1 files changed, 78 insertions, 0 deletions
diff --git a/projects/bootloader/bootloader.c b/projects/bootloader/bootloader.c
new file mode 100644
index 0000000..1450c1a
--- /dev/null
+++ b/projects/bootloader/bootloader.c
@@ -0,0 +1,78 @@
+/*
+ * Bootloader to either install new firmware received from the MGMT UART,
+ * or jump to previously installed firmware.
+ *
+ */
+#include "stm32f4xx_hal.h"
+#include "stm-init.h"
+#include "stm-led.h"
+#include "stm-uart.h"
+
+/* Magic bytes to signal the bootloader it should jump to the firmware
+ * instead of trying to receive a new firmware using the MGMT UART.
+ */
+#define HARDWARE_EARLY_DFU_JUMP   0xBADABADA
+
+/* symbols defined in the linker script (STM32F429BI.ld) */
+extern uint32_t CRYPTECH_FIRMWARE_START;
+extern uint32_t CRYPTECH_FIRMWARE_END;
+extern uint32_t CRYPTECH_DFU_CONTROL;
+
+/* Linker symbols are strange in C. Make regular pointers for sanity. */
+__IO uint32_t *dfu_control = &CRYPTECH_DFU_CONTROL;
+__IO uint32_t *dfu_firmware = &CRYPTECH_FIRMWARE_START;
+/* The first word in the firmware is an address to the stack (msp) */
+__IO uint32_t *dfu_msp_ptr = &CRYPTECH_FIRMWARE_START;
+/* The second word in the firmware is a pointer to the code
+ * (points at the Reset_Handler from the linker script).
+ */
+__IO uint32_t *dfu_code_ptr = &CRYPTECH_FIRMWARE_START + 1;
+
+typedef  void (*pFunction)(void);
+
+/* This is it's own function to make it more convenient to set a breakpoint at it in gdb */
+void do_early_dfu_jump(void)
+{
+    pFunction loaded_app = (pFunction) *dfu_code_ptr;
+    /* Set the stack pointer to the correct one for the firmware */
+    __set_MSP(*dfu_msp_ptr);
+    /* Set the Vector Table Offset Register */
+    SCB->VTOR = (uint32_t) dfu_firmware;
+    loaded_app();
+    while (1);
+}
+
+int
+main()
+{
+    int i;
+
+    /* Check if we've just rebooted in order to jump to the firmware. */
+    if (*dfu_control == HARDWARE_EARLY_DFU_JUMP) {
+	*dfu_control = 0;
+	do_early_dfu_jump();
+    }
+
+    stm_init();
+
+    uart_send_string2(STM_UART_MGMT, (char *) "This is the bootloader speaking...");
+
+    /* This is where uploading of new firmware over UART could happen */
+
+    led_on(LED_BLUE);
+    for (i = 0; i < 10; i++) {
+	HAL_Delay(100);
+	led_toggle(LED_BLUE);
+    }
+
+    /* Set dfu_control to the magic value that will cause the us to call do_early_dfu_jump
+     * after rebooting back into this main() function.
+     */
+    *dfu_control = HARDWARE_EARLY_DFU_JUMP;
+
+    uart_send_string2(STM_UART_MGMT, (char *) "loading firmware\r\n");
+
+    /* De-initialize hardware by rebooting */
+    HAL_NVIC_SystemReset();
+    while (1) {};
+}