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>

2 files changed, 43 insertions, 0 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) {