bootloader: consume per-board CAN pins, RGB LED and RAM limit

Wire the bootloader source to the per-board macros set by Inc/targets.h:

- sys_can_stm32_CANFD.c: map the main-firmware-style CAN_RX/TX_PORT/_PIN
  names onto the bootloader's FDCAN_* names (AF still defaults to AF9), so a
  board can route FDCAN to non-default pins (ARK uses TX on PB9).
- Mcu/g431/Inc/blutil.h: add RGB LED support keyed on RED/GREEN/BLUE_PORT/_PIN
  (open drain, active low) with a small per-port clock enable. No debug UART.
- main.c: re-add the LED hooks (no-op stubs when !USE_RGB_LED, plus a blink
  state machine that shows error/normal while stuck in the bootloader), and
  generalize the jump() RAM check to RAM_LIMIT_KB (default 64) so the ARK's
  112KB lets the bootloader accept an app whose stack sits above 64KB.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: tridge

Mcu/g431/Inc/blutil.h

@@ -175,6 +175,69 @@ static inline void bl_gpio_init(void)
   LL_GPIO_Init(input_port, &GPIO_InitStruct);
 }
 
+/*
+  RGB LED support, driven by per-board RED/GREEN/BLUE_PORT/_PIN from
+  Inc/targets.h (active low, open drain). Pins are LL_GPIO_PIN_x masks.
+ */
+#ifdef USE_RGB_LED
+static inline void bl_led_port_clock(GPIO_TypeDef *port)
+{
+#ifdef GPIOA
+  if (port == GPIOA) { LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOA); return; }
+#endif
+#ifdef GPIOB
+  if (port == GPIOB) { LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOB); return; }
+#endif
+#ifdef GPIOC
+  if (port == GPIOC) { LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOC); return; }
+#endif
+#ifdef GPIOD
+  if (port == GPIOD) { LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOD); return; }
+#endif
+#ifdef GPIOF
+  if (port == GPIOF) { LL_AHB2_GRP1_EnableClock(LL_AHB2_GRP1_PERIPH_GPIOF); return; }
+#endif
+}
+
+static inline void bl_led_init(void)
+{
+  bl_led_port_clock(RED_PORT);
+  bl_led_port_clock(GREEN_PORT);
+  bl_led_port_clock(BLUE_PORT);
+  LL_GPIO_SetPinMode(RED_PORT, RED_PIN, LL_GPIO_MODE_OUTPUT);
+  LL_GPIO_SetPinOutputType(RED_PORT, RED_PIN, LL_GPIO_OUTPUT_OPENDRAIN);
+  LL_GPIO_SetPinMode(GREEN_PORT, GREEN_PIN, LL_GPIO_MODE_OUTPUT);
+  LL_GPIO_SetPinOutputType(GREEN_PORT, GREEN_PIN, LL_GPIO_OUTPUT_OPENDRAIN);
+  LL_GPIO_SetPinMode(BLUE_PORT, BLUE_PIN, LL_GPIO_MODE_OUTPUT);
+  LL_GPIO_SetPinOutputType(BLUE_PORT, BLUE_PIN, LL_GPIO_OUTPUT_OPENDRAIN);
+  // LEDs off (open drain high = hi-Z = off)
+  LL_GPIO_SetOutputPin(RED_PORT, RED_PIN);
+  LL_GPIO_SetOutputPin(GREEN_PORT, GREEN_PIN);
+  LL_GPIO_SetOutputPin(BLUE_PORT, BLUE_PIN);
+}
+
+static inline void bl_led_on(void)
+{
+  LL_GPIO_ResetOutputPin(RED_PORT, RED_PIN);
+  LL_GPIO_ResetOutputPin(GREEN_PORT, GREEN_PIN);
+  LL_GPIO_ResetOutputPin(BLUE_PORT, BLUE_PIN);
+}
+
+static inline void bl_led_off(void)
+{
+  LL_GPIO_SetOutputPin(RED_PORT, RED_PIN);
+  LL_GPIO_SetOutputPin(GREEN_PORT, GREEN_PIN);
+  LL_GPIO_SetOutputPin(BLUE_PORT, BLUE_PIN);
+}
+
+static inline void bl_led_red_on(void)
+{
+  LL_GPIO_ResetOutputPin(RED_PORT, RED_PIN);
+  LL_GPIO_SetOutputPin(GREEN_PORT, GREEN_PIN);
+  LL_GPIO_SetOutputPin(BLUE_PORT, BLUE_PIN);
+}
+#endif // USE_RGB_LED
+
 /*
   return true if the MCU booted under a software reset
  */

