(eval $(call BOARDSRC_INJECT_HOOKS,$(LOBJ))))
+
 # Add QMK specific flags
 DFU_SUFFIX ?= dfu-suffix
 DFU_SUFFIX_ARGS ?=
@@ -306,27 +312,27 @@ ifdef $1_CONFIG
 $1_CONFIG_FLAGS += $$(patsubst %,-include %,$$($1_CONFIG))
 endif
 $1_CFLAGS = $$(ALL_CFLAGS) $$($1_DEFS) $$($1_INCFLAGS) $$($1_CONFIG_FLAGS) $$(NOLTO_CFLAGS)
-$1_CXXFLAGS= $$(ALL_CXXFLAGS) $$($1_DEFS) $$($1_INCFLAGS) $$($1_CONFIG_FLAGS) $$(NOLTO_CFLAGS)
-$1_ASFLAGS= $$(ALL_ASFLAGS) $$($1_DEFS) $$($1_INCFLAGS) $$($1_CONFIG_FLAGS)
+$1_CXXFLAGS = $$(ALL_CXXFLAGS) $$($1_DEFS) $$($1_INCFLAGS) $$($1_CONFIG_FLAGS) $$(NOLTO_CFLAGS)
+$1_ASFLAGS = $$(ALL_ASFLAGS) $$($1_DEFS) $$($1_INCFLAGS) $$($1_CONFIG_FLAGS)
 
 # Compile: create object files from C source files.
 $1/%.o : %.c $1/%.d $1/cflags.txt $1/compiler.txt | $(BEGIN)
         @mkdir -p $$(@D)
         @$$(SILENT) || printf "$$(MSG_COMPILING) $$<" | $$(AWK_CMD)
-        $$(eval CMD := $$(CC) -c $$($1_CFLAGS) $$(GENDEPFLAGS) $$< -o $$@ && $$(MOVE_DEP))
+        $$(eval CMD := $$(CC) -c $$($1_CFLAGS) $$(INIT_HOOK_CFLAGS) $$(GENDEPFLAGS) $$< -o $$@ && $$(MOVE_DEP))
         @$$(BUILD_CMD)
 
 # Compile: create object files from C++ source files.
 $1/%.o : %.cpp $1/%.d $1/cxxflags.txt $1/compiler.txt | $(BEGIN)
         @mkdir -p $$(@D)
         @$$(SILENT) || printf "$$(MSG_COMPILING_CXX) $$<" | $$(AWK_CMD)
-        $$(eval CMD=$$(CC) -c $$($1_CXXFLAGS) $$(GENDEPFLAGS) $$< -o $$@ && $$(MOVE_DEP))
+        $$(eval CMD=$$(CC) -c $$($1_CXXFLAGS) $$(INIT_HOOK_CFLAGS) $$(GENDEPFLAGS) $$< -o $$@ && $$(MOVE_DEP))
         @$$(BUILD_CMD)
 
 $1/%.o : %.cc $1/%.d $1/cxxflags.txt $1/compiler.txt | $(BEGIN)
         @mkdir -p $$(@D)
         @$$(SILENT) || printf "$$(MSG_COMPILING_CXX) $$<" | $$(AWK_CMD)
-        $$(eval CMD=$$(CC) -c $$($1_CXXFLAGS) $$(GENDEPFLAGS) $$< -o $$@ && $$(MOVE_DEP))
+        $$(eval CMD=$$(CC) -c $$($1_CXXFLAGS) $$(INIT_HOOK_CFLAGS) $$(GENDEPFLAGS) $$< -o $$@ && $$(MOVE_DEP))
         @$$(BUILD_CMD)
 
 # Assemble: create object files from assembler source files.