bootloader/DroneCAN/sys_can_stm32_CANFD.c

@@ -382,6 +382,15 @@ static void can_init(void)
 void sys_can_init(void)
 {
   // Setup CAN RX and TX pins
+  // map main-firmware-style CAN pin names (from Inc/targets.h) onto FDCAN_*
+#if defined(CAN_RX_PORT) && !defined(FDCAN_RX_PORT)
+#define FDCAN_RX_PORT CAN_RX_PORT
+#define FDCAN_RX_PIN  CAN_RX_PIN
+#endif
+#if defined(CAN_TX_PORT) && !defined(FDCAN_TX_PORT)
+#define FDCAN_TX_PORT CAN_TX_PORT
+#define FDCAN_TX_PIN  CAN_TX_PIN
+#endif
 #ifndef FDCAN_RX_PORT
 #define FDCAN_RX_PORT GPIOA
 #define FDCAN_RX_PIN  LL_GPIO_PIN_11

bootloader/main.c

@@ -113,6 +113,49 @@ static uint16_t invalid_command;
 
 #include <blutil.h>
 
+// default no-op LED functions if not provided by blutil.h (USE_RGB_LED)
+#ifndef USE_RGB_LED
+static inline void bl_led_init(void) {}
+static inline void bl_led_on(void) {}
+static inline void bl_led_off(void) {}
+static inline void bl_led_red_on(void) {}
+#endif
+
+#ifdef USE_RGB_LED
+/*
+  blink RGB LEDs while stuck in the bootloader
+  - normal: blink all LEDs at ~2.5Hz
+  - error:  blink red only
+ */
+static uint16_t led_timer_start;
+static uint8_t led_blink_counter;
+static bool led_error_mode;
+
+static void __attribute__((unused)) bl_led_set_error(bool error)
+{
+  led_error_mode = error;
+}
+
+static void bl_led_update(void)
+{
+  const uint16_t now = bl_timer_us();
+  if ((uint16_t)(now - led_timer_start) < 25000U) {
+    return;
+  }
+  led_timer_start = now;
+  led_blink_counter++;
+  if (led_blink_counter & 0x08) {
+    if (led_error_mode) {
+      bl_led_red_on();
+    } else {
+      bl_led_on();
+    }
+  } else {
+    bl_led_off();
+  }
+}
+#endif // USE_RGB_LED
+
 #if DRONECAN_SUPPORT
 #include "DroneCAN/DroneCAN.h"
 #include "DroneCAN/sys_can.h"
@@ -348,7 +391,10 @@ static void jump()
    */
   const uint32_t *app = (uint32_t*)(MCU_FLASH_START + FIRMWARE_RELATIVE_START);
   const uint32_t ram_start = 0x20000000;
-  const uint32_t ram_limit_kb = 64;
+#ifndef RAM_LIMIT_KB
+#define RAM_LIMIT_KB 64
+#endif
+  const uint32_t ram_limit_kb = RAM_LIMIT_KB;
   const uint32_t ram_end = ram_start+ram_limit_kb*1024;
   if (app[0] < ram_start || app[0] > ram_end) {
     invalid_command = 0;
@@ -369,12 +415,16 @@ static void jump()
 #if DRONECAN_SUPPORT
   if (!DroneCAN_boot_ok()) {
     invalid_command = 0;
+#ifdef USE_RGB_LED
+    bl_led_set_error(true);
+#endif
     return;
   }
 
   sys_can_disable_IRQ();
 #endif
 
+  bl_led_off();
   jump_to_application();
 #endif
 }
@@ -769,6 +819,9 @@ static bool serialreadChar()
       }
       bl_timer_reset();
     }
+#endif
+#ifdef USE_RGB_LED
+    bl_led_update();
 #endif
   }
 
@@ -1094,6 +1147,7 @@ int main(void)
   bl_clock_config();
   bl_timer_init();
   bl_gpio_init();
+  bl_led_init();
 
 #ifdef BOOTLOADER_TEST_CLOCK
   test_clock();